Molecular mechanism of METTL7B-mediated m6A modification in ferroptosis of non-small cell lung cancer cells

Abstract

Nonsmall cell lung cancer (NSCLC) is the predominant form of lung cancer. Ferroptosis is a novel therapeutic target against treatment resistance in NSCLC. However, its regulation by m6A RNA modification remains incompletely elucidated. m6A RNA modification mediates mRNA stability, translation, and splicing to target transcripts. Methyltransferase like 7B (METTL7B) has been implicated in tumor progression, but its role in NSCLC ferroptosis via m6A modification has not been reported. We aimed to investigate the mechanism of METTL7B-mediated m6A modification in NSCLC cell ferroptosis. NSCLC cells (SK-MES-1/PC9/H1975/A549) and normal cells (BEAS-2B) were cultured. The expression of METTL7B, long non-coding RNA 02159 (LINC02159), and aryl hydrocarbon receptor nuclear translocator-like 2 (ARNTL2) was determined. After METTL7B knockdown, cell viability was measured by MTT assay; ferroptosis-related factors were analyzed. m6A quantification was performed. m6A enrichment on LINC02159 was analyzed. The interaction between LINC02159 and KAT2A was verified. KAT2A and H3K27ac enrichment on the ARNTL2 promoter was detected. The roles of LINC02159 and ARNTL2 were validated. METTL7B, LINC02159, and ARNTL2 were upregulated in NSCLC cells compared to BEAS-2B cells. METTL7B knockdown increased iron ions, reactive oxygen species, and malondialdehyde levels and decreased cell viability, superoxide dismutase, and glutathione levels. METTL7B potentially upregulated LINC02159 expression through m6A modification. LINC02159 may recruit KAT2A to enhance H3K27ac enrichment on the ARNTL2 promoter, thereby promoting ARNTL2 expression. Overexpression of LINC02159 or ARNTL2 partially reversed the pro-ferroptotic effects of METTL7B knockdown on NSCLC cells. In conclusion, METTL7B inhibits ferroptosis in NSCLC cells via the LINC02159/KAT2A/ARNTL2 axis in an m6A-dependent manner.