Tesi sul tema "Résistance aux thérapies"
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Geneste, Aline. "Tissu adipeux et résistance tumorale aux thérapies ciblées". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1115/document.
Targeted therapies as tyrosine kinase inhibitors permitted an improvement of breast cancer therapies by targeting HER2. However, resistance has been observed in obèse patients for lapatinib treatment.We reproduced the effect of resistance of breast cancer cells to laaptinib in presence of adipose tissue as observed for other therapies. Tumor cells overexpressing HER2 was partly resistant to lapatinib but also for other tyrosine kinase inhibitors when in contact with adipocyte-conditioned medium. By impnating human adipose tissue nad human tumors in mice, we were able to study rhe resistance of breast tumor cells in vivo.In order to elucidate the mechanism of such resistance, we exposed the adipocytes to several metabolism modulators. The lapatinib-induced cell cytotoxicity was lower for the tumor cells exposed to the conditioned medium from adipocytes earlier exposed to alpha blockers than to the conditioned medium from adipocytes alone. In the same manner, the toxicity was lower for the agonists of alpha-adrenergic receptors , for beta-blockers and for the lipolysis inhibitors. At the opposite, the cytotoxicity was enhanced for tumor cells in contact with the conditioned medium of adipocytes exposed to the agonists of beta adrenergic receptors.At the tumor cell level, the laaptinib-induced cell cycle arrest was reduced for the tumor cells exposed to the conditioned medium regarding the G0/G1 phase. That was verified by the study of the expression of genes involved in the cell cycle progression
Lhuissier, Eva. "Chondrosarcome : mécanismes de résistance aux traitements conventionnels et thérapies innovantes". Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC407/document.
Chondrosarcomas are bone malignant tumors, considered as radio- and chemo-resistant, due to their hypoxic environment. In this context, this study aimed to better understand the role of hypoxia in the resistance of these tumors to chemotherapy (cisplatin) and radiotherapy (X-rays) and to identify new therapeutic strategies to re-sensitize chondrosarcomas by epigenetic targeting of H3K27 methylation. First, we showed that, contrary to what is commonly accepted, hypoxia has differential effect on cisplatin or X-ray sensitivity in chondrosarcomas, while it increases cisplatin resistance and X-ray sensitivity only in one cell line. Secondly, 3-deazaneplanocin A (DZNep) induces apoptosis in these tumors by a mechanism independent of H3K27 methylation and its methylase EZH2 and seems to act through the Rhoβ / EGFR pathway. However, it causes side effects on male fertility. In addition, its association with cisplatin potentiates its toxic effects on chondrosarcomas. The GSK-J4, on the other hand, decreases cell growth and its association with cisplatin increases this effect.This study highlights that chondrosarcomas use different cellular regulation mechanisms, showing the importance of conducting studies on several cell lines in order to better predict the response to treatments. In addition, these studies demonstrate the anti-tumoral properties of DZNep and GSK-J4 in the treatment of these tumors
Kammerer-Jacquet, Solène-Florence. "Carcinome à cellules claires du rein : phénotype métastatique et résistance aux thérapies ciblées". Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1B038.
Clear cell renal cell carcinoma (ccRCC) is the most common kidney cancer. It is characterized by frequent inactivation of the tumor suppressor gene VHL found in 70% of tumors leading to the transcription of HIF transcription factor target genes such as VEGF. This is an aggressive tumor with 50% of metastatic patients. Sunitinib, an inhibitor of receptor tyrosine kinase antiangiogenic, is currently the most used in 1st line despite 30% of patients who progress quickly. The advent of a new anti-angiogenic targeting MET (cabozantinib) and immunomodulators (anti-PD-1 antibody, nivolumab) makes crucial discovery of predictors of response to treatment. In the first part, we studied a retrospective study of 98 consecutive ccRCC. We assessed complete VHL status and correlated it with the expression of PD-L1. Moreover, while the prognosis is different between ccRCC synchronous metastatic and metachronous, their phenotype have never been compared. In this purpose, we performed an analysis of the main pathological prognostic factors, immunohistochemical markers (CAIX, VEGF, PAR3, PD-1 and PD-L1) and molecular (VHL status: deletion, mutation and promoter methylation) correlated with specific survival. We demonstrated that non-inactivated VHL tumors (niVHL) were associated with the presence of synchronous metastases, sarcomatoid component, a dense lymphocytic infiltrate, an overexpression of VEGF, an expression of PD-L1 and a poor prognosis. We also compared the phenotypes of metachronous and synchronous metastatic ccRCC. The first ones were associated with sarcomatoid component, cytoplasmic expression of PAR-3 overexpression VEGFA and niVHL status and a poor prognosis even from the diagnosis of metastases. In the second part, we studied a retrospective study of 90 consecutive metastatic ccRCC treated with first line sunitinib to identify predictors of response or resistance. We used the same techniques as above plus the MET status (mutation in Next-Generation sequencing and expression by IHC). Patients were classified as primary-refractory, intermediate and long-term responders depending on the duration of their response as assessed by radiological criteria (RECIST). We also characterized the genetic profile of 73 ccRCC of this series by CGH array for which we had frozen tumor. Primary refractory patients often had poor prognosis (Heng criteria), liver metastases, infiltration of the hilar fat. Cytogenetically, their tumors had many more genetic alterations, both gains as losses. These recurrent alterations were gains of 5p, 7p, 8q22.1-qter and loss of 6q21-q25.3 region. The multivariate Cox model highlighted four independent factors: the score of Heng, liver metastases, infiltration of the hilar fat and gain of 8q which integrated into a prognostic nomogram had a c-index of 0.74 for survival progression-free survival and 0.77 for overall survival. In conclusion, our study identified a subtype of ccRCC with a poor prognosis with niVHL status that should be explored at the genomic level. Furthermore, we showed a phenotype difference between ccRCC synchronous and metachronous metastatic patients whereas their care is currently the same. Finally we have identified a prognostic nomogram in metastatic ccRCC treated with sunitinib in the first line. This nomogram if confirmed by a larger prospective study could have a significant clinical impact in the selection of patients most likely to benefit from anti-angiogenic therapy
Delmas, Audrey. "Rôle de la petite GTPase RhoB dans la résistance des mélanomes aux thérapies ciblées". Toulouse 3, 2013. http://thesesups.ups-tlse.fr/2465/.
Melanoma treatment recently met a breakthrough with the approval of Vemurafenib, a BRAFV600E inhibitor. However, its efficiency is limited as patients rapidly develop resistances still misunderstood. This project reveals an original pathway involved in resistance to Vemurafenib and also to MEK inhibitors, another new therapeutic class approved in melanoma. In response to Ras/Raf/MEK/ERK pathway inhibition by B-Raf or MEK inhibitors, c-Jun is overexpressed and activated leading to RhoB overexpression by an iCCAAT box-dependent transcriptional activation. Induced RhoB favors cell survival in response to these inhibitors in an AKT-dependent manner. Inhibition of the c-Jun/RhoB/AKT pathway with siRNA or AKT inhibitors potently increases B-Raf and MEK inhibitors efficiency through apoptosis triggering. In conclusion, we identified for the first time the involvement of the c-Jun/RhoB/AKT pathway in Vemurafenib resistance and demonstrated the synergism of the Vemuranib/AKT inhibitor association. In fact, we demonstrated, at molecular level, the relevance of current clinical evaluation of B-Raf/MEK and AKT inhibitors association
Hatat, Anne-Sophie. "Epissage Alternatif d'ATG16L1b : un rôle dans l'échappement des tumeurs pulmonaires aux thérapies anti-EGFR". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAV027/document.
Identifying what is a driver oncogene and developping small molecules that are able to targetits activity led to drastic changes in NSCLC treatments. EGFR is a transmembrane receptorwith Tyrosine Kinase (TK) activity allowing signal transmission from the environment towardsthe inner of the cell by signaling pathways activation. Among those signaling pathways arefound survival and proliferation pathways. Activating mutations make EGFR a driver onco-gene, which was the first protein to be identified as such. Hence numerous chemical compoundtargeting mutated EGFR (EGFR-TKI, gefitinib) have been developped. Their use in clinicsrepresent a huge improvement for patients care. However resistance mechanisms ultimatelyoccur. Transcriptomic analyses of acquired resistant models to EGFR-TKI have shown thattheir RNA transcripts expression is abnormal. Moreover results from the team have demons-trated that SR proteins (splicing factor) expression is deregulated in NSCLC. Based on thoseresults we hypothesized that SRSF2 mediated alternative splicing of mRNA could be involvedin resistance mechanims acquired by lung carcinoma in response to EGFR-TKIThe lab developped resistant clones by chronic exposure to gefitinib of EGFR mutated lungadenocarcinoma cellular models.We first observed the accumulation of the expression of SRSF2 protein in resistant clonescompared to the sensitive cell line. Secondly, sensitivity to gefitinib induced apoptosis of twoclones was resored when neutralising SRSF2. A RNA-seq analysis led us to identify Atg16L1 aspotentially being involved in the SRSF2-mediated sensitization to gefitinib-induced apoptosis.SRSF2 neutralisation modulates Atg16L1 splicing in response to gefitinib. Neutralisation ofExon 8 containing transcripts of Atg16L1 sensitizes resistant clones to gefitinib induced apop-tosis. This alternative splicing switch modulates autophagic activity of the cells in reponseto gefitinib. We have shown that exon8 containing transcripts favor autophagy inhibition inreponse to gefitinib. This work emphasize the role of Atg16L1 alternative splicing switch ofexon8 in autophagy inhibition and its correlation with a resistant phenotype in response toEGFR-TKI. SRSF2 may participate in the modulation of this alternative splicing switch inreponse to gefitinib
Guérard, Marie. "Signalisation nucléaire de l'IGF-1R et résistance aux thérapies anti-EGFR dans les cancers du poumon". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAV085/document.
Responsible of 1.6 million deaths each year worldwide, lung cancer is today the leading cause of cancer mortality in the world. Non-small-cell lung cancers account for about 85% of lung cancer and have a very bad prognosis (5-year survival rate inferior to 10%). EGFR-TKI (EGFR tyrosine kinase inhibitors, gefitinib) are a real medical advance for lung cancers treatment. However, these treatments are efficient in a small subgroup of patients. So, one of the current issues is to identify primary resistance mechanisms involved in tumors.Tyrosine kinase receptors (RTK) activate intracellular signaling pathways from the plasma membrane. These last years, a nuclear translocation of the RTK was shown. Recent works suggest that RTK nuclear signaling could contribute to tumors resistance in response to anti-cancerous therapies.In our team, it was shown that activation of IGF-1R signaling is associated with lung adenocarcinoma progression and that gefitinib induces IGF-1R nuclear accumulation in a mucinous adenocarcinoma cell line. On the basis of these results, we hypothesize that nuclear IGF-1R could play a role in the resistance of mucinous lung adenocarcinoma to EGFR-TKI.Our results indicate that more than 70% lung adenocarcinoma tumors present a positive IGF-1R nuclear staining. Thanks to EGFR-TKI-resistant cell lines, we show that gefitinib induces the nuclear accumulation of IGF-1R in mucinous adenocarcinoma. This nuclear translocation involves clathrin-mediated endocytosis and a complex between IGF-1R, importin β1 and pro-amphiregulin. Amphiregulin silencing prevents IGF-1R nuclear translocation in response to gefitinib and restores gefitinib-induced apoptosis in vitro and in vivo. Our whole results identify that IGF-1R intracellular trafficking is a new component of response to EGFR-TKI and strongly suggest that a nuclear IGF-1R/amphiregulin signaling contributes to mucinous lung adenocarcinoma progression in response to EGFR-TKI
Blandin, Anne-Florence. "Rôle de l'intégrine α5β1 dans la biologie du glioblastome et dans la résistance aux thérapies anti-EGFR". Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAJ066/document.
