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Shen PW, Ho CT, Hsiao SH, Chou YT, Chang YC, Liu JJ. Disruption of Cytosolic Folate Integrity Aggravates Resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors and Modulates Metastatic Properties in Non-Small-Cell Lung Cancer Cells. Int J Mol Sci 2021; 22:ijms22168838. [PMID: 34445544 PMCID: PMC8396212 DOI: 10.3390/ijms22168838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/29/2021] [Accepted: 08/13/2021] [Indexed: 01/04/2023] Open
Abstract
Patients with advanced-stage non-small-cell lung cancer (NSCLC) are susceptible to malnutrition and develop folate deficiency (FD). We previously found that folate deprivation induces drug resistance in hepatocellular carcinoma; here, we assessed whether disrupted cytoplasmic folate metabolism could mimic FD-induced metastasis and affect the sensitivity of NSCLC cells to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs). We examined whether cytosolic folate metabolism in NSCLC cells was disrupted by FD or the folate metabolism blocker pemetrexed for 1–4 weeks. Our results revealed an increase in NF-κB overexpression–mediated epithelial-mesenchymal transition biomarkers: N-cadherin, vimentin, matrix metalloproteinases (MMPs), SOX9, and SLUG. This finding suggests that the disruption of folate metabolism can drastically enhance the metastatic properties of NSCLC cells. Cytosolic FD also affected EGFR-TKI cytotoxicity toward NSCLC cells. Because SLUG and N-cadherin are resistance effectors against gefitinib, the effects of SLUG knockdown in folate antagonist–treated CL1-0 cells were evaluated. SLUG knockdown prevented SLUG/NF-κB/SOX9-mediated invasiveness and erlotinib resistance acquisition and significantly reduced pemetrexed-induced gelatinase activity and MMP gene expression. To summarize, our data reveal two unprecedented adverse effects of folate metabolism disruption in NSCLC cells. Thus, the folic acid status of patients with NSCLC under treatment can considerably influence their prognosis.
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Affiliation(s)
- Po-Wen Shen
- Program in Molecular Medicine, National Yang Ming Chiao Tung University and Academia Sinica, Taipei 112, Taiwan;
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan;
| | - Chun-Te Ho
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
| | - Shih-Hsin Hsiao
- Division of Pulmonary Medicine, Department of Internal Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan;
| | - Yu-Ting Chou
- Department of Life Science, National Tsing Hua University, Hsinchu 300, Taiwan;
| | - Yi-Cheng Chang
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan;
- Department of Internal Medicine, National Taiwan University Hospital, Taipei 110, Taiwan
- Graduate Institute of Medical Genomics and Proteomics, National Taiwan University, Taipei 110, Taiwan
| | - Jun-Jen Liu
- School of Medical Laboratory Science and Biotechnology, Taipei Medical University, Taipei 110, Taiwan
- Ph.D. Program in Medical Biotechnology, Taipei Medical University, Taipei 110, Taiwan
- Ph.D. Program in Biotechnology Research and Development, Taipei Medical University, Taipei 110, Taiwan
- Correspondence: ; Tel.: +886-2-27361661
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Canale M, Casadei-Gardini A, Ulivi P, Arechederra M, Berasain C, Lollini PL, Fernández-Barrena MG, Avila MA. Epigenetic Mechanisms in Gastric Cancer: Potential New Therapeutic Opportunities. Int J Mol Sci 2020; 21:E5500. [PMID: 32752096 PMCID: PMC7432799 DOI: 10.3390/ijms21155500] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/27/2020] [Accepted: 07/29/2020] [Indexed: 02/07/2023] Open
Abstract
Gastric cancer (GC) is one of the deadliest malignancies worldwide. Complex disease heterogeneity, late diagnosis, and suboptimal therapies result in the poor prognosis of patients. Besides genetic alterations and environmental factors, it has been demonstrated that alterations of the epigenetic machinery guide cancer onset and progression, representing a hallmark of gastric malignancies. Moreover, epigenetic mechanisms undergo an intricate crosstalk, and distinct epigenomic profiles can be shaped under different microenvironmental contexts. In this scenario, targeting epigenetic mechanisms could be an interesting therapeutic strategy to overcome gastric cancer heterogeneity, and the efforts conducted to date are delivering promising results. In this review, we summarize the key epigenetic events involved in gastric cancer development. We conclude with a discussion of new promising epigenetic strategies for gastric cancer treatment.
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Affiliation(s)
- Matteo Canale
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy; (M.C.); (P.U.)
| | - Andrea Casadei-Gardini
- Department of Oncology and Hematology, Division of Oncology, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Paola Ulivi
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, 47014 Meldola, Italy; (M.C.); (P.U.)
| | - Maria Arechederra
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; (M.A.); (C.B.); (M.G.F.-B.)
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
| | - Carmen Berasain
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; (M.A.); (C.B.); (M.G.F.-B.)
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
- National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, Carlos III Health Institute), 28029 Madrid, Spain
| | - Pier-Luigi Lollini
- Laboratory of Immunology and Biology of Metastasis, Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, 40126 Bologna, Italy;
| | - Maite G. Fernández-Barrena
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; (M.A.); (C.B.); (M.G.F.-B.)
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
- National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, Carlos III Health Institute), 28029 Madrid, Spain
| | - Matías A. Avila
- Program of Hepatology, Center for Applied Medical Research (CIMA), University of Navarra, 31008 Pamplona, Spain; (M.A.); (C.B.); (M.G.F.-B.)
- IdiSNA, Navarra Institute for Health Research, 31008 Pamplona, Spain
- National Institute for the Study of Liver and Gastrointestinal Diseases (CIBERehd, Carlos III Health Institute), 28029 Madrid, Spain
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Liew SC. Folic acid and diseases - supplement it or not? Rev Assoc Med Bras (1992) 2016; 62:90-100. [PMID: 27008500 DOI: 10.1590/1806-9282.62.01.90] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 05/31/2015] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION folic acid is a water soluble vitamin, which is synthetically-produced and found in fortified foods and supplements. Folate is found naturally in plants, such as the dark green leafy vegetables. Folate is not synthesized de novo by humans, therefore the daily requirements are met from the dietary intake of folic acid supplements or food rich in this vitamin. Folate deficiency could lead to numerous common health problems. Hyperhomocysteinemia and the possibility of malignancy developments are the long term consequences of this deficit albeit contradictory findings on these claims. METHODS the articles included in this review focused on recent updated evidence-based reports and meta-analyses on the associations of the serum folate/folic acid and the various diseases found globally. RESULTS the benefit of folic acid supplementation in the pre-conception period for the prevention of neural tube defects (NTDs) was well established and it was suggested that counseling sessions should be given to women with previous pregnancies affected by NTDs. However, supplementation of folic acid and its medicinal effects in the treatment of other diseases were contradictory and unclear. CONCLUSION more detailed investigations into the health benefits of folic acid are needed before it could be recommended for supplementation, treatment or prevention of some of the diseases discussed in this review.
