Purpose. Chimeric antigen receptor (CAR) T cell therapy has emerged as a promising cancer treatment. Nevertheless, the tumor microenvironment (TME) of solid tumors provides substantial challenges to CAR T cells efficacy. Tumor growth factor-beta (TGF-β), a potent immunosuppressive cytokine in the TME, impedes T cell activation, proliferation, and cytotoxicity, diminishing the anti-tumor potency of CAR T cells. This study investigates whether TGF-β CAR T cells can overcome these barriers and remain functional in TGF-β-rich environments. Methods. We developed a novel TGF-β CAR T cell (TGF-βRII-CD28CD3z) and a dominant-negative TGF-β receptor (dnTβRII) T cell utilizing Jurkat cells. Transduction efficiency and surface expression were confirmed using flow cytometry. T cell activation and proliferation were assessed by CD69 and Ki-67 expression, respectively. IL2 and IFN-γ secretion were quantified using ELISA kits. Results. Flow cytometry confirmed the successful cell surface expression of the designed receptors; 62% and 24% for TGF-β CAR and dnTβRII respectively. TGF-β CAR T cells were markedly activated in a dose-dependent manner, with optimal responses at 10 ng/ml TGF-β, and sustained proliferation (92%) and cytokine production (e.g., 110 pg/ml ± 10.7 IL2 and 94.3 pg/ml ± 10.2 IFN-γ) even at 5 ng/ml TGF-β. In contrast, dnTβRII T cells exhibited partial resistance via IL2 production but failed to sustain proliferation or IFN-γ production. The TGF-β CAR T cells effectively resisted TGF-β-mediated suppression, highlighting their functional advantage. Conclusions. Our finding demonstrate that the TGF-β CAR T cells not only resist TGF-β-mediated suppression but also promote activation, proliferation and proinflammatory cytokine release in presence of TGF-β. This underscores their therapeutic potential as an innovative approach to overcome TGF-β-driven immunosuppression and improve the CAR T cell therapy efficacy in solid tumors.
Mansoori et al. (Sat,) studied this question.