Glioblastoma multiforme (GBM) is the most common primary brain tumor. Alteration of the EGFR pathway and high invasive potential are hallmarks of GBM. Unfortunately, trials using anti-EGFR therapies for the treatment of GBM reveal limited efficacy. We previously showed that overexpression of the fibronectin receptor, α5β1 integrin, is associated with a poor prognosis for patients and is responsible for chemoresistance to temodal. Integrins can cross-talk with growth factor receptors and amplified their oncogenic activity. Here, we sought to determine the potential role of α5 integrin in resistance to anti-EGFR therapy. Using U87 GBM cell line, we first confirmed that fibronectin-mediated integrin activation potentiated EGFR signaling. Loss of α5 integrin expression sensitized U87 cells to anti-EGFR drugs (cetuximab, gefitinib) in soft agar clonogenic assay. α5 expression can trigger resistance to both drugs on cell migration. To go further, we developed a new assay based on the quantification of cell evasion from tumor spheroids. α5 depletion increased U87 cell sensitivity to gefitinib and erlotinib, 2 EGFR-selective reversible TKI, but had not effect on lapatinib efficacy, an irreversible TKI that target EGFR, ErbB2, ErbB3 and ErbB4. Confocal microscopy revealed a strong impact of gefitinib on EGFR and integrin endocytosis. These results suggested that α5 expression may trigger resistance to TKI either by activating ErbB pathways or by controlling EGFR membrane trafficking. We also showed that to promote cell adhesion, α5 integrin stimulated fibronectin fibrillogenesis. As cells moved away from the spheroids, α5 became strictly engaged in cell-substratum adhesion sites where it recruited activated FAK. Our work highlights the pivotal role of fibronectin/α5β1 integrin in invasivity of GBM and resistance to anti-EGFR drugs
Diazzi, Serena. "Le cluster pro-fibrotique miR-143/145 favorise la plasticité phénotypique associée à la résistance des mélanomes aux thérapies ciblées". Thesis, Université Côte d'Azur, 2021. http://theses.univ-cotedazur.fr/2021COAZ6006.
Because of its intrinsic plasticity and resistance to treatment, melanoma is one of the most aggressive cancers. Due to the MAPK pathway hyperactivation, targeted therapies counteracting this signaling cascade are efficient in most patients harboring BRAFV600E metastatic melanoma. However, innate and acquired resistances constitute major therapeutic challenges. Acquired resistance to MAPK-targeted therapies arises from de novo genetic lesions and non-genetic events such as transcriptional reprogramming and epigenetic changes. Upon MAPK inhibitors exposure, melanoma cells assume functionally different phenotypic states defined by master transcription factors differential activity and fixed by epigenetic events. Among them, the emergence of a poorly differentiated cell state is strongly associated with resistance acquisition and tumor recurrence. Our team has previously shown that melanoma cells switching to a dedifferentiated phenotype in response to MAPK-targeted therapies display features of cancer-associated fibroblasts (CAFs) like extracellular matrix (ECM) remodeling and markers observed in fibrotic diseases, allowing them to generate a drug tolerant microenvironment.This fibrotic state is characterized in vitro and in vivo by increased deposition and altered ECM organization associated with a mechanophenotype regulated by the mechanotransducers YAP and MRTFA. However, post-transcriptional signaling networks that underpin this mesenchymal-like phenotype are still unknown and effective therapeutic treatments to overcome MAPK-targeted therapy resistance are missing. Given the tumorigenic role of ECM in cancer progression and resistance, therapies aimed at “normalizing” the tumorigenic ECM represent promising strategies to overcome non-genetic resistance to MAPK inhibitors. Based on the role of miRNAs in post-transcriptional regulation, I focused on the characterization of a pool of miRNAs, defined as “FibromiRs,” which have been shown to participate in the onset and progression of fibrotic diseases. Their crucial role in the fibrogenic process and the possibility to therapeutically manipulate them make them promising druggable targets to prevent the onset of resistance to MAPK-targeted therapies in melanoma. Starting from a screening designed to compare the expression of “FibromiRs” in MAPK inhibitors resistant mesenchymal melanoma cells compared to therapy-naive parental cells, we have identified the profibrotic miR-143/145 cluster as overexpressed in mesenchymal resistant cells. We then explored the profibrotic function of miR-143/145 cluster in the mesenchymal-like resistant cell state and melanoma phenotypic plasticity. First, we analysed the regulation of miR-143 and miR-145 in melanoma, identifying a negative regulation of the MAPK pathway on its expression and the involvement of signaling pathways typical of the mesenchymal resistant state, such as TGFβ and PDGF signaling, in the activation of their expression. Next, we investigated the function of the cluster in the context of adaptive and acquired resistance, showing its contribution in ECM reprogramming, activation of mechanotransduction pathways, and in driving the switch from a differentiated proliferative phenotype to a dedifferentiated invasive one with decreased sensitivity to MAPK inhibition. We characterized its mechanism of action, identifying FSCN1 as a key target gene of both mature miR-143 and miR-145 in the acquisition of the mesenchymal invasive phenotype. Finally, we tested the cluster as a potential therapeutic target in vitro and in vivo through antisense oligonucleotide-mediated inhibition of its expression or pharmacological modulation combined with MAPK inhibitors administration. Overall, this work highlights the importance of a FibromiR cluster in the acquisition of a dedifferentiated phenotype resistant to MAPK-targeted therapies and proposes new therapeutic strategies based on the inhibition of FibromiRs to overcome such resistance mechanism
Ben, Jouira Rania. "Implication de la matrice extracellulaire tumorale dans la transition phénotypique et la résistance aux thérapies ciblées du mélanome". Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4140.
Cutaneous melanoma remains one of the most challenging and difficult cancers to treat because of its high plasticity, metastatic potential and resistance to treatment. New therapies targeting oncogenic BRAFV600E mutation have shown remarkable clinical efficacy. However, drug resistance invariably develops. Thus, the need for improving existing therapies remains critical. Recent studies have indicated that tumor resistance arises from the tumor microenvironment in which the extracellular matrix (ECM) is a determinant factor. Here, we found that BRAF inhibitor (BRAFi)-resistant melanoma cells, but not BRAFi-sensitive cells display an increased mechanosensitivity associated with a capacity to produce and remodel a 3D ECM displaying increased levels of matrix proteins such as fibronectin (FN) and collagen fibers. Interestingly, our results show that this 3D ECM is able to protect therapy-sensitive cells from the anti-proliferative effects of MAPKi. In addition, short exposures of naive melanoma cells to MAPKi augment matrix proteins production and assembly in vitro and in vivo. This 3D ECM also promotes drug tolerance within BRAFi sensitive cells. In conclusion, our results suggest that a subset of resistance to MAPK targeted therapies is associated with the production by melanoma cells of a pathological fibrotic matrisome that may affect cell behavior and therapeutic response
Combès, Eve. "Mise en évidence d’intéractions létales par criblage phénotypique dans le contexte de la résistance aux thérapies du cancer colorectal". Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT134/document.
Today, treatments for metastatic colorectal cancer have evolved through the combination of conventional chemotherapy 5-FU, oxaliplatin and / or Irinotecan and targeted therapies directed against the EGF receptor or VEGF. Despite an improved survival rate through the combination of these drugs, innate and acquired resistance to treatment is a common cause of therapeutic failure.In order to discover new therapeutic targets we carried out several phenotypic screenings using cellular resistance models acquired to chemotherapies (oxaliplatin and irinotecan) generated in the laboratory as well as the HCT116 line which exhibits an innate resistance to anti-EGFR therapies (cetuximab , panitumumab, Erlotinib). The ultimate goal of this project is to reveal genes, whose inhibition restores sensitivity to one of these treatments, thus displaying a lethal interaction with the drug.Once the kinases potentially involved in resistance to CCR therapies identified, specific inhibition by shRNA and / or a specific inhibitor was performed to confirm the potential therapeutic targets and / or biomarkers for response to treatments. The most promising target, identified as a determinant of resistance to oxaliplatin is the ATR protein (Ataxia-telangiectasia mutated and rad3 related). A protein that plays a key role in DNA repair and is activated in response to the presence of persistent single stranded DNA (ssDNA) or replicative stress, which can be generated by certain anti-cancer therapies.The inhibition of ATR via its pharmacological inhibitor VE-822 (VX-970) combined with oxaliplatin was then studied by the use of cytotoxic tests supplemented by an additivity study. Thus, we demonstrated that the inhibition of ATR combined with oxaliplatin leads to a strong synergy in the HCT116-R1 cell line in both 2D and 3D. This effect is also found in other oxaliplatin resistant clonal lines (HCT116-R2, SW48-R) as well as in the cell lines originating from them (HCT116, SW48).We have also shown that the synergistic effect of oxaliplatin and VE-822 in the HCT116-R1 line is accompanied by an increase in the presence of single-stranded DNA followed by numerous double-stranded DNA breaks, stopping proliferation and inducing apoptosis. The occurrence of this damage to DNA is also correlated with activation of the ATM pathway, p53 and inhibition of CDK2 activity. Moreover, in vitro the double treatment causes an induction of the molecular signals triggering the immunogenic cell death equivalent or superior to the treatments by oxaliplatin alone.Finally, the combination of oxaliplatin + VE-822 is also effective in vivo in immunodeficient mice xenografted with HCT116-R1 cells as well as in immunologically competent mice with a higher synergistic effect indicating that immune death (ICD ) is part of the mechanism of this combination of drugs.In conclusion, all these data confirm the interest of phenotypic screening in the discovery of new therapeutic targets by demonstrating for the first time the functional role of ATR in sensitivity to oxaliplatin
Kužet, Sanya-Eduarda. "Étude du rôle de la rigidité matricielle dans la résistance des cellules de carcinomes squameux aux thérapies anti-cancéreuses". Thesis, Université Côte d'Azur (ComUE), 2019. http://www.theses.fr/2019AZUR4010.
