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Hattangady NG, Carter K, Maroni-Rana B, Wang T, Ayers JL, Yu M, Grady WM. Mapping the core senescence phenotype of primary human colon fibroblasts. Aging (Albany NY) 2024; 16:3068-3087. [PMID: 38385965 DOI: 10.18632/aging.205577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 01/15/2024] [Indexed: 02/23/2024]
Abstract
Advanced age is the largest risk factor for many diseases and several types of cancer, including colorectal cancer (CRC). Senescent cells are known to accumulate with age in various tissues, where they can modulate the surrounding tissue microenvironment through their senescence associated secretory phenotype (SASP). Recently, we showed that there is an increased number of senescent cells in the colons of CRC patients and demonstrated that senescent fibroblasts and their SASP create microniches in the colon that are conducive to CRC onset and progression. However, the composition of the SASP is heterogenous and cell-specific, and the precise senescence profile of colon fibroblasts has not been well-defined. To generate a SASP atlas of human colon fibroblasts, we induced senescence in primary human colon fibroblasts using various in vitro methods and assessed the resulting transcriptome. Using RNASequencing and further validation by quantitative RT-PCR and Luminex assays, we define and validate a 'core senescent profile' that might play a significant role in shaping the colon microenvironment. We also performed KEGG analysis and GO analyses to identify key pathways and biological processes that are differentially regulated in colon fibroblast senescence. These studies provide insights into potential driver proteins involved in senescence-associated diseases, like CRC, which may lead to therapies to improve overall health in the elderly and to prevent CRC.
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Affiliation(s)
- Namita Ganesh Hattangady
- Translational Science and Therapeutics Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Kelly Carter
- Translational Science and Therapeutics Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Brett Maroni-Rana
- Translational Science and Therapeutics Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Ting Wang
- Translational Science and Therapeutics Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Jessica Lee Ayers
- Translational Science and Therapeutics Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Ming Yu
- Translational Science and Therapeutics Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - William M Grady
- Translational Science and Therapeutics Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
- Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
- Division of Gastroenterology, University of Washington School of Medicine, Seattle, WA 98195, USA
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2
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Cheng J, Zhou J. Unraveling the gut health puzzle: exploring the mechanisms of butyrate and the potential of High-Amylose Maize Starch Butyrate (HAMSB) in alleviating colorectal disturbances. Front Nutr 2024; 11:1285169. [PMID: 38304546 PMCID: PMC10830644 DOI: 10.3389/fnut.2024.1285169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 01/02/2024] [Indexed: 02/03/2024] Open
Abstract
Colorectal disturbances encompass a variety of disorders that impact the colon and rectum, such as colitis and colon cancer. Butyrate, a short-chain fatty acid, plays a pivotal role in supporting gut health by nourishing colonocytes, promoting barrier function, modulating inflammation, and fostering a balanced microbiome. Increasing colorectal butyrate concentration may serve as a critical strategy to improve colon function and reduce the risk of colorectal disturbances. Butyrylated high-amylose maize starch (HAMSB) is an edible ingredient that efficiently delivers butyrate to the colon. HAMSB is developed by esterifying a high-amylose starch backbone with butyric anhydride. With a degree of substitution of 0.25, each hydroxy group of HAMSB is substituted by a butyryl group in every four D-glucopyranosyl units. In humans, the digestibility of HAMSB is 68% (w/w), and 60% butyrate molecules attached to the starch backbone is absorbed by the colon. One clinical trial yielded two publications, which showed that HAMSB significantly reduced rectal O6-methyl-guanine adducts and epithelial proliferation induced by the high protein diet. Fecal microbial profiles were assessed in three clinical trials, showing that HAMSB supplementation was consistently linked to increased abundance of Parabacteroides distasonis. In animal studies, HAMSB was effective in reducing the risk of diet- or AOM-induced colon cancer by reducing genetic damage, but the mechanisms differed. HAMSB functioned through affecting cecal ammonia levels by modulating colon pH in diet-induced cancer, while it ameliorated chemical-induced colon cancer through downregulating miR19b and miR92a expressions and subsequently activating the caspase-dependent apoptosis. Furthermore, animal studies showed that HAMSB improved colitis via regulating the gut immune modulation by inhibiting histone deacetylase and activating G protein-coupled receptors, but its role in bacteria-induced colon colitis requires further investigation. In conclusion, HAMSB is a food ingredient that may deliver butyrate to the colon to support colon health. Further clinical trials are warranted to validate earlier findings and determine the minimum effective dose of HAMSB.
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Affiliation(s)
- Junrui Cheng
- Global Scientific and Regulatory Department, Ingredion Incorporated, Bridgewater, NJ, United States
| | - Jing Zhou
- Global Scientific and Regulatory Department, Ingredion Incorporated, Bridgewater, NJ, United States
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Konorev D, Yao L, Turesky RJ. Multi-DNA Adduct and Abasic Site Quantitation In Vivo by Nano-Liquid Chromatography/High-Resolution Orbitrap Tandem Mass Spectrometry: Methodology for Biomonitoring Colorectal DNA Damage. Chem Res Toxicol 2022; 35:1519-1532. [PMID: 36066083 PMCID: PMC9665354 DOI: 10.1021/acs.chemrestox.2c00177] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Epidemiological and mechanistic studies suggest that processed and red meat consumption and tobacco smoking are associated with colorectal cancer (CRC) risk. Several classes of carcinogens, including N-nitroso compounds (NOCs) in processed meats and heterocyclic aromatic amines (HAAs) and polycyclic aromatic hydrocarbons (PAHs) in grilled meats and tobacco smoke, undergo metabolism to reactive intermediates that may form mutation-inducing DNA adducts in the colorectum. Heme iron in red meat may contribute to oxidative DNA damage and endogenous NOC formation. However, the chemicals involved in colorectal DNA damage and the paradigms of CRC etiology remain unproven. There is a critical need to establish physicochemical methods for identifying and quantitating DNA damage induced by genotoxicants in the human colorectum. We established robust nano-liquid chromatography/high-resolution accurate mass Orbitrap tandem mass spectrometry (LC/HRAMS2) methods to measure DNA adducts of nine meat and tobacco-associated carcinogens and lipid peroxidation products in the liver, colon, and rectum of carcinogen-treated rats employing fresh-frozen and formalin-fixed paraffin-embedded (FFPE) tissues. Some NOCs form O6-carboxymethyl-2'-deoxyguanosine, O6-methyl-2'-deoxyguanosine, and unstable quaternary N-linked purine/pyrimidine adducts, which generate apurinic/apyrimidinic (AP) sites. AP sites were quantitated following derivatization with O-(pyridin-3-yl-methyl)hydroxylamine. DNA adduct quantitation was conducted with stable isotope-labeled internal standards, and method performance was validated for accuracy and reproducibility. Limits of quantitation ranged from 0.1 to 1.1 adducts per 108 bases using 3 μg of DNA. Adduct formation in animals ranged from ∼1 in 108 to ∼1 in 105 bases, occurring at comparable levels in fresh-frozen and FFPE specimens for most adducts. AP sites increased by 25- to 75-fold in the colorectum and liver, respectively. Endogenous lipid peroxide-derived 3-(2-deoxy-β-d-erythro-pentofuranosyl)pyrimido[1,2-α]purin-10(3H)-one (M1dG) and 6-oxo-M1dG adduct levels were not increased by carcinogen dosing but increased in FFPE tissues. Human biomonitoring studies can implement LC/HRAMS2 assays for DNA adducts and AP sites outlined in this work to advance our understanding of CRC etiology.
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Affiliation(s)
- Dmitri Konorev
- Masonic Cancer Center, University of Minnesota,
Minneapolis, MN 55455
- Department of Medicinal Chemistry, University of Minnesota,
Minneapolis, MN 55455
| | - Lihua Yao
- Masonic Cancer Center, University of Minnesota,
Minneapolis, MN 55455
- Department of Medicinal Chemistry, University of Minnesota,
Minneapolis, MN 55455
| | - Robert. J. Turesky
- Masonic Cancer Center, University of Minnesota,
Minneapolis, MN 55455
- Department of Medicinal Chemistry, University of Minnesota,
Minneapolis, MN 55455
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Adherence to the Western, Prudent and Mediterranean Dietary Patterns and Colorectal Cancer Risk: Findings from the Spanish Cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Spain). Nutrients 2022; 14:nu14153085. [PMID: 35956262 PMCID: PMC9370446 DOI: 10.3390/nu14153085] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/18/2022] [Accepted: 07/21/2022] [Indexed: 12/13/2022] Open
Abstract
The aim of this study was to explore the association between three previously identified dietary patterns (Western, Prudent, and Mediterranean) and colorectal cancer (CRC) risk by sex and cancer subtype. The Spanish cohort of the European Prospective Investigation into Cancer and Nutrition study provided dietary and epidemiological information from 15,629 men and 25,808 women recruited between 1992 and 1996. Among them, 568 CRC cases and 3289 deaths were identified during a median follow-up of 16.98 years. The associations between adherence to the three dietary patterns and CRC risk (overall, by sex, and by tumour location: proximal and distal colon and rectum) were investigated by fitting multivariate Cox proportional hazards regression models stratified by study centre and age. Possible heterogeneity of the effects by sex and follow-up time (1–10 vs. ≥10 years) was also explored. While no clear effect of the Prudent dietary pattern on CRC risk was found, a suggestive detrimental effect of the Western dietary pattern was observed, especially during the first 10 years of follow-up (HR1SD-increase (95% CI): 1.17 (0.99–1.37)), among females (HR1SD-increase (95% CI): 1.31 (1.06–1.61)), and for rectal cancer (HR1SD-increase (95% CI): 1.38 (1.03–1.84)). In addition, high adherence to the Mediterranean pattern seemed to protect against CRC, especially when restricting the analyses to the first 10 years of follow-up (HR1SD-increase (95% CI): 0.84 (0.73–0.98)), among males (HR1SD-increase (95% CI): 0.80 (0.65–0.98)), and specifically against distal colon cancer (HR1SD-increase (95% CI): 0.81 (0.63–1.03)). In conclusion, low adherence to the Western diet and high adherence to the Mediterranean dietary pattern could prevent CRC, especially distal colon and rectal cancer.
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Zhang J, Wang Y, Wang Y, Zhang P, Chen HY, Huang S. Discrimination between Different DNA Lesions by Monitoring Single-Molecule Polymerase Stalling Kinetics during Nanopore Sequencing. NANO LETTERS 2022; 22:5561-5569. [PMID: 35713465 DOI: 10.1021/acs.nanolett.2c01833] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
O6-Carboxymethylguanosine (O6-CMG), O6-methylguanosine (O6-MeG), and abasic site (AP site) are DNA lesions induced by alkylating agents. Identification of these lesions in DNA may aid in understanding their relevance to carcinogenesis and may be used for diagnosis. Nanopore sequencing (NPS) may directly report nucleotide modifications solely from the nanopore readout. However, the conventional NPS strategy still suffers from interferences from neighboring sequences. Instead, by observation of the enzymatic stalling kinetics caused by the O6-CMG, O6-MeG, or AP site, discrimination between different DNA lesions is directly achieved. This strategy is not interfered with by the sequence context around the lesion. The lesion, which retards the movement of the DNA through the pore, efficiently prohibits misreading of the DNA lesion. These results suggest a new strategy in the identification of DNA lesions or DNA modifications. It also provides a high-resolution biophysical tool to investigate enzymatic kinetics caused by DNA lesions and the corresponding enzymes.
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Affiliation(s)
- Jinyue Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023 Nanjing, China
| | - Yu Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023 Nanjing, China
| | - Yuqin Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023 Nanjing, China
| | - Panke Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
| | - Hong-Yuan Chen
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
| | - Shuo Huang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 210023 Nanjing, China
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Li Y, Hecht SS. Metabolic Activation and DNA Interactions of Carcinogenic N-Nitrosamines to Which Humans Are Commonly Exposed. Int J Mol Sci 2022; 23:ijms23094559. [PMID: 35562949 PMCID: PMC9105260 DOI: 10.3390/ijms23094559] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 02/04/2023] Open
Abstract
Carcinogenic N-nitrosamine contamination in certain drugs has recently caused great concern and the attention of regulatory agencies. These carcinogens-widely detectable in relatively low levels in food, water, cosmetics, and drugs-are well-established and powerful animal carcinogens. The electrophiles resulting from the cytochrome P450-mediated metabolism of N-nitrosamines can readily react with DNA and form covalent addition products (DNA adducts) that play a central role in carcinogenesis if not repaired. In this review, we aim to provide a comprehensive and updated review of progress on the metabolic activation and DNA interactions of 10 carcinogenic N-nitrosamines to which humans are commonly exposed. Certain DNA adducts such as O6-methylguanine with established miscoding properties play central roles in the cancer induction process, whereas others have been linked to the high incidence of certain types of cancers. We hope the data summarized here will help researchers gain a better understanding of the bioactivation and DNA interactions of these 10 carcinogenic N-nitrosamines and facilitate further research on their toxicologic and carcinogenic properties.
