Exosomal delivery of miR-200b-3p suppresses the growth of hepatocellular carcinoma cells by targeting ERG- and VEGF-mediated angiogenesis.

Hepatocellular carcinoma (HCC) remains a lethal malignancy with limited treatment options. Recent discoveries have highlighted the pivotal role of miRNAs in HCC progression. We previously reported that the expression of miR-200b-3p was decreased in HCC cells and exosomal miR-200b-3p from hepatocytes inhibited angiogenesis by suppressing the expression of the endothelial transcription factor ERG (erythroblast transformation-specific (ETS)-related gene), leading to the hypothesis that the delivery of this miRNA may inhibit angiogenesis and suppress HCC growth in vivo. Here, we tested this hypothesis by using human HCC inoculation models. First, we transfected the human HepG2 HCC cells and established a stable cell line that overexpressed a high level of miR-200b-3p. When miR-200b-3p-overexpressing cells were injected into severe combined immunedeficiency (SCID)-beige mice, tumor growth was significantly reduced compared to tumors of control cells, with a reduction in the expression of ERG and vascular endothelial growth factor (VEGF) and subsequent angiogenesis. Intra-tumoral injection of exosomes containing high levels of miR-200b-3p also reduced the growth of parental HepG2 tumors with reduced ERG and VEGF expression and angiogenesis. These results validate the inhibitory role of miR-200b-3p in tumor angiogenesis, thereby suppressing HCC tumor growth, and provide a novel insight into its potential therapeutic application.