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Kostka T, Empl MT, Seiwert N, Geisen SM, Hoffmann P, Adam J, Seeger B, Shay JW, Christmann M, Sturla SJ, Fahrer J, Steinberg P. Repair of O6-carboxymethylguanine adducts by O6-methylguanine-DNA methyltransferase in human colon epithelial cells. Carcinogenesis 2021; 42:1110-1118. [PMID: 34115837 DOI: 10.1093/carcin/bgab049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/23/2021] [Accepted: 06/09/2021] [Indexed: 11/13/2022] Open
Abstract
The protein O6-methylguanine-DNA methyltransferase (MGMT) is able to repair the mutagenic O6-methylguanine adduct back to guanine. In this context, it may protect against colorectal cancer (CRC) formation associated with N-nitroso compounds. Such compounds may be endogenously formed by nitrosylation of amino acids, which can give rise to mutagenic O6-methylguanine (O6-MeG) and O6-carboxymethylguanine (O6-CMG) adducts. It is well-established that O6-MeG is repaired by MGMT. However, up to now, whether O6-CMG is repaired by this enzyme remains unresolved. Therefore, the aim of the present study was to analyze the fate of both types of O6-guanine adducts in the presence and absence of MGMT activity. To this end, MGMT activity was efficiently blocked by its chemical inhibitor O6-benzylguanine in human colon epithelial cells (HCEC). Exposure of cells to azaserine (AZA) caused significantly higher levels of both O6-MeG and O6-CMG adducts in MGMT-inhibited cells, with O6-CMG as the more abundant DNA lesion. Interestingly, MGMT inhibition did not result in higher levels of AZA-induced DNA strand breaks in spite of elevated DNA adduct levels. In contrast, MGMT inhibition significantly increased DNA strand break formation after exposure to temozolomide (TMZ), a drug that exclusively generates O6-MeG adducts. In line with this finding, the viability of the cells was moderately reduced by TMZ upon MGMT inhibition, whereas no clear effect was observed in cells treated with AZA. In conclusion, our study clearly shows that O6-CMG is repaired by MGMT in HCEC, thereby suggesting that MGMT might play an important role as a tumor suppressor in diet-mediated CRC.
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Affiliation(s)
- Tina Kostka
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany.,Institute of Food Science and Human Nutrition, Gottfried Wilhelm Leibniz University Hannover, 30167 Hannover, Germany
| | - Michael T Empl
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany
| | - Nina Seiwert
- Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Susanne M Geisen
- Department of Health Sciences and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Pascal Hoffmann
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany
| | - Janine Adam
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany
| | - Bettina Seeger
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany.,Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Markus Christmann
- Department of Toxicology, University Medical Center Mainz, 55131 Mainz, Germany
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Jörg Fahrer
- Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Pablo Steinberg
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, 30173 Hannover, Germany.,Max Rubner-Institut, Federal Research Institute of Nutrition and Food, 76131 Karlsruhe, Germany
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Opium Consumption and the Incidence of Cancer: Does Opium Account as an Emerging Risk Factor for Gastrointestinal Cancer? J Gastrointest Cancer 2018; 49:172-180. [PMID: 29362985 DOI: 10.1007/s12029-017-0050-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE Some epidemiological studies have shown an association between opium consumption and the incidence of gastrointestinal (GI) cancer. The present study was designed to investigate the effects of opium on the initiation of GI cancer in rats. METHODS Forty-five rats were randomly divided into three groups; each received different treatment for 40 weeks. The rats in group 1 received purified water, while animals in group 2 were treated with 5 mg/kg diethylnitrosamine (DEN) orally for 8 weeks and continued with purified water by the end of the experiment. The third experimental group received 300 mg/kg opium for 16 weeks and then continued with 50 mg/kg phenobarbital by the end of the 40th week. The growth of tumors in the treated groups was assessed by histological changes and the up/down expression of p53, cdkn1, cdk2, e-cdh, and n-cdh genes in different parts of GI tract. RESULTS Histological examinations revealed that DEN was able to induce the growth of tumor in GI tract as shown by active mitotic figure in different regions of GI system and hyperplasia of hepatocytes associated with infiltration of inflammatory cells, intestinal villous hypertrophy, and colorectal adenoma. There was also significant (p < 0.05) overexpression of p53, cdk2, and n-Cdh genes in different parts of digestive system in DEN-treated group. However, these pathological changes and the degradation of gene expression were not observed in the opium-treated group. CONCLUSION The results of this study suggest that the opium does not promote the initiation of cancer in GI tract.
