Impacts of A549 exosomes on cell proliferation and apoptosis in HLF1 cells and A549 cells. In HLF1 cells, cell proliferation was promoted (A), cell apoptosis rate declined (B, D), Caspase 3 level did not vary (C), C-Caspase 3 expression was decreased, and Bcl-2 expression was increased in Exosome group compared with NC group. In A549 cells, cell proliferation increased in Exosome group compared with NC group (E), while cell apoptosis rate was decreased (F, H), C-Caspase 3 level was declined (G) and Bcl-2 level was increased in Exosome group than that in NC group. Comparison between two groups was determined by t test. P<0.05 was considered significant. *P<0.05, **P<0.01. NC, negative control.