bims-glucam Biomed News
on Glutamine cancer metabolism
Issue of 2021‒03‒14
seven papers selected by
Sreeparna Banerjee
Middle East Technical University

  1. Neurooncol Adv. 2021 Jan-Dec;3(1):3(1): vdaa149
      Background: Metabolic reprogramming is a common feature in cancer, and it is critical to facilitate cancer cell growth. Isocitrate Dehydrogenase 1/2 (IDH1 and IDH2) mutations (IDHmut) are the most common genetic alteration in glioma grade II and III and secondary glioblastoma and these mutations increase reliance on glutamine metabolism, suggesting a potential vulnerability. In this study, we tested the hypothesis that the brain penetrant glutamine antagonist prodrug JHU-083 reduces glioma cell growth.Material and Methods: We performed cell growth, cell cycle, and protein expression in glutamine deprived or Glutaminase (GLS) gene silenced glioma cells. We tested the effect of JHU-083 on cell proliferation, metabolism, and mTOR signaling in cancer cell lines. An orthotopic IDH1R132H glioma model was used to test the efficacy of JHU-083 in vivo.
    Results: Glutamine deprivation and GLS gene silencing reduced glioma cell proliferation in vitro in glioma cells. JHU-083 reduced glioma cell growth in vitro, modulated cell metabolism, and disrupted mTOR signaling and downregulated Cyclin D1 protein expression, through a mechanism independent of TSC2 modulation and glutaminolysis. IDH1R132H isogenic cells preferentially reduced cell growth and mTOR signaling downregulation. In addition, guanine supplementation partially rescued IDHmut glioma cell growth, mTOR signaling, and Cyclin D1 protein expression in vitro. Finally, JHU-083 extended survival in an intracranial IDH1 mut glioma model and reduced intracranial pS6 protein expression.
    Conclusion: Targeting glutamine metabolism with JHU-083 showed efficacy in preclinical models of IDHmut glioma and measurably decreased mTOR signaling.
    Keywords:  IDH mutation; cell cycle; glioma; glutamine metabolism; mTOR signaling
  2. Methods Mol Biol. 2021 ;2265 91-110
      Glutamine is a major substrate for biosynthesis. It contributes to multiple pathways required for cell proliferation, supports antioxidant defense via glutathione synthesis, and sustains the tricarboxylic acid (TCA) cycle through anaplerosis. Glutamine-fueled anaplerosis and related biosynthesis can be studied in detail in melanoma using stable isotope (13C) labeling followed by gas chromatography-mass spectrometry (GC-MS) analysis of metabolite amounts and labeling. Detailed protocols for the assay of polar metabolites (including amino acids, TCA cycle, and glycolysis metabolites) and fatty acids by these methods following cell treatment with 13C-glutamine or 13C-glucose are presented.
    Keywords:  Amino acids; Fatty acids; GC-MS; Glutamine; Glycolysis; Melanoma; Metabolite quantification; Stable-isotope tracing; Tricarboxylic acid cycle
  3. J Neuropathol Exp Neurol. 2021 Mar 13. pii: nlab018. [Epub ahead of print]
      Medulloblastoma is the most common malignant pediatric brain tumor. Amplification of c-MYC is a hallmark of a subset of poor-prognosis medulloblastoma. MYC upregulates glutamine metabolism across many types of cancer. We modified the naturally occurring glutamine antagonist 6-diazo-5-oxo-l-norleucine (DON) by adding 2 promoeities to increase its lipophilicity and brain penetration creating the prodrug isopropyl 6-diazo-5-oxo-2-(((phenyl (pivaloyloxy) methoxy) - carbonyl) amino) hexanoate, termed JHU395. This prodrug was shown to have a 10-fold improved CSF-to-plasma ratio and brain-to-plasma ratio relative to DON. We hypothesized that JHU395 would have superior cell penetration compared with DON and would effectively and more potently kill MYC-expressing medulloblastoma. JHU395 treatment caused decreased growth and increased apoptosis in multiple human high-MYC medulloblastoma cell lines at lower concentrations than DON. Parenteral administration of JHU395 in Nu/Nu mice led to the accumulation of micromolar concentrations of DON in brain. Treatment of mice bearing orthotopic xenografts of human MYC-amplified medulloblastoma with JHU395 increased median survival from 26 to 45 days compared with vehicle control mice (p < 0.001 by log-rank test). These data provide preclinical justification for the ongoing development and testing of brain-targeted DON prodrugs for use in medulloblastoma.
