Fig. 5. Knockdown of p190B prevents PMA- and FGF-induced capillary tube formation in Matrigel. (A) HUVECs transfected with control, A1, A2, B1, B3 or MT1-MMP siRNA were seeded on Matrigel. The formation of PMA- and FGF-induced capillary tubes was quantified after 6 hours at 37°C by counting the number of tubes. The means and s.e. of the percentage of tubes per field relative to the control are shown (n=3). The formation of tubes induced by PMA or FGF was significantly inhibited (P<0.05 in Student's t-test) in p190B- and MT1-MMP-KD cells when compared with control (control-siRNA-transfected cells). (B) Representative photomicrographs of capillary-like structures from control-, A1- or B1-siRNA-transfected HUVECs cultured on Matrigel for 6 hours in the presence of PMA are shown.