scholarly journals The Spot 14 Protein Is Required for de Novo Lipid Synthesis in the Lactating Mammary Gland

Endocrinology ◽  
2005 ◽  
Vol 146 (8) ◽  
pp. 3343-3350 ◽  
Author(s):  
Qihong Zhu ◽  
Grant W. Anderson ◽  
Gregory T. Mucha ◽  
Elizabeth J. Parks ◽  
Jennifer K. Metkowski ◽  
...  
Keyword(s):  
Mammary Gland ◽  
De Novo ◽  
Lipid Synthesis ◽  
De Novo Lipogenesis ◽  
Direct Result ◽  
Maximum Efficiency ◽  
Null Mouse ◽  
Wild Type ◽  
Spot 14 ◽  
Lactating Mammary Gland

Abstract We generated a Spot 14 null mouse to assess the role of Spot 14 in de novo lipid synthesis and report the Spot 14 null mouse exhibits a phenotype in the lactating mammary gland. Spot 14 null pups nursed by Spot 14 null dams gain significantly less weight than wild-type pups nursed by wild-type dams. In contrast, Spot 14 null pups nursed by heterozygous dams show similar weight gain to wild-type littermates. We found the triglyceride content in Spot 14 null milk is significantly reduced. We demonstrate this reduction is the direct result of decreased de novo lipid synthesis in lactating mammary glands, corroborated by a marked reduction of medium-chain fatty acids in the triglyceride pool. Importantly, the reduced lipogenic rate is not associated with significant changes in the activities or mRNA of key lipogenic enzymes. Finally, we report the expression of a Spot 14-related gene in liver and adipose tissue, which is absent in the lactating mammary gland. We suggest that expression of both the Spot 14 and Spot 14-related proteins is required for maximum efficiency of de novo lipid synthesis in vivo and that these proteins impart a novel mechanism regulating de novo lipogenesis.

scholarly journals Overlapping Roles of the Glucose-Responsive Genes, S14 and S14R, in Hepatic Lipogenesis

Endocrinology ◽  
2010 ◽  
Vol 151 (5) ◽  
pp. 2071-2077 ◽  
Author(s):  
Derrick L. Aipoalani ◽  
Brennon L. O'Callaghan ◽  
Douglas G. Mashek ◽  
Cary N. Mariash ◽  
Howard C. Towle
Keyword(s):  
De Novo ◽  
Dietary Factors ◽  
De Novo Lipogenesis ◽  
Mammary Tissue ◽  
Null Mouse ◽  
Lipogenic Enzyme ◽  
Hepatic Lipogenesis ◽  
Hepatic Expression ◽  
Lactating Mammary Gland ◽  
Interfering Rna

The Spot 14 (S14; Thrsp) gene has been implicated in supporting regulated lipogenesis in mammals. S14 gene expression in liver is controlled by a wide variety of hormones and dietary factors in parallel with the major lipogenic enzyme genes. In addition, mice deleted for the S14 gene display reduced de novo lipogenesis in the lactating mammary gland. However, no decrease in hepatic lipogenesis was observed in the S14 null mouse. It was postulated that this difference could be due to the expression of a paralogous gene called S14R (S14 related; Mig12) in the liver but not mammary tissue. To test this hypothesis, we used small interfering RNA to simultaneously reduce levels of S14 and S14R in cultured primary hepatocytes. We found that rates of lipogenesis were decreased by approximately 65% in cells treated with insulin and high glucose. This reduction was associated with a decrease in total liver triacylglycerols and an altered morphology of lipid droplets. Expression of either S14 or S14R gene products was sufficient to fully restore normal lipogenesis. No change in the hepatic expression of other major lipogenic enzyme genes occurred during manipulation of S14 and/or S14R levels. These data support the hypothesis that both S14 and S14R are directly involved in supporting hepatic lipogenesis and that the two proteins play overlapping roles in this process.

scholarly journals Snf1 Is a Regulator of Lipid Accumulation in Yarrowia lipolytica

2013 ◽  
Vol 79 (23) ◽  
pp. 7360-7370 ◽  
Author(s):  
John Seip ◽  
Raymond Jackson ◽  
Hongxian He ◽  
Quinn Zhu ◽  
Seung-Pyo Hong
Keyword(s):  
Yarrowia Lipolytica ◽  
Lipid Accumulation ◽  
Oleaginous Yeast ◽  
De Novo ◽  
Lipid Synthesis ◽  
Omega 3 ◽  
Wild Type ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Dry Cell Weight

