CAR T-Cells Depend on the Coupling of NADH Oxidation with ATP Production

Area of Science:

• Immunology
• Metabolic Engineering
• Oncology

Background:

• Solid tumor microenvironments create metabolic challenges for chimeric antigen receptor (CAR) T-cell therapies.
• High lactate and hypoxia levels impede T-cell function by increasing NADH and depleting oxidized metabolites.

Purpose of the Study:

• To investigate whether Lactobacillus brevis NADH Oxidase (LbNOX) can enhance human CAR T-cell metabolic activity and antitumor efficacy.
• To assess the impact of LbNOX on CAR T-cells' response to metabolic stressors in vitro and in vivo.

Main Methods:

• Engineered CAR T-cells to express LbNOX, an enzyme that oxidizes NADH to NAD+.
• Assessed metabolic changes in LbNOX-expressing CAR T-cells, including oxygen and lactate consumption and pyruvate production.
• Evaluated the resilience of LbNOX-expressing CAR T-cells to lactate dehydrogenase inhibition.
• Tested the antitumor efficacy of LbNOX-expressing CAR T-cells in a mesothelioma mouse model.

Main Results:

• CAR T-cells engineered with LbNOX demonstrated increased oxygen and lactate consumption, along with enhanced pyruvate production.
• LbNOX expression conferred resilience to lactate dehydrogenase inhibition in CAR T-cells.
• In vivo studies using a mesothelioma model showed no significant improvement in antitumor efficacy for LbNOX-expressing CAR T-cells compared to controls.

Conclusions:

• While LbNOX can improve CAR T-cell metabolic function by managing NADH levels, it is insufficient to overcome the combined metabolic challenges of excessive NADH and insufficient ATP production in hostile tumor environments.
• The dual metabolic stressors in solid tumors necessitate strategies beyond simple NADH oxidation for effective CAR T-cell-mediated tumor clearance.