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.
Pathologist Pathogenesis, LLC PO Box 140164, Gainesville, FL, 32614, United States.
Vet Immunol Immunopathol. 2021 Feb;232:110169. doi: 10.1016/j.vetimm.2020.110169. Epub 2020 Dec 15.
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.
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.
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.
免疫靶向疗法正在成功地应用于癌症的临床实践中。特别是检查点抑制剂被用于调节实体瘤的免疫微环境。我们试图确定 PD-L1、HVEM 和 B7H3 在人类和犬骨肉瘤中的表达，并将表达与自然发生的犬骨肉瘤的临床特征和肿瘤浸润淋巴细胞相关联。
使用流式细胞术测量五种人源和三种犬源细胞系的配体表面表达。免疫组织化学用于检测 37 例未经治疗的犬骨肉瘤患者肿瘤样本中配体和淋巴细胞标志物的表达。
所有细胞系在两种物种中均以不同水平表达所有三种配体。转移病变与患者肿瘤样本中所有三种配体的高表达相关。PD-L1 表达与 B7H3 和 HVEM 表达强烈相关，而 HVEM 和 B7H3 之间呈弱相关。虽然肿瘤周围 T 细胞的表达与 PD-L1 和 HVEM 肿瘤表达呈正相关，但肿瘤内 T 细胞的存在却很少见。此外，尽管肿瘤周围 T 细胞的对数倍增加，但 T 细胞在转移病变中的肿瘤内穿透程度最大。总之，PD-L1、HVEM 和 B7H3 在骨肉瘤中表达，转移性疾病病变表达水平更高。我们首次表明，这些在骨肉瘤细胞上表达的配体彼此之间以及与肿瘤周围 T 细胞浸润呈正相关。此外，骨肉瘤似乎是一个肿瘤内免疫荒漠，对效应 T 细胞有明显的抵抗作用。多种针对检查点的药物已在临床实践中使用，可能对骨肉瘤具有免疫调节作用。
