Solid-tumor CAR-Ts face suppression from tumor-associated cells—macrophages, MDSCs, CAFs, and regulatory T cells—that compete for nutrients and secrete immunosuppressive metabolites such as arginase, adenosine, and lactate.

The hostile tumor microenvironment in solid tumors imposes metabolic stress—glucose deprivation, hypoxia, acidosis, lactate buildup, adenosine, and amino acid depletion—that drives CAR-T exhaustion and dysfunction.

Researchers advocate pharmacologic and genetic strategies to favor central memory formation and long-term CAR-T persistence, including targeting NR4A factors, BATF, mTOR and AMPK signaling, and possibly using rapamycin during manufacturing.

A unified model emphasizes pairing intrinsic CAR-T engineering with extracellular environment modulation, while acknowledging translation challenges from mouse models to humans, manufacturing limits, and safety concerns such as cytokine release syndrome and neurotoxicity.

Metabolic engineering approaches include overexpressing glucose transporters (GLUT1/GLUT3), boosting mitochondrial metabolism (pyruvate carrier, CPT1A), and adjusting transcriptional regulators (FOXO1, PGC-1α) to foster memory-like states and resist exhaustion.

Targeting additional vulnerabilities like ferroptosis resistance (GPX4), amino acid transport (SLC7A5), and modulating GCN2-ATF4 pathways can help CAR-T cells endure nutrient scarcity.

A patient-specific, metabolically informed strategy could tailor intrinsic CAR-T design and extrinsic microenvironment interventions to extend solid-tumor efficacy beyond what’s observed in liquid cancers.

Emerging view that CAR-T metabolic fitness—not just receptor design—largely determines success in solid tumors by shaping differentiation, persistence, and exhaustion trajectories.

Metabolic-epigenetic links, such as SAM and α-ketoglutarate influencing chromatin states, may govern exhaustion-related gene silencing and CAR-T fate through epigenetic metabolism.

Beyond intrinsic rewiring, the roadmap includes extrinsic strategies: depleting suppressive metabolites (IDO1, adenosine pathways), reprogramming tumor stroma and immune cells, and creating hypoxia-responsive CAR-Ts to localize activity within tumors.

T-cell metabolism evolves through activation: naive T cells rely on oxidative phosphorylation, activated T cells shift to aerobic glycolysis for growth, and memory-like T cells depend on fatty acid oxidation and robust mitochondrial health to persist.