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Luo D, Lu H, Wang C, Mubeen S, Cao S, Yue J, Pan J, Wu X, Wu Q, Zhang H, Chen C, Rehman M, Li R, Chen P. Physiological and DNA methylation analysis provides epigenetic insights into kenaf cadmium tolerance heterosis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 331:111663. [PMID: 36841339 DOI: 10.1016/j.plantsci.2023.111663] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 02/19/2023] [Accepted: 02/20/2023] [Indexed: 06/18/2023]
Abstract
Soil heavy metal pollution is one of the most challenging problems. Kenaf is an important natural fiber crop with strong heterosis and a higher tolerance to heavy metals. However, little is known about the molecular mechanisms of kenaf heavy metal tolerance, especially the mechanism of genomic DNA methylation regulating heterosis. In this study, kenaf cultivars CP085, CP089, and their hybrid F1 seedlings were subjected to 300 µM cadmium stress and found obvious heterosis of cadmium resistance in morphology and antioxidant enzyme activity of F1 hybrid seedlings. Through methylation-sensitive amplification polymorphism (MSAP) analysis, we highlighted that the total DNA methylation level under cadmium decreased by 16.9 % in F1 and increased by 14.0 % and 3.0 % in parents CP085 and CP089, respectively. The hypomethylation rate was highest (21.84 %), but hypermethylation was lowest (17.24 %) in F1 compared to parent cultivars. In particular, principal coordinates analysis (PCoA) indicates a significant epigenetic differentiation between F1 and its parents under cadmium. Furthermore, 21 differentially methylated DNA fragments (DMFs) were analyzed. Especially, the expression of NPF2.7, NADP-ME, NAC71, TPP-D, LRR-RLKs, and DHX51 genes were changed due to cadmium stress and related to cytosine methylation regulation. Finally, the knocked-down of the differentially methylated gene NPF2.7 by virus-induced gene silencing (VIGS) resulted in increased sensitivity of kenaf seedlings under cadmium stress. It is speculated that low DNA methylation levels can regulate gene expression that led to the heterosis of cadmium tolerance in kenaf.
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Affiliation(s)
- Dengjie Luo
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Hai Lu
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Caijin Wang
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Samavia Mubeen
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Shan Cao
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Jiao Yue
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Jiao Pan
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Xia Wu
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Qijing Wu
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Hui Zhang
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Canni Chen
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Muzammal Rehman
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Ru Li
- College of Life Science and Technology, Guangxi University, Nanning 530004, China
| | - Peng Chen
- Guangxi Key Laboratory of Agro-environment and Agric-products safety, Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning 530004, China.
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Hormesis and Oxidative Distress: Pathophysiology of Reactive Oxygen Species and the Open Question of Antioxidant Modulation and Supplementation. Antioxidants (Basel) 2022; 11:antiox11081613. [PMID: 36009331 PMCID: PMC9405171 DOI: 10.3390/antiox11081613] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/14/2022] [Accepted: 08/17/2022] [Indexed: 11/24/2022] Open
Abstract
Alterations of redox homeostasis leads to a condition of resilience known as hormesis that is due to the activation of redox-sensitive pathways stimulating cell proliferation, growth, differentiation, and angiogenesis. Instead, supraphysiological production of reactive oxygen species (ROS) exceeds antioxidant defence and leads to oxidative distress. This condition induces damage to biomolecules and is responsible or co-responsible for the onset of several chronic pathologies. Thus, a dietary antioxidant supplementation has been proposed in order to prevent aging, cardiovascular and degenerative diseases as well as carcinogenesis. However, this approach has failed to demonstrate efficacy, often leading to harmful side effects, in particular in patients affected by cancer. In this latter case, an approach based on endogenous antioxidant depletion, leading to ROS overproduction, has shown an interesting potential for enhancing susceptibility of patients to anticancer therapies. Therefore, a deep investigation of molecular pathways involved in redox balance is crucial in order to identify new molecular targets useful for the development of more effective therapeutic approaches. The review herein provides an overview of the pathophysiological role of ROS and focuses the attention on positive and negative aspects of antioxidant modulation with the intent to find new insights for a successful clinical application.
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Wu R, Li S, Hudlikar R, Wang L, Shannar A, Peter R, Chou PJ, Kuo HCD, Liu Z, Kong AN. Redox signaling, mitochondrial metabolism, epigenetics and redox active phytochemicals. Free Radic Biol Med 2022; 179:328-336. [PMID: 33359432 PMCID: PMC8222414 DOI: 10.1016/j.freeradbiomed.2020.12.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 11/29/2020] [Accepted: 12/14/2020] [Indexed: 02/03/2023]
Abstract
Biological redox signaling plays an important role in many diseases. Redox signaling involves reductive and oxidative mechanisms. Oxidative stress occurs when reductive mechanism underwhelms oxidative challenges. Cellular oxidative stress occurs when reactive oxygen/nitrogen species (RO/NS) exceed the cellular reductive/antioxidant capacity. Endogenously produced RO/NS from mitochondrial metabolic citric-acid-cycle coupled with electron-transport-chain or exogenous stimuli trigger cellular signaling events leading to homeostatic response or pathological damage. Recent evidence suggests that RO/NS also modulate epigenetic machinery driving gene expression. RO/NS affect DNA methylation/demethylation, histone acetylation/deacetylation or histone methylation/demethylation. Many health beneficial phytochemicals possess redox capability that counteract RO/NS either by directly scavenging the radicals or via inductive mechanism of cellular defense antioxidant/reductive enzymes. Amazingly, these phytochemicals also possess epigenetic modifying ability. This review summarizes the latest advances on the interactions between redox signaling, mitochondrial metabolism, epigenetics and redox active phytochemicals and the future challenges of integrating these events in human health.
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Affiliation(s)
- Renyi Wu
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Shanyi Li
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Rasika Hudlikar
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Lujing Wang
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Ahmad Shannar
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Rebecca Peter
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Pochung Jordan Chou
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Hsiao-Chen Dina Kuo
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Zhigang Liu
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Ah-Ng Kong
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA.
