Objective       To investigate the effect of genistein (GEN) and daidzein (DAI) on apoptosis in human prostate cancer DU-145 cells and their correlation with peroxisome proliferators-activated receptor γ(PPARγ).       Methods        PPARγ activity in prostate cancer DU-145 cells treated with soy isoflavones was mea-sured by peroxisome proliferator responsive element (PPRE)-driven luciferase reporter gene assay. DU-145 cells were respectively treated genistein and daidzein alone and either of them combined with GW9662

which was a selective inhibitor of PPARγ

for 48 h. The expression and distribution of PPARγ were detected by immunofluorescence staining. Cell apoptosis was determined by TUNEL assay and AnnexinⅤ/PI dual-color flow cytometry.       Results       Genistein and daidzein significantly enhanced luciferase expression activity in DU-145 cells transfected with PPRE-TK-Luc plasmid

and the effect could be reversed by GW9662. The changes of PPARγ expression in DU-145 cells were not significant after treatment with either genistein or daidzein

but PPARγ translocation to nucleus increased. The apoptotic rate of DU-145 cells treated with genistein or daidzein increased significantly (P0.05). When cells were treated with either genistein or daidzein combined with GW9662

the increased apoptosis rate and PPARγ nucleus translocation were significantly inhibited.       Conclusion       Soy isoflavones promote apoptosis in human prostate cancer DU-145 cells through PPARγ activation.