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Bataglini C, Ramos Mariano I, Azevedo SCF, Freire VN, Natali MRM, Dias Pedrosa MM, Peralta RM, Sa-Nakanishi AB, Bracht L, Ferreira Godoy VA, Bracht A, Comar JF. Insulin degludec and glutamine dipeptide modify glucose homeostasis and liver metabolism in diabetic mice undergoing insulin-induced hypoglycemia. J Appl Biomed 2021; 19:210-219. [PMID: 34907740 DOI: 10.32725/jab.2021.025] [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: 12/03/2020] [Accepted: 10/21/2021] [Indexed: 11/05/2022] Open
Abstract
This study investigated whether a 30-day co-treatment with 1 g/kg glutamine dipeptide (GdiP) and 1 U/kg regular (rapid acting) or 5 U/kg degludec (long acting) insulins modifies glucose homeostasis and liver metabolism of alloxan-induced type 1 diabetic (T1D) male Swiss mice undergoing insulin-induced hypoglycemia (IIH). Glycemic curves were measured in fasted mice after IIH with 1 U/kg regular insulin. One hour after IIH, the lipid profile and AST and ALT activities were assayed in the serum. Morphometric analysis was assessed in the liver sections stained with hematoxylin-eosin and glycolysis, glycogenolysis, gluconeogenesis and ureagenesis were evaluated in perfused livers. T1D mice receiving GdiP or the insulins had a smaller blood glucose drop at 60 minutes after IIH, which was not sustained during the subsequent period up to 300 minutes. The 30-day treatment of T1D mice with insulin degludec, but not with regular insulin, improved fasting glycemia, body weight gain and serum activity of AST and ALT. Treatments with insulin degludec, GdiP and insulin degludec + GdiP decreased the liver capacity in synthesizing glucose from alanine. GdiP, in combination with both insulins, was associated with increases in the serum triglycerides and, in addition, regular insulin and GdiP increased AST and ALT activities, which could be the consequence of hepatic glycogen overload. GdiP and the insulins improved the IIH, although to a small extent. Caution is recommended, however, with respect to the use of GdiP because of its increasing effects on serum triglycerides and AST plus ALT activities.
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Affiliation(s)
- Camila Bataglini
- State University of Maringa, Department of Biochemistry, Maringa, PR, Brazil
| | - Isabela Ramos Mariano
- State University of Maringa, Department of Physiological Sciences, Maringa, PR, Brazil
| | | | | | | | | | | | | | - Livia Bracht
- State University of Maringa, Department of Biochemistry, Maringa, PR, Brazil
| | | | - Adelar Bracht
- State University of Maringa, Department of Biochemistry, Maringa, PR, Brazil
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2
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Assessment of genotoxic chemicals using chemogenomic profiling based on gene-knockout library in Saccharomyces cerevisiae. Toxicol In Vitro 2021; 79:105278. [PMID: 34843885 DOI: 10.1016/j.tiv.2021.105278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/19/2021] [Accepted: 11/23/2021] [Indexed: 02/07/2023]
Abstract
Understanding the adverse effects of genotoxic chemicals and identifying them effectively from non-genotoxic chemicals are of great worldwide concerns. Here, Saccharomyces cerevisiae (yeast) genome-wide single-gene knockout screening approach was conducted to assess two genotoxic chemicals (4-nitroquinoline-1-oxide (4-NQO) and formaldehyde (FA)) and environmental pollutant dichloroacetic acid (DCA, genotoxicity is controversial). DNA repair was significant enriched in the gene ontology (GO) biology process (BP) terms and KEGG pathways when exposed to low concentrations of 4-NQO and FA. Higher concentrations of 4-NQO and FA influenced some RNA metabolic and biosynthesis pathways. Moreover, replication and repair associated pathways were top ranked KEGG pathways with high fold-change for low concentrations of 4-NQO and FA. The similar gene profiles perturbed by DCA with three test concentrations identified, the common GO BP terms associated with aromatic amino acid family biosynthetic process and ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway. DCA has no obvious genotoxicity as there was no enriched DNA damage and repair pathways and fold-change of replication and repair KEGG pathways were very low. Five genes (RAD18, RAD59, MUS81, MMS4, and BEM4) could serve as candidate genes for genotoxic chemicals. Overall, the yeast functional genomic profiling showed great performance for assessing the signatures and potential molecular mechanisms of genotoxic chemicals.
