Targeting Glutamine Research Articles

Synergistic Effects of Glutamine Deprivation and Metformin in Acute Myeloid Leukemia.

The metabolic reprogramming of acute myeloid leukemia (AML) cells is a compensatory adaptation to meet energy requirements for rapid proliferation. This study aimed to examine the synergistic effects of glutamine deprivation and metformin exposure on AML cells. SKM-1 cells (an AML cell line) were subjected to glutamine deprivation and/or treatment with metformin or bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl) ethyl sulfide (BPTES, a glutaminase inhibitor) or cytarabine. Cell viability was detected by Cell Counting Kit-8 (CCK-8) assay, and cell apoptosis and reactive oxygen species (ROS) by flow cytometry. Western blotting was conducted to examine the levels of apoptotic proteins, including cleaved caspase-3 and poly(ADP-ribose) polymerase (PARP). Moreover, the human long noncoding RNA (lncRNA) microarray was used to analyze gene expression after glutamine deprivation, and results were confirmed with quantitative RT-PCR (qRT-PCR). The expression of metallothionein 2A (MT2A) was suppressed using siRNA. Cell growth and apoptosis were further detected by CCK-8 assay and flow cytometry, respectively, in cells with MT2A knockdown. Glutamine deprivation or treatment with BPTES inhibited cell growth and induced apoptosis in SKM-1 cells. The lncRNA microarray result showed that the expression of MT family genes was significantly upregulated after glutamine deprivation. MT2A knockdown increased apoptosis, while proliferation was not affected in SKM-1 cells. In addition, metformin inhibited cell growth and induced apoptosis in SKM-1 cells. Both glutamine deprivation and metformin enhanced the sensitivity of SKM-1 cells to cytarabine. Furthermore, the combination of glutamine deprivation with metformin exhibited synergistic antileukemia effects on SKM-1 cells. Targeting glutamine metabolism in combination with metformin is a promising new therapeutic strategy for AML.

Targeting YAP Activity and Glutamine Metabolism Cooperatively Suppresses Tumor Progression by Preventing Extracellular Matrix Accumulation.

Cancer cells use multiple mechanisms to evade the effects of glutamine metabolism inhibitors. The pathways that govern responses to alterations in glutamine availability within the tumor may represent therapeutic targets for combinatorial strategies with these inhibitors. Here, we showed that targeting glutamine utilization stimulated Yes-associated protein (YAP) signaling in cancer cells by reducing cyclic adenosine monophosphate/protein kinase A (PKA)-dependent phosphorylation of large tumor suppressor (LATS). Elevated YAP activation induced extracellular matrix (ECM) deposition by increasing the secretion of connective tissue growth factor that promoted the production of fibronectin and collagen by surrounding fibroblasts. Consequently, inhibiting YAP synergized with inhibition of glutamine utilization to effectively suppress tumor growth in vivo, along with a concurrent decrease in ECM deposition. Blocking ECM remodeling also augmented the tumor suppressive effects of the glutamine utilization inhibitor. Collectively, these data reveal mechanisms by which targeting glutamine utilization increases ECM accumulation and identify potential strategies to reduce ECM levels and increase the efficacy of glutamine metabolism inhibitors. Significance: Blocking glutamine utilization activates YAP to promote ECM deposition by fibroblasts, highlighting the potential of YAP inhibitors and antifibrotic strategies as promising approaches for effective combination metabolic therapies in cancer.

Targeting glutamine metabolism improves sarcoma response to radiation therapy in vivo

Diverse tumor metabolic phenotypes are influenced by the environment and genetic lesions. Whether these phenotypes extend to rhabdomyosarcoma (RMS) and how they might be leveraged to design new therapeutic approaches remains an open question. Thus, we utilized a Pax7Cre-ER-T2/+; NrasLSL-G12D/+; p53fl/fl (P7NP) murine model of sarcoma with mutations that most frequently occur in human embryonal RMS. To study metabolism, we infuse 13C-labeled glucose or glutamine into mice with sarcomas and show that sarcomas consume more glucose and glutamine than healthy muscle tissue. However, we reveal a marked shift from glucose consumption to glutamine metabolism after radiation therapy (RT). In addition, we show that inhibiting glutamine, either through genetic deletion of glutaminase (Gls1) or through pharmacological inhibition of glutaminase, leads to significant radiosensitization in vivo. This causes a significant increase in overall survival for mice with Gls1-deficient compared to Gls1-proficient sarcomas. Finally, Gls1-deficient sarcomas post-RT elevate levels of proteins involved in natural killer cell and interferon alpha/gamma responses, suggesting a possible role of innate immunity in the radiosensitization of Gls1-deficient sarcomas. Thus, our results indicate that glutamine contributes to radiation response in a mouse model of RMS.

