Dissertations / Theses: 'BRAF35'

1

Carson, Robbie. "Targeting acute resistance mechanisms inhibition in BRAFMT CRC." Thesis, Queen's University Belfast, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.695267.

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Colorectal cancer (GRG) is the 3rd common cancer, and second leading cause of cancer associated mortality. Oncogenic mutations in the BRAF gene results in an altered protein structure, leading to constitutively activated MAPK signalling. Beneficial treatment strategies for this poor prognostic subgroup of GRG patients have yet to be identified. Hence this objective of this study was to identify novel treatment strategies in BRAF mutant GRG models. Our data has shown that MEK inhibition results in acute expression of pSTAT3, regulated through the c-METI JAK signalling axis. Taking a combined approach of JAKlMEK, or c-MET/MEK inhibition we have shown that these combinations results in significant increased apoptosis in BRAFMT GRG, and have potential as novel combinations. Furthermore, we are the first to show that MEK inhibition results in increased expression of the caspase 8 inhibitor c-FLlP, as a mechanism of resistance to apoptosis induction. Using a gene silencing and small-molecule inhibitor approach, we have identified that combined c-FLlP/MEK inhibition is a novel treatment strategy that may provide benefit for this subgroup of GRG patients.

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2

Beleboni, Rafaela Cardoso [UNESP]. "Traços impressionistas nos contos de Menalton Braff." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/91603.

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Nossa pesquisa de Mestrado procura apontar a permanência de traços impressionistas nos contos do livro premiado pelo Jabuti, em 2000, À sombra do cipreste (1999), de Menalton Braff. Para mostrar a construção dessas marcas na produção literária de Braff, recorremos a conceitos da teoria semiótica, sobretudo àqueles relacionados ao modo de presença da enunciação. A partir disso, pudemos depreender determinados elementos impressionistas presentes, sobretudo, nos contos À sombra do cipreste, No dorso do granito, O banquete e Adágio Apassionato. Dessa forma, há, na obra, do ponto de vista temático, a percepção do tempo e os ritos da memória, a relação do homem com o seu passado e o seu resgate numa situação do presente. Do ponto de vista formal, vários traços aparecem pontilhados. Sendo assim, há descrições sensoriais que dão cor, formato, som, gosto e cheiro às tensões, às dúvidas, às crises interiores das personagens que, na sua maioria, são sujeitos à flor da pele. Dentre as figuras sensoriais, a visão é predominante, figurativizada ponto-a-ponto pelos efeitos cromáticos, pelo circuito construído pelos olhares do narrador ou das personagens, pelo jogo de luz e sombra, a macro-figura impressionista recorrente na obra. A imagem criada torna-se, por meio do uso recorrente de figuras de linguagem, sugestiva. Em vários casos, há o efeito de borrão pontilhado, que indefine o objeto descrito para depois defini-lo.No entanto, esta pesquisa não se limita a desenvolver essa discussão. Procuramos, ainda, investigar, nos enunciados dos contos, as projeções da enunciação, evidenciadas nas entrevistas realizadas com o autor. Nesse sentido, procuramos contemplar quatro instâncias: a nossa leitura crítica de contos literários; a leitura do artista sobre a própria produção artística; o confronto entre essas duas leituras; o olhar do ficcionista...
Our Master research tries to indicate the permanence of impressionist traces in the tales obtained from the book A sombra do cipreste (1999) by Menalton Braff, awarded by Jabuti in 2000. We have used the concepts of semiotics theory to show these marks in Braff's work, especially those related to the way of enunciation presence. From these concepts we were able to infer some impressionist's elements present, especially in the tales, A sombra do cipreste, No dorso do granito, O banquete e Adágio Apassionato. From that, there is in the masterpiece a thematic point of view, the perception of time and rite of memory and the relation between the man with his past and its rescue to the present. From a formal point of view, many dotted traces show up. So there are many sensorial descriptions that give, color, shape, sound, taste and smell to the tensions, doubts, the characters inner crises, which are extremely evident subjects. Among the sensorial figures the predominant view symbolized point to point by the chromatics effects, the view connection built among the narrator and the characters, and by the light and shadow game, the impressionist appealing macro-figure in the masterpiece. The created image becomes significant through the use of language figures. In many cases there is the effect called dotted stain, which turns the described object indefinable to determine it later. However, this research was not limited in developing this discussion. We also tried to investigate the projection of the enunciation in the tale proposition that became evident in interviews done with the author. In those circumstances, we tried to observe four instances: our critical reading of literary tales, the authors point of view about his own work, the confrontation between these two readings and the fictionist's view facing the critics to his work. The results obtained point to agreements... (Complete abstract click electronic access below)

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3

Beleboni, Rafaela Cardoso. "Traços impressionistas nos contos de Menalton Braff /." Araraquara : [s.n.], 2007. http://hdl.handle.net/11449/91603.

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Orientador: Luiz Gonzaga Marchezan
Banca: Arnaldo Cortina
Banca: Tânia Pellegrini
Resumo: Nossa pesquisa de Mestrado procura apontar a permanência de traços impressionistas nos contos do livro premiado pelo Jabuti, em 2000, À sombra do cipreste (1999), de Menalton Braff. Para mostrar a construção dessas marcas na produção literária de Braff, recorremos a conceitos da teoria semiótica, sobretudo àqueles relacionados ao modo de presença da enunciação. A partir disso, pudemos depreender determinados elementos impressionistas presentes, sobretudo, nos contos "À sombra do cipreste", "No dorso do granito", "O banquete" e "Adágio Apassionato". Dessa forma, há, na obra, do ponto de vista temático, a percepção do tempo e os ritos da memória, a relação do homem com o seu passado e o seu resgate numa situação do presente. Do ponto de vista formal, vários traços aparecem pontilhados. Sendo assim, há descrições sensoriais que dão cor, formato, som, gosto e cheiro às tensões, às dúvidas, às crises interiores das personagens que, na sua maioria, são sujeitos à flor da pele. Dentre as figuras sensoriais, a visão é predominante, figurativizada ponto-a-ponto pelos efeitos cromáticos, pelo circuito construído pelos olhares do narrador ou das personagens, pelo jogo de luz e sombra, a macro-figura impressionista recorrente na obra. A imagem criada torna-se, por meio do uso recorrente de figuras de linguagem, sugestiva. Em vários casos, há o efeito de borrão pontilhado, que indefine o objeto descrito para depois defini-lo.No entanto, esta pesquisa não se limita a desenvolver essa discussão. Procuramos, ainda, investigar, nos enunciados dos contos, as projeções da enunciação, evidenciadas nas entrevistas realizadas com o autor. Nesse sentido, procuramos contemplar quatro instâncias: a nossa leitura crítica de contos literários; a leitura do artista sobre a própria produção artística; o confronto entre essas duas leituras; o olhar do ficcionista... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Our Master research tries to indicate the permanence of impressionist traces in the tales obtained from the book A sombra do cipreste (1999) by Menalton Braff, awarded by Jabuti in 2000. We have used the concepts of semiotics theory to show these marks in Braff's work, especially those related to the way of enunciation presence. From these concepts we were able to infer some impressionist's elements present, especially in the tales, "A sombra do cipreste", "No dorso do granito", "O banquete" e "Adágio Apassionato". From that, there is in the masterpiece a thematic point of view, the perception of time and rite of memory and the relation between the man with his past and its rescue to the present. From a formal point of view, many dotted traces show up. So there are many sensorial descriptions that give, color, shape, sound, taste and smell to the tensions, doubts, the characters inner crises, which are extremely evident subjects. Among the sensorial figures the predominant view symbolized point to point by the chromatics effects, the view connection built among the narrator and the characters, and by the light and shadow game, the impressionist appealing macro-figure in the masterpiece. The created image becomes significant through the use of language figures. In many cases there is the effect called dotted stain, which turns the described object indefinable to determine it later. However, this research was not limited in developing this discussion. We also tried to investigate the projection of the enunciation in the tale proposition that became evident in interviews done with the author. In those circumstances, we tried to observe four instances: our critical reading of literary tales, the authors point of view about his own work, the confrontation between these two readings and the fictionist's view facing the critics to his work. The results obtained point to agreements... (Complete abstract click electronic access below)
Mestre

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4

Braff, Roseli Deienno [UNESP]. "Saramago, Braff e seus personagens duplos: uma análise comparativa." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/94006.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Na leitura que fizemos dos romances O homem duplicado e Castelos de papel, guiou-nos o método comparativo de análise textual, tendo como norte a ideia de que o fato estético deve ser estudado à luz do fato histórico, em consonância com ele, e nunca dele apartado. Nessa linha de pensamento, constatamos que certo “ar do tempo” aproxima os autores José Saramago e Menalton Braff, que dialogam por meio da temática do duplo nas obras aqui investigadas. Nosso objetivo foi mostrar a existência dessa relação intertextual por meio da análise dos níveis temático, narrativo e discursivo dos romances, além do diálogo desses com a tradição literária. Ambos os autores fizeram uso, do ponto de vista da estrutura narrativa, de elementos característicos de outros gêneros, como a tragédia grega em O homem duplicado, e o drama em Castelos de papel. Além da temática do duplo, é a releitura do romance policial um dos pontos de contato mais evidente entre as duas obras, que se estruturam em torno de uma investigação. No entanto, os ficcionistas desmontam a velha fórmula: crime – investigação – desvendamento do enigma, e, na nova roupagem com que revestem esse subgênero, não há soluções tampouco culpados, mas indagações provocadoras – por essa razão a denominamos como falso romance policial. No nível temático, mostramos que o duplo como tema na literatura segue duas vertentes: o homogêneo, usualmente representado por gêmeos ou sósias idênticos, em que a identidade não é posta em questão, pois um mesmo personagem desempenha dois papéis; o heterogêneo, em que o usurpador ocupa uma forma definitiva, e tal divisão obriga o eu dilacerado a recuperar sua própria identidade. Tertuliano Máximo Afonso/ António Claro e Alberto Ribeiro/ sorveteiro são figuras do duplo heterogêneo. Exógeno, porque configurado extrinsecamente a ele, o duplicado de Tertuliano...
In our reading of the novels O homem duplicado and Castelos de papel, the comparative method of textual analysis has led us, with the idea that the aesthetic fact must be studied under the light of the historical fact, according to it and never separated from it. In this thought line, we verify that a certain “air of time” binds José Saramago and Menalton Braff in the sense of the dialogue through the way of the themes of the double, as presently in this investigated work. Our purpose was to show the existence of this intertextual relationship from the way of the analysis of the thematic, narrative and discursive levels of the novels, besides their dialogue with the literary tradition. Both the authors employed, under the point of view of narrative structure, characteristic elements of other genres, such as the Greek tragedy in O homem duplicado, and the drama in Castelos de papel. Besides the thematic of the double, it is the re-reading of the detective story one of the most evident contact points between both works that frame them around an investigation. However, the fictionists disassemble the old formula: crime − investigation − solving the enigma, and, in the new vesture in which they revest this subgenre, there are not solutions either guilty people, but provoking inquiries − due to this fact we regard them as false detective stories. In the thematic level, we show that the double as theme in literature follows two ways: the homogeneous one, habitually represented by twins or identical doubles, in which the identity is not questioned since the same character plays two roles; the heterogeneous one in which the usurper takes a definitive form, and such a division obliges the dilacerated I to pick up its own identity. Tertuliano/António Claro and Alberto/ice-cream peddler are characters of the heterogeneous double. Exogenous, because made up extrinsically to him... (Complete abstract click electronic access below)

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5

Braff, Roseli Deienno. "Saramago, Braff e seus personagens duplos : uma análise comparativa /." Araraquara : [s.n.], 2010. http://hdl.handle.net/11449/94006.

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Orientador: Luiz Gonzaga Marchezan
Banca: Ana Luiza Silva Camarani
Banca: Caio Márcio Poletti Lui Gagliardi
Resumo: Na leitura que fizemos dos romances O homem duplicado e Castelos de papel, guiou-nos o método comparativo de análise textual, tendo como norte a ideia de que o fato estético deve ser estudado à luz do fato histórico, em consonância com ele, e nunca dele apartado. Nessa linha de pensamento, constatamos que certo "ar do tempo" aproxima os autores José Saramago e Menalton Braff, que dialogam por meio da temática do duplo nas obras aqui investigadas. Nosso objetivo foi mostrar a existência dessa relação intertextual por meio da análise dos níveis temático, narrativo e discursivo dos romances, além do diálogo desses com a tradição literária. Ambos os autores fizeram uso, do ponto de vista da estrutura narrativa, de elementos característicos de outros gêneros, como a tragédia grega em O homem duplicado, e o drama em Castelos de papel. Além da temática do duplo, é a releitura do romance policial um dos pontos de contato mais evidente entre as duas obras, que se estruturam em torno de uma investigação. No entanto, os ficcionistas desmontam a velha fórmula: crime - investigação - desvendamento do enigma, e, na nova roupagem com que revestem esse subgênero, não há soluções tampouco culpados, mas indagações provocadoras - por essa razão a denominamos como falso romance policial. No nível temático, mostramos que o duplo como tema na literatura segue duas vertentes: o homogêneo, usualmente representado por gêmeos ou sósias idênticos, em que a identidade não é posta em questão, pois um mesmo personagem desempenha dois papéis; o heterogêneo, em que o usurpador ocupa uma forma definitiva, e tal divisão obriga o eu dilacerado a recuperar sua própria identidade. Tertuliano Máximo Afonso/ António Claro e Alberto Ribeiro/ sorveteiro são figuras do duplo heterogêneo. Exógeno, porque configurado extrinsecamente a ele, o duplicado de Tertuliano... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: In our reading of the novels O homem duplicado and Castelos de papel, the comparative method of textual analysis has led us, with the idea that the aesthetic fact must be studied under the light of the historical fact, according to it and never separated from it. In this thought line, we verify that a certain "air of time" binds José Saramago and Menalton Braff in the sense of the dialogue through the way of the themes of the double, as presently in this investigated work. Our purpose was to show the existence of this intertextual relationship from the way of the analysis of the thematic, narrative and discursive levels of the novels, besides their dialogue with the literary tradition. Both the authors employed, under the point of view of narrative structure, characteristic elements of other genres, such as the Greek tragedy in O homem duplicado, and the drama in Castelos de papel. Besides the thematic of the double, it is the re-reading of the detective story one of the most evident contact points between both works that frame them around an investigation. However, the fictionists disassemble the old formula: crime − investigation − solving the enigma, and, in the new vesture in which they revest this subgenre, there are not solutions either guilty people, but provoking inquiries − due to this fact we regard them as false detective stories. In the thematic level, we show that the double as theme in literature follows two ways: the homogeneous one, habitually represented by twins or identical doubles, in which the identity is not questioned since the same character plays two roles; the heterogeneous one in which the usurper takes a definitive form, and such a division obliges the dilacerated I to pick up its own identity. Tertuliano/António Claro and Alberto/ice-cream peddler are characters of the heterogeneous double. Exogenous, because made up extrinsically to him... (Complete abstract click electronic access below)
Mestre

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6

Cheung, Lai-Kay Maggie. "Characterisation of ^L597V BRAF in cancer." Thesis, University of Leicester, 2013. http://hdl.handle.net/2381/28016.

