Protocadherin-PC promotes androgen-independent prostate cancer cell growth

BACKGROUND. Protocadherin-PC (PCDH-PC) expression is upregulated in apoptosis-resistant sublines of the LNCaP human prostate cancer (CaP) cell line. Here, we assess the role of PCDH-PC in CaP cells and its mRNA expression in human prostate tissues. METHODS. LNCaP cells transfected with PCDH-PC were tested for their ability to grow in vitro and in vivo in androgen-deprived conditions. PCDH-PC mRNA expression was evaluated by semi-quantitative RT-PCR and by in situ hybridization. RESULTS. PCDH-PC expression induced Wnt signaling in CaP cells and permitted androgenin-dependent growth of hormone-sensitive CaP cells. Expression of PCDH-PC-homologous transcripts was low and restricted to some epithelial cells in normal tissue and to CaP cells in tumors. However, hormone-resistant CaP cells expressed significantly higher levels of PCDH-PC-related mRNA. CONCLUSIONS. Our findings suggest a novel mechanism for the progression of CaP involving expression of PCDH-PC. This novel protocadherin induces Wnt signaling, promotes malignant behavior and hormone-resistance of CaP cells.