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Affiliation(s)
- Yupeng Li
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA;
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, USA
- Correspondence: ; Tel.: +1-612-624-8187
| | - Stephen S. Hecht
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA;
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Lu K, Hsiao YC, Liu CW, Schoeny R, Gentry R, Starr TB. A Review of Stable Isotope Labeling and Mass Spectrometry Methods to Distinguish Exogenous from Endogenous DNA Adducts and Improve Dose-Response Assessments. Chem Res Toxicol 2021; 35:7-29. [PMID: 34910474 DOI: 10.1021/acs.chemrestox.1c00212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cancer remains the second most frequent cause of death in human populations worldwide, which has been reflected in the emphasis placed on management of risk from environmental chemicals considered to be potential human carcinogens. The formation of DNA adducts has been considered as one of the key events of cancer, and persistence and/or failure of repair of these adducts may lead to mutation, thus initiating cancer. Some chemical carcinogens can produce DNA adducts, and DNA adducts have been used as biomarkers of exposure. However, DNA adducts of various types are also produced endogenously in the course of normal metabolism. Since both endogenous physiological processes and exogenous exposure to xenobiotics can cause DNA adducts, the differentiation of the sources of DNA adducts can be highly informative for cancer risk assessment. This review summarizes a highly applicable methodology, termed stable isotope labeling and mass spectrometry (SILMS), that is superior to previous methods, as it not only provides absolute quantitation of DNA adducts but also differentiates the exogenous and endogenous origins of DNA adducts. SILMS uses stable isotope-labeled substances for exposure, followed by DNA adduct measurement with highly sensitive mass spectrometry. Herein, the utilities and advantage of SILMS have been demonstrated by the rich data sets generated over the last two decades in improving the risk assessment of chemicals with DNA adducts being induced by both endogenous and exogenous sources, such as formaldehyde, vinyl acetate, vinyl chloride, and ethylene oxide.
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Affiliation(s)
- Kun Lu
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Yun-Chung Hsiao
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Chih-Wei Liu
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Rita Schoeny
- Rita Schoeny LLC, 726 Fifth Street NE, Washington, D.C. 20002, United States
| | - Robinan Gentry
- Ramboll US Consulting, Inc., Monroe, Louisiana 71201, United States
| | - Thomas B Starr
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,TBS Associates, 7500 Rainwater Road, Raleigh, North Carolina 27615, United States
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Geisen SM, Aloisi CMN, Huber SM, Sandell ES, Escher NA, Sturla SJ. Direct Alkylation of Deoxyguanosine by Azaserine Leads to O6-Carboxymethyldeoxyguanosine. Chem Res Toxicol 2021; 34:1518-1529. [PMID: 34061515 DOI: 10.1021/acs.chemrestox.0c00471] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The O6-alkylguanosine adduct O6-carboxymethyldeoxyguanosine (O6-CMdG) has been detected at elevated levels in blood and tissue samples from colorectal cancer patients and from healthy volunteers after consuming red meat. The diazo compound l-azaserine leads to the formation of O6-CMdG as well as the corresponding methyl adduct O6-methyldeoxyguanosine (O6-MedG) in cells and is therefore in wide use as a chemical probe in cellular studies concerning DNA damage and mutation. However, there remain knowledge gaps concerning the chemical basis of DNA adduct formation by l-azaserine. To characterize O6-CMdG formation by l-azaserine, we carried out a combination of chemical and enzymatic stability and reactivity studies supported by liquid chromatography tandem mass spectrometry for the simultaneous quantification of O6-CMdG and O6-MedG. We found that l-azaserine is stable under physiological and alkaline conditions as well as in active biological matrices but undergoes acid-catalyzed hydrolysis. We show, for the first time, that l-azaserine reacts directly with guanosine (dG) and oligonucleotides to form an O6-serine-CMdG (O6-Ser-CMdG) adduct. Moreover, by characterizing the reaction of dG with l-azaserine, we demonstrate that O6-Ser-CMdG forms as an intermediate that spontaneously decomposes to form O6-CMdG. Finally, we quantified levels of O6-CMdG and O6-MedG in a human cell line exposed to l-azaserine and found maximal adduct levels after 48 h. The findings of this work elucidate the chemical basis of how l-azaserine reacts with deoxyguanosine and support its use as a chemical probe for N-nitroso compound exposure in carcinogenesis research, particularly concerning the identification of pathways and factors that promote adduct formation.
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Affiliation(s)
- Susanne M Geisen
- Department of Health Science and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Claudia M N Aloisi
- Department of Health Science and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Sabrina M Huber
- Department of Health Science and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Emma S Sandell
- Department of Health Science and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Nora A Escher
- Department of Health Science and Technology, ETH Zurich, 8092 Zurich, Switzerland
| | - Shana J Sturla
- Department of Health Science and Technology, ETH Zurich, 8092 Zurich, Switzerland
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Sex Differences in Colon Cancer Metabolism Reveal A Novel Subphenotype. Sci Rep 2020; 10:4905. [PMID: 32184446 PMCID: PMC7078199 DOI: 10.1038/s41598-020-61851-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 03/04/2020] [Indexed: 11/09/2022] Open
Abstract
Women have a lower incidence of colorectal cancer (CRC) than men, however, they have a higher incidence of right-sided colon cancer (RCC). This is of concern as patients with RCC have the poorest clinical outcomes among all CRC patients. Aberrant metabolism is a known hallmark and therapeutic target for cancer. We propose that metabolic subphenotypes exist between CRCs due to intertumoral molecular and genomic variation, and differences in environmental milieu of the colon which vary between the sexes. Metabolomics analysis of patient colon tumors (n = 197) and normal tissues (n = 39) revealed sex-specific metabolic subphenotypes dependent on anatomic location. Tumors from women with RCC were nutrient-deplete, showing enhanced energy production to fuel asparagine synthesis and amino acid uptake. The clinical importance of our findings were further investigated in an independent data set from The Cancer Genomic Atlas, and demonstrated that high asparagine synthetase (ASNS) expression correlated with poorer survival for women. This is the first study to show a unique, nutrient-deplete metabolic subphenotype in women with RCC, with implications for tumor progression and outcomes in CRC patients.
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Xi Y, Yuefen P, Wei W, Quan Q, Jing Z, Jiamin X, Shuwen H. Analysis of prognosis, genome, microbiome, and microbial metabolome in different sites of colorectal cancer. J Transl Med 2019; 17:353. [PMID: 31665031 PMCID: PMC6819376 DOI: 10.1186/s12967-019-2102-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 10/18/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The colorectum includes ascending colon, transverse colon, descending colon, sigmoid colon, and rectum. Different sites of colorectal cancer (CRC) are different in many aspects, including clinical symptoms, biological behaviour, and prognosis. PURPOSE This study aimed to analyse prognosis, genes, bacteria, fungi, and microbial metabolome in different sites of CRC. METHODS The Surveillance, Epidemiology, and End Results (SEER) database and STAT were used to statistically describe and analyse the prognosis in different sites of CRC. RNA sequences of CRC from Broad Institute's GDAC Firehose were re-annotated and reanalysed based on different sites using weighted gene co-expression network analysis (WGCNA). The Kaplan-Meier method was used to analyse the prognosis and Cytoscape was used to construct a drug-target network based on DGIdb databases. Bacterial 16S V3-V4 and fungal ITS V3-V4 ribosomal RNA genes of stool samples were sequenced. Gas chromatography/mass spectrometry (GS/MS) was performed to detect the microbial metabolites in stool samples. Bioinformatics analysis was performed to compare distinct gut microorganisms and microbial metabolites between rectal and sigmoid cancers. RESULTS The prognosis in CRC with different sites is significantly different. The closer to the anus predicted longer survival time. The difference between genes and co-expression pairs in CRC with different sites were constructed. The relative abundance of 112 mRNAs and 26 lncRNAs correlated with the sites of CRC were listed. Nine differentially expressed genes at different sites of CRC were correlated with prognosis. A drug-gene interaction network contained 227 drug-gene pairs were built. The relative abundance of gut bacteria and gut fungus, and the content of microbe-related metabolites were statistically different between rectal and sigmoid cancers. CONCLUSIONS There are many differences in prognosis, genome, drug targets, gut microbiome, and microbial metabolome in different colorectal cancer sites. These findings may improve our understanding of the role of the CRC sites in personalized and precision medicine.
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Affiliation(s)
- Yang Xi
- Department of Oncology, Huzhou Central Hospital, Affiliated Central Hospital HuZhou University, 198 Hongqi Rd, Huzhou, 313000, Zhejiang, People's Republic of China
| | - Pan Yuefen
- Department of Oncology, Huzhou Central Hospital, Affiliated Central Hospital HuZhou University, 198 Hongqi Rd, Huzhou, 313000, Zhejiang, People's Republic of China
| | - Wu Wei
- Department of Gastroenterology, Huzhou Central Hospital, Affiliated Central Hospital HuZhou University, 198 Hongqi Rd, Huzhou, 313000, Zhejiang, People's Republic of China
| | - Qi Quan
- Department of Oncology, Huzhou Central Hospital, Affiliated Central Hospital HuZhou University, 198 Hongqi Rd, Huzhou, 313000, Zhejiang, People's Republic of China
| | - Zhuang Jing
- Graduate School of Nursing, Huzhou University, No. 1 Bachelor Road, Huzhou, 313000, Zhejiang, People's Republic of China
| | - Xu Jiamin
- Graduate School of Nursing, Huzhou University, No. 1 Bachelor Road, Huzhou, 313000, Zhejiang, People's Republic of China
| | - Han Shuwen
- Department of Oncology, Huzhou Central Hospital, Affiliated Central Hospital HuZhou University, 198 Hongqi Rd, Huzhou, 313000, Zhejiang, People's Republic of China.
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11
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Islam Z, Akter S, Kashino I, Mizoue T, Sawada N, Mori N, Yamagiwa Y, Tsugane S, Naito M, Tamakoshi A, Wada K, Nagata C, Sugawara Y, Tsuji I, Matsuo K, Ito H, Lin Y, Kitamura Y, Sadakane A, Tanaka K, Shimazu T, Inoue M. Meat subtypes and colorectal cancer risk: A pooled analysis of 6 cohort studies in Japan. Cancer Sci 2019; 110:3603-3614. [PMID: 31482651 PMCID: PMC6825004 DOI: 10.1111/cas.14188] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 08/04/2019] [Accepted: 08/29/2019] [Indexed: 12/23/2022] Open
Abstract
Red meat and processed meat have been suggested to increase risk of colorectal cancer (CRC), especially colon cancer. However, it remains unclear whether these associations differ according to meat subtypes or colon subsites. The present study addressed this issue by undertaking a pooled analysis of large population-based cohort studies in Japan: 5 studies comprising 232 403 participants (5694 CRC cases) for analysis based on frequency of meat intake, and 2 studies comprising 123 635 participants (3550 CRC cases) for analysis based on intake quantity. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using the Cox proportional hazards model and then pooled using the random effect model. Comparing the highest vs lowest quartile, beef intake was associated with an increased risk of colon cancer in women (pooled HR 1.20; 95% CI, 1.01-1.44) and distal colon cancer (DCC) risk in men (pooled HR 1.30; 95% CI, 1.05-1.61). Frequent intake of pork was associated with an increased risk of distal colon cancer in women (pooled HR 1.44; 95% CI, 1.10-1.87) for "3 times/wk or more" vs "less than 1 time/wk". Frequent intake of processed red meat was associated with an increased risk of colon cancer in women (pooled HR 1.39; 95% CI, 0.97-2.00; P trend = .04) for "almost every day" vs "less than 1 time/wk". No association was observed for chicken consumption. The present findings support that intake of beef, pork (women only), and processed red meat (women only) might be associated with a higher risk of colon (distal colon) cancer in Japanese.