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BRAF is a component of the RAF/MEK/ERK signalling cascade which controls fundamental cellular activities, including proliferation, cell survival, differentiation and motility. Deregulation of this pathway is common in cancer and ~7% of cancers have a mutation in BRAF. Leu597 is the fifth most commonly mutated residue in BRAF-mutated human cancers, and a substitution to a valine is one of only seven BRAF mutations that are found in both cancer and a group of developmental syndromes known as RASopathies. A major question is how the mutation can be associated with both diseases. In this study, using an autochthonous model and HEK 293[superscript T] cells, [superscript L597V]BRAF was shown to have weak kinase and MEK/ERK-inducing activity. It did not induce morphological transformation or foci formation, nor confer a growth advantage or induce early immortalisation. Therefore, the mutation was found not to be a driver oncogene. [superscript L597V]BRAF mutations are found to co-exist with other oncogenic mutations in human cancer. Using cells derived from a conditional knock-in mouse model, we showed that [superscript L597V]BRAF synergises with [superscript G12D]Kras to induce cell changes more reminiscent of the high activity mutant [superscript V600E]Braf. Double mutant [superscript L597V]BRAF and [superscript G12D]Kras cells have higher Braf and Craf kinase activity than single mutants, which translates to higher Mek/Erk activity to a similar level to [superscript V600E]Braf. These cells were more morphologically transformed than Braf[superscript +/L597V] and Kras[superscript +/G12D] cells alone. RAF inhibitors induced paradoxical activation of Erk in [superscript L597V]Braf-expressing cells, and this was shown to be through heterodimerisation and activation of Craf. These results caution against the use of RAF inhibitors in treatment of RASopathy and cancer patients with the [superscript L597V]BRAF mutation. Aged Braf[superscript +/L597V] mice developed some predisposition to tumour formation. The tumours were benign, and one out of eight tumours was heterozygous for [superscript Q61L]Hras. This supports the idea that [superscript L597V]BRAF is insufficient to induce cancer, but epistatically modifies other oncogenes to promote cancer progression by hyperactivation of the Erk pathway.

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7

Sugita, Juliana Sayuri. "ANÁLISE DA MUTAÇÃO V600E DO GENE BRAF EM MELANOMAS CUTÂNEOS PRIMÁRIOS." Pontifícia Universidade Católica de Goiás, 2012. http://localhost:8080/tede/handle/tede/2350.

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Melanoma comprises about 4% of skin cancers, however, more than 95% of stage IV melanoma patients will die within five years and most patients will succumb in a year. The most commonly mutated gene in melanoma is BRAF V600E mutation, described in 40-70% of cutaneous melanomas. This mutation results in the substitution of valine for glutamic acid in codon 600, resulting in the active form of the protein. The objective of this study was to investigate the frequency of BRAF V600E mutation in patients diagnosed with melanoma in Goiânia, as well as the possible associations between this mutation and clinical-pathological aspects of the cases analyzed. Seventy seven cases of melanoma from the Pathology Departament of Araújo Jorge Hospital, in Goiânia, Goiás were analized. Molecular analysis was performed by PCR and RFLP. Descriptive and comparative statistical analysis with Chi-square test were used in this study. The results demonstrated the presence of V600E mutation in 54 (70,1%) patients with cutaneous melanoma and no statistically significant association was found between the presence of mutation with other prognostics parameters such as age, gender, sun exposure, anatomic location, presence of metastasis, histological subtypes and histological parameters (Breslow thickness, presence of ulceration, signs of regression, lymphocytic infiltration and presence of satellites). Our results suggest that BRAF V600E mutation is a common event in melanomas and represents an important molecular target for therapeutic approaches in the treatment of this neoplasia.
O melanoma representa 4% das neoplasias malignas da pele, no entanto, mais de 95% dos pacientes com melanoma estágio IV irão morrer em cinco anos e a grande parte dos pacientes irá sucumbir em um ano. O gene mutado mais comumente no melanoma é o BRAF e a mutação V600E é descrita em 40 a 70% dos melanomas cutâneos. Tal mutação resulta na substituição da valina por ácido glutâmico no códon 600, resultando na forma ativa desta proteína. O objetivo desse estudo consistiu em investigar a frequência da mutação V600E do gene BRAF, em pacientes diagnosticados com melanoma em Goiânia, bem como as possíveis associações, entre tal mutação e os aspectos clinico-patológicos dos casos analisados. Para isso foram analisados 77 casos de melanoma do Setor de Anatomia Patológica do Hospital Araújo Jorge, em Goiânia, Goiás. A análise molecular foi realizada por PCR e RFLP. Análise estatística descritiva e comparativa com o teste Chi-quadrado foi usado neste estudo. A mutação V600E do gene BRAF foi encontrada em 54 (70,1%) pacientes portadores de melanoma cutâneo e nenhuma associação estatisticamente significativa foi detectada entre a presença de mutação com outros parâmetros prognósticos como idade, gênero, exposição solar, localização anatômica, presença de metástases, subtipo histológico e parâmetros histológicos (índice de Breslow, presença de ulceração, sinais de regressão, infiltração linfocitária e presença de satélites). Nossos resultados permitem concluir que a mutação V600E de BRAF é um evento comum nos melanomas e que representa um alvo molecular importante para as abordagens alvo dirigidas no tratamento desta neoplasia.

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8

Ngeow, Kao Chin. "Post-translational modifications of BRAF and MITF." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:4f6ac084-55a7-4296-9a11-28af3979450d.

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Malignant melanoma is the deadliest and most aggressive form of skin cancer. Despite the development of targeted molecular therapies which specifically target oncogenic pathways in melanoma, melanoma remains highly refractory to treatment and prone to relapse. In order to develop more effective therapies, there is a need to investigate additional ways of manipulating aberrant molecular pathways in melanoma. To this end, we have identified novel sites of post-translational modifications in two oncogenic proteins that are known to play pivotal roles in driving melanoma tumorigenesis. We showed that BRAF, the most commonly mutated oncoprotein in melanoma, can be acetylated at K473 and K475 by the p300/CBP acetyltransferases. Importantly, acetylation of BRAF reduced its activity regardless of its mutational status at the commonly mutated V600 residue. We also identified a novel phosphorylation site targeted by GSK3 in microphthalmia-associated transcription factor (MITF), the melanocyte master regulator. GSK3 phosphorylation of S69, together with ERK-mediated phosphorylation of the nearby S73 residue, was found to promote MITF nuclear export via a previously undescribed nuclear export signal comprising of the S69, S73, M75, L78 and L80 residues. Importantly, phosphorylation-induced nuclear export was associated with reduced MITF activity, which may have important functional implications for melanocyte development and melanoma oncogenesis. In addition, we showed that the cyclin-dependent kinases CDK1 and CDK2 can also phosphorylate MITF at S73.

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9

merante, boschin isabella. "MUTAZIONI BRAF NEL CARCINOMA PAPILLARE DELLA TIROIDE." Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3426979.

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Introduction The papillary thyroid carcinoma (PTC) represents the majority of the differentiated thyroid cancers and its treatment is still debate considering the rare preoperative informations on the prognosis. Aim We proposed to assess the prognostic value of BRAF V600E mutation in PTC in view of a better therapeutic approach in terms of surgical and radiometabolic treatment. Materials and methods We considered 136 cases of PTC, between October 2008 and September 2009, subdivided in BRAF + and BRAF - and we compared these 2 groups on the basis of sex, age, histothype, TNM, size of the lesion, extracapsular extension, node metastases, multifocality, postoperative Tg level. BRAF V600E mutation analysis was performed, in parallel to classic cytology, in thyroid citoaspirates of 266 patients subdivided in the 5 cytodiagnostic cathegories (THY1, THY2, THY3, THY4, THY5) and subsequently underwent to thyroidectomy+/- node dissection. For each cytodiagnostic cathegory we considered the definitive histological diagnosis of PTC and the presence of BRAFV600E mutation. Results The BRAFV600E mutation is associated to age, histological variant of PTC, stages in patients with age>45 years. The prevalence of BRAF V600E mutation among histologically diagnosed PTC patients was 69% and it improved the FNAC diagnostic sensitivity from 84% to 88%. Conclusions The BRAF V600E mutation analysis increases the sensitivity of cytology and it represents an useful adjuvant tool in presurgical characterization of thyroid nodules. There is an association between the BRAFV600E mutation and clinicopathological characteristics of the CPT such as age, histological variant and stages.
Introduzione Il carcinoma papillare della tiroide (CPT) è il più frequente delle neoplasie tiroidee e il suo trattamento rimane per alcuni aspetti controverso, soprattutto per le scarse informazioni preoperatorie sul livello di aggressività del tumore stesso. Scopo dello studio Questo studio si propone di verificare il ruolo prognostico della mutazione BRAFV600E e di conseguenza la ricaduta di tale mutazione sul trattamento in termini di estensione dell’intervento chirurgico e terapia radioiodometabolica. Materiali e metodi Abbiamo considerato 136 casi di CPT all’esame istologico e li abbiamo distinti in 2 gruppi BRAF + e BRAF– confrontandoli sulla base delle seguenti variabili: sesso, età, istologia definitiva, diametro della lesione, stadiazione, metastasi linfonodali, infiltrazione della capsula, Tireoglobulina (Tg) nel follow up. Abbiamo inoltre ricercato la mutazione BRAFV600E su agoaspirato tiroideo in 266 casi sottoposti a intervento chirurgico di tiroidectomia totale +/- dissezione linfonodale tra ottobre 2008 e settembre 2009 distinti nelle 5 categorie citodiagnostiche (THY1, THY2, THY3, THY4, THY5) e per ciascuna categoria abbiamo verificato la diagnosi istologica di CPT distinguendo i casi BRAF + e BRAF –. Risultati La prevalenza di BRAF mutato nei pazienti operati con diagnosi istologica di CPT è risultata pari a 69%. La mutazione BRAFV600E si è associata a una maggior età, ad una minore frequenza di istotipo papillare variante follicolare e una più elevata frequenza di variante a cellule alte, ad una prevalenza degli stadi 3 e 4 nei pazienti di età > 45 anni. La ricerca di mutazione BRAFV600E ha incrementato la sensibilità della sola citologia dall’84 all'88%. Conclusioni Si conferma una associazione statisticamente significativa tra la presenza di mutazione in BRAF e caratteristiche clinico patologiche più aggressive del CPT, quali età più elevata, varianti istologiche a prognosi peggiore (variante tall cell), stadio più avanzato di malattia. La ricerca di mutazioni BRAF migliora la sensibilità della sola indagine citologica, in particolare in nodi la cui diagnosi citologica possa essere non conclusiva.

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Silva, Rosana Correa da. "ANÁLISE DA MUTAÇÃO V600E DO GENE BRAF E DETECÇÃO IMUNO-HISTOQUÍMICA DA PROTEÍNA BRAF EM CARCINOMAS PAPILÍFEROS DE TIREÓIDE." Pontifícia Universidade Católica de Goiás, 2012. http://localhost:8080/tede/handle/tede/2345.

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Papillary carcinomas are the most common tumors of the thyroid, corresponding to 80% of all tumors that affect the gland. In such tumors, a common mutation at the BRAF gene has been detected, comprising a nucleotide transversion, T1799A, at the exon 15 of gene. This mutation has been identified in about 50 % of the thyroid papillary carcinomas (TPC). Clinical and experimental studies have demonstrated important associations between BRAF mutations and different TPC clinical factors related to tumor progression, invasion and recurrence. The objective of this study was to analise BRAF protein expression, by using immunohistochemistry, and V600E BRAF mutations in a group of patients with thyroid papillary carcinoma. BRAF protein expression and V600E BRAF mutations were compared to TPC clinical and pathological aspects. The study group comprised 116 TPC patients that were selected at the Pathology Department of Hospital Araujo Jorge, in Goiânia. BRAF immunohistochemical analysis employed a labeled polymer peroxidase method and primary BRAF monoclonal antibody (clone F-7), Santa Cruz Biotechnology Inc. BRAF V600E molecular analysis was carried by PCR (Polimerase Chain Reaction) associated to RFLP (Restriction Fragment Length Polymorphism). Statistical analysis was performed by using univariate analysis (Chi-square test with Yates correction, and Fischer). Our results indicated that BRAF overexpression was detected in 54 TPC cases (46.0%), while BRAF V600E mutation was detected in 74 TPC cases (63.8%). Significant associations were detected between BRAF overexpression with distant metastasis (p=0.001) and tumor extrathyroidal extensions (p=0.0183). BRAF V600E mutations were significantly associated with lymph nodes methastasis (p=0.0385) and BRAF protein overexpression (p=0.0063).
Os carcinomas papilíferos são os tumores mais comuns da tireóide, sendo responsáveis por 80% de todos os cânceres da glândula. Nesses tumores, uma mutação comum no gene BRAF tem sido observada, compreendendo a transversão do nucleotídeo T1799A, localizado no exon 15, verificada em 50% dos carcinomas papilíferos de tireóide (CPT). Essa mutação acarreta a substituição do aminoácido valina na posição 600 da proteína, por ácido glutâmico, sendo assim designada V600E. Estudos experimentais e clínicos têm mostrado uma associação entre a mutação do gene BRAF e diferentes parâmetros clínicos de progressão, invasão e recorrência no CPT. O objetivo deste estudo foi detectar os níveis da proteína BRAF utilizando o método de imuno-histoquímica, e avaliar a mutação V600E do gene BRAF em um grupo de pacientes com carcinoma papilífero de tireóide. A detecção imuno-histoquímica da proteína BRAF e a mutação V600E do gene BRAF, foram comparadas em relação aos aspectos clínico-patológicos dos tumores. O grupo de estudo incluiu 116 pacientes com carcinoma papilífero de tireóide, selecionados no Setor de Anatomia Patológica do Hospital Araújo Jorge, em Goiânia-GO. A análise imuno-histoquímica utilizou o método da imunoperoxidase associada a polímeros e o anticorpo BRAF (clone F-7) Santa Cruz Biotechnology Inc. A análise molecular da mutação V600E do gene BRAF foi realizada por meio de PCR (reação em cadeia da polimerase) e RFLP (polimorfismo de comprimento de fragmentos de restrição). As análises estatísticas incluiram o teste do Chi-quadrado com correção de Yates e o teste exato de Fisher. Nossos resultados mostraram que a hiperexpressão de BRAF foi detectada em 54 casos (46%) e a mutação V600E do gene BRAF em 74 casos (63,8%). Dentre as associações investigadas, resultados significativos foram observados entre a hiperexpressão da proteína BRAF e extensão extra-tireoideana do tumor (p=0,0183). A presença da mutação V600E do gene BRAF foi associada as metástases linfonodais (p=0,0385) e à hiperexpressão da proteína BRAF (p=0,0063).

