Shin Chansu, Imamura Masaru, Kasahara Yasushi, Suzuki Yuko, Baba Minori, Kubo Nobuhiro, Hosokai Ryosuke, Iwabuchi Haruko, Murayama Yudai, Kawashima Hiroyuki, Ogose Akira, Mihara Keichiro, Saitoh Akihiko, Imai Chihaya
Department of Pediatrics, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Niigata 951‑8510, Japan.
Division of Orthopedic Surgery, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Niigata 951‑8510, Japan.
Mol Med Rep. 2025 Sep;32(3). doi: 10.3892/mmr.2025.13608. Epub 2025 Jul 11.
The clinical application of T cells engineered with chimeric antigen receptors (CARs) for solid tumors is challenging. A major reason for this involves tumor immune evasion mechanisms, including the high expression of immune checkpoint molecules, such as the programmed death 1 (PD‑1) ligands PD‑L1 and PD‑L2. The inducible expression of PD‑L1 in tumors has been observed after CAR‑T‑cell infusion, even in tumors natively not expressing PD‑L1. Furthermore, numerous types of pediatric cancer do not have suitable targets for CAR‑T‑cell therapy. Therefore, the present study aimed to develop novel CAR‑T cells that target PD‑L1 and PD‑L2, and to evaluate their efficacy against pediatric solid tumors. A novel CAR harboring the immunoglobulin V‑set domain of the human PD‑1 receptor as an antigen binding site (PD‑1 CAR‑T) was developed without using a single‑chain variable fragment. PD‑1 CAR‑T cells were successfully manufactured by adding an anti‑PD‑1 antibody, nivolumab, to the ex vivo expansion culture to prevent fratricide during the manufacturing process due to the inducible expression of PD‑L1 in activated human T cells. The expression of PD‑L1 (and PD‑L2 to a lesser extent) was revealed to be highly upregulated in various pediatric solid tumor cells, which displayed no or very low expression initially, on exposure to interferon‑γ and/or tumor necrosis factor‑α, which are cytokines secreted by tumor‑infiltrating T cells. Furthermore, PD‑1 CAR-T cells exhibited strong cytotoxic activity against pediatric solid tumor cells expressing PD‑L1 and PD‑L2. Conversely, the effect of PD‑1 CAR‑T cells was significantly attenuated against PD‑L1‑positive cells coexpressing CD80, suggesting that the toxicity of PD‑1 CAR‑T cells to normal immune cells, including antigen presenting cells, can be minimized. In conclusion, PD‑1 ligands are promising therapeutic targets for pediatric solid tumors. PD‑1 CAR‑T cells, either alone or in combination with CAR‑T cells with other targets, represent a potential treatment option for solid tumors.
嵌合抗原受体（CAR）工程化T细胞在实体瘤中的临床应用具有挑战性。主要原因涉及肿瘤免疫逃逸机制，包括免疫检查点分子的高表达，如程序性死亡1（PD-1）配体PD-L1和PD-L2。在CAR-T细胞输注后，已观察到肿瘤中PD-L1的诱导性表达，即使在原本不表达PD-L1的肿瘤中也是如此。此外，许多类型的儿童癌症没有适合CAR-T细胞治疗的靶点。因此，本研究旨在开发靶向PD-L1和PD-L2的新型CAR-T细胞，并评估其对儿童实体瘤的疗效。开发了一种新型CAR，其具有人PD-1受体的免疫球蛋白V区结构域作为抗原结合位点（PD-1 CAR-T），且未使用单链可变片段。通过在体外扩增培养中添加抗PD-1抗体纳武单抗成功制备了PD-1 CAR-T细胞，以防止由于活化的人T细胞中PD-L1的诱导性表达而在制备过程中发生自相残杀。结果显示，在暴露于肿瘤浸润T细胞分泌的细胞因子干扰素-γ和/或肿瘤坏死因子-α后，各种儿童实体瘤细胞中PD-L1（以及程度较轻的PD-L2）的表达被高度上调，这些细胞最初不表达或表达极低。此外，PD-1 CAR-T细胞对表达PD-L1和PD-L2的儿童实体瘤细胞表现出强大的细胞毒性活性。相反，PD-1 CAR-T细胞对共表达CD80的PD-L1阳性细胞的作用明显减弱，这表明PD-1 CAR-T细胞对包括抗原呈递细胞在内的正常免疫细胞的毒性可以降至最低。总之，PD-1配体是儿童实体瘤有前景的治疗靶点。PD-1 CAR-T细胞单独或与其他靶点的CAR-T细胞联合使用，代表了实体瘤的一种潜在治疗选择。
