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Nieschalke K, Bergau N, Jessel S, Seidel A, Baldermann S, Schreiner M, Abraham K, Lampen A, Monien BH, Kleuser B, Glatt H, Schumacher F. Urinary Excretion of Mercapturic Acids of the Rodent Carcinogen Methyleugenol after a Single Meal of Basil Pesto: A Controlled Exposure Study in Humans. Chem Res Toxicol 2023; 36:1753-1767. [PMID: 37875262 PMCID: PMC10664145 DOI: 10.1021/acs.chemrestox.3c00212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Indexed: 10/26/2023]
Abstract
Methyleugenol (ME), found in numerous plants and spices, is a rodent carcinogen and is classified as "possibly carcinogenic to humans". The hypothesis of a carcinogenic risk for humans is supported by the observation of ME-derived DNA adducts in almost all human liver and lung samples examined. Therefore, a risk assessment of ME is needed. Unfortunately, biomarkers of exposure for epidemiological studies are not yet available. We hereby present the first detection of N-acetyl-l-cysteine conjugates (mercapturic acids) of ME in human urine samples after consumption of a popular ME-containing meal, pasta with basil pesto. We synthesized mercapturic acid conjugates of ME, identified the major product as N-acetyl-S-[3'-(3,4-dimethoxyphenyl)allyl]-l-cysteine (E-3'-MEMA), and developed methods for its extraction and LC-MS/MS quantification in human urine. For conducting an exposure study in humans, a basil cultivar with a suitable ME content was grown for the preparation of basil pesto. A defined meal containing 100 g of basil pesto, corresponding to 1.7 mg ME, was served to 12 participants, who collected the complete urine at defined time intervals for 48 h. Using d6-E-3'-MEMA as an internal standard for LC-MS/MS quantification, we were able to detect E-3'-MEMA in urine samples of all participants collected after the ME-containing meal. Excretion was maximal between 2 and 6 h after the meal and was completed within about 12 h (concentrations below the limit of detection). Excreted amounts were only between 1 and 85 ppm of the ME intake, indicating that the ultimate genotoxicant, 1'-sulfooxy-ME, is formed to a subordinate extent or is not efficiently detoxified by glutathione conjugation and subsequent conversion to mercapturic acids. Both explanations may apply cumulatively, with the ubiquitous detection of ME DNA adducts in human lung and liver specimens arguing against an extremely low formation of 1'-sulfooxy-ME. Taken together, we hereby present the first noninvasive human biomarker reflecting an internal exposure toward reactive ME species.
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Affiliation(s)
- Kai Nieschalke
- Department
of Nutritional Toxicology, Institute of Nutritional Science, University of Potsdam, 14558 Nuthetal, Germany
- Department
of Food Safety, German Federal Institute
for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Nick Bergau
- Department
of Food Safety, German Federal Institute
for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Sönke Jessel
- Biochemical
Institute for Environmental Carcinogens, Prof. Dr. Gernot Grimmer-Foundation, 22927 Grosshansdorf, Germany
| | - Albrecht Seidel
- Biochemical
Institute for Environmental Carcinogens, Prof. Dr. Gernot Grimmer-Foundation, 22927 Grosshansdorf, Germany
| | - Susanne Baldermann
- Department
Plant Quality and Food Security, Leibniz
Institute of Vegetable and Ornamental Crops (IGZ), 14979 Grossbeeren, Germany
- Faculty of
Life Sciences: Food, Nutrition & Health, University of Bayreuth, 95326 Kulmbach, Germany
| | - Monika Schreiner
- Department
Plant Quality and Food Security, Leibniz
Institute of Vegetable and Ornamental Crops (IGZ), 14979 Grossbeeren, Germany
| | - Klaus Abraham
- Department
of Food Safety, German Federal Institute
for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Alfonso Lampen
- Department
of Food Safety, German Federal Institute
for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Bernhard H. Monien
- Department
of Food Safety, German Federal Institute
for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Burkhard Kleuser
- Department
of Nutritional Toxicology, Institute of Nutritional Science, University of Potsdam, 14558 Nuthetal, Germany
- Department
of Pharmacology and Toxicology, Institute of Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Hansruedi Glatt
- Department
of Food Safety, German Federal Institute
for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Fabian Schumacher
- Department
of Nutritional Toxicology, Institute of Nutritional Science, University of Potsdam, 14558 Nuthetal, Germany
- Department
of Pharmacology and Toxicology, Institute of Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
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Tsai HW, Cheng SW, Chen CC, Chen IW, Ho CL. A combined bioinformatics and experimental approach identifies RMI2 as a Wnt/β-catenin signaling target gene related to hepatocellular carcinoma. BMC Cancer 2023; 23:1025. [PMID: 37875822 PMCID: PMC10594864 DOI: 10.1186/s12885-023-10655-2] [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: 08/10/2022] [Accepted: 02/15/2023] [Indexed: 10/26/2023] Open
Abstract
BACKGROUND The Wnt/β-catenin signaling pathway plays an important role in embryogenesis and tumorigenesis. In human cancer, abnormal activity of Wnt/β-catenin signaling pathway induces overexpressed of downstream genes, and initiate oncogene. There are several target genes known to be key players in tumorigenesis, such as c-myc, cyclin D1, MMPs or survivin. Therefore, identifying the target genes of Wnt/β-catenin signaling pathway is important to understanding Wnt/β-catenin-mediated carcinogenesis. In this study, we developed a combined bioinformatics and experimental approach to find potential target genes. METHODS Luciferase reporter assay was used to analyze the promoter activity of RMI2. WST1 cell proliferation assays and transwell assays were performed to determine the proliferation and migration capacities of RMI2 overexpressing or knockdown stable hepatic cells. Finally, xenograft experiments were performed to measure the tumor formation capacity in vivo. RESULTS The results showed that RMI2 mRNA was upregulated after LiCl treatment and Wnt3a-conditioned medium in a culture of SK-hep-1 cell lines. A chromatin immunoprecipitation (ChIP) assay showed that the β-catenin/T cell-specific factor (TCF) complex binds to the putative TCF binding site of the RMI2 promoter. We then found a TCF binding site at - 333/- 326 of the RMI2 promoter, which is crucial for β-catenin responsiveness in liver cell lines. RMI2 was overexpressed in hepatoma tissue and cell lines, and it promoted the migration and invasion of HCC cells. Moreover, RMI2 upregulated the expression of epithelial-mesenchymal transition (EMT) markers and the Wnt3a/β-catenin-related genes, but silencing RMI2 had the opposite effects. Notably, the expression of RMI2 was positively correlated with the clinical data of HCC patients who had significantly shorter overall survival (OS) and disease-free survival (DFS) (Both: P < 0.05). In addition, a total of 373 HCC patients' data from the Caner Genome Atlas project (TCGA) were used to validate our findings. CONCLUSIONS Taking all these findings together, we determined that RMI2 was a new target gene of the Wnt/β-catenin signaling pathway. We also found that RMI2 promotes EMT markers, HCC cell invasion, and metastasis, which indicated that RMI2 is a potential target for preventing or at least mitigating the progression of HCC.
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Affiliation(s)
- Hung-Wen Tsai
- Department of Pathology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan City, 704, Taiwan
| | - Shu-Wen Cheng
- Department of Pathology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan City, 704, Taiwan
| | - Chou-Cheng Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Business Management, CTBC Business School, Tainan, Taiwan
| | - I-Wen Chen
- Department of Pathology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan City, 704, Taiwan
| | - Chung-Liang Ho
- Department of Pathology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, 138 Sheng-Li Road, Tainan City, 704, Taiwan.
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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Carlsson MJ, Vollmer AS, Demuth P, Heylmann D, Reich D, Quarz C, Rasenberger B, Nikolova T, Hofmann TG, Christmann M, Fuhlbrueck JA, Stegmüller S, Richling E, Cartus AT, Fahrer J. p53 triggers mitochondrial apoptosis following DNA damage-dependent replication stress by the hepatotoxin methyleugenol. Cell Death Dis 2022; 13:1009. [PMID: 36446765 PMCID: PMC9708695 DOI: 10.1038/s41419-022-05446-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 12/03/2022]
Abstract
Liver cancer is one of the most frequent tumor entities worldwide, which is causally linked to viral infection, fatty liver disease, life-style factors and food-borne carcinogens, particularly aflatoxins. Moreover, genotoxic plant toxins including phenylpropenes are suspected human liver carcinogens. The phenylpropene methyleugenol (ME) is a constituent of essential oils in many plants and occurs in herbal medicines, food, and cosmetics. Following its uptake, ME undergoes Cytochrome P450 (CYP) and sulfotransferase 1A1 (SULT1A1)-dependent metabolic activation, giving rise to DNA damage. However, little is known about the cellular response to the induced DNA adducts. Here, we made use of different SULT1A1-proficient cell models including primary hepatocytes that were treated with 1'-hydroxymethyleugenol (OH-ME) as main phase I metabolite. Firstly, mass spectrometry showed a concentration-dependent formation of N2-MIE-dG as major DNA adduct, strongly correlating with SULT1A1 expression as attested in cells with and without human SULT1A1. ME-derived DNA damage activated mainly the ATR-mediated DNA damage response as shown by phosphorylation of CHK1 and histone 2AX, followed by p53 accumulation and CHK2 phosphorylation. Consistent with these findings, the DNA adducts decreased replication speed and caused replication fork stalling. OH-ME treatment reduced viability particularly in cell lines with wild-type p53 and triggered apoptotic cell death, which was rescued by pan-caspase-inhibition. Further experiments demonstrated mitochondrial apoptosis as major cell death pathway. ME-derived DNA damage caused upregulation of the p53-responsive genes NOXA and PUMA, Bax activation, and cytochrome c release followed by caspase-9 and caspase-3 cleavage. We finally demonstrated the crucial role of p53 for OH-ME triggered cell death as evidenced by reduced pro-apoptotic gene expression, strongly attenuated Bax activation and cell death inhibition upon genetic knockdown or pharmacological inhibition of p53. Taken together, our study demonstrates for the first time that ME-derived DNA damage causes replication stress and triggers mitochondrial apoptosis via the p53-Bax pathway.
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Affiliation(s)
- Max J. Carlsson
- grid.7645.00000 0001 2155 0333Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Anastasia S. Vollmer
- grid.8664.c0000 0001 2165 8627Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, 35392 Giessen, Germany ,grid.411544.10000 0001 0196 8249Present Address: Department of Dermatology, University Medical Center, 69120 Heidelberg, Germany
| | - Philipp Demuth
- grid.7645.00000 0001 2155 0333Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Daniel Heylmann
- grid.8664.c0000 0001 2165 8627Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Diana Reich
- grid.410607.4Institute of Toxicology, University Medical Center, Johannes Gutenberg University Mainz, 55131 Mainz, Germany
| | - Caroline Quarz
- grid.7645.00000 0001 2155 0333Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Birgit Rasenberger
- grid.410607.4Institute of Toxicology, University Medical Center, Johannes Gutenberg University Mainz, 55131 Mainz, Germany
| | - Teodora Nikolova
- grid.410607.4Institute of Toxicology, University Medical Center, Johannes Gutenberg University Mainz, 55131 Mainz, Germany
| | - Thomas G. Hofmann
- grid.410607.4Institute of Toxicology, University Medical Center, Johannes Gutenberg University Mainz, 55131 Mainz, Germany
| | - Markus Christmann
- grid.410607.4Institute of Toxicology, University Medical Center, Johannes Gutenberg University Mainz, 55131 Mainz, Germany
| | - Julia A. Fuhlbrueck
- grid.7645.00000 0001 2155 0333Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Simone Stegmüller
- grid.7645.00000 0001 2155 0333Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Elke Richling
- grid.7645.00000 0001 2155 0333Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Alexander T. Cartus
- grid.7645.00000 0001 2155 0333Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Jörg Fahrer
- grid.7645.00000 0001 2155 0333Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, 67663 Kaiserslautern, Germany ,grid.8664.c0000 0001 2165 8627Rudolf Buchheim Institute of Pharmacology, Justus Liebig University Giessen, 35392 Giessen, Germany ,grid.410607.4Institute of Toxicology, University Medical Center, Johannes Gutenberg University Mainz, 55131 Mainz, Germany
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4
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Myristicin and Elemicin: Potentially Toxic Alkenylbenzenes in Food. Foods 2022; 11:foods11131988. [PMID: 35804802 PMCID: PMC9265716 DOI: 10.3390/foods11131988] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/22/2022] [Accepted: 07/01/2022] [Indexed: 11/17/2022] Open
Abstract
Alkenylbenzenes represent a group of naturally occurring substances that are synthesized as secondary metabolites in various plants, including nutmeg and basil. Many of the alkenylbenzene-containing plants are common spice plants and preparations thereof are used for flavoring purposes. However, many alkenylbenzenes are known toxicants. For example, safrole and methyleugenol were classified as genotoxic carcinogens based on extensive toxicological evidence. In contrast, reliable toxicological data, in particular regarding genotoxicity, carcinogenicity, and reproductive toxicity is missing for several other structurally closely related alkenylbenzenes, such as myristicin and elemicin. Moreover, existing data on the occurrence of these substances in various foods suffer from several limitations. Together, the existing data gaps regarding exposure and toxicity cause difficulty in evaluating health risks for humans. This review gives an overview on available occurrence data of myristicin, elemicin, and other selected alkenylbenzenes in certain foods. Moreover, the current knowledge on the toxicity of myristicin and elemicin in comparison to their structurally related and well-characterized derivatives safrole and methyleugenol, especially with respect to their genotoxic and carcinogenic potential, is discussed. Finally, this article focuses on existing data gaps regarding exposure and toxicity currently impeding the evaluation of adverse health effects potentially caused by myristicin and elemicin.