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Boussemart, Lise. "Inhibiteurs de BRAF dans le traitement du cancer : Contribution à l’étude des mécanismes de résistance et des effets secondaires paradoxaux." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA11T102/document.

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Les inhibiteurs de BRAFV600-, dont le vemurafenib, sont efficaces contre les tumeurs présentant cette mutation activatrice de la voie des MAPK, ce qui est le cas d’un mélanome sur deux. Mais la plupart des malades traités rechutent dans l’année, et développent des tumeurs paradoxales secondaires.Divers mécanismes de résistance aux inhibiteurs de BRAF ont été décrits, cette résistance passant soit par réactivation de la voie des MAPK, soit par activation de la voie parallèle Akt/mTor, soit par anomalie de régulation de l’apoptose. Dans le cadre de cette thèse, nous avons mis en évidence une nouvelle cible thérapeutique: l’initiation de la traduction cap-dépendante. L’augmentation de la traduction de certains ARNm en protéines est une étape capitale de l’expression des gènes dans les processus oncogènes. Une étape limitante de cette traduction est son initiation. La protéine eIF4E (eukaryotic Initiation Factor 4E) se lie à la coiffe m7GTP des ARNm et régule la synthèse protéique en fonction de ses partenaires 4EBP1 et eIF4G. Quand eIF4E est assemblé à eIF4G et eIF4A, on parle du complexe « eIF4F », situé au point de convergence de la voie des MAPK et de la voie Akt/mTor via 4EBP1. Ce complexe est nécessaire à la traduction des protéines de survie et de prolifération cellulaire ayant une structure secondaire complexe en 5’UTR. Pour déterminer le statut d’activation du complexe eIF4F dans des lignées cellulaires, nous avons réalisé une immunoprécipitation des protéines liées au cap (« cap-binding assay »). Nous avons observé que le vemurafenib entraînait une diminution d’eIF4G fixé à eIF4E dans les cellules sensibles mais aucune modification dans les lignées résistantes. Parallèlement, la fixation de 4EBP1 à eIF4E augmente sous vemurafenib pour les lignées sensibles. Pour confirmer ces résultats, nous avons utilisé la technique de « Proximity Ligation Assay » (PLA), qui nous a permis de visualiser les complexes eIF4E-eIF4G et eIF4E-4EBP1 sous forme de points fluorescents observables en microscopie. Le nombre de complexes eIF4E-eF4G était bien diminué dans les cellules sensibles sous vemurafenib ce qui n’était pas le cas dans les cellules résistantes. Parallèlement, le nombre d’interactions eIF4E-4EBP1 augmentait dans les cellules sensibles et restait stable dans les cellules résistantes. De même, dans les tumeurs de patients, le rapport des complexes eIF4E-eIF4G sur eIF4E-4EBP1 diminuait dans les métastases en réponse au vemurafenib puis réaugmentait lors des récidives tumorales. De plus, nous avons testé des composés ciblant la traduction cap-dépendante et plus particulièrement eIF4A : les flavaglines. Nous avons montré que leur capacité à cibler l’initiation de la traduction était corrélée à l’inhibition de la prolifération des lignées cellulaires résistantes. Enfin, nous avons testé l’une d’elles in vivo. Les résultats montrent un effet synergique de cette drogue combinée au vemurafenib et une inhibition de la croissance tumorale.Concernant l’autre inconvénient majeur des anti-BRAF, l’induction fréquente de tumeurs secondaires, nous avons visualisé, aussi par PLA, les dimères BRAF-CRAF pour la première fois dans une série de tumeurs paradoxales de patients, cutanées et extra-cutanées. Ces dimères sont significativement plus nombreux dans les tumeurs cutanées apparaissant sous anti-BRAF que dans une série tumeurs contrôles de même type.En conclusion, nous avons identifié un nouveau biomarqueur de résistance aux anti-BRAF, visualisable par PLA. Pour optimiser la réponse tumorale à ces thérapies ciblées, qui constituent le traitement de choix des mélanomes métastatiques mutés, nous proposons d’y associer un inhibiteur de l’initiation de la traduction. Nous avons en parallèle mis au point le PLA BRAF-CRAF dans les tumeurs paradoxales induites par les anti-BRAF, et nous avons identifié des sous-populations plus à risque de développer ce type de tumeurs
BRAFV600- inhibitors, including vemurafenib, are efficient against tumors harboring this MAPK pathway activating mutation, which is the case of ~50% of melanomas. But most of the patients under treatment progress within a year, and develop paradoxical secondary tumors. Most resistance mechanisms to drugs that target the BRAF and/or MEK kinases in cancer rely on reactivation of the RAS-RAF-MEK-ERK signal transduction pathway (ERK-dependent), on activation of the alternative PI3K-AKT-mTOR pathway (ERK-independent) or on modulation of the caspase-dependent apoptotic cascade. All three pathways converge to regulate the formation of the eIF4F translation initiation complex that binds to the 7-methyl-guanine cap at the 5’ end of mRNAs, thereby modulating mRNA translation of specific mRNAs. We show here that persistent formation of the eIF4F complex, comprising the eIF4E cap binding protein, the eIF4G scaffolding protein and the eIF4A RNA helicase, is associated with resistance to anti-BRAF, anti-MEK and to anti-BRAF + anti-MEK combinations in BRAFV600- mutant melanoma, colon and thyroid cell lines. Unresponsiveness to treatment and maintenance of eIF4F complex formation is associated with either reactivation of MAPK signaling or absence of ERK-independent decreased phosphorylation of the inhibitory eiF4E binding protein 4EBP1 or increased pro-apoptotic Bcl-2 modifying factor (BMF)-dependent degradation of eIF4G. Development of an in situ method shows by proximity ligation assay (PLA) that the formation of the eIF4F complex is decreased in tumors responding to anti-BRAF therapy and increased in resistant metastases. Strikingly, inhibiting the eIF4F complex, either by blocking the eIF4E-eIF4G interaction or by targeting eIF4A with small compounds is synergistic with BRAFV600- inhibition. The other main problem arising during anti-BRAF treatment is the frequent induction of secondary cutaneous and extra-cutaneous tumors, through the formation of BRAF-CRAF dimers that we visualized in vivo for the first time. In conclusion, we have identified by PLA a novel biomarker of resistance against BRAF inhibitors, which is also a promising therapeutic target. Combinations of drugs targeting BRAF (and/or MEK) and eIF4F may overcome most of the resistance mechanisms arising in BRAFV600- cancers. In parallel, we established a BRAF-CRAF PLA method in paradoxical secondary tumors induced by BRAF inhibitors, leading to the identification of several subpopulations more at risk of developing this type of tumors

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López, Fauqued Marta. "Preclinical Study of PI3K and BRAF Inhibitors in Malignant Melanoma / Estudio preclínico de inhibidores de PI3K y BRAF en melanoma maligno." Doctoral thesis, Universitat de Barcelona, 2010. http://hdl.handle.net/10803/1040.

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Malignant melanoma is the most lethal skin cancer with no effective therapeutic treatment in its metastatic stages. RAS and PI3K pathways have been shown to play a critical role in melanoma development and progression. In this study, we assessed the in vitro and in vivo inhibition potential of a BRAF inhibitor (Sorafenib, Bayer) and a PI3K/mTOR inhibitor (PI-103, PIramed-Genentech) in primary melanoma cell lines. We used primary cell lines isolated from spontaneous melanomas obtained in the UV induced HGF transgenic melanoma mouse model.

Although PI-103 and sorafenib inhibited melanoma in vitro cell proliferation and viability, the inhibition of RAS pathway was more effective. The combination of the two drugs showed a synergistic effect inhibiting RAS and PI3K pathways and in vitro melanoma cell proliferation in a cell line dependent manner. However, the combined treatment of orthotopic xenographs in immunocompetent FVB mice did not cooperate blocking tumor growth. Surprisingly, the in vivo treatment with PI-103 enhanced tumor growth. Our results also revealed that PI-103 caused immunosuppression inducing thymus atrophy and upregulating the intratumoral transcriptional levels of inmunosuppressors. In addition, PI-103 induced the antiapoptotic BH3 family proteins Mcl-1, Bcl-2 and BclXL, which correlated with the lower apoptotic rate observed within the PI-103 treated tumors.

These data indicates that due to melanoma heterogeneity, some precautions should be taken when using these inhibitors for treatment. Moreover, these results certainly make an argument for investigating unexpected effects of rational drug combinations on immunocompetent animal models before conducting clinical studies.

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Silva, Natali Fabiana da Costa e. [UNESP]. "Os hábitos da memória nos conflitos dos protagonistas de Menalton Braff em Que enchente me carrega? (2000) e Bolero de Ravel (2010)." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/127843.

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A presente pesquisa tem como corpus dois romances do escritor contemporâneo Menalton Braff - Que enchente me carrega? (2000) e Bolero de Ravel (2010), e busca descrever, em meio ao fluxo de consciência que representa o pensamento dos protagonistas, um número incessante de memórias que se repete do início ao final das narrativas: 13 memórias são apresentadas em Que enchente me carrega? e 15 memórias em Bolero de Ravel. Entendemos que a própria estrutura da narrativa se estabelece por meio da reiterada circularidade dos processos mnemônicos presentes nas duas obras, fixando o ritmo e a coerência do texto ficcional. Além disso, torna-se possível observar que as repetições instalam o modo de olhar dos narradores para o mundo, firmando o que eles veem, como percebem o que veem e, finalmente, como lidam com o que percebem. A partir disso, a pesquisa considera a possibilidade de que a estruturação dos romances por meio de repetições de situações de memória mostra-se dotada de inegável intencionalidade estética e estabelece a maneira singular do narrador braffiano. Este, ao narrar o seu processo de desagregação social e mental, revela o seu distanciamento do mundo, medida que intitularemos de processo da esfacelamento da personagem. As obras literárias serão analisadas a partir do instrumental teórico do fluxo da consciência, trazendo à luz os conceitos propostos por Robert Humphrey e Belinda Cannone. Esta abordagem contemplará, ao mesmo tempo, os processos históricos que estão na base da crise do romance e advento da ficção do fluxo da consciência
This research has as corpus two novels of the contemporary writer Menalton Braff - Que enchente me carrega? (2000) e Bolero de Ravel (2010) and seeks to describe, amid the stream of consciousness that represents the thinking of the protagonists, an endless number of memories that are repeated from the beginning to the end of the stories: 13 memories are presented in Que enchente me carrega? and 15 memories in Bolero de Ravel. It is understood that the very structure of the narrative is established through repeated circularity of mnemonic processes present in the two works, setting the pace and consistency of the fictional text. Moreover, it is possible to observe that repetitions establish how the narrators look at the world around, determining what they see, how they perceive what they see and finally how they deal with what they perceive. The research considers that the repetitions in the novels is endowed with undeniable aesthetic intentionality and that it constitutes a characteristic of Braff's narrator. The narrator, when narrating his own process of social and mental decay, creates the image of his disengagement in the world. We named this procedure as the process of disintegration of the character. The thesis will be analyzed from the theoretical tools of the stream of consciousness, bringing to light the concepts proposed by Robert Humphrey and Belinda Cannone. This approach will include, at the same time, the historical processes that underlie the crises of the novel and the advent of the stream of consciousness fiction

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Vercellino, Laetitia. "Contribution de différents biomarqueurs à l’élaboration d’une stratégie thérapeutique dans le mélanome BRAF muté." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC323/document.

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Le mélanome métastatique est resté longtemps synonyme de pronostic catastrophique en raison de la faible efficacité des traitements disponibles. Depuis quelques années, de nombreuses innovations thérapeutiques ont révolutionné la prise en charge de ces patients, avec l’autorisation de mise sur le marché de traitements modulateurs de l’immunothérapie d’une part et de thérapies ciblant la voie des MAP kinases destinées aux patients porteurs de la mutation BRAF (présente dans environ 50% des mélanomes) d’autre part.Les inhibiteurs de BRAF et de MEK sont à l’origine de réponses spectaculaires, mais le contrôle de la maladie est généralement limité dans le temps, avec l’apparition de résistances au traitement entraînant une progression de la maladie. Etablir des stratégies thérapeutiques permettant de retarder ou de contourner ces résistances s’avère donc primordial. Pour ce faire, des biomarqueurs ou outils prédictifs de la réponse, in vitro et in vivo, peuvent contribuer à mieux stratifier les patients, et personnaliser leur prise en charge.Dans une première partie, nous avons comparé l’apport respectif d’un traceur de prolifération cellulaire, la 18F-FLT, et du traceur de consommation de glucose le 18F-FDG, dans l’évaluation thérapeutique d’une xénogreffe de mélanome BRAF muté traité par un inhibiteur de BRAF. Nous avons confirmé la place prépondérante du 18F-FDG, et étayé l’intérêt des index volumiques pour le suivi thérapeutique, notamment avec la 18F-FLT.Dans une seconde partie nous avons évalué in vivo la capacité d’un schéma d’administration intermittente à retarder l’apparition de résistance par rapport à un schéma d’administration continue dans des xénogreffes BRAF mutées traitées par une combinaison d’inhibiteurs BRAF/MEK. Dans nos modèles expérimentaux, il ne semblait pas y avoir de supériorité de l’administration intermittente. Toutefois nos expérimentations n’ont pas permis de trancher de façon formelle la question.Dans une troisième partie, nous avons voulu reproduire le schéma d’administration intermittent ex vivo en utilisant la technique d’histocultures. Nous avons par ailleurs évalué la possibilité pour des histocultures issues de tumeurs de patients de prédire la réponse aux thérapies ciblées chez ces mêmes patients. Les histocultures semblent un outil fiable pour guider les choix thérapeutiques. La documentation des modifications génétiques et de l’hétérogénéité moléculaire du mélanome pourrait également inciter à adapter la stratégie en fonction de l’agressivité présumée du mélanome chez un patient donné
Metastatic melanoma has long been synonymous of dismal prognosis, due to the weak efficacy of available treatments. Numerous therapeutic innovations have profoundly modified the management of these patients, with marketing authorizations of therapies targeting the MAP Kinases pathway for patient with BRAF mutated melanoma (about 50% of patients) on the one hand and immune checkpoint inhibitors on the other hand.BRAF and MEK inhibitors result in dramatic responses, but disease control is generally short-lived, with onset of drug resistance leading to disease progression. Designing therapeutic strategies allowing delaying or bypassing this resistance phenomenon is of primary importance. Thus, in vitro and vivo biomarkers or tools predictive of response could help stratifying patients, and personalize each patient’s management.In the first part, we compared the respective value of a proliferation tracer, 18F-FLT, and of the glucose consumption tracer, 18F-FDG for therapeutic evaluation of a BRAF mutated melanoma xenograft, treated by a BRAF inhibitor. We confirmed the predominant role of 18F-FDG, and backed up the potential interest of volumetric parameters for therapeutic follow-up, especially with 18F-FLT.In a second part we assessed in vivo the ability of an intermittent schedule to delay resistance onset, compared with a continuous schedule in BRAF mutated xenografts treated by a BRAF/MEK inhibitors combination. In our experimental models, there did not seem to be any superiority for the intermittent schedule. However our experiments did not allow us to draw any final conclusions on the subject.In a third part, we tried to reproduce ex vivo the intermittent schedule with histocultures device. We also assessed the possibility for histocultures with patient derived tumours to predict response to targeted therapies in the same patients. Histocultures appear as a relevant tool to guide therapeutic choice. Determination of genetic modifications and molecular heterogeneity may also prompt tailoring therapeutic strategy depending on the supposed aggressiveness of a melanoma in a given patient

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Mitra, Devarati. "The Role of Pigmentation and Oncogenic BRAF in Melanoma." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10101.

