Galectin-1 modulates human melanoma cell adhesion to laminin

Galectins constitute a gene family of beta-galactoside-specific lectins that show high homology in their carbohydrate-binding site. They have been postulated to be involved in many biological events, but their specific functions are not yet well defined. Galectin-1 is a laminin binding protein that recognizes poly-N-acetyllactosamine chains on this major basement membrane glycoprotein. In this study, we analyzed the possibility that galectin-1 could modulate interactions between human melanoma cells and laminin. We demonstrated that A375 and A2058 cell lines express galectin-1 both intracellularly and on the cell surface. In an in vitro assay, recombinant galectin-1 increased melanoma cell attachment to laminin in a dose-dependent manner. This effect was abolished by lactose. Anti-galectin-1 inhibited adhesion of melanoma cells to laminin in a dose-dependent fashion. However, neither galectin-1 nor anti-galectin-1 antibody affected melanoma cell spreading on laminin in vitro. These data indicate that galectin-1 might participate in melanoma cell adhesion to laminin and therefore could be a modulator of invasion and metastasis.