Fig. 1

Tumor cell-derived exosomes promote tumor invasion via an increase in endothelial monolayer permeability. a Scanning electron microscope was used to examine exosome’s morphology and size. b The expression of CD63, in the culture medium of Hs 766 T or Hs 766 T-L2 cells by WB. c Exosomes were labeled with DiI dye and co-cultured with Calcein AM-labeled HUVECs for 24 h. Red fluorescent spots were observed in the cytoplasm of HUVECs. Scale bars = 100 μm. d HUVECs were seeded and cultured on cell slides and then transfected with exosomes extracted from Hs 766 T or Hs 766 T-L2 cells or PBS as a control. F-actin was labeled with TRITC-conjugated Phalloidin, and focal adhesion sites were labeled with fluorescein isothiocyanate (FITC). The slides were examined by confocal microscopy followed by fluorescence microscopy. Scale bars = 100 μm. e WB, which was used to evaluated the expression of F-actin, showed the same results as IF. f HUVECs were cultured in a 24-well Transwell upper chamber for 2 days to construct an endothelial monolayer model. g Tumor cells that passed through the endothelial monolayer and attached to the lower side of the filter were imaged by microscopy (Olympus) and counted. Scale bars = 50 μm