非小细胞肺癌细胞中OGG1调控顺铂诱导的细胞毒性的作用机制探讨

Mechanism of OGG1 regulation of cisplatin-induced cytotoxicity in non-small cell lung cancer cell

目的:探讨8-氧鸟嘌呤DNA糖基化酶(OGG1)在人肺癌细胞中调控顺铂诱导的细胞毒性的作用机制。方法:采用酶联免疫吸附试验、免疫印迹、流式细胞术和免疫荧光法、线粒体拷贝数和膜电位检测等方法,进行相关实验。结果:顺铂可诱导8-羟基-2'-脱氧鸟苷(8-OHdG)浓度升高,8-OHdG的浓度及细胞凋亡分别与OGG1 mRNA的表达存在显著相关性。外源性表达OGG1促进其DNA修复活性,可降低顺铂诱导的8-OHdG水平,提高非小细胞肺癌(non-small cell lung cancer,NSCLC)细胞活力,并抑制顺铂诱导的NSCLC细胞凋亡,而OGG1沉默则表现相反的结果。此外,过表达OGG1减少顺铂导致的线粒体DNA损伤和功能障碍,沉默OGG1增强顺铂诱导的MAPK/p38通路的激活,导致NSCLC细胞发生凋亡。结论:OGG1的下调有利于提高肺癌细胞对顺铂的敏感性。因此,本研究通过在体外证实OGG1介导的DNA修复在顺铂耐药中的作用,为肺癌的治疗提供了理论支持。

Objective:To investigate the role of 8-oxoguanine DNA glycosylase(OGG1)in cisplatin-cytotoxicity lung cancer cells.Methods:Enzyme-linked immuno sorbent assay(ELISA),Western blotting,flow cytometry,immunofluorescence assay,mitochondrial DNA copy number and mitochondrial membrane potential assays were used to carry out related experiments.Results:Firstly,the result showed cisplatin induced the expression of 8-hydroxy-2'-deoxyguanosine(8-OHdG)by using ELISA analysis and immunofluorescence assays.Correlation analysis confirmed significantly correlation between 8-OHdG,apoptosis and mRNA expression of OGG1.Next,exogenous expression of OGG1 promoted.DNA repair activity to attenuate the level of cisplatin-induced 8-OHdG and increased cell viability after cisplatin-treated in non-small cell lung cancer(NSCLC)cells.Western blotting,TUNEL assays and cell apoptosis analysis were used to confirmed OGG1 protected cisplatin-induced cell apoptosis and OGG1 silencing accelerated cisplatin-induced cell apoptosis in NSCLC cells.Furthermore,mitochondrial DNA copy number and mitochondrial membrane potential assays showed decreasing OGG1 promoted DNA damage and mitochondrial dysfunction after cisplatin treatment.Simultaneously,OGG1 silencing enhanced activation of MAPK/p38 pathways in response to cisplatin and led to NSCLC cell death.Conclusion:Our data showed that down-regulation of OGG1 will be beneficial for the treatment of cisplatin for lung cancer cell.Therefore,this study provides new insight into cancer therapy by demonstrating the role of DNA repair in cisplatin-resistant in vitro.