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oai:figshare.com:article/32805878 2026-10-01T16:12:14Z portal_1172 item_type_8 month_year_10_2026

Identification of critical hypoxia-induced factors in prostate cancer treatment resistance Oloruntoba I Osagie (24292994) PUREID: 690051193 Prostate Cancer Castrate resistance prostate cancer androgen deprivation therapy (ADT) androgen receptor signalling Hypoxia Radiation CRISPR/Cas9 Whole Genome Screen Protein protein interactions Proximity labelling metastasic castrate resistant prostate cancer Prostate cancer (PCa) is the second leading cause of cancer-related death in men worldwide. Despite advances in androgen deprivation therapy (ADT) and radiation therapy, many tumours progress to castration-resistant prostate cancer (CRPC).m Tumour hypoxia further promotes therapeutic resistance and disease aggressiveness, yet the molecular mechanisms underlying adaptation to hypoxic stress remain incompletely understood. This thesis investigated how PCa cells respond to hypoxia (0.5% O2), ionizing radiation (IR; 1 Gy x 4 fractions), and androgen stimulation (R1881). A genome-wide CRISPR/Cas9 loss-of-function screen was performed in metastatic androgen independent DU-145 cells using the Brunello library (~76,000 sgRNAs). Under hypoxia, chromatin regulators and histone methyltransferases, including KMT2C, KMT2D and SMARCA4, were significantly depleted (FDR < 0.05), indicating enhancer-mediated transcriptional dependencies. Functional validation demonstrated that silencing KMT2C and KMT2D reduced survival by 40% under hypoxia but not normoxia. RNA-seq analysis revealed hypoxia-driven reprogramming of ribosomal, metabolic and stress-response pathways, consistent with activation of the integrated stress response (ISR). The IR screen identified DNA damage repair genes (e.g., PRKDC, XRCC4, NHEJ1) as major dependencies, while positively selected genes suggested adaptation. To complement this approaches, BioID-based proximity labelling coupled with mass spectrometry was performed in PC-3 cells expressing full length androgen receptor (AR-WT). This identified canonical AR cofactors (e.g., FOXA1, HOXB13, SWI/SNF complex) and stress-induced interactions, including RA1, PHF14, HMG20A and USP34. Collectively, this work provides a multi-omics framework integrating CRISPR and functional genomics, transcriptomics, and proteomics to identify chromatin and translational regulators as potential therapeutic targets and biomarkers of CRPC progression.<br><br><i>Thesis is embargoed until 31 July 2031.</i><br> 2026-10-01T16:12:14Z Text Thesis 10.17034/32805878.v1 https://figshare.com/articles/thesis/Identification_of_critical_hypoxia-induced_factors_in_prostate_cancer_treatment_resistance/32805878 All Rights Reserved Open Access after 2031-07-31