bims-glucam Biomed News
on Glutamine cancer metabolism
Issue of 2021‒04‒25
eight papers selected by
Sreeparna Banerjee
Middle East Technical University

  1. Expert Rev Proteomics. 2021 Apr 19. 1-8
      Elucidating the dysregulated metabolic pathways in cancer cells and their relevance to cisplatin resistance could yield new insights into cancer therapy. We previously reported that eight metabolites involved in the tricarboxylic acid (TCA) cycle and glutamine metabolism were associated with platinum-based chemotherapy efficacy in human lung cancer. Here, we investigated the metabolic differences upon cisplatin treatment in lung cancer in vitro and in vivo. A simple and partially validated standard addition method was applied for the quantification of five metabolites involved in the TCA cycle and glutamine metabolism using amide hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS). The present study investigated the levels of these biomarkers in A549 cells and the cisplatin-resistant A549-DDP cells, as well as in the plasma before and after cisplatin treatment in A549 xenograft mice. Levels of five metabolites, including 2-hydroxyglutaric acid (2-HG), α-ketoglutarate (α-KG), succinate, glutamine, and glutamate, showed a decreasing trend in A549-DDP cells. In addition, 2-HG and glutamine were the most significantly altered metabolites in cisplatin-treated A549 xenograft mice. These data indicate that the TCA cycle and glutamine metabolism play important roles in cisplatin-based chemotherapy resistance in lung cancer. Our results provide a new angle for exploring the molecular mechanisms underlying cisplatin resistance.
    Keywords:  Cisplatin resistance; HILIC-MS/MS; TCA cycle; glutamine metabolism; lung cancer
  2. Turk J Haematol. 2021 Apr 22.
      Aim: Low glutamine level has been shown in tumor environment for several cancer subtypes. Therefore, it has been suggested that cancer cells rewire their metabolism to adopt low nutrient level for survival and proliferation. Although glutamine is a non-essential amino acid and can be synthesized de novo, many cancer cells including malignant hematopoietic cells have been indicated to be addicted to glutamine. This study aimed to investigate proliferation of leukemia cell lines in glutamine deprived conditions.Materials and Methods: Cell proliferation of K562, NB-4 and HL-60 cells were determined calculating cell numbers in normal vs low glutamine media. Changes in mRNA expressions were investigated using qRT-PCR. GS encoding GLUL gene was knocked out (KO) in HL-60 cells using CRISPR/Cas9 method, protein expression was evaluated with immunoblotting.
    Results: Proliferation of all cell lines were decreased in glutamine deprived medium. GS protein expression was increased in glutamine limited medium although mRNA level did not change. Increased protein expression was confirmed with inhibition of new protein synthesis by treating cells with cycloheximide. To further investigate the role of GS protein, GS encoding GLUL gene was knocked out (KO) in HL-60 cells using CRISPR/Cas9 method. GS KO cells less proliferated compared to control cells in glutamine limited medium.
    Conclusion: Our results indicates that upregulated GS protein expression is responsible for glutamine addiction of leukemia cell lines. Exploiting the genetic and metabolic mechanisms responsible for GS protein expression could identify new anti-cancer drug targets.
    Keywords:  Crispr/cas9; glutamine limitation; glutamine synthetase; leukemia
  3. Metab Eng. 2021 Apr 01. pii: S1096-7176(21)00053-7. [Epub ahead of print]
      Media and feed optimization have fueled many-fold improvements in mammalian biopharmaceutical production, but genome editing offers an emerging avenue for further enhancing cell metabolism and bioproduction. However, the complexity of metabolism, involving thousands of genes, makes it unclear which engineering strategies will result in desired traits. Here we present a comprehensive pooled CRISPR screen for CHO cell metabolism, including ∼16,000 gRNAs against ∼2500 metabolic enzymes and regulators. Using this screen, we identified a glutamine response network in CHO cells. Glutamine is particularly important since it is often over-fed to drive increased TCA cycle flux, but toxic ammonia may accumulate. With the screen we found one orphan glutamine-responsive gene with no clear connection to our network. Knockout of this novel and poorly characterized lipase, Abhd11, substantially increased growth in glutamine-free media by altering the regulation of the TCA cycle. Thus, the screen provides an invaluable targeted platform to comprehensively study genes involved in any metabolic trait, and elucidate novel regulators of metabolism.
