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1
de, Foy K. "Analysis of candidate tumour suppressor genes in sporadic ovarian tumours." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598448.
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The aim of this thesis was to identify genes which are important in the initiation and/or progression of sporadic ovarian cancer. A series of ovarian teratomas and carcinomas was collected and three candidate tumour suppressor genes were analysed. The c-mos gene is an ovarian teratoma susceptibility gene in mice; its absence causes the growth of these tumours. Twenty human ovarian teratomas were collected and the coding region of the c-mos gene was analysed for somatic and germline mutations. No disease-causing alterations were found. Germline mutations of the BRCA2 gene predispose individuals to breast and ovarian cancer. To determine whether mutations in BRCA2 are important in sporadic ovarian cancer, loss of heterozygosity studies and mutation analysis were carried out on BRCA2 in a series of sporadic epithelial ovarian tumours. Loss of heterozygosity was identified in 46% of tumours. Four truncating mutations were identified in 50 tumours, two of which were germline and two somatic. All four mutations were accompanied by loss of the second allele. These results suggest that BRCA2 behaves as a tumour suppressor gene but that somatic mutations are not a common even in sporadic ovarian cancer. The insulin-like growth factor II receptor gene (IGF2R) on chromosome 6q is in a region which is frequently lost in ovarian tumours. A loss of heterozygosity analysis of the IGF2R locus in 38 informative epithelial ovarian tumours demonstrated 55% with loss of one allele. To perform mutation analysis of IGF2R, the technique of fluorescent chemical cleavage of mismatch was established in the laboratory and used to analyse IGF2R cDNA from 18 tumours. No disease-causing alterations were identified. Antibodies were used to examine the expression of the IGF2R protein through immunohistochemical studies of 53 ovarian tumour tissue sections. Seven tumours were identified in which epithelial tumour cells stained negatively for IGF2R. No correlation could be found between immunohistochemical results and LOH and mutation analysis results, suggesting that IGF2R is probably down-regulated at the level of transcription or translation in those samples which showed negative staining.
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Liu, Lu. "Oncogenes and tumour suppressor genes in human central nervous system tumours /." Stockholm, 1999. http://diss.kib.ki.se/1999/91-628-3532-7/.
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Discenza, Maria Teresa. "Regulation of expression of the Wilms' tumour 1 tumour suppressor gene." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82855.
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Wilms' tumour, a pediatric kidney cancer that affects 1 in 10 000 children, is an excellent paradigm for studying the relationship between cancer and development. The Wilms' tumour suppressor 1 ( WT1) gene was identified through the study of hereditary cases of Wilms' tumour showing cytogenetic deletions at chromosome position 11p13. The WT1 gene encodes a zinc finger transcription factor necessary for the development of the genitourinary system. WT1 functions as an activator or a repressor, interacts with a number of different protein partners and regulates the expression of several genes important for cellular growth and differentiation. WT1 mRNA is present in tissues of mesodermal origin that undergo a mesenchymal to epithelial transition. Expression of WT1 is tightly regulated both temporally and spatially during development of the urogenital system.We have identified a novel trans-acting factor, named complex D, which shows sequence specific binding to the WT1 promoter. By electrophoretic mobility shift assays (EMSA), we demonstrate that the transcription factor Sp1 binds the WT1 promoter at a site overlapping the complex D binding site. Molecular mass determination experiments and in situ UV crosslinking indicate that complex D is approximately 130 kDa and consists of at least two proteins. Transient transfection assays show that the integrity of the complex D binding site is necessary for maximal activation of a reporter gene, suggesting that complex D may function as an activator.
Similar to WT1, the ETS-domain transcription factor Pea3 is expressed in tissues where mesenchymal-epithelial interactions occur and both gene products are implicated in regulating the expression of genes necessary for the epithelialization of common organs. Transient transfection assays using WT1 promoter-reporter gene constructs identified a Pea3 responsive element in the WT1 promoter. Overexpression of Pea3 transactivates the WT1 promoter and the presence of the intact Pea3 responsive element is necessary for the transactivation. We demonstrate, by EMSA, the sequence specific binding of Pea3 to the responsive element.
WT1 and the paired box domain transcription factor Paired box 2 (Pax2) are expressed at the initial stages of metanephric kidney development and are critical for the initiation of nephrogenesis. We generated WT1/Pax2 compound heterozygous mutant mice to provide an in vivo model for studying the interplay between WT1 and Pax2 during nephrogenesis. WT1+/-/Pax2 1Neu/+ kidneys were 50% smaller that wild type kidneys and displayed a more severe underdevelopment of the medulla, renal calyces and renal pelvis compared to Pax21Neu/+ kidneys. We demonstrate that WT1 and Pax2 proteins physically interact in vitro and in vivo. Our data suggest that WT1 is a modifier of the Pax2 mutant phenotype and that both proteins may be implicated in a common pathway in the transcriptional network governing metanephric development.
4
Judson, Hannah. "Investigation of candidate imprinted tumour suppressor genes." Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/28316.
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Imprinting is an epigenetic phenomenon that silences one allele of a gene, so that expression in one or more cell types is exclusively monoallelic, and dependent on parental origin. Approaches used to identify novel imprinted genes rely on characteristic features such as the clustering of imprinted genes, or their association with differentially methylated CpG islands. An imprinted tumour suppressor gene involved in pathogenesis of neuroblastoma is believed to lie within chromosome 1p36. In this region, a search was initiated for imprinted genes in the vicinity of the imprinted gene TP73. The DFFB gene, encoding the apoptotic nuclease DNA fragmentation factor, was identified, and its intron-exon structure was elucidated. A pseudogene was also identified on chromosome 9. The tumour suppressor candidacy of DFFB was assessed through a comprehensive mutation screen of 42 neuroblastoma DNAs. No tumour-specific mutations were identified. Imprinting was then assessed by RT-PCR, which revealed biallelic expression of DFFB. It is unlikely that DFFB acts as a tumour suppressor in neuroblastoma. During a systematic screen, a differentially methylated CpG island, NV149, had been identified. In the present study, this locus was mapped to 6q24. The nearest gene was found to be the cell-cycle control gene, ZAC. Monallelic expression of ZAC from the paternal allele only was demonstrated in a range of fetal tissues. ZAC may possess a dual role in disease, such that upregulation by paternal duplication or paternal uniparental disomy of chromosome 6 results in transient neonatal diabetes mellitus (TNDM), whereas loss or down regulation of ZAC results in a loss of cell cycle control, and hence tumorigenesis. Through analysis of a panel of B cell lymphomas, evidence was found for hypermethylation of the NV149 CpG island, which may be one mechanism through which expression of ZAC is lost in tumours.
