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Jaguva Vasudevan AA, Kreimer U, Schulz WA, Krikoni A, Schumann GG, Häussinger D, Münk C, Goering W. APOBEC3B Activity Is Prevalent in Urothelial Carcinoma Cells and Only Slightly Affected by LINE-1 Expression. Front Microbiol 2018; 9:2088. [PMID: 30233553 PMCID: PMC6132077 DOI: 10.3389/fmicb.2018.02088] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 08/15/2018] [Indexed: 12/20/2022] Open
Abstract
The most common mutational signature in urothelial carcinoma (UC), the most common type of urinary bladder cancer is assumed to be caused by the misdirected activity of APOBEC3 (A3) cytidine deaminases, especially A3A or A3B, which are known to normally restrict the propagation of exogenous viruses and endogenous retroelements such as LINE-1 (L1). The involvement of A3 proteins in urothelial carcinogenesis is unexpected because, to date, UC is thought to be caused by chemical carcinogens rather than viral activity. Therefore, we explored the relationship between A3 expression and L1 activity, which is generally upregulated in UC. We found that UC cell lines highly express A3B and in some cases A3G, but not A3A, and exhibit corresponding cytidine deamination activity in vitro. While we observed evidence suggesting that L1 expression has a weak positive effect on A3B and A3G expression and A3B promoter activity, neither efficient siRNA-mediated knockdown nor overexpression of functional L1 elements affected catalytic activity of A3 proteins consistently. However, L1 knockdown diminished proliferation of a UC cell line exhibiting robust endogenous L1 expression, but had little impact on a cell line with low L1 expression levels. Our results indicate that UC cells express A3B at levels exceeding A3A levels by far, making A3B the prime candidate for causing genomic mutations. Our data provide evidence that L1 activation constitutes only a minor and negligible factor involved in induction or upregulation of endogenous A3 expression in UC.
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Affiliation(s)
- Ananda Ayyappan Jaguva Vasudevan
- Department of Urology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.,Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ulrike Kreimer
- Department of Urology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Wolfgang A Schulz
- Department of Urology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Aikaterini Krikoni
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Gerald G Schumann
- Division of Medical Biotechnology, Paul-Ehrlich-Institut, Langen, Germany
| | - Dieter Häussinger
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Carsten Münk
- Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Wolfgang Goering
- Department of Urology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.,Institute of Pathology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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52
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Ott A, Schnable JC, Yeh CT, Wu L, Liu C, Hu HC, Dalgard CL, Sarkar S, Schnable PS. Linked read technology for assembling large complex and polyploid genomes. BMC Genomics 2018; 19:651. [PMID: 30180802 PMCID: PMC6122573 DOI: 10.1186/s12864-018-5040-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 08/27/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Short read DNA sequencing technologies have revolutionized genome assembly by providing high accuracy and throughput data at low cost. But it remains challenging to assemble short read data, particularly for large, complex and polyploid genomes. The linked read strategy has the potential to enhance the value of short reads for genome assembly because all reads originating from a single long molecule of DNA share a common barcode. However, the majority of studies to date that have employed linked reads were focused on human haplotype phasing and genome assembly. RESULTS Here we describe a de novo maize B73 genome assembly generated via linked read technology which contains ~ 172,000 scaffolds with an N50 of 89 kb that cover 50% of the genome. Based on comparisons to the B73 reference genome, 91% of linked read contigs are accurately assembled. Because it was possible to identify errors with > 76% accuracy using machine learning, it may be possible to identify and potentially correct systematic errors. Complex polyploids represent one of the last grand challenges in genome assembly. Linked read technology was able to successfully resolve the two subgenomes of the recent allopolyploid, proso millet (Panicum miliaceum). Our assembly covers ~ 83% of the 1 Gb genome and consists of 30,819 scaffolds with an N50 of 912 kb. CONCLUSIONS Our analysis provides a framework for future de novo genome assemblies using linked reads, and we suggest computational strategies that if implemented have the potential to further improve linked read assemblies, particularly for repetitive genomes.
