TAMI-37. STEAROYL-COA DESATURASE 1 IS ESSENTIAL FOR THE GROWTH OF IDH MUTANT GLIOMA

Abstract BACKGROUND Increased de novo lipogenesis is a hallmark of cancer metabolism. In this study, we interrogated the role of de novo lipogenesis in IDH1 mutated glioma’s growth and identified the key enzyme, Stearoyl-CoA desaturase 1 (SCD1) that provides this growth advantage. MATERIALS ANDMETHODS We prepared genetically engineered glioma cell lines (U251 wild-type: U251WT and U251 IDHR132H mutant: U251RH) and normal human astrocytes (empty vector induced-NHA: NHAEV and IDHR132H mutant: NHARH). Lipid metabolic analysis was conducted by using LC-MS and Raman imaging microscopy. SCD1 expression was investigated by The Cancer Genome Atlas (TCGA) data analysis and Western-blotting method. Knock-out of SCD1 was conducted by using CRISPR/Cas9 and shRNA. RESULTS Previously, we showed that IDH1 mut glioma cells have increased monounsaturated fatty acids (MUFAs). TCGA data revealed IDH mut glioma shows significantly higher SCD1 mRNA expression than wild-type glioma. Our model systems of IDH1 mut (U251RH, NHARH) showed increased expression of this enzyme compared with their wild-type counterpart. Moreover, addition of D-2HG to U251WT increased SCD1 expression. Herein, we showed that inhibition of SCD1 with CAY10566 decreased relative cell number and sphere forming capacity in a dose-dependent manner. Furthermore, addition of MUFAs were able to rescue the SCD1 inhibitor induced-cell death and sphere forming capacity. Knock out of SCD1 revealed decreased cell proliferation and sphere forming ability. Decreasing lipid content from the media did not alter the growth of these cells, suggesting that glioma cells rely on de novo lipid synthesis rather than scavenging them from the microenvironment. CONCLUSION Overexpression of IDH mutant gene altered lipid composition in U251 cells to enrich MUFA levels and we confirmed that D-2HG caused SCD1 upregulation in U251WT. We demonstrated the glioma cell growth requires SCD1 expression and the results of the present study may provide novel insights into the role of SCD1 in IDH mut gliomas growth.

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249 ROLE OF DE NOVO LIPOGENESIS IN GROWING VERY LOW BIRTH WEIGHT BREASTFED INFANTS.

Journal of Investigative Medicine ◽

10.1136/jim-52-suppl1-249 ◽

2004 ◽

Vol 52 (Suppl 1) ◽

pp. S122.6-S123

Author(s):

M. Garg ◽

C. Bell ◽

L. Rogers ◽

S. Bassilian ◽

W. N.P. Lee

Keyword(s):

Birth Weight ◽

Low Birth Weight ◽

Very Low Birth Weight ◽

De Novo ◽

De Novo Lipogenesis ◽

Breastfed Infants

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Impaired eIF5A function causes a Mendelian disorder that is partially rescued in model systems by spermidine

Nature Communications ◽

10.1038/s41467-021-21053-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Víctor Faundes ◽

Martin D. Jennings ◽

Siobhan Crilly ◽

Sarah Legraie ◽

Sarah E. Withers ◽

...

Keyword(s):

De Novo ◽

Model Systems ◽

Yeast Growth ◽

Related Disorder ◽

Optimal Position ◽

Human Phenotype ◽

Mendelian Disorder ◽

Growth Defects ◽

Polysome Profiling

AbstractThe structure of proline prevents it from adopting an optimal position for rapid protein synthesis. Poly-proline-tract (PPT) associated ribosomal stalling is resolved by highly conserved eIF5A, the only protein to contain the amino acid hypusine. We show that de novo heterozygous EIF5A variants cause a disorder characterized by variable combinations of developmental delay, microcephaly, micrognathia and dysmorphism. Yeast growth assays, polysome profiling, total/hypusinated eIF5A levels and PPT-reporters studies reveal that the variants impair eIF5A function, reduce eIF5A-ribosome interactions and impair the synthesis of PPT-containing proteins. Supplementation with 1 mM spermidine partially corrects the yeast growth defects, improves the polysome profiles and restores expression of PPT reporters. In zebrafish, knockdown eif5a partly recapitulates the human phenotype that can be rescued with 1 µM spermidine supplementation. In summary, we uncover the role of eIF5A in human development and disease, demonstrate the mechanistic complexity of EIF5A-related disorder and raise possibilities for its treatment.

