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Zohud O, Lone IM, Nashef A, Iraqi FA. Towards system genetics analysis of head and neck squamous cell carcinoma using the mouse model, cellular platform, and clinical human data. Animal Model Exp Med 2023; 6:537-558. [PMID: 38129938 PMCID: PMC10757216 DOI: 10.1002/ame2.12367] [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: 08/24/2023] [Accepted: 11/21/2023] [Indexed: 12/23/2023] Open
Abstract
Head and neck squamous cell cancer (HNSCC) is a leading global malignancy. Every year, More than 830 000 people are diagnosed with HNSCC globally, with more than 430 000 fatalities. HNSCC is a deadly diverse malignancy with many tumor locations and biological characteristics. It originates from the squamous epithelium of the oral cavity, oropharynx, nasopharynx, larynx, and hypopharynx. The most frequently impacted regions are the tongue and larynx. Previous investigations have demonstrated the critical role of host genetic susceptibility in the progression of HNSCC. Despite the advances in our knowledge, the improved survival rate of HNSCC patients over the last 40 years has been limited. Failure to identify the molecular origins of development of HNSCC and the genetic basis of the disease and its biological heterogeneity impedes the development of new therapeutic methods. These results indicate a need to identify more genetic factors underlying this complex disease, which can be better used in early detection and prevention strategies. The lack of reliable animal models to investigate the underlying molecular processes is one of the most significant barriers to understanding HNSCC tumors. In this report, we explore and discuss potential research prospects utilizing the Collaborative Cross mouse model and crossing it to mice carrying single or double knockout genes (e.g. Smad4 and P53 genes) to identify genetic factors affecting the development of this complex disease using genome-wide association studies, epigenetics, microRNA, long noncoding RNA, lncRNA, histone modifications, methylation, phosphorylation, and proteomics.
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Affiliation(s)
- Osayd Zohud
- Department of Clinical Microbiology and Immunology, Sackler Faculty of MedicineTel‐Aviv UniversityTel AvivIsrael
| | - Iqbal M. Lone
- Department of Clinical Microbiology and Immunology, Sackler Faculty of MedicineTel‐Aviv UniversityTel AvivIsrael
| | - Aysar Nashef
- Department of Oral and Maxillofacial SurgeryBaruch Padeh Medical CenterPoriyaIsrael
- Azrieli Faculty of MedicineBar‐Ilan UniversityRamat GanIsrael
| | - Fuad A. Iraqi
- Department of Clinical Microbiology and Immunology, Sackler Faculty of MedicineTel‐Aviv UniversityTel AvivIsrael
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Romualdo GR, Heidor R, Bacil GP, Moreno FS, Barbisan LF. Past, present, and future of chemically induced hepatocarcinogenesis rodent models: Perspectives concerning classic and new cancer hallmarks. Life Sci 2023; 330:121994. [PMID: 37543357 DOI: 10.1016/j.lfs.2023.121994] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/25/2023] [Accepted: 07/29/2023] [Indexed: 08/07/2023]
Abstract
Hepatocellular carcinoma (HCC), the main primary liver cancer, accounts for 5 % of all incident cases and 8.4 % of all cancer-related deaths worldwide. HCC displays a spectrum of environmental risk factors (viral chronic infections, aflatoxin exposure, alcoholic- and nonalcoholic fatty liver diseases) that result in molecular complexity and heterogeneity, contributing to a rising epidemiological burden, poor prognosis, and non-satisfactory treatment options. The emergence of HCC (i.e., hepatocarcinogenesis) is a multistep and complex process that addresses many (epi)genetic alterations and phenotypic traits, the so-called cancer hallmarks. "Polymorphic microbiomes", "epigenetic reprogramming", "senescent cells" and "unlocking phenotypic plasticity" are trending hallmarks/enabling features in cancer biology. As the main molecular drivers of HCC are still undruggable, chemically induced in vivo models of hepatocarcinogenesis are useful tools in preclinical research. Thus, this narrative review aimed at recapitulating the basic features of chemically induced rodent models of hepatocarcinogenesis, eliciting their permanent translational value regarding the "classic" and the "new" cancer hallmarks/enabling features. We gathered state-of-art preclinical evidence on non-cirrhotic, inflammation-, alcoholic liver disease- and nonalcoholic fatty liver-associated HCC models, demonstrating that these bioassays indeed express the recently added hallmarks, as well as reflect the interplay between classical and new cancer traits. Our review demonstrated that these protocols remain valuable for translational preclinical application, as they recapitulate trending features of cancer science. Further "omics-based" approaches are warranted while multimodel investigations are encouraged in order to avoid "model-biased" responses.
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Affiliation(s)
- Guilherme Ribeiro Romualdo
- São Paulo State University (UNESP), Botucatu Medical School, Experimental Research Unit (UNIPEX), Multimodel Drug Screening Platform - Laboratory of Chemically Induced and Experimental Carcinogenesis (MDSP-LCQE), Botucatu, SP, Brazil; São Paulo State University (UNESP), Biosciences Institute, Department of Structural and Functional Biology, Laboratory of Chemically Induced and Experimental Carcinogenesis (LCQE), Botucatu, SP, Brazil; São Paulo State University (UNESP), Botucatu Medical School, Botucatu, SP, Brazil
| | - Renato Heidor
- University of São Paulo (USP), Faculty of Pharmaceutical Sciences, Department of Food and Experimental Nutrition, Laboratory of Diet, Nutrition, and Cancer, São Paulo, SP, Brazil
| | - Gabriel Prata Bacil
- São Paulo State University (UNESP), Biosciences Institute, Department of Structural and Functional Biology, Laboratory of Chemically Induced and Experimental Carcinogenesis (LCQE), Botucatu, SP, Brazil; São Paulo State University (UNESP), Botucatu Medical School, Botucatu, SP, Brazil
| | - Fernando Salvador Moreno
- University of São Paulo (USP), Faculty of Pharmaceutical Sciences, Department of Food and Experimental Nutrition, Laboratory of Diet, Nutrition, and Cancer, São Paulo, SP, Brazil
| | - Luís Fernando Barbisan
- São Paulo State University (UNESP), Botucatu Medical School, Experimental Research Unit (UNIPEX), Multimodel Drug Screening Platform - Laboratory of Chemically Induced and Experimental Carcinogenesis (MDSP-LCQE), Botucatu, SP, Brazil; São Paulo State University (UNESP), Biosciences Institute, Department of Structural and Functional Biology, Laboratory of Chemically Induced and Experimental Carcinogenesis (LCQE), Botucatu, SP, Brazil; São Paulo State University (UNESP), Botucatu Medical School, Botucatu, SP, Brazil.
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Maleknia M, Ahmadirad N, Golab F, Katebi Y, Haj Mohamad Ebrahim Ketabforoush A. DNA Methylation in Cancer: Epigenetic View of Dietary and Lifestyle Factors. Epigenet Insights 2023; 16:25168657231199893. [PMID: 37720354 PMCID: PMC10504848 DOI: 10.1177/25168657231199893] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 08/22/2023] [Indexed: 09/19/2023] Open
Abstract
Background Alterations in DNA methylation play an important role in cancer development and progression. Dietary nutrients and lifestyle behaviors can influence DNA methylation patterns and thereby modulate cancer risk. Introduction To comprehensively review available evidence on how dietary and lifestyle factors impact DNA methylation and contribute to carcinogenesis through epigenetic mechanisms. Materials and methods A literature search was conducted using PubMed to identify relevant studies published between 2005 and 2022 that examined relationships between dietary/lifestyle factors and DNA methylation in cancer. Studies investigating the effects of dietary components (eg, micronutrients, phytochemicals), physical activity, smoking, and obesity on global and gene-specific DNA methylation changes in animal and human cancer models were included. Data on specific dietary/lifestyle exposures, cancer types, DNA methylation targets and underlying mechanisms were extracted. Results Multiple dietary and lifestyle factors were found to influence DNA methylation patterns through effects on DNA methyltransferase activity, methyl donor availability, and generation of oxidative stress. Altered methylation of specific genes regulating cell proliferation, apoptosis, and inflammation were linked to cancer development and progression. Conclusion Dietary and lifestyle interventions aimed at modulating DNA methylation have potential for both cancer prevention and treatment through epigenetic mechanisms. Further research is needed to identify actionable targets for nutrition and lifestyle-based epigenetic therapies.
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Affiliation(s)
- Mohsen Maleknia
- Noorgene Genetic & Clinical Laboratory, Molecular Research Center, Ahvaz, Iran
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Nooshin Ahmadirad
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Fereshteh Golab
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Yasmina Katebi
- Faculty of Life Sciences and Biotechnology, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Sharma R, Ali T, Kaur J. Folic acid depletion as well as oversupplementation helps in the progression of hepatocarcinogenesis in HepG2 cells. Sci Rep 2022; 12:16617. [PMID: 36198749 PMCID: PMC9534894 DOI: 10.1038/s41598-022-21084-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 09/22/2022] [Indexed: 12/04/2022] Open
Abstract
Folate ingestion below and above the physiologic dose has been shown to play a tumorigenic role in certain cancers. Also, excessive folate supplementation after establishment of pre-established lesions led to an advancement in the growth of a few tumors. However, such information has not yet been achieved in the case of HCC. In our study, HepG2 cells were administered with three different concentrations of folic acid i.e. folic acid normal (FN) (2.27 µM), folic acid deficient (FD) (no folic acid), folic acid oversupplementation (FO) (100 µM) for 10 days. Intracellular folate levels were assayed by Elecsys Folate III kit based method. The migratory and invasive abilities were estimated by transwell migration and matrigel invasion methods respectively. FACS was done to evaluate cell viability and apoptosis. Agarose-coated plates were used to access cancer stem cells (CSCs) number. Quantitative RT-PCR and western blotting approaches were used for gene and protein expression of certain tumor suppressor genes (TSGs), respectively. FD cells depicted increased migration, invasion, apoptosis, necrosis and decreased cell viability, CSCs. On the other hand, FO cells showed increased migration, invasion, cell viability and number of CSCs and decreased apoptosis and necrosis. TSGs revealed diminished expression with both FA modulations with respect to FN cells. Thus, FA deficiency as well as abundance enhanced the HCC progression by adapting different mechanisms.
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Affiliation(s)
- Renuka Sharma
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, PGIMER, Chandigarh, India
| | - Taqveema Ali
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, PGIMER, Chandigarh, India
| | - Jyotdeep Kaur
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, PGIMER, Chandigarh, India.
