姜黄素对胃癌细胞株凋亡抑制蛋白家族及Smac基因表达的影响

Effects of Curcumin on IAPs and Smac Gene Expression of Gastric Cancer Cell Line

目的观察姜黄素(curcumin)对人胃癌细胞株凋亡抑制蛋白(IAP)家族和Smac基因表达的影响,探讨姜黄素诱导胃癌细胞凋亡的分子机制. 方法 10～40 μmol/L 姜黄素分别处理胃癌细胞株MKN-45 6～24 h后,MTT比色法检测癌细胞生长活性,末端TdT酶标记技术和DNA Ladder检测细胞凋亡;逆转录聚合酶链反应(RT-PCR)和Western blot法检测IAP家族(Survivin、XIAP)和Smac基因表达;比色法检测癌细胞Caspase-3活性改变. 结果同对照组比较,不同浓度姜黄素作用后癌细胞生长明显减慢,抑制率为12.18%～68.15%(P<0.01),部分细胞呈现典型凋亡形态学改变,凝胶电泳可见'梯形'条带,凋亡率为9.24%～28.12%(P<0.01);Survivin、XIAP基因mRNA和蛋白水平显著下调(均P<0.01),而Smac基因表达增强(P<0.01),癌细胞Caspase-3活性增强2.27 ～6.67倍(P<0.01). 结论姜黄素可显著诱导胃癌MKN-45细胞凋亡,通过上调Smac、下调Survivin和XIAP基因表达,进而活化Caspase-3是其作用机制之一.

Objective To explore the effects of curcumin on inhibitor of apoptosis proteins (IAPs) and Smac gene expression in gastric cancer cell line,in order to study the molecular mechanisms of gastric cancer cell apoptosis induced by curcumin.Methods After being treated with 10-40 μmol/L curcumin for 6-24 h,growth activities of MKN-45 cells were detected by tetrazolium bromide (MTT) colorimetry. Cell apoptosis was assayed by in situ terminally labeled transferase technique (TUNEL) and DNA ladder methods. IAPs (Survivin,XIAP) and Smac gene expression was detected by RT-PCR and Western blot. Cellular Caspase-3 activity levels were detected by colorimetry method.Results When compared with control group,cell growth could be significantly inhibited by various concentrations of curcumin,with inhibitory ratios being 12.18 %-68.15 % (P<0.01). Partial MKN-45 cells presented characteristic morphological changes of apoptosis,with trapezia bands on gel electrophoresis. The apoptosis rate was 9.24 %-28.12 % (P<0.01). The mRNA and protein levels of Survivin and XIAP were significantly down-regulated (P<0.01),while those of Smac up-regulated (P<0.01). The Caspase-3 activities of tumor cells were increased by 2.27-6.67 times (P<0.01).Conclusion Curcumin could significantly induce apoptosis of gastric cancer cell line MKN-45. One of its mechanisms was through up-regulating Smac and down-regulating Survivin and XIAP expression,leading to activation of Caspase-3.