Increased plasma caveolin-1 levels are associated with progression of prostate cancer among Japanese men.

AIM Up-regulation of caveolin-1 (CAV1) is associated with aggressive prostate cancer. Among Caucasian and African-American patients, plasma CAV1 levels are elevated in patients with castration-resistant prostate cancer (CRPC), but not in those with hormone-sensitive prostate cancer (non-CRPC), which implies that CAV1 could be a therapeutic target for CRPC. Here, we evaluated associations between plasma CAV1 levels and these types of cancer in Japanese men, and CAV1 expression in PC3 (CRPC) and LNCaP (non-CRPC) cell lines. MATERIALS AND METHODS Plasma samples were obtained from 58 patients with prostate cancer: 36 with CRPC and 22 with non-CRPC. Enzyme-linked immuno sorbent assay (ELISA) kits were used to determine CAV1 plasma levels; qRT-PCR and western blots were used to evaluate the expression of CAV1 mRNA and protein in cell lines. RESULTS Plasma CAV1 levels in patients with CRPC were greatly higher than in those with non-CRPC (1.46±1.37 ng/ml in CRPC; 0.56±0.32 ng/ml in non-CRPC, p<0.004). Western blot and real-time qRT-PCR showed CAV1 protein and mRNA in PC3 cells to be significantly overexpressed compared to its expression in LNCaP cells (p<0.0001). CONCLUSION Our results showed a relationship between CAV1 expression and prostate cancer progression, and support the possibility of CAV1 as a therapeutic target for CRPC.