Both insulin and epidermal growth factor stimulate fatty acid synthesis and increase phosphorylation of acetyl-CoA carboxylase and ATP-citrate lyase in isolated hepatocytes

The zonal distribution within rat liver of acetyl-CoA carboxylase, ATP citrate-lyase and fatty acid synthase, the principal enzymes of fatty acid synthesis, was investigated by using dual-digitonin-pulse perfusion. Analysis of enzyme mass by immunoblotting revealed that, in normally feeding male rats, the periportal/perivenous ratio of acetyl-CoA carboxylase mass was 1.9. The periportal/perivenous ratio of ATP citrate-lyase mass was 1.4, and fatty acid synthase exhibited the largest periportal/perivenous mass gradient, having a ratio of 3.1. This pattern of enzyme distribution was observed in male rats only; in females, the periportal/perivenous ratio of enzyme mass was nearly equal. The periportal/perivenous gradients for acetyl-CoA carboxylase, ATP citrate-lyase and fatty acid synthase observed in fed (and fasted) males were abolished when animals were fasted (48 h) and refed (30 h) with a high-carbohydrate/low-fat diet. As determined by enzyme assay of eluates obtained from the livers of normally feeding male rats, there is also periportal zonation of acetyl-CoA carboxylase activity, expressed either as units per mg of eluted protein or units per mg of acetyl-CoA carboxylase protein, suggesting the existence of gradients in both enzyme mass and specific activity. From these results, we conclude that the enzymes of fatty acid synthesis are zonated periportally in the liver of the normally feeding male rat.

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The role of phosphorylation in the regulation of fatty acid synthesis by insulin and other hormones

Philosophical Transactions of the Royal Society of London Series B Biological Sciences ◽

10.1098/rstb.1983.0036 ◽

1983 ◽

Vol 302 (1108) ◽

pp. 33-45 ◽

Cited By ~ 13

Keyword(s):

Fatty Acid ◽

Fatty Acid Synthesis ◽

Pyruvate Dehydrogenase ◽

Kinase Activity ◽

Acid Synthesis ◽

Fat Cells ◽

Acetyl Coa Carboxylase ◽

Atp Citrate Lyase ◽

Acetyl Coa ◽

Citrate Lyase

Insulin stimulates fatty acid synthesis in white and brown fat cells as well as in liver and mammary tissue. Hormones that increase cellular cyclic AMP concentrations inhibit fatty acid synthesis, at least in white adipose tissue and liver. These changes in fatty acid synthesis occur within minutes. In white fat cells, they are brought about not only by changes in glucose transport but also changes in the activities of pyruvate kinase, pyruvate dehydrogenase and acetyl-CoA carboxylase. The basis of the alterations in pyruvate kinase activity in fat cells is not understood. Unlike the liver isoenzyme, the isoenzyme present in fat cells does not appear to be phosphorylated either in the absence or presence of hormones. The changes in pyruvate dehydrogenase activity in fat cells are undoubtedly due to changes in phosphorylation of the α subunits. Insulin appears to act by causing the parallel dephosphorylation of all three sites. The persistence of the effect of insulin during the preparation and subsequent incubation of mitochondria has allowed the demonstration that insulin acts mainly by stimulating pyruvate dehydrogenase phosphatase rather than inhibiting the kinase. Acetyl-CoA carboxylase within fat cells is phosphorylated on a number of different sites. The exposure of cells to insulin leads to activation of the enzyme and this is associated with increased phosphorylation of a specific site on the enzyme. Exposure to adrenalin, which results in a marked diminution in activity, also causes a small increase in the overall level of phosphorylation, but this increase is due to an enhanced phosphorylation of different sites; probably those phosphorylated by cyclic-AMP-dependent protein kinase. Acetyl-CoA carboxylase is one of a number of proteins in fat cells that exhibit increased phosphorylation with insulin. Others include ATP-citrate lyase, the ribosomal protein S 6 , the β subunit of the insulin receptor and a heat and acid stable protein of M r 22 000. Changes in phosphorylation of ATP-citrate lyase do not appear to result in any appreciable changes in catalytic activity. A central aspect of insulin action may be the activation and perhaps release of a membrane-associated protein kinase. Plasma membranes from fat cells have been shown to contain a cyclicnucleotide-independent kinase able to phosphorylate and activate acetyl-CoA carboxylase. Furthermore, high-speed supernatant fractions from cells previously exposed to insulin contain elevated levels of the same or similar kinase activity capable of phosphorylating both ATP-citrate lyase and acetyl-CoA carboxylase.

