ESRP1选择剪接circRNA介导人上皮性卵巢癌EMT机制研究

Epithelial mesenchymal transition (EMT) is a critical event in the invasion and metastasis of epithelial ovarian cancer (EOC). ESRP1 is a newly discovered RNA binding protein (RBP), which acting as an alternative splicing (AS) factor. We have previously confirmed that ESRP1 was related to the prognosis of EOC, and ESRP1 could mediate the EMT process by alternative splicing the key factors in this process, thus affecting the invasion and metastasis of EOC ultimately. Recent studies have confirmed that cyclic RNAs (circRNAs) play important roles in the EMT of cancer. A few studies have suggested that RBPs can regulate circRNA formation through AS and affect the progression of cancers. However, report about the ESRP1-regulated circRNAs formation in EOC has not been seen so far. This project will focus on two frontier hotspots: circRNA and AS. On the basis of the existing research, we will screen and identify the target circRNAs of ESRP1 by high throughput sequencing, and try to construct the preliminary model of ESRP1-regulated circRNAs formation in EOC. At the same time, the roles of these target circRNAs in EMT and the specific ESRP1-regulated mechanism in EOC will be investigated by clinical tissue samples, in vitro and in vivo experiments, which will provide a novel therapeutic strategy for patients with EOC.

上皮间质转化（EMT）为上皮性卵巢癌（EOC）侵袭与转移中关键事件。ESRP1是近年新发现的RNA结合蛋白（RBP）与选择剪接（AS）因子。申请人前期已证实ESRP1与EOC预后相关，并可通过对EMT关键因子的选择剪接介导该过程，最终影响EOC侵袭与转移。新近研究证实环状RNA(circRNA)在肿瘤EMT中扮演重要角色。少量研究提示RBP可通过AS介导circRNA产生并影响肿瘤进展,但至今未见EOC中ESRP1选择剪接circRNA相关报道。本课题拟聚焦circRNA及AS两大前沿热点，在既有基础上通过高通量测序筛选及鉴定ESRP1靶circRNA，尝试初步构建ESRP1介导circRNA形成调控模型。同时，在临床组织样本资料、体外及体内实验多个层面探讨这些靶circRNA在EOC EMT过程中的相关作用及ESRP1对其具体调控机制，以图为临床EOC诊治提供新的切入点。

肿瘤转移是导致上皮性卵巢癌（EOC）患者高复发率和高病死率的重要原因，上皮间质转化（EMT）已被证实是EOC侵袭与转移的关键机制之一。上皮剪接调节蛋白1（ESRP1）是一种特异性表达于上皮细胞的RNA结合蛋白，并且和环状RNA（circRNA）的生物发生具有密切的关系。本项目探索了ESRP1调控的circRNA在EOC细胞EMT及其转移过程中的作用和机制。研究发现，ESRP1可以维持EOC细胞的上皮表型，促进EOC细胞增殖，但抑制其侵袭、迁移；高通量circRNA测序结果显示，ESRP1促进circCHSY1、circPAFAH1B2和circUBAP2等一系列circRNA的表达，并且在这些circRNA两侧翼内含子序列均具有大量ESRP1结合基序；此外，生信分析发现circCHSY1、circPAFAH1B2和circUBAP2与多个RNA结合蛋白具有结合潜能，其中IGF2BP2和FBL高表达与EOC患者较短生存期相关，而RBM47表达与EOC患者较长生存期相关；高通量mRNA测序结果显示ESRP1调节大量EMT相关基因的表达，其中EGR1、EPHB2、IRS2和MRC2高表达与EOC患者较短的生存期相关，而GMNN表达与EOC患者较长的生存期相关；另外，EOC的m6A高水平患者具有较差的预后，且circPAFAH1B2靶蛋白HNRNPA2B1可以升高EOC细胞整体m6A水平，并促进EOC细胞增殖、迁移和侵袭。本课题的研究成果探索了ESRP1调控的circRNA在介导RNA结合蛋白调控m6A修饰并促进肿瘤转移的作用和机制，揭示了ESRP1、HNRNPA2B1、circCHSY1、circPAFAH1B2和circUBAP2等蛋白或非编码RNA可能成为治疗EOC转移的潜在靶点。