Extracellular vesicles (EVs), lipid bilayer-enclosed structures that contain a variety of biological molecules shed by cells, are increasingly becoming appreciated as a major form of cell-to-cell communication. Indeed, EVs have been shown to play important roles in several physiological processes, as well as diseases such as cancer. EVs dock on to the surfaces of recipient cells where they transmit signals from the cell surface and/or transfer their contents into cells to elicit functional responses. EV docking and uptake by cells represent critical, but poorly understood processes.
(A) EVs generated by cancer cells contain a variety of cargo (i.e., protein, RNA, and DNA) that can be transferred to other cells. This causes the phenotypes of recipient cells to change (denoted by the color change) in ways that promote cancer progression. (B) EVs derived from bone marrow or different types of cancer cells accumulate in specific organs in animal models. For example, EVs generated by bone marrow cells accumulate in the kidney where they promote injury recovery (grey arrow and EVs). However, cancer-derived EVs appear to promote metastasis in a variety of organs. Specifically, EVs from melanoma cells preferentially accumulate in the bone, liver, spleen, and lung (green arrows and EVs), EVs from breast cancer cells accumulate in the liver and lungs (pink arrows and EVs), and EVs from pancreatic cancer cells accumulate in the liver, lung, and lymph nodes (blue arrows and EVs).