Taken together, these results show that XIAP is an E3 ubiquitin ligase of OGT, is modified by O-GlcNAc at serine 406, and this modification on XIAP leads to the polyubiquitination and degradation of OGT, resulting in the inhibition of colon cancer cell growth and invasion (Fig. 6). Here, OGT is linked to colonic neoplasm.