ABSTRACTIn the oleaginous yeastYarrowia lipolytica,de novolipid synthesis and accumulation are induced under conditions of nitrogen limitation (or a high carbon-to-nitrogen ratio). The regulatory pathway responsible for this induction has not been identified. Here we report that the SNF1 pathway plays a key role in the transition from the growth phase to the oleaginous phase inY. lipolytica. Strains with aY. lipolyticasnf1(Ylsnf1) deletion accumulated fatty acids constitutively at levels up to 2.6-fold higher than those of the wild type. When introduced into aY. lipolyticastrain engineered to produce omega-3 eicosapentaenoic acid (EPA),Ylsnf1deletion led to a 52% increase in EPA titers (7.6% of dry cell weight) over the control. Other components of theY. lipolyticaSNF1 pathway were also identified, and their function in limiting fatty acid accumulation is suggested by gene deletion analyses. Deletion of the gene encoding YlSnf4, YlGal83, or YlSak1 significantly increased lipid accumulation in both growth and oleaginous phases compared to the wild type. Furthermore, microarray and quantitative reverse transcription-PCR (qRT-PCR) analyses of theYlsnf1mutant identified significantly differentially expressed genes duringde novolipid synthesis and accumulation inY. lipolytica. Gene ontology analysis found that these genes were highly enriched with genes involved in lipid metabolism. This work presents a new role for Snf1/AMP-activated protein kinase (AMPK) pathways in lipid accumulation in this oleaginous yeast.

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

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi206-vi206
Author(s):  
Tomohiro Yamasaki ◽  
Lumin Zhang ◽  
Tyrone Dowdy ◽  
Adrian Lita ◽  
Mark Gilbert ◽  
...  
Keyword(s):  
Glioma Cell ◽  
De Novo ◽  
Glioma Cells ◽  
Model Systems ◽  
De Novo Lipogenesis ◽  
Wild Type ◽  
Knock Out ◽  
Stearoyl Coa Desaturase ◽  
Scd1 Expression

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.

scholarly journals Spot 14: A Marker of Aggressive Breast Cancer and a Potential Therapeutic Target

Endocrinology ◽  
2006 ◽  
Vol 147 (9) ◽  
pp. 4048-4055 ◽  
Author(s):  
William B. Kinlaw ◽  
Jennifer L. Quinn ◽  
Wendy A. Wells ◽  
Christopher Roser-Jones ◽  
Joel T. Moncur
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Therapeutic Target ◽  
Milk Fat ◽  
Breast Cancer Cells ◽  
De Novo ◽  
Lipid Synthesis ◽  
Breast Cancers ◽  
Spot 14 ◽  
Aggressive Breast Cancer

Spot 14 (S14) is a nuclear protein that communicates the status of dietary fuels and fuel-related hormones to genes required for long-chain fatty acid synthesis. In mammary gland, S14 is important for both epithelial proliferation and milk fat production. The S14 gene is amplified in some breast cancers and is strongly expressed in most. High expression of S14 in primary invasive breast cancer is conspicuously predictive of recurrence. S14 mediates the induction of lipogenesis by progestin in breast cancer cells and accelerates their growth. Conversely, S14 knockdown impairs de novo lipid synthesis and causes apoptosis. We found that breast cancer cells do not express lipoprotein lipase (LPL) and hypothesize that they do not have access to circulating lipids unless the local environment supplies it. This may explain why primary breast cancers with low S14 do not survive transit from the LPL-rich mammary fat pad to areas devoid of LPL, such as lymph nodes, and thus do not appear as distant metastases. Thus, S14 is a marker for aggressive breast cancer and a potential target as well. Future effort will center on validation of S14 as a therapeutic target and producing antagonists of its action.

