骨肉瘤是最常见的原发恶性骨肿瘤，以高侵袭性及极易发生早期转移为特点，预后较差。RNA甲基化—m6A修饰是当前研究热点，越来越多的研究表明m6A修饰在肿瘤的进展中起着重要作用。本团队前期在基因芯片数据库生物信息分析研究中发现m6A去甲基酶ALKBH5表达低的骨肉瘤患者预后较差且5年内易出现转移，并通过miRNA测序及细胞学实验发现ALKBH5介导的m6A修饰可通过调控miR-3144-5p影响骨肉瘤侵袭转移，但具体机制尚未明确。本项目拟从A-to-I编辑水平入手，利用RNA编辑生物指纹法、m6A免疫共沉淀-PCR及荧光素酶报告技术验证ALKBH5介导的m6A修饰通过负向调控A-to-I编辑，影响pri-miR-3144的成熟及其下游靶基因，进而调控骨肉瘤侵袭转移。本研究将通过细胞及动物实验和临床样本进行多重验证。为探寻骨肉瘤肺转移新机制及其靶向治疗提供理论基础。

Osteosarcoma is the most common primary malignant bone tumor with poor prognosis, which is characterised by an awfully high aggressiveness with rapid development of distant metastasis. Methylation of RNA—m6A modification is a hotspot, which has been shown recently to play crucial roles in various tumors. Our previous studies found that osteosarcoma patients of low level of demethylase ALKBH5 had poorer clinical prognosis and more tendence of distant metastasis. With the help of miRNA sequencing and cytological experiment, we confirmed that increasing ALKBH5 suppressed m6A modification and inhibited the invasion and migration of osteosarcoma via miR-3144-5p. However, the precisely mechanism is unclear. We will use RESSq-PCR, MeRIP-qPCR and luciferase reporter assay to test if A-to-I editing, negatively regulated by m6A modification, affects the mature of pri-miR-3144 and its target gene, which is involved in the regulation of invasion and migration of osteosarcoma. And we will verify the relgulation mechanism in vitro and in vivo. The project could provide a new mechanism of metastasis and molecular foundation of targeted therapy in osteosarcoma.