The increased sensitivity of 4T1-conditioned macrophages to LPS is dependent on actin polymerization.

<p>(A) BMDMs were pre-treated for 1 h with the indicated concentrations of AG490, BAY 11–7082, cytochalasin D, GW2580, JNK inhibitor II, nocodazole, PD184352, SB203580, wortmannin, or the DMSO vehicle prior to a 24 h treatment with 4T1- or HC11-conditioned medium (CM). (B) BMDMs were transfected with IRF-1 or control siRNA for 24 h prior to a 24 h treatment with 4T1- or HC11-CM. BMDMs were then washed with PBS and stimulated with 100 ng/ml LPS for 4 h. Culture supernatants were collected and assessed for the levels of IL-6 by ELISA. Results are shown as the mean (± SEM) IL-6 levels of at least 4 independent experiments. Statistical analyses were done by ANOVA, followed by Tukey’s multiple comparison tests; * p < 0.05.