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Affiliation(s)
- Zobida Islam
- Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan
| | - Shamima Akter
- Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan
| | - Ikuko Kashino
- Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan
| | - Tetsuya Mizoue
- Department of Epidemiology and Prevention, Center for Clinical Sciences, National Center for Global Health and Medicine, Tokyo, Japan
| | - Norie Sawada
- Epidemiology and Prevention Group, Research Center for Public Health Sciences, National Cancer Center, Tokyo, Japan
| | - Nagisa Mori
- Epidemiology and Prevention Group, Research Center for Public Health Sciences, National Cancer Center, Tokyo, Japan
| | - Yoko Yamagiwa
- Epidemiology and Prevention Group, Research Center for Public Health Sciences, National Cancer Center, Tokyo, Japan
| | - Shoichiro Tsugane
- Epidemiology and Prevention Group, Research Center for Public Health Sciences, National Cancer Center, Tokyo, Japan
| | - Mariko Naito
- Department of Oral Epidemiology, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan
| | - Akiko Tamakoshi
- Department of Public Health, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Keiko Wada
- Department of Epidemiology and Preventive Medicine, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Chisato Nagata
- Department of Epidemiology and Preventive Medicine, Gifu University Graduate School of Medicine, Gifu, Japan
| | - Yumi Sugawara
- Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Ichiro Tsuji
- Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Keitaro Matsuo
- Division of Cancer Epidemiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.,Division of Cancer Epidemiology and Prevention, Aichi Cancer Center Research Institute, Nagoya, Japan
| | - Hidemi Ito
- Division of Cancer Information and Control, Department of Preventive Medicine, Aichi Cancer Center Research Institute, Nagoya, Japan.,Division of Cancer Descriptive Epidemiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yingsong Lin
- Department of Public Health, Aichi Medical University School of Medicine, Aichi, Japan
| | - Yuri Kitamura
- Department of Social Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Atsuko Sadakane
- Department of Epidemiology, Radiation Effects Research Foundation, Hiroshima, Japan
| | - Keitaro Tanaka
- Department of Preventive Medicine, Faculty of Medicine, Saga University, Saga, Japan
| | - Taichi Shimazu
- Epidemiology and Prevention Group, Research Center for Public Health Sciences, National Cancer Center, Tokyo, Japan
| | - Manami Inoue
- Epidemiology and Prevention Group, Research Center for Public Health Sciences, National Cancer Center, Tokyo, Japan
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12
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Räz MH, Sandell ES, Patil KM, Gillingham DG, Sturla SJ. High Sensitivity of Human Translesion DNA Synthesis Polymerase κ to Variation in O 6-Carboxymethylguanine Structures. ACS Chem Biol 2019; 14:214-222. [PMID: 30645109 DOI: 10.1021/acschembio.8b00802] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Carboxymethylation of DNA, including the formation of the DNA adduct O6-carboxymethylguanine ( O6-CMG), is associated with lifestyle factors, such as diet. It can impede replicative polymerases (Pols) and lead to replication fork stalling, or an alternative means for replication to proceed by translesion DNA synthesis (TLS). TLS requires specialized DNA Pols characterized by open and preformed active sites capable of preferential bypass of alkylated DNA adducts but that have high error rates, leading to mutations. Human TLS Pols can bypass O6-CMG with varying degrees of accuracy, but it is not known how the chemical structure of the O6-CMG adduct influences polymerase proficiency or fidelity. To better understand how adduct structure determines dNTP selection at lesion sites, we prepared DNA templates with a series of O6-CMG structural analogs and compared the primer extension patterns of Y- and X-family Pols in response to these modifications. The results indicate that the structure of the DNA adduct had a striking effect on dNTP selection by Pol κ and that an increased steric size influences the fidelity of Pol η, whereas Pol ι and β function were only marginally affected. To test the hypothesis that specific hydrogen bonding interactions between the templating base and the incoming dNTP are a basis of this selection, we modeled the structural analogs with incoming dNTP in the Pol κ active site. These data indicate that the base pairing geometry and stabilization by a dense hydrogen bonding network are important molecular features for dNTP incorporation, providing a basis for understanding error-free bypass of O6-CMG by Pol κ.
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Affiliation(s)
- Michael H. Räz
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092, Zürich, Switzerland
| | - Emma S. Sandell
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092, Zürich, Switzerland
| | - Kiran M. Patil
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Dennis G. Gillingham
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Shana J. Sturla
- Department of Health Sciences and Technology, ETH Zürich, Schmelzbergstrasse 9, 8092, Zürich, Switzerland
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13
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Turesky RJ. Mechanistic Evidence for Red Meat and Processed Meat Intake and Cancer Risk: A Follow-up on the International Agency for Research on Cancer Evaluation of 2015. Chimia (Aarau) 2018; 72:718-724. [PMID: 30376922 PMCID: PMC6294997 DOI: 10.2533/chimia.2018.718] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The Working Group of the International Agency for Research on Cancer classified the consumption of processed meat as carcinogenic to humans (Group 1), and classified red meat as probably carcinogenic to humans (Group 2A); consumption of both meat types is associated with an increased risk of colorectal cancer. These classifications are based on a compilation of epidemiology data and mechanistic evidence from animal and human studies. The curing of meats with nitrite can produce carcinogenic N-nitroso compounds (NOCs), and the smoking of meat produces polycyclic aromatic hydrocarbons (PAHs). The high-temperature cooking of meat also produces carcinogenic heterocyclic aromatic amines (HAAs). The ingestion of heme from meat can catalyze the formation of NOCs and lipid peroxidation products (LPOs) in the digestive tract. Many of these chemicals form DNA adducts, some of which can induce mutations and initiate carcinogenesis. Another recent hypothesis is that N-glycolylneuraminic acid, a non-human sialic acid sugar present in red meat, becomes incorporated in the cell membrane, triggering the immune response with associated inflammation and reactive oxygen species, which can contribute to DNA damage, tumor promotion, and cancer. The mechanisms by which these chemicals in meat induce DNA damage, and the impact of dietary and host factors that influence the biological potency of these chemicals are highlighted in this updated report.
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Affiliation(s)
- Robert J Turesky
- Masonic Cancer Center Department of Medicinal Chemistry College of Pharmacy, University of Minnestoa 2231 6th St SE, Minneapolis, MN, USA;,
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14
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Etemadi A, Abnet CC, Graubard BI, Beane-Freeman L, Freedman ND, Liao L, Dawsey SM, Sinha R. Anatomical subsite can modify the association between meat and meat compounds and risk of colorectal adenocarcinoma: Findings from three large US cohorts. Int J Cancer 2018; 143:2261-2270. [PMID: 29873077 DOI: 10.1002/ijc.31612] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 04/12/2018] [Accepted: 05/09/2018] [Indexed: 12/24/2022]
Abstract
Distal and proximal colon tumors have distinct incidence trends and embryonic origins; whether these sub-sites have distinct susceptibilities to known risk factors is unclear. We used pooled data from 407,270 participants in three US-based studies, with overall median follow-up of 13.8 years. We used adjusted Cox models to analyze the association between dietary intakes (from diet history questionnaire) of total, processed and unprocessed red meat; total white meat, poultry and fish and meat-related compounds: heme iron, nitrate, nitrite, the heterocyclic amines (HCAs) and benzo(a)pyrene (B(a)P) and incidence of colorectal cancer subsites. The risk of colorectal cancer (n = 6,640) increased by 35% for each 50 g/1,000 kcal higher daily intake of total red meat, with a significant right-to-left trend from proximal colon (HR: 1.24; 95% CI: 1.09-1.39) to distal colon (HR: 1.34; 95% CI: 1.13-1.55) and rectum (HR: 1.53; 95% CI: 1.28-1.79). Only unprocessed red meat showed a significant right-to-left trend. Each 50 g/1,000 kcal increase in white meat intake was associated with a 26% reduction in total colorectal cancer risk (HR: 0.74; 95% CI: 0.68-0.80), with a significant inverse right-to-left trend. The highest quintile of heme iron was associated with increased cancer risk only in the distal colon (HR: 1.20; 95% CI: 1.02-1.42) and rectum (HR: 1.27; 95% CI: 1.07-1.52). The highest quintile of HCAs, and nitrate/nitrite were associated with increased risk of total colorectal cancer, but these associations did not vary across anatomical subsites. In summary, right and left subsites of the colon may have distinct susceptibilities to meat and possibly other dietary risk factors, suggesting that the causes of colorectal cancer may vary across anatomical subsites.
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Affiliation(s)
- Arash Etemadi
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
| | - Christian C Abnet
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
| | - Barry I Graubard
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
| | - Laura Beane-Freeman
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
| | - Neal D Freedman
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
| | - Linda Liao
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
| | - Sanford M Dawsey
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
| | - Rashmi Sinha
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
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15
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Zhou CB, Fang JY. The regulation of host cellular and gut microbial metabolism in the development and prevention of colorectal cancer. Crit Rev Microbiol 2018; 44:436-454. [PMID: 29359994 DOI: 10.1080/1040841x.2018.1425671] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Metabolism regulation is crucial in colorectal cancer (CRC) and has emerged as a remarkable field currently. The cellular metabolism of glucose, amino acids and lipids in CRC are all reprogrammed. Each of them changes tumour microenvironment, modulates bacterial composition and activity, and eventually promotes CRC development. Metabolites such as short chain fatty acids, secondary bile acids, N-nitroso compounds, hydrogen sulphide, polyphenols and toxins like fragilysin, FadA, cytolethal distending toxin and colibactin play a dual role in CRC. The relationship of gut microbe-metabolite is essential in remodelling intestinal microbial ecology composition and metabolic activity. It regulates the metabolism of colonic epithelial cells and changes the tumour microenvironment in CRC. Microbial metabolism manipulation has been considered to be potentially preventive in CRC, but more large-scale clinical trials are required before their application in clinical practice in the near future.
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Affiliation(s)
- Cheng-Bei Zhou
- a Division of Gastroenterology and Hepatology , Shanghai Jiao-Tong University School of Medicine Renji Hospital, Key Laboratory of Gastroenterology & Hepatology, Ministry of Health, State Key Laboratory of Oncogene and Related Gene. Shanghai Institute of Digestive Disease , Shanghai , China
| | - Jing-Yuan Fang
- a Division of Gastroenterology and Hepatology , Shanghai Jiao-Tong University School of Medicine Renji Hospital, Key Laboratory of Gastroenterology & Hepatology, Ministry of Health, State Key Laboratory of Oncogene and Related Gene. Shanghai Institute of Digestive Disease , Shanghai , China
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16
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Chiavarini M, Bertarelli G, Minelli L, Fabiani R. Dietary Intake of Meat Cooking-Related Mutagens (HCAs) and Risk of Colorectal Adenoma and Cancer: A Systematic Review and Meta-Analysis. Nutrients 2017; 9:nu9050514. [PMID: 28524104 PMCID: PMC5452244 DOI: 10.3390/nu9050514] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/08/2017] [Accepted: 05/15/2017] [Indexed: 12/12/2022] Open
Abstract
Much evidence suggests that the positive association between meat intake and colorectal adenoma (CRA) and cancer (CRC) risk is mediated by mutagenic compounds generated during cooking at high temperature. A number of epidemiological studies have estimated the effect of meat-related mutagens intake on CRC/CRA risk with contradictory and sometimes inconsistent results. A literature search was carried out (PubMed, Web of Science and Scopus) to identify articles reporting the relationship between the intake of meat-related mutagens (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f] quinoxaline: DiMeIQx, benzo(a) pyrene (B(a)P) and "meat derived mutagenic activity" (MDM)) and CRC/CRA risk. A random-effect model was used to calculate the risk association. Thirty-nine studies were included in the systematic review and meta-analysis. Polled CRA risk (15229 cases) was significantly increased by intake of PhIP (OR = 1.20; 95% CI: 1.13,1.28; p < 0.001), MeIQx (OR = 1.14; 95% CI: 1.05,1.23; p = 0.001), DiMeIQx (OR = 1.13; 95% CI: 1.05,1.21; p = 0.001), B(a)P (OR = 1.10; 95% CI: 1.02,1.19; p = 0.017) and MDM (OR = 1.17; 95% CI: 1.07,1.28; p = 0.001). A linear and curvilinear trend was observed in dose-response meta-analysis between CRA risk in association with PhIP, MDM, and MeIQx. CRC risk (21,344 cases) was increased by uptake of MeIQx (OR = 1.14; 95% CI: 1.04,1.25; p = 0.004), DiMeIQx (OR = 1.12; 95% CI: 1.02,1.22; p = 0.014) and MDM (OR = 1.12; 95% CI: 1.06,1.19; p < 0.001). No publication bias could be detected, whereas heterogeneity was in some cases rather high. Mutagenic compounds formed during cooking of meat at high temperature may be responsible of its carcinogenicity.
