Exosomal miR-138-5p regulates macrophage polarization via inhibiting KDM6B expression. (A) RT-qPCR analysis of M1- and M2-associated genes, (B) western blot analysis of CD163 and TNF-α expression, and (C) Flow cytometry of CD163-positive cells in KDM6B-overexpressing THP-1 cells cocultured with MDA-MB-231 cells for 48 h. THP-1 cells overexpressing miR-138-5p or NC were transfected with the KDM6B expression plasmid or control for 48 h. (D) RT-qPCR analysis of M1- and M2-associated genes expressed in THP-1 cells. (E) Western blot analysis of CD163 and TNF-α expression in THP-1 cells. (F) Flow cytometric analysis of CD163-positive cells. (G) RT-qPCR analysis of M1- and M2-associated genes, (H) western blot analysis of CD163 and TNF-α expression, and (I) CD163-positive cells in THP-1 cells incubated with PBS or with exosomes derived from T47D cells transfected with NC or miR-138-5p mimics. (J) RT-qPCR analysis of M1- and M2-associated gene expression, (K) western blot analysis of CD163 and TNF-α expression and (L) flow cytometric analysis of CD163-positive cells in THP-1 cells. THP-1 cells transfected with NC or an miR-138-5p inhibitor were treated with PBS or exosomes from MDA-MB-231 cells for 48 h. The results are shown as the mean ± SEM of three independent experiments. *P < 0.05; **P < 0.01; ***P < 0.001.