Cell Metabolic Fitness Research Articles

Dietary Restriction Enhances CD8⁺ T Cell Ketolysis to Limit Exhaustion and Boost Anti-Tumor Immunity.

Reducing calorie intake without malnutrition limits tumor progression but the underlying mechanisms are poorly understood. Here we show that dietary restriction (DR) suppresses tumor growth by enhancing CD8 + T cell-mediated anti-tumor immunity. DR reshapes CD8 + T cell differentiation within the tumor microenvironment (TME), promoting the development of effector T cell subsets while limiting the accumulation of exhausted T (Tex) cells, and synergizes with anti-PD1 immunotherapy to restrict tumor growth. Mechanistically, DR enhances CD8 + T cell metabolic fitness through increased ketone body oxidation (ketolysis), which boosts mitochondrial membrane potential and fuels tricarboxylic acid (TCA) cycle-dependent pathways essential for T cell function. T cells deficient for ketolysis exhibit reduced mitochondrial function, increased exhaustion, and fail to control tumor growth under DR conditions. Our findings reveal a critical role for the immune system in mediating the anti-tumor effects of DR, highlighting nutritional modulation of CD8 + T cell fate in the TME as a critical determinant of anti-tumor immunity.

Sodium chloride in the tumor microenvironment enhances T cell metabolic fitness and cytotoxicity

The efficacy of antitumor immunity is associated with the metabolic state of cytotoxic T cells, which is sensitive to the tumor microenvironment. Whether ionic signals affect adaptive antitumor immune responses is unclear. In the present study, we show that there is an enrichment of sodium in solid tumors from patients with breast cancer. Sodium chloride (NaCl) enhances the activation state and effector functions of human CD8+ T cells, which is associated with enhanced metabolic fitness. These NaCl-induced effects translate into increased tumor cell killing in vitro and in vivo. Mechanistically, NaCl-induced changes in CD8+ T cells are linked to sodium-induced upregulation of Na+/K+-ATPase activity, followed by membrane hyperpolarization, which magnifies the electromotive force for T cell receptor (TCR)-induced calcium influx and downstream TCR signaling. We therefore propose that NaCl is a positive regulator of acute antitumor immunity that might be modulated for ex vivo conditioning of therapeutic T cells, such as CAR T cells.

GLUT1 overexpression enhances CAR T cell metabolic fitness and anti-tumor efficacy

The tumor microenvironment presents many obstacles to effective CAR T cell therapy, including glucose competition from tumor and myeloid cells. Using mouse models of acute lymphoblastic leukemia (ALL), renal cell carcinoma (RCC), and glioblastoma (GBM), we show that enforced expression of the glucose transporter GLUT1 enhances anti-tumor efficacy and promotes favorable CAR T cell phenotypes for two clinically relevant CAR designs, 19-28z and IL13Rα2-BBz. In the NALM6 ALL model, 19-28z-GLUT1 promotes Tscm formation and prolongs survival. RNA sequencing of these CAR T cells reveals that overexpression of GLUT1, but not GLUT3, enriches for genes involved in glycolysis, mitochondrial respiration, and memory precursor phenotypes. Extending these data, 19-28z-GLUT1 CAR T cells improve tumor control and response to rechallenge in an RCC patient derived xenograft model. Furthermore, IL13Rα2-BBz CAR T cells overexpressing GLUT1 prolong survival of mice bearing orthotopic GBMs and exhibit decreased exhaustion markers. This novel engineering approach can offer a competitive advantage to CAR T cells in harsh tumor environments where glucose is limiting.