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Stakišaitis D, Juknevičienė M, Damanskienė E, Valančiūtė A, Balnytė I, Alonso MM. The Importance of Gender-Related Anticancer Research on Mitochondrial Regulator Sodium Dichloroacetate in Preclinical Studies In Vivo. Cancers (Basel) 2019; 11:cancers11081210. [PMID: 31434295 PMCID: PMC6721567 DOI: 10.3390/cancers11081210] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/16/2019] [Accepted: 08/16/2019] [Indexed: 12/28/2022] Open
Abstract
Sodium dichloroacetate (DCA) is an investigational medicinal product which has a potential anticancer preparation as a metabolic regulator in cancer cells’ mitochondria. Inhibition of pyruvate dehydrogenase kinases by DCA keeps the pyruvate dehydrogenase complex in the active form, resulting in decreased lactic acid in the tumor microenvironment. This literature review displays the preclinical research data on DCA’s effects on the cell pyruvate dehydrogenase deficiency, pyruvate mitochondrial oxidative phosphorylation, reactive oxygen species generation, and the Na+–K+–2Cl− cotransporter expression regulation in relation to gender. It presents DCA pharmacokinetics and the hepatocarcinogenic effect, and the safety data covers the DCA monotherapy efficacy for various human cancer xenografts in vivo in male and female animals. Preclinical cancer researchers report the synergistic effects of DCA combined with different drugs on cancer by reversing resistance to chemotherapy and promoting cell apoptosis. Researchers note that female and male animals differ in the mechanisms of cancerogenesis but often ignore studying DCA’s effects in relation to gender. Preclinical gender-related differences in DCA pharmacology, pharmacological mechanisms, and the elucidation of treatment efficacy in gonad hormone dependency could be relevant for individualized therapy approaches so that gender-related differences in treatment response and safety can be proposed.
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Affiliation(s)
- Donatas Stakišaitis
- Laboratory of Molecular Oncology, National Cancer Institute, 08660 Vilnius, Lithuania.
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania.
| | - Milda Juknevičienė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Eligija Damanskienė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Angelija Valančiūtė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Ingrida Balnytė
- Department of Histology and Embryology, Medical Academy, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Marta Maria Alonso
- Department of Pediatrics, Clínica Universidad de Navarra, University of Navarra, 55 Pamplona, Spain.
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Asaoka Y, Togashi Y, Mutsuga M, Imura N, Miyoshi T, Miyamoto Y. Histopathological image analysis of chemical-induced hepatocellular hypertrophy in mice. ACTA ACUST UNITED AC 2016; 68:233-9. [DOI: 10.1016/j.etp.2015.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 12/11/2015] [Accepted: 12/15/2015] [Indexed: 11/27/2022]
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5
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Sapone A, Canistro D, Vivarelli F, Paolini M. Perturbation of xenobiotic metabolism in Dreissena polymorpha model exposed in situ to surface water (Lake Trasimene) purified with various disinfectants. CHEMOSPHERE 2016; 144:548-554. [PMID: 26397472 DOI: 10.1016/j.chemosphere.2015.09.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/21/2015] [Accepted: 09/06/2015] [Indexed: 06/05/2023]
Abstract
Sanitation is of crucial importance for the microbiological safety of drinking water. However, chlorination of water rich in organic material produces disinfection by-products (DBPs), many of which have been reported to be mutagenic and/or carcinogenic compounds such as haloacetic acids and trihalomethanes. Epidemiological studies have suggested a link between drinking water consumption and cancer. We previously observed that Cyprinus carpio fish exposed to DBPs, may be subject to epigenetic effects such as those referable to the up-regulation of cytochrome P450 (CYP) superfamily (ex. co-mutagenesis/co-carcinogenesis and oxidative stress) that has been associated to non-genotoxic carcinogenesis. Our goal was to study the xenobiotic metabolism in mollusks exposed in situ to surface water of Lake Trasimene (Central Italy) treated with several disinfectants such as the traditional chlorine dioxide (ClO2), sodium hypochlorite (NaClO) or the relatively new one peracetic acid (PAA). The freshwater bivalves (Dreissena polymorpha) being selected as biomarker, have the unique ability to accumulate pollutants. Freshwater bivalves were maintained in surface water containing each disinfectant individually (1-2 mg/L). Following an exposure period up to 20 days during the fall period, microsomes were collected from the mussels, then tested for various monooxygenases. Strong CYP inductions were observed. These data indicate that drinking water disinfection generates harmful DBP mixtures capable of determining a marked perturbation of CYP-supported reactions. This phenomenon, being associated to an increased pro-carcinogen bioactivation and persistent oxidative stress, could provide an explanation for the observational studies connecting the regular consumption of drinking water to increased risk of various cancers in humans.
