Silencing the Nucleocytoplasmic O-GIcNAc Transferase Reduces Proliferation, Adhesion, and Migration of Cancer and Fetal Human Colon Cell Lines

The post-translational modification of proteins by O-linked beta-N-acetylglucosamine (O-GIcNAc) is regulated by a unique couple of enzymes. O-GIcNAc transferase (OGT) transfers the GIcNAc residue from UDP-GIcNAc, the final product of the hexosamine biosynthetic pathway (HBP), whereas O-GIcNAcase (OGA) removes it. This study and others show that OGT and O-GIcNAcylation levels are increased in cancer cell lines. In that context, we studied the effect of OGT silencing in the colon cancer cell lines HT29 and HCT116 and the primary colon cell line CCD841CoN. Herein, we report that OGT silencing diminished proliferation, in vitro cell survival and adhesion of primary and cancer cell lines. SiOGT dramatically decreased HT29 and CCD841CoN migration, CCD841CoN harboring high capabilities of migration in Boyden chamber system when compared to HT29 and HCT116. The expression levels of actin and tubulin were unaffected by OGT knockdown but siOGT seemed to disorganize microfilament, microtubule, and vinculin networks in CCD841CoN. While cancer cell lines harbor higher levels of OGT and O-GIcNAcylation to fulfill their proliferative and migratory properties, in agreement with their higher consumption of HBP main substrates glucose and glutamine, our data demonstrate that OGT expression is not only necessary for the biological properties of cancer cell lines but also for normal cells.