Experimental Studies On Hydrocycamptothecin-induced Apoptosis In Human Prostate Cancer Cell Ine PC-3

Prostate cancer is common malignant tumor in urinary system. Recently, the morbidity of prostate cancer is rising year by year. By now, there is no effective therapy for androgen-independent prostate cancer. Apoptosis play an important role in tumor occurrence, tumor clearance, tumor conversion, and anti-tumor drugs. HCPT(hydrocycaxnptothecin), which is an inhibitor of nuclear enzyme of topoisomerase I, is an anti-tumor drug extracting from common cainpototheca fruit in China. Some studies have suggest campothecin and its analogues can induce apoptosis of bladder cancer cell, gastric carcinoma cell, liver cancer cell, and prostate cancer cell. Up to now, there is no reports about HCPT inducing apoptosis of PC-3 cell. This experiments study whether HCPT can induce apoptosis of PC-3 cell and explore the mechanism of HCPT.Objective:To study the induction of apoptosis of human prostate cancer cell line PC-3 treated with hydroxycampotothecin.Methods:We analysed the hydrocampotothecin inhabitation to PC-3 cell growth by MiT assay, observed morphlogical aspects of apoptosis by Inverted Biological microscope and fluoroscent microscope and electron microscope, assessed apoptosis rate by flow cytometric method, and identified the DNA break by agarose gel electronphoresis.Result:At dose of lO~, iO~, ~ iO~, 102, 10~ mglml, hydroxycamptothecin significantly inhibited growth of PC-3 cell, the inhibition of HCPT to the growth of PC-3 cell was dose-dependent and time- dependent, The 1C50 of hydroxycamptothecin for 12h, 24h, 48h was 6.42 X i&, 1.37 X I &, 2.92 X 1 O~mg/ml respectively. The morphological change includedIIIcondensed chromatin, nuclear fragmentation and apoptotic body. Agarose gel electronphoresis of DNA revealed ladder pattern. FCM not only show apoptotic peak, but also can estimate the rate of apoptosis. Our FCM data suggested that hydroxycaptothecin mainly affect the S phase in PC-3 cell cycle.Conclusion:Hydroxycaptothecin can inhibit the growth of PC-3 cell, and can induce apoptosis of PC-3 cell in vitro, and mainly affect the S phase in PC-3 cell cycle. Induction of apoptosis is one mechnism of hydroxycaptothecin抯 anti-tumor effection. We may use HCPT in clinical trials.