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Sharma R, Ali T, Kaur J. Tumor suppressor genes are differentially regulated with dietary folate modulations in a rat model of hepatocellular carcinoma. Mol Cell Biochem 2020; 476:385-399. [PMID: 32974832 DOI: 10.1007/s11010-020-03915-3] [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: 07/06/2020] [Accepted: 09/15/2020] [Indexed: 11/30/2022]
Abstract
The current study evaluated the outcome of dietary folate modulations on the expression of tumor suppressor genes (TSGs) during developmental stages of hepatocellular carcinoma (HCC) in a Wistar rat model. In addition to dietary folate modulations, male rats were administered diethylnitrosamine (DEN) intraperitoneally once a week upto 18 weeks to induce HCC. Serum folate levels were found to be decreased and increased in folate deficiency (FD) and folate-oversupplemented (FO) groups respectively when compared to folate normal (FN) rats. Apoptosis was observed in FD in fibrosis and HCC stages. mRNA expression analysis by RT-PCR of TSGs (DPT, p16, RUNX3, RASSF1A and SOCS1) and protein expression by western blot (RASSF1A, RUNX3 and p16) depicted differential expression in FD and FO in various stages of HCC development. Bisulfite sequencing for p16 and RASSF1A promoter was performed. The promoter region of p16 gene was hypermethylated at 7th and that of RASSF1A was hypomethylated at 10th CpG in cirrhotic category in FD rats. Hyper and hypomethylation at 10th and 24th CpG respectively in RASSF1A promoter was observed in HCC category in both FD and FO groups. All TSGs showed differential expression at transcript and protein level. Increased expression of DPT, RASSF1A, SOCS1 and decreased expression of RUNX3 could be playing role in HCC development in FD rats. Reduced expression of RUNX3, RASSF1A and SOCS1 in HCC category was demonstrated in FO rats. Thus, the studied TSGs are differentially expressed with dietary folate modulations during the development of HCC in DEN-treated rat model and the promoter methylation might be a contributing mechanism under these conditions.
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Affiliation(s)
- Renuka Sharma
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Taqveema Ali
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Jyotdeep Kaur
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
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Li S, Chen M, Li Y, Tollefsbol TO. Prenatal epigenetics diets play protective roles against environmental pollution. Clin Epigenetics 2019; 11:82. [PMID: 31097039 PMCID: PMC6524340 DOI: 10.1186/s13148-019-0659-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 03/27/2019] [Indexed: 12/12/2022] Open
Abstract
It is thought that germ cells and preimplantation embryos during development are most susceptible to endogenous and exogenous environmental factors because the epigenome in those cells is undergoing dramatic elimination and reconstruction. Exposure to environmental factors such as nutrition, climate, stress, pathogens, toxins, and even social behavior during gametogenesis and early embryogenesis has been shown to influence disease susceptibility in the offspring. Early-life epigenetic modifications, which determine the expression of genetic information stored in the genome, are viewed as one of the general mechanisms linking prenatal exposure and phenotypic changes later in life. From atmospheric pollution, endocrine-disrupting chemicals to heavy metals, research increasingly suggests that environmental pollutions have already produced significant consequences on human health. Moreover, mounting evidence now links such pollution to relevant modification in the epigenome. The epigenetics diet, referring to a class of bioactive dietary compounds such as isothiocyanates in broccoli, genistein in soybean, resveratrol in grape, epigallocatechin-3-gallate in green tea, and ascorbic acid in fruits, has been shown to modify the epigenome leading to beneficial health outcomes. This review will primarily focus on the causes and consequences of prenatal environment pollution exposure on the epigenome, and the potential protective role of the epigenetics diet, which could play a central role in neutralizing epigenomic aberrations against environmental pollutions.
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Affiliation(s)
- Shizhao Li
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Min Chen
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Yuanyuan Li
- Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL, USA.
- Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA.
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
| | - Trygve O Tollefsbol
- Department of Biology, University of Alabama at Birmingham, Birmingham, AL, USA.
- Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA.
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham, AL, USA.
- Comprehensive Center for Healthy Aging, University of Alabama at Birmingham, Birmingham, AL, USA.
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL, USA.
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Najar RA, Wani NA, Bhat JA, Dar NJ, Rahat B, Gupta AP, Kaur J, Kaur J, Hamid A. Modulation of dietary folate with age confers selective hepatocellular epigenetic imprints through DNA methylation. J Nutr Biochem 2018; 53:121-132. [PMID: 29220669 DOI: 10.1016/j.jnutbio.2017.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/15/2017] [Accepted: 10/16/2017] [Indexed: 02/03/2023]
Abstract
The present study has been designed to determine the effect of folate modulation (deficiency/supplementation) with aging on the promoter methylation of tumor suppressor and proto-oncogenes to understand the underlying mechanism of epigenetic alterations. Folate deficiency was induced for 3 and 5 months in weanling, young and adult groups, and after 3 months of folate deficiency, they were repleted with physiological folate (2 mg/kg diet) and folate oversupplementation (8 mg/kg diet) for another 2 months. The methylation facet in the present study revealed that the combined effect of folate deficiency and aging decreased the methylation index. Folate deficiency with age resulted in the up-regulation of proto-oncogenes (C-MYC and C-JUN) and cell cycle regulator gene Cyclin E as a result of promoter hypomethylation. However, in case of tumor suppressor genes (p53, p15ink4b and p16ink4a), the expression levels were found to be decreased at transcriptional level due to promoter hypermethylation. Upon repletion with physiological folate and folate oversupplementation, we found down-regulation of proto-oncogenes and up-regulation of tumor suppressor genes as a result of promoter hypermethylation and hypomethylation, respectively. Deregulation of these important genes due to folate deficiency may contribute toward the pathogenesis at cellular level.
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Affiliation(s)
- Rauf Ahmad Najar
- Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Jammu 180001, India
| | - Nissar Ahmad Wani
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Javeed Ahmad Bhat
- Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Jammu 180001, India
| | - Nawab John Dar
- Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Jammu 180001, India
| | - Beenish Rahat
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Ajai Prakash Gupta
- Quality Control and Quality Assurance Division, CSIR- Indian Institute of Integrative Medicine, Jammu 180001, India
| | - Jaspreet Kaur
- University Institute of Engineering and Technology, Panjab University, Chandigarh 160016, India
| | - Jyotdeep Kaur
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India
| | - Abid Hamid
- Cancer Pharmacology Division, CSIR-Indian Institute of Integrative Medicine, Jammu 180001, India.
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Bartosch C, Lopes JM, Jerónimo C. Epigenetics in endometrial carcinogenesis - part 1: DNA methylation. Epigenomics 2017; 9:737-755. [PMID: 28470096 DOI: 10.2217/epi-2016-0166] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Carcinogenesis is a multistep multifactorial process that involves the accumulation of genetic and epigenetic alterations. In the past two decades, there has been an exponential growth of knowledge establishing the importance of epigenetic changes in cancer. Our work focused on reviewing the main role of epigenetics in the pathogenesis of endometrial carcinoma, highlighting the reported results concerning each epigenetic mechanistic layer. The present review is the first part of this work, in which we examined the contribution of DNA methylation alterations for endometrial carcinogenesis.
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Affiliation(s)
- Carla Bartosch
- Department of Pathology, Portuguese Oncology Institute of Porto (IPO-Porto), Porto, Portugal.,Cancer Biology & Epigenetics Group, Research Center (CI-IPOP), Portuguese Oncology Institute of Porto, Porto, Portugal.,Department of Pathology & Oncology, Medical Faculty, University of Porto, Porto, Portugal.,Porto Comprehensive Cancer Center (P.ccc), Porto, Portugal
| | - José Manuel Lopes
- Department of Pathology & Oncology, Medical Faculty, University of Porto, Porto, Portugal.,Department of Pathology, Centro Hospitalar São João (CHSJ), Porto, Portugal.,IPATIMUP - Institute of Molecular Pathology & Immunology, University of Porto, Porto, Portugal.,I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
| | - Carmen Jerónimo
- Cancer Biology & Epigenetics Group, Research Center (CI-IPOP), Portuguese Oncology Institute of Porto, Porto, Portugal.,Porto Comprehensive Cancer Center (P.ccc), Porto, Portugal.,Department of Pathology & Molecular Immunology, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
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Gorelova V, Ambach L, Rébeillé F, Stove C, Van Der Straeten D. Folates in Plants: Research Advances and Progress in Crop Biofortification. Front Chem 2017; 5:21. [PMID: 28424769 PMCID: PMC5372827 DOI: 10.3389/fchem.2017.00021] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/09/2017] [Indexed: 11/13/2022] Open
Abstract
Folates, also known as B9 vitamins, serve as donors and acceptors in one-carbon (C1) transfer reactions. The latter are involved in synthesis of many important biomolecules, such as amino acids, nucleic acids and vitamin B5. Folates also play a central role in the methyl cycle that provides one-carbon groups for methylation reactions. The important functions fulfilled by folates make them essential in all living organisms. Plants, being able to synthesize folates de novo, serve as an excellent dietary source of folates for animals that lack the respective biosynthetic pathway. Unfortunately, the most important staple crops such as rice, potato and maize are rather poor sources of folates. Insufficient folate consumption is known to cause severe developmental disorders in humans. Two approaches are employed to fight folate deficiency: pharmacological supplementation in the form of folate pills and biofortification of staple crops. As the former approach is considered rather costly for the major part of the world population, biofortification of staple crops is viewed as a decent alternative in the struggle against folate deficiency. Therefore, strategies, challenges and recent progress of folate enhancement in plants will be addressed in this review. Apart from the ever-growing need for the enhancement of nutritional quality of crops, the world population faces climate change catastrophes or environmental stresses, such as elevated temperatures, drought, salinity that severely affect growth and productivity of crops. Due to immense diversity of their biochemical functions, folates take part in virtually every aspect of plant physiology. Any disturbance to the plant folate metabolism leads to severe growth inhibition and, as a consequence, to a lower productivity. Whereas today's knowledge of folate biochemistry can be considered very profound, evidence on the physiological roles of folates in plants only starts to emerge. In the current review we will discuss the implication of folates in various aspects of plant physiology and development.