Abstract 6741: Targeting glutamine metabolism potentiates antigen presentation in colorectal cancer

Abstract Colorectal cancer (CRC) ranks among the most prevalent cancers worldwide, causing substantial mortality. The urgent need for effective treatments has driven research into immune checkpoint blockade (ICB) therapies, which have demonstrated significant clinical benefits across various cancer types. Despite the success of ICB therapies, a significant proportion of CRC patients exhibit resistance to treatment, prompting the identification of mechanisms that hinder therapy resistance or enhance treatment response. CRC cells display remarkable adaptability, orchestrating metabolic changes that confer growth advantages, pro-tumor microenvironment, and therapeutic resistance. One such metabolic change occurs in glutamine metabolism. In this study, we found that colorectal tumors with high glutaminase (GLS) expression exhibit reduced T-cell infiltration and cytotoxicity, leading to poor clinical outcomes. To validate these findings, we applied the ovalbumin (OVA)/OT-I T cell-based cytotoxicity assay and the CRC patient-derived organoids (PDOs)/autologous T cell killing assay. Our results indicated that inhibition of GLS significantly enhanced T-cell cytotoxicity in vitro and ex vivo. Mechanistically, we elucidated that inhibition of GLS activated reactive oxygen species-related signaling pathways in tumor cells, thereby potentially increasing tumor immunogenicity by promoting antigen presentation. The combinational therapy of GLS inhibitor and ICB exhibited a superior tumor growth inhibitory effect in comparison with either of the monotherapies. These findings shed new light on clinical therapeutic strategies for CRC patients, offering a promising approach to enhance the efficacy of ICB therapy. Citation Format: Tao Yu, Kevin Van der Jeught, Haiqi Zhu, Zhuolong Zhou, Samantha Sharma, Sheng Liu, Ka Man So, Haniyeh Eyvani, Xiyu Wang, George E. Sandusky, Yunlong Liu, Mateusz Opyrchal, Sha Cao, Jun Wan, Chi Zhang, Xinna Zhang. Targeting glutamine metabolism potentiates antigen presentation in colorectal cancer [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 6741.

Abstract 1770 Targeting glutamine availability with glutaminase 1-based glioblastoma therapy

Abstract 1770 Targeting glutamine availability with glutaminase 1-based glioblastoma therapy

Targeting glutamine metabolism exhibits anti-tumor effects in thyroid cancer

BackgroundEffective treatment for patients with advanced thyroid cancer is lacking. Metabolism reprogramming is required for cancer to undergo oncogenic transformation and rapid tumorigenic growth. Glutamine is frequently used by cancer cells for active bioenergetic and biosynthetic needs. This study aims to investigate whether targeting glutamine metabolism is a promising therapeutic strategy for thyroid cancer.MethodsThe expression of glutaminase (GLS) and glutamate dehydrogenase (GDH) in thyroid cancer tissues was evaluated by immunohistochemistry, and glutamine metabolism-related genes were assessed using real time-qPCR and western blotting. The effects of glutamine metabolism inhibitor 6-diazo-5-oxo-l-norleucine (DON) on thyroid cancer cells were determined by CCK-8, clone formation assay, Edu incorporation assay, flow cytometry, and Transwell assay. The mechanistic study was performed by real time-qPCR, western blotting, Seahorse assay, and gas chromatography–mass spectrometer assay. The effect of DON prodrug (JHU-083) on thyroid cancer in vivo was assessed using xenograft tumor models in BALB/c nude mice.ResultsGLS and GDH were over-expressed in thyroid cancer tissues, and GLS expression was positively associated with lymph-node metastasis and TNM stage. The growth of thyroid cancer cells was significantly inhibited when cultured in glutamine-free medium. Targeting glutamine metabolism with DON inhibited the proliferation of thyroid cancer cells. DON treatment did not promote apoptosis, but increased the proportion of cells in the S phase, accompanied by the decreased expression of cyclin-dependent kinase 2 and cyclin A. DON treatment also significantly inhibited the migration and invasion of thyroid cancer cells by reducing the expression of N-cadherin, Vimentin, matrix metalloproteinase-2, and matrix metalloproteinase-9. Non-essential amino acids, including proline, alanine, aspartate, asparagine, and glycine, were reduced in thyroid cancer cells treated with DON, which could explain the decrease of proteins involved in migration, invasion, and cell cycle. The efficacy and safety of DON prodrug (JHU-083) for thyroid cancer treatment were verified in a mouse model. In addition to suppressing the proliferation and metastasis potential of thyroid cancer in vivo, enhanced innate immune response was also observed in JHU-083-treated xenograft tumors as a result of decreased expression of cluster of differentiation 47 and programmed cell death ligand 1.ConclusionsThyroid cancer exhibited enhanced glutamine metabolism, as evidenced by the glutamine dependence of thyroid cancer cells and high expression of multiple glutamine metabolism-related genes. Targeting glutamine metabolism with DON prodrug could be a promising therapeutic option for advanced thyroid cancer.

