Fig. 7
M2 macrophage polarization by exosomal miR-934 promotes invasion and liver metastasis of CRC cells by activating the CXCL13/CXCR5 axis. a A human chemokine screening test kit was applied to analyze the levels of chemokines involved in M2 macrophage polarization in PMA-pretreated THP-1 cells treated with HCT-8 cell-derived exosomes. b The effect of exogenous miR-934 on the expression of CXCL13 in PMA-treated THP-1 cells was determined using ELISA. c ELISAs were used to determine the expression of CXCL13 in PMA-treated THP-1 cells cocultured with exosomes derived from HCT-8 and HT-29 cells, which were transfected with miR-934 mimics or anti-miR-934. d Representative IHC staining of CXCR5 in CRC tissues and paired normal tissues. e–i PMA-treated THP-1 cells were cotransfected with miR-934 mimics and anti-CXCL13 antibody, and then the CM were obtained and cocultured with SW480 or RKO cells for 12 h. SW480/RKO cells were transfected with shCXCR5 and negative control vectors; we obtained CM from PMA-treated THP-1 cells cotransfected with miR-934 mimics and cocultured CXCR5 knockdown or control SW480 or RKO cells with the CM for 12 h. Migration and invasion in vitro (e, f) and liver metastasis in vivo (g–i) were evaluated using a transwell assay and live imaging combined with HE staining, respectively (*p < 0.05; **p < 0.01; ***p < 0.001)