Fig. 2: CSF1 secreted by MDA-MB-231 cells induces CXCL7 expression from THP-1 monocytes.

A CXCL7 mRNA expression in the presence of recombinant CSF1. THP-1 or U937 cells were treated with recombinant CSF1 (10 or 30 ng/mL) for 48 h, RNA was then extracted to detect CXCL7 expression. Data represent the normalized means ± SD (n = 3 biological replicates; *p < 0.05; **p < 0.01). B CSF1 mRNA expression in MDA-MB-231, THP-1, U937 cells, or MDA-MB-231 cells co-cultured with THP-1 or U937 monocytes for 48 h. RNA was extracted from MDA-MB-231, THP-1, or U937 cells for analysis as indicated. Data represent the normalized means ± SD (n = 3 biological replicates; **p < 0.01). C The CSF1 protein concentration collected from the cultured media of MDA-MB-231, THP-1, U937 cells only or MDA-MB-231 co-cultured with THP-1 or U937 cells for 48 h were determined by ELISA assay. Data represent the means ± SD (n = 3 biological replicates; *p < 0.05; ***p < 0.001; ****p < 0.0001). D CXCL7 mRNA expression in THP-1 cells co-cultured with MDA-MB-231 cells in the presence of CSF1 neutralizing antibodies (5 μg/ml) or equivalent amount of control IgG for 48 h, RNA was extracted to detect CXCL7 expression. The level of CXCL7 mRNA in MDA-MB-231 cells co-cultured with THP-1 monocytes was used as a control. Data represent the normalized means ± SD (n = 3 biological replicates; **p < 0.01; ***p < 0.001; ****p < 0.0001).