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Affiliation(s)
- Vera Gorelova
- Laboratory of Functional Plant Biology, Department of Biology, Ghent UniversityGhent, Belgium
| | - Lars Ambach
- Laboratory of Toxicology, Department of Bioanalysis, Ghent UniversityGhent, Belgium
| | - Fabrice Rébeillé
- Laboratoire de Physiologie Cellulaire Végétale, Bioscience and Biotechnologies Institute of Grenoble, CEA-GrenobleGrenoble, France
| | - Christophe Stove
- Laboratory of Toxicology, Department of Bioanalysis, Ghent UniversityGhent, Belgium
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Oleinik NV, Helke KL, Kistner-Griffin E, Krupenko NI, Krupenko SA. Rho GTPases RhoA and Rac1 mediate effects of dietary folate on metastatic potential of A549 cancer cells through the control of cofilin phosphorylation. J Biol Chem 2014; 289:26383-26394. [PMID: 25086046 DOI: 10.1074/jbc.m114.569657] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Folate, an important nutrient in the human diet, has been implicated in cancer, but its role in metastasis is not established. We have shown previously that the withdrawal of medium folate leads to the inhibition of migration and invasion of A549 lung carcinoma cells. Here we have demonstrated that medium folate regulates the function of Rho GTPases by enabling their carboxyl methylation and translocation to plasma membrane. Conversely, the lack of folate leads to the retention of these proteins in endoplasmic reticulum. Folate also promoted the switch from inactive (GDP-bound) to active (GTP-bound) GTPases, resulting in the activation of downstream kinases p21-activated kinase and LIM kinase and phosphorylation of the actin-depolymerizing factor cofilin. We have further demonstrated that in A549 cells two GTPases, RhoA and Rac1, but not Cdc42, are immediate sensors of folate status: the siRNA silencing of RhoA or Rac1 blocked effects of folate on cofilin phosphorylation and cellular migration and invasion. The finding that folate modulates metastatic potential of cancer cells was confirmed in an animal model of lung cancer using tail vein injection of A549 cells in SCID mice. A folate-rich diet enhanced lung colonization and distant metastasis to lymph nodes and decreased overall survival (35 versus 63 days for mice on a folate-restricted diet). High folate also promoted epithelial-mesenchymal transition in cancer cells and experimental mouse tumors. Our study provides experimental evidence for a mechanism of metastasis promotion by dietary folate and highlights the interaction between nutrients and metastasis-related signaling.
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Affiliation(s)
- Natalia V Oleinik
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kristi L Helke
- Comparative Medicine and Laboratory Animal Resources, and Medical University of South Carolina, Charleston, South Carolina 29425
| | - Emily Kistner-Griffin
- Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Natalia I Krupenko
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425; Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Sergey A Krupenko
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425; Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina 29425.
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Wang CX, Wang X, Liu HB, Zhou ZH. Aberrant DNA methylation and epigenetic inactivation of hMSH2 decrease overall survival of acute lymphoblastic leukemia patients via modulating cell cycle and apoptosis. Asian Pac J Cancer Prev 2014; 15:355-62. [PMID: 24528056 DOI: 10.7314/apjcp.2014.15.1.355] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Altered regulation of many transcription factors has been shown to play important roles in the development of leukemia. hMSH2 can modulate the activity of some important transcription factors and is known to be a regulator of hematopoietic differentiation. Herein, we investigated epigenetic regulation of hMSH2 and its influence on cell growth and overall survival of acute lymphoblastic leukemia (ALL) patients. METHODS hMSH2 promoter methylation status was assessed by COBRA and pyrosequencing in 60 ALL patients and 30 healthy volunteers. mRNA and protein expression levels of hMSH2, PCNA, CyclinD1, Bcl-2 and Bax were determined by real time PCR and Western blotting, respectively. The influence of hMSH2 on cell proliferation and survival was assessed in transient and stable expression systems. RESULTS mRNA and protein expression of hMSH2 and Bcl-2 was decreased, and that of PCNA, CyclinD1 and Bax was increased in ALL patients as compared to healthy volunteers (P<0.05). hMSH2 was inactivated in ALL patients through promoter hypermethylation. Furthermore, hMSH2 hypermethylation was found in relapsed ALL patients (85.7% of all cases). The median survival of patients with hMSH2 methylation was shorter than that of patients without hMSH2 methylation (log-rank test, P=0.0035). Over-expression of hMSH2 in cell lines resulted in a significant reduction in growth and induction of apoptosis. CONCLUSIONS This study suggests that aberrant DNA methylation and epigenetic inactivation of hMSH2 play an important role in the development of ALL through altering cell growth and survival.
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Affiliation(s)
- Cai-Xia Wang
- Department of Internal Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China E-mail :
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Abstract
Mechanisms postulated to link folate and B12 metabolism with cancer, including genome-wide hypomethylation, gene-specific promoter hypermethylation, and DNA uracil misincorporation, have been observed in prostate tumor cells. However, epidemiological studies of prostate cancer risk, based on dietary intakes and blood levels of folate and vitamin B12 and on folate-pathway gene variants, have generated contradictory findings. In a meta-analysis, circulating concentrations of B12 (seven studies, OR = 1.10; 95% CI 1.01, 1.19; P = 0.002) and (in cohort studies) folate (five studies, OR = 1.18; 95% CI 1.00, 1.40; P = 0.02) were positively associated with an increased risk of prostate cancer. Homocysteine was not associated with risk of prostate cancer (four studies, OR = 0.91; 95% CI 0.69, 1.19; P = 0.5). In a meta-analysis of folate-pathway polymorphisms, MTR 2756A > G (eight studies, OR = 1.06; 95% CI 1.00, 1.12; P = 0.06) and SHMT1 1420C > T (two studies, OR = 1.11; 95% CI 1.00, 1.22; P = 0.05) were positively associated with prostate cancer risk. There were no effects due to any other polymorphisms, including MTHFR 677C > T (12 studies, OR = 1.04; 95% CI 0.97, 1.12; P = 0.3). The positive association of circulating B12 with an increased risk of prostate cancer could be explained by reverse causality. However, given current controversies over mandatory B12 fortification, further research to eliminate a causal role of B12 in prostate cancer initiation and/or progression is required. Meta-analysis does not entirely rule out a positive association of circulating folate with increased prostate cancer risk. As with B12, even a weak positive association would be a significant public health issue, given the high prevalence of prostate cancer and concerns about the potential harms versus benefits of mandatory folic acid fortification.
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Long C, He J, Liu X, Chen X, Gao R, Wang Y, Ding Y. Dietary folate deficiency in pseudopregnant mice has no effect on homeobox A10 promoter methylation or expression. Reprod Sci 2012; 19:1268-75. [PMID: 22786609 DOI: 10.1177/1933719112447125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
During the reproductive cycle, a number of genes controlling endometrial changes are regulated by DNA methylation, a common epigenetic modification. Because dietary folate affects DNA methylation, we determined whether a folate-deficient diet (FDD) alters DNA methylation in endometria of pseudopregnant mice, focusing on the homeobox A10 (Hoxa10) promoter. Mice were given an FDD or control diet for 40 to 45 days and examined on day 5 of pseudopregnancy. Compared to control mice, FDD mice had lower folate levels in liver and serum (P = .004). However, the FDD did not significantly affect DNA methylation within the cytosine-guanine dinucleotide (CpG)-rich Hoxa10 promoter, even when specific CpG sites were examined (P > .05). In endometrial tissue sections, the localization of anti-Hoxa10 staining was unchanged in FDD mice. Therefore, folate deficiency did not significantly affect promoter methylation or expression of Hoxa10.
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Affiliation(s)
- Chunlan Long
- Laboratory of Reproductive Biology, Chongqing Medical University, Chongqing, People's Republic of China
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14
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Ding YB, He JL, Liu XQ, Chen XM, Long CL, Wang YX. Expression of DNA methyltransferases in the mouse uterus during early pregnancy and susceptibility to dietary folate deficiency. Reproduction 2012; 144:91-100. [PMID: 22580371 DOI: 10.1530/rep-12-0006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
We have characterized the uterine expression of DNA methyltransferases (DNMTs) during early pregnancy in mice and determined whether a folate-deficient diet (FDD) can affect DNMTs in this context. Within endometrial cells, expressions of DNMT (cytosine-5) 1 (Dnmt1), Dnmt3a, and Dnmt3b were significantly elevated during the prereceptive phase of pregnancy but generally returned to baseline levels during receptive and postimplantation periods. As such, the transcription of DNMT genes is temporally regulated during early pregnancy. When comparisons were made between implantation sites (IS) and inter-IS on day 5 of pregnancy, lower levels of Dnmt3a were detected at IS. Comparisons between IS and inter-IS did not reveal significant expression differences for other DNMT genes. When tissue sections were examined, DNMT3A was specifically lower in the stroma of IS. Reduced DNMT1 and DNMT3B levels were also observed in the luminal and glandular epithelia of IS, whereas no obvious differences in the stroma were detected. In pseudo-pregnant mice subjected to a FDD, levels of Dnmt1 and Dnmt3a (but not Dnmt3b) were significantly upregulated in endometrial tissues, as compared with controls. When tissues from these folate-deficient mice were examined, DNMT1 levels were elevated in both the luminal and glandular epithelia, whereas DNMT3A was upregulated in the luminal epithelium and the stroma. A slight increase in DNMT3B levels was detected in the glandular epithelium. These results indicate that DNMTs may regulate the transcription of endometrial genes associated with embryo implantation and that levels of DNMTs are affected by dietary folate in mice.
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Affiliation(s)
- Y B Ding
- Department of Reproductive Biology, Chongqing Medical University, Box 197, No. 1 Yixueyuan Road, Chongqing 400016, People's Republic of China
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15
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Blusztajn JK, Mellott TJ. Choline nutrition programs brain development via DNA and histone methylation. Cent Nerv Syst Agents Med Chem 2012; 12:82-94. [PMID: 22483275 PMCID: PMC5612430 DOI: 10.2174/187152412800792706] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 12/05/2011] [Accepted: 12/06/2011] [Indexed: 11/22/2022]
Abstract
Choline is an essential nutrient for humans. Metabolically choline is used for the synthesis of membrane phospholipids (e.g. phosphatidylcholine), as a precursor of the neurotransmitter acetylcholine, and, following oxidation to betaine, choline functions as a methyl group donor in a pathway that produces S-adenosylmethionine. As a methyl donor choline influences DNA and histone methylation--two central epigenomic processes that regulate gene expression. Because the fetus and neonate have high demands for choline, its dietary intake during pregnancy and lactation is particularly important for normal development of the offspring. Studies in rodents have shown that high choline intake during gestation improves cognitive function in adulthood and prevents memory decline associated with old age. These behavioral changes are accompanied by electrophysiological, neuroanatomical, and neurochemical changes and by altered patterns of expression of multiple cortical and hippocampal genes including those encoding key proteins that contribute to the biochemical mechanisms of learning and memory. These actions of choline are observed long after the exposure to the nutrient ended (months) and correlate with fetal hepatic and cerebral cortical choline-evoked changes in global- and gene-specific DNA cytosine methylation and with dramatic changes of the methylation pattern of lysine residues 4, 9 and 27 of histone H3. Moreover, gestational choline modulates the expression of DNA (Dnmt1, Dnmt3a) and histone (G9a/Ehmt2/Kmt1c, Suv39h1/Kmt1a) methyltransferases. In addition to the central role of DNA and histone methylation in brain development, these processes are highly dynamic in adult brain, modulate the expression of genes critical for synaptic plasticity, and are involved in mechanisms of learning and memory. A recent study documented that in a cohort of normal elderly people, verbal and visual memory function correlated positively with the amount of dietary choline consumption. It will be important to determine if these actions of choline on human cognition are mediated by epigenomic mechanisms or by its influence on acetylcholine or phospholipid synthesis.
