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Klaunig JE, Cohen SM. Mode of action of dieldrin-induced liver tumors: application to human risk assessment. Crit Rev Toxicol 2024:1-25. [PMID: 39077834 DOI: 10.1080/10408444.2024.2377208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 07/31/2024]
Abstract
Dieldrin is an organochlorine insecticide that was widely used until 1970 when its use was banned because of its liver carcinogenicity in mice. Several long-term rodent bioassays have reported dieldrin to induce liver tumors in in several strains of mice, but not in rats. This article reviews the available information on dieldrin liver effects and performs an analysis of mode of action (MOA) and human relevance of these liver findings. Scientific evidence strongly supports a MOA based on CAR activation, leading to alterations in gene expression, which result in increased hepatocellular proliferation, clonal expansion leading to altered hepatic foci, and ultimately the formation of hepatocellular adenomas and carcinomas. Associative events include increased liver weight, centrilobular hypertrophy, increased expression of Cyp2b10 and its resulting increased enzymatic activity. Other associative events include alterations of intercellular gap junction communication and oxidative stress. Alternative MOAs are evaluated and shown not to be related to dieldrin administration. Weight of evidence shows that dieldrin is not DNA reactive, it is not mutagenic, and it is not genotoxic in general. Furthermore, activation of other pertinent nuclear receptors, including PXR, PPARα, AhR, and estrogen are not related to dieldrin-induced liver tumors nor is there liver cytotoxicity. In previous studies, rats, dogs, and non-human primates did not show increased cell proliferation or production of pre-neoplastic or neoplastic lesions following dieldrin treatment. Thus, the evidence strongly indicates that dieldrin-induced mouse liver tumors are due to CAR activation and are specific to the mouse, which are qualitatively not relevant to human hepatocarcinogenesis. Thus, there is no carcinogenic risk to humans. This conclusion is also supported by a lack of positive epidemiologic findings for evidence of liver carcinogenicity. Based on current understanding of the mode of action of dieldrin-induced liver tumors in mice, the appropriate conclusion is that dieldrin is a mouse specific liver carcinogen and it does not pose a cancer risk to humans.
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Affiliation(s)
- James E Klaunig
- Department of Environmental and Occupational Health, Indiana University School of Public Health, Bloomington, IN, USA
| | - Samuel M Cohen
- Department of Pathology, Microbiology, and Immunology and the Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA
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2
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Ishtiaq SM, Arshad MI, Khan JA. PPARγ signaling in hepatocarcinogenesis: Mechanistic insights for cellular reprogramming and therapeutic implications. Pharmacol Ther 2022; 240:108298. [PMID: 36243148 DOI: 10.1016/j.pharmthera.2022.108298] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/26/2022] [Accepted: 10/04/2022] [Indexed: 11/30/2022]
Abstract
Liver cancer or hepatocellular carcinoma (HCC) is leading cause of cancer-related mortalities globally. The therapeutic approaches for chronic liver diseases-associated liver cancers aimed at modulating immune check-points and peroxisome proliferator-activated receptor gamma (PPARγ) signaling pathway during multistep process of hepatocarcinogenesis that played a dispensable role in immunopathogenesis and outcomes of disease. Herein, the review highlights PPARγ-induced effects in balancing inflammatory (tumor necrosis factor alpha (TNF-α), interleukin (IL)-6, IL-1) and anti-inflammatory cytokines (IL-10, transforming growth factor beta (TGF-β), and interplay of PPARγ, hepatic stellate cells and fibrogenic niche in cell-intrinsic and -extrinsic crosstalk of hepatocarcinogenesis. PPARγ-mediated effects in pre-malignant microenvironment promote growth arrest, cell senescence and cell clearance in liver cancer pathophysiology. Furthermore, PPARγ-immune cell axis of liver microenvironment exhibits an immunomodulation strategy of resident immune cells of the liver (macrophages, natural killer cells, and dendritic cells) in concomitance with current clinical guidelines of the European Association for Study of Liver Diseases (EASL) for several liver diseases. Thus, mechanistic insights of PPARγ-associated high value targets and canonical signaling suggest PPARγ as a possible therapeutic target in reprogramming of hepatocarcinogenesis to decrease burden of liver cancers, worldwide.
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Affiliation(s)
- Syeda Momna Ishtiaq
- Institute of Physiology and Pharmacology, University of Agriculture, Faisalabad 38040, Pakistan
| | | | - Junaid Ali Khan
- Department of Pharmacology and Physiology, MNS University of Agriculture, Multan 60000, Pakistan.
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3
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Zhou J, Zhang X, Tang H, Yu J, Zu X, Xie Z, Yang X, Hu J, Tan F, Li Q, Lei X. Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) in autophagy-induced hepatocellular carcinoma. Clin Chim Acta 2020; 506:1-8. [PMID: 32109431 DOI: 10.1016/j.cca.2020.02.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/22/2020] [Accepted: 02/24/2020] [Indexed: 12/23/2022]
Abstract
Autophagy, an evolutionarily conserved catabolic process, is the most important pathogenic events in the development and progression of liver diseases. Deregulation of Nrf2 is proposed to play a key pathogenic role in hepatocellular carcinoma (HCC). Under certain pathophysiological conditions, such as oxidative stress, impaired autophagy is accompanied by the Nrf2 activation that leads to the detrimental effects favoring the proliferation and survival of HCC. Elucidating its role and potential mechanism is essential for understanding tumorigenesis and the development of effective clinical application. Nrf2 is participated in HCC proliferation, migration and invasion through autophagy pathways. These includes the negatively regulated-Nrf2 by Keap1 that participates in HCC tumorigenesis via regulating ROS production, in which autophagy may contribute to oxidant metabolic reprogramming of HCC cells. Post-transcriptional modifications, such as phosphorylation and ubiquitination of Nrf2, can be positively or negatively induced by multiple transcription factors. Nrf2 exhibits chemoresistance through its binding sites in the promoter region of the target genes. Nrf2 may be a valuable potential biomarker and therapeutic strategy for diagnostics, prognostics and treatment of HCC.