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5
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Yamada T, Ohara A, Ozawa N, Maeda K, Kondo M, Okuda Y, Abe J, Cohen SM, Lake BG. Comparison of the Hepatic Effects of Phenobarbital in Chimeric Mice Containing Either Rat or Human Hepatocytes With Humanized Constitutive Androstane Receptor and Pregnane X Receptor Mice. Toxicol Sci 2021; 177:362-376. [PMID: 32735318 DOI: 10.1093/toxsci/kfaa125] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Using a chimeric mouse humanized liver model, we provided evidence that human hepatocytes are refractory to the mitogenic effects of rodent constitutive androstane receptor (CAR) activators. To evaluate the functional reliability of this model, the present study examined mitogenic responses to phenobarbital (PB) in chimeric mice transplanted with rat hepatocytes, because rats are responsive to CAR activators. Treatment with 1000 ppm PB for 7 days significantly increased replicative DNA synthesis (RDS) in rat hepatocytes of the chimeric mice, demonstrating that the transplanted hepatocyte model is functionally reliable for cell proliferation analysis. Treatment of humanized CAR and pregnane X receptor (PXR) mice (hCAR/hPXR mice) with 1000 ppm PB for 7 days significantly increased hepatocyte RDS together with increases in several mitogenic genes. Global gene expression analysis was performed with liver samples from this and from previous studies focusing on PB-induced Wnt/β-catenin signaling and showed that altered genes in hCAR/hPXR mice clustered most closely with liver tumor samples from a diethylnitrosamine/PB initiation/promotion study than with wild-type mice. However, different gene clusters were observed for chimeric mice with human hepatocytes for Wnt/β-catenin signaling when compared with those of hCAR/hPXR mice, wild-type mice, and liver tumor samples. The results of this study demonstrate clear differences in the effects of PB on hepatocyte RDS and global gene expression between human hepatocytes of chimeric mice and hCAR/hPXR mice, suggesting that the chimeric mouse model is relevant to humans for studies on the hepatic effects of rodent CAR activators whereas the hCAR/hPXR mouse is not.
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Affiliation(s)
| | - Ayako Ohara
- Bioscience Research Laboratory, Sumitomo Chemical Company, Ltd, Konohana-ku, Osaka 554-8558, Japan
| | - Naoya Ozawa
- Bioscience Research Laboratory, Sumitomo Chemical Company, Ltd, Konohana-ku, Osaka 554-8558, Japan
| | | | | | - Yu Okuda
- Environmental Health Science Laboratory
| | - Jun Abe
- Environmental Health Science Laboratory
| | - Samuel M Cohen
- Department of Pathology and Microbiology, Havlik-Wall Professor of Oncology, University of Nebraska Medical Center, Omaha, Nebraska 68198-3135
| | - Brian G Lake
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
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Apolinário LA, Ramalho LNZ, Moosavi MH, Jager AV, Augusto MJ, Trotta MR, Petta T, Khaneghah AM, Oliveira CAF, Ramalho FS. Oncogenic and tumor suppressor pathways in subchronic aflatoxicosis in rats: Association with serum and urinary aflatoxin exposure biomarkers. Food Chem Toxicol 2021; 153:112263. [PMID: 34015426 DOI: 10.1016/j.fct.2021.112263] [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: 10/29/2020] [Revised: 04/29/2021] [Accepted: 05/10/2021] [Indexed: 11/17/2022]
Abstract
In this study, the changes in oncogenic and tumor suppressor signaling pathways in liver and their association with serum and urinary biomarkers of aflatoxin exposure were evaluated in Wistar rats fed diets containing aflatoxin B1 (AFB1) for 90 days. Rats were divided into four groups (n = 15 per group) and assigned to dietary treatments containing 0 (control), 50 (AFB50), 100 (AFB100) and 200 μg AFB1 kg-1 diet (AFB200). Multiple preneoplastic foci of hepatocytes marked with glutathione-S-transferase-placental form (GST-P) were identified in AFB100 and AFB200 groups. Hepatocellular damage induced by AFB1 resulted in overexpression of cyclin D1 and β-catenin. The liver expression of retinoblastoma (Rb) and p27Kip1 decreased in AFB100 and AFB200 groups, confirming the favorable conditions for neoplastic progression to hepatocellular carcinoma. All samples from rats fed AFB1-contaminated diets had quantifiable AFB1-lysine in serum or urinary AFM1 and AFB1-N7-guanine, with mean levels of 20.42-50.34 ng mL-1, 5.31-37.68 and 39.15-126.37 ng mg-1 creatinine, respectively. Positive correlations were found between AFB1-lysine, AFM1 or AFB1-N7-guanine and GST-P+, β-catenin+ and cyclin D1+ hepatocytes, while Rb + cells negatively correlated with those AFB1 exposure biomarkers. The pathways evaluated are critical molecular mechanisms of AFB1-induced hepatocarcinogenesis in rats.
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Affiliation(s)
- Letícia A Apolinário
- Department of Pathology and Legal Medicine, School of Medicine at Ribeirão Preto, University of São Paulo, Av. do Café, s/n, CEP, 14040-903, Ribeirão Preto, SP, Brazil
| | - Leandra N Z Ramalho
- Department of Pathology and Legal Medicine, School of Medicine at Ribeirão Preto, University of São Paulo, Av. do Café, s/n, CEP, 14040-903, Ribeirão Preto, SP, Brazil
| | - Motahareh Hashemi Moosavi
- Department of Food Science and Technology, National Nutrition and Food Technology Research Institute, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Alessandra V Jager
- Department of Bio Molecular Sciences, School of Pharmaceutical Sciences at Ribeirão Preto, University of São Paulo, Av. do Café, s/n, CEP, 14040-903, Ribeirão Preto, SP, Brazil
| | - Marlei J Augusto
- Department of Pathology and Legal Medicine, School of Medicine at Ribeirão Preto, University of São Paulo, Av. do Café, s/n, CEP, 14040-903, Ribeirão Preto, SP, Brazil
| | - Maurício R Trotta
- Department of Pathology and Legal Medicine, School of Medicine at Ribeirão Preto, University of São Paulo, Av. do Café, s/n, CEP, 14040-903, Ribeirão Preto, SP, Brazil
| | - Tânia Petta
- Actinobac Agrosciences. Supera - Parque de Inovação e Tecnologia de Ribeirão Preto, Av. Dra. Nadir Águiar, 1805, CEP, 14056-680, Ribeirão Preto, SP, Brazil
| | - Amin Mousavi Khaneghah
- Department of Food Science, Faculty of Food Engineering, University of Campinas (UNICAMP). R. Monteiro Lobato, 80, CEP, 13083-862, Campinas, SP, Brazil
| | - Carlos A F Oliveira
- Department of Food Engineering, School of Animal Science and Food Engineering, University of São Paulo. Av. Duque de Caxias Norte, 225, CEP, 13635-900, Pirassununga, SP, Brazil.
| | - Fernando S Ramalho
- Department of Pathology and Legal Medicine, School of Medicine at Ribeirão Preto, University of São Paulo, Av. do Café, s/n, CEP, 14040-903, Ribeirão Preto, SP, Brazil
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7
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Kurosaki S, Nakagawa H, Hayata Y, Kawamura S, Matsushita Y, Yamada T, Uchino K, Hayakawa Y, Suzuki N, Hata M, Tsuboi M, Kinoshita H, Tanaka Y, Nakatsuka T, Hirata Y, Tateishi K, Koike K. Cell fate analysis of zone 3 hepatocytes in liver injury and tumorigenesis. JHEP Rep 2021; 3:100315. [PMID: 34345813 PMCID: PMC8319533 DOI: 10.1016/j.jhepr.2021.100315] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 05/04/2021] [Accepted: 05/07/2021] [Indexed: 12/13/2022] Open
Abstract
Background & Aims Liver lobules are typically subdivided into 3 metabolic zones: zones 1, 2, and 3. However, the contribution of zonal differences in hepatocytes to liver regeneration, as well as to carcinogenic susceptibility, remains unclear. Methods We developed a new method for sustained genetic labelling of zone 3 hepatocytes and performed fate tracing to monitor these cells in multiple mouse liver tumour models. Results We first examined changes in the zonal distribution of the Wnt target gene Axin2 over time using Axin2-CreERT2;Rosa26-Lox-Stop-Lox-tdTomato mice (Axin2;tdTomato). We found that following tamoxifen administration at 3 weeks of age, approximately one-third of total hepatocytes that correspond to zone 3 were labelled in Axin2;tdTomato mice; the tdTomato+ cell distribution closely matched that of the zone 3 marker CYP2E1. Cell fate analysis revealed that zone 3 hepatocytes maintained their own lineage but rarely proliferated beyond their liver zonation during homoeostasis; this indicated that our protocol enabled persistent genetic labelling of zone 3 hepatocytes. Using this system, we found that zone 3 hepatocytes generally had high neoplastic potential, which was promoted by constitutive activation of Wnt/β-catenin signalling in the pericentral area. However, the frequency of zone 3 hepatocyte-derived tumours varied depending on the regeneration pattern of the liver parenchyma in response to liver injury. Notably, Axin2-expressing hepatocytes undergoing chronic liver injury significantly contributed to liver regeneration and possessed high neoplastic potential. Additionally, we revealed that the metabolic phenotypes of liver tumours were acquired during tumorigenesis, irrespective of their spatial origin. Conclusions Hepatocytes receiving Wnt/β-catenin signalling from their microenvironment have high neoplastic potential, and Wnt/β-catenin signalling is a potential drug target for the prevention of hepatocellular carcinoma. Lay summary Lineage tracing revealed that zone 3 hepatocytes residing in the pericentral niche have high neoplastic potential. Under chronic liver injury, hepatocytes receiving Wnt/β-catenin signalling broadly exist across all hepatic zones and significantly contribute to liver tumorigenesis as well as liver regeneration. Wnt/β-catenin signalling is a potential drug target for the prevention of hepatocellular carcinoma. We developed a new method for sustained genetic labelling of Zone 3 hepatocytes. Lineage tracing revealed that Zone 3 hepatocytes generally have high neoplastic potential. The frequency of Zone 3 hepatocyte-derived tumours varied depending on the regeneration pattern of liver parenchyma. Under chronic liver injury, hepatocytes receiving Wnt/β-catenin signalling significantly contributed to tumorigenesis. Wnt/β-catenin signalling is a potential drug target for the prevention of HCC.
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Key Words
- CDAHFD, choline-deficient l-amino acid-defined, high-fat diet
- CPS1, carbamoyl phosphate synthetase 1
- CYP2E1, cytochrome P450 subfamily 2E1
- DEN, diethylnitrosamine
- GS, glutamine synthetase
- HAL, histidine ammonia lyase
- HCC, hepatocellular carcinoma
- HFD, high-fat diet
- Hepatocellular carcinoma
- IF, immunofluorescence
- ISH, in situ hybridisation
- Liver regeneration
- MAFLD, metabolic dysfunction-associated fatty liver disease
- MUP, major urinary protein
- Metabolic dysfunction-associated fatty liver disease
- Metabolic zonation
- ND, normal diet
- PIK3CATg, hepatocyte-specific transgenic mice harbouring mutant PIK3CA variant
- PP, periportal
- PV, perivenous
- RFP, red fluorescent protein
- TAM, tamoxifen
- TUNEL, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labelling
- WT, wild-type
- Wnt/β-catenin signal
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Affiliation(s)
| | - Hayato Nakagawa
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Yuki Hayata
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Satoshi Kawamura
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Yuki Matsushita
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Tomoharu Yamada
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Koji Uchino
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Yoku Hayakawa
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Nobumi Suzuki
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Masahiro Hata
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Mayo Tsuboi
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Hiroto Kinoshita
- Division of Gastroenterology, Institute for Adult Diseases, Asahi Life Foundation, Tokyo, Japan
| | - Yasuo Tanaka
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Takuma Nakatsuka
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Yoshihiro Hirata
- Division of Advanced Genome Medicine, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Keisuke Tateishi
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
| | - Kazuhiko Koike
- Department of Gastroenterology, The University of Tokyo, Tokyo, Japan
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8
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Yamada T, Cohen SM, Lake BG. Critical evaluation of the human relevance of the mode of action for rodent liver tumor formation by activators of the constitutive androstane receptor (CAR). Crit Rev Toxicol 2021; 51:373-394. [PMID: 34264181 DOI: 10.1080/10408444.2021.1939654] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Many nongenotoxic chemicals have been shown to produce liver tumors in mice and/or rats by a mode of action (MOA) involving activation of the constitutive androstane receptor (CAR). Studies with phenobarbital (PB) and other compounds have identified the key events for this MOA: CAR activation; increased hepatocellular proliferation; altered foci formation; and ultimately the development of adenomas/carcinomas. In terms of human relevance, the pivotal species difference is that CAR activators are mitogenic agents in mouse and rat hepatocytes, but they do not stimulate increased hepatocellular proliferation in humans. This conclusion is supported by substantial in vitro studies with cultured rodent and human hepatocytes and also by in vivo studies with chimeric mice with human hepatocytes. Examination of the literature reveals many similarities in the hepatic effects and species differences between activators of rodent CAR and the peroxisome proliferator-activated receptor alpha (PPARα), with PPARα activators also not being mitogenic agents in human hepatocytes. Overall, a critical analysis of the available data demonstrates that the established MOA for rodent liver tumor formation by PB and other CAR activators is qualitatively not plausible for humans. This conclusion is supported by data from several human epidemiology studies.
