Analysis of Amount, Size, Protein Phenotype and Molecular Content of Circulating Extracellular Vesicles Identifies New Biomarkers in Multiple Myeloma

Abstract

Ilaria Laurenzana,1,* Stefania Trino,1,* Daniela Lamorte,1 Marco Girasole,2 Simone Dinarelli,2 Angelo De Stradis,3 Vitina Grieco,4 Maddalena Maietti,5 Antonio Traficante,5 Teodora Statuto,4 Oreste Villani,6 Pellegrino Musto,6 Alessandro Sgambato,7 Luciana De Luca,4,* Antonella Caivano4,* 1Laboratory of Preclinical and Translational Research, Centro di Riferimento Oncologico della Basilicata (IRCCS-CROB), Rionero in Vulture, PZ, Italy; 2Institute for the Study of the Structure of Matter, National Research Council (CNR), Rome, Italy; 3Institute for Sustainable Plant Protection, National Research Council (CNR), Bari, Italy; 4Laboratory of Clinical Research and Advanced Diagnostics, Centro di Riferimento Oncologico della Basilicata (IRCCS-CROB), Rionero in Vulture, PZ, Italy; 5Unit of Clinical Pathology, Centro di Riferimento Oncologico della Basilicata (IRCCS-CROB), Rionero in Vulture, PZ, Italy; 6Hematology and Stem Cell Transplantation Unit, Centro di Riferimento Oncologico della Basilicata (IRCCS-CROB), Rionero in Vulture, PZ, Italy; 7Scientific Direction, Centro di Riferimento Oncologico della Basilicata (IRCCS-CROB), Rionero in Vulture, PZ, Italy*These authors contributed equally to this workCorrespondence: Antonella CaivanoLaboratory of Clinical Research and Advanced Diagnostics, IRCCS CROB, Rionero in Vulture, 85028, Potenza, ItalyTel [phone]Fax [phone]Email [email protected]: Extracellular vesicles (EVs) are naturally secreted cellular lipid bilayer particles, which carry a selected molecular content. Owing to their systemic availability and their role in tumor pathogenesis, circulating EVs (cEVs) can be a valuable source of new biomarkers useful for tumor diagnosis, prognostication and monitoring. However, a precise approach for isolation and characterization of cEVs as tumor biomarkers, exportable in a clinical setting, has not been conclusively established.Methods: We developed a novel and laboratory-made procedure based on a bench centrifuge step which allows the isolation of serum cEVs suitable for subsequent characterization of their size, amount and phenotype by nanoparticle tracking analysis, microscopy and flow cytometry, and for nucleic acid assessment by digital PCR.Results: Applied to blood from healthy subjects (HSs) and tumor patients, our approach permitted from a small volume of serum (i) the isolation of a great amount of EVs enriched in small vesicles free from protein contaminants; (ii) a suitable and specific cell origin identification of EVs, and (iii) nucleic acid content assessment. In clonal plasma cell malignancy, like multiple myeloma (MM), our approach allowed us to identify specific MM EVs, and to characterize their size, concentration and microRNA content allowing significant discrimination between MM and HSs. Finally, EV associated biomarkers correlated with MM clinical parameters.Conclusion: Overall, our cEV based procedure can play an important role in malignancy biomarker discovery and then in real-time tumor monitoring using minimal invasive samples. From a practical point of view, it is smart (small sample volume), rapid (two hours), easy (no specific expertise required) and requirements are widely available in clinical laboratories.Keywords: extracellular vesicles, biomarkers, hematological malignancies, nanoparticle tracking analysis, flow cytometry, digital PCR

Keywords

• extracellular vesicles
• biomarkers
• hematological malignancies
• nanoparticle tracking analysis
• flow cytometry
• digital pcr