Pin1 promotes prostate cancer cell proliferation and migration through activation of Wnt/β-catenin signaling

Recent evidence suggests that the peptidyl-prolyl isomerase Pin1 is an oncoprotein that acts as a novel therapeutic target in a variety of tumors. In this study, we investigated the clinical significance of Pin1 and its function in prostate cancer (PCa) tumor progression. Immunohistochemical and quantitative RT-PCR analyses were performed to detect the expression of Pin1 in 86 PCa tissue samples. The functional role of Pin1 was evaluated by small interfering RNA-mediated depletion in PCa cells followed by analyses of cell proliferation and migration. Furthermore, the association between expression of Pin1 and levels of beta-catenin and cyclin D1 was also evaluated. Our results showed that the high expression of Pin1 staining was 66 of 86 (76.74 %) PCa samples, and in 25 of 86 (29.07 %) BPH tissues, the difference was statistically significant (P < 0.001). Pin1 was significantly elevated in all PCa cell lines when compared to the normal RWPE-1 cells. We observed that proliferation and migration of LNCaP cells were inhibited by Pin1 knockdown. The levels of beta-catenin and cyclin D1 in clinical PCa specimens were positively associated with Pin1 expression. Our results suggest that Pin1 plays an important role in tumorigenesis of PCa, suggesting that targeting Pin1 pathway could represent a potential modality for treating PCa.