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Affiliation(s)
- Jan Krzysztof Blusztajn
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, 72 East Concord Street, L808, Boston, MA 02118, USA.
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16
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Hamid A. Folate malabsorption and its influence on DNA methylation during cancer development. DNA Cell Biol 2012. [PMID: 22468673 DOI: 10.1089/dna.2011.1576] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The folate transport across the epithelial of the intestine, colon, kidney, and liver is essential for folate homeostasis. The relative localization of transporters in membranes is an important determinant for the vectorial flow of substrates across the epithelia. Folate deficiency is a highly prevalent vitamin deficiency in the world, and alcohol ingestion has been the major contributor. It can develop because of folate malabsorption in tissues, increased renal excretion dietary inadequacy, and altered hepatobiliary metabolism. Additionally, folate-mediated one-carbon metabolism is important for various cellular processes, including DNA synthesis and methylation. In this regard, the contribution of alcohol-associated and dietary folate deficiency to methylation patterns is under intense investigation, especially in cancer. The epigenetic events have increasing relevance in the development of strategies for early diagnosis, prevention, and treatment of cancer.
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Affiliation(s)
- Abid Hamid
- Cancer Pharmacology Division, Indian Institute of Integrative Medicine, CSIR, Jammu, India
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Ong TP, Moreno FS, Ross SA. Targeting the epigenome with bioactive food components for cancer prevention. JOURNAL OF NUTRIGENETICS AND NUTRIGENOMICS 2012; 4:275-92. [PMID: 22353664 DOI: 10.1159/000334585] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Epigenetic processes participate in cancer development and likely influence cancer prevention. Global DNA hypomethylation, gene promoter hypermethylation and aberrant histone post-translational modifications are hallmarks of neoplastic cells which have been associated with genomic instability and altered gene expression. Because epigenetic deregulation occurs early in carcinogenesis and is potentially reversible, intervention strategies targeting the epigenome have been proposed for cancer prevention. Bioactive food components (BFCs) with anticancer potential, including folate, polyphenols, selenium, retinoids, fatty acids, isothiocyanates and allyl compounds, influence DNA methylation and histone modification processes. Such activities have been shown to affect the expression of genes involved in cell proliferation, death and differentiation that are frequently altered in cancer. Although the epigenome represents a promising target for cancer prevention with BFCs, few studies have addressed the influence of dietary components on these mechanisms in vivo, particularly on the phenotype of humans, and thus the exact mechanisms whereby diet mediates an effect on cancer prevention remains unclear. Primary factors that should be elucidated include the effective doses and dose timing of BFCs to attain epigenetic effects. Because diet-epigenome interactions are likely to occur in utero, the impact of early-life nutrition on cancer risk programming should be further investigated.
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Affiliation(s)
- Thomas Prates Ong
- Laboratory of Diet, Nutrition and Cancer, Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
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18
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Ciappio ED, Mason JB, Crott JW. Maternal one-carbon nutrient intake and cancer risk in offspring. Nutr Rev 2012; 69:561-71. [PMID: 21967157 DOI: 10.1111/j.1753-4887.2011.00424.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Dietary intake of one-carbon nutrients, particularly folate, vitamin B(2) (riboflavin), vitamin B(6) , vitamin B(12) , and choline have been linked to the risk of cancers of the colon and breast in both human and animal studies. More recently, experimental and epidemiological data have emerged to suggest that maternal intake of these nutrients during gestation may also have an impact on the risk of cancer in offspring later in life. Given the plasticity of DNA methylation in the developing embryo and the established role of one-carbon metabolism in supporting biological methylation reactions, it is plausible that alterations in maternal one-carbon nutrient availability might induce subtle epigenetic changes in the developing embryo and fetus that persist into later life, altering the risk of tumorigenesis throughout the lifespan. This review summarizes the current literature on maternal one-carbon nutrient intake and offspring cancer risk, with an emphasis on cancers of the colon and breast, and discusses specific epigenetic modifications that may play a role in their pathogenesis.
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Affiliation(s)
- Eric D Ciappio
- Vitamins and Carcinogenesis Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts 02111, USA
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19
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Kordi-Tamandani DM, Ladies MAR, Hashemi M, Moazeni-Roodi AK, Krishna S, Torkamanzehi A. Analysis of p15INK4b and p16INK4a gene methylation in patients with oral squamous cell carcinoma. Biochem Genet 2012; 50:448-53. [PMID: 22212460 DOI: 10.1007/s10528-011-9489-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 10/28/2011] [Indexed: 02/02/2023]
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20
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Salbaum JM, Kappen C. Genetic and epigenomic footprints of folate. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 108:129-58. [PMID: 22656376 DOI: 10.1016/b978-0-12-398397-8.00006-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Dietary micronutrient composition has long been recognized as a determining factor for human health. Historically, biochemical research has successfully unraveled how vitamins serve as essential cofactors for enzymatic reactions in the biochemical machinery of the cell. Folate, also known as vitamin B9, follows this paradigm as well. Folate deficiency is linked to adverse health conditions, and dietary supplementation with folate has proven highly beneficial in the prevention of neural tube defects. With its function in single-carbon metabolism, folate levels affect nucleotide synthesis, with implications for cell proliferation, DNA repair, and genomic stability. Furthermore, by providing the single-carbon moiety in the synthesis pathway for S-adenosylmethionine, the main methyl donor in the cell, folate also impacts methylation reactions. It is this capacity that extends the reach of folate functions into the realm of epigenetics and gene regulation. Methylation reactions play a major role for several modalities of the epigenome. The specific methylation status of histones, noncoding RNAs, transcription factors, or DNA represents a significant determinant for the transcriptional output of a cell. Proper folate status is therefore necessary for a broad range of biological functions that go beyond the biochemistry of folate. In this review, we examine evolutionary, genetic, and epigenomic footprints of folate and the implications for human health.
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Affiliation(s)
- J Michael Salbaum
- Regulation of Gene Expression Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA
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Wani NA, Hamid A, Kaur J. Alcohol-associated folate disturbances result in altered methylation of folate-regulating genes. Mol Cell Biochem 2011; 363:157-66. [PMID: 22147198 DOI: 10.1007/s11010-011-1168-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 11/23/2011] [Indexed: 12/17/2022]
Abstract
Folate plays a critical role in maintaining normal metabolic, energy, differentiation and growth status of all mammalian cells. The steady-state accumulation of folate seems to depend on the activity of two enzymes: folylpolyglutamate synthetase (FPGS), which adds glutamate residues, and gamma-glutamyl hydrolase (GGH), which removes them, enabling it to be transported across the biological membranes. Overexpression of GGH and downregulation of FPGS would be expected to decrease intracellular folate in its polyglutamylated form, thereby increasing efflux of folate and its related molecules, which might lead to resistance to drugs or folate deficiency. The study was sought to delineate the activity of GGH and expression FPGS in tissues involved in folate homeostasis during alcoholism and the epigenetic regulation of these enzymes and transporters regulating intracellular folate levels. We determined the activity of GGH and expression of FPGS in tissues after 3 months of ethanol feeding to rats at 1 g/kg body weight/day. The results showed that there was not any significant change in the activity of folate hydrolyzing enzyme GGH in ethanol-fed rats while there was significant down regulation in the expression of FPGS. Ethanol feeding decreased the total as well as polyglutamated folate levels. There was tissue-specific hyper/hypo methylation of folate transporter genes viz. PCFT and RFC by chronic ethanol feeding. Moreover, hypermethylation of FPGS gene was observed in intestine and kidney without any change in methylation levels of GGH in the ethanol-fed rats. In conclusion, the initial deconjugation of polyglutamylated folate by GGH was not impaired in ethanol-fed rats while the conversion of monoglutamylated folate to polyglutamylated form might be impaired. There was tissue-specific altered methylation of folate transporter genes by chronic ethanol feeding.
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Affiliation(s)
- Nissar Ahmad Wani
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh 160 012, India
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22
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Pellanda H, Namour F, Fofou-Caillierez M, Bressenot A, Alberto JM, Chéry C, Ayav A, Bronowicki JP, Guéant JL, Forges T. A splicing variant leads to complete loss of function of betaine-homocysteine methyltransferase (BHMT) gene in hepatocellular carcinoma. Int J Biochem Cell Biol 2011; 44:385-92. [PMID: 22138536 DOI: 10.1016/j.biocel.2011.11.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 11/07/2011] [Accepted: 11/17/2011] [Indexed: 02/01/2023]
Abstract
The remethylation of homocyteine into methionine is catalyzed either by methionine synthase (MTR) or by betaine-homocysteine methyltransferase (BHMT), in the liver. Choline/betaine deficiency and impaired BHMT pathway have been associated with hepatocellular carcinogenesis, in animal models. The molecular mechanisms that impair the BHMT pathway are unknown. We aimed to investigate BHMT, BHMT2, and MTR expression in HepG2 cells and human hepatocarcinoma tissues. Transcripts were quantified by RT-qPCR and splicing was assessed by analysis of exon junctions and sequencing of variants. Protein expression was studied by Western Blot, immunohistochemistry and enzyme activity. Tumor tissue was compared with surrounding healthy tissue. RT-qPCR of HepG2 cells and of tumor samples showed a strong decrease of transcripts of BHMT and BHMT2, compared to normal. MTR transcript levels were not different. The decreased BHMT expression resulted from the transcription of a splicing variant that produced a frameshift in exon 4, with a premature termination codon in exon 5 and a loss of function of the gene. This splicing variant did not fit with any mechanism resulting from known splicing consensus sequences and was not detected in normal adult and fetal liver. Consistently, BHMT activity was abolished in HepG2 and protein expression was not detectable in HepG2 and in 5 of the 6 tumor samples, compared to normal tissues. In conclusion, a transcription variant of exon 4 produces a loss of function of BHMT in human hepatocarcinoma. Whether this abnormal transcription of BHMT is part or consequence of liver carcinogenesis should deserve further investigations.
