On November 11, 2020, Zhang Jin’s team from the Stem Cell and Regenerative Medicine Center of Zhejiang University School of Basic Medicine/Zhejiang Liangzhu Laboratory, Weng Qinjie’s team from the School of Pharmacy of Zhejiang University and the Huanghe team of the First Affiliated Hospital of Zhejiang University jointly presented the Journal of Hematology & Oncology (IF: 11.059) published an article titled Pluripotent Stem Cell-derived CAR-Macrophage Cells with Antigen-dependent Anti-Cancer Cell Functions, the first report of expression chimerism based on induced pluripotent stem cell (iPSC) differentiation Application of antigen receptor macrophages (CAR-iMac) in immune cell therapy of tumors.
Chimeric antigen receptor T cell immunotherapy (CAR-T therapy) is a new type of cellular immunotherapy technology that has developed very rapidly in recent years. It has a very significant therapeutic effect in tumor treatment, especially certain hematological tumors. However, this therapy also has many challenges, including the difficulty of T cells infiltrating solid tumors, being inhibited and depleted in the complex tumor microenvironment, the efficiency of gene modification of primary T cells is limited and the obtained cells have high heterogeneity , And the high cost due to the personalized manufacturing process . In order to overcome these obstacles, researchers have adopted various strategies, including optimizing chimeric antigen receptors, improving the function of T cells, optimizing the proportion of T cell subsets or using other types of immune cells [2-3], and making "off-the-shelf" universal T cells etc.
In this study, researchers from Zhejiang University developed CAR-expressing iPSC-derived Macrophage (CAR-iMac) derived from iPSC differentiation of induced pluripotent stem cells for tumor immune cell therapy. Induced pluripotent stem cells (iPSC) are produced by reprogramming of human peripheral blood mononuclear cells and have the potential to differentiate into a variety of somatic cells. Because they come from the patient itself, they are easy to expand, and have monoclonal genetic modifications. /Editing convenience and other advantages have received widespread attention and have been rapidly developed in recent years. One of the important applications is differentiation into immune cells. Previous studies reported that CAR-T and CAR-NK cells were derived from iPSC differentiation [4-5], which have good killing effects on hematoma and solid tumors.
In this study, using the above characteristics of iPSC, the CAR-iMac cells obtained not only have high yield (>50x) and purity (close to 100% CD11b/CD14 positive), but also have the gene expression profile of macrophages and mature macrophages. The functions of phagocytosis and polarization of cells. The single-cell transcriptome sequencing analysis and pseudo-time analysis of the differentiation products showed that the differentiation path was from pluripotent stem cells to hematopoietic stem progenitor cells, and then to macrophages and DC cells. When co-cultured with lymphoma cells expressing CD19 antigen or ovarian cancer cells expressing mesothelin antigen, CAR-iMac cells exhibit antigen-dependent phagocytosis and tumor-killing functions, as well as antigen-dependent secretion to promote inflammation and suppress tumors. Cytokines and the function of polarization to M1 type macrophages. CAR-iMac cells also exhibit the ability to inhibit tumor cell growth in hematological tumors and solid tumor models in mice. This research provides new ideas and broad application prospects for tumor cell immunotherapy.
At present, CAR-T, CAR-NK, and CAR-M derived from human iPSC have come out one after another, and they are gradually transforming into clinical practice. Among them, iPSC CAR-NK cells have started clinical trials in B-cell lymphoma and chronic lymphocytic leukemia. I believe that more iPSC-derived immune cells will have broad application prospects in tumor immune cell therapy in the future.
Doctoral student Zhang Li and postdoctoral fellows Tian Lin and Yu Hua of School of Basic Medical Sciences, as well as Dai Xiaoyang and doctoral student Wang Jiajia from the School of Pharmacy are the co-first authors of the article. Researcher Zhang Jin, Professor Huang He and Associate Professor Weng Qinjie are the corresponding authors of this article. This project is supported by the Ministry of Science and Technology Key R&D Program Project, National Natural Science Foundation of China, Zhejiang Natural Science Foundation, Zhejiang Innovation Team, and Zhejiang Laboratory of Systems Medicine and Precision Diagnosis (Liangzhu Laboratory), Zhejiang University Medical Center and Supported by the Institute of Blood Research, Zhejiang University.
