Tumor-Derived CXCL1 Promotes Lung Cancer Growth via Recruitment of Tumor-Associated Neutrophils

Figure 3

Knockdown of CXCL1 expression in 3LL cells decreases the number of neutrophils in vivo. 5 × 10⁵ 3LL/NC or 3LL/shCXCL1 cells were inoculated subcutaneously (s.c.) into C57BL/6J mice. At day 16, mice were scarified. The CD11b⁺Ly6G⁺ neutrophils in peripheral blood were detected as described in the materials and methods. Representative flow cytometric graph (a) and percentage of CD11b⁺Ly6G⁺ neutrophils in peripheral blood (b) were analyzed. Each dot plot represents an individual mice; horizontal lines are shown as mean of each group. (c) Flow cytometric analysis of the frequency of CD11b⁺Ly6G⁺ neutrophils in bone marrow from mice inoculated with 3LL/NC or 3LL/shCXCL1. (d) Flow cytometric analysis of the frequency of CD11b⁺Ly6G⁺ neutrophils in spleen from mice inoculated with 3LL/NC or 3LL/shCXCL1 tumor cells. (e, f, g, and h) IHC staining of Ly6G⁺ or MPO⁺ cells in the tumor tissues from mice inoculated with 3LL/NC or 3LL/shCXCL1 tumor cells. IHC staining quantification of Ly6G⁺ (f) or MPO⁺ (h) cells (per high-power field, HPF). Scale bars, 20 μm or 40 μm. (i) Neutrophils were isolated from spleen or peripheral blood derived from tumor-bearing mice and the chemoattracted CD11b⁺Ly6G⁺ neutrophils were analyzed towards the condition supernatant from NC and shCXCL1 tumor cells by in vitro transwell assay. , .

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