Quality Assessment of Metabolic Fitness during T Cell and NK Cell Expansion

Abstract CAR-T cells have revolutionized cancer treatment, and other cell types like CAR-NK cells are also showing promising results. Engineered cells generally need to be expanded ex vivo before being transfused into patients. Growth conditions, including expansion platform, cell culture media, and cytokine composition, time of expansion, etc., can have a strong effect on the characteristics of the final products and need to be monitored to establish the appropriate development process. Recent developments highlight the significance of cell metabolism in influencing immune responses and the anti-tumor efficacy of cell therapies. In the present study, we utilized Seahorse XF technology and assays to characterize T cell and NK cell metabolic fitness during cell expansion. We cultured human T cells and NK cells under different expansion conditions including culture media, culture devices, and cytokine combinations, and sampled cells at different time points for quality assessment of metabolic fitness. Using the new Seahorse XF assay alongside immunophenotypic characterization using Novocyte Flow Cytometry, we obtained robust information on mitochondrial and glycolytic energy production, metabolic poise, and the bioenergetic capacity of the expanded cells, allowing us to identify conditions that resulted in increased metabolic fitness of the cell population that can contribute to defining cell expansion conditions during immunotherapy development.

FOXO1 enhances CAR T cell stemness, metabolic fitness and efficacy

Chimeric antigen receptor (CAR) T cell therapy has transformed the treatment of haematological malignancies such as acute lymphoblastic leukaemia, B cell lymphoma and multiple myeloma1–4, but the efficacy of CAR T cell therapy in solid tumours has been limited5. This is owing to a number of factors, including the immunosuppressive tumour microenvironment that gives rise to poorly persisting and metabolically dysfunctional T cells. Analysis of anti-CD19 CAR T cells used clinically has shown that positive treatment outcomes are associated with a more ‘stem-like’ phenotype and increased mitochondrial mass6–8. We therefore sought to identify transcription factors that could enhance CAR T cell fitness and efficacy against solid tumours. Here we show that overexpression of FOXO1 promotes a stem-like phenotype in CAR T cells derived from either healthy human donors or patients, which correlates with improved mitochondrial fitness, persistence and therapeutic efficacy in vivo. This work thus reveals an engineering approach to genetically enforce a favourable metabolic phenotype that has high translational potential to improve the efficacy of CAR T cells against solid tumours.

Abstract 5342: Evaluation of autologous and allogeneic T cell-based therapies in ex-vivo and in-vivo xenograft tumor models

Abstract The field of adoptive T cell-based immunotherapy, including tumor-infiltrating lymphocytes (TILs), T cell receptor (TCR) & Chimeric antigen receptor (CAR) - T cells, has undergone unprecedented growth, specifically later in delivering effective and durable clinical response. Notable success with CAR-T cells is limited to hematological malignancies while clinical gains with solid tumors is still a challenge. Solid tumors’ heterogenous target expression and loss, T cell status and metabolic fitness, T cell trafficking into the tumor, and the hostile immunosuppressive tumor microenvironment (TME) have hampered T cell efficacy in the patients. There is a lack of clinically relevant solid tumor models for the translation of T cell-based therapies into the clinic. We report the development of translational ex-vivo and in-vivo platforms for evaluating cell line-derived and patient-derived xenografts (CDX and PDX) models (BarneyOI™️ model), validated with hCD3 T-cells, autologous TILs and/or allogeneic 3rd generation CAR-T cells (scFv(HER2)-CD28-4-1BB-CD3zeta CAR-T). Anti-hPDL1 but not anti-hPD1 significantly enhanced hCD3 T-cell and autologous TIL-mediated killing of tumor cells in an ex-vivo co-culture assay using Incucyte-based live cell imaging. Also, a dose-dependent killing of HER-2 expressing CDX (A549 & Colo205) and PDX was observed with HER-2 targeting CAR-T cells in an ex-vivo co-culture assay. This was in concordance with the activation, effector function, and differentiation status of the CAR-T cells, immune phenotype by Cytek aurora spectral flow cytometry. Further, to imitate the patient population and the effect of solid TME, HER-2 targeting CAR-T cells were assessed for their in-vivo efficacy and immune response differences in the subcutaneous and orthotopically implanted HER-2 expressing PDX in immunodeficient NOG mice. Our findings highlight the importance of testing T cell-based immune therapies in the appropriate translational tumor models with better certainty of clinical outcome. Citation Format: Sherry Liu, Jasmine Borroel, Carmen Sunico, Emily Eastwood, Bridget Corcoran, Bianca Carapia, Jantzen Sperry, Jonathan Nakashima, Rajeev Shrimali. Evaluation of autologous and allogeneic T cell-based therapies in ex-vivo and in-vivo xenograft tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5342.

