Department of Hematology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo, Japan.
Department of Orthopaedic Surgery, Juntendo University School of Medicine, Bunkyo-ku, Tokyo, Japan.
Cancer Immunol Res. 2021 Oct;9(10):1175-1186. doi: 10.1158/2326-6066.CIR-21-0193. Epub 2021 Aug 12.
The prognosis of Ewing sarcoma caused by fusion is poor, especially after metastasis. Although therapy with CTLs targeted against altered EWS/FLI1 sequences at the gene break/fusion site may be effective, CTLs generated from peripheral blood are often exhausted because of continuous exposure to tumor antigens. We addressed this by generating induced pluripotent stem cell (iPSC)-derived functionally rejuvenated CTLs (rejT) directed against the neoantigen encoded by the fusion gene. In this study, we examined the antitumor effects of EWS/FLI1-rejTs against Ewing sarcoma. The altered amino acid sequence at the break/fusion point of EWS/FLI1, when presented as a neoantigen, evokes an immune response that targets sarcoma. Although the frequency of generated EWS/FLI1-specific CTLs was only 0.003%, we successfully established CTL clones from a healthy donor. We established iPSCs from a EWS/FLI1-specific CTL clone and redifferentiated them into EWS/FLI1-specific rejTs. To evaluate cytotoxicity, we cocultured EWS/FLI1-rejTs with Ewing sarcoma cell lines. EWS/FLI1-rejTs rapidly and continuously suppressed the proliferation of Ewing sarcoma for >40 hours. Using a Ewing sarcoma xenograft mouse model, we verified the antitumor effect of EWS/FLI1-rejTs via imaging, and EWS/FLI1-rejTs conferred a statistically significant survival advantage. "Off-the-shelf" therapy is less destructive and disruptive than chemotherapy, and radiation is always desirable, particularly in adolescents, whom Ewing sarcoma most often affects. Thus, EWS/FLI1-rejTs targeting a Ewing sarcoma neoantigen could be a promising new therapeutic tool.
EWS/FLI1 融合导致的尤文肉瘤预后较差，尤其是发生转移后。虽然针对基因断裂/融合部位改变的 EWS/FLI1 序列的 CTLs 治疗可能有效，但由于持续暴露于肿瘤抗原，来自外周血的 CTLs 通常会衰竭。我们通过生成针对由融合基因编码的新抗原的诱导多能干细胞 (iPSC) 衍生的功能再生 CTL (rejT) 来解决这个问题。在这项研究中，我们研究了针对尤文肉瘤的 EWS/FLI1-rejT 的抗肿瘤作用。当 EWS/FLI1 的断裂/融合点的改变氨基酸序列被呈递为新抗原时，会引发针对尤文肉瘤的免疫反应。虽然生成的 EWS/FLI1 特异性 CTL 的频率仅为 0.003%，但我们还是成功地从健康供体中建立了 CTL 克隆。我们从 EWS/FLI1 特异性 CTL 克隆中建立了 iPSCs，并将其重新分化为 EWS/FLI1 特异性 rejT。为了评估细胞毒性，我们将 EWS/FLI1-rejT 与尤文肉瘤细胞系共培养。EWS/FLI1-rejT 迅速且持续地抑制尤文肉瘤的增殖超过 40 小时。通过尤文肉瘤异种移植小鼠模型，我们通过成像验证了 EWS/FLI1-rejT 的抗肿瘤作用，并且 EWS/FLI1-rejT 赋予了统计学上显著的生存优势。“现成的”治疗方法比化疗的破坏性和干扰性更小，而且辐射总是可取的，尤其是在青少年中，尤文肉瘤最常影响他们。因此，针对尤文肉瘤新抗原的 EWS/FLI1-rejT 可能是一种有前途的新治疗工具。
