Figure 4

CXCR7 enhances recruitment of M2 macrophages into tumor stroma. Tumors from mice used in experiment presented in Figure 2 were subjected to IHC (20×) staining for macrophage marker, F4/80. (A) Representative image of 4T1 Vec and 4T1 sh-CXCR7 (B) 4T1.2 tumors treated with either DMSO or CXCR7 inhibitor (CCX771) or STAT3 inhibitor (S31-201). The F4/80⁺-stained cells were counted in four different fields by using bright-field microscope in each experimental group, and the average was calculated. Bars represent the mean ± SD of number of F4/80 macrophages (C) 4T1 Vec, 4T1 sh-CXCR7 and (D) 4T1.2 tumors treated with either DMSO or CXCR7 inhibitor (CCX771) or STAT3 inhibitor (S31-201). CD11b⁺F4/80⁺CD206⁺ cells in tumors were quantified by flow cytometry (E, F) 4T1 and 4T1 sh-CXCR7 (G, H) 4T1.2 tumors treated with either DMSO or CXCR7 inhibitor (CCX771) or STAT3 inhibitor (S31-201). Lungs were removed and stained for Arginase-1 (5X) (I) 4T1 Vec or 4T1 sh-CXCR7 (insets: 40× magnification) and (J) 4T1.2 tumors treated with either DMSO or CXCR7 inhibitor (CCX771) or STAT3 inhibitor (S31-201) (2.5×; insets, 10× magnification). Data represent the mean ± SD per experimental group. Scale bars, 0.03 mm. *P < 0.05, ^**P < 0.01 versus vehicle or vector control.