1. June CH & Sadelain M, Chimeric Antigen Receptor Therapy. The New England journal of medicine 379, 64-73 (2018).
2. Klichinsky M, et al., Human chimeric antig
On March 18, 2021, Carisma Therapeutics of the United States (hereinafter referred to as Carisma) announced the completion of the first patient administration of CAR-M therapy (CT-0508) targeting Her2, marking CAR-M transformation for the treatment of solid tumors Enter a new era.
In recent years, the engineering of CAR innate immune cells has received widespread attention. Among them, CAR-modified macrophages (CAR-Mac) are considered to be a cell type that is expected to overcome the limitations of CAR-T therapy and has a promising future in conquering solid tumors.
Macrophage mechanism of action
Macrophages activate lymphatic or other immune cells by engulfing cell debris and pathogens in body fluids and tissues and presenting antigens to make them respond to pathogens. In the tumor microenvironment, macrophages are the innate immune cells with the highest infiltration rate and can interact with almost all cellular components in TME, stimulate angiogenesis, increase tumor invasion, and mediate immunosuppression (1).
Tumor-associated macrophages (tumor-associated macrophage, TAM) are widely present in the microenvironment of solid tumors (tumor microenvironment, TME), and have important functions such as phagocytosis and killing of pathogens, processing and presentation of antigens. After activated, M1 type macrophages have a strong antigen-presenting ability and secrete reactive oxygen species (ROS) and pro-inflammatory cytokines, which are associated with a good prognosis of cancer (2).
Difficulties of engineered macrophage technology
(1) Macrophages are the first responders to viral infections in the human body and have a strong efflux effect on viruses, making it difficult for macrophages to be transfected by standard viral vectors used in gene therapy and cell therapy.
(2) The ability of primary macrophages to expand in vitro is weak in vitro.
Pre-clinical research data show promising prospects
Carisma's preclinical research results show that CAR-Mac exhibits antigen-specific phagocytosis and tumor killing effects in in vitro experiments. It is not only effective on target-positive tumor cells, but also has a certain killing effect on target-negative tumor cells. It is functionally similar to the original Tumor vaccine. In solid tumor xenograft mouse models, a single injection of CAR-Mac can significantly reduce tumor burden and prolong overall survival (fig 1). In humanized mouse model experiments, CAR-Mac can induce the production of pro-inflammatory tumor microenvironment and enhance the activity of anti-tumor T cells. In the presence of immunosuppressive cells, CAR-Mac can still kill tumors. Further analysis of the cell viability characterization results showed that CAR-M can express pro-inflammatory cytokines and chemokines, convert M2 type macrophages to M1 type, up-regulate the antigen presentation mechanism, recruit antigens and present them to T cells , While resisting the role of immunosuppressive cytokines (3).
Fig1. A: CAR-M treated mice demonstrated a marked reduction in tumor burden; B: CAR-Ms conferred a prolongation of overall survival.
1. Chen Y, Yu Z,Tan X, Jiang H, Xu Z, Fang Y, et al. CAR-macrophage: A newimmunotherapy candidate against solid tumors. Biomed Pharmacother.2021;139:111605.
2. Jayasingam SD, CitartanM, Thang TH, Mat Zin AA, Ang KC, Ch'ng ES. Evaluating the Polarization ofTumor-Associated Macrophages Into M1 and M2 Phenotypes in Human Cancer Tissue:Technicalities and Challenges in Routine Clinical Practice. Front Oncol.2019;9:1512.
3. Klichinsky M, Ruella M,Shestova O, Lu XM, Best A, Zeeman M, et al. Human chimeric antigen receptormacrophages for cancer immunotherapy. Nat Biotechnol. 2020;38(8):947-53.