Fig. 3

Synthesis of CDEs and its interactions with cancer cells. Exosomes are defined as EVs with a diameter of 40–160 nm carrying various biomolecules including nucleic acids, lipids, metabolites, and cell-surface proteins. Exosome formation depends on three important processes: endocytosis of various biomolecules and the formation of early sorting endosome (ESE) followed by late sorting endosome (LSE), and then synthesis of intracellular MVBs containing intraluminal vesicles (ILVs). Finally, MVBs fuse with the cell membrane, releasing exosome contents to the extracellular regions via exocytosis. Signal interaction patterns are mainly determined by exosome-transported molecules in three ways: direct cell membrane fusion with recipient cells, endocytosis, and internalization triggered by the binding of specific molecules on the exosome surface to corresponding receptor cells (receptor-ligand interaction)