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Affiliation(s)
- Juan Zhou
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Key Laboratory of Tumor Microenvironment Response Drug Research, University of South China, Hengyang, Hunan 421001, PR China
| | - Xinxin Zhang
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Key Laboratory of Tumor Microenvironment Response Drug Research, University of South China, Hengyang, Hunan 421001, PR China
| | - Huifang Tang
- The First Affiliated Hospital of University of South China, Hengyang, Hunan 421001, PR China
| | - Jia Yu
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Key Laboratory of Tumor Microenvironment Response Drug Research, University of South China, Hengyang, Hunan 421001, PR China
| | - Xuyu Zu
- The First Affiliated Hospital of University of South China, Hengyang, Hunan 421001, PR China
| | - Zhizhong Xie
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Key Laboratory of Tumor Microenvironment Response Drug Research, University of South China, Hengyang, Hunan 421001, PR China
| | - Xiaoyan Yang
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Key Laboratory of Tumor Microenvironment Response Drug Research, University of South China, Hengyang, Hunan 421001, PR China
| | - Juan Hu
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Key Laboratory of Tumor Microenvironment Response Drug Research, University of South China, Hengyang, Hunan 421001, PR China
| | - Fang Tan
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Key Laboratory of Tumor Microenvironment Response Drug Research, University of South China, Hengyang, Hunan 421001, PR China
| | - Qing Li
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Key Laboratory of Tumor Microenvironment Response Drug Research, University of South China, Hengyang, Hunan 421001, PR China
| | - Xiaoyong Lei
- Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Institute of Pharmacy and Pharmacology, Key Laboratory of Tumor Microenvironment Response Drug Research, University of South China, Hengyang, Hunan 421001, PR China.
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4
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Xu D, Xu M, Jeong S, Qian Y, Wu H, Xia Q, Kong X. The Role of Nrf2 in Liver Disease: Novel Molecular Mechanisms and Therapeutic Approaches. Front Pharmacol 2019; 9:1428. [PMID: 30670963 PMCID: PMC6331455 DOI: 10.3389/fphar.2018.01428] [Citation(s) in RCA: 164] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 11/19/2018] [Indexed: 12/15/2022] Open
Abstract
Oxidative stress and inflammation are the most important pathogenic events in the development and progression of liver diseases. Nuclear erythroid 2-related factor 2 (Nrf2) is the master regulator of the cellular protection via induction of anti-inflammatory, antioxidant, and cyto-protective genes expression. Multiple studies have shown that activation or suppression of this transcriptional factor significantly affect progression of liver diseases. Comprehensive understanding the roles of Nrf2 activation/expression and the outcomes of its activators/inhibitors are indispensable for defining the mechanisms and therapeutic strategies against liver diseases. In this current review, we discussed recent advances in the function and principal mechanisms by regulating Nrf2 in liver diseases, including acute liver failure, hepatic ischemia-reperfusion injury (IRI), alcoholic liver disease (ALD), viral hepatitis, non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and hepatocellular carcinoma (HCC).
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Affiliation(s)
- Dongwei Xu
- Department of Liver Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Min Xu
- Department of Liver Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Seogsong Jeong
- Department of Liver Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yihan Qian
- School of Pharmacy, Fudan University, Shanghai, China
| | - Hailong Wu
- Shanghai Key Laboratory for Molecular Imaging, Collaborative Research Center, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Qiang Xia
- Department of Liver Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaoni Kong
- Department of Liver Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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Fathy AH, Bashandy MA, Bashandy SA, Mansour AM, Elsadek B. Sequential analysis and staging of a diethylnitrosamine-induced hepatocellular carcinoma in male Wistar albino rat model. Can J Physiol Pharmacol 2017; 95:1462-1472. [DOI: 10.1139/cjpp-2017-0413] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Hepatocellular carcinoma (HCC) is one of the most life-threatening cancers. The present study was designed to chronologically analyze the HCC chemically induced by diethylnitrosamine (DEN) in male Wistar rats during a 27-week period. DEN was given to rats in drinking water (100 mg/L) to induce HCC. In the present study, the DEN-administered groups recorded dramatic results in the tumor markers, oxidative stress, lipid profile, liver function, and hematological parameters at all intervals when compared with their corresponding values in the control groups. In addition, the morphometric analysis of livers of the DEN-administered groups (from 9 to 27 weeks) showed gradual enlargement and several grayish white nodules and foci on the peripheral surface of the liver as the features of HCC. In conclusion, the present sequential model chronologically analyzes all steps of hepatocarcinogenesis and presents a new staging system for classification of HCC that may be valuable for investigating the effects of anticarcinogenic compounds at varying stages of hepatocarcinogenesis in vivo.
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Affiliation(s)
- Abdallah H. Fathy
- Department of Zoology, Faculty of Science, Al-Azhar University, Cairo, Egypt
| | - Mohamed A. Bashandy
- Department of Zoology, Faculty of Science, Al-Azhar University, Cairo, Egypt
| | | | - Ahmed M. Mansour
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt
| | - Bakheet Elsadek
- Department of Biochemistry and Molecular Biology, Faculty of Pharmacy, Al-Azhar University, Assiut, Egypt
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Kaestner B, Spicher K, Jaehde U, Enzmann H. Effects of sorafenib and cisplatin on preneoplastic foci of altered hepatocytes in fetal turkey liver. Toxicol Res (Camb) 2017; 6:54-62. [PMID: 30090476 DOI: 10.1039/c6tx00342g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/28/2016] [Indexed: 12/20/2022] Open
Abstract
Foci of altered hepatocytes (FAH) were induced in fetal turkey liver (FTL) by diethyl nitrosamine. FAH in FTL were resistant to iron overload similar to FAH in humans and rodents. The mitotic index was significantly higher in FAH (6.2 mitosis in 1000 hepatocytes) than in extrafocal liver tissue (1.8 mitosis in 1000 hepatocytes). The calculation of the net growth rate based on both cell proliferation (mitosis) and cell death (TUNEL positive) revealed a threefold growth advantage of the FAH over the surrounding liver. Two well established anti-tumor substances from different chemical classes, different modes of action and with different clinical use in the treatment of hepatocellular carcinoma (HCC) were used to study their effect on FAH. Sorafenib is the only approved drug for systemic pharmacological treatment of HCC; cisplatin has been used for many years in hepatic arterial infusion. Cisplatin had no clear effect on number of size of FAH, cell proliferation (mitosis) or cell loss (TUNEL positive). Sorafenib enhanced the development of FAH. Morphometric quantification revealed a sorafenib-induced 2-3-fold increase in number (FAH per cm2 and FAH per cm3), size and volume fraction of FAH. This unexpected finding was confirmed in two experiments. The effect was driven by an increased cell proliferation in the FAH, resulting in an increased, 5.4-fold growth advantage of FAH versus the surrounding liver in sorafenib-treated FTL. In this model, sorafenib has a promoting effect on preneoplastic FAH. This might be of relevance for the treatment of patients with long term survival perspective, e.g. in an adjuvant setting.