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Mancini, DiNardo Debora. "Methylation-mediated inactivation of tumour suppressor genes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0021/NQ58149.pdf.
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Patel, Anjla Chhotubhai. "The role of fat tumour suppressor gene." Thesis, University of Cambridge, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619808.
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Marcar, Lynnette Nongkynrih. "Inhibition of p53 tumour suppressor function by tumour associated MAGE-A proteins." Thesis, University of Dundee, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.521696.
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Burns, Alice Sin Ying Wai. "The role of the p53 tumour suppressor pathway in central primitive neuroectodermal tumours." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300357.
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Wang, Yemin. "Role of tumour suppressor ING3 in melanoma pathogenesis." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/3850.
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The type II tumour suppressor ING3 has been shown to modulate transcription, cell cycle control, and apoptosis. To investigate the putative role of ING3 in melanoma development, we examined the expression of ING3 in 58 dysplastic nevi, 114 primary melanomas, and 50 metastatic melanomas with tissue microarray and immunohistochemistry. Overall ING3 was reduced in metastatic melanomas compared with dyslastic nevi and primary melanomas. Reduced nuclear ING3 staining also correlated with melanoma progression, increased cytoplasmic ING3 level, tumour location at sun-exposed sites, and a poorer disease-specific 5-year survival of patients with primary melanoma. Multivariate analysis revealed that nuclear ING3 staining can independently predict patient outcome in primary melanomas. In melanoma cells, ING3 expression was rapidly induced by UV irradiation. Using stable clones of melanoma cells overexpressing ING3, we showed that ING3 significantly promoted UV-induced apoptosis. Unlike its homologues ING1b and ING2, ING3-enhanced apoptosis upon UV irradiation was independent of functional p53. Furthermore, ING3 did not affect the expression of mitochondrial proteins but increased the cleavage of Bid and caspases. Moreover, ING3 upregulated Fas expression and ING3-mediated apoptosis was blocked by inhibiting caspase-8 or Fas activation. Knockdown of ING3 expression decreased UV-induced apoptosis remarkably, suggesting that ING3 plays a crucial role in cellular response to UV radiation. To explore how ING3 is deregulated in advanced melanomas, we examined ING3 expression in metastatic melanoma cells and found that ING3 was downregulated due to a rapid protein turnover in these cells. Further studies demonstrated that ING3 undergoes degradation via the ubiquitin-proteasome pathway. We also demonstrate that ING3 interacts with the SCF (Skp1/Cul1/Roc1/Skp2) E3 ligase complex. Knockdown of Cul1 or Skp2 significantly stabilized ING3 in melanoma cells. In addition, lysine residue 96 is essential for ING3 ubiquitination as its mutation to arginine completely abrogated ING3 turnover and enhanced ING3-stimulatd apoptosis upon UV irradiation. Taken together, ING3 is deregulated in melanomas as a result of both nucleus-to-cytoplasm shift and rapid degradation. The level of ING3 in the nucleus may be an important marker for human melanoma progression and prognosis. Restoration of ING3 expression significantly sensitizes melanoma cells to UV radiation through the activation of Fas/caspase-8 pathway.
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Marston, Nicola Jane. "Mutational analysis of the tumour suppressor protein, p53." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387679.
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Zabkiewicz, Joanna. "In vivo modelling of tumour suppressor gene function." Thesis, Cardiff University, 2005. http://orca.cf.ac.uk/55388/.
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LKB1 has been implicated in a wide range of cellular functions and is associated with many potential substrates in in vitro studies, however the in vivo role of LKB1 remains unclear and its precise contribution to the prevention of intestinal tumours in the hereditary Peutz-Jegers syndrome is as yet uncharacterised. Conditional deletion of LKB1 in the murine small intestine resulted in significant disruption of intestinal homeostasis, particularly that of the differentiation process, suggesting LKB1 plays a key role in intestinal differentiation and it is loss of this function that predisposes to tumourigenesis
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HonoÌrio, Sofia Maria Santos Andrade. "Molecular characterisation of candidate 3p21.3 tumour suppressor genes." Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409070.
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Markham, Douglas James. "Acetylation control of the retinoblastoma tumour suppressor protein." Thesis, University of Glasgow, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433229.
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Natan, Eviatar. "Why the tumour suppressor p53 is a tetramer." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609555.
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Rohrig, A. E. "Role for tumour suppressor Merlin in gene expression." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1415770/.
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The tumour suppressor Merlin is mutated in the familial cancer syndrome Neurofibromatosis Type 2 (NF2) and in various sporadic tumours. Several lines of evidence show a role for Merlin in mediating contact-dependent inhibition of proliferation. Contact inhibition is essential for normal tissue homeostasis and its deregulation is a hallmark of cancer. Despite extensive efforts the mechanism underlying tumour suppression by Merlin remains elusive. A proteomics approach led to the identification of novel Merlin interacting proteins several of which are involved in gene expression, in particular transcription elongation, RNA processing and histone modifications, and are also deregulated in cancer. Among those are the RNA PolymeraseII-associated factor1 complex (Paf1C), CHD1, TAT-SF1 and spliceosome components. These interactions have been validated and mapped to Merlin’s FERM domain and loss-of-function Merlin mutations found in tumours invariably disrupt these interactions. The interaction of Merlin with the Paf1C is modulated by cell density and is required for Merlin’s tumour suppressor function. We find a remarkable case of tumour suppressor gene hypersensitivity in Merlin-deficient cells that correlates with Merlin’s ability to regulate gene expression. Using genome-wide expression profiling we identify a gene signature associated with growth arrest by Merlin expression that is consistent with Merlin’s role in mediating contact inhibition and suggests a role for Merlin in innate immunity and communication with the microenvironment. By integrating re-expression and knockdown gene signatures a core Merlin signature has been defined that correlates with NF2 mutational status and suggests differential drug sensitivities and potential therapeutic targets for treatment of NF2-related tumours. Using genome-wide occupancy analysis we identify a subset of genes where Merlin expression regulates association of the Paf1C with chromatin of coding regions. Some of these regulated genes are known target genes of YAP, the transcriptional co-activator of the Hippo tumour suppressor pathway. Although YAP expression rescues growth arrest by Merlin, Merlin can regulate expression independently of YAP. A model is proposed where Merlin functions parallel to YAP to regulate gene expression at the elongation level through the Paf1C.