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Affiliation(s)
- Siaw-Cheok Liew
- Clinical Skills and Simulation Centre, International Medical University, Kuala Lumpur, Malaysia
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Lin VC, Lu TL, Yin HL, Yang SF, Lee YC, Liu CC, Huang CY, Yu CC, Chang TY, Huang SP, Bao BY. Prognostic Relevance of Methylenetetrahydrofolate Reductase Polymorphisms for Prostate Cancer. Int J Mol Sci 2016; 17:E1996. [PMID: 27916838 PMCID: PMC5187796 DOI: 10.3390/ijms17121996] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 11/18/2016] [Accepted: 11/24/2016] [Indexed: 01/03/2023] Open
Abstract
Folate metabolism has been associated with cancers via alterations in nucleotide synthesis, DNA methylation, and DNA repair. We hypothesized that genetic variants in methylenetetrahydrofolate reductase (MTHFR), a key enzyme of folate metabolism, would affect the prognosis of prostate cancer. Three haplotype-tagging single-nucleotide polymorphisms (SNPs) across the MTHFR gene region were genotyped in a cohort of 458 patients with clinically localized prostate cancer treated with radical prostatectomy. One SNP, rs9651118, was associated with disease recurrence, and the association persisted after multivariate analyses adjusting for known risk factors. Public dataset analyses suggested that rs9651118 affects MTHFR expression. Quantitative real-time polymerase chain reaction analysis revealed that MTHFR expression is significantly upregulated in prostate tumor tissues when compared with adjacent normal tissues. Furthermore, overexpression of MTHFR correlates with cancer recurrence and death in two independent publicly available prostate cancer datasets. In conclusion, our data provide rationale to further validate the clinical utility of MTHFR rs9651118 as a biomarker for prognosis in prostate cancer.
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Affiliation(s)
- Victor C Lin
- Department of Urology, E-Da Hospital, Kaohsiung 824, Taiwan.
- School of Medicine for International Students, I-Shou University, Kaohsiung 840, Taiwan.
| | - Te-Ling Lu
- Department of Pharmacy, China Medical University, Taichung 404, Taiwan.
| | - Hsin-Ling Yin
- Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan.
- Department of Pathology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Sheau-Fang Yang
- Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan.
- Department of Pathology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Yung-Chin Lee
- Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan.
- Department of Urology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Chia-Chu Liu
- Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan.
- Department of Urology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Chao-Yuan Huang
- Department of Urology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei 100, Taiwan.
- Department of Urology, National Taiwan University Hospital Hsin-Chu Branch, Hsinchu 300, Taiwan.
| | - Chia-Cheng Yu
- Division of Urology, Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan.
- Department of Urology, School of Medicine, National Yang-Ming University, Taipei 112, Taiwan.
- Department of Pharmacy, Tajen University, Pingtung 907, Taiwan.
| | - Ta-Yuan Chang
- Department of Occupational Safety and Health, China Medical University, Taichung 404, Taiwan.
| | - Shu-Pin Huang
- Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan.
- Department of Urology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Bo-Ying Bao
- Department of Pharmacy, China Medical University, Taichung 404, Taiwan.
- Sex Hormone Research Center, China Medical University Hospital, Taichung 404, Taiwan.
- Department of Nursing, Asia University, Taichung 413, Taiwan.
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Barrio-Real L, Benedetti LG, Engel N, Tu Y, Cho S, Sukumar S, Kazanietz MG. Subtype-specific overexpression of the Rac-GEF P-REX1 in breast cancer is associated with promoter hypomethylation. Breast Cancer Res 2014; 16:441. [PMID: 25248717 PMCID: PMC4303123 DOI: 10.1186/s13058-014-0441-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 09/01/2014] [Indexed: 01/30/2023] Open
Abstract
Introduction The Rac-GEF P-REX1 is a key mediator of ErbB signaling in breast cancer recently implicated in mammary tumorigenesis and metastatic dissemination. Although P-REX1 is essentially undetectable in normal human mammary epithelial tissue, this Rac-GEF is markedly upregulated in human breast carcinomas, particularly of the luminal subtype. The mechanisms underlying P-REX1 upregulation in breast cancer are unknown. Toward the goal of dissecting the mechanistic basis of P-REX1 overexpression in breast cancer, in this study we focused on the analysis of methylation of the PREX1 gene promoter. Methods To determine the methylation status of the PREX1 promoter region, we used bisulfite genomic sequencing and pyrosequencing approaches. Re-expression studies in cell lines were carried out by treatment of breast cancer cells with the demethylating agent 5-aza-2′-deoxycitidine. PREX1 gene methylation in different human breast cancer subtypes was analyzed from the TCGA database. Results We found that the human PREX1 gene promoter has a CpG island located between -1.2 kb and +1.4 kb, and that DNA methylation in this region inversely correlates with P-REX1 expression in human breast cancer cell lines. A comprehensive analysis of human breast cancer cell lines and tumors revealed significant hypomethylation of the PREX1 promoter in ER-positive, luminal subtype, whereas hypermethylation occurs in basal-like breast cancer. Treatment of normal MCF-10A or basal-like cancer cells, MDA-MB-231 with the demethylating agent 5-aza-2′-deoxycitidine in combination with the histone deacetylase inhibitor trichostatin A restores P-REX1 levels to those observed in luminal breast cancer cell lines, suggesting that aberrant expression of P-REX1 in luminal breast cancer is a consequence of PREX1 promoter demethylation. Unlike PREX1, the pro-metastatic Rho/Rac-GEF, VAV3, is not regulated by methylation. Notably, PREX1 gene promoter hypomethylation is a prognostic marker of poor patient survival. Conclusions Our study identified for the first time gene promoter hypomethylation as a distinctive subtype-specific mechanism for controlling the expression of a key regulator of Rac-mediated motility and metastasis in breast cancer. Electronic supplementary material The online version of this article (doi:10.1186/s13058-014-0441-7) contains supplementary material, which is available to authorized users.
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Deregulation of MYC and TP53 through genetic and epigenetic alterations in gallbladder carcinomas. Clin Exp Med 2014; 15:421-6. [PMID: 25200035 DOI: 10.1007/s10238-014-0311-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 08/26/2014] [Indexed: 12/11/2022]
Abstract
Gallbladder cancer is a rare malignancy and presents a poor prognosis. MYC and p53 have been implicated in gallbladder carcinogenesis. However, little is known about the molecular mechanisms involved in their regulation in this neoplasia. Here, we evaluated the MYC and TP53 copy numbers in gallbladder tumors and their possible association with protein expression. We also investigated whether MYC may be controlled by mutations and DNA promoter methylation. In the present study, 15 samples of invasive gallbladder carcinomas and six control samples were analyzed. On the other hand, the expression of MYC and p53 was more frequent in gallbladder carcinomas than in control samples (p = 0.002, p = 0.046, respectively). Gain of copies of the MYC and TP53 genes was detected in 86.7 and 50 % of gallbladder carcinomas, respectively. MYC and TP53 amplifications were associated with immunoreactivity of their protein (p = 0.029, p = 0.001, respectively). MYC hypomethylation was only detected in tumoral samples and was associated with its protein expression (p = 0.029). MYC mutations were detected in 80 % of tumor samples. The G allele at rs117856857 was associated with the presence of gallbladder tumors (p = 0.019) and with MYC expression (p = 0.044). Moreover, two tumors presented a pathogenic mutation in MYC exon 2 (rs28933407). Our study highlights that the gain of MYC and TP53 copies seems to be a frequent finding in gallbladder cancer. In addition, gain of copies, hypomethylation and point mutations at MYC may contribute to overexpression of its protein in this type of cancer.