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Affiliation(s)
- Andrea Sapone
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Via Irnerio, 48, 40126 Bologna, Italy
| | - Donatella Canistro
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Via Irnerio, 48, 40126 Bologna, Italy.
| | - Fabio Vivarelli
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Via Irnerio, 48, 40126 Bologna, Italy
| | - Moreno Paolini
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum, University of Bologna, Via Irnerio, 48, 40126 Bologna, Italy
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El Arem A, Ghrairi F, Lahouar L, Thouri A, Saafi EB, Ayed A, Zekri M, Ferjani H, Haouas Z, Zakhama A, Achour L. Hepatoprotective activity of date fruit extracts against dichloroacetic acid-induced liver damage in rats. J Funct Foods 2014. [DOI: 10.1016/j.jff.2014.04.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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Wood CE, Jokinen MP, Johnson CL, Olson GR, Hester S, George M, Chorley BN, Carswell G, Carter JH, Wood CR, Bhat VS, Corton JC, DeAngelo AB. Comparative time course profiles of phthalate stereoisomers in mice. Toxicol Sci 2014; 139:21-34. [PMID: 24496636 DOI: 10.1093/toxsci/kfu025] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
More efficient models are needed to assess potential carcinogenicity hazard of environmental chemicals based on early events in tumorigenesis. Here, we investigated time course profiles for key events in an established cancer mode of action. Using a case study approach, we evaluated two reference phthalates, di(2-ethylhexyl) phthalate (DEHP) and its stereoisomer di-n-octyl phthalate (DNOP), across the span of a two-year carcinogenicity bioassay. Male B6C3F1 mice received diets with no phthalate added (control), DEHP at 0.12, 0.60, or 1.20%, or DNOP at 0.10, 0.50, or 1.00% (n = 80-83/group) for up to 104 weeks with six interim evaluations starting at week 4. Mean phthalate doses were 139, 845, and 3147 mg/kg/day for DEHP and 113, 755, and 1281 mg/kg/day for DNOP groups, respectively. Incidence and number of hepatocellular tumors (adenoma and/or carcinoma) were greater at ≥ 60 weeks for all DEHP groups with time and dose trends, whereas DNOP had no significant effects. Key events supported a peroxisome proliferator-activated receptor alpha (PPARα) mode of action for DEHP, with secondary cytotoxicity at the high dose, whereas DNOP induced modest increases in PPARα activity without proliferative or cytotoxic effects. Threshold estimates for later tumorigenic effects were identified at week 4 for relative liver weight (+24%) and PPARα activity (+79%) relative to the control group. Benchmark doses (BMDs) for these measures at week 4 clearly distinguished DEHP and DNOP and showed strong concordance with values at later time points and tumorigenic BMDs. Other target sites included testis and kidney, which showed degenerative changes at higher doses of DEHP but not DNOP. Our results highlight marked differences in the chronic toxicity profiles of structurally similar phthalates and demonstrate quantitative relationships between early bioindicators and later tumor outcomes.