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Hudlikar R, Wang L, Wu R, Li S, Peter R, Shannar A, Chou PJ, Liu X, Liu Z, Kuo HCD, Kong AN. Epigenetics/Epigenomics and Prevention of Early Stages of Cancer by Isothiocyanates. Cancer Prev Res (Phila) 2020; 14:151-164. [PMID: 33055265 DOI: 10.1158/1940-6207.capr-20-0217] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/26/2020] [Accepted: 10/05/2020] [Indexed: 12/17/2022]
Abstract
Cancer is a complex disease and cancer development takes 10-50 years involving epigenetics. Evidence suggests that approximately 80% of human cancers are linked to environmental factors impinging upon genetics/epigenetics. Because advanced metastasized cancers are resistant to radiotherapy/chemotherapeutic drugs, cancer prevention by relatively nontoxic chemopreventive "epigenetic modifiers" involving epigenetics/epigenomics is logical. Isothiocyanates are relatively nontoxic at low nutritional and even higher pharmacologic doses, with good oral bioavailability, potent antioxidative stress/antiinflammatory activities, possess epigenetic-modifying properties, great anticancer efficacy in many in vitro cell culture and in vivo animal models. This review summarizes the latest advances on the role of epigenetics/epigenomics by isothiocyanates in prevention of skin, colon, lung, breast, and prostate cancers. The exact molecular mechanism how isothiocyanates modify the epigenetic/epigenomic machinery is unclear. We postulate "redox" processes would play important roles. In addition, isothiocyanates sulforaphane and phenethyl isothiocyanate, possess multifaceted molecular mechanisms would be considered as "general" cancer preventive agents not unlike chemotherapeutic agents like platinum-based or taxane-based drugs. Analogous to chemotherapeutic agents, the isothiocyanates would need to be used in combination with other nontoxic chemopreventive phytochemicals or drugs such as NSAIDs, 5-α-reductase/aromatase inhibitors targeting different signaling pathways would be logical for the prevention of progression of tumors to late advanced metastatic states.
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Affiliation(s)
- Rasika Hudlikar
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Lujing Wang
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey.,Graduate Program in Pharmaceutical Science, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Renyi Wu
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Shanyi Li
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Rebecca Peter
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey.,Graduate Program in Pharmaceutical Science, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Ahmad Shannar
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey.,Graduate Program in Pharmaceutical Science, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Pochung Jordan Chou
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey.,Graduate Program in Pharmaceutical Science, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Xia Liu
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey.,Department of Pharmacology, School of Basic Medical Science, Lanzhou University, Lanzhou, China
| | - Zhigang Liu
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey.,Department of Food and Pharmaceutical Engineering, Guiyang University, Guiyang, China
| | - Hsiao-Chen Dina Kuo
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey.,Graduate Program in Pharmaceutical Science, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey
| | - Ah-Ng Kong
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey.
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Su H, Ma D, Shang H, Fan J, Zhu H. DNA methylation of the prkaca gene involved in osmoregulation in tilapia hybrids (Oreochromis mossambicus × Oreochromis hornorum). Gene 2020; 752:144791. [PMID: 32439378 DOI: 10.1016/j.gene.2020.144791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 05/10/2020] [Accepted: 05/15/2020] [Indexed: 01/16/2023]
Abstract
Prkaca consists of the catalytic subunit alpha protein kinase A (PKA), which is involved in many cellular processes. In this study, the cDNA and genomic sequences of prkaca in tilapia hybrids (Oreochromis mossambicus × Oreochromis hornorum) were cloned and analysed. The results showed the prkaca gene consists of 11 exons and 10 introns, and its protein contains 351 amino acid residues and is clustered with Oreochromis niloticus, Maylandia zebra and Haplochromis burtoni first in a phylogenetic tree. Amino acid alignment indicates that prkaca shares the highest identity (100%) to Oreochromis niloticus, Maylandia zebra and Haplochromis burtoni. Two CpG islands of prkaca were found by MethPrimer software, and 32 CG sites were found in the proximal promoter. The methylation level of prkaca in the hybrids (0.31%) was significantly lower than that of their parents (0.94% and 3.43%) in kidney tissue (P < 0.05). The gene expression levels and DNA methylation levels of prkaca in muscle and kidney tissues of the tilapia hybrids were detected by quantitative real-time PCR and bisulfite sequencing PCR and showed a negative correlation under saline-alkali stress. The results of this research demonstrated that DNA methylation levels and prkaca mRNA expression levels were inversely correlated under saline-alkali stress, implying that heterosis is likely accompanied by DNA methylation alterations. This research provides new clues for further investigations of DNA methylation and heterosis in hybrid fish.
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Affiliation(s)
- Huanhuan Su
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Dongmei Ma
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Huiwen Shang
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Jiajia Fan
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Huaping Zhu
- Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China.
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Khosravizadeh Z, Hassanzadeh G, Tavakkoly Bazzaz J, Alizadeh F, Totonchi M, Salehi E, Khodamoradi K, Khanehzad M, Hosseini SR, Abolhassani F. The effect of cryopreservation on DNA methylation patterns of the chromosome 15q11-q13 region in human spermatozoa. Cell Tissue Bank 2020; 21:433-445. [PMID: 32253620 DOI: 10.1007/s10561-020-09828-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 03/11/2020] [Indexed: 01/23/2023]
Abstract
Human sperm cryopreservation is a common technique which is used in assisted reproductive technologies. Despite the existence of evidence supporting the production of ROS and DNA fragmentation during sperm cryopreservation, there is little and equivocal information about the cryopreservation effects on methylation of imprinted genes and imprinting control regions. In this study, we have investigated the effects of cryopreservation on DNA methylation in promoter regions of SNURF-SNRPN and UBE3A imprinted genes, PWS-ICR and AS-ICR in the chromosome 15q11-q13 region. Semen samples from 10 healthy normozoospermic men were collected and each sample was divided into four equal aliquots: fresh, cryoprotectant, cryopreservation, and H2O2. We measured the ROS levels and DNA fragmentation using DCFH-DA and TUNEL assay respectively by flow cytometry. DNA methylation in promoter regions of SNURF-SNRPN and UBE3A imprinted genes, PWS-ICR and AS-ICR in the chromosome 15q11-q13 region were evaluated by quantitative methylation-specific PCR technique. Intracellular levels of ROS and percentage of TUNEL-positive spermatozoa significantly increased in cryopreservation group compared to fresh group. Exposure to cryoprotectant had no significant effect on ROS levels and DNA fragmentation. Neither cryopreservation nor exposure to cryoprotectant significantly affected DNA methylation of the selected gene regions. However, DNA fragmentation had positive correlation with DNA methylation of AS-ICR. In conclusion, based on our study, clinical use of sperm cryopreservation for fertility treatments appear to be safe in regard to DNA methylation in the chromosome 15q11-q13 region.