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Affiliation(s)
- Tomoya Yamada
- Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd., Osaka, Japan
| | - Samuel M Cohen
- Department of Pathology and Microbiology, Havlik-Wall Professor of Oncology, University of Nebraska Medical Center, Nebraska Medical Center, Omaha, NE, USA
| | - Brian G Lake
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
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9
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Analysis of β-catenin gene mutations and gene expression in liver tumours of C57BL/10J mice produced by chronic administration of sodium phenobarbital. Toxicology 2019; 430:152343. [PMID: 31836555 DOI: 10.1016/j.tox.2019.152343] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/22/2019] [Accepted: 12/09/2019] [Indexed: 11/22/2022]
Abstract
In this study liver tumours produced in male and female mice of the low spontaneous liver tumour incidence C57BL/10J strain treated for 99 weeks with 1000 ppm in the diet with the model constitutive androstane receptor (CAR) activator sodium phenobarbital (NaPB) were analysed for β-catenin mutations by Western immunoblotting and DNA/RNA analysis. Some gene array analysis was also performed to identify genes involved in CAR activation and in β-catenin and Hras gene mutations. Analysis of 8 male and 2 female NaPB-induced liver tumour samples (comprising 2 adenomas, 6 carcinomas and 2 samples containing separate adenomas and carcinomas) revealed truncated β-catenin forms in just 4 male liver tumour samples, with the presence of the truncated β-catenin forms being confirmed by β-catenin exon 1-3 mutation analysis. Microarray gene expression analysis was performed with three of the NaPB-induced male mouse liver tumour samples where β-catenin mutations had not been identified by Western immunoblotting and DNA/RNA analysis and with three liver samples from both NaPB-induced non-tumour tissue and control animals. Treatment with NaPB resulted in induction of Cyp2b subfamily gene expression in both NaPB-induced mouse liver tumours and in NaPB-treated non-tumour tissue. In addition, the gene expression analysis demonstrated that the β-catenin and Hras pathways were not modified in NaPB-induced mouse liver tumours not exhibiting truncated β-catenin forms. Overall, while chronic administration of the model CAR activator NaPB results in both hepatocellular adenoma and carcinoma in the low spontaneous liver tumour incidence C57BL/10J mouse strain, only 40 % of the liver tumours evaluated in this study had β-catenin mutations. These results are in agreement with previous studies with the CAR activator oxazepam and demonstrate that mouse liver tumours induced by nongenotoxic CAR activators in the absence of initiation with a genotoxic agent are due to a number of mechanisms, including those largely independent of either the Wnt/β-catenin signalling pathway or Hras oncogene mutations.
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10
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Friemel J, Frick L, Unger K, Egger M, Parrotta R, Böge YT, Adili A, Karin M, Luedde T, Heikenwalder M, Weber A. Characterization of HCC Mouse Models: Towards an Etiology-Oriented Subtyping Approach. Mol Cancer Res 2019; 17:1493-1502. [PMID: 30967480 DOI: 10.1158/1541-7786.mcr-18-1045] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/18/2019] [Accepted: 04/03/2019] [Indexed: 11/16/2022]
Abstract
Murine liver tumors often fail to recapitulate the complexity of human hepatocellular carcinoma (HCC), which might explain the difficulty to translate preclinical mouse studies into clinical science. The aim of this study was to evaluate a subtyping approach for murine liver cancer models with regard to etiology-defined categories of human HCC, comparing genomic changes, histomorphology, and IHC profiles. Sequencing and analysis of gene copy-number changes [by comparative genomic hybridization (CGH)] in comparison with etiology-dependent subsets of HCC patients of The Cancer Genome Atlas (TCGA) database were conducted using specimens (75 tumors) of five different HCC mouse models: diethylnitrosamine (DEN) treated wild-type C57BL/6 mice, c-Myc and AlbLTαβ transgenic mice as well as TAK1LPC-KO and Mcl-1Δhep mice. Digital microscopy was used for the assessment of morphology and IHC of liver cell markers (A6-CK7/19, glutamine synthetase) in mouse and n = 61 human liver tumors. Tumor CGH profiles of DEN-treated mice and c-Myc transgenic mice matched alcohol-induced HCC, including morphologic findings (abundant inclusion bodies, fatty change) in the DEN model. Tumors from AlbLTαβ transgenic mice and TAK1LPC-KO models revealed the highest overlap with NASH-HCC CGH profiles. Concordant morphology (steatosis, lymphocyte infiltration, intratumor heterogeneity) was found in AlbLTαβ murine livers. CGH profiles from the Mcl-1Δhep model displayed similarities with hepatitis-induced HCC and characteristic human-like phenotypes (fatty change, intertumor and intratumor heterogeneity). IMPLICATIONS: Our findings demonstrate that stratifying preclinical mouse models along etiology-oriented genotypes and human-like phenotypes is feasible. This closer resemblance of preclinical models is expected to better recapitulate HCC subgroups and thus increase their informative value.
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Affiliation(s)
- Juliane Friemel
- Department of Pathology and Molecular Pathology, University and University Hospital Zurich, Zurich, Switzerland
| | - Lukas Frick
- Department of Pathology and Molecular Pathology, University and University Hospital Zurich, Zurich, Switzerland.,Swiss Hepato-Pancreato-Biliary Center, Department of Digestive and Transplant Surgery, University Hospital of Zurich, Zurich, Switzerland
| | - Kristian Unger
- Helmholtz Zentrum München Research Center for Environmental Health (GmbH), Research Unit Radiation Cytogenetics
| | - Michele Egger
- Department of Pathology and Molecular Pathology, University and University Hospital Zurich, Zurich, Switzerland
| | - Rossella Parrotta
- Department of Pathology and Molecular Pathology, University and University Hospital Zurich, Zurich, Switzerland
| | - Yannick T Böge
- Department of Pathology and Molecular Pathology, University and University Hospital Zurich, Zurich, Switzerland
| | - Arlind Adili
- Department of Pathology and Molecular Pathology, University and University Hospital Zurich, Zurich, Switzerland
| | - Michael Karin
- Department of Pathology, University of California, San Diego, California
| | - Tom Luedde
- Department of Medicine III, University Hospital RWTH Aachen, Aachen, Germany
| | - Mathias Heikenwalder
- Division Chronic Inflammation and Cancer, German Cancer Research Center, Heidelberg, Germany.
| | - Achim Weber
- Department of Pathology and Molecular Pathology, University and University Hospital Zurich, Zurich, Switzerland.
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11
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Auerbach SS, Xu M, Merrick BA, Hoenerhoff MJ, Phadke D, Taxman DJ, Shah R, Hong HHL, Ton TV, Kovi RC, Sills RC, Pandiri AR. Exome Sequencing of Fresh-frozen or Formalin-fixed Paraffin-embedded B6C3F1/N Mouse Hepatocellular Carcinomas Arising Either Spontaneously or due to Chronic Chemical Exposure. Toxicol Pathol 2018; 46:706-718. [PMID: 30045675 DOI: 10.1177/0192623318789398] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide; however, the mutational properties of HCC-associated carcinogens remain largely uncharacterized. We hypothesized that mechanisms underlying chemical-induced HCC can be characterized by evaluating the mutational spectra of these tumors. To test this hypothesis, we performed exome sequencing of B6C3F1/N HCCs that arose either spontaneously in vehicle controls ( n = 3) or due to chronic exposure to gingko biloba extract (GBE; n = 4) or methyleugenol (MEG; n = 3). Most archived tumor samples are available as formalin-fixed paraffin-embedded (FFPE) blocks, rather than fresh-frozen (FF) samples; hence, exome sequencing from paired FF and FFPE samples was compared. FF and FFPE samples showed 63% to 70% mutation concordance. Multiple known (e.g., Ctnnb1T41A, BrafV637E) and novel (e.g., Erbb4C559S, Card10A700V, and Klf11P358L) mutations in cancer-related genes were identified. The overall mutational burden was greater for MEG than for GBE or spontaneous HCC samples. To characterize the mutagenic mechanisms, we analyzed the mutational spectra in the HCCs according to their trinucleotide motifs. The MEG tumors clustered closest to Catalogue of Somatic Mutations in Cancer signatures 4 and 24, which are, respectively, associated with benzo(a)pyrene- and aflatoxin-induced HCCs in humans. These results establish a novel approach for classifying liver carcinogens and understanding the mechanisms of hepatocellular carcinogenesis.
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Affiliation(s)
- Scott S Auerbach
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
| | - Miaofei Xu
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
| | - B Alex Merrick
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
| | - Mark J Hoenerhoff
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA.,2 Unit for Laboratory Animal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Dhiral Phadke
- 3 Sciome LLC, Research Triangle Park, North Carolina, USA
| | - Debra J Taxman
- 3 Sciome LLC, Research Triangle Park, North Carolina, USA
| | - Ruchir Shah
- 3 Sciome LLC, Research Triangle Park, North Carolina, USA
| | - Hue-Hua L Hong
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
| | - Thai-Vu Ton
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
| | - Ramesh C Kovi
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA.,4 Experimental Pathology Laboratories Inc., Research Triangle Park, North Carolina, USA
| | - Robert C Sills
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
| | - Arun R Pandiri
- 1 Division of the National Toxicology Program, NIEHS, Research Triangle Park, North Carolina, USA
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12
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Lemberger UJ, Fuchs CD, Karer M, Haas S, Stojakovic T, Schöfer C, Marschall HU, Wrba F, Taketo MM, Egger G, Trauner M, Österreicher CH. Hepatocyte specific expression of an oncogenic variant of β-catenin results in cholestatic liver disease. Oncotarget 2018; 7:86985-86998. [PMID: 27895309 PMCID: PMC5349966 DOI: 10.18632/oncotarget.13521] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 09/26/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The Wnt/β-catenin signaling pathway plays a crucial role in embryonic development, tissue homeostasis, wound healing and malignant transformation in different organs including the liver. The consequences of continuous β-catenin signaling in hepatocytes remain elusive. RESULTS Livers of Ctnnb1CA hep mice were characterized by disturbed liver architecture, proliferating cholangiocytes and biliary type of fibrosis. Serum ALT and bile acid levels were significantly increased in Ctnnb1CA hep mice. The primary bile acid synthesis enzyme Cyp7a1 was increased whereas Cyp27 and Cyp8b1 were reduced in Ctnnb1CA hep mice. Expression of compensatory bile acid transporters including Abcb1, Abcb4, Abcc2 and Abcc4 were significantly increased in Ctnnb1CA hep mice while Ntcp was reduced. Accompanying changes of bile acid transporters favoring excretion of bile acids were observed in intestine and kidneys of Ctnnb1CA hep mice. Additionally, disturbed bile acid regulation through the FXR-FGF15-FGFR4 pathway was observed in mice with activated β-catenin. MATERIALS AND METHODS Mice with a loxP-flanked exon 3 of the Ctnnb1 gene were crossed to Albumin-Cre mice to obtain mice with hepatocyte-specific expression of a dominant stable form of β-catenin (Ctnnb1CA hep mice). Ctnnb1CA hep mice were analyzed by histology, serum biochemistry and mRNA profiling. CONCLUSIONS Expression of a dominant stable form of β-catenin in hepatocytes results in severe cholestasis and biliary type fibrosis.
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Affiliation(s)
- Ursula J Lemberger
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria.,Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria.,Hans Popper Laboratory for Molecular Hepatology, Department of Internal Medicine, Medical University of Vienna, Vienna, Austria
| | - Claudia D Fuchs
- Hans Popper Laboratory for Molecular Hepatology, Department of Internal Medicine, Medical University of Vienna, Vienna, Austria
| | - Matthias Karer
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Stefanie Haas
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Tatjana Stojakovic
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
| | - Christian Schöfer
- Department of Cell and Developmental Biology, Medical University of Vienna, Vienna, Austria
| | - Hanns-Ulrich Marschall
- Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Fritz Wrba
- Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria
| | - Makoto M Taketo
- Division of Experimental Therapeutics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Gerda Egger
- Clinical Institute of Pathology, Medical University of Vienna, Vienna, Austria
| | - Michael Trauner
- Hans Popper Laboratory for Molecular Hepatology, Department of Internal Medicine, Medical University of Vienna, Vienna, Austria
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13
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Sklavos A, Poutahidis T, Giakoustidis A, Makedou K, Angelopoulou K, Hardas A, Andreani P, Zacharioudaki A, Saridis G, Goulopoulos T, Tsarea K, Karamperi M, Papadopoulos V, Papanikolaou V, Papalois A, Iliadis S, Mudan S, Azoulay D, Giakoustidis D. Effects of Wnt-1 blockade in DEN-induced hepatocellular adenomas of mice. Oncol Lett 2017; 15:1211-1219. [PMID: 29399175 DOI: 10.3892/ol.2017.7427] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 09/01/2017] [Indexed: 12/19/2022] Open
Abstract
Recent evidence has suggested that downregulation of the Wnt/β-catenin signaling pathway may contribute to the development and growth of HCC. Consequently, elements of this pathway have begun to emerge as potential targets for improving outcomes of anti-HCC. Thus, the present study sought to examine the effects of Wnt-1 blockade using the classical diethylnitrosamine (DEN)-induced chemical carcinogenesis mouse model of HCC. The depletion of Wnt-1 using neutralizing antisera was done for ten consecutive days at the age of 9 months and mice were examined for the following 20 days. At that time, DEN-treated mice had multiple variably-sized hepatic cell adenomas. Anti-Wnt-1 was particularly potent in suppressing the expression of critical elements of the Wnt/β-catenin signaling pathway, such as β-catenin and Frizzled-1 receptor, however, not Dickkopf-related protein 1. This effect co-existed with the suppression of Cyclin D1, FOXM1, NF-κΒ and c-Jun commensurate with proliferation and apoptosis blockade in hepatocellular adenomas, and reduced Bcl-2 and c-Met in the serum of mice. Nonetheless, tumor size and multiplicity were found to be unaffected, suggesting that apoptosis may be equally important to proliferation in the context of counteracting DEN induced hepatocellular adenomas of mice.
