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Synthesis and engineering of mesoporous ZnO@HAP heterostructure as a pH-sensitive nano-photosensitizer for chemo-photodynamic therapy of malignant tumor cells. J Drug Deliv Sci Technol 2019. [DOI: 10.1016/j.jddst.2019.101200] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Alavi AS, Meshkini A. Fabrication of poly(ethylene glycol)-coated mesoporous nanocomposite ZnO@Fe2O3 for methotrexate delivery: An integrated nanoplatform for dual-mode cancer therapy. Eur J Pharm Sci 2018; 115:144-157. [DOI: 10.1016/j.ejps.2018.01.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 12/22/2017] [Accepted: 01/11/2018] [Indexed: 12/16/2022]
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Maldonado LY, Arsene D, Mato JM, Lu SC. Methionine adenosyltransferases in cancers: Mechanisms of dysregulation and implications for therapy. Exp Biol Med (Maywood) 2017; 243:107-117. [PMID: 29141455 DOI: 10.1177/1535370217740860] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Methionine adenosyltransferase genes encode enzymes responsible for the biosynthesis of S-adenosylmethionine, the principal biological methyl donor and precursor of polyamines and glutathione. Mammalian cells express three genes - MAT1A, MAT2A, and MAT2B - with distinct expression and functions. MAT1A is mainly expressed in the liver and maintains the differentiated states of both hepatocytes and bile duct epithelial cells. Conversely, MAT2A and MAT2B are widely distributed in non-parenchymal cells of the liver and extrahepatic tissues. Increasing evidence suggests that methionine adenosyltransferases play significant roles in the development of cancers. Liver cancers, namely hepatocellular carcinoma and cholangiocarcinoma, involve dysregulation of all three methionine adenosyltransferase genes. MAT1A reduction is associated with increased oxidative stress, progenitor cell expansion, genomic instability, and other mechanisms implicated in tumorigenesis. MAT2A/MAT2B induction confers growth and survival advantage to cancerous cells, enhancing tumor migration. Highlighted examples from colon, gastric, breast, pancreas and prostate cancer studies further underscore methionine adenosyltransferase genes' role beyond the liver in cancer development. In this subset of extra-hepatic cancers, MAT2A and MAT2B are induced via different regulatory mechanisms. Understanding the role of methionine adenosyltransferase genes in tumorigenesis helps identify attributes of these genes that may serve as valuable targets for therapy. While S-adenosylmethionine, and its metabolite, methylthioadenosine, have been largely explored as therapeutic interventions, targets aimed at regulation of MAT gene expression and methionine adenosyltransferase protein-protein interactions are now surfacing as potential effective strategies for treatment and chemoprevention of cancers. Impact statement This review examines the role of methionine adenosyltransferases (MATs) in human cancer development, with a particular focus on liver cancers in which all three MAT genes are implicated in tumorigenesis. An overview of MAT genes, isoenzymes and their regulation provide context for understanding consequences of dysregulation. Highlighting examples from liver, colon, gastric, breast, pancreas and prostate cancers underscore the importance of understanding MAT's tumorigenic role in identifying future targets for cancer therapy.
