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目的:探讨Sestrin2在砷化物诱导细胞凋亡反应中的作用及机制。方法:体外培养人肝癌细胞HepG2,以砷化物为刺激源,用免疫印迹和RT-PCR方法检测Sestrin2在砷化物刺激HepG2细胞前后的表达水平差异;用流式细胞术检测敲低Sestrin2前后以及抑制氧化应激反应前后细胞凋亡水平变化情况;用活性氧(ROS)检测试剂盒分析敲低Sestrin2前后细胞在砷化物刺激后的氧化应激水平变化情况。结果:砷化物刺激HepG2细胞后Sestrin2表达水平显著上调;敲低HepG2细胞中Sestrin2表达水平后,细胞凋亡水平明显升高,说明Sestrin2的诱导表达是砷化物诱导细胞凋亡反应中的保护性事件;在敲低Sestrin2表达水平后,砷化物诱导的ROS产生效应和氧化应激反应程度明显加剧;抗氧化剂NAC能够显著逆转Sestrin2对细胞凋亡的保护性效应。结论:Sestrin2在砷化物诱导细胞凋亡反应中可通过抑制ROS产生而发挥拮抗细胞凋亡的保护性作用。
Objective: To investigate the role of Sestrin2 in arsenic-induced apoptosis and its mechanism. Methods: Human hepatocellular carcinoma HepG2 cells were cultured in vitro. The changes of Sestrin2 expression in HepG2 cells stimulated with arsenic were detected by Western blotting and RT-PCR. Flow cytometry was used to detect the expression of Sestrin2 before and after knockdown of Sestrin2 The changes of cell apoptosis were observed before and after oxidative stress. The changes of oxidative stress in arsenic-stimulated cells before and after Sestrin2 knockdown were analyzed by reactive oxygen species (ROS) detection kit. Results: Sestrin2 expression was significantly up-regulated after arsenide-stimulated HepG2 cells; knockdown of Sestrin2 expression in HepG2 cells significantly increased apoptosis, indicating that the induction of Sestrin2 was a protective event in arsenic-induced apoptosis After knocked down the expression of Sestrin2, arsenic-induced ROS production and oxidative stress were significantly increased. Antioxidant NAC significantly reversed the protective effect of Sestrin2 on apoptosis. Conclusion: Sestrin2 can protect cells from apoptosis by inhibiting the production of ROS in arsenic-induced apoptosis.