新的lncRNA-RAG1促进自噬降低胃癌细胞化疗药物敏感性的机制研究

It is a major reason of poor prognosis in gastric cancer patients that tumor cell is not sensitive for chemotherapy drugs. It involves complicated mechanisms and multiple pathways. Autophagy and lncRNA may play an important role to regulate tumor cells chemosensitivity. We found that 5-FU induced lncRNA-RAG1 promoted autophagy and reduced chemosensitivity in gastric cancer cells. But the mechanisms of how 5-FU induced the expression oflncRNA-RAG1 andlncRNA-RAG1 promote autophagy are still unknown. This project focuses on the molecular mechanisms of the up-regulated expression oflncRNA-RAG1 by the demethylase activated by 5-FU and the autophagy occurs promoted by AMPK signal pathway which is activated bylncRNA-RAG1. RNA-Seq, CRISPR/dCas9 interference and CRISPR/dCas9-activator systems and dChIRP are the major methods to explore above problems. To analyze the correlation between the expression of lncRNA-RAG1 to the curative effect of chemotherapy and survival time is the second aim. There are Important scientific and clinical significance to investigate the key role and mechanism of the chemosensitivity of gastric cancer cells regulated by autophagy induced by 5-FU through promoting the expression of lncRNA-RAG1.

胃癌细胞对化疗药物敏感性低是胃癌预后差的主要原因，其机制复杂，涉及多个多途径。探索其可能机制对于提高化疗疗效有重要意义。项目组前期在胃癌细胞中发现并鉴定了5-FU诱导的lncRNA-RAG1，能促进自噬发生，降低胃癌细胞对5-FU的敏感性，但5-FU如何激活lncRNA-RAG1表达及lncRNA-RAG1如何调控自噬发生的机制尚不明确。本项目拟通过高通量测序、CRISPR 编辑系统、结构域特异性RNA纯化的染色质分离（dChIRP）、PDOX模型等技术，重点研究5-FU通过激活甲基转移酶降低lncRNA-RAG1表达、lncRNA-RAG1通过激活AMPK信号通路促进自噬发生的分子机制及lncRAG表达量与化疗疗效、患者生存期的相关性，阐明5-FU诱导的lncRNA-RAG1和自噬在调控肿瘤细胞化疗敏感性的重要作用和机制，具有重要的科学意义和临床意义。

胃癌细胞对化疗药物敏感性低是胃癌预后差的主要原因，其机制复杂，涉及多个多途径。探索其可能机制对于提高化疗疗效有重要意义。本项目阐明5-FU诱导lncRNA-RAG1表达的分子机制及lncRNA-RAG1调控自噬的分子机制，揭示lncRNA-RAG1在5-FU诱导肿瘤细胞保护性自噬过程中的重要生物学功能。同时鉴定出了包含lncRNA-RAG1在内的数条lncRNA（linc000701、linc01614、lncRNACR749391及linc00483）和hsa-miR-653-5p在胃癌中的作用机制，证实5-FU能通过激活去甲基化酶促进lncRNA表达，并进一步促进细胞自噬的发生并因此降低肿瘤细胞对于5-FU的敏感性，hsa-miR-653-5p通过靶向PTEN促进胃癌细胞迁移，所有研究均在细胞、动物、临床三个层面探索其具体机制。并且利用课题组优势，围绕本课题研究基础（lncRNA、自噬、甲基化等），联系肠道微生态在消化系统肿瘤（胃癌、肠癌）以及炎症性肠病的作用，进行了课题延伸，将学术成果尽可能地转化为临床关注的问题（比如早癌筛查、炎癌转化、肠道微生态等），具有一定的社会效益和临床转化价值。