Fig. 6: N1 neutrophils and their chemoattractants (CXCL1, CXCL2, and CXCL5) are abundant in the synthetic MNs and endogenous lungs of BALB/c mice with 67NR or 4T07 non-metastatic breast cancer.

a The frequencies of Gr1⁺CD11b⁺Ly6G⁺ neutrophils and the expression of S100a8 and S100a9 genes in healthy tissues of tumor-free BALB/c mice and diseased tissues of mice bearing 67NR or 4T07 non-metastatic or 4T1 metastatic breast cancer tumor. Healthy tissues were the control. b In vivo extravasation of intracardially injected 4T1-Luc2-tdTomato cells to scaffolds and lungs of tumor-free mice and mice bearing non-fluorescent 67NR, 4T07, or 4T1 tumor. c, d The frequencies of IFNγ⁺ and IL-17A⁺ CD4⁺ T cells (c) and immune cells with pro-inflammatory and antitumor phenotypes (d) in diseased scaffolds and lungs of mice bearing 67NR, 4T07, or 4T1 tumors. Diseased tissues from 4T1-bearing mice were the control. e, f The proteins secreted by diseased tissues of mice bearing 67NR (e) or 4T07 (f) tumor compared to those secreted by diseased tissues of mice bearing 4T1 tumor. g The proteins secreted by diseased lungs of mice bearing 67NR, 4T07, or 4T1 tumor compared to those secreted by healthy lungs of tumor-free BALB/c mice. h 4T1-Luc2-tdTomato cells that were transfused to BALB/c mice bearing 67NR tumor through intracardiac injection were attracted to the lungs but failed to grow to a secondary tumor. i In vivo extravasation of intracardially injected N1 neutrophils to scaffolds and lungs of tumor-free BALB/c mice and mice bearing 67NR, 4T07, or 4T1 tumor. Gr1⁺ splenocytes subpopulation migrating towards CXCL1 in the Boyden chamber were isolated, and these neutrophils with verified N1 phenotypes were fluorescently labeled with DiI dye and then transfused into mice by intracardiac injection. Data are shown as Mean ± SEM and p values are from student’s two-tailed t test. n = 3 for (a), (c), (d), n = 6 for (b), (i), and n = 4 for (h). Source data are provided as a Source Data file.