RBM15介导ECT2的m6A甲基化修饰抑制胃癌进展及增强5-FU化疗敏感性的分子机制研究

复发转移及5-FU耐药是影响胃癌患者预后的重要因素，因此筛选指示胃癌进展及5-FU化疗敏感性的生物标志物具有显著临床意义。应用CD-DST技术筛选5-FU敏感及不敏感胃癌组织再结合RNA-seq结果分析，发现N6甲基腺苷（m6A）甲基转移酶RBM15在5-FU敏感组中高表达。前期分析发现RBM15与上皮细胞转化序列2癌基因（ECT2）显著正相关，潜在调控EMT信号通路抑制胃癌进展和增强5-FU化疗敏感性，但其分子机制尚未明确。本研究将利用双荧光素酶报告基因系统、MeRIP-seq、PDX小鼠等验证RBM15通过靶向调控ECT2 pre-mRNA的m6A甲基化修饰上调ECT2的表达，抑制EMT信号通路，调控胃癌进展及5-FU化疗敏感性的原创性推论。该研究将揭示m6A表观遗传修饰在胃癌进展及化疗敏感性的作用机制，对胃癌患者预后评估及指导临床合理应用5-FU化疗方案具有重要指导意义。

Recurrence, metastasis and chemotherapy resistance remains the major causes of prognosis of gastric cancer (GC) patients, which implies the urgency of identifying biomarkers of GC progression and 5-FU chemosensitivity. 5-FU sensitive and non-sensitive GC tissues were screened by Collagen Gel Droplet-embedded Culture Drug Sensitivity Test (CD-DST) and further sequenced by RNA-seq analysis, which revealed that RBM15，a N6 methyladenosine (m6A) methyltransferase，was highly expressed in 5-FU sensitive group. Preliminary analysis showed that RBM15 was significantly positively correlated with ECT2, potentially regulating Epithelial-Mesenchymal Transition (EMT) pathway to inhibit GC progression and enhance 5-FU chemosensitivity, but its molecular mechanism remains unclear. In this project, we will employ the CD-DST, Luciferase reporter assays, MeRIP-seq and Patient derived Xenografts (PDX) model etc. to verify the hypothesis that RBM15 directly mediates ECT2 expression and m6A modification of ECT2 pre-mRNA, which inhibits the EMT pathway resulting in GC progression and 5-FU chemotherapy sensitivity. Taken together, our findings will reveal the mechanism of m6A epigenetic modification in GC progression and chemosensitivity, and furthermore，it will provide guidance for the prognosis assessment and the rational application of 5-FU chemotherapy.