[Progress in immune regulation involving exosomes in hypoxic tumor microenvironment]

Hypoxia is a key characteristic of solid malignant tumor microenvironment. Exosomes secreted by tumor cells as well as stromal cells are important components of the tumor microenvironment. Hypoxia regulates the formation, contents loading, release and biological functions of exosomes. In the hypoxic microenvironment, tumor cell-derived exosomes can deliver important differentially-expressed molecular cargoes to a variety of immune cells and regulate these cells activity to facilitate the growth of tumors by inducing M2 polarization of macrophages, expansion of regulatory T cells, activation of myeloid-derived suppressor cells, and inhibition of cytotoxicity in natural killer cells. To elucidate the interaction mediated by exosomes between tumor cells and immune cells under hypoxia tumor microenvironment and the underlying mechanisms by which exosomes regulate anti-tumor immunity will provide reference for the application of exosomes in tumor vaccines, anti-cancer drug delivery and combined immunotherapy.