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de Souza CRT, Leal MF, Calcagno DQ, Costa Sozinho EK, Borges BDN, Montenegro RC, Dos Santos AKCR, Dos Santos SEB, Ribeiro HF, Assumpção PP, de Arruda Cardoso Smith M, Burbano RR. MYC deregulation in gastric cancer and its clinicopathological implications. PLoS One 2013; 8:e64420. [PMID: 23717612 PMCID: PMC3661519 DOI: 10.1371/journal.pone.0064420] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 04/12/2013] [Indexed: 12/13/2022] Open
Abstract
Our study investigated the relationship between MYC alterations and clinicopathological features in gastric cancers. We evaluated the effect of MYC mRNA expression and its protein immunoreactivity, as well as copy number variation, promoter DNA methylation, and point mutations, in 125 gastric adenocarcinoma and 67 paried non-neoplastic tissues. We observed that 77% of the tumors presented MYC immunoreactivity which was significantly associated with increased mRNA expression (p<0.05). These observations were associated with deeper tumor extension and the presence of metastasis (p<0.05). MYC protein expression was also more frequently observed in intestinal-type than in diffuse-type tumors (p<0.001). Additionally, MYC mRNA and protein expression were significantly associated with its copy number (p<0.05). The gain of MYC copies was associated with late-onset, intestinal-type, advanced tumor stage, and the presence of distant metastasis (p<0.05). A hypomethylated MYC promoter was detected in 86.4% of tumor samples. MYC hypomethylation was associated with diffuse-type, advanced tumor stage, deeper tumor extension, and the presence of lymph node metastasis (p<0.05). Moreover, eighteen tumor samples presented at least one known mutation. The presence of MYC mutations was associated with diffuse-type tumor (p<0.001). Our results showed that MYC deregulation was mainly associated with poor prognostic features and also reinforced the presence of different pathways involved in intestinal-type and diffuse-type gastric carcinogenesis. Thus, our findings suggest that MYC may be a useful marker for clinical stratification and prognosis.
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Calcagno DQ, Gigek CO, Chen ES, Burbano RR, Smith MDAC. DNA and histone methylation in gastric carcinogenesis. World J Gastroenterol 2013; 19:1182-92. [PMID: 23482412 PMCID: PMC3587474 DOI: 10.3748/wjg.v19.i8.1182] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 06/13/2012] [Accepted: 06/28/2012] [Indexed: 02/06/2023] Open
Abstract
Epigenetic alterations contribute significantly to the development and progression of gastric cancer, one of the leading causes of cancer death worldwide. Epigenetics refers to the number of modifications of the chromatin structure that affect gene expression without altering the primary sequence of DNA, and these changes lead to transcriptional activation or silencing of the gene. Over the years, the study of epigenetic processes has increased, and novel therapeutic approaches that target DNA methylation and histone modifications have emerged. A greater understanding of epigenetics and the therapeutic potential of manipulating these processes is necessary for gastric cancer treatment. Here, we review recent research on the effects of aberrant DNA and histone methylation on the onset and progression of gastric tumors and the development of compounds that target enzymes that regulate the epigenome.
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Alevizos L, Gomatos IP, Smparounis S, Konstadoulakis MM, Zografos G. Review of the molecular profile and modern prognostic markers for gastric lymphoma: how do they affect clinical practice? Can J Surg 2012; 55:117-24. [PMID: 22564515 DOI: 10.1503/cjs.002310] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Primary gastric lymphoma is a rare cancer of the stomach with an indeterminate prognosis. Recently, a series of molecular prognostic markers has been introduced to better describe this clinical entity. This review describes the clinical importance of several oncogenes, apoptotic genes and chromosomal mutations in the initiation and progress of primary non-Hodgkin gastric lymphoma and their effect on patient survival. We also outline the prognostic clinical importance of certain cellular adhesion molecules, such as ICAM and PECAM-1, in patients with gastric lymphoma, and we analyze the correlation of these molecules with apoptosis, angiogenesis, tumour growth and metastatic potential. We also focus on the host-immune response and the impact of Helicobacter pylori infection on gastric lymphoma development and progression. Finally, we explore the therapeutic methods currently available for gastric lymphoma, comparing the traditional invasive approach with more recent conservative options, and we stress the importance of the application of novel molecular markers in clinical practice.
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Affiliation(s)
- Leonidas Alevizos
- 1st Department of Propaedeutic Surgery, Hippokration Hospital of Athens, Athens Medical School, Vasilissis, Sofia Avenue 114, 11527, Athens, Greece
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Hou L, Zhang X, Wang D, Baccarelli A. Environmental chemical exposures and human epigenetics. Int J Epidemiol 2012; 41:79-105. [PMID: 22253299 PMCID: PMC3304523 DOI: 10.1093/ije/dyr154] [Citation(s) in RCA: 279] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2011] [Indexed: 02/06/2023] Open
Abstract
Every year more than 13 million deaths worldwide are due to environmental pollutants, and approximately 24% of diseases are caused by environmental exposures that might be averted through preventive measures. Rapidly growing evidence has linked environmental pollutants with epigenetic variations, including changes in DNA methylation, histone modifications and microRNAs. Environ mental chemicals and epigenetic changes All of these mechanisms are likely to play important roles in disease aetiology, and their modifications due to environmental pollutants might provide further understanding of disease aetiology, as well as biomarkers reflecting exposures to environmental pollutants and/or predicting the risk of future disease. We summarize the findings on epigenetic alterations related to environmental chemical exposures, and propose mechanisms of action by means of which the exposures may cause such epigenetic changes. We discuss opportunities, challenges and future directions for future epidemiology research in environmental epigenomics. Future investigations are needed to solve methodological and practical challenges, including uncertainties about stability over time of epigenomic changes induced by the environment, tissue specificity of epigenetic alterations, validation of laboratory methods, and adaptation of bioinformatic and biostatistical methods to high-throughput epigenomics. In addition, there are numerous reports of epigenetic modifications arising following exposure to environmental toxicants, but most have not been directly linked to disease endpoints. To complete our discussion, we also briefly summarize the diseases that have been linked to environmental chemicals-related epigenetic changes.
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Affiliation(s)
- Lifang Hou
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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Kwon OH, Park JL, Kim M, Kim JH, Lee HC, Kim HJ, Noh SM, Song KS, Yoo HS, Paik SG, Kim SY, Kim YS. Aberrant up-regulation of LAMB3 and LAMC2 by promoter demethylation in gastric cancer. Biochem Biophys Res Commun 2011; 406:539-45. [PMID: 21345334 DOI: 10.1016/j.bbrc.2011.02.082] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 02/16/2011] [Indexed: 01/03/2023]
Abstract
The LAMB3 and LAMC2 genes encode the laminin-5 β3 and γ2 chains, respectively, which are parts of laminin-5, one of the major components of the basement membrane zone. Here, we report the frequent up-regulation of LAMB3 and LAMC2 by promoter demethylation in gastric cancer. Gene expression data analysis showed that LAMB3 and LAMC2 were up-regulated in various tumor tissues. Combined analyses of DNA methylation and gene expression of both genes in gastric cancer cell lines and tissues showed that DNA hypomethylation was associated with the up-regulation of both genes. Treatment with a methylation inhibitor induced LAMB3 and LAMC2 expression in gastric cancer cell lines in which both genes were silenced. By chromatin immunoprecipitation assay, we showed the activation histone mark H3K4me3 was associated with the expression of both genes. The expression level of LAMB3 affected multiple malignant phenotypes in gastric cancer cell lines. These results suggest that epigenetic activation of LAMB3 and LAMC2 may play an important role in gastric carcinogenesis.
