Ephrin type-A receptor 2 on tumor-derived exosomes enhances angiogenesis through the activation of MAPK signaling.

Abstract

Exosomes are potent players in the development of metastases and they play an important role in cancer angiogenesis and exacerbation. However, it is unclear how proteins on exosomes affect development of blood vessel networks. In this study, we focused on relationships between membrane proteins on exosomes and angiogenesis using human umbilical vein endothelial cells (HUVEC). Lung tumor cell-derived exosomes induced tube formation and growth of endothelial cells in vitro in a dose-dependent manner involving MAPK activation, but this was not seen in normal lung epithelial cells. Ephrin type-A receptor 2 (EphA2) was identified by proteomic analysis and an inhibition assays showed it is a major MAPK activator on exosomes. Thus EphA2 on exosomes participates in angiogenesis as a ligand of the ephrin signaling pathway. These results support the development of novel therapeutic strategies such as blockade of remote cancer communications through exosomes.