RNF146调控DNA损伤修复蛋白Ku86在脑胶质瘤放疗抵抗中的作用研究

Radiotherapy is an important part of cerebral glial comprehensive treatment. However, radiotherapy resistance has a serious effect on the curative effect of glioma. DNA damage and repair is an important factor affecting radiotherapy sensitivity. We found that E3 ubiquitin ligase RNF146 can increase the radiotherapy sensitivity of glioma cells. TCGA database retrieval and immunohistochemical detection of combined glioma tissues showed that RNF146 was closely related to the pathological stage, classification and clinical prognosis of glioma. In U251 glioma cells in proteomics system analysis, we found that DNA repair protein Ku86 is negatively regulated by the RNF146 in non-homologous end joining after double-stranded DNA breakage.This topic proposed on the basis of previous work, in order to explore KU86 RNF146 regulation as the main line, integrated use of bioinformatics retrieval, organization chip, proteomics, RNAi technology, such as mice, molecular cloning, and a tumor-burdened RNF146 control system research KU86 ubiquitin chemical degradation of glioma after radiotherapy, the effects of DNA damage repair, help to elucidate the molecular mechanism of glioma radiation resistance, for improving glioma radiation sensitive molecular targets to provide experimental basis.

放疗是脑胶质综合治疗的重要组成部分，然而放疗抵抗却严重影响了脑胶质瘤的疗效。DNA损伤修复是影响放疗敏感性的重要因素。我们发现E3泛素连接酶RNF146能够增加脑胶质瘤细胞的放疗敏感性。TCGA数据库检索联合胶质瘤组织芯片免疫组化检测显示RNF146与脑胶质瘤的病理分期、分级以及临床预后密切相关。在胶质瘤细胞U251的蛋白组学系统分析中我们发现参与DNA双链断裂后非同源末端连接修复的DNA损伤修复蛋白Ku86是在蛋白水平受RNF146负性调控的下游分子。本课题拟在前期工作基础上，以探索RNF146调控Ku86为主线，综合运用生物信息学检索、组织芯片、蛋白组学、RNAi、分子克隆和荷瘤小鼠等技术，系统研究RNF146调控Ku86泛素化降解对胶质瘤放疗后DNA损伤修复能力的影响，为阐明胶质瘤放疗抵抗的分子机制，寻找提高胶质瘤放疗敏感性的分子靶点提供理论和实验依据。

DNA损伤修复能力增强常常是肿瘤细胞放疗抵抗的重要原因。我们发现了一种特异性表达于中枢神经系统的具有E3泛素连接酶活性的DNA损伤修复蛋白——锌指蛋白146（RNF146）。生理状态下的RNF146特异性表达于神经元，星形胶质细胞几乎不表达。我们发现在胶质瘤组织中RNF146显著上调，且其表达水平与脑胶质瘤的病理分级、临床预后负相关。体外培养的脑胶质瘤细胞中敲减RNF146后，放疗敏感性显著降低。RNF146敲减的脑胶质瘤荷瘤小鼠的肿瘤组织表现出更强的增殖活力。深入研究发现RNF146通过促进非同源末端连接修复复合体的Ku86亚基发生泛素化降解在蛋白水平负性调节Ku86表达，是其促进胶质瘤放疗抵抗的重要原因。上述工作发表北大核心文章4篇，科技源核心文章1篇，培养硕士研究生2名，1篇SCI文章处于under review阶段，申请专利1项。