Isolation and Fluorescent Labeling of Extracellular Vesicles from Cultured Tumor Cells.

Extracellular vesicles (EVs), comprising exosomes, ectosomes, and apoptotic bodies, are an important component of molecular cell-to-cell communication, and are critically involved in the pathophysiology of various diseases, including tumors. In order to study the interaction of tumor cell-derived EVs with their target cells and to investigate their biological functions in comparison to other tumor cell-released factors, efficient isolation of EVs from cultured tumor cells, as well as fluorescent labeling of these EVs, is often necessary. In addition, EVs and EV-like particles are emerging as versatile vehicles for the delivery of therapeutic substances. Here, we describe an easy size exclusion chromatography-based method to isolate EVs from the mouse melanoma cell line B16F10 that yields highly enriched EV samples for subsequent applications such as molecular and functional studies. Our protocol also includes an optional labeling step with the lipophilic dye DiD, which allows tracking of EV uptake by recipient cells in vitro and in vivo.