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Affiliation(s)
- Bettina Kaestner
- Federal Institute for Drugs and Medical Devices , Bonn , Germany . ; ; Tel: +49 228 207 3315
| | - Karsten Spicher
- Federal Institute for Drugs and Medical Devices , Bonn , Germany . ; ; Tel: +49 228 207 3315
| | - Ulrich Jaehde
- Institute of Pharmacy , University of Bonn , Bonn , Germany
| | - Harald Enzmann
- Federal Institute for Drugs and Medical Devices , Bonn , Germany . ; ; Tel: +49 228 207 3315
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7
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Furtado KS, de Oliveira Andrade F, Campos A, Rosim MP, Vargas-Mendez E, Henriques A, De Conti A, Scolastici C, Barbisan LF, Carvalho RF, Moreno FS. β-ionone modulates the expression of miRNAs and genes involved in the metastatic phenotype of microdissected persistent preneoplastic lesions in rats submitted to hepatocarcinogenesis. Mol Carcinog 2016; 56:184-196. [PMID: 27061051 DOI: 10.1002/mc.22483] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 02/25/2016] [Accepted: 03/18/2016] [Indexed: 12/19/2022]
Abstract
MicroRNAs (miRNAs) are post-transcriptional gene expression regulators which expression is frequently altered in hepatocellular carcinoma (HCC). β-ionone (βI) is noted for its ability to inhibit persistent preneoplastic lesions (pPNLs) in liver rats. We evaluated the expression of miRNAs involved in carcinogenesis and possible targets modulated by βI, in pPNLs and surrounding of microdissected tissues. Rats subjected to resistant hepatocyte model were treated during promotion stage with βI (16 mg/100 g body weight) or corn oil (CO; 0.25 mL/100 g body weight; controls). Five animals receive no treatment (NT). In CO group, 38 and 29 miRNAs showed reduced expression relative to NT (P < 0.05) in pPNLs and surrounding, respectively. No miRNAs showed increased expression in surrounding of the CO compared to NT group; however, 30 miRNAs showed increased expression (P ≤ 0.05) in pPNLs of the CO group. There was no difference between βI and CO groups (P > 0.05) in the expression of miRNAs in surrounding. In pPNLs βI increased expression of miR-122 and miR-34a (P ≤ 0.05) and reduced of Igf2 (P ≤ 0.05), target of the latter, compared to CO. Additionally, βI decreased the expression of miR-181c and its target Gdf2 (P ≤ 0.05). βI reduced the expression of miR-181b and miR-708 (P ≤ 0.05) and increased the expression of their respective target mRNAs Timp3 and Mtss1 (P ≤ 0.05), relative to CO group. Modulation of miRNAs target genes by βI was confirmed in vitro. βI is a promising chemopreventive agent in the initial stages of hepatocarcinogenesis, as it modulates the expression of the miRNAs and target genes that can alter the metastatic phenotype of HCC. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Kelly Silva Furtado
- Laboratory of Diet, Nutrition, and Cancer, Faculty of Pharmaceutical Sciences, Department of Food and Experimental Nutrition, University of São Paulo, São Paulo, SP, Brazil
| | - Fábia de Oliveira Andrade
- Laboratory of Diet, Nutrition, and Cancer, Faculty of Pharmaceutical Sciences, Department of Food and Experimental Nutrition, University of São Paulo, São Paulo, SP, Brazil
| | - Adriana Campos
- Laboratory of Diet, Nutrition, and Cancer, Faculty of Pharmaceutical Sciences, Department of Food and Experimental Nutrition, University of São Paulo, São Paulo, SP, Brazil
| | - Mariana Papaléo Rosim
- Laboratory of Nutrigenomics and Programming, Faculty of Pharmaceutical Sciences, Department of Food and Experimental Nutrition, University of São Paulo, São Paulo, SP, Brazil
| | - Ernesto Vargas-Mendez
- Laboratory of Diet, Nutrition, and Cancer, Faculty of Pharmaceutical Sciences, Department of Food and Experimental Nutrition, University of São Paulo, São Paulo, SP, Brazil
| | - Aline Henriques
- Laboratory of Diet, Nutrition, and Cancer, Faculty of Pharmaceutical Sciences, Department of Food and Experimental Nutrition, University of São Paulo, São Paulo, SP, Brazil
| | - Aline De Conti
- Laboratory of Diet, Nutrition, and Cancer, Faculty of Pharmaceutical Sciences, Department of Food and Experimental Nutrition, University of São Paulo, São Paulo, SP, Brazil
| | - Clarissa Scolastici
- Laboratory of Diet, Nutrition, and Cancer, Faculty of Pharmaceutical Sciences, Department of Food and Experimental Nutrition, University of São Paulo, São Paulo, SP, Brazil
| | - Luis Fernando Barbisan
- Laboratory of Experimental Chemical Carcinogenesis, Department of Morphology, Botucatu, Institute of Biosciences, São Paulo State University, São Paulo, Brazil
| | - Robson Francisco Carvalho
- Laboratory of Striated Muscle Biology, Department of Morphology, Botucatu, Institute of Biosciences, São Paulo State University, São Paulo, Brazil
| | - Fernando Salvador Moreno
- Laboratory of Diet, Nutrition, and Cancer, Faculty of Pharmaceutical Sciences, Department of Food and Experimental Nutrition, University of São Paulo, São Paulo, SP, Brazil
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Trosko JE. Human adult stem cells as the target cells for the initiation of carcinogenesis and for the generation of "cancer stem cells". Int J Stem Cells 2014; 1:8-26. [PMID: 24855504 DOI: 10.15283/ijsc.2008.1.1.8] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2008] [Indexed: 01/12/2023] Open
Abstract
The inference to stem cells has been found in ancient myths and the concept of stem cells has existed in the fields of plant biology, developmental biology and embryology for decades. In the field of cancer research, the stem cell theory was one of the earliest hypotheses on the origin of a cancer from a single cell. However, an opposing hypothesis had it that an adult differentiated somatic cell could "de-differentiate" to become a cancer cell. Only within the last decade, via the "cloning" of Dolly, the sheep, did the field of stem cell biology really trigger an exciting revolution in biological research. The isolation of human embryonic stem cells has created a true revolution in the life sciences that has led to the hope that these human stem cells could lead to (a) basic science understanding of gene regulation during differentiation and development; (b) stem cell therapy; (c) gene therapy via stem cells; (d) the use of stem cells for drug discovery; (e) screening for toxic effects of chemicals; and (f) understand the aging and diseases of aging processes.
