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Pickles JC, Pant K, Mcginty LA, Yasaei H, Roberts T, Scott AD, Newbold RF. A mechanistic evaluation of the Syrian hamster embryo cell transformation assay (pH 6.7) and molecular events leading to senescence bypass in SHE cells. Mutat Res Genet Toxicol Environ Mutagen 2016; 802:50-8. [PMID: 27169376 PMCID: PMC4877681 DOI: 10.1016/j.mrgentox.2016.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 04/01/2016] [Accepted: 04/01/2016] [Indexed: 12/19/2022]
Abstract
The implementation of the Syrian hamster embryo cell transformation assay (SHE CTA) into test batteries and its relevance in predicting carcinogenicity has been long debated. Despite prevalidation studies to ensure reproducibility and minimise the subjective nature of the assay's endpoint, an underlying mechanistic and molecular basis supporting morphological transformation (MT) as an indicator of carcinogenesis is still missing. We found that only 20% of benzo(a)pyrene-induced MT clones immortalised suggesting that, alone, the MT phenotype is insufficient for senescence bypass. From a total of 12 B(a)P- immortalised MT lines, inactivating p53 mutations were identified in 30% of clones, and the majority of these were consistent with the potent carcinogen's mode of action. Expression of p16 was commonly silenced or markedly reduced with extensive promoter methylation observed in 45% of MT clones, while Bmi1 was strongly upregulated in 25% of clones. In instances where secondary events to MT appeared necessary for senescence bypass, as evidenced by a transient cellular crisis, clonal growth correlated with monoallelic deletion of the CDKN2A/B locus. The findings further implicate the importance of p16 and p53 pathways in regulating senescence while providing a molecular evaluation of SHE CTA -derived variant MT clones induced by benzo(a)pyrene.
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Affiliation(s)
- Jessica C Pickles
- Institute of Cancer Genetics and Pharmacogenomics, Brunel University London, Kingston Lane, Uxbridge, Middlesex UB8 3PH, United Kingdom.
| | - Kamala Pant
- BioReliance Corporation, 14920 Broschart Road, Rockville, MD 20850-3349, USA
| | - Lisa A Mcginty
- Institute of Cancer Genetics and Pharmacogenomics, Brunel University London, Kingston Lane, Uxbridge, Middlesex UB8 3PH, United Kingdom
| | - Hemad Yasaei
- Institute of Cancer Genetics and Pharmacogenomics, Brunel University London, Kingston Lane, Uxbridge, Middlesex UB8 3PH, United Kingdom
| | - Terry Roberts
- Institute of Cancer Genetics and Pharmacogenomics, Brunel University London, Kingston Lane, Uxbridge, Middlesex UB8 3PH, United Kingdom
| | - Andrew D Scott
- Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedford MK44 1LQ, United Kingdom
| | - Robert F Newbold
- Institute of Cancer Genetics and Pharmacogenomics, Brunel University London, Kingston Lane, Uxbridge, Middlesex UB8 3PH, United Kingdom.
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Maire MA, Pant K, Poth A, Schwind KR, Rast C, Bruce SW, Sly JE, Kunz-Bohnenberger S, Kunkelmann T, Engelhardt G, Schulz M, Vasseur P. Prevalidation study of the Syrian hamster embryo (SHE) cell transformation assay at pH 7.0 for assessment of carcinogenic potential of chemicals. Mutation Research/Genetic Toxicology and Environmental Mutagenesis 2012; 744:64-75. [DOI: 10.1016/j.mrgentox.2011.12.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 12/09/2011] [Indexed: 11/16/2022]
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Ahmadzai AA, Trevisan J, Pang W, Patel II, Fullwood NJ, Bruce SW, Pant K, Carmichael PL, Scott AD, Martin FL. Classification of test agent-specific effects in the Syrian hamster embryo assay (pH 6.7) using infrared spectroscopy with computational analysis. Mutagenesis 2012; 27:375-82. [DOI: 10.1093/mutage/ges003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Maire MA, Pant K, Phrakonkham P, Poth A, Schwind KR, Rast C, Bruce SW, Sly JE, Bohnenberger S, Kunkelmann T, Schulz M, Vasseur P. Recommended protocol for the Syrian hamster embryo (SHE) cell transformation assay. Mutat Res 2012; 744:76-81. [PMID: 22198328 DOI: 10.1016/j.mrgentox.2011.12.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 12/09/2011] [Indexed: 11/24/2022]
Abstract
The Syrian hamster embryo (SHE) cell transformation assay (CTA) is a short-term in vitro assay recommended as an alternative method for testing the carcinogenic potential of chemicals. SHE cells are "normal" cells since they are diploid, genetically stable, non-tumourigenic, and have metabolic capabilities for the activation of some classes of carcinogens. The CTA, first developed in the 1960s by Berwald and Sachs (1963,1964) [3,4], is based on the change of the phenotypic feature of cell colonies expressing the first steps of the conversion of normal to neoplastic-like cells with oncogenic properties. Pienta et al. (1977) [22] developed a protocol using cryopreserved cells to enhance practicality of the assay and limit sources of variability. Several variants of the assay are currently in use, which mainly differ by the pH at which the assay is performed. We present here the common version of the SHE pH 6.7 CTA and SHE pH 7.0 CTA protocols used in the ECVAM (European Centre for the Validation of Alternative Methods) prevalidation study on CTA reported in this issue. It is recommended that this protocol, in combination with the photo catalogues presented in this issue, should be used in the future and serve as a basis for the development of the OECD test guideline.