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Affiliation(s)
- Zahra Khosravizadeh
- Faculty of Anatomy, School of Medicine, Tehran University of Medical Science, 16 Azar Avenue, Poor Sina Street, Tehran, Iran
| | - Gholamreza Hassanzadeh
- Faculty of Anatomy, School of Medicine, Tehran University of Medical Science, 16 Azar Avenue, Poor Sina Street, Tehran, Iran
| | - Javad Tavakkoly Bazzaz
- Faculty of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, 16 Azar Avenue, Poor Sina Street, Tehran, Iran
| | - Fatemeh Alizadeh
- Faculty of Genomic Psychiatry and Behavioral Genomics (DGPBG), Roozbeh Hospital, School of Medicine, Tehran University of Medical Science, South Kargar Avenue, Tehran, Iran
| | - Mehdi Totonchi
- Faculty of Stem Cells and Developmental Biology, Royan Institute, Tehran, Iran
| | - Ensieh Salehi
- Faculty of Gynecology, School of Medicine, Fertility and Infertility Research Center, Bandar Abbas, Iran.,Dr. Ali Shariati Hospital, Shahid Mohammadi Hospital, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Kajal Khodamoradi
- Faculty of Anatomy, School of Medicine, Tehran University of Medical Science, 16 Azar Avenue, Poor Sina Street, Tehran, Iran
| | - Maryam Khanehzad
- Faculty of Anatomy, School of Medicine, Tehran University of Medical Science, 16 Azar Avenue, Poor Sina Street, Tehran, Iran
| | - Seyed Reza Hosseini
- Faculty of Urology, Sina Hospital, Tehran University of Medical Science, Imam Khomeini Street, Tehran, Iran.
| | - Farid Abolhassani
- Faculty of Anatomy, School of Medicine, Tehran University of Medical Science, 16 Azar Avenue, Poor Sina Street, Tehran, Iran.
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Barati E, Nikzad H, Karimian M. Oxidative stress and male infertility: current knowledge of pathophysiology and role of antioxidant therapy in disease management. Cell Mol Life Sci 2020; 77:93-113. [PMID: 31377843 PMCID: PMC11105059 DOI: 10.1007/s00018-019-03253-8] [Citation(s) in RCA: 225] [Impact Index Per Article: 56.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 07/11/2019] [Accepted: 07/24/2019] [Indexed: 12/11/2022]
Abstract
Infertility is a global health problem involving about 15% of couples. Approximately half of the infertility cases are related to male factors. The oxidative stress, which refers to an imbalance in levels of reactive oxygen species (ROS) and antioxidants, is one of the main causes of infertility in men. A small amount of ROS is necessary for the physiological function of sperm including the capacitation, hyperactivation and acrosomal reaction. However, high levels of ROS can cause infertility through not only by lipid peroxidation or DNA damage but inactivation of enzymes and oxidation of proteins in spermatozoa. Oxidative stress (OS) is mainly caused by factors associated with lifestyle. Besides, immature spermatozoa, inflammatory factors, genetic mutations and altering levels of sex hormones are other main source of ROS. Since OS occurs due to the lack of antioxidants and its side effects in semen, lifestyle changes and antioxidant regimens can be helpful therapeutic approaches to overcome this problem. The present study aimed to describe physiological ROS production, roles of genetic and epigenetic factors on the OS and male infertility with various mechanisms such as lipid peroxidation, DNA damage, and disorder of male hormone profile, inflammation, and varicocele. Finally, the roles of oral antioxidants and herbs were explained in coping with OS in male infertility.
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Affiliation(s)
- Erfaneh Barati
- Anatomical Sciences Research Center, Kashan University of Medical Sciences, Kashan, Iran
| | - Hossein Nikzad
- Anatomical Sciences Research Center, Kashan University of Medical Sciences, Kashan, Iran
- Gametogenesis Research Center, Kashan University of Medical Sciences, Kashan, Iran
| | - Mohammad Karimian
- Anatomical Sciences Research Center, Kashan University of Medical Sciences, Kashan, Iran.
- Gametogenesis Research Center, Kashan University of Medical Sciences, Kashan, Iran.
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Urban L, Charles F, de Miranda MRA, Aarrouf J. Understanding the physiological effects of UV-C light and exploiting its agronomic potential before and after harvest. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 105:1-11. [PMID: 27064192 DOI: 10.1016/j.plaphy.2016.04.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 03/30/2016] [Accepted: 04/03/2016] [Indexed: 05/01/2023]
Abstract
There is an abundant literature about the biological and physiological effects of UV-B light and the signaling and metabolic pathways it triggers and influences. Much less is known about UV-C light even though it seems to have a lot of potential for being effective in less time than UV-B light. UV-C light is known since long to exert direct and indirect inhibitory and damaging effects on living cells and is therefore commonly used for disinfection purposes. More recent observations suggest that UV-C light can also be exploited to stimulate the production of health-promoting phytochemicals, to extent shelf life of fruits and vegetables and to stimulate mechanisms of adaptation to biotic and abiotic stresses. Clearly some of these effects may be related to the stimulating effect of UV-C light on the production of reactive oxygen species (ROS) and to the stimulation of antioxidant molecules and mechanisms, although UV-C light could also trigger and regulate signaling pathways independently from its effect on the production of ROS. Our review clearly underlines the high potential of UV-C light in agriculture and therefore advocates for more work to be done to improve its efficiency and also to increase our understanding of the way UV-C light is perceived and influences the physiology of plants.
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Affiliation(s)
- Laurent Urban
- Unité Mixte de Recherche Qualisud, Laboratoire de Physiologie des Fruits et Légumes, Université d'Avignon et des Pays de Vaucluse, 301 rue Baruch de Spinoza, BP 2139 - 84916, Avignon cedex 9, France.