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Affiliation(s)
- Hélène Pellanda
- INSERM U954 Nutrition, Genetics, and Environmental Risk Exposure, Faculté de Médecine, Nancy Université, 9 Avenue de Forêt de Haye, 54500 Vandoeuvre Nancy, France
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23
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Zhou ZH, Lei YX, Wang CX. Analysis of aberrant methylation in DNA repair genes during malignant transformation of human bronchial epithelial cells induced by cadmium. Toxicol Sci 2011; 125:412-7. [PMID: 22112500 DOI: 10.1093/toxsci/kfr320] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cadmium (Cd) and its compounds are well-known human carcinogens, but the mechanisms underlying the carcinogenesis are not entirely understood yet. Aberrant methylation was investigated in order to obtain insight into the DNA repair-related epigenetic mechanisms underlying CdCl(2)-induced malignant transformation of human bronchial epithelial cells (16HBE). Gene expression and DNA methylation were assessed in untreated control cells; 5th, 15th, and 35th passage of CdCl2-treated cells and tumorigenic cells (TCs) from nude mice by using high-performance liquid chromatography, real-time PCR, Western blot analysis, and methylation-specific PCR assay. During Cd-induced malignant transformation, global DNA methylation progressively increased and was associated with the overexpression of the DNA methyltransferase genes DNMT1 and DNMT3a but not DNMT3b. Expression of both the messenger RNA and proteins of the DNA repair genes (hMSH2, ERCC1, XRCC1, and hOGG1) progressively reduced and DNA damage increased with Cd-induced transformation. The promoter regions of hMSH2, ERCC1, XRCC1, and hOGG1 were heavily methylated in the 35th passage transformed cells and the TCs. The DNA demethylating agent 5-aza-2'-deoxycytidine could reverse the Cd-induced global DNA hypermethylation, DNMT hyperactivity, and the silencing of hMSH2, ERCC1, XRCC1, and hOGG1 in a time-dependent manner. The results indicate that DNMT1 and DNMT3a overexpression can result in global DNA hypermethylation and silencing of the hMSH2, ERCC1, XRCC1, and hOGG1 genes. They may partly explain the epigenetic mechanisms underlying the carcinogenesis due to Cd.
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Affiliation(s)
- Zhi-heng Zhou
- Department of Toxicology, School of Public Health, Guangzhou Medical University, Guangzhou 510182, People's Republic of China
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24
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Pogribny IP, James SJ, Beland FA. Molecular alterations in hepatocarcinogenesis induced by dietary methyl deficiency. Mol Nutr Food Res 2011; 56:116-25. [DOI: 10.1002/mnfr.201100524] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 08/23/2011] [Accepted: 09/07/2011] [Indexed: 01/12/2023]
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Tao MH, Mason JB, Marian C, McCann SE, Platek ME, Millen A, Ambrosone C, Edge SB, Krishnan SS, Trevisan M, Shields PG, Freudenheim JL. Promoter methylation of E-cadherin, p16, and RAR-β(2) genes in breast tumors and dietary intake of nutrients important in one-carbon metabolism. Nutr Cancer 2011; 63:1143-50. [PMID: 21916701 DOI: 10.1080/01635581.2011.605982] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Aberrant DNA methylation plays a critical role in carcinogenesis, and the availability of dietary factors involved in 1-carbon metabolism may contribute to aberrant DNA methylation. We investigated the association of intake of folate, vitamins B(2), B(6), B(12), and methionine with promoter methylation of E-cadherin, p16, and RAR-β(2) genes in archived tumor tissues from incident, primary breast cancer cases in a population-based case-control study. Real-time methylation-specific PCR was performed on 803 paraffin-embedded samples; usual dietary intake was queried from a food frequency questionnaire. Unconditional logistic regression was used to derive adjusted odds ratios and 95% confidence intervals for likelihood of promoter methylation for high compared to low intake of those 1-carbon nutrients. Overall, in case-case comparisons, dietary intakes of folate, vitamins B(2), B(6), B(12), and methionine were not associated with likelihood of promoter methylation of E- cadherin, p16, and RAR-β(2) for all cases combined or within strata defined by menopausal status and estrogen receptor status in this study. This finding, however, does not exclude the possibility that intake of such nutrients might have the ability to modulate promoter methylation in normal or premalignant (dysplastic) breast tissue.
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Affiliation(s)
- Meng-Hua Tao
- Department of Social and Preventive Medicine, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York 14214, USA.
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Wani NA, Kaur J. Reduced levels of folate transporters (PCFT and RFC) in membrane lipid rafts result in colonic folate malabsorption in chronic alcoholism. J Cell Physiol 2011; 226:579-87. [PMID: 21069807 DOI: 10.1002/jcp.22525] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We studied the effect of chronic ethanol ingestion on folate transport across the colonic apical membranes (CAM) in rats. Male Wistar rats were fed 1 g/kg body weight/day ethanol (20%) solution orally for 3 months and folate transport was studied in the isolated colon apical membrane vesicles. The folate transport was found to be carrier mediated, saturable, with pH optima at 5.0. Chronic ethanol ingestion reduced the folate transport across the CAM by decreasing the affinity of transporters (high Km) for the substrate and by decreasing the number of transporter molecules (low Vmax) on the colon luminal surface. The decreased transport activity at the CAM was associated with down-regulation of the proton-coupled folate transporter (PCFT) and the reduced folate carrier (RFC) which resulted in decreased PCFT and RFC protein levels in the colon of rats fed alcohol chronically. Moreover, the PCFT and the RFC were found to be distributed in detergent insoluble fraction of the CAM in rats. Floatation experiments on Optiprep density gradients demonstrated the association of the PCFT and the RFC protein with lipid rafts (LR). Chronic alcoholism decreased the PCFT and the RFC protein levels in the CAM LR in accordance with the decreased synthesis. Hence, we propose that downregulation in the expression of the PCFT and the RFC in colon results in reduced levels of these transporters in colon apical membrane LR as a mechanism of folate malabsorption during chronic alcoholism.
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Affiliation(s)
- Nissar Ahmad Wani
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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27
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5-Aza-2'-deoxycytidine stress response and apoptosis in prostate cancer. Clin Epigenetics 2011; 2:339-48. [PMID: 22704346 PMCID: PMC3365594 DOI: 10.1007/s13148-010-0019-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2010] [Accepted: 12/15/2010] [Indexed: 12/31/2022] Open
Abstract
While studying on epigenetic regulatory mechanisms (DNA methylation at C-5 of -CpG- cytosine and demethylation of methylated DNA) of certain genes (FAS, CLU, E-cadh, CD44, and Cav-1) associated with prostate cancer development and its better management, we noticed that the used in vivo dose of 5-aza-2'-deoxycytidine (5.0 to 10.0 nM, sufficient to inhibit DNA methyltransferase activity in vitro) helped in the transcription of various genes with known (steroid receptors, AR and ER; ER variants, CD44, CDH1, BRCA1, TGFβR1, MMP3, MMP9, and UPA) and unknown (DAZ and Y-chromosome specific) proteins and the respective cells remained healthy in culture. At a moderate dose (20 to 200 nM) of the inhibitor, cells remain growth arrested. Upon subsequent challenge with increased dose (0.5 to 5.0 μM) of the inhibitor, we observed that the cellular morphology was changing and led to death of the cells with progress of time. Analyses of DNA and anti-, pro-, and apoptotic factors of the affected cells revealed that the molecular events that went on are characteristics of programmed cell death (apoptosis).
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Abstract
Endometrial cancer is the most commonly diagnosed gynecological cancer, and it has been shown to be a complex disease driven by abnormal genetic, and epigenetic alterations, as well as environmental factors. Epigenetic changes resulting in aberrant gene expression are dynamic and modifiable features of many cancer types. A significant epigenetic change is aberrant DNA methylation. In this review, we review evidence on the role of aberrant DNA methylation, examining changes in relation to endometrial carcinogenesis, and report on recent advances in the understanding of the contribution of aberrant DNA methylation to endometrial cancer with the emphasis on the role of dietary/ lifestyle and environmental factors, as well as opportunities and challenges of DNA methylation in endometrial cancer management and prevention.
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Affiliation(s)
- Meng Hua Tao
- Department of Social and Preventive Medicine; School of Public Health and Health Professions; University at Buffalo, NY, USA.
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Wild L, Flanagan JM. Genome-wide hypomethylation in cancer may be a passive consequence of transformation. Biochim Biophys Acta Rev Cancer 2010; 1806:50-7. [PMID: 20398739 DOI: 10.1016/j.bbcan.2010.03.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 03/30/2010] [Indexed: 12/31/2022]
Abstract
Epigenetics describes the study of stable, reversible alterations to the genome that affect gene expression and genome function, the most studied mechanisms are DNA methylation and histone modifications. Over recent years there has been rapid progress to elucidate the nature and role of the mechanisms involved in promoter hypermethylation during carcinogenesis, however, the mechanism behind one of the earliest epigenetic observations in cancer, genome-wide hypomethylation, remains unclear. Current evidence is divided between the hypotheses that hypomethylation is either an important early cancer-causing aberration or that it is a passive inconsequential side effect of carcinogenesis. With recent discoveries of gene-body methylation, fast cyclic methylation of hormone dependent genes and candidate proteins involved in DNA demethylation elucidation of the role of hypomethylation and the mechanism behind it appears ever closer. With the burgeoning use of DNA methyltransferase inhibitors as a cancer therapy there is an increased need to understand the mechanisms and importance of genome-wide hypomethylation in cancer. This review will discuss the timing and potential causes of genomic hypomethylation during carcinogenesis and will propose a way forward to understand the underlying mechanisms.
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Abstract
Our spirits may be regulated by the methylation of our genes. Methylation, acetylation, and other biochemical processes are the molecular switches for turning genes on and off. There is evidence now that certain behaviors, feelings, and psychiatric symptoms may be modified by turning various genes on or off. If classical genetics is the sequence of DNA that is inherited, then epigenetics is a parallel process determining whether a given gene (ie, a sequence of DNA coding for transcription) is expressed into its RNA or is silenced. Epigenetics is now entering psychiatry with the hypothesis that normal genes as well as risk genes can both contribute to a mental disorder. That is, it has long been hypothesized that when “abnormal” genes with an altered sequence of DNA are inherited as risk genes for a mental illness, these risk genes will make an abnormal gene product in neurons, contributing to inefficient information processing in various brain circuits and creating risk for developing a symptom of a mental illness. Now comes the role of epigenetic actions in mental illnesses.