Targeting glutamine dependence with DRP-104 inhibits proliferation and tumor growth of castration-resistant prostate cancer.

Prostate cancer (PCa) continues to be one of the leading causes of cancer deaths in men. While androgen deprivation therapy is initially effective, castration-resistant PCa (CRPC) often recurs and has limited treatment options. Our previous study identified glutamine metabolism to be critical for CRPC growth. The glutamine antagonist 6-diazo-5-oxo-l-norleucine (DON) blocks both carbon and nitrogen pathways but has dose-limiting toxicity. The prodrug DRP-104 is expected to be preferentially converted to DON in tumor cells to inhibit glutamine utilization with minimal toxicity. However, CRPC cells' susceptibility to DRP-104 remains unclear. Human PCa cell lines (LNCaP, LAPC4, C4-2/MDVR, PC-3, 22RV1, NCI-H660) were treated with DRP-104, and effects on proliferation and cell death were assessed. Unbiased metabolic profiling and isotope tracing evaluated the effects of DRP-104 on glutamine pathways. Efficacy of DRP-104 in vivo was evaluated in a mouse xenograft model of neuroendocrine PCa, NCI-H660. DRP-104 inhibited proliferation and induced apoptosis in CRPC cell lines. Metabolite profiling showed decreases in the tricarboxylic acidcycle and nucleotide synthesis metabolites. Glutamine isotope tracing confirmed the blockade of both carbon pathway and nitrogen pathways. DRP-104 treated CRPC cells were rescued by the addition of nucleosides. DRP-104 inhibited neuroendocrine PCa xenograft growth without detectable toxicity. The prodrug DRP-104 blocks glutamine carbon and nitrogen utilization, thereby inhibiting CRPC growth and inducing apoptosis. Targeting glutamine metabolism pathways with DRP-104 represents a promising therapeutic strategy for CRPC.

Targeting Glutamine Dependence through GLS1 Inhibition Suppress Multiple Myeloma and Phenomenon of Sars-Cov-2 Infectious Disease

