熊果酸对人宫颈癌SiHa细胞增殖和凋亡的影响及其机制

目的探讨熊果酸（UA）对人宫颈癌SiHa细胞增殖和凋亡的影响及其分子机制。方法采用MTT法观察UA对SiHa细胞增殖的影响,流式细胞术检测UA对细胞周期和凋亡率的影响,Hoechst33258荧光染色和透射电镜观察凋亡细胞的形态变化,RT-PCR技术检测SiHa细胞中转化生长因子（TGF）-β1mRNA和Smad 4 mRNA表达的变化。结果 UA可明显抑制SiHa细胞生长,并呈时间和浓度依赖趋势（P〈0.05或0.01）;流式细胞术检测发现,UA作用24 h、48 h和72 h后SiHa细胞周期阻滞在G0/G1期,并检测到凋亡峰,凋亡率分别为1.16%、16.37%、18.70%（P〈0.05或0.01）;Hoechst33258荧光染色观察可见胞核染色质不均,呈颗粒状或块状荧光,透射电镜观察出现胞质浓缩、胞核染色质凝聚、边集等典型凋亡细胞核形态变化;RT-PCR检测到TGF-β1mRNA表达减弱,并呈时间依赖趋势,Smad 4 mRNA表达随时间延长而增强。结论熊果酸在体外对SiHa细胞具有抗增殖和诱导凋亡作用,其机制可能与TGF-β/Smads信号传导通路有关;UA可能通过上调Smad 4的表达恢复TGF-β/Smads信号传导通路,从而诱导细胞凋亡。

The Proliferation and Apoptosis Effects and Mechanisms Induced by Ursolic Acid in Human Cervical Carcinoma SiHa Cells

Objective To investigate the inhibitory and apoptosis effects and possible mechanisms of ursolic acid（UA） on the proliferation of human cervical carcinoma SiHa cells.Methods The effect of UA on the proliferation of SiHa cells was measured by MTT method.Cell cycle and apoptosis rates were observed by flow cytometry,Hoechst 33258 fluorescent dying and electron microscope were used to observe UA induced morphological changes.The gene expression of TGF-β1,Smad 4 involved in the effects of UA on SiHa cells were studied by RT-PCR.Results UA strongly inhibited the growth of SiHa cells in a dose-and time-dependent manner.Cell cycle analysis revealed that SiHa cells treated by UA for 24h,48h and 72h were blocked predominantly in G0/G1 phase（P0.05）,apoptotic peak was found with flow cytometry,and the apoptosis rates were 1.16%,16.37%,and 18.70% respectively.The morphological changes of apoptosis,such as cytoplasm and nuclear condensation were observed by Hoechst 33258 fluorescent dying and electron microscope in UA treated cells.RT-PCR analysis revealed that the expression of TGF-β1mRNA decreased in a time-dependent manner and Smad 4 mRNA increased in a time-dependent manner in UA-treated cells.Conclusion UA has the effects of inhibition to SiHa cells proliferation and induction of cell apoptosis.The mechanisms may be related to the TGF-β/Smads signaling pathway.UA can up-regulated activity Smad 4 mRNA and recoved the TGF-β/Smads signaling pathway,which is related to an increased cell apoptosis.