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Li Y, Liang N, Tang T, Zheng Z, Chen M, Mo J, Zhang N, Liao S, Lei Y, Wu Y, Lan C, Ding H, Du B, Feng M, Wang X, Li X, Huang Y, Lu C, Tang S, Li X. Low-dose benzo[a]pyrene exposure induces hepatic lipid deposition through LCMT1/PP2Ac-mediated autophagy inhibition. Food Chem Toxicol 2023; 179:113986. [PMID: 37579989 DOI: 10.1016/j.fct.2023.113986] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/09/2023] [Accepted: 08/11/2023] [Indexed: 08/16/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a progressive disorder of liver metabolism and has become the most common chronic liver disease worldwide. Benzo[a]pyrene (BaP) is recognized as a potent carcinogen, but the effect of low-dose BaP on the development of NAFLD has not been well-studied, and its molecular mechanism is still unknown. In this study, we demonstrated that low-dose BaP induced hepatic steatosis in a mouse model with a notable increase in hepatic lipid content. Interestingly, mRNA expression of genes related to fatty acids uptake or synthesis was not significantly altered after BaP exposure. Instead, we found that low-dose BaP promoted lipid deposition in primary mouse hepatocytes by inhibiting autophagy, which was regulated through Leucine carboxyl methyltransferase-1 (LCMT1) mediated Protein Phosphatases 2A subunit C (PP2Ac) methylation. The role of LCMT1 in BaP-induced steatosis was further validated in a liver-specific lcmt1 knockout (L-LCMT1 KO) mouse model. In this study, we provided evidence to support a novel mechanism by which BaP induces the development of hepatic steatosis through PP2Ac mediated autophagy inhibition. These findings provided new insight into the pathogenesis of NAFLD induced by environmental exposure to low-dose BaP.
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Affiliation(s)
- Yunqing Li
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - NingJing Liang
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Tingting Tang
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Zhijian Zheng
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Muting Chen
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Jiao Mo
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Ning Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Simi Liao
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Yu Lei
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Yijie Wu
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Chunhua Lan
- School of Basic Medical Sciences, Guangxi Medical University, Nanning, 530021, China
| | - Huan Ding
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Bingxin Du
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Mei Feng
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Xinhang Wang
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Xiaoying Li
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China
| | - Yue Huang
- Division of Clinical Genetics, Department of Human Genetics, The David Geffen School of Medicine, The University of California-Los Angeles, Los Angeles, CA, USA
| | - Cailing Lu
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China.
| | - Shen Tang
- School of Basic Medical Sciences, Guangxi Medical University, Nanning, 530021, China.
| | - Xiyi Li
- Department of Nutrition and Food Hygiene, School of Public Health, Guangxi Medical University, Nanning, 530021, China; Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, Guangxi Medical University, Nanning, 530021, China.
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Tang YH, Wang YH, Chen CC, Chan CJ, Tsai FJ, Chen SY. Genetic and Functional Effects of Adiponectin in Type 2 Diabetes Mellitus Development. Int J Mol Sci 2022; 23:ijms232113544. [PMID: 36362336 PMCID: PMC9658884 DOI: 10.3390/ijms232113544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/30/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
Diabetes mellitus (DM) is a common chronic metabolic disease, and the C57BLKsJ-db/db mice are good animal models for type 2 diabetes mellitus (T2DM). In this study, Western blotting and immunohistochemistry (IHC) were employed to examine the protein expression of adiponectin in the liver tissues of T2DM mice with different disease courses (4, 16, and 32 weeks). Adiponectin expression reduced in the liver tissues of T2DM mice in different disease courses. The genotypic and allelic frequencies of the adiponectin gene rs1063538 and rs2241766 single nucleotide polymorphisms (SNPs) in a Taiwanese population (570 T2DM patients and 1700 controls) were investigated. Based on the genetic distribution of the rs2241766 locus, the distribution frequency of the T allele in the T2DM group (72.8%) was higher than in the control group (68.8%). Individuals carrying the G allele had a 0.82-fold greater risk of developing T2DM than individuals carrying the T allele. Differences were evident in the genotypic and allelic distributions (p < 0.05). Enzyme-linked immunosorbent assay (ELISA) was used to measure changes in serum adiponectin protein concentrations in the healthy population and in patients with T2DM. Serum adiponectin concentration in patients with T2DM was lower than in the control group. In summary, adiponectin was determined to be a T2DM susceptibility gene and may be involved in T2DM progression.
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Affiliation(s)
- Yu-Hui Tang
- Department of Medical Genetics, China Medical University Hospital, Taichung 40447, Taiwan
| | - Yeh-Han Wang
- Department of Anatomical Pathology, Taipei Institute of Pathology, School of Medicine, National Yang-Ming University, Taipei 112304, Taiwan
| | - Chin-Chang Chen
- Department of Anatomy, School of Medicine, China Medical University, Taichung 40447, Taiwan
| | - Chia-Jung Chan
- Genetics Center, Department of Medical Research, China Medical University Hospital, China Medical University, No. 2, Yuh-Der Road, Taichung 40447, Taiwan
| | - Fuu-Jen Tsai
- Department of Medical Genetics, China Medical University Hospital, Taichung 40447, Taiwan
- Genetics Center, Department of Medical Research, China Medical University Hospital, China Medical University, No. 2, Yuh-Der Road, Taichung 40447, Taiwan
- School of Chinese Medicine, China Medical University, Taichung 40447, Taiwan
- Correspondence: (F.-J.T.); (S.-Y.C.)
| | - Shih-Yin Chen
- Genetics Center, Department of Medical Research, China Medical University Hospital, China Medical University, No. 2, Yuh-Der Road, Taichung 40447, Taiwan
- School of Chinese Medicine, China Medical University, Taichung 40447, Taiwan
- Correspondence: (F.-J.T.); (S.-Y.C.)
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Yang MH, Li WY, Wu CF, Lee YC, Chen AYN, Tyan YC, Chen YMA. Reversal of High-Fat Diet-Induced Non-Alcoholic Fatty Liver Disease by Metformin Combined with PGG, an Inducer of Glycine N-Methyltransferase. Int J Mol Sci 2022; 23:ijms231710072. [PMID: 36077467 PMCID: PMC9456083 DOI: 10.3390/ijms231710072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/27/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a major cause of liver-related morbidities and mortality, and no effective drug treatment currently exists. We aimed to develop a novel treatment strategy to induce the expression of glycine N-methyltransferase (GNMT), which is an important enzyme regulating S-adenosylmethionine metabolism whose expression is downregulated in patients with NAFLD. Because 1,2,3,4,6-pentagalloyl glucose (PGG) is a GNMT inducer, and metformin was shown to upregulate liver mitochondrial GNMT protein expression, the effect of PGG and metformin was evaluated. Biochemical analysis, histopathological examination, immunohistochemical staining, reverse transcription-quantitative PCR (RT-qPCR), Western blotting (WB), proteomic analysis and Seahorse XF Cell Mito Stress Test were performed. The high-fat diet (HFD)-induced NAFLD mice were treated with PGG and metformin. Combination of PGG and metformin nearly completely reversed weight gain, elevation of serum aminotransferases, and hepatic steatosis and steatohepatitis. In addition, the downregulated GNMT expression in liver tissues of HFD-induced NAFLD mice was restored. The GNMT expression was further confirmed by RT-qPCR and WB analysis using both in vitro and in vivo systems. In addition, PGG treatment was shown to increase oxygen consumption rate (OCR) maximum capacity in a dose-dependent manner, and was capable of rescuing the suppression of mitochondrial OCR induced by metformin. Proteomic analysis identified increased expression of glutathione S-transferase mu 4 (GSTM4), heat shock protein 72 (HSP72), pyruvate carboxylase (PYC) and 40S ribosomal protein S28 (RS28) in the metformin plus PGG treatment group. Our findings show that GNMT expression plays an important role in the pathogenesis of NAFLD, and combination of an inducer of GNMT and metformin can be of therapeutic potential for patients with NAFLD.
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Affiliation(s)
- Ming-Hui Yang
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan
- Center of General Education, Shu-Zen Junior College of Medicine and Management, Kaohsiung 821, Taiwan
| | - Wei-You Li
- Laboratory of Important Infectious Diseases and Cancer, Graduate Institute of Biomedical and Pharmacological Science, School of Medicine, Fu Jen Catholic University, New Taipei City 242, Taiwan
| | - Ching-Fen Wu
- Department of Veterinary Medicine, National Chiayi University, Chiayi City 600, Taiwan
| | - Yi-Ching Lee
- Laboratory of Important Infectious Diseases and Cancer, Graduate Institute of Biomedical and Pharmacological Science, School of Medicine, Fu Jen Catholic University, New Taipei City 242, Taiwan
| | - Allan Yi-Nan Chen
- School of Medicine, University of California, Davis, Sacramento, CA 95817, USA
| | - Yu-Chang Tyan
- Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Department of Nuclear Medicine, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
- Graduate Institute of Animal Vaccine Technology, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung 912, Taiwan
- School of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
- Center for Cancer Research, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Research Center for Precision Environmental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 804, Taiwan
- Correspondence: (Y.-C.T.); (Y.-M.A.C.)
| | - Yi-Ming Arthur Chen
- Laboratory of Important Infectious Diseases and Cancer, Graduate Institute of Biomedical and Pharmacological Science, School of Medicine, Fu Jen Catholic University, New Taipei City 242, Taiwan
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County 350, Taiwan
- Correspondence: (Y.-C.T.); (Y.-M.A.C.)
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Nuclear localization dictates hepatocarcinogenesis suppression by glycine N-methyltransferase. Transl Oncol 2021; 15:101239. [PMID: 34649149 PMCID: PMC8517931 DOI: 10.1016/j.tranon.2021.101239] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 01/01/2023] Open
Abstract
GNMT gene expression contributes to determine hepatocellular carcinoma (HCC) prognosis. GNMT expression is genetically determined. Nuclear GNMT binds to CYP1A1, PREX2, PARP1, and NFKB gene promoters and strongly inhibits their expression.
Background GNMT (glycine N-methyltransferase) is a tumor suppressor gene, but the mechanisms mediating its suppressive activity are not entirely known. Methods We investigated the oncosuppressive mechanisms of GNMT in human hepatocellular carcinoma (HCC). GNMT mRNA and protein levels were evaluated by quantitative RT-PCR and immunoblotting. GNMT effect in HCC cell lines was modulated through GNMT cDNA induced overexpression or anti-GNMT siRNA transfection. Results GNMT was expressed at low level in human HCCs with a better prognosis (HCCB) while it was almost absent in fast-growing tumors (HCCP). In HCCB, the nuclear localization of the GNMT protein was much more pronounced than in HCCP. In Huh7 and HepG2 cell lines, GNMT forced expression inhibited the proliferation and promoted apoptosis. At the molecular level, GNMT overexpression inhibited the expression of CYP1A (Cytochrome p450, aromatic compound-inducible), PREX2 (Phosphatidylinositol-3,4,5-trisphosphate-dependent Rac exchange factor 2), PARP1 [Poly (ADP-ribose) polymerase 1], and NFKB (nuclear factor-kB) genes. By chromatin immunoprecipitation, we found GNMT binding to the promoters of CYP1A1, PREX2, PARP1, and NFKB genes resulting in their strong inhibition. These genes are implicated in hepatocarcinogenesis, and are involved in the GNMT oncosuppressive action. Conclusion Overall, the present data indicate that GNMT exerts a multifaceted suppressive action by interacting with various cancer-related genes and inhibiting their expression.
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Zhang W, Guo X, Ren J, Chen Y, Wang J, Gao A. Glycine/glycine N-methyltransferase/sarcosine axis mediates benzene-induced hematotoxicity. Toxicol Appl Pharmacol 2021; 428:115682. [PMID: 34418406 DOI: 10.1016/j.taap.2021.115682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 08/12/2021] [Accepted: 08/14/2021] [Indexed: 11/20/2022]
Abstract
Benzene, an important and widely used industrial chemical, is the cause of different types of blood disorders. However, the mechanisms of benzene-induced hematotoxicity are still unclear. This study aimed to explore the effects of benzene on metabolism, especially in amino acid metabolism, in human peripheral blood B lymphocyte cells (AHH-1 cells) treated with 1,4-benzoquinone (1,4-BQ) and in benzene-exposed population based on the un-targeted and targeted metabolomics platforms. The results showed that 1,4-BQ disturbed the metabolic activity, such as arginine biosynthesis, citrate cycle, glycine, serine, and threonine metabolism pathways, and significantly upregulated the ratio of sarcosine/glycine in vitro. Meanwhile, the targeted metabolomics further showed that the ratio of sarcosine/glycine was also increased in the benzene exposure population. Notably, the expression of glycine N-methyltransferase (GNMT), an enzyme catalyzing the transformation of glycine to sarcosine, was upregulated both in 1,4-BQ treated AHH-1 cells and benzene-exposed workers. These results imply that the glycine/GNMT/sarcosine axis was involved in benzene-induced hematotoxicity. Such evidence will help to develop a better understanding of the underlying mechanism of benzene-induced hematotoxicity at the level of amino acid metabolism.
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Affiliation(s)
- Wei Zhang
- Department of Occupational Health and Environmental Health, School of Public Health, Capital Medical University, Beijing 100069, PR China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, PR China
| | - Xiaoli Guo
- Department of Occupational Health and Environmental Health, School of Public Health, Capital Medical University, Beijing 100069, PR China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, PR China
| | - Jing Ren
- Department of Occupational Health and Environmental Health, School of Public Health, Capital Medical University, Beijing 100069, PR China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, PR China
| | - Yujiao Chen
- Department of Occupational Health and Environmental Health, School of Public Health, Capital Medical University, Beijing 100069, PR China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, PR China
| | - Jingyu Wang
- Department of Occupational Health and Environmental Health, School of Public Health, Capital Medical University, Beijing 100069, PR China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, PR China
| | - Ai Gao
- Department of Occupational Health and Environmental Health, School of Public Health, Capital Medical University, Beijing 100069, PR China; Beijing Key Laboratory of Environmental Toxicology, Capital Medical University, Beijing 100069, PR China.
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Sou NL, Huang YH, Chen DY, Chen YM, Tang FY, Ko HA, Fan YH, Lin YY, Wang YC, Chih HM, Shane B, Huang WN, Chiang EPI. Folinate Supplementation Ameliorates Methotrexate Induced Mitochondrial Formate Depletion In Vitro and In Vivo. Int J Mol Sci 2021; 22:1350. [PMID: 33572934 PMCID: PMC7866403 DOI: 10.3390/ijms22031350] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 01/25/2021] [Accepted: 01/26/2021] [Indexed: 12/13/2022] Open
Abstract
(1) Background: Antifolate methotrexate (MTX) is the most common disease-modifying antirheumatic drug (DMARD) for treating human rheumatoid arthritis (RA). The mitochondrial-produced formate is essential for folate-mediated one carbon (1C) metabolism. The impacts of MTX on formate homeostasis in unknown, and rigorously controlled kinetic studies can greatly help in this regard. (2) Methods: Combining animal model (8-week old female C57BL/6JNarl mice, n = 18), cell models, stable isotopic tracer studies with gas chromatography/mass spectrometry (GC/MS) platforms, we systematically investigated how MTX interferes with the partitioning of mitochondrial and cytosolic formate metabolism. (3) Results: MTX significantly reduced de novo deoxythymidylate (dTMP) and methionine biosyntheses from mitochondrial-derived formate in cells, mouse liver, and bone marrow, supporting our postulation that MTX depletes mitochondrial 1C supply. Furthermore, MTX inhibited formate generation from mitochondria glycine cleavage system (GCS) both in vitro and in vivo. Folinate selectively rescued 1C metabolic pathways in a tissue-, cellular compartment-, and pathway-specific manner: folinate effectively reversed the inhibition of mitochondrial formate-dependent 1C metabolism in mouse bone marrow (dTMP, methionine, and GCS) and cells (dTMP and GCS) but not methionine synthesis in liver/liver-derived cells. Folinate failed to fully recover hepatic mitochondrial-formate utilization for methionine synthesis, suggesting that the efficacy of clinical folinate rescue in MTX therapy on hepatic methionine metabolism is poor. (4) Conclusion: Conducting studies in mouse and cell models, we demonstrate novel findings that MTX specifically depletes mitochondrial 1C supply that can be ameliorated by folinate supplementation except for hepatic transmethylation. These results imply that clinical use of low-dose MTX may particularly impede 1C metabolism via depletion of mitochondrial formate. The MTX induced systematic and tissue-specific formate depletion needs to be addressed more carefully, and the efficacy of folinate with respect to protecting against such depletion deserves to be evaluated in medical practice.
