Abstract
Tumor-derived extracellular vesicles (EVs) are emerging as an important component of cancer progression and survival. Tumor-derived EVs have been shown to promote angiogenesis, metastasis, and suppress immune cells both locally and systemically. Microvesicles (MVs) are a subset of EVs that originate from plasma membranes and are 100-1,000nm in diameter. Exosomes are a smaller subset of EVs, 30–150nm in diameter, that originate from the endocytic compartment of their parent cells. In the current study, the molecular cargos and functions of MVs isolated from supernatants of head and neck cancer (HNC) cell lines, PCI13 and SCC-47, were evaluated and compared with exosomes isolated from the same cell lines using mini size-exclusion chromatography. MVs were isolated from the pellet that forms during differential centrifugation. Immunomodulatory molecules (TGF?-1, PD-L1 and Fas-L) were carried by HNC exosomes but were minimally expressed by MVs. MVs co-incubated with Jurkat cells induced apoptosis but at lower level compared to exosomes. Our data shows that tumor derived exosomes and MVs differ in their protein cargo and biologic activity.