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

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.

scholarly journals Quantifying carbon sources for de novo lipogenesis in wild-type and IRS-1 knockout brown adipocytes

2004 ◽  
Vol 45 (7) ◽  
pp. 1324-1332 ◽  
Author(s):  
Hyuntae Yoo ◽  
Gregory Stephanopoulos ◽  
Joanne K. Kelleher
Keyword(s):  
De Novo ◽  
Carbon Sources ◽  
De Novo Lipogenesis ◽  
Wild Type ◽  
Brown Adipocytes

Expression and nutritional regulation of lipogenic genes in mammary gland and adipose tissues of lactating goats

2005 ◽  
Vol 72 (2) ◽  
pp. 250-255 ◽  
Author(s):  
Laurence Bernard ◽  
Christine Leroux ◽  
Muriel Bonnet ◽  
Jacques Rouel ◽  
Patrice Martin ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Milk Fat ◽  
De Novo ◽  
Lipid Synthesis ◽  
Nutritional Regulation ◽  
Lipogenic Genes ◽  
Lactating Goats ◽  
Negative Effect ◽  
Few Data ◽  
Long Chain

While the effect of long-chain fatty acids on adipose tissue (AT) lipogenic activities has been described in non-lactating ruminants (Vernon, 1977), little is known about their effects on the mammary gland and the AT in lactating animals. However, in cows in mid lactation, duodenal rapeseed oil infusion decreased the rate of fatty acid (FA) synthesis in AT and increased milk yield of long-chain FA (18[ratio ]1, 18[ratio ]2 and 18[ratio ]3) and decreased medium-chain FA (14[ratio ]0 and 16[ratio ]0), suggesting a depressive effect of fat feeding on mammary lipid synthesis de novo (Chilliard et al. 1991). On the other hand, in goat species, the addition of vegetable lipids to the diet led to an increase in the milk fat content and yield (Chilliard et al. 2003) suggesting that the possible negative effect of long-chain FA on FA synthesis in the lactating mammary gland could be more than compensated by increasing the supply of FA brought to the mammary gland for milk synthesis. Elsewhere, AT from various anatomical sites are characterized by different FA composition in goat (Bas et al. 1987) together with different patterns of lipogenic gene expression in sheep (Barber et al. 2000). These results suggest that each AT site is characterized by a specific metabolism. However, in lactating ruminants, few data are available on the extent of expression and regulation of genes coding for lipogenic enzymes in AT. Therefore, the current study was performed in three lipogenic tissues of lactating goats, namely the mammary gland, an internal AT site (perirenal AT) and an external AT site (subcutaneous AT).

scholarly journals Sterol regulatory element binding protein and dietary lipid regulation of fatty acid synthesis in the mammary epithelium

2010 ◽  
Vol 299 (6) ◽  
pp. E918-E927 ◽  
Author(s):  
Michael C. Rudolph ◽  
Jenifer Monks ◽  
Valerie Burns ◽  
Meridee Phistry ◽  
Russell Marians ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Regulatory Element ◽  
Acid Synthesis ◽  
De Novo Lipogenesis ◽  
Mrna Levels ◽  
Sterol Regulatory Element

The lactating mammary gland synthesizes large amounts of triglyceride from fatty acids derived from the blood and from de novo lipogenesis. The latter is significantly increased at parturition and decreased when additional dietary fatty acids become available. To begin to understand the molecular regulation of de novo lipogenesis, we tested the hypothesis that the transcription factor sterol regulatory element binding factor (SREBF)-1c is a primary regulator of this system. Expression of Srebf1c mRNA and six of its known target genes increased ≥2.5-fold at parturition. However, Srebf1c-null mice showed only minor deficiencies in lipid synthesis during lactation, possibly due to compensation by Srebf1a expression. To abrogate the function of both isoforms of Srebf1, we bred mice to obtain a mammary epithelial cell-specific deletion of SREBF cleavage-activating protein (SCAP), the SREBF escort protein. These dams showed a significant lactation deficiency, and expression of mRNA for fatty acid synthase ( Fasn), insulin-induced gene 1 ( Insig1), mitochondrial citrate transporter ( Slc25a1), and stearoyl-CoA desaturase 2 ( Scd2) was reduced threefold or more; however, the mRNA levels of acetyl-CoA carboxylase-1α ( Acaca) and ATP citrate lyase ( Acly) were unchanged. Furthermore, a 46% fat diet significantly decreased de novo fatty acid synthesis and reduced the protein levels of ACACA, ACLY, and FASN significantly, with no change in their mRNA levels. These data lead us to conclude that two modes of regulation exist to control fatty acid synthesis in the mammary gland of the lactating mouse: the well-known SREBF1 system and a novel mechanism that acts at the posttranscriptional level in the presence of SCAP deletion and high-fat feeding to alter enzyme protein.