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Affiliation(s)
- Charles E Wood
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27709
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Corton JC. Evaluation of the role of peroxisome proliferator-activated receptor alpha (PPARalpha) in mouse liver tumor induction by trichloroethylene and metabolites. Crit Rev Toxicol 2009; 38:857-75. [PMID: 18821149 DOI: 10.1080/10408440802209796] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Trichloroethylene (TCE) is an industrial solvent and a widespread environmental contaminant. Induction of liver cancer in mice by TCE is thought to be mediated by two metabolites, dichloroacetate (DCA) and trichloroacetate (TCA), both of which are themselves mouse liver carcinogens. TCE, TCA, and DCA are relatively weak peroxisome proliferators (PP), a group of rodent hepatocarcinogens that activate a nuclear receptor, PP-activated receptor alpha (PPARalpha. The objective of this review is to assess the weight of evidence (WOE) that PPARalpha is or is not mechanistically involved in mouse liver tumor induction by TCE and metabolites. Based on similarities of TCE and TCA to typical PP, including dose-response characteristics showing PPARalpha-dependent responses coincident with liver tumor induction and abolishment of TCE and TCA effects in PPARalpha-null mice, the WOE supports the hypothesis that PPARalpha plays a dominant role in TCE- and TCA-induced hepatocarcinogenesis. Data indicates that the MOA for DCA tumor induction is PPARalpha-independent. Uncertainties remain regarding the genesis of the TCE-induced tumors. In contrast to the TCA-induced tumors, which have molecular features similar to those induced by typical PP, there is evidence, albeit weak, that TCE tumors arise by a mode of action (MOA) different from that of TCA tumors, based largely on dissimilarities in molecular markers found in TCE versus TCA-induced tumors. In summary, the WOE indicates that TCA-induced liver tumors arise by a PPARalpha-dependent MOA. Although the TCE MOA is likely dominated by a PPARalpha-dependent contribution from TCA, the contribution of a PPARalpha-independent MOA from DCA cannot be ruled out.
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Affiliation(s)
- J Christopher Corton
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
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9
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Clewell HJ, Andersen ME. Applying Mode-of-Action and Pharmacokinetic Considerations in Contemporary Cancer Risk Assessments: An Example with Trichloroethylene. Crit Rev Toxicol 2008; 34:385-445. [PMID: 15560567 DOI: 10.1080/10408440490500795] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The guidelines for carcinogen risk assessment recently proposed by the U.S. Environmental Protection Agency (U.S. EPA) provide an increased opportunity for the consideration of pharmacokinetic and mechanistic data in the risk assessment process. However, the greater flexibility of the new guidelines can also make their actual implementation for a particular chemical highly problematic. To illuminate the process of performing a cancer risk assessment under the new guidelines, the rationale for a state-of-the-science risk assessment for trichloroethylene (TCE) is presented. For TCE, there is evidence of increased cell proliferation due to receptor interaction or cytotoxicity in every instance in which tumors are observed, and most tumors represent an increase in the incidence of a commonly observed, species-specific lesion. A physiologically based pharmacokinetic (PBPK) model was applied to estimate target tissue doses for the three principal animal tumors associated with TCE exposure: liver, lung, and kidney. The lowest points of departure (lower bound estimates of the exposure associated with 10% tumor incidence) for lifetime human exposure to TCE were obtained for mouse liver tumors, assuming a mode of action primarily involving the mitogenicity of the metabolite trichloroacetic acid (TCA). The associated linear unit risk estimates for mouse liver tumors are 1.5 x 10(-6) for lifetime exposure to 1 microg TCE per cubic meter in air and 0.4 x 10(-6) for lifetime exposure to 1 microg TCE per liter in drinking water. However, these risk estimates ignore the evidence that the human is likely to be much less responsive than the mouse to the carcinogenic effects of TCA in the liver and that the carcinogenic effects of TCE are unlikely to occur at low environmental exposures. Based on consideration of the most plausible carcinogenic modes of action of TCE, a margin-of-exposure (MOE) approach would appear to be more appropriate. Applying an MOE of 1000, environmental exposures below 66 microg TCE per cubic meter in air and 265 microg TCE per liter in drinking water are considered unlikely to present a carcinogenic hazard to human health.
