Fig. 2

Loss of TAp73 increases tumor blood vessel permeability through reduced endothelial cell?cell contact. (A and B) TAp73^+/+ and TAp73^?/? tumors perfused with FITC-labeled dextran and stained for endothelial cells (endomucin). Green, FITC-labeled dextran leakage into the extravascular tumor space; red, endomucin staining of blood vessels. Mean fluorescent intensity (MFI) was determined for total dextran-FITC (green) signal with pixel counting; intravascular dextran-FITC (yellow) was subtracted from the final value (n = 5/group, five fields/tumor was used for quantification; ****P < 0.0001). (Scale bar, 100 ?m.) (C) Schematic representation of in vitro cell permeability assay. (D) SEM of confluent monolayer HuDMECs treated with CM from hypoxic TAp73^+/+ or TAp73^?/?MEFs^E1A/Ras (Middle and Bottom) or control HuDMEC media (Top). (Top and Middle) Arrow indicating well-defined junctions and cell?cell contact. (Bottom) Breaks in cell?cell contact and gaps between HuDMECs treated with CM from hypoxic TAp73^?/?MEFs^E1A/Ras. (Scale bar, 10 ?m.) (E and F) VE?cadherin (red) immunofluorescence staining and quantification. (Scale bar, 50 ?m.) (Top and Middle) HuDMECs treated with control media or CM from hypoxic TAp73^+/+ MEFs^E1A/Ras present distinct interendothelial VE-cadherin bonds and close cell?cell contact. (Bottom) Interendothelial VE-cadherin bonds are lost, resulting in weakened cell?cell contact in HuDMECs treated with CM from hypoxic TAp73^?/? MEFs^E1A/Ras.