Fig. 3

Secreted miR-9 derived from glioma cells enhances angiogenesis in HUVECs. a The HUVECs were cultured alone or co-cultured with A172, U87 and U251 cells, respectively. The expression of miR-9 in HUVECs was detected via qRT-PCR after co-culture. Data are presented as the mean ± s.d. (*P < 0.05, **P < 0.01 and ***P < 0.001; n = 3 independent experiments). b HUVECs were cultured with the conditional medium from A172 miR-9 mimic/NC and U251 miR-9 inhibitor/NC cells, and the amount of capillary-like tubes was determined after 48 h. Photos were taken and the tubes were counted under a microscope at the indicated time. Scale bars represent 200 μm. Data are represented as the mean ± s.d. (**P < 0.01 and ***P < 0.001; n = 3 independent experiments). c Expression level of VEGF in the cell lysates of the A172 miR-9 mimic/NC and U251 miR-9 inhibitor/NC cells were analyzed by ELISA assays. Error bars represent the s.d. (*P < 0.05; n = 3 independent experiments). d The HUVECs cultured via the conditional medium from A172 miR-9-FAM and U251 miR-9-FAM cells were observed by a fluorescence microscope. Scale bars represent 100 μm. e The A172 and U251 exosomes were observed and taken photos under a transmission electron microscope. Exosomes are marked by the white arrows. Scale bars represent 200 nm. f MiR-9 levels within the A172 and U251 exosomes were assessed by qRT-PCR analysis. Data are shown as the mean ± s.d. (***P < 0.001; n = 3 independent experiments). g and h Capillary-like tubes from the U251 exosomes or control treated HUVECs were taken photos (g) and counted (h) under a microscope. Scale bars represent 500 μm. Data are represented as the mean ± s.d. (**P < 0.01; n = 3 independent experiments)