Fig. 3. Hepatocellular carcinoma (HCC)-derived exosomal miR-451a inhibits endothelial cell apoptosis. A, Exosomal miR-451a delivery from SMMC-7721 cells to human umbilical vein endothelial cells (HUVECs). Top: SMMC-7721 cells transfected with miR-451a-Cy3 mimics, and cultured in the presence or absence of exosome secretion inhibitor GW4869. Bottom: HUVECs incubated with SMMC-7721 exosomes. B, Exosomes were derived from SMMC-7721 cells transfected with miR-451a mimics in the presence or absence of GW4869, and were co-cultured with HUVECs. Cell viability was examined by CCK8 assays. C-E, Different concentrations of miR-451a mimics were transfected into HUVECs. Cell viability was measured by CCK8 assays (C). Apoptosis was measured by Annexin V (D) and TUNEL (E) assays. PI, propidium iodide; NC, negative control; *P<0.05, **P<0.01, ***P<0.001.