A second-generation M1-polarized CAR macrophage with antitumor efficacy

DOI: 10.1038/s41590-023-01687-8Key Points:- Research focuses on using engineered macrophages (CAR-iMACs) instead of typical CAR T cells to fight solid tumors- Started with iPSCs (induced pluripotent stem cells) which were differentiated into macrophages and engineered with CARs- Created two versions: - First generation with CD3ζ domain - Second generation with added TIR domain- Second generation showed superior results due to TIR domain activating NFκB pathway- Testing showed complete tumor remission in liver cancer mouse modelsMechanisms:- TIR domain helps polarize macrophages to M1 (pro-inflammatory) state- Two-step killing process: 1. Induces apoptosis in tumor cells 2. Cleans up debris through efferocytosis- Confirmed mechanism through: - Single cell RNA sequencing - Time-lapse microscopy - NFκB pathway activation visualizationLimitations/Challenges:- Still preclinical (only tested in cells/mice)- CAR-iMACs don't survive long in body- Need more research before human trialsClinical Implications:- Promising for treating resistant solid tumors- Antigen-specific targeting means fewer side effects- Could be game-changing if survival time improved- Works well in combination with other treatments