Rosiglitazone antagonizes macrophage cytokine secretion induced by conditioned media derived from MCF7 and MDA-MB-231 breast cancer cells. (a) Immunoblotting of PPARγ in M0 macrophages (-) incubated with CM MCF7 or CM MDA for 72 h. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as loading control. The blot is representative of three independent experiments, while the numbers below the blots represent the average fold change between PPARγ and GAPDH protein expression with respect to M0 macrophages. (b) Immunoblotting of STAT3 in M0 macrophages incubated with CM MCF7 or CM MDA and treated with rosiglitazone (BRL) 10 μM alone or in combination with GW9662 (GW) 10 μM for 72 h. GAPDH or β-actin was used as the loading control. Each blot is representative of three independent experiments, while the numbers below the blots represent the average fold change between STAT3 and GAPDH or β-actin protein expression with respect to vehicle-treated cells. ELISA analyses of IL6 (c) and IL1Ra (d) proteins in M0 macrophages incubated with CM MCF7 or CM MDA, and treated with BRL 10 μM alone or in combination with GW 10 μM for 72 h. Data are expressed as means ± SDs of three independent experiments, each performed with duplicate samples. The results are expressed as fold changes with respect to vehicle-treated cells (-). * p < 0.05, ** p < 0.005, *** p < 0.0005, **** p < 0.0001, ns = not significant.