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Shahid, Taha. "Structure and mechanism of the BRCA2 tumour suppressor." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/25538.
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Mutations in the human BRCA2 gene are a leading cause of susceptibility to breast, ovarian and prostate cancers. Its protein equivalent BRCA2, is the key mediator in repair of double-stranded DNA breaks and interstrand crosslinks - the most dangerous forms of DNA damage, via RAD51 effected homologous recombination. Thereby, preferably the sister chromatid, or homologous chromosome is utilised to drive the repair. Described here is the first structural and related mechanistic characterisation of full-length (384 kDa) BRCA2, and its complex with RAD51 and DNA. Electron microscopy reconstruction reveals that BRCA2 exists as a dimer in head-to-tail conformation, which binds two oppositely directed sets of RAD51 molecules. Single-stranded DNA (derived from exonucleolytic processing of double-strand breaks) binds BRCA2 along its long axis, such that one set of RAD51 monomers always binds thereon regardless of its binding polarity. These then self-assemble into RAD51-ssDNA nucleoprotein filaments that catalyse the main reaction, having been nucleated and primed for growth by BRCA2. In complementary work, it is shown that BRCA2 increases the frequency of RAD51-ssDNA filament formation, but does not impact filament length itself. It is also shown that BRCA2 initiates monodirectional (3'→5') extension of the RAD51 filament on single-stranded DNA from nucleation sites (thence at the 3' end). Furthermore, BRCA2 initiates such nucleations at multiple sites along individual ssDNA molecules, suggesting that these extend and merge into a single nucleoprotein filament, which would be most capable of catalysing the subsequent homologous pairing and strand exchange reactions. Together, the structures and biochemical data define the molecular mechanism via which BRCA2 orchestrates the formation of RAD51 nucleoprotein filaments, which constitute the central reaction intermediate in the repair of DNA double-strand breaks.
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Seng, Tzer Jing. "Identification of candidate tumour suppressor genes on chromosome 22 in central nervous system tumours." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615650.
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Fogel, Valentina. "Regulation of the tumour suppressor p53 by E2F-1." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409008.
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Bruce, Christopher Kenneth. "Investigations of putative tumour suppressor loci in human malignancy." Thesis, Keele University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394629.
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Garvin, Alexander. "Post-translational regulation of the tumour suppressor IRF-1." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/13893/.
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IRF-1 (Interferon Regulatory Factor 1) is a transcription factor first identified as a regulator of Interferon expression. Two decades after its discovery, IRF-1 has been shown to be involved in numerous other pathways including apoptosis, cell cycle regulation, DNA damage/repair, immune cell development and inflammation. Transcriptional regulation of IRF-1 by a number of external agents has been extensively studied, however almost nothing is known about the posttranslational regulation of IRF-1 activity. In this study IRF-1 is shown to be phosphorylated at Thr180 by GSK3β (Glycogen Synthase Kinase 3β). Phosphorylated Thr180 promotes interaction with the ubiquitin E3 ligase SCFFbxw7u, (Skp1-Cu11-Fbxw7α) which increases turnover of IRF-1 protein. Phosphorylation dependent ubiquitination of IRF-1 was confirmed, as substitution of Thr180 to alanine reduced IRF-1 ubiquitination and increased stability. Enhanced phosphorylation of IRF-1 (by increasing GSK3β expression) promotes increased ubiquitination/degradation. Transactivation of the TRAIL (TNFα Related Apoptosis Inducing Ligand) promoter by IRF-1 was found to be dependent on GSK3β phosphorylation of Thr180 by use of reporter assays and inducible expression of IRF-1 in breast cancer cell lines. Importantly IRF-1 activity on the TRAIL promoter is dependent on proper turnover by the UPS (Ubiquitin Proteasome System), as chemical inhibition of the proteasome, or reduction in IRF-1 ubiquitination reduced activity in reporter assays. This suggests that phosphorylation of IRF-1 by GSK3β acts as a destruction signal through association with SCFFbxw7a. This signal dependent turnover of IRF-1 is required for proper transcriptional activation of the TRAIL promoter.
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Al-Azraqi, Abdulla Ali. "The P53 tumour suppressor pathway in human ovarian carcinoma." Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264421.
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Burbidge, Owen David. "Developing nanobodies to stabilise the tumour suppressor protein p16INK4a." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/288375.
