砷是一种广泛存在的致癌物,是肺癌的重要病因。异常调节的miRNA与砷的致癌作用有关,砷诱导的异常调节的miRNA的机制尚未完全阐明。已知N6-甲基腺苷(m6A)修饰调节pri-miRNA加工。然而,m6A介导的pri-miRNA加工是否参与砷的致癌作用尚不清楚.这里,我们发现m6A修饰在亚砷酸盐转化的人支气管上皮BEAS-2B细胞中显著增加(0.5µM亚砷酸盐,16周)。同时,在细胞转化期间,METTL3在第12周和第16周显著上调。扩散,迁移,入侵,通过METTL3敲低m6A水平的降低,抑制了亚砷酸盐转化细胞的非锚定生长。进一步的实验表明,癌基因miR-106b-5p是介导砷诱导的肺癌的潜在必需的m6A靶标。观察到miR-106b-5p在暴露于亚砷酸盐12和16周后上调,METTL3敲低引起的m6A水平降低抑制了亚砷酸盐转化细胞中miR-106b-5p的成熟。更重要的是,miR-106b-5p过表达成功挽救了METTL3敲低诱导的对转化细胞的肿瘤表型的抑制。此外,Basonuclin2(BNC2)被发现是miR-106b-5p的潜在靶标,并通过增强miR-106b-5p成熟被METTL3下调。此外,METTL3抑制剂STM2457通过阻断pri-miR-106b甲基化抑制亚砷酸盐转化的BEAS-2B细胞的肿瘤表型.这些结果表明,m6A修饰通过METTL3/miR-106b-5p/BNC2途径促进亚砷酸盐转化的BEAS-2B细胞的肿瘤表型,为了解砷的致癌作用提供了新的前景。
Arsenic is a widespread carcinogen and an important etiological factor for lung cancer. Dysregulated miRNAs have been implicated in arsenic carcinogenesis and the mechanisms of arsenic-induced dysregulated miRNAs have not been fully elucidated. N6-methyladenosine (m6A) modification is known to modulate pri-miRNA processing. However, whether m6A-mediated pri-miRNA processing is involved in arsenic carcinogenesis is poorly understood. Here, we found that m6A modification was significantly increased in
arsenite-transformed human bronchial epithelial BEAS-2B cells (0.5 µM
arsenite, 16 weeks). Meanwhile, METTL3 was significantly upregulated at week 12 and 16 during cell transformation. The proliferation, migration, invasion, and anchorage-independent growth of
arsenite-transformed cells were inhibited by the reduction of m6A levels through METTL3 knockdown. Further experiments suggest that the oncogene miR-106b-5p is a potentially essential m6A target mediating arsenic-induced lung cancer. miR-106b-5p was observed to be upregulated after exposure to
arsenite for 12 and 16 weeks, and the reduction of m6A levels caused by METTL3 knockdown inhibited miR-106b-5p maturation in arsenite-transformed cells. What\'s more, miR-106b-5p overexpression successfully rescued METTL3 knockdown-induced inhibition of the neoplastic phenotypes of transformed cells. Additionally, Basonuclin 2 (BNC2) was uncovered as a potential target of miR-106b-5p and downregulated by METTL3 via enhancing miR-106b-5p maturation. Additionally, the METTL3 inhibitor STM2457 suppressed neoplastic phenotypes of
arsenite-transformed BEAS-2B cells by blocking pri-miR-106b methylation. These results demonstrate that m6A modification promotes the neoplastic phenotypes of arsenite-transformed BEAS-2B cells through METTL3/miR-106b-5p/BNC2 pathway, providing a new prospective for understanding arsenic carcinogenesis.