Mechanism of METTL14-mediated mA modification in non-small cell lung cancer cell resistance to cisplatin.

Methyltransferase-like 14 (METTL14) mediates N-methyladenosine (mA) modification to influence cancer progression. This study aims to determine the mechanism of METTL14-mediated mA in non-small cell lung cancer (NSCLC) cell resistance to cisplatin (DDP). METTL14, miR-19a-5p, RBM24, and AXIN1 expressions in NSCLC tissues/cells were determined. DDP-resistant cell line was obtained, followed by the interference of METTL14 expression. NSCLC cells were treated with DDP to establish a drug-resistant cell line, and METTL14 expression in cells was intervened. The IC50 of NSCLC cells to DDP was measured by CCK-8 assay. NSCLC cell proliferation and apoptosis were observed by clone formation assay and flow cytometry. The content of mA in total RNA in tissues and cells of NSCLC patients was detected using mA Methylation Quantification Kit. The expressions of DGCR8-bound pri-miR-19a and mA-modified pri-miR-19a were detected. The binding relationships between miR-19a-5p and RBM24 and RBM24 and AXIN1 were validated using dual-luciferase assay and RNA immunoprecipitation. Finally, mouse xenograft tumor model was established to verify the role of METTL14 in vivo. METTL14 was highly expressed in NSCLC. METTL14 silencing diminished IC50 to DDP, repressed NSCLC cell proliferation, and enhanced apoptosis. METTL14-mediated mA induced recognition and processing of pri-miR-19a by DGCR8, thus promoting the transition of pri-miR-19a to miR-19a-5p, repressing RBM24 expression, reducing the binding of RBM24 and AXIN1, and suppressing AXIN1 transcription. miR-19a-5p overexpression or RBM24/AXIN1 silencing abolished the effect of METTL14 silencing on NSCLC cell resistance to DDP. METTL14 silencing in vivo enhanced the suppressive role of DDP to tumor growth. Collectively, METTL14-mediated mA modification facilitated NSCLC cell resistance to DDP via miR-19a-5p/RBM24/AXIN1 axis. KEY MESSAGES: • METTL14 is highly expressed NSCLC and further increased in DDP-resistant cells. • METTL14 silencing attenuates DDP resistance of NSCLC cells. • METTL14 promotes the nature of pri-miR-19a by upregulating pri-miR-19a m6A level. • miR-19a-5p targets RBM24, thus reducing the binding of RBM24 and AXIN1 and inhibiting AXIN1 transcription. • METTL14 silencing in vivo enhances the suppressive role of DDP to tumor growth.