Proteomic Profiling of the Extracellular Vesicle Chaperone in Cancer.

Molecular chaperones are widely distributed intracellular proteins that play essential roles in maintaining proteome function by assisting in the folding of client proteins. Molecular chaperones, such as heat shock proteins (HSPs), are found intracellularly and extracellularly. Extracellular vesicles (EVs), such as exosomes, contain HSPs and horizontally transfer the functional chaperones into various recipient cells. Besides, mass spectrometry has enabled a comprehensive analysis of exosomal and EV proteins, which is useful in basic biomedical research to clinical biomarker search. We have performed deep proteome analysis of EVs, including exosomes, from metastatic tongue and prostate cancers and detected >700 protein types, including cytoplasmic, ER, mitochondrial, small, and large HSPs. Here, we provide protocols for isolating exosomes/EVs and deep proteome analysis to detect the EV chaperone.