Figure 3.

Characterization of tumor-associated blood vessels and hematogenous metastasis in 231^Luc+ tumors implanted in SS.BN3^IL2Rγ and SS^IL2Rγ rats at 24 days post-implantation. (A) Visualization of tumor-associated blood vessels at using anti-CD31 staining of 231^Luc+ tumors implanted in SS.BN3^IL2Rγ and SS^IL2Rγ rats. Images were acquired at 100X magnification. Scale bar represents 100 μm. (B) Mean blood vessel density in 231^Luc+ tumors implanted in SS.BN3^IL2Rγ and SS^IL2Rγ was calculated from three images per tumor (n= 5–6 tumors per strain) acquired at 100X magnification. Data are presented as the mean vascular density per 100X field ± SEM. *P<0.05 as determined by Student unpaired t test.(C) Percentage of open lumens in 231^Luc+ tumors implanted in SS.BN3^IL2Rγ and SS^IL2Rγ was calculated from three images per tumor (n= 5–6 per strain) acquired at 100X magnification. Data are presented as the percentage of CD31⁺ vessels with open lumens per 100X field ± SEM. *P<0.05 as determined by Student unpaired t test. (D) Percentage of CD31⁺ vessels invaded by 231^Luc+ cells in tumors implanted in SS.BN3^IL2Rγ and SS^IL2Rγ was calculated from three images per tumor (n= 5–6 tumors per strain) acquired at 100X magnification. Data are presented as the percentage of CD31⁺ vessels with open lumens per 100X field ± SEM. ***P<0.001 as determined by Student unpaired t test. (E) Representative luminescent imaging of lungs from tumor-bearing SS^IL2Rγ and SS.BN3^IL2Rγ rats. (F) Hematogenous metastatic burden in was measured by luciferase activity normalized to total milligrams of protein in lung lysates from SS^IL2Rγ (n = 12) and SS.BN3^IL2Rγ (n = 16) rats. Metastatic burden of individual rats are represented by the dots and the black bars indicate the average metastatic burden per strain. *P<0.05 as determined by Student unpaired t test.