Computational Modeling of A Metabolic Pathway in Ceramide de novo Synthesis

2007 ◽  
Author(s):  
Shobhika Dhingra ◽  
Melissa Freedenberg ◽  
Chang F Quo ◽  
Alfred H. Merrill ◽  
May D Wang
Keyword(s):  
Computational Modeling ◽  
Metabolic Pathway ◽  
De Novo ◽  
De Novo Synthesis

scholarly journals EXTH-04. BLOCKADE OF NRF2/GLUTATHIONE METABOLISM AS A SYNTHETIC LETHALITY APPROACH FOR IDH1-MUTATED GLIOMA

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi83-vi83
Author(s):  
Yang Liu ◽  
Yanxin Lu ◽  
Orieta Celiku ◽  
Aiguo Li ◽  
Chunzhang Yang
Keyword(s):  
Tumor Cell ◽  
Metabolic Pathway ◽  
De Novo ◽  
Synthetic Lethality ◽  
Substantial Reduction ◽  
Lower Grade ◽  
Related Factor ◽  
De Novo Synthesis ◽  
Antioxidant Genes ◽  
Cox Regression Analysis

Abstract BACKGROUND Mutations in isocitrate dehydrogenase (IDH1/2) are frequent genetic abnormalities in human malignancies. IDH1/2-mutated cancers are a recently defined disease entity with distinctive patterns of tumor cell biology, metabolism and resistance to therapy. Molecular targeting approaches against this disease cluster remain limited. METHODS We investigated the redox homeostasis in IDH1 mutant-transduced cells and patient-derived brain tumor initiating cells. The importance of antioxidant genes was confirmed through COX regression analysis on a large cohort of lower grade glioma. We investigated the biologic impact of Nuclear factor erythroid 2-related factor 2 (NRF2) on the glutathione de novo synthesis in IDH1-mutated cells. Finally, we evaluated the value of targeting NRF2/glutathione metabolic pathway as a potential synthetic lethality approach for IDH1-mutated cell in vitro and in vivo. RESULTS We discovered that acquisition of cancer-associated IDH1 mutants results in constitutive activation of NRF2-governed cytoprotective pathways through decoupling of NRF2 from its E3 ligase Kelch-like ECH-associated protein 1. NRF2 mediated the transcriptional activation of GCLC, GCLM and SLC7A11, which strengthens the glutathione de novo synthesis, and relieves the metabolic burden derived from IDH1 mutant neomorphic activity. Blockade of the NRF2/glutathione metabolic pathway synergizes with the elevated intrinsic reactive oxygen species, which results in overwhelming oxidative damage in IDH1-mutated cells, as well as a substantial reduction in tumor cell proliferation and xenograft expansion. CONCLUSION Our findings suggest that blockade of the NRF2/glutathione synthetic pathway is a novel targeting strategy for IDH1-mutated malignancies.

CSIG-02. NRF2-GUIDED GLUTATHIONE SYNTHESIS IS AN ESSENTIAL METABOLIC PATHWAY IN IN IDH1-MUTATED GLIOMA

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi33-vi33
Author(s):  
Yang Liu ◽  
Di Yu ◽  
Chunzhang Yang
Keyword(s):  
Metabolic Pathway ◽  
Nicotinamide Adenine Dinucleotide ◽  
De Novo ◽  
Redox Homeostasis ◽  
Nicotinamide Adenine ◽  
De Novo Synthesis ◽  
Who Grade ◽  
Glutathione Synthesis ◽  
Synergistic Cytotoxicity ◽  
Idh Mutations

