Abstract
Cells release extracellular vesicles (EVs) that can be detected both in vivo and in cell culture medium. Among EVs, exosomes are 50-150 nm vesicles that are systematically packaged into multivesicular bodies for release into the external environment. In cancer, these intentionally packaged exosomes carry a payload of proteins such as RNAs and surface receptors that facilitate the reprogramming of proximal cells to assemble a protumor microenvironment. Exosomes have been implicated as an important intermediary extracellular communication pathway between cells, including in melanoma. Human melanoma-derived exosomes (HMEX) have been demonstrated to modulate the extracellular environment and inhibit immune cell activation. There are many methods to isolate and enrich for exosomes and the method applied can impact yield and purity of the isolates. In this chapter we describe the REIUS (rapid exosome isolation using ultrafiltration and size exclusion chromatography) method to isolate HMEX from melanoma cell cultures and then demonstrate their enrichment using molecular and microscopic approaches.