基于胞外区段重排增强双特异性CART细胞抗瘤效能的新策略和机制研究

嵌合抗原受体修饰的T细胞（CART）在治疗血液系统恶性肿瘤方面表现出良好疗效，但对实体瘤的治疗仍面临巨大挑战。除肿瘤微环境因素外，肿瘤细胞异质性是导致现有CART难以突破实体瘤疗效瓶颈的重要原因。鉴于此，单纯依靠优化CAR内部结构提高抗瘤活性显然不能从根本上改变CART治疗实体瘤现状。双靶点CART具有抗原覆盖度更广的优势，此外，通过胞外区段优化重排可让双靶点CART兼备更强的抗瘤活性。前期，我们应用此策略已成功筛选到具有持久高效抗瘤能力的CD19/CD20双特异性CART。基于此，本项目拟：1）通过胞外区段重排策略构建并筛选具有强抗瘤活性的EGFR/CD133双特异性CAR结构；2）从分子水平深入探讨双特异性CAR强效抗瘤的潜在机制；3）实验动物水平确证EGFR/CD133双特异性CART在清除异质性肿瘤细胞中的功能作用。本项目的完成将为改善CART在实体瘤中的临床疗效奠定基础。

Chimeric antigen receptor modified T cells (CART) have shown good efficacy in the treatment of hematological malignancies, but the treatment of solid tumors still faces great challenges. In addition to tumor microenvironmental factors, tumor cell heterogeneity is an important reason why it is difficult for the existing CART to break through the bottleneck of the curative effect of solid tumors. In view of this, relying solely on optimizing the internal structure of CAR to improve anti-tumor activity obviously cannot fundamentally change the current status of CART treatment of solid tumors. Dual-target CART has the advantage of wider coverage of antigens. In addition, the optimized rearrangement of the extracellular segment allows dual-target CART to have stronger anti-tumor activity. In the early stage, we applied this strategy and successfully screened CD19/CD20 dual-specific CART with long-lasting and high-efficiency anti-tumor ability. Based on this, this project intends to: 1) Construct and screen the EGFR/CD133 bispecific CAR structure with strong anti-tumor activity through the strategy of extracellular segment rearrangement; 2) In-depth study of the strong anti-tumor effect of bispecific CAR at the molecular level 3) Experimental animal level confirms the functional role of EGFR/CD133 bispecific CART in eliminating heterogeneous tumor cells. The completion of this project will lay the foundation for improving the clinical efficacy of CART in solid tumors.