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The tumour suppressor protein p16INK4a (p16) is a cyclin-dependent kinase (CDK) inhibitor that plays a key role in the regulation of the cell cycle by controlling the progression of cells through the G1 to S phase transition. Dysregulation of the protein through deletion, silencing or mutation of the gene encoding p16 is implicated in a range of different cancers including melanoma, cervical and oesophageal to name a few. p16 is composed of four ankyrin repeats and it has a very low thermodynamic and kinetic stability and rapidly unfolds even in the absence of denaturants. This low stability means that the protein is highly vulnerable to point mutations, which can result in functional inactivation through a range of different mechanisms such as deletion of key binding contacts, disruption of secondary or tertiary structure and consequent destabilisation leading to unfolding or aggregation. Heavy-chain antibodies are a unique form of antibody devoid of light chains found in the serum of the Camelid family (camels and llamas). Despite the absence of light chains, heavy-chain antibodies have evolved to complement traditional antibodies and retain the full binding capacity seen in canonical IgG antibodies. The single variable domain, known as a nanobody, is, at 15 kDa, the smallest antigen binding fragment, a tenth the size of a standard IgG antibody. The small size and relative ease of production, coupled with an unusually high stability, makes nanobodies useful tools as biological reagents, crystallography chaperones and therapeutics. The research contained within this PhD looks at the development of nanobodies to target p16. By leveraging the high stability of selected nanobodies, the aim was to obtain binders that could stabilise and reactivate a range of unstable cancer-associated mutants. The initial stages of the project focused on generating and optimising the expression and purification of p16 constructs prior to immunisation of animals to raise nanobodies. A high-throughput approach was taken to generate forty-five different p16 constructs with a range of different solubility and purification tags. These constructs were assessed in a multi-factorial expression screen, which resulted in the identification of a p16 construct with a ten-fold improvement in soluble expression levels compared with previous studies. A range of biophysical techniques, including circular dichroism and chemical denaturation, were performed to characterise this protein fully prior to immunisation. The second part of this project utilised a phage display library of two immune nanobody libraries generated against p16 and a p16 variant stabilised by previously published second-site mutations. This process yielded a large number of diverse nanobodies. Biophysical characterisation of these nanobodies was first performed, and they were found to have a range of chemical and thermal stabilities. Assays were then developed to test the ability of the nanobodies to stabilise p16. Two nanobodies were found to dramatically stabilise wild-type p16, with an increase in stability of approximately 44 % and 60 %, respectively. Furthermore, these nanobodies were also able to stabilise a subset of cancer-associated point mutants. Although there are NMR structures of p16, as well as a crystal structure of p16 bound to CDK6, the resolution of is very low, most likely due to the high backbone flexibility of p16. The last part of the project aimed to obtain a higher-resolution structure of p16 by using the two stabilising nanobodies as crystallisation chaperones. The more stabilising of the two nanobodies resulted in crystals that diffracted to a resolution of less than 2 $\AA$, a significant improvement compared with the previously published structure. In conclusion, a number of nanobodies were generated against tumour-associated p16 and shown to be capable of stabilising p16, allowing structure determination to high resolution and restoration of the stability of cancer-associated mutants to wild-type levels. In the project, a range of different approaches for nanobody production were explored, and these will be important for future applications. Moreover, the crystal structure of the p16-nanobody complex showed that the nanobody binds on the opposite face of p16, to the face involved in binding to CDKs; thus, this nanobody could potentially be exploited as a pharmacological chaperone to stabilise and restore the activity of cancer-associated mutant p16 in the cell.
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Woodward, Emma Roisin. "Molecular genetic studies of the VHL tumour suppressor gene." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624312.
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Bhullar, Punamdip Kaur. "Egr2/Egr3 are essential tumour suppressor genes for lymphomagenesis." Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/8319.
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Non-Hodgkin’s lymphoma is the fifth most common cancer in the UK, accounting for 4% of all new cases. The control of lymphomagenesis still remains a challenge. Early growth response gene (Egr) 2 and 3 are zinc finger transcription factors. Egr2 plays an important role in the development of both central nervous system and lymphocytes. However the mechanism of action in lymphocytes is still unknown. In order to fully understand the function of Egr2, in lymphocytes, we developed Egr2 and 3 double knockout mice (Egr2-/-Egr3-/-) by crossbreeding lymphocyte specific Egr2 knockout mice (CD2-Egr2-/-) with Egr3 knockout mice (Egr3-/-), as previous reports suggested that Egr3 compensates for the role of Egr2. In the absence of Egr2 and 3, the homeostasis of T cells is dysregulated with hyper-homeostatic proliferation of effector like phenotype cells. More importantly the development of spontaneous B and T cell lymphoma was found in more than 70% of Egr2-/-Egr3-/- mice. The lymphoma cells from Egr2-/-Egr3-/- mice were highly proliferative and metastatically spread into other non-lymphoid organs, such as lung, liver and kidney. In additional to this lymphoma development the Egr2-/-Egr3-/- mice showed signs of chronic inflammatory disorder. This inflammatory disorder was characterised by glomerulonephritis and an increase in serum cytokines, which may provide the microenvironment for the lymphoma development. To explore the molecular mechanism of tumour development in Egr2-/-Egr3-/- mice, the transcriptional profile of Egr2 was studied by microarray and ChIP-on-chip. We found firstly that Egr2 directly binds to the promoter regions of Ikaros and FOXO3. The deletion of Egr2 and 3 in lymphocytes led to the downregulation of Ikaros, Aiolos and FOXO3 expression. The impaired expression was found to be associated with proliferative disorder and the development of T and B cell lymphoma. Secondly Egr2 strongly inhibits STAT3 transcriptional activity by regulating SOCS3, which is a known inhibitor of STAT3. The breakdown of this regulation could be an important mechanism in lymphomagenesis. A model is proposed which defines Egr2 and Egr3 as the backbone of important tumour suppressor genes that control cell fate decision and regulates homeostasis in the lymphoid system. Thus, our results suggest that Egr2 and 3 are important regulators of lymphocyte function by their involvement in multiple cell signalling pathways, which could potentially be key genes for future cancer therapy.
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Zeqiraj, Elton. "Structure of the LKB1-STRAD-MO25 tumour suppressor complex." Thesis, University of Dundee, 2009. https://discovery.dundee.ac.uk/en/studentTheses/eb957e54-7f2a-4d08-ba2b-7838d71c25b9.