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Affiliation(s)
- Manuela Chiavarini
- Department of Experimental Medicine, University of Perugia, 06123 Perugia, Italy.
| | - Gaia Bertarelli
- Department of Economics, University of Perugia, 06123 Perugia, Italy.
| | - Liliana Minelli
- Department of Experimental Medicine, University of Perugia, 06123 Perugia, Italy.
| | - Roberto Fabiani
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123 Perugia, Italy.
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17
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A critical overview on the biological and molecular features of red and processed meat in colorectal carcinogenesis. J Gastroenterol 2017; 52:407-418. [PMID: 27913919 DOI: 10.1007/s00535-016-1294-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 11/21/2016] [Indexed: 02/04/2023]
Abstract
A recent investigation by the World Health Organisation (WHO) has found that the consumption of processed meat and potentially red meat promotes carcinogenesis and can increase the risk of colorectal cancer. This literature review aims to summarise both the red and processed meat molecules associated with colorectal carcinogenesis and investigate their relationship with the pathogenic process of colorectal cancer. Literature relating to the carcinogenic effect of red and processed meat molecules was critically reviewed. There are multiple molecules present in red and processed meat with a potential carcinogenic effect on colorectal tissues. Processed meat is more carcinogenic compared to red meat because of the abundance of potent nitrosyl-heme molecules that form N-nitroso compounds. Studies have also noted that other molecules such as polycyclic aromatic hydrocarbons and heterocyclic amines have potential mechanisms for the initiation of colorectal cancer pathogenesis. The non-human sugar molecule N-glycolylneuraminic acid may account for the carcinogenic effects of pork despite its heme content being comparable to that of chicken. Red meat products, especially those that have been processed, have a wide variety of carcinogenic molecules known to increase the risk of colorectal cancer. Thus, the outcome of this review is consistent with the recent findings of WHO.
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18
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Potjewyd G, Day PJ, Shangula S, Margison GP, Povey AC. L-β-N-methylamino-l-alanine (BMAA) nitrosation generates a cytotoxic DNA damaging alkylating agent: An unexplored mechanism for neurodegenerative disease. Neurotoxicology 2017; 59:105-109. [PMID: 28163087 DOI: 10.1016/j.neuro.2017.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 01/26/2017] [Accepted: 01/26/2017] [Indexed: 10/20/2022]
Abstract
BACKGROUND L-β-N-methylamino-l-alanine (BMAA) is a non-proteinic amino acid, that is neurotoxic in vitro and in animals, and is implicated in the causation of amyotrophic lateral sclerosis and parkinsonism-dementia complex (ALS-PDC) on Guam. Given that natural amino acids can be N-nitrosated to form toxic alkylating agents and the structural similarity of BMAA to other amino acids, our hypothesis was that N-nitrosation of BMAA might result in a toxic alkylating agent, providing a novel mechanistic hypothesis for BMAA action. FINDINGS We have chemically nitrosated BMAA with sodium nitrite to produce nitrosated BMAA (N-BMAA) which was shown to react with the alkyl-trapping agent, 4-(p-nitrobenzyl)pyridine, cause DNA strand breaks in vitro and was toxic to the human neuroblastoma cell line SH-SY5Y under conditions in which BMAA itself was minimally toxic. CONCLUSIONS Our results indicate that N-BMAA is an alkylating agent and toxin suggesting a plausible and previously unrecognised mechanism for the neurotoxic effects of BMAA.
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Affiliation(s)
- G Potjewyd
- Centre for Epidemiology, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - P J Day
- Centre for Epidemiology, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK; Manchester Institute for Biotechnology, University of Manchester, Manchester, UK
| | - S Shangula
- Centre for Epidemiology, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - G P Margison
- Centre for Epidemiology, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - A C Povey
- Centre for Epidemiology, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
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19
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Li D, Fu Q, Li M, Li J, Yin C, Zhao J, Li F. Primary tumor site and anti-EGFR monoclonal antibody benefit in metastatic colorectal cancer: a meta-analysis. Future Oncol 2017; 13:1115-1127. [PMID: 28110551 DOI: 10.2217/fon-2016-0468] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
AIM This meta-analysis aimed to document the impact of primary tumor site on anti-EGFR monoclonal antibody (mAb) benefit in metastatic colorectal cancer. MATERIALS & METHODS Tumors with metastatic left-sided colorectal cancer (LCC) were compared with tumors with metastatic right-sided colon cancer (RCC) with respect to anti-EGFR mAb objective response rate (ORR), overall survival (OS) and progression-free survival (PFS) benefit. RESULTS Comparing LCC with RCC, LCC was found to have significantly superior anti-EGFR mAb ORR (p < 0.00001), OS (p < 0.00001) and PFS (p < 0.00001) benefit. Additionally, anti-EGFR mAb therapy significantly improved both OS and PFS for LCC compared with no anti-EGFR mAb therapy, but not for RCC. The test of interaction was also apparent for OS (p = 0.0002) and PFS (p = 0.0002). CONCLUSION This meta-analysis demonstrated that LCC had markedly superior anti-EGFR mAb treatment benefit compared with RCC.
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Affiliation(s)
- Dandan Li
- Department of Pathology & Key Laboratory for Xinjiang Endemic & Ethnic Diseases, Shihezi University School of Medicine, Shihezi, Xinjiang, China.,Department of Pathology, The First Affiliated Hospital, Shihezi University School of Medicine, Shihezi, Xinjiang, China
| | - Qiang Fu
- Department of Hepatobiliary Pancreatic Surgery, People's Hospital of Zhengzhou University, Zhengzhou University School of Medicine, Zhengzhou, Henan, China
| | - Man Li
- Department of Pathology & Key Laboratory for Xinjiang Endemic & Ethnic Diseases, Shihezi University School of Medicine, Shihezi, Xinjiang, China.,Department of Pathology, The First Affiliated Hospital, Shihezi University School of Medicine, Shihezi, Xinjiang, China
| | - Jun Li
- Department of Pathology & Key Laboratory for Xinjiang Endemic & Ethnic Diseases, Shihezi University School of Medicine, Shihezi, Xinjiang, China.,Department of Pathology, The First Affiliated Hospital, Shihezi University School of Medicine, Shihezi, Xinjiang, China
| | - Can Yin
- Department of Pathology & Key Laboratory for Xinjiang Endemic & Ethnic Diseases, Shihezi University School of Medicine, Shihezi, Xinjiang, China.,Department of Pathology, The First Affiliated Hospital, Shihezi University School of Medicine, Shihezi, Xinjiang, China
| | - Jin Zhao
- Department of Pathology & Key Laboratory for Xinjiang Endemic & Ethnic Diseases, Shihezi University School of Medicine, Shihezi, Xinjiang, China.,Department of Pathology, The First Affiliated Hospital, Shihezi University School of Medicine, Shihezi, Xinjiang, China
| | - Feng Li
- Department of Pathology & Key Laboratory for Xinjiang Endemic & Ethnic Diseases, Shihezi University School of Medicine, Shihezi, Xinjiang, China.,Department of Pathology, The First Affiliated Hospital, Shihezi University School of Medicine, Shihezi, Xinjiang, China.,Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China.,Department of Pathology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
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20
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Abstract
GOALS To investigate trends in colorectal cancer (CRC) incidence and survival among Hispanics in Texas. BACKGROUND The incidence of CRC is rising among young adults in the United States. Given Texas' large Hispanic population, investigating CRC trends in Texas may provide valuable insight into the future of CRC epidemiology in an ever-diversifying US population. STUDY Data from the Texas Cancer Registry (1995 to 2010) were used to calculate age-adjusted CRC rates based on the 2000 US standard population. Annual percentage change (APC) and 5-year cancer-specific survival (CSS) rates were reported by age, race/ethnicity, stage, and anatomic location. RESULTS Of 123,083 CRC cases, 11% occurred in individuals below 50 years old, 26% of whom were Hispanic. Incidence was highest among African Americans (AAs; 76.3/100,000), followed by non-Hispanic whites (NHWs; 60.2/100,000) and Hispanics (50.8/100,000). Although overall CRC incidence declined between 1995 and 2010 (APC, -1.8%; P<0.01), trends differed by age and race/ethnicity. Among individuals 50 years and above, the rate of decline was statistically significant among NHWs (APC, -2.4%; P<0.01) and AAs (APC, -1.3%; P<0.01) but not among Hispanics (APC, -0.6%; P=0.13). In persons aged 20 to 39 years, CRC incidence rose significantly among Hispanics (APC, 2.6%; P<0.01) and NHWs (APC, 2.4%; P<0.01), but not AAs (APC, 0.3%; P=0.75). CSS rates among Hispanics and NHWs were comparable across most age groups and cancer stages, whereas CSS rates among AAs were generally inferior to those observed among NHWs and Hispanics. CONCLUSIONS Although CRC incidence has declined in Texas, it is rising among young Hispanics and NHWs while declining more slowly among older Hispanics than among older NHWs and AAs.
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21
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Kim J, Oh SW, Kim YS, Kwon H, Joh HK, Lee JE, Park D, Park JH, Ko AR, Kim YJ. Association between dietary fat intake and colorectal adenoma in korean adults: A cross-sectional study. Medicine (Baltimore) 2017; 96:e5759. [PMID: 28072719 PMCID: PMC5228679 DOI: 10.1097/md.0000000000005759] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The incidence of colorectal cancer is rapidly increasing in South Korea. It is important to clarify the association between colorectal cancer and diet, being one of the main modifiable risk factors, as such studies in the Korean population are lacking.A cross-sectional study was performed using data from participants who had undergone a screening colonoscopy and a nutritional assessment during a routine health check-up from January 2008 to December 2011. Dietary intake data were derived from 1-day food records; colorectal adenoma was histopathologically confirmed by biopsy during colonoscopy. Eventually, 2604 participants were included in the analysis. The risk of colorectal adenoma by quintile of dietary fat intake was analyzed using logistic regression. Subgroup analyses by degree of risk and by location of colorectal adenoma were additionally performed.In men, total fat intake was not associated with risk of colorectal adenoma. However, risk of colorectal adenoma increased with higher saturated fatty acid (SFA) intake. The adjusted odds ratio in the highest quintile was 1.71 (95% confidence interval, 1.01-2.91) compared with that in the lowest quintile. There was no significant association between fat intake and risk of colorectal adenoma characterized by subsite. In female participants, total fat and specific fatty acid intake were not associated with risk of colorectal adenoma.These data support that high SFA intake is associated with risk of colorectal adenoma in Korean men.
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Affiliation(s)
- Jeehyun Kim
- Department of Family Medicine, Seoul National University Hospital, Seoul, Korea
| | - Seung-Won Oh
- Department of Family Medicine, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul, Korea
| | - Young-Sun Kim
- Department of Internal Medicine, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul, Korea
| | - Hyuktae Kwon
- Department of Family Medicine, Seoul National University Hospital, Seoul, Korea
- Department of Family Medicine, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul, Korea
| | - Hee-Kyung Joh
- Department of Medicine, Seoul National University College of Medicine; Department of Family Medicine, Seoul National University Health Service Center, Seoul, Korea
| | - Ji-Eun Lee
- Department of Family Medicine, Seoul National University Hospital, Seoul, Korea
| | - Danbee Park
- Department of Family Medicine, Seoul National University Hospital, Seoul, Korea
| | - Jae-Hong Park
- Department of Family Medicine, Seoul National University Hospital, Seoul, Korea
| | - Ah-Ryoung Ko
- Department of Family Medicine, Seoul National University Hospital, Seoul, Korea
| | - Ye-Ji Kim
- Department of Family Medicine, Seoul National University Hospital, Seoul, Korea
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22
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Fahrer J, Kaina B. Impact of DNA repair on the dose-response of colorectal cancer formation induced by dietary carcinogens. Food Chem Toxicol 2016; 106:583-594. [PMID: 27693244 DOI: 10.1016/j.fct.2016.09.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 09/10/2016] [Accepted: 09/27/2016] [Indexed: 12/30/2022]
Abstract
Colorectal cancer (CRC) is one of the most frequently diagnosed cancers, which is causally linked to dietary habits, notably the intake of processed and red meat. Processed and red meat contain dietary carcinogens, including heterocyclic aromatic amines (HCAs) and N-nitroso compounds (NOC). NOC are agents that induce various N-methylated DNA adducts and O6-methylguanine (O6-MeG), which are removed by base excision repair (BER) and O6-methylguanine-DNA methyltransferase (MGMT), respectively. HCAs such as the highly mutagenic 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) cause bulky DNA adducts, which are removed from DNA by nucleotide excision repair (NER). Both O6-MeG and HCA-induced DNA adducts are linked to the occurrence of KRAS and APC mutations in colorectal tumors of rodents and humans, thereby driving CRC initiation and progression. In this review, we focus on DNA repair pathways removing DNA lesions induced by NOC and HCA and assess their role in protecting against mutagenicity and carcinogenicity in the large intestine. We further discuss the impact of DNA repair on the dose-response relationship in colorectal carcinogenesis in view of recent studies, demonstrating the existence of 'no effect' point of departures (PoDs), i.e. thresholds for genotoxicity and carcinogenicity. The available data support the threshold concept for NOC with DNA repair being causally involved.