Resistance to epidermal growth factor receptor (EGFR) targeted therapy triggered by the tumor niche in head and neck squamous cell carcinoma (HNSCC) represents a challenge in research and in clinics. Despite the fact that over 15% of HNSCC overexpress EGFR, HNSCC are refractory to EGFR Tyrosine Kinase Inhibitors (TKIs) targeted therapy and yet the molecular and cellular mechanisms of EGFR-TKIs resistance in HNSCC are unknown. The tumor niche plays an important role in conventional chemotherapeutic resistance. Cancer associated fibroblasts (CAFs), the most prominent stromal cell in tumor niche, participate in this process. Notably, CAFs are responsible for tumor tissue fibrosis an excessive extracellular matrix (ECM) remodeling that increases matrix stiffness. In carcinoma cells, adhesion to stiff substrate triggers mechano-dependent intracellular signaling pathways that favor tumor resistance to conventional chemotherapies. My work demonstrates that ECM stiffening is responsible for a significant increase of squamous cell carcinoma (SCC) survival upon the treatment with EGFR TKIs, conventional chemotherapies and combination of both. Over 60% more cells survive treatment with the gefitinib EGFR TKI compared to cells plated on soft matrix. Same effect was observed on matrix derived from CAFs that is known to be stiffer compared to the one derived from fibroblasts isolated from normal skin. Further analysis revealed an induction of partial epidermal-to-mesenchymal transition (EMT) in cells plated on rigid matrices. EMT is know to play a role in resistance of cancer cells to treatments, and I have demonstrated that downregulation of know transcriptional factors involved in EMT leads to an increase of cell susceptibility to EGFR TKI when plated on stiff matrix. To understand in more detail what drives the resistance of SCC cells when plated on stiff we conduced an RNA sequencing. RNA sequencing of SCC12 cells plated on soft and stiff matrix revealed AXL as main driver of EGFR TKI resistance in HNSCC. I was able to demonstrated that inhibiting AXL in SCC cells, lying on stiff matrices, reverts the EGFR TKI resistance triggered by the tumor niche. Moreover, I show in 3D cell culture the importance of combining AXL and EGFR TKI in treatment of SCCs. Our overall goal was to identify novel therapeutic targets with reduced resistance opportunity. Finally, research presented in this manuscript carries potential in establishing a prediction biomarker to the response of HNSCCs and other cancers to EGFR TKIs
Guiho, Romain. "Thérapies impliquant la voie de TRAIL dans les tumeurs osseuses pédiatriques : mécanismes de résistance et approches précliniques pour une (re-)sensibilisation". Nantes, 2015. https://archive.bu.univ-nantes.fr/pollux/show/show?id=317c45e6-23f6-4b90-9560-60f354209ad8.
Osteosarcoma (OS) and Ewing's sarcoma (EWS) are the two most common pediatric bone tumors. Despite therapeutic advances, in the case of a metastatic tumor or a resistant to chemotherapy, the survival rate at five years is 20%. Pro-apoptotic cytokine TNF-Related Apoptosis Inducing Ligand (TRAIL) can selectively kill tumor cells and could be a new therapeutic approach for these high-risk patients. However, the study of many cell lines and several xenograft models in nude mice for TRAIL sensitivity, showed the existence of resistance phenomena to the TRAIL pro-apoptotic pathway, but also the ability of tumor cells to favor a second TRAIL signaling pathway, inducing survival and proliferation. The aim of our study is to identify molecular mechanisms involved in TRAIL resistance in these diseases, to offer sensitization strategies, with in vitro and in vivo approaches. Our sensitization strategies are based on two hypothesis: 1) the negative role of bone tumor microenvironment on TRAIL sensitivity, with the use of potentially sensitizing molecules targeting the microenvironment (chemotherapy agents, bisphosphonates. . . ). 2) The use of new activation tools of TRAIL pathway, with greater ability to induce surface receptors clusterization, thus promoting the proapoptotic pathway
Recondo, Gonzalo. "Resistance Mechanisms to ALK Tyrosine Kinase Inhibitors (TKIs) in NSCLC". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS248/document.
The molecular study and classification of lung adenocarcinomas has led to the development of selective targeted therapies aiming to improve disease control and survival in patients. The anaplastic lymphoma kinase (ALK) is a tyrosine kinase receptor from the insulin tyrosine kinase receptor family, with a physiologic role in neural development. Gene rearrangements involving the ALK kinase domain occur in ~3-6% of patients with lung adenocarcinoma. The fusion protein dimerizes leading to transactivation of the ALK kinase domain in a ligand-independent and constitutive manner. Lorlatinib is a third generation ALK inhibitor with high potency and selectivity for this kinase in vitro and in vivo, and elevated penetrance in the central nervous system. Lorlatinib can overcome resistance mediated by over 16 secondary kinase domain mutations occurring in 13 residues upon progression to first - and second - generation ALK TKI. In addition, treatment with lorlatinib is effective for patients who have been previously treated with a first and a second generation or a second generation ALK TKI upfront and is currently approved for this indication. The full spectrum of biological mechanisms driving lorlatinib resistance in patients remains to be elucidated. It has been recently reported that the sequential acquisition of two or more mutations in the kinase domain, also referred as compound mutations, is responsible for disease progression in about 35% of patients treated with lorlatinib, mainly by impairing its binding to the ALK kinase domain. However, the effect of these compound mutations on the sensitivity to the repertoire of ALK inhibitors can vary, and other resistance mechanisms occurring in most patients are unknown. My PhD thesis aimed at exploring resistance to lorlatinib in patients with ALK-rearranged lung cancer through spatial and temporal tumor biopsies and development of patient-derived models. Within the institutional MATCH-R study (NCT02517892), we performed high-throughput whole exome, RNA and targeted next-generation sequencing, together with plasma sequencing to identify putative genomic and bypass mechanisms of resistance. We developed patient-derived cell lines and characterized novel mechanisms of resistance and personalized treatment strategies in vitro and in vivo. We characterized three mechanisms of resistance in four patients with paired biopsies. We studied the induction of epithelial-mesenchymal transition (EMT) by SRC activation in a patient-derived cell line exposed to lorlatinib. Mesenchymal cells were sensitive to combined SRC and ALK co-inhibition, showing that even in the presence of an aggressive and challenging phenotype, combination strategies can overcome ALK resistance. We identified two novel ALK kinase domain compound mutations, F1174L/G1202R, C1156Y/G1269A, occurring in two patients treated with lorlatinib. We developed Ba/F3 cell models harboring single and compound mutations to study the differential effect of these mutations on lorlatinib resistance. Finally, we characterized a novel mechanism of resistance caused by NF2 loss of function at the time of lorlatinib progression through the development of patients derived PDX and cell lines, and in vitro validation of NF2 knock-out with CRISPR/CAS9 gene editing. Downstream activation of mTOR was found to drive lorlatinib resistance by NF2 loss of function and was overcome by providing treatment with mTOR inhibitors.This study shows that mechanisms of resistance to lorlatinib are more diverse and complex than anticipated. Our findings also emphasize how longitudinal studies of tumor dynamics allow deciphering TKI resistance and identifying reversing strategies
Astorgues-Xerri, Lucile. "Rôle de la galectine-1 et de la transition épithélio-mésenchymateuse dans la sensibilité et la résistance aux thérapies ciblées anticancéreuses". Paris 7, 2011. http://www.theses.fr/2011PA077129.
Deciphering mechanism of resistance to anticancer targeted therapies represent a crucial challenge of medical progress for the identification of future therapeutic targets. In our panel of tumor cell lines, résistance to PKCs inhibitors is mainly associated with epithelial to mesenchymal transition. Indeed, resistant cells show an increase in mesenchymal markers concomitant with a decrease in epithelial markers. Our findings point out endothelin-1 and activating K-Ras mutation as the molecular factors responsible of PEP005 and enzastaurin resistance, respectively. PTX-008 is a compound aimed to target galectin-1, a lectin implicated in tumor proliferation and metastatic dissemination. PTX-008 inhibits the proliferation of tumor cells with épithelial phenotype and low levels of galectin-1. In thé PTX-008-sensitive head and neck cell line, PTX-008 decreases galectin-1 expression and blocks PI3K/AKT and MAPK pathways. In xenografts, PTX-008 treatment inhibits tumor growth, angiogenesis and metastatic dissemination. In combination, PTX-008 shows synergistic effects with another antiangiogenic agent as sunitinib, and potentiates the effects of several classical cytotoxic compound used in clinical practice. Moreover, a cell line PTX-008-resistant has been developed in our lab, which displays a mesenchymal phenotype and a marked galectin-1 expression decrease. Altogether, our results may contribute to optimize future selection of patients candidate to targeted therapies, and validate galectin-1 as a promising new target for innovant anticancer approaches
Long-Mira, Élodie. "Identification de biomarqueurs tissulaires et sanguins impliqués dans la progression, la réponse et la résistance aux thérapies ciblées des mélanomes cutanés". Thesis, Université Côte d'Azur (ComUE), 2016. http://www.theses.fr/2016AZUR4129.
Background: Knowledge of the BRAFV600E status is mandatory in metastatic melanoma patients (MMP). Molecular biology is currently the gold standard method for status assessment. The aim of this work was to assess and compare several methods of molecular biology and immunohistochemistry (IHC) in tissue and blood (cell-free circulating tumor DNA, circulating tumor cell (CTC)) to identify predictive biomarkers of response or resistance to targeted treatment. Results: We showed that BRAFV600 IHC could be a substitute for molecular biology in the initial assessment of the BRAFV600E status in MPP. We also found that the presence of circulating tumor cell detetcted by a cytomorphological approach ISET (Isolation by Size of Epithelial Tumor Cell – Rarecells Diagnostics, Paris, France) in MMP is an independent predictor of shorter survival. Then, in a monocentric study conducted at the University of Nice Hospital, we evaluated a novel and fully automated CE-IVD PCR-based system (IdyllaTM, Biocartis, Mechelen, Belgium) for plasmatic BRAF and NRAS mutation detection. We showed that this technology is highly sensitive and specific and provide promising potential to assess tumor progression, identify targets for therapy, and evaluate clinical response to treatment. In conclusion, identification of tissue and blood biomarkers with these technologies allow a quick turnaround-time to BRAF/NRAS diagnosis and improve monitoring of treatment response and development of resistance in metastatic melanoma patients
Lheureux-Thelliez, Stéphanie. "Evaluation préclinique de thérapies dirigées contre Bcl-xL et Mcl-1 dans les cancers de l'ovaire : focus sur les molécules BH3-mimétiques". Caen, 2013. http://www.theses.fr/2013CAEN4076.
