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Updated: Dec 1, 2025
Author Spotlight: Enhancing CAR-T Cell Function in Syngeneic Tumor Models
Published on: February 2, 2024
Optimized gene engineering of murine CAR-T cells reveals the beneficial effects of IL-15 coexpression
Evripidis Lanitis1, Giorgia Rota1, Paris Kosti1
1Department of Oncology, Ludwig Institute for Cancer Research Lausanne, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
Abstract:
Limited clinical benefit has been demonstrated for chimeric antigen receptor (CAR) therapy of solid tumors, but coengineering strategies to generate so-called fourth-generation (4G) CAR-T cells are advancing toward overcoming barriers in the tumor microenvironment (TME) for improved responses. In large part due to technical challenges, there are relatively few preclinical CAR therapy studies in immunocompetent, syngeneic tumor-bearing mice. Here, we describe optimized methods for the efficient retroviral transduction and expansion of murine T lymphocytes of a predominantly central memory T cell (TCM cell) phenotype. We present a bicistronic retroviral vector encoding both a tumor vasculature-targeted CAR and murine interleukin-15 (mIL-15), conferring enhanced effector functions, engraftment, tumor control, and TME reprogramming, including NK cell activation and reduced presence of M2 macrophages. The 4G-CAR-T cells coexpressing mIL-15 were further characterized by up-regulation of the antiapoptotic marker Bcl-2 and lower cell-surface expression of the inhibitory receptor PD-1. Overall, this work introduces robust tools for the development and evaluation of 4G-CAR-T cells in immunocompetent mice, an important step toward the acceleration of effective therapies reaching the clinic.
Insights
Fourth-generation CAR-T cells engineered with IL-15 show enhanced tumor control and TME reprogramming in mice. This study provides tools for developing better chimeric antigen receptor (CAR) T-cell therapies for solid tumors.
Area of Science:
- Immunology
- Oncology
- Biotechnology
Background:
- Chimeric antigen receptor (CAR) T-cell therapy shows limited clinical benefit in solid tumors.
- Overcoming the tumor microenvironment (TME) is crucial for improving CAR T-cell efficacy.
- Preclinical studies in immunocompetent mice are limited due to technical challenges.
Purpose of the Study:
- To develop and optimize methods for generating fourth-generation (4G) CAR-T cells in mice.
- To evaluate the efficacy of 4G CAR-T cells co-expressing murine interleukin-15 (mIL-15) in a preclinical model.
- To assess the impact of 4G CAR-T cells on the tumor microenvironment.
Main Methods:
- Optimized retroviral transduction and expansion of murine T lymphocytes.
- Development of a bicistronic retroviral vector encoding a tumor vasculature-targeted CAR and mIL-15.
- Characterization of 4G CAR-T cells in immunocompetent, syngeneic tumor-bearing mice.
Main Results:
- Efficient generation of central memory T cell (TCM)-phenotype murine T cells.
- 4G CAR-T cells co-expressing mIL-15 demonstrated enhanced effector functions, engraftment, and tumor control.
- TME reprogramming observed, including NK cell activation and reduced M2 macrophages.
- Upregulation of Bcl-2 and downregulation of PD-1 on 4G CAR-T cells.
Conclusions:
- This work provides robust tools for evaluating 4G CAR-T cells in immunocompetent mice.
- Co-engineering CAR-T cells with mIL-15 enhances anti-tumor activity and modifies the TME.
- These findings represent a significant step toward accelerating clinical translation of effective CAR T-cell therapies for solid tumors.