De novo NAD+ synthesis contributes to CD8+ T cell metabolic fitness and antitumor function

The dysfunction and clonal constriction of tumor-infiltrating CD8+ Tcells are accompanied by alterations in cellular metabolism; however, how the cell-intrinsic metabolic pathway specifies intratumoral CD8+ Tcell features remains elusive. Here, we show that cell-autonomous generation of nicotinamide adenine dinucleotide (NAD+) via the kynurenine pathway (KP) contributes to the maintenance of intratumoral CD8+ Tcell metabolic and functional fitness. De novo NAD+ synthesis is involved in CD8+ Tcell metabolism and antitumor function. KP-derived NAD+ promotes PTEN deacetylation, thereby facilitating PTEN degradation and preventing PTEN-dependent metabolic defects. Importantly, impaired cell-autonomous NAD+ synthesis limits CD8+ Tcell responses in human colorectal cancer samples. Our results reveal that KP-derived NAD+ regulates the CD8+ Tcell metabolic and functional state by restricting PTEN activity and suggest that modulation of de novo NAD+ synthesis could restore CD8+ Tcell metabolic fitness and antitumor function.

Mitochondria-ER contact mediated by MFN2-SERCA2 interaction supports CD8+ T cell metabolic fitness and function in tumors.

Metabolic fitness of T cells is essential for their vitality, which is largely dependent on the behavior of the mitochondria. The nature of mitochondrial behavior in tumor-infiltrating T cells remains poorly understood. In this study, we show that mitofusin-2 (MFN2) expression is positively correlated with the prognosis of multiple cancers. Genetic ablation of Mfn2 in CD8+ T cells dampens mitochondrial metabolism and function and promotes tumor progression. In tumor-infiltrating CD8+ T cells, MFN2 enhances mitochondria-endoplasmic reticulum (ER) contact by interacting with ER-embedded Ca2+-ATPase SERCA2, facilitating the mitochondrial Ca2+ influx required for efficient mitochondrial metabolism. MFN2 stimulates the ER Ca2+ retrieval activity of SERCA2, thereby preventing excessive mitochondrial Ca2+ accumulation and apoptosis. Elevating mitochondria-ER contact by increasing MFN2 in CD8+ T cells improves the efficacy of cancer immunotherapy. Thus, we reveal a tethering-and-buffering mechanism of organelle cross-talk that regulates the metabolic fitness of tumor-infiltrating CD8+ T cells and highlights the therapeutic potential of enhancing MFN2 expression to optimize T cell function.

Short-term dietary changes can result in mucosal and systemic immune depression

Omnivorous animals, including mice and humans, tend to prefer energy-dense nutrients rich in fat over plant-based diets, especially for short periods of time, but the health consequences of this short-term consumption of energy-dense nutrients are unclear. Here, we show that short-term reiterative switching to ‘feast diets’, mimicking our social eating behavior, breaches the potential buffering effect of the intestinal microbiota and reorganizes the immunological architecture of mucosa-associated lymphoid tissues. The first dietary switch was sufficient to induce transient mucosal immune depression and suppress systemic immunity, leading to higher susceptibility to Salmonella enterica serovar Typhimurium and Listeria monocytogenes infections. The ability to respond to antigenic challenges with a model antigen was also impaired. These observations could be explained by a reduction of CD4+ T cell metabolic fitness and cytokine production due to impaired mTOR activity in response to reduced microbial provision of fiber metabolites. Reintroducing dietary fiber rewired T cell metabolism and restored mucosal and systemic CD4+ T cell functions and immunity. Finally, dietary intervention with human volunteers confirmed the effect of short-term dietary switches on human CD4+ T cell functionality. Therefore, short-term nutritional changes cause a transient depression of mucosal and systemic immunity, creating a window of opportunity for pathogenic infection.

