1
|
Clark-Knowles KV, Dewar-Darch D, Jardine KE, Coulombe J, Daneshmand M, He X, McBurney MW. Modulating SIRT1 activity variously affects thymic lymphoma development in mice. Exp Cell Res 2018; 371:83-91. [PMID: 30059665 DOI: 10.1016/j.yexcr.2018.07.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 05/25/2018] [Accepted: 07/26/2018] [Indexed: 12/30/2022]
Abstract
SIRT1 is a protein deacetylase with a broad range of biological functions, many of which are known to be important in carcinogenesis, however much of the literature regarding the role of SIRT1 in cancer remains conflicting. In this study we assessed the effect of SIRT1 on the initiation and progression of thymic T cell lymphomas. We employed mouse strains in which SIRT1 activity was absent or could be reversibly modulated in conjunction with thymic lymphoma induction using either the N-nitroso-N-methylurea (NMU) carcinogenesis or the nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) transgene. Decreased SIRT1 activity reduced the development of thymic lymphomas in the NMU-treated mice but was permissive for the formation of lung adenomas. Conversely, in the NPM-ALK transgenic mice, decreased SIRT1 activity had a modest promoting effect in the development of thymic lymphomas. The results of the work presented here add to the growing body of evidence that sirt1 is neither an outright oncogene nor a tumor suppressor. These opposing results in two models of the same disease suggest that the influence of sirt1 on carcinogenesis may lie in a role in tumor surveillance.
Collapse
Affiliation(s)
| | - Danielle Dewar-Darch
- Centre for Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Canada.
| | - Karen E Jardine
- Centre for Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Canada.
| | - Josée Coulombe
- Centre for Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Canada.
| | - Manijeh Daneshmand
- Centre for Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Canada.
| | - Xiaohong He
- Centre for Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Canada.
| | - Michael W McBurney
- Centre for Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Canada; Department of Medicine, University of Ottawa, Ottawa, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada.
| |
Collapse
|
2
|
Thomas AD, Jenkins GJS, Kaina B, Bodger OG, Tomaszowski KH, Lewis PD, Doak SH, Johnson GE. Influence of DNA repair on nonlinear dose-responses for mutation. Toxicol Sci 2013; 132:87-95. [PMID: 23288051 PMCID: PMC3576011 DOI: 10.1093/toxsci/kfs341] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Recent evidence has challenged the default assumption that all DNA-reactive alkylating agents exhibit a linear dose-response. Emerging evidence suggests that the model alkylating agents methyl- and ethylmethanesulfonate and methylnitrosourea (MNU) and ethylnitrosourea observe a nonlinear dose-response with a no observed genotoxic effect level (NOGEL). Follow-up mechanistic studies are essential to understand the mechanism of cellular tolerance and biological relevance of such NOGELs. MNU is one of the most mutagenic simple alkylators. Therefore, understanding the mechanism of mutation induction, following low-dose MNU treatment, sets precedence for weaker mutagenic alkylating agents. Here, we tested MNU at 10-fold lower concentrations than a previous study and report a NOGEL of 0.0075 µg/ml (72.8nM) in human lymphoblastoid cells, quantified through the hypoxanthine (guanine) phosphoribosyltransferase assay (OECD 476). Mechanistic studies reveal that the NOGEL is dependent upon repair of O6-methylguanine (O6MeG) by the suicide enzyme O6MeG-DNA methyltransferase (MGMT). Inactivation of MGMT sensitizes cells to MNU-induced mutagenesis and shifts the NOGEL to the left on the dose axis.