Androgen stimulates glycolysis for de novo lipid synthesis by increasing the activities of hexokinase 2 and 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 2 in prostate cancer cells

2010 ◽  
Vol 433 (1) ◽  
pp. 225-233 ◽  
Author(s):  
Jong-Seok Moon ◽  
Won-Ji Jin ◽  
Jin-Hye Kwak ◽  
Hyo-Jeong Kim ◽  
Mi-Jin Yun ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Transcriptional Activation ◽  
De Novo ◽  
Lipid Synthesis ◽  
Signalling Pathway ◽  
De Novo Lipogenesis ◽  
Lncap Cells ◽  
Prostate Cancer Cells ◽  
Hexokinase 2

Up-regulation of lipogenesis by androgen is one of the most characteristic metabolic features of LNCaP prostate cancer cells. The present study revealed that androgen increases glucose utilization for de novo lipogenesis in LNCaP cells through the activation of HK2 (hexokinase 2) and activation of the cardiac isoform of PFKFB2 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase). Activation of PKA (cAMP-dependent protein kinase) by androgen increased phosphorylation of CREB [CRE (cAMP-response element)-binding protein], which in turn bound to CRE on the promoter of the HK2 gene resulting in transcriptional activation of the HK2 gene. Up-regulation of PFKFB2 expression was mediated by the direct binding of ligand-activated androgen receptor to the PFKFB2 promoter. The activated PI3K (phosphoinositide 3-kinase)/Akt signalling pathway in LNCaP cells contributes to the phosphorylation of PFKFB2 at Ser466 and Ser483, resulting in the constitutive activation of PFK-2 (6-phosphofructo-2-kinase) activity. Glucose uptake and lipogenesis were severely blocked by knocking-down of PFKFB2 using siRNA (small interfering RNA) or by inhibition of PFK-2 activity with LY294002 treatment. Taken together, our results suggest that the induction of de novo lipid synthesis by androgen requires the transcriptional up-regulation of HK2 and PFKFB2, and phosphorylation of PFKFB2 generated by the PI3K/Akt signalling pathway to supply the source for lipogenesis from glucose in prostate cancer cells.

scholarly journals The DAXX-SREBP axis promotes oncogenic lipogenesis and tumorigenesis

2021 ◽  
Author(s):  
Iqbal Mahmud ◽  
Guimei Tian ◽  
Jia Wang ◽  
Jessica Lewis ◽  
Aaron Waddell ◽  
...  
Keyword(s):  
Gene Expression ◽  
Tumor Growth ◽  
De Novo ◽  
Lipid Synthesis ◽  
De Novo Lipogenesis ◽  
Recent Analysis ◽  
Gene Promoters ◽  
Lipogenic Gene ◽  
Lipogenic Gene Expression ◽  
Cancer Types

ABSTRACTDe novo lipogenesis produces lipids for membrane biosynthesis and cell signaling. Elevated lipogenesis is a major metabolic feature in cancer cells. In breast and other cancer types, genes involved in lipogenesis are highly upregulated, but the mechanisms that control their expression remain poorly understood. DAXX modulates gene expression through binding to diverse transcription factors although the functional impact of these diverse interactions remains to be defined. Our recent analysis indicates that DAXX is overexpressed in diverse cancer types. However, mechanisms underlying DAXX’s oncogenic function remains elusive. Using global integrated transcriptomic and lipidomic analyses, we show that DAXX plays a key role in lipid metabolism. DAXX depletion attenuates, while its overexpression enhances, lipogenic gene expression, lipid synthesis and tumor growth. Mechanistically, DAXX interacts with SREBP1 and SREBP2 and activates SREBP-mediated transcription. DAXX associates with lipogenic gene promoters through SREBPs. Underscoring the critical roles for the DAXX-SREBP interaction for lipogenesis, SREBP2 knockdown attenuates tumor growth in cells with DAXX overexpression, and a DAXX mutant unable to bind SREBPs are incapable of promoting lipogenesis and tumor growth. Our results identify the DAXX-SREBP axis as an important pathway for tumorigenesis.

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