Harvey W. Cushing Neuro-oncology Laboratories (HCNL), Department of Neurosurgery, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts.
Center for Stem Cell Therapeutics and Imaging (CSTI), Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts.
Clin Cancer Res. 2019 Jan 1;25(1):290-299. doi: 10.1158/1078-0432.CCR-18-2311. Epub 2018 Oct 2.
Glioblastoma (GBM) is resistant to standard of care. Immune checkpoints inhibitors (such as anti-PD-1 mAbs) efficiently restore antitumor T-cell activity. We engineered a new oncolytic herpes simplex virus (oHSV) expressing a single-chain antibody against PD-1 (scFvPD-1) to evaluate its efficacy in mouse models of GBM.
NG34scFvPD-1 expresses the human gene transcriptionally controlled by the Nestin promoter to allow replication in GBM cells and a scFvPD-1 cDNA transcriptionally controlled by the CMV promoter. ELISA assays were performed to detect binding of scFvPD-1 to mouse and human PD-1. cytotoxicity and replication assays were performed to measure NG34scFvPD-1 oncolysis, and scFvPD-1 expression and secretion were determined. survival studies using orthotopic mouse GBM models were performed to evaluate the therapeutic potency of NG34scFvPD-1.
NG34scFvPD-1-infected GBM cells express and secrete scFvPD-1 that binds mouse PD-1. The introduction of the scFvPD-1 sequence in the viral backbone does not alter the oncolytic properties of NG34scFvPD-1. NG34scFvPD-1 treatment improved the survival with a tail of durable survivorship in 2 syngeneic immunocompetent mouse models of GBM. Mice that survived the first GBM challenge rejected the second challenge of GBM when implanted in the contralateral hemisphere. However, this was not true when athymic mice were employed as the recipients of the second challenge, consistent with the need for an intact immune system to obtain a memory response.
NG34scFvPD-1 treatment induces a durable antitumor response in 2 preclinical mouse models of GBM with evidence for antitumor memory.
胶质母细胞瘤（GBM）对标准治疗有抵抗力。免疫检查点抑制剂（如抗 PD-1 mAb）有效地恢复了抗肿瘤 T 细胞的活性。我们设计了一种新的表达针对 PD-1 的单链抗体的溶瘤单纯疱疹病毒（oHSV）（scFvPD-1），以评估其在 GBM 小鼠模型中的疗效。
NG34scFvPD-1 表达人类基因，转录受巢蛋白启动子控制，允许在 GBM 细胞中复制，并转录 scFvPD-1 cDNA，转录受 CMV 启动子控制。通过 ELISA 检测 scFvPD-1 与人及小鼠 PD-1 的结合。通过细胞毒性和复制检测来评估 NG34scFvPD-1 的溶瘤作用，并确定 scFvPD-1 的表达和分泌。通过原位 GBM 小鼠模型进行生存研究，以评估 NG34scFvPD-1 的治疗潜力。
NG34scFvPD-1 感染的 GBM 细胞表达并分泌与小鼠 PD-1 结合的 scFvPD-1。在病毒骨架中引入 scFvPD-1 序列不会改变 NG34scFvPD-1 的溶瘤特性。NG34scFvPD-1 治疗可改善生存，在 2 种同源免疫活性的 GBM 小鼠模型中延长了存活时间。在对侧半球植入时，存活的小鼠拒绝第二次 GBM 挑战。然而，当使用无胸腺小鼠作为第二次挑战的接受者时，情况并非如此，这与获得记忆反应需要完整的免疫系统一致。
NG34scFvPD-1 治疗在 2 种 GBM 临床前小鼠模型中诱导持久的抗肿瘤反应，并证明存在抗肿瘤记忆。
