Combinatorial targeting of glutamine metabolism and lysosomal-based lipid metabolism effectively suppresses glioblastoma.

Antipsychotic drugs have been shown to have antitumor effects but have had limited potency in the clinic. Here, we unveil that pimozide inhibits lysosome hydrolytic function to suppress fatty acid and cholesterol release in glioblastoma (GBM), the most lethal brain tumor. Unexpectedly, GBM develops resistance to pimozide by boosting glutamine consumption and lipogenesis. These elevations are driven by SREBP-1, which we find upregulates the expression of ASCT2, a key glutamine transporter. Glutamine, in turn, intensifies SREBP-1 activation through the release of ammonia, creating a feedforward loop that amplifies both glutamine metabolism and lipid synthesis, leading to drug resistance. Disrupting this loop via pharmacological targeting of ASCT2 or glutaminase, in combination with pimozide, induces remarkable mitochondrial damage and oxidative stress, leading to GBM cell death in vitro and in vivo. Our findings underscore the promising therapeutic potential of effectively targeting GBM by combining glutamine metabolism inhibition with lysosome suppression.

Glutaminase 1 plays critical roles in myelodysplastic syndrome and acute myeloid leukemia cells.

BACKGROUND: Myelodysplastic syndrome (MDS) features bone marrow failure and a heightened risk of evolving into acute myeloid leukemia (AML), increasing with age and reducing overall survival. Given the unfavorable outcomes of MDS, alternative treatments are necessary. Glutamine, the most abundant amino acid in the blood, is metabolized first by the enzyme glutaminase (GLS). OBJECTIVES: To investigate whether GLS is involved in the progression of MDS. The efficacy of GLS inhibitors (CB839 or IPN60090) and BCL2 inhibitor venetoclax was also examined. METHODS: We employed GLS inhibitors (CB839, IPN60090) and the BCL2 inhibitor venetoclax, prepared as detailed. MDS and AML cell lines were cultured under standard and modified (hypoxic, glutamine-free) conditions. Viability, proliferation, and caspase activity were assessed with commercial kits. RT-PCR quantified gene expression post-shRNA transfection. Mitochondrial potential, ATP levels, proteasome activity, and metabolic functions were evaluated using specific assays. Statistical analyses (t-tests, ANOVA) validated the findings. RESULTS: The glutamine-free medium inhibited the growth of MDS cells. GLS1 expression was higher in AML cells than in normal control samples (GSE15061), whereas GLS2 expression was not. Treatment of MDS and AML cells for 72 h was inhibited in a dose-dependent manner by GLS inhibitors. Co-treatment with the B-cell lymphoma 2 (BCL2) inhibitor venetoclax and GLS inhibitors increased potency. Cells transfected with GLS1 short hairpin RNA showed suppressed proliferation under hypoxic conditions and increased sensitivity to venetoclax. CONCLUSIONS: Targeting glutaminolysis and BCL2 inhibition enhances the therapeutic efficacy and has been proposed as a novel strategy for treating high-risk MDS and AML.

The unique catalytic properties of PSAT1 mediate metabolic adaptation to glutamine blockade.

Cultured cancer cells frequently rely on the consumption of glutamine and its subsequent hydrolysis by glutaminase (GLS). However, this metabolic addiction can be lost in the tumour microenvironment, rendering GLS inhibitors ineffective in the clinic. Here we show that glutamine-addicted breast cancer cells adapt to chronic glutamine starvation, or GLS inhibition, via AMPK-mediated upregulation of the serine synthesis pathway (SSP). In this context, the key product of the SSP is not serine, but α-ketoglutarate (α-KG). Mechanistically, we find that phosphoserine aminotransferase 1 (PSAT1) has a unique capacity for sustained α-KG production when glutamate is depleted. Breast cancer cells with resistance to glutamine starvation or GLS inhibition are highly dependent on SSP-supplied α-KG. Accordingly, inhibition of the SSP prevents adaptation to glutamine blockade, resulting in a potent drug synergism that suppresses breast tumour growth. These findings highlight how metabolic redundancy can be context dependent, with the catalytic properties of different metabolic enzymes that act on the same substrate determining which pathways can support tumour growth in a particular nutrient environment. This, in turn, has practical consequences for therapies targeting cancer metabolism.

