Roles of integrins in regulating metastatic potentials of cancer cell derived exosomes

Purpose of review: Exosomes are nano-sized extracellular vesicles ranging from 30–150 nm in diameter. Exosomes interact with nearby or distantly localized recipient cells by involving ligand/receptor binding at the surface of recipient cells or fusion with plasma membrane of recipient cells. A number of recent literatures support the role of integrins in mediating metastatic process of cancer cell derived exosomes. While exosomes need to dock on the surface of recipient cells to transmit signals or transfer their contents, the process of docking and uptake of exosomes by recipient cells is poorly understood. This review discusses the recent reports that suggest the potential roles of exosomal integrins in mediating docking and uptake of exosomes, and how these processes are related to metastatic potentials of cancer cell derived exosomes. Recent findings: Exosomal integrins (α6β4, α6β1, αvβ5, αvβ3, αvβ6) and exosomal integrin ligands (vinculin, fibronectin) have been recently reported to play roles in cancer metastasis. As exosomes are involved in cell-to-cell communication, integrins and their ligands in cancer cell derived exosomes can contribute to progression by selecting target tissues and triggering integrin mediated signaling cascades to form new metastatic niche. Recent studies also suggest that exosomal integrins and their ligands can be targeted for developing exosome based diagnostics and therapies.