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Affiliation(s)
- James E Trosko
- Department of Pediatrics/Human Development, College of Human Medicine, Michigan State University, East Lansing, Michigan 48824, USA
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Guariento AH, Furtado KS, de Conti A, Campos A, Purgatto E, Carrilho J, Shinohara EMG, Tryndyak V, Han T, Fuscoe JC, Ross SA, Beland FA, Pogribny IP, Moreno FS. Transcriptomic responses provide a new mechanistic basis for the chemopreventive effects of folic acid and tributyrin in rat liver carcinogenesis. Int J Cancer 2014; 135:7-18. [PMID: 24302446 DOI: 10.1002/ijc.28642] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 11/12/2013] [Accepted: 11/20/2013] [Indexed: 12/17/2022]
Abstract
The steady increase in the incidence and mortality of hepatocellular carcinoma (HCC) signifies a crucial need to understand better its pathogenesis to improve clinical management and prevention of the disease. The aim of this study was to investigate molecular mechanisms for the chemopreventive effects of folic acid and tributyrin alone or in combination on rat hepatocarcinogenesis. Male Wistar rats were subjected to a classic "resistant hepatocyte" model of liver carcinogenesis and treated with folic acid and tributyrin alone or in combination for 5 weeks during promotion stage. Treatment with folic acid and tributyrin alone or in combination strongly inhibited the development of glutathione-S-transferase placental form (GSTP)-positive foci. Microarray analysis showed significant changes in gene expression. A total of 498, 655 and 940 of differentially expressed genes, involved in cell cycle, p53-signaling, angiogenesis and Wnt pathways, was identified in the livers of rats treated with folic acid, tributyrin or folic acid and tributyrin. A detailed analysis of these differentially expressed genes revealed that treatments inhibited angiogenesis in the preneoplastic livers. This was evidenced by the fact that 30 out of 77 differentially expressed genes common to all three treatments are involved in the regulation of the angiogenesis pathway. The inhibition of angiogenesis was confirmed by reduced levels of CD34 protein. In conclusion, the tumor-suppressing activity of folic acid and tributyrin is associated with inhibition of angiogenesis at early stages of rat liver carcinogenesis. Importantly, the combination of folic acid and tributyrin has stronger chemopreventive effect than each of the compounds alone.
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Affiliation(s)
- Aline H Guariento
- Laboratory of Diet, Nutrition, and Cancer, Department of Food and Experimental Nutrition, University of São Paulo, São Paulo, Brazil
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Liu J, Li G, Liu D, Liu J. FH535 inhibits the proliferation of HepG2 cells via downregulation of the Wnt/β-catenin signaling pathway. Mol Med Rep 2014; 9:1289-92. [PMID: 24482011 DOI: 10.3892/mmr.2014.1928] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 01/23/2014] [Indexed: 12/16/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is a primary cancer of the liver. Target therapy may improve prognosis of HCC. In the present study, we evaluated the inhibition of the Wnt/β-catenin pathway as a potential therapeutic approach. HepG2 cells were treated with the β-catenin inhibitor FH535. β-catenin protein expression was semi-quantitatively assessed using western blot analysis. Cell proliferation was examined with a 3‑(4,5-dimethyl-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt (MTS) assay. The mRNA expression of nitric oxide synthase (iNOS) was detected by reverse transcription polymerase chain reaction. The Griess assay was used to determine nitric oxide (NO) concentration. FH535 inhibited the proliferation of HepG2 cells and decreased β-catenin protein expression. mRNA expression of iNOS, a target gene of the Wnt/β-catenin pathway, was decreased in FH535‑treated HepG2 cells compared to the control group. NO production was also reduced by FH535. In conclusion, the β-catenin inhibitor FH535 may inhibit HCC cell proliferation via downregulation of the Wnt/β-catenin pathway. Thus, targeting this pathway may be useful in HCC therapy.
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Affiliation(s)
- Jing Liu
- Department of Ophthalmology, The Second Hospital of Shandong University, Jinan, Shandong 250033, P.R. China
| | - Guangbing Li
- Department of Liver Transplantation and Hepatobiliary Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Dejie Liu
- Department of Anesthesiology, Qilu Hospital Affiliated to Shandong University, Jinan, Shandong 250012, P.R. China
| | - Jun Liu
- Department of Liver Transplantation and Hepatobiliary Surgery, Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
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Enzmann HG, Brunnemann KD, Kaestner B, Iatropoulos MJ, Williams GM. Dose-dependent induction of preneoplastic lesions by the tobacco-specific nitrosamine carcinogen NNK in the in ovo carcinogenicity assessment (IOCA) assay. EXPERIMENTAL AND TOXICOLOGIC PATHOLOGY : OFFICIAL JOURNAL OF THE GESELLSCHAFT FUR TOXIKOLOGISCHE PATHOLOGIE 2014; 66:35-40. [PMID: 24054761 DOI: 10.1016/j.etp.2013.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 06/23/2013] [Accepted: 08/19/2013] [Indexed: 11/17/2022]
Abstract
The potential of the carcinogenic tobacco specific nitrosamine 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-1-butanone (NNK) to induce preneoplastic hepatocellular altered foci (HAF) was tested in the in ovo carcinogenicity assessment (IOCA) assay. Single doses of NNK over a dose range from 0.1 mg to 6 mg were injected into fertilized turkey eggs prior to incubation for 24 days. The livers were investigated by histological, histochemical and morphometric methods. Mortality was increased for eggs exposed to 6 mg. In this group, the whole livers were severely altered, showing pronounced changes of nucleus size and signs of cell death. At the dose of 2 mg various types of foci of altered hepatocytes (HAF) were observed. Basophilic cell foci of the solid or tubular type were most frequent. The NNK-induced HAF were very similar to the preneoplastic lesions that occur in the livers of mammals during hepatocarcinogenesis which are regarded as early indicators of carcinogenesis. The similarity to the HAF in rodents included histochemically detectable alterations like decreased activities of glucose-6-phosphatase, adenosine triphosphatase and glycogen phosphorylase. At doses of 1 mg or below, no HAF were detected. At all dose levels an increased occurrence of enlarged hepatocytes with enlarged nuclei and prominent nucleoli (karyomegalic hepatocytes) were observed. The increase in karyomegalic hepatocytes was also statistically significant at the low dose of 0.1 mg/kg NNK but the dose-effect curve for their induction was clearly non-linear. Induction of HAF and karyomegalic hepatocytes in ovo is a simple (one dose), rapid (24 days) and inexpensive (no animal purchase or housing) experimental approach for studies on chemically induced hepatocarcinogenesis.
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Affiliation(s)
- Harald G Enzmann
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn Germany.
