E3泛素连接酶RNF6促进p27的泛素化降解影响胶质母细胞瘤的增殖和化疗敏感性

胶质母细胞瘤(GBM)是最常见的原发性中枢神经系统肿瘤，其恶性进展快，患者预后差。泛素化的异常调控是促进肿瘤发生的驱动力之一。p27的表达降低或缺失是引起肿瘤恶性进展的重要原由。从p27的泛素化调控角度出发，解析p27蛋白在肿瘤中减少或缺失有着重要的研究意义。前期发现E3泛素连接酶RNF6与p27直接结合并降低p27的蛋白稳定性，且RNF6可增加E3泛素连接酶SKP2的启动子活性。本项目将以探究RNF6促进p27的泛素化降解为目标，阐释RNF6通过泛素化修饰和转录调控途径促进p27泛素化的分子机制。通过体内外泛素化、分子对接、免疫共沉淀和ChIP等方法揭示RNF6直接调控p27泛素化的分子机制，并阐明RNF6转录调控SKP2间接影响p27泛素化的作用机制。本项目的研究进一步完善p27的泛素化调控网络，将为靶向抑制剂的设计和开发奠定理论基础以及为肿瘤的临床诊疗提供新思路和新靶点。

Glioblastoma (GBM) is the most common primary central nervous system (CNS) tumor, which is characterized by fast malignant progression and poor prognosis of patients. Abnormal regulation of ubiquitin is one of the drivers of tumorigenesis. Reduction or loss of p27 expression contributes significantly to malignant progression of tumors. Analysis of the reduction or loss of p27 in tumors from the perspective of the ubiquitination regulation of p27 is of great research significance. According to previous research, the E3 ubiquitin ligase RNF6 can bind with p27 directly and reduce the protein stability of p27; moreover, RNF6 enhances the promoter activity of the E3 ubiquitin ligase SKP2. For the purpose of studying p27 degradation by ubiquitination promoted by RNF6, in this paper, the molecular mechanism of RNF6 promoting p27 ubiquitination by ubiquitination modification and transcriptional regulation is explained. The molecular mechanism behind RNF6’s direct regulation of p27 ubiquitination is also revealed by means of in vitro and in vivo ubiquitination, molecular docking, co-immunoprecipitation, ChIP, etc., and the mechanism of p27 ubiquitination indirectly influenced by RNF6 transcriptional regulation of SKP2 expounded. The research further improves the p27 ubiquitination regulatory network, and may provide a theoretical basis for the design and development of targeted inhibitors as well as new ideas and targets for clinical diagnosis and treatment of tumors.