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Affiliation(s)
- Lauren Y Maldonado
- 1 Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Diana Arsene
- 2 Division of Gastroenterology and Hepatology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - José M Mato
- 3 CIC bioGUNE, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Technology, Derio, Bizkaia 48160, Spain
| | - Shelly C Lu
- 4 Division of Digestive and Liver Diseases, 22494 Cedars-Sinai Medical Center , Cedars-Sinai Medical Center, LA, CA 90048, USA
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Abstract
Methionine adenosyltransferases (MATs) are essential for cell survival because they catalyze the biosynthesis of the biological methyl donor S-adenosylmethionine (SAMe) from methionine and adenosine triphosphate (ATP). Mammalian cells express two genes, MAT1A and MAT2A, which encode two MAT catalytic subunits, α1 and α2, respectively. The α1 subunit organizes into dimers (MATIII) or tetramers (MATI). The α2 subunit is found in the MATII isoform. A third gene MAT2B, encodes a regulatory subunit β, that regulates the activity of MATII by lowering the inhibition constant (Ki) for SAMe and the Michaelis constant (Km) for methionine. MAT1A expressed mainly in hepatocytes maintains the differentiated state of these cells whereas MAT2A and MAT2B are expressed in non-parenchymal cells of the liver (hepatic stellate cells [HSCs] and Kupffer cells) and extrahepatic tissues. A switch from the liver-specific MAT1A to MAT2A has been observed during conditions of active liver growth and de-differentiation. Liver injury, fibrosis, and cancer are associated with MAT1A silencing and MAT2A/MAT2B induction. Even though both MAT1A and MAT2A are involved in SAMe biosynthesis, they exhibit distinct molecular interactions in liver cells. This review provides an update on MAT genes and their roles in liver pathologies.
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Affiliation(s)
- Komal Ramani
- Corresponding authors: Division of Digestive and Liver
Diseases, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA,
USA (K.Ramani)
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Kim SY, Hong SW, Kim MO, Kim HS, Jang JE, Leem J, Park IS, Lee KU, Koh EH. S-adenosyl methionine prevents endothelial dysfunction by inducing heme oxygenase-1 in vascular endothelial cells. Mol Cells 2013; 36:376-84. [PMID: 24046187 PMCID: PMC3887983 DOI: 10.1007/s10059-013-0210-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 08/09/2013] [Accepted: 08/12/2013] [Indexed: 01/12/2023] Open
Abstract
S-adenosyl methionine (SAM) is a key intermediate in the metabolism of sulfur amino acids and is a major methyl donor in the cell. Although the low plasma level of SAM has been associated with atherosclerosis, the effect of SAM administration on atherosclerosis is not known. Endothelial dysfunction is an early prerequisite for atherosclerosis. This study was undertaken to investigate the possible preventive effect of SAM on endothelial dysfunction and the molecular mechanism of its action. SAM treatment prevented endothelial dysfunction in high fat diet (HFD)-fed rats. In cultured human aortic endothelial cells, linoleic acid (LA) increased and SAM decreased cell apoptosis and endoplasmic reticulum stress. Both LA and SAM increased heme oxygenase-1 (HO-1) expression in an NF-E2-related factor 2-dependent manner. However, knockdown of HO-1 reversed only the SAM-induced preventive effect of cell apoptosis. The LA-induced HO-1 expression was dependent on PPARα, whereas SAM induced HO-1 in a PPAR-independent manner. These data demonstrate that SAM treatment prevents endothelial dysfunction in HFDfed animals by inducing HO-1 in vascular endothelial cells. In cultured endothelial cells, SAM-induced HO-1 was responsible for the observed prevention of cell apoptosis. We propose that SAM treatment may represent a new therapeutic strategy for atherosclerosis.