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Grants
- 108-2321-B-005-004 Ministry of Science and Technology, Taiwan
- 107-2320-B005-003-MY3 Ministry of Science and Technology, Taiwan
- 107-2621-M005-008-MY3 Ministry of Science and Technology, Taiwan
- 107-2321-B-005-009 Ministry of Science and Technology, Taiwan
- 108-2321-B-005 -004 Ministry of Science and Technology, Taiwan
- 107-2320-B039-008-MY3 Ministry of Science and Technology, Taiwan
- 104-2320-B-039-041-MY3 Ministry of Science and Technology, Taiwan
- CMU103-ASIA-20 China Medical University, Taiwan
- CMU103-S-46 China Medical University, Taiwan
- CMU104-S-32 China Medical University, Taiwan
- 997608 Taipei Veterans General Hospital
- 1077602 Taipei Veterans General Hospital
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Affiliation(s)
- Nga-Lai Sou
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (N.-L.S.); (Y.-H.H.); (H.-A.K.); (Y.-H.F.); (Y.-Y.L.); (Y.-C.W.); (H.-M.C.)
- Innovation and Development Center of Sustainable Agriculture (IDCSA), National Chung Hsing University (NCHU), Taichung 402, Taiwan
| | - Yu-Hsuan Huang
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (N.-L.S.); (Y.-H.H.); (H.-A.K.); (Y.-H.F.); (Y.-Y.L.); (Y.-C.W.); (H.-M.C.)
- Innovation and Development Center of Sustainable Agriculture (IDCSA), National Chung Hsing University (NCHU), Taichung 402, Taiwan
| | - Der-Yuan Chen
- Allergy Immunology Rheumatology, Taichung Veterans General Hospital (TVGH), Taichung 402, Taiwan; (D.-Y.C.); (Y.-M.C.); (W.-N.H.)
- Allergy Immunology Rheumatology, China Medical University Hospital, Taichung 402, Taiwan
| | - Yi-Ming Chen
- Allergy Immunology Rheumatology, Taichung Veterans General Hospital (TVGH), Taichung 402, Taiwan; (D.-Y.C.); (Y.-M.C.); (W.-N.H.)
| | - Feng-Yao Tang
- Department of Nutrition, China Medical University, Taichung 402, Taiwan;
| | - Hsin-An Ko
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (N.-L.S.); (Y.-H.H.); (H.-A.K.); (Y.-H.F.); (Y.-Y.L.); (Y.-C.W.); (H.-M.C.)
| | - Yi-Hsuan Fan
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (N.-L.S.); (Y.-H.H.); (H.-A.K.); (Y.-H.F.); (Y.-Y.L.); (Y.-C.W.); (H.-M.C.)
| | - Yi-Ying Lin
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (N.-L.S.); (Y.-H.H.); (H.-A.K.); (Y.-H.F.); (Y.-Y.L.); (Y.-C.W.); (H.-M.C.)
| | - Yi-Cheng Wang
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (N.-L.S.); (Y.-H.H.); (H.-A.K.); (Y.-H.F.); (Y.-Y.L.); (Y.-C.W.); (H.-M.C.)
| | - Hui-Ming Chih
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (N.-L.S.); (Y.-H.H.); (H.-A.K.); (Y.-H.F.); (Y.-Y.L.); (Y.-C.W.); (H.-M.C.)
- Department of Nursing and Pediatrics, Taichung Veterans General Hospital (TVGH), Taichung 402, Taiwan
| | - Barry Shane
- Nutritional Sciences and Toxicology, UC Berkeley, Berkeley, CA 94701, USA;
| | - Wen-Nan Huang
- Allergy Immunology Rheumatology, Taichung Veterans General Hospital (TVGH), Taichung 402, Taiwan; (D.-Y.C.); (Y.-M.C.); (W.-N.H.)
| | - En-Pei Isabel Chiang
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (N.-L.S.); (Y.-H.H.); (H.-A.K.); (Y.-H.F.); (Y.-Y.L.); (Y.-C.W.); (H.-M.C.)
- Innovation and Development Center of Sustainable Agriculture (IDCSA), National Chung Hsing University (NCHU), Taichung 402, Taiwan
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Tan YL, Sou NL, Tang FY, Ko HA, Yeh WT, Peng JH, Chiang EPI. Tracing Metabolic Fate of Mitochondrial Glycine Cleavage System Derived Formate In Vitro and In Vivo. Int J Mol Sci 2020; 21:ijms21228808. [PMID: 33233834 PMCID: PMC7699879 DOI: 10.3390/ijms21228808] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/04/2020] [Accepted: 11/05/2020] [Indexed: 02/07/2023] Open
Abstract
Folate-mediated one-carbon (1C) metabolism is a major target of many therapies in human diseases. Studies have focused on the metabolism of serine 3-carbon as it serves as a major source for 1C units. The serine 3-carbon enters the mitochondria transferred by folate cofactors and eventually converted to formate and serves as a major building block for cytosolic 1C metabolism. Abnormal glycine metabolism has been reported in many human pathological conditions. The mitochondrial glycine cleavage system (GCS) catalyzes glycine degradation to CO2 and ammonium, while tetrahydrofolate (THF) is converted into 5,10-methylene-THF. GCS accounts for a substantial proportion of whole-body glycine flux in humans, yet the particular metabolic route of glycine 2-carbon recycled from GCS during mitochondria glycine decarboxylation in hepatic or bone marrow 1C metabolism is not fully investigated, due to the limited accessibility of human tissues. Labeled glycine at 2-carbon was given to humans and primary cells in previous studies for investigating its incorporations into purines, its interconversion with serine, or the CO2 production in the mitochondria. Less is known on the metabolic fate of the glycine 2-carbon recycled from the GCS; hence, a model system tracing its metabolic fate would help in this regard. We took the direct approach of isotopic labeling to further explore the in vitro and in vivo metabolic fate of the 2-carbon from [2-13C]glycine and [2-13C]serine. As the 2-carbon of glycine and serine is decarboxylated and catabolized via the GCS, the original 13C-labeled 2-carbon is transferred to THF and yield methyleneTHF in the mitochondria. In human hepatoma cell-lines, 2-carbon from glycine was found to be incorporated into deoxythymidine (dTMP, dT + 1), M + 3 species of purines (deoxyadenine, dA and deoxyguanine, dG), and methionine (Met + 1). In healthy mice, incorporation of GCS-derived formate from glycine 2-carbon was found in serine (Ser + 2 via cytosolic serine hydroxy methyl transferase), methionine, dTMP, and methylcytosine (mC + 1) in bone marrow DNA. In these experiments, labeled glycine 2-carbon directly incorporates into Ser + 1, A + 2, and G + 2 (at C2 and C8 of purine) in the cytosol. It is noteworthy that since the serine 3-carbon is unlabeled in these experiments, the isotopic enrichments in dT + 1, Ser + 2, dA + 3, dG + 3, and Met + 1 solely come from the 2-carbon of glycine/serine recycled from GCS, re-enters the cytosolic 1C metabolism as formate, and then being used for cytosolic syntheses of serine, dTMP, purine (M + 3) and methionine. Taken together, we established model systems and successfully traced the metabolic fate of mitochondrial GCS-derived formate from glycine 2-carbon in vitro and in vivo. Nutritional supply significantly alters formate generation from GCS. More GCS-derived formate was used in hepatic serine and methionine syntheses, whereas more GCS-derived formate was used in dTMP synthesis in the bone marrow, indicating that the utilization and partitioning of GCS-derived 1C unit are tissue-specific. These approaches enable better understanding concerning the utilization of 1C moiety generated from mitochondrial GCS that can help to further elucidate the role of GCS in human disease development and progression in future applications. More studies on GCS using these approaches are underway.
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Affiliation(s)
- Yee-Ling Tan
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (Y.-L.T.); (N.-L.S.); (H.-A.K.); (W.-T.Y.); (J.-H.P.)
| | - Nga-Lai Sou
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (Y.-L.T.); (N.-L.S.); (H.-A.K.); (W.-T.Y.); (J.-H.P.)
- Innovation and Development Center of Sustainable Agriculture (IDCSA), National Chung Hsing University (NCHU), Taichung 402, Taiwan
| | - Feng-Yao Tang
- Department of Nutrition, China Medical University, Taichung 402, Taiwan;
| | - Hsin-An Ko
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (Y.-L.T.); (N.-L.S.); (H.-A.K.); (W.-T.Y.); (J.-H.P.)
| | - Wei-Ting Yeh
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (Y.-L.T.); (N.-L.S.); (H.-A.K.); (W.-T.Y.); (J.-H.P.)
| | - Jian-Hau Peng
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (Y.-L.T.); (N.-L.S.); (H.-A.K.); (W.-T.Y.); (J.-H.P.)
- Innovation and Development Center of Sustainable Agriculture (IDCSA), National Chung Hsing University (NCHU), Taichung 402, Taiwan
- Microbial Genomics Ph.D. Graduate Program, National Chung Hsing University (NCHU), Taichung 402, Taiwan
| | - En-Pei Isabel Chiang
- Food Science and Biotechnology, National Chung Hsing University (NCHU), Taichung 402, Taiwan; (Y.-L.T.); (N.-L.S.); (H.-A.K.); (W.-T.Y.); (J.-H.P.)
- Department of Nutrition, China Medical University, Taichung 402, Taiwan;
- Microbial Genomics Ph.D. Graduate Program, National Chung Hsing University (NCHU), Taichung 402, Taiwan
- Department of Food Science and Biotechnology, National Chung Hsing University, Taichung 402, Taiwan
- Correspondence: ; Tel.: +886-4-22853049; Fax: +886-4-22876211
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8
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Wang R, Li F, Ruan W, Tai Y, Cai H, Yang Y. Removal and degradation pathway analysis of 17β-estradiol from raw domestic wastewater using immobilised functional microalgae under repeated loading. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2020.107700] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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9
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Chen CH, Wang YH, Tsai SF, Yu TM, Chen SY, Tsai FJ. Antizyme inhibitor 1 genetic polymorphisms associated with diabetic patients validated in the livers of diabetic mice. Exp Ther Med 2019; 18:3139-3146. [PMID: 31572554 DOI: 10.3892/etm.2019.7919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 06/06/2019] [Indexed: 11/05/2022] Open
Abstract
Diabetes mellitus (DM) is a complex disease caused by absolute or relative insulin deficiency. The C57BLKsJ-db/db mouse model is a useful animal model for studying type 2 DM (T2DM). The present study investigated the association between an antizyme inhibitor 1 (AZIN1) gene polymorphism (rs1062048) and T2DM susceptibility in 2,270 Taiwanese individuals (570 patients with T2DM and 1,700 controls). Additionally, the present study investigated AZIN1 gene and protein expression in the liver tissues of mice in three age groups (4, 16 and 32 weeks) through reverse transcription-quantitative PCR, western blotting and immunohistochemistry. The data indicated that the genotype frequency distribution of the rs1062048 single-nucleotide polymorphism differed significantly between the patients with T2DM and controls (P<0.05). Furthermore, gene and protein expression levels of AZIN1 were significantly lower in early stage and late stage T2DM mouse liver samples than in control samples. Overall, the data suggested that AZIN1 expression is involved in T2DM development.
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Affiliation(s)
- Cheng-Hsu Chen
- Department of Medical Research, Division of Basic Medical Sciences, Taichung Veterans General Hospital, Taichung 40705, Taiwan, R.O.C.,Department of Internal Medicine, Division of Nephrology, Taichung Veterans General Hospital, Taichung 40705, Taiwan, R.O.C.,Department of Life Science, Tunghai University, Taichung 40705, Taiwan, R.O.C.,School of Medicine, China Medical University, Taichung 40402, Taiwan, R.O.C
| | - Yeh-Han Wang
- Department of Anatomical Pathology, Taipei Institute of Pathology, School of Medicine, National Yang-Ming University, 11221 Taipei, Taiwan, R.O.C
| | - Shang-Feng Tsai
- Department of Internal Medicine, Division of Nephrology, Taichung Veterans General Hospital, Taichung 40705, Taiwan, R.O.C.,Department of Life Science, Tunghai University, Taichung 40705, Taiwan, R.O.C.,Department of Internal Medicine, School of Medicine, National Yang-Ming University, 11221 Taipei, Taiwan, R.O.C
| | - Tung-Min Yu
- Department of Internal Medicine, Division of Nephrology, Taichung Veterans General Hospital, Taichung 40705, Taiwan, R.O.C.,School of Medicine, China Medical University, Taichung 40402, Taiwan, R.O.C
| | - Shih-Yin Chen
- School of Chinese Medicine, China Medical University, Taichung 40402, Taiwan, R.O.C.,Genetics Center, Medical Research, China Medical University Hospital, Taichung 40447, Taiwan, R.O.C
| | - Fuu-Jen Tsai
- School of Chinese Medicine, China Medical University, Taichung 40402, Taiwan, R.O.C.,Genetics Center, Medical Research, China Medical University Hospital, Taichung 40447, Taiwan, R.O.C.,Department of Medical Genetics, China Medical University Hospital, Taichung 40447, Taiwan, R.O.C
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10
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Pakzad Toochaei S, Ghasempouri SM, Riyahi Bakhtiari A, Khodabandeh S. Global DNA methylation changes in rock pigeon (Columba livia) as a sentinel species due to polycyclic aromatic hydrocarbons exposure in Tehran (Iran) as a megacity. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:26090-26101. [PMID: 31280440 DOI: 10.1007/s11356-019-05642-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 05/29/2019] [Indexed: 06/09/2023]
Abstract
Global DNA methylation, as an epigenetic modifications, can be a promising genomic marker for monitoring the contaminants and predicting their adverse health effects. The study aims to assess the effects of 16 PAH concentration on the altered DNA methylation levels in the kidney and liver of rock pigeon (Columba livia), as a sentinel species, from Tehran megacity as well as 40 days benzo(a)pyrene in vitro exposure: (0.1, 2.5, 5, 7.5, and 10 mg kg-1 bw). Data indicated that the total LMW-PAH (low molecular weight PAHs) group (120.22, 121.34, 103.69, and 128.79 ng g-1 dw in liver, kidney, skin, and muscle, respectively) in the Tehran samples have higher levels than the other PAHs groups. In addition, the DNA methylation level had negative relation with the total amount of PAHs in liver and kidney. A comparatively higher global DNA hypomethylation (by 8.65% in liver and 3.76% in kidney) was observed in birds exposed to B(a)P. Our results lead us to suggest that DNA hypomethylation in liver and kidney associated with the B(a)P may be useful biomarker discovery (more than the amount of PAH concentration in different tissues of C. livia) in urban areas. In conclusion, based on the overall results assessed, DNA methylation changes in pigeon may show a new target pathway for evaluation of environmental health.