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10
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König R, Cai P, Guo X, Ansari GAS. Transcriptomic analysis reveals early signs of liver toxicity in female MRL +/+ mice exposed to the acylating chemicals dichloroacetyl chloride and dichloroacetic anhydride. Chem Res Toxicol 2008; 21:572-82. [PMID: 18293905 DOI: 10.1021/tx7002728] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Dichloroacetyl chloride (DCAC) is a reactive metabolite of trichloroethene (TCE). TCE and its metabolites have been implicated in the induction of organ-specific and systemic autoimmunity, in the acceleration of autoimmune responses, and in the development of liver toxicity and hepatocellular carcinoma. In humans, effects of environmental toxicants are often multifactorial and detected only after long-term exposure. Therefore, we developed a mouse model to determine mechanisms by which DCAC and related acylating agents affect the liver. Autoimmune-prone female MRL +/+ mice were injected intraperitoneally with 0.2 mmol/kg of DCAC or dichloroacetic anhydride (DCAA) in corn oil twice weekly for six weeks. No overt liver pathology was detectable. Using microarray gene expression analysis, we detected changes in the liver transcriptome consistent with inflammatory processes. Both acylating toxicants up-regulated the expression of acute phase response and inflammatory genes. Furthermore, metallothionein genes were strongly up-regulated, indicating effects of the toxicants on zinc ion homeostasis and stress responses. In addition, DCAC and DCAA induced the up-regulation of several genes indicative of tumorigenesis. Our data provide novel insight into early mechanisms for the induction of liver disease by acylating agents. The data also demonstrate the power of microarray analysis in detecting early changes in liver function following exposure to environmental toxicants.
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Affiliation(s)
- Rolf König
- Department of Microbiology & Immunology, The University of Texas Medical Branch, Galveston, Texas 77555, USA.
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11
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DeAngelo AB, Daniel FB, Wong DM, George MH. The induction of hepatocellular neoplasia by trichloroacetic acid administered in the drinking water of the male B6C3F1 mouse. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2008; 71:1056-68. [PMID: 18569617 DOI: 10.1080/15287390802111952] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The prevalence (percent of animals with a tumor) and multiplicity (number of tumors per animal) of hepatocellular neoplasia in the male B6C3F1 mouse exposed to trichloroacetic acid (TCA) in the drinking water were determined. Male mice were exposed to 0.05, 0.5, and 5 g/L TCA for 60 wk (Study 1), to 4.5 g/L TCA for 104 wk (Study 2) and to 0.05 and 0.5 g/L TCA for 104 wk (Study 3). Time-weighted mean daily doses measured for the low, medium, and high dose groups were consistent over the three studies, 6-8, 58-68, and 572-602 mg/kg-d for the 0.05, 0.5, and the 4.5-5 g/L treatment groups, respectively. No significant changes in animal survival were noted across the studies. A significant increase in the prevalence and multiplicity of hepatocellular tumors was found in the 58-68 and 572-602 mg/kg/d TCA dose groups. Nonhepatoproliferative changes (cytoplasmic alterations, inflammation, and necrosis) in mice treated with TCA were mild and dose related. A TCA-induced increase in liver palmitoyl CoA oxidase activity, a marker of peroxisome proliferation, correlated with tumor induction. A linear association was found between peroxisome proliferation and tumor induction. Sporadic increases in the labeling index of nuclei outside of proliferative lesions were observed at carcinogenic doses throughout the studies. Given that there are no compelling data demonstrating genotoxic activity of either TCA or any metabolite, data are consistent with an epigenetic mode of action. The studies provide dose-response data on the development of hepatocellular neoplasia in male mice over a lifetime exposure to TCA. A no-observed-effect-level (NOEL) of 6 mg/kg/d was calculated for neoplastic and nonproliferative liver pathology.