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A landmark study published over ten years ago established a link between mutations of the LKB1 gene and the Peutz-Jeghers cancer syndrome. Since then, much effort has been devoted to understanding the functional roles of the protein encoded by the LKB1 gene. LKB1 is a Ser/Thr kinase that is activated by binding to the pseudokinase STRAD and the scaffolding protein MO25. LKB1 activates AMPK and twelve other members of the AMPK family of kinases, thus controlling cellular energy and cell polarity. Much attention has been focused towards protein kinases activated by LKB1, although the mechanism by which STRAD and MO25 activate LKB1 remains unknown. The work described in this thesis was conducted with the aim of understanding the interactions of LKB1 with STRAD and MO25, and the mechanisms by which the latter two activate LKB1. I have tried to accomplish these aims using a structural biology approach. In chapter III of this thesis I show the structure of the regulatory STRAD /MO25 complex, and in chapter IV the structure of the heterotrimeric LKB1/STRAD /MO25 complex. The structure of STRAD reveals for the first time the determinant features of kinase inactivity, and provides an example of how pseudokinases can exert their functions through their conformation rather than phosphorylation. STRAD adopts a closed conformation typical of active protein kinases, and binds LKB1 as a pseudosubstrate. STRAD binding promotes the active conformation of LKB1, which is further stabilised by MO25 interacting with the LKB1 activation loop. This represents a previously undescribed mechanism of kinase activation that may be relevant to understanding the evolution of other pseudokinases. Finally the structure of the LKB1 heterotrimer reveals how mutations found in Peutz-Jeghers syndrome and other cancers impair LKB1 function.
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Crosland, Rachel. "Studies of the PTEN tumour suppressor in endometrial cancer." Thesis, Sheffield Hallam University, 2004. http://shura.shu.ac.uk/19515/.
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Somatic mutations in the PTEN gene (Phosphatase and Tensin Homologue Deleted on Chromosome Ten) have been found in many types of cancer, but most frequently in cancer of the endometrium. The PTEN gene encodes a D3 lipid phosphatase of the second messenger phosphatidylinositol 3,4,5-trisphosphate (PIP3), which activates protein kinase B/Akt. Constitutive activation of Akt has been found in cells that lack functional PTEN, thus by dephosphorylating PIP3, this enzyme modulates several cellular functions e.g. proliferation, differentiation and migration. The PTEN protein comprises a 403 amino acid, 55KDa protein which is present in the cytoplasm but has also been detected in the nucleus of some cells. The function of nuclear versus cytoplasmic PTEN has not yet been determined. Little is known about modulation of PTEN expression by molecules such as hormones and cytokines. It has been reported, however, that NGF, BDNF and vitamin D3 analogues can up-regulate PTEN. The steroid hormones oestrogen and progesterone have been proposed as mediators of PTEN transcription, since their expression in endometrium reflects the menstrual cycle. The role of TGF-beta1 in PTEN expression of PTEN in human cells has been also investigated, but the results are contradictory. Compounds which stimulate up-regulation of PTEN represent potential anti-tumour therapies and therefore merit investigation. To further investigate the role of PTEN in endometrial cancer the following approaches were taken. The effect of TGF-beta1 on two endometrial carcinoma cell lines, HEC-1B and Ishikawa were investigated. The cell lines were stimulated with TGF-beta1 in the presence or absence of serum, and changes in mRNA and protein levels of PTEN and other genes analysed by RT-PCR and Western blotting. The morphology, cell number and cell viability were also assessed. Modest up-regulation of PTEN mRNA was detected in both cell lines, but little change in protein levels was observed. In accordance with published data, TGF-beta1 suppressed the growth of, and changed the morphology of both cell lines. To study PTEN sub-cellular localisation, full-length human PTEN cDNA was used in RT-PCR to generate a 1.2Kb fragment which was cloned into a green fluorescent protein expression vector pEGFP-N1 to create pRC-2. Sequencing of pRC-2 confirmed the in-frame cloning of wild-type PTEN. Lipid-basedtransfection was used to transiently transfect HEC-1B, Ishikawa and Cos-7 cells. Strong perinuclear and cytoplasmic localisation was detected in these cell lines, and localisation to the endoplasmic reticulum was observed. Stimulation with TGF-beta and 17-beta-estradiol had no discernable effect on sub-cellular localisation of PTEN in either HEC-1B or Ishikawa cell lines. A mutational study was performed using a large repository of archival endometrial carcinomas and normal cervical controls. PCR was used to amplify PTEN exons 5 and 8 from extracted DNA and the fragments separated by single-strand conformation polymorphism (SSCP) analysis. A number of samples exhibiting bandshifts were detected in both exons.
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Milner, Ben J. "The role of tumour suppressor genes in ovarian cancer." Thesis, University of Aberdeen, 1993. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU555006.
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The role of tumour suppressor genes, in particular p53 and DCC, was investigated in human ovarian cancer. p53 codes for a DNA-binding nuclear phosphoprotein whose expression, in the wild-type form, is essential in the control of the cell cycle. Loss of function of this gene by mutation allows unrestrained cell proliferation to occur. The function of the DCC gene is not yet fully understood. A total of 29 malignant epithelial ovarian tumours, 15 of borderline malignancy, and 12 benign tumours were collected for study. Allele loss analysis confirmed that deletion of the p53 and DCC genes had occurred in 40&'37 and 41&'37 of the malignant tumours respectively. Two additional regions of loss were also identified at 17p13.3 (63&'37 ) and 17q23-qter (83&'37 ). Using SSCP analysis and direct DNA sequencing of exons 5 to 8, 52&'37 of the malignant tumours studied were found to have a p53 mutation. No mutations were found in any of the borderline or benign tumours. Immunocytochemical analysis of tissue sections from each of the tumours demonstrated that p53 over-expression had occurred in 55&'37 of the malignant tumours studied, and also in one of the borderline tumours. In total, 66&'37 of the malignant tumours were shown to have a p53 abnormality with either a mutation and/or protein over-expression. No correlation was found between any of the molecular abnormalities and either FIGO stage, the histopathological type of tumour, or the degree of tumour cell differentiation. However, a strong correlation was found between DCC allele loss and p53 mutation, and five out of six of the women whose tumours had both of these abnormalities died between 10 and 48 months after initial diagnosis. Finally, linkage analysis was carried out on a large breast/ovarian cancer family and it was confirmed that neither a mutation in the p53 gene nor a mutation in the DCC gene were responsible for the inherited predisposition to cancer.