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Affiliation(s)
- Alina Ott
- Department of Agronomy, Iowa State University, Ames, IA 50011 USA
- Present address: Roche Sequencing Solutions, 500 S Rosa Road, Madison, WI 53719 USA
| | - James C. Schnable
- Department of Agriculture and Horticulture, University of Nebraska-Lincoln, Lincoln, NE 68588 USA
- Data2Bio LLC, 2079 Roy J Carver Co-Laboratory, 1111 WOI Rd, Ames, IA 50011 USA
- Dryland Genetics LLC, 2073 Roy J Carver Co-Laboratory, 1111 WOI Rd, Ames, IA 50011 USA
| | - Cheng-Ting Yeh
- Department of Agronomy, Iowa State University, Ames, IA 50011 USA
- Data2Bio LLC, 2079 Roy J Carver Co-Laboratory, 1111 WOI Rd, Ames, IA 50011 USA
| | - Linjiang Wu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011 USA
| | - Chao Liu
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011 USA
- Present address: Department of Thermal Engineering, Tsinghua University, Beijing, 100084 China
| | - Heng-Cheng Hu
- The American Genome Center, Uniformed Services University of the Health Sciences, Bethesda, MD 20814 USA
- Collaborative Health Initiative Research Program (CHIRP), Uniformed Services University School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814 USA
- Present address: Qiagen Sciences Inc, 6951 Executive Way, Frederick, MD 21703 USA
| | - Clifton L. Dalgard
- The American Genome Center, Uniformed Services University of the Health Sciences, Bethesda, MD 20814 USA
- Collaborative Health Initiative Research Program (CHIRP), Uniformed Services University School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814 USA
- Department of Anatomy, Physiology and Genetics, Uniformed Services University School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814 USA
| | - Soumik Sarkar
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50011 USA
| | - Patrick S. Schnable
- Department of Agronomy, Iowa State University, Ames, IA 50011 USA
- Data2Bio LLC, 2079 Roy J Carver Co-Laboratory, 1111 WOI Rd, Ames, IA 50011 USA
- Dryland Genetics LLC, 2073 Roy J Carver Co-Laboratory, 1111 WOI Rd, Ames, IA 50011 USA
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53
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Whongsiri P, Pimratana C, Wijitsettakul U, Jindatip D, Sanpavat A, Schulz WA, Hoffmann MJ, Goering W, Boonla C. LINE-1 ORF1 Protein Is Up-regulated by Reactive Oxygen Species and Associated with Bladder Urothelial Carcinoma Progression. Cancer Genomics Proteomics 2018; 15:143-151. [PMID: 29496693 DOI: 10.21873/cgp.20072] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 01/23/2018] [Accepted: 02/01/2018] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND/AIM Reactivation of long interspersed nuclear element-1 (LINE-1) and oxidative stress are suggested to have oncogenic potential to drive tumorigenesis and cancer progression. We previously demonstrated that reactive oxygen species (ROS) caused hypomethylation of LINE-1 elements in bladder cancer cells. In this study, we investigated the expression of LINE-1-encoded protein (ORF1p) and oxidative stress marker 4-hydroxynonenal (4-HNE) in human bladder cancer tissues, as well as induction of ORF1p expression by ROS in bladder cancer cell lines. MATERIALS AND METHODS Thirty-six cancerous and 15 non-cancerous adjacent tissues were immunohistochemically stained for ORF1p and 4-HNE. ORF1p expression and cell migration were determined in bladder cancer cells exposed to H2O2 Results: ORF1p and 4-HNE expression was higher in cancerous than non-cancerous tissues. Elevated ORF1p expression was associated with increased 4-HNE expression and with advanced tumors. H2O2 provoked oxidative stress and up-regulated ORF1p expression in VM-CUB-1 compared to the untreated control, and to a lesser degree in TCCSUP. H2O2 exposure enhanced cell migration in UM-UC-3, TCCSUP and VM-CUB-1. CONCLUSION Elevated ORF1p expression is associated with tumor progression. ROS experimentally induce ORF1p expression and promote migration in bladder cancer cells.
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Affiliation(s)
- Patcharawalai Whongsiri
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | | | | | - Depicha Jindatip
- Department of Anatomy, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Anapat Sanpavat
- Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Wolfgang A Schulz
- Department of Urology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Michèle J Hoffmann
- Department of Urology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Wolfgang Goering
- Department of Pathology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Chanchai Boonla
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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54
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Maugeri A, Barchitta M, Mazzone MG, Giuliano F, Basile G, Agodi A. Resveratrol Modulates SIRT1 and DNMT Functions and Restores LINE-1 Methylation Levels in ARPE-19 Cells under Oxidative Stress and Inflammation. Int J Mol Sci 2018; 19:E2118. [PMID: 30037017 PMCID: PMC6073744 DOI: 10.3390/ijms19072118] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/14/2018] [Accepted: 07/17/2018] [Indexed: 12/13/2022] Open
Abstract
The role of epigenetic alterations in the pathogenesis of retinal degenerative diseases, including age-related macular degeneration (AMD), has been pending so far. Our study investigated the effect of oxidative stress and inflammation on DNA methyltransferases (DNMTs) and Sirtuin 1 (SIRT1) functions, as well as on long interspersed nuclear element-1 (LINE-1) methylation, in human retinal pigment epithelial (ARPE-19) cells. Therefore, we evaluated whether treatment with resveratrol may modulate DNMT and SIRT1 functions and restore changes in LINE-1 methylation. Cells were treated with 25 mU/mL glucose oxidase (GOx) or 10 µg/mL lipopolysaccharide (LPS) to mimic oxidative or inflammatory conditions, respectively. Oxidative stress decreased DNMT1, DNMT3a, DNMT3b, and SIRT1 expression (p-values < 0.05), as well as total DNMTs (-28.5%; p < 0.0001) and SIRT1 (-29.0%; p < 0.0001) activities. Similarly, inflammatory condition decreased DNMT1 and SIRT1 expression (p-values < 0.05), as well as total DNMTs (-14.9%; p = 0.007) and SIRT1 (-20.1%; p < 0.002) activities. Interestingly, GOx- and LPS-treated cells exhibited lower LINE-1 methylation compared to controls (p-values < 0.001). We also demonstrated that treatment with 10 μM resveratrol for 24 h counteracted the detrimental effect on DNMT and SIRT1 functions, and LINE-1 methylation, in cells under oxidative and inflammatory conditions. However, further studies should explore the perspectives of resveratrol as a suitable strategy for the prevention and/or treatment of retinal degenerative diseases.
