Galunisertib enhances chimeric antigen receptor-modified T cell function.

Area of Science:

• Immunology
• Oncology
• Pharmacology

Background:

• Solid tumors create an immunosuppressive tumor microenvironment, hindering effective chimeric antigen receptor (CAR) T cell therapy.
• Transforming growth factor-beta (TGF-β) is a key mediator of this immunosuppression, enabling tumor immune evasion.

Purpose of the Study:

• To investigate if Galunisertib, a small molecule inhibitor of TGF-β receptor I, can enhance the efficacy of CAR T cell therapy against solid tumors.
• To evaluate the impact of Galunisertib on CAR T cell function, including cytotoxicity and cytokine production, in the context of solid tumor treatment.

Main Methods:

• In vitro experiments were conducted using CD133- and HER2-specific CAR T cells co-cultured with solid tumor cells.
• The effects of Galunisertib on CAR T cell cytotoxicity, cytokine secretion, proliferation, and activation markers (CD69) were assessed.
• TGF-β levels secreted by T cells and TGF-β signaling within CAR T cells were measured.

Main Results:

• Galunisertib significantly enhanced the specific cytotoxicity of both CD133- and HER2-specific CAR T cells against target tumor cells.
• Galunisertib treatment led to increased cytokine secretion from CAR T cells and non-transfected T cells, without directly killing tumor cells.
• The inhibitor reduced TGF-β signaling in CAR T cells, which were found to secrete TGF-β upon activation.

Conclusions:

• Galunisertib effectively enhances CAR T cell function against solid tumors by counteracting TGF-β-mediated immunosuppression.
• The combination of Galunisertib and CAR T cells presents a promising strategy for improving solid tumor treatment outcomes.
• Further preclinical and clinical studies are warranted to validate this therapeutic approach.