Galectin-3 induces endothetial cell morphogenesis and angiogenesis

Increasing evidence suggests that carbohydrate-binding proteins play an ess ential role in tumor growth and metastasis. However, conflicting results on their function in the regulation of cell proliferation and differentiation during angiogenesis have been reported. We have examined the role of galec tin-3 in the regulation of human umbilical vein endothelial cell proliferat ion, differentiation, migration, and neovascularization. Galectin-3, a carb ohydrate-binding protein, with specificity for type 1 and 11 ABH blood grou p epitopes and polylactosamine glycan containing cell surface glycoproteins , is the major nonintegrin-cellular laminin-binding protein. Because galect in-3 expression was shown to be associated in some tumor systems with metas tasis, we questioned whether it induces endothelial cell morphogenesis. Her e we show that galectin-3 affects chemotaxis and morphology and stimulates capillary tube formation of HUV-EC-C in vitro and angiogenesis in vivo. End othelial cell morphogenesis is a carbohydrate-dependent process, as it is n eutralized by specific sugars and antibodies. These findings demonstrate th at endothelial cell surface carbohydrate recognition event(s) can induce a signaling cascade leading to the differentiation and angiogenesis of endoth elial cells.