Fig. 4

Exosomal miR-9 derived from NPC cells targeted MDK in endothelial cells. a Seventeen angiogenesis-related factors were overlapped predicted by Targetscan, miRBase and Pictar. b The mRNA level of MDK in HUVEC cells after miR-9-overexpressing exosomes treatment. c Diagram of MDK 3′UTR-containing reporter constructs. d Luciferase reporter assays in HUVECs, with cotransfection of wt or mt MDK 3′UTR and exosomes derived from 5-8F/con or 5-8F/miR-9 cells as indicated. These experiments were performed in triplicate, and the results were shown as Mean ± SD. e Luciferase reporter assays in HUVECs, with cotransfection of wt or mt MDK 3′UTR and exosomes derived from CNE1/con or CNE1/miR-9 cells as indicated. f The protein levels of MDK in HUVEC cells after treatment with different exosomes as indicated. The intensity of each band was normalized by GAPDH. g The protein levels of MDK in NPC cells after transfection with miR-9 mimic or negative control. h After direct knockdown of MDK in HUVEC cells by siRNA, cell migration was measured and quantified by Transwell migration assay. i After direct knockdown of MDK in HUVEC cells by siRNA, tube formation of HUVECs was examined by in vitro tube formation assay and quantified for tubule length. **, P < 0.01