title: Expression of core 2 beta-1,6-N-acetylglucosaminyltransferase in a human pancreatic cancer cell line results in altered expression of MUC1 tumor-associated epitopes.
abstract: Many tumor-associated epitopes possess carbohydrate as a key component, and thus changes in the activity of glycosyltransferases could play a role in generating these epitopes. In this report we describe the stable transfection of a human pancreatic adenocarcinoma cell line, Panc1-MUC1, with the cDNA for mucin core 2 GlcNAc-transferase (C2GnT), which creates the core 2 beta-1,6 branch in mucin-type glycans. These cells lack endogenous C2GnT activity but express a recombinant human MUC1 cDNA. C2GnT-transfected clones expressing different levels of C2GnT were characterized using monoclonal antibodies CC49, CSLEX-1, and SM-3, which recognize tumor-associated epitopes. Increased C2GnT expression led to greatly diminished expression of the CC49 epitope, which we identified as NeuAcalpha2,6(Galbeta1,3)GalNAcalpha-Ser/Thr in the Panc1-MUC1 cells. This was accompanied by the emergence of the CSLEX-1 epitope, sialyl Lewis x (NeuAcalpha2,3Galbeta1,4(Fucalpha1,3)GlcNAc-R), an important selectin ligand. Despite this, however, the C2GnT transfectants could not bind to selectins. Increased C2GnT expression also led to masking of the SM-3 peptide epitope, which persisted after the removal of sialic acid, further suggesting greater complexity of the core 2-associated O-glycans on MUC1. The results of this study suggest that C2GnT could play a regulatory role in the expression of certain tumor-associated epitopes.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA.
authors.forename: P V
authors.initials: PV
authors.lastname: Beum
authors.forename: J
authors.initials: J
authors.lastname: Singh
authors.forename: M
authors.initials: M
authors.lastname: Burdick
authors.forename: M A
authors.initials: MA
authors.lastname: Hollingsworth
authors.forename: P W
authors.initials: PW
authors.lastname: Cheng
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000912:Antibodies, Neoplasm / Q000276:immunology; D002240:Carbohydrate Sequence; D002417:Cattle; D000939:Epitopes / Q000032:analysis; D015972:Gene Expression Regulation, Neoplastic; D006031:Glycosylation; D006801:Humans; D008969:Molecular Sequence Data; D018396:Mucin-1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009077:Mucins / Q000276:immunology; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics*; D019158:N-Acetylneuraminic Acid / Q000276:immunology / Q000378:metabolism; D009844:Oligosaccharides / Q000276:immunology; D010190:Pancreatic Neoplasms; D010455:Peptides / Q000276:immunology; D011134:Polysaccharides / Q000276:immunology; D000080506:Sialyl Lewis X Antigen; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D000912:Antibodies, Neoplasm; C091202:B72.3 antibody; D000939:Epitopes; D018396:Mucin-1; D009077:Mucins; D009844:Oligosaccharides; D010455:Peptides; D011134:Polysaccharides; C116591:SM3-MUC1 peptide; D000080506:Sialyl Lewis X Antigen; D017351:N-Acetylglucosaminyltransferases; C053024:beta-1,3-galactosyl-O-glycosyl-glycoprotein beta-1,6-acetylglucosaminyl transferase; D019158:N-Acetylneuraminic Acid