CD47-CCR/CAR-T细胞系的建立及其在肺癌干细胞免疫逃逸中的作用和机制的研究

Our previous work and the latest international research have proved that CD47 is expressed at even higher levels on tumor stem cells than their normal counterparts. Higher expression levels of CD47 on human tumor stem cells contribute to pathogenesis by inhibiting macrophages phagocytosis through the interaction of CD47 with an inhibitory receptor SIRP-alpha on macrophages, and by inhibiting T cells killing through the interaction of CD47 with an inhibitory receptor TSP-1 on T cells. So, tumor stem cells evade the immune surveillance and killing effect, and create conditions for their further proliferation, invasion and metastasis. On the basis of our previous work, this project is to construct the CD47 monoclonal antibody variable region double chimeric antigen receptor (CD47-CCR/CAR) in vitro. We first set up a unique cell line, CD47-CCR/CAR double modified T cell (CD47-CCR/CAR-T), in the world. This cell line can combinate the effect of CD47 monoclonal antibody breaking the immune tolerance state of tumor microenvironment and the effect of further enhance the T cell self killing ability. We take the lung cancer stem cells as the research object and clarify that CD47-CCR/CAR-T cells can break the immune tolerance of tumor microenvironment, recover the phagocytosis of macrophages, and further enhance the cytotoxicity of T cells, while minimize the injury to normal tissues, through in vitro and in vivo experiments using living cells workstation and living animal imaging and other research methods. This project can reveal the role of CD47-CCR/CAR-T cells in inhibiting the immune escape of lung cancer stem cells, and provide an innovative rationale and clinical basis for CD47-CCR/CAR-T as an immune cell target for the treatment of cancer stem cells.

我们前期工作和国际最新研究证实：肿瘤干细胞能通过高表达CD47来抑制巨噬细胞的吞噬功能和T细胞的杀伤作用，从而逃避机体免疫监视作用，为自身进一步增殖、浸润和转移创造条件。本课题是在我们前期工作基础上，体外构建CD47单克隆抗体可变区双重修饰的嵌合型抗原受体(CD47-CCR/CAR)，在国际上率先建立起能将CD47单抗打破肿瘤微环境免疫耐受状态和进一步提高自身杀伤能力进行强强联合的CD47-CCR/CAR双重修饰的T细胞系(CD47-CCR/CAR-T)；以肺癌干细胞为研究对象，通过细胞体外和小鼠体内实验，阐明CD47-CCR/CAR-T细胞能打破肿瘤微环境免疫耐受状态，恢复巨噬细胞的吞噬作用、进一步提高T细胞的杀伤功能；从而揭示CD47-CCR/CAR-T细胞在抑制肺癌干细胞免疫逃逸机制中的作用，为CD47-CCR/CAR-T可成为免疫细胞靶向治疗肿瘤干细胞提供创新性的理基础和临床依据。