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Ahmadzai AA, Trevisan J, Fullwood NJ, Carmichael PL, Scott AD, Martin FL. The Syrian hamster embryo (SHE) assay (pH 6.7): mechanisms of cell transformation and application of vibrational spectroscopy to objectively score endpoint alterations. Mutagenesis 2011; 27:257-66. [DOI: 10.1093/mutage/ger086] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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Maire MA, Bazin E, Fessard V, Rast C, Humpage A, Vasseur P. Morphological cell transformation of Syrian hamster embryo (SHE) cells by the cyanotoxin, cylindrospermopsin. Toxicon 2010; 55:1317-22. [DOI: 10.1016/j.toxicon.2010.01.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 01/20/2010] [Accepted: 01/27/2010] [Indexed: 12/01/2022]
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Abstract
The causes of amyotrophic lateral sclerosis (ALS) are poorly understood. A small proportion, about 2%, is associated with a mutation in the superoxide dismutase (SOD1) gene, and mice expressing this mutant gene exhibit a progressive, ALS-like neurodegenerative disease. Studies of these animals, as well as of human post mortem tissue, reveal the presence of multiple pathological processes, including oxidative stress, glutamate excitotoxicity, neuroinflammation, mitochondrial degeneration, alterations in neurofilaments and neurotubules, mitochondrial damage, aggregation of proteins, abnormalities in growth factors, and apoptosis. We propose that alterations in the disposition of zinc ions may be important in the initiation and development of ALS. SOD1 binds zinc, and many of the mutant forms of this enzyme associated with ALS show altered zinc binding. Alterations in the expression of metallothioneins (MTs), which regulate cellular levels of zinc, have been reported in mutant SOD1 mice, and deletion of MTs in these animals accelerates disease progression. Zinc plays a key role in all the pathological processes associated with ALS. Our zinc hypothesis also may help explain evidence for environmental factors in some cases of ALS, such as in the Chamorro tribe in Guam and in the Gulf War.
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Affiliation(s)
- Andrew P Smith
- The Forbes Norris ALS Research Center, California Pacific Medical Center Research Institute, California 94115, USA
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Prasad S, Kalra N, Srivastava S, Shukla Y. Regulation of oxidative stress–mediated apoptosis by diallyl sulfide in DMBA-exposed Swiss mice. Hum Exp Toxicol 2008; 27:55-63. [DOI: 10.1177/0960327108088978] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Diallyl sulfide, a sulfur-containing volatile compound present in garlic ( Allium sativum), exerts anticarcinogenic activity in various rodent tumor models. In the present study, apoptosis-inhibiting effects of diallyl sulfide against a carcinogenic polycyclic aromatic hydrocarbon, 7,12-dimethyl benz(a)anthracene (DMBA), in Swiss albino mice were observed. The animals were given either 250 μg/mouse or 500 μg/mouse of diallyl sulfide for 1 week after a single intragastric dose of 7,12-dimethyl benz(a)anthracene (50 mg/kg body weight). Results showed that diallyl sulfide supplementation effectively protects against 7,12-dimethyl benz(a)anthracene—induced oxidative stress, characterized by restored antioxidant enzyme levels (up to 64%) and lipid peroxidation (up to 25%). Flow cytometric analysis showed a reduction in apoptotic cell population in hypodiploid region in diallyl sulfide–supplemented animals. Inhibition of apoptosis was preceded by decrease in reactive oxygen species levels and restoration of mitochondrial transmembrane potential followed by decreased DNA fragmentation. In 7,12-dimethyl benz(a)anthracene–exposed animals, downregulation (~30%) of antiapoptotic Bcl-2 and upregulation (~60%) of pro-apoptotic Bax proteins were observed. These alterations were restored significantly by diallyl sulfide supplementation, indicating inhibition of apoptosis. Thus, these results show that diallyl sulfide provides protection against oxidative damage induced by 7,12-dimethyl benz(a)anthracene in mouse liver and may be an effective chemopreventive and therapeutic agent by modulating expression of cell-growth regulatory proteins.