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Affiliation(s)
- Oh-Hyung Kwon
- Medical Genomics Research Center, University of Science and Technology, KRIBB, and Daejeon 305-806, Republic of Korea
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Abstract
DNA methylation plays an important role in regulating normal development and carcinogenesis. Current understanding of the biological roles of DNA methylation is limited to its role in the regulation of gene transcription, genomic imprinting, genomic stability, and X chromosome inactivation. In the past 2 decades, a large number of changes have been identified in cancer epigenomes when compared with normals. These alterations fall into two main categories, namely, hypermethylation of tumor suppressor genes and hypomethylation of oncogenes or heterochromatin, respectively. Aberrant methylation of genes controlling the cell cycle, proliferation, apoptosis, metastasis, drug resistance, and intracellular signaling has been identified in multiple cancer types. Recent advancements in whole-genome analysis of methylome have yielded numerous differentially methylated regions, the functions of which are largely unknown. With the development of high resolution tiling microarrays and high throughput DNA sequencing, more cancer methylomes will be profiled, facilitating the identification of new candidate genes or ncRNAs that are related to oncogenesis, new prognostic markers, and the discovery of new target genes for cancer therapy.
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Affiliation(s)
- Hoi-Hung Cheung
- Section on Developmental Genomics, Laboratory of Clinical Genomics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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13
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Calcagno DQ, Leal MF, Assumpção PP, Smith MDAC, Burbano RR. MYC and gastric adenocarcinoma carcinogenesis. World J Gastroenterol 2008; 14:5962-8. [PMID: 18932273 PMCID: PMC2760197 DOI: 10.3748/wjg.14.5962] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
MYC is an oncogene involved in cell cycle regulation, cell growth arrest, cell adhesion, metabolism, ribosome biogenesis, protein synthesis, and mitochondrial function. It has been described as a key element of several carcinogenesis processes in humans. Many studies have shown an association between MYC deregulation and gastric cancer. MYC deregulation is also seen in gastric preneoplastic lesions and thus it may have a role in early gastric carcinogenesis. Several studies have suggested that amplification is the main mechanism of MYC deregulation in gastric cancer. In the present review, we focus on the deregulation of the MYC oncogene in gastric adenocarcinoma carcinogenesis, including its association with Helicobacter pylori (H pylori) and clinical applications.
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Ren H, Du N, Zhang J, Yao J, Shi JS. Variabilities of serum proteomic spectra in patients with gastric cancer before and after operation. Shijie Huaren Xiaohua Zazhi 2008; 16:314-318. [DOI: 10.11569/wcjd.v16.i3.314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To study the variabilities of serum proteomic spectra in patients with gastric cancer before and after operation in order to detect specific protein markers that can be used in the rapid diagnosis of gastric cancer.
METHODS: Proteomic spectra of 46 serum samples from patients with gastric cancer before and after operation and 40 from normal individuals were generated by IMAC-Cu protein chip and surface-enhanced laser desorption/ionization time of flight mass spectrometry (SELDI-TOF-MS).
RESULTS: Fourteen differentially expressed proteins in serum were screened by analysis of proteomic spectra in preoperative patients and normal individuals. We obtained 4 proteins (heat shock protein 27, glucose-regulated protein, prohibitin, protein disulfide isomerase A3) as markers able to classify gastric cancer patients and normal individuals. The sensitivity and specificity of these markers were 95.7% and 92.5%, respectively. The proteins over-expressed in serum of preoperative patients were obviously down-regulated.
CONCLUSION: Specific proteinic markers of gastric cancer can be detected in serum and used both in the rapid diagnosis of gastric cancer and in the judgment of prognosis. SELDI-TOF-MS is a useful tool for the detection and identification of new protein markers in serum.
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Csepregi A, Röcken C, Hoffmann J, Gu P, Saliger S, Müller O, Schneider-Stock R, Kutzner N, Roessner A, Malfertheiner P, Ebert MPA. APC promoter methylation and protein expression in hepatocellular carcinoma. J Cancer Res Clin Oncol 2007; 15:1415-28. [PMID: 20629990 PMCID: PMC4373337 DOI: 10.1111/j.1582-4934.2010.01124.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE We investigated the impact of promoter methylation on APC protein expression in patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS 50 patients [HCC (n=19), liver metastasis (n=19), cholangiocellular cancer (n=7), and benign liver tumors (n=5)] were studied for methylation using Methylight analysis. APC mutation was investigated by protein truncation test and direct sequencing of genomic DNA. The protein expression was evaluated by immunohistochemistry and Western blot analysis. RESULTS The APC promoter was hypermethylated in 81.8% of non-cancerous liver tissue samples. All HCC samples and ten patients with liver metastasis (52.6%) exhibited APC promoter methylation. The degree of methylation was significantly higher in samples from HCC compared to the non-cancerous liver tissue samples (63.1% vs. 24.98%; p=0.001). The level of APC protein expression was significantly reduced in HCC samples compared to that of the corresponding non-tumor liver tissue (p<0.05). CONCLUSIONS Promoter methylation of the APC gene seems to be of significance in hepatocarcinogenesis and results in reduced protein expression in HCC. Interestingly, APC promoter methylation is also present in the vast majority of non-cancerous liver tissue whose (patho)physiological function remains unresolved.
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Affiliation(s)
- Antal Csepregi
- Department of Gastroenterology, Hepatology, and Infectious Diseases, Otto-von-Guericke University, Leipziger Strasse 44, 39120 Magdeburg, Germany.
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16
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Weng YR, Sun DF, Fang JY, Gu WQ, Zhu HY. Folate levels in mucosal tissue but not methylenetetrahydrofolate reductase polymorphisms are associated with gastric carcinogenesis. World J Gastroenterol 2006; 12:7591-7. [PMID: 17171786 PMCID: PMC4088039 DOI: 10.3748/wjg.v12.i47.7591] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To evaluate whether folate levels in mucosal tissue and some common methylenetetrahydrofolate reductase (MTHFR) variants are associated with the risk of gastric cancer through DNA methylation.
METHODS: Real-time PCR was used to study the expression of tumor related genes in 76 mucosal tissue samples from 38 patients with gastric cancer. Samples from the gastroscopic biopsy tissues of 34 patients with chronic superficial gastritis (CSG) were used as controls. Folate concentrations in these tissues were detected by the FOL ACS: 180 automated chemiluminescence system. MTHFR polymorphisms were analyzed by PCR-RFLP, and the promoter methylation of tumor-related genes was determined by methylation-specific PCR (MSP).
RESULTS: Folate concentrations were significantly higher in CSG than in cancerous tissues. Decreased expression and methylation of c-myc accompanied higher folate concentrations. Promoter hypermethylation and loss of p16INK4A in samples with MTHFR 677CC were more frequent than in samples with the 677TT or 677CT genotype. And the promoter hypermethylation and loss of p21WAF1 in samples with MTHFR 677CT were more frequent than when 677CC or 677TT was present. The 677CT genotype showed a non-significant higher risk for gastric cancer as compared with the 677CC genotype.
CONCLUSION: Lower folate levels in gastric mucosal tissue may confer a higher risk of gastric carcinogenesis through hypomethylation and overexpression of c-myc.
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Affiliation(s)
- Yu-Rong Weng
- Shanghai Institute of Digestive Disease, Shanghai Jiao-Tong University School of Medicine, Renji Hospital, Shanghai 200001, China
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17
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Kim KH, Choi JS, Kim IJ, Ku JL, Park JG. Promoter hypomethylation and reactivation of MAGE-A1 and MAGE-A3 genes in colorectal cancer cell lines and cancer tissues. World J Gastroenterol 2006; 12:5651-7. [PMID: 17007017 PMCID: PMC4088165 DOI: 10.3748/wjg.v12.i35.5651] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To verify the expression and methylation status of the MAGE-A1 and MAGE-A3 genes in colorectal cancer tissues and cancer cell lines.