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Bistulfi G, Vandette E, Matsui SI, Smiraglia DJ. Mild folate deficiency induces genetic and epigenetic instability and phenotype changes in prostate cancer cells. BMC Biol 2010; 8:6. [PMID: 20092614 PMCID: PMC2845099 DOI: 10.1186/1741-7007-8-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 01/21/2010] [Indexed: 01/02/2023] Open
Abstract
Background Folate (vitamin B9) is essential for cellular proliferation as it is involved in the biosynthesis of deoxythymidine monophosphate (dTMP) and s-adenosylmethionine (AdoMet). The link between folate depletion and the genesis and progression of cancers of epithelial origin is of high clinical relevance, but still unclear. We recently demonstrated that sensitivity to low folate availability is affected by the rate of polyamine biosynthesis, which is prominent in prostate cells. We, therefore, hypothesized that prostate cells might be highly susceptible to genetic, epigenetic and phenotypic changes consequent to folate restriction. Results We studied the consequences of long-term, mild folate depletion in a model comprised of three syngenic cell lines derived from the transgenic adenoma of the mouse prostate (TRAMP) model, recapitulating different stages of prostate cancer; benign, transformed and metastatic. High-performance liquid chromatography analysis demonstrated that mild folate depletion (100 nM) sufficed to induce imbalance in both the nucleotide and AdoMet pools in all prostate cell lines. Random oligonucleotide-primed synthesis (ROPS) revealed a significant increase in uracil misincorporation and DNA single strand breaks, while spectral karyotype analysis (SKY) identified five novel chromosomal rearrangements in cells grown with mild folate depletion. Using global approaches, we identified an increase in CpG island and histone methylation upon folate depletion despite unchanged levels of total 5-methylcytosine, indicating a broad effect of folate depletion on epigenetic regulation. These genomic changes coincided with phenotype changes in the prostate cells including increased anchorage-independent growth and reduced sensitivity to folate depletion. Conclusions This study demonstrates that prostate cells are highly susceptible to genetic and epigenetic changes consequent to mild folate depletion as compared to cells grown with supraphysiological amounts of folate (2 μM) routinely used in tissue culture. In addition, we elucidate for the first time the contribution of these aspects to consequent phenotype changes in epithelial cells. These results provide a strong rationale for studying the effects of folate manipulation on the prostate in vivo, where cells might be more sensitive to changes in folate status resulting from folate supplementation or antifolate therapeutic approaches.
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Affiliation(s)
- Gaia Bistulfi
- Department of Cancer Genetics, Roswell Park Cancer Institute, Elm & Carlton Streets, BLSC L3-314, Buffalo, NY 14263, USA.
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Deng D, Liu Z, Du Y. Epigenetic alterations as cancer diagnostic, prognostic, and predictive biomarkers. ADVANCES IN GENETICS 2010; 71:125-76. [PMID: 20933128 DOI: 10.1016/b978-0-12-380864-6.00005-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alterations of DNA methylation and transcription of microRNAs (miRNAs) are very stable phenomena in tissues and body fluids and suitable for sensitive detection. These advantages enable us to translate some important discoveries on epigenetic oncology into biomarkers for control of cancer. A few promising epigenetic biomarkers are emerging. Clinical trials using methylated CpG islands of p16, Septin9, and MGMT as biomarkers are carried out for predication of cancer development, diagnosis, and chemosensitivity. Circulating miRNAs are promising biomarkers, too. Breakthroughs in the past decade imply that epigenetic biomarkers may be useful in reducing the burden of cancer.
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Affiliation(s)
- Dajun Deng
- Key Laboratory of Carcinogenesis and Translational Research (Ministry ofEducation), Peking University School of Oncology, Beijing Cancer Hospitaland Institute, Fu-Cheng-Lu, Haidian District, Beijing, 100142, PR China
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Besplug J, Burke P, Ponton A, Filkowski J, Titov V, Kovalchuk I, Kovalchuk O. Sex and tissue-specific differences in low-dose radiation-induced oncogenic signaling. Int J Radiat Biol 2009; 81:157-68. [PMID: 16019925 DOI: 10.1080/09553000500103512] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE The possible adverse health effects of low-dose radiation (LDR) exposure constitute a growing concern. Clinically and environmentally relevant exposures occur predominantly under chronic conditions, notwithstanding that most studies of LDR effects have been performed using a single acute exposure. Sex- and tissue-specificity of the LDR-induced changes have not been considered before. We investigated LDR-related expression patterns in muscle, liver and spleen of male and female mice subjected to acute and chronic LDR exposure. Genes involved in oncogenic signaling were of specific interest, as radiation is a well-known carcinogen. MATERIALS AND METHODS We analyzed the expression pattern of genes coding for growth factors and growth-factor receptors, cytoplasmic serine/threonine protein kinases, G-proteins and nuclear DNA-binding proteins, and other important components of oncogenic signaling. RESULTS We found sex- and tissue-specific changes in the expression of Ras superfamily members (Nras, Rab2, Rab34, Vav2), protein kinase C (PKC) isoforms (PKCbeta, PKCmu), AP-1 factor components (Jun, JunB and FosB), Wnt signaling pathway members as well as in a variety of other cellular proto-oncogenes and oncogenes. Importantly, Western blot analysis of JunB, PKCmu and Rab2 proteins supported the transcriptomic data. CONCLUSIONS Substantially different protein levels were observed in all three tissues (muscle, spleen and liver) of acutely and chronically irradiated female and male animals. Based on the obtained data and available literature, we discuss several possible mechanisms that may contribute to radiation-induced carcinogenesis in various tissues of males and females. From our results we could identify the genes that may serve as sex- and tissue-specific biomarkers of the LDR exposure.
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Affiliation(s)
- Jill Besplug
- Department of Biological Sciences, University of Lethbridge, Alberta, Canada
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Tryndyak VP, Ross SA, Beland FA, Pogribny IP. Down-regulation of the microRNAs miR-34a, miR-127, and miR-200b in rat liver during hepatocarcinogenesis induced by a methyl-deficient diet. Mol Carcinog 2009; 48:479-87. [PMID: 18942116 DOI: 10.1002/mc.20484] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Altered expression of microRNAs (miRNAs) has been reported in diverse human cancers; however, the down-regulation or up-regulation of any particular miRNAs in cancer is not sufficient to address the role of these changes in carcinogenesis. In this study, using the rat model of liver carcinogenesis induced by a methyl-deficient diet, which is relevant to the hepatocarcinogenesis in humans associated with viral hepatitis C and B infections, alcohol exposure and metabolic liver diseases, we showed that the development of hepatocellular carcinoma (HCC) is characterized by prominent early changes in expression of miRNA genes, specifically by inhibition of expression of microRNAs miR-34a, miR-127, miR-200b, and miR-16a involved in the regulation of apoptosis, cell proliferation, cell-to-cell connection, and epithelial-mesenchymal transition. The mechanistic link between these alterations in miRNAs expression and the development of HCC was confirmed by the corresponding changes in the levels of E2F3, NOTCH1, BCL6, ZFHX1B, and BCL2 proteins targeted by these miRNAs. The significance of miRNAs expression dysregulation in respect to hepatocarcinogenesis was confirmed by the persistence of these miRNAs alterations in the livers of methyl-deficient rats re-fed a methyl-adequate diet. Altogether, the early occurrence of alterations in miRNAs expression and their persistence during the entire process of hepatocarcinogenesis indicate that the dysregulation of microRNAs expression may be an important contributing factor in the development of HCC.
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Affiliation(s)
- Volodymyr P Tryndyak
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079, USA
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Hamid A, Wani NA, Kaur J. New perspectives on folate transport in relation to alcoholism-induced folate malabsorption--association with epigenome stability and cancer development. FEBS J 2009; 276:2175-91. [PMID: 19292860 DOI: 10.1111/j.1742-4658.2009.06959.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Folates are members of the B-class of vitamins, which are required for the synthesis of purines and pyrimidines, and for the methylation of essential biological substances, including phospholipids, DNA, and neurotransmitters. Folates cannot be synthesized de novo by mammals; hence, an efficient intestinal absorption process is required. Intestinal folate transport is carrier-mediated, pH-dependent and electroneutral, with similar affinity for oxidized and reduced folic acid derivatives. The various transporters, i.e. reduced folate carrier, proton-coupled folate transporter, folate-binding protein, and organic anion transporters, are involved in the folate transport process in various tissues. Any impairment in uptake of folate can lead to a state of folate deficiency, the most prevalent vitamin deficiency in world, affecting 10% of the population in the USA. Such impairments in folate transport occur in a variety of conditions, including chronic use of ethanol, some inborn hereditary disorders, and certain diseases. Among these, ethanol ingestion has been the major contributor to folate deficiency. Ethanol-associated folate deficiency can develop because of dietary inadequacy, intestinal malabsorption, altered hepatobiliary metabolism, enhanced colonic metabolism, and increased renal excretion. Ethanol reduces the intestinal and renal uptake of folate by altering the binding and transport kinetics of folate transport systems. Also, ethanol reduces the expression of folate transporters in both intestine and kidney, and this might be a contributing factor for folate malabsorption, leading to folate deficiency. The maintenance of intracellular folate homeostasis is essential for the one-carbon transfer reactions necessary for DNA synthesis and biological methylation reactions. DNA methylation is an important epigenetic determinant in gene expression, in the maintenance of DNA integrity and stability, in chromosomal modifications, and in the development of mutations. Ethanol, a toxin that is consumed regularly, has been found to affect the methylation of DNA. In addition to its effect on DNA methylation due to folate deficiency, ethanol could directly exert its effect through its interaction with one-carbon metabolism, impairment of methyl group synthesis, and affecting the enzymes regulating the synthesis of S-adenosylmethionine, the primary methyl group donor for most biological methylation reactions. Thus, ethanol plays an important role in the pathogenesis of several diseases through its potential ability to modulate the methylation of biological molecules. This review discusses the underlying mechanism of folate malabsorption in alcoholism, the mechanism of methylation-associated silencing of genes, and how the interaction between ethanol and folate deficiency affects the methylation of genes, thereby modulating epigenome stability and the risk of cancer.