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BRAF(V600E), the most commonly mutated oncogene in melanoma, is found in about half of patients. By hyperactivating the MAPK pathway, this mutation promotes cell growth and proliferation. Melanocytic BRAF(V600E) alone, however, is insufficient to cause melanoma and rather promotes the development of benign nevi (moles). The goal of our initial studies was to better understand how genetic and environmental risk factors interact with the BRAF(V600E) oncogene to induce melanoma. The two most prominent risk factors for melanoma development are exposure to ultraviolet (UV) radiation and pale skin pigmentation; particularly in the case of individuals with the “redhead” phenotype, who carry inactivating mutations in the MC1R G-protein coupled receptor. It has commonly been thought that redheads are at highest risk for melanoma development due to poor protection from genotoxic UV radiation from the sun. Using a melanocyte-specific, inducible Braf(V600E) mouse model, we have shown that an inactivating mutation in Mc1r which causes a redhead phenotype in mice, confers a significant UV-independent elevation in melanoma risk, relative to black and albino animals. The mechanism of accelerated UV-independent oncogenesis was found to be dependent on the synthesis of the red/yellow pheomelanin pigment. While these experiments were on-going, a novel small molecule inhibitor of the BRAF(V600E) oncogene, vemurafenib, began showing promising results in clinical trials. The observation that half of patients were experiencing significant tumor regression was unprecedented, but was soon followed by vemurafenib-resistant disease progression. Based on the fact that acquired drug resistance is a major obstacle to good therapeutic outcomes, we began investigating mechanisms of BRAF inhibitor resistance. A panel of BRAF(V600E) human melanoma cell lines that were initially sensitive to PLX4720 (a pre-clinical analog of vemurafenib), were chronically treated with the oncogenic BRAF inhibitor until resistance developed. These paired resistant and sensitive cell lines were characterized in terms of drug sensitivity and activation of cell signaling pathways. Multiple different patterns of drug resistance were found. The diversity of resistance mechanisms in these studies agrees with the diversity which others have found in the literature, suggesting that melanoma cells may be uniquely adaptable to circumventing BRAF(V600E) oncogene addiction.

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Canto, Alan Motta do. "Análise imunohistoquímica da mutação BRAF V600E em ameloblastomas mandibulares." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/23/23139/tde-05062017-104621/.

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O ameloblastoma é um tumor odontogênico agressivo, localmente invasivo e altamente recorrente. Estudos demonstram que é a neoplasia odontogênica benigna mais comum e eventualmente pode apresentar comportamento de lesões malignas. A detecção da mutação BRAF V600E tem sido demonstrada como uma das principais vias de proliferação tumoral dos ameloblastomas. Portanto, a identificação desses marcadores poderão ser úteis para elaborar estratégias mais eficientes de tratamento dessa patologia, bem como melhorar a qualidade de vida dos pacientes. Este estudo pesquisou a mutação BRAF V600E, por meio da técnica de imunohistoquimica, em ameloblastomas mandibulares bem como correlacionou com dados clínicos e imaginológicos relevantes. A amostra consistiu de 84 casos diagnosticados como ameloblastoma e localizados na mandíbula dos acervos do Serviço de Patologia Cirúrgica do Departamento de Estomatologia da FOUSP e do Serviço de Cirurgia Bucomaxilofacial do Hospital Erasto Gaertner, Curitiba, PR. Os blocos obtidos foram submetidos a reação imunohistoquímica para detectar a mutação da proteína BRAF e foram coletados todos os dados clínicos e imaginológicos dos pacientes como sexo, idade, tamanho do tumor, localização mandibular, aspecto radiográfico, tipo e subtipo histológico e status do tumor. Análise estatística foi realizada buscando estabelecer correlação entre o marcador BRAF e dados clínicos e imaginológicos. Como resultados, dos 84 pacientes, 44 eram pacientes do sexo masculino (52,38%) e 40 feminino (47,62%). A mediana da idade encontrada foi de 25,5 anos sendo que em 42 casos foi observada idade inferior a mediana (50%) e 42 superior (50%). Com relação a presença ou ausência da mutação BRAF V600E, 66 casos apresentaram positividade para o marcador estudado (78,57%) e 18 foram negativos (21,43%). Ao relacionar a expressão de BRAF com as variáveis, foi observado significância estatística para a variável localização (P= 0,0353) e tamanho do tumor (P=0,008). Não foi observado resultados com significância estatística com relação às variáveis sexo (P=0,969), idade (P=1,0), aspecto radiográfico (P=0,977), padrão histológico (P=0,910), subtipo histológico (P=0,5141) e status do tumor (P=0,336). Os autores concluíram que a mutação BRAF V600E é comum em ameloblastomas mandibulares e é mais frequente tumores maiores de 4 cm e na região posterior de mandíbula. Além disso, independe do tipo histológico do tumor, idade e sexo do paciente, aspecto radiográfico e status do tumor (primário x recorrente).
Ameloblastoma is an aggressive odontogenic tumour, being locally invasive and highly recurrent. Studies have demonstrated that it is the most common benign odontogenic neoplasia, sometimes exhibiting behaviour of malignant lesions. Detection of BRAF V600E mutation has been shown to be one of the main proliferation pathways of ameloblastomas. Therefore, the identification of these markers can be useful to elaborate more efficient treatment strategies for this pathology as well as to improve the patient\'s quality of life. This study investigated the BRAF V600E mutation in mandible ameloblastomas by using the immunohistochemical technique and by correlating clinical and imaging data of the patients. The sample consisted of 84 cases diagnosed as mandibular ameloblastoma, with all blocks being obtained from the Surgery Pathology Service of the FOUSP Department of Stomatology and the Maxillofacial Surgery Unit of the Erasto Gaertner Hospital, Curitiba, PR. The blocks were submitted to immunohistochemical reaction for detection of BRAF protein mutation, with clinical and imaging data such as age, gender, tumour size, mandibular location, radiographic aspect, histological type and subtype, and tumour status were collected. Statistical analysis was performed in order to establish a correlation between BRAF marker and clinical and imaging data. The results showed that, of the 84 patients, 44 were male (52.38%) and 40 female (47.62%). The median age was 25.5 years old, with 42 cases having age below the median (50%) and 42 above it (50%). With regard to the presence or absence of BRAF V600E mutation, 66 cases were found to be positive for the marker (78.57%) and 18 were negative (21.43%). The correlation between BRAF expression and variables showed statistical significances for mandibular location (P = 0.0353) and tumour size (P = 0.008), whereas no statistical significance was observed for gender (P = 0.969), age (P = 1.0), radiographic aspect (P = 0.977), histological pattern (P = 0.910), histological subtype (P = 0.5141) and tumour status (P = 0.336). The authors concluded that BRAF V600E mutation is common in mandibular ameloblastomas, with tumours larger than four cm being more frequent in the posterior region of the mandible. In addition, this pathology occurs regardless of histological type of the tumour, age, gender, radiographic aspect and tumour status.

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17

Lundberg, Ida. "Molecular understanding of KRAS- and BRAF-mutated colorectal cancers." Doctoral thesis, Umeå universitet, Patologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-133410.

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Colorectal cancer (CRC) is the third most commonly diagnosed malignancy in both men and women, and one of the leading causes of cancer-related deaths worldwide. One frequently mutated pathway involved in oncogenesis in CRC is the RAS/RAF/MAP kinase pathway. Oncogenic activation of KRAS and BRAF occur in 30‒40% and 5‒15% of all CRCs, respectively, and the mutations are mutually exclusive. Even though KRAS and BRAF are known to act in the same pathway, KRAS- and BRAF-mutated CRCs have different clinical and histopathological features. For example, BRAF mutation in CRC is tightly linked to microsatellite instability (MSI) and a CpG island methylator phenotype (CIMP), which is not seen in KRAS-mutated tumours. BRAF-mutated CRCs are also more often found in right-sided tumours. However, the underlying molecular reasons for these differences have not yet been defined. The overall aim of this thesis was to investigate molecular differences between KRAS- and BRAF-mutated CRCs to understand how KRAS and BRAF mutations differentially affect tumour progression. We used an in vitro cell culture system to explore molecular differences between KRAS- and BRAF-mutated CRCs and verified our findings using CRC tissue specimens from the Colorectal Cancer in Umeå Study (CRUMS). We found that BRAF mutation, but not KRAS mutation, was associated with expression of the stem cell factor SOX2. Furthermore, SOX2 was found to be correlated to a poor patient prognosis, especially in BRAF-mutated cancers. We further investigated the role of BRAF in regulation of SOX2 expression and found that SOX2 is at least partly regulated by BRAF in vitro. We continued by investigating the functional role of SOX2 in CRC and found that SOX2-expressing cells shared several characteristics with cancer stem cells, and also had down-regulated expression of the intestinal epithelial marker CDX2. There was a strong correlation between loss of CDX2 expression and poor patient prognosis, and patients with SOX2 expression were found to have a particularly poor prognosis when CDX2 levels were down-regulated. In conclusion, in these studies we identified a subgroup of BRAF-mutated CRCs with a particularly poor prognosis, and having a cancer stem cell-like appearance with increased expression of SOX2 and decreased expression of CDX2. Tumour progression is regulated by interactions with cells of the immune system. We found that BRAF-mutated CRCs were more highly infiltrated by Th1 lymphocytes than BRAF wild-type tumours, while the opposite was true for KRAS-mutated CRCs. Interestingly, we found that part of this difference is probably caused by differences in secreted chemokines and cytokines between KRAS- and BRAF-mutated CRCs, stimulating different arms of the immune response. Altered levels of expression of miRNAs have been seen in several malignancies, including CRC. We found that BRAF- and KRAS-mutated CRCs showed miRNA signatures different from those of wild-type CRCs, but the expression of miRNAs did not distinguish KRAS-mutated tumours from BRAF-mutated tumours. In summary, our findings have revealed possible molecular differences between KRAS- and BRAF-mutated CRCs that may explain some of the differences in their clinical and histopathological behaviour.

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Silva, Natalí Fabiana da Costa e. [UNESP]. "Sutiliezas entre o interno e o externo: literatura e sociedade nos contos de Menalton Braff." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/94001.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Nossa pesquisa de mestrado procura apontar as relações entre a literatura e o seu condicionamento social em À sombra do cipreste (1999) e A coleira no pescoço (2006), livros de contos de Menalton Braff, autor brasileiro contemporâneo. A análise de orientação sociológica surgiu porque os contos de Menalton, ao mesmo tempo em que proporcionam uma leitura de cunho intimista pelas crises das personagens, linguagem poética, fluxo de consciência, emprego da técnica impressionista e expressionista, entre outros aspectos, integram em sua estrutura as formas com que as relações sociais, valores e orientações ideológicas interferem nas personagens e contribuem para a economia do texto. Para mostrar as imbricações entre texto e contexto, recorremos ao método analítico de Antonio Candido, a crítica sociológica, baseado nas obras Literatura e Sociedade (1965) e Formação da literatura brasileira (1997). Além disso, nosso embasamento teórico está centrado em outros autores que dialogam, direta ou indiretamente, com a crítica sociológica de Candido, como João Alexandre Barbosa, (A leitura do intervalo. Ensaios de crítica, 1990, e Alguma crítica, 2002), René Wellek e Austin Warren, (Teoria da literatura, 1965), Luiz Costa Lima (Teoria da literatura em suas fontes, 2002) e Octavio Paz, (O arco e a lira, 1982). Propusemos uma divisão do corpus em quatro frentes temáticas, Morte/Memória, Relações familiares, Abandono/Solidão e Embate social como método que auxiliasse a leitura dos contos analisados (treze no total). Essa divisão, contudo, buscou apontar o tema sobressalente em cada conto e não propor uma leitura estanque das temáticas, uma vez que, de modo geral, cada narrativa transita entre os quatro grupos. Para essa divisão utilizamos Tomachevski (“Temática”, 1973) e o Dicionário de termos literários, de Massaud Moisés, 1974...
Our research tries to indicate the relationship between literature and society in the short stories of À sombra do cipreste (1999) and A coleira no pescoço (2006) by Menalton Braff, contemporary Brazilian author. The sociological reading arose because Menalton’s short stories, while providing an intimate reading because of the characters’ crises, poetic language, stream of consciousness, use of impressionist and expressionist technique in writing, among others characteristics, also make implicit the ways in which social relations, values and ideological orientations interfere with the characters and contribute to the economy of the text. To show the connections between text and context, we’ve used the analytical method of Antonio Candido, the sociological critic, based on the books Literatura e sociedade (1965) and Formação da literature brasileira (1997). Our theoretical framework also focuses on other authors that interact, directly or indirectly, with Candido’s sociological critic, as João Alexandre Barbosa (A leitura do intervalo. Ensaios de crítica, 1990, e Alguma crítica, 2002), René Wellek and Austin Warren, (Teoria da literatura, 1965), Luiz Costa Lima (Teoria da literatura em suas fontes, 2002) and Octavio Paz, (O arco e a lira, 1982). We have also proposed a division of the corpus into four thematic fronts, Death/Memory, Family Relationship, Abandonment/Loneliness and Social strike, as method which would help the reading of the short stories (thirteen in total). This division, however, sought to point the main theme in each story, but did not propose a reading of each theme tight, because each narrative moves among the four groups. To accomplish this division we’ve used Tomachevski (“Temática”, 1973) and the Dicionário de termos literários, by Massaud Moisés, 1974. From these theoretical assumptions, we sought to ascertain which social... (Complete abstract click electronic access below)

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19

Silva, Natali Fabiana da Costa e. "Sutiliezas entre o interno e o externo : literatura e sociedade nos contos de Menalton Braff /." Araraquara : [s.n.], 2011. http://hdl.handle.net/11449/94001.

