Macrophages exposed to 4T1-conditioned culture medium demonstrate increased CCL2 production and promote macrophage recruitment.

<p>(A) Gene expression of monocyte/macrophage chemokines by BMDMs treated for 24 h with 4T1- or HC11-conditioned medium (CM). Expression levels are displayed as the fold change relative to gene expression of BMDMs treated with DMEM alone. (B) CCL2 protein production by BMDMs (Mϕ) treated for 24h with 4T1- or HC11-conditioned medium as measured by ELISA. (C) Macrophage chemotaxis towards the culture supernatants of 4T1- or HC11-conditioned BMDMs (Mϕ). (D) Macrophage chemotaxis towards macrophage culture supernatants pre-treated with 10 μg/ml of a CCL2-neutralizing or an isotype Ab for 1h. Results are shown as the mean (± SEM) of at least 3 independent experiments. Statistical analyses were done by ANOVA, followed by Tukey’s multiple comparison tests; * p < 0.05.