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Affiliation(s)
- Abid Hamid
- Department of Biochemistry, Postgraduate Institute of Medical Education and Research Chandigarh, India
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Dobosy JR, Fu VX, Desotelle JA, Srinivasan R, Kenowski ML, Almassi N, Weindruch R, Svaren J, Jarrard DF. A methyl-deficient diet modifies histone methylation and alters Igf2 and H19 repression in the prostate. Prostate 2008; 68:1187-95. [PMID: 18459101 DOI: 10.1002/pros.20782] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Folate and methyl-group deficiency has been linked to prostate cancer susceptibility, yet the mechanisms underlying these observations are incompletely understood. The region of the genome containing the imprinted genes insulin-like growth factor 2 (Igf2) and H19, both of which display oncogenic functions, may be particularly sensitive to environmental influences. METHODS To determine whether a methyl-deficient diet impacts epigenetic controls at the Igf2-H19 locus, we placed C57BL/6 mice containing a polymorphism at the imprinted Igf2-H19 locus on a choline and methionine deficient (CMD) diet. We interrogated this locus for expression and epigenetic changes in prostate tissues. RESULTS A significant increase in both Igf2 and H19 expression was found in CMD prostate tissues compared to controls. These expression changes were reversible with shorter exposure to the CMD diet. Chromatin immunoprecipitation (ChIP) revealed significant decreases in repressive histone modifications (dimethyl-H3K9) within the H19 promoter, as well as Igf2 P2 and P3 promoters. DNA methylation within these promoters was not altered. No significant change in Igf2 or H19 imprinting was observed. CONCLUSIONS These findings highlight the plasticity of the epigenome in an epithelial organ vulnerable to neoplastic change. They further suggest that chromatin modifications are more susceptible to methyl-deficient diets than DNA methylation at this locus.
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Affiliation(s)
- Joseph R Dobosy
- Environmental and Molecular Toxicology, University of Wisconsin, Madison, Wisconsin 53792, USA
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Buda G, Orciuolo E, Maggini V, Petrini M. Folic acid fortification and cancer risk. Lancet 2008; 371:1336. [PMID: 18424322 DOI: 10.1016/s0140-6736(08)60592-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Abstract
Acromegaly is characterized by sustained elevation of circulating growth hormone (GH) and insulin-like growth factor I (IGF-I), and is clearly associated with increased morbidity and overall mortality mainly due to cardiovascular, metabolic, and respiratory diseases. Although cancer-related mortality varies widely amongst retroperspective studies, it appears to be consistently elevated mainly in patients with uncontrolled disease. We review individual tumor types including neoplasms of the colon, breast, prostate, and thyroid where in vitro, animal studies, and studies in non-acromegalic cancer patients have established a role for the GH/IGF-I axis in tumor progression and possibly initiation. We highlight deficiencies in data in acromegalic patients where the evidence is less convincing. Instead, we explore the hypothesis that acromegaly, independent of hormone secretion, is a disease that heralds genetic and/or epigenetic alterations predisposing to cancer risk elsewhere.
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Affiliation(s)
- Siobhan Loeper
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
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Jiang G, Xu L, Song S, Zhu C, Wu Q, Zhang L, Wu L. Effects of long-term low-dose cadmium exposure on genomic DNA methylation in human embryo lung fibroblast cells. Toxicology 2008; 244:49-55. [PMID: 18077075 DOI: 10.1016/j.tox.2007.10.028] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Revised: 10/26/2007] [Accepted: 10/28/2007] [Indexed: 11/25/2022]
Abstract
Cadmium is a toxic transition metal of continuing occupational and environmental concern. As a well-recognized human carcinogen, its carcinogenic mechanisms are still poorly understood. Cadmium has long been considered a non-genotoxic carcinogen and thought to act through epigenetic mechanisms. In the present study, we tested the effects of long-term low-dose cadmium exposure on DNA methylation in human embryo lung fibroblast (HLF) cells. After 2 months of exposure to 0-1.5 micromol/L cadmium, both the level of genomic DNA methylation and the enzyme activity of DNA methyltransferases (DNMTs) were increased in a concentration-related manner. Moreover, our results showed that cadmium exposure up-regulated the mRNA levels of DNMT1, DNMT3a and DNMT3b at higher concentrations. We further tested the growth dynamics of HLF cells, and observed significantly elevated growth rates, decreased cell population of G0/G1-phase and increased cell population of S-phase at 0.9, 1.2, and 1.5 micromol/L concentrations. Our study indicated that long-term low-dose cadmium exposure could disrupt DNA methylation, which may be one of the possible underlying carcinogenic mechanisms of cadmium.
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Affiliation(s)
- Gaofeng Jiang
- Faculty of Preventive Medicine, Medical College, Wuhan University of Science and Technology, Huangjiahu Campus, Wuhan 430065, Hubei Province, People's Republic of China.
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Pogribny IP, Rusyn I, Beland FA. Epigenetic aspects of genotoxic and non-genotoxic hepatocarcinogenesis: studies in rodents. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2008; 49:9-15. [PMID: 17879298 PMCID: PMC2705440 DOI: 10.1002/em.20342] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Hepatocellular carcinoma, which is one of the most prevalent life-threatening human cancers, is showing an increased incidence worldwide. Recent evidence indicates that the development of hepatocellular carcinoma is associated with not only genetic alterations, but also with profound epigenetic changes. This review summarizes the current knowledge about epigenetic alterations during rodent hepatocarcinogenesis, considers the similarities and differences in epigenetic effects of genotoxic and non-genotoxic rodent liver carcinogens, and discusses the possible role of these effects in the causality of liver tumor development.
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Affiliation(s)
- Igor P Pogribny
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079, USA.
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Aberrant p16 promoter methylation among Greek lung cancer patients and smokers: correlation with smoking. Eur J Cancer Prev 2007; 16:396-402. [PMID: 17923809 DOI: 10.1097/01.cej.0000236260.26265.d6] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Genetic and environmental factors (dietary and smoking) influence lung cancer epidemiology and induce epigenetic modifications that should be assessed in individual populations. We analyzed p16 methylation among Greek non-small cell lung carcinoma patients and smokers using two-stage methylation-specific polymerase chain reaction. One hundred and fifty specimens from cancerous and adjacent non-cancerous tissue, bronchial washings and sputum from patients and 48 specimens, mostly sputum, from disease-free smokers were included. p16 methylation was very frequent in biopsies (82.85%) and bronchial washings (non-small cell lung carcinoma, 80.35%; small cell lung carcinoma, 16.66%) from patients, but also in adjacent non-cancerous tissue (45.71%). Concordance of p16 methylation and positivity by cytological examination was 51.78%. Methylation was also observed in sputum from asymptomatic cytology-negative smokers (22.5%) and chronic obstructive pulmonary disease patients (three of eight). Among disease-free individuals, methylation correlated only with heavy smoking (>50 pack-years, P<0.001) and differed among male and female disease-free smokers. In summary, p16 methylation is very frequent among non-small cell lung carcinoma patients, and correlates with heavy cigarette consumption only in disease-free smokers.
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Environment, diet and CpG island methylation: epigenetic signals in gastrointestinal neoplasia. Food Chem Toxicol 2007; 46:1346-59. [PMID: 17976883 DOI: 10.1016/j.fct.2007.09.101] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 09/14/2007] [Accepted: 09/19/2007] [Indexed: 12/26/2022]
Abstract
The epithelial surfaces of the mammalian alimentary tract are characterised by very high rates of cell proliferation and DNA synthesis, and in humans they are highly susceptible to cancer. The role of somatic mutations as drivers of carcinogenesis in the alimentary tract is well established, but the importance of gene silencing by epigenetic mechanisms is increasingly recognised. Methylation of CpG islands is an important component of the epigenetic code that regulates gene expression during development and normal cellular differentiation, and a number of genes are well known to become abnormally methylated during the development of tumours of the oesophagus, stomach and colorectum. Aberrant patterns of DNA methylation develop as a result of pathological processes such as chronic inflammation, and in response to various dietary factors, including imbalances in the supply of methyl donors, particularly folates, and exposure to DNA methyltransferase inhibitors, which include polyphenols and possibly isothiocyanates from plant foods. However the importance of these environmental interactions in human health and disease remains to be established. Recent moves to modify the exposure of human populations to folate, by mandatory supplementation of cereal foods, emphasise the importance of understanding the susceptibility of the human epigenome to dietary and other environmental effects.
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Shimizu K, Onishi M, Sugata E, Sokuza Y, Mori C, Nishikawa T, Honoki K, Tsujiuchi T. Disturbance of DNA methylation patterns in the early phase of hepatocarcinogenesis induced by a choline-deficient L-amino acid-defined diet in rats. Cancer Sci 2007; 98:1318-22. [PMID: 17640295 PMCID: PMC11158837 DOI: 10.1111/j.1349-7006.2007.00564.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The authors investigated the DNA methylation patterns of the E-cadherin, Connexin 26 (Cx26), Rassf1a and c-fos genes in the early phase of rat hepatocarcinogenesis induced by a choline-deficient L-amino acid-defined (CDAA) diet. Six-week-old F344 male rats were continuously fed with the CDAA diet, and three animals were then killed at each of 4 and 8 days and 3 weeks. Genomic DNA was extracted from livers for assessment of methylation status in the 5' upstream regions of E-cadherin, Cx26, Rassf1a and c-fos genes by bisulfite sequencing, compared with normal livers. The livers of rats fed the CDAA diet for 4 and 8 days and 3 weeks were methylated in E-cadherin, Cx26 and Rassf1a genes, while normal livers were all unmethylated. In contrast, normal livers were highly methylated in c-fos gene. Although the livers at 4 days were weakly methylated, those at 8 days and 3 weeks were markedly unmethylated. Methylation patterns of CpG sites in E-cadherin, Cx26 and Rassf1a were sparse and the methylation was not associated with gene repression. These results indicate that gene-specific DNA methylation patterns were found in livers of rats after short-term feeding of the CDAA diet, suggesting gene-specific hypermethylation might be involved in the early phase of rat hepatocarcinogenesis induced by the CDAA diet.
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Affiliation(s)
- Kyoko Shimizu
- Laboratory of Cancer Biology and Bioinformatics, Department of Life Science, Faculty of Science and Engineering, Kinki University, 3-4-1 Kowakae, Higashiosaka, Osaka 577-8502, Japan
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Hsiung DT, Marsit CJ, Houseman EA, Eddy K, Furniss CS, McClean MD, Kelsey KT. Global DNA methylation level in whole blood as a biomarker in head and neck squamous cell carcinoma. Cancer Epidemiol Biomarkers Prev 2007; 16:108-14. [PMID: 17220338 DOI: 10.1158/1055-9965.epi-06-0636] [Citation(s) in RCA: 239] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Head and neck squamous cell carcinoma (HNSCC) is commonly associated with tobacco and alcohol exposures, although dietary factors, particularly folate, and human papillomavirus, are also risk factors. Epigenetic alterations are increasingly implicated in the initiation and progression of cancer. Genome-wide (global) hypomethylation seems to occur in early neoplasia and is a feature of genomic DNA derived from solid tumor tissues, including HNSCC. This study aimed to determine whether global methylation in DNA derived from whole blood, a proxy tissue, is associated with HNSCC and to assess potential modification of this property by environmental or behavioral risk factors. METHODS Global DNA methylation levels were assessed using a modified version of the combined bisulfite restriction analysis of the LRE1 sequence in a population-based case-control study of HNSCC from the Boston area. RESULTS Hypomethylation lead to a significant 1.6-fold increased risk for disease (95% confidence interval, 1.1-2.4), in models controlled for other HNSCC risk factors. Smoking showed a significant differential effect (P < 0.03) on blood relative methylation between cases and controls. Furthermore, in cases, variant genotype in the MTHFR gene and low folate intake showed relationships with decreased global methylation, whereas in controls, antibody response to human papillomavirus 16 was associated with an increased global methylation level. DISCUSSION DNA hypomethylation in nontarget tissue was independently associated with HNSCC and had a complex relationship with the known risk factors associated with the genesis of HNSCC.
