Fig. 5.

Tumor characterization. A) Immunoblotting of U-87MG and A431 tumor extracts. A calibration curve of human purified integrin β₃ subunit was used to assess the protein content in the tumors, β-actin was used as loading control. The graph shows the amount of β₃ normalized to the tumor weight for U-87MG and A431 tumor (n = 4). B) Immunofluorescence staining of the endothelial marker CD105 on U-87MG and A431 tumor cryosections. The graph shows the percentage of area covered by CD105-positive vessels relative to the whole tumor area (n = 4). Scale bar: 500 μm. **P < 0.0001, unpaired, two-tailed Student’s t-test. C) Fluorescence distribution of ICG and ICG-RGD in U-87MG tumor cryosections. A high fluorescence signal was detected in tumors from animals injected with ICG-RGD (right), while only low signal was visible after ICG administration (left).