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Affiliation(s)
- Sun Young Kim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 138-736, Korea
| | - Seok Woo Hong
- Department of Anatomy, College of Medicine, Inha University, Incheon 401-103, Korea
| | - Mi-Ok Kim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 138-736, Korea
| | - Hyun-Sik Kim
- Asan Institute for Life Sciences, Asan Medical Center, Seoul 138-736, Korea
| | - Jung Eun Jang
- Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 138-736, Korea
| | - Jaechan Leem
- Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 138-736, Korea
| | - In-Sun Park
- Department of Anatomy, College of Medicine, Inha University, Incheon 401-103, Korea
| | - Ki-Up Lee
- Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 138-736, Korea
| | - Eun Hee Koh
- Department of Internal Medicine, University of Ulsan College of Medicine, Seoul 138-736, Korea
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Modulation of Liver l-γ-Glutamyl-l-cysteinylglycine Homeostasis By N-Acetyl-Glucosamine-thiazolidine-4(R)-carboxylic Acid in Mice. Am J Med Sci 2012; 343:310-5. [DOI: 10.1097/maj.0b013e31822b02f4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Wu D, Wang X, Zhou R, Cederbaum A. CYP2E1 enhances ethanol-induced lipid accumulation but impairs autophagy in HepG2 E47 cells. Biochem Biophys Res Commun 2010; 402:116-22. [PMID: 20932821 DOI: 10.1016/j.bbrc.2010.09.127] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 09/29/2010] [Indexed: 02/07/2023]
Abstract
The regulation and function of autophagy and lipid metabolism have recently been reported to be reciprocally related. Macroautophagy mediates the breakdown of lipids stored in lipid droplets. An inhibition of autophagy leads to the development of a fatty liver. We evaluated the ability of CYP2E1 to modulate the effects of ethanol on lipid accumulation and autophagy in vitro. The E47 HepG2 cell which expresses CYP2E1 was treated with ethanol at 50, 100 and 150mM for 4 or 5days. Ethanol-induced lipid accumulation and an increase of triglycerides (TG) in E47 cells to a greater extent than in control C34 cells which do not express CYP2E1. In contrast, autophagy (LC3 II/LC3 I ratio) was significantly induced by ethanol in C34 cells to a greater extent than in E47 cells. P62 was significantly increased in E47 cells after ethanol treatment. Thus, there is a reciprocal relationship between the effects of ethanol on lipid accumulation and autophagy in the CYP2E1-expressing cells. Inhibition of autophagy by 3-methyladenine (3MA), increased lipid accumulation and TG levels in C34 cells which display elevated autophagy, but enhanced lipid accumulation and TG level to a lesser extent in E47 cells which displayed lower autophagy. Ethanol induced CYP2E1 activity and oxidative stress in E47 cells compared with C34 cells. These experiments suggest that the expression of CYP2E1 may impair autophagy formation which contributes to lipid accumulation in the liver. We hypothesize that CYP2E1-induced oxidative stress promotes the accumulation of lipid droplets by ethanol and this may be responsible for the suppression of autophagy in the liver.
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Affiliation(s)
- Defeng Wu
- Department of Pharmacology & Systems Therapeutics, Mount Sinai School of Medicine, New York, NY 10029,USA
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Cederbaum AI. Hepatoprotective effects of S-adenosyl-L-methionine against alcohol- and cytochrome P450 2E1-induced liver injury. World J Gastroenterol 2010; 16:1366-76. [PMID: 20238404 PMCID: PMC2842529 DOI: 10.3748/wjg.v16.i11.1366] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
S-adenosyl-L-methionine (SAM) acts as a methyl donor for methylation reactions and participates in the synthesis of glutathione. SAM is also a key metabolite that regulates hepatocyte growth, differentiation and death. Hepatic SAM levels are decreased in animal models of alcohol liver injury and in patients with alcohol liver disease or viral cirrhosis. This review describes the protection by SAM against alcohol and cytochrome P450 2E1-dependent cytotoxicity both in vitro and in vivo and evaluates mechanisms for this protection.
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Bardag-Gorce F, Li J, Oliva J, Lu SC, French BA, French SW. The cyclic pattern of blood alcohol levels during continuous ethanol feeding in rats: the effect of feeding S-adenosylmethionine. Exp Mol Pathol 2010; 88:380-7. [PMID: 20303346 DOI: 10.1016/j.yexmp.2010.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Accepted: 03/08/2010] [Indexed: 12/19/2022]
Abstract
S-adenosylmethionine (SAMe), the major methyl donor for DNA and histone methylation was fed with ethanol for 1month in order to modify the effects of ethanol on rat liver. The following parameters were studied to determine the effects of SAMe; liver histology, the blood alcohol cycle (BAL), changes in gene expression mined from microarray analysis, changes in histone methylation, changes in liver SAMe levels and its metabolites and ADH. SAMe changed the type of fatty liver, reduced liver ALT levels and prevented the BAL cycle caused by intragastric ethanol feeding. Microarray analysis showed that SAMe feeding prevented most of the changes in gene expression induced by ethanol feeding, presumably by inducing H3K27me3 and gene silencing. H3K27me3 was significantly increased by SAMe with or without ethanol feeding. It is concluded that SAMe feeding stabilized global gene expression so that the changes in gene expression involved in the blood alcohol cycle were prevented.