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Affiliation(s)
- Jörg Fahrer
- Department of Toxicology, University Medical Center Mainz, Obere Zahlbacher Strasse 67, D-55131 Mainz, Germany.
| | - Bernd Kaina
- Department of Toxicology, University Medical Center Mainz, Obere Zahlbacher Strasse 67, D-55131 Mainz, Germany.
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23
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Räz MH, Dexter HR, Millington CL, van Loon B, Williams DM, Sturla SJ. Bypass of Mutagenic O(6)-Carboxymethylguanine DNA Adducts by Human Y- and B-Family Polymerases. Chem Res Toxicol 2016; 29:1493-503. [PMID: 27404553 DOI: 10.1021/acs.chemrestox.6b00168] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The generation of chemical alkylating agents from nitrosation of glycine and bile acid conjugates in the gastrointestinal tract is hypothesized to initiate carcinogenesis. O(6)-carboxymethylguanine (O(6)-CMG) is a product of DNA alkylation derived from nitrosated glycine. Although the tendency of the structurally related adduct O(6)-methylguanine to code for the misincoporation of TTP during DNA replication is well-established, the impact of the presence of the O(6)-CMG adduct in a DNA template on the efficiency and fidelity of translesion DNA synthesis (TLS) by human DNA polymerases (Pols) has hitherto not been described. Herein, we characterize the ability of the four human TLS Pols η, ι, κ, and ζ and the replicative Pol δ to bypass O(6)-CMG in a prevalent mutational hot-spot for colon cancer. The results indicate that Pol η replicates past O(6)-CMG, incorporating dCMP or dAMP, whereas Pol κ incorporates dCMP only, and Pol ι incorporates primarily dTMP. Additionally, the subsequent extension step was carried out with high efficiency by TLS Pols η, κ, and ζ, while Pol ι was unable to extend from a terminal mismatch. These results provide a first basis of O(6)-CMG-promoted base misincorporation by Y- and B-family polymerases potentially leading to mutational signatures associated with colon cancer.
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Affiliation(s)
- Michael H Räz
- Department of Health Sciences and Technology, ETH Zürich , Schmelzbergstrasse 9, 8092 Zürich, Switzerland
| | - Hannah R Dexter
- Center for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield , Sheffield S3 7HF, United Kingdom
| | - Christopher L Millington
- Center for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield , Sheffield S3 7HF, United Kingdom
| | - Barbara van Loon
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology (NTNU) , Erling Skjalgssons gate 1, 7491 Trondheim, Norway
| | - David M Williams
- Center for Chemical Biology, Department of Chemistry, Krebs Institute, University of Sheffield , Sheffield S3 7HF, United Kingdom
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zürich , Schmelzbergstrasse 9, 8092 Zürich, Switzerland
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Tikhonov EA. Structural Changes in Large Intestinal Aggregated Lymphoid Follicles in Wistar Rats During Postnatal Ontogeny. Bull Exp Biol Med 2015; 159:662-5. [PMID: 26463055 DOI: 10.1007/s10517-015-3042-2] [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: 03/03/2015] [Indexed: 10/22/2022]
Abstract
Quantitative evaluation of aggregated lymphoid follicles in various compartments of the large intestine was carried out in Wistar rats of different age: newborn (3-4 days), prepubertal (20-30 days), adult (2-3 months), and old (16-18 months). No aggregated lymphoid tissue was detected in the large intestinal mucosa of newborn animals. The cecum of prepubertal, adult, and old animals contained solitary patches with 7-9 follicles. Higher percentage of aggregated lymphoid tissue, associated with colonic mucosa, was explained by enlargement of the lymphoid patch area and of the number of solitary lymphoid follicles during the postnatal ontogenesis. The mean area of a patch in the distal part of the colon in prepubertal, adult, and old animals was 3.2, 2.5, and 2.2 times larger than in the medial part of the intestine, the number of follicles per patch was 2.8, 2.8, and 2.5 times higher, respectively. The differences were significant only for the two younger groups.
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Affiliation(s)
- E A Tikhonov
- Research Institute of Human Morphology, Russian Academy of Sciences, Moscow, Russia.
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Butyrylated starch intake can prevent red meat-induced O6-methyl-2-deoxyguanosine adducts in human rectal tissue: a randomised clinical trial. Br J Nutr 2015; 114:220-30. [PMID: 26084032 PMCID: PMC4531472 DOI: 10.1017/s0007114515001750] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Epidemiological studies have identified increased colorectal cancer (CRC) risk with high red meat (HRM) intakes, whereas dietary fibre intake appears to be protective. In the present study, we examined whether a HRM diet increased rectal O(6)-methyl-2-deoxyguanosine (O(6)MeG) adduct levels in healthy human subjects, and whether butyrylated high-amylose maize starch (HAMSB) was protective. A group of twenty-three individuals consumed 300 g/d of cooked red meat without (HRM diet) or with 40 g/d of HAMSB (HRM+HAMSB diet) over 4-week periods separated by a 4-week washout in a randomised cross-over design. Stool and rectal biopsy samples were collected for biochemical, microbial and immunohistochemical analyses at baseline and at the end of each 4-week intervention period. The HRM diet increased rectal O(6)MeG adducts relative to its baseline by 21% (P < 0.01), whereas the addition of HAMSB to the HRM diet prevented this increase. Epithelial proliferation increased with both the HRM (P < 0.001) and HRM + HAMSB (P < 0.05) diets when compared with their respective baseline levels, but was lower following the HRM + HAMSB diet compared with the HRM diet (P < 0.05). Relative to its baseline, the HRM + HAMSB diet increased the excretion of SCFA by over 20% (P < 0.05) and increased the absolute abundances of the Clostridium coccoides group (P < 0.05), the Clostridium leptum group (P < 0.05), Lactobacillus spp. (P < 0.01), Parabacteroides distasonis (P < 0.001) and Ruminococcus bromii (P < 0.05), but lowered Ruminococcus torques (P < 0.05) and the proportions of Ruminococcus gnavus, Ruminococcus torques and Escherichia coli (P < 0.01). HRM consumption could increase the risk of CRC through increased formation of colorectal epithelial O(6)MeG adducts. HAMSB consumption prevented red meat-induced adduct formation, which may be associated with increased stool SCFA levels and/or changes in the microbiota composition.
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N-3 polyunsaturated fatty acids intake and risk of colorectal cancer: meta-analysis of prospective studies. Cancer Causes Control 2014; 26:133-41. [PMID: 25416450 DOI: 10.1007/s10552-014-0492-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 11/04/2014] [Indexed: 12/14/2022]
Abstract
BACKGROUND Growing body of laboratory evidence supports the beneficial effects of n-3 polyunsaturated fatty acids (PUFAs) on colorectal cancer (CRC) prevention. Epidemiologic studies investigating the relationship between n-3 PUFAs intake and risk of CRC, however, have been inconsistent. We aimed to clarify the relation by conducting a meta-analysis of prospective studies. METHODS Eligible studies were identified by searching PubMed database and by carefully reviewing bibliographies of retrieved publications. Summary relative risks (RRs) with their 95 % confidence intervals (CIs) were computed with a random-effects model. Subgroup, meta-regression, and dose-response analyses were performed to explore potential sources of heterogeneity. RESULTS A total of 14 prospective studies involving 8,775 cancer cases were included in the final analysis. Overall, total n-3 or marine PUFAs intake was not associated with risk of CRC (RR 0.99 and 1.00). However, there was a trend toward reduced risk of proximal colon cancer (total n-3 PUFAs: RR 0.83, 95 % CI 0.66-1.05; marine PUFAs: RR 0.81, 95 % CI 0.59-1.10) and a significant increased risk of distal colon cancer (total n-3 PUFAs: RR 1.26, 95 % CI 1.06-1.50; marine PUFAs: RR 1.38, 95 % CI 1.11-1.71). Furthermore, marine PUFAs intake accessed longer before diagnosis was associated 21 % reduced risk of CRC (RR 0.79, 95 % CI 0.63-1.00). CONCLUSION Overall, this meta-analysis finds no relation between n-3 PUFAs intake and risk of CRC. The observed subsite heterogeneity within colon cancer and the possible effect modification by latency time merit further studies.
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Is right-sided colon cancer different to left-sided colorectal cancer? - a systematic review. Eur J Surg Oncol 2014; 41:300-8. [PMID: 25468456 DOI: 10.1016/j.ejso.2014.11.001] [Citation(s) in RCA: 273] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 11/03/2014] [Indexed: 11/21/2022] Open
Abstract
Colorectal cancer (CRC) exhibits differences in incidence, pathogenesis, molecular pathways and outcome depending on the location of the tumor. This review focuses on the latest developments in epidemiological and scientific studies, which have enhanced our understanding on the underlying genetic and immunological differences between the proximal (right-sided) colon and the distal (left-sided) colorectum. The different ways in which environmental risk factors influence the pathogenesis of CRC depending on its location and the variations in surgical and oncological outcomes are also discussed in this review. In the current era of personalized medicine, we aim to reiterate the importance of tumor location in management of CRC and the implication on future clinical and scientific research.
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Zhang F, Tsunoda M, Kikuchi Y, Wilkinson O, Millington CL, Margison GP, Williams DM, Takénaka A. O6-Carboxymethylguanine in DNA forms a sequence context-dependent wobble base-pair structure with thymine. ACTA ACUST UNITED AC 2014; 70:1669-79. [DOI: 10.1107/s1399004714006178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 03/19/2014] [Indexed: 11/10/2022]
Abstract
N-Nitrosation of glycine and its derivatives generates potent alkylating agents that can lead to the formation ofO6-carboxymethylguanine (O6-CMG) in DNA.O6-CMG has been identified in DNA derived from human colon tissue and its occurrence has been linked to diets high in red and processed meats, implying an association with the induction of colorectal cancer. By analogy toO6-methylguanine,O6-CMG is expected to be mutagenic, inducing G-to-A mutations that may be the molecular basis of increased cancer risk. Previously, the crystal structure of the DNA dodecamer d(CGCG[O6-CMG]ATTCGCG) has been reported, in whichO6-CMG forms a Watson–Crick-type pair with thymine similar to the canonical A:T pair. In order to further investigate the versatility ofO6-CMG in base-pair formation, the structure of the DNA dodecamer d(CGC[O6-CMG]AATTTGCG) containingO6-CMG at a different position has been determined by X-ray crystallography using four crystal forms obtained under conditions containing different solvent ions (Sr2+, Ba2+, Mg2+, K+or Na+) with and without Hoechst 33258. The most striking finding is that the pairing modes ofO6-CMG with T are quite different from those previously reported. In the present dodecamer, the T bases are displaced (wobbled) into the major groove to form a hydrogen bond between the thymine N3N—H and the carboxyl group ofO6-CMG. In addition, a water molecule is bridged through two hydrogen bonds between the thymine O2atom and the 2-amino group ofO6-CMG to stabilize the pairing. These interaction modes commonly occur in the four crystal forms, regardless of the differences in crystallization conditions. The previous and the present results show thatO6-CMG can form a base pair with T in two alternative modes: the Watson–Crick type and a high-wobble type, the nature of which may depend on the DNA-sequence context.
