Panosialins, inhibitors of an alpha1,3-fucosyltransferase Fuc-TVII, suppress the expression of selectin ligands on U937 cells

Panosialins A and B were isolated as inhibitors of an alpha1,3-fucosyltransferase, Fuc-TVII, which is a key Enzyme in the biosynthesis of Selectin ligands, from culture broth of Streptomyces sp. Panosialins A and B inhibited the Fuc-TVII activity with IC50 values of 4.8 and 5.3 microg/ml, respectively. Panosialin A suppressed expression of Selectin ligands on U937 cells, and inhibited the cell adhesion to immobilized E-selectin-immunoglobulin. Panosialins are the first reported Fuc-TVII inhibitors which can suppress the biosynthesis of Selectin ligands and then inhibit selectin-mediated cell adhesion.