Aerobic glycolysis but not GLS1-dependent glutamine metabolism is critical for anti-tumor immunity and response to checkpoint inhibition.

Tumor cells undergo uncontrolled proliferation driven by enhanced anabolic metabolism including glycolysis and glutaminolysis. Targeting these pathways to inhibit cancer growth is a strategy for cancer treatment. Critically, however, tumor-responsive T cells share metabolic features with cancer cells, making them susceptible to these treatments as well. Here, we assess the impact on anti-tumor T cell immunity and T cell exhaustion by genetic ablation of lactate dehydrogenase A (LDHA) and glutaminase1 (GLS1), key enzymes in aerobic glycolysis and glutaminolysis. Loss of LDHA severely impairs expansion of T cells in response to tumors and chronic infection. In contrast, T cells lacking GLS1 can compensate for impaired glutaminolysis by engaging alternative pathways, including upregulation of asparagine synthetase, and thus efficiently respond to tumor challenge and chronic infection as well as immune checkpoint blockade. Targeting GLS1-dependent glutaminolysis, but not aerobic glycolysis, may therefore be a successful strategy in cancer treatment, particularly in combination with immunotherapy.

Glutaminase-1 inhibition alleviates senescence of Wharton's jelly-derived mesenchymal stem cells via senolysis.

Replicative senescence of mesenchymal stem cells (MSCs) caused by repeated cell culture undermines their potential as a cell therapy because of the reduction in their proliferation and therapeutic potential. Glutaminase-1 (GLS1) is reported to be involved in the survival of senescent cells, and inhibition of GLS1 alleviates age-related dysfunction via senescent cell removal. In the present study, we attempted to elucidate the association between MSC senescence and GLS1. We conducted in vitro and in vivo experiments to analyze the effect of GLS1 inhibition on senolysis and the therapeutic effects of MSCs. Inhibition of GLS1 in Wharton's jelly-derived MSCs (WJ-MSCs) reduced the expression of aging-related markers, such as p16, p21, and senescence-associated secretory phenotype genes, by senolysis. Replicative senescence-alleviated WJ-MSCs, which recovered after short-term treatment with bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl)ethyl sulfide 3 (BPTES), showed increased proliferation and therapeutic effects compared to those observed with senescent WJ-MSCs. Moreover, compared to senescent WJ-MSCs, replicative senescence-alleviated WJ-MSCs inhibited apoptosis in serum-starved C2C12 cells, enhanced muscle formation, and hindered apoptosis and fibrosis in mdx mice. These results imply that GLS1 inhibition can ameliorate the therapeutic effects of senescent WJ-MSCs in patients with muscle diseases such as Duchenne muscular dystrophy. In conclusion, GLS1 is a key factor in modulating the senescence mechanism of MSCs, and regulation of GLS1 may enhance the therapeutic effects of senescent MSCs, thereby increasing the success rate of clinical trials involving MSCs.

CB-839 induces reversible dormancy in lung tumor-cells.