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Sheth RA, Kunin A, Stangenberg L, Sinnamon M, Hung KE, Kucherlapati R, Mahmood U. In Vivo Optical Molecular Imaging of Matrix Metalloproteinase Activity following Celecoxib Therapy for Colorectal Cancer. Mol Imaging 2012. [DOI: 10.2310/7290.2012.00003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Rahul A. Sheth
- From the Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, and Departments of Genetics and Medicine, Harvard Medical School, Boston, MA, and the Department of Gastroenterology, Tufts Medical School, Boston, MA
| | - Alexandra Kunin
- From the Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, and Departments of Genetics and Medicine, Harvard Medical School, Boston, MA, and the Department of Gastroenterology, Tufts Medical School, Boston, MA
| | - Lars Stangenberg
- From the Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, and Departments of Genetics and Medicine, Harvard Medical School, Boston, MA, and the Department of Gastroenterology, Tufts Medical School, Boston, MA
| | - Mark Sinnamon
- From the Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, and Departments of Genetics and Medicine, Harvard Medical School, Boston, MA, and the Department of Gastroenterology, Tufts Medical School, Boston, MA
| | - Kenneth E. Hung
- From the Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, and Departments of Genetics and Medicine, Harvard Medical School, Boston, MA, and the Department of Gastroenterology, Tufts Medical School, Boston, MA
| | - Raju Kucherlapati
- From the Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, and Departments of Genetics and Medicine, Harvard Medical School, Boston, MA, and the Department of Gastroenterology, Tufts Medical School, Boston, MA
| | - Umar Mahmood
- From the Division of Nuclear Medicine and Molecular Imaging, Department of Radiology, Massachusetts General Hospital, and Departments of Genetics and Medicine, Harvard Medical School, Boston, MA, and the Department of Gastroenterology, Tufts Medical School, Boston, MA
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Abstract
OBJECTIVE Infection and inflammation play a role in carcinogenesis, and highly prevalent oral and dental diseases have been significantly linked to some types of cancer. This article reviews current literature in this area. MATERIALS AND METHODS Open literature review using the PubMed database and focused on publications from 2000 to 2010. RESULTS Numerous potential mechanisms are implicated in the oral disease/carcinogenesis paradigm, including infection- and inflammation-associated cell pathology and microbial carcinogen metabolism. Poor oral hygiene is associated with oral cancer, but there is also evidence of a possible link between oral or dental infections and malignancies in general. CONCLUSION Oral infections may trigger malignant transformation in tissues of the mouth and other organs. However, scientific evidence to date remains weak and further well-conducted studies are warranted before cancer can be properly added to the list of oral infection-related systemic diseases.
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Affiliation(s)
- J H Meurman
- Institute of Dentistry, University of Helsinki, Department of Oral and Maxillofacial Diseases, Helsinki University Central Hospital, Helsinki, Finland.
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Abstract
Although scientific knowledge in viral oncology has exploded in the 20th century, the role of bacteria as mediators of oncogenesis has been less well elucidated. Understanding bacterial carcinogenesis has become increasingly important as a possible means of cancer prevention. This review summarizes clinical, epidemiological, and experimental evidence as well as possible mechanisms of bacterial induction of or protection from malignancy.
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Gorham ED, Garland CF, Garland FC, Grant WB, Mohr SB, Lipkin M, Newmark HL, Giovannucci E, Wei M, Holick MF. Vitamin D and prevention of colorectal cancer. J Steroid Biochem Mol Biol 2005; 97:179-94. [PMID: 16236494 DOI: 10.1016/j.jsbmb.2005.06.018] [Citation(s) in RCA: 218] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Inadequate photosynthesis or oral intake of Vitamin D are associated with high incidence rates of colorectal cancer, but the dose-response relationship has not been adequately studied. METHODS Dose-response gradients from observational studies of Vitamin D intake and serum 25-hydroxyvitamin D were plotted as trend lines. The point on each linear trend line corresponding to an odds ratio of 0.50 provided the prediagnostic Vitamin D intake or 25-hydroxyvitamin D concentration associated with 50% lower risk compared to <100IU/day Vitamin D or <13ng/ml serum 25-hydroxyvitamin D. Medians of these values were determined. RESULTS Overall, individuals with >or=1000IU/day oral Vitamin D (p<0.0001) or >or=33ng/ml (82nmol/l) serum 25-hydroxyvitamin D (p<0.01) had 50% lower incidence of colorectal cancer compared to reference values. CONCLUSIONS Intake of 1000IU/day of Vitamin D, half the safe upper intake established by the National Academy of Sciences, was associated with 50% lower risk. Serum 25-hydroxyvitamin D of 33ng/ml, which is known to be safe, also was associated with 50% lower risk. Prompt public health action is needed to increase intake of Vitamin D(3) to 1000IU/day, and to raise 25-hydroxyvitamin D by encouraging a modest duration of sunlight exposure.