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Affiliation(s)
- Debra Ting Hsiung
- Department of Genetics and Complex Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA
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Tsujiuchi T, Shimizu K, Itsuzaki Y, Onishi M, Sugata E, Fujii H, Honoki K. CpG site hypermethylation of E-cadherin and Connexin26 genes in hepatocellular carcinomas induced by a choline-deficient L-Amino Acid-defined diet in rats. Mol Carcinog 2007; 46:269-74. [PMID: 17295234 DOI: 10.1002/mc.20268] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We investigated DNA methylation patterns of E-cadherin and Connexin26 (Cx26) genes in rat hepatocellular carcinomas (HCCs) induced by a choline-deficient L-Amino Acid-defined (CDAA) diet. Six-wks-old F344 male rats were continuously fed with a CDAA diet for 75 wks, and were then killed. A total of five HCCs were obtained, and genomic DNA was extracted from each HCC for assessment of methylation status in the 5' upstream regions of E-cadherin and Cx26 genes by bisulfite sequencing, comparing to two normal liver tissues. The five HCCs showed highly methylated E-cadherin and Cx26 genes, while these genes in two normal liver tissues were all unmethylated. For analysis of gene expression, real-time quantitative reverse transcription (RT)-polymerase chain reaction (PCR) was performed. Expressions of E-cadherin and Cx26 genes were significantly reduced in the five HCCs (P < 0.0001 and P < 0.001, respectively) compared to normal liver tissues, correlating with their methylation statuses. These results suggested that hypermethylation of E-cadherin and Cx26 genes may be involved in the development of HCCs induced by a CDAA diet in rats.
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Affiliation(s)
- Toshifumi Tsujiuchi
- Laboratory of Cancer Biology and Bioinformatics, Department of Life Science, Faculty of Science and Engineering, Kinki University, Higashiosaka, Osaka, Japan
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Park IY, Sohn BH, Yu E, Suh DJ, Chung YH, Lee JH, Surzycki SJ, Lee YI. Aberrant epigenetic modifications in hepatocarcinogenesis induced by hepatitis B virus X protein. Gastroenterology 2007; 132:1476-94. [PMID: 17408664 DOI: 10.1053/j.gastro.2007.01.034] [Citation(s) in RCA: 227] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Accepted: 12/14/2006] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS The involvement of the hepatitis B virus X (HBx) protein in epigenetic modifications during hepatocarcinogenesis has not been previously characterized. The aim of the present study was to identify the involvement of HBx in regional hypermethylation and global hypomethylation during the formation of hepatocellular carcinoma (HCC). METHODS Liver cell lines were transiently or stably transfected with an HBx-expressing vector. DNA methyltransferase (DNMT) promoter activity changes were examined by luciferase assay and chromatin immunoprecipitation. The methylation status of insulin-like growth factor binding protein-3 was examined by methyl-specific polymerase chain reaction and bisulfite sequencing. Global DNA methylation levels were examined using 5-methylcytosine dot blot and methylation-sensitive Southern blot analysis. HBx-mediated DNA methylation abnormalities were confirmed in patient HCC samples using methyl-specific polymerase chain reaction and 5-methylcytosine dot blot analysis. RESULTS HBx expression increased total DNMT activities by up-regulation of DNMT1, DNMT3A1, and DNMT3A2 and selectively promoted regional hypermethylation of specific tumor suppressor genes. HBx specifically repressed insulin-like growth factor-3 expression through de novo methylation via DNMT3A1 and DNMT3A2 and by inhibiting SP1 binding via recruiting methyl CpG binding protein 2 to the newly methylated SP1 binding element. HBx also induced global hypomethylation of satellite 2 repeat sequences by down-regulating DNMT3B. The prevalence of these specific methylation abnormalities by HBx was significantly correlated with HBx expression in HBV-infected HCC patients. CONCLUSIONS Targeted deregulation of DNMTs by HBx promotes both specific regional hypermethylation and global hypomethylation. These epigenetic modulations by HBx may suggest a mechanism for epigenetic tumorigenesis during HBV-mediated hepatocarcinogenesis.
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Affiliation(s)
- In Young Park
- Liver Cell Signal Transduction Laboratory, Molecular Cancer Research Center, KRIBB, Daejeon, Korea
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Buda G, Maggini V, Galimberti S, Barale R, Rossi AM, Petrini M. Folate levels and methylation of CDKI proteins. Leuk Res 2007; 31:569-70. [PMID: 17118446 DOI: 10.1016/j.leukres.2006.10.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2006] [Revised: 10/15/2006] [Accepted: 10/19/2006] [Indexed: 11/29/2022]
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Katula KS, Heinloth AN, Paules RS. Folate deficiency in normal human fibroblasts leads to altered expression of genes primarily linked to cell signaling, the cytoskeleton and extracellular matrix. J Nutr Biochem 2007; 18:541-52. [PMID: 17320366 DOI: 10.1016/j.jnutbio.2006.11.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Revised: 11/06/2006] [Accepted: 11/22/2006] [Indexed: 11/22/2022]
Abstract
The molecular basis linking folate deficiency to certain health conditions and developmental defects is not fully understood. We examined the consequences of folate deficiency on global gene expression by microarray and compared transcript levels in normal human fibroblast cells (GM03349) grown in folate-deficient and -sufficient medium. The largest represented groups from the selected genes functioned in cell signaling, the cytoskeleton and the extracellular matrix and included the Wnt pathway genes DKK1, WISP1 and WNT5A. Twelve selected genes were further validated by qRT-PCR. Analysis of six genes at 4, 7, 10 and 14 days indicated that the relative differences in transcript levels between folate-sufficient and -deficient cells increases with time. Transcripts for 7 of the 12 selected genes were detected in the human lymphoblast cell line GM02257, and of these, changes in 4 genes corresponded to the results with fibroblast cells. Fibroblast cells were treated with the compounds homocysteine, methotrexate and the MEK1/2 inhibitor U0126, and relative transcript levels of six genes were determined. U0126 caused changes that more closely mimicked those detected in folate-deficient cells. The response of the DKK1 and TAGLN gene promoters to folate deficiency and compounds was examined in NIH3T3 cells using luciferase reporter plasmids. Promoter activity for both genes was decreased by folate deficiency and methotrexate and unaffected by homocysteine. U0126 caused a decrease in DKK1 promoter activity at 50 microM and had no effect on TAGLN promoter activity. These findings suggest an alternative mechanism for how folate deficiency leads to changes in gene expression and altered cell function.
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Affiliation(s)
- Karen S Katula
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
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Catal F, Avci A, Karadag A, Alioglu B, Avci Z. Oxidant and antioxidant status of Turkish marasmic children: a single center study. J Trace Elem Med Biol 2007; 21:108-12. [PMID: 17499150 DOI: 10.1016/j.jtemb.2007.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2006] [Accepted: 01/26/2007] [Indexed: 10/23/2022]
Abstract
The aim of this study was to investigate plasma oxidant and antioxidant status in Turkish marasmic children. The study population consisted of 38 marasmic children (group I) and 28 age-matched children (group II) who were apparently well, with weight-forage >80% of the standards in the same region. After overnight fasting, venous blood samples were drawn and immediately transferred to heparinized and normal tubes. Plasma antioxidant potential (AOP), and malondialdehyde (MDA) levels were measured in both groups. The plasma MDA levels were found to be higher in group I than in group II. However, plasma AOP values were lower in group I than in group II. The present study suggests that AOP is reduced due to an impaired antioxidant system in the plasma of malnourished patients. This oxidant stress causes significant peroxidation. Also, the antioxidant defense system of the patients is deteriorated in marasmus.
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Affiliation(s)
- Ferhat Catal
- Department of Pediatrics, Fatih University School of Medicine, Ankara, Turkey
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Pogribny IP, Tryndyak VP, Muskhelishvili L, Rusyn I, Ross SA. Methyl deficiency, alterations in global histone modifications, and carcinogenesis. J Nutr 2007; 137:216S-222S. [PMID: 17182829 DOI: 10.1093/jn/137.1.216s] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The methyl-deficient model of endogenous hepatocarcinogenesis in rodents is unique in that dietary omission rather than the addition of chemical carcinogens leads to tumor formation. Thus, the biochemical and molecular events predisposing to cancer in this model result from chronic metabolic stress and provide an ideal model system to study progressive alterations that occur during carcinogenesis. Moreover, epigenetic alterations imposed by this diet are believed to be 1 of the main mechanisms responsible for malignant transformation of rat liver cells. In this study we examined the changes in global histone modification patterns in liver during hepatocarcinogenesis induced by methyl deficiency. Feeding animals the methyl-deficient diet (MDD) led to progressive loss of histone H4 lysine 20 trimethylation (H4K20me3), H3 lysine 9 trimethylation (H3K9me3), and histone H3 lysine 9 (H3K9ac) and histone H4 lysine 16 (H4K16ac) acetylation. A considerable decrease of H4K20me3 and H3K9ac was also detected in liver tumors induced by MDD. In contrast, liver tumors displayed an increase in H3K9me3 and H4K16ac. To determine the possible mechanism of alterations of histone modifications, we analyzed the expression of histone-modifying enzymes in liver during hepatocarcinogenesis. The expression of Suv4-20h2 and RIZ1 histone methyltransferases (HMTs) steadily decreased along with the development of liver tumors and reached its lowest level in tumor tissue, whereas the expression of Suv39-h1 HMT and histone acetyltransferase 1 (HAT1) substantially increased in tumors. These results illustrate the complexity and importance of histone modification changes in the etiology of hepatocarcinogenesis induced by MDD.
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Affiliation(s)
- Igor P Pogribny
- National Center for Toxicological Research, Jefferson, AR 72079, USA.
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