| | - Florence Charles
- Unité Mixte de Recherche Qualisud, Laboratoire de Physiologie des Fruits et Légumes, Université d'Avignon et des Pays de Vaucluse, 301 rue Baruch de Spinoza, BP 2139 - 84916, Avignon cedex 9, France
| | - Maria Raquel Alcântara de Miranda
- Laboratório de Fisiologia e Bioquímica de Frutos, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Ceará, Av. Mr. Hull 2297 Bl. 907, Campus do Pici, CEP 60455-760, Fortaleza, CE, Brazil
| | - Jawad Aarrouf
- Unité Mixte de Recherche Qualisud, Laboratoire de Physiologie des Fruits et Légumes, Université d'Avignon et des Pays de Vaucluse, 301 rue Baruch de Spinoza, BP 2139 - 84916, Avignon cedex 9, France
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9
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Rahman MB, Kamal MM, Rijsselaere T, Vandaele L, Shamsuddin M, Van Soom A. Altered chromatin condensation of heat-stressed spermatozoa perturbs the dynamics of DNA methylation reprogramming in the paternal genome after in vitro fertilisation in cattle. Reprod Fertil Dev 2015; 26:1107-16. [PMID: 24041366 DOI: 10.1071/rd13218] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 08/07/2013] [Indexed: 12/15/2022] Open
Abstract
Shortly after penetration of the oocyte, sperm DNA is actively demethylated, which is required for totipotent zygotic development. Aberrant DNA methylation is thought to be associated with altered chromatin condensation of spermatozoa. The objectives of this study were to investigate the dynamics of DNA methylation reprogramming in the paternal pronucleus and subsequent fertilisation potential of heat-stressed bull spermatozoa having altered chromatin condensation. Hence, bovine zygotes (n=1239) were collected at three different time points (12, 18 and 24h post insemination, hpi), and stained with an antibody against 5-methylcytosine. Fluorescence intensities of paternal and maternal pronuclei were measured by ImageJ. DNA methylation patterns in paternal pronuclei derived from heat-stressed spermatozoa did not differ between time points (P>0.05), whereas control zygotes clearly showed demethylation and de novo methylation at 18 and 24hpi, respectively. Moreover, heat-stressed spermatozoa showed a highly reduced (P<0.01) fertilisation rate compared with non-heat-stressed or normal control spermatozoa (53.7% vs 70.2% or 81.5%, respectively). Our data show that the normal pattern of active DNA demethylation followed by de novo methylation in the paternal pronucleus is perturbed when oocytes are fertilised with heat-stressed spermatozoa, which may be responsible for decreased fertilisation potential.
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Affiliation(s)
- Mohammad Bozlur Rahman
- Department of Reproduction, Obstetrics and Herd Health, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Md Mostofa Kamal
- Department of Reproduction, Obstetrics and Herd Health, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Tom Rijsselaere
- Department of Reproduction, Obstetrics and Herd Health, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
| | - Leen Vandaele
- Department of Animal Science, Institute for Agricultural and Fisheries Research, Scheldeweg 68, 9090 Melle, Belgium
| | - Mohammed Shamsuddin
- Department of Surgery and Obstetrics, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
| | - Ann Van Soom
- Department of Reproduction, Obstetrics and Herd Health, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium
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So MY, Tian Z, Phoon YS, Sha S, Antoniou MN, Zhang J, Wu RSS, Tan-Un KC. Gene expression profile and toxic effects in human bronchial epithelial cells exposed to zearalenone. PLoS One 2014; 9:e96404. [PMID: 24788721 PMCID: PMC4008614 DOI: 10.1371/journal.pone.0096404] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 04/05/2014] [Indexed: 01/24/2023] Open
Abstract
Zearalenone (ZEA), a mycoestrogen produced by Fusarium fungal species, is mainly found in cereal crops such as maize, wheat and barley. Although ZEA has been reported to be present in air, little is known about the health risk or the molecular basis of action when lung cells are exposed to ZEA. As ZEA has a similar structure to estrogen, its potential risk as an endocrine disrupting chemical (EDC) has thus aroused both environmental and public health concerns. The purpose of this study is to identify the responses and underlying molecular changes that occur when human bronchial epithelial BEAS-2B cells are exposed to ZEA. Differential gene expression profiles were identified in cells that were treated with 40 µM ZEA for 6 h and 24 h by high-throughput microarray analysis using Affymetrix Human Gene 2.0 GeneChip. The array results showed that after ZEA treatment, 262 genes at 6 h and 1073 genes at 24 h were invovled in the differential regulation. Pathway analysis revealed that diverse cellular processes were affected when lung cells were exposed to ZEA resulting in impaired response to DNA damage, cell cycle arrest, down-regulation of inflammatory responses and alterations of epigenetic marks. Results of further experiments indicated that 40 µM ZEA decreased cell viability, induced apoptosis and promoted reactive oxygen species (ROS) generation in a time-dependent manner. Immuno-suppressive effects of ZEA were further revealed through the suppression of lipopolysaccharide (LPS)-induced expression of pro-inflammatory cytokines (IL-6, IL-8 and IL-1β). Interestingly, the level of global DNA methylation was markedly decreased after 24 h exposure to ZEA. Collectively, these observations suggested that a broad range of toxic effects are elicited by ZEA. Particularly, ROS may play a pivotal role in ZEA-induced cell death. These adverse effects observed in lung cells suggest that exposure to ZEA may increase susceptibility of lung cells to diseases and required further investigations.
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Affiliation(s)
- Mei Yu So
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - ZhiPeng Tian
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
- School of Professional and Continuing Education, The University of Hong Kong, Hong Kong SAR, China
| | - Yong Shian Phoon
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Sha Sha
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Michael N. Antoniou
- Department of Medical and Molecular Genetics, Gene Expression and Therapy Group, King's College London School of Medicine, Guy's Hospital, London, United Kingdom
| | - JiangWen Zhang
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Rudolf S. S. Wu
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Kian C Tan-Un
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
- School of Professional and Continuing Education, The University of Hong Kong, Hong Kong SAR, China
- * E-mail: address:
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11
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Maeda T, Guan JZ, Koyanagi M, Higuchi Y, Makino N. Aging-associated alteration of telomere length and subtelomeric status in female patients with Parkinson's disease. J Neurogenet 2012; 26:245-51. [PMID: 22364520 DOI: 10.3109/01677063.2011.651665] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A telomere is a repetitive DNA structure at chromosomal ends that stabilizes the chromosome structure and prevents harmful end-to-end recombinations. The telomere length of somatic cells becomes shorter with aging because of the "end replication problem." This telomere shortening is accelerated by pathophysiological conditions including daily mental stress. Living with Parkinson's disease (PD) causes physical and mental stress; therefore, the authors hypothesized that the telomere length of somatic cells was shortened excessively in patients with PD. In order to detect PD-associated somatic telomeric alterations, the telomere length and subtelomeric methylation status of peripheral leukocytes of PD patients were assessed by Southern blotting, using methylation-sensitive and -insensitive isoschizomers. The results demonstrated that the peripheral leukocytes of Japanese female patients with PD bore fewer long telomeres and a proportional increase of hypomethylated subtelomeres in short telomeres in comparison with the healthy controls. This study indicates that with the neurodegeneration associated with PD, telomeric and subtelomeric structural alterations occur. These structural telomere alterations most likely occur secondary to the acceleration of aging-associated telomeric changes and the accelerated loss of cells bearing short telomeres.