Introduction: Multiple myeloma (MM) is characterized by the clonal expansion of plasma cells in the bone marrow. The treatment of MM patients has been dramatically changed by new agents, however, many patients will relapse even if new agents provide therapeutic advantages. Therefore, a new strategy is still needed to increase MM patient survival. Metabolic reprogramming is recognized as one of the hallmarks of cancer cells. Glutamine is the most abundant circulating amino acid in blood, glutamine metabolism through glutaminolysis may be associated with myeloma cell survival. The outbreak of coronavirus disease 2019 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, has rapidly spread to more than 196 countries worldwide. Myeloma patients present an increased risk for severe COVID-19 infection and poor outcomes. Materials and Methods: In this study, we investigated whether glutaminase (GLS) inhibitor, telaglenastat could suppress myeloma cells and enhance the sensitivity of myeloma cells to histone deacetylase (HDAC) inhibition. We also investigated whether telaglenastat suppress the SARS-CoV-2 phenomenon by using mouse macrophage cell line, RAW264. Results: We first investigated the GLS gene expression against MM patients from the online Gene Expression Omnibus (GEO) data. GLS1 expression was increased in monoclonal gammopathy of undetermined significance (MGUS) and myeloma patients compared to normal controls. We next investigated the glutaminolysis in myeloma cells. Deprivation of glutamine from the culture medium revealed that cellular growth inhibition and increased caspase 3/7 activity. We next evaluated the effect of GLS inhibitor, telaglenastat. MM cells were inhibited by telaglenastat in a dose dependent manner. Cellular cytotoxicity was also increased. Glutamine is converted by GLS into glutamate and alpha-ketoglutarate (α-KG), and related nicotinamide adenine dinucleotide phosphate (NADP) production. Intracellular α-KG and NADPH were reduced by telaglenastat. As metabolites are the substrates used to generate chromatin modification including acetylation of histone, we investigated HDAC inhibitor, panobinostat in myeloma cells. Myeloma cells were inhibited by panobinostat and histone acetylation, caspase 3/7 activity and cytotoxicity were increased. Combined treatment with panobinostat and telaglenastat caused more cytotoxicity. Sub-G1 phase was increased by cell cycle analysis. Caspase 3/7 activity and cellular cytotoxicity were also increased. Proteasomal activity was reduced. Immunoblot analysis revealed cleaved caspase 3 and γ- H2AX were increased by panobinostat and telaglenastat treatment. GLS shRNA transfectant cells were inhibited cellular proliferation and GLS shRNA transfectant cells were increased the sensitivity of panobinostat. We next investigated the effects of COVID-19 S1 protein and teragrenastat by using RAW264 cells. Gene expression of inflammatory cytokines, such as tumor necrosis factor α (TNFα) was induced by COVID-19 S1 protein treatment and inhibited by telaglenastat. Intracellular reactive oxygen species (ROS) and NFkB-p65 (Ser536) phosphate activity was increased by COVID-19 S1 protein and inhibited by telaglenastat. Conclusion: The GLS is involved myeloma progress and GLS inhibitor suppresses myeloma cells and enhance cytotoxic effects of HDAC inhibitor. We also provide the GLS inhibitor is effective to SARS-CoV-2 phenomenon and promising clinical relevance as a candidate drug for treatment of myeloma patients in COVID-19 pandemic.

TC2N Promotes Cell Proliferation and Metastasis in Hepatocellular Carcinoma by Targeting the Wnt/β-Catenin Signaling Pathway

Hepatocellular carcinoma (HCC), one of the most prevalent types of cancer worldwide, has an exceedingly poor prognosis. Tandem C2 domain nuclear protein (TC2N) has been implicated in tumorigenesis and serves as an oncogene or tumor suppressor in different types of cancer. Here, we explore the possible regulatory activities and molecular mechanisms of TC2N in HCC progression. However, TC2N expression was significantly upregulated in HCC tissues and hepatoma cell lines, and this upregulation was positively correlated with tumor progression in HCC patients. The ectopic overexpression of TC2N accelerated the proliferation, migration, and invasion of HCC cells, whereas its knockdown showed the opposite effects. Bioinformatics analysis showed that TC2N participates in the regulation of the Wnt/β-catenin signaling pathway. Mechanistically, TC2N activated the Wnt/β-catenin signaling pathway by regulating the expression levels of β-catenin and its downstream targets CyclinD1, MMP7, c-Myc, c-Jun, AXIN2, and glutamine synthase. Furthermore, the deletion of β-catenin effectively neutralized the regulation of TC2N in HCC proliferation and metastasis. Overall, this study showed that TC2N promotes HCC proliferation and metastasis by activating the Wnt/β-catenin signaling pathway, indicating that TC2N might be a potential molecular target for the treatment of HCC.

Targeting Glutamine Metabolism through Glutaminase Inhibition Suppresses Cell Proliferation and Progression in Nasopharyngeal Carcinoma.