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Affiliation(s)
- Sahel Pakzad Toochaei
- Hamoun International Wetland Research Institute, University of Zabol, 98615-538, Zabol, Iran
| | - Seyed Mahmoud Ghasempouri
- Department of Environmental Science, Faculty of Natural Resources, Tarbiat Modares University, P.O. Box 46414-356, Noor, Iran.
| | - Alireza Riyahi Bakhtiari
- Department of Environmental Science, Faculty of Natural Resources, Tarbiat Modares University, P.O. Box 46414-356, Noor, Iran
| | - Saber Khodabandeh
- Department of Marine Biology, Faculty of Marine Sciences, Tarbiat Modares University, P.O.Box 46414-356, Noor, Iran
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11
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Tumor suppressor gene glycine N-methyltransferase and its potential in liver disorders and hepatocellular carcinoma. Toxicol Appl Pharmacol 2019; 378:114607. [PMID: 31170416 DOI: 10.1016/j.taap.2019.114607] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/28/2019] [Accepted: 05/31/2019] [Indexed: 02/06/2023]
Abstract
Glycine N-methyltransferase is a protein with many functions. In addition to catalyzing the production of sarcosine in the one carbon metabolism pathway, it plays a role in the detoxification of environmental carcinogens such as benzo[a]pyrene, aflatoxin B1, and aristocholic acid. There is also increasing evidence suggesting a role of GNMT deficiency in liver carcinogenesis. In this review, we discuss the role of GNMT in the detoxification of xenobiotics and the mechanism of GNMT suppression during liver tumorigenesis. The protective role of GNMT in the liver allows GNMT to not only serve as a marker of liver disease, but also potentially be applied in the treatment of liver disorders and hepatocellular carcinoma. We describe the potential use of GNMT in gene therapy and we introduce the development of a GNMT promoter reporter assay that can be used to screen medicinal drugs and herbal libraries for natural compounds with anti-cancer properties.
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12
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Yang MH, Yen CH, Chen YF, Fang CC, Li CH, Lee KJ, Lin YH, Weng CH, Liu TT, Huang SF, Teh BT, Chen YMA. Somatic mutations of PREX2 gene in patients with hepatocellular carcinoma. Sci Rep 2019; 9:2552. [PMID: 30796242 PMCID: PMC6385191 DOI: 10.1038/s41598-018-36810-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 11/09/2018] [Indexed: 12/12/2022] Open
Abstract
Characterized with a high recurrence rate and low detection rate, prevention is the best approach to reduce mortality in hepatocellular carcinoma (HCC). The overexpression of Phosphatidylinositol-3,4,5-Trisphosphate Dependent Rac Exchange Factor 2 (PREX2) is observed in various tumors, including HCC; and the frequent PREX2 mutations in melanoma are associated with invasiveness. We sought to identify somatic mutations and the functional changes in mutational signatures of PREX2. Genomic DNA sequencing was performed in 68 HCC samples with three types of hepatitis viral infection status: HBs Ag-positive, anti-HCV Ab-positive, and negative for any hepatitis B or C markers. Stabilities and interactions of proteins as well as cell proliferation and migration were evaluated. Fourteen non-silent point mutations in PREX2 were detected, with 16 of 68 HCC patients harboring at least one non-silent mutation. All mutant forms of PREX2, except for K400f, had an extended half-life compared with wild-type PREX2. Moreover, only the half-life of S1113R was twice that of the wild-type. PREX2 mutant-S1113R also promoted migration and activated the AKT pathway as well as impaired HectH9-mediated ubiquitination. Our study identified a gain-of-function mutation of PREX2 – S1113R in HCC. Such mutation enhanced PREX2 protein stability, promoted cell proliferation, and was associated with aggressiveness of HCC.
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Affiliation(s)
- Ming-Hui Yang
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.,Institute of Biological Chemistry, Academia Sinica, Taipei, 11529, Taiwan.,Master Program in Clinical Pharmacogenomics and Pharmacoproteomics, College of Pharmacy, Taipei Medical University, Taipei, 110, Taiwan
| | - Chia-Hung Yen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.,Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Yen-Fu Chen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Cheng-Chieh Fang
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Chung-Hsien Li
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Kuo-Jui Lee
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Yi-Hsiung Lin
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Chien-Hui Weng
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Tze-Tze Liu
- VYM Genome Research Center, National Yang-Ming University, Taipei, 11221, Taiwan
| | - Shiu-Feng Huang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, 35053, Taiwan
| | - Bin Tean Teh
- Laboratory of Cancer Epigenome, Division of Medical Sciences, National Cancer Centre, Singapore, 169610, Singapore
| | - Yi-Ming Arthur Chen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan. .,Master Program in Clinical Pharmacogenomics and Pharmacoproteomics, College of Pharmacy, Taipei Medical University, Taipei, 110, Taiwan.
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13
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Kant R, Yen CH, Hung JH, Lu CK, Tung CY, Chang PC, Chen YH, Tyan YC, Chen YMA. Induction of GNMT by 1,2,3,4,6-penta-O-galloyl-beta-D-glucopyranoside through proteasome-independent MYC downregulation in hepatocellular carcinoma. Sci Rep 2019; 9:1968. [PMID: 30760754 PMCID: PMC6374375 DOI: 10.1038/s41598-018-37292-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 10/02/2018] [Indexed: 01/26/2023] Open
Abstract
Glycine-N-methyl transferase (GNMT) a tumor suppressor for hepatocellular carcinoma (HCC) plays a crucial role in liver homeostasis. Its expression is downregulated in almost all the tumor tissues of HCC while the mechanism of this downregulation is not yet fully understood. Recently, we identified 1,2,3,4,6-penta-O-galloyl-beta-D-glucopyranoside (PGG) as a GNMT promoter enhancer compound in HCC. In this study, we aimed to delineate the mechanism by which PGG enhances GNMT expression and to investigate its effect on GNMT suppression in HCC. Microarray and pathway enrichment analysis revealed that MYC was a major target of PGG. PGG suppressed MYC mRNA and protein expression in Huh7 and Hep G2 cells in a dose- and time-dependent fashion. Furthermore, MYC expression was also reduced in xenograft tumors in PGG treated mice. Moreover, shRNA-mediated knocked-down or pharmacological inhibition of MYC resulted in a significant induction of GNMT promoter activity and endogenous GNMT mRNA expression in Huh7 cells. In contrast, overexpression of MYC significantly inhibited GNMT promoter activity and endogenous GNMT protein expression. In addition, antibodies against MYC effectively precipitated the human GNMT promoter in a chromatin immunoprecipitation assay. Lastly, GNMT expression was negatively correlated with MYC expression in human HCC samples. Interestingly, PGG not only inhibited MYC gene expression but also promoted MYC protein degradation through proteasome-independent pathways. This work reveals a novel anticancer mechanism of PGG via downregulation of MYC expression and establishes a therapeutic rationale for treatment of MYC overexpressing cancers using PGG. Our data also provide a novel mechanistic understanding of GNMT regulation through MYC in the pathogenesis of HCC.
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Affiliation(s)
- Rajni Kant
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chia-Hung Yen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.,Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan.,Research Center for Natural products and Drug Development (CHY), Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jung-Hsien Hung
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan.,Department and Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan
| | - Chung-Kuang Lu
- National Research Institute of Chinese Medicine, Taipei, Taiwan.,Department of Life Sciences and Institute of Genome Sciences, College of Life Science, National Yang-Ming University, Taipei, Taiwan
| | - Chien-Yi Tung
- VYM Genome Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Pei-Ching Chang
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan.,Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan
| | - Yueh-Hao Chen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yu-Chang Tyan
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan. .,Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. .,Department of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan. .,Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung, Taiwan. .,Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. .,Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
| | - Yi-Ming Arthur Chen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan. .,Master Program in Clinical Pharmacogenomics and Pharmacoproteomics, College of Pharmacy, Taipei Medical University, Taipei, Taiwan.
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14
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Yang MH, Liao CC, Hung JH, Lai XT, Yen CH, Chen YMA. Utilizing proteomic approach to identify nuclear translocation related serine kinase phosphorylation site of GNMT as downstream effector for benzo[a]pyrene. J Food Drug Anal 2019; 27:603-609. [PMID: 30987732 PMCID: PMC9296196 DOI: 10.1016/j.jfda.2018.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 01/18/2023] Open
Abstract
Glycine N-methyltransferase (GNMT) protein is highly expressed in certain tissues, such as liver, pancreas, and prostate. GNMT serves multiple roles which include a methyl group transfer enzyme and a liver tumor suppressor. Benzo(a)pyrene (BaP), a family member of polycyclic aromatic hydrocarbon (PAH), is a known environmental carcinogen found in coal tar, tobacco smoke, barbecued food and incomplete combustion of auto fuel. BaP recruits cytochrome P450 to transform itself into benzo(a)pyrene-7,8-diol-9,10-epoxide (B(a) PDE), which covalently interacts with DNA causing tumorigenesis. BaP can be detoxified through GNMT and induces GNMT translocation into the cellular nucleus. GNMT translocation is accompanied by phosphorylation, but the role of phosphorylation in GNMT remains to be explored. Using liquid chromatography coupled with tandem mass spectrometry, this study identified serine 9 of GNMT as the phosphorylation site upon BaP treatment. When serine 9 was mutated and lost the capability to be phosphorylated, the occurrence of BaP-induced GNMT nuclear translocation was dramatically decreased. Also, this mutant from of GNMT lost the ability of phosphorylation and increased cytochrome P450 1A1 (Cyp1a) expression upon BaP treatment. In addition, protein kinase C (PKC) and c-Jun NH2-terminal kinase (JNK) may be required for such phosphorylation. Further characterization of phosphorylated GNMT for its link to BaP may bring new insights into chemical detoxification.
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Affiliation(s)
- Ming-Hui Yang
- Institute of Biological Chemistry, Academia Sinica, Taipei, 11529,
Taiwan
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung 80708,
Taiwan
- Master Program in Clinical Pharmacogenomics and Pharmacoproteomics, College of Pharmacy, Taipei Medical University, Taipei, 11031,
Taiwan
- Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung 807,
Taiwan
| | - Chen-Chung Liao
- Proteomics Research Center, National Yang-Ming University, Taipei 11221,
Taiwan
| | - Jung-Hsien Hung
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung 80708,
Taiwan
| | - Xiu-Ting Lai
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 11221,
Taiwan
| | - Chia-Hung Yen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung 80708,
Taiwan
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708,
Taiwan
- Research Center for Natural products and Drug Development, Kaohsiung Medical University, Kaohsiung,
Taiwan
- Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung,
Taiwan
- Corresponding author. E-mail addresses: (C.-H. Yen), (Y.-M.A. Chen)
| | - Yi-Ming Arthur Chen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung 80708,
Taiwan
- Master Program in Clinical Pharmacogenomics and Pharmacoproteomics, College of Pharmacy, Taipei Medical University, Taipei, 11031,
Taiwan
- Corresponding author. No. 100, Shih-Chuan Ist Rd, Kaohsiung City, 80708, Taiwan. Fax: +886 7 3222783
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15
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Fang CC, Wu CF, Liao YJ, Huang SF, Chen M, Chen YMA. AAV serotype 8-mediated liver specific GNMT expression delays progression of hepatocellular carcinoma and prevents carbon tetrachloride-induced liver damage. Sci Rep 2018; 8:13802. [PMID: 30217986 PMCID: PMC6138656 DOI: 10.1038/s41598-018-30800-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 07/24/2018] [Indexed: 02/08/2023] Open
Abstract
Glycine N-methyltransferase (GNMT) is abundantly expressed in normal livers and plays a protective role against tumor formation. GNMT depletion leads to progression of hepatocellular carcinoma (HCC). In this study, we investigated the activity of ectopic GNMT delivered using recombinant adeno-associated virus (AAV) gene therapy in mouse models of liver cirrhosis and HCC. Injection of AAV serotype 8 (AAV8) vector carrying the GNMT gene (AAV8-GNMT) in Gnmt−/− mice increased GNMT expression and downregulated pro-inflammatory responses, resulting in reduced liver damage and incidence of liver tumors. Moreover, AAV8-GNMT resulted in the amelioration of carbon tetrachloride (CCl4)-induced liver fibrosis in BALB/c mice. We showed that AAV8-GNMT protected hepatocytes from CCl4-induced liver damage. AAV8-GNMT significantly attenuated the levels of pro-fibrotic markers and increased efficiency of hepatocyte proliferation. These results suggest that correction of hepatic GNMT by gene therapy of AAV8-mediated gene enhancement may provide a potential strategy for preventing and delaying development of liver diseases.
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Affiliation(s)
- Cheng-Chieh Fang
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Ching-Fen Wu
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan.,National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Miaoli, Taiwan
| | - Yi-Jen Liao
- School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Shiu-Feng Huang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, Taiwan
| | - Marcelo Chen
- Department of Urology, Mackay Memorial Hospital, Taipei, Taiwan.,School of Medicine, Mackay Medical College, New Taipei City, Taiwan
| | - Yi-Ming Arthur Chen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan. .,Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan. .,Department of Microbiology and Immunology, Institute of Medical Research and Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
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16
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Simile MM, Latte G, Feo CF, Feo F, Calvisi DF, Pascale RM. Alterations of methionine metabolism in hepatocarcinogenesis: the emergent role of glycine N-methyltransferase in liver injury. Ann Gastroenterol 2018; 31:552-560. [PMID: 30174391 PMCID: PMC6102450 DOI: 10.20524/aog.2018.0288] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 05/02/2018] [Indexed: 12/30/2022] Open
Abstract
The methionine and folate cycles play a fundamental role in cell physiology and their alteration is involved in liver injury and hepatocarcinogenesis. Glycine N-methyltransferase is implicated in methyl group supply, DNA methylation, and nucleotide biosynthesis. It regulates the cellular S-adenosylmethionine/S-adenosylhomocysteine ratio and S-adenosylmethionine-dependent methyl transfer reactions. Glycine N-methyltransferase is absent in fast-growing hepatocellular carcinomas and present at a low level in slower growing HCC ones. The mechanism of tumor suppression by glycine N-methyltransferase is not completely known. Glycine N-methyltransferase inhibits hepatocellular carcinoma growth through interaction with Dep domain-containing mechanistic target of rapamycin (mTor)-interacting protein, a binding protein overexpressed in hepatocellular carcinoma. The interaction of the phosphatase and tensin homolog inhibitor, phosphatidylinositol 3,4,5-trisphosphate-dependent rac exchanger, with glycine N-methyltransferase enhances proteasomal degradation of this exchanger by the E3 ubiquitin ligase HectH. Glycine N-methyltransferase also regulates genes related to detoxification and antioxidation pathways. It supports pyrimidine and purine syntheses and minimizes uracil incorporation into DNA as consequence of folate depletion. However, recent evidence indicates that glycine N-methyltransferase targeted into nucleus still exerts strong anti-proliferative effects independent of its catalytic activity, while its restriction to cytoplasm prevents these effects. Our current knowledge suggest that glycine N-methyltransferase plays a fundamental, even if not yet completely known, role in cellular physiology and highlights the need to further investigate this role in normal and cancer cells.