Asparagine restriction enhances CD8+ T cell metabolic fitness and antitumoral functionality through an NRF2-dependent stress response.

Robust and effective T cell immune surveillance and cancer immunotherapy require proper allocation of metabolic resources to sustain energetically costly processes, including growth and cytokine production. Here, we show that asparagine (Asn) restriction on CD8+ T cells exerted opposing effects during activation (early phase) and differentiation (late phase) following T cell activation. Asn restriction suppressed activation and cell cycle entry in the early phase while rapidly engaging the nuclear factor erythroid 2-related factor 2 (NRF2)-dependent stress response, conferring robust proliferation and effector function on CD8+ T cells during differentiation. Mechanistically, NRF2 activation in CD8+ T cells conferred by Asn restriction rewired the metabolic program by reducing the overall glucose and glutamine consumption but increasing intracellular nucleotides to promote proliferation. Accordingly, Asn restriction or NRF2 activation potentiated the T cell-mediated antitumoral response in preclinical animal models, suggesting that Asn restriction is a promising and clinically relevant strategy to enhance cancer immunotherapy. Our study revealed Asn as a critical metabolic node in directing the stress signaling to shape T cell metabolic fitness and effector functions.

The CD73 immune checkpoint promotes tumor cell metabolic fitness.

CD73 is an ectonucleotidase overexpressed on tumor cells that suppresses anti-tumor immunity. Accordingly, several CD73 inhibitors are currently being evaluated in the clinic, including in large randomized clinical trials. Yet, the tumor cell-intrinsic impact of CD73 remain largely uncharacterized. Using metabolomics, we discovered that CD73 significantly enhances tumor cell mitochondrial respiration and aspartate biosynthesis. Importantly, rescuing aspartate biosynthesis was sufficient to restore proliferation of CD73-deficient tumors in immune deficient mice. Seahorse analysis of a large panel of mouse and human tumor cells demonstrated that CD73 enhanced oxidative phosphorylation (OXPHOS) and glycolytic reserve. Targeting CD73 decreased tumor cell metabolic fitness, increased genomic instability and suppressed poly ADP ribose polymerase (PARP) activity. Our study thus uncovered an important immune-independent function for CD73 in promoting tumor cell metabolism, and provides the rationale for previously unforeseen combination therapies incorporating CD73 inhibition.

Immunometabolic modulation by targeting UCP2 and IL-17A boost anti-tumor immunity against pancreatic cancer

Abstract Metabolic reprograming of cytotoxic effectors by tumor microenvironment (TME) is one of the key mechanisms by which TME impairs the success of cancer immunotherapy. Therapeutic strategies that mitigate the immunosuppressive TME and selectively enhance bioenergetic fitness of cytotoxic effectors may enhance benefits of immunotherapy, particularly in TME-abundant pancreatic cancer. IL-17 is a key TME cytokine engaged in a feed-forward loop promoting the immunosuppressive milieu that facilitates cancer progression. Mitochondrial uncoupling protein 2 (UCP2) acts as an inhibitor of T cell metabolic fitness and directly promotes tumorigenesis. Therefore, we hypothesized that targeting IL-17 and UCP2 could act additionally to enhance antitumor immune response and directly inhibit pancreatic cancer growth. UCP2 deficiency regulated bioenergetic metabolism and mTOR signaling in cytotoxic T cells to enhance IFN-γ production and anti-tumor immune responses. UCP2 inhibition increased anti-tumor immunity in PBMCs and tumors of patients with PDAC. The dual inhibition of IL-17 and UCP2 boosted antitumor immunity and suppressed tumorigenesis in tumor-bearing mice. Combination of UCP2 and IL-17 blockade may offer additional complimentary and cooperative mechanisms of antitumor immunity against pancreatic cancer. 1. Ministry of Science and Technology (MOST 108-2320-B-039-024-MY3) 2. China Medical University Hospital (DMR-110-186) 3. Chinese Medicine Research Center, China Medical University from the Featured Areas Research 4. Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education (CMRC-CHM-2)

