Polycomb-mediated deactivation of AR-feedback loop leads to castration-resistant prostate cancer [gene expression]

Castration-resistant prostate cancer (CRPC) is a lethal disease, often characterized by aberrant androgen receptor (AR) activation independently of androgen. We have previously reported that AR can directly repress the expression of many target genes, one of which is NOV/CCN3. Here we show that NOV, primarily localized in the cytoplasm, physically interacts with AR at its Nterminus and sequesters AR and AR variants in the cytoplasm, thereby reducing AR chromatintargeting. This negative feedback loop, however, is disrupted in CRPC due to epigenetic silencing of NOV by the Polycomb group protein EZH2, rendering AR transcriptional activities and drug-resistant prostate cancer progression. Our findings thus suggest a working model wherein AR-repressed genes critically prevent CRPC through negative feedback loops inhibiting AR signaling. genetic_modification_design; gene expression of LNCaP or C42B cells