O-GlcNAcylation of METTL3 drives hepatocellular carcinoma progression by upregulating MCM10 expression in an m6A-IGF2BP3-dependent manner.

The m6A methyltransferase METTL3 is a key regulator of RNA m6A modification, which plays a critical role in cancer development. Despite the significance of METTL3 in hepatocellular carcinoma (HCC), its post-translational modifications and their functional implications in HCC remain poorly understood. The present study reveals that METTL3 undergoes O-GlcNAcylation, which enhances its stability and promotes HCC progression. Specific O-GlcNAcylation sites (T186/S192/S193) in METTL3 are identified. O-GlcNAc modification reduces METTL3 ubiquitination, thereby increasing protein stability, and enhances its interaction with WTAP, thereby sustaining m6A levels in hepatoma cells. Notably, METTL3 O-GlcNAcylation upregulates the expression of minichromosome maintenance protein 10 (MCM10) by stabilizing its mRNA via an m6A-IGF2BP3-dependent manner. Targeting METTL3 O-GlcNAcylation with designed peptides effectively inhibits HCC growth both in vitro and in vivo. Collectively, our findings provide insights into the regulatory role of O-GlcNAcylation in modulating the m6A epitranscriptome and suggest the potential therapeutic relevance of targeting METTL3 O-GlcNAcylation in HCC.