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Affiliation(s)
- Maria M Simile
- Department of Clinical, Surgical and Experimental Medicine, Division of Experimental Pathology and Oncology (Maria M. Simile, Gavinella Latte, Francesco Feo, Diego F. Calvisi, Rosa M. Pascale), University of Sassari, Sassari, Italy
| | - Gavinella Latte
- Department of Clinical, Surgical and Experimental Medicine, Division of Experimental Pathology and Oncology (Maria M. Simile, Gavinella Latte, Francesco Feo, Diego F. Calvisi, Rosa M. Pascale), University of Sassari, Sassari, Italy
| | - Claudio F Feo
- Department of Clinical, Surgical and Experimental Medicine, Division of Surgery (Claudio F. Feo), University of Sassari, Sassari, Italy
| | - Francesco Feo
- Department of Clinical, Surgical and Experimental Medicine, Division of Experimental Pathology and Oncology (Maria M. Simile, Gavinella Latte, Francesco Feo, Diego F. Calvisi, Rosa M. Pascale), University of Sassari, Sassari, Italy
| | - Diego F Calvisi
- Department of Clinical, Surgical and Experimental Medicine, Division of Experimental Pathology and Oncology (Maria M. Simile, Gavinella Latte, Francesco Feo, Diego F. Calvisi, Rosa M. Pascale), University of Sassari, Sassari, Italy
| | - Rosa M Pascale
- Department of Clinical, Surgical and Experimental Medicine, Division of Experimental Pathology and Oncology (Maria M. Simile, Gavinella Latte, Francesco Feo, Diego F. Calvisi, Rosa M. Pascale), University of Sassari, Sassari, Italy
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17
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Chang MM, Lin CN, Fang CC, Chen M, Liang PI, Li WM, Yeh BW, Cheng HC, Huang BM, Wu WJ, Chen YMA. Glycine N-methyltransferase inhibits aristolochic acid nephropathy by increasing CYP3A44 and decreasing NQO1 expression in female mouse hepatocytes. Sci Rep 2018; 8:6960. [PMID: 29725048 PMCID: PMC5934382 DOI: 10.1038/s41598-018-22298-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 02/19/2018] [Indexed: 12/12/2022] Open
Abstract
Plants containing aristolochic acids (AA) are nephrotoxins. Glycine N-methyltransferase (GNMT) acts to bind environmental toxins such as benzo(a)pyrene and aflatoxin B1, translocate into nucleus, and alter hepatic metabolism. This study aims to determine the role of GNMT in AA-induced nephropathy. We established an AA nephropathy mouse model and found that AA type I (AAI)-induced nephropathy at a lower concentration in male than in female mice, implying sex differences in AAI resistance. Microarray analysis and AAI-treated mouse models showed that GNMT moderately reduced AAI-induced nephropathy by lowering the upregulated level of NQO1 in male, but significantly improved the nephropathy additionally by increasing Cyp3A44/3A41 in female. The protective effects of GNMT were absent in female GNMT knockout mice, in which re-expression of hepatic GNMT significantly decreased AAI-induced nephropathy. Mechanism-wise, AAI enhanced GNMT nuclear translocation, resulting in GNMT interaction with the promoter region of the genes encoding Nrf2 and CAR/PXR, the transcription factors for NQO1 and CYP3A44/3A41, respectively. Unlike the preference for Nrf2/NQO1 transcriptions at lower levels of GNMT, overexpression of GNMT preferred CAR/PXR/CYP3A44/3A41 transcriptions and alleviated kidney injury upon AAI treatment. In summary, hepatic GNMT protected mice from AAI nephropathy by enhancing CAR/PXR/CYP3A44/3A41 transcriptions and reducing Nrf2/NQO1 transcriptions.
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Affiliation(s)
- Ming-Min Chang
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chang-Ni Lin
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Cheng-Chieh Fang
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Marcelo Chen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Urology, Mackay Memorial Hospital, Taipei, Taiwan.,Department of Cosmetic Applications and Management, Mackay Junior College of Medicine, Nursing and Management, Taipei, Taiwan
| | - Peir-In Liang
- Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Wei-Ming Li
- Pingtung Hospital, Ministry of Health and Welfare, Executive Yuan, Pingtung, Taiwan.,Department of Urology, School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Bi-Wen Yeh
- Department of Urology, School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Hung-Chi Cheng
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Bu-Miin Huang
- Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wen-Jeng Wu
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Urology, School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.,Department of Urology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung, Taiwan.,Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yi-Ming Arthur Chen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan. .,Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
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18
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Cheng CH, Liang HY, Luo SW, Wang AL, Ye CX. The protective effects of vitamin C on apoptosis, DNA damage and proteome of pufferfish (Takifugu obscurus) under low temperature stress. J Therm Biol 2017; 71:128-135. [PMID: 29301681 DOI: 10.1016/j.jtherbio.2017.11.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 10/21/2017] [Accepted: 11/12/2017] [Indexed: 11/28/2022]
Abstract
The aim of this study was to investigate the protective effects of vitamin C on apoptosis, DNA damage and proteome of pufferfish under low temperature stress. Six diets were formulated to contain 2.60, 48.90, 95.50, 189.83, 382.40, 779.53mg/kg vitamin C. After 8-week feeding trial, fish were exposed to low temperature challenge. The results showed that pufferfish receiving vitamin C diet exhibited a significant decrease in ROS production (48.9-189.83mg/kg vitamin C diet groups), cytoplasmic free-Ca2+ concentration (48.9-779.53mg/kg vitamin C diet groups), apoptotic cell ratio (95.5-779.53mg/kg vitamin C diet groups) and DNA damage (189.83-779.53mg/kg vitamin C diet groups) under low temperature stress in comparison with those of control. We also investigated the alteration in protein expression under low temperature stress by a comparative proteomic analysis. The results demonstrated that 24 protein spots showed significantly differential expression in the cold-stress-treated group compared with those of the control group, and 5 protein spots were successfully identified. Furthermore, comparative proteomic analysis revealed that vitamin C could increase expressed proteins related to energy metabolism, immune responses and cytoskeleton. These findings would be helpful to understand the protective effects of vitamin C against cold stress.
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Affiliation(s)
- Chang-Hong Cheng
- Key Laboratory of Aquatic Product Processing, Key Laboratory of South China Sea Fishery Resources Exploitation & Utilization, Ministry of Agriculture, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, Guangdong 510300, PR China
| | - Hai-Yan Liang
- Key Laboratory of Ecology and Environmental Science of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, School of Life Science, South China Normal University, Guangzhou 510631, PR China
| | - Sheng-Wei Luo
- Key Laboratory of Ecology and Environmental Science of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, School of Life Science, South China Normal University, Guangzhou 510631, PR China
| | - An-Li Wang
- Key Laboratory of Ecology and Environmental Science of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, School of Life Science, South China Normal University, Guangzhou 510631, PR China.
| | - Chao-Xia Ye
- Key Laboratory of Ecology and Environmental Science of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, School of Life Science, South China Normal University, Guangzhou 510631, PR China.
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19
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Li CH, Yen CH, Chen YF, Lee KJ, Fang CC, Zhang X, Lai CC, Huang SF, Lin HK, Arthur Chen YM. Characterization of the GNMT-HectH9-PREX2 tripartite relationship in the pathogenesis of hepatocellular carcinoma. Int J Cancer 2017; 140:2284-2297. [PMID: 28205209 DOI: 10.1002/ijc.30652] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 12/15/2016] [Accepted: 02/07/2017] [Indexed: 12/22/2022]
Abstract
The pathogenesis of hepatocellular carcinoma (HCC) involves many molecular pathways. Glycine N-methyltransferase (GNMT) is downregulated in almost all HCC and its gene knockout mice developed HCC with high penetrance. We identified PREX2, a novel PTEN inhibitor, as a GNMT-interacting protein. Such interaction enhanced degradation of PREX2 through an E3 ligase HectH9-mediated proteasomal ubiquitination pathway. Depletion of GNMT or HectH9 resulted in AKT activation in a PREX2 dependent manner and enhanced cell proliferation. An elevated PREX2 protein expression accompanied by activation of AKT was observed in the liver of Gnmt knockout mice. PREX2 protein expression was upregulated in 54.9% of human HCC samples, while its mRNA level was comparable in tumor and tumor-adjacent tissue, suggesting a post-translational alteration of PREX2 expression. Higher level of PREX2 in the tumor tissues was associated with poorer survival. These results reveal a novel mechanism in which GNMT participates in AKT signaling and HCC tumorigenesis by promoting HectH9-mediated PREX2 degradation.
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Affiliation(s)
- Chung-Hsien Li
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Chia-Hung Yen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.,Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Yen-Fu Chen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Kuo-Jui Lee
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Cheng-Chieh Fang
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Xian Zhang
- Department of Cancer Biology, Wake Forest Cancer Center, Wake Forest University, Winston-Salem, NC
| | - Chih-Chung Lai
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Shiu-Feng Huang
- Division of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, 35053, Taiwan
| | - Hui-Kuan Lin
- Department of Cancer Biology, Wake Forest Cancer Center, Wake Forest University, Winston-Salem, NC
| | - Yi-Ming Arthur Chen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.,Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.,Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan
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20
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Kant R, Yen CH, Lu CK, Lin YC, Li JH, Chen YMA. Identification of 1,2,3,4,6-Penta-O-galloyl-β-d-glucopyranoside as a Glycine N-Methyltransferase Enhancer by High-Throughput Screening of Natural Products Inhibits Hepatocellular Carcinoma. Int J Mol Sci 2016; 17:ijms17050669. [PMID: 27153064 PMCID: PMC4881495 DOI: 10.3390/ijms17050669] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 04/25/2016] [Accepted: 04/25/2016] [Indexed: 01/09/2023] Open
Abstract
Glycine N-methyltransferase (GNMT) expression is vastly downregulated in hepatocellular carcinomas (HCC). High rates of GNMT knockout mice developed HCC, while overexpression of GNMT prevented aflatoxin-induced carcinogenicity and inhibited liver cancer cell proliferation. Therefore, in this study, we aimed for the identification of a GNMT inducer for HCC therapy. We established a GNMT promoter-driven luciferase reporter assay as a drug screening platform. Screening of 324 pure compounds and 480 crude extracts from Chinese medicinal herbs resulted in the identification of Paeonia lactiflora Pall (PL) extract and the active component 1,2,3,4,6-penta-O-galloyl-β-d-glucopyranoside (PGG) as a GNMT inducer. Purified PL extract and PGG induced GNMT mRNA and protein expression in Huh7 human hepatoma cells and in xenograft tumors. PGG and PL extract had potent anti-HCC effects both in vitro and in vivo. Furthermore, PGG treatment induced apoptosis in Huh7 cells. Moreover, PGG treatment sensitized Huh7 cells to sorafenib treatment. Therefore, these results indicated that identifying a GNMT enhancer using the GNMT promoter-based assay might be a useful approach to find drugs for HCC. These data also suggested that PGG has therapeutic potential for the treatment of HCC.
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Affiliation(s)
- Rajni Kant
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei 11221, Taiwan.
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
| | - Chia-Hung Yen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
- Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
- Lipid Science and Aging Research Center (CHY), Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
- Research Center for natural products and Drug Development (CHY), Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
| | - Chung-Kuang Lu
- National Research Institute of Chinese Medicine, Taipei 11221, Taiwan.
- Department of Life Sciences and Institute of Genome Sciences, College of Life Science, National Yang-Ming University, Taipei 11221, Taiwan.
| | - Ying-Chi Lin
- School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
- Ph.D. Program in Toxicology, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
| | - Jih-Heng Li
- School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
- Ph.D. Program in Toxicology, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
| | - Yi-Ming Arthur Chen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
- Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung 80708, Taiwan.
- Department of Microbiology and Immunology, Institute of Medical Research and Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
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21
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Li CH, Lin MH, Chu SH, Tu PH, Fang CC, Yen CH, Liang PI, Huang JC, Su YC, Sytwu HK, Chen YMA. Role of glycine N-methyltransferase in the regulation of T-cell responses in experimental autoimmune encephalomyelitis. Mol Med 2015; 20:684-96. [PMID: 25535034 DOI: 10.2119/molmed.2014.00133] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 12/12/2014] [Indexed: 01/18/2023] Open
Abstract
Glycine N-methyltransferase (GNMT) is known for its function as a tumor suppressor gene. Since 100% of female Gnmt(-/-) mice developed hepatocellular carcinoma, we hypothesized that Gnmt(-/-) mice may have defective immune surveillance. In this study, we examined the immune modulation of GNMT in T-cell responses using experimental autoimmune encephalomyelitis (EAE). The results showed that EAE severity was reduced significantly in Gnmt(-/-) mice. Pathological examination of the spinal cords revealed that Gnmt(-/-) mice had significantly lower levels of mononuclear cell infiltration and demyelination than the wild-type mice. In addition, quantitative real-time PCR showed that expression levels of proinflammatory cytokines, including interferon (IFN)-γ and interleukin (IL)-17A, were much lower in the spinal cord of Gnmt(-/-) than in that of wild-type mice. Accordingly, myelin oligodendrocyte glycoprotein (MOG)-specific T-cell proliferation and induction of T-helper (Th)1 and Th17 cells were markedly suppressed in MOG(35-55)-induced Gnmt(-/-) mice. Moreover, the number of regulatory T (Treg) cells was increased significantly in these mice. When the T-cell receptor was stimulated, the proliferative capacity and the activation status of mTOR-associated downstream signaling were decreased significantly in Gnmt(-/-) CD4(+) T cells via an IL-2- and CD25-independent manner. Moreover, GNMT deficiency enhanced the differentiation of Treg cells without affecting the differentiation of Th1 and Th17 cells. Furthermore, the severity of EAE in mice adoptive transferred with GNMT-deficient CD4(+) T cells was much milder than in those with wild-type CD4(+) T cells. In summary, our findings suggest that GNMT is involved in the pathogenesis of EAE and plays a crucial role in the regulation of CD4(+) T-cell functions.