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Affiliation(s)
- Argyrios Sklavos
- Division of Transplant Surgery, Department of Surgery, School of Medicine, Faculty of Health Sciences, Aristotle University and Hippokration General Hospital, Thessaloniki 54642, Greece
| | - Theofilos Poutahidis
- Laboratory of Pathology, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | | | - Kali Makedou
- Laboratory of Biochemistry, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Katerina Angelopoulou
- Laboratory of Biochemistry and Toxicology, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Alexander Hardas
- Laboratory of Pathology, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Paola Andreani
- Service de Chirurgie Digestive et Hépatobiliaire, Hôpital Henri Mondor, Assistance Publique-Hôpitaux de Paris-Université Paris-Est, Créteil 94000, France
| | | | - George Saridis
- Laboratory of Pathology, School of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Thomas Goulopoulos
- Division of Transplant Surgery, Department of Surgery, School of Medicine, Faculty of Health Sciences, Aristotle University and Hippokration General Hospital, Thessaloniki 54642, Greece
| | - Kalliopi Tsarea
- Experimental and Research Center ELPEN Pharmaceuticals, Athens 19009, Greece
| | - Maria Karamperi
- Experimental and Research Center ELPEN Pharmaceuticals, Athens 19009, Greece
| | - Vassilios Papadopoulos
- Propedeutic Division of Surgery, Department of Surgery School of Medicine, Faculty of Health Sciences, Aristotle University and AHEPA University Hospital, Thessaloniki 54124, Greece
| | - Vassilios Papanikolaou
- Division of Transplant Surgery, Department of Surgery, School of Medicine, Faculty of Health Sciences, Aristotle University and Hippokration General Hospital, Thessaloniki 54642, Greece
| | - Apostolos Papalois
- Experimental and Research Center ELPEN Pharmaceuticals, Athens 19009, Greece
| | - Stavros Iliadis
- Laboratory of Biochemistry, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Satvinder Mudan
- Academic Department of Surgery, The Royal Marsden Hospital, London SW3 6JJ, UK
| | - Daniel Azoulay
- Service de Chirurgie Digestive et Hépatobiliaire, Hôpital Henri Mondor, Assistance Publique-Hôpitaux de Paris-Université Paris-Est, Créteil 94000, France
| | - Dimitrios Giakoustidis
- Division of Transplant Surgery, Department of Surgery, School of Medicine, Faculty of Health Sciences, Aristotle University and Hippokration General Hospital, Thessaloniki 54642, Greece
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14
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Kazantseva YA, Pustylnyak YA, Pustylnyak VO. Role of Nuclear Constitutive Androstane Receptor in Regulation of Hepatocyte Proliferation and Hepatocarcinogenesis. BIOCHEMISTRY (MOSCOW) 2017; 81:338-47. [PMID: 27293091 DOI: 10.1134/s0006297916040040] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Activation of the constitutive androstane receptor (CAR) in hepatocytes occurs as a body adaptation in response to a number of external influences, and its functional activity is primarily related to induction of enzymes detoxifying xenobiotics. However, special attention was recently given to CAR due to the fact that its key role becomes unveiled in various physiological and pathophysiological processes occurring in the liver: gluconeogenesis, metabolism of fatty acids and bilirubin, hormonal regulation, proliferation of hepatocytes, and hepatocarcinogenesis. Here we review the main pathways and mechanisms that elevate hepatocyte proliferative activity related to CAR and whose disturbance may be a pivotal factor in hepatocarcinogenesis.
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Affiliation(s)
- Y A Kazantseva
- Institute of Molecular Biology and Biophysics, Novosibirsk, 630117, Russia
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15
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Zavattari P, Perra A, Menegon S, Kowalik MA, Petrelli A, Angioni MM, Follenzi A, Quagliata L, Ledda-Columbano GM, Terracciano L, Giordano S, Columbano A. Nrf2, but not β-catenin, mutation represents an early event in rat hepatocarcinogenesis. Hepatology 2015; 62:851-62. [PMID: 25783764 DOI: 10.1002/hep.27790] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 03/16/2015] [Indexed: 12/24/2022]
Abstract
UNLABELLED Hepatocellular carcinoma (HCC) develops through a multistage process, but the nature of the molecular changes associated with the different steps, the very early ones in particular, is largely unknown. Recently, dysregulation of the NRF2/KEAP1 pathway and mutations of these genes have been observed in experimental and human tumors, suggesting their possible role in cancer development. To assess whether Nrf2/Keap1 mutations are early or late events in HCC development, we investigated their frequency in the rat Resistant Hepatocyte model, consisting of the administration of diethylnitrosamine followed by a brief exposure to 2-acetylaminofluorene. This model enables the dissection of all stages of hepatocarcinogenesis. We found that Nrf2/Keap1 mutations were present in 71% of early preneoplastic lesions and in 78.6% and 59.3% of early and advanced HCCs, respectively. Mutations of Nrf2 were more frequent, missense, and located in the Nrf2-Keap1 binding region. Mutations of Keap1 occurred at a much lower frequency in both preneoplastic lesions and HCCs and were mutually exclusive with those of Nrf2. Functional in vitro and in vivo studies showed that Nrf2 silencing inhibited the ability of tumorigenic rat cells to grow in soft agar and to form tumors. Unlike Nrf2 mutations, those of Ctnnb1, which are frequent in human HCC, were a later event as they appeared only in fully advanced HCCs (18.5%). CONCLUSION In the Resistant Hepatocyte model of hepatocarcinogenesis the onset of Nrf2 mutations is a very early event, likely essential for the clonal expansion of preneoplastic hepatocytes to HCC, while Ctnnb1 mutations occur only at very late stages. Moreover, functional experiments demonstrate that Nrf2 is an oncogene critical for HCC progression and development.
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Affiliation(s)
- Patrizia Zavattari
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - Andrea Perra
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - Silvia Menegon
- University of Torino School of Medicine, Candiolo Cancer Institute-FPO, IRCCS Candiolo, Torino, Italy
| | - Marta Anna Kowalik
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - Annalisa Petrelli
- University of Torino School of Medicine, Candiolo Cancer Institute-FPO, IRCCS Candiolo, Torino, Italy
| | | | - Antonia Follenzi
- Department of Health Sciences, University of Piemonte Orientale, Novara, Italy
| | - Luca Quagliata
- Institute of Pathology, University Hospital, Basel, Switzerland
| | | | | | - Silvia Giordano
- University of Torino School of Medicine, Candiolo Cancer Institute-FPO, IRCCS Candiolo, Torino, Italy
| | - Amedeo Columbano
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
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16
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Zhang N, Wang L, Chai ZT, Zhu ZM, Zhu XD, Ma DN, Zhang QB, Zhao YM, Wang M, Ao JY, Ren ZG, Gao DM, Sun HC, Tang ZY. Incomplete radiofrequency ablation enhances invasiveness and metastasis of residual cancer of hepatocellular carcinoma cell HCCLM3 via activating β-catenin signaling. PLoS One 2014; 9:e115949. [PMID: 25542041 PMCID: PMC4277411 DOI: 10.1371/journal.pone.0115949] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 11/27/2014] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Radiofrequency ablation (RFA) is one of the curative therapies for hepatocellular carcinoma (HCC), however, accelerated progression of residual HCC after incomplete RFA has been reported more frequently. The underlying molecular mechanism of this phenomenon remains to be elucidated. In this study, we used an incomplete RFA orthotopic HCC nude mouse model to study the invasive and metastatic potential of residual cancer as well as the correlated mechanism. METHODS The incomplete RFA orthotopic nude mouse models were established using high metastatic potential HCC cell line HCCLM3 and low metastatic potential HCC cell line HepG2, respectively. The changes in cellular morphology, motility, metastasis and epithelial-mesenchymal transition (EMT), and HCC cell molecular markers after in vitro and in vivo incomplete RFA intervention were observed. RESULTS Pulmonary and intraperitoneal metastasis were observed in an in vivo study. The underlying pro-invasive mechanism of incomplete RFA appeared to be associated with promoting EMT, including down-regulation of E-cadherin and up-regulation of N-cadherin and vimentin. These results were in accordance with the in vitro response of HCC cells to heat intervention. Further studies demonstrated that β-catenin was a pivotal factor during this course and blocking β-catenin reduced metastasis and EMT phenotype changes in heat-treated HCCLM3 cells in vitro. CONCLUSION Incomplete RFA enhanced the invasive and metastatic potential of residual cancer, accompanying with EMT-like phenotype changes by activating β-catenin signaling in HCCLM3 cells.
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Affiliation(s)
- Ning Zhang
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory for Carcinogenesis and Cancer Invasion, The Chinese Ministry of Education, Shanghai, P. R. China
| | - Lu Wang
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory for Carcinogenesis and Cancer Invasion, The Chinese Ministry of Education, Shanghai, P. R. China
| | - Zong-Tao Chai
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory for Carcinogenesis and Cancer Invasion, The Chinese Ministry of Education, Shanghai, P. R. China
| | - Zi-Man Zhu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Chinese PLA General Hospital, Beijing, P. R. China
| | - Xiao-Dong Zhu
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory for Carcinogenesis and Cancer Invasion, The Chinese Ministry of Education, Shanghai, P. R. China
| | - De-Ning Ma
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory for Carcinogenesis and Cancer Invasion, The Chinese Ministry of Education, Shanghai, P. R. China
| | - Qiang-Bo Zhang
- Department of General Surgery, Qilu Hospital, Shandong University, Jinan, P. R. China
| | - Yi-Ming Zhao
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory for Carcinogenesis and Cancer Invasion, The Chinese Ministry of Education, Shanghai, P. R. China
| | - Miao Wang
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory for Carcinogenesis and Cancer Invasion, The Chinese Ministry of Education, Shanghai, P. R. China
| | - Jian-Yang Ao
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory for Carcinogenesis and Cancer Invasion, The Chinese Ministry of Education, Shanghai, P. R. China
| | - Zheng-Gang Ren
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory for Carcinogenesis and Cancer Invasion, The Chinese Ministry of Education, Shanghai, P. R. China
| | - Dong-Mei Gao
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory for Carcinogenesis and Cancer Invasion, The Chinese Ministry of Education, Shanghai, P. R. China
| | - Hui-Chuan Sun
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory for Carcinogenesis and Cancer Invasion, The Chinese Ministry of Education, Shanghai, P. R. China
| | - Zhao-You Tang
- Liver Cancer Institute and Zhongshan Hospital, Fudan University, Key Laboratory for Carcinogenesis and Cancer Invasion, The Chinese Ministry of Education, Shanghai, P. R. China
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17
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Perra A, Kowalik MA, Ghiso E, Ledda-Columbano GM, Di Tommaso L, Angioni MM, Raschioni C, Testore E, Roncalli M, Giordano S, Columbano A. YAP activation is an early event and a potential therapeutic target in liver cancer development. J Hepatol 2014; 61:1088-96. [PMID: 25010260 DOI: 10.1016/j.jhep.2014.06.033] [Citation(s) in RCA: 173] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Revised: 06/12/2014] [Accepted: 06/27/2014] [Indexed: 01/01/2023]
Abstract
BACKGROUND & AIMS Although the growth suppressing Hippo pathway has been implicated in hepatocellular carcinoma (HCC) pathogenesis, it is unknown at which stage of hepatocarcinogenesis its dysregulation occurs. We investigated in rat and human preneoplastic lesions whether overexpression of the transcriptional co-activator Yes-associated protein (YAP) is an early event. METHODS The experimental model used is the resistant-hepatocyte (R-H) rat model. Gene expression was determined by qRT-PCR or immunohistochemistry. Forward genetic experiments were performed in human HCC cells and in murine oval cells. RESULTS All foci of preneoplastic hepatocytes, generated in rats 4weeks after diethylnitrosamine (DENA) treatment, displayed YAP accumulation. This was associated with down-regulation of the β-TRCP ligase, known to mediate YAP degradation, and of microRNA-375, targeting YAP. YAP accumulation was paralleled by the up-regulation of its target genes. Increased YAP expression was also observed in human early dysplastic nodules and adenomas. Animal treatment with verteporfin (VP), which disrupts the formation of the YAP-TEAD complex, significantly reduced preneoplastic foci and oval cell proliferation. In vitro experiments confirmed that VP-mediated YAP inhibition impaired cell growth in HCC and oval cells; notably, oval cell transduction with wild type or active YAP conferred tumorigenic properties in vitro and in vivo. CONCLUSIONS These results suggest that (i) YAP overexpression is an early event in rat and human liver tumourigenesis; (ii) it is critical for the clonal expansion of carcinogen-initiated hepatocytes and oval cells, and (iii) VP-induced disruption of the YAP-TEAD interaction may provide an important approach for the treatment of YAP-overexpressing cancers.
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Affiliation(s)
- Andrea Perra
- Department of Biomedical Sciences, Unit of Oncology and Molecular Pathology, University of Cagliari, Cagliari, Italy
| | - Marta Anna Kowalik
- Department of Biomedical Sciences, Unit of Oncology and Molecular Pathology, University of Cagliari, Cagliari, Italy
| | - Elena Ghiso
- Department of Oncology, University of Torino School of Medicine, Candiolo Cancer Institute - FPO, IRCCS, 10060 Candiolo (Torino), Italy
| | | | - Luca Di Tommaso
- University of Milano and Humanitas Clinical and Research Center, Rozzano, Milano, Italy
| | - Maria Maddalena Angioni
- Department of Biomedical Sciences, Unit of Oncology and Molecular Pathology, University of Cagliari, Cagliari, Italy
| | - Carlotta Raschioni
- University of Milano and Humanitas Clinical and Research Center, Rozzano, Milano, Italy
| | - Elena Testore
- Department of Oncology, University of Torino School of Medicine, Candiolo Cancer Institute - FPO, IRCCS, 10060 Candiolo (Torino), Italy
| | - Massimo Roncalli
- University of Milano and Humanitas Clinical and Research Center, Rozzano, Milano, Italy
| | - Silvia Giordano
- Department of Oncology, University of Torino School of Medicine, Candiolo Cancer Institute - FPO, IRCCS, 10060 Candiolo (Torino), Italy.
| | - Amedeo Columbano
- Department of Biomedical Sciences, Unit of Oncology and Molecular Pathology, University of Cagliari, Cagliari, Italy.
