A SIALYL-LE(X)-NEGATIVE MELANOMA CELL-LINE BINDS TO E-SELECTIN BUT NOT TO P-SELECTIN

The adhesion molecules E-selectin (ELAM-1) and P-selectin (GMP-140/CD6 2) recognize the carbohydrate motives sialyl-Le(x), sialyl-diLe(x), or sialyl-Le(a), though with different affinity. We found that the melan oma cell line NKI-4 bound to E-selectin, but not to P-selectin. This m elanoma cell line did not express sialyl-Le(x), but as positive for si alyl-diLe(x) and sialyl-Le(a). In contrast, 2 other melanoma cell line s, MeWo and SK-MEL-28, expressing either sialyl-diLe(x) or sialyl-Le(a ) on the cell surface, bound neither E-selectin nor P-selectin. Transf ection of the fucosyltransferases Fuc-TIII, Fuc-TIV, and Fuc-TV mediat es cell surface expression of sialyl-Le(x) in many cell lines. We dete cted transcripts of the fucosyltransferases Fuc-TIII and Fuc-TV in 4 m elanoma cell lines despite the absence of cell surface sialyl-Le(x). O ur observations indicate that expression of fucosyl-transferases (Fuc- TIII and -TV) and generation of cell-surface sialyl-diLe(x) are not su fficient to permit adherence to E-selectin or P-selectin. Furthermore, it seems possible that a yet undefined ligand different from sialyl-L e(x), sialyl-diLe(x), or sialyl-Le(a) enables melanoma cells to adhere to E-selectin.