OBJECTIVETo observe the effects of hydroxycamptothecin (HCPT) on the apoptosis of prostate cancer cell line PC-3 and to explore the possible mechanism.

METHODSThe influence of different concentrations (1 x 10(-1), 1 x 10(-2), 1 x 10(-3), 1 x 10(-4) mg/ml) of HCPT on PC-3 cell proliferation at different time (12, 24, 48 h) was determined by tetrazolium (MTT) assay. The morphologic changes of the apoptotic cells were observed by acridine orange/ethidium bromide dyeing. The DNA of the apoptotic cells was analyzed with agarose gel electrophoresis. The apoptosis rate of HCPT on prostate cancer cells was analyzed by flow cytometry (FCM).

RESULTSThe growth of PC-3 was inhibited by HCPT in a time- and dose- dependent manner. The values of IC50 were 6.50 x 10(-2) mg/ ml (12 h), 2.35 x 10(-2) mg/ml (24 h) and 5.31 x 10(-3) mg/ml (48 h) respectively. The typical apoptotic cells under the fluorescence microscope showed budding phenomena and apoptotic bodies. And the DNA ladder was observed in ultraviolet light. FCM analysis showed that the apoptosis rate of PC-3 cells increased with the increasing dose of HCPT, which reached the peak (35.76%) at 1 x 10(-3) mg/ml.

CONCLUSIONHCPT could suppress PC-3 cell proliferation significantly by inducing the apoptosis of PC-3 cells. However, the mechanism is yet to be further studied.