    Keywords:  CHO; CRISPR pooled Screen; Glutamine; Metabolism
  4. G3 (Bethesda). 2019 Jul 01. 9(7): 2061-2070
      The metabolic enzymes that compose glycolysis, the citric acid cycle, and other pathways within central carbon metabolism have emerged as key regulators of animal development. These enzymes not only generate the energy and biosynthetic precursors required to support cell proliferation and differentiation, but also moonlight as regulators of transcription, translation, and signal transduction. Many of the genes associated with animal metabolism, however, have never been analyzed in a developmental context, thus highlighting how little is known about the intersection of metabolism and development. Here we address this deficiency by using the Drosophila TRiP RNAi collection to disrupt the expression of over 1,100 metabolism-associated genes within cells of the eye imaginal disc. Our screen not only confirmed previous observations that oxidative phosphorylation serves a critical role in the developing eye, but also implicated a host of other metabolic enzymes in the growth and differentiation of this organ. Notably, our analysis revealed a requirement for glutamine and glutamate metabolic processes in eye development, thereby revealing a role of these amino acids in promoting Drosophila tissue growth. Overall, our analysis highlights how the Drosophila eye can serve as a powerful tool for dissecting the relationship between development and metabolism.
    Keywords:   Drosophila ; glutamine metabolism; metabolism; mitochondria; oxidative phosphorylation
  5. Cell Metab. 2021 Apr 16. pii: S1550-4131(21)00166-2. [Epub ahead of print]
      Low-protein diets promote metabolic health in rodents and humans, and the benefits of low-protein diets are recapitulated by specifically reducing dietary levels of the three branched-chain amino acids (BCAAs), leucine, isoleucine, and valine. Here, we demonstrate that each BCAA has distinct metabolic effects. A low isoleucine diet reprograms liver and adipose metabolism, increasing hepatic insulin sensitivity and ketogenesis and increasing energy expenditure, activating the FGF21-UCP1 axis. Reducing valine induces similar but more modest metabolic effects, whereas these effects are absent with low leucine. Reducing isoleucine or valine rapidly restores metabolic health to diet-induced obese mice. Finally, we demonstrate that variation in dietary isoleucine levels helps explain body mass index differences in humans. Our results reveal isoleucine as a key regulator of metabolic health and the adverse metabolic response to dietary BCAAs and suggest reducing dietary isoleucine as a new approach to treating and preventing obesity and diabetes.
    Keywords:  FGF21; GCN2; body mass index; branched-chain amino acids; diabetes; insulin resistance; isoleucine; mTORC1; obesity; valine
  6. Nat Cancer. 2021 Mar;2(3): 271-283
      Our understanding of how the RAS protein family, and in particular mutant KRAS promote metabolic dysregulation in cancer cells has advanced significantly over the last decade. In this Review, we discuss the metabolic reprogramming mediated by oncogenic RAS in cancer, and elucidating the underlying mechanisms could translate to novel therapeutic opportunities to target metabolic vulnerabilities in RAS-driven cancers.
    Keywords:  KRAS; autophagy; cancer therapeutics; chemoresistance; ferroptosis; glutaminolysis; glycolysis; macropinocytosis; metabolism
  7. Cell Cycle. 2021 Apr 20. 1-17
      The DNA damage response (DDR) consists of multiple specialized pathways that recognize different insults sustained by DNA and repairs them where possible to avoid the accumulation of mutations. While loss of activity of genes in the DDR has been extensively associated with cancer predisposition and progression, in recent years it has become evident that there is a relationship between the DDR and cellular metabolism. The activity of the metabolic pathways can influence the DDR by regulating the availability of substrates required for the repair process and the function of its players. Additionally, proteins of the DDR can regulate the metabolic flux through the major pathways such as glycolysis, tricarboxylic acid cycle (TCA) and pentose phosphate pathway (PPP) and the production of reactive oxygen species (ROS). This newly discovered connection bears great importance in the biology of cancer and represents a new therapeutic opportunity. Here we describe the nature of the relationship between DDR and metabolism and its potential application in the treatment of cancer. Keywords: DNA repair, metabolism, mitochondria.
    Keywords:  DNA repair; metabolism; mitochondria
  8. Science. 2021 Apr 22. pii: eabd5491. [Epub ahead of print]
      The coenzyme nicotinamide adenine dinucleotide phosphate (NADP+) and its reduced form (NADPH) regulate reductive metabolism in a subcellularly compartmentalized manner. Mitochondrial NADP(H) production depends on the phosphorylation of NAD(H) by NAD kinase 2 (NADK2). Deletion of NADK2 in human cell lines did not alter mitochondrial folate pathway activity, tricarboxylic acid cycle activity, or mitochondrial oxidative stress, but led to impaired cell proliferation in minimal medium. This growth defect was rescued by proline supplementation. NADK2-mediated mitochondrial NADP(H) generation was required for the reduction of glutamate and hence proline biosynthesis. Furthermore, mitochondrial NADP(H) availability determined the production of collagen proteins by cells of mesenchymal lineage. Thus, a primary function of the mitochondrial NADP(H) pool is to support proline biosynthesis for use in cytosolic protein synthesis.