Glutaminase (GLS), the key enzyme involved in glutamine metabolism, has been identified as a critical player in tumor growth and progression. The GLS inhibitor CB-839 has entered several clinical trials against a variety of tumors. Our study aimed to investigate the role and underlying mechanism of GLS and its inhibitor CB-839 in nasopharyngeal carcinoma (NPC). The expression, downstream genes, and signaling pathways of GLS in NPC were determined by real-time polymerase chain reaction (RT-PCR), PCR array, western blotting (WB), and immunohistochemical staining (IHC), and the phenotype of GLS was confirmed by in vivo experiments of subcutaneous tumor formation in mice and in vitro experiments of functional biology, including Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry, transwell migration, and Boyden invasion assay. Finally, it was also verified whether the treatment of NPC cells by GLS inhibitor CB-839 can change various biological functions and protein expression to achieve the purpose of blocking tumor progression. GLS was remarkably overexpressed in NPC cells and tissues, predicting a poor overall survival of NPC patients. GLS promoted cell cycle, proliferation, colony formation, migratory, and invasive capacities by regulating Cyclin D2 (CCND2) via PI3K/AKT/mTOR pathway in NPC in vitro and in vivo. Notably, CB-839 showed an effective anti-NPC tumor effect by blocking the biological functions of the tumor. The first innovative proof is that GLS promotes cell proliferation by regulating CCND2 via PI3K/AKT/mTOR pathway in NPC, and GLS inhibitor CB-839 may serve as a new potential therapeutic target for NPC treatment.

Targeting glutamine metabolic reprogramming of SLC7A5 enhances the efficacy of anti-PD-1 in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a heterogeneous disease that is characterized by metabolic disruption. Metabolic reprogramming and tumor cell immune escape play indispensable roles in the tumorigenesis that leads to TNBC. In this study, we constructed and validated two prognostic glutamine metabolic gene models, Clusters A and B, to better discriminate between groups of TNBC patients based on risk. Compared with the risk Cluster A patients, the Cluster B patients tended to exhibit better survival outcomes and higher immune cell infiltration. In addition, we established a scoring system, the glutamine metabolism score (GMS), to assess the pattern of glutamine metabolic modification. We found that solute carrier family 7 member 5 (SLC7A5), an amino acid transporter, was the most important gene and plays a vital role in glutamine metabolism reprogramming in TNBC cells. Knocking down SLC7A5 significantly inhibited human and mouse TNBC cell proliferation, migration, and invasion. In addition, downregulation of SLC7A5 increased CD8+ T-cell infiltration. The combination of a SLC7A5 blockade mediated via JPH203 treatment and an anti-programmed cell death 1 (PD-1) antibody synergistically increased the immune cell infiltration rate and inhibited tumor progression. Hence, our results highlight the molecular mechanisms underlying SLC7A5 effects and lead to a better understanding of the potential benefit of targeting glutamine metabolism in combination with immunotherapy as a new therapy for TNBC.

Glutamine availability unleashes dendritic cells’ anti-tumor power

Metabolic competition within the tumor microenvironment (TME) shapes the efficacy of anticancer immunity. In the August 3rd issue of Nature, Guo etal.1 show that glutamine is an intercellular metabolic checkpoint between cancer and immune cells. Targeting glutamine metabolism in the TME is a promising strategy to improve anti-cancer therapy.

Exosomal MiR-381 from M2-polarized macrophages attenuates urethral fibroblasts activation through YAP/GLS1-regulated glutaminolysis.

Post-traumatic urethral stricture is a clinical challenge for both patients and clinicians. Targeting glutamine metabolism to suppress excessive activation of urethral fibroblasts (UFBs) is assumed to be a potent and attractive strategy for preventing urethral scarring and stricture. In cellular experiments, we explored whether glutaminolysis meets the bioenergetic and biosynthetic demands of quiescent UFBs converted into myofibroblasts. At the same time, we examined the specific effects of M2-polarized macrophages on glutaminolysis and activation of UFBs, as well as the mechanism of intercellular signaling. In addition, findings were further verified in vivo in New Zealand rabbits. It revealed that glutamine deprivation or knockdown of glutaminase 1 (GLS1) significantly inhibited UFB activation, proliferation, biosynthesis, and energy metabolism; however, these effects were rescued by cell-permeable dimethyl α-ketoglutarate. Moreover, we found that exosomal miR-381 derived from M2-polarized macrophages could be ingested by UFBs and inhibited GLS1-dependent glutaminolysis, thereby preventing excessive activation of UFBs. Mechanistically, miR-381 directly targets the 3'UTR of Yes-associated protein (YAP) mRNA to reduce its stability at the transcriptional level, ultimately downregulating expression of YAP, and GLS1. In vivo experiments revealed that treatment with either verteporfin or exosomes derived from M2-polarized macrophages significantly reduced urethral stricture in New Zealand rabbits after urethral trauma. Collectively, this study demonstrates that exosomal miR-381 from M2-polarized macrophages reduces myofibroblast formation of UFBs and urethral scarring and stricture by inhibiting YAP/GLS1-dependent glutaminolysis.

