O-GlcNAcylation is associated with the development and progression of gastric carcinoma

O-GlcNAcylation occurs via an O-linked β-N-acetylglucosamine (O-GlcNAc) moiety linked to the side chain hydroxyl of a serine or threonine residue on nucleocytoplasmic proteins. This reaction, which is catalyzed by O-GlcNAc-transferase (OGT), is involved in a variety of human cancers; however, its clinical significance in gastric carcinomas (GC) has been poorly investigated in vivo.

Immunohistochemical staining for O-GlcNAcylation and OGT was performed in 64 primary GCs, 40 gastric adenomas and nonneoplastic tissues adjacent to GCs, including 31 tissues of intestinal metaplasia and 24 normal gastric tissues. Their expressions were also studied in 20 tissues of chronic gastritis according to Helicobacter pylori (H. pylori) infection.

O-GlcNAcylation was expressed in the nucleus and both the nuclear rim and cytoplasm. OGT was strongly expressed in the nucleus and weakly expressed in the cytoplasm. O-GlcNAcylation expression levels were significantly correlated with those of OGT. Their expression levels were progressively increased during the carcinogenesis of GC. O-GlcNAcylation expression was higher in GC with intestinal type, higher pT stage and nodal metastasis, while OGT expression was higher in GC with nodal metastasis. Nuclear O-GlcNAcylation expression was more frequently observed in tumors including GC and adenoma than in nonneoplastic tissues including intestinal metaplasia and normal tissue. Nuclear O-GlcNAcylation expression in GC was closely associated with large size, moderate and poor differentiation, higher pT stage, nodal metastasis and higher clinical stage. In addition, the expression of O-GlcNAcylation and OGT was more elevated in H. pylori-infected chronic gastritis than in chronic gastritis without H. pylori infection.

O-GlcNAcylation expression and its nuclear expression were associated with the carcinogenesis and progression of GC.