Extended Data Fig. 8: The effect of p38α deficiency specifically in fibroblasts and p38 inhibitors on the primary tumor.

a. Representative flow cytometry analysis of IFNAR1 level in the isolated lung fibroblasts from tamoxifen treated Ifnar1^fl/flCol1a2-CreER^- (Ifnar1^fl/fl) and Ifnar1^fl/flCol1a2-CreER⁺ (Ifnar1^ΔFib, Ifnar1 knock out specific in fibroblasts) mice. Similar results were obtained from three independent experiments. b. qPCR analysis of the indicated chemokines in the lung tissues of Ifnar1^fl/fl (n=7 mice) and Ifnar1^ΔFib mice (n=6 mice) after intravenous injection with 5*10⁵ B16F10-TdTomato cells. Data shown as mean±SEM. Two-way ANOVA and Sidak’s multiple comparisons test were performed. c. Representative flow cytometry analysis of neutrophils in the lung tissues of Ifnar1^fl/fl and Ifnar1^ΔFib mice after intravenous injection with 5*10⁵ B16F10-TdTomato cells. Similar results were obtained from three independent experiments. d. Quantification of the percent (left) and the absolute number of neutrophils (right) in the lung tissues as described in c. Data shown as mean±SEM (n=6 mice for Ifnar1^fl/fl group, n=7 for Ifnar1^ΔFib group). Two-tailed Unpaired t test was performed for the comparison. e. The primary tumor growth of B16F10 in the Mapk14^fl/fl (n=5 mice) and Mapk14^ΔFib (n=8 mice) mice s.c injected with 1×10⁵ B16F10 tumor cells prior to surgery at equivalent tumor size (~200 mm²). f. A representative western blot analysis of p-p38 and total p38 in the WT lung fibroblasts 1 hr after treatment with SFM, or TCM from B16F10 tumor cells pretreated with vehicle (DMSO) or p38 inhibitor LY2228820 (4 μM) for 24 hr. Similar results were obtained from three independent experiments. g. A representative flow cytometry histogram (left) and the quantification of surface IFNAR1 level (right) in WT lung fibroblasts 2 hr after treatment with SFM, or TCM from B16F10 tumor cells pretreated with vehicle (DMSO) or p38 inhibitor LY2228820 (4 μM) for 24 hr. Quantitative data shown as mean±SEM (n=3 biologically independent samples). Two- tailed Unpaired t test was performed for the comparisons between two groups. h. Primary tumor growth of B16F10 in mice that received vehicle, LY2228820 (LY), or SB203580 (SB) treatment prior to surgery at equivalent tumor size (~200 mm²). Data shown as mean±SEM (n=6 mice per group).