Prostate cancer is the 2nd most prevalent cancer in men and has poor outcome when patients progress from localised disease to metastatic castrate resistant prostate cancer (mCRPC). Intratumoural hypoxia features across multiple cancer types and in prostate cancer associates with local recurrence, metastasis, androgen independence and neuroendocrine differentiation. Crucially, hypoxia and genomic instability have an independent and additive effect on biochemical relapse in patients with localised tumours. Bioinformatic analysis and functional pre-clinical work suggests an association between hypoxia and genomic alterations which could be driven by DNA repair dysfunction. However, the relative contribution of hypoxia associating with vs driving genomic instability is still poorly understood. This PhD investigated hypoxia as a mechanistic driver of genomic instability in prostate cancer. In-vitro work revealed hypoxic suppression of homologous recombination (HR) was dependent on cell density. In the SV40 immortalised PNT2 cell model, supra chronic hypoxic exposure (20 generation doublings, 20#G) was required to observe HR factor suppression in logarithmically growing cells. This conferred sensitivity to poly (ADP) ribose polymerase inhibition (PARPi) but further work is required to confirm HR dysfunction in this model. Supra chronic hypoxia drove copy number alterations (CNAs) in PNT2 cells with unstable genomes, but not human telomerase reverse transcriptase (hTERT) immortalised prostate epithelial cells (PrECs) with stable genomes. Hypoxia induced genomic instability increased genomic and phenotypic heterogeneity in PNT2 cells. This could be important in the clonal evolutionary trajectory of prostate tumours. For the first time this PhD provides data showing heterogeneity of spatial hypoxia-HR relationships in primary prostate tumours. An integrated spatial transcriptome/proteome workflow was developed to further characterise wider expressivity across hypoxic gradients. This multi-omics approach provides a platform for future clinical work investigating hypoxia. Overall, this work outlines a mechanistic basis for the adverse prognosis seen in patients whose tumours have hypoxia and genome instability, and fresh evidence for stratification and treatment intensification of localised prostate cancer patients with hypoxic tumours.
Date of Award | 31 Dec 2022 |
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Original language | English |
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Awarding Institution | - The University of Manchester
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Supervisor | Iain Hagan (Supervisor) & William Newman (Supervisor) |
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- Hypoxia
- Homologous recombination
- Spatial transcriptomics
- Genomic instability
- Prostate cancer
- DNA repair
Mechanistic studies of hypoxia as a driver of genomic instability in prostate cancer
Ashton, J. (Author). 31 Dec 2022
Student thesis: Phd