Collapse
Affiliation(s)
- Adam D Thomas
- Institute of Life Science, College of Medicine, Swansea University, SA2 8PP, UK
| | | | | | | | | | | | | | | |
Collapse
|
3
|
Chang YC, Hsu JD, Lin WL, Lee YJ, Wang CJ. High incidence of acute promyelocytic leukemia specifically induced by N-nitroso-N-methylurea (NMU) in Sprague–Dawley rats. Arch Toxicol 2011; 86:315-27. [DOI: 10.1007/s00204-011-0753-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 09/14/2011] [Indexed: 10/17/2022]
|
4
|
Oghiso Y, Yamada Y. Pre-B-Cell Lymphomas in Mice Following Injection of 239Pu Citrate: Comparison with MNU-Induced T-Lymphoblastic Lymphomas. J Toxicol Pathol 2003. [DOI: 10.1293/tox.16.93] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Yoichi Oghiso
- Internal Radiation Effects Research Group, Research Center for Radiation Safety, National Institute of Radiological Sciences
| | - Yutaka Yamada
- Internal Radiation Effects Research Group, Research Center for Radiation Safety, National Institute of Radiological Sciences
| |
Collapse
|
5
|
Hemminki K, Koskinen M, Rajaniemi H, Zhao C. Dna adducts, mutations, and cancer 2000. Regul Toxicol Pharmacol 2000; 32:264-75. [PMID: 11162720 DOI: 10.1006/rtph.2000.1431] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The main achievements in the DNA adduct field in the 1990s have been technical innovations of methods for specific adducts reaching sensitivities required for low levels encountered in humans. Over 20 specific adducts or closely related groups of adducts have been determined in humans. The sources of the DNA-binding agents are endogenous and exogenous or both. In some of these studies adduct levels have been correlated to metabolic or DNA repair genotypes. An example of DNA adduct studies in human target tissue is taken on UV photoproducts in skin in situ. Adduct-induced mutations, specific mutation spectra, and their relationship to cancer are discussed. The quantitative adduct techniques will enable comparisons of endogenous and exogenous adduct levels and will give important clues to the etiology of human cancer. Furthermore, adducts will provide an intermediary tool for genotyping studies, both for metabolic enzyme and for DNA repair system genotypes. As the common polymorphisms are likely to cause at most moderate increases in the risk of cancer, the intermediary adduct endpoint is a necessary proof of causal relationships. The present and future biomonitoring studies will cover many endpoints to link the mechanistic steps from DNA adducts to cancer via mutations and modulating host susceptibility factors.
Collapse
Affiliation(s)
- K Hemminki
- Department of Biosciences, Karolinska Institute, Novum, Huddinge, 141 57, Sweden
| | | | | | | |
Collapse
|
6
|
Abstract
In this contribution we discuss the gene- and cell type-specific repair of miscoding DNA alkylation products as a risk parameter in both mutation induction and malignant transformation by N-nitroso carcinogens. Upon exposure to N-nitroso compounds such as N-methyl-N-nitrosourea (MeNU) or N-ethyl-N-nitrosourea (EtNU), about a dozen different alkylation products are formed in cellular DNA. Among these are O(6)-methylguanine (O(6)-MeGua) and O(6)-ethylguanine (O(6)-EtGua), respectively, which differ only by one CH(2) group in their alkyl residue and, when unrepaired, cause G:C-->A:T transition mutations by anomalous base pairing during DNA replication. We have analyzed the global and gene-specific repair of O(6)-MeGua and O(6)-EtGua in target cell DNA, ras gene mutation frequencies, and tumor incidence, in the model of mammary carcinogenesis induced in 50-day-old female Sprague-Dawley rats by a single application of MeNU or EtNU. Both carcinogens induce histologically indistinguishable mammary adenocarcinomas at high yield. In the target mammary epithelia, O(6)-MeGua is repaired at similar slow rates in both transcriptionally active genes (Ha-ras, beta-actin), silent genes (lgE heavy chain), and in bulk DNA, by the one-step repair protein O(6)-alkylguanine-DNA alkyltransferase (MGMT; low level of expression in the target cells). The slow repair of O(6)-MeGua translates into a high frequency of mutations at the central position of Ha-ras codon 12 (GGA) in MeNU-induced tumors. O(6)-EtGua, however, is removed approximately 20 times faster than O(6)-MeGua selectively from transcribed genes via an MGMT independent, as yet uncharacterized excision mechanism. Accordingly, no Ha-ras codon 12 mutations are found in the EtNU-induced mammary tumors. Neither MeNU- nor EtNU-induced tumors exhibit mutations at codons 13 and 61 of Ha-ras or at codons 12, 13 and 61 of Ki-ras. While a moderate surplus MGMT activity of the target cells - contributed by a bacterial MGMT transgene (ada) - significantly counteracts mammary tumorigenesis in MeNU-exposed rats, this is not the case in the EtNU-treated animals. Differential repair of structurally distinct DNA lesions in transcribed or (temporarily) silent genes thus determines the probability of mutation and, together with cell type-specific and interindividual differences in DNA repair capacity, influences carcinogenic risk.
