Fucosylation of disaccharide precursors of sialyl Lewis(X) inhibit selectin-mediated cell adhesion

We showed previously that HL-60 and F9 mouse embryonal carcinoma cells will take up and deblock peracetylated Gal beta 1-4GlcNAc beta-O-naphthalenemethanol (Gal beta 1-4GlcNAc-NM) and use the disaccharide as a primer of oligosaccharide chains (Sarkar, A. K., Fritz, T. A., Taylor, W. H., and Esko, J. D. (1995) Proc. Natl. Acad. Sci. U. S. A. 92, 3323-3327). We now report that another disaccharide, acetylated GlcNAc beta 1-3Gal-naphthalenemethanol (GlcNAc beta 1-3Gal-NM), has even greater potency and that both compounds will inhibit sialyl Lewis(X) (sLe(x))-dependent cell adhesion. When fed to U937 cells, acetylated forms of Galpl-1GrlcNAc-NM and GlcNAc beta 1-3Gal-NM primed oligosaccharides in a dose-dependent manner. Analysis of compounds assembled on Gal beta 1-4GlcNAc-NM showed only one product, namely Gal beta 1-4(Fuc alpha 1-3)GlcNAc-NM. In contrast, Glc-NAc beta 1-3Gal-NM generated Gal beta 1-4GlcNAc beta 1-3Gal-NM, Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal-NM, NeuAc alpha 2-3Gal beta 1-4GlcNAc beta 1-3Gal-NM, and NeuAc alpha 2-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal-NM. Both compounds decreased the incorporation of [H-3]fucose into cellular glycoconjugates, without affecting the incorporation of [H-3]mannosamine, a precursor of sialic acid residues. Moreover, the overall extent of sialylation was not affected based on the reactivity of cells to fluorescein isothiocyanate-conjugated Maackia amurensis lectin. Priming inhibited expression of sLe(x) on cell surface glycoconjugates, which reduced E-selectin-dependent cell adhesion to tumor necrosis factor-cu-activated human umbilical vein endothelial cells. GlcNAc beta 1-3Gal-NM and Gal beta 1-4Glc-NAc-NM represent starting points for making enzyme-specific, site-directed inhibitors of glycosyltransferases that could act in living cells.