Introduction

1. No. 121 The role of hypoxia inducible factor 1α as a potential biomarker for the development and prognosis of castrate resistant prostate cancers W. K.B. Ranasinghe1,2, L. Xiao1, S. Kovac1, M. Chang1, A. Shulkes,1 D. Bolton1,2, G. Baldwin1,  O. Patel1 1Department of Surgery and 2Department of Urology, Austin Hospital/ University Of Melbourne, Heidelberg, VIC, Australia Introduction Failure of Androgen deprivation therapy (ADT) leads to the development of castrate-resistant prostate cancer (CRPC), lethal form of prostate cancer (PC) refractory to most chemotherapeutic agents. Currently there is no method to determine which PCs will progress to CRPCs. Hypoxia-inducible factor 1α (HIF1α) is a key transcription factor in cell-mediated adaptive response to changes in tissue oxygenation and is over expressed in many human cancers. • Results • CRPC cells (PC3 and DU145) have higher levels of basal HIF1α compared with androgen receptor positive(AR+ve) (LNCAP) cells, in vitro. • PC3 (CRPC) cells have better survival when exposed to cytotoxic conditions compared with LNCaP (AR+ve) cells but the survival advantage is lost when HIF1α is knocked down. • HIF1α over-expression may increase the metastatic potential of CRPC cells. • Presence of HIF1α was an independent risk factor for development of CRPC, progression to metastatic prostate cancer and PC-specific death after starting ADT, using a multivariate Cox Regression analysis, when adjusted for HIF1α status, Gleason score, Pre-interventional PSA and age. • Kaplan–Meier estimates of CRPC-free survival (Panel A), metastases-free survival (not shown) and prostate cancer specific survival (Panel B) in patients on ADT. • The diagnostic accuracy of HIF1α tumours in predicting development of CRPC, progression to metastatic prostate cancer and PC-specific death after starting ADT, all had sensitivities of 100% and negative predictive values of 100%, but the specificities were 23%, 25% and 23% respectively. Survival of HIF1α Knockdown PC3 cells Survival of PC Cells • Aim • We aimed : • to investigate the role of HIF1α in the regulation of CRPC and its characteristics of metastases and chemo-resistance • to analyse its potential as a biomarker for prediction of the • development of CRPC. Migration in HIF1α Knockdown PC3 cells Migration in PC Cells • Methods • In vitro • Three human prostate cancer cell lines (PC3, DU145 and LNCaP) were used. • Expression of HIF1α was examined by Western Blot. • Cell proliferation was measured by automated cell counter (Countess® Invitrogen) following different treatments. • Boyden chamber assays were used to study migration of PC cells. • Stable knockdown of HIF1α protein expression was attained using RNA interference (shRNA vector). • A hypoxia chamber was used to create a 1% O2 environment. • Human studies • 100 human prostate tumours were stained for HIF1α by immunohistochemistry. • The outcomes of CRPC, distant metastases and PC-specific deaths were measured. • One-way Anova, Univariate and Multivariate Cox regression analyses with Firth’s penalised maximum likelihood method, Kaplan Meier estimates were used for statistical analyses. A B • Conclusions • HIF1 α is likely to characterise the development of CRPC, metastatic potential and chemo-resistance in PC. • HIF1α could be used in conjunction with Gleason score to predict development and prognosis in CRPCs. • Targeted reduction of HIF1α in CRPCs could possibly improve prognosis by reducing chemo-resistance and tumour metastasis. Log Rank (Mantel – Cox) p =0.037 Log Rank (Mantel – Cox) p =0.016 Acknowledgements Carmel Murone, Lee Lewis from Vic Bio bank. Dr. Sandy Clarke from the Department of statistics, University of Melbourne. Poster presentation sponsor