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Orientador: Antônio Donozeti Pires
Banca: Márcia Valéria Zamboni Gobbi
Banca: Tânia Pellegrini
Resumo: Nossa pesquisa de mestrado procura apontar as relações entre a literatura e o seu condicionamento social em À sombra do cipreste (1999) e A coleira no pescoço (2006), livros de contos de Menalton Braff, autor brasileiro contemporâneo. A análise de orientação sociológica surgiu porque os contos de Menalton, ao mesmo tempo em que proporcionam uma leitura de cunho intimista pelas crises das personagens, linguagem poética, fluxo de consciência, emprego da técnica impressionista e expressionista, entre outros aspectos, integram em sua estrutura as formas com que as relações sociais, valores e orientações ideológicas interferem nas personagens e contribuem para a economia do texto. Para mostrar as imbricações entre texto e contexto, recorremos ao método analítico de Antonio Candido, a crítica sociológica, baseado nas obras Literatura e Sociedade (1965) e Formação da literatura brasileira (1997). Além disso, nosso embasamento teórico está centrado em outros autores que dialogam, direta ou indiretamente, com a crítica sociológica de Candido, como João Alexandre Barbosa, (A leitura do intervalo. Ensaios de crítica, 1990, e Alguma crítica, 2002), René Wellek e Austin Warren, (Teoria da literatura, 1965), Luiz Costa Lima (Teoria da literatura em suas fontes, 2002) e Octavio Paz, (O arco e a lira, 1982). Propusemos uma divisão do corpus em quatro frentes temáticas, Morte/Memória, Relações familiares, Abandono/Solidão e Embate social como método que auxiliasse a leitura dos contos analisados (treze no total). Essa divisão, contudo, buscou apontar o tema sobressalente em cada conto e não propor uma leitura estanque das temáticas, uma vez que, de modo geral, cada narrativa transita entre os quatro grupos. Para essa divisão utilizamos Tomachevski ("Temática", 1973) e o Dicionário de termos literários, de Massaud Moisés, 1974... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Our research tries to indicate the relationship between literature and society in the short stories of À sombra do cipreste (1999) and A coleira no pescoço (2006) by Menalton Braff, contemporary Brazilian author. The sociological reading arose because Menalton's short stories, while providing an intimate reading because of the characters' crises, poetic language, stream of consciousness, use of impressionist and expressionist technique in writing, among others characteristics, also make implicit the ways in which social relations, values and ideological orientations interfere with the characters and contribute to the economy of the text. To show the connections between text and context, we've used the analytical method of Antonio Candido, the sociological critic, based on the books Literatura e sociedade (1965) and Formação da literature brasileira (1997). Our theoretical framework also focuses on other authors that interact, directly or indirectly, with Candido's sociological critic, as João Alexandre Barbosa (A leitura do intervalo. Ensaios de crítica, 1990, e Alguma crítica, 2002), René Wellek and Austin Warren, (Teoria da literatura, 1965), Luiz Costa Lima (Teoria da literatura em suas fontes, 2002) and Octavio Paz, (O arco e a lira, 1982). We have also proposed a division of the corpus into four thematic fronts, Death/Memory, Family Relationship, Abandonment/Loneliness and Social strike, as method which would help the reading of the short stories (thirteen in total). This division, however, sought to point the main theme in each story, but did not propose a reading of each theme tight, because each narrative moves among the four groups. To accomplish this division we've used Tomachevski ("Temática", 1973) and the Dicionário de termos literários, by Massaud Moisés, 1974. From these theoretical assumptions, we sought to ascertain which social... (Complete abstract click electronic access below)
Mestre

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20

Gontijo, Antônio Paulo Machado. "ANÁLISE MOLECULAR DA MUTAÇÃO V600E DO GENE BRAF EM MICROCARCINOMA PAPILAR DE TIREÓIDE." Pontifícia Universidade Católica de Goiás, 2012. http://localhost:8080/tede/handle/tede/2363.

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Thyroid cancer is the commonest endocrine malignancy, with a rising incidence all over the world. This increasing incidence is almost exclusively due to the papillary thyroid cancer (PTC) and 30% to 50% of these tumors are papillary thyroid microcarcinomas (PTMC). The many score systems for risk stratification of these patients in low and high risk have been revealed to be unsatisfactory, leading to the search of a molecular marker wich could integrate a more reliable stratification system. BRAF V600E mutation is a frequent genetic event in the papillary thyroid carcinomas, that reflects its potential as a molecular marker in the PTMC. The aim of the present study was to evaluate the prevalence of such mutation in 80 paraffin embedded PTMC samples from the Pathology Department of the Hospital Araújo Jorge of Goiânia, Goiás, Brasil, obtained from patients operated between 1999 and 2006. Molecular analysis of the BRAF V600E mutation has been achieved by PCR and RFLP techniques. Statistical analysis included Chi-squared test with Yates s correction and Fisher s exact test. From the 80 cases of PTMC analysed, 73 (91.2%) were females, 47 patients (58.7%) were less than 45 years old and 33 (41.3%) were ≥ 45 years old. Lymph node metastasis were observed in 28 patients (35.0%) and extrathyroidal extension occurred in 19 cases (23.7%). Mutation BRAF V600E was observed in 50 cases (62.5%). There was no statistically significant association between clinicalpathologic parameters and the presence of the BRAFV600E. Our results showed that the BRAFV600E is a common genetic alteration in the PTMC, and it may represent an early event in the carcinogenesis of the thyroid gland. However, implications of this mutation in the prognostic of the PTMC were not observed.
O câncer de tireoide é a neoplasia maligna endócrina mais comum, com incidência crescente em todo o mundo. Esse crescimento é quase que exclusivamente às custas do carcinoma papilar da tireóide (CPT) e, atualmente, 30-50% desses tumores são microcarcinomas papilares de tireóide (MCPT). Os diversos sistemas de estratificação para classificação desses pacientes em baixo e alto risco têm se revelado insatisfatórios, levando à procura de um marcador molecular que possa compor uma estratificação mais efetiva. A mutação V600E do gene BRAF constitui um evento genético frequente dos carcinomas papilares da tireóide, refletindo seu potencial como marcador tumoral nos MCPT. O objetivo do presente estudo foi avaliar a prevalência dessa mutação em 80 espécimes de MCPT, oriundas do Serviço de Patologia do Hospital Araújo Jorge de Goiânia, de pacientes operados entre 1999 a 2006. A análise molecular da mutação V600E do gene BRAF foi realizada por meio das técnicas de Reação em Cadeia de Polimerase (PCR) e Polimorfismo de Comprimento de Fragmento de Restrição (RFLP). As análises estatísticas incluíram o teste do Qui-quadrado com correção de Yates e o teste exato de Fisher. Dentre os 80 casos de MCPT analisados, 73 (91,2%) eram do sexo feminino; 47 pacientes (58,7%) tinham idades abaixo de 45 anos e 33 (41,3%) tinham idades ≥ 45 anos. Metástases linfonodais foram observadas em 28 pacientes (35%) e 19 tumores (23,7%) apresentaram extensão extratiroidiana. A mutação V600E do gene BRAF foi observada em 50 casos (62,5%). Dentre os parâmetros clínicos e histopatológicos investigados no grupo de pacientes deste estudo, nenhuma associação estatisticamente significativa foi detectada em relação à presença da mutação V600E do gene BRAF. Nossos resultados demonstraram que a mutação V600E do gene BRAF é uma alteração genética comum nos MCPT, podendo representar um evento precoce na carcinogênese da glândula tireóide. Entretanto, implicações desta mutação no prognóstico dos microcarcinomas papilíferos de tiróide não foram observadas.

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21

Richardson, Jennifer. "Zebrafish as a model of BRAFV600E melanoma subtypes and Nevus biology." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/6493.

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The most frequent mutation identified in both benign nevi and malignant melanoma is the constitutively activating V600E substitution of BRAF. However, how additional mutations co-operate with BRAFV600E to promote subtypes of melanoma in animals is only beginning to be understood. In this thesis, I generate and analyze zebrafish BRAFV600E melanoma models and also develop the first animal model for BRAFV600E nevus recurrence. In my first data chapter, I develop a unique animal model of nevus recurrence. In people it is not uncommon for a nevus to recur following removal, even when no pigmented nevus cells remain. The biology of how and why this happens is unknown. By partial amputation of the nevus in the zebrafish tail fin, we described both nevus regrowth, as well as nevi that do not regrow. Utilising melanin as a lineage tracer, I was able to show that recurrent nevi are repopulated from an unpigmented precursor population. This suggested that BRAFV600E nevi are supported by an undifferentiated stem cell population that is recruited to regenerate and pigment the nevus after removal. In my second data chapter, I use genetics to develop BRAFV600E zebrafish models of melanoma. In collaboration with Dr. James Lister and Professor Jeroen den Hertog, I describe three differing models of zebrafish melanoma. All three models show progression to melanoma, and in collaboration with Dr. Marie Mathers I establish that while BRAFV600E is present in all three models, co-operating mutations affect melanoma pathology. In my third data chapter, I develop tools to study the molecular differences in the BRAFV600E melanoma models. I described the optimisation of a broad range of antibodies, raised against human peptides due to the lack of reliable antibodies in the zebrafish field. I use punch core biopsies of both zebrafish and human tumours, and whole sagittal sections of juvenile zebrafish, to show specific staining throughout many organs of the developing fish. I then use some of these antibodies to analyse molecular pathways in the melanoma models.

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22

Liu, Tianyi. "BRAF Inhibitors Stimulate CAFs to Drive Drug Resistance in Melanoma." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin162324201258474.

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23

Carlino, Matteo Salvatore. "BRAF mutant melanoma: prognosis; response and resistance to targeted therapy." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14010.

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The recent development of selective BRAF and MEK inhibitors has led to dramatic improvements in the response and survival of patients with BRAF mutant metastatic melanoma. Despite these advances the benefits of BRAF and MEK inhibitors are variable and often short-lived. This thesis addresses a number of questions regarding the biology and management of BRAF mutant melanoma. The prognostic significance of BRAF and NRAS mutations in metastatic melanoma is assessed finding these mutations are not prognostic. Predictors of response to BRAF inhibitors are examined finding an early heterogeneous FDG-PET scan response is associated with a shorter progression free survival in BRAF inhibitor treated metastatic melanoma. Pre-treatment MEK1P124 mutations are associated with a reduced response to BRAF inhibitors and the influence of this mutation may be circumvented with the use of MEK or ERK inhibitors. Finally treatment options after the failure of BRAF and/or MEK inhibitors are examined providing a biological rationale for treatment with these agents beyond progression and for the use of ERK inhibitors. These data add to the expanding literature regarding BRAF-mutant melanoma. The field continues to rapidly evolve with particular focus on the impact of immune checkpoint inhibitors and the potential role of combinatorial therapies involving kinase and immune regulators.

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Keil, Philipp [Verfasser]. "BRAF V600 Mutationen in spindelzelligen und desmoplastischen Melanomen / Philipp Keil." Ulm : Universität Ulm, 2018. http://d-nb.info/115193819X/34.

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Moka, Nagaishwarya, Kelley cross, Marianne Brannon, Janet Lightner, Megan Dycus, William Stone, Victoria Palau, and Koyamangalath Krishnan. "Delta-tocotrienol and simvastatin induces differential cytotoxicity and synergy in BRAF wild-type SK-MEL-2 and mutant BRAF SK-MEL-28 melanoma cancer cells." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/215.

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Targeting the mutant BRAF and immunotherapy are new approaches to the treatment of metastatic malignant melanoma that has significantly improved survival but is associated with significant toxicity and cost. Potent and specific BRAF inhibitors like vemurafenib and dabrafenib are superior to chemotherapy in treatment of BRAF mutant melanomas which represent nearly 50% of all melanomas. A less toxic approach to treatment of malignant melanoma is hence appealing. Delta-tocotrienol (DT3), an unsaturated vitamin E isoform, and simvastatin, an HMG-CoA reductase inhibitor have been shown to have anti-neoplastic properties. We studied the effects of these chemicals in both BRAF-mutated SK-MEL-28 and BRAF-wild type SK-MEL-2 melanoma cells. MTS assays were used to analyze cytotoxicity. SK-MEL-28 and SK-MEL-2 cells were cultured in MEM media containing 10% serum and plated in 96-well culture plates for 48 hours then treated with DT3 (0-80 µM), simvastatin (0-10 µM), or a combination and dosed again at 72 hours. SK-MEL-28 and SK-MEL-2 cells were grown in 60 mm plates and treated with DT3 at concentrations of 30 µM, simvastatin at concentrations of 10 µM and combination of DT3 and simvastatin at concentrations of 10 µM and 2 µM. Cell were lysed with RIPPA buffer with protease and phosphatase inhibitor after 6 hours of treatment. Protein concentration of cell lysates was measured spectrophotometrically (GLO Max Multi+, Promega), using a BCA protein assay kit. The samples were run in SDS PAGE and blotted onto nitrocellulose membranes. Membranes were incubated with antibodies against Hsp 70 (Enzo Life Sciences, Farmingdale, NY), Hsp 90 (Santa Cruz, Dallas, TX), pS6 and pERK (Cell Signaling, Danvers, MA) and pAKT. Using MTS assay, we found that DT3 (IC50 75.2 μM) and simvastatin (IC50 8.3μM) have cytotoxic effects on melanoma cell line SK-MEL-2, but not on the SK-MEL-28 cells DT3 and simvastatin at the concentrations studied (10-80 μM DT3) and (0.625- 10 μM simvastatin). Further studies determined that simvastatin decreased expression of pS6, pERK on SK-MEL-2 and not DT3. However, these effects are different in SK-MEL-28 cells where there is only decrease in expression of pS6; treated SK-MEL-2 cells also show over-expression of Hsp70 suggestive of a rescue effect leading to lesser cytotoxic activity. The selective cytotoxicity observed in wild type BRAF melanoma cell lines by DT3 and simvastatin warrants further research into the potential therapeutic use of these drugs. A differential cytotoxicity is shown by DT3 and simvastatin in malignant melanoma cells with selective more potency in wild type BRAF melanoma compared to mutant BRAF melanoma cells. Further studies will be undertaken to dissect the mechanistic basis of this differential response.

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Lo, Chi-chuen Evans. "A study of BRAF and RAS genes in papillary thyroid carcinoma." Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B31972007.

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Grasse, Katinka. "KRAS/BRAF-Mutationsanalysen und die immunhistologische Expression von p53 und p16." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-151228.

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Lo, Chi-chuen Evans, and 盧致泉. "A study of BRAF and RAS genes in papillary thyroid carcinoma." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31972007.

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Samuel, Jesvin John. "Translational studies in B-cell malignancies : studies on TP53 and BRAF." Thesis, University of Leicester, 2015. http://hdl.handle.net/2381/36233.