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Enzmann H, Brunnemann K, Iatropoulos M, Shpyleva S, Lukyanova N, Todor I, Moore M, Spicher K, Chekhun V, Tsuda H, Williams G. Inter-laboratory comparison of turkey in ovo carcinogenicity assessment (IOCA) of hepatocarcinogens. ACTA ACUST UNITED AC 2013; 65:729-35. [DOI: 10.1016/j.etp.2012.09.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Revised: 08/03/2012] [Accepted: 09/24/2012] [Indexed: 10/27/2022]
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13
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de Conti A, Tryndyak V, Koturbash I, Heidor R, Kuroiwa-Trzmielina J, Ong TP, Beland FA, Moreno FS, Pogribny IP. The chemopreventive activity of the butyric acid prodrug tributyrin in experimental rat hepatocarcinogenesis is associated with p53 acetylation and activation of the p53 apoptotic signaling pathway. Carcinogenesis 2013; 34:1900-6. [PMID: 23568954 DOI: 10.1093/carcin/bgt124] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The reversibility of non-genotoxic phenotypic alterations has been explored in order to develop novel preventive and therapeutic approaches for cancer control. Previously, it has been demonstrated that histone deacetylase (HDAC) inhibitor tributyrin, a butyric acid prodrug, to have chemopreventive effects on rat hepatocarcinogenesis. The goal of this study was to determine molecular mechanisms associated with the chemopreventive activity of tributyrin. Male Wistar rats were allocated randomly to untreated control group and two experimental groups. Rats in the experimental group 1 were treated with maltodextrin (3g/kg body wt), and rats in experimental group 2 were treated with tributyrin (2g/kg body wt) daily for 8 weeks. Two weeks after treatment initiation, rats from experimental groups were subjected to a 'resistant hepatocyte' model of hepatocarcinogenesis. Treatment with tributyrin resulted in lower HDAC activity and Hdac3 and Hdac4 gene expression, and an increase of histone H3 lysine 9 and 18 and histone H4 lysine 16 acetylation as compared with the experimental group 1. In addition to the increase in histone acetylation, tributyrin caused an increase in the acetylation of the nuclear p53 protein. These changes were accompanied by a normalization of the p53-signaling network, particularly by the upregulation of pro-apoptotic genes, and a consequent increase of apoptosis and autophagy in the livers of tributyrin-treated rats. These results indicate that the chemopreventive activity of tributyrin may be related to an increase of histone and p53 acetylation, which could lead to the induction of the p53 apoptotic pathway.
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Affiliation(s)
- Aline de Conti
- Department of Food and Experimental Nutrition, Laboratory of Diet, Nutrition and Cancer, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
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14
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Aguiar e Silva MA, Vechetti-Junior IJ, Nascimento AFD, Furtado KS, Azevedo L, Ribeiro DA, Barbisan LF. Effects of swim training on liver carcinogenesis in male Wistar rats fed a low-fat or high-fat diet. Appl Physiol Nutr Metab 2012; 37:1101-9. [DOI: 10.1139/h2012-129] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The present study aimed to investigate the beneficial effects of swim training on the promotion–progression stages of rat liver carcinogenesis. Male Wistar rats were submitted to chemically induced liver carcinogenesis and allocated into 4 major groups, according their dietary regimen (16 weeks) and swim training of 5 days per week (8 weeks): 2 groups were fed low-fat diet (LFD, 6% fat) and trained or not trained and 2 groups were fed high-fat diet (HFD, 21% fat) and trained or not trained. At week 20, the animals were killed and liver samples were processed for histological analyses; immunohistochemical detection of persistent or remodeling preneoplastic lesions (pPNL and rPNL) expressing placental glutathione S-transferase (GST-P) enzyme; or proliferating cell nuclear antigen (PCNA), cleaved caspase-3, and bcl-2 protein levels by Western blotting or malonaldehyde (MDA) and total glutathione detection by HPLC. Overall analysis indicated that swim training reduced the body weight and body fat in both LFD and HFD groups, normalized total cholesterol levels in the HFD group while decreased the MDA levels, increased glutathione levels and both number of GST-P-positive pPNL and hepatocellular adenomas in LFD group. Also, a favorable balance in PCNA, cleaved caspase-3, and bcl-2 levels was detected in the liver from the LFD-trained group in relation to LFD-untrained group. The findings of this study indicate that the swim training protocol as a result of exercise postconditioning may attenuate liver carcinogenesis under an adequate dietary regimen with lowered fat intake.
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Affiliation(s)
- Marco Aurélio Aguiar e Silva
- Post-Graduation Program in General and Applied Biology, Institute of Biosciences, UNESP, Sao Paulo State University, Botucatu 18618-970, SP, Brazil
| | - Ivan José Vechetti-Junior
- Post-Graduation Program in General and Applied Biology, Institute of Biosciences, UNESP, Sao Paulo State University, Botucatu 18618-970, SP, Brazil
| | - André Ferreira do Nascimento
- Department of Clinical Medicine, School of Medicine, UNESP, Sao Paulo State University, 18618-970 Botucatu, SP, Brazil
| | - Kelly Silva Furtado
- School of Medicine, Department of Pathology, UNESP, Sao Paulo State University, 18618-970 Botucatu, SP, Brazil
| | - Luciana Azevedo
- Faculty of Nutrition, UNIFAL, Federal University of Alfenas, 37130-000, Alfenas, MG, Brazil
| | - Daniel Araki Ribeiro
- Department of Biosciences, UNIFESP, Federal University of Sao Paulo, 11060-001, Santos, SP, Brazil
| | - Luis Fernando Barbisan
- Department of Morphology, Institute of Biosciences, UNESP, Sao Paulo State University, 18618-970 Botucatu, SP, Brazil
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15
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Sargent LM, Hubbs AF, Young SH, Kashon ML, Dinu CZ, Salisbury JL, Benkovic SA, Lowry DT, Murray AR, Kisin ER, Siegrist KJ, Battelli L, Mastovich J, Sturgeon JL, Bunker KL, Shvedova AA, Reynolds SH. Single-walled carbon nanotube-induced mitotic disruption. Mutat Res 2012; 745:28-37. [PMID: 22178868 PMCID: PMC4696046 DOI: 10.1016/j.mrgentox.2011.11.017] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 11/29/2011] [Indexed: 04/08/2023]
Abstract
Carbon nanotubes were among the earliest products of nanotechnology and have many potential applications in medicine, electronics, and manufacturing. The low density, small size, and biological persistence of carbon nanotubes create challenges for exposure control and monitoring and make respiratory exposures to workers likely. We have previously shown mitotic spindle aberrations in cultured primary and immortalized human airway epithelial cells exposed to 24, 48 and 96 μg/cm(2) single-walled carbon nanotubes (SWCNT). To investigate mitotic spindle aberrations at concentrations anticipated in exposed workers, primary and immortalized human airway epithelial cells were exposed to SWCNT for 24-72 h at doses equivalent to 20 weeks of exposure at the Permissible Exposure Limit for particulates not otherwise regulated. We have now demonstrated fragmented centrosomes, disrupted mitotic spindles and aneuploid chromosome number at those doses. The data further demonstrated multipolar mitotic spindles comprised 95% of the disrupted mitoses. The increased multipolar mitotic spindles were associated with an increased number of cells in the G2 phase of mitosis, indicating a mitotic checkpoint response. Nanotubes were observed in association with mitotic spindle microtubules, the centrosomes and condensed chromatin in cells exposed to 0.024, 0.24, 2.4 and 24 μg/cm(2) SWCNT. Three-dimensional reconstructions showed carbon nanotubes within the centrosome structure. The lower doses did not cause cytotoxicity or reduction in colony formation after 24h; however, after three days, significant cytotoxicity was observed in the SWCNT-exposed cells. Colony formation assays showed an increased proliferation seven days after exposure. Our results show significant disruption of the mitotic spindle by SWCNT at occupationally relevant doses. The increased proliferation that was observed in carbon nanotube-exposed cells indicates a greater potential to pass the genetic damage to daughter cells. Disruption of the centrosome is common in many solid tumors including lung cancer. The resulting aneuploidy is an early event in the progression of many cancers, suggesting that it may play a role in both tumorigenesis and tumor progression. These results suggest caution should be used in the handling and processing of carbon nanotubes.