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A Narrative Review on the Role of AMPK on De Novo Lipogenesis in Non-Alcoholic Fatty Liver Disease: Evidence from Human Studies

Cells ◽

10.3390/cells10071822 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1822

Author(s):

Christian von Loeffelholz ◽

Sina M. Coldewey ◽

Andreas L. Birkenfeld

Keyword(s):

Liver Disease ◽

Fatty Liver ◽

Fatty Liver Disease ◽

Mammalian Cells ◽

De Novo ◽

Adenosine Monophosphate ◽

De Novo Lipogenesis ◽

Alcoholic Fatty Liver ◽

Alcoholic Fatty Liver Disease

5′AMP-activated protein kinase (AMPK) is known as metabolic sensor in mammalian cells that becomes activated by an increasing adenosine monophosphate (AMP)/adenosine triphosphate (ATP) ratio. The heterotrimeric AMPK protein comprises three subunits, each of which has multiple phosphorylation sites, playing an important role in the regulation of essential molecular pathways. By phosphorylation of downstream proteins and modulation of gene transcription AMPK functions as a master switch of energy homeostasis in tissues with high metabolic turnover, such as the liver, skeletal muscle, and adipose tissue. Regulation of AMPK under conditions of chronic caloric oversupply emerged as substantial research target to get deeper insight into the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Evidence supporting the role of AMPK in NAFLD is mainly derived from preclinical cell culture and animal studies. Dysbalanced de novo lipogenesis has been identified as one of the key processes in NAFLD pathogenesis. Thus, the scope of this review is to provide an integrative overview of evidence, in particular from clinical studies and human samples, on the role of AMPK in the regulation of primarily de novo lipogenesis in human NAFLD.

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Enhancement of radiosensitivity of wild-type p53 human glioma cells by adenovirus-mediated delivery of the p53 gene

Journal of Neurosurgery ◽

10.3171/jns.1998.89.1.0125 ◽

1998 ◽

Vol 89 (1) ◽

pp. 125-132 ◽

Cited By ~ 54

Author(s):

Frederick F. Lang ◽

W. K. Alfred Yung ◽

Uma Raju ◽

Floralyn Libunao ◽

Nicholas H. A. Terry ◽

...

Keyword(s):