METHODS: We evaluated promoter demethylation status of the MAGE-A1 and MAGE-A3 genes by RT-PCR analysis and methylation-specific PCR (MS-PCR), as well as sequencing analysis, after sodium bisulfite modification in 32 colorectal cancer cell lines and 87 cancer tissues.
RESULTS: Of the 32 cell lines, MAGE-A1 and MAGE-A3 expressions were observed in 59% and 66%, respectively. Subsequent to sodium bisulfite modification and MS-PCR analysis, the promoter hypomethylation of MAGE-A1 and MAGE-A3 was confirmed in both at 81% each. Promoter hypomethylation of MAGE-A1 and MAGE-A3 in colorectal cancer tissues was observed in 43% and 77%, respectively. Hypomethylation of MAGE-A1 and MAGE-A3 genes in corresponding normal tissues were observed in 2% and 6%, respectively.
CONCLUSION: The promoter hypomethylation of MAGE genes up-regulates its expression in colorectal carcinomas as well as in gastric cancers and might play a significant role in the development and progression of human colorectal carcinomas.
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MESH Headings
- Antigens, Neoplasm/genetics
- Antigens, Neoplasm/metabolism
- Antimetabolites, Antineoplastic/pharmacology
- Azacitidine/analogs & derivatives
- Azacitidine/pharmacology
- Cell Line, Tumor
- Colorectal Neoplasms/genetics
- Colorectal Neoplasms/metabolism
- Colorectal Neoplasms/pathology
- DNA Methylation
- DNA, Neoplasm/genetics
- DNA, Neoplasm/metabolism
- Decitabine
- Gene Expression Regulation, Neoplastic/genetics
- Humans
- Melanoma-Specific Antigens
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Promoter Regions, Genetic/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Stomach Neoplasms/genetics
- Stomach Neoplasms/metabolism
- Stomach Neoplasms/pathology
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Affiliation(s)
- Kyung-Hee Kim
- Laboratory of Cell Biology, Cancer Research Institute, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-744, Korea
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18
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Plass C, Smiraglia DJ. Genome-wide Analysis of DNA Methylation Changes in Human Malignancies. Curr Top Microbiol Immunol 2006; 310:179-98. [PMID: 16909911 DOI: 10.1007/3-540-31181-5_9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
DNA methylation is an epigenetic modification of the DNA sequence and thus does not change the genetic code but affects chromosomal stability and gene expression. DNA methylation patterns are heritable and can be passed on to the daughter cell. In this review, we briefly summarize our current knowledge on normal DNA methylation patterns and move on to discuss the current state of the field with respect to altered DNA methylation in cancer. We make a special attempt to address current questions relating to genome-wide DNA methylation patterns. Since DNA methylation is used as a therapeutic target in clinical studies, it is of utmost importance to define potential target sequences that could be used as diagnostic or prognostic markers. We conclude the review by outlining possible scenarios that may explain tumor type-specific DNA methylation patterns described by assays evaluating genome-wide levels of DNA methylation.
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Affiliation(s)
- C Plass
- Division of Human Cancer Genetics, The Ohio State University, Tzagournis Medical Research Facility, Columbus 43210, USA.
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19
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Weng YR, Fang JY, Sun DF, Chen ZF, Lu R, Gu WQ, Zhu HY. Methylation and expression of tumor-related genes and their associations with folate and MTHFR gene polymorphisms in gastric cancerous tissues. Shijie Huaren Xiaohua Zazhi 2006; 14:2192-2198. [DOI: 10.11569/wcjd.v14.i22.2192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the methylation and expression of c-myc oncogenes, p16INK4A, p21WAF1, hMLH1 and hMSH2 tumor suppressor genes, and their associations with folate and methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms in gastric cancerous tissues.
METHODS: Paired samples of primary gastric cancer and corresponding para-cancerous, non-cancerous gastric mucosa were obtained from surgically resected specimens of 38 patients, and the latter were used as controls. Folate concentration was detected by FOL ACS: 180 automated chemiluminescence system. Two common polymorphisms of MTHFR gene were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The mRNA expression of tumor-related gene was detected by real-time reverse transcription-PCR (RT-PCR). The methylation status of gene promoter was determined by methylation-specific PCR (MSP).
RESULTS: Up-regulation of c-myc, down-regulation of p16INK4A, hMLH1 and hMSH2 expression were associated with the aberrant methylation of gene promoters in gastric canceous mucosae, while p21WAF1 expression was not. Down-regulation of p21WAF1 and hMSH2 expression, hypermethylation of p16INK4A were associated with low folate level. Over-expression and hypomethylation of c-myc coexisted with low folate level. 677CC genotype of MTHFR showed hypermethylation and down-regulation of p16INK4A expression, and there was no significant relationship between the two common polymorphisms of MTHFR and the methylation and expression of the other tumor-related genes.
CONCLUSION: DNA methylation plays an important role in human gastric carcinogenesis. Folate level and MTHFR gene polymorphisms may regulate the expression of tumor-related genes by affecting the methylation status.
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20
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Ren H, Du N, Liu G, Hu HT, Tian W, Deng ZP, Shi JS. Analysis of variabilities of serum proteomic spectra in patients with gastric cancer before and after operation. World J Gastroenterol 2006; 12:2789-92. [PMID: 16718772 PMCID: PMC4130994 DOI: 10.3748/wjg.v12.i17.2789] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To study the variabilities of serum proteomic spectra in patients with gastric cancer before and after operation in order to detect the specific protein markers that can be used for quick diagnosis of gastric cancer.
METHODS: Proteomic spectra of 46 serum samples from patients with gastric cancer before and after operation and 40 from normal individuals were generated by IMAC-Cu protein chip and surface-enhanced laser desorption/ ionization time of flight mass spectrometry.
RESULTS: Fourteen differentially expressed proteins in serum were screened by analysis of proteomic spectra of preoperative patients and normal individuals. We obtained 4 proteins (heat shock protein 27, glucose-regulated protein, prohibitin, protein disulfide isomerase A3) making up marker pattern which was able to class the patient-team and normal-team. These marker patterns yielded 95.7% sensitivity and 92.5% specificity, respectively. The proteins over-expressed in serum of preoperative patients were obviously down-regulated.
CONCLUSION: Specific protein markers of gastric cancer can be used for the quick diagnosis of gastric cancer and judgment of prognosis. SELDI-TOF-MS is a useful tool for the detection and identification of new protein markers in serum.
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Affiliation(s)
- Hong Ren
- Department of Oncosurgery, First Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi Province, China.
