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Updated: Jan 10, 2026
A Real-time Potency Assay for Chimeric Antigen Receptor T Cells Targeting Solid and Hematological Cancer Cells
Published on: November 12, 2019
Engineering TME-activated CD47-specific CAR macrophage via Arg1 promoter for safe and effective solid tumor
Fuyu Du1,2, Meixi Jiang1,2, Jingjing Qiu3
1School of Life Science and Technology, Xidian University, Xi'an, Shaanxi, People's Republic of China.
Background:
Chimeric antigen receptor macrophage (CAR-Mφ) therapy has promising therapeutic potential in solid tumors, yet challenges remain in target compatibility and systemic toxicity.
Methods:
In this study, we screened the CD47-scFv sequence of CAR-Mφ as the extracellular structure. We then constructed a classical CD47 CAR-Mφ incorporated the costimulatory domain of the α1β1 integrin-mediated Fc-gamma receptor I (FcγRI) signaling component. Subsequently, we developed a tumor microenvironment (TME)-responsive CAR macrophage platform by the arginase 1 (Arg1) promoter to target CD47, a highly expressed but clinically challenging immune checkpoint in solid tumors.
Results:
We found that anti-CD47-scFv-mediated macrophages can effectively kill tumor cells both in vivo and in vitro. Furthermore, by integrating an α1β1 integrin-mediated FcγRI signaling domain, CD47 CAR-Mφ exhibited superior antitumor activity in hCD47+4T1 and SGC-7901 cells in vitro, which demonstrated that the CD47 CAR-Mφ was effective against solid tumors. Subsequently, Arg1-mediated activated pArg1 CD47 CAR-Mφ exhibited strong cytotoxicity against target cancer cells. We further demonstrated TME-controllable CAR gene expression in situ and induced a significant regression of established tumors in vivo. Besides, TME-dependent activation of CD47 CAR Mφ reduced the cytotoxic killing effect on erythrocytes.
Conclusions:
Our findings confirmed that the TME-specific activation mechanism of pArg1 CD47 CAR-Mφ based on intrinsic Arg1 promoter reprogramming endowed CAR-Mφ to effectively mitigate erythrocyte toxicity while enabling safe multidose administration regimens. This Trojan horse-like CAR-Mφ system achieves tumor-specific activation while minimizing systemic toxicity, offering a novel strategy to expand CAR-Mφ applications for solid tumors.