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Svärd, Jessica. "Repressing the hedgehog signalling pathway : functional analysis of the tumour suppressors patched1 and suppressor of fused /." Stockholm : Karolinska institutet, 2007. http://diss.kib.ki.se/2007/978-91-7357-380-1/.
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McKenna, Sarah Mary Michelle. "The role played by BRCA1 in mediating the cytotoxic effect of antimicrotubule agents." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246470.
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Asimakopoulos, Fotios A. "Molecular analysis of chromosome 20q deletions associated with myeloproliferative disorders and myelodysplastic syndromes." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388490.
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Chinswangwatanakul, Wimol. "Role of p16 in chronic myeloid leukaemia and normal haemopoiesis." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313953.
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Jowsey, Paul Andrew. "The role of poly(ADP-ribose) polymerase-1 in the MDM2-p53 DNA damage response pathway." Thesis, University of Newcastle Upon Tyne, 2003. http://hdl.handle.net/10443/1005.
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p53 is a tumour suppressor protein that is stabilised and activated by DNA damage. DNA damage-induced p53 is able to bring about either cell cycle arrest or apoptosis by the induction of p53-responsive genes such as mdm2 and p21 waf-I. Mdm2 regulates p53 function by blocking the transcriptional transactivation domain of p53 and also by targeting p53 for degradation via an ubiquitin-mediated pathway. Increases in the levels and activity of p53 are brought about by post-translational modifications. The most widely studied modification of p53 is phosphorylation, mediated by several DNA damageactivated kinases. Poly(ADP-Ribose) Polymerase-l (PARP-l) is also a DNA damageactivated enzyme which covalently modifies several target proteins by poly(ADPribosylation). It is well established that PARP-1 plays a key role in DNA base excision repair. More recently, several studies have implicated PARP-1 in the regulation of p53 function in response to DNA damage, although the nature of this relationship has been controversial. This study aimed to clarify and investigate further the role of PARP-1 in p53 regulation using PARP-1 proficient and PARP-1 deficient mouse embryonic fibroblasts (MEFs) as well as a novel potent PARP-1 inhibitor (AGI4361; Ki < 6nM). In this study, both primary and immortalised PARP-l MEFs were used. Initial experiments revealed a tendency for PARP-l +/+ MEFs to develop p53 mutations during immortalisation. Interestingly. PARP-1 -/- MEFs retained wild-type p53, suggesting that the absence of PARP-l bypasses the requirement for p53 to be mutated during the immortalisation of MEFs. As these cells could not be used to analyse p53 responses, experiments were perfonned on primary PARP-l MEFs. However. the primary PARP-l- - MEFs were found to grow very slowly compared to their PARP-1 proficient counterparts. Interestingly. treatment of primary PARP-1+1+ MEFs with AG14361 had a similar effect on cellular growth. This growth inhibition in the absence of PARP-1 was only evident in primary and not immortalised cells. It was therefore decided to stably transfect immortalised PARP-l-- MEFs, expressing wild-type p53, with a plasmid construct containing PARP-l to produce an isogenic cell line pair. These cells have been used, together with a human colorectal carcinoma cell line (HCT-116) and the potent PARP-1 inhibitor AG14361 to analyse the p53 response to different DNA damaging agents. In response to ionising radiation and ultra violet radiation, the absence of PARP-1 did not alter the induction or activity of p53. In response to the alkylating agent temozolomide, treatment of PARP-l proficient MEFs with AG14361 potentiated the increase in p53 protein levels without affecting the transcriptional transactivation activity of p53, possibly due to an impaired repair of the DNA damage and hence increased signalling to p53 due to the persistence of DNA strand breaks. However, similar results were not obtained in the absence of PARP-1 protein (P ARP-1-/- MEFs) or in HCT -116 cells treated with AG 14361 The data presented do not support the hypothesis that PARP-1 is directly involved in the DNA damage induced regulation of p53. There may, however, be an altered p53 response in the absence of PARP-l when cells are treated with particular DNA damaging agents, due to an impaired DNA repair pathway.
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Strickson, Amanda J. "Analysis of expressed sequence tags mapping to the critical region of the 5q syndrome." Thesis, Open University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250497.
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Andrews, H. N. "Role played by BRCA1 in regulating the interferon gamma mediated antiproliferative response." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269159.
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McWilliams, Stewart. "BRCA1 regulates the interferon gamma mediated antiproliferative response." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246464.
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Bright-Thomas, Rachel Marie. "Corrective gene therapy in a murine model of familial adenomatous polyposis : a study of the efficacy of gene transfer and the resultant phenotypic effects." Thesis, University College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274918.
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Schweighoffer, Edina. "The role of Syk protein tyrosine kinase in B cell development and function." Thesis, Open University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250493.
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Fidler, Carrie. "Molecular analysis of the 5q- syndrome." Thesis, Open University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338608.
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Gornall, Robert J. "TP53 polymorphisms and haplotypes in breast, cervical and ovarian cancer." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310562.
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Gallagher, Stuart John. "The Role of the p14ARF Tumour Suppressor in Promoting Apoptosis." Thesis, The University of Sydney, 2008. http://hdl.handle.net/2123/3597.
