Objective To examine the sensitivity of HepG2 cells to single-walled carbon nanohoms (SWNHs) at different SIRT1 expression levels.Methods HepG2 cells were transfected with si-SIRT1 and pLV-SIRT1 to obtain the overexpressing and knockdown SIRT1 cell lines,respectively.The effects of different SIRT1 expression levels on the cell cycle of HepG2 cells were detected with flow cytometry.HepG2 cells were treated with different concentrations of SWNHs,and the sensitivity of HepG2 cells to SWNHs was evaluated with CCK-8 method.Western blotting was used to investigate the effects of SIRT1 on the apoptosis of HepG2 cells.Results Knockdown si-SIRT1-HepG2 and overexpressing pLV-SIRT1-HepG2 cell lines were obtained.Cell cycle arrest was observed in si-SIRT1 group,and the apoptotic cells rate were (14.94± 1.22)％ compared to (5.43±0.34)％ in HepG2 group and (4.49±0.34)％ in pLV-SIRT1 group,with statistical significance (P＜ 0.05).SIRT1 knockdown enhances the sensitivity of HepG2 cells to SWNHs.The cell viability of si-SIRT1-HepG2 cells decreased to (43.22±2.21)％ after being treated with the low concentration of SWNHsl0 for 24 h,and decreased to (2.02± 0.13)％ after being treated with the maximum dose SWNHs40 for 48 h,with significant differences compared with the control group (HepG2 group) (P＜0.05).The western-blot verified that the expression of P53 in si-SIRT1 group was increased,and the expressions of Caspase-3 and Caspase-7 in the downstream related apoptosis protein were also at the high levels.Conclusion By knocking down SIRT1,HepG2 cell cycle arrest can be observed and the sensitivity of HepG2 cell to SWNHs is significantly enhanced.SWNHs is expected to be a new effective method for the biological treatment of liver cancer.%目的:探讨SIRT1基因敲低增强HepG2细胞对单壁碳纳米角(Single-Walled Carbon Nanohorns,SWNHs)的敏感性.方法:通过在HepG2细胞中建立过表达和敲低SIRT1的细胞株,流式细胞检测不同SIRT1表达水平对HepG2细胞周期的影响;采用不同浓度SWNHs对HepG2细胞进行处理,CCK-8法评估HepG2细胞对SWNHs的敏感性;采用Westernblotting探索SIRT1影响HepG2细胞凋亡的机制.结果:获得低表达si-SIRT1和高表达pLV-SIRT1细胞株,发现si-SIRT1组细胞周期阻滞,并且有(14.94±1.22)％细胞出现凋亡,HepG2组和pLV-SIRT1组细胞凋亡率分别为(5.43±0.34)％和(4.49+0.34)％,si-SIRT1组与之相比,差异具有统计学意义(P＜0.05);SIRT1基因敲低增强HepG2细胞对SWNHs的敏感性,低表达si-SIRT1组的数据显示,低浓度SWNHsl0在24h后si-SIRT l-HepG2细胞的活性下降到(43.22±2.21)％,而最大剂量SWNHs40在48 h后si-SIRTl-HepG2细胞的活性下降到(2.02±0.13)％,与对照组(HepG2组)相比差异具有统计学意义(P＜0.05);通过Western-blotting验证,si-SIRT1组的P53表达增高,其相关下游凋亡蛋白Caspase-3、Caspase-7也出现高表达.结论:通过敲低SIRT1后HepG2细胞周期阻滞,对SWNHs的敏感性显著增强,SWNHs有望成为一种有效的生物治疗肝癌的新方法.
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