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This thesis contains two distinct parts: Current models of Chronic Lymphocytic Leukaemia (CLL) pathogenesis invoke specialised anatomical microenvironments that harbour proliferating cells. Such proliferating CLL cells are more resistant to current immuno-chemotherapeutic regimens than cells in the peripheral blood and are thought to be the cause of disease relapse. Using a system to recapitulate CLL proliferation centres in vitro, I have observed that CLL cells undergo proliferation. Unexpectedly, under these conditions an induction of wild-type TP53 protein was also observed in all cases of CLL analysed. The results reported here were undertaken to understand how CLL cells upregulate TP53 protein and proliferate. For reasons that remain unclear, TP53 is unable to transactivate its classic target genes to induce cell-cycle arrest or apoptosis. However, it remains able to trigger a full apoptotic response after further DNA damage and a higher threshold of protein levels is reached. We propose a model whereby oxidative stress induced by proliferation in CLL triggers TP53 protein expression. Hairy Cell Leukaemia (HCL) represents approximately 2% of all leukaemias, follows an indolent course and remains an incurable disease. Recently, virtually all HCL patients shown to carry the BRAFV600E mutation, thought to be a disease-defining event. The BRAF V600E mutation results in constitutive activation of the MEK-ERK pathway resulting in aberrant proliferation, and targeted inhibitors have shown efficacy in BRAFV600E positive tumours. We wanted to test whether this efficacy can be extrapolated to HCL. Here we report in vitro studies using PLX4720 and in vivo trial of Vemurafenib in a patient with refractory HCL. While BRAF inhibition showed no effect on HCL survival in vitro, it resulted in rapid loss of viability of hairy cells in vivo. The results obtained show that efficacy of BRAF inhibition achieved did not occur via the expected inhibition of MEK-ERK activation.

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Medina-Pérez, Paula Andrea. "Functional characterization of cancer- and RASopathies-associated SHP2 and BRAF mutations." Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17420.

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Deregulierung des RAS/MAPK Signalwegs führen nicht nur zur Krebsentstehung, sondern sind auch mitverantwortlich für Entwicklungsstörungen, dieals Keimbahnmutationen in Schlüsselregulatoren des MAPK Signalwegs zurückzuführen sind, werden aufgrund überlappender Phänotypen unter dem Begriff RASopathien subsumiert. Obwohl die Inzidenz für solide Tumore bei diesen Patienten gering ist, wird ein Zusammenhang zum Auftreten verschiedener Leukämieformen deutlich. Im Rahmen dieser Arbeit wurden Mutationen zweier Schlüsselregulatoren des MAPK Signalwegs, PTPN11 und BRAF, hinsichtlich ihrer Fähigkeit zur neoplastischen Transformation analysiert. Zur Durchführung funktioneller Assays wurden Zelllinien mit lentiviraler Vektoren mit NS-, LS- oder NS und Leukämie-assoziierten SHP2 oder CFC-assoz. BRAF Mutationen (Mut), generiert. Die Testung des neoplastischen Potentials erfolgte anhand nicht-tumorigenen humanen sowie an 208F Ratten-Zelllinie. SHP2/BRAF-Mutationen haben eine spindel-ähnliche Zellmorphologie, Proliferation sowie das Dichte- und Anker-unabhängiges Wachstum in 208F gefördert. Diese Ergebnisse sprechen dafür, dass RASopathie-assoziierte Mutationen zu einem Transformationsphänotyp führen können, ähnlich wie die klassischen Ras Onkogenen. Um zu testen, ob Mut-SHP2 das in vivo Tumorwachstum beeinflusst, wurden SHP2-208F-Zellen in Nacktmäuse injiziert. Eine Förderung des Tumorwachstums konnte sowohl durch mut- als auch durch wt-SHP2 beobachtet werden. RASopathie-assoziierte mutierte Proteine führten auch zu einer moderaten Aktivierung des MAPK-Signalwegs. Eine erhöhte Bindungsstärke zu GAB1 konnte mittels ein TAP-Assay ermittelt werden. Auf transkriptioneller Ebene konnte einer Gensignatur, die sowohl durch RASopathien als auch der klassischen onkogenen BRAF identifiziert werden.Die Ergebnisse dieser Studie können für ein besseres Verständnis der Downstream-liegenden Mechanismen von RASopathie-bezogenen Signalwegen und ihrer Beteiligung an der Tumorprogression beitragen
Deregulation of the Ras/MAPK signaling is implicated in a variety of human diseases, including cancer and developmental disorders. The RASopathies are characterized by an overlapping phenotype in patients and result from germline mutations in key regulators of the MAPK signaling cascade. Although the incidence of solid tumors is rather low, reports on different leukemia forms have increased. In this work, a group of mutations in the genes PTPN11 and BRAF were selected for expression in cell lines for a comprehensive molecular and phenotypic characterization. Non-tumorigenic human cell lines and the rat 208F fibroblasts were transduced with lentiviral particles with SHP2/BRAF wildtype (wt), Noonan (NS)-, NS- and leukemia- or LS–associated SHP2 mutations (mut) and CFC-associated BRAF mutations to identify their potential roles in neoplastic transformation. Mutations in both genes promoted cell morphology alterations, cell proliferation, density- and anchorage-independent growth in rat fibroblasts. These results suggested that RASopathies-associated mutations in both genes confer a transformation phenotype in vitro similar to the classical oncogenes. To investigate whether mutations in SHP2 contribute to tumor growth in vivo, 208F cells expressing wt/mut SHP2 were injected in nude mice. Both wt/mut SHP2 expressing cells promoted tumor growth. Additionally, RASopathies-associated mutant SHP2 and BRAF proteins constitutively activate the MAPK signaling in a moderate manner compared to oncogenic BRAF. To identify modifications in the protein interaction of mut-SHP2, TAP assays were performed. Mut-SHP2 proteins showed an increased binding strength to GAB1 compared to wt. Finally, a microarray analysis revealed a gene cluster commonly regulated in both RASopathies and the oncogenic BRAF. The findings of this work might be useful for a better understanding of the downstream mechanisms of RASopathies-related signaling and their involvement in cancer progression.

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Vergani, E. "BRAF AND MAPK PATHWAY MOLECULES FOR TARGETED THERAPY OF MALIGNANT MELANOMA." Doctoral thesis, Università degli Studi di Milano, 2012. http://hdl.handle.net/2434/173422.

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The clinical activity of the BRAF inhibitor PLX4032 (vemurafenib) in patients with BRAFV600E mutant melanoma is limited primarily by the development of resistance leading to tumor progression. Strategies to overcome primary and acquired resistance are required. In a panel of 27 genetically characterized patient-derived melanoma cell lines the sensitivity to PLX4032 was dependent on BRAFV600E and independent from other gene alterations that commonly occur in melanoma, such as CDKN2A, and mutations of TP53, PTEN loss, and BRAF and MITF gene amplification. To investigate the molecular basis underlying acquired resistance to BRAF inhibitor, PLX4032-resistant cells were derived from a high sensitive BRAFV600E melanoma cell line, and used as a model. The resistant variant line showed increased AKT and ERK phosphorylation and enhanced IGF-1R/PI3K signaling. Combined treatment with PLX4032 plus PI3K inhibitors resulted in significant cell growth inhibition by decreasing pAKT and pERK signaling. To explore molecular mechanisms underlying primary resistance two melanoma cell lines lacking sensitivity to PLX4032 were used as models. Resistance to PLX4032 was maintained after CRAF down-regulation by siRNA, indicating that CRAF is not involved in the activation of ERK in the resistant cell lines. Treatment with the MEK inhibitor UO126 inhibited cell growth and decreased ERK phosphorylation indicating alternative activation of MEK-ERK signaling. Genetic characterization by MLPA and analysis of pTyr signaling by MALDI-TOF mass spectrometry revealed the activation of MET and SRC signaling, associated with the amplification of MET and of CTNNB1 and CCND1 genes, respectively. Testing of co-inhibition of the MET, SRC and MAPK signaling pathways by the combined treatment with the MET inhibitor, SU11274 or the SRC inhibitor, BMS-354825 plus PLX4032 resulted in a significant inhibitory effect on melanoma cell proliferation, survival, migration and invasive capacity. These results support combinatorial approaches targeting MAPK pathway at different nodes and intercepting parallel signal transduction pathways as a strategy to override resistance to BRAF inhibitors.

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Arnoux, Fanny. "Origine de l'apparition d'auto-anticorps dans la polyarthrite rhumatoïde." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4095.

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La Polyarthrite Rhumatoïde (PR) est une maladie auto-immune chronique qui détruit les articulations. Les auto-anticorps (AAc) les plus spécifiques sont dirigés contre des protéines citrullinées (ACPA). Environ 30% des patients ont des AAc dirigés contre la protéine B-Raf. Les ACPA sont des IgG produits sans réponse lymphocytaire T (LT) détectable contre les protéines citrullinées. Les enzymes PAD, responsables de la citrullination, sont la cible d’AAc dans la PR. Les LT pourrait être dirigés contre les PAD. Les LB produiraient des IgG contre les PAD et les protéines citrullinées, du fait qu’elles soient fixées aux PAD durant leur citrullination. Pour tester ce modèle, nous avons injecté des PAD à des souris et suivi les LT et les Ac anti-PAD ainsi que les ACPA. Nous avons montré que l’immunisation par PAD induit des LT anti-PAD, des Ac anti-PAD ainsi que des Ac anti-peptides de fibrinogène citrulliné.B-Raf est une ser/thr kinase de la voie des MAPK impliquée dans l’inflammation et l’activation des LT. Les LT de patients PR ont une sur-activation de la voie des MAPK, induisant une rupture de tolérance envers les auto-antigènes. Notre hypothèse est que des mutations du gène BRAF pourraient être à l’origine des AAc anti-B-Raf. Nous avons identifié la présence d’une mutation du gène BRAF entrainant la substitution de la valine en alanine en position 600 (V600A) qui est trouvée en plus grande quantité dans les cellules du sang périphérique et les LT des patients PR. V600A n’est pas corrélée à la présence d’AAc anti-B-Raf, mais augmente l’activité kinase de B-Raf qui pourrait activer la voie des MAPK dans les LT et une rupture de tolérance envers les auto-antigènes
Rheumatoid Arthritis (RA) is a chronic inflammatory autoimmune joint disease. RA most specific autoantibodies (AAb) recognize citrulline proteins (ACPA). 30% of patients with RA have anti-B-Raf AAb. ACPA are IgG that arise in the absence of associated T cell responses. PAD enzymes, responsible for the citrullination, are also targets of AAb in RA. We thus propose a mechanism to explain the emergence of ACPA. We hypothesize that anti-citrullinated protein immunization arises because, at first, PAD is recognized by T cells, which, in turn help the production of AAb to neighbor proteins citrullinated by PAD. To test this model, we primed mice with PAD proteins and looked for immune response to PAD and citrullinated proteins. We found that PAD immunization leads to T cell response, Ab anti-PAD as well as anti-citrullinated fibrinogen peptides Ab production. Anti-PAD immunization could induce anti-citrullinated protein immunization.B-Raf, a ser-thr kinase of the MAPK signalling pathway, is involved in inflammation and in T cell activation. An overexpression of B-Raf is observed in T cells from RA patients increasing T cell activation to autoantigens. Our hypothesis is that BRAF gene mutations could trigger a rupture of tolerance and AAb production in RA. We have identified a BRAF mutation, a valine residue at position 600 is substituted by an alanine (V600A). V600A is found more often and at greater quantities in patients with RA, noteworthy in their T cells. This mutation does not correlate with Anti-B-Raf AAb presence but this is a strong enhancer of B-Raf kinase activity. This could lead to abnormal T cells activation and explain tolerance rupture in RA

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Neyra, Jennifer Eliana Montoya. "Modulação dos efeitos citotóxicos dos vemurafenibe pela cloroquina em células de melanoma maligno G-361: papel da dermicidina." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/42/42136/tde-30012018-101101/.

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Neste estudo foram avaliados os efeitos farmacológicos do vemurafenibe (inibidor BRAFV600E) e da cloroquina (inibidor de autofagia) na viabilidade celular e crescimento tumoral das sublinhagens de melanoma:G361 pLKO que expressa dermicidina e G361 IBC I com silenciamento da expressão. As células G-361 responderam a vemurafenibe (2 μM) e cloroquina (100 μM), isoladamente ou combinadas, com aumento apoptose, e redução das taxas de senescência. Vemurafenibe (50 mg/kg / 21 dias) inibiu o crescimento tumoral em camundongos imunodeficientes independente da expressão da DCD. A combinação com Cloroquina (30 mg/kg) a cada 24 horas, acelerou, enquanto a cada 72 horas, reduziu o crescimento tumoral. Os tumores apresentaram alterações morfológicas e núcleos atípicos; e não expressaram os marcadores S100, HMB-45, Mela-A ou citoqueratinas. Este trabalho confirmar a eficácia do vemurafenibe e sugere o potencial adjuvante da cloroquina no tratamento de melanomas. O estudo também confirma o papel da dermcidina como oncogne e fator de crescimento de células de melanoma maligno.
In this study we evaluated the pharmacological effects of vemurafenib ( inhibitor BRAFV600E) and chloroquine (autophagy inhibitor) in cell viability and tumor growth of two melanoma cell lines identified as G-361 pLKO, which expresses dermcidin, and G361 IBC I which silenced DCD expression. G-361 melanoma cells responded to vemurafenib (1-2 μM) and chloroquine (50-100 μM) alone or combined, with increased apoptosis rates, while decreasing senescent cells. Vemurafenib (50 mg/kg / 21 days) inhibited melanoma growth in immunodeficient mice independent of dermicidin. Chloroquine (30 mg/kg) in combination with vemurafenib, accelerated (at 24 hour interval), and reduced (at 72 hours interval), melanoma growth. Tumor tissues showed atypical cell morphology and nuclear histological patterns and melanocytic differentiation biomarkers S100, HMB-45, Melan-A or pancytokeratins were not. This work confirms the efficacy of vemurafenib and suggests potential adjuvant effect of chloroquine. It also confirms the role of dermcidin as growth factor and oncogene for melanoma cells.

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Baxter, Eva Louise. "Investigating the association between BRAFV600E and methylation in sporadic colon cancer." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/6525.