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21
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Graziano F, Kawakami K, Ruzzo A, Watanabe G, Santini D, Pizzagalli F, Bisonni R, Mari D, Floriani I, Catalano V, Silva R, Tonini G, Torri V, Giustini L, Magnani M. Methylenetetrahydrofolate reductase 677C/T gene polymorphism, gastric cancer susceptibility and genomic DNA hypomethylation in an at-risk Italian population. Int J Cancer 2006; 118:628-32. [PMID: 16094648 DOI: 10.1002/ijc.21397] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We performed a case-control study to examine the relationship between MTHFR C677T gene polymorphism (MTHFR677C/T) and gastric cancer susceptibility in at-risk populations in central Italy. To explore genomic DNA hypomethylation as a potential etiologic mechanism, this phenomenon was evaluated in carriers of the MTHFR677T/T genotype and carriers of the wild-type MTHFR677C/C genotype. Lymphocyte genomic DNA from 162 gastric cancer patients and 164 controls was used for MTHFR677C/T genotyping. Unconditional regression analysis with ORs and 95% CIs was used to investigate the association of the polymorphism with disease. Genomic DNA methylation status by an established enzymatic assay that measures the DNA accepting capacity of methyl groups (inversely related to endogenous methylation) was assessed in a random sample of 40 carriers of the wild-type MTHFR677C/C genotype and 40 carriers of the MTHFR677T/T genotype. The global allelic distribution was in Hardy-Weinberg equilibrium. The MTHFR677T allele was significantly associated with gastric cancer risk with an OR of 2.49 (95% CI 1.48-4.20) in heterozygous MTHFR677C/T carriers and an OR of 2.85 (95% CI 1.52-5.35) in homozygous MTHFR677T/T carriers. This risk association was retained in subgroup analyses by tumor histotype and location. Genomic DNA hypomethylation status in MTHFR677T/T carriers was significantly higher than in subjects with wild-type MTHF677C/C genotype (p = 0.012). In the studied population, MTHFR677T played the role of a moderate-penetrance gastric cancer susceptibility allele. Possession of the MTHFR677T/T genotype was significantly associated with genomic DNA hypomethylation. These findings deserve further investigation in the context of novel strategies for gastric cancer prevention.
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22
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Geter DR, Moore TM, George MH, Kilburn SR, Allen JW, Nelson GM, Winkfield E, DeAngelo AB. Tribromomethane exposure and dietary folate deficiency in the formation of aberrant crypt foci in the colons of F344/N rats. Food Chem Toxicol 2005; 43:1405-12. [PMID: 15921841 DOI: 10.1016/j.fct.2005.03.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 03/21/2005] [Accepted: 03/30/2005] [Indexed: 12/25/2022]
Abstract
Folate and folic acid are forms of the B vitamin that are involved in the synthesis, repair, and functioning of DNA and are required for the production and maintenance of cells. Low levels of folate have been associated with several forms of cancer, including colon cancer. Aberrant crypt foci (ACF), identified as putative precursor lesions in the development of colon cancer, have been induced by the drinking water disinfection by-product, tribromomethane (TBM). To investigate whether ACF induced by TBM could be promoted by a diet devoid of dietary folate, male F344/N rats were exposed to 500 mg/l of TBM in drinking water and fed either a normal or no folate diet (NFD) for 26 weeks. At the conclusion of the study, colons were excised and examined for ACF. Rats exposed to TBM and fed a NFD, evident by significantly reduced serum folate concentrations and elevated serum homocysteine levels, had significant increases of ACF when compared to rats exposed to TBM and fed a normal diet. This study highlights the important role that diet, especially folate intake, represents in protecting the colon against TBM-induced ACF.
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Affiliation(s)
- David R Geter
- National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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23
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Yang L, Zhu HY, Cheng ZH, Lu R, Chen YX, Fang JY. Expression and methylation of tumor-associated genes in human gastric cancer cell lines. Shijie Huaren Xiaohua Zazhi 2005; 13:1493-1498. [DOI: 10.11569/wcjd.v13.i13.1493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the expression and methylation of tumor suppressor genes and oncogenes in the carcinogenesis of gastric cancer, and to further explore new methods for the treatment of gastric cancer.
METHODS: The gastric cancer MKN-45 and HGC-27 cell lines were cultured and then exposed to different concentrations (2 μmol/L, 5 μmol/L and 10 μmol/L) of 5-aza-2'-deoxycytidine (5-aza-dC) for 24 and 72 h. MTT assay was used to examine the viability of the cells. Then the DNA and RNA of the cells were extracted and the expression of p16INK4A, p21WAF1, p53, c-myc, and c-Ha-ras were detected by reverse transcription polymerase chain reaction (RT-PCR). At the same time, the cell cycles of MKN-45 and HGC-27 were observed by flow cytometry. Bisulfite modification and sequencing and methylation-specific PCR were used to detect the methylation of p16INK4A and c-myc promoter region.
RESULTS: The concentrations and exposed time of 5-aza-dC had no significant effect on the viability of gastric cancer cells. p16INK4A was expressed in both MKN-45 and HGC-27 cells before treatment. After treated with 5-aza-dC, p16INK4A expression was increased in both kinds of the cells, and the 5-aza-dC concentration and exposed time were different between the two kinds of cells when the most markedly increased expression of p16INK4A appeared. p53, p21WAF1, c-myc and c-Ha-ras were all expressed before and after treatment. HGC-27 cells were blocked at G1 period, but no changes of MKN-45 cell cycle were observed. Methylation in p16INK4A promoter region occurred so that the expression of this gene was reduced. After treated with demethylation agent 5-aza-dC, the expression of p16INK4A was increased.
CONCLUSION: Methylation regulates the expression of p16INK4A, but not p21WAF1, p53, c-myc, and c-Ha-ras. 5-aza-dC can up-regulate the transcription of tumor suppressor gene through demethylation, in which its concentration and exposed time play an important role.
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24
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Fang JY, Cheng ZH, Chen YX, Lu R, Yang L, Zhu HY, Lu LG. Expression of Dnmt1, demethylase, MeCP2 and methylation of tumor-related genes in human gastric cancer. World J Gastroenterol 2004; 10:3394-8. [PMID: 15526354 PMCID: PMC4576216 DOI: 10.3748/wjg.v10.i23.3394] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIM: To explore the effect of DNA methyltransferase, demethylase and methyl-CpG binding protein MeCP2 on the expressions and methylation of hMSH2 and proto-oncogene in human gastric cancer.
METHODS: Paired samples of primary gastric cancer and corresponding para-cancerous, non-cancerous gastric mucosae were obtained from surgically resected specimens of 28 patients. Transcription levels of Dnmt1, mbd2, MeCP2, p16INK4A, hMSH2 and c-myc were detected by using real-time PCR or RT-PCR. Promoter methylation of p16INK4A, c-myc and hMSH2 genes was assayed by methylation-specific PCR (MSP) and sequencing (mapping). Their relationships were analyzed by Fisher’s exact test using the software SPSS.
RESULTS: The average mRNA level of Dnmt1 gene from cancerous tissue was higher and that of mbd2 gene from cancerous tissue was lower than that from non-cancerous tissue, respectively. mbd2 was lower in cancerous tissue than in non-cancerous tissue in 14 (50.0%) of patients but higher in 3 cases (10.7%) of non-cancerous gastric tissue (P < 0.001). c-myc expression was up-regulated in cancer tissues (P < 0.05). The up-regulation of mbd2 was found in all patients with hypomethylated c-myc. The transcriptional levels of p16INK4A and MeCP2 genes did not display any difference between gastric cancerous and matched non-cancerous tissues. There were down-regulation and hypermethylation of hMSH2 in cancer tissues, and the hypermethylation of hMSH2 coexisted with down-regulated transcription. However, the transcription level of the above genes was not associated with biological behaviours of gastric cancers.
CONCLUSION: The up-regulation of proto-oncogene may be the consequence of epigenetic control of gene expression by demethylase, and mbd2 is involved in the regulation of hMSH2 expression in human gastric cancer.
