Metabolic rewiring could help CAR-T cells fight solid tumors

By Vijay Kumar MalesuReviewed by Susha Cheriyedath, M.Sc.Apr 29 2026

By reshaping how engineered immune cells use glucose, fats, and amino acids, researchers hope to help CAR-T therapy survive the hostile metabolism of solid tumors.

Study: Metabolic reprogramming of CAR-T cells: a multi-pronged strategy to conquer the immunosuppressive tumor microenvironment. Image Credit: Corona Borealis Studio / Shutterstock

In a recent review published in the journal Cell Communication and Signaling, researchers in China evaluated how metabolic reprogramming may enhance the efficacy of chimeric antigen receptor T cells (CAR-T cells) in hostile tumor environments.

CAR-T Metabolism in Solid Tumor Environments

Why do some of the most advanced cancer therapies fail against solid tumors? Despite remarkable success in blood cancers, CAR-T cell treatment is much less effective against solid tumors due to the tumor microenvironment. This environment deprives immune cells of nutrients, disrupts metabolic pathways, and results in a buildup of toxic metabolites that can weaken the immune response. Solid tumor cells compete with CAR-T cells for glucose, lipids, and amino acids, leading to immune exhaustion and reduced therapeutic success.

Understanding how metabolism influences immune function is critical for improving cancer therapies. Further research is needed to develop strategies that enhance immune cell survival and effectiveness in metabolically hostile tumors.

Nutrient Competition and Tumor Metabolic Barriers

CAR-T cell therapy involves engineering T cells so that they can target and kill cancer cells. Yet, in solid tumors, these cells navigate a highly competitive, immunosuppressive environment. Tumor cells consume large amounts of glucose via glycolysis, reducing glucose availability for CAR-T cells and impairing their activation, proliferation, and cytotoxicity.

Secondly, toxic byproducts such as lactate and reactive oxygen species (ROS) are formed, further weakening immunity.

The additional stress from amino acid depletion and disrupted lipid metabolism can further reduce CAR-T cell function, persistence, and survival.

Glucose Reprogramming to Boost CAR-T Function

Glucose is the primary fuel for activated effector T cells. Enhancing glucose uptake and utilization is a key strategy to improve CAR-T cell performance. Metabolic priming controls the nutrients T cells receive during development, creating “memory-like" cells that persist longer in the body and rely more on mitochondrial metabolism and fatty acid oxidation.

Another important factor in this process is genetic modification. Increasing the expression of glucose transporters, such as Glucose Transporter Type 1 (GLUT1), enables CAR-T cells to take up more glucose, improving energy production and reducing exhaustion.

Advanced strategies use alternative transporters, such as Glucose Transporter Type 3 (GLUT3), which function better under low-glucose conditions, allowing CAR-T cells to survive even in nutrient-poor tumors.

Drugs can further support this process by targeting metabolic enzymes, improving mitochondrial function, boosting energy production, and reducing cellular stress. Examples discussed in the review include DCA, low-dose 2DG, enasidenib, PKM2 activation, and LDHA inhibition. Together, these methods may help keep CAR-T cells active, even when nutrient levels are low.

Lipid Metabolism and CAR-T Persistence

While glucose supports immediate activity, lipid metabolism is crucial for long-term survival and memory formation. CAR-T cells that rely on fatty acid oxidation (FAO) show better persistence and durability.

Selecting specific costimulatory domains during CAR design promotes lipid-based metabolism and enhances cell longevity. For example, 4-1BB-based CAR designs tend to support fatty acid oxidation and memory-like persistence, whereas CD28-based designs more strongly favor glycolytic effector activity.

Techniques such as FLASH (ultra-high-dose-rate) radiotherapy may alter the tumor microenvironment to reduce immunosuppressive signals and/or increase infiltration of CAR-T cells into the tumor. In preclinical medulloblastoma models, FLASH radiotherapy appeared to reprogram macrophage lipid metabolism, creating a less suppressive environment that improved GD2 CAR-T cell infiltration and activation.

In addition, combining agents that induce ferroptosis (a type of cell death driven by lipid metabolism) with CAR-T therapy provides a strategy to attack tumors. The cumulative effect of these advances could enhance the overall viability and efficacy of CAR-T cells when used against solid tumors.

Amino Acid Deprivation and Toxic Metabolite Strategies

Amino acids are essential for protein synthesis and immune signaling. Tumor cells consume key amino acids such as tryptophan and arginine, leaving CAR-T cells deprived, which leads to reduced proliferation and increased exhaustion.

Researchers have developed CAR-T cells that express amino acid transporters, enabling them to compete more effectively for these nutrients. In addition, new technologies for CAR-T cells may equip them with enzymes that help regenerate specific amino acids, such as arginine, making them less reliant on outside sources.

Another major problem with CAR-T therapy is the buildup of immunosuppressive substances, such as kynurenine, which decreases T cell function and helps maintain immune tolerance. One pharmacological approach is to inhibit IDO1, an enzyme that drives tryptophan depletion and kynurenine accumulation.

Researchers have also engineered CAR-T cells to express enzymes that degrade or eliminate toxic metabolites produced in the tumor area, thereby allowing the engineered CAR-T cells to neutralize the T cell suppression in that area.

Personalized Multi-Pathway CAR-T Metabolic Design

The metabolic profile of tumors varies widely between patients and cancer types. Future CAR-T therapies may be designed by combining multiple methods that target glucose, lipids, and amino acids to create personalized metabolic modifications tailored to each patient's tumor environment.

In addition to using a combination of different methods targeting different pathways, researchers are also developing dynamic and controlled systems that will allow for metabolic enhancements to be activated within the tumor environment alone, minimizing the potential for side effects. This is important because continuous overexpression of some metabolic genes could raise long-term safety concerns.

This evolution is shifting from using single-target therapies to using integrated, adaptable therapies. By enhancing the metabolic flexibility of CAR-T cells, they may gain greater tolerance to the hostile environment of solid tumors and potentially deliver more sustained therapeutic results.

Future Potential of Metabolically Enhanced CAR-T Cells

Metabolic reprogramming has emerged as a critical strategy to enhance the effectiveness of CAR-T cell therapy in solid tumors. By optimizing the use of both lipid and glucose and addressing amino acid deprivation in the tumor microenvironment, these approaches may help generate more durable and effective CAR-T cell therapies, although further clinical validation is needed.

Through a combination of genetic modifications, pharmacological interventions, and manufacturing advancements, it is possible to develop CAR-T cells with increased persistence, functionality, and tumor-killing capability.

Importantly, integrating multi-pathway and personalized strategies may further improve clinical outcomes. However, many of these approaches remain experimental and have been tested mainly in laboratory or animal models. 

Further research is needed to determine which strategies can safely enhance immune cell survival and effectiveness in metabolically hostile tumors.

These advances highlight the potential of metabolically enhanced CAR-T cells to help advance cancer treatment and extend their success beyond hematologic malignancies into more challenging solid tumors.

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