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Affiliation(s)
- L M Sargent
- National Institute for Occupational Safety and Health, Morgantown, WV 26505, United States.
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16
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Abstract
MicroRNAs, potent negative modulators of gene expression, are involved in the regulation of fundamental cellular processes, including cell differentiation, metabolic regulation, signal transduction, cell proliferation and apoptosis. Aberrant levels of miRNAs have been documented in all major human cancers, leading to the suggestion that deregulation of miRNA expression might be significant in tumorigenesis. This review presents the current evidence that demonstrates the involvement of miRNA deregulation in the early stages of lung, liver and breast carcinogenesis induced by chemical carcinogens, suggesting their major role as contributors to the pathogenesis of cancer.
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Affiliation(s)
- Igor P Pogribny
- Division of Biochemical Toxicology, National Center for Toxicological Research, 3900 NCTR Road, Jefferson, AR 72079, USA.
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17
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Tabish AM, Poels K, Hoet P, Godderis L. Epigenetic factors in cancer risk: effect of chemical carcinogens on global DNA methylation pattern in human TK6 cells. PLoS One 2012; 7:e34674. [PMID: 22509344 PMCID: PMC3324488 DOI: 10.1371/journal.pone.0034674] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 03/06/2012] [Indexed: 12/19/2022] Open
Abstract
In the current study, we assessed the global DNA methylation changes in human lymphoblastoid (TK6) cells in vitro in response to 5 direct and 10 indirect-acting genotoxic agents. TK6 cells were exposed to the selected agents for 24 h in the presence and/or absence of S9 metabolic mix. Liquid chromatography-mass spectrometry was used for quantitative profiling of 5-methyl-2'-deoxycytidine. The effect of exposure on 5-methyl-2'-deoxycytidine between control and exposed cultures was assessed by applying the marginal model with correlated residuals on % global DNA methylation data. We reported the induction of global DNA hypomethylation in TK6 cells in response to S9 metabolic mix, under the current experimental settings. Benzene, hydroquinone, styrene, carbon tetrachloride and trichloroethylene induced global DNA hypomethylation in TK6 cells. Furthermore, we showed that dose did not have an effect on global DNA methylation in TK6 cells. In conclusion we report changes in global DNA methylation as an early event in response to agents traditionally considered as genotoxic.
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Affiliation(s)
- Ali M Tabish
- Department of Occupational, Environmental and Insurance Medicine, Katholieke Universiteit Leuven, Leuven, Belgium.
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18
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Nalesnik MA, Tseng G, Ding Y, Xiang GS, Zheng ZL, Yu Y, Marsh JW, Michalopoulos GK, Luo JH. Gene deletions and amplifications in human hepatocellular carcinomas: correlation with hepatocyte growth regulation. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:1495-508. [PMID: 22326833 DOI: 10.1016/j.ajpath.2011.12.021] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 12/09/2011] [Accepted: 12/22/2011] [Indexed: 12/29/2022]
Abstract
Tissues from 98 human hepatocellular carcinomas (HCCs) obtained from hepatic resections were subjected to somatic copy number variation (CNV) analysis. Most of these HCCs were discovered in livers resected for orthotopic transplantation, although in a few cases, the tumors themselves were the reason for the hepatectomies. Genomic analysis revealed deletions and amplifications in several genes, and clustering analysis based on CNV revealed five clusters. The LSP1 gene had the most cases with CNV (46 deletions and 5 amplifications). High frequencies of CNV were also seen in PTPRD (21/98), GNB1L (18/98), KIAA1217 (18/98), RP1-1777G6.2 (17/98), ETS1 (11/98), RSU1 (10/98), TBC1D22A (10/98), BAHCC1 (9/98), MAML2 (9/98), RAB1B (9/98), and YIF1A (9/98). The existing literature regarding hepatocytes or other cell types has connected many of these genes to regulation of cytoskeletal architecture, signaling cascades related to growth regulation, and transcription factors directly interacting with nuclear signaling complexes. Correlations with existing literature indicate that genomic lesions associated with HCC at the level of resolution of CNV occur on many genes associated directly or indirectly with signaling pathways operating in liver regeneration and hepatocyte growth regulation.
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Affiliation(s)
- Michael A Nalesnik
- Department of Pathology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15241, USA
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19
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Su LJ, Mahabir S, Ellison GL, McGuinn LA, Reid BC. Epigenetic Contributions to the Relationship between Cancer and Dietary Intake of Nutrients, Bioactive Food Components, and Environmental Toxicants. Front Genet 2012; 2:91. [PMID: 22303385 PMCID: PMC3266615 DOI: 10.3389/fgene.2011.00091] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 12/06/2011] [Indexed: 12/21/2022] Open
Abstract
Epigenetics is the study of heritable changes in gene expression that occur without a change in DNA sequence. Cancer is a multistep process derived from combinational crosstalk between genetic alterations and epigenetic influences through various environmental factors. The observation that epigenetic changes are reversible makes them an attractive target for cancer prevention. Until recently, there have been difficulties studying epigenetic mechanisms in interactions between dietary factors and environmental toxicants. The development of the field of cancer epigenetics during the past decade has been advanced rapidly by genome-wide technologies - which initially employed microarrays but increasingly are using high-throughput sequencing - which helped to improve the quality of the analysis, increase the capacity of sample throughput, and reduce the cost of assays. It is particularly true for applications of cancer epigenetics in epidemiologic studies that examine the relationship among diet, epigenetics, and cancer because of the issues of tissue heterogeneity, the often limiting amount of DNA samples, and the significant cost of the analyses. This review offers an overview of the state of the science in nutrition, environmental toxicants, epigenetics, and cancer to stimulate further exploration of this important and developing area of science. Additional epidemiologic research is needed to clarify the relationship between these complex epigenetic mechanisms and cancer.
