The challenge of targeting solid tumors with immune-based therapies has long been hampered by a metabolic tug-of-war, where cancer cells voraciously consume glucose, depriving tumor-infiltrating lymphocytes (TILs) of the vital energy substrate required for their function. T cells rely heavily on glucose to fuel their proliferation, cytokine production, and cytotoxicity. When glucose availability plummets in the nutrient-deprived tumor milieu, immune cells become energetically starved, subsequently diminishing their capacity to mount effective anti-tumor responses. This metabolic constraint is a major barrier to successful immunotherapy in solid tumors, allowing cancer cells to evade immune eradication.

To circumvent this metabolic impasse, the UCLA research team ingeniously turned to cellobiose, a disaccharide sugar that is naturally abundant in plant fibers but is metabolically inaccessible to human and tumor cells. Unlike glucose, cellobiose is not absorbed or utilized by mammalian cells or cancer cells, which renders it an ideal exclusive nutrient source to “outsmart” the tumor’s competitive metabolism. Critically, cellobiose is regarded as safe by the U.S. FDA and is already commonly incorporated into various food products, emphasizing its translational potential for clinical applications.

Capitalizing on microbial metabolic pathways, the researchers genetically engineered T cells to express two fungal-derived proteins that enable these cells to import cellobiose and enzymatically convert it intracellularly into glucose. This creative bioengineering provides these T cells an exclusive, tumor-resistant energy supply, effectively bypassing the glucose scarcity imposed by the tumor microenvironment. By appropriating a unique metabolic pathway foreign to mammalian biology, the engineered T cells gain a considerable metabolic advantage in nutrient competition with cancer cells.

In rigorous in vitro experiments designed to simulate the harsh, glucose-depleted conditions present inside solid tumors, the cellobiose-metabolizing T cells demonstrated remarkable metabolic resilience. They maintained cellular viability, sustained proliferation, and robust cytokine production—including key anti-cancer cytokines interferon-gamma (IFN-γ) and tumor necrosis factor (TNF). In stark contrast, unmodified T cells rapidly lost function and succumbed under these nutrient-starved conditions, underscoring the transformative potential of the engineered metabolic adaptation.

Progressing to preclinical mouse models, the enhanced T cells were deployed against established solid tumors. Treatment with the engineered immune cells led to significantly delayed tumor progression and extended survival relative to control groups receiving conventional T cell therapy. Intriguingly, a subset of treated mice exhibited complete tumor regression, highlighting the potent therapeutic promise of this metabolic engineering approach for solid malignancies.

Immunophenotyping within the tumor microenvironment provided further insights; the engineered T cells exhibited heightened activity, increased proliferation, and an improved immunological phenotype characterized by reduced signs of exhaustion. Immune exhaustion, a dysfunctional state marked by decreased effector function and sustained expression of inhibitory receptors, has been a formidable obstacle limiting the efficacy of adoptive cell therapies in cancer. This metabolic strategy, therefore, not only fuels T cell function but may also counteract exhaustion, restoring potent anti-tumor immunity.

A key author of the study, Dr. Matthew Miller, who conducted this research during his doctoral training and now continues as a postdoctoral fellow at the Salk Institute, emphasized that their findings definitively demonstrate how glucose availability is a critical determinant of effective T cell-mediated tumor control. By deploying a proprietary metabolic processing system, immune cells can be selectively provisioned with a nutrient shielded from tumor exploitation, fundamentally altering the battle for metabolic resources in the tumor microenvironment.

Beyond murine models, this intervention was also tested using human CAR-T cells, which have revolutionized the treatment of hematologic cancers but have faced significant hurdles in solid tumor settings. Under physiologically relevant glucose-deprived conditions mimicry in vitro, cellobiose supplementation restored CAR-T cell survival, proliferative capacity, cytokine secretion, and cytotoxic function. In vivo mouse studies further reinforced that CAR-T cells metabolically reprogrammed to utilize cellobiose infiltrated tumors with enhanced vitality and demonstrated promising anti-tumor efficacy.

Senior author Dr. Manish Butte, a distinguished immunologist and oncologist at UCLA, remarked on the remarkable metabolic fitness conferred to the modified T cells. “In the absence of glucose, these T cells engaged cellobiose to power essential metabolic pathways ordinarily dependent on glucose, exhibiting a metabolically healthy phenotype rather than starvation,” he explained. This observation underscores a profound metabolic flexibility elicited by the fungal proteins, enabling immune cells to transcend a fundamental limitation imposed by tumor metabolism.

Importantly, the researchers underscore the broad applicability of this technology across myriad T cell-based immunotherapies, as over 500 ongoing clinical trials worldwide are exploring CAR-T and related treatments for solid tumors—many hampered by immune exhaustion and metabolic failure. The incorporation of these two fungal genes, coupled with controlled systemic delivery of cellobiose, holds promise to universally amplify the efficacy of T cell therapies by overcoming one of the most intractable barriers to solid tumor immunotherapy success.

