Prolylcarboxypeptidase as a Predictive Biomarker in Prostate Cancer

Abstract

Prolylcarboxypeptidase (PRCP) selectively targets specific substrates. It cleaves angiotensin II to generate angiotensin (1-7) and inactivates angiotensin III. Prostate tissues from patients with prostate cancer (PCa) show elevated PRCP expression and moderate cytoplasmic staining. Elevated levels of PRCP have been detected in carcinomas of the kidney, breast, and prostate. However, the detailed biological functions and link with the prostate cancer cells remain unclear. To evaluate the role of prostate PRCP, we characterized and measured the expression pattern and activity of PRCP in 22Rv1, LNCaP, DU 145, and PC3 and compared with RWPE-1 cells, as control. We optimized multiple steps of the protocol, e.g. cell number, cell viability, S-phase test, Hoechst 33258 staining, and quantification of amplified cDNA yields and final qPCR quantification, to quantify gene expression of Prcp gene in the PCa cell lines. The expression levels of PRCP was significantly elevated in LNCaP cells and 22Rv1. Accordingly, PRCP protein expression were increased in LNCaP cells and 22Rv1. PRCP protein expression and activity were reduced by PRCP-siRNA. We conclude from these data that increased PRCP abundance may be a feature of castration-resistant prostate cancer. Our findings shed new insight on PRCP function, and suggest that PRCP may have the potential to become useful target for the diagnosis and treatment of PCa.