Clinical Significance of Wnt/beta-Catenin Signalling and Androgen Receptor Expression in Prostate Cancer

PURPOSE: To investigate the relationships among the Wnt/beta-catenin pathway, androgen receptor (AR), and clinicopathological factors in hormone-naive prostate cancer. MATERIALS AND METHODS: This study was conducted with132 cases of hormone-naive prostate cancer treated by prostatectomy and prostate needle biopsy. An immunohistochemical study using antibodies against beta-catenin, matrix metalloproteinase-7 (MMP-7), and the AR was performed. For the in vitro study, PC-3, LNCaP, 22Rv1, and DU145 cell lines were used. RESULTS: The clinical or pathological stage ware a localized cancer in 36 patients (27.3%), locally advanced cancer in 31 (23.5%), and metastatic cancer in 65 (49.2%). We detected increased beta-catenin, AR, and MMP-7 expression with a high Gleason grade, disease progression, and increasing serum prostate-specific antigen (PSA) levels (p<0.01). In Spearman's rank correlations, the expression of cytoplasmic beta-catenin, MMP-7, and the AR were found to be significantly positively correlated. In addition, the expression of beta-catenin, MMP-7, and the AR were significantly correlated with clinicopathological variables indicative of a poor prognosis. Forty-nine patients with primary androgen deprivation had short response durations from hormone therapy to PSA progression with elevated MMP-7 expression on the Kaplan-Meier curve (p=0.0036). CONCLUSIONS: These data show that an activated Wnt/beta-catenin pathway and AR expression in prostate cancer are correlated with metastasis and aggressiveness. In addition, the expression of MMP-7 protein, a target of the Wnt/beta-catenin pathway, is associated with PSA progression in prostate cancer patients undergoing primary hormone therapy.

Bone Morphogenetic Protein Signaling: Implications in Urology

The bone morphogenetic proteins (BMPs), as members of the transforming growth factor-beta (TGF-beta) superfamily, not only control bone formation, but also regulate multiple key steps during embryonic development and differentiation. Furthermore, BMPs play critical roles in maintaining the homeostasis of the cardiovascular, pulmonary, reproductive, urogenital, and nervous systems in adult life. Like all members of the TGF-beta superfamily, BMP signaling is mediated through a heteromeric complex of type I and type II transmembrane serine/threonine kinase receptors. The subsequent signal transduction cascade includes either the canonical Smad-dependent or non-canonical Smad-independent pathways. Reflecting the critical function of BMPs, BMP signaling is tightly regulated at multiple steps by various mechanisms including extracellular endogenous antagonists, neutralizing antibodies/extracellular soluble receptor domains, small molecule inhibitors, cytoplasmic inhibitory Smads, and transcriptional co-repressors. Recently, dorsomorphin, the first small molecule inhibitor of BMP signaling, was identified and suggested as a useful tool for dissecting the mechanisms of signaling pathways and for developing novel therapeutics for diverse human diseases that are related to the BMP signaling pathways. In this article, we discuss various mechanisms involved in regulating BMP signaling pathways and their implications for urology.