N ⁶-methyladenosine promotes temozolomide resistance through mRNA stabilization in glioblastoma cells

N ⁶-methyladenosine (m⁶A) regulates nearly every aspect of messenger RNA (mRNA) processing and function, impacting downstream gene expression programs. Changes in m⁶A have been implicated in many different types of cancer, and inhibition of m⁶A installation is emerging as a cancer therapeutic strategy. However, chemoresistance remains a significant clinical challenge in the treatment of glioblastoma (GBM). We established GBM cell culture models of acquired temozolomide (TMZ) resistance, analyzed the role of m⁶A in controlling resistance-associated pathways, and assessed the effects of METTL3 inhibition. We show that m⁶A stabilizes key genes and pathways promoting TMZ resistance, and that METTL3 inhibition can reverse this and restore TMZ sensitivity. These findings highlight that TMZ resistance can occur independent of a glioma stem cell population and that changes in m⁶A need not be driven by changes in METTL3 expression. Collectively, our results suggest that genes associated with TMZ resistance are stabilized by m⁶A methylation even as the majority of the transcriptome remains subject to m⁶A-mediated mRNA decay. Moreover, these data highlight METTL3 inhibition as a promising therapeutic approach to overcoming TMZ resistance in GBM.