ATRX调控组蛋白甲基转移酶重分布介导脑胶质瘤耐药性的机制研究

DNA损伤修复是影响脑胶质瘤患者化疗敏感性的重要因素。申请人前期利用表达谱芯片、甲基化芯片、高通量染色质沉淀测序等技术发现：耐药脑胶质瘤中异常高表达的ATRX通过招募甲基转移酶调节组蛋白甲基化，抑制FADD表达，进而促进PARP1稳定，调节替莫唑胺化疗敏感性。在此基础上，申请人拟利用染色质免疫共沉淀等技术探究ATRX表达异常升高的分子机制；通过生物学实验验证敲除ATRX对耐药胶质瘤细胞替莫唑胺敏感性以及PARP1蛋白稳定性的影响；运用高通量免疫共沉淀测序技术探究ATRX通过调节蛋白质甲基转移酶EZH2的重分布介导FADD启动子区组蛋白H3K27三甲基化抑制其表达并促进PARP1稳定的机制。本研究可揭示耐药脑胶质瘤中ATRX异常表达并促进PARP1稳定性介导脑胶质瘤替莫唑胺治疗抵抗的分子机制，为脑胶质瘤精准治疗提供新的理论依据。

Chemo resistance of temozolomide (TMZ), the first-line chemotherapeutic agent, is a major issue in the management of patients with glioma. Alterations of ATRX constitute one of the most prevalent genetic abnormalities in gliomas. Previously, we applied the mRNA array, methylation array, and ChIP-seq to find that higher level of ATRX was detected in TMZ resistant glioma cells compared with the parental cells. ATRX could recruit EZH2, a methyltransferase, to promote tri-methylation of H3K27 in FADD promoter region, which resulted in the suppressed expression of FADD. Based on the results, we aim to explore the molecular mechanism of TMZ resistance by upregulated ATRX regulating PARP1 stabilization in TMZ resistant glioma cells. We will reveal the biological mechanism that overexpression of ATRX in TMZ resistance glioma cells by applying chromatin immunoprecipitation assay, and explore whether knocking out ATRX could influence TMZ sensitivity and PARP1 stabilization in TMZ resistance glioma cells and ATRX stabilizes PARP1 by suppressing FADD expression. ChIP-seq and immunoprecipitation assay helps to explore ATRX facilitating tri-methylation of H3K27 in FADD promoter by recruiting EZH2. This study is expected to elucidate a new theoretical evidence for the mechanism of TMZ resistance medicated by ATRX in TMZ resistance glioma cells.