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Affiliation(s)
- S Prasad
- Proteomics Laboratory, Indian Institute of Toxicology Research, Mahatma Gandhi Marg, Lucknow, India
| | - N Kalra
- Proteomics Laboratory, Indian Institute of Toxicology Research, Mahatma Gandhi Marg, Lucknow, India
| | - S Srivastava
- Proteomics Laboratory, Indian Institute of Toxicology Research, Mahatma Gandhi Marg, Lucknow, India
| | - Y Shukla
- Proteomics Laboratory, Indian Institute of Toxicology Research, Mahatma Gandhi Marg, Lucknow, India
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Maire MA, Rast C, Landkocz Y, Vasseur P. 2,4-Dichlorophenoxyacetic acid: effects on Syrian hamster embryo (SHE) cell transformation, c-Myc expression, DNA damage and apoptosis. Mutat Res 2007; 631:124-36. [PMID: 17540612 DOI: 10.1016/j.mrgentox.2007.03.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 01/16/2007] [Accepted: 03/23/2007] [Indexed: 11/25/2022]
Abstract
2,4-Dichlorophenoxyacetic acid (2,4-D) is a selective, systemic auxin-type herbicide extensively used throughout the world. The present research was aimed at studying effects of low and non-cytotoxic concentrations of 2,4-D on SHE cells in relation with carcinogenicity. Effects were studied on Syrian hamster morphological cell transformation, c-Myc expression - both at the gene and protein level - DNA damage and apoptosis. 2,4-D significantly induced cell transformation at 11.5 microM and 23 microM (i.e. 2.5 microg/mL and 5 microg/mL). An increase in the expression of the transcription factor c-Myc, measured by use of RT-PCR with respect to mRNA level and by Western blotting for protein level was registered at these concentrations, as well as genotoxic effects evaluated with the single-cell gel electrophoresis (Comet) assay. Consequences for apoptosis of 2,4-D treatment were also investigated. The fluorochrome acridine orange was used to study DNA fragmentation as a marker of apoptosis. No effect on apoptosis was found at 2,4-D concentrations that induced cell transformation. This was confirmed by the unchanged expression of Bcl-2 and Bax, two regulator genes of the mitochondrial pathway of apoptosis. Our results demonstrate the transforming and genotoxic effects of low concentrations of 2,4-D in mammalian cells. This information contributes to a better understanding of the mechanism of 2,4-D toxicity in mammalian cells and demonstrates that 2,4-D should be considered as potentially hazardous to humans.
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Affiliation(s)
- M A Maire
- Laboratoire Ecotoxicité Santé Environnementale, CNRS UMR 7146, Université de Metz, UFR Sciences Fondamentales et Appliquées, Rue Général Delestraint, 57070 Metz, France
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Maire MA, Rast C, Vasseur P. Di-(2-ethylhexyl)phthalate (DEHP) increases Bcl-2/Bax ratio and modifies c-myc expression in Syrian hamster embryo (SHE) cells. Toxicol Lett 2005; 158:237-45. [PMID: 15923092 DOI: 10.1016/j.toxlet.2005.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Revised: 04/04/2005] [Accepted: 04/05/2005] [Indexed: 11/18/2022]
Abstract
The objective of this work was to study the anti-apoptotic properties of the non-genotoxic rodent carcinogen, di(2-ethylhexyl)phthalate (DEHP) in Syrian hamster embryo (SHE) cells. We demonstrated that a 24 h pre-treatment of SHE cells with 50 microM DEHP inhibited apoptosis triggered by growth factors deprivation. The RNA expression levels of the regulator genes involved in the apoptotic pathway, bcl-2, bax and of c-myc were measured using Western blotting and RT-PCR. We showed that a 24 h treatment of SHE cells with 50 microM DEHP increased (P < 0.05) the bcl-2 expression, while c-myc expression was decreased. No effect on bax expression was observed in the range of 10-50 microM. The defective regulation of apoptosis caused by DEHP treatment could contribute to its carcinogenicity.
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Affiliation(s)
- M A Maire
- ESE, Université de Metz, Faculté des Sciences, Campus Bridoux, rue du Général Delestraint, 57070 Metz, France.
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