Linoleic acid potentiates CD8+ T cell metabolic fitness and antitumor immunity

The metabolic state represents a major hurdle for an effective adoptive Tcell therapy (ACT). Indeed, specific lipids can harm CD8+ Tcell (CTL) mitochondrial integrity, leading to defective antitumor responses. However, the extent to which lipids can affect the CTL functions and fate remains unexplored. Here, we show that linoleic acid (LA) is a major positive regulator of CTL activity by improving metabolic fitness, preventing exhaustion, and stimulating a memory-like phenotype with superior effector functions. We report that LA treatment enhances the formation of ER-mitochondria contacts (MERC), which in turn promotes calcium (Ca2+) signaling, mitochondrial energetics, and CTL effector functions. As a direct consequence, the antitumor potency of LA-instructed CD8 Tcells is superior invitro and invivo. We thus propose LA treatment as an ACT potentiator in tumor therapy.

Effects of the STAMP-inhibitor asciminib on T cell activation and metabolic fitness compared to tyrosine kinase inhibition by imatinib, dasatinib, and nilotinib

T cell function is central to immune reconstitution and control of residual chronic myeloid leukemia (CML) cells after treatment initiation and is associated with achieving deep molecular response as a prerequisite for treatment-free remission, the ultimate therapeutic goal in CML. ATP-pocket-binding tyrosine kinase inhibitors (TKIs) like imatinib, dasatinib, and nilotinib are widely used for treating CML, but they have shown to inhibit T cell function as an “off-target” effect. Therefore, we tested asciminib, the first-in-class BCR::ABL1 fusion protein inhibitor specifically targeting the ABL myristoyl pocket (STAMP) and compared its effects on T cell function with imatinib, dasatinib, and nilotinib. Whereas all four TKIs inhibited the expression of the co-stimulatory protein CD28, the amino acid transporter CD98, proliferation, and secretion of pro-inflammatory cytokines IFNγ, IL-6, and IL-17A upon T cell stimulation, asciminib had less impact on PD-1, activation markers, and IL-2 secretion. T cells treated with asciminib and the other TKIs maintained their ability to mobilize their respiratory capacity and glycolytic reserve, which is an important surrogate for metabolic fitness and flexibility. Overall, we found milder inhibitory effects of asciminib on T cell activation, which might be beneficial for the immunological control of residual CML cells.

Deletion of PD-1 destabilizes the lineage identity and metabolic fitness of tumor-infiltrating regulatory T cells.

Regulatory T (Treg) cells have an immunosuppressive function and highly express the immune checkpoint receptor PD-1 in the tumor microenvironment; however, the function of PD-1 in tumor-infiltrating (TI) Treg cells remains controversial. Here, we showed that conditional deletion of PD-1 in Treg cells delayed tumor progression. In Pdcd1fl/flFoxp3eGFP-Cre-ERT2(+/-) mice, in which both PD-1-expressing and PD-1-deficient Treg cells coexisted in the same tissue environment, conditional deletion of PD-1 in Treg cells resulted in impairment of the proliferative and suppressive capacity of TI Treg cells. PD-1 antibody therapy reduced the TI Treg cell numbers, but did not directly restore the cytokine production of TI CD8+ T cells in TC-1 lung cancer. Single-cell analysis indicated that PD-1 signaling promoted lipid metabolism, proliferation and suppressive pathways in TI Treg cells. These results suggest that PD-1 ablation or inhibition can enhance antitumor immunity by weakening Treg cell lineage stability and metabolic fitness in the tumor microenvironment.