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Repair and removal of azoxymethane-induced O6-methylguanine in rat colon by O6-methylguanine DNA methyltransferase and apoptosis. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2013; 758:80-6. [DOI: 10.1016/j.mrgentox.2013.10.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/30/2013] [Accepted: 10/04/2013] [Indexed: 11/23/2022]
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30
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Gilsing AMJ, Fransen F, de Kok TM, Goldbohm AR, Schouten LJ, de Bruïne AP, van Engeland M, van den Brandt PA, de Goeij AFPM, Weijenberg MP. Dietary heme iron and the risk of colorectal cancer with specific mutations in KRAS and APC. Carcinogenesis 2013; 34:2757-66. [PMID: 23983135 DOI: 10.1093/carcin/bgt290] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Red meat intake has been linked to increased colorectal cancer (CRC) risk. Although the underlying mechanisms remain unclear, experimental studies suggest a role for dietary heme iron. Because heme iron was shown to promote specific mutations, it would be insightful to link heme iron data to CRC with mutations in key genes in an observational, population-based study. We investigated the association between dietary heme iron intake and risk of CRC with mutations in APC (adenomatous polyposis coli) and KRAS (Kirsten ras) and P53 overexpression in the Netherlands Cohort Study. After 7.3 years of follow-up, excluding the first 2.3 years due to incomplete coverage of the pathology registry and to avoid preclinical disease, adjusted hazard ratios (including adjustment for total meat) and 95% confidence intervals were calculated, using 4026 subcohort members (aged 55-69 years at baseline), 435 colon and 140 rectal cancer patients. When comparing the highest with the lowest tertile of intake, heme iron intake was associated with an increased risk of CRC harboring activating mutations in KRAS (hazard ratio = 1.71, 95% confidence interval: 1.15-2.57; P for trend = 0.03) and CRC without truncating mutations in APC (hazard ratio = 1.79, 95% confidence interval: 1.23-2.60; P for trend = 0.003). We observed a positive association between heme iron intake and the risk of CRC with activating G>A mutations in KRAS (P for trend = 0.01) and overall G>A mutations in APC (P for trend = 0.005). No associations were found with CRC harboring G>T mutations in KRAS/APC. Heme iron intake was positively associated with the risk of P53 overexpressed tumors but not with tumors without P53 overexpression (Pheterogeneity = 0.12). Heme iron intake was associated with an increased risk of colorectal tumors harboring G>A transitions in KRAS and APC and overexpression of P53. These novel findings suggest that alkylating rather than oxidative DNA-damaging mechanisms are involved in heme-induced colorectal carcinogenesis.
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Fahrer J, Kaina B. O6-methylguanine-DNA methyltransferase in the defense against N-nitroso compounds and colorectal cancer. Carcinogenesis 2013; 34:2435-42. [PMID: 23929436 DOI: 10.1093/carcin/bgt275] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Colorectal cancer (CRC) is among the leading causes of cancer death worldwide, involving multiple dietary and non-dietary risk factors. A growing body of evidence suggests that N-nitroso compounds (NOC) play a pivotal role in the etiology of CRC. NOC are present in food and are also formed endogenously in the large intestine. Upon metabolic activation and also spontaneously, they form electrophilic species that methylate the DNA, producing N-methylated purines and O(6)-methylguanine, the latter of which bears high mutagenic and carcinogenic potential. Methylated DNA bases are removed by base excision repair initiated by the alkyladenine-DNA glycosylase, the family of AlkB homologs proteins, and the suicide enzyme O(6)-methylguanine-DNA methyltransferase (MGMT), which is the main focus of this review. We present animal models with a deficiency of MGMT that display a tremendously enhanced sensitivity toward alkylation-induced colorectal carcinogenesis, highlighting its role in the protection against the cytotoxic and mutagenic effects of alkylating agents. In line with these studies, MGMT was linked to the formation of human sporadic CRC. Colorectal tumors and precursor lesions frequently display epigenetic inactivation of MGMT resulting from promoter hypermethylation, which is tightly associated with the occurrence of G:C to A:T transition mutations in the KRAS oncogene. We also discuss clinical data, which identified the MGMT status of CRC patients as promising parameter for the treatment of metastasized CRC using alkylating anticancer drugs such as temozolomide.
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Affiliation(s)
- Jörg Fahrer
- Department of Toxicology, University Medical Center Mainz, Obere Zahlbacher Strasse 67, D-55131 Mainz, Germany
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Zhang F, Tsunoda M, Suzuki K, Kikuchi Y, Wilkinson O, Millington CL, Margison GP, Williams DM, Czarina Morishita E, Takénaka A. Structures of DNA duplexes containing O6-carboxymethylguanine, a lesion associated with gastrointestinal cancer, reveal a mechanism for inducing pyrimidine transition mutations. Nucleic Acids Res 2013; 41:5524-32. [PMID: 23580550 PMCID: PMC3664797 DOI: 10.1093/nar/gkt198] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
N-nitrosation of glycine and its derivatives generates potent alkylating agents that can lead to the formation of O(6)-carboxymethylguanine (O(6)-CMG) in DNA. O(6)-CMG has been identified in DNA derived from human colon tissue, and its occurrence has been linked to diets high in red and processed meats. By analogy to O(6)-methylguanine, O(6)-CMG is expected to be highly mutagenic, inducing G to A mutations during DNA replication that can increase the risk of gastrointestinal and other cancers. Two crystal structures of DNA dodecamers d(CGCG[O(6)-CMG]ATTCGCG) and d(CGC[O(6)-CMG]AATTCGCG) in complex with Hoechst33258 reveal that each can form a self-complementary duplex to retain the B-form conformation. Electron density maps clearly show that O(6)-CMG forms a Watson-Crick-type pair with thymine similar to the canonical A:T pair, and it forms a reversed wobble pair with cytosine. In situ structural modeling suggests that a DNA polymerase can accept the Watson-Crick-type pair of O(6)-CMG with thymine, but might also accept the reversed wobble pair of O(6)-CMG with cytosine. Thus, O(6)-CMG would permit the mis-incorporation of dTTP during DNA replication. Alternatively, the triphosphate that would be formed by carboxymethylation of the nucleotide triphosphate pool d[O(6)-CMG]TP might compete with dATP incorporation opposite thymine in a DNA template.
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Affiliation(s)
- Fang Zhang
- Graduate School of Science and Engineering, Iwaki-Meisei University, Iwaki 970-8551, Japan
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Subsite-specific dietary risk factors for colorectal cancer: a review of cohort studies. JOURNAL OF ONCOLOGY 2013; 2013:703854. [PMID: 23577027 PMCID: PMC3610350 DOI: 10.1155/2013/703854] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 11/30/2012] [Indexed: 02/08/2023]
Abstract
Objective. A shift in the total incidence from left- to right-sided colon cancer has been reported and raises the question as to whether lifestyle risk factors are responsible for the changing subsite distribution of colon cancer. The present study provides a review of the subsite-specific risk estimates for the dietary components presently regarded as convincing or probable risk factors for colorectal cancer: red meat, processed meat, fiber, garlic, milk, calcium, and alcohol. Methods. Studies were identified by searching PubMed through October 8, 2012 and by reviewing reference lists. Thirty-two prospective cohort studies are included, and the estimates are compared by sex for each risk factor. Results. For alcohol, there seems to be a stronger association with rectal cancer than with colon cancer, and for meat a somewhat stronger association with distal colon and rectal cancer, relative to proximal colon cancer. For fiber, milk, and calcium, there were only minor differences in relative risk across subsites. No statement could be given regarding garlic. Overall, many of the subsite-specific risk estimates were nonsignificant, irrespective of exposure. Conclusion. For some dietary components the associations with risk of cancer of the rectum and distal colon appear stronger than for proximal colon, but not for all.
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Senthong P, Millington CL, Wilkinson OJ, Marriott AS, Watson AJ, Reamtong O, Eyers CE, Williams DM, Margison GP, Povey AC. The nitrosated bile acid DNA lesion O6-carboxymethylguanine is a substrate for the human DNA repair protein O6-methylguanine-DNA methyltransferase. Nucleic Acids Res 2013; 41:3047-55. [PMID: 23335782 PMCID: PMC3597670 DOI: 10.1093/nar/gks1476] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The consumption of red meat is a risk factor in human colorectal cancer (CRC). One hypothesis is that red meat facilitates the nitrosation of bile acid conjugates and amino acids, which rapidly convert to DNA-damaging carcinogens. Indeed, the toxic and mutagenic DNA adduct O6-carboxymethylguanine (O6-CMG) is frequently present in human DNA, increases in abundance in people with high levels of dietary red meat and may therefore be a causative factor in CRC. Previous reports suggested that O6-CMG is not a substrate for the human version of the DNA damage reversal protein O6-methylguanine-DNA methyltransferase (MGMT), which protects against the genotoxic effects of other O6-alkylguanine lesions by removing alkyl groups from the O6-position. We now show that synthetic oligodeoxyribonucleotides containing the known MGMT substrate O6-methylguanine (O6-MeG) or O6-CMG effectively inactivate MGMT in vitro (IC50 0.93 and 1.8 nM, respectively). Inactivation involves the removal of the O6-alkyl group and its transfer to the active-site cysteine residue of MGMT. O6-CMG is therefore an MGMT substrate, and hence MGMT is likely to be a protective factor in CRC under conditions where O6-CMG is a potential causative agent.
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Affiliation(s)
- Pattama Senthong
- Centre for Occupational and Environmental Health, Faculty of Medical & Human Sciences, University of Manchester, Manchester M13 9PL, UK
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35
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Miller PE, Lazarus P, Lesko SM, Cross AJ, Sinha R, Laio J, Zhu J, Harper G, Muscat JE, Hartman TJ. Meat-related compounds and colorectal cancer risk by anatomical subsite. Nutr Cancer 2013; 65:202-26. [PMID: 23441608 PMCID: PMC3584417 DOI: 10.1080/01635581.2013.756534] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Since meat may be involved in the etiology of colorectal cancer, associations between meat-related compounds were examined to elucidate underlying mechanisms in a population-based case-control study. Participants (989 cases/1,033 healthy controls) completed a food frequency questionnaire with a meat-specific module. Multivariable logistic regression was used to examine associations between meat variables and colorectal cancer; polytomous logistic regression was used for subsite-specific analyses. The following significant positive associations were observed for meat-related compounds: 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx) and colorectal, distal colon, and rectal tumors; 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and colorectal and colon cancer tumors; nitrites/nitrates and proximal colon cancer; 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and rectal cancer; and benzo[a]pyrene and rectal cancer (P-trends < 0.05). For analyses by meat type, cooking method, and doneness preference, positive associations between red processed meat and proximal colon cancer and pan-fried red meat and colorectal cancer were found (P-trends < 0.05). Inverse associations were observed between unprocessed poultry and colorectal, colon, proximal colon, and rectal tumors; grilled/barbequed poultry and proximal colon cancer; and well-done/charred poultry and colorectal, colon, and proximal colon tumors (P-trends < 0.05). HCAs, PAHs, nitrites, and nitrates may be involved in colorectal cancer etiology. Further examination into the unexpected inverse associations between poultry and colorectal cancer is warranted.
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Affiliation(s)
- Paige E Miller
- Cancer Prevention Fellowship Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
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Water extracts of tree Hypericum sps. protect DNA from oxidative and alkylating damage and enhance DNA repair in colon cells. Food Chem Toxicol 2013; 51:80-6. [DOI: 10.1016/j.fct.2012.09.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/07/2012] [Accepted: 09/11/2012] [Indexed: 02/07/2023]
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Ramos AA, Pedro D, Collins AR, Pereira-Wilson C. Protection by Salvia extracts against oxidative and alkylation damage to DNA in human HCT15 and CO115 cells. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2012; 75:765-75. [PMID: 22788364 DOI: 10.1080/15287394.2012.689804] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
DNA damage induced by oxidative and alkylating agents contributes to carcinogenesis, leading to possible mutations if replication proceeds without proper repair. However, some alkylating agents are used in cancer therapy due to their ability to induce DNA damage and subsequently apoptosis of tumor cells. In this study, the genotoxic effects of oxidative hydrogen peroxide (H₂O₂) and alkylating agents N-methyl-N-nitrosourea (MNU) and 1,3-bis-(2-chloroethyl)-1-nitosourea (BCNU) agents were examined in two colon cell lines (HCT15 and CO115). DNA damage was assessed by the comet assay with and without lesion-specific repair enzymes. Genotoxic agents were used for induction of DNA damage in both cell lines. Protective effects of extracts of three Salvia species, Salvia officinalis (SO), Salvia fruticosa (SF), and Salvia lavandulifolia (SL), against DNA damage induced by oxidative and alkylating agents were also determined. SO and SF protected against oxidative DNA damage in HCT15 cells. SO and SL decreased DNA damage induced by MNU in CO115 cells. In addition to chemopreventive effects of sage plant extracts, it was also important to know whether these plant extracts may interfere with alkylating agents such as BCNU used in cancer therapy, decreasing their efficacy. Our results showed that sage extracts tested and rosmarinic acid (RA), the main constituent, protected CO115 cells from DNA damage induced by BCNU. In HCT15 cells, only SF induced a reduction in BCNU-induced DNA damage. Sage water extracts and RA did not markedly change DNA repair protein expression in either cell line. Data showed that sage tea protected colon cells against oxidative and alkylating DNA damage and may also interfere with efficacy of alkylating agents used in cancer therapy.
