EVI-1诱导miR-124甲基化通过RAS/ERK通路调控AML发生发展的机制研究

AML是一组高度异质性的血液系统肿瘤，其中EVI-1高表达AML约占10%，预后极差，但具体机制尚未明确。有研究表明，EVI-1除了作为转录因子调控靶基因表达，还能够特异性招募甲基转移酶DNMTs，使微小RNA基因启动子甲基化，下调其转录。申请人前期研究发现，在EVI-1高表达白血病细胞株及原代细胞中miR-124-3p表达下降与其启动子过甲基化相关，并且miR-124-3p能够靶向结合原癌基因NRAS抑制其表达。我们推测EVI-1与DNMT3A协同诱导miR-124-3p启动子甲基化使之表达沉默，继而促使其靶基因NRAS过表达并激活下游RAS/ERK通路，导致AML细胞恶性增殖、抑制细胞凋亡。为此，本课题以转基因斑马鱼为模型，从体内外研究EVI-1-miR-124-RAS/ERK调节轴在AML发生发展中的分子机制和作用，为此类AML细化治疗方案、判断预后和去甲基化特异性治疗奠定基础。

AML is a group of highly heterogeneous hematological malignancies. Among them, EVI-1 overexpresses about 10% of AML, and the prognosis is very poor, but the specific mechanism has not been clarified. Foreign studies have shown that in addition to directly regulating gene expression as a transcription factor, EVI-1 can specifically recruit methyltransferases to methylate microRNA gene promoters and down-regulate their transcription.The applicant's previous study found that the decreased expression of miR-124-3p in the high expression leukemia cell lines and primary cells of EVI-1 was related to its promoter hypermethylation, and miR-124-3p could target to bind to the proto-oncogene NRAS to inhibit its expression. We speculated that EVI-1 and DNMT3A could induce the methylation of miR-124-3p promoter to silence its expression, and then promote its target gene NRAS overexpression and activate the downstream RAS / ERK pathway, leading to AML cells malignant proliferation and apoptosis inhibition. Therefore, the molecular mechanism and role of the regulation axis of EVI-1-miR-124-RAS / ERK in the development of AML were studied in vitro and in vivo with transgenic zebrafish as the model in order to lay a foundation for the refinement of treatment plan, prognosis judgment and demethylation specific treatment of such AML.