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Affiliation(s)
- Andrea Maugeri
- Department of Medical and Surgical Sciences and Advanced Technologies "GF Ingrassia", University of Catania, via S. Sofia, 87, 95123 Catania, Italy.
| | - Martina Barchitta
- Department of Medical and Surgical Sciences and Advanced Technologies "GF Ingrassia", University of Catania, via S. Sofia, 87, 95123 Catania, Italy.
| | - Maria Grazia Mazzone
- SIFI SpA, Research and Development Department, Via Ercole Patti 36, 95025 Catania, Italy.
| | - Francesco Giuliano
- SIFI SpA, Research and Development Department, Via Ercole Patti 36, 95025 Catania, Italy.
| | - Guido Basile
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Via Plebiscito, 628, 95124 Catania, Italy.
| | - Antonella Agodi
- Department of Medical and Surgical Sciences and Advanced Technologies "GF Ingrassia", University of Catania, via S. Sofia, 87, 95123 Catania, Italy.
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55
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Curcumin Modulates DNA Methyltransferase Functions in a Cellular Model of Diabetic Retinopathy. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:5407482. [PMID: 30057682 PMCID: PMC6051042 DOI: 10.1155/2018/5407482] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 06/05/2018] [Indexed: 12/12/2022]
Abstract
Hyperglycaemia-induced oxidative stress appears to be involved in the aetiology of diabetic retinopathy (DR), a major public health issue, via altering DNA methylation process. We investigated the effect of hyperglycaemia on retinal DNA methyltransferase (DNMT) expression in diabetic mice, using Gene Expression Omnibus datasets. We also evaluated the effect of curcumin both on high glucose-induced reactive oxygen species (ROS) production and altered DNMT functions, in a cellular model of DR. We observed that three months of hyperglycaemia, in insulin-deficient Ins2Akita mice, decrease DNMT1 and DNMT3a expression levels. In retinal pigment epithelium (RPE) cells, we also demonstrated that high glucose-induced ROS production precedes upregulation of DNMT expression and activity, suggesting that changes in DNMT function could be mediated by oxidative stress via a potential dual effect. The early effect results in decreased DNMT activity, accompanied by the highest ROS production, while long-term oxidative stress increases DNMT activity and DNMT1 expression. Interestingly, treatment with 25 μM curcumin for 6 hours restores ROS production, as well as DNMT functions, altered by the exposure of RPE to acute and chronic high glucose concentration. Our study suggests that curcumin may represent an effective antioxidant compound against DR, via restoring oxidative stress and DNMT functions, though further studies are recommended.
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56
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Giudice A, Crispo A, Grimaldi M, Polo A, Bimonte S, Capunzo M, Amore A, D'Arena G, Cerino P, Budillon A, Botti G, Costantini S, Montella M. The Effect of Light Exposure at Night (LAN) on Carcinogenesis via Decreased Nocturnal Melatonin Synthesis. Molecules 2018; 23:E1308. [PMID: 29844288 PMCID: PMC6100442 DOI: 10.3390/molecules23061308] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/24/2018] [Accepted: 05/29/2018] [Indexed: 12/13/2022] Open
Abstract
In mammals, a master clock is located within the suprachiasmatic nucleus (SCN) of the hypothalamus, a region that receives input from the retina that is transmitted by the retinohypothalamic tract. The SCN controls the nocturnal synthesis of melatonin by the pineal gland that can influence the activity of the clock's genes and be involved in the inhibition of cancer development. On the other hand, in the literature, some papers highlight that artificial light exposure at night (LAN)-induced circadian disruptions promote cancer. In the present review, we summarize the potential mechanisms by which LAN-evoked disruption of the nocturnal increase in melatonin synthesis counteracts its preventive action on human cancer development and progression. In detail, we discuss: (i) the Warburg effect related to tumor metabolism modification; (ii) genomic instability associated with L1 activity; and (iii) regulation of immunity, including regulatory T cell (Treg) regulation and activity. A better understanding of these processes could significantly contribute to new treatment and prevention strategies against hormone-related cancer types.
