Glutamic-oxaloacetic transaminase 2 (GOT2) as a dual-functional enhancer for CAR-T cell metabolic fitness

CAR-T cell therapy has transformed the treatment landscape for hematologic malignancies, yet its efficacy in solid tumors remains challenged. Aspartate is one of the most critically depleted metabolites in the solid tumor microenvironment; its deficiency impairs T cell proliferation, redox balance, and mitochondrial fitness. GOT2, a mitochondrial enzyme in the malate-aspartate shuttle, plays a critical role in T cell metabolism, as it catalyzes the conversion of oxaloacetate to aspartate. In doing so, GOT2 also helps maintain redox balance and energy production. In addition to its canonical role in aspartate biosynthesis, recent studies in cancer cells suggest that GOT2 regulates fatty acid metabolism through the activation of the transcription factor PPARdelta. In T cells, PPARdelta is shown to regulate the formation of central memory phenotype and long-term survival. In this study, we examined whether GOT2 overexpression enhances CAR-T cell metabolic fitness and antitumor activity. We found that GOT2-overexpressing CAR-T cells (CART19-GOT2) exhibit superior cytolytic function in both in vitro hypoxic conditions and in vivo tumor models. In xenograft models of NALM6 leukemia, CART19-GOT2 was able to sustain tumor control and prevented regrowth even after rechallenge. Compared to standard CART19 cells, CART19-GOT2 show enhanced mitochondrial respiration and spare respiratory capacity, indicating better mitochondrial fitness. GOT2 overexpression also elevated intracellular aspartate levels in CAR-T cells in normal growth conditions and under hypoxic stress. Using isotypically labeled nutrients as tracers, we found that aspartate is replenished through a cooperative interplay of fuels in primary human T cells, with glutamine serving as the preferred substrate. Collectively, these findings indicate that GOT2 overexpression is a promising strategy for metabolic enhancement of CAR-T cells for solid tumor immunotherapy.