GFPT1 and hepatocellular carcinoma: Treatment with OSMI-1, a potent inhibitor of O-GlcNAc transferase (OGT), led to a significant decrease in O-GlcNAcylation levels, suggesting that GFAT1 promotes UDP-GlcNAc biosynthesis and O-GlcNAc modification in hepatoma cells in an enzyme activity-dependent manner (Fig. 3H).