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Affiliation(s)
- Toyoki Maeda
- Department of Cardiovascular, Respiratory and Geriatric Medicine, Kyushu University Beppu Hospital, 4546 Tsurumihara, Beppu, Oita, Japan.
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12
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Time-series analysis of gene expression profiles induced by nitrosamides and nitrosamines elucidates modes of action underlying their genotoxicity in human colon cells. Toxicol Lett 2011; 207:232-41. [DOI: 10.1016/j.toxlet.2011.09.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 09/13/2011] [Accepted: 09/14/2011] [Indexed: 01/21/2023]
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13
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N-nitroso compound exposure-associated transcriptomic profiles are indicative of an increased risk for colorectal cancer. Cancer Lett 2011; 309:1-10. [PMID: 21669488 DOI: 10.1016/j.canlet.2011.05.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 05/11/2011] [Accepted: 05/12/2011] [Indexed: 01/31/2023]
Abstract
Endogenous formation of N-nitroso compounds (NOCs), which are known animal carcinogens, could contribute to human carcinogenesis but definitive evidence is still lacking. To investigate the relevance of NOCs in human colorectal cancer (CRC) development, we analyzed whole genome gene expression modifications in human colon biopsies in relation to fecal NOC exposure. We had a particular interest in patients suffering from intestinal inflammation as this may stimulate endogenous NOC formation, and consequently predispose to CRC risk. Inflammatory bowel disease (IBD) patients diagnosed with ulcerative colitis and irritable bowel syndrome patients without inflammation, serving as controls, were therefore recruited. Fecal NOC were demonstrated in the majority of subjects. By associating gene expression levels of all subjects to fecal NOC levels, we identified a NOC exposure-associated transcriptomic response that suggests that physiological NOC concentrations may potentially induce genotoxic responses and chromatin modifications in human colon tissue, both of which are linked to carcinogenicity. In a network analysis, chromatin modifications were linked to 11 significantly modulated histone genes, pointing towards a possible epigenetic mechanism that may be relevant in comprehending NOC-induced carcinogenesis. In addition, pro-inflammatory transcriptomic modifications were identified in visually non-inflamed regions of the IBD colon. However, fecal NOC levels were slightly but not significantly increased in IBD patients, suggesting that inflammation did not strongly stimulate NOC formation. We conclude that NOC exposure is associated with gene expression modifications in the human colon that may suggest a potential role of these compounds in CRC development.
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14
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Minor A, Chow V, Ma S. Aberrant DNA methylation at imprinted genes in testicular sperm retrieved from men with obstructive azoospermia and undergoing vasectomy reversal. Reproduction 2011; 141:749-57. [DOI: 10.1530/rep-11-0008] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Male factor infertility has been associated with abnormal DNA methylation at imprinted genes. Little information is available on the status of imprinting in the sperm of men with azoospermia, including the association between aberrant imprinting and obstructive azoospermia (OA) or non-OA (NOA). Analysis of DNA methylation at imprinted genes in the sperm of men undergoing vasectomy reversal would aid determination of whether aberrant imprinting is associated with obstruction. Testicular sperm was retrieved from testicular biopsies obtained from men with azoospermia (N=18), including OA (N=10), NOA (N=5), and unknown pathology (N=3), and from men undergoing vasectomy reversal (N=17). Sperm was also obtained from proven fertile men (N=9). DNA methylation was investigated at multiple CpG sites within the differentially methylated regions (DMRs) of three imprinted genes,H19,IG-GTL2andMEST, using bisulphite sequencing. Unique clones representative of single cells were analyzed. We found a significant decrease in DNA methylation at theH19DMR in testicular sperm of azoospermic men compared with proven fertile men. The decrease was also significant between OA and proven fertile men, and between men undergoing vasectomy reversal and proven fertile men, suggesting that aberrant DNA methylation may be associated with obstruction. Changes in DNA methylation atIG-GTL2andMESTDMRs among groups were not significant. Our data suggest that imprinting abnormalities may be associated with obstruction and may occur in response to changes in testicular environment and not only spermatogenesis failure, as previously reported. Methylation at theH19DMR was particularly prone to modification in testicular sperm.
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15
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Ziech D, Franco R, Pappa A, Panayiotidis MI. Reactive oxygen species (ROS)--induced genetic and epigenetic alterations in human carcinogenesis. Mutat Res 2011; 711:167-73. [PMID: 21419141 DOI: 10.1016/j.mrfmmm.2011.02.015] [Citation(s) in RCA: 369] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 02/26/2011] [Accepted: 02/28/2011] [Indexed: 12/12/2022]
Abstract
Cancer is a multistage and complex process characterized by molecular alterations that underlie all three phases of its development: (i) initiation, (ii) promotion and (iii) progression. Some of these molecular events include alterations in gene expression that are regulated by both genetic and epigenetic mechanisms. On the other hand, "oxidative stress" implies a cellular state where ROS production exceeds the cell's ability to metabolize them resulting in excessive accumulation of ROS that overwhelms cellular defenses. Such state has been shown to regulate both genetic and epigenetic cascades underlying altered gene expression in human disease including cancer. Throughout this manuscript, we review the current state of knowledge on the role of ROS-induced oxidative stress in altering the genetic and epigenetic involvement during human carcinogenesis.
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Affiliation(s)
- Dominique Ziech
- Department of Student Success Services, University of Nevada, Reno, NV 89557, USA
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16
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Maltseva DV, Gromova ES. Interaction of murine Dnmt3a with DNA containing O6-methylguanine. BIOCHEMISTRY (MOSCOW) 2010; 75:173-81. [DOI: 10.1134/s0006297910020070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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17
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Tunc O, Tremellen K. Oxidative DNA damage impairs global sperm DNA methylation in infertile men. J Assist Reprod Genet 2009; 26:537-44. [PMID: 19876730 DOI: 10.1007/s10815-009-9346-2] [Citation(s) in RCA: 173] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 09/16/2009] [Indexed: 01/07/2023] Open
Abstract
PURPOSE Methylation of sperm DNA is impaired in many infertile men potentially adversely effecting reproductive outcomes. In somatic cells oxidative damage to DNA and hyperhomocysteinaemia are linked with DNA hypomethylation. The objective of this study was to investigate if these pathologies also impair sperm DNA methylation. METHODS The relationship between sperm DNA quality, oxidative stress and serum homocysteine was analysed at study entry and after 3 months of antioxidant treatment. RESULTS Overall a significant negative correlation was observed between sperm DNA methylation and sperm DNA fragmentation, as well as seminal reactive oxygen species (ROS) production. Sperm DNA methylation was not significantly related to serum homocysteine concentrations. Administration of an antioxidant supplement produced a significant fall in seminal ROS levels and sperm DNA fragmentation, while increasing sperm DNA methylation. CONCLUSIONS These results suggest that oxidative stress related damage to sperm DNA impedes the process of methylation, while antioxidant supplementation appears to have the potential to reduce DNA damage and normalize sperm DNA methylation.
