Fig. 9: Therapeutic targeting of IL-9-macrophage axis prevents lung cancer growth.

a Kaplan–Meier plots showing differences in survival among lung cancer patients (n = 982 donors) by using data and online tools described in Methods for ARG1 and IL6. b Comparison of gene expression in normal lung tissue and metastatic lung tissues by using data and online tool described in the method. The bars represent the proportions of metastatic tumor samples that show higher expression of the selected gene compared to normal samples at each of the quantile cutoff values (minimum, 1st quartile, median, 3rd quartile, maximum). c IL9R and IL6 gene expression were analyzed in cells from normal lung tissue and cells in the lung tumor (n = 8 donors for non-tumor group and n = 9 donors for lung cancer group in left panel, n = 6 donors for non-tumor group and n = 4 donors for lung cancer group in right panel). d Serum IL-9 level, IL-6 level and arginase activity were analyzed from healthy donors and lung cancer patient samples. (n = 5 donors for left panel, n = 7 donors for non-tumor group and n = 4 donors for lung cancer group in middle panel, n = 7 donors for non-tumor group and n = 5 donors for lung cancer group in right panel). e Dot plot showing gene expression in macrophages between normal lung tissue and lung tumor. f, g Immunohistochemistry staining of CD68 and IL-9R. Protein expression quantification was performed by using Image J software (n = 7 donors), Scale bar = 100 µm. h–l WT mice were intravenously injected with B16 tumor cell line, 7 days after tumor inoculation, tumor bearing mice were intravenously injected with nanoparticle-siRNA complexes every 72 h. Scr/Il9r-siRNA was conjugated with Alexa Flour 555. Nanoparticles were tagged with SIRPα peptide (h). i Lung tumor growth were analyzed on day 21 (n = 6 mice for Scr-siRNA group, n = 7 mice for Il9r-siRNA group). j IL-9R expression in siRNA⁺ (Alexa Flour 555) lung macrophages were analyzed by flow (n = 6 mice for Scr-siRNA group, n = 7 mice for Il9r-siRNA group). k Arg1 production from siRNA⁺ (Alexa Flour 555) macrophages were analyzed by flow (n = 6 mice for Scr-siRNA group, n = 7 mice for Il9r-siRNA group). l siRNA⁺ (Alexa Flour 555) lung macrophages were sorted by gating on Alexa Flour 555⁺ MerTK⁺ CD64⁺ live cells. Gene expression was analyzed (n = 6 mice for groups in left panel, n = 6 mice for Scr-siRNA group and n = 7 mice for Il9r-siRNA group in right panel). Data are the mean ± SEM. Unpaired two-tailed Student t-test was used for comparison.