Fig. 4

CD11b⁺Ly6C^midLy6G^hiCXCR2⁺ neutrophils significantly infiltrate into tumor tissue of LL2-bearing mice. a, Construction of lung orthotopic model and subcutaneous tumor model in mice, n = 6–7. For lung orthotopic model, 5 × 10^5 LL2 cells were injected into tail vein of C57BL/6 mice. For subcutaneous tumor model, 2 × 10^6 LL2 cells were injected into the right flank of C57BL/6 mice. At the endpoint of experiments, lung tumor nodules and tumor masses were collected for further analyses. b, Flow cytometric characterization of neutrophils (CD45⁺CD11b⁺Ly6C^midLy6G^highCXCR2⁺) and monocytes (CD45⁺CD11b⁺Ly6C^highLy6G⁻) from tumor tissues. CXCR2-unstained cells were used for negative control. c, Flow cytometric analyses of neutrophils and monocytes infiltrated in the tumor microenvironment of normal and tumor-bearing mice (left) and quantification of infiltrated immune cells (right). Data was shown as mean ± SEM, n = 6–7. d, The relative mRNA expression of CXCL1, CXCL2, CXCL5, and MIF in the lung of normal and tumor-bearing mice. Data was shown as mean ± SEM, n = 6–7. e, Immunohistochemistry staining of neutrophils’ markers CXCR2 and Ly6G, and immune suppressive markers TGF-β and Arg-1 in the lung of normal and tumor-bearing mice. Scale bar, 50 μm. *p < 0.05, **p < 0.01, ***p < 0.001, ns represents p>0.05