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Affiliation(s)
- Aldo Giudice
- Epidemiology Unit, IRCCS Istituto Nazionale Tumori "Fondazione G. Pascale", 80131 Napoli, Italy.
| | - Anna Crispo
- Epidemiology Unit, IRCCS Istituto Nazionale Tumori "Fondazione G. Pascale", 80131 Napoli, Italy.
| | - Maria Grimaldi
- Epidemiology Unit, IRCCS Istituto Nazionale Tumori "Fondazione G. Pascale", 80131 Napoli, Italy.
| | - Andrea Polo
- Experimental Pharmacology Unit, IRCCS Istituto Nazionale Tumori "Fondazione G. Pascale", 80131 Napoli, Italy.
| | - Sabrina Bimonte
- Division of Anesthesia and Pain Medicine, IRCCS Istituto Nazionale Tumori "Fondazione G. Pascale", 80131 Napoli, Italy.
| | - Mario Capunzo
- Department of Medicine Surgery and Dentistry, University of Salerno, Baronissi, 84081 Salerno, Italy.
| | - Alfonso Amore
- Abdominal Surgical Oncology and Hepatobiliary Unit, IRCCS Istituto Nazionale Tumori "Fondazione G. Pascale", 80131 Napoli, Italy.
| | - Giovanni D'Arena
- Department of Hematology and Stem Cell Transplantation Unit, IRCCS, Cancer Referral Center of Basilicata, 85028 Rionero in Vulture, Italy.
| | - Pellegrino Cerino
- Istituto Zooprofilattico Sperimentale del Mezzogiorno (IZSM), 80055 Portici, Napoli, Italy.
| | - Alfredo Budillon
- Experimental Pharmacology Unit, IRCCS Istituto Nazionale Tumori "Fondazione G. Pascale", 80131 Napoli, Italy.
| | - Gerardo Botti
- Pathology Unit, IRCCS Istituto Nazionale Tumori "Fondazione G. Pascale", 80131 Napoli, Italy.
| | - Susan Costantini
- Experimental Pharmacology Unit, IRCCS Istituto Nazionale Tumori "Fondazione G. Pascale", 80131 Napoli, Italy.
| | - Maurizio Montella
- Epidemiology Unit, IRCCS Istituto Nazionale Tumori "Fondazione G. Pascale", 80131 Napoli, Italy.
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Nguyen NPD, Deshpande V, Luebeck J, Mischel PS, Bafna V. ViFi: accurate detection of viral integration and mRNA fusion reveals indiscriminate and unregulated transcription in proximal genomic regions in cervical cancer. Nucleic Acids Res 2018; 46:3309-3325. [PMID: 29579309 PMCID: PMC6283451 DOI: 10.1093/nar/gky180] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 02/12/2018] [Accepted: 03/05/2018] [Indexed: 12/20/2022] Open
Abstract
The integration of viral sequences into the host genome is an important driver of tumorigenesis in many viral mediated cancers, notably cervical cancer and hepatocellular carcinoma. We present ViFi, a computational method that combines phylogenetic methods with reference-based read mapping to detect viral integrations. In contrast with read-based reference mapping approaches, ViFi is faster, and shows high precision and sensitivity on both simulated and biological data, even when the integrated virus is a novel strain or highly mutated. We applied ViFi to matched genomic and mRNA data from 68 cervical cancer samples from TCGA and found high concordance between the two. Surprisingly, viral integration resulted in a dramatic transcriptional upregulation in all proximal elements, including LINEs and LTRs that are not normally transcribed. This upregulation is highly correlated with the presence of a viral gene fused with a downstream human element. Moreover, genomic rearrangements suggest the formation of apparent circular extrachromosomal (ecDNA) human-viral structures. Our results suggest the presence of apparent small circular fusion viral/human ecDNA, which correlates with indiscriminate and unregulated expression of proximal genomic elements, potentially contributing to the pathogenesis of HPV-associated cervical cancers. ViFi is available at https://github.com/namphuon/ViFi.
