FOSL1/MGC32805靶向募集RBM5介导mFAS/△FAS异构体表达失衡诱导结直肠癌耐药的新机制

可变剪接（AS）作为肿瘤发生驱动器介导基因转录复杂性和蛋白多样性。课题组发现MGC32805介导结直肠癌（CRC）耐药与FAS-AS事件mFAS/△FAS表达失衡相关，并发现mFAS-CASP8及△FAS-PIGN间3D互作位点；找到MGC32805匹配FAS前体及靶向OCRE域招募剪接因子RBM5结构；预测到FOSL1-TGACTCAT元件特异识别MGC32805启动子。但FOSL1/MGC32805介导mFAS/△FAS表达失衡调控CRC耐药机制尚需阐明。本项目拟：①明确MGC32805介导mFAS/△FAS双信号轴调控CRC耐药新途径；②解析MGC32805作为分子支架特异结合FAS前体协同招募RBM5介导mFAS/△FAS表达新方式；③阐明FOSL1转录激活MGC32805通过FAS-AS介导CRC耐药新机制。本研究为挖掘LncRNA-AS事件调控CRC耐药网络提供新靶点和新思路。

Alternative splicing (AS), known as “tumor driver”, mediated complicated gene transcriptions and multiple proteins at RNA post-transcriptional level. We demonstrated that LncRNA-MGC32805 acts its functions involving in multi-drug resistance, significantly associated with disproportion expression between mFAS and △FAS alternative splice isomer upon LncRNAs-mRNAs microarrays. We further evaluated and found the directly interacted amino acids of mFAS-CASP8 or △FAS-PIGN based on their 3D structures. Further bioinformatics analysis explored MGC32805 precisely matched the binding ESE sites of FAS pre-mRNA and identified MGC32805 recruited RBM5 protein by recognizing the critical amino acids of the OCRE domain. However, the underlying molecular mechanisms of FOSL1/MGC32805 regulating CRC multi-drug resistance through the disproportion expression of mFAS/△FAS have not been clarified and need to be further investigated. In order to verify this hypothesis, the project proposed to ①confirm the novel pathways between mFAS/△FAS double signaling axis and MGC32805 mediating CRC multi-drug resistance; ②identify the alternative splicing pattern of MGC32805, the critical molecular scaffold, specifically binding with FAS pre-mRNA and recognizing the OCRE domain of RBM5; ③unveil the uncovered molecular mechanism of MGC32805 being activated by transcriptional factor FOSL1 mediating CRC multi-drug resistance process through FAS-AS pattern. Our project aims to investigate a novel network of LncRNA-AS mediating CRC multi-drug resistance, and provide new targets and biomarkers for CRC treatment.