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Affiliation(s)
- Alice A Ramos
- CBMA-Centre of Molecular and Environmental Biology/Department of Biology, School of Sciences, University of Minho, Braga, Portugal
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Gay LJ, Arends MJ, Mitrou PN, Bowman R, Ibrahim AE, Happerfield L, Luben R, McTaggart A, Ball RY, Rodwell SA. MLH1 promoter methylation, diet, and lifestyle factors in mismatch repair deficient colorectal cancer patients from EPIC-Norfolk. Nutr Cancer 2011; 63:1000-10. [PMID: 21875327 DOI: 10.1080/01635581.2011.596987] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
There is conflicting evidence for the role diet and lifestyle play in the development of mismatch repair (MMR)-deficient colorectal cancers (CRC). In this study, associations between MMR deficiency, clinicopathological characteristics, and dietary and lifestyle factors in sporadic CRC were investigated. Tumor samples from 185 individuals in the EPIC-Norfolk study were analyzed for MLH1 gene promoter methylation and microsatellite instability (MSI). Dietary and lifestyle data were collected prospectively using 7-day food diaries (7dd) and questionnaires. MMR-deficient tumor cases (MLH1 promoter methylation positive, MSI-H) were more likely to be female, older at diagnosis, early Dukes' stage (A/B), and proximal in location (MSI-H P = 0.03, 0.03, 0.02, and 0.001, respectively). Tumors with positive MLH1 promoter methylation (>20%) were associated with poor differentiation (P = 0.03). Low physical activity was associated with cases without MSI (P = 0.05). MMR deficiency was not significantly associated with cigarette smoking or alcohol, folate, fruit, vegetable, or meat consumption. We conclude that MMR-deficient tumors represent a distinct subset of sporadic CRC that are proximal in location, early Dukes' stage, and poorly differentiated, in cases that are female and older at diagnosis. There is no overall role for diet and lifestyle in MMR status in CRC, consistent with age-related susceptibility to MLH1 promoter methylation.
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Affiliation(s)
- Laura J Gay
- Medical Research Council Dunn Human Nutrition Unit, Cambridge, United Kingdom
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Sakai E, Takahashi H, Kato S, Uchiyama T, Hosono K, Endo H, Maeda S, Yoneda M, Taguri M, Nakajima A. Investigation of the prevalence and number of aberrant crypt foci associated with human colorectal neoplasm. Cancer Epidemiol Biomarkers Prev 2011; 20:1918-24. [PMID: 21750169 DOI: 10.1158/1055-9965.epi-11-0104] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Aberrant crypt foci (ACF) are considered to be useful as surrogate biomarker for colorectal cancer (CRC), but the biological significance of ACF remains controversial. We attempted to investigate the relationship between the presence of ACF and human colorectal carcinogenesis using a relatively large sample size. METHODS We carried out high-magnification chromoscopic colonoscopy to identify ACFs in 861 subjects undergoing a diagnostic endoscopy at the Yokohama City University Hospital. The present study compared the prevalence and number of ACFs in three subject groups (normal subjects, adenoma cases, and CRC cases). The correlations between the demographic and behavioral characteristics of the subjects and the prevalence of ACFs were also assessed. RESULTS The prevalence of ACF was 64%, 88%, and 95%, and the mean number of ACF was 3.6, 6.2, and 10.1, in normal subjects, adenoma cases, and CRC cases, respectively. When differences in the prevalence and number of ACFs among age- and sex-stratified subject groups were examined, significant stepwise increments from normal subjects to adenoma cases to CRC cases were apparent (P < 0.001). Moreover, an age- and sex-adjusted multiple logistic regression analysis revealed that smoking and alcohol habits had a synergistic effect, increasing the prevalence of ACFs as well as the risk of CRC (P < 0.001). CONCLUSIONS These results suggested that ACF may serve as a reliable surrogate biomarker for human colorectal carcinogenesis. IMPACT The use of ACF as an endpoint may enable the size, duration, and cost of CRC chemoprevention studies to be reduced.
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Affiliation(s)
- Eiji Sakai
- Gastroenterology Division, Yokohama City University School of Medicine, 3-9 Fuku-ura, Kanazawa-ku, Yokohama, 236-0004 Japan
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Nilsson R. The molecular basis for induction of human cancers by tobacco specific nitrosamines. Regul Toxicol Pharmacol 2011; 60:268-80. [DOI: 10.1016/j.yrtph.2011.02.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 02/24/2011] [Accepted: 02/28/2011] [Indexed: 10/18/2022]
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Sasazuki S, Inoue M, Iwasaki M, Sawada N, Shimazu T, Yamaji T, Takachi R, Tsugane S. Intake of n-3 and n-6 polyunsaturated fatty acids and development of colorectal cancer by subsite: Japan Public Health Center-based prospective study. Int J Cancer 2011; 129:1718-29. [PMID: 21120874 DOI: 10.1002/ijc.25802] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 11/03/2010] [Indexed: 11/10/2022]
Abstract
To date, epidemiologic studies investigating intake of n-3 and n-6 polyunsaturated fatty acids and risk of colorectal cancer are limited, and results remain inconsistent. This is the first prospective study to show the association by subsite (proximal colon, distal colon, rectum). To clarify the role of n-3 and n-6 polyunsaturated fatty acids intake in colon carcinogenesis, we conducted a large, population-based prospective study, characterized by high fish consumption and a wide range of n-3 polyunsaturated fatty acids intakes. Subjects were followed from response to a lifestyle questionnaire in 1995-1999 through 2006. During 827,833 person-years of follow-up (average 9.3 years), we identified 1,268 new colorectal cancer cases (521 colon and 253 rectal for men; 350 colon and 144 rectal for women). Compared to the lowest quintile, the relative risk and 95% confidence interval of developing cancer among the fifth quintile of marine n-3 polyunsaturated fatty acids intake were 0.60 and 0.31-1.14, respectively (p for trend = 0.04) in the colon in women and 0.35 and 0.14-0.88 (p for trend = 0.05) and 1.82 and 0.79-4.20 (p for trend = 0.16) in the proximal and distal colon, respectively, in men. For rectal cancer, the dose response for marine n-3 polyunsaturated fatty acids s was unclear; rather, we observed U-shaped associations in men and women. We found no evidence that n-6 polyunsaturated fatty acids increases or the n-3/n-6 ratio decreases the risk of colorectal cancer. Our results suggest that intake of marine n-3 polyunsaturated fatty acids may be inversely related to the risk of cancer in the proximal site of the large bowel.
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Affiliation(s)
- Shizuka Sasazuki
- Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
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Is the tissue persistence of O6-methyl-2′-deoxyguanosine an indicator of tumour formation in the gastrointestinal tract? MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2011; 721:119-26. [DOI: 10.1016/j.mrgentox.2010.12.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 11/09/2010] [Accepted: 12/23/2010] [Indexed: 11/21/2022]
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Billson HA, Harrison KL, Lees NP, Hall CN, Margison GP, Povey AC. Dietary variables associated with DNA N7-methylguanine levels and O6-alkylguanine DNA-alkyltransferase activity in human colorectal mucosa. Carcinogenesis 2009; 30:615-20. [PMID: 19168588 DOI: 10.1093/carcin/bgp020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Components of human diets may influence the incidence of colorectal adenomas, by modifying exposure or susceptibility to DNA-damaging alkylating agents. To examine this hypothesis, a food frequency questionnaire was used to assess the diet of patients recruited for a case-referent study where biopsies of normal colorectal mucosa were collected during colonoscopy and subsequently analysed for DNA N7-methylguanine (N7-MeG) levels, as an indicator of exposure, and activity of the DNA repair protein O6-alkylguanine DNA-alkyltransferase (MGMT), as an indicator of potential susceptibility. Cases with histologically proven colorectal adenomas (n = 38) were compared with referents (n = 35) free of gastrointestinal neoplasia. The case group consumed significantly more red meat (4.5 versus 3.4 servings/week, P < 0.05), processed meats, (4.7 versus 3.2 servings/week, P < 0.05) and % food energy as fat (34.9 versus 30.7%, P < 0.001). N7-MeG [mean: 95% confidence interval (CI)] levels were significantly lower in the group that consumed the highest proportion of dietary fibre/1000 kcal in comparison with the group with the lowest intake (0.61; 0.35-0.86 versus 1.88; 0.88-2.64 micromol/mol dG, P < 0.05). N7-MeG levels were also inversely associated with folate consumption (P < 0.05). MGMT activity (mean; 95% CI) was significantly higher in the group with the lowest consumption of vegetables than in the group with the greatest vegetable consumption (7.02; 5.70-8.33 versus 4.93; 3.95-5.91 fmol/microg DNA, P < 0.05). Our results are consistent with the hypothesis that dietary factors may modify exposure or susceptibility, respectively, to DNA damage by alkylating agents.
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Affiliation(s)
- H A Billson
- Occupational and Environmental Health Research Group, School of Translational Medicine, University of Manchester, Manchester M13 9PL, UK
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Morita M, Tabata S, Tajima O, Yin G, Abe H, Kono S. Genetic polymorphisms of CYP2E1 and risk of colorectal adenomas in the Self Defense Forces Health Study. Cancer Epidemiol Biomarkers Prev 2008; 17:1800-7. [PMID: 18628434 DOI: 10.1158/1055-9965.epi-08-0314] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
CYP2E1 is an enzyme involved in the metabolism of N-nitrosamines and other carcinogenic substances. Functional RsaI and 96-bp insertion polymorphisms in 5'-flanking region have drawn interest in relation to the risk of colorectal cancer. We investigated the relation of these genetic polymorphisms and colorectal adenoma, a well-established precursor lesion of colorectal cancer. Subjects were 455 cases of colorectal adenomas and 1,052 controls of normal colonoscopy among men receiving a preretirement health examination in the Self Defense Forces. Genotypes were determined by either PCR-RFLP or PCR method. Statistical adjustment was made for smoking, alcohol use, body mass index, physical activity, and others. Individuals with RsaI c2 allele showed a decreased risk of proximal colon adenomas; adjusted odds ratios (95% confidence interval) of proximal and distal adenomas for the c1/c2 or c2/c2 genotype versus c1/c1 was 0.61 (0.41-0.88) and 0.95 (0.71-1.27), respectively. CYP2E1 96-bp insertion allele was associated with an increased risk of large (> or = 5 mm) adenomas; adjusted odds ratios (95% confidence interval) of large and small adenomas for having at least one insertion allele were 1.41 (1.03-1.94) and 0.94 (0.71-1.25), respectively. A suggestive effect modification was noted for alcohol consumption on the association between RsaI polymorphism and proximal adenomas (P(interaction) = 0.09) as well as on the association between 96-bp insertion and large adenomas (P(interaction) = 0.05). These findings indicate that variation in activity and inducibility of CYP2E1 contribute to the development of colorectal carcinogenesis.
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Affiliation(s)
- Makiko Morita
- Department of Preventive Medicine, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan.