Quadruple gene-engineered natural killer cells enable multi-antigen targeting for durable antitumor activity against multiple myeloma

Allogeneic natural killer (NK) cell adoptive transfer is a promising treatment for several cancers but is less effective for the treatment of multiple myeloma. In this study, we report on quadruple gene-engineered induced pluripotent stem cell (iPSC)-derived NK cells designed for mass production from a renewable source and for dual targeting against multiple myeloma through the introduction of an NK cell-optimized chimeric antigen receptor (CAR) specific for B cell maturation antigen (BCMA) and a high affinity, non-cleavable CD16 to augment antibody-dependent cellular cytotoxicity when combined with therapeutic anti-CD38 antibodies. Additionally, these cells express a membrane-bound interleukin-15 fusion molecule to enhance function and persistence along with knock out of CD38 to prevent antibody-mediated fratricide and enhance NK cell metabolic fitness. In various preclinical models, including xenogeneic adoptive transfer models, quadruple gene-engineered NK cells consistently demonstrate durable antitumor activity independent of exogenous cytokine support. Results presented here support clinical translation of this off-the-shelf strategy for effective treatment of multiple myeloma.

Abstract 2849: A novel solution to assess T cell metabolic phenotype for the optimization of antitumor T cell therapy products

Abstract In recent years, chimeric antigen receptor T (CAR-T) cells have shown significant promise in treating a range of cancers, with a number of approved products currently on the market. This has led to significant interest in optimizing cell therapy design and manufacturing. Traditionally, CAR-T cells are transfected expanded, and partially characterized before infusing into patients. However, the ability to predict in vivo efficacy is still challenging. Bioenergetic metabolism has been extensively linked to immune cell function and therefore represents a key attribute to be assessed during T cell therapy optimization and production. In addition, metabolic reprogramming can represent a mechanism to drive a desired immune phenotype. Agilent Seahorse XF T cell Metabolic Profiling kit is a robust new solution that combined with the Seahorse XF analyzer, allows for the simultaneous measurement of basal metabolic requirements, metabolic poise and mitochondrial bioenergetic capacity in T cells. These parameters have been shown to correlate with increased T cell persistence and improved metabolic fitness in nutrient restricted environments. This assay incorporates an improved uncoupler (BAM15) to allow more robust measurements of mitochondrial T cell bioenergetic capacity (measured as spare respiratory capacity or maximum respiration) with minimum optimization compared to uncouplers previously utilized. The XF T cell Metabolic Profiling kit has been used to evaluate the influence of expansion media composition on the metabolic phenotype of expanded human T cells. Indeed, when human T cells were activated and expanded up to 22 days in different commercial culture media formulations supplemented with different cytokine combinations, it resulted in T cell populations with differential bioenergetic profiles and mitochondrial spare capacities. These different metabolic phenotypes also correlated with different functional markers that have previously been associated with increased persistence in vivo. Similarly, the XF T cell Metabolic Profiling kit was used to assess metabolic poise and bioenergetic capacity of activated T cells under altered or restricted metabolic conditions like the ones present in the tumor microenvironment (low glucose, low glutamine), therefore allowing for better understanding of the effect of carbon source depletion during T cell stimulation. In addition, this assay coupled to the existing XF Hu T cell activation assay allowed for the assessment of T cell ‘fitness’ after re-stimulation in nutrient limited conditions. Taken together, the XF T cell Metabolic Profiling kit is a novel solution that provides a complete insight into the metabolic state of T cells in real-time, facilitating the evaluation of cell therapy expansion conditions and metabolic fitness of T cells under limited nutrient availability, which can be used to better design T cell therapies. Citation Format: Jessica Walls, Yoonseok Kam, Natalia Romero. A novel solution to assess T cell metabolic phenotype for the optimization of antitumor T cell therapy products [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2849.

Targeting Metabolic Reprogramming of T-Cells for Enhanced Anti-Tumor Response.

