Chimeric Antigen Receptor Macrophages In The Treatment Of Tumors

ObjectiveImmune cell therapy is considered to be the most promising and rapidly developing treatment technology in the field of anti-tumor,especially CAR-T cell therapy.Although CAR-T cell therapy has achieved significant efficacy in hematological malignancies,its application in solid tumors is still extremely challenging.Similar to T cells,macrophages,as a kind of immune cell with powerful phagocytic function,also have the potential to kill tumor cells.This suggests that if we can effectively utilize the potential of macrophages,it will hopefully provide new ideas for the research of immune cell therapy technology,especially in the treatment of solid tumors.This thesis intends to use CAR technology to transform macrophages to explore the possibility of chimeric antigen receptor macrophages(CAR-Mφ)as a new type of anti-tumor therapy.MethodsIn order to conceptually explore the possibility of applying CAR technology to macrophages to fight tumors,We will learn from the mature CAR structure of CAR-T,and use CD19-CAR as the extracellular segment,the transmembrane region of the CD8 molecule and the intracellular activation motifs of different receptors as the intracellular domains to construct different candidate CAR molecules;Detect the in vitro tumor phagocytic ability of macrophages modified by different CAR molecules by flow cytometry;And test its anti-tumor effect in combination with small molecule drugs;At the same time,try to combine CAR-T with macrophages modified by CAR molecules for tumor treatment,and observe whether the two have a synergistic effect.ResultsThe three constructed CD19 CAR plasmids can all be expressed on the surface of mouse BMDM cells,and more obvious phagocytosis/killing effects can be seen in in vitro experiments;In in vitro experiments,when the small molecule drug manganese chloride is combined with CAR-BMDM,a more obvious enhancement effect can be seen;In in vitro experiments,the combination of CAR-BMDM and mouse CAR-T has obvious synergistic effect.The use of Ad5F35 adenovirus can transfect NKG2 D CAR into human primary macrophages to enhance its killing effect on NKG2 D ligand-positive tumor cells,but no significant synergistic effect has been observed in the combination with NKG2 D CAR-T.ConclusionsIt is feasible to make macrophages express CAR molecules to become effector cells with tumor-targeted killing function;Fc R-gamma,as the intracellular domain of CAR-M,has a good effect of killing tumor cells;Manganese ions can enhance the effect of CAR-M in killing tumor cells;In the mouse system,CAR-M can synergize the killing effect of CAR-T on tumor cells.The effectiveness of CAR molecules expressed by macrophages as a new anti-tumor therapy needs to be further verified.