TY - JOUR T1 - Involvement of the Estrogen Receptor β in Genistein-induced Expression of p21<sup>waf1/cip1</sup> in PC-3 Prostate Cancer Cells JF - Anticancer Research JO - Anticancer Res SP - 709 LP - 714 VL - 28 IS - 2A AU - KENTARO MATSUMURA AU - TOMOAKI TANAKA AU - HIDENORI KAWASHIMA AU - TATSUYA NAKATANI Y1 - 2008/03/01 UR - http://ar.iiarjournals.org/content/28/2A/709.abstract N2 - 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) β 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 ERβ in the PC-3 cells was assessed by quantitative real-time reverse transcription-PCR. ERβ 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 ERβ in the PC-3 cells. The siRNA against ERβ suppressed the genistein-induced expression of p21 and reduced the transactivation activity of the p21 promoter induced by genistein. Conclusion: ERβ is involved in genistein-induced expression of p21 in PC-3 cells. ER -