Secretory glycoconjugates of a mucin-synthesizing human colonic adenocarcinoma cell line. Analysis using double labeling with lectins.
Lectins were used to characterize mucin glycoproteins and other secretory glycoconjugates synthesized by a human colon adenocarcinoma-derived cell line which expresses a goblet cell phenotype. Despite being clonally derived, HT29-18N2 (N2) cells, like normal goblet cells in situ were heterogeneous in their glycosylation of mucin. Only wheat-germ agglutinin, which recognizes N-acetylglucosamine and sialic acid residues, and succinylated wheatgerm agglutinin, which binds N-acetylglucosamine, stained the contents of all secretory granules in all N2 goblet cells. The N-acetylgalactosamine binding lectins Dolichos biflorus and Glycine max stained 20% and 21% of N2 goblet cells respectively. Ricinus communis I, a galactose-binding lectin, stained 67% of N2 goblet cells although staining by another galactose-binding lectin, Bandeiraea simplicifolia I, was limited to 19%. Peanut agglutinin, a lectin whose Gal(beta 1-3)GalNAc binding site is not present on mucins produced in the normal colon but which is found on most mucins of cancerous colonic epithelia, stained 68% of the cells. Ulex europeus I, a fucose-binding lectin, did not stain any N2 goblet cells. Four lectins (Lens culinaris, Pisum sativum, Phaseolus vulgaris E, Phaseolus vulgaris L) which recognize sugars normally present only in N-linked oligosaccharides stained up to 38% of N2 goblet cells. The binding of these lectins indicates either both O-linked and N-linked oligosaccharide chains are present on the mucin protein backbone or the co-existence of non-mucin N-linked glycoproteins and O-linked mucins within the goblet cell secretory granule.
Phillips
T E
TE
Division of Biological Sciences, University of Missouri, Columbia 65211.
Frisch
E B
EB
D000230:Adenocarcinoma / Q000032:analysis / Q000378:metabolism*; D003110:Colonic Neoplasms / Q000032:analysis / Q000378:metabolism*; D003594:Cytoplasmic Granules / Q000032:analysis*; D006801:Humans; D037102:Lectins / Q000378:metabolism; D009077:Mucins / Q000032:analysis* / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000032:analysis / Q000378:metabolism
D037102:Lectins; D009077:Mucins