title: Metabolic glycoengineering through the mammalian GalNAc salvage pathway.
abstract: GalNAc is the initial sugar of mucin-type O-glycans, and is a component of several tumor antigens. The aim of this work was to determine whether synthetic GalNAc analogs could be taken up from the medium and incorporated into complex cellular O-glycans. The cell line employed was CHO ldlD, which can only use GalNAc and Gal present in the medium for the synthesis of its glycans. All GalNAc analogs with modified N-acyl groups (N-formyl, N-propionyl, N-glycolyl, N-azidoacetyl, N-bromoacetyl, and N-chloroacetyl) were incorporated into cellular O-glycans, although to different extents. The GalNAc analogs linked to Ser or Thr could be extended by the β3-galactosyltransferase glycoprotein-N-acetylgalactosamine 3β-galactosyl transferase 1 in vitro and in vivo and by α6-sialyltransferase α-N-acetylgalactosaminide-α-2,6-sialyltransferase 1. At the surface of CHO ldlD cells, all analogs were incorporated into sialylated O-glycan structures like those present on wild-type CHO cells, indicating that the GalNAc analogs do not change the overall structure of core-1 O-glycans. In addition, this study shows that the unnatural synthetic GalNAc analogs can be incorporated into human tumor cells, and that a tumor antigen modified by an analog can be readily detected by a specific antiserum. GalNAc analogs are therefore potential targets for tumor immunotherapy.
authors.affiliation: Centre de Biophysique Moléculaire, Université d'Orléans & INSERM, France.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Pouilly
authors.forename: Véronique
authors.initials: V
authors.lastname: Piller
authors.forename: Friedrich
authors.initials: F
authors.lastname: Piller
mesh_terms: D000116:Acetylgalactosamine / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D053898:Biosynthetic Pathways; D016466:CHO Cells; D002240:Carbohydrate Sequence; D045744:Cell Line, Tumor; D006224:Cricetinae; D003412:Cricetulus; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D005434:Flow Cytometry; D005700:Galactosyltransferases / Q000235:genetics / Q000378:metabolism; D005818:Genetic Engineering / Q000379:methods; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D015394:Molecular Structure; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D012799:Sialyltransferases / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D029721:Drosophila Proteins; D006023:Glycoproteins; D011134:Polysaccharides; D005700:Galactosyltransferases; C076385:glycoprotein-N-acetylgalactosamine 3-beta-galactosyltransferase; D012799:Sialyltransferases; C038525:CMP-N-acetylneuraminate-alpha-N-acetylgalactosaminide alpha-2,6-sialyltransferase; D000116:Acetylgalactosamine