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Affiliation(s)
- Jing-Yuan Fang
- Shanghai Institute of Digestive Disease, Shanghai Second Medical University Renji Hospital, Shanghai 200001, China.
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25
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Narayanan S, McConnell J, Little J, Sharp L, Piyathilake CJ, Powers H, Basten G, Duthie SJ. Associations between Two Common Variants C677T and A1298C in the Methylenetetrahydrofolate Reductase Gene and Measures of Folate Metabolism and DNA Stability (Strand Breaks, Misincorporated Uracil, and DNA Methylation Status) in Human Lymphocytes In vivo. Cancer Epidemiol Biomarkers Prev 2004. [DOI: 10.1158/1055-9965.1436.13.9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Abstract
Objective: Homozygosity for variants of the methylenetetrahydrofolate reductase (MTHFR) gene is associated with decreased risk for colorectal cancer. We have investigated the relationships between two variants of the MTHFR gene (C677T and A1298C) and blood folate, homocysteine, and genomic stability (strand breakage, misincorporated uracil, and global cytosine methylation in lymphocytes) in a study of 199 subjects. Results: The frequencies of homozygosity for the C677T and A1298C variants of the MTHFR gene were 12.6% and 14.6%, respectively. Plasma homocysteine, folate, vitamin B12, 5-methyltetrahydrofolate, and RBC folate were determined in the C677T genotypes. Plasma folate was significantly lower (P < 0.001) in the homozygous variants (6.7 ± 0.6 ng/mL) compared with wild-types (8.8 ± 0.4 ng/mL) and heterozygotes (9.1 ± 0.5 ng/mL). Homocysteine was significantly higher (P < 0.05) in homozygous variants (13.2 ± 1.1 μmol/L) compared with homozygous subjects (10.9 ± 0.4 μmol/L). Homozygous variants had significantly lower (P < 0.05) RBC folate (84.7 ± 6.3 ng/mL) compared with wild-types (112.2 ± 5.2 ng/mL) and heterozygous individuals (125.1 ± 6.6 ng/mL). No significant difference in RBC folate was observed between wild-types and heterozygotes. The A1298C variant did not influence plasma homocysteine, folate, 5-methyltetrahydrofolate, vitamin B12, or RBC folate. Lymphocyte DNA stability biomarkers (strand breaks, misincorporated uracil, and global DNA methylation) were similar for all MTHFR C677T or A1298C variants. Conclusion: Data from this study do not support the hypothesis that polymorphisms in the MTHFR gene increase DNA stability by sequestering 5,10-methylenetetrahydrofolate for thymidine synthesis and reducing uracil misincorporation into DNA.
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Affiliation(s)
- Sabrina Narayanan
- 1Division of Cellular Integrity, Rowett Research Institute, Aberdeen, United Kingdom
| | - Josie McConnell
- 1Division of Cellular Integrity, Rowett Research Institute, Aberdeen, United Kingdom
| | - Julian Little
- 2Epidemiology Group, Department of Medicine and Therapeutics, University of Aberdeen, Aberdeen, United Kingdom
| | - Linda Sharp
- 2Epidemiology Group, Department of Medicine and Therapeutics, University of Aberdeen, Aberdeen, United Kingdom
| | - Chandrika J. Piyathilake
- 3Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Hilary Powers
- 4Centre for Human Nutrition, University of Sheffield, Sheffield, United Kingdom
| | - Graham Basten
- 4Centre for Human Nutrition, University of Sheffield, Sheffield, United Kingdom
| | - Susan J. Duthie
- 1Division of Cellular Integrity, Rowett Research Institute, Aberdeen, United Kingdom
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26
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Christman JK. 5-Azacytidine and 5-aza-2'-deoxycytidine as inhibitors of DNA methylation: mechanistic studies and their implications for cancer therapy. Oncogene 2002; 21:5483-95. [PMID: 12154409 DOI: 10.1038/sj.onc.1205699] [Citation(s) in RCA: 1019] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
5-Azacytidine was first synthesized almost 40 years ago. It was demonstrated to have a wide range of anti-metabolic activities when tested against cultured cancer cells and to be an effective chemotherapeutic agent for acute myelogenous leukemia. However, because of 5-azacytidine's general toxicity, other nucleoside analogs were favored as therapeutics. The finding that 5-azacytidine was incorporated into DNA and that, when present in DNA, it inhibited DNA methylation, led to widespread use of 5-azacytidine and 5-aza-2'-deoxycytidine (Decitabine) to demonstrate the correlation between loss of methylation in specific gene regions and activation of the associated genes. There is now a revived interest in the use of Decitabine as a therapeutic agent for cancers in which epigenetic silencing of critical regulatory genes has occurred. Here, the current status of our understanding of the mechanism(s) by which 5-azacytosine residues in DNA inhibit DNA methylation is reviewed with an emphasis on the interactions of these residues with bacterial and mammalian DNA (cytosine-C5) methyltransferases. The implications of these mechanistic studies for development of less toxic inhibitors of DNA methylation are discussed.
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Affiliation(s)
- Judith K Christman
- Department of Biochemistry and Molecular Biology and UNMC/Eppley Cancer Center, University of Nebraska Medical Center, 984525 University Medical Center, Omaha, Nebraska, NE 68198-4525, USA.
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27
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Abstract
DNA methylation alterations are now widely recognized as a contributing factor in human tumorigenesis. A significant number of tumor suppressor genes are transcriptionally silenced by promoter hypermethylation, and recent research implicates alterations in chromatin structure as the mechanistic basis for this repression. The enzymes responsible for catalyzing DNA-cytosine methylation, as well as the proteins involved in interpreting the DNA methylation signal, have now been elucidated. Technological advances, including gene expression microarrays and genome scanning techniques, have allowed the comprehensive measurement of DNA methylation changes in human cancers. An important distinction between DNA methylation (epigenetic) and mutation or deletion (genetic) tumor suppressor gene inactivation is that epigenetic inactivation can be abrogated by small molecules, including DNA methyltransferase and histone deacetylase inhibitors. Further, strategies have been developed that combine treatments with drugs that reactivate silenced gene expression with secondary agents that target the re-expressed genes and/or reconstituted signal transduction pathways. In this review, we will discuss in detail the mechanisms of gene silencing by DNA methylation, the techniques used to decipher the complement of methylation-inactivated genes in human cancers, and current and future strategies for reactivating the expression of methylation-silenced genes.
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Affiliation(s)
- Adam R Karpf
- Huntsman Cancer Institute, University of Utah, 2000 Circle of Hope, Salt Lake City, Utah, UT 84112, USA.
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28
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Duthie SJ, Narayanan S, Brand GM, Pirie L, Grant G. Impact of folate deficiency on DNA stability. J Nutr 2002; 132:2444S-2449S. [PMID: 12163709 DOI: 10.1093/jn/132.8.2444s] [Citation(s) in RCA: 164] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Convincing evidence links folate deficiency with colorectal cancer incidence. Currently, it is believed that folate deficiency affects DNA stability principally through two potential pathways. 5,10-Methylenetetrahydrofolate donates a methyl group to uracil, converting it to thymine, which is used for DNA synthesis and repair. If folate is limited, imbalances in the DNA precursor pool occur, and uracil may be misincorporated into DNA. Subsequent misincorporation and repair may lead to double strand breaks, chromosomal damage and cancer. Moreover, folate affects gene expression by regulating cellular S-adenosylmethionine (SAM) levels. 5-Methyltetrahydrofolate serves as methyl donor in the remethylation of homocysteine to methionine, which in turn is converted to SAM. SAM methylates specific cytosines in DNA, and this regulates gene transcription. As a consequence of folate deficiency, cellular SAM is depleted, which in turn induces DNA hypomethylation and potentially induces proto-oncogene expression leading to cancer. Data from several model systems supporting these mechanisms are reviewed here. There is convincing evidence that folate modulates both DNA synthesis and repair and DNA hypomethylation with altered gene expression in vitro. The data from in vivo experiments in rodents is more difficult to interpret because of variations in the animal and experimental systems used and the influence of tissue specificity and folate metabolism. Most importantly, the confounding effects of nutrient-gene interactions, together with the identification of polymorphisms in key enzyme systems and the influence that these have on folate metabolism and DNA stability, must be considered when interpreting evidence from human studies.