Selected Articles from This Issue

Highlights| June 01 2023 Selected Articles from This Issue Author & Article Information Online ISSN: 1538-8514 Print ISSN: 1535-7163 ©2023 American Association for Cancer Research2023American Association for Cancer Research Mol Cancer Ther (2023) 22 (6): 691. https://doi.org/10.1158/1535-7163.MCT-22-6-HI Related Content A commentary has been published: Predicting the Abscopal Effect: Associated Tumor Histologic Subtypes and Biomarkers A commentary has been published: Activating an Adaptive Immune Response with a Telomerase-Mediated Telomere Targeting Therapeutic in Hepatocellular Carcinoma A commentary has been published: Targeting RET Solvent-Front Mutants with Alkynyl Nicotinamide-Based Inhibitors View more A commentary has been published: Targeting Glutamine Metabolism with a Novel Na+/K+-ATPase Inhibitor RX108 in Hepatocellular Carcinoma View less Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn Email Tools Icon Tools Get Permissions Cite Icon Cite Search Site Article Versions Icon Versions Version of Record June 1 2023 Citation Selected Articles from This Issue. Mol Cancer Ther 1 June 2023; 22 (6): 691. https://doi.org/10.1158/1535-7163.MCT-22-6-HI Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest Search Advanced Search Hepatocellular carcinoma (HCC) remains a global medical burden with a rising incidence and has a dismal prognosis. Cancer cells, including HCC cells, exhibit an oncogenetically driven addiction to the neutral amino acid glutamine. Here, Wei et al. report that drug candidate RX108, a novel small-molecule inhibitor of Na+/K+-ATPase, exerts potent antitumor activities and significantly decreases cell energy metabolism in HCC cells and xenograft model. Intriguingly, the antiproliferative effect of RX108 is dependent on glutamine transport and mediated by ASCT2 (SLC1A5), a sodium-dependent transporter for glutamine. These findings reveal a novel approach to target glutamine metabolism through inhibiting Na+/K+-ATPase. Radiation therapy has historically been used for localized cancer treatment with curative intent. However, recent advances in immunotherapy and its integration into standard cancer care have brought attention to the intriguing 'abscopal effect.' Nelson and colleagues shed light on this once poorly understood phenomenon,... You do not currently have access to this content.

P-187 Targeting glutamine metabolism and EGFR in RAS wildtype colorectal cancer

P-187 Targeting glutamine metabolism and EGFR in RAS wildtype colorectal cancer

Advances in Research on the Relationship between Glutamine Metabolism and Breast Cancer

Breast cancer is the highest incidence of cancer in women. In recent years, the incidence of breast cancer has been climbing, and the age is becoming younger and younger. Recent studies have shown that glutamine metabolism can promote the occurrence and progression of breast cancer, and is related to malignant proliferation, metastasis and drug resistance of breast cancer. Targeting glutamine metabolism is an important strategy for the treatment of breast cancer. This article reviews the mechanism of glutamine metabolism in breast cancer cells and its research progress and therapeutic significance in different molecular subtypes of breast cancer.

