Addressing unmet needs for CAR T cell efficacy in solid tumors, Hirabayashi, Du et al. designed a novel two-construct CAR T, with each construct targeting a distinct antigen and containing either aCD28 or 4-1BB costimulatory domain; only one carried a “shared” CD3ζ. In a neuroblastoma model, the dual CAR was efficacious under stress conditions, protected against rechallenge, and prevented tumor escape due to heterogenous antigen expression. RNAseq revealed a metabolic profile of CAR T cell proliferation undergoing glycolytic and oxidative metabolism, consistent with rapid effector T cell activity and long-term survival. The approach was validated using a second pair of targets.
Contributed by Katherine Turner
ABSTRACT: Chimeric antigen receptor (CAR)-T cells showed great activity in hematologic malignancies. However, heterogeneous antigen expression in tumor cells and suboptimal CAR-T-cell persistence remain critical aspects to achieve clinical responses in patients with solid tumors. Here we show that CAR-T cells targeting simultaneously two tumor-associated antigens and providing trans-acting CD28 and 4-1BB co-stimulation, while sharing the same CD3ζ-chain cause rapid antitumor effects in in vivo stress conditions, protection from tumor re-challenge and prevention of tumor escape due to low antigen density. Molecular and signaling studies indicate that T cells engineered with the proposed CAR design demonstrate sustained phosphorylation of T-cell-receptor-associated signaling molecules and a molecular signature supporting CAR-T-cell proliferation and long-term survival. Furthermore, metabolic profiling of CAR-T cells displayed induction of glycolysis that sustains rapid effector T-cell function, but also preservation of oxidative functions, which are critical for T-cell long-term persistence.
