A novel β1,3-N-acetylglucosaminyltransferase (β3Gn-T8), which synthesizes poly-N-acetyllactosamine, is dramatically upregulated in colon cancer

A new member of the UDP-N-acetylglucosamine: β-galactose β1,3-N-acetylglucosaminyltransferase (β3Gn-T) family having the β3-glycosyltransferase motifs was identified using an in silico method. This novel β3Gn-T was cloned from a human colon cancer cell line and named β3Gn-T8 based on its position in a phylogenetic tree and enzymatic activity. β3Gn-T8 transfers GlcNAc to the non-reducing terminus of the Galβ1-4GlcNAc of tetraantennary N-glycan in vitro. HCT15 cells transfected with β3Gn-T8 cDNA showed an increase in reactivity to both LEA and PHA-L4 in a flow cytometric analysis. These results indicated that β3Gn-T8 is involved in the biosynthesis of poly-N-acetyllactosamine chains on tetraantennary (β1,6-branched) N-glycan. In most of the colorectal cancer tissues examined, the level of β3Gn-T8 transcript was significantly higher than in normal tissue. β3Gn-T8 could be an enzyme involved in the synthesis of poly-N-acetyllactosamine on β1-6 branched N-glycans in colon cancer.