Tandem incorporation of a novel DAP10 chimeric receptor T cells to overcome tumor heterogeneity

Although chimeric antigen receptor T (CAR-T) cells have achieved remarkable successes in hematological malignancies, the efficacies of CAR-T cells against solid tumors remains unsatisfactory. Heterogeneous antigen expression is one of the obstacles on its effective elimination of solid cancer cells. DNAX-activating protein 10 (DAP10) interacts with natural killer group 2D (NKG2D), acting as an adaptor, which targeting various of malignant cells for surveillance. Here, we designed a DAP10 chimeric receptor that utilized native NKG2D on T cells to target NKG2D ligand-expressing cancer cells. We then tandemly incorporated it with glypican 3 (GPC3) scFv thus to construct a dual-antigen targeting system. T cells expressing DAP10 chimeric receptor (DAP10-T cells) displayed with an enhancement on both cytotoxicity and cytokine secretion against solid cancer cell lines, and its tandem connection with GPC3 scFv (CAR GPC3-DAP10-T cells) exhibited a dual-antigen targeting capacity on eliminating heterogeneous cancer cells in vitro and suppressing the growth of heterogeneous cancer in vivo. Thus, this novel dual-targeting system enabled a high efficacy on killing cancer cells and extended the recognition profile of CAR-T towards tumors, which providing a potential strategy on treatment of solid cancer clinically.

尽管嵌合抗原受体T（chimeric antigen receptor T, CAR-T）细胞在血液系统恶性肿瘤治疗中已取得显著成效，但其针对实体瘤的治疗效果仍不尽如人意。抗原表达异质性是其有效清除实体肿瘤细胞的障碍之一。DNAX激活蛋白10（DNAX-activating protein 10, DAP10）可作为衔接蛋白与自然杀伤细胞组2D受体（natural killer group 2D, NKG2D）结合，靶向多种恶性肿瘤细胞以实现免疫监视。本研究设计了一种DAP10嵌合受体，利用T细胞表面天然存在的NKG2D靶向表达NKG2D配体的肿瘤细胞。随后将其与磷脂酰肌醇蛋白聚糖3（glypican 3, GPC3）单链抗体片段（single-chain variable fragment, scFv）串联融合，构建了双抗原靶向系统。表达DAP10嵌合受体的T细胞（DAP10-T细胞）对实体肿瘤细胞系的细胞毒性与细胞因子分泌能力均有所增强；而其与GPC3 scFv串联融合得到的CAR GPC3-DAP10-T细胞，在体外可实现双抗原靶向清除异质性肿瘤细胞，在体内可抑制异质性实体瘤的生长。综上，这种新型双靶向系统可高效杀伤肿瘤细胞，拓展了CAR-T细胞对肿瘤的识别谱，为临床实体瘤治疗提供了潜在策略。