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Affiliation(s)
- Anthony B DeAngelo
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27709, USA.
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12
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Walgren JL, Kurtz DT, McMillan JM. Lack of direct mitogenic activity of dichloroacetate and trichloroacetate in cultured rat hepatocytes. Toxicology 2005; 211:220-30. [PMID: 15925025 DOI: 10.1016/j.tox.2005.03.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2004] [Revised: 03/14/2005] [Accepted: 03/16/2005] [Indexed: 11/30/2022]
Abstract
Dichloroacetate (DCA) and trichloroacetate (TCA) are hepatocarcinogenic metabolites of the common groundwater contaminant, 1,1,2-trichloroethylene. DCA and TCA have been shown to induce hepatocyte proliferation in vivo, but it is not known if this response is the result of direct mitogenic activity or whether cell replication occurs indirectly in response to tissue injury or inflammation. In this study we used primary cultures of rat hepatocytes, a species susceptible to DCA- but not TCA-induced hepatocarcinogenesis, to determine whether DCA and TCA are direct hepatocyte mitogens. Rat hepatocytes, cultured in growth factor-free medium, were treated with 0.01-1.0 mM DCA or TCA for 10-40 h; cell replication was then assessed by measuring incorporation of 3H-thymidine into DNA and by cell counts. DCA or TCA treatment did not alter 3H-thymidine incorporation in the cultured hepatocytes. Although an increase in cell number was not observed, DCA treatment significantly abrogated the normal background cell loss, suggesting an ability to inhibit apoptotic cell death in primary hepatocyte cultures. Furthermore, treatment with DCA synergistically enhanced the mitogenic response to epidermal growth factor. The data indicate that DCA and TCA are not direct mitogens in hepatocyte cultures, which is of interest in view of their ability to stimulate hepatocyte replication in vivo. Nevertheless, the synergistic enhancement of epidermal growth factor-induced hepatocyte replication by DCA is of particular interest and warrants further study.
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Affiliation(s)
- Jennie L Walgren
- Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, 171 Ashley Avenue, P.O. Box 250505, Charleston, SC 29425, USA.
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Lantum HBM, Baggs RB, Krenitsky DM, Board PG, Anders MW. Immunohistochemical localization and activity of glutathione transferase zeta (GSTZ1-1) in rat tissues. Drug Metab Dispos 2002; 30:616-25. [PMID: 12019185 DOI: 10.1124/dmd.30.6.616] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glutathione transferase zeta (GSTZ1-1) catalyzes the biotransformation of a range of alpha-haloacids, including dichloroacetic acid (DCA), and the penultimate step in the tyrosine degradation pathway. DCA is a rodent carcinogen and a common drinking water contaminant. DCA also causes multiorgan toxicity in rodents and dogs. The objective of this study was to determine the expression and activities of GSTZ1-1 in rat tissues with maleylacetone and chlorofluoroacetic acid as substrates. GSTZ1-1 protein was detected in most tissues by immunoblot analysis after immunoprecipitation of GSTZ1-1 and by immunohistochemical analysis; intense staining was observed in the liver, testis, and prostate; moderate staining was observed in the brain, heart, pancreatic islets, adrenal medulla, and the epithelial lining of the gastrointestinal tract, airways, and bladder; and sparse staining was observed in the renal juxtaglomerular regions, skeletal muscle, and peripheral nerve tissue. These patterns of expression corresponded to GSTZ1-1 activities in the different tissues with maleylacetone and chlorofluoroacetic acid as substrates. Specific activities ranged from 258 +/- 17 (liver) to 1.1 +/- 0.4 (muscle) nmol/min/mg of protein with maleylacetone as substrate and from 4.6 +/- 0.89 (liver) to 0.09 +/- 0.01 (kidney) nmol/min/mg of protein with chlorofluoroacetic acid as substrate. Rats given DCA had reduced amounts of immunoreactive GSTZ1-1 protein and activities of GSTZ1-1 in most tissues, especially in the liver. These findings indicate that the DCA-induced inactivation of GSTZ1-1 in different tissues may result in multiorgan disorders that may be associated with perturbed tyrosine metabolism.
