Background: Methyltransferase like 3 (METTL3) is an RNA methyltransferase implicated in mRNA biogenesis, decay, and translation control through N⁶-methyladenosine (m⁶A) modification.
Methods: To find new treatment strategies for lung cancer and to elucidate the mechanism underlying the phenomenon, we treated the human lung cancer cell lines A549 and H1299 to investigate the effect of METTL3 on lung cancer. 
Results: We observed that knockdown of METTL3 inhibited the survival and proliferation of A549 and H1299 cells. The migration and proliferation of both cell lines were significantly decreased, and the apoptosis was induced in comparison with control cells. These results were further confirmed by the transfection of miRNA of METTL3 increased the Bax/Bcl-2 ratio in A549 and H1299 cells, which is a sign that mitochondrial apoptotic pathway was triggered. The PI3K/Akt pathway is implicated in cell growth and survival and we also observed that knockdown of METTL3 changed the expression and phosphorylation of proteins of PI3K signaling pathway members. Further, our results demonstrated that miR-600 inhibited the expression of METTL3 and reversed the positive effect of METTL3 on NSCLC progression, indicating an miR-600/METTL3 pathway in NSCLC. 
Conclusion: These data suggested that miR-600 inhibited lung cancer via down-regulating METTL3 expression, and knockdown of METTL3 might be used as a novel strategy for lung cancer therapy.
Keywords: METTL3, miRNA, lung cancer, A549, H1299, apoptosis, PI3K pathway