DS500 and fucoidan inhibit Sema3A and VEGF₁₆₅ cell binding and function. (A) DS500 and fucoidan block Sema3A binding to HUVECs. Cells were incubated with DS500 (●; 0-8 μg/mL), heparin (▲), ChoSul A (■), dextran (♦), or fucoidan (○; 8 μg/mL), washed (1 M NaCl), and incubated with Sema3A/Fc. Bound Sema3A/Fc was detected by flow cytometry. (B,C) DS500 and fucoidan inhibit Sema3A-induced lamellipodia retraction in HUVECs. After preincubation with or without DS500 or fucoidan, HUVECs were allowed to attach onto fibronectin-coated slides, and then incubated with or without Sema3A/Fc. (B) Representative images. Magnification 100×. (C) Average retraction scores (± SD of 4 fields). *P < .01. (D) DS500 and fucoidan block VEGF₁₆₅ binding to HUVECs. Bound VEGF₁₆₅was detected by flow cytometry. Experimental conditions as described in panel A. (E) DS500 and fucoidan inhibit VEGF₁₆₅-induced proliferation of HUVECs. Cells were cultured (3 days) with ChoSul A, DS500, or fucoidan in the presence of VEGF₁₆₅ (25 ng/mL); proliferation was measured by ³H-thymidine uptake. Results are expressed as mean cpm/culture (± SD of triplicate cultures).