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Affiliation(s)
- Nam-phuong D Nguyen
- Computer Science and Engineering, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - Viraj Deshpande
- Computer Science and Engineering, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - Jens Luebeck
- Bioinformatics and Systems Biology Program, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - Paul S Mischel
- Ludwig Institute for Cancer Research, University of California, San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
- Department of Pathology, University of California, San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
- Moores Cancer Center, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - Vineet Bafna
- Computer Science and Engineering, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, USA
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Inamura K. Colorectal Cancers: An Update on Their Molecular Pathology. Cancers (Basel) 2018; 10:cancers10010026. [PMID: 29361689 PMCID: PMC5789376 DOI: 10.3390/cancers10010026] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 01/17/2018] [Accepted: 01/18/2018] [Indexed: 02/07/2023] Open
Abstract
Colorectal cancers (CRCs) are the third leading cause of cancer-related mortality worldwide. Rather than being a single, uniform disease type, accumulating evidence suggests that CRCs comprise a group of molecularly heterogeneous diseases that are characterized by a range of genomic and epigenomic alterations. This heterogeneity slows the development of molecular-targeted therapy as a form of precision medicine. Recent data regarding comprehensive molecular characterizations and molecular pathological examinations of CRCs have increased our understanding of the genomic and epigenomic landscapes of CRCs, which has enabled CRCs to be reclassified into biologically and clinically meaningful subtypes. The increased knowledge of the molecular pathological epidemiology of CRCs has permitted their evolution from a vaguely understood, heterogeneous group of diseases with variable clinical courses to characteristic molecular subtypes, a development that will allow the implementation of personalized therapies and better management of patients with CRC. This review provides a perspective regarding recent developments in our knowledge of the molecular and epidemiological landscapes of CRCs, including results of comprehensive molecular characterizations obtained from high-throughput analyses and the latest developments regarding their molecular pathologies, immunological biomarkers, and associated gut microbiome. Advances in our understanding of potential personalized therapies for molecularly specific subtypes are also reviewed.
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Affiliation(s)
- Kentaro Inamura
- Division of Pathology, The Cancer Institute, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan.
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59
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Okee M, Bayiyana A, Musubika C, Joloba ML, Ashaba-Katabazi F, Bagaya B, Wayengera M. In Vitro Transduction and Target-Mutagenesis Efficiency of HIV-1 pol Gene Targeting ZFN and CRISPR/Cas9 Delivered by Various Plasmids and/or Vectors: Toward an HIV Cure. AIDS Res Hum Retroviruses 2018; 34:88-102. [PMID: 29183134 DOI: 10.1089/aid.2017.0234] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Efficiency of artificial restriction enzymes toward curing HIV has only been separately examined, using differing delivery vehicles. We compared the in vitro transduction and target-mutagenesis efficiency of consortium plasmid and adenoviral vector delivered HIV-1 pol gene targeting zinc finger nuclease (ZFN) with CRISPR/Cas, Custom-ZFN, CRISPR-Cas-9, and plasmids and vectors (murCTSD_pZFN, pGS-U-gRNA, pCMV-Cas-D01A, Ad5-RGD); cell lines (TZM-bl and ACH-2/J-Lat cells); and the latency reversing agents prostratin, suberoylanilide hydroxamic acid, and phorbol myristate acetate. Cell lines were grown in either Dulbecco's modified Eagle's medium or Roswell Park Memorial Institute with the antibiotics kanamycin, zeocin, and efavirenz. Efficiency was assayed by GFP/luciferase activity and/or validated by yeast MEL1 reporter assay, CEL1 restriction fragment assay, and quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Ad5-RGD vectors had better transduction efficiency than murCTSD and pGS-U-gRNA/pCMV-Cas-D01A plasmids. CRISPR/Cas9 exhibited better target-mutagenesis efficiency relative to ZFN (delivered by either plasmid or Ad5 vector) based on gel electrophoresis of pol gene amplicons within ACH-2 and J-Lat cells. Ad-5-RGD vectors enhanced target mutagenesis of ZFN, relative to murCTSD_pZFN plasmids, to levels of CRISPR/Cas9 plasmids. Similar reduction of luciferase activity among TZM-bl treated with Ad5-ZFN vectors relative to CRISPR/Cas-9 and murCTSD_pZFN plasmids was observed on challenge with HIV-1. qRT-PCR of HIV-1 pol gene transcripts affirmed that Ad5 (RGD) vectors enhanced target mutagenesis of ZFN. Whereas CRISPR/Cas-9 may possess inherent superior target-mutagenesis efficiency; the efficiency of ZFN (off-target toxicity withstanding) can be enhanced by altering delivery vehicle from plasmid to Ad5 (RGD) vectors.
