Figure 1

Growth on tumor-associated matrices impairs the ability of TSP-1, IP-10, and endostatin to inhibit endothelial cell proliferation. HDMEC were seeded onto plastic or dishes coated with either collagen I, laminin or tenascin C, starved and then stimulated with either 50 ng/ml VEGF alone or in combination with 10, 50 or 250 ng/ml TSP-1 (panel A), 16, 80 or 400 ng/ml IP-10 (panel B) or 20, 100 or 500 ng/ml recombinant endostatin (panel C) for 72 h. Adherent cells were harvested by trypsinization or collagenase treatment (in the case of collagen I coated dishes) and direct cell counts were determined by counting using a Coulter Counter. All bars represent the mean and standard error of triplicate dishes from three independent experiments (n = 9). Within each experiment all samples were normalized to VEGF-induced proliferation and statistical significance (* = p < 0.05, ** = p < 0.001) was determined using unpaired t-tests as compared to VEGF.