DNA methylation and m6A RNA modification regulate RBM12 overexpression to promote lung cancer stemness and progression

RNA-binding motif protein 12 (RBM12) has recently been implicated in tumor progression, immune regulation, and cancer stem cell biology. However, its expression pattern, regulatory mechanism, and functional role in lung adenocarcinoma (LUAD) remain unclear. This study aimed to investigate the clinical significance, epigenetic regulation, and biological function of RBM12 in LUAD. Pan-cancer expression, protein abundance, genetic alteration, DNA methylation, survival, immune infiltration, and drug sensitivity analyses of RBM12 were performed using public cancer datasets, including TCGA, CPTAC, cBioPortal, and related bioinformatic platforms. Functional enrichment analyses were conducted to identify RBM12-associated biological processes and signaling pathways. Potential m6A regulators of RBM12 were predicted, and the relationship between METTL14 and RBM12 was further examined. In vitro experiments were performed in LUAD cells to validate RBM12 expression, METTL14-mediated regulation of RBM12 mRNA stability, and the effects of RBM12 knockdown on cell proliferation, migration, apoptosis, and Wnt/stemness-related gene expression. RBM12 was broadly dysregulated across human cancers and showed cancer-type-dependent prognostic value. In LUAD, RBM12 was significantly upregulated at both mRNA and protein levels. RBM12 expression was associated with pathological features, TP53 mutation status, immune-cell infiltration, and drug-response profiles. DNA methylation analysis suggested that reduced RBM12 methylation may contribute to its upregulation in lung cancer. Functional enrichment analysis indicated that RBM12-associated genes were mainly involved in RNA processing, chromatin regulation, DNA repair, immune checkpoint-related pathways, and Wnt signaling. Mechanistically, METTL14 was identified as a potential upstream regulator of RBM12. METTL14 knockdown reduced RBM12 mRNA expression and accelerated RBM12 mRNA decay, suggesting that METTL14 positively regulates RBM12 mRNA stability. Functionally, RBM12 knockdown suppressed LUAD cell proliferation and migration, reduced the expression of Wnt/stemness-related genes including CTNNB1, SOX2, and MYC, and promoted apoptosis. This study identifies RBM12 as a dysregulated RNA-binding protein in LUAD and suggests that RBM12 may contribute to lung cancer progression by promoting cell growth, migration, survival, and Wnt/stemness-associated signaling. METTL14-mediated regulation of RBM12 mRNA stability may represent an important mechanism controlling RBM12 expression. These findings highlight the METTL14–RBM12 axis as a potential biomarker and therapeutic target in LUAD.