Secreted frizzled-related protein 4 inhibits proliferation and metastatic potential in prostate cancer

BACKGROUND: Secreted frizzled-related proteins (sFRP4) inhibits Wnt signaling and thus cellular proliferation in androgen-independent prostate cancer cells in vitro. However, increased expression of membranous sFRP4 is associated with a good prognosis in human localized androgen-dependent prostate cancer, suggesting a role for sFRP4 in early stage disease. Here, we investigated the phenotype of sFRP4 overexpression in an androgen-dependent prostate cancer model. METHODS: An sFRP4-overexpressing androgen-dependent (LNCaP) prostate cancer model was established to assess changes in cellular proliferation, the expression, and subcellular localization of adhesion molecules and cellular invasiveness, and compared with the findings in sFRP4-overexpressing androgen-independent cells (PC3). RESULTS: sFRP4 overexpression in both cell line models resulted in a morphologic change to a more epithelioid cell type with increased localization of b-catenin and cadherins (E-cadherin in LNCaP, N-cadherin in PC3) to the cell membrane. Functionally, sFRP4 overexpression was associated with a decreased rate of proliferation (P=0.0005), ßdecreased anchorage-independent growth (P<0.001), and decreased invasiveness in PC3 cells (P