Department of Diagnostic Sciences, Ghent University, Ghent, Belgium.
Cancer Research Institute Ghent (CRIG), Ghent, Belgium.
Cancer Immunol Res. 2024 Sep 3;12(9):1236-1251. doi: 10.1158/2326-6066.CIR-23-0677.
CD70 is an attractive target for chimeric antigen receptor (CAR) T-cell therapy for the treatment of both solid and liquid malignancies. However, the functionality of CD70-specific CAR T cells is modest. We optimized a CD70-specific VHH-based CAR (nanoCAR). We evaluated the nanoCARs in clinically relevant models in vitro, using co-cultures of CD70-specific nanoCAR T cells with malignant rhabdoid tumor organoids, and in vivo, using a diffuse large B-cell lymphoma patient-derived xenograft (PDX) model. Although the nanoCAR T cells were highly efficient in organoid co-cultures, they showed only modest efficacy in the PDX model. We determined that fratricide was not causing this loss in efficacy but rather CD70 interaction in cis with the nanoCAR-induced exhaustion. Knocking out CD70 in nanoCAR T cells using CRISPR/Cas9 resulted in dramatically enhanced functionality in the diffuse large B-cell lymphoma PDX model. Through single-cell transcriptomics, we obtained evidence that CD70 knockout CD70-specific nanoCAR T cells were protected from antigen-induced exhaustion. In addition, we demonstrated that wild-type CD70-specific nanoCAR T cells already exhibited signs of exhaustion shortly after production. Their gene signature strongly overlapped with gene signatures of exhausted CAR T cells. Conversely, the gene signature of knockout CD70-specific nanoCAR T cells overlapped with the gene signature of CAR T-cell infusion products leading to complete responses in chronic lymphatic leukemia patients. Our data show that CARs targeting endogenous T-cell antigens negatively affect CAR T-cell functionality by inducing an exhausted state, which can be overcome by knocking out the specific target.
CD70 是嵌合抗原受体 (CAR) T 细胞治疗实体瘤和液体恶性肿瘤的有吸引力的靶点。然而，CD70 特异性 CAR T 细胞的功能有限。我们优化了一种 CD70 特异性 VHH 基 CAR（纳米 CAR）。我们在体外使用 CD70 特异性纳米 CAR T 细胞与恶性横纹肌样瘤类器官的共培养，以及体内使用弥漫性大 B 细胞淋巴瘤患者来源异种移植（PDX）模型来评估纳米 CAR。虽然纳米 CAR T 细胞在类器官共培养中非常有效，但在 PDX 模型中仅显示出适度的疗效。我们确定同种型细胞杀伤不是导致这种疗效丧失的原因，而是纳米 CAR 诱导的衰竭中 CD70 的顺式相互作用。使用 CRISPR/Cas9 敲除纳米 CAR T 细胞中的 CD70 导致弥漫性大 B 细胞淋巴瘤 PDX 模型中的功能显著增强。通过单细胞转录组学，我们获得了证据表明，CD70 敲除的 CD70 特异性纳米 CAR T 细胞免受抗原诱导的衰竭。此外，我们证明，野生型 CD70 特异性纳米 CAR T 细胞在产生后不久就表现出衰竭的迹象。它们的基因特征与衰竭的 CAR T 细胞的基因特征强烈重叠。相反，CD70 敲除的 CD70 特异性纳米 CAR T 细胞的基因特征与导致慢性淋巴细胞白血病患者完全缓解的 CAR T 细胞输注产品的基因特征重叠。我们的数据表明，靶向内源性 T 细胞抗原的 CAR 通过诱导衰竭状态来负性影响 CAR T 细胞功能，通过敲除特定靶标可以克服这种状态。