Abstract BACKGROUND Isocitrate dehydrogenase (IDH) mutations are common genetic abnormalities in WHO Grade II/III glioma, which result in the reprogramming of cellular metabolism and redox homeostasis. Many lines of evidence showed that IDH mutations are critical for glioma formation, whereas the therapeutic options for IDH-mutated cancers remain limited. METHODS In the present study, we used the patient-derived glioma cell lines to investigate the role of nuclear factor erythroid 2-related factor 2 (NRF2) governed glutathione de novo synthesis. Further, we evaluated the therapeutic value of NRF2 inhibitors in IDH1-mutated cells and preclinical orthotopic models. RESULTS The neomorphic activity of mutant IDH reprogrammed the metabolic pathways involving enzyme cofactors such as nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). The depletion of NAD(P) in IDH1-mutated cells resulted in elevated oxidative stress and constitutive activation of NRF2-governed cytoprotective pathways through the decoupling of NRF2 from its E3 ligase Kelch-like ECH-associated protein 1 (Keap1). Activation of NRF2 enhanced glutathione synthesis by enhancing the gene transcription of GCLC, GCLM, and SLC7A11, which are the critical for glutathione de novo synthesis. Further, evidence from both in vitro assays and patient cohort indicated that NRF2 governed glutathione synthesis is important for maintaining the redox homeostasis and cell survival, especially in IDH1-mutated glioma. Finally, Blockade of the NRF2/glutathione metabolic pathway exhibited synergistic cytotoxicity with the metabolic stress in IDH1-mutated cells, which results in overwhelming oxidative damage, as well as a substantial reduction in tumor cell proliferation and xenograft expansion. CONCLUSION In this study, we highlighted that NRF2 plays critical roles in the disease progression of IDH1-mutated glioma by prompting glutathione synthesis. Targeting NRF2 governed glutathione metabolism could serve as a valuable synthetic lethality approach for IDH1-mutated malignancies.

Characterization of Monocyte-Associated Factor V

1993 ◽  
Vol 70 (02) ◽  
pp. 273-280 ◽  
Author(s):  
Janos Kappelmayer ◽  
Satya P Kunapuli ◽  
Edward G Wyshock ◽  
Robert W Colman
Keyword(s):  
Monoclonal Antibody ◽  
Light Chain ◽  
Peripheral Blood ◽  
De Novo ◽  
Factor V ◽  
Blood Monocytes ◽  
De Novo Synthesis ◽  
Hep G2 ◽  
Hep G2 Cells ◽  
Peripheral Blood Monocytes

SummaryWe demonstrate that in addition to possessing binding sites for intact factor V (FV), unstimulated peripheral blood monocytes also express activated factor V (FVa) on their surfaces. FVa was identified on the monocyte surface by monoclonal antibody B38 recognizing FVa light chain and by human oligoclonal antibodies H1 (to FVa light chain) and H2 (to FVa heavy chain) using immunofluorescence microscopy and flow cytometry. On Western blots, partially cleaved FV could be identified as a 220 kDa band in lysates of monocytes. In addition to surface expression of FVa, monocytes also contain intracellular FV as detected only after permeabilization by Triton X-100 by monoclonal antibody B10 directed specifically to the Cl domain not present in FVa. We sought to determine whether the presence of FV in peripheral blood monocytes is a result of de novo synthesis.Using in situ hybridization, no FV mRNA could be detected in monocytes, while in parallel control studies, factor V mRNA was detectable in Hep G2 cells and CD18 mRNA in monocytes. In addition, using reverse transcriptase and the polymerase chain reaction, no FV mRNA was detected in mononuclear cells or in U937 cells, but mRNA for factor V was present in Hep G2 cells using the same techniques. These data suggest that FV is present in human monocytes, presumably acquired by binding of plasma FV, and that the presence of this critical coagulation factor is not due to de novo synthesis.

Platelets Stimulate Thromboplastin Synthesis in Human Endothelial Cells

1983 ◽  
Vol 49 (02) ◽  
pp. 069-072 ◽  
Author(s):  
U L H Johnsen ◽  
T Lyberg ◽  
K S Galdal ◽  
H Prydz
Keyword(s):  
Endothelial Cells ◽  
De Novo ◽  
Umbilical Vein ◽  
Time Dependent ◽  
De Novo Synthesis ◽  
Human Endothelial Cells ◽  
Tumor Promotor ◽  
Coagulation Assay ◽  
Platelet Aggregates ◽  
Umbilical Vein Endothelial Cells

SummaryHuman umbilical vein endothelial cells in culture synthesize thromboplastin upon stimulation with phytohaemagglutinin (PHA) or the tumor promotor 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The thromboplastin activity is further strongly enhanced in a time dependent reaction by the presence of gel-filtered platelets or platelet aggregates. This effect was demonstrable at platelet concentrations lower than those normally found in plasma, it may thus be of pathophysiological relevance. The thromboplastin activity increased with increasing number of platelets added. Cycloheximide inhibited the increase, suggesting that de novo synthesis of the protein component of thromboplastin, apoprotein III, is necessary.When care was taken to remove monocytes no thromboplastin activity and no apoprotein HI antigen could be demonstrated in suspensions of gel-filtered platelets, platelets aggregated with thrombin or homogenized platelets when studied with a coagulation assay and an antibody neutralization technique.