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Frühwald MC, Plass C. Global and gene-specific methylation patterns in cancer: aspects of tumor biology and clinical potential. Mol Genet Metab 2002; 75:1-16. [PMID: 11825059 DOI: 10.1006/mgme.2001.3265] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Heritable alterations of DNA that do not affect the base pair sequence itself but nevertheless regulate the predetermined activity of genes are referred to as epigenetic. Epigenetic mechanisms comprise diverse phenomena including stable feedback loops, nuclear compartmentalization, differential replication timing, heritable chromatin structures, and, foremost, DNA cytosine methylation (1-3). DNA cytosine methylation has recently gained major attention in the field of basic molecular biology as well as in studies of human diseases including cancer. Changes in DNA methylation patterns in human malignancies have been shown to contribute to carcinogenesis in multiple ways. Both hypo- and hypermethylation events have been described in various neoplasias leading to chromosomal instability and transcriptional gene silencing. DNA methylation research has entered the clinical arena and methylation patterns have become a major focus of clinicians seeking novel prognostic factors and therapeutic targets. The following minireview covers aspects of the basic molecular biology of DNA methylation and summarizes its importance in human cancers.
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Affiliation(s)
- Michael C Frühwald
- Klinik und Poliklinik für Kinderheilkunde, Universitätsklinikum Münster, Albert-Schweitzer-Strasse 33, 48149 Münster, Germany.
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Duthie SJ, Narayanan S, Blum S, Pirie L, Brand GM. Folate deficiency in vitro induces uracil misincorporation and DNA hypomethylation and inhibits DNA excision repair in immortalized normal human colon epithelial cells. Nutr Cancer 2001; 37:245-51. [PMID: 11142099 DOI: 10.1207/s15327914nc372_18] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Epidemiological studies have indicated that folic acid protects against a variety of cancers, particularly cancer of the colorectum. Folate is essential for efficient DNA synthesis and repair. Moreover, folate can affect cellular S-adenosylmethionine levels, which regulate DNA methylation and control gene expression. We have investigated the mechanisms through which folate affects DNA stability in immortalized normal human colonocytes (HCEC). DNA strand breakage, uracil misincorporation, and DNA repair, in response to oxidative and alkylation damage, were determined in folate-sufficient and folate-deficient colonocytes by single cell gel electrophoresis. In addition, methyl incorporation into genomic DNA was measured using the bacterial enzyme Sss1 methylase. Cultured human colonocyte DNA contained endogenous strand breaks and uracil. Folate deficiency significantly increased strand breakage and uracil misincorporation in these cells. This negative effect on DNA stability was concentration dependent at levels usually found in human plasma (1-10 ng/ml). DNA methylation was decreased in HCEC grown in the absence of folate. Conversely, hypomethylation was not concentration dependent. Folate deficiency impaired the ability of HCEC to repair oxidative and alkylation damage. These results demonstrate that folic acid modulates DNA repair, DNA strand breakage, and uracil misincorporation in immortalized human colonocytes and that folate deficiency substantially decreases DNA stability in these cells.
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Affiliation(s)
- S J Duthie
- Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, UK.
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Abstract
DNA methylation is the main epigenetic modification in humans. The methylation of promoter inhibits the transcription in most genes. In normal tissues, isolated CpG dinucleotides in bulk chromatin are often methylated, whereas cytosines in CpG islands are unmethylated. In neoplasms including gastrointestinal cancer, this pattern of methylation is commonly reversed. The alteration of DNA methylation plays a key role in the process of carcinogenesis. The gastrointestinal carcinogenesis is suggested to be associated with the decrease of total genomic DNA methylation; hypomethylation of certain specific oncogenes such as c-myc, c-Ha-ras, c-fos and alpha-fetoprotein; and hypermethylation of the promoter of some tumor suppressor genes containing p16(INK4A), E-cadherin and hMLH1 genes. This review focuses on the analysis methods for methylation, studies for aberrant DNA methylation in gastrointestinal carcinogenesis, and the intervention changing methylation, including the treatment of 5-azacytidine, supplement of folate and gene therapy.
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Affiliation(s)
- J Y Fang
- Shanghai Institute of Digestive Disease, Shanghai Second Medical University, Shanghai, People's Republic of China.
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Cannon RE, Graves S, Spalding JW, Trempus CS, Tennant RW. Oral administration of dimethylvinyl chloride increases frequency of forestomach papillomas in Tg.AC mice. Mol Carcinog 2000; 29:229-35. [PMID: 11170261 DOI: 10.1002/1098-2744(200012)29:4<229::aid-mc1005>3.0.co;2-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
This work was initiated to determine the potential for the Tg.AC mouse model to identify chemical carcinogens by an oral route of administration. Tg.AC v-Ha-ras transgenic mice were exposed to dimethyvinyl chloride (DMVC; 1-chloro-2-methylpropene), a structural analog of the human carcinogen vinyl chloride. In the National Toxicology Program 2-yr bioassay, DMVC induced tumors in the oral, nasal, and gastric epithelia of rats and mice. Initial studies were performed in female Tg.AC mice to determine an appropriate oral dose of DMVC to evaluate the potential for stratified gastric or oral epithelia of Tg.AC mice to serve as a target tissue for a transgene-dependent induced tumorigenic response. DMVC was administered to 13- to14-wk-old Tg.AC mice by gavage at doses of 0, 50, 100, and 200 mg/kg five times a week for 20 wk. The forestomachs of DMVC-treated Tg.AC mice had an increasing number of papillomas, which were associated with an increase in the dose of DMVC. The average numbers of papillomas per mouse per dose were 2.4, 7.6, 14.1, and 12.6 for the 0, 50, 100, and 200-mg/kg dose groups, respectively. The optimum papillomagenic dose of 100 mg/kg DMVC was established and administered for 5, 10, and 15/wk to investigate the kinetics of papilloma induction in Tg.AC mice. The average numbers of papillomas per animal were 1.8, 8.8, and 19.0 at 5, 10, and 15 wk, respectively. Reverse transcription-polymerase chain reaction assays determined that the v-Ha-ras transgene was transcriptionally active in all tumor tissues but not in nontumor tissues. In situ hybridization assays performed in conjunction with bromodeoxyuridine in vivo labeling localized the transgene-expressing cells of the forestomach papillomas to the proliferating cellular component of the tumors, as previously seen in skin papillomas of Tg.AC mice. The present results confirm that DMVC is tumorigenic and that oral routes of administration can be used to rapidly elicit a transgene-associated tumor response in the forestomach of Tg.AC mice.
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Affiliation(s)
- R E Cannon
- Laboratory of Environmental Carcinogenesis and Mutagenesis, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
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