METTL16-mediated m6A modification of LYRM2 drives breast cancer progression by inducing CD8+ T cell dysfunction via Glycolysis.

CD8+ T cells in the tumor microenvironment suppress breast cancer (BRCA) progression. Although LYRM2 correlates with immune cell infiltration, its crosstalk mechanism with CD8+ T cells in BRCA remains unclear. We integrated bioinformatics, clinical samples, and cellular experiments to analyze the potential role of LYRM2 in BRCA and CD8+ T cell infiltration. In a co-culture system of BRCA cells and CD8+ T cells, lactate dehydrogenase release assay, carboxyfluorescein succinimidyl ester proliferation assay, and ELISA assessed CD8+ T cell cytotoxicity and proliferation. Colony formation, WB, and Transwell assays evaluated BRCA cell malignant phenotypes. GSEA identified LYRM2-regulated pathways. Seahorse XFe96 Analyzer and assay kits measured glycolysis parameters. Bioinformatics analysis predicted regulator proteins of LYRM2 m6A modification; RNA pull-down, RIP, MeRIP-qPCR and RNA stability assay validated binding specificity and methylation levels. A mouse allograft tumor model was established to evaluate CD8+ T cell infiltration and BRCA progression in vivo. In BRCA, overexpressed LYRM2 correlated with poorer prognosis and decreased CD8+ T cell infiltration. Knocking down LYRM2 enhanced CD8+ T cell antitumor activity and inhibited the malignant progression of BRCA cells. METTL16-mediated m6A modification of LYRM2 suppressed CD8+ T cell function by reshaping glucose metabolism, thereby promoting BRCA progression. In vivo, the METTL16/LYRM2 axis weakened CD8+ T cell function and accelerated tumor growth. METTL16 promotes stable expression of LYRM2 via m6A methylation, thereby activating glycolysis pathways to induce CD8+ T cell dysfunction, which finally drives BRCA progression. The finding identified LYRM2 as a potential target for BRCA immunotherapy.