Figure 2. Effect of different inhibitory conditions on long-term survival of late outgrowth endothelial progenitor cells and human umbilical vein endothelial cells (HUVECs). Effect of SU5416 on proliferation of OECs (A) and HUVEC (B) in complete angiogenic medium (EGM-2MV). Cells were grown in EGM-2MV control conditions (10 μl dimethyl sulfoxide [DMSO]/ml EGM-2MV), or in the presence of 3, 6, and 10 μM SU5416 added every 48 h. Long-term survival of OECs (C and E) and HUVEC (D and F) was similarly assessed in the presence of other VEGFR-2 Tyrosine kinase inihbitors (TKIs; 10 μM ZM323881, 3 μM KRN951, 4 μM KRN633) and in the presence of inhibitors of the downstream mediators Akt (100 nM Wortmannin), PI 3-kinase (5 μM Ly 294002), and PKC (1 μM bisindolylmaleimide I). All cell counts were performed using the trypan blue exclusion method and a Neubauer counting chamber. The graphs represent the mean±SEM cell number for three independent experiments (OECs derived from three independent (OECs were derived from three different patients, for HUVEC analysis was repeated at least twice) experiments. Student’s t-test for paired data was used for statistical comparison between control and inhibitory conditions at each time point. P values <0.05 were considered significant and are denoted by an asterisk in the figure).