Fig. 4

Blocking CXCR2 significantly restored Arnt^−/−-induced neutrophil recruitment and NET formation in colorectal cancer. A-E Neutrophils induced by GM-CSF from BMs in the presence of anti-CXCR2 for 4 days in vitro. Percentage of CD11b⁺Gr1⁺ neutrophils (A), percentage of NETs in neutrophils (B), intracellular staining of TNFα (C) and IL-10 (D) in neutrophils, suppressive activity assay of neutrophils (E). Representative of three independent experiments. F-N Colorectal cancer induction for 80 days after the injection of azoxymethane (AOM) and the addition of dextran sulfate sodium salt (DSS) to the drinking water and weekly anti-CXCR2 injection. F Typical photos of colorectal cancer. Representative of three independent experiments. G Summary of the number of colonic tumors. The graph summarizes data from three independent experiments with thirteen mice per group. H Summary of tumor diameter. The graph summarizes data from three independent experiments with thirteen mice per group. I Immunohistochemistry analysis of colorectal cancer after staining with anti-Gr1 antibody. Scales bars, 50 μm. Original magnification, 400X. Representative of two independent experiments. J Percent of neutrophils in the colon. K Tumor-infiltrating neutrophils were isolated and stimulated with LPS in vitro as indicated to detect NETs. The percentage of NETs-forming cells was quantified. L-M Intracellular staining of TNFα (L) and IL-10 (M) in neutrophils from the colon. N Suppression assay of tumor-infiltrating neutrophils. The graph summarizes data from three independent experiments with at least four mice per group (J-N). *, P < 0.05; **, P < 0.01 and ***P < 0.001, compared with the indicated groups