Cancer immunotherapy is an effective treatment option against cancer. One of the approaches of cancer immunotherapy is the modification of T cell-based anti-tumor immune responses. T-cells, a type of adaptive immune response cells responsible for cell-mediated immunity, have long been recognized as key regulators of immune-mediated anti-tumor immunity. T-cell activities have been reported to be suppressed or enhanced by changes in cell metabolism. Moreover, metabolic reprogramming during activation of T cells is required for the development of distinct differentiation profiles of these cells, which may allow the development of long-term cell-mediated anti-tumor immunity. However, T cells have been shown to undergo metabolic exhaustion in tumor microenvironment (TME) as it poses several obstacles to their function. Applications of several mechanistic solutions to improve the efficacy of T cell-based therapies including chimeric antigen receptor (CAR) T cell therapy are yet to be determined. Modifying the metabolic properties of these cells and employing them in cancer immunotherapy is a potential strategy for improving their anti-tumor activity and therapeutic efficacy. To give an insight, in this review paper, we endeavoured to cover metabolic reprogramming in cancer and T cells, signalling mechanisms involved in immuno-metabolic regulation, the effects of the TME on T cell metabolic fitness, and targeting metabolic reprogramming of T cells for an enhanced anti-tumor response.

Chimeric Cytokine Targeting NKG2D and IL-2 Receptor Augments CD8+ T Cell-Metabolic Fitness and Improves Immunotherapy

Abstract T cell mediated immunotherapy has gained credible traction for cancer treatment. To date experimental and clinical strategies have relied on antibody-mediated co-stimulatory blockade, or the administration of high doses of naturally occurring or engineered cytokines to increase T cell activation. Cytokine therapy is by limited undesirable off-target side effects as well as terminal differentiation and exhaustion of chronically stimulated T cells. Here we describe functionality of a unique chimeric cytokine by design, called OMCPmutIL-2, binds with high affinity to the cytotoxic lymphocyte-defining immunoreceptor NKG2D but signals through the common γ-chain cytokine receptor, thus eliminating IL-2Ra mediated off-target side effects. In addition to precise activation of cytotoxic T cells due to redirected binding we describe that OMCPmutIL-2 results in superior activation of both human and murine CD8+ T cells by improving their survival, decreasing exhaustion, and improving memory cell generation. This functional improvement is the result altered signal transduction based on the reorganization of surface membrane lipid rafts resulting in JAK-mediated phosphorylation of the T cell receptor (TCR) rather than canonical STAT/AKT signaling intermediates activated by other common γ-chain cytokines. This altered signaling pathway increases CD8+ T cell response to low affinity antigens, activates Nuclear Factor of Activated T Cells (NFAT) transcription factors, and enhances mitochondrial biogenesis with improved T cell survival, cytotoxicity, and memory cell generation. OMCPmutIL-2 thus outperforms other common γ-chain cytokines as both a reagent for T cell expansion and in vivo CD8+ T cell-based immunotherapy. Supported by grant I01 BX002299

Immune Cell Metabolic Fitness for Life.

Adoptive cell therapy holds great promise for treating a myriad of diseases, especially cancer. Within the last decade, immunotherapy has provided a significant leap in the successful treatment of leukemia. The research conducted throughout this period to understand the interrelationships between cancer cells and infiltrating immune cells winds up having one very common feature, bioenergetics. Cancer cells and immune cells both need ATP to perform their individual functions and cancer cells have adopted means to limit immune cell activity via changes in immune cell bioenergetics that redirect immune cell behavior to encourage tumor growth. Current leading strategies for cancer treatment super-charge an individual’s own immune cells against cancer. Successful Chimeric Antigen Receptor T Cells (CAR T) target pathways that ultimately influence bioenergetics. In the last decade, scientists identified that mitochondria play a crucial role in T cell physiology. When modifying T cells to create chimeras, a unique mitochondrial fitness emerges that establishes stemness and persistence. This review highlights many of the key findings leading to this generation’s CAR T treatments and the work currently being done to advance immunotherapy, to empower not just T cells but other immune cells as well against a variety of cancers.