The AKR1C3/AR-V7 complex maintains CRPC tumour growth by repressing B4GALT1 expression.

ABSTRACT

Multiple mechanisms contribute to the survival and growth of metastatic castration-resistant prostate cancer (mCRPC) cells without androgen, including androgen receptor splice variants (AR-V) and de novo intratumoral androgen synthesis. AKR1C3 is a critical androgenic enzyme that plays different roles in mCRPC, such as an EMT driver or AR coactivator. However, the relationship and regulatory mechanisms between AKR1C3 and AR-V remain largely unknown. In this study, we observed a positive correlation between AKR1C3 and AR-V7 staining in tissues from prostate rebiopsy at mCRPC. Mechanistically, AKR1C3 interacts with AR-V7 protein in CRPC cells, which can reciprocally inhibit AR-V7 and AKR1C3 protein degradation. Biologically, this complex is essential for in vitro and in vivo tumour growth of CRPC cells after androgen deprivation as it represses B4GALT1, a unique tumour suppressor gene in PCa. Together, this study reveals AKR1C3/AR-V7 complex as a potential therapeutic target in mCRPC.