Exosome miR-155 Derived from Gastric Carcinoma Promotes Angiogenesis by Targeting the c-MYB/VEGF Axis of Endothelial Cells

Exosomes, membranous nanovesicles, naturally carry proteins, mRNAs, and microRNAs (miRNAs) and play important roles in tumor pathogenesis. Here we showed that gastric cancer (GC) cell-derived exosomes can function as vehicles to deliver miR-155 to promote angiogenesis in GC. In this study, we first detected that the expression of miR-155 and c-MYB was negatively correlated in GC and that c-MYB was a direct target of miR-155. We next characterized the promotional effect of exosome-delivered miR-155 on angiogenesis and tumor growth in GC. We found that miR-155 could inhibit c-MYB but increase vascular endothelial growth factor (VEGF) expression and promote growth, metastasis, and tube formation of vascular cells, causing the occurrence and development of tumors. We also used a tumor implantation mouse model to show that exosomes containing miR-155 significantly augment the growth rate of the vasculature and tumors in vivo. Our results illustrate the potential mechanism between miR-155 and angiogenesis in GC. These findings contribute to our understanding of the function of miR-155 and exosomes for GC therapy. Keywords: exosomes, miR-155, c-MYB, angiogenesis, VEGF