RNA甲基化转移酶METTL3调控lncRNA TUG1的m6A修饰在肝癌侵袭转移中的作用和机制研究

肝癌侵袭转移是影响肝癌疗效重要因素。前期实验表明LncRNA TUG1高表达可促进肝癌的侵袭及转移，与肝癌患者预后不良密切相关。生信分析发现miR-29a是TUG1重要靶点，且TUG1可能通过竞争结合miR-29a促进肝癌侵袭转移。更关键是预实验发现TUG1在肝癌中的表达受到METTL3介导。测序及细胞实验证实降低METTL3表达，TUG1的RNA及其m6A表达降低，肝癌细胞侵袭转移能力减弱。文献及数据分析表明TUG1基因1114位点GGACU修饰区最有可能为m6A修饰位点。据此假设：METTL3介导LncRNA TUG1发生m6A修饰，使TUG1合成增加，进而抑制miR-29a表达，促进肝癌侵袭和转移。本课题将从组织标本、细胞和动物三方面，采用MeRIP、荧光素酶报告等实验方法，阐明METTL3调控LncTUG1/miR-29a信号轴影响肝癌侵袭转移分子机制，为肝癌治疗提供新思路。

The invasion and metastasis of HCC is an important factor affecting the treatment of liver cancer. Our previous experiments showed that high expression of LncRNA TUG1 promoted invasion and metastasis of HCC , which was closely related to the prognosis of patients.Database analysis found that miR-29a is an important target of TUG1, and TUG1 may promote the invasion and metastasis of liver cancer through competition with miR-29a. More critically, the pre-experiment also found that the expression of TUG1 in liver cancer is mediated by the methyltransferase METTL3.We knocked down METTL3 expression in hepatocellular carcinoma cell lines and found that TUG1 expression levels were decreased by sequencing.In vitro experiments showed that knocked down expression of METTL3 resulted in decreased expression of TUG1 RNA and its m6A expression, and reduced ability of invasion and metastasis of HCC cells.We combined the literature and biosignal analysis to find that m6A modification sites exist in the exon region of TUG1.Moreover, Literature and data analysis showed that the GGACU modification region of the 1114 locus of TUG1 gene is most likely to be the m6A modification site.Based on this, we speculate that:METTL3 promotes m6A modification of LncRNA TUG1, which leads to increased synthesis of TUG1, which in turn inhibits miR-29a expression, leading to increased invasion and metastasis of liver cancer.This project will use experimental methods such as MeRIP and luciferase reporter gene to elucidate the molecular mechanism of METTL3 regulating the invasion and metastasis of HCC by mediating LncTUG1 /miR-29a axis.This mechanism provides new ideas for molecular targeted therapy of liver cancer.