DE NOVO SYNTHESIS OF STEROIDS BY THE TESTES OF THE HUMAN FOETUS AT MIDGESTATION

1971 ◽  
Vol 68 (1_Supplb) ◽  
pp. S135 ◽  
Author(s):  
R. S. Mathur ◽  
N. Wiqvist ◽  
E. Diczfalusy
Keyword(s):  
De Novo ◽  
De Novo Synthesis ◽  
Human Foetus

In vivo study of the biosynthesis of long-chain fatty acids using deuterated water

1995 ◽  
Vol 269 (2) ◽  
pp. E247-E252 ◽  
Author(s):  
H. O. Ajie ◽  
M. J. Connor ◽  
W. N. Lee ◽  
S. Bassilian ◽  
E. A. Bergner ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
De Novo ◽  
Chain Elongation ◽  
Deuterated Water ◽  
De Novo Synthesis ◽  
Isotopomer Distribution ◽  
Long Chain ◽  
Mass Isotopomer

To determine the contributions of preexisting fatty acid, de novo synthesis, and chain elongation in long-chain fatty acid (LCFA) synthesis, the synthesis of LCFAs, palmitate (16:0), stearate (18:0), arachidate (20:0), behenate (22:0), and lignocerate (24:0), in the epidermis, liver, and spinal cord was determined using deuterated water and mass isotopomer distribution analysis in hairless mice and Sprague-Dawley rats. Animals were given 4% deuterated water for 5 days or 8 wk in their drinking water. Blood was withdrawn at the end of these times for the determination of deuterium enrichment, and the animals were killed to isolate the various tissues for lipid extraction for the determination of the mass isotopomer distributions. The mass isotopomer distributions in LCFA were incompatible with synthesis from a single pool of primer. The synthesis of palmitate, stearate, arachidate, behenate, and lignocerate followed the expected biochemical pathways for the synthesis of LCFAs. On average, three deuterium atoms were incorporated for every addition of an acetyl unit. The isotopomer distribution resulting from chain elongation and de novo synthesis can be described by the linear combination of two binomial distributions. The proportions of preexisting, chain elongation, and de novo-synthesized fatty acids as a percentage of the total fatty acids were determined using multiple linear regression analysis. Fractional synthesis was found to vary, depending on the tissue type and the fatty acid, from 47 to 87%. A substantial fraction (24-40%) of the newly synthesized molecules was derived from chain elongation of unlabeled (recycled) palmitate.

scholarly journals An enzymatic activation of formaldehyde for nucleotide methylation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Charles Bou-Nader ◽  
Frederick W. Stull ◽  
Ludovic Pecqueur ◽  
Philippe Simon ◽  
Vincent Guérineau ◽  
...  
Keyword(s):  
Amino Acids ◽  
Thymidylate Synthase ◽  
Active Site ◽  
De Novo ◽  
Crystallographic Structure ◽  
De Novo Synthesis ◽  
Active Site Residues ◽  
Enzymatic Activation ◽  
Enzyme Cofactors ◽  
Unique Ability

AbstractFolate enzyme cofactors and their derivatives have the unique ability to provide a single carbon unit at different oxidation levels for the de novo synthesis of amino-acids, purines, or thymidylate, an essential DNA nucleotide. How these cofactors mediate methylene transfer is not fully settled yet, particularly with regard to how the methylene is transferred to the methylene acceptor. Here, we uncovered that the bacterial thymidylate synthase ThyX, which relies on both folate and flavin for activity, can also use a formaldehyde-shunt to directly synthesize thymidylate. Combining biochemical, spectroscopic and anaerobic crystallographic analyses, we showed that formaldehyde reacts with the reduced flavin coenzyme to form a carbinolamine intermediate used by ThyX for dUMP methylation. The crystallographic structure of this intermediate reveals how ThyX activates formaldehyde and uses it, with the assistance of active site residues, to methylate dUMP. Our results reveal that carbinolamine species promote methylene transfer and suggest that the use of a CH2O-shunt may be relevant in several other important folate-dependent reactions.

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