低氧条件下SIRT3调控ROS介导的氧化应激反应对肺癌细胞凋亡的影响

The effect of SIRT3 on lung cancer cell apoptosis by regulating ROS-mediated oxidative stress under hypoxic conditions

目的探讨低氧条件下去乙酰化酶3(SIRT3)通过活性氧(ROS)对肺癌细胞氧化应激反应和低氧诱导因子1α(HIF-1α)表达的影响及其机制。方法将人非小细胞肺癌A549细胞暴露于低氧条件下培养0、12、24、48 h;RT-PCR和Western blot检测细胞中HIF-1α和SIRT3 mRNA和蛋白的表达,确定最佳低氧诱导时间。将A549细胞分成5组:对照组、低氧组、低氧+ROS抑制剂N-乙酰半胱胺酸(NAC)组、低氧+SIRT3过表达(SIRT3-OE)组和低氧+SIRT3-OE+NAC组;MTT法检测细胞增殖情况;流式细胞术检测细胞凋亡情况;RT-PCR和Western blot法检测各组细胞中HIF-1α和SIRT3 mRNA和蛋白的表达;流式细胞术检测各组细胞中ROS含量;生化试剂盒检测各组细胞中丙二醛(MDA)、超氧化物歧化酶(SOD)和谷胱甘肽(GSH)的含量。结果最佳低氧诱导时间为24 h。与对照组相比,低氧组细胞凋亡率、细胞中SIRT3 mRNA和蛋白水平、SOD和GSH含量均降低(P<0.01),细胞增殖能力、细胞中HIF-1αmRNA和蛋白水平、ROS和MDA含量均升高(P<0.01);与低氧组相比,低氧+NAC组和低氧+SIRT3-OE组细胞凋亡率、细胞中SIRT3 mRNA和蛋白水平、SOD和GSH含量均升高(P<0.05),细胞增殖能力、细胞中HIF-1αmRNA和蛋白水平、ROS和MDA含量均降低(P<0.05);与低氧+NAC组相比,低氧+SIRT3-OE+NAC组细胞凋亡率、细胞中SIRT3 mRNA和蛋白水平、SOD和GSH含量均升高(P<0.01),细胞增殖能力、细胞中HIF-1αmRNA和蛋白水平、ROS和MDA含量均降低(P<0.01)。结论低氧条件下SIRT3能够通过介导ROS抑制肺癌细胞中的氧化应激反应和HIF-1α的表达来促进细胞凋亡,抑制肺癌进展。

Objective To investigate the effect of sirtuin 3(SIRT3)on the oxidative stress response and hypoxia inducible factor-1α(HIF-1α)expression in lung cancer cells through reactive oxygen species(ROS)under hypoxic conditions and its mechanism.Methods Human non-small cell lung cancer A549 cells were exposed to hypoxia for 0 h,12 h,24 h and 48 h.The mRNA and protein expressions of HIF-1αand SIRT3 were detected by RT-PCR and Western blot to determine the optimal time of hypoxia induction.A549 cells were divided into 5 groups:control group,hypoxia group,hypoxia+ROS inhibitor n-acetylcysteine(NAC)group,hypoxia+(SIRT3 overexpression)SIRT3-OE group and hypoxia+SIRT3-OE+NAC group.Cell proliferation was detected by MTT assay.Cell apoptosis was detected by flow cytometry.The mRNA and protein expressions of HIF-1αand SIRT3 in each group were detected by RT-PCR and Western blot.ROS content in each group was detected by flow cytometry.The contents of malondialdehyde(MDA),superoxide dismutase(SOD)and glutathione(GSH)in the cells of each group were detected by biochemical kits.Results The optimal induction time of hypoxia was 24 h.Compared with the control group,the apoptosis rate,SIRT3 mRNA and protein levels,SOD and GSH contents in the hypoxia group significantly decreased(P<0.01),the cell proliferation ability,HIF-1αmRNA and protein levels,ROS and MDA content in cells significantly increased(P<0.01).Compared with the hypoxia group,the apoptosis rate,SIRT3 mRNA and protein levels,SOD and GSH contents in the hypoxia+NAC and hypoxia+SIRT3-OE groups increased(P<0.05),the cell proliferation ability,HIF-1αmRNA and protein levels,ROS and MDA content in cells decreased(P<0.05).Compared with the hypoxia+NAC group,the apoptosis rate,SIRT3 mRNA and protein levels,SOD and GSH contents in the hypoxia+SIRT3-OE+NAC group significantly increased(P<0.01),the cell proliferation ability,HIF-1αmRNA and protein levels,ROS and MDA content in cells significantly decreased(P<0.01).Conclusion Under hypoxic conditions,SIRT3 can promote cell apoptosis and inhibit lung cancer progression by mediating ROS to inhibit oxidative stress response and HIF-1αexpression in lung cancer cells.