Fig. 7

Tumor cells-secreted miR-301a-3p induced vascular leakiness and promoted tumor metastasis in vivo. a Increased fluorescence intensity of FITC-dextran was observed following exposure of HUVECs to EVs-miR or EVs-con for 1 h. Data are shown as mean ± SD (n = 3). b Effects of EVs-miR or EVs-con on tube formation ability of HUVECs by tube formation assay. Scale bar = 100 µm. Data are shown as mean ± SD (n = 3). c Effects of EVs-miR or EVs-con on vascular outgrowth of aortic rings which was quantified by counting all sprouts from one ring. Scale bar = 20 µm. Data are shown as mean ± SD (n = 3). d Mice were injected with EVs-miR or EVs-con for a total of ten treatments, and then the appearance of injected FITC-dextran was examined in lung. Scale bars = 50 μm. Nuclei, Blue (DAPI); FITC-dextran, Green. e Immunohistochemical staining for CD31, ZO-1, was applied to evaluate the extent of vascular damage caused by EVs-miR or EVs-con treatment. Scale bars = 50 μm. Nuclei, Blue (DAPI); CD31, Green; ZO-1, Red. f Schematic illustration of the establishment and experimental protocol for tail vein metastasis assay. g Representative hematoxylin/eosin (HE) images of lung sections of mice pre-treated with EVs-miR or EVs-con. Scale bars = 500 µm. Statistical analysis in a–c was measured by one-way ANOVA