Collapse
Affiliation(s)
- J Engelbergs
- Institute of Cell Biology (Cancer Research), University of Essen Medical School and West German Cancer Center Essen, Hufelandstrasse 55, D-45122, Essen, Germany
| | | | | |
Collapse
|
7
|
Karsunky H, Geisen C, Schmidt T, Haas K, Zevnik B, Gau E, Möröy T. Oncogenic potential of cyclin E in T-cell lymphomagenesis in transgenic mice: evidence for cooperation between cyclin E and Ras but not Myc. Oncogene 1999; 18:7816-24. [PMID: 10618723 DOI: 10.1038/sj.onc.1203205] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
To study the oncogenic activity of cyclin E in an in vivo system we generated transgenic mice expressing high levels of cyclin E in T-lymphocytes by using a construct containing the CD2 locus control region. These animals were neither predisposed to develop any tumors spontaneously nor showed an increased incidence when crossbred with Emu L-myc transgenic mice but developed hyperplasia in peripheral lymphoid organs at later age with an incidence of 27%. When treated with the DNA methylating carcinogen N-methylnitrosourea (MNU) that provokes the development of T-cell lymphomas, CD2-cyclin E transgenic animals came down with T-cell neoplasia showing a significant higher incidence (54%) than normal non transgenic controls (31%). In one of eight tumors that arose in normal MNU treated mice we could find an expected activating point mutation in the Ki-ras gene (12.5%). In contrast, the same mutation occurred in five of 16 tumors from CD2-cyclin E transgenic mice (31.2%). Whereas cyclin E overexpression alone did not lead to an increased CDK2 activity we observed in all tumors that emerged from either MNU treated normal mice or treated CD2-cyclin E transgenics a downregulation of p27KIP1 and a higher histone H1 kinase activity in CDK2 immunoprecipitates compared to normal tissue. These findings demonstrate that high level expression of cyclin E can predispose T-cells for hyperplasia and malignant transformation. However, the results also suggest that this activity of cyclin E is manifest only when other cooperating oncogenes in particular ras genes are present and activated. This would be consistent with our previous finding that cyclin E and Ha-Ras cooperate in focus formation assays in rat embryo fibroblasts.
Collapse
Affiliation(s)
- H Karsunky
- Institut für Zellbiologie (Tumorforschung), IFZ, Universitätsklinikum Essen, Virchowstrasse 173, D-45122 Essen, Germany
| | | | | | | | | | | | | |
Collapse
|
8
|
Abstract
Human exposure to methylating agents appears to be widespread, as indicated by the frequent occurrence of methylated DNA adducts in human DNA. The high incidence of methylated DNA adducts even in humans thought not to have suffered extensive exposure to environmental methylating agents implies that chemicals of endogenous origin, probably N-nitroso compounds such as the strongly carcinogenic N-nitrosodimethylamine (NDMA), may be primarily responsible for their formation and raises the question of the carcinogenic risks associated with such exposure. In addition to accumulation of DNA damage, other factors (such as induced cell proliferation) appear to be important in determining the probability of induction of mutation or cancer by NDMA, implying that high to low dose risk extrapolations should not be based on the assumption of dose- or even adduct-linearity. Comparative studies of the accumulation and repair of methylated adducts in humans and animals treated with methylating cytostatic drugs do not reveal significant species differences. Based on this and the dosimetry of adduct accumulation in rats chronically exposed to very low doses of NDMA, it is suggested that the exposure needed to account for the levels of adducts found in human DNA may be of the order of hundreds of micrograms NDMA (or equivalent) per day, a level of exposure which may well represent a significant carcinogenic hazard for man.
Collapse
Affiliation(s)
- S A Kyrtopoulos
- Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Avenue, Athens 11635, Greece
| |
Collapse
|
9
|
Cazorla M, Hernández L, Fernández PL, Fabra A, Peinado MA, Dasenbrock C, Tillmann T, Kamino K, Campo E, Kohler M, Morawieltz G, Cardesa A, Tomatis L, Mohr U. Ki-ras gene mutations and absence of p53 gene mutations in spontaneous and urethane-induced early lung lesions in CBA/J mice. Mol Carcinog 1998; 21:251-60. [PMID: 9585255 DOI: 10.1002/(sici)1098-2744(199804)21:4<251::aid-mc4>3.0.co;2-n] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Ki-ras and p53 genes are involved in human lung carcinogenesis; however, the role of these genes in experimental lung tumors is not well known. In our study, the CBA/J mouse strain was used to investigate the presence of Ki-ras and p53 alterations in lung carcinogenesis of spontaneous tumors and tumors induced with high and low doses of urethane (ethyl carbamate). To study the presence of these alterations in the early stages of lung carcinogenesis and in very small lung tumors, restriction fragment length polymorphism and single-strand conformation polymorphism analyses were performed on polymerase chain reaction-amplified DNA from microdissected tumoral and normal lung samples. Ki-ras gene mutations in codons 12 and 61 were detected in all types of lung lesions, even in small and preneoplastic lesions, and their incidence increased with progression from lung hyperplasias (18%) to adenomas (75%) and to carcinomas (80%). Urethane exposure, in both high and low doses, increased the incidence of Ki-ras mutations in lung tumors, especially in adenomas. The presence of Ki-ras gene mutations in very small urethane-induced lung tumors and the absence of hyperplasias among the treated-group lesions may indicate that urethane accelerates tumoral progression. No p53 mutations were detected in exons 5-8 in any of the epithelium-derived lung tumors. Only one p53 mutation in exon 5 was found in a spontaneous lymphoma. Therefore, p53 mutations do not seem to cooperate with Ki-ras gene mutations or represent an alternative molecular pathway in murine carcinogenesis.