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Aberrant methylation of CpG island promoters is a frequent observation in cancer and is known to affect many genes, including tumour suppressor genes. Genes with methylated promoters are usually repressed and inactive, and there is good evidence that most genes that become methylated in cancer are already repressed in the normal tissues from which tumours arise. However, the methylation of some genes appears to arise at previously active loci, suggesting either a stochastic epigenetic event or that these genes are somehow predisposed to becoming methylated. The DNA mismatch repair gene MLH1 is expressed in normal colonic epithelial cells but methylated and down-regulated in some sporadic mismatch repair-deficient colon tumours. These tumours are almost invariably associated with the simultaneous methylation of multiple cancer-specific loci, termed the CpG island methylator phenotype (CIMP) and an activating mutation of BRAF (V600E), raising the possibility that a hypermethylator phenotype may arise in cancer in direct association with a specific genetic alteration. The possibility that MLH1-deficiency caused BRAF mutation was discounted as genetic deficiency of MLH1 is not associated with BRAFV600E. I explored the possibility that BRAFV600E might induce MLH1 methylation but found no evidence in support of this. I then focused on factors that might mediate CIMP gene methylation, of which MLH1 methylation is known to be a part. Bioinformatic analysis of the genes methylated in BRAFV600E colon tumours indicated a significant enrichment in binding sites for the transcription factor MAZ (MYC-associated zinc finger protein). I hypothesised that loss of MAZ might lead to MLH1 down-regulation and its subsequent methylation. In this thesis I provide evidence that both MAZ and MLH1 expression are deregulated during normal colonic epithelial differentiation. The down-regulation of MAZ by RNA interference led to a reduction in MLH1 expression and methylation of its promoter. I speculate that MLH1 methylation may be associated with BRAF mutation because transformation by BRAFV600E allows progenitor cells to undergo a degree of differentiation whilst maintaining their malignant proliferation. I speculate that it is during this process of differentiation that MLH1 becomes susceptible to methylation.

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González, Sánchez Elena. "Study of the cooperative effect of UVR, BRAF and LKB1 in melanoma." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667375.

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Entender los mecanismos moleculares relacionados con la melanomagénesis es clave a la hora de encontrar nuevas estrategias preventivas y terapéuticas contra esta letal enfermedad. La epidemiología indica que hay factores genéticos y medioambientales asociados con el desarrollo y la progresión del melanoma. En este estudio, hemos generado el modelo animal B/L/UV que nos permite estudiar la cooperación entre el oncogén, BrafV600E, el factor medioambiental, de la radiación ultravioleta (UVR) y la pérdida del supresor tumoral, Lkb1. En resumen, el modelo animal B/L/UV presentado aquí es un potente sistema para estudiar la patogénesis del melanoma. Este modelo animal demuestra el importante rol de la UVR en la prevención de la senescencia inducida por BrafV600E, un requisito imprescindible en la progresión del melanoma en este específico contexto genético. Además, otro hecho evidente en la importancia de Lkb1 en la inducción in vivo de esta enfermedad, que tiene un efecto relevante en los tumores, afectando su iniciación, inestabilidad genética y su heterogeneidad histológica. El análisis genético de los tumores destaca el papel de las vías de señalización Rho, Netrin1 y SAPK/JNK en la melanomagénesis.
Understanding the molecular mechanisms related with melanomagenesis is key in order to find new preventive and therapeutical approaches against this lethal disease. Epidemiology indicates that there are genetic- and environmental-factors associated with melanoma development and progression. In this study, we have generated the B/L/UV animal model that allows us to study the cooperation between the oncogene, BrafV600E, the environmental insult, ultraviolet radiation (UVR), and the loss of a tumor suppressor, Lkb1. In summary, the B/L/UV animal model presented here is a strong system to study the melanoma pathogenesis. This animal model demonstrates the important role of UVR in preventing the BrafV600E-induced senescence, a requisite in melanoma progression in this specific mutational context. Moreover, a patent fact is the importance of Lkb1 in in vivo induction of this disease, which has a relevant effect in the tumors, affecting its onset, its genetic instability, and its histological heterogeneity. The genetic analysis of tumors highlights the important role of Rho-, Netrin1- and SAPK/JNK-signaling pathway in melanomagenesis.

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Safaee, Ardekani Gholamreza. "Prognostic role of BRAF in human cutaneous melanoma : gene versus protein expression." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54855.

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Melanoma is the deadliest type of skin cancer with an increasing incidence for past two decades. Once melanoma is metastasized (cancer cells are spread out through the body) there is no effective treatment available and 84% of the patients die within 5 years. However, the discovery of braf mutation in melanoma increased the hope for developing new treatments. We first evaluated the effect of braf V600E mutation on melanoma patient survival. In a systematic review we revealed that patients with braf V600E mutation have almost two times more risk of death compared with patients with wild type braf. Next we evaluated the correlation of brafV600E mutation with protein expression. We found that compared with nevi samples, BRAF protein expression was remarkably increased in primary melanomas and further increased in metastatic melanoma patients. Higher BRAF protein expression was significantly correlated with other poor prognosis factors and lead to a significant worse five-year survival. However, we did not find a significant correlation between BRAF protein expression and braf V600E mutation. In our attempt to investigate the cause of induced BRAF protein, we found novel expression of BRAF splice variants (BRAFsv) in both melanoma patients and cell lines. We identified new kinase-dead BRAFsv, which have a dominant negative effect on full-length BRAF and are able to suppress downstream signaling and reduce melanoma cell proliferation. These variants were highly expressed in primary melanoma compared to normal samples, while the expression was decreased in metastatic and more aggressive types of melanoma. In addition, kinase-dead BRAFsv showed a protective effect on patient survival, which remained significant at the presence of full-length BRAF. Thus, patients who expressed the kinase-dead variant and had lower levels of full-length BRAF expression showed the best survival rate in 5 years. Our invitro analysis also indicates that over expression of kinase-dead BRAFsv in melanoma cell lines enhances the effect of BRAF inhibitor treatment. All in all, the data presented in this thesis elucidated a new era in the evaluation of melanoma patient prognosis and revealed new possibilities for more effective melanoma treatments.
Medicine, Faculty of
Medicine, Department of
Experimental Medicine, Division of
Graduate

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Rebecca, Vito William. "Potential Targeted Therapeutic Strategies for Overcoming Resistance in BRAF Wild Type Melanoma." Scholar Commons, 2014. http://scholarcommons.usf.edu/etd/5112.

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Melanoma manifests itself from the malignant transformation of melanocytes and represents the deadliest form of skin cancer, being responsible for the disproportionate majority of all skin cancer deaths. The 2002 discovery that 50% of all melanoma patients possess activating BRAF mutations ignited a significant paradigm shift in the way the melanoma field approached research and how patients were treated [1]. The era of targeted therapy had begun and with it came successful targeted BRAF inhibitor therapy regimens, which have accomplished improved clinical benefit (response rate, progression free survival, and overall survival) compared with treatment with chemotherapy in three phase III clinical trials [2]. Although there has been much success in the subgroup of patients whose melanomas harbor activating BRAF mutations, approximately 50% of all melanoma patients do not harbor BRAF mutations. This subgroup of melanoma is composed of ~15-20% of all patients with NRAS mutations and another ~25-30% of patients with neither BRAF nor NRAS mutations. Successful targeted treatment strategies are currently lacking for this subgroup of BRAF-wild type melanomas and therefore novel targeted therapeutic modalities are urgently needed. The work described in this dissertation sheds light on potential approaches for the treatment of BRAF wild type melanoma and will be split into three separate strategies. The first will focus upon the treatment of melanomas without BRAF or NRAS mutations (BRAF/NRAS wild type melanoma) and will expand upon a clinical observation where two melanoma patients were treated with an experimental combination of carboplatin and paclitaxel, with the addition of the AKT inhibitor MK-2206. We demonstrate that the inhibition of AKT significantly enhances the efficacy of chemotherapy in a reactive oxygen species (ROS) mediated fashion, and an induction of autophagy plays a cyto-protective role. The second story focuses upon the treatment of NRAS mutant melanomas by investigating resistance mechanisms to MEK inhibitor treatment. We discovered a MEKi-mediated induction of receptor tyrosine kinase (RTK) signaling to serve as a significant mechanism of escape for NRAS mutant melanomas treated chronically with the MEK inhibitor AZD6244, as well as the recently U.S. Food and Drug Administration (FDA) approved MEK inhibitor trametinib. Novel targeted therapy combinations were then added to overcome the escape from MEK inhibitor therapy. Co-targeting of the receptor tyrosine kinases AXL, PDGFR-β and c-MET with a pan-RTK inhibitor, as well as the mitogen-activated protein kinase (MAPK) pathway with a MEK inhibitor greatly enhanced treatment-induced apoptosis and inhibition of proliferation. The final strategy builds upon the observation that single agent MEK-inhibition is largely ineffective in the treatment of NRAS mutant melanomas. A recovery of MAPK pathway activity in response to MEK inhibition was established to play a significant role in escape of NRAS mutant cells from cell cycle arrest and apoptosis. The combination of a MEK inhibitor with the novel ERK inhibitor VTX-11e prevents the onset of resistant clones and enhances cytotoxicity of the NRAS mutant melanoma cells. This body of work establishes original targeted therapy combinations for the treatment of both NRAS mutant melanomas and BRAF/NRAS wild type melanomas. We propose future clinical investigation with these strategies in the treatment of BRAF wild type melanoma patients in hopes to further extend overall survival.

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Braune, Jan [Verfasser], and Nikolas von [Akademischer Betreuer] Bubnoff. "Zirkulierende Tumor DNA erlaubt Therapiemonitoring in BRAF und NRAS mutiertem malignem Melanom." Freiburg : Universität, 2021. http://d-nb.info/1231232560/34.

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Darp, Revati A. "Insights into the Role of Oncogenic BRAF in Tetraploidy and Melanoma Initiation." eScholarship@UMMS, 2021. https://escholarship.umassmed.edu/gsbs_diss/1129.

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Melanoma, the most lethal form of skin cancer, arises from altered cells in the melanocyte lineage, but the mechanisms by which these cells progress to melanoma are unknown. To understand the early cellular events that contribute to melanoma formation, we examined melanocytes in melanoma-prone zebrafish strains expressing BRAFV600E, the most common oncogenic form of the BRAF kinase that is mutated in nearly 50% of human melanomas. We found that, unlike wild-type melanocytes, melanocytes in transgenic BRAFV600Eanimals were binucleate and tetraploid. Furthermore, melanocytes in p53-deficient transgenic BRAFV600Eanimals exhibited 8N and greater DNA content, suggesting bypass of a p53-dependent arrest that stops cell cycle progression of tetraploid melanocytes. These data implicate tetraploids generated by increased BRAF pathway activity as contributors to melanoma initiation. Previous studies have used artificial means of generating tetraploids, raising the question of how these cells arise during actual tumor development. To gain insight into the mechanism by which BRAFV600E generates binucleate, tetraploid cells, we established an in vitro model by which such cells are generated following BRAFV600E expression. We demonstrate thatBRAFV600E-generated tetraploids arise via cytokinesis failure during mitosis due to reduced activity of the small GTPase RhoA. We also establish that oncogene-induced centrosome amplification in the G1/S phase of the cell cycle and subsequent increase in the activity of the small GTPase Rac1, partially contribute to this phenotype. These data are of significance as recent studies have shown that aneuploid progeny of tetraploid cells can be intermediates in tumor development, and deep sequencing data suggest that at least one third of melanomas and other solid tumors have undergone a whole genome doubling event during their progression. Taken together, our melanoma-prone zebrafish model and in vitro data suggest a role for BRAFV600E-inducedtetraploidy in the genesis of melanomas. To our knowledge, this is the first in vivo model showing spontaneous rise of tetraploid cells that can give rise to tumors. This novel role of the BRAF oncogene may contribute to tumorigenesis in a broader context.

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Yuan, Long. "Role of Reactive Oxygen Species and Therapeutic Implications in BRAF Mutant Melanoma." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595847645348909.

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Dinges, Hanns-Christian [Verfasser]. "Validierung eines Protokolls zur manuellen, mutationsspezifischen BRAF V600E Immunhistochemie / Hanns-Christian Dinges." Ulm : Universität Ulm, 2017. http://d-nb.info/1125528176/34.

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Bubolz, Anna-Maria [Verfasser]. "Potentielle klinische Implikationen von BRAF Mutationen in histiozytären Proliferationen / Anna-Maria Bubolz." Ulm : Universität Ulm, 2017. http://d-nb.info/1132713137/34.

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Anastasaki, Korina. "MAPK pathway : a role in development, disease and behaviour." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5955.

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Mutations in the RAS-RAF-MEK-ERK (MAPK) pathway give rise to a range of developmental disorders collectively referred to as the RASopathies. De novo germline mutations in patients suffering from these syndromes promote similar phenotypes, which include heart abnormalities, characteristic facial features, cutaneous malformations, gastrointestinal malfunctions, failure to thrive and a spectrum of mental retardation. Although many RASopathies patients show a propensity to develop early-onset benign and malignant tumours, Cardio-faciocutaneous (CFC) syndrome patients do not seem to share this predisposition, with the exception of an increased number of naevi. CFC syndrome is caused by mutations in BRAF, MEK1 or MEK2, with the majority of patients harbouring BRAF mutations. Intriguingly, both kinase-activating and kinase-impaired mutations have been identified in CFC patients. Here, I use the zebrafish system to address the activity of the CFC syndrome alleles and the MAPK pathway in a developmental context and test the potential of small molecule inhibitors to restore normal development. I established an assay for the activity of CFC, melanoma and engineered BRAF and MEK human mutated alleles in vivo. Using zebrafish as an animal model organism, a panel of 31 mutant and wild-type BRAF, MEK1 and MEK2 alleles were expressed in early zebrafish embryos to assess their role in development. Irrespective of the predicted kinase activity, all embryos expressing BRAF and MEK mutant alleles reproducibly manifested the cell movement phenotype during gastrulation. Consistent with aberrant fibroblast growth factor (FGF) signalling and defective gastrulation, in situ hybridisation against convergence-extension markers showed misregulated convergence-extension movement patterns in CFC zebrafish embryos. Finally, I performed whole embryo RNA expression microarrays to identify genes regulated downstream of the CFC mutations, and I discuss the potential for a possible link to some of the phenotypes associated with a CFC zebrafish model. I established that the CFC, BRAF and MEK mutant embryos are sensitive to inhibition of MEK signalling by small molecules. Importantly, a time-window of treatment was identified which was sufficient to restore normal gastrulation movements and to prevent the developmental side effects promoted by the inhibitors at later stages of development. In order to begin considering the therapeutic potential of small molecules in developmental disorders (at least in our model system), the effect of low concentrations of the inhibitors in the normal formation of diverse tissues was thoroughly examined during zebrafish development. From these studies, I identified a concentration of MEK inhibitor that could be administered in a continuous fashion to prevent CFC-associated cell movement defects during gastrulation, without additional later developmental defects. Finally, I addressed the role of MEK-ERK signalling in a specific behavioural phenotype in zebrafish. Many RASopathies patients suffer from mental retardation and experience learning and attention difficulties. Research in our laboratory has identified a novel zebrafish behaviour induced by enhanced cAMP signalling, where the zebrafish seek shaded areas in their environment and exhibit frequent defensive shoaling behaviour. I used western blotting to establish that enhanced cAMP signalling activates the MAPK signalling pathway and, in collaboration with members our laboratory, that this phenotype can be suppressed by administration of the PD325901 MEK inhibitor. While we do not yet know the effect of CFC syndrome mutations on this behaviour, we suggest that altered MEK-ERK signalling may underlie important features of vertebrate behaviour.