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Affiliation(s)
- Moses Okee
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Alice Bayiyana
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Carol Musubika
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Moses L. Joloba
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Fred Ashaba-Katabazi
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Bernard Bagaya
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Misaki Wayengera
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
- Unit of Genetics and Genomics, Department of Pathology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Kampala, Uganda
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Cao B, Zhou X, Yang W, Ma J, Zhou W, Fan D, Hong L. The role of cell-free DNA in predicting colorectal cancer prognosis. Expert Rev Gastroenterol Hepatol 2018; 12:39-48. [PMID: 28838275 DOI: 10.1080/17474124.2017.1372191] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Colorectal cancer is a cancer of the digestive system with poor prognosis. Cell-free DNA has received much attention with its unique predominance, especially in colorectal cancer. Areas covered: This study has summarized recent advancements and challenges regarding cell-free DNA in predicting CRC prognosis. Furthermore, the authors make predictions on the potential developments concerning cell-free DNA in future prognosis prediction techniques. Expert commentary: Cell-free DNA has the value of predicting CRC prognosis as an important biomarke. Further clinical trials should be performed to promote translating cell-free DNA into clinical applications.
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Affiliation(s)
- Bo Cao
- a The First Brigade of Student , Fourth Military Medical University , Xi'an , China
| | - Xin Zhou
- a The First Brigade of Student , Fourth Military Medical University , Xi'an , China
| | - Wanli Yang
- b State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases , Fourth Military Medical University , Xi'an , China
| | - Jiaojiao Ma
- b State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases , Fourth Military Medical University , Xi'an , China
| | - Wei Zhou
- b State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases , Fourth Military Medical University , Xi'an , China
| | - Daiming Fan
- b State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases , Fourth Military Medical University , Xi'an , China
| | - Liu Hong
- b State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases , Fourth Military Medical University , Xi'an , China
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Hall LL, Byron M, Carone DM, Whitfield TW, Pouliot GP, Fischer A, Jones P, Lawrence JB. Demethylated HSATII DNA and HSATII RNA Foci Sequester PRC1 and MeCP2 into Cancer-Specific Nuclear Bodies. Cell Rep 2017; 18:2943-2956. [PMID: 28329686 DOI: 10.1016/j.celrep.2017.02.072] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 01/03/2017] [Accepted: 02/23/2017] [Indexed: 02/05/2023] Open
Abstract
This study reveals that high-copy satellite II (HSATII) sequences in the human genome can bind and impact distribution of chromatin regulatory proteins and that this goes awry in cancer. In many cancers, master regulatory proteins form two types of cancer-specific nuclear bodies, caused by locus-specific deregulation of HSATII. DNA demethylation at the 1q12 mega-satellite, common in cancer, causes PRC1 aggregation into prominent Cancer-Associated Polycomb (CAP) bodies. These loci remain silent, whereas HSATII loci with reduced PRC1 become derepressed, reflecting imbalanced distribution of UbH2A on these and other PcG-regulated loci. Large nuclear foci of HSATII RNA form and sequester copious MeCP2 into Cancer-Associated Satellite Transcript (CAST) bodies. Hence, HSATII DNA and RNA have an exceptional capacity to act as molecular sponges and sequester chromatin regulatory proteins into abnormal nuclear bodies in cancer. The compartmentalization of regulatory proteins within nuclear structure, triggered by demethylation of "junk" repeats, raises the possibility that this contributes to further compromise of the epigenome and neoplastic progression.
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Affiliation(s)
- Lisa L Hall
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Meg Byron
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Dawn M Carone
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Troy W Whitfield
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA; Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Gayle P Pouliot
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Andrew Fischer
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Peter Jones
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jeanne B Lawrence
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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62
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Zheng Y, Joyce BT, Liu L, Zhang Z, Kibbe WA, Zhang W, Hou L. Prediction of genome-wide DNA methylation in repetitive elements. Nucleic Acids Res 2017; 45:8697-8711. [PMID: 28911103 PMCID: PMC5587781 DOI: 10.1093/nar/gkx587] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 06/28/2017] [Indexed: 12/16/2022] Open
Abstract
DNA methylation in repetitive elements (RE) suppresses their mobility and maintains genomic stability, and decreases in it are frequently observed in tumor and/or surrogate tissues. Averaging methylation across RE in genome is widely used to quantify global methylation. However, methylation may vary in specific RE and play diverse roles in disease development, thus averaging methylation across RE may lose significant biological information. The ambiguous mapping of short reads by and high cost of current bisulfite sequencing platforms make them impractical for quantifying locus-specific RE methylation. Although microarray-based approaches (particularly Illumina's Infinium methylation arrays) provide cost-effective and robust genome-wide methylation quantification, the number of interrogated CpGs in RE remains limited. We report a random forest-based algorithm (and corresponding R package, REMP) that can accurately predict genome-wide locus-specific RE methylation based on Infinium array profiling data. We validated its prediction performance using alternative sequencing and microarray data. Testing its clinical utility with The Cancer Genome Atlas data demonstrated that our algorithm offers more comprehensively extended locus-specific RE methylation information that can be readily applied to large human studies in a cost-effective manner. Our work has the potential to improve our understanding of the role of global methylation in human diseases, especially cancer.
