HIF-1α siRNA and TPT inhibit cord formation induced by bFGF. (A) HUVECs transfected with the indicated siRNA were seeded on Matrigel in GF^– medium and treated in the presence or absence of bFGF (20 ng/mL) under normoxic conditions for 16 hours, and cord formation was examined. (B) Length of cords from the experiment shown in panel A was quantified using the Bioquant Image Analysis System as described above. (C) HUVECs were cultured as indicated in panel A under normoxic conditions for 16 hours in the presence or absence of bFGF (20 ng/mL) or TPT (0.1 μM), and cord formation was examined. Results are representative of 4 independent experiments.