Glutaminase inhibitors are currently being explored as potential treatments for cancer. This study aimed to elucidate the molecular mechanisms underlying the effects of CB-839 on lung tumor cell lines compared to non-tumor cell lines. Viability assays based on NADPH-dependent dehydrogenases activity, ATP energy production, or mitochondrial reductase activity were used to determine that CB-839 caused significant tumor cell specific inhibition of cellular functions. Clonogenic survival assay revealed a dose dependent reduction in clonogenic survival of various lung tumor cells presenting estimated IC50 values between 10 and 90 nM, while no effect on non-tumor cells was observed. CB-839 led to a 20% reduction in glutaminase (GLS1, a mitochondrial enzyme that catalyzes the conversion of glutamine to glutamate) activity, and a dose-dependent reduced glutamine consumption in tumor cells and had no effect on non-tumor cells. Cell cycle analysis showed the CB-839 did not lead to cell cycle arrest. Apoptosis and necrosis assays revealed an only slight increase in apoptosis in tumor cells. Furthermore, a trypan blue exclusion assay revealed about 40% growth reduction in tumor cells at 0.1-1 µM CB-839 treatment. Surprisingly, treated cells resumed normal growth when re-plated in a drug-free medium, demonstrating reversibility. In hypoxic conditions, CB-839's effect on clonogenic survival was amplified in a dose dependent manner consistent with increased role of GLS1 for energy production under hypoxic conditions. In conclusion, these results suggest CB-839 efficacy is linked to temporary and reversible reduction in glutamine utilization suggesting induction of dormancy.

Targeting amino acid-metabolizing enzymes for cancer immunotherapy.

Despite the immune system's role in the detection and eradication of abnormal cells, cancer cells often evade elimination by exploitation of various immune escape mechanisms. Among these mechanisms is the ability of cancer cells to upregulate amino acid-metabolizing enzymes, or to induce these enzymes in tumor-infiltrating immunosuppressive cells. Amino acids are fundamental cellular nutrients required for a variety of physiological processes, and their inadequacy can severely impact immune cell function. Amino acid-derived metabolites can additionally dampen the anti-tumor immune response by means of their immunosuppressive activities, whilst some can also promote tumor growth directly. Based on their evident role in tumor immune escape, the amino acid-metabolizing enzymes glutaminase 1 (GLS1), arginase 1 (ARG1), inducible nitric oxide synthase (iNOS), indoleamine 2,3-dioxygenase 1 (IDO1), tryptophan 2,3-dioxygenase (TDO) and interleukin 4 induced 1 (IL4I1) each serve as a promising target for immunotherapeutic intervention. This review summarizes and discusses the involvement of these enzymes in cancer, their effect on the anti-tumor immune response and the recent progress made in the preclinical and clinical evaluation of inhibitors targeting these enzymes.

Microbial-derived Urolithin A Targets GLS1 to Inhibit Glutaminolysis and Attenuate Cirrhotic Portal Hypertension.

BACKGROUND & AIMS: Cirrhotic portal hypertension (CPH) is the leading cause of mortality in patients with cirrhosis. Over 50% of patients with CPH treated with current clinical pharmacotherapy still present variceal bleeding or sometimes death owing to insufficient reduction in portal pressure. Elevated intrahepatic vascular resistance (IHVR) plays a fundamental role in increasing portal pressure. Because of its potent effect in reducing portal pressure and maintaining normal portal inflow to preserve liver function, lowering the IHVR is acknowledged as an optimal anti-CPH strategy but without clinical drugs. We aimed to investigate the protective effect of microbial-derived Urolithin A (UroA) in IHVR and CPH. METHODS: Carbon tetrachloride or bile duct ligation surgery was administered to mice to induce liver fibrosis and CPH. 16S rRNA gene sequencing was used for microbial analysis. Transcriptomics and metabolomics analyses were employed to study the host and cell responses. RESULTS: UroA was remarkably deficient in patients with CPH and was negatively correlated with disease severity. UroA deficiency was also confirmed in CPH mice and was associated with a reduced abundance of UroA-producing bacterial strain (Lactobacillus murinus, L. murinus). Glutaminolysis of hepatic stellate cells (HSCs) was identified as a previously unrecognized target of UroA. UroA inhibited the activity of glutaminase1 to suppress glutaminolysis, which counteracted fibrogenesis and contraction of HSCs and ameliorated CPH by relieving IHVR. Supplementation with UroA or L. murinus effectively ameliorated CPH in mice. CONCLUSIONS: We for the first time identify the deficiency of gut microbial metabolite UroA as an important cause of CPH. We demonstrate that UroA exerts an excellent anti-CPH effect by suppressing HSC glutaminolysis to lower the IHVR, which highlighted its great potential as a novel therapeutic agent for CPH.