Ovarian cancers are addicted to the anti-apoptotic proteins Bcl-xL and Mcl-1. In this context, the BH3-mimetic ABT 737 molecule appears therapeutically promising as it inhibits Bcl xL, although its activity in vitro is conditioned by Mcl-1 inactivation. In vitro, ABT-737 as a single agent was ineffective at promoting cell death in the four cell lines tested. Platinum compounds sensitize to ABT-737 by dose-dependently decreasing Mcl-1 expression or by increasing the expression of pro-apoptotic BH3-only proteins Noxa and, to a lower extent, Bim. Surprisingly in the ex vivo study on human ovarian cancer, we demonstrated that ABT-737 induced massive apoptotic cell death as a single agent and that its efficacy was not significantly improved when combined with carboplatin. Bim expression at baseline appears as a relevant biomarker that could be easily used in clinical practice for the selection of ovarian cancer patients in the development of a clinical trial using ABT-263. We also studied in vivo the interest of targeting the PI3K/Akt/mTOR pathway to overcome chemoresistance in ovarian cancer. BEZ235, a dual PI3K/mTOR inhibitor, induced a marked and homogeneous decrease in FDG uptake in a cisplatin-resistant ovarian cancer model, which was correlated to a significant decrease in cell proliferation and to a significant PI3K/mTOR pathways inhibition. Four days following treatment cessation, tumor recovery was observed and correlated to FDG SA-PET/CT findings. These data suggest that FDG PET could be of use for therapy monitoring of PI3K/mTOR inhibitors
Berestjuk, Ilona. "Rôle de la matrice extracellulaire et des récepteurs à domaine discoïdine, DDR1 et DDR2, dans la résistance des cellules de mélanome aux thérapies ciblées". Thesis, Université Côte d'Azur (ComUE), 2019. http://www.theses.fr/2019AZUR6029.
Melanoma is a very aggressive skin cancer because of its intratumoral heterogeneity, high metastatic potential and resistance to treatment. Driver mutations mainly affect the BRAF and NRAS genes leading to the constitutive activation of the MAP kinase pathway (MAPK). New therapeutic options such as targeted therapies that combine BRAF (Vemurafenib) and MEK (Trametinib) inhibitors as well as immunotherapies are available, but these treatments only benefit certain patients and their use is limited because of the emergence of resistance. It is therefore essential to better understand the escape mechanisms in response to targeted therapies, in order to improve their effectiveness.The ability of cancer cells to resist treatment depends in part, on their ability to adapt to the tumour microenvironment. Within the primary tumour and various metastatic niches, the cancer cell interacts with a complex ecosystem composed of stromal cells, including activated fibroblasts and extracellular matrix (ECM). ECM, mainly produced by fibroblasts, is composed of adhesion and structural molecules such as fibronectin and collagen. It constitutes a dynamic network with biochemical and mechanical properties that influence tumour progression. Thus, the stroma in which melanoma cells are anchored and their interactions with the ECM contribute to anti-cancer treatment resistance. This resistance provided by the matrix is defined as MM-DR (Matrix Mediated-Drug Resistance).Firstly, my study showed, using a 3D model of ECM produced by fibroblasts, that FRCs (Fibroblast Reticular Cells) or different populations of MAFs (Melanoma Associated Fibroblasts) isolated from biopsies of lymphatic metastases produce and remodel an ECM rich in collagen fibres, scaffolding enzymes and matrix proteins and these ECMs are more rigid than those produced by dermal fibroblasts. Furthermore, I observed a protective effect of these matrices on melanoma cells carrying the BRAFV600E mutation to targeted therapies. Adherence of melanoma cells to the ECM lead to resistance in response to the antiproliferative effects of BRAF and MEK inhibitors.Additionally, I identified the discoidin domain receptors, DDR1 and DDR2, which have tyrosine kinase activity and interact with collagen, thereby playing a key role in MM-DR. Using the RNA interference and pharmacological approaches which targeted DDR kinase activity, I showed that inhibition of DDR1 and DDR2 re-sensitised melanoma cells cultured on ECM to the cytostatic and cytotoxic effects of Vemurafenib. These results were confirmed with an in vivo approach using a preclinical tumour xenograft model. Treatment of mice with the combination of Vemurafenib / Imatinib (a DDR inhibitor clinically used in the treatment of certain leukemias) greatly reduces tumour growth, prevented the development of resistance in response to Vemurafenib and increased mice survival.In conclusion, my thesis has highlighted the remarkable structural, mechanical and functional properties of the ECM produced by metastatic lymphatic niche fibroblasts in the survival and therapeutic resistance of melanoma and demonstrated a new role of DDRs in their escape from targeted therapies. Thus, inhibition of DDRs in combination with inhibitors of the MAPK pathway may represent a new therapeutic strategy for BRAF mutant melanoma
Zerhouni, Marwa. "Mécanismes de résistance aux thérapies ciblées dans le mélanome cutané métastatique et les syndromes myélodysplasiques : Caractérisation et validation préclinique de composés innovants". Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ6008.
Cutaneous metastatic melanoma (CMM) and myelodysplastic syndromes (MDS) are two incurable cancers developing resistance to their reference antitumor treatments. Cells resistant to these therapies are characterized by a metabolic reprogramming which profoundly influences and promotes tumor progression. Therefore, inhibition of metabolic pathways seems to be a promising therapeutic strategy to overcome resistance in these two pathologies.The two teams involved in this thesis project have a long-lasting collaboration in the field of cancer. In this context and in partnership with the Nice Institute of Chemistry, our two teams have developed innovative compounds targeting intra-cellular energy balances and the AMPK pathway. Among these compounds, we were more specifically interested in AICAR (Acadesine). Screening efficiency and structure-activity studies enabled us to optimize the structure of our compounds. Based on their solubility, their stability, and their ability to induce tumor cells death, we have identified HA 344 as a lead compound.This study describes the characterization and validation of a new covalent inhibitor, HA 344, derived from Acadesine, effective on CMM and MDS cell lines either sensitive or resistant to their reference treatment but also on CMM and MDS patient cells. By combining click chemistry, proteomics, and metabolomics approaches, we have identified this molecule as a covalent inhibitor of two different metabolic hubs within cancer cells. HA 344 inhibits the final and rate-limiting step of glycolysis through its covalent binding to the pyruvate kinase M2 (PKM2) enzyme, and concurrently blocks the activity of inosine monophosphate dehydrogenase (IMPDH), the rate-limiting enzyme of de novo guanylate synthesis. HA 344 efficiently eliminates tumor growth of BRAF inhibitor sensitive- and resistant-CMM cells both in vitro and in vivo. Thus, this specific mechanism of action of HA 344 provides potential therapeutic avenues not only for patients with CMM but also a broad range of cancers
Mouracade, Pascal. "Etude des voies signalétiques impliquées dans la résistance aux agents thérapeuthiques dans le carcinome à cellules rénales humain". Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAJ055/document.
The renal cell carcinoma is characterized by a high resistance to therapies. Our working hypothesis was that proliferative signaling pathways, anti-apoptotic and / or angiogenic are involved in resistance to therapies. Thus, as part of this thesis, we measured the sensitivity to chemotherapy and targeted therapies in kidney cancer cell lines in vitro as well in vivo.A pilot study was conducted on the basis of the A498 cell line xenografts in nude mice, and then used for analysis on proteome arrays to identify the signaling pathways induced by sunitinib. In vitro, the cell lines of RCC were sensitive to therapy regardless of the VHL status. In vivo, the line A498 appeared resistant to sunitinib. The approach using the proteome array has shown that several angiogenesis proteins are modulated as a result of treatment, including angiogenin. There was no change in the expression of proteins of apoptosis. Phosphorylated forms of Akt were also increased in the treated tumors, as well as Lim1 whereas the phosphorylated form of NFkB was reduced. This work has identified potential targets involved in resistance mechanisms and should define new therapeutic options in renal cancer
Beganton, Benoît. "Caractérisation des réseaux d’interactions protéiques associés aux mutations oncogéniques principales retrouvées dans le cancer du poumon non à petites cellules". Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTT157/document.
Lung cancer is the leading cause of cancer-related death in France and in the world. It is a cancer of poor prognosis, diagnosed at the late stage III or IV, with a 5-years survival of 6% and 1%, respectively. This cancer encompass several histological types, and among them adenocarcinoma account for 40% of the diagnosis. Genetic sequencing of stage IV tumors highlights redundant mutations, and generally exclusives from each other’s, of KRAS, EGFR, BRAF and ALK genes. The identification of these mutations enable, within companion test, to make eligible patients for targeted therapies when molecules are available.Even though these targeted therapies represent a true revolution in patient’s care, the majority of them cannot benefit from these treatments because their tumors do not harbor activating mutations that are targetable (e.g. absence of EGFR, BRAF and ALK mutation, presence of KRAS mutation). Additionally, when they can be treated using an oral molecule, the benefit observed is unfortunately poor in terms of period of time, and all the patients will escape from the treatment. This is for example the case with EGFR mutations.To better understand the molecular mechanisms associated with the resistance events observed in the clinic, and to propose new therapeutics for patient not-eligible for targeted therapies, I studied at the proteome level, the impact these mutations on protein networks, using the BioID technology (proximity-dependent biotinylation identification). More particularly, I have been interested in the activating mutation of EGFR, KRAS, BRAF and ALK. Considering that proteins from the RAS family (HRAS, NRAS and KRAS) are mutated in around 30% of cancers, I have been also interested in the protein network of these proteins to highlight interaction specific to the KRAS isoform.During my thesis, I showed that the protein networks characterized using BioID are much more dense compared to those identified with the more conventional technic of AP-MS (Affinity-purification and mass spectrometry), and that they enable to identify interactors specifically deregulated upon activating mutation. Additionally, the HEK293 cell model (Human Embryonic Kidney) and BEAS2B cell model (non-cancerous lung cell line) showed a high overlapping degree of the interactors identified, suggesting that the strategy used is relevant to identify interactors specific to mutations. This thesis enabled to identify several interactors specific to the mutant KRAS, EGFR, BRAF, NRAS and EML4-ALk fusion. Thirteen interactors specific to the mutated-KRAS have been functionally validated in lung-cancer cell lines models. Finally, using BioID data I have been able to propose a model of EGFR resistance to targeted therapies. This model shows that CBL and IGH2R might be the EGFR partners responsible for therapeutic escape.Altogether, this thesis propose new perspective to determine resistance mechanisms and to identify new therapeutic targets for KRAS-mutated patients
Pohorecka, Magdalena. "Rôle de c-Jun dans la réponse aux inhibiteurs de la voie des MAPK dans les mélanomes". Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30373.
It is clearly recognized that the MAPK pathway is essential for melanomagenesis. The development of new drugs targeting this pathway such as BRAF inhibitors and/or MEK inhibitors has been a major advance in the therapeutic management of melanoma. However, patients still relapse suggesting the emergence of mechanisms of resistance. Many data show that both the expression and activation of the transcription factor c-Jun are induced after treatment of BRAF-mutant cells with MAPK pathway inhibitors (MAPKi). Furthermore, depletion of c-Jun sensitizes cells to these inhibitors triggering apoptosis. We depleted BRAF-mutant melanoma cell lines for c-Jun by siRNA and treated cells with a BRAF inhibitor (PLX4032). Whole genome expression was then analysed by transcriptomic study to determine target genes of c-Jun that could be associated with pharmacological response to MAPKi. This study revealed that SLIT And NTRK Like Family Member 6 (SLITRK6) is a target gene of c-Jun that could be associated with antitumor pharmacological response to MAPKi. Indeed, SLITRK6 mRNA and protein are induced in BRAF-mutant melanoma cell lines after BRAF inhibitor treatment alone or in combination with MEK inhibitor (AZD6244). We also show that the combination of MAPKi with an antibody conjugated with a cytotoxic drug targeting SLITRK6 increases BRAF-mutant melanoma cell death triggering apoptosis in vitro. Finally, our data show that SLITRK6 could be a new pharmacological target for the treatment of BRAF-mutant metastatic melanoma and/or a potential biomarker of resistant cells to MAPKi
Poiraudeau, Loïc. "Identification de nouvelles cibles thérapeutiques dans le cancer neuroendocrine de la prostate". Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASL143.