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Affiliation(s)
- Hoffman B M Lantum
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York 14642, USA
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Kato-Weinstein J, Stauber AJ, Orner GA, Thrall BD, Bull RJ. Differential effects of dihalogenated and trihalogenated acetates in the liver of B6C3F1 mice. J Appl Toxicol 2001; 21:81-9. [PMID: 11288130 DOI: 10.1002/jat.717] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Haloacetates are produced in the chlorination of drinking water in the range 10--100 microg l(-1). As bromide concentrations increase, brominated haloacetates such as bromodichloroacetate (BDCA), bromochloroacetate (BCA) and dibromoacetate (DBA) appear at higher concentrations than the chlorinated haloacetates: dichloroacetate (DCA) or trichloroacetate (TCA). Both DCA and TCA differ in their hepatic effects; TCA produces peroxisome proliferation as measured by increases in cyanide-insensitive acyl CoA oxidase activity, whereas DCA increases glycogen concentrations. In order to determine whether the brominated haloacetates DBA, BCA and BDCA resemble DCA or TCA more closely, mice were administered DBA, BCA and BDCA in the drinking water at concentrations of 0.2--3 g l(-1). Both BCA and DBA caused liver glycogen accumulation to a similar degree as DCA (12 weeks). The accumulation of glycogen occurred in cells scattered throughout the acinus in a pattern very similar to that observed in control mice. In contrast, TCA and low concentrations of BDCA (0.3 g l(-1)) reduced liver glycogen content, especially in the central lobular region. The high concentration of BDCA (3 g l(-1)) produced a pattern of glycogen distribution similar to that in DCA-treated and control mice. This effect with a high concentration of BDCA may be attributable to the metabolism of BDCA to DCA. All dihaloacetates reduced serum insulin levels. Conversely, trihaloacetates had no significant effects on serum insulin levels. Dibromoacetate was the only brominated haloacetate that consistently increased acyl-CoA oxidase activity and rates of cell replication in the liver. These results further distinguish the effects of the dihaloacetates from those of peroxisome proliferators like TCA.
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Affiliation(s)
- J Kato-Weinstein
- Pharmacology/Toxicology Program, College of Pharmacy, Washington State University, Pullman, WA 99164-6510, USA
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DeAngelo AB. Response to "Epigenetic mechanisms of chemical carcinogenesis" by James E. Klaunig, Lisa M. Kamendulis, and Xu Yong. Hum Exp Toxicol 2000; 19:561-2; discussion 571-2. [PMID: 11211993 DOI: 10.1191/096032700701546460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- A B DeAngelo
- National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
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HASEGAWA R, HIROSE A, NISHIKAWA A, KUREBAYASHI H, EMA M, KUROKAWA Y. Toxicity Evaluation of Dichloroacetic Acid and Estimation of the Tolerable Daily Intake through Oral Route. ACTA ACUST UNITED AC 1999. [DOI: 10.2965/jswe.22.821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Ryuichi HASEGAWA
- Biological Safety Research Center, National Institute of Health Sciences
| | - Akihiko HIROSE
- Biological Safety Research Center, National Institute of Health Sciences
| | - Akiyoshi NISHIKAWA
- Biological Safety Research Center, National Institute of Health Sciences
| | - Hideo KUREBAYASHI
- Biological Safety Research Center, National Institute of Health Sciences
| | - Makoto EMA
- Osaka Branch, National Institute of Health Sciences
| | - Yuji KUROKAWA
- Biological Safety Research Center, National Institute of Health Sciences
