Matthew J Cascio1, Elizabeth M Whitley2, Bikash Sahay3, Galaxia Cortes-Hinojosa4, Lung-Ji Chang5, Jonathan Cowart6, Marc Salute6, Elias Sayour7, Michael Dark8, Zachary Sandoval9, Duane A Mitchell10, Rowan J Milner6. 1. Department of Pediatrics, College of Medicine, University of Florida, Pediatric Hematology/Oncology, University of Florida, 1600 SW Archer Rd, RMHD204, PO Box 100298, Gainesville, FL, 32610, United States. Electronic address: mcascio@ufl.edu. 2. Pathologist Pathogenesis, LLC PO Box 140164, Gainesville, FL, 32614, United States. 3. Department of Infectious Diseases and Pathology, College of Veterinary, Medicine, University of Florida, PO Box 100880, 2015 SW 16th Ave, Gainesville, FL, 32610-0126, United States. 4. School of Veterinary Medicine, Pontifical Catholic University of Chile, Av. Vicuña Mackenna 4860, Macul-Santiago, 7820436, Chile. 5. Professor of Molecular Genetics and Microbiology, University of Florida, P.O. Box 100266, Gainesville, FL, 32610-0266, United States. 6. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, PO Box 100126, 2015 SW 16th Ave, Gainesville, FL, 32610-0126, United States. 7. Department of Pediatrics, College of Medicine, University of Florida, Pediatric Hematology/Oncology, University of Florida, 1600 SW Archer Rd, RMHD204, PO Box 100298, Gainesville, FL, 32610, United States; Department of Neurosurgery, University of Florida, P.O. Box 100265, Gainesville, FL, 32610-0265, United States. 8. Department of Comparative, Diagnostic & Population Medicine, University of Florida, PO Box 100123, 2015 SW 16th Ave, Gainesville, FL, 32610-0123, United States. 9. College of Public Health and Health Professions, University of Florida, 2015 SW 16th Ave, Gainesville, FL, 32608, United States. 10. Department of Neurosurgery, University of Florida, P.O. Box 100265, Gainesville, FL, 32610-0265, United States.
Abstract
BACKGROUND: Immune-targeted therapies are being successfully implemented into cancer clinical practice. In particular checkpoint inhibitors are employed to modulate the immune microenvironment of solid tumors. We sought to determine the expression of PD-L1, HVEM, and B7H3 in human and canine osteosarcoma, and correlate expression with clinical features and tumor infiltrating lymphocytes in naturally-occurring canine osteosarcoma. METHODS: Flow cytometry was used to measure ligand surface expression of five human and three canine cell lines. Immunohistochemistry was utilized for expression of ligands and lymphocyte markers in thirty-seven treatment-naïve canine osteosarcoma patients. RESULTS: All cell lines expressed all three ligands at variable levels in both species. Metastatic lesions were associated with higher expression of all three ligands in patient tumor samples. PD-L1 expression strongly correlated with B7H3 and HVEM expression, while HVEM and B7H3 were weakly correlated. Whereas peritumoral T-cell expression positively correlated with PD-L1 and HVEM tumor expression, the presence of T-cells intratumorally were rare. Furthermore, intratumor penetration by T-cells was greatest in metastatic lesions, despite log-fold increases in peritumoral T-cells. In summary, PD-L1, HVEM, and B7H3 are expressed in osteosarcoma, with metastatic disease lesions expressing higher levels. We show for the first time that these ligands expressed on osteosarcoma cells positively correlate with each other and the presence of peritumoral T cell infiltration. Furthermore, osteosarcoma appears to be an intratumoral immune desert with significant resistance to effector T cells. Multiple agents targeting checkpoints are in clinical practice, and may have immune modulating benefit in osteosarcoma.
BACKGROUND: Immune-targeted therapies are being successfully implemented into cancer clinical practice. In particular checkpoint inhibitors are employed to modulate the immune microenvironment of solid tumors. We sought to determine the expression of PD-L1, HVEM, and B7H3 in human and canineosteosarcoma, and correlate expression with clinical features and tumor infiltrating lymphocytes in naturally-occurring canineosteosarcoma. METHODS: Flow cytometry was used to measure ligand surface expression of five human and three canine cell lines. Immunohistochemistry was utilized for expression of ligands and lymphocyte markers in thirty-seven treatment-naïve canineosteosarcomapatients. RESULTS: All cell lines expressed all three ligands at variable levels in both species. Metastatic lesions were associated with higher expression of all three ligands in patienttumor samples. PD-L1 expression strongly correlated with B7H3 and HVEM expression, while HVEM and B7H3 were weakly correlated. Whereas peritumoral T-cell expression positively correlated with PD-L1 and HVEM tumor expression, the presence of T-cells intratumorally were rare. Furthermore, intratumor penetration by T-cells was greatest in metastatic lesions, despite log-fold increases in peritumoral T-cells. In summary, PD-L1, HVEM, and B7H3 are expressed in osteosarcoma, with metastatic disease lesions expressing higher levels. We show for the first time that these ligands expressed on osteosarcoma cells positively correlate with each other and the presence of peritumoral T cell infiltration. Furthermore, osteosarcoma appears to be an intratumoral immune desert with significant resistance to effector T cells. Multiple agents targeting checkpoints are in clinical practice, and may have immune modulating benefit in osteosarcoma.
Authors: Aryana M Razmara; Sean J Judge; Alicia A Gingrich; Sylvia M Cruz; William T N Culp; Michael S Kent; Robert B Rebhun; Robert J Canter Journal: Front Vet Sci Date: 2021-11-16