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Affiliation(s)
- L. Joseph Su
- Modifiable Risk Factors Branch, Division of Cancer Control and Population Sciences, National Cancer InstituteBethesda, MD, USA
| | - Somdat Mahabir
- Modifiable Risk Factors Branch, Division of Cancer Control and Population Sciences, National Cancer InstituteBethesda, MD, USA
| | - Gary L. Ellison
- Modifiable Risk Factors Branch, Division of Cancer Control and Population Sciences, National Cancer InstituteBethesda, MD, USA
| | - Laura A. McGuinn
- Modifiable Risk Factors Branch, Division of Cancer Control and Population Sciences, National Cancer InstituteBethesda, MD, USA
| | - Britt C. Reid
- Modifiable Risk Factors Branch, Division of Cancer Control and Population Sciences, National Cancer InstituteBethesda, MD, USA
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20
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Abstract
Cancer encompasses a highly heterogeneous group of diseases. It has been thought that transition from promotion to progression in carcinogenesis may be driven primarily by epigenetic abnormalities. Diet is known to play crucial roles in cancer etiology and has an important role in epigenetics. Current knowledge in the interrelationship among cancer, nutrition and epigenetics is reviewed.
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Affiliation(s)
- L Joseph Su
- Division of Cancer Controls and Population Sciences, National Cancer Institute, Rockville, MD, USA.
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21
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Shpyleva SI, Muskhelishvili L, Tryndyak VP, Koturbash I, Tokar EJ, Waalkes MP, Beland FA, Pogribny IP. Chronic administration of 2-acetylaminofluorene alters the cellular iron metabolism in rat liver. Toxicol Sci 2011; 123:433-40. [PMID: 21785164 DOI: 10.1093/toxsci/kfr193] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Dysregulated intracellular iron homeostasis has been found not only in rodent and human hepatocellular carcinomas but also in several preneoplastic pathological states associated with hepatocarcinogenesis; however, the precise underlying mechanisms of metabolic iron disturbances in preneoplastic liver and the role of these disturbances remain unexplored. In the present study, using an in vivo model of rat hepatocarcinogenesis induced by 2-acetylaminofluorene, we found extensive alterations in cellular iron metabolism at preneoplastic stages of liver carcinogenesis. These were characterized by a substantial decrease in the levels of cytoplasmic non-heme iron in foci of initiated hepatocytes and altered expression of the major genes responsible for the proper maintenance of intracellular iron homeostasis. Gene expression analysis revealed that the decreased intracellular levels of iron in preneoplastic foci might be attributed to increased iron export from the cells, driven by upregulation of ferroportin (Fpn1), the only known non-heme iron exporter. Likewise, increased Fpn1 gene expression was found in vitro in TRL1215 rat liver cells with an acquired malignant phenotype, suggesting that upregulation of Fpn1 might be a specific feature of neoplastically transformed cells. Other changes observed in vivo included the downregulation of hepcidin (Hamp) gene, a key regulator of Fpn1, and this was accompanied by decreased levels of CCAAT/enhancer binding proteins alpha and beta, especially at the Hamp promoter. In conclusion, our results demonstrate the significance of altered intracellular iron metabolism in the progression of liver carcinogenesis and suggest that correction of these alterations could possibly affect liver cancer development.
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Affiliation(s)
- Svitlana I Shpyleva
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079, USA
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22
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Pogribny IP, Muskhelishvili L, Tryndyak VP, Beland FA. The role of epigenetic events in genotoxic hepatocarcinogenesis induced by 2-acetylaminofluorene. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2011; 722:106-13. [DOI: 10.1016/j.mrgentox.2010.02.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 02/20/2010] [Indexed: 12/15/2022]
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23
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Nesnow S, Padgett WT, Moore T. Propiconazole induces alterations in the hepatic metabolome of mice: relevance to propiconazole-induced hepatocarcinogenesis. Toxicol Sci 2011; 120:297-309. [PMID: 21278054 DOI: 10.1093/toxsci/kfr012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Propiconazole is a mouse hepatotumorigenic fungicide and has been the subject of recent investigations into its carcinogenic mechanism of action. The goals of this study were (1) to identify metabolomic changes induced in the liver by increasing doses of propiconazole in mice, (2) to interpret these results with key previously reported biochemical, transcriptomic, and proteomic findings obtained from mouse liver under the same treatment conditions, and (3) to relate these alterations to those associated with the carcinogenesis process. Propiconazole was administered to male CD-1 mice in the feed for 4 days with six mice per feed level (500, 1250, and 2500 ppm). The 2500 ppm dose level had previously been shown to induce both adenocarcinomas and adenomas in mouse liver after a 2-year continuous feed regimen. Endogenous biochemicals were profiled using liquid chromatography/mass spectrometry and gas chromatography/mass spectrometry methods and 261 were detected. The most populous biochemical class detected was lipids, followed by amino acids and then carbohydrates. Nucleotides, cofactors and vitamins, energy, peptides, and xenobiotics were also represented. Of the biochemicals detected, 159 were significantly altered by at least one dose of propiconazole and many showed strong dose responses. Many alterations in the levels of biochemicals were found in the glycogen metabolism, glycolysis, lipolysis, carnitine, and the tricarboxylic acid cycle pathways Several groups of metabolomic responses were ascribed to the metabolism and clearance of propiconazole: glucuronate, glutathione, and cysteine pathways. Groups of metabolic responses supported previous hypotheses on key events that can lead to propiconazole-induced tumorigenesis: oxidative stress and increases in the cholesterol biosynthesis pathway. Groups of metabolomic responses identified biomarkers associated with neoplasia: increases in glycolysis and increases in the levels of spermidine, sarcosine, and pseudouridine. These results extended the companion transcriptomic and proteomic studies and provided a more complete understanding of propiconazole's effects in mouse liver.
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Affiliation(s)
- Stephen Nesnow
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
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24
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Bidinotto LT, Costa CARA, Salvadori DMF, Costa M, Rodrigues MAM, Barbisan LF. Protective effects of lemongrass (Cymbopogon citratus STAPF) essential oil on DNA damage and carcinogenesis in female Balb/C mice. J Appl Toxicol 2010; 31:536-44. [DOI: 10.1002/jat.1593] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 07/09/2010] [Accepted: 08/06/2010] [Indexed: 11/11/2022]
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25
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Sargent LM, Reynolds SH, Castranova V. Potential pulmonary effects of engineered carbon nanotubes:in vitrogenotoxic effects. Nanotoxicology 2010; 4:396-408. [DOI: 10.3109/17435390.2010.500444] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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26
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Sargent LM, Shvedova AA, Hubbs AF, Salisbury JL, Benkovic SA, Kashon ML, Lowry DT, Murray AR, Kisin ER, Friend S, McKinstry KT, Battelli L, Reynolds SH. Induction of aneuploidy by single-walled carbon nanotubes. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2009; 50:708-17. [PMID: 19774611 DOI: 10.1002/em.20529] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Engineered carbon nanotubes are newly emerging manufactured particles with potential applications in electronics, computers, aerospace, and medicine. The low density and small size of these biologically persistent particles makes respiratory exposures to workers likely during the production or use of commercial products. The narrow diameter and great length of single-walled carbon nanotubes (SWCNT) suggest the potential to interact with critical biological structures. To examine the potential of nanotubes to induce genetic damage in normal lung cells, cultured primary and immortalized human airway epithelial cells were exposed to SWCNT or a positive control, vanadium pentoxide. After 24 hr of exposure to either SWCNT or vanadium pentoxide, fragmented centrosomes, multiple mitotic spindle poles, anaphase bridges, and aneuploid chromosome number were observed. Confocal microscopy demonstrated nanotubes within the nucleus that were in association with cellular and mitotic tubulin as well as the chromatin. Our results are the first to report disruption of the mitotic spindle by SWCNT. The nanotube bundles are similar to the size of microtubules that form the mitotic spindle and may be incorporated into the mitotic spindle apparatus.
