HMGA1/hnRNP A2/B1调控MUTYH mRNA稳定性增强胶质母细胞瘤替莫唑胺耐药性的机制研究

替莫唑胺（TMZ）耐药是胶质母细胞瘤（GBM）患者预后极差的重要原因，而线粒体DNA（mtDNA）损伤所致的氧化应激可能参与其调控。申请人前期发现在GBM替莫唑胺耐药株中敲减HMGA1可促进mtDNA损伤，并抑制其TMZ耐药性，而降低活性氧自由基（ROS）水平可逆转这一效应；进一步发现HMGA1可促进碱基切除修复蛋白MUTYH表达，可能与MUTYH mRNA稳定性增强相关。据此提出假说：HMGA1激活HNRNPA2B1基因转录，上调的hnRNP A2/B1蛋白结合并稳定MUTYH mRNA，促进线粒体内MUTYH表达及mtDNA损伤修复，抑制ROS生成，最终增强GBM替莫唑胺耐药性。本研究拟通过基因分段克隆、RNA pull-down、RIP及体内外功能实验，揭示转录及转录后调控参与mtDNA损伤修复调节的全新机制，将为逆转GBM替莫唑胺耐药提供潜在靶点，最终有望改善GBM患者临床预后。

Temozolomide (TMZ) resistance is an important reason for the poor prognosis of patients with glioblastoma (GBM), and oxidative stress caused by mitochondrial DNA(mtDNA) damage may be involved in the regulation of TMZ resistance. We previously found that knockdown of HMGA1 could promote mtDNA damage in temozolomide-resistant GBM cells and inhibit its TMZ resistance, while downregulating ROS level could reverse this effect. Furthermore, it was found that HMGA1 could increase the expression of base excision repair protein MUTYH, which may be related to the enhanced stability MUTYH mRNA. Based on this, we hypothesized that HMGA1 activates HNRNPA2B1 transcription, and the upregulated hnRNP A2/B1 protein binds to MUTYN mRNA and stabilizes it, increasing MUTYH expression in mitochondria and thereby increasing mtDNA damage repair and decreasing ROS generation, and ultimately enhancing GBM temozolomide resistance. To prove this hypothesis, our team will use DNA segment cloning technology, RNA pull-down, RIP, and in vivo and in vitro experiments to unravel a novel mechanism of how transcription and post-transcriptional regulation are involved in mtDNA damage repair regulation, which will provide potential targets for reversing GBM temozolomide resistance, and ultimately improve the prognosis of GBM patients.