HuR controls glutaminase RNA metabolism.

Glutaminase (GLS) is directly related to cell growth and tumor progression, making it a target for cancer treatment. The RNA-binding protein HuR (encoded by the ELAVL1 gene) influences mRNA stability and alternative splicing. Overexpression of ELAVL1 is common in several cancers, including breast cancer. Here we show that HuR regulates GLS mRNA alternative splicing and isoform translation/stability in breast cancer. Elevated ELAVL1 expression correlates with high levels of the glutaminase isoforms C (GAC) and kidney-type (KGA), which are associated with poor patient prognosis. Knocking down ELAVL1 reduces KGA and increases GAC levels, enhances glutamine anaplerosis into the TCA cycle, and drives cells towards glutamine dependence. Furthermore, we show that combining chemical inhibition of GLS with ELAVL1 silencing synergistically decreases breast cancer cell growth and invasion. These findings suggest that dual inhibition of GLS and HuR offers a therapeutic strategy for breast cancer treatment.

Metabolic vulnerabilities in cancer: A new therapeutic strategy.

Cancer metabolism is now a key area for therapeutic intervention, targeting unique metabolic reprogramming crucial for tumor growth and survival. This article reviews the therapeutic potential of addressing metabolic vulnerabilities through glycolysis and glutaminase inhibitors, which disrupt cancer cell metabolism. Challenges such as tumor heterogeneity and adaptive resistance are discussed, with strategies including personalized medicine and predictive biomarkers to enhance treatment efficacy. Additionally, integrating diet and lifestyle changes with metabolic targeting underscores a holistic approach to improving therapy outcomes. The article also examines the benefits of incorporating these strategies into standard care, highlighting the potential for more tailored, safer treatments. In conclusion, exploiting metabolic vulnerabilities promises a new era in oncology, positioning metabolic targeting at the forefront of personalized cancer therapy and transforming patient care.

Curcumin synergistically enhances the efficacy of gemcitabine against gemcitabine-resistant cholangiocarcinoma via the targeting LAT2/glutamine pathway.

Cholangiocarcinoma (CCA) is often diagnosed late, leading to incomplete tumor removal, drug resistance and reduced chemotherapy efficacy. Curcumin has the potential for anti-cancer activity through various therapeutic properties and can improve the efficacy of chemotherapy. We aimed to investigate the synergistic effect of a combination of curcumin and gemcitabine against CCA, targeting the LAT2/glutamine pathway. This combination synergistically suppressed proliferation in gemcitabine-resistant CCA cells (KKU-213BGemR). It also resulted in a remarkable degree of CCA cell apoptosis and cell cycle arrest, characterized by a high proportion of cells in the S and G2/M phases. Knockdown of SLC7A8 decreased the expressions of glutaminase and glutamine synthetase, resulting in inhibited cell proliferation and sensitized CCA cells to gemcitabine treatment. Moreover, in vivo experiments showed that a combination curcumin and gemcitabine significantly reduced tumor size, tumor growth rate and LAT2 expression in a gemcitabine-resistant CCA xenograft mouse model. Suppression of tumor progression in an orthotopic CCA hamster model provided strong support for clinical application. In conclusion, curcumin synergistically enhances gemcitabine efficacy against gemcitabine-resistant CCA by induction of apoptosis, partly via inhibiting LAT2/glutamine pathway. This approach may be an alternative strategy for the treatment of gemcitabine-resistant in CCA patients.

The combined inhibition of SLC1A3 and glutaminase in osimertinib-resistant EGFR mutant cells.