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Affiliation(s)
- Ozlem Tunc
- Research Centre for Reproductive Health, Discipline of Obstetrics and Gynaecology, School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, South Australia
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18
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Maeda T, Guan JZ, Oyama JI, Higuchi Y, Makino N. Aging-associated alteration of subtelomeric methylation in Parkinson's disease. J Gerontol A Biol Sci Med Sci 2009; 64:949-55. [PMID: 19502593 DOI: 10.1093/gerona/glp070] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A telomere is a repetitive DNA structure capping the chromosomal ends. Telomeres stabilize the chromosome structure and prevent harmful end-to-end recombinations. The telomere length of somatic cells can be determined as the terminal restriction fragment length provided by a genomic Southern blotting analysis, and the telomere length becomes shorter at each mitotic cycle due to an "end-replication problem." Therefore, older somatic cells, which have undergone more mitotic cycles, bear shorter telomeres. This telomere shortening is accelerated by various disease conditions. Parkinson's disease (PD) also yields telomere fragility, thus accelerating the telomere shortening of the circulating leukocytes. This study found that peripheral leukocytes of Japanese PD patients bear fewer short telomeres with constant subtelomeric methylation status in comparison with the healthy controls with increasing short telomeres and also increasing hypomethylated subtelomeres in short telomeres with aging. The correlation between the telomeric attrition and the subtelomeric methylated state in PD is herein discussed.
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Affiliation(s)
- Toyoki Maeda
- Department of Molecular and Cellular Biology, Division of Molecular and Clinical Gerontology, Medical Institute of Bioregulation, Kyushu University, 4546 Tsurumihara, Beppu, Oita 874-0838, Japan.
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19
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LIANG QJ, LIU LN, PENG J, SUN ZD, JIANG SW. Determination and Difference Analysis of DNA Methylation Content Both in Blood and Muscle Tissue of Pigs. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/s1671-2927(08)60140-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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20
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Oxidative stress, DNA methylation and carcinogenesis. Cancer Lett 2008; 266:6-11. [PMID: 18372104 DOI: 10.1016/j.canlet.2008.02.026] [Citation(s) in RCA: 399] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Revised: 02/12/2008] [Accepted: 02/14/2008] [Indexed: 11/20/2022]
Abstract
Transformation of a normal cell to a malignant one requires phenotypic changes often associated with each of the initiation, promotion and progression phases of the carcinogenic process. Genes in each of these phases acquire alterations in their transcriptional activity that are associated either with hypermethylation-induced transcriptional repression (in the case of tumor suppressor genes) or hypomethylation-induced activation (in the case of oncogenes). Growing evidence supports a role of ROS-induced generation of oxidative stress in these epigenetic processes and as such we can hypothesize of potential mode(s) of action by which oxidative stress modulates epigenetic regulation of gene expression. This is of outmost importance given that various components of the epigenetic pathway and primarily aberrant DNA methylation patterns are used as potential biomarkers for cancer diagnosis and prognosis.
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21
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Kim YI. Folate and DNA Methylation: A Mechanistic Link between Folate Deficiency and Colorectal Cancer? Cancer Epidemiol Biomarkers Prev 2004. [DOI: 10.1158/1055-9965.511.13.4] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Abstract
Epidemiological, clinical, and animal studies collectively indicate that dietary folate intake and blood folate levels are inversely associated with colorectal cancer risk. Folate plays an essential role in one-carbon transfer involving remethylation of homocysteine to methionine, which is a precursor of S-adenosylmethionine, the primary methyl group donor for most biological methylations. DNA methylation is an important epigenetic determinant in gene expression, maintenance of DNA integrity and stability, chromosomal modifications, and development of mutations. Dysregulation and aberrant patterns of DNA methylation are generally considered to be mechanistically involved in colorectal carcinogenesis. Aberrant DNA methylation has been considered as a leading mechanism by which folate deficiency enhances colorectal carcinogenesis. However, currently available data pertaining to the effects of folate deficiency on DNA methylation are inconsistent and incomplete. The portfolio of evidence from animal, human, and in vitro studies suggests that the effects of folate deficiency on DNA methylation are highly complex; appear to depend on cell type, target organ, and stage of transformation; and are gene and site specific. In addition, the pattern of site- and gene-specific DNA methylation induced by folate deficiency may not be in concert with the direction of changes in genomic DNA methylation. Collectively, currently available evidence indicates that genomic DNA hypomethylation in the colorectum is not a probable mechanism by which folate deficiency enhances colorectal carcinogenesis. However, there is still a possibility that sequence-specific alterations of DNA methylation in critical cancer-related genes might be mechanistically involved in the folate deficiency-mediated colorectal carcinogenesis.
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Affiliation(s)
- Young-In Kim
- Departments of Medicine and Nutritional Sciences, University of Toronto, Toronto, ON, Canada and Division of Gastroenterology, St. Michael's Hospital, Toronto, ON, Canada
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22
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Esteller M, Herman JG. Generating mutations but providing chemosensitivity: the role of O6-methylguanine DNA methyltransferase in human cancer. Oncogene 2004; 23:1-8. [PMID: 14712205 DOI: 10.1038/sj.onc.1207316] [Citation(s) in RCA: 222] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
O(6)-methylguanine DNA methyltransferase (MGMT) is a key enzyme in the DNA repair network. MGMT removes mutagenic and cytotoxic adducts from O(6)-guanine in DNA, the preferred point of attack of many carcinogens (i.e. methylnitrosourea) and alkylating chemotherapeutic agents (i.e. BCNU, temozolamide, etc.). Hypermethylation of the CpG island located in the promoter region of MGMT is primarily responsible for the loss of MGMT function in many tumor types. The methylation-mediated silencing of MGMT has two consequences for cancer. First, tumors with MGMT methylation have a new mutator phenotype characterized by the generation of transition point mutations in genes involved in cancer etiology, such as the tumor suppressor p53 and the oncogene K-ras. Second, MGMT hypermethylation demonstrates the possibility of pharmacoepigenomics: methylated tumors are more sensitive to the killing effects of alkylating drugs used in chemotherapy. These recent results underscore the importance of MGMT in basic and translational cancer research.
