Genistein affects androgen-responsive genes through both androgen- and estrogen-induced signaling pathways.

This study examined the mechanisms by which the prostate cancer chemopreventive agent genistein modulates gene expression in LNCaP human prostate cancer cells. Expression of androgen- and estrogen-regulated genes was measured in LNCaP cells cultured in the presence or absence of hormonal stimulation and the presence or absence of genistein. Genistein strongly suppressed basal expression of androgen-responsive gene (ARG) mRNAs, including prostate-specific antigen (PSA) and Ste20-related proline-alanine-rich kinase (SPAK). However, genistein had little or no effect on basal expression of two other ARGs, beta2-microglobulin (B2M) or selenoprotein P (SEPP1). Culturing LNCaP cells in the presence of the synthetic androgen R1881-induced increases in PSA, SPAK, B2M, and SEPP1 mRNA levels. The R1881-induced expression of these genes was uniformly blocked by genistein. For PSA and SPAK, genistein also blocked or downregulated 17beta-estradiol-induced increases in mRNA expression. These results indicate that genistein selectively alters expression of ARG mRNAs in LNCaP cells through modulation of both androgen- and estrogen-induced signaling pathways. 2005 Wiley-Liss, Inc.