Fig. 5

Exo-miR-519a-3p induces M2-like polarization of macrophages to promote agiogenesis and facilitate liver metastasis. A, B. PMA-treated THP-1 cells were incubated with exosomes from miR-519a-3p overexpressing MKN45 cells or miR-519a-3p knockdown MKN45-HL cells. The expression levels of CD163, IL-10, TGFB1, VEGFA, iNOS, and TNFA were subsequently measured by qRT-PCR. C. PMA-treated THP-1 cells were incubated with GC cell-derived exosomes with knockdown or overexpression of miR-519a-3p. The percentage of CD206-positive THP-1 cells were then measured by flow cytometry. D. The effect of exo-miR-519a-3p on the secretion of TGF-β, VEGFA, and VEGFD in PMA-treated THP-1 cells was determined by ELISA. E. Transwell assays of HUVECs were performed after 48 h of incubation with conditioned medium from PMA-treated THP-1 cells pre-incubated with miR-519a-3p-knockdown/overexpressed exosomes. Scale bar = 200 μm. F. Tubule formation assays of HUVECs were performed after incubation with conditioned medium from PMA-treated THP-1 cells. Scale bar = 200 μm. G. Effect of conditioned medium from PMA-treated THP-1 cells on vascular outgrowth of mouse aortic rings. Scale bar = 500 μm. H. Mice were educated with miR-519a-3p-inhibited/expressed exosomes from GC cells and then injected with luciferase-labeled MKN45 cells into the spleen. Liver metastasis was assessed 3 weeks later with IVIS. I, J. Mice from each of the above groups were sacrificed after completion of IVIS, and livers were collected for photographs and H&E staining. Scale bar = 500 μm. Data are shown as mean ± standard deviation of 3 independent experiments, and statistical significance was determined using Student’s t test and one-way ANOVA test (*P < 0.05, **P < 0.01, ***P < 0.001)