PectaSol-C Modified Citrus Pectin Induces Apoptosis and Inhibition of Proliferation in Human and Mouse Androgen-Dependent and- Independent Prostate Cancer Cells

Abstract

To demonstrate the efficacy of PectaSol-C modified citrus pectin (MCP) on prostate cancer in vitro. Cytotoxicity analysis of PectaSol-C was performed by MTT assay, as were parallel studies with the former brand version of MCP called PectaSol. Apoptosis and inhibition of cell growth were investigated by Western blotting. Androgen-dependent and -independent human prostate cancer cell lines (LNCaP and PC3, respectively), androgen-dependent and -independent murine prostate cancer cell lines (CASP2.1 and CASP1.1, respectively), as well as noncancerous human benign prostate hyperplasia BPH-1 cell line, were used in the study. MTT assay revealed that 1.0% PectaSol exerted cytotoxicity on LNCaP, PC3, CASP2.1, CASP1.1, and BPH-1 cells for 4-day treatment by 48.0% +/- 2.1%, 54.4% +/- 0.3%, 15.4% +/- 0.8%, 46.1% +/- 1.7%, and 27.4% +/- 1.6%, respectively; whereas 1.0% PectaSol-C showed cytotoxity by 52.2% +/- 1.8%, 48.2% +/- 2.9%, 23.0% +/- 2.6%, 49.0% +/- 1.3%, and 26.8% +/- 2.6%, respectively. Western blotting further confirmed that both MCPs inhibit MAP kinase activation, increase the expression level of its downstream target Bim, a pro-apoptotic protein, and induce the cleavage of Caspase-3 in PC3 and CASP1.1 prostate cancer cells. PectaSol MCP and PectaSol-C MCP can inhibit cell proliferation and apoptosis in prostate cancer cell lines. Our data suggested that 1.0% PectaSol-C can be used for further chemopreventive and chemotherapeutic analysis in vivo.