Figure 3.

Gene silencing of cathepsin B induces robust tube formation. (A) BRECs were infected with a retrovirus encoding either the siRNA for one of three regions of cathepsin B or an empty vector (EV). Total cell lysates were made and subjected to Western blot analysis using an anti-cathepsin B antibody. The blot was reprobed with an anti-RasGAP antiserum to verify equivalent protein loading in all the lanes. (B) BRECs infected with either an siRNA for cathepsin B or an EV were plated within a collagen sandwich gel, and then medium containing either 2.5 ng/ml VEGF or 40 μM CBI was added. After 5 d in culture at 37°C, three randomly selected fields were photographed, and tube lengths were measured. Error bars, SD of triplicates samples. Similar results were observed in three independent experiments; *** p < 0.001 versus buffer.