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Affiliation(s)
- F Bardag-Gorce
- Department of Pathology, Harbor-UCLA Medical Center, Torrance, CA 90509, USA
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Cederbaum AI, Lu Y, Wu D. Role of oxidative stress in alcohol-induced liver injury. Arch Toxicol 2009; 83:519-48. [PMID: 19448996 DOI: 10.1007/s00204-009-0432-0] [Citation(s) in RCA: 429] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 04/28/2009] [Indexed: 02/06/2023]
Abstract
Reactive oxygen species (ROS) are highly reactive molecules that are naturally generated in small amounts during the body's metabolic reactions and can react with and damage complex cellular molecules such as lipids, proteins, or DNA. Acute and chronic ethanol treatments increase the production of ROS, lower cellular antioxidant levels, and enhance oxidative stress in many tissues, especially the liver. Ethanol-induced oxidative stress plays a major role in the mechanisms by which ethanol produces liver injury. Many pathways play a key role in how ethanol induces oxidative stress. This review summarizes some of the leading pathways and discusses the evidence for their contribution to alcohol-induced liver injury. Special emphasis is placed on CYP2E1, which is induced by alcohol and is reactive in metabolizing and activating many hepatotoxins, including ethanol, to reactive products, and in generating ROS.
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Affiliation(s)
- Arthur I Cederbaum
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, Box 1603, One Gustave L Levy Place, New York, NY 10029, USA.
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Wang X, Cederbaum AI. S-adenosyl-L-methionine decreases the elevated hepatotoxicity induced by Fas agonistic antibody plus acute ethanol pretreatment in mice. Arch Biochem Biophys 2008; 477:1-11. [PMID: 18482574 DOI: 10.1016/j.abb.2008.04.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 04/19/2008] [Accepted: 04/23/2008] [Indexed: 12/29/2022]
Abstract
The current study was designed to investigate the effect and potential mechanism of exogenous administration of S-adenosyl-l-methionine (SAM) on the enhanced hepatotoxicity induced by the Fas agonistic Jo2 antibody plus acute ethanol pretreatment in C57BL/6 mice. Acute ethanol plus Jo2 treatment produces liver toxicity under conditions in which ethanol alone or Jo2 alone do not. SAM significantly attenuated this elevated hepatotoxicity in mice as manifested by a decrease of serum aminotransferases and morphological amelioration. Levels of SAM and activity of methionine adenosyltransferase were lowered by the ethanol plus Jo2 treatment but restored by administration of SAM. The ethanol plus Jo2 treatment increased activity and content of CYP2E1, iNOS content and TNF-alpha levels; these increases were blunted by SAM. SAM also protected against the elevated oxidative and nitrosative stress found after ethanol plus Jo2, likely due to the decreases in CYP2E1, iNOS and TNF-alpha. Calcium-induced swelling of mitochondria was enhanced by the ethanol plus Jo2 treatment and this was prevented by SAM. JNK and P38 MAPK were activated by the ethanol plus Jo2 treatment; JNK activation was partially prevented by SAM. It is suggested that SAM protects against the ethanol plus Jo2 toxicity by restoring hepatic SAM levels, preventing the increase in iNOS, CYP2E1 and TNF-alpha and there by lowering the elevated oxidative/nitrosative stress and activation of the JNK signal pathway, ultimately preventing mitochondrial damage.
