番荔枝内酯单体squamocin诱导人肺腺癌A549细胞凋亡的实验研究

目的 观察番荔枝内酯单体squamocin对人肺腺癌A549细胞的体外增殖抑制及诱导凋亡的作用，并探讨squamocin诱导肿瘤细胞凋亡的机制。方法 MTT法检测不同浓度的squamocin对人肺腺癌A549细胞体外增殖的影响；流式细胞仪检测squamocin干预在不同时间点对人肺腺癌A549细胞凋亡率的影响；Western blotting检测squamocin干预前后细胞凋亡相关蛋白caspase-3、Bax和Bcl-2的表达情况。结果 MTT法显示，squamocin对人肺腺癌A549细胞的体外抑制作用随着squamocin浓度的增加和作用时间的延长而增强，24、48、72h半数抑制浓度（IC50）分别为16.54、9.28、6.17μg／ml；流式细胞仪检测显示，在24、48、72h实验组人肺腺癌A549细胞凋亡率之间及其与阴性对照组比较，差异均有统计学意义（P＜0.01），其中实验组72h的细胞凋亡率最高，为（51.87±1.79）％Western blotting显示，squamocin干预后细胞凋亡相关蛋白caspase-3和Bax表达上调，Bcl-2表达明显下调。结论 squamocin可诱导人肺腺癌A549细胞凋亡，这可能与squamocin上调细胞凋亡相关蛋白caspase-3、Bax表达以及降低抑制细胞凋亡基因Bcl-2表达有关。

Apoptosis-inducing effect of squamocin on lung adenocarcinoma cell line A549

Objective To investigate the effect of squamocin on proliferation and apoptosis of A549 cells,and to probe into its possible mechanism.Methods MTT assay was used to examine the proliferation inhibition of squamocin on A549 cells,the apoptosis rate of A549 cells treated by squamocin was detected by flow cytometry,and Western blotting was used to detect the change of the apoptosis-related proteins caspase-3,Bax and Bcl-2 on A549 cells.Results The inhibition effect of squamocin on A549 cells was in dose-time dependent manner.The IC50of 24,48 and 72h were 16.54,9.28 and 6.17μg/ml.The apoptosis rate of A549 cells obviously raised after the treatment of squamocin,and the highest apoptosis rate of squamocin group was（51.87±1.79）% at 72h.Western blotting showed that the expression of caspase-3 and Bax increased,while Bcl-2 decreased.Conclusion Squamocin has apoptosis-inducing effect on A549 cells.The mechanism may be associated with up-regulation of caspase-3 and Bax,and down-regulation of Bcl-2 by squamocin.