FIGURE 4.

Quininib analogues inhibit VEGF-independent angiogenesis in vitro. A, HMEC-1 endothelial cell tubule formation is not affected following 16-h treatment with bevacizumab alone; however, when cells are treated with a combination of recombinant VEGF and bevacizumab, a significant reduction in tubule formation occurs following 16 h. 7,500 cells were seeded in μ-Slide angiogenesis wells and treated in duplicate for each individual experiment, and individual experiments were conducted three times (n = 3). B, representative tubule images of HMEC-1 cells treated with bevacizumab alone or in combination with recombinant VEGF. C, the effects of Q1 and analogue Q8 on HMEC-1 tubule formation are significantly diminished when cells are treated in combination with VEGF. 7,500 cells were seeded in μ-Slide angiogenesis wells and treated in duplicate for each individual experiment, and individual experiments were conducted three times (n = 3). D, tubule images of HMEC-1 cells treated with Q1 or analogue Q8 alone or in combination with VEGF. Statistical analysis was performed by ANOVA and Dunnett's or Bonferroni's post hoc multiple comparison test and Student's t test. Error bars are mean ± S.E. *, p < 0.05; **, p < 0.01; ***, p < 0.001; ns, not significant.