Cell Line ◽

Glioma Cell ◽

Radiation Treatment ◽

P53 Protein ◽

Glioma Cells ◽

Glioma Cell Line ◽

Wild Type ◽

Content Type ◽

Infected Cells ◽

Fine Print

Object. The authors sought to determine whether combining p53 gene transfer with radiation therapy would enhance the therapeutic killing of p53 wild-type glioma cells. It has been shown in several reports that adenovirus-mediated delivery of the p53 gene into p53 mutant gliomas results in dramatic apoptosis, but has little effect on gliomas containing wild-type p53 alleles. Therefore, p53 gene therapy alone may not be a clinically effective treatment for gliomas because most gliomas are composed of both p53 mutant and wild-type cell populations. One potential approach to overcome this problem is to exploit the role p53 plays as an important determinant in the cellular response to ionizing radiation. Methods. In vitro experiments were performed using the glioma cell line U87MG, which contains wild-type p53. Comparisons were made to the glioma cell line U251MG, which contains a mutant p53 allele. Monolayer cultures were infected with an adenovirus containing wild-type p53 (Ad5CMV-p53), a control vector (dl312), or Dulbecco's modified Eagle's medium (DMEM). Two days later, cultures were irradiated and colony-forming efficiency was determined. Transfection with p53 had only a minor effect on the plating efficiency of nonirradiated U87MG cells, reducing the plating efficiency from 0.23 ± 0.01 in DMEM to 0.22 ± 0.04 after addition of Ad5CMV-p53. However, p53 transfection significantly enhanced the radiosensitivity of these cells. The dose enhancement factor at a surviving fraction of 0.10 was 1.5, and the surviving fraction at 2 Gy was reduced from 0.61 in untransfected controls to 0.38 in p53-transfected cells. Transfection of the viral vector control (dl312) had no effect on U87MG radiosensitivity. In comparison, transfection of Ad5CMV-p53 into the p53 mutant cell line U251MG resulted in a significant decrease in the surviving fraction of these cells compared with controls, and no radiosensitization was detected. To determine whether Ad5CMV-p53—mediated radiosensitization of U87MG cells involved an increase in the propensity of these cells to undergo apoptosis, flow cytometric analysis of terminal deoxynucleotidyl transferase-mediated biotinylated-deoxyuridinetriphosphate nick-end labeling—stained cells was performed. Whereas the amount of radiation-induced apoptosis in uninfected and dl312-infected control cells was relatively small (2.1 ± 0.05% and 3.7 ± 0.5%, respectively), the combination of Ad5CMV-p53 infection and radiation treatment significantly increased the apoptotic frequency (18.6 ± 1.4%). To determine whether infection with Ad5CMV-p53 resulted in increased expression of functional exogenous p53 protein, Western blot analysis of p53 was performed on U87MG cells that were exposed to 9 Gy of radiation 2 days after exposure to Ad5CMV-p53, dl312, or DMEM. Infection with Ad5CMV-p53 alone increased p53 levels compared with DMEM- or dl312-treated cells. Irradiation of Ad5CMV-p53—infected cells resulted in a further increase in p53 that reached a maximum at 2 hours postirradiation. To determine whether exogenous p53 provided by Ad5CMV-p53 had transactivating activity, U87MG cells were treated as described earlier and p21 messenger RNA levels were determined. Infection of U87MG cells with Ad5CMV-p53 only resulted in an increase in p21 compared with DMEM- and dl312-treated cells. Irradiation of Ad5CMV-p53—infected cells resulted in an additional time-dependent increase in p21 expression. Conclusions. These data indicate that adenovirus-mediated delivery of p53 may enhance the radioresponse of brain tumor cells containing wild-type p53 and that this radiosensitization may involve converting from a clonogenic to the more sensitive apoptotic form of cell death. Although the mechanism underlying this enhanced apoptotic susceptibility is unknown, the Ad5CMV-p53—infected cells have a higher level of p53 protein, which increases further after irradiation, and this exogenous p53 is transcriptionally active. Thus, it is possible that the combination of Ad5CMV-p53 infection and radiation treatment increases p53 protein to a level that is sufficient to overcome at least partially the block in apoptosis existing in U87MG cells.

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Inhibitory Effect of MicroRNA-376b-Overexpressing Bone Marrow Mesenchymal Stem Cells (BMSCs) on Malignant Characteristics of Glioma Cells Through Targeting Forkhead Box Protein P2 (FOXP2)

Journal of Biomaterials and Tissue Engineering ◽

10.1166/jbt.2022.2999 ◽

2022 ◽

Vol 12 (5) ◽

pp. 971-977

Author(s):

Ruoyu Zhu ◽

Zhonglin Wang

Keyword(s):

Glioma Cell ◽

Potential Role ◽

Glioma Cells ◽

Inhibitory Effect ◽

Transwell Assay ◽

Cell Behaviors ◽

Forkhead Box ◽

Marrow Mesenchymal Stem Cells ◽

The Impact

This study investigated the impact of microRNA (miR)-376b derived from BMSCs on glioma progression. BMSCs were transfected with miR-376b mimic, miR-376b inhibitor or NC and then cocultured with glioma cells followed by measuring cell behaviors by MTT assay, Transwell assay and flow cytometry, FOXP2 and miR-376b expression by Western blot and RT-qPCR. After confirming the inhibitory and mimicking activity of transfection, we found that overexpression of miR-376b in BMSCs decreased glioma cell invasion, migration and proliferation but promoted cell apoptosis within 24 h and 48 h after transfection along with reduced number of cells in S-phase. Mechanically, miR-376b targeted miR-376b and up-regulation of miR-376b caused down-regulation of FOXP2 (p < 0.05). Overexpression of miR-376b in BMSCs decelerated glioma cell cycle and inhibitedmalignant behaviors of glioma cells by targeting FOXP2 expression. These evidence unveils the potential role of FOXP2 as a biomarker for the treatment of gliomas.