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Affiliation(s)
- L M Sargent
- Toxicology and Molecular Biology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Morgantown, WV 26505, USA.
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27
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Said RA, Grassi TF, Scolastici C, Alves de Lima RO, Darros BR, Barbisan LF, de Camargo JLV. Absence of chemopreventive influence of propolis on the rat liver altered foci development. ACTA ACUST UNITED AC 2009; 62:405-12. [PMID: 19628380 DOI: 10.1016/j.etp.2009.05.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 05/20/2009] [Accepted: 05/28/2009] [Indexed: 01/10/2023]
Abstract
Propolis (bee glue) is a complex mixture of natural substances that exhibits a broad spectrum of biological activities. As the possibility exists that it may exert a chemopreventive role against cancer development, the present study aimed to evaluate the chemopreventive influence of a Brazilian aqueous propolis extract (APE) in a rat two-stage (initiation-promotion) medium-term bioassay for chemical liver carcinogenesis. Male Wistar rats were sequentially initiated with diethylnitrosamine (DEN, 200mg/kgb.w.) and, 2 weeks later, exposed to a diet containing hexachlorobenzene (HCB, 100ppm) and to APE 0.1% through drinking water for 6 weeks. Appropriate control groups were also established. The animals were sacrificed at the weeks 8th and 30th when liver samples were processed to evaluate the development of altered hepatocyte foci (AHF) identified under hematoxylin and eosin (H&E) staining and by the immunohistochemical expression of the enzyme glutathione S-transferase placental form (GST-P). The results indicate that APE 0.1% did not protect against the development of any of the differentially identified putative preneoplastic foci in DEN-initiated animals, exposed or not to the promoting agent HCB. Also, APE 0.1% by itself did not significantly induce any AHF, what is in line with its already known absence of genotoxic potential. Our results indicate that an aqueous extract of Brazilian propolis did not exert chemoprevention on the hepatocarcinogenesis process chemically induced in the rat.
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Affiliation(s)
- Roueda Abou Said
- Department of Environmental and Agrarian Sciences, Santa Cruz State University, Ilhéus, Bahia, Brazil
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28
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Tryndyak VP, Ross SA, Beland FA, Pogribny IP. Down-regulation of the microRNAs miR-34a, miR-127, and miR-200b in rat liver during hepatocarcinogenesis induced by a methyl-deficient diet. Mol Carcinog 2009; 48:479-87. [PMID: 18942116 DOI: 10.1002/mc.20484] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Altered expression of microRNAs (miRNAs) has been reported in diverse human cancers; however, the down-regulation or up-regulation of any particular miRNAs in cancer is not sufficient to address the role of these changes in carcinogenesis. In this study, using the rat model of liver carcinogenesis induced by a methyl-deficient diet, which is relevant to the hepatocarcinogenesis in humans associated with viral hepatitis C and B infections, alcohol exposure and metabolic liver diseases, we showed that the development of hepatocellular carcinoma (HCC) is characterized by prominent early changes in expression of miRNA genes, specifically by inhibition of expression of microRNAs miR-34a, miR-127, miR-200b, and miR-16a involved in the regulation of apoptosis, cell proliferation, cell-to-cell connection, and epithelial-mesenchymal transition. The mechanistic link between these alterations in miRNAs expression and the development of HCC was confirmed by the corresponding changes in the levels of E2F3, NOTCH1, BCL6, ZFHX1B, and BCL2 proteins targeted by these miRNAs. The significance of miRNAs expression dysregulation in respect to hepatocarcinogenesis was confirmed by the persistence of these miRNAs alterations in the livers of methyl-deficient rats re-fed a methyl-adequate diet. Altogether, the early occurrence of alterations in miRNAs expression and their persistence during the entire process of hepatocarcinogenesis indicate that the dysregulation of microRNAs expression may be an important contributing factor in the development of HCC.
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Affiliation(s)
- Volodymyr P Tryndyak
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079, USA
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29
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Pogribny IP, Shpyleva SI, Muskhelishvili L, Bagnyukova TV, James SJ, Beland FA. Role of DNA damage and alterations in cytosine DNA methylation in rat liver carcinogenesis induced by a methyl-deficient diet. Mutat Res 2009; 669:56-62. [PMID: 19442675 DOI: 10.1016/j.mrfmmm.2009.05.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 04/27/2009] [Accepted: 05/04/2009] [Indexed: 12/16/2022]
Abstract
Currently, cancer is recognized as a disease provoked by both genetic and epigenetic events. However, the significance of early genetic and epigenetic alterations with respect to carcinogenic process in general and to liver carcinogenesis in particular remains unexplored. A lack of knowledge regarding how specific alterations during early preneoplasia may be mechanistically related to tumor formation creates a major gap in understanding the role of these genetic and epigenetic abnormalities in carcinogenesis. In the present study we investigated the contribution of DNA damage and epigenetic alterations to liver carcinogenesis induced by a methyl-deficient diet. Feeding Fisher 344 rats a methyl-deficient diet for 9 weeks resulted in DNA damage and aberrant DNA methylation. This was evidenced by an early up-regulation of the base excision DNA repair genes, accumulation of 8-oxodeoxyguanosine and 3'OH-end strand breaks in DNA, pronounced global loss of DNA methylation, and hypermethylation of CpG islands in the livers of methyl-deficient rats. These abnormalities were completely restored in the livers of rats exposed to methyl-deficiency for 9 weeks after removal of the methyl-deficient diet and re-feeding a methyl-sufficient diet. However, when rats were fed a methyl-deficient diet for 18 week and then given a methyl-sufficient diet, only DNA lesions were repaired. The methyl-sufficient diet failed to restore completely the altered DNA methylation status and prevent the progression of liver carcinogenesis. These results suggest that stable alterations in DNA methylation are a factor that promotes the progression of liver carcinogenesis. Additionally, the results indicate that epigenetic changes may be more reliable markers than DNA lesions of the carcinogenic process and carcinogen exposure.
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Affiliation(s)
- Igor P Pogribny
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA.
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