BACKGROUND: We investigated the unknown mechanisms of osimertinib-resistant EGFR-mutant lung cancer. METHODS: An osimertinib-resistant cell line (PC-9/OsmR2) was established through continuous exposure to osimertinib using an EGFR exon 19 deletion (19Del) lung adenocarcinoma cell line (PC-9). EGFR 19Del (M1), L858R/T790M/C797S (M6), and L858R/C797S (M8) expression vectors were introduced into Ba/F3 cells. A second osimertinib-resistant line (M1/OsmR) was established through continuous exposure to osimertinib using M1 cells. RESULTS: SLC1A3 had the highest mRNA expression level in PC-9/OsmR2 compared to PC-9 cells by microarray analysis and SLC1A3 was increased by flow cytometry. In PC-9/OsmR2 cells, osimertinib sensitivity was significantly increased in combination with siSLC1A3. Because SLC1A3 functions in glutamic acid transport, osimertinib with a glutaminase inhibitor (CB-839) or an SLC1A3 inhibitor (TFB-TBOA) increased the sensitivity. Also, CB-839 plus TFB-TBOA without osimertinib resulted in greater susceptibility than did CB-839 or TFB-TBOA plus osimertinib. Comprehensive metabolome analysis showed that the M1/OsmR cells had significantly more glutamine and glutamic acid than M1 cells. CB-839 plus osimertinib exerted a synergistic effect on M6 cells and an additive effect on M8 cells. CONCLUSION: Targeting glutaminase and glutamic acid may overcome the osimertinib-resistant EGFR-mutant lung cancer.

Glutamine metabolism improves left ventricular function but not macrophage-mediated inflammation following myocardial infarction.

Glutamine is a critical amino acid that serves as an energy source, building block, and signaling molecule for the heart tissue and the immune system. However, the role of glutamine metabolism in regulating cardiac remodeling following myocardial infarction (MI) is unknown. In this study, we show in adult male mice that glutamine metabolism is altered both in the remote (contractile) area and in infiltrating macrophages in the infarct area after permanent left anterior descending artery occlusion. We found that metabolites related to glutamine metabolism were differentially altered in macrophages at days 1, 3, and 7 after MI using untargeted metabolomics. Glutamine metabolism in live cells was increased after MI relative to no MI controls. Gene expression in the remote area of the heart indicated a loss of glutamine metabolism. Glutamine administration improved left ventricle (LV) function at days 1, 3, and 7 after MI, which was associated with improved contractile and metabolic gene expression. Conversely, administration of BPTES, a pharmacological inhibitor of glutaminase-1, worsened LV function after MI. Neither glutamine nor BPTES administration impacted gene expression or bioenergetics of macrophages isolated from the infarct area. Our results indicate that glutamine metabolism plays a critical role in maintaining LV contractile function following MI and that glutamine administration improves LV function. Glutamine metabolism may also play a role in regulating macrophage function, but macrophages are not responsive to exogenous pharmacological manipulation of glutamine metabolism.NEW & NOTEWORTHY Glutamine metabolism is altered in both infarct macrophages and the remote left ventricle (LV) following myocardial infarction (MI). Supplemental glutamine improves LV function following MI while inhibiting glutamine metabolism with BPTES worsens LV function. Supplemental glutamine or BPTES does not impact macrophage immunometabolic phenotypes after MI.

SIRT4 Has an Anti-Cancer Role in Cervical Cancer by Inhibiting Glutamine Metabolism via the MEK/ERK/C-Myc Axis.

BACKGROUND/AIM: Glutamine metabolism is crucial in cell proliferation, aging, and apoptosis across various cancer types. Existing research indicates that Sirtuin 4 (SIRT4), primarily located in mitochondria, modulates this process. This study aimed to clarify the regulatory relationship between SIRT4 and glutamine metabolism in cervical cancer. MATERIALS AND METHODS: SIRT4 mRNA levels and their clinical correlation to cervical cancer were analyzed using the UALCAN database. Immunohistochemistry (IHC) was performed to assess SIRT4 protein expression in tissue samples from cervical cancer patients. Transient transfection was employed to create Hela and Siha cell lines with overexpressed SIRT4, mitogen-activated extracellular signal-regulated kinase (MEK), and glutaminase 1 (GLS1). The impact on cellular functions was studied using MTT, soft agar, transwell, and western blotting assays. Glutamate and ATP levels were also measured to evaluate metabolic changes. RESULTS: Low levels of SIRT4 mRNA in cervical cancer tissues correlated with tumor metastasis and poor survival rates. Overexpression of SIRT4 led to suppressed cell proliferation, colony growth, and motility, along with significant down-regulation of GLS expression, a key contributor to glutamine metabolism. Additionally, SIRT4 overexpression resulted in the inactivation of the MEK/ERK/c-myc signaling pathway, while overexpression of MEK reversed these effects. Notably, the inhibitory effects of SIRT4 on cell proliferation, colony formation, migration, and invasion in Hela and Siha cells were significantly attenuated following GLS1 overexpression. CONCLUSION: SIRT4 acts as an anti-cancer agent in cervical cancer by inhibiting glutamine metabolism through the MEK/ERK/c-myc signaling pathway, providing a novel sight for cervical cancer therapy.