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Affiliation(s)
- Yinan Zheng
- Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.,Division of Health and Biomedical Informatics, Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Brian T Joyce
- Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Lei Liu
- Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Zhou Zhang
- Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.,Division of Health and Biomedical Informatics, Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Warren A Kibbe
- Center for Biomedical Informatics and Information Technology, National Cancer Institute, Rockville, MD 20850, USA
| | - Wei Zhang
- Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Lifang Hou
- Center for Population Epigenetics, Robert H. Lurie Comprehensive Cancer Center and Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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63
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Defective regulation of L1 endogenous retroelements in primary Sjogren's syndrome and systemic lupus erythematosus: Role of methylating enzymes. J Autoimmun 2017; 88:75-82. [PMID: 29074164 DOI: 10.1016/j.jaut.2017.10.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 10/07/2017] [Accepted: 10/08/2017] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To investigate whether altered DNA methylation contributes to the inappropriate expression of LINE-1 (L1) retroelements in primary Sjogren's syndrome (SS) and systemic lupus erythematosus (SLE). METHODS Minor salivary glands (MSG) were obtained from 42 patients with primary SS [23 without adverse predictors for lymphoma development (SS-low risk), 7 SS-high risk and 12 complicated by B-cell lymphoma (SS-lymphoma)] and 17 sicca controls (SC). Additionally, kidney biopsy specimens and PBMCs were obtained from 23 and 73 lupus patients, respectively. Relative mRNA expression was quantified for full-length L1 transcripts, along with mediators of methylation. In an independent set of 44 MSG samples (11 SS-low risk, 10 SS-high risk, 15 SS-lymphoma and 8 SC), methylation levels of the L1 promoter were determined by bisulphite pyrosequencing. RESULTS A strong positive correlation was demonstrated between L1 transcripts and gene products that mediate de novo and constitutive DNA methylation, DNA methyltransferase (DNMT)3B, DNMT1, and methyl CpG binding protein 2 (MeCP2), in both SS MSG and lupus renal tissues. A significant negative correlation was observed between expression of L1 and lymphoid-specific helicase (LSH, encoded by HELLS) in both SS MSG and SLE kidney tissues, as well as between DNMT3A transcripts and L1 expression in SLE kidney tissues and PBMCs. Reduced levels of L1 promoter methylation along with increased DNMT3B, DNMT1, and MeCP2, but reduced LSH levels were detected in SS-low risk patients compared to both SS-lymphoma and SC. The SS-lymphoma group was also characterized by a profound decrease of MeCP2 and DNMT3B compared to SC. CONCLUSION Our data support a contributory role of altered methylation mechanisms in the pathogenesis of systemic autoimmune disorders and related lymphoproliferative processes and suggest that LSH and DNMT3A should be investigated as candidate upstream mediators of decreased L1 promoter methylation and increased L1 expression.
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64
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Han Y, Xu J, Kim J, Wu X, Gu J. LINE-1 methylation in peripheral blood leukocytes and clinical characteristics and prognosis of prostate cancer patients. Oncotarget 2017; 8:94020-94027. [PMID: 29212206 PMCID: PMC5706852 DOI: 10.18632/oncotarget.21511] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 09/18/2017] [Indexed: 11/25/2022] Open
Abstract
Global DNA methylation of long interspersed nucleotide elements (LINE-1) in leukocytes has been suggested to be a risk factor for a few cancers. There has been no report of LINE-1 methylation in leukocytes as a risk factor for aggressive prostate cancer at diagnosis and prognosis after treatments. In this study, we measured the leukocyte DNA methylation of LINE-1 in 795 PCa patients and compared the methylation levels across different clinical subgroups. We then determined the association of LINE-1 methylation in leukocytes with clinicopathological variables at diagnosis using logistic regression analysis and biochemical recurrence in patients receiving active treatments (prostatectomy and radiotherapy) using Cox proportional hazard model after adjusting for age, BMI, smoking status, pack year, D’Amico risk groups, and treatments. Overall, the DNA methylation of LINE-1 was not associated with the risk of being diagnosed with high-risk prostate cancer or the risk of biochemical recurrence upon active treatments. Future studies are warranted to investigate other types of repetitive element methylation and longitudinal changes of global methylation in relation to prostate cancer risk and prognosis.