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Affiliation(s)
- Chung-Hsien Li
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan.,Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Ming-Hong Lin
- Department and Graduate Institute of Microbiology and Immunology, National Defense Medical Center, Taipei, Taiwan
| | - Shih-Han Chu
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan.,Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Pang-Hsien Tu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Cheng-Chieh Fang
- Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan.,Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Chia-Hung Yen
- Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan.,Graduate Institute of Natural Products, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Peir-In Liang
- Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jason C Huang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yu-Chia Su
- National Laboratory Animal Center, National Applied Research Laboratories
| | - Huey-Kang Sytwu
- Department and Graduate Institute of Microbiology and Immunology, National Defense Medical Center, Taipei, Taiwan
| | - Yi-Ming Arthur Chen
- Department of Microbiology and Immunology, Institute of Medical Research and Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.,Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan.,Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
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22
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Chen M, Huang YL, Huang YC, Shui IM, Giovannucci E, Chen YC, Chen YMA. Genetic polymorphisms of the glycine N-methyltransferase and prostate cancer risk in the health professionals follow-up study. PLoS One 2014; 9:e94683. [PMID: 24800880 PMCID: PMC4011739 DOI: 10.1371/journal.pone.0094683] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Accepted: 03/18/2014] [Indexed: 11/18/2022] Open
Abstract
PURPOSE Glycine N-methyltransferase (GNMT) affects genetic stability by regulating the ratio of S-adenosylmethionine to S-adenosylhomocysteine, by binding to folate, and by interacting with environmental carcinogens. In Taiwanese men, GNMT was found to be a tumor susceptibility gene for prostate cancer. However, the association of GNMT with prostate cancer risk in other ethnicities has not been studied. It was recently reported that sarcosine, which is regulated by GNMT, increased markedly in metastatic prostate cancer. We hereby explored the association of GNMT polymorphisms with prostate cancer risk in individuals of European descent from the Health Professionals Follow-up Study (HPFS). METHODS A total of 661 incident prostate cancer cases and 656 controls were identified from HPFS. The GNMT short tandem repeat polymorphism 1 (STRP1), 4-bp insertion/deletion polymorphisms (INS/DEL) and the single nucleotide polymorphism rs10948059 were genotyped to test for their association with prostate cancer risk. RESULTS The rs10948059 T/T genotype was associated with a 1.62-fold increase in prostate cancer risk (95% confidence interval (CI): 1.18, 2.22) when compared with the C/C genotype. The STRP1 ≥ 16GAs/≥ 16GAs genotype was associated with decreased risk of prostate cancer when compared with the < 16GAs/< 16GAs genotype (odds ratio (OR) = 0.68; 95% CI: 0.46, 1.01). INS/DEL was not associated with prostate cancer risk. Haplotypes containing the rs10948059 T allele were significantly associated with increased prostate cancer risk. CONCLUSION In men of European descent, the GNMT rs10948059 and STRP1 were associated with prostate cancer risk. Compared to the study conducted in Taiwanese men, the susceptibility GNMT alleles for prostate cancer had a reverse relationship. This study highlights the differences in allelic frequencies and prostate cancer susceptibility in different ethnicities.
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Affiliation(s)
- Marcelo Chen
- Department of Urology, Mackay Memorial Hospital, Taipei, Taiwan
- Department of Cosmetic Applications and Management, Mackay Junior College of Medicine, Nursing and Management, Taipei, Taiwan
- School of Medicine, Mackay Medical College, New Taipei City, Taiwan
| | - Yi-Ling Huang
- Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Yu-Chuen Huang
- Genetics Center, Department of Medical Research, China Medical University Hospital, Taichung, Taiwan
- School of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - Irene M. Shui
- Department of Epidemiology, School of Public Health, Harvard University, Boston, Massachusetts, United States of America
| | - Edward Giovannucci
- Department of Epidemiology, School of Public Health, Harvard University, Boston, Massachusetts, United States of America
- Department of Nutrition, School of Public Health, Harvard University, Boston, Massachusetts, United States of America
| | - Yen-Ching Chen
- Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan
- Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
- Research Center for Genes, Environment, and Human Health, College of Public Health, National Taiwan University, Taipei, Taiwan
- * E-mail: (YCC); (YMC)
| | - Yi-Ming Arthur Chen
- Department of Microbiology, School of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Center for Infectious Disease and Cancer Research, Kaohsiung Medical University, Kaohsiung, Taiwan
- * E-mail: (YCC); (YMC)
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23
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Chou WY, Zhao JF, Chen YMA, Lee KI, Su KH, Shyue SK, Lee TS. Role of glycine N-methyltransferase in experimental ulcerative colitis. J Gastroenterol Hepatol 2014; 29:494-501. [PMID: 24219143 DOI: 10.1111/jgh.12434] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/18/2013] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIM Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders with unclear etiology and mechanism(s). Glycine N-methyltransferase (GNMT) plays a central role in inflammatory diseases such as hepatitis and atherosclerosis. However, little is known about the impact of GNMT and the involved mechanism in the pathogenesis of IBD. In the current study, we investigated the role of GNMT in the mouse model of dextran sulfate sodium (DSS)-induced colitis. METHODS Protein expression was determined by Western blotting or immunohistochemistry. Histopathology was examined by hematoxylin and eosin staining. Levels of pro-inflammatory cytokines were evaluated by ELISA kits. RESULTS GNMT was expressed in the epithelium of the colon under normal conditions, and with DSS treatment, its expression was predominant in infiltrated leukocytes of lesions. Mice with genetic deletion of GNMT (GNMT(-/-) ) showed increased susceptibility to DSS induction of colitis, as revealed by the progression of colitis. Additionally, severe colonic inflammation, including increased crypt loss, leukocyte infiltration, and hemorrhage, was greater with DSS treatment in GNMT(-/-) than wild-type mice. Furthermore, the expression of adhesion molecule and inflammatory mediators in the colon was significantly higher with DSS treatment in GNMT(-/-) than wild-type mice. Moreover, loss of GNMT decreased cell apoptosis in colitis lesions with DSS treatment. CONCLUSIONS Collectively, our findings suggest that GNMT may be a crucial molecule in the pathogenesis of DSS-induced colitis. This finding may provide new information for a potential therapeutic target in treating IBD.
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Affiliation(s)
- Wen-Yueh Chou
- Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
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24
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Wang YC, Lin WL, Lin YJ, Tang FY, Chen YM, Chiang EPI. A novel role of the tumor suppressor GNMT in cellular defense against DNA damage. Int J Cancer 2013; 134:799-810. [PMID: 23922098 DOI: 10.1002/ijc.28420] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 07/22/2013] [Indexed: 12/28/2022]
Abstract
Glycine N-methyltransferase (GNMT) is a folate binding protein commonly diminished in human hepatoma yet its role in tumor development remains to be established. GNMT binds to methylfolate but is also inhibited by it; how such interactions affect human carcinogenesis is unclear. We postulated that GNMT plays a role in folate-dependent methyl group homeostasis and helps maintain genome integrity by promoting nucleotide biosynthesis and DNA repair. To test the hypothesis, GNMT was over-expressed in GNMT-null cell lines cultured in conditions of folate abundance or restriction. The partitioning of folate dependent 1-carbon groups was investigated using stable isotopic tracers and GC/MS. DNA damage was assessed as uracil content in cell models, as well as in Gnmt wildtype (Gnmt(+/+)), heterozygote (Gnmt(+/-)) and knockout (Gnmt(-/-)) mice under folate deplete, replete, or supplementation conditions. Our study demonstrated that GMMT 1) supports methylene-folate dependent pyrimidine synthesis; 2) supports formylfolate dependent purine syntheses; 3) minimizes uracil incorporation into DNA when cells and animals were exposed to folate depletion; 4) translocates into nuclei during prolonged folate depletion. In conclusion, loss of GNMT impairs nucleotide biosynthesis. Over-expression of GNMT enhances nucleotide biosynthesis and improves DNA integrity by reducing uracil misincorporation in DNA both in vitro and in vivo. To our best knowledge, the role of GNMT in folate dependent 1-carbon transfer in nucleotide biosynthesis has never been investigated. The present study gives new insights into the underlying mechanism by which GNMT can participate in tumor prevention/suppression in humans.
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Affiliation(s)
- Yi-Cheng Wang
- Department of Food Science and Biotechnology, National Chung Hsing University, Taichung, Taiwan, Republic of China
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DebRoy S, Kramarenko II, Ghose S, Oleinik NV, Krupenko SA, Krupenko NI. A novel tumor suppressor function of glycine N-methyltransferase is independent of its catalytic activity but requires nuclear localization. PLoS One 2013; 8:e70062. [PMID: 23936142 PMCID: PMC3728347 DOI: 10.1371/journal.pone.0070062] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 06/18/2013] [Indexed: 01/22/2023] Open
Abstract
Glycine N-methyltransferase (GNMT), an abundant cytosolic enzyme, catalyzes the transfer of a methyl group from S-adenosylmethionine (SAM) to glycine generating S-adenosylhomocysteine and sarcosine (N-methylglycine). This reaction is regulated by 5-methyltetrahydrofolate, which inhibits the enzyme catalysis. In the present study, we observed that GNMT is strongly down regulated in human cancers and is undetectable in cancer cell lines while the transient expression of the protein in cancer cells induces apoptosis and results in the activation of ERK1/2 as an early pro-survival response. The antiproliferative effect of GNMT can be partially reversed by treatment with the pan-caspase inhibitor zVAD-fmk but not by supplementation with high folate or SAM. GNMT exerts the suppressor effect primarily in cells originated from malignant tumors: transformed cell line of non-cancer origin, HEK293, was insensitive to GNMT. Of note, high levels of GNMT, detected in regenerating liver and in NIH3T3 mouse fibroblasts, do not produce cytotoxic effects. Importantly, GNMT, a predominantly cytoplasmic protein, was translocated into nuclei upon transfection of cancer cells. The presence of GNMT in the nuclei was also observed in normal human tissues by immunohistochemical staining. We further demonstrated that the induction of apoptosis is associated with the GNMT nuclear localization but is independent of its catalytic activity or folate binding. GNMT targeted to nuclei, through the fusion with nuclear localization signal, still exerts strong antiproliferative effects while its restriction to cytoplasm, through the fusion with nuclear export signal, prevents these effects (in each case the protein was excluded from cytosol or nuclei, respectively). Overall, our study indicates that GNMT has a secondary function, as a regulator of cellular proliferation, which is independent of its catalytic role.
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Affiliation(s)
- Suchandra DebRoy
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Inga I. Kramarenko
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Sampa Ghose
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Natalia V. Oleinik
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Sergey A. Krupenko
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Natalia I. Krupenko
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail:
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Huidobro C, Fernandez AF, Fraga MF. The role of genetics in the establishment and maintenance of the epigenome. Cell Mol Life Sci 2013; 70:1543-73. [PMID: 23474979 PMCID: PMC11113764 DOI: 10.1007/s00018-013-1296-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 02/05/2013] [Accepted: 02/05/2013] [Indexed: 12/19/2022]
Abstract
Epigenetic mechanisms play an important role in gene regulation during development. DNA methylation, which is probably the most important and best-studied epigenetic mechanism, can be abnormally regulated in common pathologies, but the origin of altered DNA methylation remains unknown. Recent research suggests that these epigenetic alterations could depend, at least in part, on genetic mutations or polymorphisms in DNA methyltransferases and certain genes encoding enzymes of the one-carbon metabolism pathway. Indeed, the de novo methyltransferase 3B (DNMT3B) has been recently found to be mutated in several types of cancer and in the immunodeficiency, centromeric region instability and facial anomalies syndrome (ICF), in which these mutations could be related to the loss of global DNA methylation. In addition, mutations in glycine-N-methyltransferase (GNMT) could be associated with a higher risk of hepatocellular carcinoma and liver disease due to an unbalanced S-adenosylmethionine (SAM)/S-adenosylhomocysteine (SAH) ratio, which leads to aberrant methylation reactions. Also, genetic variants of chromatin remodeling proteins and histone tail modifiers are involved in genetic disorders like α thalassemia X-linked mental retardation syndrome, CHARGE syndrome, Cockayne syndrome, Rett syndrome, systemic lupus erythematous, Rubinstein-Taybi syndrome, Coffin-Lowry syndrome, Sotos syndrome, and facioescapulohumeral syndrome, among others. Here, we review the potential genetic alterations with a possible role on epigenetic factors and discuss their contribution to human disease.
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Affiliation(s)
- Covadonga Huidobro
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA-HUCA), University of Oviedo, Oviedo, Spain
| | - Agustin F. Fernandez
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA-HUCA), University of Oviedo, Oviedo, Spain
| | - Mario F. Fraga
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA-HUCA), University of Oviedo, Oviedo, Spain
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
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Excision repair of BPDE-adducts in human lymphocytes: diminished capacity associated with ERCC1 C8092A (rs3212986) polymorphism. Arch Toxicol 2012. [PMID: 23203453 DOI: 10.1007/s00204-012-0986-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), a metabolite of Benzo[a]pyrene (B[a]P), is a high-risk factor for development of a number of cancers. DNA damage caused by BPDE is normally repaired by Nucleotide Excision Repair system of which ERCC1 exerts an important role. We investigated whether two single nucleotide polymorphisms in ERCC1 (C19007T; rs11615 and C8092A; rs3213986) affected the repair efficacy of BPDE-DNA adducts. We collected peripheral blood of 780 healthy individuals from the northeast of China and detected the genotypes of rs11615 and rs3213986. The amount of induced BPDE-DNA adducts in lymphocytes from 117 randomly selected participants was assessed by HPLC. Presence of BPDE-DNA adducts in nucleus of lymphocytes was visualized using the modified comet assay. ERCC1 and CAST (3' adjacent gene of ERCC1) mRNA expression levels were quantified after in vitro exposure to BPDE. We found that the minor A allele in rs3212986 was related to higher levels of BPDE-DNA adducts and holistic marking DNA damage (P < 0.01). Haplotype CA (rs11615 and rs3213986) was also associated with an elevated risk of high BPDE-DNA adduct levels (OR = 1.801, 95 % CI of OR 1.191-2.724). Interestingly, in participants with AA genotype for rs3213986, CAST mRNA level was decreased compared to individuals with the homozygous CC genotype. Our findings suggests that ERCC1 C8092A (rs3213986) is associated with a diminished capacity of repairing BPDE-DNA adducts and may be used as a valid biomarker to predict an individual's risk to develop cancer upon exposure to environmental carcinogens.
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The multi-functional roles of GNMT in toxicology and cancer. Toxicol Appl Pharmacol 2012; 266:67-75. [PMID: 23147572 DOI: 10.1016/j.taap.2012.11.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Revised: 11/02/2012] [Accepted: 11/03/2012] [Indexed: 11/23/2022]
Abstract
Although glycine N-methyltransferase (GNMT) has been discovered for five decades, its function was not elucidated until recently. In this review, we discuss the multiple roles of GNMT in toxicology and cancer. Besides catalyzing the production of methylglycine (sarcosine) in one carbon metabolism pathway, GNMT was found to be able to bind a number of polycyclic aromatic hydrocarbons and inhibit DNA adducts formation. Moreover, GNMT exerts protective effects against the cytotoxicity and carcinogenicity of benzo(a)pyrene and aflatoxin B(1) in vitro and in vivo. Occupational study showed that workers who had genotypes with higher GNMT promoter activity may have lower content of oxidative damaged DNA products in their urine. In terms of cancer, recent studies using GNMT knockout mouse models demonstrated that GNMT deficiency has high penetrance in inducing the development of steatohepatitis and hepatocellular carcinoma. In terms of the mechanism, besides dysregulation of epigenetic modification, insights have been provided by recent identification of two novel proteins interacting with GNMT-DEPTOR and NPC2. These studies suggest that GNMT not only is involved in mTOR signaling pathway, but also plays an important role in the intracellular trafficking of cholesterol. The implication of these findings to the preventive medicine and translational research will be discussed.