The potential therapeutic targets of glutamine metabolism in head and neck squamous cell carcinoma.

Targeting metabolic reprogramming may be an effective strategy to enhance cancer treatment efficacy. Glutamine serves as a vital nutrient for cancer cells. Inhibiting glutamine metabolism has shown promise in preventing tumor growth both in vivo and in vitro through various mechanisms. Therefore, this review collates recent scientific literature concerning the correlation between glutamine metabolism and cancer treatment. Novel treatment modalities based on amino acid transporters, metabolites, and glutaminase are discussed. Moreover, we demonstrate the relationship between glutamine metabolism and tumor proliferation, drug resistance, and the tumor immune microenvironment, offering new perspectives for the clinical treatment of head and neck squamous cell carcinoma, particularly for combined therapies. Identifying innovative approaches for enhancing the efficacy of glutamine-based metabolic therapy is crucial to improving HNSCC treatment.

Analysis of anti-tumor effect and mechanism of GLS1 inhibitor CB-839 in colorectal cancer using a stroma-abundant tumor model.

BACKGROUND: Glutaminase 1 (GLS1), a key enzyme in glutamine metabolism in cancer cells, acts as a tumor promoter and could be a potential therapeutic target. CB-839, a GLS1-specific inhibitor, was developed recently. Herein, we aimed to elucidate the anti-tumor effects and mechanism of action of CB-839 in colorectal cancer (CRC). METHODS: Using the UCSC Xena public database, we evaluated GLS1 expression in various cancers. Immunostaining for GLS1 was performed on 154 surgically resected human CRC specimens. Subsequently, we examined the GLS1 mRNA expression levels in eight CRC cell lines and evaluated the association between GLS1 expression and CB-839 efficacy. To create a reproducible CRC model with abundant stroma and an allogeneic immune response, we co-transplanted CT26 and stem cells into BALB/c mice and treated them with CB-839. Finally, RNA sequencing of mouse tumors was performed. RESULTS: Database analysis showed higher GLS1 expression in CRC tissues than in normal colon tissues. Clinical samples from 114 of the 154 patients with CRC showed positive GLS1 expression. GLS1 expression in clinical CRC tissues correlated with vascular invasion. CB-839 treatment inhibited cancer cell proliferation depending on GLS1 expression in vitro and inhibited tumor growth and metastasis in the CRC mouse model. RNA sequencing revealed that CB-839 treatment inhibited stromal activation, tumor growth, migration, and angiogenesis. These findings were validated through in vitro and in vivo experiments and clinical specimen analysis. CONCLUSIONS: GLS1 expression in CRC plays important roles in tumor progression. CB-839 has inhibitory effects on cancer proliferation and the tumor microenvironment.

Biomimetic copper-doped polypyrrole nanoparticles induce glutamine metabolism inhibition to enhance breast cancer cuproptosis and immunotherapy.