Prostate cancer is the most common cancer in men and the second leading cause of cancer death in men in industrialized countries. The systemic treatment of these cancers is androgen deprivation therapy (ADT), which can be achieved through surgical or pharmacological castration. Metastatic castration-resistant prostate cancer (mCRPC) is treated with androgen receptor inhibitors (ARi). However, approximately one-third of patients are not responsive to these drugs and the others, who are initially responsive, unfortunately develop secondary resistance, which is acquired within approximately 1-2 years. The mechanisms that explain primary and secondary resistance are not well understood. Neuroendocrine differentiation (NE) of mCRPC is one of these mechanisms. In fact, between 15 and 20% of resistant tumors evolve into neuroendocrine prostate cancer (NEPC). The prognosis of these patients is very poor because the precise molecular mechanisms involved in neuroendocrine differentiation are not clearly elucidated and there is no therapeutic solution adapted to these tumors.The objective of this thesis was to study neuroendocrine differentiation in order to identify new therapeutic targets. We relied on the MATCH-R study, which aimed to study the mechanisms of resistance to targeted therapies (enzalutamide, abiraterone). Patient biopsies were characterized using high-throughput sequencing and immunohistochemistry methods. As part of this study, the laboratory also developed and characterized preclinical patient-derived xenograft (PDX) models. We show from WES and RNAseq performed on patient biopsies that neuroendocrine differentiation is likely the result of transcriptomic and epigenetic alterations. Moreover, our PDXs retain the genetic, molecular, and pharmacological characteristics of their original biopsies. RNAseq analysis identified a membrane protein, which is specifically expressed by NEPC. The expression of this protein is correlated with the expression of NE markers such as synaptophysin (SYP) and chromogranin A (CHGA), as well as a worse diagnosis. Treatment of our NEPC PDXs with a single intravenous injection of an antibody-drug conjugate targeting this protein, resulted in a significant decrease in tumor volume in the treated group compared to the untreated group. Finally, we identified an orphan nuclear receptor, NR0B2 that is overexpressed in NEPC and could be involved in resistance to ARi. NEPC are aggressive tumors with few therapeutic options. These tumors result from transcriptomic alterations and require the development of relevant models that recapitulate the complexity of the disease to identify potential targets for new targeted therapies. ADCs are promising therapies, especially in NEPC, and have shown anti-tumor efficacy in preclinical evaluation
Pacheco, Nieva Yovana. "Réponse immune cellulaire et thérapie de l'infection par le VIH". Nantes, 2010. https://archive.bu.univ-nantes.fr/pollux/show/show?id=59e1f838-c420-42d8-b4a6-49b9bf87c144.
During HIV infection antiretroviral tritherapy efficiently inhibits viral replication and restores CD4 counts in infected patients. Nevertheless treatment failure may occur. In this work, we investigated two different aspects of this problem : Firstly, HIV sequence variability may provoke the emergence of resistant viruses leading to virological failure. The fact that many drug resistance mutations in HIV fall within CTL epitopes suggests that the immune response play a role in inhibiting resistant virus. In order to address this question we analyzed the response against the RT181-189 epitope covering the Lamivudine resistance mutation, M184V in 34 HLA-A2+ HIV+ infected patients. We found that RT181-189 is frequently recognized by ART Naive patients and poorly recognized by patients with virological failure under Lamivudine treatment. Both viral load and viral sequence polymorphism were associated with the presence of a CTL response against RT181-189. Secondly, some patients may undergo immunological failure; the recovery of CD4+ T-cell counts is incomplete despite complete suppression of viral replication. The aim of our study was to compare the effects of IL-2, IL-7, IL-15 and an agonist of IL-15, RLI, on CD4+ and CD8+ lymphocytes from HIV-infected patients, in order to evaluate the therapeutic potential of these molecules on immune reconstitution. Overall our results indicate that the proliferative response of CD4+ T-cells to IL-7 is preserved, even in patients with low CD4+ T-cell counts, and that both IL-15 and RLI can induce homeostatic proliferation of CD4+ effector-memory T-cells. In, RLI did not show greatly increased potency compared to native IL-15
Marthinet, Eric. "Modulation du phénotype typique de multichimiorésistance (MDR) des cellules cancéreuses humaines par des leurres transcriptionnels et étude de la régulation transcriptionnelle du gène MDR1 au niveau de la région MED-1". Lyon 1, 2001. http://www.theses.fr/2001LYO10021.
Billaud, Amandine. "Analyse moléculaire, enjeux et limites des thérapies ciblées en oncologie : extension des sensibilités aux anti-PARP dans les cancers ovariens par caractérisation de variants non annotés et nouveaux mécanismes de résistance dans les cancers bronchiques. Caractérisation moléculaire de l’EGFR dans les cancers bronchiques non à petites cellules : étude prospective comparative des technologies NGS et automate Idylla Somatic mRNA analysis of BRCA1 splice variants provides a direct theranostic impact on PARP inhibitors". Thesis, Angers, 2020. http://www.theses.fr/2020ANGE0003.
Despite significant clinical benefit from the consideration of molecular context, targeted therapies are still challenging. First part of this work focused on tyrosine kinase inhibitors targeting EGFR in non small cell lung cancers. Thus, improvement of biomarkers detection methods was completed by in vitro characterization of an unreported mechanism of acquired resistance. Briefly, pulmonary cells were exposed to a mutagen agent and a selection pressure was applied with EGFR inhibitors allowing the detection of TBK1 signature. Finally, synergic effect of that co-inhibition was highlighted. Now essentials in gynaecological cancers management, PARP inhibitors represent the second part of that work. Those targeted therapies are based on synthetic lethality. Consequently, BRCA1/2 pathogenic mutations are required for their administration, illustrating the issue of variants of uncertain significance. Toward their functional characterization necessity, a transcriptional analysis of splicing variant was first conducted on mRNA extracted from FFPE samples. Then, to evaluate functional signification of all types of variants, genomic edition was developed. Editing efficiencies of the unknown variant and a silent control one were compared in a haploid model where those genes are essentials. Functional signification of BRCA1/2 variants, and thereby mutations from all essential tumor suppressor genes in our model, can be evaluated in three weeks which is compatible with clinical management
Sala, Margaux. "Implication des récepteurs à domaine discoïdine dans la résistance à la thérapie ciblée au cours du mélanome". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0400.
The combination of two treatments, an anti-BRAF plus an anti-MEK is currently used in first line in patient management presenting metastatic melanomas and harboring the BRAF V600E somatic mutation. However, the main issue during targeted therapy is the acquisition of cellular resistance in 80% of the patients, which is associated with an increase of metastasis formation, notably due to the hyperactivation of MAP kinase pathway. Different receptors are known to activate this signaling pathway and previous reports have indicated that Discoidin Domain Receptors (DDRs) 1 and 2 can activate MAP kinase pathway. Then, in order to study the role of DDRs in melanoma cells resistance to the targeted therapy, we firstly determined, that DDRs are overexpressed in Vemurafenib resistant cells compared to sensitive ones. We hypothesized that resistant cell lines, despite the bi-therapy, are able to over-activate MAP kinase pathway through DDRs activation. We also reported that DDRs depletion or inactivation by DDRs inhibitors such as Dasatinib or CR-13542 reduced tumor cell proliferation, due to a decrease of MAP kinase pathway activity in resistant cells. We finally confirmed those results in vivo, in a xenograft mouse model. As a result, we characterized DDRs as new therapeutic targets in resistant patient with metastatic melanoma. Therefore, we propose that Dasatinib, an FDA approved drug, could be a second treatment after the targeted bi-therapy in resistant patients overexpressing DDRs
Bertorello, Juliette. "Reprogrammation traductionnelle par eIF3 liée à la résistance aux traitements des glioblastomes". Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30096.
The intrinsic resistance to current therapies, leading to an almost systematic relapse of patients, is a characteristic of glioblastomas (GBM), the most common and aggressive brain tumor. Understanding the underlying mechanisms of such a malignant tumor is therefore an urgent medical need. Several studies support the notion of a deregulation of the translation machinery, in particular during the initiation stage, contributes to the malignant transformation and progression of cancers, in part via a selective translation of the specific transcripts involved in the development and maintenance of cancer cells. Our work focuses on the eIF3 factor, a multimeric complex participating in the initiation of translation and frequently deregulated in GBM. Our results show that the deregulated expression of eIF3e, the subunit (e) of the eIF3 complex, in specific GBM regions, could influence the synthesis of specific proteins impacting the development of the disease. In particular, eIF3e restricts the expression of proteins involved in the response to cellular stress and increases the expression of stem cell markers. Our results also show that the activation and repression effects of eIF3e on translation could be partially explained by a distinct binding model of eIF3e, eIF3d and DDX3X (a RNA helicase) on target mRNAs. Finally, the data obtained allow us to better understand how the intratumor heterogeneity of eIF3 expression results in the activation of signaling pathways specific to each tumor region in GBM, an essential concept to take into account in the development of future more targeted and personalized treatments for patient
St-Onge, Julie. "Utilisation des antibiotiques et tests diagnostiques en thérapie parodontale : une étude transversale sur les pratiques courantes des parodontistes au Canada". Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/34017.
Considering the emerging problem of bacterial resistance, this study was designed to evaluate the use of antibiotics and microbial diagnostic tests in periodontal therapy to determine whether the current clinical practices of Canadian periodontists are consistent with available literature. The data were collected through an electronic questionnaire sent by email and completed anonymously. There are 64 of the 322 periodontists contacted who participated in this study. A participation rate of 19.88 % was then obtained. The results show that 59.38 % of periodontists practicing in Canada use local antibiotics. However, participants mentioned using it rarely and mainly for the management of refractory periodontitis (39.47 %) and localized severe chronic periodontitis (21.05 %). Moreover, minocycline is the most frequently used local antibiotic. For systemic antibiotic therapy, the majority of Canadian periodontists demonstrated similar clinical practices. In fact, similarities were observed for frequency of use and antibiotic choice in various periodontal conditions evaluated. The combination of amoxicillin and metronidazole is the most frequently selected systemic antibiotic therapy for different periodontal conditions. Finally, 82.81 % of participants never use microbial diagnostic tests in their practice and this non-use was justified by the lack of benefits associated with these tests. In conclusion, a certain similarity between the practice habits was denoted for antibiotic therapy and diagnostic tests. Thus, the overall use of antibiotic therapy by Canadian periodontists respects current scientific evidence. The low use of diagnostic tests reported in this project reflects the lack of literature clearly supporting the clinical benefits of using these tests in periodontal therapy.
