【摘要】 目的:探讨夜香树3种甾体皂苷(SSCN)对肝癌细胞株BEL-7404增殖抑制作用及其机制。方法:夜香树叶用有机溶剂提取并鉴定3种SSCN,体外培养BEL-7404细胞,采用细胞集落形成法体外测定SSCN对人肝癌细胞株BEL-7404增殖的影响;流式细胞技术检测细胞周期与凋亡率变化;单细胞凝胶电泳(SCGE)分析细胞DNA损伤;用质粒PBR322解旋反应观察SSCN对肿瘤BEL-7404细胞拓扑异构酶Ⅱ的影响。结果:3种SSCN对肝癌细胞BEL7404有明显的抑制作用,并呈剂量-时间依赖性,流式细胞仪分析结果显示,G0/G1和G2/M期细胞数增多,S期减少,呈现细胞阻滞现象,并伴有大量的细胞凋亡。SSCN可以引起DNA损伤,对TopoⅡ活性有抑制作用,可抑制TopoⅡ介导的质粒DNA超螺旋的解旋。结论:SSCN对BEL-7404细胞具有增殖抑制和诱导凋亡作用,其机制可能是:①阻滞细胞于G2/M期,最终导致细胞死亡。②损伤DNA,造成DNA双链断裂。③抑制Topo II的催化活性,使DNA超螺旋增加。更多还原

【Abstract】 Objective:To investigate the effect of three kind of steroid saponins,extract obtained from Cestrum nocturnum on the human hepatocellular carcinoma BEL-7404 cell proliferation and its mechanism in vitro.Method: Three kind of steroid saponins of the leaves of C.nocturnum(SSCN) were separated and identified their structures by solvent.The BEL-7404 cells were cultured in vitro and cell colony measurement technique assay was used to determine the inhibition of cell proliferation.Alteration of cell cycle and apoptosis rate was defected by flow cytometry(FCM).The single cell microgel electrophoresis technique was used to analyse effect of DNA damage of BEL-7404.The effects of SSCN on Topo II mediated-pBR322 DNA unwinding were measured by using agarose gel electrophoresis.Result: SSCN significantly inhibited the proliferation of BEL-7404 cells in a time and dose-dependent manner.The results from FCM assay indicated that the percentage of cells in S phase decreased,while the percentage of cells in G0/G1 and G2/M phases increased,the phenomenon of blockage appeared and cell death was induced.The bioactive components of SSCN have effect on DNA damaged and inhibited the Topo II mediated relaxation of supercoiled pBR322 DNA effectively.Conclusion: SSCN could effectively inhibit cell proliferation and induce BEL-7404 apoptosis.With a direct relation to the dose and time,which may be correlated with factors as follows:①SSCN can arrest the cell cycle at G0/G1 and G2/M phase;②DNA damage and cleavage of SSCN on DNA double strands may be a potential mechanism.③CNSN can inhibit the catalytic activity of Topo II.更多还原