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The Biological Significance of PACAP and PACAP Receptors in Human Tumors: From Cell Lines to Cancers. PITUITARY ADENYLATE CYCLASE-ACTIVATING POLYPEPTIDE 2003. [DOI: 10.1007/978-1-4615-0243-2_17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Abstract
Population-based studies have established that long-term intake of non-steroidal anti-inflammatory drugs (NSAIDs), compounds that inhibit the enzymatic activity of cyclooxygenase (COX), reduces the relative risk for developing colorectal cancer. These studies led to the identification of a molecular target, COX-2, that is involved in tumour promotion during colorectal cancer progression. Recent studies in humans indicate that therapy with specific COX-2 inhibitors might be an effective approach to colorectal cancer prevention and treatment.
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Affiliation(s)
- R A Gupta
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232-2279, USA
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Blake BW, Enslein K, Gombar VK, Borgstedt HH. Salmonella mutagenicity and rodent carcinogenicity: quantitative structure-activity relationships. Mutat Res 1990; 241:261-71. [PMID: 2195334 DOI: 10.1016/0165-1218(90)90023-u] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Based on a compilation of 222 reports of rodent nominal lifetime carcinogenicity bioassays by the NCI/NTP on the one hand, and corresponding Salmonella mutagenicity bioassays (Ames tests) on the other, Ashby and Tennant (1988) have divided the carcinogens and non-carcinogens into genotoxic (Ames test positive) and non-genotoxic (Ames test negative) groups and discussed structural characteristics common to each of these groups. The Ames test alone was deemed to be adequate for the identification of genotoxicity because other short-term bioassays, and even combinations, or batteries, appeared to offer no significant advantages. From the results of this study it is possible to achieve (1) a division of the carcinogens into the same genotoxic and non-genotoxic groups, and (2) a division of the non-genotoxic compounds into the same carcinogenic and non-carcinogenic groups, solely on the basis of structure-activity relationships, with a classification accuracy of approx. 95%. (1) An equation comprising 8 sigma molecular charge descriptors, 2 molecular connectivity indices (MCIs), 2 kappa molecular shape descriptors and one MOLSTAC substructure descriptor achieved discrimination between genotoxic and non-genotoxic carcinogens with an accuracy of 94.5%. (2) Another equation comprising 8 sigma molecular charge descriptors, 3 MCIs, one kappa shape descriptor and 12 substructural descriptors achieved discrimination between non-genotoxic carcinogens and non-genotoxic non-carcinogens with an accuracy of 95.2%. These SAR models are suitable for the distinction between (1) genotoxic and non-genotoxic carcinogens and (2) carcinogenic and non-carcinogenic non-genotoxins, both in the absence of animal bioassay data.
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Lijinsky W, Thomas BJ, Kovatch RM. Effects of feminization of male F344 rats on induction of tumors and on nucleic acid alkylation by nitrosobis-(2-oxopropyl)amine. Chem Biol Interact 1988; 66:111-9. [PMID: 3383283 DOI: 10.1016/0009-2797(88)90045-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Groups of male and female F344 rats were treated twice weekly by gavage with 2.5 mg of nitrosobis-(2-oxopropyl)amine (BOP) for 35 weeks. Additional groups given the same treatment were male rats castrated at birth, male rats bearing an implant of a pellet containing estradiol and castrated male rats bearing an estradiol pellet. Most rats died with tumors related to the treatment; intact male rats survived the least well of the five groups. Most rats in all groups had alveolar/bronchiolar neoplasms of the lung. Many of the male rats also had follicular cell neoplasms of the thyroid and transitional cell neoplasms of the urinary bladder and kidney pelvis; there were no liver tumors in intact male rats. Almost all female rats and castrated male rats had liver neoplasms, including hepatocellular, cholangiocellular and hemangiosarcomatous neoplasms, but few neoplasms of the thyroid, kidney or bladder. The male rats feminized with estradiol, intact or castrated, had liver neoplasms, mainly cholangiocellular, and also neoplasms of the thyroid. Two rats of each of the five groups were treated at 20 weeks of age with [14C]BOP. As measured by respiration of 14CO2, metabolism of BOP was faster in the two groups of male rats with the estradiol implant than in the other groups. DNA and RNA of the liver were isolated 6 h after treatment. The extent of methylation of liver DNA as 7-methylguanine and O6-methylguanine was higher in the females and in the feminized males than in the intact male rats, but when normalized to the dose of nitrosamine per unit body weight there was little difference among the five groups.
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Affiliation(s)
- W Lijinsky
- NCI-Frederick Cancer Research Facility, BRI-Basic Research Program, MD 21701
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