抑制OGG1增加替莫唑胺对神经胶质瘤细胞U251的敏感性及机制探讨

Inhibition of OGG1 Increases Temozolomide Sensitivity to Glioma Cells U251 and Its Mechanism

目的探讨8-羟基鸟嘌呤DNA糖苷酶(OGG1)对脑神经胶质瘤细胞增殖及替莫唑胺(temozolomide,TMZ)化疗敏感性的影响。方法采用光镜、CCK-8、活性氧(ROS)检测试剂盒DCFH-DA探针、Western blot观察及检测替莫唑胺处理后神经胶质瘤细胞的形态、细胞活力、细胞内活性氧水平及OGG1蛋白的表达水平;Real time-PCR技术检测OGG1 mRNA干扰率;OGG1下调后,U251的细胞存活率及OGG1蛋白的表达水平。结果与对照组相比,替莫唑胺处理后,U251细胞的生存能力显著下降(P<0.05),ROS水平显著增加(P<0.05),OGG1蛋白表达水平显著降低(P<0.05),当替莫唑胺剂量为100μmol/L时,对U251细胞的损伤最大(P<0.01)。当OGG1 siRNA干扰U251细胞OGG1后,OGG1 mRNA及OGG1蛋白的表达水平降低(P<0.05),而利用低剂量的替莫唑胺对U251细胞处理时,细胞存活率显著降低(P<0.05)。结论OGG1通过ROS通路,介导替莫唑胺对神经胶质瘤细胞U251的氧化损伤,OGG1抑制可增强神经胶质瘤细胞对TMZ的化疗敏感性。

Objective To investigate the effect of 8-oxyguanine DNA glycosylase(OGG1)on the proliferation of brain glioma cells and the chemosensitivity of temozolomide(TMZ).Methods Light microscope,CCK-8,reactive oxygen species(ROS)detection kit DCFH-DA probe and western blot were used to observe and detect the morphology,cell viability,intracellular reactive oxygen species and OGG1 protein of glioma cells treated with TMZ.Real time-PCR technology was used to detect OGG1 mRNA interference rate.After down-regulation of OGG1,U251 cell survival rate and OGG1 protein expression were observed.Results Compared with control group,after temozolomide treatment,U251 cells was significantly decreased(P<0.05),ROS were significantly increased(P<0.05),and OGG1 protein expression levels were significantly reduced(P<0.05).When TMZ dose was 100μmol/L,the damage to U251 cells was the greatest(P<0.01).When OGG1 siRNA interfered with OGG1 in U251 cells,expressions of OGG1 mRNA and OGG1 protein decreased(P<0.05).However,when U251 cells were treated with low-dose TMZ,cell survival rate was significantly reduced(P<0.05).Conclusion OGG1 could mediate oxidative damage caused by TMZ to U251 glioma cells through ROS pathway.Inhibition by OGG1 could enhance chemotherapy sensitivity of glioma cells to TMZ.