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目的初步探讨核转录因子NF-κB在TRAIL诱导肝癌细胞发生凋亡过程中的作用和可能机制。方法应用流式细胞仪技术检测经TRAIL和(或)MG-132处理后,肝癌细胞SMMC-7721凋亡发生情况;采用蛋白印渍技术检测TRAIL处理后SMMC-7721细胞凋亡相关蛋白表达情况;并用ELISA法检测NF-κB活性变化。结果单独使用TRAIL后,肝癌细胞发生凋亡,其凋亡指数为15．1％;若联合应用NF-κB抑制剂-MG-132后,则凋亡指数达27．4％,明显高于前者(P<0．01);同时,两者均高于对照组(P<0．01)。SMMC-7721细胞经TRAIL处理后,抗凋亡蛋白表达增加,而促凋亡蛋白表达下降。另外,经TRAIL单独处理后,细胞的NF-κB活性(0．49±0．02)明显高于其余各组(P<0．01)。结论NF-κB在TRAIL诱导的肝癌细胞凋亡过程中被激活,而NF-κB又可能通过促进抗凋亡蛋白的表达、抑制促凋亡蛋白的表达,从而抑制肿瘤细胞的凋亡。
Objective To investigate the role and possible mechanism of nuclear factor NF-κB in the apoptosis of hepatoma cells induced by TRAIL. Methods Flow cytometry was used to detect the apoptosis of SMMC-7721 cells treated with TRAIL and (or) MG-132. The expression of apoptosis-related proteins in SMMC-7721 cells was detected by protein-printing technique. The activity of NF-κB was detected by ELISA. Results After TRAIL alone, apoptosis of hepatocellular carcinoma cells was observed with an apoptotic index of 15.1%. If NF-κB inhibitor MG-132 was used in combination, the apoptotic index was 27.4%, which was significantly higher than that of the former. (P<0.01); at the same time, both were higher than the control group (P<0.01). After SMMC-7721 cells were treated with TRAIL, the expression of anti-apoptotic protein increased and the expression of pro-apoptotic protein decreased. In addition, the activity of NF-κB (0.49±0.02) was significantly higher in the cells treated with TRAIL than in the other groups (P<0.01). Conclusion NF-κB is activated during TRAIL-induced apoptosis of hepatoma cells, and NF-κB may inhibit the apoptosis of tumor cells by promoting the expression of anti-apoptotic proteins and inhibiting the expression of pro-apoptotic proteins.