Fig. 4

miR-HER2-E1 delivered to HER2-positive cancer cells via exosomes reduces cell viability by activation of caspase-3/7. a Effects of exosome-delivered miR-HER2-E1 on the viability of HER2-positive (+) cancer cells (SK-OV-3 and HCT116) and HER2-negative (−) cells (HEp-2 and MDA-MB-231) measured by the CCK8 assay. Results are expressed as the mean of the cell viability index ± standard deviation compared to the mock-treated control (as 100%). b Similarly, the activities of caspase-3/7 were assessed by a Caspase‐Glo 3/7 assay kit after 24 h-treatment of exosomes. The caspase-3/7 activity is expressed as fold change compared to the mock treated (Mock) group. Data are presented as mean ± standard error of three independent experiments. Statistically significant differences between miR-HER2-E1 exosomes and the mock-treated are indicated by an asterisk (**p < 0.01; ***p < 0.001) in the HER2-positive (+) group. N.S. indicates no significant difference