靶向L6抗原CART细胞通过自分泌IL-2突变体改善肿瘤免疫微环境提高抗肿瘤作用研究

肿瘤干细胞参与抗放化疗，用CAR T细胞靶向肿瘤干细胞的免疫细胞治疗将是治疗实体瘤的有效途径，但如何提高CAR T瘤体趋向性和瘤内增殖力是亟待解决的关键问题。本课题组一直从事肿瘤干细胞和CAR T研究，并成功获得高效低毒的IL-2突变体，证实其可以增强T细胞的瘤体趋向性和NK细胞的肿瘤杀伤功能提高抗肿瘤效果。我们前期工作还发现小分子化合物诱导的肿瘤干细胞增加了TM4SF1（L6）的表达。本项目将以L6为CAR T细胞治疗靶点，以ICOS-4-1BB为共刺激分子的CAR结构构建能自分泌IL-2突变体的CARL6-IL2M T细胞，研究其体外表型、迁移、扩增和肿瘤杀伤功能，考察在用NSG小鼠和免疫正常小鼠构建的肺癌干细胞的荷瘤模型中CARL6-IL2M T细胞的抗肿瘤效果及增强CAR T细胞瘤体趋向和重塑肿瘤免疫微环境的作用机制，为靶向L6的CAR T细胞治疗肺癌提供实验依据。

Cancer stem cells are involved in resistance to chemotherapy and radiation therapy. It is probably an effective approach to cure solid tumor through CART targeting cancer stem cells. However, how to improve CAR T cells tumor tropism and intratumoral proliferation is a key issue to be solved. Our research team has been engaged in cancer stem cell and CAR T research for long time, and successfully found a novel high effective while low toxic IL-2 mutant by amino acid replacment, which has been shown to enhance T cell tumor tropism and enhance NK cell killing tumor function and improve anti-tumor effect. Our previous work has shown that small molecule compound-induced tumor stem cells increase the expression of TM4SF1 (L6). In this project, L6 was used as a therapeutic target for CAR T cells, and CARL6-IL2M T cells capable of autocrine IL-2 mutein were constructed using ICOS-4-1BB as a co-stimulatory CAR structure to study the effects of CAR L6-IL2M T cells on phenotype, migration, amplification and tumor killing function in vitro. We will further investigate the anti-tumor effect of CARL6-IL2M T cells and the mechanism of remodeling the tumor immune microenvironment in the cancer stem cell induced tumor model constructed on NSG mice and B57 mice. The project will provide experimental basis for the immunotherapy targeting lung cancer stem cells through L6 CAR T cells.