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The incidence of melanoma has risen dramatically during the past three decades, yet there has been little improvement in effective treatments for this intractable and aggressive disease. Melanoma tumours are notoriously resistant to apoptosis, a cell suicide program that is activated by most cancer therapies. This thesis explores the role of the melanoma susceptibility gene product p14ARF in promoting cell cycle arrest and apoptosis, in order to resolve the impact of this tumour suppressor in melanomagenesis and melanoma susceptibility. The p14ARF tumour suppressor gene is mutated in almost half of all cancers, and germline mutations in p14ARF confer a greatly increased risk of developing melanoma. The primary function of p14ARF is to relay oncogenic signals to p53, a central regulator of cellular response to stress. There is conflicting evidence regarding the role of p14ARF in promoting apoptosis. Much of the current evidence is based on murine studies, which may not translate accurately to humans due to important differences in animal physiology and the primary sequence and functions of the mouse and human ARF proteins. Furthermore, results from previous studies are often compounded by supra-physiological expression of p14ARF, and are complicated by the fact that p14ARF shares its genomic sequence with the p16INK4a tumour suppressor gene. This study demonstrates that p14ARF expression in human cancer and primary cell lines promotes rapid p53-dependent cell cycle arrest, rather than apoptosis. As p14ARF expression did not induce apoptosis, we investigated if p14ARF could modulate the sensitivity of a cell to apoptosis induced by cytotoxic agents. Using a p14ARF-inducible U2OS osteosarcoma cell line model, we examined the impact of p14ARF expression on the apoptotic response of the cell to a panel of thirteen cytotoxic agents. p14ARF expression increased apoptosis caused by a sub-set of agents, including trichostatin A, sodium butyrate, DRB, Adriamycin and UVB radiation. p14ARF-mediated chemosensitivity was p53- and caspase-dependent, and involved the loss of mitochondrial potential. While loss of mitochondrial potential was dependent on p53, it was not blocked by caspase inhibition, demonstrating that caspases play a role downstream of mitochondrial depolarisation. Inhibition of individual components of the apoptotic program showed that p14ARF-mediated chemosensitivity was not strictly dependent on the pro-apoptotic Bax or Fas proteins. We also investigated whether p14ARF could sensitise melanoma to chemotherapeutics in vivo. We investigated the expression level of p14ARF, p16INK4a and MITFm and mutation status of B-RAF, N-RAS and PTEN in melanomas from 30 patients that had undergone isolated limb infusion - a palliative therapeutic strategy that results in much higher response rates than systemic treatment. Expression of p14ARF did not predict response to the drugs actinomycin D and melphalan . Instead, high expression of p16INK4a and presence of activating N-RAS mutation were independent predictors of response to high doses of these chemotherapeutic drugs. This work suggests that p14ARF analogues may be beneficial adjuncts in cancer therapy, but are unlikely to be effective as single agents. Additionally, p14ARF mimetics will only be effective in tumours with intact p53 signalling. Melanomas frequently carry functional p53, and may be susceptible to this mode of treatment providing the apoptotic pathway downstream of p53 is intact or can be restored.
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Gallagher, Stuart John. "The Role of the p14ARF Tumour Suppressor in Promoting Apoptosis." University of Sydney, 2008. http://hdl.handle.net/2123/3597.
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Doctor of Philosophy (PhD)The incidence of melanoma has risen dramatically during the past three decades, yet there has been little improvement in effective treatments for this intractable and aggressive disease. Melanoma tumours are notoriously resistant to apoptosis, a cell suicide program that is activated by most cancer therapies. This thesis explores the role of the melanoma susceptibility gene product p14ARF in promoting cell cycle arrest and apoptosis, in order to resolve the impact of this tumour suppressor in melanomagenesis and melanoma susceptibility. The p14ARF tumour suppressor gene is mutated in almost half of all cancers, and germline mutations in p14ARF confer a greatly increased risk of developing melanoma. The primary function of p14ARF is to relay oncogenic signals to p53, a central regulator of cellular response to stress. There is conflicting evidence regarding the role of p14ARF in promoting apoptosis. Much of the current evidence is based on murine studies, which may not translate accurately to humans due to important differences in animal physiology and the primary sequence and functions of the mouse and human ARF proteins. Furthermore, results from previous studies are often compounded by supra-physiological expression of p14ARF, and are complicated by the fact that p14ARF shares its genomic sequence with the p16INK4a tumour suppressor gene. This study demonstrates that p14ARF expression in human cancer and primary cell lines promotes rapid p53-dependent cell cycle arrest, rather than apoptosis. As p14ARF expression did not induce apoptosis, we investigated if p14ARF could modulate the sensitivity of a cell to apoptosis induced by cytotoxic agents. Using a p14ARF-inducible U2OS osteosarcoma cell line model, we examined the impact of p14ARF expression on the apoptotic response of the cell to a panel of thirteen cytotoxic agents. p14ARF expression increased apoptosis caused by a sub-set of agents, including trichostatin A, sodium butyrate, DRB, Adriamycin and UVB radiation. p14ARF-mediated chemosensitivity was p53- and caspase-dependent, and involved the loss of mitochondrial potential. While loss of mitochondrial potential was dependent on p53, it was not blocked by caspase inhibition, demonstrating that caspases play a role downstream of mitochondrial depolarisation. Inhibition of individual components of the apoptotic program showed that p14ARF-mediated chemosensitivity was not strictly dependent on the pro-apoptotic Bax or Fas proteins. We also investigated whether p14ARF could sensitise melanoma to chemotherapeutics in vivo. We investigated the expression level of p14ARF, p16INK4a and MITFm and mutation status of B-RAF, N-RAS and PTEN in melanomas from 30 patients that had undergone isolated limb infusion - a palliative therapeutic strategy that results in much higher response rates than systemic treatment. Expression of p14ARF did not predict response to the drugs actinomycin D and melphalan . Instead, high expression of p16INK4a and presence of activating N-RAS mutation were independent predictors of response to high doses of these chemotherapeutic drugs. This work suggests that p14ARF analogues may be beneficial adjuncts in cancer therapy, but are unlikely to be effective as single agents. Additionally, p14ARF mimetics will only be effective in tumours with intact p53 signalling. Melanomas frequently carry functional p53, and may be susceptible to this mode of treatment providing the apoptotic pathway downstream of p53 is intact or can be restored.
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McArdle, Stephanie. "p53 epitopes as potential tumour targets for immunotherapy programmes against cancers." Thesis, University of Sheffield, 2000. http://etheses.whiterose.ac.uk/14459/.
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The tumour suppressor gene p53 is pivotal in the regulation of program cell death (apoptosis), and point mutations within the gene represent the most common genetic alterations in human cancers. This process can result in the overexpression and/or accumulation of mutated and/or wild-type p53 protein within the cell. Cytotoxic T lymphocytes (CTL) play a critical role in the immune defense by recognising peptide/MHC complexes on the surface of virally infected or tumour cells followed by lysis. Therefore, p53-derived peptides are potential candidates for immunisation strategies designed to induce anti-tumour CTL in patients.