Targeting glutamine metabolism mitigates Foxp3-deficiency mediated disease

Abstract Regulatory T (Treg) cells play a key role in enforcing peripheral immunological tolerance to self-antigens. Foxp3 has been widely described as a master regulator for Treg differentiation and maintenance of their suppressive functions. Upon Foxp3 loss of function mutations, Foxp3-deficient Tregs (ΔTreg) develop in the thymus, however, these cells present impaired suppressive capacity and an effector T cell (Teff)-like phenotype. Among the Teff-like characteristics is the shift in their metabolism towards glycolysis and enhanced mitochondrial respiration. Metabolomic analysis revealed an increase in glutamine consumption. Here, we used 6-diazo-5-oxo-norleucine (DON), a broad inhibitor of glutamine-utilizing enzymes to treat Foxp3 deficient mice (Foxp3 ΔeGFPiCre), and observed a significant decrease in Teff cell activation, and IFNγ production from both ΔTreg and Teff cells together with a significant increase in survival. This effect was enhanced when we combined DON treatment with a ΔTreg specific Rictor depletion (Foxp3 ΔeGFPiCreRictor Δ/Δ). Given that glutamine is a key amino acid for T cell activation, we evaluated if this was a pan-T cell effect by inducing Treg depletion in Foxp3 DTRmice with concomitant DON treatment. Surprisingly, in the absence of Tregs, DON was not able to prevent autoimmune disease. These results suggest that DON mitigates Foxp3-deficiency mediated disease in a ΔTreg dependent manner, by improving their suppressive capacities. We are currently performing metabolomic studies to better understand the role of glutamine usage in ΔTreg, more specifically if glutamine is directed to glutaminolysis, nucleotide or glutathione synthesis and how this contributes to Treg cell loss of function. NIH grant 1R01AI153174

Targeting glutamine metabolism with photodynamic immunotherapy for metastatic tumor eradication

Immune checkpoint blockade (ICB) has shown significant clinical success, yet its responses can vary due to immunosuppressive tumor microenvironments. To enhance antitumor immunity, combining ICB therapy with tumor metabolism reprogramming may be a promising strategy. In this study, we developed a photodynamic immunostimulant called BVC aiming to boost immune recognition and prevent immune escape for metastatic tumor eradication by reprogramming glutamine metabolism. BVC, a carrier free self-assembled nanoparticle, comprises a photosensitizer (chlorin e6), an ASCT2 inhibitor (V9302) and a PD1/PDL1 blocker (BMS-1), offering favorable stability and enhanced drug delivery efficiency. The potent photodynamic therapy (PDT) capability of BVC is attributed to its regulation of glutamine metabolism, which influences the redox microenvironment within tumor tissues. By targeting ASCT2-mediated glutamine metabolism, BVC inhibits glutamine transport and GSH synthesis, leading to the upregulation of Fas and PDL1. Additionally, BVC-mediated PDT induces immunogenic cell death, triggering a cascade of immune responses. Consequently, BVC not only enhances immune recognition between CD8+ T cells and Fas-overexpressing tumor cells but also reduces tumor cell immune escape through PD1/PDL1 blockade, significantly benefiting metastatic tumor eradication. This study paves a novel approach for multi-synergistic tumor treatment.

Abstract 3972: Novel renal cell carcinoma therapy targeting glutaminolysis

Abstract Objective: Metabolic reprogramming of cancer cells contributes to tumor development and provides a target for cancer therapy ASCT2 is a glutamine transporter on the plasma membrane. Glutamine is converted into the cell to glutamate by glutaminase (GLS) and utilized by the TCA cycle. This glutaminolysis has been implicated in tumor progression in various malignancies, including renal cell carcinoma. In the present study, we investigated whether the unique strategy that effectively targets glutamine addiction would be effective as a treatment for RCC. Methods: Tumor tissue (T) and normal renal tissue (N) from surgical specimens of 66 patients with RCC were collected, and metabolomic analysis using liquid chromatography-mass spectrometry (LC/MS) to calculate the T/N ratio of Gln and Glu, respectively, were performed. In addition, immunohistological (IHC) staining of paraffin-embedded sections of 106 metastatic RCC cases was used to compare GLS and ASCT2 expression in tumor and normal tissue. In vitro, cell viability of the human RCC cell lines 786-O and 769-P was assessed by WST-8 assays. The protein expression was detected by Western blotting. Intracellular concentrations of glutamine and glutamate were analyzed using LC/MS. V9302 was used as the specific ASCT2 inhibitor, and CB839 as the specific GLS inhibitor. As the xenograft model in vivo, athymic nude mice were injected subcutaneously with 786-O cells and given various doses of V9302 and CB839 intraperitoneally. Results: LC/MS assays using surgical specimens showed a notable increase in glutamine concentration in tumor tissue. IHC assays confirmed high expression of ASCT2 in tumor tissue, and patients with high expression of ASCT2 had a poorer prognosis than those with low expression. Treatment of V9302 with 786-O and 769-P resulted in a limited decrease in cell viability. LC/MS analysis confirmed that V9302 treatment reduced glutathione metabolites. V9302 administration was shown to increase intracellular glutamine levels, presumably by compensatory mechanisms, whereas the combination of V9302 and CB839 significantly decreased glutamine levels in 786-O cells. Western blot analysis showed that the expression levels of ASCT2 and GLS1 decreased after the combination therapy. The xenograft study confirmed that the combination of V9302 and CB839 significantly inhibited 786-O tumor growth compared with controls within three weeks after treatment (p <0.001). Conclusion: It has been shown that ASCT2 expression is a marker of poor prognosis in RCC and that suppression of ASCT2 has an antitumor effect by affecting glutathione metabolism. On the other hand, the administration of V9302 raised the issue that a compensatory mechanism increases intracellular glutamine levels. Our results suggest that a novel combination strategy using CB839 in addition to V9302 could overcome the tolerance for the monotherapy and effectively target glutamine addiction in RCC. Citation Format: Yoshinari Muto, Akihito Takeuchi, Kenji Zennami, Eiji Sugihara, Ryoichi Shiroki, Hideyuki Saya, Makoto Sumitomo. Novel renal cell carcinoma therapy targeting glutaminolysis. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3972.