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Parallel activation of de novo lipogenesis and stearoyl-CoA desaturase activity after 3 d of high-carbohydrate feeding

American Journal of Clinical Nutrition ◽

10.1093/ajcn/87.4.817 ◽

2008 ◽

Vol 87 (4) ◽

pp. 817-823 ◽

Cited By ~ 139

Author(s):

Mary F-F Chong ◽

Leanne Hodson ◽

Alex S Bickerton ◽

Rachel Roberts ◽

Matt Neville ◽

...

Keyword(s):

Desaturase Activity ◽

De Novo ◽

De Novo Lipogenesis ◽

High Carbohydrate ◽

Carbohydrate Feeding ◽

Stearoyl Coa Desaturase ◽

Parallel Activation

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EXTH-27. MOLECULAR CHARACTERIZATION AND PRECLINICAL DEVELOPMENT OF NOVEL SMALL MOLECULE INHIBITOR SPECIFIC FOR WILD-TYPE IDH1 FOR FERROPTOSIS INDUCTION IN GLIOBLASTOMA

Neuro-Oncology ◽

10.1093/neuonc/noab196.666 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi169-vi169

Author(s):

Kevin Murnan ◽

Serena Tommasini-Ghelfi ◽

Lisa Hurley ◽

Corey Dussold ◽

Daniel Wahl ◽

...

Keyword(s):

Fatty Acids ◽

Cell Death ◽

Plasma Membrane ◽

Fatty Acid ◽

Unsaturated Fatty Acids ◽

De Novo ◽

De Novo Lipogenesis ◽

Therapeutic Modality ◽

Wild Type ◽

Genetic Ablation

Abstract Increased de novo synthesis, mobilization and uptake of fatty acids are required to provide sufficient lipids for membrane biogenesis in support of rapid tumor cell division and growth. In addition to their structural roles as components of the plasma membrane, fatty acid-derived lipids regulate ferroptotic cell death, a type of programmed cell death, when oxidized by iron-dependent lipoxygenase enzymes. De novo lipogenesis and the defense against oxidative lipid damage require large amounts of cytosolic NADPH. Our group has recently found that HGG up-regulate wild-type Isocitrate dehydrogenase 1 (referred to hereafter as ‘wt-IDH1high HGG’) to generate large quantities of cytosolic NADPH. RNAi-mediated knockdown of wt-IDH1, alone and in combination with radiation therapy (RT), slows the growth of patient-derived HGG xenografts, while overexpression of wt-IDH1 promotes intracranial HGG growth. Isotope tracer and liquid chromatography-based lipidomic studies indicated that wt-IDH1 supports the de novo biosynthesis of mono-unsaturated fatty acids (MUFAs) and promotes the incorporation of monounsaturated phospholipids into the plasma membrane, while displacing polyunsaturated fatty acid (PUFA) phospholipids. In addition, enhanced NADPH production in wt-IDH1high HGG increases glutathione (GSH) level, reduces reactive oxygen species (ROS), activates the phospholipid peroxidase glutathione peroxidase 4 (GPX4)-driven lipid repair pathway, and dampens the accumulation of PUFA-containing lipid peroxides, known executioners of ferroptosis. To pharmacologically target wt-IDH1,we have used and characterized wt-IDH1i-13, a first-in-class competitive α,β-unsaturated enone (AbbVie). wt-IDH1i-13 potently inhibits wt-IDH1 enzymatic activity, by covalently binding to the NADP+ binding pocket. Our data indicate that wt-IDH1i-13 promotes ferroptosis, which can be rescued by pre-treatment of cells with the peroxyl scavenger and ferroptosis inhibitor ferrostatin. wt-IDH1i-13 is brain-penetrant, and similar to genetic ablation, reduces progression and extends the survival of wt-IDH1high HGG bearing mice, alone and in combination with RT. These studies credential to wt-IDH1i-13 as a novel therapeutic modality for the treatment of wt-IDH1 gliomas.