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Gaentzsch, Peer Christian. "The role of the human tumour suppressor CYLD in Drosophila." Thesis, University of Oxford, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491496.
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The cylindromatosis gene cyld encodes a tumour suppressor that is mutated in tumours of human skin appendages (cylindromas). Cell culture studies have shown that the CYLD protein is a deubiquitinating enzyme, which negatively regulates NF-KB and JNK signalling in mammals. Despite extensive research in the past few years, its developmental and physiological functions as well as its rolein tumourigenesis remain poorly understood. To further the understanding of the in vivo functions of CYLD, its Drosophila homologue dCYLD was investigated in an effort to establish a simpler and genetically tractable animal model. dCYLD also has deubiquitinating enzymatic activity, is broadly expressed during development and can be found in a wide range of adult tissues. My results demonstrate that dCYLD inhibits the Imd pathway, a Drosophila NF-KB-like signal transduction pathway. During pupal development, this regulative function seems to limit the release of Eiger, a TNF-like ligand triggering the Drosophila JNK pathway. Correspondingly, dCYLD deficiency is associated with conditional lethality of pupae due to JNK activation by Eiger.. Furthermore, dcyld homozygotes exhibit a pronounced susceptibility to infection with both Gram(-) and Gram(+) bacteria. Other phenotypes include altered fat body morphology and increased triglyceride levels. These results indicate that dCYLD is involved in a broad range of functions, highlighting its importance in the control of transcriptional regulation by NF-KB. In addition, its mechanistically novel role in the regulation of JNK pathway activation may provide new insights into the genesis of human cylindromas.
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Tang, Kit Shing. "Stability, folding and evolution of the tumour suppressor protein p16." Thesis, University of Cambridge, 2001. https://www.repository.cam.ac.uk/handle/1810/251785.
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Khoo, Kian Hoe. "Thermodynamic analysis of the stability of the tumour suppressor, p53." Thesis, University of Cambridge, 2010. https://www.repository.cam.ac.uk/handle/1810/252185.
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Duarte, Antonio. "Regulation of gene expression by the Wilms' tumour suppressor, WT1." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389178.
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Jones, Rebecca May. "Regulation and function of the INK4a/ARF tumour suppressor locus." Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1444810/.
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The CDKN2a locus encodes two important tumour suppressors, pl61NK4a and ARF. The two genes share a common exon which is translated in different reading frames. pl6,NK4a binds to CDK4 and CDK6, preventing them from forming active complexes with D cyclins. As a result, pRb does not undergo the phosphorylation necessary for the transition from the G1 to S phase of the cell cycle. ARF inhibits the ubiquitination of p53 by MDM2, thereby causing the accumulation of p53. There is a growing awareness that the CDKN2a locus plays a central role in the cellular defences against transformation, and in the cellular response to stress. For example, pl6INK4a is involved in senescence, a permanent cell cycle arrest triggered in primary human fibroblasts in response to many stresses, including the overexpression of oncogenes. However, little is known about the regulation of pl6INK4a under these circumstances, and work in this thesis investigates this issue using overexpression of Myc as a model. The thesis also describes the characterisation of human diploid fibroblasts (Milan cells) from a patient homozygous for the R24P mutation of pl6INK4a. As this mutation is in exon la, ARF is unaffected. The mutant pl6INK4a cannot bind to CDK4, but retains some capacity to bind to CDK6. Milan cells have also been used in combination with shRNA targeting ARF to investigate the relative roles of pl6INK4a and ARF in the prevention of transformation. A panel of Milan cells were produced expressing telomerase, with combinations of Myc, Ras and shRNA targeting ARF, and the ability of the cells to grow in soft agar was assessed. A similar panel of Milan expressing p53 shRNA was also built up. These cells were used to investigate whether ablation of ARF can substitute for the loss of p53 function often associated with transformation, and to help identify which aspects of the p53 pathway are activated in the defence against transformation.
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Narayan, Nisha. "Functional regulation of the Discs Large Tumour Suppressor by phosphorylation." Thesis, Open University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495581.
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The human homologue of the Drosophila Discs Large Tumour suppressor, hDlg, has been subject to various speculations concerning its role in the cell, with studies indicating roles in establishing and maintaining cellular polarity, as well as in controlling cell proliferation. The biochemical mechanism by which it might act in executing either function have, however, remained ambiguous. In this study we show that phosphorylation is a major posttranslational modification of the protein, affecting both location and function. We show that hDlg is phosphorylated both by the MAPKs and the CDKs, and both groups of kinases affect different aspects of the protein's behaviour. Post osmotic shock, the phosphorylation of hDlg by JNK leads to its accumulation in vesicular structures which we identify as endosomes, while its phosphorylation by the p38 MAPK in addition to relocating it to sites of cell-cell contact, also makes it more susceptible to degradation by the HPV18 E6 oncoprotein. Secondly, we show that hDlg is differentially regulated during the cell cycle, with each stage of the cell cycle leading to a different localisation of the protein, including its accumulation at the mitotic spindle in the M phase, as well as at the midbody during cytokinesis. We show also that the protein is phosphorylated by the Cyclin Dependent Kinases (CDK) 1 and 2, in a cell-cycle dependent manner on two sites - serine 158 and serine 442, and that these phosphorylations render the protein more stable and less susceptible to ubiquitination. Finally we show that hDig phosphorylated on serine 158 and on serine 442 is largely nuclear, and that both the HPV18 E6 and the HPV16 E6 oncoproteins, target this nuclear form for degradation. These findings help us understand the processes that regulate hDlg and how these modifications of the protein might contribute to its growth-regulatory function in the cell.
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Martin, Rosalind J. L. "Mapping of putative tumour suppressor genes in epithelial ovarian cancer." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287363.
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Brandt, Tobias. "Molecular mechanisms of DNA recognition by the tumour suppressor p53." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609611.
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