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Suehiro Y, Wong CW, Chirieac LR, Kondo Y, Shen L, Webb CR, Chan YW, Chan ASY, Chan TL, Wu TT, Rashid A, Hamanaka Y, Hinoda Y, Shannon RL, Wang X, Morris J, Issa JPJ, Yuen ST, Leung SY, Hamilton SR. Epigenetic-genetic interactions in the APC/WNT, RAS/RAF, and P53 pathways in colorectal carcinoma. Clin Cancer Res 2008; 14:2560-9. [PMID: 18451217 DOI: 10.1158/1078-0432.ccr-07-1802] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE Early events in colorectal tumorigenesis include mutation of the adenomatous polyposis coli (APC) gene and epigenetic hypermethylation with transcriptional silencing of the O(6)-methylguanine DNA methyltransferase (MGMT), human mut L homologue 1 (hMLH1), and P16/CDKN2A genes. Epigenetic alterations affect genetic events: Loss of MGMT via hypermethylation reportedly predisposes to guanine-to-adenine or cytosine-to-thymine (G:C-->A:T) transition mutations in KRAS and P53, and silencing of hMLH1 leads to high levels of microsatellite instability (MSI-H)/mutator phenotype, suggesting that epigenetic-genetic subtypes exist. EXPERIMENTAL DESIGN We evaluated the relationships of aberrant methylation of APC, MGMT, hMLH1, P16, N33, and five MINTs to mutations in APC, KRAS, BRAF, and P53 in 208 colorectal carcinomas. RESULTS We found that APC hypermethylation was age related (P = 0.04), in contrast to the other genes, and did not cluster with CpG island methylator phenotype (CIMP) markers. Hypermethylation of APC concurrently with either MGMT or hMLH1 was strongly associated with occurrence of G-to-A transitions in APC [odds ratio (OR), 26.8; P < 0.0002 from multivariable logic regression model], but C-to-T transitions had no associations. There was no relationship of hypermethylation of any gene, including MGMT, with G-to-A or C-to-T transitions in KRAS or P53, although APC hypermethylation was associated with P53 mutation (P < 0.0002). CIMP with MSI-H due to hMLH1 hypermethylation, or CIMP with loss of MGMT expression in non-MSI-H tumors, was associated with BRAF mutation (OR, 4.5; P < 0.0002). CIMP was also associated with BRAF V600E T-to-A transversion (OR, 48.5; P < 0.0002). CONCLUSIONS Our findings suggest that the heterogeneous epigenetic dysregulation of promoter methylation in various genes is interrelated with the occurrence of mutations, as manifested in epigenetic-genetic subgroups of tumors.
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Affiliation(s)
- Yutaka Suehiro
- Department of Pathology, Division of Pathology and Laboratory Medicine, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
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Allgayer H, Owen RW, Nair J, Spiegelhalder B, Streit J, Reichel C, Bartsch H, Streit J, Reichel C, Bartsch H. Short-term moderate exercise programs reduce oxidative DNA damage as determined by high-performance liquid chromatography-electrospray ionization-mass spectrometry in patients with colorectal carcinoma following primary treatment. Scand J Gastroenterol 2008; 43:971-8. [PMID: 18609189 DOI: 10.1080/00365520701766111] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Oxidative DNA damage is believed to be involved in tumor formation and may be an important biomarker for malignant transition or relapse. A decrease of such damage has been observed in human and animal studies following dietary intervention and/or changes in lifestyle such as physical exercise at different levels of intensity. The purpose of this study was to carry out a clinical trial comparing the effects of a short-term (2 weeks) exercise program of moderate intensity (0.3-0.4 x maximal exercise capacity) (MI) versus high intensity (0.5-0.6 x maximal exercise capacity) (HI) on individual urinary excretion of 8-oxo-dG before and after completion of the exercise programs. MATERIAL AND METHODS In this short-term, prospective and randomized trial, 19 patients with colorectal cancer were allocated to the MI group following primary therapy and 29 to the HI group. Urinary 8-oxo-dG excretion concentration was determined by a highly sensitive detection method using high-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC-ESI-MS). Concentrations were determined immediately before and after completion of the exercise programs. RESULTS Using HPLC-ESI-MS, it was shown that MI exercise significantly reduced urinary 8-oxo-dG excretion levels from 8.47 +/- 1.99 to 5.81 +/- 1.45 (ng/mg creatinine, mean +/- SE, p = 0.02), whereas HI exercise resulted in a non-significant increase from 5.00 +/- 1.31 to 7.11 +/- 1.63 (ng/mg creatinine, p = 0.18). Clinical characteristics (gender, age, body mass index (BMI), diet, chemotherapy/irradiation) were not associated/correlated with urinary 8-oxo-dG levels. CONCLUSIONS By using HPLC-ESI-MS it was shown that short-term MI exercise after primary therapy in patients with colorectal cancer was associated with lower levels of urinary 8-oxo-dG, suggesting decreased oxidative DNA damage. In contrast, HI exercise tended to increase DNA damage. A prospective trial is now warranted to prove that reduced oxidative DNA damage lowers the risk of relapse of colorectal cancer in treated patients.
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Affiliation(s)
- Hubert Allgayer
- Oncology Department, Reha-klinik Ob der Tauber, Academic Teaching Hospital, University of Heidelberg, Bad Mergentheim, Germany.
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Cross AJ, Leitzmann MF, Gail MH, Hollenbeck AR, Schatzkin A, Sinha R. A prospective study of red and processed meat intake in relation to cancer risk. PLoS Med 2007; 4:e325. [PMID: 18076279 PMCID: PMC2121107 DOI: 10.1371/journal.pmed.0040325] [Citation(s) in RCA: 319] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 10/01/2001] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Red meat and processed meat have been associated with carcinogenesis at several anatomic sites, but no prospective study has examined meat intake in relation to a range of malignancies. We investigated whether red or processed meat intake increases cancer risk at a variety of sites. METHODS AND FINDINGS The National Institutes of Health (NIH)-AARP (formerly the American Association for Retired Persons) Diet and Health Study is a cohort of approximately 500,000 people aged 50-71 y at baseline (1995-1996). Meat intake was estimated from a food frequency questionnaire administered at baseline. Cox proportional hazards regression was used to estimate hazard ratios and 95% confidence intervals within quintiles of red and processed meat intake. During up to 8.2 y of follow-up, 53,396 incident cancers were ascertained. Statistically significant elevated risks (ranging from 20% to 60%) were evident for esophageal, colorectal, liver, and lung cancer, comparing individuals in the highest with those in the lowest quintile of red meat intake. Furthermore, individuals in the highest quintile of processed meat intake had a 20% elevated risk for colorectal and a 16% elevated risk for lung cancer. CONCLUSIONS Both red and processed meat intakes were positively associated with cancers of the colorectum and lung; furthermore, red meat intake was associated with an elevated risk for cancers of the esophagus and liver.
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Affiliation(s)
- Amanda J Cross
- Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Rockville, Maryland, United States of America.
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Lees NP, Harrison KL, Hall CN, Margison GP, Povey AC. Human colorectal mucosal O6-alkylguanine DNA-alkyltransferase activity and DNA-N7-methylguanine levels in colorectal adenoma cases and matched referents. Gut 2007; 56:380-4. [PMID: 16891355 PMCID: PMC1856833 DOI: 10.1136/gut.2006.097899] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
BACKGROUND AND AIMS O(6)-alkylguanine DNA-alkyltransferase (MGMT) provides protection against alkylating agent-induced GC-->AT transition mutations. Such mutations are frequently seen in the KRAS oncogene of large colorectal adenomas, but whether adenoma or mutational risk in humans is influenced by MGMT activity and alkylating agent exposure is unclear. Hence, MGMT activity and, as an indicator of alkylating agent exposure, DNA-N7-methylguanine (N7-MeG) levels were determined in the normal tissue of patients with and without adenomas. METHODS Biopsy specimens of normal colorectal mucosa were collected during colonoscopy from 85 patients with histologically proved colorectal adenomas (cases) and from 85 patients free of gastrointestinal neoplasia (referents) matched by age, sex and biopsy location. MGMT activity and N7-MeG levels were measured in colorectal tissue extracts and DNA, respectively. RESULTS MGMT activity was higher in the normal mucosa of cases than in referents (6.65+/-3.03 vs 5.61+/-2.74 fmol/micro g DNA, p = 0.01). On stratification of cases, MGMT activity was found to be considerably greater in the normal mucosa of cases with large adenomas (p = 0.003) and slightly higher in cases with a GC-->AT transition mutation in the K-ras gene (p = 0.03). Elevated MGMT levels were associated with an increased risk of adenoma (OR 1.17, 95% CI 1.03 to 1.33 per unit increase in activity). Detectable levels of N7-MeG were found in DNA from 89% of cases and 93% of referents, with levels ranging from <0.1 to 7.7 micro mol/mol dG. Cases and referents had similar DNA-N7-MeG levels. CONCLUSIONS Human exposure to methylating agents is widespread. MGMT activity is increased in the normal mucosa of patients with adenomas.
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Affiliation(s)
- N P Lees
- Cancer Research UK Carcinogenesis Group, Paterson Institute for Cancer Research, Christie Hospital, Manchester, UK
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Ganesan N, Kato S, Bowman ED, Shields PG. N-7-Alkyl-2'-Deoxyguanosine as surrogate biomarkers for N-nitrosamine exposure in human lung. INTERNATIONAL JOURNAL OF CANCER PREVENTION 2007; 2:265-277. [PMID: 19060962 PMCID: PMC2593895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
N-Nitrosamines are a large group of chemical compounds that are carcinogenic in animals, and probably in humans. These compounds form DNA adducts, namely 7-methyl-deoxyguanosine monophosphate (7-methyl-dGp) and 7-ethyl-deoxyguanosine monophosphate (7-ethyl-dGp). In study, we have used a combined two-step HPLC and (32)P-postlabeling assay to measure these adducts in the lung tissues of 88 autopsy donors. The mean levels for 7-methyl-dGp and 7-ethyl-dGp were 2.1 ± 0.9 (range 0.4 - 5.3) and 0.9 ± 0.5 (range = 0.1-3.0) adducts per 10(7) dGp. Normal distributions of adduct levels were found. The mean ratio for 7-methyl-dGp to 7-ethyl-dGp was 2.8 (S.D. = 2.3), and the levels were highly correlated (R=0.22, P=0.048). However, this was mostly attributed to nonsmokers. Examinations of adduct levels by race revealed no association with either of adducts studied (P=0.3 and P=0.7 for 7-methyl-dGp and 7-ethyl-dGp, respectively), serum cotinine (P=0.4) or ethanol (P=0.7). Overall, there was no association with smoking status, although there was a borderline correlation of the 7-ethyl-dGp adducts (P=0.09) among men, and for 7-methyl-2'-deoxyguanosine (P=0.03) among women. Women smokers showed higher 7-ethyl-dGp levels than men (P=0.03), and African American smokers had more 7-methyl-dGp levels that Caucasians (P=0.08). This study demonstrates that 7-ethyl-dGp adducts are lower than 7-methyl-dgP adducts in both smokers and non-smokers, but that they were only correlated in nonsmokers. Thus, there is a wide interindividual variation in adduct levels, likely due to differences in N-nitrosamine metabolism, which widens at higher levels of exposure. The presence of lower 7-ethyl-dGp levels in human tissues is consistent with experimental animal studies, yet ethylating N-nitrosamines are more potent than those that cause methylation. Although this study is limited by a small number of study subjects, the findings of higher adduct levels in women and African-American smokers are consistent with the reported increased risk and/or incidence of lung cancer in these groups.
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Affiliation(s)
- Natarajan Ganesan
- Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC-20057
| | | | - Elise D. Bowman
- Center for Cancer Research, National Cancer Institute, N.I.H., Bethesda, MD 20892
| | - Peter G. Shields
- Georgetown University Medical Center, Lombardi Comprehensive Cancer Center, Washington, DC-20057
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Larsson SC, Wolk A. Meat consumption and risk of colorectal cancer: a meta-analysis of prospective studies. Int J Cancer 2006; 119:2657-64. [PMID: 16991129 DOI: 10.1002/ijc.22170] [Citation(s) in RCA: 426] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Accumulating epidemiologic evidence indicates that high consumption of red meat and of processed meat may increase the risk of colorectal cancer. We quantitatively assessed the association between red meat and processed meat consumption and the risk of colorectal cancer in a meta-analysis of prospective studies published through March 2006. Random-effects models were used to pool study results and to assess dose-response relationships. We identified 15 prospective studies on red meat (involving 7,367 cases) and 14 prospective studies on processed meat consumption (7,903 cases). The summary relative risks (RRs) of colorectal cancer for the highest vs. the lowest intake categories were 1.28 (95% confidence interval (CI) = 1.15-1.42) for red meat and 1.20 (95% CI = 1.11-1.31) for processed meat. The estimated summary RRs were 1.28 (95% CI = 1.18-1.39) for an increase of 120 g/day of red meat and 1.09 (95% CI = 1.05-1.13) for an increase of 30 g/day of processed meat. Consumption of red meat and processed meat was positively associated with risk of both colon and rectal cancer, although the association with red meat appeared to be stronger for rectal cancer. In 3 studies that reported results for subsites in the colon, high consumption of processed meat was associated with an increased risk of distal colon cancer but not of proximal colon cancer. The results of this meta-analysis of prospective studies support the hypothesis that high consumption of red meat and of processed meat is associated with an increased risk of colorectal cancer.
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Affiliation(s)
- Susanna C Larsson
- Division of Nutritional Epidemiology, The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
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