Galectin-8 Favors VEGF-Induced Angiogenesis: In Vitro Study in Human Umbilical Vein Endothelial Cells and In Vivo Study in Chick Chorioallantoic Membrane

Background/Aim: Although it has been accepted that the tandem repeat galectin-8 (Gal-8) is linked to angiogenesis, the underlying mechanisms in endothelial cells has remained poorly understood. In this study we aimed to investigate the effect of Gal-8 on selected biological processes linked to angiogenesis in in vitro and in vivo models. Materials and Methods: In detail, we assessed how exogenously added human recombinant Gal-8 (with or without vascular endothelial growth factor - VEGF) affects selected steps involved in vessel formation in human umbilical vein endothelial cells (HUVECs) as well as using the chick chorioallantoic membrane (CAM) assay. Gene expression profiling of HUVECs was performed to extend the scope of our investigation. Results: Our findings demonstrate that Gal-8 in combination with VEGF enhanced cell proliferation and migration, two cellular events linked to angiogenesis. However, Gal-8 alone did not exhibit any significant effects on cell proliferation or on cell migration. The molecular analysis revealed that Gal-8 in the presence of VEGF influenced cytokine-cytokine receptor interactions, HIF-1 and PI3K/AKT signaling pathways. Gal-8 alone also targeted cytokine-cytokine receptor interactions, but with a different expression profile as well as a modulated focal adhesion and TNF signaling. Conclusion: Gal-8 promotes a pro-angiogenic phenotype possibly in a synergistic manner with VEGF.