Labialle, Stéphane. "Élément invMED1 et complexe LRP130 d'activation du gène MDR1 humain : découverte et application à la génothérapie du phénotype de multi-chimiorésistance des cancers". Lyon 1, 2004. http://www.theses.fr/2004LYO10032.
Losson, Hélène. "Combinaisons de nouveaux inhibiteurs de désacétylase d’histones 6 avec des inhibiteurs de tyrosine kinase pour le traitement de la leucémie myéloïde chronique". Thesis, Université de Lorraine, 2020. http://www.theses.fr/2020LORR0003.
Breakpoint cluster region-Abelson (BCR-ABL)+ chronic myeloid leukemia (CML) patients receive tyrosine kinase inhibitors (TKIs) such as imatinib as the first-line treatment; however, some patients develop resistances and severe adverse effects. Combination treatments, especially with histone deacetylase (HDAC)6 inhibitors (HDAC6i), appear as an attractive option to prevent TKI resistances considering the capacity of HDAC6i to downregulate BCR-ABL. Moreover, HDAC6 is implicated in protein degradation pathways, so that its inhibition combined with that of the proteasome could sensitize cells to TKIs. Thus, we hypothesized that HDAC6i combined to TKIs could be effective for CML treatment. In the first part, we compared the anti-CML effects of a HDAC6i identified in our laboratory, compound 7b, to the reference HDAC6i tubacin, in combination with imatinib. Results showed that the imatinib-7b combination generated stronger anti- CML effects than imatinib-tubacin. Especially, the imatinib-7b combination elicited a potent synergistic caspase- dependent apoptotic cell death and drastically reduced the proportion of cancer stem cells in K562 CML cells, whereas it only moderately impacted various healthy cell models. Ultimately, the imatinib-7b combination decreased more potently the colony forming capacities and tumor mass formation of CML cells in a semisolid methylcellulose medium and in xenografted zebrafishes, respectively, compared to each compound alone. Mechanistically, the combination induced BCR-ABL ubiquitination and downregulation leading to a dysregulation of multiple key proteins of its downstream pathways involved in CML proliferation and survival. Results tend to demonstrate that 7b could target the second site. In the second part, we initiated a study of a novel hydroxamate-based HDAC6i, MAKV-15, and preliminary results demonstrated it triggered BCR-ABL downregulation. Accordingly, in pre-treatment with bortezomib it sensitizes CML cells to imatinib leading to enhanced caspase-dependent apoptotic death in imatinib-sensitive and imatinib-resistant CML cells. Considering that HDAC6 is reported to possess two functional catalytic sites, we finally attempted to determine which catalytic site is targeted by these HDAC6i. Taken together, our results suggest that HDAC6i potentiate the effect of imatinib and could overcome TKI resistance in CML cells and therefore such combination may represent a promising therapeutic approach for CML patients
Resnier, Pauline. "Nano-Vectorisation de siRNA via des nanocapsules lipidiques : contournement de la résistance du mélanome aux chimiothérapies conventionnelles". Thesis, Angers, 2014. http://www.theses.fr/2014ANGE0006/document.
Metastatic melanoma represents the most aggressive form of skin cancer with a median survival around 13 months. The low efficacy of actual chemotherapy is explained by important resistance phenomenon. The objective of this work consists in developing a new alternative strategy based on siRNA (small interfering RNA) encapsulated into lipid nanocapsules (LNCs) for intravenous injection. Firstly, the experiments were focused on development and optimization of formulation process for the encapsulation of siRNA into LNCs. The result demonstrated an encapsulation efficiency evaluated at 35% by spectrophotometer analysis, an important stability at 4°C (for at less 3 month) and an efficient gene inhibition in melanoma cells. The second part of this work studied the melanoma targeting potential of surface modified LNCs after systemic injection. In this way, pegylation with different polymers and Affitin grafting (affinity peptide) was performed on siRNA LNCs. The biodistribution on healthy animals and subcutaneous melanoma tumor bearing mice revealed the distinct behavior of various modified LNCs. All pegylated LNCs showed a preferential accumulation in tumor site in comparison with non-modified or Affitins LNCs. In a third part, the anti-cancer efficacy was tested with siRNA targeting Bcl-2, an anti-apoptotic member, or Alpha 1 subunit of Na/K ATPase. A reduction of tumoral volume evaluated at 25% was observed for Bcl-2 siRNA LNC. Moreover, the association with new promising anticancerous drug, ferrocifens, and Bcl-2 siRNA co-encapsulated into LNCs evidenced promising effects. This work demonstrated the capacity of LNC to deliver siRNA into melanoma cells and tumor after systemic administration thank to new targeting strategies in melanoma
Joha, Sami. "Mécanismes de résistance aux inhibiteurs de tyrosine kinase sur le modèle de leucémie myéloïde chronique". Phd thesis, Université du Droit et de la Santé - Lille II, 2009. http://tel.archives-ouvertes.fr/tel-00451045.
Ly, Nary. "Caractérisation moléculaire du VIH-1 et premières données de la résistance aux antirétroviraux au Cambodge". Bordeaux 2, 2006. http://www.theses.fr/2006BOR21336.
Genetic variability of HIV-1 has multiple implications, especially in regard to antiretroviral (ARV) drug resistance. Mutant resistances to ARVs are well characterized for B subtype but new data are needed for non-B subtypes. This research project investigated CRF01_AE in Cambodia. A first study has characterized viral isolates from adult patients naive to ARVs. It showed a large predominance of CRF01_AE (95,5 %), and a low prevalence of drug resistance mutations (DRM), lower than World Health Organization's 5 % threshold. A second study involved pregnant women who received nevirapine single dose prophylaxis for prevention of mother-to-child HIV-1 transmission. We observed incidence rates of DRM to nonnucleoside reverse transcriptase inhibitors of 18,8 % to 31,3 % according to the sampling time. Cambodian CRF01_AE mutations are generally similar to those observed in A, D and CRF02_AG subtypes. A last study involved adult patients in therapy failure under HAART. The DRM observed were those expected for the B subtype. Other substitutions were also detected in these patients but should be confirmed on larger samples. These data could lead to the partial update of algorithms
Michaud, Mickaël. "Modulation du phénotype de multichimiorésistance des cancers : identification de cibles potentielles et développement de nouveaux outils génothérapeutiques". Lyon 1, 2007. http://www.theses.fr/2007LYO10017.
The chemoresistance of cancers is a major cause of failure of chemotherapy. It results from the multidrug resistance phenotype (MDR), due in particular to the overexpression of the MDR1 gene. MDR1 produces P-glycoprotein (P-gp) that ejects drugs out of the cell. We showed the existence of P-gp dimers, particularly in cholesterol-enriched membranes, the formation of which depends on P-gp glycosylation. We could modulate the MDR phenotype in vitro by decreasing the production of ABC transporters (P-gp, MRP1, BCRP) and other proteins (MVP and LRP130) by using RNA interference. Lentiviral vectors carrying modulator siRNAs allowed us to transfect MDR cell lines that were hardly transfectable by other means. With this tool we could evidence a new role of LRP130 in the apoptosis of MDR cells that is complementary of its MDR1 trans-activating activity. This work opens new prospects and proposes original solutions in the chemotherapy of MDR cancers
Jebahi, Abdelghani. "Recherche d'outils d'inhibition de la protéine anti-apoptotique Mcl-1 pour la sensibilisation des cancers de l'ovaire à la molécule BH3-mimétique ABT-737". Caen, 2015. http://www.theses.fr/2015CAEN4014.
Ovarian cancers are addicted to Bcl-xL and Mcl-1 anti-apoptotic proteins. Efficient inhibition of these targets is an attractive strategy for the therapeutic management of such disease. Navitoclax, an orally bioavailable analogue of the potent Bcl-xL inhibitor ABT-737, is a promising drug candidate. However, Mcl-1 has been widely described as a key resistance factor to ABT-737. Mcl-1 inhibition thus constitutes a major challenge for the clinical success of Navitoclax. We have addressed this issue with two strategies: inhibiting signaling pathways controlling Mcl-1 expression, and looking for new specific inhibitors by screening a representative sample of the French National Chemical Library (CNE, 640 compounds), selected according to diversity criteria. BEZ235, a dual inhibitor of PI3K/Akt/mTOR pathway, strongly repressed Mcl-1 expression and induced Puma expression in both ovarian carcinoma cell lines tested while differentially modulating BIM. Interestingly, BEZ235 efficiently sensitized ovarian carcinoma cells to ABT-737, provided that BIM expression was induced. Moreover, inhibiting the ERK1/2 pathway restored BIM expression and sensitized low BIM-expressing cancer cells to the BEZ235/ABT-737 treatment. Otherwise, we identified new potential specific Mcl-1 inhibitors. Four small molecules were produced by structural optimization of MIM1, a recently discovered specific Mcl-1 inhibitor. We have also developed a specific functional screening assay and selected 12 hits from « Essential Compound National Library ». These results open interesting perspectives for Mcl-1 targeting for future improvement of the clinical management of ovarian cancers
Mazaheri, Mahta. "Molecular basis of anti-hormonal treatment and resistance in breast cancer". Toulouse 3, 2009. http://thesesups.ups-tlse.fr/610/.
Breast cancer is the most common type of malignancy among women in the world. Approximately 70% of breast tumours express the estrogen receptor alpha (ERa) and are considered hormone-responsive. Endocrine therapies have long been the treatment of choice. However, the estrogen- like agonist effect and development of resistance of the available selective estrogen receptor modulator such as tamoxifen require developing new treatments that act through different mechanisms. The objective of our study is to design tools that can help to understand the molecular mechanisms involved in ligand-dependent modulation or degradation of ERa. We selected a set of anti-estrogens with different structures and compared their effect on: 1. ERa degradation. 2. Intra-cellular localisation of ERa. 3. Regulation of transcription of ERa- endogenous target genes. 4. Regulation of transcription in the mutants of ERa. Using this mechanistic study we could classify the tested anti-estrogens into three groups based on their function: SERM, SERD and a new group for EM652. SERM (selective estrogen receptor modulator) include compounds such as OH-tamoxifen and RU39411, that stabilise ERa, that re-localize ERa into the nucleus upon binding, that increase transcriptional activity in mutants affecting the recruitment of cofactors or the binding of their side chain and that lack inhibitory capacities of the basal expression of endogenous genes. SERD (selective estrogen receptor modulator) include compounds such as ICI182580 or RU58668, that induce nuclear proteasome-dependent degradation ERalpha which occur in large nuclear foci that colocalize with the proteasome and that inhibit basal gene expression of the endogenous progesterone receptor gene (PGR). Finally, EM652 was found to affect ER degradation and localisation similarly to SERM but inhibited basal gene expression of the endogenous PGR
Joha, Mohamad Sami. "Mécanismes de résistance aux inhibiteurs de tyrosine kinase sur le modèle de leucémie myéloïde chronique". Lille 2, 2009. http://www.theses.fr/2009LIL2S042.
