Figure 4

Opposing roles of CXCR4 and CXCR7 in primary tumor growth, intravasation and lung metastasis formation. (a) Primary tumor volumes at 30 to 34 days post orthotopic injection of MTLn3 JP (21 mice), MTLn3 CXCR4 (20 mice), MTLn3 CXCR7 (19 mice), and MTLn3 CXCR4-CXCR7 (29 mice). MTLn3 JP vs. MTLn3 CXCR7 (a) P < 0.05; MTLn3 JP vs. MTLn3 CXCR4-CXCR7 (b) P < 0.05; MTLn3 CXCR4 vs. MTLn3 CXCR4-CXCR7 (c) P < 0.05 with P values determined using Mann Whitney. (b) CXCR7 overexpression increases angiogenesis of MTLn3 tumors. MTLn3 JP, MTLn3 CXCR4, MTLn3 CXCR7, and MTLn3 CXCR4-CXCR7 primary tumors were harvested when they reached an average volume of 1,100 mm³, fixed and paraffin embedded. Immunohistochemistry to stain blood vessels was done using an antimouse CD34 antibody. Three tumors were used per cell line, with five fields counted per tumor. Representative images are shown (top), scale bar 100 μm, with the respective quantitation of mean vessel density (MVD, bottom). Student's t-test was used for two-condition comparisons and confirmed with ANOVA; MTLn3 JP vs. MTLn3 CXCR7 (a) P < 0.005; MTLn3 JP vs. MTLn3 CXCR4-CXCR7 (b) P < 0.05; MTLn3 CXCR4 vs. MTLn3 CXCR4-CXCR7 (c) P < 0.005. VEGFA immunohistochemistry of MTLn3 JP, MTLn3 CXCR4, MTLn3 CXCR7, and MTLn3 CXCR4-CXCR7 primary tumors. Three tumors were used per cell line with one representative tumor being shown, scale bar 200 μm. Staining in all samples is significantly greater than that seen with control staining with a nonspecific primary antibody (data not shown). Scale bar: 200 μm. (d) Intravasation of the different MTLn3 transductants measured using a blood burden assay. The total number of cancer cell colonies present were counted and normalized to the total volume of blood collected. MTLn3 JP n = 21 mice, MTLn3 CXCR4 n = 20 mice, MTLn3 CXCR7 n = 10 mice, MTLn3 CXCR4-CXCR7 n = 17 mice. MTLn3 JP vs. MTLn3 CXCR4 (a) P < 0.05; MTLn3 CXCR4 vs. MTLn3 CXCR4-CXCR7 (b) P < 0.005 with P values determined using Mann-Whitney. (e) Spontaneous lung metastasis formation of the MTLn3 transductants. The different cell lines were injected into the mammary fat pad and lungs harvested once the primary tumors reached an average volume of 1,500 mm³. MTLn3 JP n = 19 mice, MTLn3 CXCR4 n = 20 mice, MTLn3 CXCR7 n = 16 mice, MTLn3 CXCR4-CXCR7 n = 29 mice. The total number of lung metastases present in all lung lobes of a single H&E section are reported. MTLn3 JP vs. MTLn3 CXCR7 (a) P < 0.005; MTLn3 JP vs. MTLn3 CXCR4-CXCR7 (b) P < 0.005; MTLn3 CXCR4 vs. MTLn3 CXCR4-CXCR7 (c) P < 0.005. Means and SEMs are shown.