Isolation of tumor-derived extracellular vesicles from dogs affected by malignant brain tumors and in vivo tumor tropism: preliminary results.
Vincenti S*1, Villa A2, De Mitri Z2, Sironi L3, Castiglioni L3, Mazzaferro V4, Ciana P2
1Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland, 2Department of Health Sciences, University of Milan, Milan, Italy, 3Department of Pharmaceutic Sciences, University of Milan, Milan, Italy, 4Department of Oncology and Hemato-Oncology, University of Milan and HPB surgery and Liver Transplantation, Istituto Nazionale Tumori IRCCS Foundation (INT), Milan, Italy.
Objectives:
Canine and human brain tumors share similar incidence and prognosis. Recent studies demonstrated the capacity of human patients-derived extracellular vesicles (PDEVs) to be loaded with contrast agents and show tumor tropism in mice. To date, no study has verified the tropism in vivo in canine brain tumor-derived EVs (cBTEVs). We propose to verify the feasibility of isolating cBTEVs and establish a safe protocol in the canine patient for their possible use as marker and drug delivery tools in clinical applications.
Methods:
To test the functionality of cBTEVs, these were loaded with indocyanine green (Icg- cBTEVs), iohexol (Iox-cBTEVs) and gadolinium (Gad-cBTEVs) and injected in murine models of cancer for in vivo fluorescence, computed tomography and magnetic resonance (MRI) imaging, for biodistribution studies. Then, isolation protocol for cBTEVs from dogs affected by brain tumors was optimized to ensure sterility, for its clinical applications.
Results:
Biodistribution analysis in mice showed that Icg-, Iox- and Gad-cBTEVs injected in murine models of subcutaneous tumors accumulated solely in the neoplastic tissue even when evaluated 24 hours after cBTEVs injection. All the microbiology tests made on the cBTEVs were negative confirming the sterility and safety of our protocol.
Conclusions:
We confirmed Icg-, Iox- and Gad-BTEVs cross-species and heterologous selective tumor tropism. Importantly we established a safe protocol to isolate and load autologous cBTEVs with different markers to proceed with the clinical test phase. These important results suggest potential use of cBTEVs as a theranostic tool in face of canine brain tumors with future translational medicine applications.