Fig. 1.

Extracellular vesicles (EV) secreted by hypoxia pre-challenged mesenchymal stem cells (MSCs) promote A549 and H23 cell proliferation, survival, mobility and EMT in vitro. Cells were pre-treated with EVs secreted by naïve (N-EV) or hypoxia pre-challenged (H-EV) MSCs. a and b, CCK-8 cell proliferations assay evaluating viable cell count at different timepoints. c–g, A549 and H23 cell apoptosis under normal, hypoxia challenge (1% O₂) or cisplatin challenge (5 μM) after N-EV or H-EV treatment. Hypoxia or cisplatin challenge was performed for 24 h before analysis. h–i, trans-well assay evaluating A549 and H23 cells invasion after N-EV or H-EV treatment. A549 or H23 cells treated with PBS vehicle were used as negative control (NC). Bar in I indicates 20 μm. j–l, western blot detecting epithelial and mesenchymal marker in A549 and H23 cells after treatment with N-EV or H-EV. Statistical analysis results by Student’s t test was marked by # and that by Dunnett’s test were marked by *. * or #, p < 0.05; ** or ##, p < 0.01; ***, p < 0.001