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Chen CY, Ching LC, Liao YJ, Yu YB, Tsou CY, Shyue SK, Chen YMA, Lee TS. Deficiency of glycine N-methyltransferase aggravates atherosclerosis in apolipoprotein E-null mice. Mol Med 2012; 18:744-52. [PMID: 22415010 DOI: 10.2119/molmed.2011.00396] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 03/07/2012] [Indexed: 12/22/2022] Open
Abstract
The mechanism underlying the dysregulation of cholesterol metabolism and inflammation in atherogenesis is not understood fully. Glycine N-methyltransferase (GNMT) has been implicated in hepatic lipid metabolism and the pathogenesis of liver diseases. However, little is known about the significance of GNMT in atherosclerosis. We showed the predominant expression of GNMT in foamy macrophages of mouse atherosclerotic aortas. Genetic deletion of GNMT exacerbated the hyperlipidemia, inflammation and development of atherosclerosis in apolipoprotein E-deficient mice. In addition, ablation of GNMT in macrophages aggravated oxidized low-density lipoprotein-mediated cholesterol accumulation in macrophage foam cells by downregulating the expression of reverse cholesterol transporters including ATP-binding cassette transporters-A1 and G1 and scavenger receptor BI. Furthermore, tumor necrosis factor-α-induced inflammatory response was promoted in GNMT-null macrophages. Collectively, our data suggest that GNMT is a crucial regulator in cholesterol metabolism and in inflammation, and contributes to the pathogenesis of atherosclerosis. This finding may reveal a potential therapeutic target for atherosclerosis.
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Affiliation(s)
- Chien-Yu Chen
- Department of Physiology, School of Medicine, National Yang-Ming University, Taipei, Taiwan
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30
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Liao YJ, Chen TL, Lee TS, Wang HA, Wang CK, Liao LY, Liu RS, Huang SF, Chen YMA. Glycine N-methyltransferase deficiency affects Niemann-Pick type C2 protein stability and regulates hepatic cholesterol homeostasis. Mol Med 2012; 18:412-22. [PMID: 22183894 DOI: 10.2119/molmed.2011.00258] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 12/14/2011] [Indexed: 01/09/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is associated with the development of metabolic syndromes and hepatocellular carcinoma (HCC). Cholesterol accumulation is related to NAFLD, whereas its detailed mechanism is not fully understood. Previously, we reported that glycine N-methyltransferase (GNMT) knockout (Gnmt(-/-)) mice develop chronic hepatitis and HCC. In this study, we showed that Gnmt(-/-) mice had hyperlipidemia and steatohepatitis. Single photon emission computed tomography images of mice injected with (131)I-labeled 6β-iodocholesterol demonstrated that Gnmt(-/-) mice had slower hepatic cholesterol uptake and excretion rates than wild-type mice. In addition, genes related to cholesterol uptake (scavenger receptor class B type 1 [SR-B1] and ATP-binding cassette A1 [ABCA1]), intracellular trafficking (Niemann-Pick type C1 protein [NPC1] and Niemann-Pick type C2 protein [NPC2]) and excretion (ATP-binding cassette G1 [ABCG1]) were downregulated in Gnmt(-/-) mice. Yeast two-hybrid screenings and coimmunoprecipitation assays elucidated that the C conserved region (81-105 amino acids) of NPC2 interacts with the carboxyl-terminal fragment (171-295 amino acids) of GNMT. Confocal microscopy demonstrated that when cells were treated with low-density lipoprotein, NPC2 was released from lysosomes and interacts with GNMT in the cytosol. Overexpression of GNMT doubled the half-lives of both NPC2 isoforms and reduced cholesterol accumulation in cells. Furthermore, GNMT was downregulated in the liver tissues from patients suffering with NAFLD as well as from mice fed a high-fat diet, high-cholesterol diet or methionine/choline-deficient diet. In conclusion, our study demonstrated that GNMT regulates the homeostasis of cholesterol metabolism, and hepatic cholesterol accumulation may result from downregulation of GNMT and instability of its interactive protein NPC2. Novel therapeutics for steatohepatitis and HCC may be developed by using this concept.
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Affiliation(s)
- Yi-Jen Liao
- AIDS Prevention and Research Center, National Yang-Ming University, Taipei, Taiwan
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31
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Yen CH, Lu YC, Li CH, Lee CM, Chen CY, Cheng MY, Huang SF, Chen KF, Cheng AL, Liao LY, Lee YHW, Chen YMA. Functional characterization of glycine N-methyltransferase and its interactive protein DEPDC6/DEPTOR in hepatocellular carcinoma. Mol Med 2012; 18:286-96. [PMID: 22160218 DOI: 10.2119/molmed.2011.00331] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 11/29/2011] [Indexed: 12/21/2022] Open
Abstract
Glycine N-methyltransferase (GNMT) is a tumor suppressor for hepatocellular carcinoma (HCC). High rates of Gnmt knockout mice developed HCC. Epigenetic alteration and dysregulation of several pathways including wingless-type MMTV integration site (Wnt), mitogen-activated protein kinase (MAPK) and Janus kinase and signal transducer and activator of transcription (JAK-STAT) are associated with HCC development in Gnmt knockout mice. We hypothesized that GNMT may regulate signal transduction through interacting with other proteins directly. In this report, we identified a mammalian target of rapamycin (mTOR) inhibitor (DEP domain containing MTOR-interacting protein [DEPDC6/DEPTOR]) as a GNMT-binding protein by using yeast two-hybrid screening. Fluorescence resonance energy transfer assay demonstrated that the C-terminal half of GNMT interact with the PSD-95/Dlg1/ZO-1 (PDZ) domain of DEPDC6/DEPTOR. Immunohistochemical staining showed that 27.5% (14/51) of HCC patients had higher expression levels of DEPDC6/DEPTOR in the tumorous tissues than in tumor-adjacent tissues, especially among HCC patients with hepatitis B viral infection (odds ratio 10.3, 95% confidence interval [CI] 1.05-11.3) or patients with poor prognosis (death hazard ratio 4.51, 95% CI 1.60-12.7). In terms of molecular mechanism, knockdown of DEPDC6/DEPTOR expression in HuH-7 cells caused S6K and 4E-BP activation, but suppressed Akt. Overexpression of DEPDC6/DEPTOR activated Akt and increased survival of HCC cells. Overexpression of GNMT caused activation of mTOR/raptor downstream signaling and delayed G2/M cell cycle progression, which altogether resulted in cellular senescence. Furthermore, GNMT reduced proliferation of HuH-7 cells and sensitized them to rapamycin treatment both in vitro and in vivo. In conclusion, GNMT regulates HCC growth in part through interacting with DEPDC6/DEPTOR and modulating mTOR/raptor signaling pathway. Both GNMT and DEPDC6/DEPTOR are potential targets for developing therapeutics for HCC.
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Affiliation(s)
- Chia-Hung Yen
- AIDS Prevention and Research Center, National Yang-Ming University, Shih-Pai, Taipei, Taiwan
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Glycine N-Methyltransferase Affects Urinary 1-Hydroxypyrene and 8-Hydroxy-2′-Deoxyguanosine Levels After PAH Exposure. J Occup Environ Med 2011; 53:812-9. [DOI: 10.1097/jom.0b013e318222b79a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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33
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Wang YC, Tang FY, Chen SY, Chen YM, Chiang EPI. Glycine-N methyltransferase expression in HepG2 cells is involved in methyl group homeostasis by regulating transmethylation kinetics and DNA methylation. J Nutr 2011; 141:777-82. [PMID: 21411609 DOI: 10.3945/jn.110.135954] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Glycine-N methyltransferase (GNMT) is a potential tumor suppressor that is commonly inactivated in human hepatoma. We systematically investigated how GNMT regulates methyl group kinetics and global DNA methylation. HepG2 cells (GNMT inactive, GNMT-) and cells transfected with GNMT expressed vector (GNMT+) were cultured in low (10 μmol/L), adequate (100 μmol/L), or high (500 μmol/L) l-methionine, each with 2.27 μmol/L folate. Transmethylation kinetics were studied using stable isotopic tracers and GC-MS. Methylation status was determined by S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) levels, SAM:SAH ratio, DNA methyltransferase (DNMT) activity, and methylated cytidine levels in DNA. Compared with GNMT- cells, GNMT+ cells had lower homocysteine and greater cysteine concentrations. GNMT expression increased methionine clearance by inducing homocysteine transsulfuration and remethylation metabolic fluxes when cells were cultured in high or adequate l-methionine. In contrast, homocysteine remethylation flux was lower in GNMT+ cells than in GNMT- cells and homocysteine transsulfuration fluxes did not differ when cells were cultured in low methionine, suggesting that normal GNMT function helps to conserve methyl groups. Furthermore, GNMT expression decreased SAM and increased SAH levels and reduced DNMT activity in high or adequate, but not low, methionine cultures. In low methionine cultures, restoring GNMT in HepG2 cells did not lead to sarcosine synthesis, which would waste methyl groups. Methylated cytidine levels were significantly lower in GNMT- cells than in GNMT+ cells. In conclusion, we have shown that GNMT affects transmethylation kinetics and SAM synthesis and facilitates the conservation of methyl groups by limiting homocysteine remethylation fluxes.
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Affiliation(s)
- Yi-Cheng Wang
- Department of Food Science and Biotechnology, National Chung Hsing University, Taichung, Taiwan
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34
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Leclerc J, Courcot-Ngoubo Ngangue E, Cauffiez C, Allorge D, Pottier N, Lafitte JJ, Debaert M, Jaillard S, Broly F, Lo-Guidice JM. Xenobiotic metabolism and disposition in human lung: transcript profiling in non-tumoral and tumoral tissues. Biochimie 2011; 93:1012-27. [PMID: 21376776 DOI: 10.1016/j.biochi.2011.02.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 02/22/2011] [Indexed: 11/30/2022]
Abstract
The lung is directly exposed to a wide variety of inhaled toxicants and carcinogens. In order to improve our knowledge of the cellular processing of these compounds in the respiratory tract, we investigated the mRNA expression level of 380 genes encoding xenobiotic-metabolizing enzymes (XME), transporters, nuclear receptors and transcription factors, in pulmonary parenchyma (PP), bronchial mucosa (BM) and tumoral lung tissues from 12 patients with non-small cell lung cancer (NSCLC). Using a high throughput quantitative real-time RT-PCR method, we found that ADH1B, CYP4B1, CES1 and GSTP1 are the major XME genes expressed both in BM and PP. Our results also documented the predominant role played by the xenosensor AhR in human lung. The gene expression profiles were different for BM and PP, with a tendency toward increased mRNA levels of phase I and phase II XME genes in BM, suggesting major differences in the initial stages of xenobiotic metabolism. Some of the significantly overexpressed genes in BM (i.e. CYP2F1, CYP2A13, CYP2W1, NQO1…) encode proteins involved in the bioactivation of procarcinogens, pointing out distinct susceptibility to xenobiotics and their toxic effects between these two tissue types. Additionally, interindividual differences in transcript levels observed for some genes may be of genetic origin and may contribute to the variability in response to environmental exposure and, consequently, in the risk of developing lung diseases. A global decrease in gene expression was observed in tumoral specimens. Some of the proteins are involved in the metabolism or transport of anti-cancer drugs and their influence in the response of tumors to chemotherapy should be considered. In conclusion, the present study provides an overview of the cellular response to toxicants and drugs in healthy and cancerous human lung tissues, and thus improves our understanding of the mechanisms of chemical carcinogenesis as well as cellular resistance to chemotherapy.
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Affiliation(s)
- Julie Leclerc
- Equipe d'accueil EA4483, Faculté de Médecine Pôle Recherche, Université Lille Nord de France, 1 Place de Verdun, 59045 Lille, France.
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35
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Barr J, Vázquez-Chantada M, Alonso C, Pérez-Cormenzana M, Mayo R, Galán A, Caballería J, Martín-Duce A, Tran A, Wagner C, Luka Z, Lu SC, Castro A, Le Marchand-Brustel Y, Martínez-Chantar ML, Veyrie N, Clément K, Tordjman J, Gual P, Mato JM. Liquid chromatography-mass spectrometry-based parallel metabolic profiling of human and mouse model serum reveals putative biomarkers associated with the progression of nonalcoholic fatty liver disease. J Proteome Res 2011; 9:4501-12. [PMID: 20684516 DOI: 10.1021/pr1002593] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease in most western countries. Current NAFLD diagnosis methods (e.g., liver biopsy analysis or imaging techniques) are poorly suited as tests for such a prevalent condition, from both a clinical and financial point of view. The present work aims to demonstrate the potential utility of serum metabolic profiling in defining phenotypic biomarkers that could be useful in NAFLD management. A parallel animal model/human NAFLD exploratory metabolomics approach was employed, using ultra performance liquid chromatography-mass spectrometry (UPLC-MS) to analyze 42 serum samples collected from nondiabetic, morbidly obese, biopsy-proven NAFLD patients, and 17 animals belonging to the glycine N-methyltransferase knockout (GNMT-KO) NAFLD mouse model. Multivariate statistical analysis of the data revealed a series of common biomarkers that were significantly altered in the NAFLD (GNMT-KO) subjects in comparison to their normal liver counterparts (WT). Many of the compounds observed could be associated with biochemical perturbations associated with liver dysfunction (e.g., reduced Creatine) and inflammation (e.g., eicosanoid signaling). This differential metabolic phenotyping approach may have a future role as a supplement for clinical decision making in NAFLD and in the adaption to more individualized treatment protocols.
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Affiliation(s)
- Jonathan Barr
- OWL Genomics, Bizkaia Technology Park, 48160-Derio, Bizkaia, Spain
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Wang YC, Chen YM, Lin YJ, Liu SP, Chiang EPI. GNMT expression increases hepatic folate contents and folate-dependent methionine synthase-mediated homocysteine remethylation. Mol Med 2011; 17:486-94. [PMID: 21210071 DOI: 10.2119/molmed.2010.00243] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 12/30/2010] [Indexed: 11/06/2022] Open
Abstract
Glycine N-methyltransferase (GNMT) is a major hepatic enzyme that converts S-adenosylmethionine to S-adenosylhomocysteine while generating sarcosine from glycine, hence it can regulate mediating methyl group availability in mammalian cells. GNMT is also a major hepatic folate binding protein that binds to, and, subsequently, may be inhibited by 5-methyltetrafolate. GNMT is commonly diminished in human hepatoma; yet its role in cellular folate metabolism, in tumorigenesis and antifolate therapies, is not understood completely. In the present study, we investigated the impacts of GNMT expression on cell growth, folate status, methylfolate-dependent reactions and antifolate cytotoxicity. GNMT-diminished hepatoma cell lines transfected with GNMT were cultured under folate abundance or restriction. Folate-dependent homocysteine remethylation fluxes were investigated using stable isotopic tracers and gas chromatography/mass spectrometry. Folate status was compared between wild-type (WT), GNMT transgenic (GNMT(tg)) and GNMT knockout (GNMT(ko)) mice. In the cell model, GNMT expression increased folate concentration, induced folate-dependent homocysteine remethylation, and reduced antifolate methotrexate cytotoxicity. In the mouse models, GNMT(tg) had increased hepatic folate significantly, whereas GNMT(ko) had reduced folate. Liver folate levels correlated well with GNMT expressions (r = 0.53, P = 0.002); and methionine synthase expression was reduced significantly in GNMT(ko), demonstrating impaired methylfolate-dependent metabolism by GNMT deletion. In conclusion, we demonstrated novel findings that restoring GNMT assists methylfolate-dependent reactions and ameliorates the consequences of folate depletion. GNMT expression in vivo improves folate retention and bioavailability in the liver. Studies on how GNMT expression impacts the distribution of different folate cofactors and the regulation of specific folate dependent reactions are underway.