Collapse
Affiliation(s)
- M Cazorla
- Department of Anatomic Pathology, Hospital Clínic Provincial, University of Barcelona, Spain
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Newcomb EW. Clonal evolution of N-methylnitrosourea-induced C57BL/6J thymic lymphomas by analysis of multiple genetic alterations. Leuk Res 1997; 21:189-98. [PMID: 9111162 DOI: 10.1016/s0145-2126(96)00060-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
C57BL/6J mice were treated with N-methylnitrosourea (NMU) and the evolution of leukemic T-cells clones into frank thymic lymphomas was followed in 42 animals using serology of T-cell markers, rearrangements of the T-cell receptor genes gamma, beta1 and beta2 and detection of carcinogen-induced Ki-ras mutations and trisomy of chromosome 15. During the latent period, multiple populations of T-cell clones were present in the thymus, many contained trisomy 15, but few had detectable Ki-ras mutations. Since most frank lymphomas consisted of a single T-cell clone with both a mutation of Ki-ras and trisomy 15, the results imply that these two events are critical for the evolution of T-cell clones from the preleukemic phase to a more malignant disease stage. Progression to frank lymphomas is coincident with changes in the expression pattern of the T-cell growth factor interleukin-2 receptor, which may play a role in the selection, expansion and thymus-independent growth of a T-cell clone.
Collapse
Affiliation(s)
- E W Newcomb
- Department of Pathology and Kaplan Comprehensive Cancer Center, New York University Medical Center, New York, U.S.A
| |
Collapse
|
11
|
Affiliation(s)
- P L Coletta
- Molecular Medicine Unit, University of Leeds, St. James's University Hospital, Leeds, U.K
| | | | | |
Collapse
|
12
|
Osaka M, Matsuo S, Koh T, Sugiyama T. Specific N-ras mutation in bone marrow within 48 H of 7,12-dimethylbenz[a]anthracene treatment in Huggins-Sugiyama rat leukemogenesis. Mol Carcinog 1996; 16:126-31. [PMID: 8688147 DOI: 10.1002/(sici)1098-2744(199607)16:3<126::aid-mc2>3.0.co;2-f] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
7,12-Dimethylbenz[a]anthracene (DMBA)-induced leukemias in Long-Evans rats consistently have an A --> T transversion at the second base of codon 61 in the N-ras gene. This mutation is also detected in the preleukemic stage. To determine when this specific N-ras mutation occurs in the early stages of leukemogenesis, we designed the mutant allele-specific amplification method, which was sensitive enough to detect one mutant cell among 10(6) normal cells. In the study reported here, N-ras mutation was found in bone-marrow cells 2 d after a single DMBA injection and thereafter throughout the preleukemic stage. These results show that DMBA induces a specific N-ras mutation soon after one DMBA injection and that this mutation is probably the first event in DMBA leukemogenesis.
Collapse
Affiliation(s)
- M Osaka
- Department of Pathology, Faculty of Medicine, Kyoto University, Japan
| | | | | | | |
Collapse
|
13
|
Malarkey DE, Maronpot RR. Polymerase chain reaction and in situ hybridization: applications in toxicological pathology. Toxicol Pathol 1996; 24:13-23. [PMID: 8839277 DOI: 10.1177/019262339602400104] [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: 02/02/2023]
Abstract
Polymerase chain reaction (PCR) and in situ hybridization (ISH) have revolutionized the study of genes and gene expression, and many of these molecular biology advances will greatly impact research in toxicological pathology. PCR is one of the most powerful tools in molecular biology and involves primer-mediated enzymatic in vitro amplification of specific target DNA sequences. Recent innovative methods utilizing PCR technology have been developed to detect mutations in neoplastic and small subpopulations of cells, to study biomarkers of genetic susceptibility and genes involved with carcinogen metabolism, to estimate mutation frequencies, to find novel genes induced by chemical exposure, and to characterize gene expression. ISH provides data on individual cells rather than an average of total cellular populations and allows analysis for heterogeneity. When combined with PCR, the sensitivity of ISH is elevated, and single-copy DNA sequences, single-base mutations, or low copies of messenger RNA (mRNA) can potentially be detected within individual cells. Herein are reviewed ISH- and PCR-based techniques such as single-strand conformation polymorphism analysis to detect point mutations, allelotypic analysis for loss of heterozygosity, differential display of mRNA to characterize gene expression, quantitative reverse transcriptase polymerase chain reaction, and in situ polymerase chain reaction with emphasis on current or potential applications in toxicological pathology. These new and evolving techniques offer tremendous potential in providing new insights into the molecular basis of toxicity and carcinogenesis.
Collapse
Affiliation(s)
- D E Malarkey
- Environmental Carcinogenesis Program, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
| | | |
Collapse
|