title: Procoagulant and immunogenic properties of melanoma exosomes, microvesicles and apoptotic vesicles.
abstract: Extracellular vesicles (EV) are lipid particles released from eukaryotic cells into the extracellular fluid. Depending on the cell type or mechanism of release, vesicles vary in form and function and exert distinct functions in coagulation and immunity. Tumor cells may constitutively shed vesicles known as exosomes or microvesicles (MV). Alternatively, apoptosis induces the release of apoptotic blebs or vesicles (ApoV) from the plasma membrane. EV have been implicated in thrombotic events (the second highest cause of death in cancer patients) and tumor vesicles contribute to the anti-cancer immune response. In this study, we utilized the well characterized B16 melanoma model to determine the molecular composition and procoagulant and immunogenic potential of exosomes, MV and ApoV. Distinct patterns of surface and cytoplasmic molecules (tetraspanins, integrins, heat shock proteins and histones) were expressed between the vesicle types. Moreover, in vitro coagulation assays revealed that membrane-derived vesicles, namely MV and ApoV, were more procoagulant than exosomes-with tissue factor and phosphatidylserine critical for procoagulant activity. Mice immunized with antigen-pulsed ApoV and challenged with B16 tumors were protected out to 60 days, while lower protection rates were afforded by MV and exosomes. Together the results demonstrate distinct phenotypic and functional differences between vesicle types, with important procoagulant and immunogenic functions emerging for membrane-derived MV and ApoV versus endosome-derived exosomes. This study highlights the potential of EV to contribute to the prothrombotic state, as well as to anti-cancer immunity.
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin, Otago, New Zealand.
authors.forename: Morad-Rémy
authors.initials: MR
authors.lastname: Muhsin-Sharafaldine
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin, Otago, New Zealand.
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Saunderson
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin, Otago, New Zealand.
authors.forename: Amy C
authors.initials: AC
authors.lastname: Dunn
authors.affiliation: Department of Pathology, University of Otago, Dunedin, Otago, New Zealand.
authors.forename: James M
authors.initials: JM
authors.lastname: Faed
authors.affiliation: Centre for Protein Research, University of Otago, Dunedin, Otago, New Zealand.
authors.forename: Torsten
authors.initials: T
authors.lastname: Kleffmann
authors.affiliation: Department of Microbiology and Immunology, University of Otago, Dunedin, Otago, New Zealand.|Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, Dunedin, Otago, New Zealand.
authors.forename: Alexander D
authors.initials: AD
authors.lastname: McLellan
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000276:immunology*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000276:immunology* / Q000473:pathology; D055252:Cell-Derived Microparticles / Q000276:immunology* / Q000473:pathology / Q000648:ultrastructure; D020285:Cryoelectron Microscopy; D055354:Exosomes / Q000276:immunology* / Q000473:pathology / Q000648:ultrastructure; D005434:Flow Cytometry; D008545:Melanoma / Q000276:immunology / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010718:Phosphatidylserines / Q000378:metabolism; D040901:Proteomics; D013925:Thromboplastin / Q000378:metabolism; D013927:Thrombosis / Q000473:pathology*; D023041:Xenograft Model Antitumor Assays
chemical_list: D010718:Phosphatidylserines; D013925:Thromboplastin
keywords: apoptotic vesicles; cancer immunity; coagulation; tissue factor; tumor vesicles