Objective To investigate the effect of Smac mimetics LCL161 on the proliferation and apoptosis of non-small cell lung cancer A549 cells and its mechanism.Methods A549 cells with logarithmic growth phase were divided into control group(0.1% dimethyl sulfoxide),5 mmol/L LCL161 group,10 mmol/L LCL161 group and 20 mmol/L LCL161 group.After 24,48 and 72 hours of intervention with corresponding drugs,methyl thiazolyl tetrazolium assay was used to detect the cell proliferation of each group.After 48 hours of intervention, Hoechst staining was used to detect the cell apoptosis of each group.The cells were collected from the control group,the 5 mmol/L LCL161 group and the 10 mmol/L LCL161 group after 48 hours of intervention,then Western Blot was used to measure the expression levels of X-linked inhibitor of apoptosis protein(XIAP),B-cell lymphoma-2-associated X protein(Bax) and cysteinyl aspartate specific proteinase(Caspase) proteins.Results A490values of A549 cells decreased at all time points in the order of the control group,the 5 mmol/L LCL161 group,the 10 mmol/L LCL161 group and the 20 mmol/L LCL161 group(all P<0.05).A490values of A549 cells in the 5 mmol/L LCL161 group and 20 mmol/L LCL161 group decreased over time(all P<0.05),and A490value of A549 cells at 72 hours was higher than the value at 24 or 48 hours in the 10 mmol/L LCL161 group(all P<0.05).The number of apoptotic A549 cells increased in the order of the control group, the 5 mmol/L LCL161 group,the 10 mmol/L LCL161 group and the 20 mmol/L LCL161 group(all P<0.05).The expression level of XIAP protein decreased but of Bax protein or Caspase-3 protein increased in the order of the control group,the 5 mmol/L LCL161 group and the 10 mmol/L LCL161 group(all P<0.05).Conclusion LCL161 can inhibit the proliferation and induce the apoptosis of lung cancer A549 cells,whose mechanism may correlate with down-regulating XIAP protein and up-regulating Bax protein and Caspase-3 protein.%目的 探讨Smac类似物LCL161对非小细胞肺癌A549细胞增殖及凋亡的影响及其机制.方法 将处于对数生长期的A549细胞分为对照组(0.1%二甲基亚砜)及5、10、20 mmol/L LCL161组,分别采用相应药物干预24 h、48 h、72 h后,用四甲基偶氮唑盐法检测各组细胞的增殖情况,药物干预48 h后用Hoechst荧光染色法计数凋亡细胞.取对照组及5、10 mmol/L LCL161组培养48 h后的细胞,用免疫印迹法检测X连锁凋亡抑制蛋白(XIAP)、B淋巴细胞瘤-2相关X蛋白(Bax)和含半胱氨酸的天冬氨酸蛋白水解酶(Caspase)的蛋白表达情况.结果 各时点,对照组、5 mmol/L LCL161组、10 mmol/L LCL161组、20 mmol/L LCL161组 A549细胞 A490值依次降低(均 P <0.05);5 mmol/L LCL161组、20 mmol/L LCL161组A549细胞A490值随时间延长而降低(均P<0.05),10 mmol/L LCL161组A549细胞72 h A490值均低于24 h、48 h (均P<0.05).对照组、5 mmol/L LCL161组、10 mmol/L LCL161组、20 mmol/L LCL161组 A549细胞凋亡数依次增高(均P<0.05).对照组、5 mmol/L LCL161组、10 mmol/L LCL161组XIAP蛋白表达水平依次降低,而Bax和Caspase-3蛋白表达水平依次升高(均P<0.05).结论 LCL161对肺癌A549细胞具有增殖抑制及凋亡诱导作用,其机制可能与下调XIAP、上调Bax和Caspase-3相关.
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