State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
CARsgen Therapeutics, Shanghai, China.
Cancer Immunol Res. 2018 Nov;6(11):1314-1326. doi: 10.1158/2326-6066.CIR-18-0044. Epub 2018 Sep 10.
The heterogeneous expression of EGFRvIII [variant III mutant of epidermal growth factor receptor (EGFR)] in glioblastoma has significant impact on the clinical response to the treatment of EGFRvIII-specific chimeric antigen receptor-engineered T (CAR T) cells. We hypothesized that CAR T cells that could target both EGFRvIII and the form of EGFR expressed on tumor cells, but not EGFR on normal cells, would greatly improve efficacy without inducing on-target, off-tumor toxicity. Therefore, we developed a humanized single-chain antibody, M27, with a single specificity that binds to an epitope found both on wild-type EGFR- and EGFRvIII-overexpressing tumor cells, but not EGFR-expressing normal cells, including primary keratinocytes, on which wild-type EGFR is highly expressed. M27-derived CAR T cells effectively lysed EGFRvIII- or EGFR-overexpressing tumor cells, but showed no observable toxicity on normal cells. Inclusion of the CD137 (4-1BB) costimulatory intracellular domain in the M27-28BBZ CAR provided CAR T cells with higher tumor lysis activity than when not included (as in the M27-28Z CAR). The growth of established EGFR- or EGFRvIII-overexpressing glioma xenografts was suppressed by M27-28BBZ CAR T cells as well. The growth of heterogeneic xenograft tumors, created by mixing EGFR- and EGFR-overexpressing glioblastoma cells, was also effectively inhibited by M27-28BBZ CAR T cells. The survival of mice in the orthotopic models was significantly prolonged after M27-28BBZ CAR T-cell infusion. These results suggested that tumor-selective, bitargeted anti-EGFR/EGFRvIII CAR T cells may be a promising modality for the treatment of patients with EGFR/EGFRvIII-overexpressing glioblastoma. .
表皮生长因子受体 (EGFR) 变体 III 突变体（EGFRvIII）在胶质母细胞瘤中的异质性表达对 EGFRvIII 特异性嵌合抗原受体工程化 T 细胞（CAR T 细胞）治疗的临床反应有重大影响。我们假设，能够同时针对 EGFRvIII 和肿瘤细胞上表达的 EGFR 形式，但不针对正常细胞上的 EGFR 的 CAR T 细胞，将在不引起靶标、脱靶毒性的情况下极大地提高疗效。因此，我们开发了一种人源化单链抗体 M27，它具有单一特异性，可结合野生型 EGFR 和 EGFRvIII 过表达肿瘤细胞上的表位，但不结合表达 EGFR 的正常细胞，包括高表达野生型 EGFR 的原代角质形成细胞。M27 衍生的 CAR T 细胞有效地裂解 EGFRvIII 或 EGFR 过表达的肿瘤细胞，但对正常细胞没有观察到毒性。在 M27-28BBZ CAR 中包含 CD137（4-1BB）共刺激细胞内结构域，使 CAR T 细胞比不包含该结构域（如 M27-28Z CAR）具有更高的肿瘤裂解活性。M27-28BBZ CAR T 细胞也抑制了已建立的 EGFR 或 EGFRvIII 过表达胶质母细胞瘤异种移植物的生长。混合 EGFR 和 EGFR 过表达胶质母细胞瘤细胞的异质异种移植物肿瘤的生长也被 M27-28BBZ CAR T 细胞有效抑制。M27-28BBZ CAR T 细胞输注后，荷瘤小鼠的存活率显著延长。这些结果表明，肿瘤选择性、双靶抗 EGFR/EGFRvIII CAR T 细胞可能是治疗 EGFR/EGFRvIII 过表达胶质母细胞瘤患者的一种有前途的方法。
