Macrophage-derived exosomes in cancers: Biogenesis, functions and therapeutic applications

Macrophages are fundamental to promote tumorigenesis, tumor development and metastasis, and chemotherapy resistance through modulating tumor microenvironment and cancer cells. Recently, increasing studies have shown that exosomes could play a crucial role in orchestrating the crosstalk between macrophages and cancer cells. Exosomes, as one of the extracellular vehicles, deliver a diverse cast of molecules including lipids, proteins, and nucleic acids, etc. to the targeted cells to exert pleiotropic effects. The macrophage-derived exosomes have heterogeneity in different cancers and play paradoxical roles in suppressing and promoting tumors mainly via post-transcriptional control and regulating the phosphorylation of proteins in the recipient cells. Meanwhile, exosomes secreted by different phenotypes of macrophages provide diverse therapeutic options. Thus, in this review, we summarized the latest progress in outlining the current understanding of macrophage-derived exosomal biogenesis and mechanisms in mediating cancer progression, as well as their potential clinical applications.