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Genetic ablation of β-catenin inhibits the proliferative phenotype of mouse liver adenomas. Br J Cancer 2014; 111:132-8. [PMID: 24874479 PMCID: PMC4090738 DOI: 10.1038/bjc.2014.275] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 04/10/2014] [Accepted: 04/25/2014] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Aberrant activation of Wnt/β-catenin has been implicated in various cancer-related processes, for example, proliferation or tumour cell survival. However, the exact mechanism by which β-catenin provides liver tumour cells with a selective advantage is still unclear. This study was aimed to analyse growth behaviour and survival of β-catenin-driven mouse liver tumours after β-catenin ablation. METHODS Transgenic mice with a controllable hepatocyte-specific knockout of Ctnnb1 (encoding β-catenin) were generated and liver tumours were induced by means of a N-nitrosodiethylamine/phenobarbital tumour initiation/promotion protocol, which leads to the outgrowth of hepatocellular tumours with activated β-catenin. Cre recombinase was activated and the effects of the knockout in the tumours were studied. RESULTS Activation of Cre recombinase led to the knockout of Ctnnb1 in a fraction of tumour cells, thus resulting in the formation of two different tumour cell subpopulations, with or without β-catenin. Comparative analysis of the two subpopulations revealed that cell proliferation was significantly decreased in Ctnnb1-deleted hepatoma cells, compared with the corresponding non-deleted cell population, whereas no increased rate of apoptosis after knockout of Ctnnb1 was observed. CONCLUSIONS β-catenin-dependent signalling is an important regulator of hepatoma cell growth in mice, but not a crucial factor in the regulation of tumour survival.
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Chappell G, Kutanzi K, Uehara T, Tryndyak V, Hong HH, Hoenerhoff M, Beland FA, Rusyn I, Pogribny IP. Genetic and epigenetic changes in fibrosis-associated hepatocarcinogenesis in mice. Int J Cancer 2013; 134:2778-88. [PMID: 24242335 DOI: 10.1002/ijc.28610] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2013] [Accepted: 10/24/2013] [Indexed: 12/15/2022]
Abstract
Hepatocellular carcinoma (HCC) is one of the most prevalent cancers and is rising in incidence worldwide. The molecular mechanisms leading to the development of HCC are complex and include both genetic and epigenetic events. To determine the relative contribution of these alterations in liver tumorigenesis, we evaluated epigenetic modifications at both global and gene specific levels, as well as the mutational profile of genes commonly altered in liver tumors. A mouse model of fibrosis-associated liver cancer that was designed to emulate cirrhotic liver, a prevailing disease state observed in most humans with HCC, was used. Tumor and nontumor liver samples from B6C3F1 mice treated with N-nitrosodiethylamine (DEN; a single ip injection of 1 mg/kg at 14 days of age) and carbon tetrachloride (CCl4; 0.2 ml/kg, 2 times/week ip starting at 8 weeks of age for 14 weeks), as well as corresponding vehicle control animals, were analyzed for genetic and epigenetic alterations. H-ras, Ctnnb1 and Hnf1α genes were not mutated in tumors in mice treated with DEN+CCl4 . In contrast, the increased tumor incidence in mice treated with DEN+CCl4 was associated with marked epigenetic changes in liver tumors and nontumor liver tissue, including demethylation of genomic DNA and repetitive elements, a decrease in histone 3 lysine 9 trimethylation (H3K9me3) and promoter hypermethylation and functional downregulation of Riz1, a histone lysine methyltransferase tumor suppressor gene. Additionally, the reduction in H3K9me3 was accompanied by increased expression of long interspersed nucleotide elements 1 and short interspersed nucleotide elements B2, which is an indication of genomic instability. In summary, our results suggest that epigenetic events, rather than mutations in known cancer-related genes, play a prominent role in increased incidence of liver tumors in this mouse model of fibrosis-associated liver cancer.
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Affiliation(s)
- Grace Chappell
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC
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20
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Hoenerhoff MJ, Pandiri AR, Snyder SA, Hong HHL, Ton TV, Peddada S, Shockley K, Witt K, Chan P, Rider C, Kooistra L, Nyska A, Sills RC. Hepatocellular carcinomas in B6C3F1 mice treated with Ginkgo biloba extract for two years differ from spontaneous liver tumors in cancer gene mutations and genomic pathways. Toxicol Pathol 2013; 41:826-41. [PMID: 23262642 PMCID: PMC4799723 DOI: 10.1177/0192623312467520] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Ginkgo biloba leaf extract (GBE) has been used for centuries in traditional Chinese medicine and today is used as an herbal supplement touted for improving neural function and for its antioxidant and anticancer effects. Herbal supplements have the potential for consumption over extended periods of time, with a general lack of sufficient data on long-term carcinogenicity risk. Exposure of B6C3F1 mice to GBE in the 2-year National Toxicology Program carcinogenicity bioassay resulted in a dose-dependent increase in hepatocellular tumors, including hepatocellular carcinoma (HCC). We show that the mechanism of hepatocarcinogenesis in GBE exposed animals is complex, involving alterations in H-ras and Ctnnb1 mutation spectra, WNT pathway dysregulation, and significantly altered gene expression associated with oncogenesis, HCC development, and chronic xenobiotic and oxidative stress compared to spontaneous HCC. This study provides a molecular context for the genetic changes associated with hepatocarcinogenesis in GBE exposed mice and illustrates the marked differences between these tumors and those arising spontaneously in the B6C3F1 mouse. The molecular changes observed in HCC from GBE-treated animals may be of relevance to those seen in human HCC and other types of cancer, and provide important data on potential mechanisms of GBE hepatocarcinogenesis.
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Affiliation(s)
- Mark J Hoenerhoff
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences and National Toxicology Program, Research Triangle Park, NC 27519, USA.
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21
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Rignall B, Grote K, Gavrilov A, Weimer M, Kopp-Schneider A, Krause E, Appel KE, Buchmann A, Robertson LW, Lehmler HJ, Kania-Korwel I, Chahoud I, Schwarz M. Biological and tumor-promoting effects of dioxin-like and non-dioxin-like polychlorinated biphenyls in mouse liver after single or combined treatment. Toxicol Sci 2013; 133:29-41. [PMID: 23457121 PMCID: PMC3627557 DOI: 10.1093/toxsci/kft034] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 02/21/2013] [Indexed: 11/13/2022] Open
Abstract
To assess the impact of a mixture containing dioxin-like and non-dioxin-like polychlorinated biphenyls (PCBs), male mice were initiated with N-nitroso-diethylamine and subsequently treated with PCB126, an Ah-Receptor agonist, and PCB153, acting via activation of the constitutive androstane receptor. The two congeners were given at two dose levels: the low dose was adjusted to induce ~150-fold increases in cytochrome P450 (Cyp)1a1 (PCB126) and Cyp2b10 mRNAs (PCB153), and the high dose was chosen as twice the low dose. To keep the liver PCB levels constant, mice were given initial loading doses followed by weekly maintenance doses calculated on the basis of the PCBs' half-lives. Mice were treated with the individual congeners (low and high dose) or with a mixture consisting of the low doses of the 2 PCBs. The following results were obtained: (1) the 2 PCBs produced dose-dependent increases in Cyp1a1 and Cyp2b10 mRNA, protein, and activity when given individually; (2) combined treatment caused more than additive effects on Cyp1a1 mRNA expression, protein level, and ethoxyresurofin activity; (3) changes in the levels of several proteins were detected by proteome analysis in livers of PCB-treated mice; (4) besides these biological responses, the individual PCBs caused no significant increase in the number of glucose-6-phospatase (G6Pase)-deficient neoplastic lesions in liver, whereas a moderate significant effect occurred in the combination group. These results suggest weak but significant response-additive effects of the 2 PCBs when given in combination. They also suggest that the Cyp biomarkers tend to overestimate the carcinogenic response produced by the PCBs in mouse liver.
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Affiliation(s)
- Benjamin Rignall
- *Department of Toxicology, University of Tübingen, 72074 Tuebingen, Germany
| | - Konstanze Grote
- †Department of Experimental Medicine, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Alina Gavrilov
- *Department of Toxicology, University of Tübingen, 72074 Tuebingen, Germany
| | - Marc Weimer
- ‡German Cancer Research Center, Central Unit of Biostatistics, 69120 Heidelberg, Germany
| | - Annette Kopp-Schneider
- ‡German Cancer Research Center, Central Unit of Biostatistics, 69120 Heidelberg, Germany
| | - Eberhard Krause
- §Leibniz Institute for Molecular Pharmacology (FMP), 13125 Berlin, Germany
| | - Klaus E. Appel
- ¶Federal Institute for Risk Assessment, Unit of Food Toxicology, 14195 Berlin, Germany
| | - Albrecht Buchmann
- *Department of Toxicology, University of Tübingen, 72074 Tuebingen, Germany
| | - Larry W. Robertson
- ||Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa; and
| | - Hans-Joachim Lehmler
- ||Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa; and
| | - Izabela Kania-Korwel
- ||Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City, Iowa; and
| | - Ibrahim Chahoud
- |||Institute of Clinical Pharmacology and Toxicology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Schwarz
- *Department of Toxicology, University of Tübingen, 72074 Tuebingen, Germany
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Herrmann K, Schumacher F, Engst W, Appel KE, Klein K, Zanger UM, Glatt H. Abundance of DNA adducts of methyleugenol, a rodent hepatocarcinogen, in human liver samples. Carcinogenesis 2013; 34:1025-30. [DOI: 10.1093/carcin/bgt013] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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23
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Tsukamoto H, Zhu NL, Wang J, Asahina K, Machida K. Morphogens and hepatic stellate cell fate regulation in chronic liver disease. J Gastroenterol Hepatol 2012; 27 Suppl 2:94-8. [PMID: 22320925 PMCID: PMC3337168 DOI: 10.1111/j.1440-1746.2011.07022.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hepatic stellate cells (HSC) are the liver mesenchymal cell type which responds to hepatocellular damage and participates in wound healing. Although HSC myofibroblastic trans-differentiation (activation) is implicated in excessive extracellular matrix deposition, molecular understanding of this phenotypic switch from the viewpoint of cell fate regulation is limited. Recent studies demonstrate the roles of anti-adipogenic morphogens (Wnt, Necdin, Shh) in epigenetic repression of the HSC differentiation gene Pparγ as a causal event in HSC activation. These morphogens have positive cross-interactions which converge to epigenetic repression of Pparγ involving the methyl-CpG binding protein MeCP2. However, these morphogens expressed by activated HSC may also participate in cross-talk between HSC and hepatoblasts/hepatocytes to support liver regeneration, and their aberrant regulation may contribute to liver tumorigenesis. Implications of HSC-derived morphogens in these possibilities are discussed.
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Affiliation(s)
- Hidekazu Tsukamoto
- Southern California Research Center for ALPD and Cirrhosis, University of Southern California Keck School of Medicine, Los Angeles, CA,Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, CA,Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Nian-Ling Zhu
- Southern California Research Center for ALPD and Cirrhosis, University of Southern California Keck School of Medicine, Los Angeles, CA,Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, CA
| | - Jiaohong Wang
- Southern California Research Center for ALPD and Cirrhosis, University of Southern California Keck School of Medicine, Los Angeles, CA,Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, CA
| | - Kinji Asahina
- Southern California Research Center for ALPD and Cirrhosis, University of Southern California Keck School of Medicine, Los Angeles, CA,Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, CA
| | - Keigo Machida
- Southern California Research Center for ALPD and Cirrhosis, University of Southern California Keck School of Medicine, Los Angeles, CA,Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Los Angeles, CA
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24
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Schreiber S, Rignall B, Braeuning A, Marx-Stoelting P, Ott T, Buchmann A, Hammad S, Hengstler JG, Schwarz M, Köhle C. Phenotype of single hepatocytes expressing an activated version of β-catenin in liver of transgenic mice. J Mol Histol 2011; 42:393-400. [DOI: 10.1007/s10735-011-9342-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Accepted: 07/23/2011] [Indexed: 01/28/2023]
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25
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Stein TJ, Jochem A, Holmes KE, Sandgren EP. Effect of mutant β-catenin on liver growth homeostasis and hepatocarcinogenesis in transgenic mice. Liver Int 2011; 31:303-12. [PMID: 21281430 PMCID: PMC3093768 DOI: 10.1111/j.1478-3231.2010.02430.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND Mutations in the Wnt signalling pathway molecule β-catenin are associated with liver cancer. AIMS Our aim was to confirm the effects of stabilized β-catenin on liver growth, identify whether those effects were reversible and cell autonomous or non-cell autonomous and to model β-catenin-induced liver cancer in mice. METHODS Using a liver-specific inducible promoter, we generated transgenic mice in which the expression of mutant β-catenin can be induced or repressed within hepatocytes in mice of different ages. RESULTS Similar to other models, the hepatic expression of mutant β-catenin in our model beginning in utero or induced in quiescent adult liver resulted in a two-fold liver enlargement and development of disease with a latency of 1-5 months, and mice displayed elevated blood ammonia and altered hepatic gene expression. Our model additionally allowed us to discover that molecular and phenotypic abnormalities were reversible following the inhibition of transgene expression. Hepatocyte transplant studies indicated that mutant β-catenin could not increase the growth of transgene-expressing foci in either growth-permissive or -restrictive hepatic environments, but still directly altered hepatocyte gene expression. Mice with continuous but focal transgene expression developed hepatic neoplasms after the age of 1 year. CONCLUSIONS Our findings indicate that hepatocyte gene expression is directly affected by mutant β-catenin in a cell autonomous manner. However, hepatomegaly associated with diffuse hepatocyte-specific expression of mutant β-catenin is secondary to liver functional alteration or non-cell autonomous. Both phenotypes are reversible. Nevertheless, some foci of transgene-expressing cells progressed to carcinoma, confirming the association of mutant β-catenin with liver cancer.