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Affiliation(s)
- Yi-Cheng Wang
- Department of Food Science and Biotechnology, National Chung Hsing University, Taichung, Taiwan, R.O.C
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37
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Wang Y, Yang B, Wu C, Zheng Z, Yuan Y, Hu Z, Ma H, Li S, Liao M, Wang Q. Plasma and liver proteomic analysis of 3Z-3-[(1H-pyrrol-2-yl)-methylidene]-1-(1-piperidinylmethyl)-1,3-2H-indol-2-one-induced hepatotoxicity in Wistar rats. Proteomics 2010; 10:2927-41. [PMID: 20544730 DOI: 10.1002/pmic.200900699] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
3Z-3-[(1H-pyrrol-2-yl)-methylidene]-1-(1-piperidinylmethyl)-1,3-2H-indol-2-one (Z24), a synthetic anti-angiogenic compound, inhibits the growth and metastasis of certain tumors. Previous works have shown that Z24 induces hepatotoxicity in rodents. We examined the hepatotoxic mechanism of Z24 at the protein level and looked for potential biomarkers. We used 2-DE and MALDI-TOF/TOF MS to analyze alternatively expressed proteins in rat liver and plasma after Z24 administration. We also examined apoptosis in rat liver and measured levels of intramitochondrial ROS and NAD(P)H redox in liver cells. We found that 22 nonredundant proteins in the liver and 11 in the plasma were differentially expressed. These proteins were involved in several important metabolic pathways, including carbohydrate, lipid, amino acid, and energy metabolism, biotransformation, apoptosis, etc. Apoptosis in rat liver was confirmed with the terminal deoxynucleotidyl transferase dUTP-nick end labeling assay. In mitochondria, Z24 increased the ROS and decreased the NAD(P)H levels. Thus, inhibition of carbohydrate aerobic oxidation, fatty acid beta-oxidation, and oxidative phosphorylation is a potential mechanism of Z24-induced hepatotoxicity, resulting in mitochondrial dysfunction and apoptosis-mediated cell death. In addition, fetub protein and argininosuccinate synthase in plasma may be potential biomarkers of Z24-induced hepatotoxicity.
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Affiliation(s)
- Ying Wang
- Beijing Institute of Pharmacology and Toxicology, Beijing, P R China
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Tsai MJ, Chen YMA, Weng CF, Liou DY, Yang HC, Chen CH, Liao RIH, Kuo FS, Chiu CW, Kuo HS, Huang MC, Lin YL, Lee MJ, Kuo WC, Huang WC, Cheng H. Enhanced expression of glycine N-methyltransferase by adenovirus-mediated gene transfer in CNS culture is neuroprotective. Ann N Y Acad Sci 2010; 1199:194-203. [PMID: 20633125 DOI: 10.1111/j.1749-6632.2009.05169.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Glycine N-methyltransferase (GNMT) is the most abundant hepatic methyltransferase and plays important roles in regulating methyl group metabolism. In the central nervous system, GNMT expression is low and its function has not been revealed. The present study examines the effect of GNMT overexpression by adenovirus-mediated transfer in cortical mixed neuron-glial cultures. Infection of adenovirus encoding green fluorescence protein to cultures demonstrates high preference for non-neuronal cells. Optimal GNMT overexpression in cultures by adenoviral GNMT (Ad-GNMT) infection not only induces protein kinase C phosphorylation, but also increases neuronal/oligodendroglial survival. Furthermore, these Ad-GNMT-infected cultures are significantly resistant to H(2)O(2) toxicity and lipopolysaccharide stimulation. Conditioned media from Ad-GNMT-infected microglia also significantly enhance neuronal survival. Taken together, enhanced GNMT expression in mixed neuronal-glial cultures is neuroprotective, most likely mediated through non-neuronal cells.
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Affiliation(s)
- May-Jywan Tsai
- Neural Regeneration Laboratory, Department of Neurosurgery, Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
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Fang X, Dong W, Thornton C, Willett KL. Benzo[a]pyrene effects on glycine N-methyltransferase mRNA expression and enzyme activity in Fundulus heteroclitus embryos. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 98:130-138. [PMID: 20185185 PMCID: PMC2873104 DOI: 10.1016/j.aquatox.2010.02.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 01/28/2010] [Accepted: 02/01/2010] [Indexed: 05/28/2023]
Abstract
Benzo[a]pyrene (BaP) is a ubiquitous environmental polycyclic aromatic hydrocarbon (PAH) contaminant that is both a carcinogen and a developmental toxicant. We hypothesize that some of BaP's developmental toxicity may be mediated by effects on glycine N-methyltransferase (GNMT). GNMT is a mediator in the methionine and folate cycles, and the homotetrameric form enzymatically transfers a methyl group from S-adenosylmethionine (SAM) to glycine forming S-adenosylhomocysteine (SAH) and sarcosine. SAM homeostasis, as regulated by GNMT, is critically involved in regulation of DNA methylation, and altered GNMT expression is associated with liver pathologies. The homodimeric form of GNMT has been suggested as the 4S PAH-binding protein. To further study BaP-GNMT interactions, Fundulus heteroclitus embryos were exposed to waterborne BaP at 10 and 100mug/L and both GNMT mRNA expression and enzyme activity were determined. Whole mount in situ hybridization showed GNMT mRNA expression was increased by BaP in the liver region of 7, 10 and 14dpf F. heteroclitus embryos. In contrast to mRNA induction, in vivo BaP exposure decreased GNMT enzyme activity in 4, 10 and 14dpf embryos. However, in vitro incubations of adult F. heteroclitus liver cytosol with BaP did not cause decreased enzyme activity. In conclusion, BaP exposure altered GNMT expression, which may represent a new target pathway for BaP-mediated embryonic toxicities and DNA methylation changes.
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Affiliation(s)
- Xiefan Fang
- Department of Pharmacology and Environmental Toxicology Research Program, School of Pharmacy, University of Mississippi, University, Mississippi, USA, 38677
| | - Wu Dong
- Department of Pharmacology and Environmental Toxicology Research Program, School of Pharmacy, University of Mississippi, University, Mississippi, USA, 38677
| | - Cammi Thornton
- Department of Pharmacology and Environmental Toxicology Research Program, School of Pharmacy, University of Mississippi, University, Mississippi, USA, 38677
| | - Kristine L. Willett
- Department of Pharmacology and Environmental Toxicology Research Program, School of Pharmacy, University of Mississippi, University, Mississippi, USA, 38677
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Liao YJ, Chen KH, Huang SF, Chen TL, Wang CK, Chien CH, Tsai TF, Liu SP, Chen YMA. Deficiency of glycine N-methyltransferase results in deterioration of cellular defense to stress in mouse liver. Proteomics Clin Appl 2010; 4:394-406. [PMID: 21137059 DOI: 10.1002/prca.200900074] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 09/14/2009] [Accepted: 10/19/2009] [Indexed: 12/23/2022]
Abstract
PURPOSE Previously, we reported that glycine N-methyltransferase (GNMT) interacts with benzo[a]pyrene (BaP) and inhibits BaP-DNA adducts formation. In addition, Gnmt knockout (Gnmt(-/-)) mice developed chronic hepatitis and hepatocellular carcinoma (HCC). The aims of this study were to understand the gene expression profile of Gnmt(-/-) mice and to study the interaction between BaP and GNMT deficiency in vivo. EXPERIMENTAL DESIGN Gene expression profiles of Gnmt(-/-) mice were analyzed by 2-D PAGE and real-time PCR. Both wild-type and Gnmt(-/-) mice were challenged with BaP and sacrificed at the age of 13 months. RESULTS Compared with the wild-type mice, proteins involved in the anti-oxidation/detoxification response, glycolytic energy metabolism and one-carbon metabolism pathways were down-regulated significantly in Gnmt(-/-) mice. Malondialdehyde assay showed that lipid peroxidation was significantly increased in the Gnmt(-/-) mice liver. H(2)O(2) treatment demonstrated that the survival rate of HuH-7 cells overexpressing GNMT was significantly higher than the controls. BaP challenge experiments showed that 71.4% (5/7) of male and all (7/7) female Gnmt(-/-) mice developed HCC, while only 16.7% (1/6) of male and 20% (1/5) of female wild-type mice had HCC. CONCLUSION AND CLINICAL RELEVANCE GNMT regulates genes related to detoxification and anti-oxidation pathways. BaP is a liver cancer carcinogen especially during GNMT deficiency.
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Affiliation(s)
- Yi-Jen Liao
- Molecular Medicine Program, Institute of Public Health, School of Medicine, National Yang-Ming University, Taipei, Taiwan
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41
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Fang X, Dong W, Thornton C, Scheffler B, Willett KL. Benzo(a)pyrene induced glycine N-methyltransferase messenger RNA expression in Fundulus heteroclitus embryos. MARINE ENVIRONMENTAL RESEARCH 2010; 69 Suppl:S74-6. [PMID: 19892394 PMCID: PMC2889013 DOI: 10.1016/j.marenvres.2009.10.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Revised: 09/17/2009] [Accepted: 10/12/2009] [Indexed: 05/07/2023]
Abstract
Glycine N-methyltransferase (GNMT) is a mediator in the methionine and folate cycles, and is responsible for the transfer of a methyl group from S-adenosylmethionine (SAM) to glycine forming S-adenosylhomocysteine (SAH) and sarcosine. All the known DNA methyltransferases use SAM as a methyl donor thus, GNMT is critically involved in regulation of DNA methylation. Altered GNMT activities have been associated with liver pathologies including hepatocellular carcinoma. The homotetramer form of GNMT is enzymatically active, but the homodimeric form has been suggested as the 4S PAH-binding protein which may mediate CYP1A expression. To further understand the role of GNMT in benzo(a)pyrene (BaP)-related toxicity, full length Fundulus heteroclitus GNMT cDNA was cloned from adult liver. The open reading frame (ORF) of GNMT is 888 base pairs long and encodes a deduced protein of 295 amino acids which has 74% identity with human GNMT. Expression of GNMT mRNA was determined by quantitative RT-PCR. In unfertilized, 2days postfertilization (dpf), and 3 dpf embryos GNMT was constitutively higher than in 4, 7, 10 or 14 dpf embryos. Embryos were also exposed to waterborne BaP at 10 and 100 μg L⁻¹, and by 10 dpf the higher BaP dose caused increased expression of GNMT mRNA. These results suggest that PAH exposure may alter expression of an important physiological methylation mediator. Future work will be necessary to determine enzyme level effects of BaP exposure as well.
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Affiliation(s)
- Xiefan Fang
- Department of Pharmacology and Environmental Toxicology Research Program, School of Pharmacy, University of Mississippi, University, MS, USA
| | - Wu Dong
- Department of Pharmacology and Environmental Toxicology Research Program, School of Pharmacy, University of Mississippi, University, MS, USA
| | - Cammi Thornton
- Department of Pharmacology and Environmental Toxicology Research Program, School of Pharmacy, University of Mississippi, University, MS, USA
| | - Brian Scheffler
- USDA-ARS Genomics and Bioinformatics Research Unit, Stoneville, MS, USA
| | - Kristine L. Willett
- Department of Pharmacology and Environmental Toxicology Research Program, School of Pharmacy, University of Mississippi, University, MS, USA
- Corresponding author Kristine L. Willett Box 1848, 200 Faser Hall Department of Pharmacology University of Mississippi University, MS 38677 Tel: (662) 915-6691 Fax: (662) 915-5148
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Lee CM, Shih YP, Wu CH, Chen YMA. Characterization of the 5' regulatory region of the human Glycine N-methyltransferase gene. Gene 2009; 443:151-7. [PMID: 19439180 DOI: 10.1016/j.gene.2009.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Revised: 04/13/2009] [Accepted: 05/04/2009] [Indexed: 10/20/2022]
Abstract
Glycine N-methyltransferase (GNMT) is a tumor susceptibility gene for both hepatocellular carcinoma and prostate cancer. We have previously characterized GNMT genomic structure and mapped its chromosomal localization to 6p12. For this study we identified a GNMT transcriptional start site at the 14th position upstream of the ATG codon. Electrophoretic mobility shift assay results indicate binding of the nuclear factor-Y (NF-Y) transcription factor to the CCAAT box (-71/-67) of the GNMT gene. Mutation assay results suggest that the nucleotide sequence in the -56/-47 region is a binding site for a putative transcriptional factor. The TATA-less core promoter (-133/+14) contains three major elements: an Sp1 site, CCAAT box, and a novel box within the CTGTCGGCTG sequence. One functional xenobiotic response element (XRE) located at the -104/-82 region is inducable by benzo[a]pyrene treatment. We believe our results have value for the study of GNMT transcriptional regulation.
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Affiliation(s)
- Cheng-Ming Lee
- AIDS Prevention and Research Center, National Yang-Ming University, Taipei 112, Taiwan
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Liao YJ, Liu SP, Lee CM, Yen CH, Chuang PC, Chen CY, Tsai TF, Huang SF, Lee YHW, Chen YMA. Characterization of a glycine N-methyltransferase gene knockout mouse model for hepatocellular carcinoma: Implications of the gender disparity in liver cancer susceptibility. Int J Cancer 2009; 124:816-26. [PMID: 19035462 DOI: 10.1002/ijc.23979] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Hepatocellular carcinoma (HCC) is the fifth common cancer in the world and it mainly occurs in men. Glycine N-methyltransferase (GNMT) participates in one-carbon metabolism and affects DNA methylation by regulating the ratio of S-adenosylmethionine to S-adenosylhomocystine. Previously, we described that the expression of GNMT was diminished in human HCC. Here, we showed that 50% (3/6) male and 100% (7/7) female Gnmt-/- mice developed HCC, and their mean ages of HCC development were 17 and 16.5 months, respectively. In addition, 42.9% (3/7) of female Gnmt-/- mice had hemangioma. Wnt reporter assay demonstrated that Gnmt is a negative regulator for canonical Wnt signaling pathway. Beta-catenin, cyclin D1 and c-Myc, genes related to Wnt pathway, were upregulated in the liver tissues from both 11 weeks and HCC stage of Gnmt-/- mice. Furthermore, global DNA hypomethylation and aberrant expression of DNA methyltransferases 1 and 3b were found in the early and late stages of HCC development. Hierarchical cluster analysis of 6,023 transcripts from microarray data found that gene expression patterns of HCC tumors from male and female Gnmt-/- mice were distinctively different. Real-time PCR confirmed that Gadd45a, Pak1, Mapk3 and Dsup3 genes of mitogen-activated protein kinase (MAPK) pathway were activated in Gnmt-/- mice, especially in the female mice. Therefore, GNMT is a tumor suppressor gene for liver cancer, and it is associated with gender disparity in liver cancer susceptibility.
