METTL7B-driven m6A RNA methylation promotes gemcitabine resistance and tumor progression in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal malignancies, with a five-year survival rate below 12%, primarily due to rapid development of chemoresistance. To identify molecular drivers of drug resistance, we performed integrated transcriptomic, proteomic, and methylation analyses on gemcitabine-resistant PANC-1 GR cells. We identified the methyltransferase-like protein METTL7B as a novel regulator of RNA methylation-mediated resistance in PDAC. Global m6A profiling revealed hypermethylation in resistant cells that correlated with elevated METTL7B expression. Analysis of TCGA and UALCAN datasets confirmed METTL7B upregulation in PDAC tissues, particularly in KRAS-mutant tumors, and its association with poor overall and disease-free survival. Functional assays demonstrated that METTL7B knockdown suppressed proliferation, migration, invasion, and colony formation while restoring gemcitabine sensitivity. Mechanistically, m6A-seq and RNA-seq analyses revealed that METTL7B methylates oncogenic transcripts such as CSF2, CDKN1A, and FoxM1, enhancing their mRNA stability and translation to promote cell-cycle progression and stress adaptation. Network and pathway analyses further linked METTL7B activity to activation of KRAS and STAT3 signaling, indicating its role in PDAC aggressiveness. Collectively, these results identify METTL7B as a key epitranscriptomic regulator of gemcitabine resistance through m6A-dependent stabilization of oncogenic mRNAs and activation of pro-survival pathways. Targeting METTL7B-mediated RNA methylation offers a promising therapeutic strategy to overcome chemoresistance and improve clinical outcomes in PDAC.