Effects of exosomes on pre-metastatic niche formation in tumors

Yaxin Guo†,
Xiang Ji†,
Jinbo Liu,
Dandan Fan,
Quanbo Zhou,
Chen Chen,
Weiwei Wang,
Guixian Wang,
Haijiang Wang,
Weitang YuanEmail author,
Zhenyu JiEmail author and
Zhenqiang SunEmail author View ORCID ID profile

†Contributed equally

Molecular Cancer201918:39

https://doi.org/10.1186/s12943-019-0995-1

Received: 11 January 2019
Accepted: 28 February 2019
Published: 11 March 2019

Abstract

A pre-metastatic niche is a microenvironment prepared for the colonization of circulating tumor cells in specific organs. Exosomes are extracellular vesicles with a variety of biological functions. Exosomes play an irreplaceable role in the development of pre-metastatic niches, and mainly function as communication medium. In this review, we analyzed the effects of exosomes on pre-metastatic niches from various perspectives, including inflammation, immune response, angiogenesis, organotropism, matrix remodeling and biomarker expression. In particular, exosomes express programmed death ligand 1 (PD-L1) and cause the immune escape of tumor cells. The immunomodulatory effects of exosomes and their potential in liquid diagnosis have drawn our attention. The potential value of exosomes and pre-metastatic niches will be realized in the field of immunity therapy.