Institute for Bio-Medical Convergence, Catholic Kwandong University College of Medicine, Gangneung, Korea.
Department of Laboratory Animal, Catholic Kwandong University International St. Mary's Hospital, Incheon, Korea.
Investig Clin Urol. 2023 Jan;64(1):74-81. doi: 10.4111/icu.20220031.
Programmed cell death protein 1 (PD-1) and ligand programmed death ligand 1 (PD-L1) are important immune-suppressive regulators in the tumor microenvironment. A vaccine-induced immune effect on tumor cells is blunted by the immunosuppressive tumor microenvironment. Therefore, we hypothesized that a dendritic cell (DC) vaccine combined with anti-PD-1 (αPD-1) antibodies could elicit a synergistic anti-tumor immunity in bladder cancer.
We produced a model of subcutaneous transplantation in C3H/HeJ mice by transplanting murine MBT-2 bladder cancer cells. DCs were isolated from normal C3H/HeJ mice, followed by stimulation against MBT-2 lysate before injection. Two weeks later of MBT-2 inoculation, αPD-1 and stimulated DCs were injected two times at one-week interval intraperitoneally and intravenously, respectively. Tumor-infiltrating immune cells and splenocytes were analyzed using flow cytometry. T-cell-mediated anti-tumor responses were measured by interferon (IFN)-γ ELISPOT and lactate dehydrogenase assays.
The mice treated with DC+αPD-1 showed a significant decrease in tumor volume compared to the DC-treated mice and IgG-treated group. Survival of the DC+αPD-1-treated group was improved compared with that of the IgG-treated mice. IFN-γ secretion from splenocytes against tumor cells was significantly increased in the DC+αPD-1 group compared with that of αPD-1-treated mice. The frequency of CD8 and CD4 T-cells in spleens was statistically increased in the DC+αPD-1-treated mice compared to those receiving monotherapy (DC- or αPD-1-treated group).
Our results support the hypothesis that the combination therapy of a DC vaccine and αPD-1 antibodies could enhance the anti-tumor immune response against bladder cancer.
程序性死亡蛋白 1（PD-1）及其配体程序性死亡配体 1（PD-L1）是肿瘤微环境中重要的免疫抑制调节剂。肿瘤微环境中的免疫抑制作用削弱了肿瘤细胞的疫苗诱导免疫效应。因此，我们假设树突状细胞（DC）疫苗联合抗 PD-1（αPD-1）抗体可以在膀胱癌中引发协同的抗肿瘤免疫反应。
我们通过移植鼠 MBT-2 膀胱癌细胞在 C3H/HeJ 小鼠中建立了皮下移植模型。从正常 C3H/HeJ 小鼠中分离出 DC，然后用 MBT-2 裂解物刺激后再进行注射。MBT-2 接种两周后，分别在一周间隔时间内经腹腔和静脉内注射 αPD-1 和刺激的 DC。使用流式细胞术分析肿瘤浸润免疫细胞和脾细胞。通过干扰素（IFN）-γ ELISPOT 和乳酸脱氢酶测定来测量 T 细胞介导的抗肿瘤反应。
与 DC 治疗组和 IgG 治疗组相比，接受 DC+αPD-1 治疗的小鼠肿瘤体积显著减小。与 IgG 治疗组相比，DC+αPD-1 治疗组的生存时间得到了改善。与 αPD-1 治疗组相比，DC+αPD-1 组脾细胞针对肿瘤细胞的 IFN-γ 分泌显著增加。与接受单药治疗（DC 或 αPD-1 治疗组）的小鼠相比，DC+αPD-1 治疗组的 CD8 和 CD4 T 细胞在脾脏中的频率统计学上有所增加。
我们的结果支持这样一种假设，即 DC 疫苗和 αPD-1 抗体的联合治疗可以增强针对膀胱癌的抗肿瘤免疫反应。
