Fig. 4

Functional studies of E/M-exosomes in A549 cells a Immunofluorescence microscopy revealed that green PKH67-labeled exosomes were readily taken up and incorporated into cultured A549, as shown by DAPI staining. Obvious green fluorescence signal appeared around the blue fluorescence stained nuclei of A549. b Morphological cellular changes of epithelial A549 cells upon M-exosome delivery. c The migrated cell numbers were significantly different between four groups with different treatments. d Matrigel invasion assays demonstrated the same trend. e E/M-exosomes induce an increase of N-cadherin and vimentin protein levels in A549 cells. Upregulated expression became more pronounced after co-culture with M-exosomes than with E-exosomes. However, no effects of exosomes could be found on E-cadherin expression. f mRNA level of N-cadherin and vimentin was only significantly upregulated after M-exosome stimulation, indicating M-exosomes showed stronger influence than E-exosomes. (*P < 0.05, **P < 0.01)