Brotin, Emilie. "Chimiosensibilisation des cancers de l’ovaire par inhibition de l’expression de Bcl-xL : développement d’une stratégie ARN interférence". Caen, 2007. http://www.theses.fr/2007CAEN4069.
In ovarian cancers, cisplatin exposure of sensitive cells has been associated with a down-regulation of Bcl-xL expression in conditions inducing massive apoptotic cell death, whereas recurrence (which is the major causes for therapeutic failure) was systematically observed when Bcl-xL expression was maintained. In order to impede Bcl-xL expression we developed a specific siRNA, and evaluated its ability to induce apoptotic cell death in response to cisplatin in the highly resistant cells SKOV3. Our siRNA (siXL1) led to the disappearance of both Bcl-xL mRNA and protein, associated with a low rate of apoptosis induction. When transfection was combined to cisplatin exposure, we observed a massive induction of cell death, whereas cisplatin alone was only transiently cytostatic. A multi-target strategy is also currently developed. This work emphasizes the interest of the inhibition of Bcl-xL expression as a chemosensitizing tool for the treatment of ovarian carcinoma. We thus investigated siXL1 effect on survival of SKOV3 tumour bearing mice. We showed that the administration of siXL1, allows a strong increase of survival rate, half of the mice being cured, in contrast to the inefficiency of cisplatin. The administration of siXL1 significantly decreased both Bcl-xL expression and proliferation in tumour nodes. We particularly investigated the importance of administration conditions, and currently research the effect of siXL1 on tumour stroma cells. These results, patented in 2006, confirm the interest to target the anti-apoptotic Bcl-2 family members for the treatment of ovarian carcinomas, and are currently under preclinical validation
Jeannot, Victor. "Identification et vectorisation de combinaisons de traitements pour la thérapie des tumeurs pulmonaires résistantes aux inhibiteurs de tyrosine kinase de l'EGFR". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAV061/document.
Responsible of 30000 deaths each year in France, lung cancer is a major public health problem. One of the current challenges is to adapt the treatment of lung cancer to offer more effective and less aggressive targeted therapies. EGFR tyrosine kinase inhibitors (EGFR-TKI, gefitinib and erlotinib) represent a real progress in lung cancer therapy. However resistance mechanisms have been described and combination of targeted therapy with EGFR-TKI could overcome resistance in lung cancer.In this context, we studied mechanisms involved in resistance to EGFR-TKI. We show that PI3K/AKT activation is a major pathway leading to EGFR-TKI resistance leading to apoptosis inhibition through acetylation-dependent mechanisms. Histone deacetylase (HADCs) and sirtuin are involved in these mechanisms and modulate PI3K/AKT activation and apoptosis. The use of HDACs inhibitors (HDACi) and sirtuins inhibitors thus restores the sensitivity to EGFR-TKI. Altogether these results confirm the therapeutic effect of the EGFR-TKI/HDACi combination and show the therapeutic potential of the association of EGFR and PI3K/AKT inhibitors to overcome EGFR-TKI resistance.Therapeutic molecules must specifically reach the tumor site, sometimes requiring to protect them against degradation, to reduce their side effects, and to control their release in time and space, using transporters. In the second part of this thesis, we have thus evaluated the lung tumors targeting capabilities of amphiphilic copolymer-based nanoparticles, containing an hydrophilic polysaccharidic block (hyaluronan) and an hydrophobic polypeptidic block (the poly(γ‐benzyl L‐glutamate PBLG). Our work highlights the tumor targeting capability of these nanoparticles injected intravenously, offering new lung cancer therapy perspectives. Our aim is to load the drugs combination (EGFR-TKI/HDACi) in these vectors, to treat the lung tumors resistant to EGFR-TKI
Attaoua, Chaker. "Etude des mécanismes moléculaires de résistance différentielle du mélanome malin aux vincalcaloïdes". Thesis, Montpellier 1, 2013. http://www.theses.fr/2013MON13505.
Malignant melanoma (MM) is a very refractory tumor to anticancer therapies, including vinca alkaloïds (VAs). To investigate the role of GSTM1 (glutathione S-transferase μ1) and MRP1 (multidrug resistance protein 1) in MM acquired resistance to VAs, we established 4 cellular models of resistance to vincristine (CAL1R-VCR), to vindesine (CAL1R-VDS), to vinorelbine (CAL1R-VRB) and to vinflunine (CAL1R-VFL), by continuous exposure of MM cells (CAL1-wt), for one year, to these anticancer agents. The expression of a functional GSTM1 is specifically observed (RT-PCR, western blot, total GST activity) in resistant cells. Curcumin (GSTM1 inhibitor), BSO (glutathione synthesis inhibitor) and MK571 (MRP1 inhibitor), considerably reduce the acquired resistance to VCR and VDS but not that to VRB or VFL. However, all these VAs specifically reduce GSTM1 activity. These data show the differential involvement of GSTM1 and MRP1 in resistance to VAs. To determine the molecular mechanisms of this chemoresistance, we performed a pangenomic study (Affymetrix HG-U133 Plus 2.00 microarrays) on the CAL1 lines (wt and R). The hierarchical clustering (by Cluster and TreeView) of array data revealed a similarity between the gene expression profiles of CAL1R-VRB and CAL1-wt, but also between those of CAL1R-VCR and CAL1R-VDS. The bioinformatic analysis (by IPA) of the most differentially expressed transcripts between cell lines, highlighted 6 gene networks known for their role in tumor chemoresistance. FatiGO program revealed 3 biological terms overrepresented (>60%) in CAL1R (ribosome, intermediate filaments of cytoskeleton, olfactory receptors), while functional study (gene invalidation by siRNA, viability test) of GPR143, KIT and SLC45A2 (genes interacting with NF-kB and CCND1 (tumor chemoresistance factors), highly expressed in CAL1-wt and mute in CAL1R) showed the weak trend of the two formers to be involved in resistance to VAs
Pastor, Marie. "Étude du potentiel des pFAR4, miniplasmides dépourvus de gène de résistance à un antibiotique, comme vecteurs pour la thérapie génique". Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCB043.
One of the main challenges in gene therapy is to identify safe vectors that promote an efficient gene delivery and a sustained therapeutic transgene expression level in targeted cells. The development of novel plasmid vectors allowed to reach these objectives and to consider non-viral gene therapy approaches as attractive alternatives to treat genetic and acquired disorders. The pFAR4 vector is a novel antibiotic-free mini-plasmid. In Escherichia coli, its propagation is based on the suppression of an amber nonsense mutation introduced into an essential gene, thus eliminating safety concerns classically attributed to antibiotic resistance markers present on conventional plasmid DNA vectors and allowing a reduction in plasmid size. The aim of this work was to investigate the potential of pFAR4 as a gene vector in two different non-viral gene therapy approaches. In a first approach, the potential of the pFAR4 vector was assessed for the expression of a therapeutic gene in mouse liver. To this end, a pFAR4 derivative expressing the Sgsh gene from a liver-specific promoter and coding the sulfamidase, an enzyme deficient in patients suffering from the Sanfilippo A disease, was tail vein hydrodynamically injected into mouse liver. We showed that the pFAR4 derivative promoted a high and prolonged sulfamidase expression which rapidly declined when the same expression cassette was delivered by a conventional plasmid containing a kanamycin resistance marker. It was established that the superior expression profile obtained with the pFAR4 derivative did not result from its integration in host genome but seemed to benefit from protection against transcriptional silencing. In a second approach, the pFAR4 vector was combined to the Sleeping Beauty transposon system that mediates transgene integration into host genomes, after its excision from a plasmid donor by the hyperactive SB100X transposase, in order to obtain a long-term expression in dividing cells. This combination was studied in vitro, delivering either the neomycin resistance gene or the fluorescent Venus protein-encoding gene into HeLa cells. We showed that the combination pFAR4/SB led to an increased transgenesis rate in comparison to the association of SB with conventional plasmids. The pFAR4/SB combination seemed to benefit from an elevated transfection efficiency and a higher excision rate, resulting from the reduced size of the pFAR4 vector. The two technologies should be soon used for the delivery of the anti-angiogenic pigment epithelium-derived factor (PEDF) gene into autologous primary pigment epithelial cells, in the context of two PhaseI/II clinical trials based on an ex vivo gene therapeutic approach for the treatment of neovascular age-related macular degeneration (nAMD)
Rebucci, Magali. "Mécanismes de résistance au cetuximab et influence des associations de traitement dans des lignées cellulaires de cancers de voies aérodigestives supérieures". Phd thesis, Université du Droit et de la Santé - Lille II, 2010. http://tel.archives-ouvertes.fr/tel-00576444.
Cicero, Julien. "TrkA dans les métastases cérébrales des cancers du sein triple négatifs". Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILS031.
Nearly 90% of deaths in breast cancer patients are due to metastasis. Triple-negative(TN) breast cancer is characterized by its aggressive nature and high propensity to metastasize. Among the various sites of metastasis, the development of brain metastasis is associated with the worst prognosis, with a greater impact on patients'quality of life. The mechanisms underlying the progression of brain metastases in triplenegativebreast cancer are incompletely understood. To address this gap, we have used several experimental models to study the behavior of breast cancer cells during the process of dissemination to the brain. These models include an in vitro human blood-brain barrier (BBB) model, in vitro 3D organotypic extracellular matrix, ex vivo co-cultures of mouse brain slices, and in vivo xenograft experiments. By recapitulating the final key steps of brain metastasis in these models, we sought to better understand the underlying molecular mechanisms. In this work, we demonstrate the involvement of TrkA and its co-receptors (e.g. EphA2) in the development of brain metastases. First, we identified the TrkA/EphA2 receptor complex as a mediator of proNGF-induced BBB transmigration. Furthermore, our results showed that combined inhibition of TrkA and EphA2 significantly reduced brain metastasis in a preclinical breast cancer model. These results challenge the current understanding of the mechanisms of brain metastasis and highlight the role of proNGF as a key factor in the brain tropism of metastatic TN breast cancer
Allagui, Ferdaous. "Utilisation du vaccin de la rougeole dans le traitement des cancers résistants aux traitements usuels : modèle du mélanome". Thesis, Nantes, 2017. http://www.theses.fr/2017NANT1029/document.
Metastatic melanoma represents the most aggressive form of skin cancer with a median survival around 13 months. Thus, antitumor virotherapy appears as a potential therapeutic alternative. Live-attenuated measles virus (MV) is a good candidate for this strategy. In this work, we explored the use of MV as a new melanoma treatment strategy. In a first part, we analyzed the oncolytic effect of MV against a panel of human melanoma cell lines established in our laboratory. These cell lines exhibited varying levels of sensitivity to MV infection that cannot be fully explained by their level of expression of CD46 receptor at their surface. In melanoma xenograft mouse models, MV treatment induced important tumor regressions for sensitive cell lines but other were completely insensitive resulting in rapid tumor growth. In a second study, we analyzed the type I IFN response in our panel of melanoma cells to explain these differences in sensitivity. We have therefore, demonstrated that treatment of sensitive cells to MV by type I IFN can block their infection, while the use of ruxolitinib, an inhibitor of type I IFN signaling, on the resistant cell lines, rendered them sensitive to MV. These results confirm oncolytic MV as a viable therapeutic option for malignant melanoma and also suggest that the sensitivity of these cells to MV is dependent on both the level of expression of CD46 and defects of the type I IFN pathway
Figarol, Sarah. "Compréhension des étapes précoces de la résistance adaptative aux inhibiteurs de tyrosine kinase de l'EGFR dans les cancers bronchiques". Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30095.
