Galectin-3 inhibitors block VEGF- and bFGF-mediated angiogenesis in vitro. (A) Modified Boyden chamber assay. The effect of galectin-3 inhibitors on VEGF- and bFGF-induced cell migration was evaluated. The cells that migrated from the upper chamber to the lower chamber were counted as described in Fig. 1. (B) Capillary tubule formation assay. HUVEC suspensions premixed with cytokines were plated on solidified matrigel (4.5 mg/ml), and, after 6-h incubation, the extent of capillary tubule formation was evaluated by counting the number of branch points. Representative images from each group are shown in B (ii). Images of cells incubated in media alone (not depicted) were indistinguishable from those incubated in media containing VEGF or bFGF in the presence of β-lactose (Lac). The assays were performed in the absence (Control) and presence of truncated galectin-3 (Gal3C, a dominant-negative inhibitor of galectin-3), full-length galectin-3 (Gal3), 0.1 M β-lactose (Lac, a competing saccharide), and 0.1 M sucrose (Suc, a noncompeting control saccharide). Data are expressed as mean ± SEM (n = 3 or more/group), *, P < 0.01; **, P < 0.05 compared with respective controls incubated without galectin-3 inhibitors (Control) or with a noncompeting saccharide (Suc). Bar, 100 µm. Data are representative of three or more independent experiments.