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Affiliation(s)
- Timothy J. Stein
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Adam Jochem
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Katie E. Holmes
- Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Eric P. Sandgren
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
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26
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Nejak-Bowen KN, Monga SPS. Beta-catenin signaling, liver regeneration and hepatocellular cancer: sorting the good from the bad. Semin Cancer Biol 2010; 21:44-58. [PMID: 21182948 DOI: 10.1016/j.semcancer.2010.12.010] [Citation(s) in RCA: 201] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 12/09/2010] [Accepted: 12/14/2010] [Indexed: 12/19/2022]
Abstract
Among the adult organs, liver is unique for its ability to regenerate. A concerted signaling cascade enables optimum initiation of the regeneration process following insults brought about by surgery or a toxicant. Additionally, there exists a cellular redundancy, whereby a transiently amplifying progenitor population appears and expands to ensure regeneration, when differentiated cells of the liver are unable to proliferate in both experimental and clinical scenarios. One such pathway of relevance in these phenomena is Wnt/β-catenin signaling, which is activated relatively early during regeneration mostly through post-translational modifications. Once activated, β-catenin signaling drives the expression of target genes that are critical for cell cycle progression and contribute to initiation of the regeneration process. The role and regulation of Wnt/β-catenin signaling is now documented in rats, mice, zebrafish and patients. More recently, a regenerative advantage of the livers in β-catenin overexpressing mice was reported, as was also the case after exogenous Wnt-1 delivery to the liver paving the way for assessing means to stimulate the pathway for therapeutics in liver failure. β-Catenin is also pertinent in hepatic oval cell activation and differentiation. However, aberrant activation of the Wnt/β-catenin signaling is reported in a significant subset of hepatocellular cancers (HCC). While many mechanisms of such activation have been reported, the most functional means of aberrant and sustained activation is through mutations in the β-catenin gene or in AXIN1/2, which encodes for a scaffolding protein critical for β-catenin degradation. Intriguingly, in experimental models hepatic overexpression of normal or mutant β-catenin is insufficient for tumorigenesis. In fact β-catenin loss promoted chemical carcinogenesis in the liver due to alternate mechanisms. Since most HCC occur in the backdrop of chronic hepatic injury, where hepatic regeneration is necessary for maintenance of liver function, but at the same time serves as the basis of dysplastic changes, this Promethean attribute exhibits a Jekyll and Hyde behavior that makes distinguishing good regeneration from bad regeneration essential for targeting selective molecular pathways as personalized medicine becomes a norm in clinical practice. Could β-catenin signaling be one such pathway that may be redundant in regeneration and indispensible in HCC in a subset of cases?
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Lahousse SA, Hoenerhoff M, Collins J, Ton TVT, Masinde T, Olson D, Rebolloso Y, Koujitani T, Tomer KB, Hong HHL, Bucher J, Sills RC. Gene expression and mutation assessment provide clues of genetic and epigenetic mechanisms in liver tumors of oxazepam-exposed mice. Vet Pathol 2010; 48:875-84. [PMID: 21147764 DOI: 10.1177/0300985810390019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Liver tumors from a previous National Toxicology Program study were examined using global gene expression and mutation analysis to define the mechanisms of carcinogenesis in mice exposed to oxazepam. Five hepatocellular adenomas and 5 hepatocellular carcinomas from male B6C3F1 mice exposed to 5000 ppm oxazepam and 6 histologically normal liver samples from control animals were examined. One of the major findings in the study was upregulation of the Wnt/β-catenin signaling pathway. Genes that activate β-catenin, such as Sox4, were upregulated, whereas genes that inhibit Wnt signaling, such as APC and Crebbp, were downregulated. In addition, liver tumors from oxazepam-exposed mice displayed β-catenin mutations and increased protein expression of glutamine synthetase, a downstream target in the Wnt signaling pathway. Another important finding in this study was the altered expression of oxidative stress-related genes, specifically increased expression of cytochrome p450 genes, including Cyp1a2 and Cyp2b10, and decreased expression of genes that protect against oxidative stress, such as Sod2 and Cat. Increased oxidative stress was confirmed by measuring isoprostane expression using mass spectrometry. Furthermore, global gene expression identified altered expression of genes that are associated with epigenetic mechanisms of cancer. There was decreased expression of genes that are hypermethylated in human liver cancer, including tumor suppressors APC and Pten. Oxazepam-induced tumors also exhibited decreased expression of genes involved in DNA methylation (Crebbp, Dnmt3b) and histone modification (Sirt1). These data suggest that formation of hepatocellular adenomas and carcinomas in oxazepam-exposed mice involves alteration of the Wnt signaling pathway, oxidative stress, and potential epigenetic alterations.
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Affiliation(s)
- S A Lahousse
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
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Parody JP, Alvarez ML, Quiroga AD, Ceballos MP, Frances DE, Pisani GB, Pellegrino JM, Carnovale CE, Carrillo MC. Attenuation of the Wnt/beta-catenin/TCF pathway by in vivo interferon-alpha2b (IFN-alpha2b) treatment in preneoplastic rat livers. Growth Factors 2010; 28:166-77. [PMID: 20109105 DOI: 10.3109/08977190903547863] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Wnt/beta-catenin/T cell factor (TCF) pathway is activated in several types of human cancers, promoting cell growth and proliferation. Forkhead box containing protein class O (FOXO) transcription factors compete with TCF for beta-catenin binding, particularly under cellular oxidative stress conditions. Contrary to beta-catenin/TCF, beta-catenin/FOXO promotes the transcription of genes involved in cell cycle arrest and apoptosis. We have previously demonstrated that in vivo interferon-alpha2b (IFN-alpha2b) administration induces apoptosis in preneoplastic livers, a mechanism mediated by reactive oxygen species (ROS) and transforming growth factor-beta(1) (TGF-beta(1)). This study was aimed to assess the status of the Wnt/beta-catenin/TCF pathway in a very early stage of rat hepatocarcinogenesis and to further evaluate the effects of in vivo IFN-alpha2b treatment on it. We demonstrated that the Wnt/beta-catenin/TCF pathway is activated in preneoplastic rat livers. More important, in vivo IFN-alpha2b treatment inhibits Wnt/beta-catenin/TCF pathway and promotes programed cell death possibly providing a link with FOXO pathway.
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Affiliation(s)
- Juan P Parody
- Instituto de Fisiología Experimental, Consejo Nacional de Investigaciones Científicas y T écnicas (CONICET), 2000 Rosario, Argentina
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Hoenerhoff MJ, Hong HH, Ton TV, Lahousse SA, Sills RC. A review of the molecular mechanisms of chemically induced neoplasia in rat and mouse models in National Toxicology Program bioassays and their relevance to human cancer. Toxicol Pathol 2009; 37:835-48. [PMID: 19846892 PMCID: PMC3524969 DOI: 10.1177/0192623309351726] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Tumor response in the B6C3F1 mouse, F344 rat, and other animal models following exposure to various compounds provides evidence that people exposed to these or similar compounds may be at risk for developing cancer. Although tumors in rodents and humans are often morphologically similar, underlying mechanisms of tumorigenesis are often unknown and may be different between the species. Therefore, the relevance of an animal tumor response to human health would be better determined if the molecular pathogenesis were understood. The underlying molecular mechanisms leading to carcinogenesis are complex and involve multiple genetic and epigenetic events and other factors. To address the molecular pathogenesis of environmental carcinogens, the authors examine rodent tumors (e.g., lung, colon, mammary gland, skin, brain, mesothelioma) for alterations in cancer genes and epigenetic events that are associated with human cancer. National Toxicology Program (NTP) studies have identified several genetic alterations in chemically induced rodent neoplasms that are important in human cancer. Identification of such alterations in rodent models of chemical carcinogenesis caused by exposure to environmental contaminants, occupational chemicals, and other compounds lends further support that they are of potential human health risk. These studies also emphasize the importance of molecular evaluation of chemically induced rodent tumors for providing greater public health significance for NTP evaluated compounds.
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Affiliation(s)
- Mark J Hoenerhoff
- Cellular and Molecular Pathology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27519, USA.
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30
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Nejak-Bowen KN, Zeng G, Tan X, Cieply B, Monga SP. Beta-catenin regulates vitamin C biosynthesis and cell survival in murine liver. J Biol Chem 2009; 284:28115-28127. [PMID: 19690176 PMCID: PMC2788862 DOI: 10.1074/jbc.m109.047258] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Indexed: 12/18/2022] Open
Abstract
Because the Wnt/beta-catenin pathway plays multiple roles in liver pathobiology, it is critical to identify gene targets that mediate such diverse effects. Here we report a novel role of beta-catenin in controlling ascorbic acid biosynthesis in murine liver through regulation of expression of regucalcin or senescence marker protein 30 and L-gulonolactone oxidase. Reverse transcription-PCR, Western blotting, and immunohistochemistry demonstrate decreased regucalcin expression in beta-catenin-null livers and greater expression in beta-catenin overexpressing transgenic livers, HepG2 hepatoma cells (contain constitutively active beta-catenin), regenerating livers, and in hepatocellular cancer tissues that exhibit beta-catenin activation. Interestingly, coprecipitation and immunofluorescence studies also demonstrate an association of beta-catenin and regucalcin. Luciferase reporter and chromatin immunoprecipitation assays verified a functional TCF-4-binding site located between -163 and -157 (CTTTGCA) on the regucalcin promoter to be critical for regulation by beta-catenin. Significantly lower serum ascorbate levels were observed in beta-catenin knock-out mice secondary to decreased expression of regucalcin and also of L-gulonolactone oxidase, the penultimate and last (also rate-limiting) steps in the synthesis of ascorbic acid, respectively. These mice also show enhanced basal hepatocyte apoptosis. To test if ascorbate deficiency secondary to beta-catenin loss and regucalcin decrease was contributing to apoptosis, beta-catenin-null hepatocytes or regucalcin small interfering RNA-transfected HepG2 cells were cultured, which exhibited significant apoptosis that was alleviated by the addition of ascorbic acid. Thus, through regucalcin and L-gulonolactone oxidase expression, beta-catenin regulates vitamin C biosynthesis in murine liver, which in turn may be one of the mechanisms contributing to the role of beta-catenin in cell survival.
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Affiliation(s)
- Kari N Nejak-Bowen
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15216
| | - Gang Zeng
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15216
| | - Xinping Tan
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15216
| | - Benjamin Cieply
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15216
| | - Satdarshan P Monga
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15216; Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15216.
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Heindryckx F, Colle I, Van Vlierberghe H. Experimental mouse models for hepatocellular carcinoma research. Int J Exp Pathol 2009; 90:367-86. [PMID: 19659896 DOI: 10.1111/j.1365-2613.2009.00656.x] [Citation(s) in RCA: 276] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Every year almost 500,000 new patients are diagnosed with hepatocellular carcinoma (HCC), a primary malignancy of the liver that is associated with a poor prognosis. Numerous experimental models have been developed to define the pathogenesis of HCC and to test novel drug candidates. This review analyses several mouse models useful for HCC research and points out their advantages and weaknesses. Chemically induced HCC mice models mimic the injury-fibrosis-malignancy cycle by administration of a genotoxic compound alone or, if necessary, followed by a promoting agent. Xenograft models develop HCC by implanting hepatoma cell lines in mice, either ectopically or orthotopically; these models are suitable for drug screening, although extrapolation should be considered with caution as multiple cell lines must always be used. The hollow fibre assay offers a solution for limiting the number of test animals in xenograft research because of the ability for implanting multiple cell lines in one mouse. There is also a broad range of genetically modified mice engineered to investigate the pathophysiology of HCC. Transgenic mice expressing viral genes, oncogenes and/or growth factors allow the identification of pathways involved in hepatocarcinogenesis.
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Affiliation(s)
- Femke Heindryckx
- Department of Gastroenterology and Hepatology, Ghent University Hospital, 9000 Ghent, Belgium.
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32
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Maronpot RR, Zeiger E, McConnell EE, Kolenda-Roberts H, Wall H, Friedman MA. Induction of tunica vaginalis mesotheliomas in rats by xenobiotics. Crit Rev Toxicol 2009; 39:512-37. [DOI: 10.1080/10408440902969430] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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33
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2,2′,4,4′,5,5′-Hexachlorobiphenyl (PCB 153) induces degradation of adherens junction proteins and inhibits β-catenin-dependent transcription in liver epithelial cells. Toxicology 2009; 260:104-11. [DOI: 10.1016/j.tox.2009.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 03/17/2009] [Accepted: 03/18/2009] [Indexed: 12/16/2022]
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Hattis D, Chu M, Rahmioglu N, Goble R, Verma P, Hartman K, Kozlak M. A preliminary operational classification system for nonmutagenic modes of action for carcinogenesis. Crit Rev Toxicol 2009; 39:97-138. [PMID: 19009457 DOI: 10.1080/10408440802307467] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This article proposes a system of categories for nonmutagenic modes of action for carcinogenesis. The classification is of modes of action rather than individual carcinogens, because the same compound can affect carcinogenesis in more than one way. Basically, we categorize modes of action as: (1) co-initiation (facilitating the original mutagenic changes in stem and progenitor cells that start the cancer process) (e.g. induction of activating enzymes for other carcinogens); (2) promotion (enhancing the relative growth vs differentiation/death of initiated clones (e.g. inhibition of growth-suppressing cell-cell communication); (3) progression (enhancing the growth, malignancy, or spread of already developed tumors) (e.g. suppression of immune surveillance, hormonally mediated growth stimulation for tumors with appropriate receptors by estrogens); and (4) multiphase (e.g., "epigenetic" silencing of tumor suppressor genes). A priori, agents that act at relatively early stages in the process are expected to manifest greater relative susceptibility in early life, whereas agents that act via later stage modes will tend to show greater susceptibility for exposures later in life.
