Exosomes, membranous nanovesicles, are identified to 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 the expression of miR-155 and c-MYB was negatively correlated in GC and c-MYB was a direct target of miR-155. We next characterized the promotion effect of exosome-delivered miR-155 on angiogenesis and tumor growth in GC. We found that the miR-155 could inhibit c-MYB but increase vascular endothelial growth factor (VEGF) expression, and promote the growth, metastasis, and tube formation of vascular cells, as the reason of 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. In a word, our results illustrated the potential mechanism between miR-155 and angiogenesis in GC. These findings contribute to our understanding of the functions of miR-155 and exosomes as a carrier for therapy of GC.

外泌体，即膜状纳米囊泡，被鉴定为天然携带蛋白质、mRNA 和 microRNA (miRNA)，并在肿瘤发病机制中发挥重要作用。在这里，我们发现胃癌 (GC) 细胞衍生的外泌体可以作为载体传递 miR-155 以促进 GC 中的血管生成。在本研究中，我们首先检测到 miR-155 的表达与 c-MYB 在 GC 中呈负相关，c-MYB 是 miR-155 的直接靶标。我们接下来描述了外泌体传递的 miR-155 对 GC 中血管生成和肿瘤生长的促进作用。我们发现miR-155可以抑制c-MYB但增加血管内皮生长因子（VEGF）的表达，促进血管细胞的生长、转移和管状形成，是肿瘤发生和发展的原因。我们还使用肿瘤移植小鼠模型来证明含有 miR-155 的外泌体显着增加了体内血管系统和肿瘤的生长速率。总之，我们的结果说明了 miR-155 与 GC 中血管生成之间的潜在机制。这些发现有助于我们理解 miR-155 和外泌体作为 GC 治疗载体的功能。