Pleiotropic oxidized carbon nanozymes reprogram CAR T cell metabolism to enhance persistence through redox modulation

Adoptive CAR T cell therapy faces major challenges in solid tumors due to chronic antigen stimulation, oxidative stress, and metabolic exhaustion. We recently developed Pleozymes, pleiotropic oxidized carbon nanozymes that function as synthetic redox mediators with multiple enzymatic activities, including superoxide dismutase-like scavenging and NADH/NAD⁺ interconversion. Pleozymes are 3-8 nm oxidized carbon nanoparticles synthesized from coconut-derived activated charcoal and exhibit broad redox potential and mitochondrial localization, enhancing both oxidative phosphorylation and glycolysis in mammalian cells. To investigate their role in T cell metabolic resilience, we treated GPC3-targeted CAR T cells with Pleozymes during chronic co-culture with GPC3-positive HCC Huh7 cells over repeated stimulation cycles. Cell proliferation, apoptosis, exhaustion marker expression, and memory subset differentiation were assessed by flow cytometry and metabolic assays. Pleozymes markedly enhanced CAR T cell expansion and viability across repeated tumor challenges. Apoptotic rates were reduced, and expression of exhaustion markers TIM-3 and LAG-3 decreased significantly. Pleozymes promoted differentiation toward T stem cell memory (TSCM) and central memory (TCM) phenotypes, indicating improved persistence potential. Metabolic profiling indicated elevated total ATP levels and enhanced NAD⁺-dependent catabolic activity, consistent with concurrent activation of glycolysis, fatty acid beta-oxidation, and tricarboxylic acid (TCA) cycle flux. Collectively, these findings demonstrate that Pleozymes act as metabolic cofactors that restore redox balance and sustain bioenergetic flexibility in CAR T cells. By mitigating exhaustion and enhancing memory differentiation, Pleozymes offer a novel, non-genetic strategy to improve CAR T cell persistence and antitumor efficacy in solid tumor settings.