miR-7受长链非编码RNA FENDRR调控介导胃癌多药耐药的功能与机制研究

多药耐药是胃癌化疗失败的主要原因，但非编码RNA在其中的调控功能与机制仍不清楚。申请人前期发现miR-7在胃癌耐药细胞中表达降低，上调miR-7能增强胃癌细胞化疗敏感性。我们通过比对胃癌耐药细胞与亲本细胞的lncRNA表达谱，发现FENDRR在耐药细胞中显著增高；生物信息学分析显示其含多个miR-7结合位点，且下调FENDRR能促进miR-7表达。我们推测FENDRR可作为ceRNA，与miR-7共同调控胃癌多药耐药。本研究拟通过体内外功能实验，阐明miR-7和FENDRR在胃癌耐药中的功能；通过萤光素酶报告基因实验和紫外交联免疫共沉淀，阐明miR-7与FENDRR的相互关系；联合转录组和蛋白组学技术，筛选miR-7和FENDRR共同调控的耐药相关效应分子和信号通路。本项目通过研究lncRNA-miRNA相互作用新模式，将深化对非编码RNA调控胃癌耐药机制的认识，为逆转胃癌耐药提供新靶点。

Multi-drug resistance is the major cause for the failure of the chemotherapy against gastric cancer. The applicant has conducted a series of studies concerning miR-7 in gastric carcinogenesis and recently found that miR-7 is decreased in gastric cancer multi-drug resistant cell lines and that overexpression of miR-7 in those drug resistant cells could restore the sensitivity to chemotherapy drugs. Through lncRNA microarrays between the gastric drug-resistant cell lines and their parental cell line, we discovered that lncRNA FENDRR is significantly upregulated in gastric cancer multi-drug resistant cell line. Moreover, bioinformatic analysis indicated that FENDRR harbors multiple binding sites for miR-7 and miR-7 expression was increased after FENDRR silencing. In the current project, we aim to clarify the role of miR-7 in gastric cancer multi-drug resistance through in vitro and in vivo functional studies. FENDRR functions as the ceRNA targeting miR-7 will be clarified by luciferase reporter gene assay and UV cross-linking and immunoprecipitation. Additionally, we will screen out the crucial downstream effectors and signaling pathways regulated by FENDRR/miR-7 interaction through cDNA microarray and iTRAQ technique. Through studying the new mode of lncRNA-miRNA interaction, we will deepen the understanding of non-coding RNA regulatory network and provide novel strategy for reversing multi-drug resistance in gastric cancer.