The team’s multidisciplinary approach, bridging immunology, cancer biology, and metabolic engineering, heralds a new era of metabolic innovation in cancer treatment. Leveraging a naturally abundant, non-toxic sugar inaccessible to cancer cells, they have devised a strategy that effectively grants immune cells a “metabolic sanctuary” within the hostile tumor microenvironment. The potential impact of this research extends far beyond preclinical models, foreshadowing translational applications that could reshape therapeutic paradigms for some of the deadliest solid tumors.

This research was generously supported by esteemed grants from the National Institutes of Health, the E. Richard Stiehm Endowment, the Natasha and Brandon Beck Foundation, and fellowships associated with the UCLA Jonsson Comprehensive Cancer Center. The full scientific report is published in the premier journal Cell (DOI: 10.1016/j.cell.2026.01.015), offering the global biomedical community a detailed description of this visionary metabolic engineering feat.

Moving forward, clinical translation efforts will focus on incorporating this cellobiose metabolism module into next-generation CAR-T cells and other adoptive T cell therapies for solid tumors. Further studies to optimize the delivery and dosing of cellobiose and confirm safety in humans will be paramount. If successful, this innovation may finally unlock the full power of immunotherapy against resistant solid tumors that have thus far defied curative treatment.

This novel metabolic intervention represents an elegant example of bioengineering ingenuity meeting urgent clinical need, illuminating a promising path forward in the war against cancer by fortifying the soldiers of the immune system with an unassailable energy fuel source beyond the reach of their adversaries.

Subject of Research: Cancer immunotherapy, T cell metabolism, CAR-T therapy, solid tumors

Article Title: Tumor-Resistant Sugar Metabolism Enhances T Cell Immunotherapy in Solid Cancers

News Publication Date: 2026

Web References:

• https://www.cell.com/cell/fulltext/S0092-8674(26)00102-9
• http://dx.doi.org/10.1016/j.cell.2026.01.015

Keywords:
Chimeric antigen receptor therapy, Cancer immunology, Cancer immunotherapy, Cancer, Immunology, Cancer research

Immunotherapy, especially CAR-T cell therapy, has revolutionized treatments for blood cancers like leukemia and lymphoma by genetically modifying patients’ T cells to recognize and attack cancer cells. However, extending these successes to solid tumors has been challenging due to the complex microenvironment and heterogeneity of these cancers. Solid tumors develop dense stromal barriers that immune cells struggle to penetrate, and they frequently display diverse antigenic profiles that allow malignant cells to evade immune detection. The structural sophistication of these tumors, coupled with their immune evasion strategies, has posed formidable obstacles for conventional CAR-T therapies.

Unlike CAR-T cells, engineered CAR-NKT cells leverage the innate tumor-homing properties of NKT cells, enabling them to traverse the physical and immunosuppressive barriers that characterize solid tumors. NKT cells uniquely combine features of both innate and adaptive immunity, allowing them to rapidly respond to tumor antigens and secrete a variety of cytokines that modulate the tumor microenvironment. This dual functionality encourages the destruction of cancer cells while simultaneously dismantling the immunosuppressive shield typically maintained by regulatory cells within the tumor milieu, thereby amplifying the overall immune assault on cancer.

The UCLA study undertook a rigorous comparison of four distinct CAR designs engineered into human NKT cells. Each CAR carries a targeting domain specific to mesothelin, a surface protein highly expressed in several solid tumors, including ovarian, pancreatic, lung, and breast cancers. The four CAR constructs varied primarily in their intracellular signaling and co-stimulatory domains: one featured CD28, another 4-1BB, the third incorporated both CD28 and 4-1BB, and the fourth employed NKG2D and 2B4 costimulatory motifs. These variations influence T cell activation, expansion, cytokine production, and longevity — all critical factors in the therapeutic efficacy of CAR-based immunotherapies.

The team first validated the cytotoxic capabilities of each CAR-NKT variant in vitro by exposing these engineered cells to tumor cells derived from multiple solid cancer types. They meticulously quantified tumor cell lysis, cytokine profiles, and the ability of the engineered NKT cells to persist over time. This extensive laboratory characterization revealed distinct performance profiles aligned with the signaling domains present in each CAR construct, underscoring how molecular engineering of CARs dictates both the intensity and durability of anti-tumor responses.

Following promising in vitro results, the researchers advanced to in vivo models, employing ovarian cancer mouse models to assess therapeutic outcomes. Here, they tracked tumor regression, survival outcomes, and biodistribution of the infused CAR-NKT cells within the animals. Notably, the 4-1BB-containing CAR design emerged as the leading candidate, demonstrating sustained anti-tumor activity coupled with prolonged cellular persistence. This construct outperformed its counterparts by maintaining a functional presence within tumors and secondary lymphoid tissues, translating into significantly improved survival metrics in treated mice.

