OBJECTIVETo investigate the effect of tea polyphenols on the proliferation of human prostate cancer cells and its possible mechanism.

METHODSWe cultured androgen-independent prostate cancer DU145 cells in the medium with different concentrations (50, 100, 250 and 500 microg/ml) of tea polyphenols, and those in the normal medium as the control. After 48 hours of culture, we detected the survival rate of the cells by MTT assay and determined the expression of survivin by Western blot and quantitative RT-PCR.

RESULTSAt 48 hours, the survival rates of the prostate cancer DU145 cells were 0.97 +/- 0.12, 0.71 +/- 0.07, 0.20 +/- 0.03 and 0.08 +/- 0.01 in the 50, 100, 250 and 500 microg/ml tea polyphenols treatment groups, all significantly reduced as compared with the control group (P < 0.01) except that of the 50 microg/ml group (P = 0.42). Furthermore, the survival rate continued to decrease with the prolonging of time, dropping below 5% at 96 hours except in the 50 microg/ml group. The grey values of the survivin expression in the 100, 250 and 500 microg/ml tea polyphenols groups were 13 425 +/- 34, 2 017 +/- 24 and 1 274 +/- 22, respectively, at 48 hours, significantly lower than 15 075 +/- 48 in the control group (P < 0.01). Moreover, the content of survivin mRNA at 48 hours was markedly lower in the 50, 100, 250 and 500 microg/ml treatment groups (0.74 +/- 0.03, 0.64 +/- 0.02, 0.52 +/- 0.01 and 0.21 +/- 0.02) than in the control (P < 0.01).

CONCLUSIONTea polyphenols can inhibit the proliferation of human prostate cancer DU145 cells, which may be associated with the decreased expression of the survivin gene.