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TAMI-05. FATTY ACID SYNTHESIS IS REQUIRED FOR HER2+ BREAST CANCER BRAIN METASTASIS

Neuro-Oncology ◽

10.1093/neuonc/noab196.789 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi199-vi199

Author(s):

Gino Ferraro ◽

Ahmed Ali ◽

Alba Luengo ◽

Amy Deik ◽

Keene Abbott ◽

...

Keyword(s):

Breast Cancer ◽

Epidermal Growth Factor Receptor ◽

Fatty Acid ◽

Growth Factor ◽

Fatty Acid Synthesis ◽

Growth Factor Receptor ◽

Breast Tumors ◽

Acid Synthesis ◽

Epidermal Growth ◽

The Brain

Abstract Brain metastases are refractory to therapies that control systemic disease in patients with human epidermal growth factor receptor 2-positive breast cancer and the brain microenvironment contributes to this therapy resistance. Nutrient availability can vary across tissues, therefore metabolic adaptations required for brain metastatic breast cancer growth may introduce liabilities that can be exploited for therapy. Here we assessed how metabolism differs between breast tumors in brain versus extracranial sites and found that fatty acid synthesis is elevated in breast tumors growing in the brain. We determine that this phenotype is an adaptation to decreased lipid availability in the brain relative to other tissues, resulting in site-specific dependency on fatty acid synthesis for breast tumors growing at this site. Genetic or pharmacological inhibition of fatty acid synthase reduces human epidermal growth factor receptor 2-positive breast tumor growth in the brain, demonstrating that differences in nutrient availability across metastatic sites can result in targetable metabolic dependencies.

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RNA-seq reveals novel mechanistic targets of withaferin A in prostate cancer cells

Carcinogenesis ◽

10.1093/carcin/bgaa009 ◽

2020 ◽

Vol 41 (6) ◽

pp. 778-789 ◽

Cited By ~ 5

Author(s):

Su-Hyeong Kim ◽

Eun-Ryeong Hahm ◽

Krishna B Singh ◽

Sruti Shiva ◽

Jacob Stewart-Ornstein ◽

...

Keyword(s):

Prostate Cancer ◽

Fatty Acid ◽

Fatty Acid Synthase ◽

Acid Synthesis ◽

Acetyl Coa Carboxylase ◽

Rna Seq ◽

Atp Citrate Lyase ◽

Acetyl Coa ◽

Citrate Lyase

Abstract Withaferin A (WA) is a promising phytochemical exhibiting in vitro and in vivo anticancer activities against prostate and other cancers, but the mechanism of its action is not fully understood. In this study, we performed RNA-seq analysis using 22Rv1 human prostate cancer cell line to identify mechanistic targets of WA. Kyoto Encyclopedia of Genes and Genomes pathway analysis of the differentially expressed genes showed most significant enrichment of genes associated with metabolism. These results were validated using LNCaP and 22Rv1 human prostate cancer cells and Hi-Myc transgenic mice as models. The intracellular levels of acetyl-CoA, total free fatty acids and neutral lipids were decreased significantly following WA treatment in both cells, which was accompanied by downregulation of mRNA (confirmed by quantitative reverse transcription-polymerase chain reaction) and protein levels of key fatty acid synthesis enzymes, including ATP citrate lyase, acetyl-CoA carboxylase 1, fatty acid synthase and carnitine palmitoyltransferase 1A. Ectopic expression of c-Myc, but not constitutively active Akt, conferred a marked protection against WA-mediated suppression of acetyl-CoA carboxylase 1 and fatty acid synthase protein expression, and clonogenic cell survival. WA was a superior inhibitor of cell proliferation and fatty acid synthesis in comparison with known modulators of fatty acid metabolism including cerulenin and etomoxir. Intraperitoneal WA administration to Hi-Myc transgenic mice (0.1 mg/mouse, three times/week for 5 weeks) also resulted in a significant decrease in circulating levels of total free fatty acids and phospholipids, and expression of ATP citrate lyase, acetyl-CoA carboxylase 1, fatty acid synthase and carnitine palmitoyltransferase 1A proteins in the prostate in vivo.