The superior performance of the 4-1BB costimulatory domain aligns with previous findings in T cell-based therapies where 4-1BB signaling enhances cell survival and promotes a memory-like phenotype. This attribute is especially critical for solid tumor immunotherapy, where continuous immune surveillance and prolonged effector function are required to prevent tumor relapse and overcome immune evasion tactics. The study’s findings strongly suggest that optimizing intracellular signaling domains within CAR-NKT cells can tailor their function for maximal therapeutic benefit.

Importantly, the investigation also addressed safety concerns that often shadow novel cellular therapies. The engineered CAR-NKT cells did not induce off-target toxicity, displayed no signs of graft-versus-host disease (a dangerous immunological reaction common in allogeneic cell therapies), and showed no aberrant clonal expansion, alleviating fears of potential malignancies resulting from uncontrolled proliferation. These safety profiles bolster the clinical feasibility of using CAR-NKT cells as an off-the-shelf, allogeneic immunotherapy product.

This off-the-shelf capability distinguishes CAR-NKT therapy from conventional autologous CAR-T cell treatments, which require harvesting, engineering, and expanding each patient’s own T cells— a process that is time-consuming, expensive, and logistically complex. In contrast, CAR-NKT cells can be mass-produced from donated blood stem cells, cryopreserved, and distributed for immediate use. This paradigm shift could democratize access to advanced immunotherapies, dramatically reducing treatment delays and improving patient outcomes, especially for aggressive solid tumors needing urgent intervention.

The researchers have already published compelling preclinical evidence demonstrating the efficacy of CAR-NKT cells against multiple solid tumors beyond ovarian cancer, including pancreatic and triple-negative breast cancers, two notoriously challenging malignancies to treat. These findings collectively highlight the broad applicability and versatility of CAR-NKT cells across diverse tumor types, expanding the horizon of immunotherapy beyond hematologic cancers.

Dr. Lili Yang, the study’s senior author and a prominent figure in immunology and regenerative medicine at UCLA, emphasized the importance of this work. By systematically dissecting the functional differences among CAR designs in NKT cells, the study provides a critical roadmap for future clinical translation. It empowers scientists and clinicians with concrete data to select CAR configurations that balance immediate cytotoxicity and long-term immune memory, essential for sustained therapeutic success in solid tumor oncology.

As the field moves towards clinical trials, these insights lay the groundwork for a new generation of cellular immunotherapies that combine biological precision with manufacturing scalability. With continued validation, CAR-NKT cells stand poised to become a transformative weapon in the fight against cancer, potentially surmounting challenges that have long confined CAR-based therapies to blood cancers and revolutionizing the treatment landscape for solid tumors worldwide.

This research exemplifies the power of engineering biology at the molecular level to fine-tune immune interventions, combining the inherent tumor-penetrating capacity of NKT cells with tailored CAR signaling domains to create smart, potent cellular therapies. Such innovations reflect a broader trend in cancer immunotherapy towards harnessing the nuances of immune cell biology for optimized design and delivery — paving the way for more effective, safer, and widely accessible cancer treatments.

Subject of Research:
CAR-NKT Cell Therapy Design for Solid Tumor Immunotherapy

Article Title:
Engineering Optimal Chimeric Antigen Receptor Constructs for Allogeneic NKT Cell-Based Solid Tumor Immunotherapy

News Publication Date:
Not specified in the source content

Web References:
https://stemcell.ucla.edu/member-directory/lili-yang-phd
https://stemcell.ucla.edu/
https://www.uclahealth.org/cancer
https://newsroom.ucla.edu/releases/immunotherapy-car-nkt-pancreatic-cancer-ucla
https://newsroom.ucla.edu/releases/ucla-scientists-develop-one-product-fits-all-immunotherapy-breast-cancer
https://newsroom.ucla.edu/stories/immunotherapy-ovarian-cancer-ucla-scientists-develop
https://ashpublications.org/bloodict/article/2/1/100025/557344/Engineering-optimal-CAR-constructs-for-allogeneic

References:
Yanruide Li, Yichen Zhu, Tyler Halladay, Xinyuan Shen, Youcheng Yang, Zhe Li, Enbo Zhu, Yuning Chen, Jie Huang, and Lili Yang. “Engineering optimal CAR constructs for allogeneic invariant natural killer T cell therapy.” Blood Immunology & Cellular Therapy.

Image Credits:
UCLA Broad Stem Cell Research Center

Keywords:
Immunotherapy, Cancer Immunotherapy, Cancer, Cancer Cells, CAR-NKT Cells, Solid Tumors, Chimeric Antigen Receptors, 4-1BB Costimulatory Domain, Mesothelin Targeting, Cellular Therapy, Off-the-Shelf Immunotherapy, Tumor Microenvironment