OBJECTIVETo study the effect of Triptolide (TL) on the growth of prostate carcinoma cell line, and analyze its function and mechanism in anti-prostate cancer.

METHODSMTT experiments were performed to examine the inhibiting effect of TL on the proliferation of RM-1 cells, cell morphological changes observed by acridine staining, cellular cycles and apoptosis peak analyzed by flow cytometry, the apoptosis fracture zone investigated with DNA electrophoresis, and the expressions of caspase-3 and bcl-2 mRNA in RM-1 cells examined by RT-PCR.

RESULTSThe results of MTT experiments showed that after the treatment of TL (5, 10, 20, 40 and 80 ng/ml), the RM-1 cell proliferation inhibition rates were 9.8%, 25.1%, 39.2%, 48.8% and 53.2% respectively; 12, 24, 36 and 48 hours after the treatment of TL (10 and 20 ng/ml), the cell proliferation inhibition rates were 8.4%, 25.1%, 36.1%, 42.4% and 10.2%, 39.2%, 50.2% and 58.5% respectively. Acridine staining after the TL treatment revealed nucleus condensation, cell membrane invagination, irregular orange particles in the cells and apoptosis morphological changes; flow cytometry tests showed that 48 hours after the TL treatment (10, 20 ng/ml) of RM-1 cells, an obvious apoptosis peak appeared before the G1 stage; 24, 36 and 48 hours after it, DNA "trapezoid" strips could be seen; the caspase-3 mRNA expression in the TL treated cells was higher, and the bcl-2 mRNA expression was lower than in the controls.

CONCLUSIONTL can decrease bcl-2 expression, increase caspase-3 expression, induce apoptosis of prostate carcinoma cells, and consequently inhibit the proliferation of RM-1 cells in mice.