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Wnt10b Participates in Regulating Fatty Acid Synthesis in the Muscle of Zebrafish

Cells ◽

10.3390/cells8091011 ◽

2019 ◽

Vol 8 (9) ◽

pp. 1011

Author(s):

Dongwu Liu ◽

Qiuxiang Pang ◽

Qiang Han ◽

Qilong Shi ◽

Qin Zhang ◽

...

Keyword(s):

Fatty Acid ◽

Fatty Acid Synthesis ◽

Glycogen Synthase ◽

Fatty Acid Synthetase ◽

Acid Synthesis ◽

Atp Citrate Lyase ◽

Enhancer Binding Protein ◽

Citrate Lyase ◽

Gsk 3Β

There are 19 Wnt genes in mammals that belong to 12 subfamilies. Wnt signaling pathways participate in regulating numerous homeostatic and developmental processes in animals. However, the function of Wnt10b in fatty acid synthesis remains unclear in fish species. In the present study, we uncovered the role of the Wnt10b signaling pathway in the regulation of fatty acid synthesis in the muscle of zebrafish. The gene of Wnt10b was overexpressed in the muscle of zebrafish using pEGFP-N1-Wnt10b vector injection, which significantly decreased the expression of glycogen synthase kinase 3β (GSK-3β), but increased the expression of β-catenin, peroxisome proliferators-activated receptor γ (PPARγ), and CCAAT/enhancer binding protein α (C/EBPα). Moreover, the activity and mRNA expression of key lipogenic enzymes ATP-citrate lyase (ACL), acetyl-CoA carboxylase (ACC) and fatty acid synthetase (FAS), and the content of non-esterified fatty acids (NEFA), total cholesterol (TC), and triglyceride (TG) were also significantly decreased. Furthermore, interference of the Wnt10b gene significantly inhibited the expression of β-catenin, PPARγ, and C/EBPα, but significantly induced the expression of GSK-3β, FAS, ACC, and ACL. The content of NEFA, TC, and TG as well as the activity of FAS, ACC, and ACL significantly increased. Thus, our results showed that Wnt10b participates in regulating fatty acid synthesis via β-catenin, C/EBPα and PPARγ in the muscle of zebrafish.

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Metabolic adaptations during lactogenesis. Fatty acid synthesis in rabbit mammary tissue during pregnancy and lactation

Biochemical Journal ◽

10.1042/bj1380373 ◽

1974 ◽

Vol 138 (3) ◽

pp. 373-379 ◽

Cited By ~ 36

Author(s):

R. W. Mellenberger ◽

D. E. Bauman

Keyword(s):

Fatty Acid ◽

Fatty Acid Synthesis ◽

Acid Synthesis ◽

Co2 Production ◽

Mammary Tissue ◽

Atp Citrate Lyase ◽

Acetyl Coa ◽

Citrate Lyase ◽

Pregnancy And Lactation ◽

Synthetic Capacity

1. Mammary tissue was obtained from rabbits at various stages of pregnancy and lactation and used for tissue-slice incubations (to measure the rate of fatty acid synthesis and CO2 production) and to determine relevant enzymic activities. A biphasic adaptation in fatty acid synthetic capacity during lactogenesis was noted. 2. The first lactogenic response occurred between day 15 and 24 of pregnancy. Over this period fatty acid synthesis (from acetate) increased 14-fold and the proportions of fatty acids synthesized changed to those characteristic of milk fat (77–86% as C8:0+C10:0 acids). 3. The second lactogenic response occurred post partum as indicated by increased rates of fatty acid synthesis and CO2 production (from acetate and glucose) and increased enzymic activities. 4. Major increases in enzymic activities between mid-pregnancy and lactation were noted for ATP citrate lyase (EC 4.1.3.8), acetyl-CoA synthetase (EC 6.2.1.1), acetyl-CoA carboxylase (EC 6.4.1.2), fatty acid synthetase, glucose 6-phosphate dehydrogenase (EC 1.1.1.49), and 6-phosphogluconate dehydrogenase (EC 1.1.1.44). Smaller increases in activity occurred with glycerol 3-phosphate dehydrogenase (EC 1.1.1.8) and NADP+–isocitrate dehydrogenase (EC 1.1.1.42) and the activity of NADP+–malate dehydrogenase (EC 1.1.1.40) was negligible at all periods tested. 5. During pregnancy and lactation there was a close temporal relationship between fatty acid synthetic capacity and the activities of ATP citrate lyase (r=0.94) and acetyl-CoA carboxylase (r=0.90).

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