Mechanism of methyltransferase METTL14 mediating m6A modification and regulating SIRT5 expression to promote ferroptosis and repress gastric cancer progression.

OBJECTIVES: Gastric cancer (GC) ranks as the third leading reason of cancer-associated deaths worldwide. This study investigates the mechanism by which the m6A methyltransferase methyltransferase-like 14 (METTL14) enhances ferroptosis and inhibits GC progression through regulation of sirtuin 5 (SIRT5). METHODS: In vitro, AGS cells were treated with pcDNA3.1-METTL14, si-SIRT5 and Ferrostatin-1, while NCI-N87 cells were transfected with si-METTL14. Expression levels of METTL4 and SIRT5 were measured using RT-qPCR and Western blot. GC cell proliferation, migration, and invasion were evaluated through CCK-8, colony formation, and transwell assays. The SRAMP database was used to predict m6A modification sites on SIRT5 mRNA. Interaction between METTL14 and SIRT5 was assessed by RIP assay, with subsequent analysis of SIRT5 m6A modification and SIRT5 mRNA stability via Me-RIP assay and actinomycin D treatment. Reactive oxygen species, Fe(2+), malondialdehyde and superoxide dismutase levels, along with the ferroptosis marker glutathione peroxidase 4, were measured by kit assays and Western blot. Cell death was assessed using the LDH assay. A subcutaneous xenograft tumor model in nude mice was used to confirm METTL14's role in tumor growth suppression. RESULTS: METTL14 expression was significantly reduced in GC cell lines. METTL14 overexpression suppressed GC cell proliferation, invasion, and migration. Mechanistically, METTL14 increased SIRT5 mRNA stability through m6A modification. Silencing of SIRT5 partially counteracted the inhibitory effects of METTL14 overexpression on GC cell malignancy. METTL14 promoted ferroptosis and inhibited GC cell malignancy through SIRT5. In vivo, METTL14 overexpression reduced GC tumor growth by upregulating SIRT5 expression. CONCLUSIONS: METTL14 stabilizes SIRT5 mRNA via m6A modification, upregulating SIRT5 expression and inducing ferroptosis, thereby inhibiting GC progression.