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Affiliation(s)
- Xiaodong Wang
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, One Gustave L. Levy Place, 1468 Madison Avenue, New York, NY 10029, USA.
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A decrease in S-adenosyl-L-methionine potentiates arachidonic acid cytotoxicity in primary rat hepatocytes enriched in CYP2E1. Mol Cell Biochem 2008; 314:105-12. [PMID: 18414994 DOI: 10.1007/s11010-008-9770-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 04/07/2008] [Indexed: 01/26/2023]
Abstract
Previous studies show that treatment with a polyunsaturated fatty acid, arachidonic acid (AA), or high concentrations of cycloleucine, an inhibitor of methionine adenosyltransferase (MAT), which lowers levels of S-adenosyl-L-methionine (SAM), increased toxicity in hepatocytes from pyrazole-treated rats which expressed high levels of cytochrome P450 2E1 (CYP2E1). In this study, I used concentrations of cycloleucine or AA, which by themselves do not produce any toxicity, to evaluate whether a decrease in SAM sensitizes hepatocytes to AA toxicity, especially in hepatocytes enriched in CYP2E1. Levels of SAM were lower by 50% in hepatocytes from pyrazole- compared to saline-treated rats. Cycloleucine treatment caused a 50% decline in SAM levels with both hepatocyte preparations and SAM levels were lowest in the pyrazole-treated hepatocytes. The combination of cycloleucine plus AA produced some toxicity and apoptosis in hepatocytes from saline-treated rats but increased toxicity and apoptosis was found in the hepatocytes from pyrazole-treated rats. Cytotoxicity could be prevented by incubation with SAM, the antioxidant trolox, and the mitochondrial permeability transition inhibitor trifluoperazine. The enhanced cytotoxicity could also be protected by treating rats with chlormethiazole, a specific inhibitor of CYP2E1, thus validating the role of CYP2E1. Cycloleucine plus AA treatment elevated production of reactive oxygen species (ROS) and lipid peroxidation to greater extents with the hepatocytes from pyrazole-treated rats than that from the saline-treated rats. I hypothesize that increased production of ROS by hepatocytes enriched in CYP2E1 potentiates AA-induced lipid peroxidation and toxicity when hepatoprotective levels of SAM are lowered. Such interactions, e.g. induction of CYP2E1, decline in SAM and polyunsaturated fatty acid-induced lipid peroxidation, may contribute to alcohol-induced liver injury.
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Li J, Bardag-Gorce F, Dedes J, French BA, Amidi F, Oliva J, French SW. S-adenosylmethionine prevents Mallory Denk body formation in drug-primed mice by inhibiting the epigenetic memory. Hepatology 2008; 47:613-24. [PMID: 18098314 PMCID: PMC2874456 DOI: 10.1002/hep.22029] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
UNLABELLED In previous studies, microarray analysis of livers from mice fed diethyl-1,4-dihydro-2,4,6-trimethyl-3,5-pyridine decarboxylate (DDC) for 10 weeks followed by 1 month of drug withdrawal (drug-primed mice) and then 7 days of drug refeeding showed an increase in the expression of numerous genes referred to here as the molecular cellular memory. This memory predisposes the liver to Mallory Denk body formation in response to drug refeeding. In the current study, drug-primed mice were refed DDC with or without a daily dose of S-adenosylmethionine (SAMe; 4 g/kg of body weight). The livers were studied for evidence of oxidative stress and changes in gene expression with microarray analysis. SAMe prevented Mallory Denk body formation in vivo. The molecular cellular memory induced by DDC refeeding lasted for 4 months after drug withdrawal and was not manifest when SAMe was added to the diet in the in vivo experiment. Liver cells from drug-primed mice spontaneously formed Mallory Denk bodies in primary tissue cultures. SAMe prevented Mallory Denk bodies when it was added to the culture medium. CONCLUSION SAMe treatment prevented Mallory Denk body formation in vivo and in vitro by preventing the expression of a molecular cellular memory induced by prior DDC feeding. No evidence for the involvement of oxidative stress in induction of the memory was found. The molecular memory included the up-regulation of the expression of genes associated with the development of liver cell preneoplasia.
