Glycitein induces cellular differentiation in nontumorigenic prostate epithelial cells

Abstract

that increased consumption of soy is associated with a reduced risk for prostate cancer. Soy isoflavones are thought to be responsible, in part, for this anticancer activity. Soy isoflavones have been shown to induce cellular differentiation in a number of tissues. However, isoflavone-induced differentiation in the prostate has not been examined. The present study examined the effects of the soy isoflavone, glycitein, on luminal and basal cell differentiation in a nontumorigenic prostate epithelial cell line (RWPE-1). Differentiation was characterized by inhibition of cellular proliferation, cell cycle arrest, and cytokeratin expression. Cytokeratins are differentially expressed among epithelial cell types with luminal prostate epithelial cells expressing cytokeratins 8/18 while basal epithelial cells express cytokeratins 5/14. Treatment of RWPE-1 cells with the soy isoflavones genistein, daidzein, equol, and glycitein (0-50μM) significantly inhibited cellular proliferation at 50μM and glycitein inhibited cellular proliferation at 5 and 50μM. Expression cytokeratin 18 was increased upon treatment of RWPE-1 cells with with N-(4hydroxyphenyl) retinamide (4-HPR, 1μM), while glycitein treatment (50μM, 8 d) significantly reduced expression of this luminal marker. These data suggest that glycitein may induce basal cell differentiation in the RWPE-1 cell line. Maintaining the basal cell population within the prostate may represent a novel mechanism by which soy isoflavones reduce prostate cancer risk. ABSTRACT Elizabeth A. Clubbs and Joshua A. Bomser OSU Interdisciplinary PhD program in Nutrition, The Ohio State University, Columbus OH 43210, USA