Expression of the disialoganglioside GD2 has been identified as a marker antigen associated with a breast cancer stem-like cell (BCSC) phenotype. Here, we report on the evaluation of GD2 as a BCSC-specific target antigen for immunotherapy. GD2 expression was confirmed at variable degree in a set of breast cancer cell lines, predominantly in triple-negative breast cancer (TNBC). To target GD2, we have generated novel anti-GD2 chimeric antigen receptors (GD2-CAR), based on single-chain variable fragments (scFv) derived from the monoclonal antibody (mAb) ch14.18, also known as dinutuximab beta. Expressed on T cells, GD2-CARs mediated specific GD2-dependent T-cell activation and target cell lysis. In contrast to previously described GD2-CARs, no signs of exhaustion by tonic signaling were found. Importantly, application of GD2-CAR expressing T cells (GD2-CAR-T) in an orthotopic xenograft model of TNBC (MDA-MB-231) halted local tumor progression and completely prevented lung metastasis formation. In line with the BCSC model, GD2 expression was only found in a subpopulation (4-6%) of MDA-MB-231 cells before injection. Significant expansion of GD2-CAR-T in tumor-bearing mice as well as T-cell infiltrates in the primary tumor and the lungs were found, indicating site-specific activation of GD2-CAR-T. Our data strongly support previous findings of GD2 as a BCSC-associated antigen. GD2-targeted immunotherapies have been extensively studied in human. In conclusion, GD2-CAR-T should be considered a promising novel approach for GD2-positive breast cancer, especially to eliminate disseminated tumor cells and prevent metastasis formation.

中文翻译：

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GD2 靶向嵌合抗原受体 T 细胞通过消除乳腺癌干细胞样细胞来防止转移形成。

双唾液酸神经节苷脂 GD2 的表达已被确定为与乳腺癌干细胞 (BCSC) 表型相关的标记抗原。在这里，我们报告了 GD2 作为免疫治疗的 BCSC 特异性靶抗原的评估。GD2 表达在一组乳腺癌细胞系中得到不同程度的证实，主要在三阴性乳腺癌 (TNBC) 中。为了靶向 GD2，我们基于源自单克隆抗体 (mAb) ch14.18（也称为 dinutuximab beta）的单链可变片段 (scFv) 生成了新型抗 GD2 嵌合抗原受体 (GD2-CAR)。GD2-CARs 在 T 细胞上表达，介导特定的 GD2 依赖性 T 细胞活化和靶细胞裂解。与之前描述的 GD2-CAR 相比，没有发现强直信号导致的疲惫迹象。重要的，GD2-CAR 表达 T 细胞 (GD2-CAR-T) 在 TNBC (MDA-MB-231) 原位异种移植模型中的应用阻止了局部肿瘤进展并完全阻止了肺转移的形成。与 BCSC 模型一致，GD2 表达仅在注射前的 MDA-MB-231 细胞亚群 (4-6%) 中发现。在荷瘤小鼠中发现 GD2-CAR-T 显着扩增，以及在原发性肿瘤和肺中发现 T 细胞浸润，表明 GD2-CAR-T 的位点特异性激活。我们的数据强烈支持先前发现的 GD2 作为 BCSC 相关抗原。GD2 靶向免疫疗法已在人体中得到广泛研究。总之，GD2-CAR-T 应该被认为是一种有前途的治疗 GD2 阳性乳腺癌的新方法，尤其是在消除播散性肿瘤细胞和防止转移形成方面。