Abstract 1339: On-demand GLUT3 expression augments CAR-T cell metabolic fitness and antitumor efficacy while preventing toxicity in glioblastoma models.

Abstract The clinical success of chimeric antigen receptor T (CAR-T) cell therapy in hematologic malignancies has prompted its application to refractory solid tumors, including glioblastoma (GBM). However, CAR-T cell efficacy against solid tumors remains modest. Here, we demonstrate that the dysfunction of CAR-T cells in GBM is attributed to glucose deficiency in the tumor microenvironment (TME) and that on-demand, but not continuous, metabolic replenishment significantly improves the antitumor efficacy of CAR-T cells. Massive consumption of glucose by cancer cells reduces the glucose level in the TME of GBM, consequently impairing CAR-T cells. Modifying CAR-T cells with stable expression of GLUT3, a high-affinity glucose transporter restored their cytokine production and killing activity. However, while CAR-T cells with stable GLUT3 expression induced tumor reduction in a GBM model, their overactivation led to T-cell apoptosis, exhaustion, and terminal differentiation as well as adverse events and mouse death. On-demand GLUT3 CAR-T cells, in which GLUT3 transcription is driven by the nuclear translocation of nuclear factor of activated T-cells (NFAT) by target antigen stimulation, exhibit enhanced metabolic fitness and increased antitumor efficacy, leading to long-lasting tumor control in intracranial human GBM cell xenograft models while preventing adverse events. Cognitive dysfunction testing and histological analysis using a neuron damage marker, fluoro-Jade C (FJC), in mice treated with on-demand GLUT3 CAR-T cells did not show any signs of toxicity. We propose that on-demand, but not stable, metabolic fitness, such as at the time of exposure to tumor antigens, is a novel concept for maximizing the antitumor efficacy of CAR-T cells against solid tumors. Citation Format: Keisuke Watanabe, Jyunya Yamaguchi, Akihiro Nakamura, Yi-Tzu Lin, Kota Itahashi, Shohei Koyama, Daisuke Sugiyama, Shinichiro Kato, Akihito Nagata, Hitomi Nishinakamura, Yukihiro Shiraki, Atsushi Enomoto, Sachi Maeda, Fumiharu Ohka, Kazuya Motomura, Yuichiro Tsukada, Masaaki Ito, Yuka Maeda, Ryuzo Ueda, Atsushi Natsume, Ryuta Saito, Hiroyoshi Nishikawa. On-demand GLUT3 expression augments CAR-T cell metabolic fitness and antitumor efficacy while preventing toxicity in glioblastoma models abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1339.