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Affiliation(s)
- Manel Esteller
- Cancer Epigenetics Laboratory, Molecular Pathology Program, Spanish National Cancer Center (CNIO), Melchor Fernandez Almagro 3, Madrid 28029, Spain.
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23
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Kim YI. Folate, colorectal carcinogenesis, and DNA methylation: lessons from animal studies. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2004; 44:10-25. [PMID: 15199543 DOI: 10.1002/em.20025] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Folate, a water-soluble B vitamin and cofactor in one-carbon transfer, is an important nutritional factor that may modulate the development of colorectal cancer (CRC). Epidemiologic and clinical studies indicate that dietary folate intake and blood folate levels are inversely associated with CRC risk. Collectively, these studies suggest an approximately 40% reduction in the risk of CRC in individuals with the highest dietary folate intake compared with those with the lowest intake. Animal studies using chemical and genetically predisposed rodent models have provided considerable support for a causal relationship between folate depletion and colorectal carcinogenesis as well as a dose-dependent protective effect of folate supplementation. However, animal studies also have shown that the dose and timing of folate intervention are critical in providing safe and effective chemoprevention; exceptionally high supplemental folate levels and folate intervention after microscopic neoplastic foci are established in the colorectal mucosa promote, rather than suppress, colorectal carcinogenesis. These animal studies, in conjunction with clinical observations, suggest that folate possesses dual modulatory effects on carcinogenesis depending on the timing and dose of folate intervention. Folate deficiency has an inhibitory effect, whereas folate supplementation has a promoting effect on the progression of established neoplasms. In contrast, folate deficiency in normal epithelial tissues appears to predispose them to neoplastic transformation, and modest levels of folate supplementation suppress the development of tumors in normal tissues. Notwithstanding the limitations associated with animal models, these studies suggest that the optimal timing and dose of folate intervention must be established for safe and effective chemoprevention in humans. Folate is an important factor in DNA synthesis, stability, and integrity, the repair aberrations of which have been implicated in colorectal carcinogenesis. Folate may also modulate DNA methylation, which is an important epigenetic determinant in gene expression (an inverse relationship), in the maintenance of DNA integrity and stability, in chromosomal modifications, and in the development of mutations. A mechanistic understanding of how folate status modulates colorectal carcinogenesis further strengthens the case for a causal relationship and provides insight into a possible chemopreventive role of folate.
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Affiliation(s)
- Young-In Kim
- Departments of Medicine and Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada.
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24
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Yang Y, Nikolic D, Swanson SM, van Breemen RB. Quantitative determination of N7-methyldeoxyguanosine and O6-methyldeoxyguanosine in DNA by LC-UV-MS-MS. Anal Chem 2002; 74:5376-82. [PMID: 12403596 DOI: 10.1021/ac020235o] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The N-7 and O-6 positions of 2'-deoxyguanosine are the predominant sites of methylation by N-methyl-N-nitrosourea (MNU), which is used to produce a variety of experimental cancers in animal models. Here we report the development of a highly sensitive quantitative assay based on high-performance liquid chromatography-UV-tandem mass spectrometry (LC-UV-MS-MS) to measure N7-methyl-2'-deoxyguanosine (N7-MedG) and O6-methyl-2'-deoxyguanosine (O6-MedG) in DNA hydrolysates. Since this assay was selective for deoxyribonucleosides, potential interference from methylated RNA was eliminated. Isotopically labeled analogues, [2H3]N7-MedG and [2H3]O6-MedG, were synthesized and added to the DNA hydrolysates as internal standards. In-line UV absorbance detection was used for the quantitative analysis of the native deoxyribonucleoside dG, and MS-MS was used for the determination of N7-MedG and O6-MedG. The limits of detection for N7-MedG and O6-MedG were determined to be 64 and 43 fmol, respectively. The limits of quantification were 0.13 pmol for N7-MedG and 0.085 pmol for O6-MedG. The stabilities of N7-MedG and O6-MedG were also investigated. Although O6-MedG was stable at room temperature for at least 11 days, the half-life of N7-MedG at room temperature was 2 days. Both adducts were stable at -20 degrees C. Calf thymus DNA and DNA from the livers of MNU-treated Sprague-Dawley rats were assayed using LC-UV-MS-MS, which was optimized for speed as well as for sensitivity. The levels of N7-MedG and 06-MedG in calf thymus DNA increased with MNU concentration and incubation time. The levels of N7-MedG and O6-MedG in the rat livers 2 h after treatment with a single dose of 50 mg/kg MNU were 95.2 N7-MedG/105 dG and 14.8 O6-MedG/105 dG. This LC-UV-MS-MS assay provides the sensitivity and speed required to evaluate the extent of methylated DNA lesions in animal models of cancer induced by the methylating agent MNU.
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Affiliation(s)
- Yanan Yang
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, 60612, USA
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Abstract
This review focuses on the role that DNA methylation plays in the regulation of normal and aberrant gene expression and on how, in a hypothesis-driven fashion, altered DNA methylation may be viewed as a secondary mechanism involved in carcinogenesis. Research aimed at discerning the mechanisms by which chemicals can transform normal cells into frank carcinomas has both theoretical and practical implications. Through an increased understanding of the mechanisms by which chemicals affect the carcinogenic process, we learn more about basic biology while, at the same time, providing the type of information required to make more rational safety assessment decisions concerning their actual potential to cause cancer under particular conditions of exposure. One key question is: does the mechanism of action of the chemical in question involve a secondary mechanism and, if so, what dose may be below its threshold?
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Affiliation(s)
- Jay I Goodman
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824, USA.
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26
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Rusmintratip V, Sowers LC. An unexpectedly high excision capacity for mispaired 5-hydroxymethyluracil in human cell extracts. Proc Natl Acad Sci U S A 2000; 97:14183-7. [PMID: 11121024 PMCID: PMC18892 DOI: 10.1073/pnas.97.26.14183] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The oxidation of thymine in DNA can generate a base pair between 5-hydroxymethyluracil (HmU) and adenine, whereas the oxidation and deamination of 5-methylcytosine (5mC) in DNA can generate a base pair between HmU and guanine. Using synthetic oligonucleotides containing HmU at a defined site, HmU-DNA glycosylase activities in HeLa cell and human fibroblast cell extracts have been observed. An HmU-DNA glycosylase activity that removes HmU mispaired with guanine has been measured. Surprisingly, the HmU:G excision activity is 60 times greater than the corresponding HmU:A activity, even though the expected rate of formation of the HmU:A base pair exceeds that of the HmU:G base pair by a factor of 10(7). The HmU:G mispair would arise from the 5mC:G base pair, and, if unrepaired, would give rise to a transition mutation. The observation of an unexpectedly high HmU:G glycosylase activity suggests that human cells may encounter the HmU:G mispair much more frequently than expected. The conversion of 5mC to HmU must be considered as a potential pathway for the generation of 5mC to T transition mutations, which are often found in human tumors.
