Extracellular Vesicles in Lung Cancer: Prospects for Diagnostic and Therapeutic Applications

SIMPLE SUMMARY: Extracellular vesicles (EVs) are extensively distributed in various biological fluids, and contain diverse bioactive molecules including proteins, nucleic acids and lipids. They are considered to provide high stability to the associated molecular cargoes because of encapsulation by the lipid bilayer, making them ideal for liquid biopsy and as a drug delivery system. Moreover, EVs can affect immunomodulatory functions, including antigen presentation and immune activation and suppression. Inhibiting the production of tumor-derived EVs can support tumor immunity, and immune cell-derived EVs can be used as an anticancer vaccine. This review summarizes the biological functions and isolation methods of EVs, and explores their diagnostic and therapeutic applications in lung cancer. ABSTRACT: Extracellular vesicles (EVs) are nano-sized lipid-bound particles containing proteins, nucleic acids and metabolites released by cells. They have been identified in body fluids including blood, saliva, sputum and pleural effusions. In tumors, EVs derived from cancer and immune cells mediate intercellular communication and exchange, and can affect immunomodulatory functions. In the context of lung cancer, emerging evidence implicates EV involvement during various stages of tumor development and progression, including angiogenesis, epithelial to mesenchymal transformation, immune system suppression, metastasis and drug resistance. Additionally, tumor-derived EVs (TDEs) have potential as a liquid biopsy source and as a means of therapeutic targeting, and there is considerable interest in developing clinical applications for EVs in these contexts. In this review, we consider the biogenesis, components, biological functions and isolation methods of EVs, and the implications for their clinical utility for diagnostic and therapeutic applications in lung cancer.