Fig. 5: Monocyte-derived IL-1 promotes the CRC EGC phenotype.

a, b Primary embryonic neurosphere-derived EGCs were stimulated for 24 h with IgG or anti-IL-1R (5 µg/mL each) with or without the supernatant of sorted tumor monocytes or bone marrow (BM)-derived monocytes from WT C57BL/6J mice bearing orthotopic CRC tumors. Schematic representation of experimental setup (a). Relative mRNA levels of Lcn2, Timp1, Ccl2, and Il6, normalized to the housekeeping gene Rpl32, in primary embryonic neurosphere-derived EGCs were compared between EGCs stimulated with tumor monocyte supernatant + IgG and all other conditions (n = 3 primary EGC cultures and monocytes) (b). c–g CCR2^+/+ and CCR2^−/− mice were intracolonically injected at day(d)0 with MC38 cells, tumor tissue was collected at d21. Then, in vitro embryonic neurosphere-derived EGCs were cultured for 24 h with the tumor microenvironment-conditioned medium (TME-CM) of CCR2^+/+ and CCR2^−/− tumors. Schematic representation of experimental setup (c). Representative pictures (left, scale bar 2 mm) and quantitative comparison of tumor volume (right) (n = 16 CCR2^+/+, n = 17 CCR2^−/−) (d). Representative contour plots of tumor-infiltrating monocytes and macrophages gated on live-CD45⁺-CD11b⁺-Ly6G⁻-CD64⁺ cells (e). Relative mRNA levels of Il1b and Il1a normalized to the housekeeping gene Rpl32 in CCR2^+/+ and CCR2^−/− CRC tumors (n = 3 mice) (f). Relative mRNA levels of Lcn2, Timp1, Ccl2, and Il6 in EGCs stimulated with TME-CM of CCR2^+/+ and CCR2^−/− mice, normalized to the housekeeping gene Rpl32 (n = 3 TME-CM) (g). Data represented as mean ± SEM (b, d, f, g). Statistical analysis: One-way ANOVA test with correction for multiple comparisons, compared to tumor monocyte supernatant + IgG condition (b), unpaired two-tailed Mann Whitney test (d) or unpaired two-tailed t-test (f, g). *p < 0.05, **p < 0.005, ***p < 0.0005, ns not significant. Source data and exact p values are provided as a Source Data file.