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Affiliation(s)
- V Rusmintratip
- Divisions of Pediatrics and Molecular Medicine, City of Hope National Medical Center, 1500 East Duarte Road, Duarte, CA 91010, USA
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27
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Goodman JI. Response to "Epigenetic mechanisms of carcinogenesis" by Klaunig JE, Kamendulis LM and Xu Y. Hum Exp Toxicol 2000; 19:563-5; discussion 571-2. [PMID: 11211994 DOI: 10.1191/096032700701546479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
It is now quite clear that carcinogenesis involves more than mutagenesis and an increased focus on epigenetic events underlying the transformation of a normal cell into a frank malignancy is appropriate.
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Affiliation(s)
- J I Goodman
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing 48824, USA
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Flynn J, Azzam R, Reich N. DNA binding discrimination of the murine DNA cytosine-C5 methyltransferase. J Mol Biol 1998; 279:101-16. [PMID: 9636703 DOI: 10.1006/jmbi.1998.1761] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mammalian DNA cytosine-C5 methyltransferase modifies the CpG dinucleotide in the context of many different genomic sequences. A rigorous DNA binding assay was developed for the murine enzyme and used to define how sequences flanking the CpG dinucleotide affect the stability of the enzyme:DNA complex. Oligonucleotides containing a single CpG site form reversible 1:1 complexes with the enzyme that are sequence-specific. A guanine/cytosine-rich 30 base-pair sequence, a mimic of the GC-box cis-element, bound threefold more tightly than an adenine/thymine-rich sequence, a mimic of the cyclic AMP responsive element. However, the binding discrimination between hemi- and unmethylated forms of these DNA substrates was small, as we previously observed at the K(m)DNA level (Biochemistry, 35, 7308-7315 (1996)). Single-stranded substrates are bound much more weakly than double-stranded DNA forms. An in vitro screening method was used to select for CpG flanking sequence preferences of the DNA methyltransferase from a large, divergent population of DNA substrates. After five iterative rounds of increasing selective pressure, guanosine/cytosine-rich sequences were abundant and contributed to binding stabilization for at least 12 base-pairs on either side of a central CpG. Our results suggest a read-out of sequence-dependent conformational features, such as helical flexibility, minor groove dimensions and critical phosphate orientation and mobility, rather than interactions with specific bases over the course of two complete helical turns. Thus, both studies reveal a preference for guanosine/cytosine deoxynucleotides flanking the cognate CpG. The enzyme specificity for similar sequences in the genome may contribute to the in vivo functions of this vital enzyme.
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Affiliation(s)
- J Flynn
- Department of Chemistry, University of California, Santa Barbara 93106, USA
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Newlands ES, Stevens MF, Wedge SR, Wheelhouse RT, Brock C. Temozolomide: a review of its discovery, chemical properties, pre-clinical development and clinical trials. Cancer Treat Rev 1997; 23:35-61. [PMID: 9189180 DOI: 10.1016/s0305-7372(97)90019-0] [Citation(s) in RCA: 541] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- E S Newlands
- Department of Medical Oncology, Charing Cross Hospital, London, U.K
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30
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Kim YI, Salomon RN, Graeme-Cook F, Choi SW, Smith DE, Dallal GE, Mason JB. Dietary folate protects against the development of macroscopic colonic neoplasia in a dose responsive manner in rats. Gut 1996; 39:732-40. [PMID: 9014775 PMCID: PMC1383400 DOI: 10.1136/gut.39.5.732] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND AIMS Diminished folate status is associated with enhanced colorectal carcinogenesis. This study investigated the potential chemopreventive role of dietary folate in the dimethylhydrazine colorectal cancer model. SUBJECTS AND METHODS Sprague-Dawley rats were fed diets containing either 0, 2 (daily dietary requirement), 8 or 40 mg folate/kg diet for 20 weeks. After five weeks of diet, rats were injected with dimethyl-hydrazine (44 mg/kg) weekly for 15 weeks. Fifteen weeks after the first injection of dimethylhydrazine, all rats were killed. Folate status was determined, and the entire colorectum from each rat was analysed for macroscopic and microscopic neoplasms. RESULTS Plasma and colonic folate concentrations correlated directly with dietary folate levels (p < 0.005). The incidence of microscopic neoplasms was similar among the four groups. However, the incidence and the average number of macroscopic tumours per rat decreased progressively with increasing dietary folate levels up to 8 mg/kg diet (p < 0.05). In the strongly procarcinogenic milieu used in this study, folate supplementation at 20 times the basal requirement was associated with rates of macroscopic tumour development that were intermediate, and not statistically distinct, from rates observed at either 0 or 8 mg/kg diet. CONCLUSIONS These data indicate that in this rat model, (a) increasing dietary folate up to four times the basal requirement leads to a progressive reduction in the evolution of macroscopic neoplasms from microscopic foci; and (b) folate supplementation beyond four times the requirement does not convey further benefit.
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Affiliation(s)
- Y I Kim
- Vitamin Bioavailability Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA
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31
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Abstract
Recent studies of mice lacking methyltransferase, and of genes that modify cancer susceptibility, have shed light on the long-standing problem of how DNA methylation affects carcinogenesis.
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Affiliation(s)
- A Balmain
- Department of Medical Oncology, University of Glasgow, Bearsden, UK
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32
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Counts JL, Goodman JI. Hypomethylation of DNA: an epigenetic mechanism involved in tumor promotion. Mol Carcinog 1994; 11:185-8. [PMID: 7999259 DOI: 10.1002/mc.2940110402] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- J L Counts
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing 48824
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33
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Spencer PS, Allen CN, Kisby GE, Ludolph AC. On the etiology and pathogenesis of chemically induced neurodegenerative disorders. Neurobiol Aging 1994; 15:265-7. [PMID: 7838308 DOI: 10.1016/0197-4580(94)90129-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- P S Spencer
- Center for Research on Occupational and Environmental Toxicology, Oregon Health Sciences University, Portland 97201
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Smith SS. Biological implications of the mechanism of action of human DNA (cytosine-5)methyltransferase. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1994; 49:65-111. [PMID: 7863011 DOI: 10.1016/s0079-6603(08)60048-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- S S Smith
- Department of Cell and Tumor Biology, City of Hope National Medical Center, Duarte, California 91010
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