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Affiliation(s)
- Yi-Jen Liao
- Molecular Medicine Program, Institute of Public Health, School of Medicine, National Yang-Ming University, Taipei, Taiwan
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Yen CH, Hung JH, Ueng YF, Liu SP, Chen SY, Liu HH, Chou TY, Tsai TF, Darbha R, Hsieh LL, Chen YMA. Glycine N-methyltransferase affects the metabolism of aflatoxin B1 and blocks its carcinogenic effect. Toxicol Appl Pharmacol 2008; 235:296-304. [PMID: 19146867 DOI: 10.1016/j.taap.2008.12.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 10/21/2008] [Accepted: 12/12/2008] [Indexed: 11/16/2022]
Abstract
Previously, we reported that glycine N-methyltransferase (GNMT) knockout mice develop chronic hepatitis and hepatocellular carcinoma (HCC) spontaneously. For this study we used a phosphoenolpyruvate carboxykinase promoter to establish a GNMT transgenic (TG) mouse model. Animals were intraperitoneally inoculated with aflatoxin B(1) (AFB(1)) and monitored for 11 months, during which neither male nor female GNMT-TG mice developed HCC. In contrast, 4 of 6 (67%) male wild-type mice developed HCC. Immunofluorescent antibody test showed that GNMT was translocated into nuclei after AFB(1) treatment. Competitive enzyme immunoassays indicated that after AFB(1) treatment, the AFB(1)-DNA adducts formed in stable clones expressing GNMT reduced 51.4% compared to the vector control clones. Experiments using recombinant adenoviruses carrying GNMT cDNA (Ad-GNMT) further demonstrated that the GNMT-related inhibition of AFB(1)-DNA adducts formation is dose-dependent. HPLC analysis of the metabolites of AFB(1) in the cultural supernatants of cells exposed to AFB(1) showed that the AFM(1) level in the GNMT group was significantly higher than the control group, indicating the presence of GNMT can enhance the detoxification pathway of AFB(1). Cytotoxicity assay showed that the GNMT group had higher survival rate than the control group after they were treated with AFB(1). Automated docking experiments showed that AFB(1) binds to the S-adenosylmethionine binding domain of GNMT. Affinity sensor assay demonstrated that the dissociation constant for GNMT-AFB(1) interaction is 44.9 microM. Therefore, GNMT is a tumor suppressor for HCC and it exerts protective effects in hepatocytes via direct interaction with AFB(1), resulting in reduced AFB(1)-DNA adducts formation and cell death.
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Affiliation(s)
- Chia-Hung Yen
- Division of Molecular Medicine, Institute of Public Health, School of Medicine, National Yang-Ming University, Taipei, Taiwan
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Huang YC, Chen M, Shyr YM, Su CH, Chen CK, Li AFY, Ho DMT, Chen YMA. Glycine N-methyltransferase is a favorable prognostic marker for human cholangiocarcinoma. J Gastroenterol Hepatol 2008; 23:1384-9. [PMID: 18624901 DOI: 10.1111/j.1440-1746.2008.05488.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND AIM Glycine N-methyltransferase (GNMT) is a susceptibility gene for human hepatocellular carcinoma (HCC). We previously reported that GNMT expression is diminished in HCC. Here we report our examination of GNMT expression patterns in cholangiocarcinoma and the relationship between its expression and prognosis. METHODS We analyzed GNMT expression in tumor tissues from 33 cholangiocarcinoma patients (19 male) using immunohistochemistry (IHC) procedures with a GNMT monoclonal antibody (mAb 4-17). GNMT expression intensity and percentages were scored on a scale of 0 to 6. The association between GNMT expression and survival was analyzed using the Kaplan-Meier method, and prognostic factors were evaluated with a multivariate Cox proportional hazards regression model. RESULTS High GNMT expression was found in epithelial cells of normal bile ducts. Six of 33 (18.2%) cholangiocarcinoma tissues had no GNMT expression. A statistically significant difference was noted in GNMT expression between male and female patients (68.4% vs 100%, P < 0.05). Compared to patients with GNMT expression scores > 3, the death hazard ratio for patients with GNMT scores <or= 3 was 3.68 (95% confidence interval = 1.17-11.59, P < 0.05). CONCLUSIONS GNMT expression is a favorable prognosis predictor for cholangiocarcinoma.
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Affiliation(s)
- Yu-Chuen Huang
- AIDS Prevention and Research Center, National Yang-Ming University, Taipei, Taiwan
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46
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Luz Martínez-Chantar M, Vázquez-Chantada M, Ariz U, Martínez N, Varela M, Luka Z, Capdevila A, Rodríguez J, Aransay AM, Matthiesen R, Yang H, Calvisi DF, Esteller M, Fraga M, Lu SC, Wagner C, Mato JM. Loss of the glycine N-methyltransferase gene leads to steatosis and hepatocellular carcinoma in mice. Hepatology 2008; 47:1191-9. [PMID: 18318442 PMCID: PMC2405897 DOI: 10.1002/hep.22159] [Citation(s) in RCA: 236] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
UNLABELLED Glycine N-methyltransferase (GNMT) is the main enzyme responsible for catabolism of excess hepatic S-adenosylmethionine (SAMe). GNMT is absent in hepatocellular carcinoma (HCC), messenger RNA (mRNA) levels are significantly lower in livers of patients at risk of developing HCC, and GNMT has been proposed to be a tumor-susceptibility gene for liver cancer. The identification of several children with liver disease as having mutations of the GNMT gene further suggests that this enzyme plays an important role in liver function. In the current study we studied development of liver pathologies including HCC in GNMT-knockout (GNMT-KO) mice. GNMT-KO mice have elevated serum aminotransferase, methionine, and SAMe levels and develop liver steatosis, fibrosis, and HCC. We found that activation of the Ras and Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways was increased in liver tumors from GNMT-KO mice coincidently with the suppression of the Ras inhibitors Ras-association domain family/tumor suppressor (RASSF) 1 and 4 and the JAK/STAT inhibitors suppressor of cytokine signaling (SOCS) 1-3 and cytokine-inducible SH2-protein. Finally, we found that methylation of RASSF1 and SOCS2 promoters and the binding of trimethylated lysine 27 in histone 3 to these 2 genes was increased in HCC from GNMT-KO mice. CONCLUSION These data demonstrate that loss of GNMT induces aberrant methylation of DNA and histones, resulting in epigenetic modulation of critical carcinogenic pathways in mice.
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Affiliation(s)
| | | | - Usue Ariz
- CIC bioGUNE, CIBERehd, Technology Park of Bizkaia, Bizkaia, Spain
| | - Nuria Martínez
- CIC bioGUNE, CIBERehd, Technology Park of Bizkaia, Bizkaia, Spain
| | - Marta Varela
- CIC bioGUNE, CIBERehd, Technology Park of Bizkaia, Bizkaia, Spain
| | - Zigmund Luka
- Department of Biochemistry, Vanderbilt University, Nashville, TN
| | | | - Juan Rodríguez
- CIC bioGUNE, CIBERehd, Technology Park of Bizkaia, Bizkaia, Spain
| | - Ana M. Aransay
- CIC bioGUNE, CIBERehd, Technology Park of Bizkaia, Bizkaia, Spain
| | - Rune Matthiesen
- CIC bioGUNE, CIBERehd, Technology Park of Bizkaia, Bizkaia, Spain
| | - Heping Yang
- Division of Gastrointestinal and Liver Diseases, Keck School of Medicine, University Southern California, Los Angeles, CA
| | - Diego F. Calvisi
- Division of Experimental Pathology and Oncology, University of Sassary, Sassary, Italy
| | - Manel Esteller
- Centro Nacional de Investigaciones Oncológicas, Madrid, Spain
| | - Mario Fraga
- Centro Nacional de Investigaciones Oncológicas, Madrid, Spain
| | - Shelly C. Lu
- Division of Gastrointestinal and Liver Diseases, Keck School of Medicine, University Southern California, Los Angeles, CA
| | - Conrad Wagner
- Department of Biochemistry, Vanderbilt University, Nashville, TN,Tennessee Valley Department of Medical Affairs Medical Center, Nashville, TN
| | - José M. Mato
- CIC bioGUNE, CIBERehd, Technology Park of Bizkaia, Bizkaia, Spain
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Husain S. Literature overview: Microbial metabolism of high molecular weight polycyclic aromatic hydrocarbons. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/rem.20165] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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48
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Liu SP, Li YS, Chen YJ, Chiang EP, Li AFY, Lee YH, Tsai TF, Hsiao M, Huang SF, Chen YMA, Chen YMA. Glycine N-methyltransferase-/- mice develop chronic hepatitis and glycogen storage disease in the liver. Hepatology 2007; 46:1413-25. [PMID: 17937387 DOI: 10.1002/hep.21863] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
UNLABELLED Glycine N-methyltransferase (GNMT) affects genetic stability by regulating DNA methylation and interacting with environmental carcinogens. To establish a Gnmt knockout mouse model, 2 lambda phage clones containing a mouse Gnmt genome were isolated. At 11 weeks of age, the Gnmt-/- mice had hepatomegaly, hypermethioninemia, and significantly higher levels of both serum alanine aminotransferase and hepatic S-adenosylmethionine. Such phenotypes mimic patients with congenital GNMT deficiencies. A real-time polymerase chain reaction analysis of 10 genes in the one-carbon metabolism pathway revealed that 5,10-methylenetetrahydrofolate reductase, S-adenosylhomocysteine hydrolase (Ahcy), and formiminotransferase cyclodeaminase (Ftcd) were significantly down-regulated in Gnmt-/- mice. This report demonstrates that GNMT regulates the expression of both Ftcd and Ahcy genes. Results from pathological examinations indicated that 57.1% (8 of 14) of the Gnmt-/- mice had glycogen storage disease (GSD) in their livers. Focal necrosis was observed in male Gnmt-/- livers, whereas degenerative changes were found in the intermediate zones of female Gnmt-/- livers. In addition, hypoglycemia, increased serum cholesterol, and significantly lower numbers of white blood cells, neutrophils, and monocytes were observed in the Gnmt-/- mice. A real-time polymerase chain reaction analysis of genes involved in the gluconeogenesis pathways revealed that the following genes were significantly down-regulated in Gnmt-/- mice: fructose 1,6-bisphosphatase, phosphoenolpyruvate carboxykinase, and glucose-6-phosphate transporter. CONCLUSION Because Gnmt-/- mice phenotypes mimic those of patients with GNMT deficiencies and share several characteristics with GSD Ib patients, we suggest that they are useful for studies of the pathogenesis of congenital GNMT deficiencies and the role of GNMT in GSD and liver tumorigenesis.
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Affiliation(s)
- Shih-Ping Liu
- Division of Preventive Medicine, Institute of Public Health, School of Medicine, Taipei, Taiwan
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Chen CY, Ping YH, Lee HC, Chen KH, Lee YM, Chan YJ, Lien TC, Jap TS, Lin CH, Kao LS, Chen YMA. Open reading frame 8a of the human severe acute respiratory syndrome coronavirus not only promotes viral replication but also induces apoptosis. J Infect Dis 2007; 196:405-15. [PMID: 17597455 PMCID: PMC7204190 DOI: 10.1086/519166] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Accepted: 01/23/2007] [Indexed: 01/20/2023] Open
Abstract
Background. A unique genomic difference between human and civet severe acute respiratory syndrome coronaviruses (SARS-CoVs) is that the former has a deletion of 29 nucleotides from open reading frame (orf) 8d that results in the generation of orf8a and orf8b. The objectives of the present study were to analyze antibody reactivity to ORF8a in patients with SARS and to elucidate the function of ORF8a. Methods. Western-blot and immunofluorescent antibody assays were used to detect anti-ORF8a antibody. SARS-CoV HKU39849 was used to infect stable clones expressing ORF8a and cells transfected with small interfering RNA (siRNA). The virus loads (VLs) and cytopathic effects (CPEs) were recorded. Confocal microscopy and several mitochondria-related tests were used to study the function of ORF8a. Results. Two (5.4%) of 37 patients with SARS had anti-ORF8a antibodies. The VLs in the stable clones expressing ORF8a were significantly higher than those in control subjects 5 days after infection. siRNA against orf8a significantly reduced VLs and interrupted the CPE. ORF8a was found to be localized in mitochondria, and overexpression resulted in increases in mitochondrial transmembrane potential, reactive oxygen species production, caspase 3 activity, and cellular apoptosis. Conclusions. ORF8a not only enhances viral replication but also induces apoptosis through a mitochondria-dependent pathway.
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Affiliation(s)
- Chia-Yen Chen
- Istitute of Public Health, Taipei, Taiwan, Republic of China
- AIDS Prevention and Research Center, Taipei, Taiwan, Republic of China
| | - Yueh-Hsin Ping
- Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Hsin-Chen Lee
- Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Kuan-Hsuan Chen
- AIDS Prevention and Research Center, Taipei, Taiwan, Republic of China
| | - Yuan-Ming Lee
- Istitute of Public Health, Taipei, Taiwan, Republic of China
- Division of Clinical Virology, Department of Pathology and Laboratory Medicine, Taipei, Taiwan, Republic of China
| | - Yu-Juin Chan
- Division of Clinical Virology, Department of Pathology and Laboratory Medicine, Taipei, Taiwan, Republic of China
| | - Te-Cheng Lien
- Department of Respiratory Therapy, Taipei, Taiwan, Republic of China
| | - Tjin-Shing Jap
- Section of Biochemistry, Department of Pathology and Laboratory Medicine, Veterans General Hospital, Taipei, Taiwan, Republic of China
| | - Chi-Hung Lin
- Institute of Microbiology and Immunology, Taipei, Taiwan, Republic of China
| | - Lung-Sen Kao
- Faculty of Life Science, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Yi-Ming Arthur Chen
- Istitute of Public Health, Taipei, Taiwan, Republic of China
- AIDS Prevention and Research Center, Taipei, Taiwan, Republic of China
- Reprints or correspondence: Prof. Yi-Ming A Chen, AIDS Prevention and Research Center, National Yang-Ming University, Li-Noun Street, Section 2, Taipei, Taiwan 112 ()
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50
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Huang YC, Lee CM, Chen M, Chung MY, Chang YH, Huang WJS, Ho DMT, Pan CC, Wu TT, Yang S, Lin MW, Hsieh JT, Chen YMA. Haplotypes, loss of heterozygosity, and expression levels of glycine N-methyltransferase in prostate cancer. Clin Cancer Res 2007; 13:1412-20. [PMID: 17332283 DOI: 10.1158/1078-0432.ccr-06-1551] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Glycine N-methyltransferase (GNMT) affects genetic stability by regulating DNA methylation and interacting with environmental carcinogens. In a previous study, we showed that GNMT acts as a susceptibility gene for hepatocellular carcinoma. Here, we report on our efforts to characterize the haplotypes, loss of heterozygosity (LOH), and expression levels of the GNMT in prostate cancer. EXPERIMENTAL DESIGN Peripheral blood mononuclear cell DNA collected from 326 prostate cancer patients and 327 age-matched controls was used to determine GNMT haplotypes. Luciferase reporter constructs were used to compare the promoter activity of different GNMT haplotypes. GNMT LOH rates in tumorous specimens were investigated via a comparison with peripheral blood mononuclear cell genotypes. Immunohistochemical staining was used to analyze GNMT expression in tissue specimens collected from 5 normal individuals, 33 benign prostatic hyperplasia patients, and 45 prostate cancer patients. RESULTS Three major GNMT haplotypes were identified in 92% of the participants: A, 16GAs/DEL/C (58%); B, 10GAs/INS/C (19.9%); and C, 10GAs/INS/T (14.5%). Haplotype C carriers had significantly lower risk for prostate cancer compared with individuals with haplotype A (odds ratio, 0.68; 95% confidence interval, 0.48-0.95). Results from a phenotypic analysis showed that haplotype C exhibited the highest promoter activity (P < 0.05, ANOVA test). In addition, 36.4% (8 of 22) of the prostatic tumor tissues had LOH of the GNMT gene. Immunohistochemical staining results showed abundant GNMT expression in normal prostatic and benign prostatic hyperplasia tissues, whereas it was diminished in 82.2% (37 of 45) of the prostate cancer tissues. CONCLUSIONS Our findings suggest that GNMT is a tumor susceptibility gene for prostate cancer.
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Affiliation(s)
- Yu-Chuen Huang
- Division of Preventive Medicine, Institute of Public Health, National Yang-Ming University, Taipei, Taiwan
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