Fig. 6

Inhibition of CXCR2 decreases infiltration of suppressive neutrophils in the tumor microenvironment. a, Lung tissues of mice from orthotopic lung cancer model treated with vehicle or SB225002 (10 mg/kg) were collected and digested for flow cytometric analyses of infiltrated neutrophils (CD45⁺CD11b⁺Ly6C^midLy6G^high) and monocytes (CD45⁺CD11b⁺Ly6C⁺Ly6G⁻) in tumor microenvironment. Data was shown as mean ± SD, n = 6–7. b-c, Neutrophils (CD45⁺CD11b⁺Ly6C^midLy6G^high) from tumor microenvironment (TAN), peripheral blood of tumor-bearing mice (tPBN), and peripheral blood of normal mice (nPBN) were further analyzed. TGF-β (b) and TNF-α (c) produced by neutrophils of three groups were determined by flow cytometry. Data was shown as mean ± SD, n = 6–7. d, Expression of CXCR2 on the surface of nPBN and tPBN. Data was shown as mean ± SEM from three parallel experiments, n = 3. e, Primary neutrophils were extracted from the bone marrow of healthy mice, and then seeded in plates and treated by tumor supernatant (TS) or RPIM 1640 medium. Expression of CXCR2 on the surface of neutrophils was detected by flow cytometry. Data was shown as mean ± SEM from three parallel experiments, n = 3. f, 1 × 10^6 primary neutrophils were seeded into the upper chamber (3 μM), and RPIM 1640 medium, LL2 cell tumor supernatant, chemokine CXCL2 (50 ng/ml), or SB225002 (500 nM) were added into the bottom chamber (left)). After 6 h of incubation, the number of migrated neutrophils was counted by flow cytometry (right). Data was shown as mean ± SEM from three parallel experiments, n = 3. *p < 0.05, **p < 0.01, ***p < 0.001, ns represents p>0.05