    Keywords:  6-diazo-5-oxo-l-norleucine; Cancer metabolism; DON; Pediatric brain tumor; Prodrug
  4. Nat Commun. 2021 03 11. 12(1): 1589
      Glutathione peroxidase 4 (GPX4) utilizes glutathione (GSH) to detoxify lipid peroxidation and plays an essential role in inhibiting ferroptosis. As a selenoprotein, GPX4 protein synthesis is highly inefficient and energetically costly. How cells coordinate GPX4 synthesis with nutrient availability remains unclear. In this study, we perform integrated proteomic and functional analyses to reveal that SLC7A11-mediated cystine uptake promotes not only GSH synthesis, but also GPX4 protein synthesis. Mechanistically, we find that cyst(e)ine activates mechanistic/mammalian target of rapamycin complex 1 (mTORC1) and promotes GPX4 protein synthesis at least partly through the Rag-mTORC1-4EBP signaling axis. We show that pharmacologic inhibition of mTORC1 decreases GPX4 protein levels, sensitizes cancer cells to ferroptosis, and synergizes with ferroptosis inducers to suppress patient-derived xenograft tumor growth in vivo. Together, our results reveal a regulatory mechanism to coordinate GPX4 protein synthesis with cyst(e)ine availability and suggest using combinatorial therapy of mTORC1 inhibitors and ferroptosis inducers in cancer treatment.
  5. Technol Health Care. 2021 Feb 15.
      BACKGROUND: The determination of tumor peripheral is of great significance in clinical diagnosis and treatment.OBJECTIVE: In this study, we aim to obtain the metabolic condition in tumor peripheral of gliomas in vivo at 7T.
    METHODS: C6 glioma cells were implanted into the right basal ganglia of Sprague-Dawley (SD) rats under stereotactic guided to create the glioma models. The models were sequentially undergone MRI and MRS examination on an 7T MR scanner designed for animals 7 days after the operation. Neuro metabolites were investigated from the center of the tumor, solid part of the tumor, peritumoral region, and contralateral white matter, and be quantified using the LCmodel software. Glial fibrillary acidic protein (GFAP) immunohistochemistry and conventional hematoxylin and eosin (HE) staining were performed after the imaging protocol.
    RESULTS: Our results found that the inositol (Ins) and taurine (Tau) significantly defected in tumor peripheral compared to both tumor solid and normal tissues (P< 0.05). In contrast, the glutamate and glutamine (Glx) escalated and peaked at the tumor peripheral (P< 0.05).
    CONCLUSIONS: This study revealed that Ins, Tau, and Glx have the potential to provide specific biomarkers for the location of tumor peripheral of glioma.
    Keywords:  Glioma; Magnetic resonance imaging; Magnetic resonance spectroscopy (MRS); tumor metabolism
  6. Mol Ther. 2021 Mar 04. pii: S1525-0016(21)00132-5. [Epub ahead of print]
      An emerging view regarding cancer metabolism is its heterogeneous and context specific, but it remains to be elucidated in breast cancers. Here, we characterized the energy-related metabolic features of breast cancers through integrative analyses of multiple datasets with genomics, transcriptomics, metabolomics and single-cell transcriptome profiling. Energy-related metabolic signatures were used to stratify breast tumors into two prognostic clusters: cluster 1 exhibits high glycolytic activity and decreased survival rate; and the signatures of cluster 2 are enriched in fatty acid oxidation and glutaminolysis. The intertumoral metabolic heterogeneity was reflected by the clustering among three independent large cohorts, and the complexity was further verified at the metabolite level. In addition, we found that the metabolic status of malignant cells rather than that of nonmalignant cells is the major contributor at the single-cell resolution, and its interactions with factors derived from the tumor microenvironment are unanticipated. Notably, among various immune cells and their clusters with distinguishable metabolic features, those with immunosuppressive function presented higher metabolic activities. Collectively, we uncovered the heterogeneity in energy metabolism using a classifier with prognostic and therapeutic value. Single-cell transcriptome profiling provided novel metabolic insights that could ultimately tailor therapeutic strategies based on patient- or cell type-specific cancer metabolism.
    Keywords:  breast cancer; metabolism; single-cell RNA sequencing
  7. Biochem Biophys Res Commun. 2021 Mar 03. pii: S0006-291X(21)00332-6. [Epub ahead of print]549 128-134
      γ-Glutamylcyclotransferase (GGCT) is involved in glutathione homeostasis, in which it catalyzes the reaction that generates 5-oxoproline and free amino acids from γ-glutamyl peptides. Increasing evidence shows that GGCT has oncogenic functions and is overexpressed in various cancer tissues, and that inhibition of GGCT activity exerts anticancer effects in vitro and in vivo. Here, we demonstrate that U83836E ((2R)-2-[[4-(2,6-dipyrrolidin-1-ylpyrimidin-4-yl)piperazin-1-yl]methyl]-3,4-dihydro-2,5,7,8,-tetramethyl-2H-1-benzopyran-6-ol, dihydrochloride), a lazaroid that inhibits lipid peroxidation, inhibits GGCT enzymatic activity. U83836E was identified from a high-throughput screen of low molecular weight compounds using a fluorochrome-conjugated GGCT probe. We directly quantified that U83836E specifically inhibited GGCT by measuring the product of a fluorochrome-conjugated GGCT substrate assay, and showed that U83836E inhibited GGCT activity in extracts of NIH3T3 cells overexpressing GGCT. Moreover, U83836E significantly inhibited tumor growth in a xenograft model that used immunodeficient mice orthotopically inoculated with MCF7 human breast cancer cells. These results indicate that U83836E may be a useful GGCT inhibitor for the development of potential cancer therapeutics.
    Keywords:  MCF7 cells; Tumor growth inhibition; U83836E; Xenograft; γ-Glutamylcyclotransferase