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Role of human liver lipogenesis and reesterification in triglycerides secretion and in FFA reesterification

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1998.274.2.e321 ◽

1998 ◽

Vol 274 (2) ◽

pp. E321-E327 ◽

Cited By ~ 13

Author(s):

Frederique Diraison ◽

Michel Beylot

Keyword(s):

Turnover Rate ◽

De Novo ◽

Plasma Free Fatty Acid ◽

Normal Subjects ◽

De Novo Lipogenesis ◽

Deuterated Water ◽

Extrahepatic Tissues ◽

Almost All ◽

State 1

To measure 1) the contribution of hepatic de novo lipogenesis (DNL) and plasma free fatty acid (FFA) reesterification to plasma triglyceride (TG) secretion, and 2) the role of oxidation and hepatic and extrahepatic reesterification in FFA utilization, five normal subjects drank deuterated water and were infused (postabsorptive state) with [1-13C]palmitate and [1,2,3-2H5]glycerol. Total lipid oxidation (Lox) was measured by indirect calorimetry. FFA oxidation (2.76 ± 0.65 μmol ⋅ kg−1 ⋅ min−1) accounted for 45% of FFA turnover rate (Rt) (1.04 μmol ⋅ kg−1 ⋅ min−1) and 91% of Lox; FFA reesterification was 3.27 ± 0.54 μmol ⋅ kg−1 ⋅ min−1. Fractional and absolute TG Rt were 0.21 ± 0.02 h−1 and 0.11 ± 0.05 μmol ⋅ kg−1 ⋅ min−1. DNL accounted for 3.9 ± 0.9% of TG secretion, and hepatic FFA reesterification accounted for 49.4 ± 5.7%; this last process represented a utilization of FFA of 0.16 ± 0.02 μmol ⋅ kg−1 ⋅ min−1. We conclude that, in the postabsorptive state, 1) DNL and FFA reesterification account for only 50–55% of TG secretion, the remaining presumably being provided by stored lipids or lipoproteins taken up by liver, 2) most reesterification occurs in extrahepatic tissues, and 3) oxidation and reesterification each contribute about one-half to FFA utilization; FFA oxidation accounts for almost all Lox.

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Loss of regulation of lipogenesis in the Zucker diabetic (ZDF) rat

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.2000.279.2.e425 ◽

2000 ◽

Vol 279 (2) ◽

pp. E425-E432 ◽

Cited By ~ 33

Author(s):

W.-N. Paul Lee ◽

Sara Bassilian ◽

Shu Lim ◽

Laszlo G. Boros

Keyword(s):

High Fat Diet ◽

Leptin Receptor ◽

De Novo ◽

De Novo Lipogenesis ◽

Chain Elongation ◽

Deuterated Water ◽

High Fat ◽

Macronutrient Composition ◽

Zdf Rat

We present here a study on the role of leptin in the regulation of lipogenesis by examining the effect of dietary macronutrient composition on lipogenesis in the leptin receptor-defective Zucker diabetic fatty rat (ZDF) and its lean litter mate (ZL). Animals were pair fed two isocaloric diets differing in their fat-to-carbohydrate ratio providing 10 and 30% energy as fat. Lipogenesis was measured in the rats using deuterated water and isotopomer analysis. From the deuterium incorporation into plasma palmitate, stearate, and oleate, we determined de novo synthesis of palmitate and synthesis of stearate by chain elongation and of oleate by desaturation. Because the macronutrient composition and the caloric density were controlled, changes in de novo lipogenesis under these dietary conditions represent adaptation to changes in the fat-to-carbohydrate ratio of the diet. De novo lipogenesis was normally suppressed in response to the high-fat diet in the ZL rat to maintain a relatively constant amount of lipids transported. The ZDF rat had a higher rate of lipogenesis, which was not suppressed by the high-fat diet. The results suggest an important hormonal role of leptin in the feedback regulation of lipogenesis.

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