Lung cancer with EGFR activating mutation benefits from the development of EGFR tyrosine kinase inhibitors (EGFR-TKI). However, the effectiveness of these therapies, although high, is only transitory, and patients inevitably develop resistance phenomena. Previous studies suggest that this resistance could arise from a population of tolerant cells (or Drug-Tolerant Cells, DTC) which, after a pseudo-dormant state, develop new resistance mechanisms including secondary EGFR mutations, MET amplifications, etc. This state of tolerance has been demonstrated in vitro mainly on only one cell line and remains poorly characterized. The objective of this PhD work was to broaden and deepen the study of the mechanisms of resistance to different lung tumor cell lines harboring EGFR activating mutations treated with first (erlotinib) or latest-generation (osimertinib) EGFR-TKIs. Our work shows that duration of the tolerance phase and then the development of EGFR-TKIs resistant proliferative clones are very heterogeneous between the cell lines studied but also within the same cell line. However, most DTC have an enlarged morphology associated with remodelling of the actin cytoskeleton as well as a pseudo-senescent state, which seems to predispose towards the epithelial-to-mesenchymal transition (EMT) developing progressively from the DTC state to the proliferative state, after loss of senescence characteristics. RNA-seq analyses show that gene signatures related to cell contractility are found at the DTC state in the three cell models studied. As previous work in the laboratory has shown the role of the small GTPase RhoB in the regulation of the actin cytoskeleton and in resistance to erlotinib, we investigated its role in tolerance to EGFR TKIs. RhoB, unlike its counterparts RhoA and RhoC, is over-expressed and over-activated in DTC. Moreover, its inhibition by the C3 exoenzyme, a toxin that specifically inhibits RhoA, RhoB and RhoC, allows the eradication of DTC and thus prevents the emergence of resistant clones. Since RhoB is regulated by prenylation and in particular by farnesylation, the combination of a farnesyltransferase inhibitor (FTI) and an EGFR-TKI was analyzed and shows that it effectively prevents the emergence of proliferative clones. These results lead us to propose this combination as a new therapeutic strategy in lung cancers carrying EGFR activating mutations
Lewis, Matthieu. "Identification de voies de résistance aux inhibiteurs de tyrosine kinase dans la leucémie myéloïde chronique par criblage CRISPR-Cas9". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0054/document.
The characterization of malignant tumour growth and the understanding of resistance mechanisms to treatment in cancer is of utmost importance for the discovery of novel “druggable” targets. Efficient genetic screening, now even more possible with the convergence of CRISPR-Cas9 gene editing technology, next-generation sequencing and bioinformatics, is an important tool for deciphering novel cellular processes, such as resistance to treatment in cancer. Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterised by the t(9;22) genetic abnormality, which encodes the driver of CML, the BCR-ABL1 fusion protein. Imatinib mesylate, a tyrosine kinase inhibitor, specifically eliminates CML cells by targeting and blocking the kinase activity of this protein, yet, as for all targeted therapies in cancer, resistance to treatment exists. In order to discover alternative BCR-ABL1 independent mechanisms of imatinib resistance, we utilized the genome-scale CRISPR knock-out library GeCKO v2 to screen for imatinib sensitising genes in vitro on K562 cells. We revealed genes that seem essential for imatinib induced cell death, such as pro-apoptotic genes (BIM, BAX) or MAPK inhibitor SPRED2. Specifically re-establishing apoptotic capabilities in BIM knock-out (KO) cells with BH3-mimetics, or inhibiting MAP-kinase signalling in SPRED2 KO cells with MEK inhibitors restores sensitivity to imatinib, overcoming resistance phenotypes. In this work, we discovered previously identified pathways (apoptosis, MAP-kinase signalling) and novel pathways that modulate response to imatinib in CML cell lines, such as the implication of the Mediator complex, mRNA processing and protein ubiquitinylation. Targeting these specific genetic lesions with combinational therapy can overcome resistance phenotypes and paves the road for the use of precision oncology
Garandeau, David. "Rôle du métabolisme de la sphingosine 1-phosphate dans la résistance thérapeutique des cellules de mélanome aux inhibiteurs de BRAF". Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30134.
The treatment of metastatic melanoma has changed considerably in recent years with the development of targeted therapies, which have shown a significant benefit in overall survival. In particular, the inhibition of the frequently mutated serine-threonine kinase BRAF, by Vemurafenib (PLX4032) showed that survival rates increase by 6 to 8 months compared to standard chemotherapy, Dacarbazine. However, a very small proportion of patients will respond to the long term, and the majority of patients relapses in a median of 6 months. Cellular mechanisms have been identified in the appearance of this acquired resistance, including the involvement of MITF, a major transcription factor of melanocytes, as well as changes in the expression of several members of Bcl-2 family. However, a better understanding of these mechanisms seems essential, as is the use of new therapeutic strategies to optimize treatment efficacy and duration of clinical benefit. Our group recently showed some alterations of ceramide metabolism and its derivative sphingosine 1-phosphate (S1P) in human melanoma cells compared to healthy melanocytes. For instance, S1P lyase (SPL), which degrades S1P, is under-expressed. Conversely, sphingosine kinase 1 (SK1), which produces S1P, is over-expressed in tumor cells, as a direct result of BRAF mutation. These alterations increases the levels of S1P. This lysophospholipid promotes cell survival and the resistance to therapeutic agents in a variety of tumor cells. This PhD project aimed at defining whether S1P metabolism could modulate the resistance of human melanoma cells to PLX4032. Here, we show that SPL overexpression or pharmacological inhibition of SK1 by SKI-I sensitizes metastatic melanoma cells to PLX4032-induced apoptosis. This phenomenon is associated with a decreased expression of the master regulator of melanocyte differentiation MITF as well as its direct cellular target Bcl-2. The decrease in MITF protein can be reversed by treating cells with exogenous S1P. Interestingly, we also report for the first time an increased expression of SK1 as well as the S1P receptors, S1PR1 and S1PR3, in melanoma cells with acquired resistance to PLX4032 as compared to sensitive counterparts. These modifications are associated with high expression of MITF. Overexpression of SPL, treatment with SKI-I or antagonists of S1PR1 ans S1PR3, strongly overcomes acquired resistance to PLX4032 through a decrease in the expression of S1PR, MITF as well as Bcl-2. Thus, by controlling the expression of key proteins in melanoma cell survival and resistance, S1P metabolism could represent a new therapeutic approach to enhance the effectiveness of targeted therapies
Kovalenko, Lesia. "Sélection et caractérisation de molécules ciblant la protéine de la nucléocapside de VIH-1". Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAJ086.
Highly Active Anti-Retroviral Therapy (HAART) is successfully used for HIV-1 treatment, but is hampered by the appearance of drug resistance. Thereby, alternative drug targets are required. One of the most promising target is the nucleocapsid protein (NC), which is highly conserved and plays essential role in HIV life cycle. In this context, the European project THINPAD was organized with the aim to develop NC inhibitors. To fulfil this objective, several approaches were used, including virtual screening, in vitro secondary screening, in cellulo antivirals tests, and toxicity evaluation. For in vitro screening, the specific NC-promoted cTAR destabilization assay was used. Five series of molecules were selected by the first screenings and antiviral tests. After structure-activity relationship studies, only one series was continued until efficacy testing in mice. The compounds of this series exhibit antiviral activity at nanomolar concentrations but are not active in the murine model. The mechanisms of action studies revealed that their antiviral activity was indeed consecutive to the targeting of the NC
Chocry, Mathieu. "Etude des mécanismes de résistance à l'oxaliplatine dans le cancer colorectal : rôle des voies NOX1/Calpaïnes". Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0667.
Colorectal cancer is a major cancer in terms of frequency and mortality. This is the second leading cause of cancer death, with 17,500 deaths in France in 2011. The treatment of advanced stages is based on different chemotherapeuties including oxaliplatin. However, the development of resistance leads to therapeutic failures explaining the low survival rate. It is therefore crucial to identify the mechanisms of resistance and the actors involved and to discover new therapeutic approaches. We first investigated the role played by calpains and NOX1 in the development of resistance to oxaliplatin, studying oxaliplatin-resistant colorectal tumor cells. This allowed us to identify a signaling pathway involved in resistance to this chemotherapy.Secondly, we have studied the reversion of this resistance to oxaliplatin. A screening of different chemotherapies revealed a reversal of the resistant / sensitive status in our selected cells In the first part, our data highlight novel Nox1 regulations which differ according to the sensitivity of the cells to oxaliplatin. Our results also show that p38 MAPK could be a therapeutic target for treating colorectal cancers resistant to oxaliplatin. In the second part, we have identified a new treatment to induce apoptosis in our resistant cells. Indeed, gemcitabine may be a solution to treat patients who do not respond to oxaliplatin-based protocols
Ahmad, Fahmida. "Modelling heterogeneity of triple-negative breast cancer in mice to uncover and target signaling essentiality". Thesis, Aix-Marseille, 2020. http://www.theses.fr/2020AIXM0225.
Triple-negative breast cancer (TNBC) is a highly aggressive, heterogeneous breast cancer subtype, and has currently no effective treatment. The aim of my PhD project was to understand the mechanisms triggering TNBC and to develop new therapeutic approaches.In our lab, we have generated a unique mouse model (MMTV-R26Met mice) in which a subtle increase in the expression levels of the wild-type MET receptor tyrosine kinase leads to spontaneous, exclusive TNBC formation. This model recapitulates formation of lung metastasis, resistance to conventional chemotherapeutic agents and to a set of combined targeted molecular therapies.Proteomic profiling of MMTV-R26Met tumors and machine learning approach showed that the MMTV-R26Met model largely recapitulates TNBC heterogeneity observed in TNBC patients. We identified two new drug combinations highly deleterious for the MMTV-R26Met tumor-derived cell lines, and a panel of human TNBC cells. The first drug combination targets the anti-apoptotic factor BCL-XL and CDK1/2 (cell cycle regulators). The second drug combination, validated by in vivo studies, is based on a combinatorial targeting of BCL-XL and of WEE1 (cell cycle and epigenetic regulator). Mechanistically, we show that combined inhibition of WEE1 and BCL-XL leads to DNA damage, premature entry into mitosis, resulting in mitotic catastrophe and apoptosis.Our findings may be highly relevant for their potential translation to the clinic, also in view of promising studies of monotherapy with BCL-XL and WEE1 inhibitors in phase II clinical trials