SynNotch-iNOS CAR-macrophages remodel the tumor immune microenvironment and exhibit antitumor efficacy via a CD4+ T cell-dependent mechanism

  • Transl Res. 2026 Jun 24:295:120-132. doi: 10.1016/j.trsl.2026.06.017.
Yuling Hong  1 ,  Buyun Dang  1 ,  Zhenqiong Zhou  1 ,  Cixin Liang  1 ,  Linying Li  1 ,  Qingxiang Gao  1 ,  Jia Zhang  1 ,  Shih-Chin Cheng  2
Affiliations
  • 1. State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian, 361102, China.
  • 2. State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian, 361102, China; Department of Gastroenterology, The National Key Clinical Specialty, School of Medicine, Zhongshan Hospital of Xiamen University, Xiamen University, Xiamen, 361004, Fujian Province, PR China; Radboud community for infectious diseases department of internal medicine, Radboud university medical center, 6500, HB, Nijmegen, The Netherlands. Electronic address: [email protected].
PMID: 42341916 DOI: 10.1016/j.trsl.2026.06.017
Abstract

Background: Chimeric antigen receptor T-cell (CAR-T) therapy shows limited efficacy against solid tumors due to the immunosuppressive tumor microenvironment (TME). Macrophages possess superior infiltration capabilities, yet their therapeutic potential remains under-realized.

Methods: We engineered a synNotch-iNOS CAR-macrophage (CAR iNOS-M) that releases nitric oxide (NO) upon CD19 recognition. Its efficacy was evaluated in syngeneic, immunocompetent murine models of metastatic melanoma.

Results: CAR iNOS-M therapy effectively reprogrammed the pulmonary tumor immune microenvironment (TIME), inducing potent antitumor responses independent of CD8+ T cells but strictly dependent on CD4+ T cells. Mechanistically, CAR iNOS-M treatment led to a significant reduction in pro-tumorigenic lung interstitial macrophages (IMs), subsequently decreasing Platelet Factor 4 (PF4) levels. This disruption of the PF4 signaling axis inhibited the polarization of immunosuppressive Th1-Tregs, alleviating T-cell exhaustion.

Conclusions: This study delineates a novel indirect mechanism for CAR-M, shifting the focus from direct phagocytosis to strategic TIME remodeling, providing a foundation for treating solid tumors.

Keywords
CAR-M; SynNotch-iNOS CAR-M; Tumor immune microenvironment.
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