Cuproptosis, a newly discovered mechanism of inducing tumor cell death, primarily relies on the intracellular accumulation of copper ions. The utilization of Cu-based nanomaterials to induce cuproptosis holds promising prospects in future biomedical applications. However, the presence of high levels of glutathione (GSH) within tumor cells hinders the efficacy of cuproptosis. In this study, we have developed a BPTES-loaded biomimetic Cu-doped polypyrrole nanoparticles (CuP) nanosystem (PCB) for enhanced cuproptosis and immune modulation. PCB comprises an internal BPTES and CuP core and an external platelet membrane (PM) that facilitates active targeting to tumor sites following intravenous administration. Subsequently, PCB effectively suppresses glutaminase (GLS1) activity, thereby reducing GSH content. Moreover, CuP catalyze intracellular H2O2, amplifying oxidative stress while simultaneously inducing dihydrolipoyl transacetylase (DLAT) oligomerization through released Cu2+, resulting in cuproptosis. PCB not only inhibits primary tumors but also exhibits inhibitory effects on abscopal tumors. This work represents the first instance where GLS inhibition has been employed to enhance cuproptosis and immunotherapy. It also provides valuable insights into further investigations on cuproptosis.

Targeting the glutamine metabolism to suppress cell proliferation in mesenchymal docetaxel-resistant prostate cancer.

Docetaxel (DX) serves as a palliative treatment option for metastatic prostate cancer (PCa). Despite initial remission, acquired DX resistance is inevitable. The mechanisms behind DX resistance have not yet been deciphered, but a mesenchymal phenotype is associated with DX resistance. Mesenchymal phenotypes have been linked to metabolic rewiring, obtaining most ATP production by oxidative phosphorylation (OXPHOS) powered substantially by glutamine (Gln). Likewise, Gln is known to play an essential role in modulating bioenergetic, redox homeostasis and autophagy. Herein, investigations of Gln deprivation on DX-sensitive and -resistant (DR) PCa cells revealed that the DR cell sub-lines were susceptible to Gln deprivation. Mechanistically, Gln deprivation reduced OXPHOS and ATP levels, causing a disturbance in cell cycle progression. Genetic and chemical inhibition of the Gln-metabolism key protein GLS1 could validate the Gln deprivation results, thereby representing a valid therapeutic target. Moreover, immunohistological investigation of GLS1 revealed a high-expressing GLS1 subgroup post-docetaxel failure, exhibiting low overall survival. This subgroup presents an intriguing opportunity for targeted therapy focusing on glutamine metabolism. Thus, these findings highlight a possible clinical rationale for the chemical inhibition of GLS1 as a therapeutic strategy to target mesenchymal DR PCa cells, thereby delaying accelerated tumour progression.

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.

Glutamine Metabolism Heterogeneity in Glioblastoma Unveils an Innovative Combination Therapy Strategy.

Treatment of glioblastoma multiforme (GBM) remains challenging. Unraveling the orchestration of glutamine metabolism may provide a novel viewpoint on GBM therapy. The study presented a full and comprehensive comprehending of the glutamine metabolism atlas and heterogeneity in GBM for facilitating the development of a more effective therapeutic choice. Transcriptome data from large GBM cohorts were integrated in this study. A glutamine metabolism-based classification was established through consensus clustering approach, and a classifier by LASSO analysis was defined for differentiating the classification. Prognosis, signaling pathway activity, tumor microenvironment, and responses to immune checkpoint blockade (ICB) and small molecular drugs were characterized in each cluster. A combinational therapy of glutaminase inhibitor CB839 with dihydroartemisinin (DHA) was proposed, and the influence on glutamine metabolism, apoptosis, reactive oxygen species (ROS), and migration was measured in U251 and U373 cells. We discovered that GBM presented heterogeneous glutamine metabolism-based clusters, with unique survival outcomes, activity of signaling pathways, tumor microenvironment, and responses to ICB and small molecular compounds. In addition, the classifier could accurately differentiate the two clusters. Strikingly, the combinational therapy of CB839 with DHA synergistically attenuated glutamine metabolism, triggered apoptosis and ROS accumulation, and impaired migrative capacity in GBM cells, demonstrating the excellent preclinical efficacy. Altogether, our findings unveil the glutamine metabolism heterogeneity in GBM and propose an innovative combination therapy of CB839 with DHA for this malignant disease.