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Affiliation(s)
- D Hattis
- George Perkins Marsh Institute, Clark University, Worcester, Massachusetts, USA
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35
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Maronpot RR. Biological Basis of Differential Susceptibility to Hepatocarcinogenesis among Mouse Strains. J Toxicol Pathol 2009; 22:11-33. [PMID: 22271974 PMCID: PMC3246016 DOI: 10.1293/tox.22.11] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Accepted: 11/07/2008] [Indexed: 12/13/2022] Open
Abstract
There is a vast amount of literature related to mouse liver tumorigenesis generated over the past 60 years, not all of which has been captured here. The studies reported in this literature have generally been state of the art at the time they were carried out. A PubMed search on the topic "mouse liver tumors" covering the past 10 years yields over 7000 scientific papers. This review address several important topics related to the unresolved controversy regarding the relevance of mouse liver tumor responses observed in cancer bioassays. The inherent mouse strain differential sensitivities to hepatocarcinogenesis largely parallel the strain susceptibility to chemically induced liver neoplasia. The effects of phenobarbital and halogenated hydrocarbons in mouse hepatocarcinogenesis have been summarized because of recurring interest and numerous publications on these topics. No single simple paradigm fully explains differential mouse strain responses, which can vary more than 50-fold among inbred strains. In addition to inherent genetics, modifying factors including cell cycle balance, enzyme induction, DNA methylation, oncogenes and suppressor genes, diet, and intercellular communication influence susceptibility to spontaneous and induced mouse hepatocarcinogenesis. Comments are offered on the evaluation, interpretation, and relevance of mouse liver tumor responses in the context of cancer bioassays.
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Affiliation(s)
- Robert R Maronpot
- Maronpot Consulting, LLC, 1612 Medfield Road, Raleigh, NC 27607-4726, USA
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36
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López-Terrada D, Gunaratne PH, Adesina AM, Pulliam J, Hoang DM, Nguyen Y, Mistretta TA, Margolin J, Finegold MJ. Histologic subtypes of hepatoblastoma are characterized by differential canonical Wnt and Notch pathway activation in DLK+ precursors. Hum Pathol 2009; 40:783-94. [PMID: 19200579 DOI: 10.1016/j.humpath.2008.07.022] [Citation(s) in RCA: 223] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 06/28/2008] [Accepted: 07/31/2008] [Indexed: 12/28/2022]
Abstract
Hepatoblastoma is characterized by a diversity of differentiation patterns, some resembling stages of liver development, and occasionally associated with clinical behavior. Our hypothesis is that histologic microheterogeneity in hepatoblastoma correlates with molecular heterogeneity and reflects different stages of developmental arrest. We studied the activation status of the Wnt and Notch pathways and the differential expression of hepatocyte nuclear factor 4alpha, EGFR, and IGF2 genes, relevant to liver development and malignant transformation in histologic variants of hepatoblastoma. Eighty-seven percent of 32 hepatoblastoma cases studied carried CTNNB1 mutations within the ubiquitination domain. Large deletions were seen only in pure fetal cases, also characterized by CCND1 and GLUL (GS) overexpression. Hepatoblastomas with small-cell type appeared clearly distinct and were the only ones with negative GLUL expression. HES1 expression and HES1/AXIN2 used to measure Notch versus Wnt activation ratio were particularly elevated in pure fetal cases and were lowest in hepatoblastomas with small-cell component. Hepatocyte nuclear factor 4alpha was relatively elevated only in embryonal hepatoblastomas. DLK1, DKK, AXIN2, IGF2, and EGFR were increased in all subtypes. Our results support the hypothesis that hepatoblastoma microheterogeneity correlates with molecular heterogeneity. DLK1, a marker of bipotential oval cells, is consistently up-regulated in hepatoblastoma. Therefore, we speculate that hepatoblastomas may arise from a proliferating bipotential precursor. Wnt activation is prevalent in hepatoblastomas, most significantly in predominantly embryonal and mixed types, whereas Notch activation, needed for cholangiocytic differentiation at a more differentiated state, is highest in pure fetal hepatoblastomas. The relative Wnt versus Notch activation appears useful in stratifying different subtypes.
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Abstract
Hepatocellular carcinoma (HCC) is a major cause of cancer death worldwide. As in many other types of cancer, aberrant activation of the canonical Wnt/beta-catenin signaling pathway is an important contributor to tumorigenesis. In HCC this frequently occurs through mutations in the N-terminal region of beta-catenin that stabilize the protein and permit an elevated level of constitutive transcriptional activation by beta-catenin/TCF complexes. In this article we review the abundant evidence that Wnt/beta-catenin signaling contributes to liver carcinogenesis. We also discuss what is known about the roles of Wnt signaling in liver development, regeneration, and stem cell behavior, in an effort to understand the mechanisms by which activation of the canonical Wnt pathway promotes tumor formation in this organ. The Wnt/beta-catenin pathway presents itself as an attractive target for developing novel rational therapies for HCC, a disease for which few successful treatment strategies are currently available.
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Affiliation(s)
- Yutaka Takigawa
- Department of Cell & Developmental Biology, Weill Cornell Medical College, New York, NY10065, USA
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38
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Köhle C, Schwarz M, Bock KW. Promotion of hepatocarcinogenesis in humans and animal models. Arch Toxicol 2008; 82:623-31. [DOI: 10.1007/s00204-007-0273-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Accepted: 12/10/2007] [Indexed: 01/12/2023]
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39
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Saffroy R, Pham P, Reffas M, Takka M, Lemoine A, Debuire B. New perspectives and strategy research biomarkers for hepatocellular carcinoma. Clin Chem Lab Med 2008; 45:1169-79. [PMID: 17635075 DOI: 10.1515/cclm.2007.262] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. Cirrhosis caused by hepatitis B virus, hepatitis C virus or chronic alcohol intake is associated with major risk. Systematic screening for HCC of asymptomatic patients with cirrhosis is needed for earlier detection of small tumors requiring treatment (liver transplantation, surgical resection, percutaneous techniques). The recommended screening strategy among cirrhotic patients is based on regular liver ultrasonography associated with serum alpha-fetoprotein (AFP) assay. As the performance of AFP is not satisfactory, additional tumoral markers are proposed (des-gamma-carboxyprothrombin, glycosylated AFP-L3 fraction). Currently, diagnosis of HCC in cirrhotic patients includes non-invasive tests (imaging after contrast administration, AFP assay); diagnostic biopsy is performed when imaging is limited. After treatment, tumor recurrence is assessed by regular follow-up (AFP assay and imaging). Despite the lack of accurate markers, recent developments in genomic and proteomic approaches will allow the discovery of new biomarkers for primary tumors, as well as for recurrence. This review summarizes the current state of biomarkers for screening, diagnosis and follow-up of HCC, and highlights new perspectives in the field.
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Affiliation(s)
- Raphaël Saffroy
- Service de Biochimie, Biologie Moléculaire et Toxicologie, Hôpital Universitaire Paul Brousse, Université Paris-Sud, UMR-S602, Villejuif, INSERM, Villejuif, France.
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40
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Strathmann J, Paal K, Ittrich C, Krause E, Appel KE, Glauert HP, Buchmann A, Schwarz M. Proteome analysis of chemically induced mouse liver tumors with different genotype. Proteomics 2007; 7:3318-31. [PMID: 17722141 DOI: 10.1002/pmic.200600983] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mouse liver tumors frequently harbor mutations in Ha-ras, B-raf, or Ctnnb1 (encoding beta-catenin). We conducted a proteome analysis with protein extracts from normal mouse liver and from liver tumors which were induced by a single injection of N-nitrosodiethylamine (DEN) as initiator followed by multiple injections of two different polychlorinated biphenyls (PCBs) as tumor promoters, or corn oil as a control. Liver tumors were stratified into two classes: they were either mutated in Ctnnb1 and positive for the marker glutamine synthetase (GS(+)), or they lacked Ctnnb1 mutations and were therefore GS-negative (GS(-)). Proteome analysis by 2-DE and MS revealed 98 significantly deregulated proteins, 44 in GS(+) and 54 in GS(-) tumors. Twelve of these proteins showed expression changes in both tumor types, but only seven of them were deregulated in the same direction. Several of the identified enzymes could be assigned to fundamental metabolic or other cellular pathways with characteristically different alterations in GS(+) and GS(-) tumors such as ammonia and amino acid turnover, cellular energy supply, and calcium homeostasis. Our data suggest that GS(+) and GS(-) tumor cells show a completely different biology and use divergent evolutionary strategies to gain a selective advantage over normal hepatocytes.
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Affiliation(s)
- Julia Strathmann
- Department of Toxicology, University of Tübingen, Tübingen, Germany
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41
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Braeuning A, Menzel M, Kleinschnitz EM, Harada N, Tamai Y, Köhle C, Buchmann A, Schwarz M. Serum components and activated Ha-ras antagonize expression of perivenous marker genes stimulated by beta-catenin signaling in mouse hepatocytes. FEBS J 2007; 274:4766-77. [PMID: 17697114 DOI: 10.1111/j.1742-4658.2007.06002.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Hepatocytes of the periportal and perivenous zones of the liver lobule show marked differences in the contents and activities of many enzymes and other proteins. Previous studies from our and other groups have pointed towards an important role of beta-catenin-dependent signaling in the regulation of expression of genes encoding proteins with preferential perivenous localization, whereas, in contrast, signaling through Ras-dependent pathway(s) may induce a 'periportal' phenotype. We have now conducted a series of experiments to further investigate this hypothesis. In transgenic mice with scattered expression of an activated Ha-ras (Ha-ras(G12V)) mutant in liver, expression of the perivenous markers glutamine synthetase and two cytochrome P450 isoforms was completely abolished in those hepatocytes demonstrating constitutively activated extracellular signal-regulated kinase activity, even though they were located directly adjacent to central veins. Similarly, incubation of primary hepatocytes or hepatoma cells with increasing amounts of serum caused a concentration-dependent attenuation of expression of perivenous marker mRNAs, whereas the expression of periportal markers was increased. The inhibitory effect of high amounts of serum on the expression of perivenous markers was also observed if their expression was stimulated by activation of beta-catenin signaling, and comparable inhibitory effects were seen in cells stably transfected with a T-cell factor/lymphoid-enhancing factor-driven luciferase reporter. Epidermal growth factor could partly mimic serum effects in hepatoma cells, and its effect could be blocked by an inhibitor of extracellular signal-regulated kinase activity. These data suggest that activation of the Ras/mitogen-activated protein kinase (extracellular signal-regulated kinase) pathway favors periportal gene expression while simultaneously antagonizing a perivenous phenotype of hepatocytes.
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Affiliation(s)
- Albert Braeuning
- Institute of Pharmacology und Toxicology, Department of Toxicology, University of Tuebingen, Germany
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42
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Apte U, Zeng G, Muller P, Tan X, Micsenyi A, Cieply B, Dai C, Liu Y, Kaestner KH, Monga SPS. Activation of Wnt/beta-catenin pathway during hepatocyte growth factor-induced hepatomegaly in mice. Hepatology 2006; 44:992-1002. [PMID: 17006939 DOI: 10.1002/hep.21317] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Hepatocyte growth factor (HGF) and beta-catenin both play a crucial role in stimulating hepatocyte proliferation, but whether these 2 pathways cooperate in inducing hepatocyte proliferation is unclear. We have previously reported that beta-catenin forms a complex with c-Met (HGF receptor) that undergoes dissociation because of beta-catenin tyrosine phosphorylation on stimulation by HGF. It is also known that delivery of the human HGF gene cloned in a plasmid under a CMV promoter results in hepatomegaly in mice. In addition, recently characterized beta-catenin transgenic mice also showed hepatomegaly. The present study was based on the hypothesis that HGF-induced hepatomegaly is mediated, at least in part, by activation of the Wnt/beta-catenin pathway. Here we report that delivery of the human HGF gene delivery in mice led to hepatomegaly via beta-catenin activation in the liver in 1- and 4-week studies. The mechanisms of beta-catenin activation in the 1-week study included loss of c-Met-beta-catenin association as well as canonical beta-catenin activation, leading to its nuclear translocation. In the 4-week study, beta-catenin activation was observed via canonical mechanisms, whereas the c-Met-beta-catenin complex remained unchanged. In both studies there was an associated increase in the E-cadherin-beta-catenin association at the membrane. In addition, we generated liver-specific beta-catenin knockout mice, which demonstrated significantly smaller livers. HGF gene delivery failed to induce hepatomegaly in these beta-catenin conditionally null mice. In conclusion, beta-catenin- and HGF-mediated signaling pathways cooperate in hepatocyte proliferation, which may be crucial in liver development, regeneration following partial hepatectomy, and pathogenesis of hepatocellular carcinoma.
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Affiliation(s)
- Udayan Apte
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15216, USA
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43
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Strathmann J, Schwarz M, Tharappel JC, Glauert HP, Spear BT, Robertson LW, Appel KE, Buchmann A. PCB 153, a non-dioxin-like tumor promoter, selects for beta-catenin (Catnb)-mutated mouse liver tumors. Toxicol Sci 2006; 93:34-40. [PMID: 16782779 DOI: 10.1093/toxsci/kfl041] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Polychlorinated biphenyls (PCBs) are ubiquitous environmental toxicants which act as liver tumor promoters in rodents and can be classified as either dioxin-like or non-dioxin (phenobarbital [PB])-like inducers of cytochrome P-450. Since we have previously shown that tumor promotion by PB leads to clonal outgrowth of beta-catenin (Catnb)-mutated but not Ha-ras-mutated mouse liver tumors, we were interested to know whether the non-dioxin-like tumor promoter 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) shows the same selective pressure during tumor promotion. Male B6129SF2/J mice were given a single injection of N-nitrosodiethylamine (90 mg/kg body weight) at 9 weeks of age, followed by 39 weeks of treatment with PCB 153 (20 biweekly ip injections of 300 mumol/kg body weight) or corn oil as a control. Animals were killed 15 weeks after the last PCB 153 injection and liver tumors were identified by immunohistochemical staining of glutamine synthetase (GS) and analyzed for Catnb, Ha-ras, and B-raf mutations. Quantitative analyses revealed that GS-positive tumors were much larger and more frequent in livers from PCB 153-treated mice than in control animals, whereas GS-negative tumors were similar in both groups. Almost 90% (34/38) of all tumors from PCB 153-treated animals contained Catnb mutations, which compares to approximately 45% (17/37) of tumors in the control group. Ha-ras- and B-raf-mutated liver tumors were rare and not significantly different between treatment groups. These results clearly indicate that PCB 153 strongly selects for Catnb-mutated, GS-positive liver tumors, which is similar to the known action of PB, a prototypical tumor promoter in rodent liver.