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Stauber AJ, Bull RJ, Thrall BD. Dichloroacetate and trichloroacetate promote clonal expansion of anchorage-independent hepatocytes in vivo and in vitro. Toxicol Appl Pharmacol 1998; 150:287-94. [PMID: 9653059 DOI: 10.1006/taap.1998.8417] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dichloroacetate (DCA) and trichloroacetate (TCA) are hepatocarcinogenic by-products of water chlorination and metabolites of several industrial solvents. To determine whether DCA and TCA promote the clonal expansion of anchorage-independent liver cells in vitro, a modification of the soft agar assay (over agar assay) was utilized to quantitate growth and analyze phenotype of anchorage-independent hepatocellular colonies. Hepatocytes from naïve male B6C3F1 mice were isolated and cultured with 0-2.0 mM DCA or TCA over agar for 10 days, at which time colonies of eight cells or more were scored. Both DCA and TCA promoted the formation of anchorage-independent colonies in a dose-dependent manner. Immunocytochemical analysis using a c-Jun antibody demonstrated that colonies promoted by DCA were primarily c-Jun+, whereas TCA-promoted colonies were primarily c-Jun-. This corresponds to the differences in c-Jun immunoreactivity reported in tumors induced by DCA and TCA. Neither DCA nor TCA induced c-Jun expression in hepatocyte monolayers, indicating that these haloacetates selectively affect subpopulations of anchorage-independent hepatocyts. The latency of colony formation was decreased by the concentration of DCA, although the same number of colonies appeared after 25 days in culture at all DCA concentrations used. The plating density of hepatocytes also affected colony formation. At lower cell densities, promotion of colony formation by DCA was significantly reduced. Pretreatment of male B6C3F1 mice with 0.5 g/liter DCA in drinking water resulted in a fourfold increase in in vitro colony formation above hepatocytes isolated from naïve mice, suggesting that DCA is promoting the clonal expansion of anchorage-independent hepatocytes in vivo. Results from this study indicate that DCA and TCA promote the survival and growth of initiated cells. Furthermore, results from over agar assays reflect observations made in vivo, indicating this assay provides a valid means to investigate the mechanism by which chemicals promote clonal expansion of initiated hepatocytes.
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Affiliation(s)
- A J Stauber
- Pharmacology/Toxicology Graduate Program, Washington State University, Pullman, USA
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McHugh Law J, Lopez L, DeAngelo AB. Hepatotoxicity of the drinking water disinfection by-product, dichloroacetic acid, in the medaka small fish model. Toxicol Lett 1998; 94:19-27. [PMID: 9544695 DOI: 10.1016/s0378-4274(97)00095-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recent studies have shown that dichloroacetic acid (DCA), a by-product of chlorination of public water supplies, is carcinogenic to both rats and mice. However, conflicting data have left the mechanism of DCA carcinogenicity, vital to assessment of human health risk, unclear. Elucidation of this mechanism in another animal model at a different phyletic level than rodents would advance the risk assessment process for government agencies concerned with regulation and provision of safe drinking water. The Japanese medaka (Oryzias latipes), a well characterized small fish model, is being used increasingly for carcinogenicity testing because of its low cost, ease of maintenance and carcinogen sensitivity. In this study, 6-week-old medaka were exposed to diethylnitrosamine (DEN, a known initiator), followed by continuous exposure to 0.5 or 2.0 g/l DCA in the ambient water, over a 4 week period. At both exposure concentrations, changes in the liver included marked hepatocellular cytoplasmic vacuolation, cytomegaly, karyomegaly, nuclear atypia and multifocal areas of hepatocellular necrosis and loss as early as week two of DCA exposure. The majority of the hepatocellular cytoplasmic vacuoles were shown by periodic acid Schiff (PAS) staining to contain large amounts of glycogen. These elevated glycogen levels may reflect a disruption in the enzyme pathways for glycolysis. The total cellular changes seen in this short-term exposure regimen are compatible with preneoplastic changes seen in rats and mice exposed to DCA. The results of this study strengthen the role of the Japanese medaka as a suitable species in carcinogenicity testing as well as its implementation in the risk assessment process for DCA across several phyletic levels.
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Affiliation(s)
- J McHugh Law
- Department of Microbiology, Pathology and Parasitology, North Carolina State University, College of Veterinary Medicine, Raleigh 27606, USA
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