MP04-11 TARGETING GLUTAMINE ADDICTION WITH POTENT DRUG COMBINATION THERAPY FOR RENAL CELL CARCINOMA

You have accessJournal of UrologyCME1 Apr 2023MP04-11 TARGETING GLUTAMINE ADDICTION WITH POTENT DRUG COMBINATION THERAPY FOR RENAL CELL CARCINOMA Yoshinari Muto, Akihito Takeuchi, Kenji Zennami, Eiji Sugihara, Ryoichi Shiroki, Hideyuki Saya, and Makoto Sumitomo Yoshinari MutoYoshinari Muto More articles by this author , Akihito TakeuchiAkihito Takeuchi More articles by this author , Kenji ZennamiKenji Zennami More articles by this author , Eiji SugiharaEiji Sugihara More articles by this author , Ryoichi ShirokiRyoichi Shiroki More articles by this author , Hideyuki SayaHideyuki Saya More articles by this author , and Makoto SumitomoMakoto Sumitomo More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003215.11AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The glutamine-dependent nature of cancer cells could be used as a new strategy for treating cancers that do not have drug-driver genes, such as renal cell carcinoma (RCC). We recently reported that Alanine-serine-cysteine transporter 2 (ASCT2) is associated with metastatic progression and survival in RCC. However, the administration of V9302, a specific inhibitor of ASCT2, raised the issue that intracellular glutamine levels are increased by a compensatory mechanism (presented at 2021 AUA annual meeting). In the present study, we investigated whether the combination strategy that effectively targets glutamine addiction would be effective as a treatment for RCC. METHODS: The human RCC cell lines, 786-O and 769-P were used. The protein expression was detected by Western blotting. Cell viability was assessed using WST-8 assay. Intracellular concentrations of glutamine and glutamate were analyzed using liquid chromatography-mass spectrometry (LC/MS). V9302 was used as the specific ASCT2 inhibitor and CB839 as the specific GLS inhibitor. As the xenograft model in vivo, athymic nude mice were injected subcutaneously with 786-O cells and given various doses of V9302 and CB839 intraperitoneally. RESULTS: LC/MS assays showed that intracellular glutamine levels in the RCC cell line increased after 48 hours of treatment with V9302 alone, but that glutamine levels were significantly reduced by the combination of V9302 and CB839. Western blot analysis showed that the expression levels of ASCT2 and GLS1 were both decreased after the combination therapy. The tumor xenograft study confirmed that the combination of V9302 (30 mg/kg, intraperitoneal injection) and CB839 (20 mg/kg, intraperitoneal injection) significantly inhibited 786-O tumor growth compared with controls within 3 weeks after treatment (p<0.001). CONCLUSIONS: Our results suggest that V9302 monotherapy is insufficient for the treatment of RCC but that a novel combination strategy using CB839 in addition to V9302 could overcome the tolerance for the monotherapy and effectively target glutamine addiction in RCC. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e37 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Yoshinari Muto More articles by this author Akihito Takeuchi More articles by this author Kenji Zennami More articles by this author Eiji Sugihara More articles by this author Ryoichi Shiroki More articles by this author Hideyuki Saya More articles by this author Makoto Sumitomo More articles by this author Expand All Advertisement PDF downloadLoading ...