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Affiliation(s)
- Julia Strathmann
- Department of Toxicology, University of Tuebingen, 72074 Tuebingen, Germany
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44
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Kushida M, Aiso S, Morimura K, Wei M, Wanibuchi H, Nagano K, Fukushima S. Absence of beta-catenin alteration in hepatic tumors induced by p-nitroanisole in Crj:BDF1 mice. Toxicol Pathol 2006; 34:237-42. [PMID: 16698720 DOI: 10.1080/01926230600695474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In the present study, beta-catenin localization in hepatocellular neoplasms and hepatoblastomas, induced by oral administration of p-Nitroanisole (pNA) in Crj:BDF1 for 2 years, was evaluated by immunohistochemistry along with genetic alterations in exon 2 of beta-catenin by the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) approach. Genomic DNA was isolated from paraffin sections of a total of 53 liver tumors. Immunohistochemical analysis revealed no abnormal accumulation of the beta-catenin protein in any of the cases. No mutations (0/13), 20% silent mutations (3/15) and 8% silent plus 12% functional mutations (2 + 3/25), not in the multiple phosphorylation sites of beta-catenin, were observed in hepatocellular adenomas, carcinomas and hepatoblastomas, respectively. The results indicate that beta-catenin does not play an important role in development of hepatic tumors induced by pNA in Crj:BDF1 mice.
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Affiliation(s)
- Masahiko Kushida
- Department of Pathology, Osaka City University Medical School, Abeno-ku, Osaka 545-8585, Japan
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45
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Alexia C, Fourmatgeat P, Delautier D, Groyer A. Insulin-like growth factor-I stimulates H4II rat hepatoma cell proliferation: Dominant role of PI-3′K/Akt signaling. Exp Cell Res 2006; 312:1142-52. [PMID: 16487514 DOI: 10.1016/j.yexcr.2006.01.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2004] [Revised: 11/23/2005] [Accepted: 01/10/2006] [Indexed: 01/26/2023]
Abstract
Although hepatocytes are the primary source of endocrine IGF-I and -II in mammals, their autocrine/paracrine role in the dysregulation of proliferation and apoptosis during hepatocarcinogenesis and in hepatocarcinomas (HCC) remains to be elucidated. Indeed, IGF-II and type-I IGF receptors are overexpressed in HCC cells, and IGF-I is synthesized in adjacent non-tumoral liver tissue. In the present study, we have investigated the effects of type-I IGF receptor signaling on H4II rat hepatoma cell proliferation, as estimated by 3H-thymidine incorporation into DNA. IGF-I stimulated the rate of DNA synthesis of serum-deprived H4II cells, stimulation being maximal 3 h after the onset of IGF-I treatment and remaining elevated until at least 6 h. The IGF-I-induced increase in DNA replication was abolished by LY294002 and only partially inhibited by PD98059, suggesting that phosphoinositol-3' kinase (PI-3'K) and to a lesser extent MEK/Erk signaling were involved. Furthermore, the 3- to 19-fold activation of the Erks in the presence of LY294002 suggested a down-regulation of the MEK/Erk cascade by PI-3'K signaling. Finally, the effect of IGF-I on DNA replication was almost completely abolished in clones of H4II cells expressing a dominant-negative form of Akt but was unaltered by rapamycin treatment of wild-type H4II cells. Altogether, these data support the notion that the stimulation of H4II rat hepatoma cell proliferation by IGF-I is especially dependent on Akt activation but independent on the Akt/mTOR signaling.
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Affiliation(s)
- Catherine Alexia
- Inserm U.481, Faculté de Médecine Xavier Bichat, 16, rue Henri Huchard, BP416, 75870 Paris Cedex 18, France
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46
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Plante I, Cyr DG, Charbonneau M. Involvement of the integrin-linked kinase pathway in hexachlorobenzene-induced gender-specific rat hepatocarcinogenesis. Toxicol Sci 2005; 88:346-57. [PMID: 16162845 DOI: 10.1093/toxsci/kfi323] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Overexpression of the integrin-linked kinase (ILK) pathway disrupts cell-cell interactions, an epigenetic event leading to epithelial cell transformation. Female rats exposed to hexachlorobenzene (HCB) for 5 consecutive days and sampled 45 days later show a decrease in liver gap junctional intercellular communication. We hypothesized that HCB also alters E-cadherin expression and that this alteration is mediated by the ILK pathway. Hepatic ILK levels were markedly increased in HCB-treated female rats. Cytoplasmic/membrane levels of protein kinase B (Akt), a target of ILK, and its phosphorylated active form were decreased in treated female rats. Flow cytometric analysis showed a concomitant increase in nuclear Akt levels. Both ILK and Akt can phosphorylate glycogen synthetase kinase-3beta (GSK3beta), rendering it inactive. Phosphorylated-GSK3beta levels were higher in treated females and resulted in a twofold decrease in the activity of GSK3beta. The inactivation of GSK3beta in HCB-treated female rats resulted in the nuclear translocation of beta-catenin, as demonstrated by both immunocytochemistry and flow cytometric analyses. Western blot analysis showed an 84% decrease in E-cadherin levels in HCB-treated rats as compared to controls, and this decrease was not mediated by Snail activation. Mimicking the activation of ILK with specific GSK3beta inhibitors resulted in downregulation of E-cadherin levels but had no effect on Cx32 expression in the MH(1)C(1) cells. Overall, these results indicate that hepatic E-cadherin is downregulated as a result of an overexpression of the ILK pathway. The concomitant HCB-induced downregulation of intercellular communication does not occur as a result of either E-cadherin downregulation or GSK3beta inactivation.
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Affiliation(s)
- Isabelle Plante
- INRS-Institut Armand-Frappier, Université du Québec, Pointe-Claire, Canada
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47
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Schwarz M, Appel KE. Carcinogenic risks of dioxin: Mechanistic considerations. Regul Toxicol Pharmacol 2005; 43:19-34. [PMID: 16054739 DOI: 10.1016/j.yrtph.2005.05.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Indexed: 12/01/2022]
Abstract
Dioxins and dioxin-like chemicals demonstrate high affinity binding to the aryl hydrocarbon receptor (AhR), a ligand activated transcription factor, which mediates most, if not all, of the toxic responses of these agents. Since dioxins are not directly genotoxic their carcinogenic effect is likely the result of their tumor promoting activity produced by activation of the AhR. For the purpose of risk assessment extrapolation from effects in the observable high dose range to background dietary exposure is necessary. In the present review, we discuss various aspects of low-dose-response of receptor-mediated processes in general, including threshold phenomena with regard to tumor promotion during multi-stage carcinogenesis. In this connection the reversibility of tumor promotion plays an important role but this may not be valid for dioxins due to their long half life. The relevance of cytochrome P 4501 A-induction as biomarker for prediction of carcinogenic effects of dioxins at low doses is considered. Dioxins may act in concert with endogenous ligands of the AhR, an effect which becomes particularly relevant at low toxicant concentrations. At present, however, the nature and role of these postulated ligands are unknown. Furthermore, it is unclear whether dioxins produce synergistic tumor promotional effects with non-dioxin-like chemicals to which humans are also exposed. Dioxins and, e.g., non-dioxin-like PCBs act through different receptors and there is, albeit yet limited, experimental evidence from experimental studies to suggest that they may act on different target cell populations within the same target organ. From the available data the existence of a (physiological) threshold of effects cannot be proven and may not even exist. For regulatory purposes the application of a so called "practical threshold" for the carcinogenic effect of dioxins is proposed. Further mechanistic studies should be conducted to get insight into the dose-response characteristics of relevant events of dioxin-like and non-dioxin-like agents and into the consequences of potential interactions between both group of compounds during carcinogenesis.
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Affiliation(s)
- Michael Schwarz
- Institute of Pharmacology and Toxicology, Department of Toxicology, University of Tübingen, Wilhelmstr. 56, 72074 Tübingen, Germany
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Elmileik H, Paterson AC, Kew MC. Beta-catenin mutations and expression, 249serine p53 tumor suppressor gene mutation, and hepatitis B virus infection in southern African Blacks with hepatocellular carcinoma. J Surg Oncol 2005; 91:258-63. [PMID: 16121349 DOI: 10.1002/jso.20304] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND AND OBJECTIVES To ascertain the prevalence of deregulating mutations of beta-catenin gene, and to correlate this with the occurrence of 249(serine) p53 gene mutation and hepatitis B virus infection in southern African Blacks with hepatocellular carcinoma. METHODS Paired cancer/non-cancerous liver tissues from 21 and cancer tissues alone from 20 Black Africans with hepatocellular carcinoma were studied. RT-PCR-SSCP and sequencing were used to detect mutations in exon 3 of the beta-catenin gene, and PCR, restriction endonuclease analysis, and sequencing to detect the p53 gene mutation. Immunostaining was used to identify beta-catenin protein expression in hepatocytes. RESULTS No mutations in exon 3 of the beta-catenin gene were found in tumor or non-tumorous tissues. Immunohistochemical staining showed beta-catenin protein expression in membranes and cytoplasm of hepatocytes but not in the nuclei. The 249serine p53 gene mutation was detected in 27.2% of the hepatocellular carcinoma tissues but not in non-cancerous tissues. No correlation was found between beta-catenin mutation and over-expression and 249serine p53 gene mutations or hepatitis B virus surface antigenemia. CONCLUSIONS Unlike hepatocellular carcinomas in China, Japan, and Europe, deregulating beta-catenin gene mutations do not appear to occur in southern African Blacks with this tumor and do not therefore interact with either the 249serine p53 gene mutation or hepatitis B virus infection in its pathogenesis.
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Affiliation(s)
- Hashim Elmileik
- MRC/University Molecular Hepatology Research Unit, Department of Medicine, University of the Witwatersrand, Johannesburg, South Africa
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Tan X, Apte U, Micsenyi A, Kotsagrelos E, Luo JH, Ranganathan S, Monga DK, Bell A, Michalopoulos GK, Monga SPS. Epidermal growth factor receptor: a novel target of the Wnt/beta-catenin pathway in liver. Gastroenterology 2005; 129:285-302. [PMID: 16012954 PMCID: PMC1821080 DOI: 10.1053/j.gastro.2005.04.013] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Wnt/beta-catenin activation is observed in normal liver development, regeneration, and liver cancer. Our aim was to elucidate the regulation and mechanism of this pathway in liver. METHODS We report the generation and characterization of liver-specific nonmutated beta-catenin-overexpressing transgenic mice. Transgenic livers were examined for their morphology and phenotype by histology, proliferation, apoptosis, and microarray analysis. RESULTS Transgenic livers displayed a significant increase in cytoplasmic, membranous, and nuclear beta-catenin in hepatocytes as compared with their wild-type littermates, which display a predominant membranous localization only. A 15%-20% increase in the liver weight-body weight ratio was evident in transgenic mice secondary to increased hepatocyte proliferation. Microarray analysis showed differential expression of approximately 400 genes in the transgenic livers. Epidermal growth factor receptor RNA and protein and increased levels of activated epidermal growth factor receptor and Stat3 were observed in the transgenic livers. Epidermal growth factor receptor promoter analysis showed a T-cell factor-binding site, and subsequent reporter assay confirmed epidermal growth factor receptor activation in response to Wnt-3A treatment that was abrogated by frizzled related protein 1, a known Wnt antagonist. Epidermal growth factor receptor inhibition successfully decreased liver size in transgenic mice. Next, 7 of 10 hepatoblastomas displayed simultaneous beta-catenin and epidermal growth factor receptor up-regulation, thus suggesting a strong relationship between these 2 proteins in tumors. CONCLUSIONS beta-Catenin transgenic mice show an in vivo hepatotrophic effect secondary to increased basal hepatocyte proliferation. Epidermal growth factor receptor seems to be a direct target of the pathway, and epidermal growth factor receptor activation might contribute toward some mitogenic effects of increased beta-catenin in liver: epidermal growth factor receptor inhibition might be useful in such states.
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Affiliation(s)
- Xinping Tan
- Department of Pathology, University of Pittsburgh, School of Medicine, Pennsylvania 15261, USA
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Malarkey DE, Parker JS, Turman CA, Scott AM, Paules RS, Collins J, Maronpot RR. Microarray data analysis of mouse neoplasia. Toxicol Pathol 2005; 33:127-35. [PMID: 15805064 DOI: 10.1080/01926230590888315] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Microarray gene expression analysis offers great promise to help us understand the molecular events of experimental carcinogenesis, but have such promises been fulfilled? Studies of gene expression profiles of rodent are being published and demonstrate that yes, indeed, gene array data is furthering our understanding of tumor biology. Recent studies have identified differentially expressed genes in rodent mammary, colon, lung, and liver tumors. Although relatively few genes on the rodent arrays have been fully characterized, information has been generated to better identify signatures of histologic type and grade, understand invasion and metastasis, identify candidate biomarkers of early development, identify gene networks in carcinogenesis, understand responses to therapy, and decifer overlap with molecular events in human cancers. Data from mouse lung, mammary gland, and liver tumor studies are reviewed as examples of how to approach and interpret gene array data. Methods of gene array data analysis were also applied for discovery of genes involved in the regression of mouse liver tumors induced by chlordane, a nongenotoxic murine hepatocarcinogen. Promises are beginning to be fulfilled and it is clear that pathologists and toxicologists, in collaboration with molecular biologists, bioinformatists,and other scientists are making great strides in the design, analysis, and interpretation of microarray data for cancer studies.
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Affiliation(s)
- David E Malarkey
- Laboratory of Experimental Pathology, Research Triangle Park, North Carolina 27709, USA.
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