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Papadogeorgakis, Eftychios. "Development of malignant melanoma is dependent on a switch in Embryonic Transcription Factors orchestrated by the BRAF-MAPK pathway." Thesis, University of Leicester, 2013. http://hdl.handle.net/2381/28138.

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Reactivation of master regulators of epithelial to mesenchymal transition (MR-EMT) represents the molecular basis for tumour cell plasticity, malignant transformation and metastases. However, the current evidence on the specific role of MR-EMT in melanomagenesis has not been fully addressed. The purpose of this investigation was to assess the expression and regulation of these factors in malignant melanoma and to evaluate their prognostic and clinical significance. In vitro experiments indicated that a switch in MR-EMT protein expression ZEB2/SNAI2 to ZEB1/TWIST1 is RAS-RAF-MAPK signalling dependent. In addition, evidence supported a MR-EMT interactome, in which transcriptional repression of ZEB2 by Fra-1 resulted in upregulation of ZEB1, independently of miR-200 family. Further in vitro and immunohistochemical (IHC-P) analyses showed that E-cadherin and VDR protein levels were significantly reduced by the presence of ZEB1 in melanoma cells and archive tissues. Motility assays demonstrated that ZEB1 but not ZEB2 enhances cell migration. IHC-P analyses of ZEB2/SNAI2 (n=142/28) showed a statistically significant gradient of stronger staining at superficial sites compared to the deep sites in a select cohort of independent and matched melanoma tumour samples. In contrast, ZEB1 (n=142) and TWIST1 (n=133) showed higher staining in deep sites of primary melanomas and metastases. Trend analyses showed a significant MR-EMT switch in this progression series from high levels of ZEB2/SNAI2 in naevi towards high ZEB1/TWIST1 expression in melanomas. In primary melanomas these factors were also significant in Kaplan Meier survival curves and after two step cluster analysis the combined profile of ZEB1[superscript high]/TWIST1[superscript high]/ZEB2[superscript low] predicted the worse prognosis (P=0.001). Multivariate Cox regression analyses of IHC-P staining indicated that only the gain of ZEB1 (P<0.002, n=98) and superficial TWIST1 (P=0.012) were associated with poor metastasis-free survival and independent of breslow depth. In conclusion, the reversible switch between ZEB1/TWIST1 and ZEB2/SNAI2 is controlled by RAS-RAF-MAPK pathway activity and constitutes an independent factor of poor prognosis in patients with malignant melanoma.

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Curley, David. "Characterizing the Roles of BRAF, PTEN and Cdkn2a in Novel Mouse Models of Melanoma Formation and Progression." ScholarWorks @ UVM, 2008. http://scholarworks.uvm.edu/graddis/62.

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There will be an estimated 60,000 new cases and nearly 8000 deaths in the US this year due to malignant melanoma. People living in the US are expected to have a 1 in 71 lifetime risk of developing the disease. Activating mutations in BRAF occur in approximately 60% of melanomas and in 80% of benign melanocytic nevi. PTEN is a tumor suppressor that has been shown to be deleted or epigenetically silenced in approximately 30% of melanomas. Cdkn2a is a locus encoding 2 tumor suppressors in alternate reading frames that has been found to be mutated in up to 40% of familial melanomas and is near universally lost in human melanoma cell lines. We used these data to generate novel mouse models of metastatic melanoma involving an inducible Cre transgenic mouse (Tyr::CreER-T2). We demonstrate that Pten loss, Cdkn2a loss or Braf activation in isolation does not induce melanoma. In contrast, when Braf activation is combined with Pten loss, mice develop aggressive pigmented melanomas with 100% penetrance and a mean tumor free survival of 19.5 days. Melanocytic proliferation occurs immediately following induction with virtually no latency. Expansile metastases are observed in lymph nodes and isolated tumor cells are present in the lungs and brain. Both incipient and established melanomas are sensitive to the mTOR inhibitor rapamycin. Furthermore, mTORC1 signaling is prevented upon rapamycin treatment, but mTORC2, MAPK, and Akt signaling appear to be unaffected. Additionally, when Cdkn2a loss is combined with Braf activation, the mice develop a nevic phenotype with complete penetrance and stochastic progression to melanoma. Median melanoma free survival is 85.5 days and tumors are metastatic to lymph nodes in 100% of mice. These novel mouse models of melanoma will likely be useful in the study of the biology of metastasis, in tumor immunology, and in new models of preclinical testing.

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Wojciechowska, Sonia. "The conditional control of MITF reveals cellular subpopulations essential for melanoma survival and recurrence in new zebrafish models." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/29645.

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Melanoma is the most lethal type of skin cancer with over 132,000 cases occurring globally each year and continually rising incidence. BRAFV600E inhibitors have led to clinically significant improvements in outcomes for melanoma patients, yet many patients with metastatic melanoma rapidly succumb to the disease due to eventual chemoresistance or insensitivity to the drug. Thus, it is critical to identify new therapies that can act alone, or be combined with available treatments for enhanced efficacy and/or to overcome drug resistance. Evidence from human melanoma indicates that the melanocyte lineage is critical for melanoma survival and contributes to therapeutic resistance. MITF is a highly conserved “master melanocyte transcription factor” with a complex role in melanoma. Our lab has previously developed a temperature sensitive BRAFV600E mitfavc7 zebrafish melanoma model carrying a human oncogene and mitfavc7 splice site mutation that enables the conditional control of its endogenous activity by changes to water temperature. As part of my PhD project, I characterized and compared two new models developed since then: a very aggressive BRAFV600E mitfavc7p53M214K melanoma model with three driving mutations and a slower developing BRAF-independent mitfavc7p53M214K. I showed that the MITF activity is crucial for melanocyte survival in both models and that both mutated BRAF and p53 deficiency are oncogenic with low levels of MITF, and result in fish nevi and melanoma resembling the pathology of human disease. Both models are also relevant to a low-MITF subclass of human melanomas that emerged from a recent classification by The Cancer Genome Atlas Network. In addition, I established that, similarly to the BRAFV600Emitfavc7, complete inhibition of MITF activity leads to rapid tumour regression, but once its activity is restored the melanomas recur at the same site as the original tumour. I used histopathology studies and melanocyte lineage transgenes to identify and visualize subpopulations of cells remaining at the site of regression in these new zebrafish melanoma models. I hypothesised that these are the cells of origin for tumour recurrence (melanoma stem or progenitor cells), showed that some of them express a cancer stem cell marker aldehyde dehydrogenase, and attempted to target these subpopulations using 5-nitrofurans (a prodrug NFN1, shown previously by our lab to target ALDHhigh subpopulations in context of melanoma) in fish after melanoma regression. Finally, I also developed and described a new primary zebrafish melanoma cell line that I derived from one of these zebrafish tumours. This study is still in progress, but the cell line will be a useful tool for further investigation of these proposed melanoma progenitor cells in vitro, with potential applications for lineage tracing and transplantations.

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Steck, Mirjam [Verfasser], Luitpold [Akademischer Betreuer] Distel, and Luitpold [Gutachter] Distel. "Interaktion von BRAF-Inhibitoren und ionisierender Strahlung bei Behandlung von Fibroblasten und einer BRAF-mutierten und einer Wildtyp-Zelllinie des Malignen Melanoms / Mirjam Steck ; Gutachter: Luitpold Distel ; Betreuer: Luitpold Distel." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2020. http://d-nb.info/1220506028/34.

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48

Seitz-Alghrouz, Ruth Christin [Verfasser], and Paul [Akademischer Betreuer] Fisch. "BRAF V600E mutations in nevi and melanocytic tumors of uncertain malignant potential (MELTUMPs)." Freiburg : Universität, 2019. http://d-nb.info/1188195891/34.

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L'hôte, Valentin. "Senolytic drug discovery and mechanisms of action in BRAF-V600E oncogene-induced senescence." Thesis, université Paris-Saclay, 2022. http://www.theses.fr/2022UPASL042.

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En réponse à l'expression d'oncogène (tel que BRAF-V600E), à des traitements génotoxiques ou à d'autres stress, les cellules eucaryotes peuvent éviter l'apoptose et déclencher la sénescence. La sénescence est un destin cellulaire caractérisé par un arrêt prolifératif quasi-irréversible et une reprogrammation transcriptionnelle profonde, conduisant notamment à une sécrétion importante de facteurs inflammatoires collectivement appelés phénotype sécrétoire associé à la sénescence (SASP). En raison de l'augmentation de la demande sécrétoire et de stress chroniques, la protéostase peut être perturbée en sénescence. Comme elle limite la prolifération de cellules susceptibles de présenter un potentiel pré-néoplastique, la sénescence est un processus essentiel de suppression tumorale ; cependant, l'accumulation de cellules sénescentes au cours du vieillissement, dans des contextes pathologiques, ou après chimiothérapie ou radiothérapie, est préjudiciable et entraîne un dysfonctionnement tissulaire. Les sénolytiques sont des composés qui induisent sélectivement l'apoptose dans les cellules sénescentes tout en épargnant les cellules normales, et leur application thérapeutique s'est avérée une stratégie pharmacologique efficace dans différents contextes pathologiques où la sénescence joue un rôle moteur. Le but de ce projet était d'identifier de nouveaux composés sénolytiques, notamment dans la sénescence induite par BRAF-V600E, et de caractériser leurs mécanismes d'action, ajoutant ainsi à la compréhension de la régulation des voies de survie cellulaire en sénescence. Les cardioglycosides constituent une classe de composés qui ont été identifiés comme de puissants sénolytiques dans le criblage d'une chimiothèque de repositionnement. Nous avons montré que les cellules sénescentes BRAF-V600E étaient remarquablement sensibles à la sénolyse induite par les cardioglycosides. Nous avons démontré que les cellules sénescentes BRAF-V600E ont un flux autophagique accru, essentiel à leur survie, et que les cardioglycosides agissent comme sénolytiques en inhibant l'autophagie via la transduction du signal par la Na,K-ATPase. En conséquence, le blocage de l'autophagie par d'autres voies, comme avec la chloroquine, était également sénolytique. Pour mieux comprendre la régulation de l'autophagie et de la protéostase en sénescence et identifier de nouvelles cibles sénolytiques, nous avons ensuite évalué le stress du réticulum endoplasmique et la réponse aux protéines mal repliées (UPR) dans différents modèles de sénescence. En parallèle, nous avons criblé diverses chimiothèques, dans lesquelles nous avons identifié des sénolytiques potentiels ciblant différentes facettes de la protéostase. Notamment, nous avons découvert que le senseur de l'UPR Ire1 était régulé à la hausse en sénescence induite par l'expression d'oncogènes. Ire1 régule le destin cellulaire par plusieurs voies, et de nombreux composés qui modulent de manière différentielle son activité sont disponibles. Nous avons donc utilisé un panel de modulateurs d'Ire1 pour commencer à caractériser son rôle en sénescence, et établir de nouvelles stratégies sénolytiques. En résumé, nos résultats soulignent le potentiel sénolytique du ciblage de l'autophagie et de la protéostase dans la sénescence induite par l'expression d'oncogènes, et l'importance de caractériser en détails les mécanismes d'action des sénolytiques pour identifier de nouvelles cibles et voies de régulation
In response to oncogene expression (such as BRAF-V600E), genotoxic insults, or other stresses, eukaryotic cells can suppress apoptosis and enter senescence. Senescence is a cell fate characterized by a quasi-irreversible proliferative arrest and deep transcriptional reprogramming, notably leading to an important secretion of inflammatory factors collectively termed the senescence-associated secretory phenotype (SASP). Due to increased secretory demands and chronic stress, proteostasis may be challenged in senescence. As it limits the proliferation of cells possibly bearing pre-neoplastic potential, senescence is an essential tumor suppressing process; however, the accumulation of senescent cells during aging, in pathological contexts, or following chemotherapy or radiotherapy, is detrimental and leads to tissue dysfunction. Senolytics are drugs that selectively induce apoptosis in senescent cells while sparing normal cells, and their therapeutical application has proved a valuable pharmacological strategy in pathological contexts in which senescence plays a driving role. The aim of this project was to identify novel senolytic compounds, notably in BRAF-V600E-induced senescence, and to characterize their mechanisms of action, thereby adding to the understanding of cell survival pathways regulation in senescence. Cardioglycosides constitute a class of drugs that were identified as potent senolytics in the screen of a repurposing library. We showed that BRAF-V600E senescent cells were remarkably sensitive to senolysis induced by cardioglycosides. We demonstrated that BRAF-V600E senescent cells have a heightened autophagy flux that is essential to their survival, and that cardioglycosides acted as senolytics by inhibiting autophagy through Na,K-ATPase signal transduction. Accordingly, blocking autophagy through other routes such as with chloroquine was also senolytic. To gain insight into the regulation of autophagy and proteostasis in senescence and identify new senolytic targets, we then assessed endoplasmic reticulum stress and the unfolded protein response (UPR) in different senescence models. In parallel, we screened various chemical libraries, in which we identified potential senolytics targeting different facets of proteostasis. Interestingly, we found that UPR sensor Ire1 was upregulated in oncogene-induced senescence. Ire1 regulates cell fate through several pathways, and many small compounds that differentially modulate its activity are available. We thus employed a panel of Ire1 modulators to begin characterizing its role in senescence, and establish novel senolytic strategies. Collectively, our results highlight the senolytic potential of targeting autophagy and proteostasis in oncogene-induced senescence, and the importance of deciphering the mechanisms of action of senolytics to identify new targets and regulatory pathways

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50

Menzies, Alexander Maxwell. "The biology of BRAF-‐mutant melanoma and biomarkers of response to targeted therapy." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/13804.

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After decades of treatment failure, inhibition of the mitogen-activated protein kinase (MAPK) pathway with BRAF inhibitors, either as monotherapy or in combination with MEK inhibitors, have dramatically improved outcomes for patients with BRAF-mutant metastatic melanoma. Rapid and frequent responses occur, but clinical benefit is usually transient because of the emergence of drug resistance. The degree of response and duration of survival is highly variable, with no biomarkers to enable clinicians to predict individual patient response to therapy. This thesis explores the clinical phenotype of BRAF-mutant melanoma, the BRAF mutation status of tumours within metastatic patients, patterns of response and progression to MAPK inhibitors, clinical and molecular biomarkers that may predict response and survival with treatment, and the molecular mechanisms of resistance to treatment. Results show that subtypes of BRAF-mutant melanoma are clinically and biologically distinct, and while the BRAF mutation status within patients is homogeneous, tumour response and disease progression with MAPK inhibitors is markedly heterogeneous within patients. Serum lactate dehydrogenase is the most notable biomarker that predicts for response and survival. Mechanisms of acquired resistance are diverse and heterogeneous, both between and within progressing tumours, and most mechanisms reactivate the MAPK pathway.

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Dissertations / Theses on the topic 'BRAF35'

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