VWF-deficient cells display increased migration and proliferation in vitro due to increased VEGFR-2 signaling. (A) Representative trajectory plots of siCTL- or siVWF-treated HUVECs migrating into a wounded area for 16 hours, starting at 30 hours after siRNA treatment. The starting point of each cell trajectory is plotted at the center of the graph and the wounded area is to the left of zero on the x-axis. (B) Migration velocity (in micrometers per minute) with or without 50 ng/mL VEGF or with 4μM VEGFR-2 inhibitor SU4312. (C) Directionality of cell migration (Euclidean distance/accumulated distance). (D) Proliferation (in cells per square centimeter) of HUVEC 24 hours after control or siVWF treatment, cultured with or without 100 ng/mL VEGF for 96 hours. Data for siVWF in panel D has been normalized to siCTL-VEGF. siVWF was still effective at 120 hours after siRNA treatment (data not shown). siCTL, nonspecific siRNA-treated cells; siVWF, VWF siRNA-treated cells (n = 3). Error bars = mean ± SEM. *P < .05; **P < .01 (Student t test).