Background: Dietary genistein, a phytoestrogen derived from soybean, has been suggested as a chemopreventive agent for prostate cancer. Genistein has been reported to exert its anticancer effects via a variety of functional pathways, but the upstream signaling of molecules regulated by genistein remains unclear. In this study, estrogen receptor (ER) beta involvement in genistein-induced expression of cell cycle inhibitors in PC-3 prostate cancer cells was investigated.
Materials and methods: The proliferation of PC-3 cells exposed to genistein was measured by the water-soluble tetrazolium salt (WST-1) proliferation assay. The expression of p21, p27 and ERbeta in the PC-3 cells was assessed by quantitative real-time reverse transcription-PCR. ERbeta silencing was performed using a small interfering RNA (siRNA). The transcriptional activity of the p21 promoter was determined by the luciferase reporter assay.
Results: Genistein caused marked inhibition of proliferative activity and induced the expression of p21 and ERbeta in the PC-3 cells. The siRNA against ERbeta suppressed the genistein-induced expression of p21 and reduced the transactivation activity of the p21 promoter induced by genistein.
Conclusion: ERbeta is involved in genistein-induced expression of p21 in PC-3 cells.