Intracellular inhibition of blood group A glycosyltransferase.
We report the intracellular inhibition of blood group A N-acetylgalactosaminyltransferase in the human colorectal carcinoma cell line HT29 by 3-amino-3-deoxy-[Fucalpha(1-2)]Galbeta-O(CH2)7CH3. Inhibition was demonstrated with a novel capillary electrophoresis assay that monitored decreased intracellular conversion of fluorescently labelled Fucalpha(1-2)Gal-R acceptor to the corresponding A epitope, GalNAcalpha(1-3)[Fucalpha(1-2)]Galbeta-R. Growth of HT29 cells with either the amino-inhibitor or a competitive substrate, Fucalpha(1-2)Galbeta-O(CH2)7CH3, also resulted in decreased expression of blood group A determinants on cell-associated glycoproteins, as detected by immunoprecipitation analysis using A-specific monoclonal antibodies. Furthermore, exposure of these cells to the amino-inhibitor or competitive substrate resulted in significant reduction of cell-surface expression of blood group A determinants. As integrin alpha3beta1, a cell-surface receptor mediating cell-cell and cell-extracellular matrix interactions, was shown previously to be a major carrier of blood group A determinants on HT29 cells, the studies described herein highlight the potential usefulness of these compounds for elucidating the role of blood group A determinants in biological phenomena.
Laferté
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Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada. laferte@duke.usask.ca
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Sujino
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D000911:Antibodies, Monoclonal / Q000378:metabolism; D004187:Disaccharides / Q000494:pharmacology; D019075:Electrophoresis, Capillary / Q000379:methods*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D005434:Flow Cytometry; D006801:Humans; D007700:Kinetics; D008956:Models, Chemical; D017350:N-Acetylgalactosaminyltransferases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000737:chemistry; D009844:Oligosaccharides / Q000494:pharmacology; D011233:Precipitin Tests; D012710:Serum Albumin, Bovine / Q000378:metabolism; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D004187:Disaccharides; D000939:Epitopes; D009844:Oligosaccharides; D012710:Serum Albumin, Bovine; D017350:N-Acetylgalactosaminyltransferases; C003742:UDPgalactosamine-galactose acetylgalactosaminyltransferase