Endocrine Abstracts

Although new treatments for castrate-resistant prostate cancer (CRPC), such as enzalutamide and abiraterone, have shown promise, moderate response rates and development of resistance to these agents has limited their clinical effectiveness. It is therefore vital we improve our understanding of androgen receptor (AR) re-activation in advanced disease, focusing particularly on regulatory processes governing activity of AR mutants and splice variants (AR-Vs), to enable the development of patient-orientated treatments in CRPC. Our previous research utilising an AR replacement model in LNCaP cells demonstrated that the bicalutamide-activated AR_W741L mutant selectively regulates a gene-set distinct from endogenous AR_T877A offering new insights into discriminate functionality and opportunities for selective drug targeting of AR mutants. In order to enable more physiological modelling of aberrant AR activity, and to define their global transcriptome and cistrome, we are currently generating CRISPR-edited LNCaP and CWR22Rv1 cell lines expressing AR_W741L, and respective abiraterone- and enzalutamide-activated AR_H874Y and AR_F876L mutants. We have verified our designed sgRNA/Cas9 targeting AR exons 5 and 8 to enable knock-in mutations at positions W741 and H874Y/F876L, respectively in both cell lines. The activity of each AR mutation in the two cell lines will be assessed using (i) candidate AR target genes expression analysis, (ii) AR immunofluorescence and (iii) RNA- and chromatin immunoprecipitation sequencing. The expected outcomes for this project is to comprehensive profile aberrant AR signalling that is vital for therapeutic exploitation to ultimately benefit in advanced PC patients.

Presenting author: Wenrui Guo, Newcastle University Northern, Institute for Cancer Research, Paul O’Gorman Building, Medical School, Framlington place, Newcastle upon Tyne, NE2 4HH, UK. Email: [email protected].