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Affiliation(s)
- Jun Li
- Harbor-UCLA Medical Center, Torrance, CA 90509, USA
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Xie ZY, Luo ZJ, Zhang JX. Progress in diagnosis and treatment of cholestasis. Shijie Huaren Xiaohua Zazhi 2007; 15:3669-3673. [DOI: 10.11569/wcjd.v15.i35.3669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cholestasis can be considered a clinically frequent syndrome caused by complicated factors. Although investigation of cholestasis has been carried out at molecular biology level its pathogenesis can be more clearly recognized. However, the diagnosis and management of intrahepatic cholestasis has not improved. How to identify the pathophysiological and pharmacological targets of cholestatic liver disease is a challenging issue facing clinicians, pathophysiologists and pharmacologists.
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Zhuge J, Cederbaum AI. Depletion of S-adenosyl-l-methionine with cycloleucine potentiates cytochrome P450 2E1 toxicity in primary rat hepatocytes. Arch Biochem Biophys 2007; 466:177-85. [PMID: 17640612 PMCID: PMC2040067 DOI: 10.1016/j.abb.2007.06.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Accepted: 06/12/2007] [Indexed: 12/13/2022]
Abstract
S-Adenosyl-l-methionine (SAM) is the principal biological methyl donor. Methionine adenosyltransferase (MAT) catalyzes the only reaction that generates SAM. Hepatocytes were treated with cycloleucine, an inhibitor of MAT, to evaluate whether hepatocytes enriched in cytochrome P450 2E1 (CYP2E1) were more sensitive to a decline in SAM. Cycloleucine decreased SAM and glutathione (GSH) levels and induced cytotoxicity in hepatocytes from pyrazole-treated rats (with an increased content of CYP2E1) to a greater extent as compared to hepatocytes from saline-treated rats. Apoptosis caused by cycloleucine in pyrazole hepatocytes appeared earlier and was more pronounced than control hepatocytes and could be prevented by incubation with SAM, glutathione reduced ethyl ester and antioxidants. The cytotoxicity was prevented by treating rats with chlormethiazole, a specific inhibitor of CYP2E1. Cycloleucine induced greater production of reactive oxygen species (ROS) in pyrazole hepatocytes than in control hepatocytes, and treatment with SAM, Trolox, and chlormethiazole lowered ROS formation. In conclusion, lowering of hepatic SAM levels produced greater toxicity and apoptosis in hepatocytes enriched in CYP2E1. This is due to elevated ROS production by CYP2E1 coupled to lower levels of hepatoprotective SAM and GSH. We speculate that such interactions e.g. induction of CYP2E1, decline in SAM and GSH may contribute to alcohol liver toxicity.
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Affiliation(s)
- Jian Zhuge
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, NY 10029, USA
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Tarantino G, Saldalamacchia G, Conca P, Arena A. Non-alcoholic fatty liver disease: further expression of the metabolic syndrome. J Gastroenterol Hepatol 2007; 22:293-303. [PMID: 17295757 DOI: 10.1111/j.1440-1746.2007.04824.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Non-alcoholic fatty liver disease has been associated with metabolic disorders, including central obesity, dyslipidemia, hypertension and hyperglycemia. Metabolic syndrome, obesity, and insulin resistance are major risk factors in the pathogenesis of non-alcoholic fatty liver disease. Non-alcoholic fatty liver disease refers to a wide spectrum of liver damage, ranging from simple steatosis to non-alcoholic steatohepatitis, advanced fibrosis and cirrhosis.
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Affiliation(s)
- Giovanni Tarantino
- Department of Clinical and Experimental Medicine, Federico II University Medical School, Naples, Italy.
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