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Affiliation(s)
- Yuyan Han
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Junfeng Xu
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Jeri Kim
- Department of Genitourinary Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Xifeng Wu
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Jian Gu
- Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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65
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Jeong S, Lee K, Wen X, Kim Y, Cho NY, Jang JJ, Kang GH. Tumoral LINE-1 hypomethylation is associated with poor survival of patients with intrahepatic cholangiocarcinoma. BMC Cancer 2017; 17:588. [PMID: 28851390 PMCID: PMC5576385 DOI: 10.1186/s12885-017-3595-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 08/23/2017] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND DNA methylation changes occurring in cancer cells are featured with both promoter CpG island hypermethylation and diffuse genomic hypomethylation. Long interspersed element-1 (LINE-1) is repeated in an interspersed manner with an estimated 500,000 copies per genome. LINE-1 has its CpG sites of the 5' untranslated region methylated heavily in normal cells and undergoes demethylation in association with cancerization. However, little information is available regarding LINE-1 hypomethylation and its prognostic implication in intrahepatic cholangiocarcinomas. METHODS A total of 172 cases of intrahepatic cholangiocarcinomas were analyzed for their methylation levels at four CpG sites of LINE-1 using bisulfite pyrosequencing. We examined the relation between tumoral LINE-1 methylation level and clinicopathological features, including survival. RESULTS Tumor differentiation, lymphatic invasion, and T stage were associated with a low average methylation level of LINE-1 at the four CpG sites; LINE-1 methylation level tended to be lower in high-grade differentiation, lymphatic emboli, and higher T stage. LINE-1 hypomethylation was significantly linked with lower cancer-specific survival in patients with intrahepatic cholangiocarcinoma and was found to be an independent prognostic parameter. CONCLUSIONS Our findings suggest that tumoral LINE-1 hypomethylation could be a molecular biomarker heralding poor prognosis of patients with intrahepatic cholangiocarcinoma. Our findings need to be validated in further study.
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Affiliation(s)
- Seorin Jeong
- Laboratory of Epigenetics, Cancer Research Institute, Seoul National University College of Medicine, Seoul, South Korea
| | - Kyoungbun Lee
- Department of Pathology, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul, 110-744, South Korea
| | - Xianyu Wen
- Laboratory of Epigenetics, Cancer Research Institute, Seoul National University College of Medicine, Seoul, South Korea.,Department of Pathology, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul, 110-744, South Korea
| | - Younghoon Kim
- Laboratory of Epigenetics, Cancer Research Institute, Seoul National University College of Medicine, Seoul, South Korea.,Department of Pathology, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul, 110-744, South Korea
| | - Nam-Yun Cho
- Laboratory of Epigenetics, Cancer Research Institute, Seoul National University College of Medicine, Seoul, South Korea
| | - Ja-June Jang
- Department of Pathology, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul, 110-744, South Korea
| | - Gyeong Hoon Kang
- Laboratory of Epigenetics, Cancer Research Institute, Seoul National University College of Medicine, Seoul, South Korea. .,Department of Pathology, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul, 110-744, South Korea. .,Laboratory of Epigenetics, Cancer Research Institute, Department of Pathology, Seoul National University College of Medicine, Seoul, Korea.
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66
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Deininger P, Morales ME, White TB, Baddoo M, Hedges DJ, Servant G, Srivastav S, Smither ME, Concha M, DeHaro DL, Flemington EK, Belancio VP. A comprehensive approach to expression of L1 loci. Nucleic Acids Res 2017; 45:e31. [PMID: 27899577 PMCID: PMC5389711 DOI: 10.1093/nar/gkw1067] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/09/2016] [Indexed: 11/14/2022] Open
Abstract
L1 elements represent the only currently active, autonomous retrotransposon in the human genome, and they make major contributions to human genetic instability. The vast majority of the 500 000 L1 elements in the genome are defective, and only a relatively few can contribute to the retrotransposition process. However, there is currently no comprehensive approach to identify the specific loci that are actively transcribed separate from the excess of L1-related sequences that are co-transcribed within genes. We have developed RNA-Seq procedures, as well as a 1200 bp 5΄ RACE product coupled with PACBio sequencing that can identify the specific L1 loci that contribute most of the L1-related RNA reads. At least 99% of L1-related sequences found in RNA do not arise from the L1 promoter, instead representing pieces of L1 incorporated in other cellular RNAs. In any given cell type a relatively few active L1 loci contribute to the 'authentic' L1 transcripts that arise from the L1 promoter, with significantly different loci seen expressed in different tissues.
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Affiliation(s)
- Prescott Deininger
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA.,Department of Epidemiology, Tulane University, New Orleans, LA 70112, USA
| | - Maria E Morales
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA
| | - Travis B White
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA
| | - Melody Baddoo
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA
| | - Dale J Hedges
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA
| | | | - Sudesh Srivastav
- Department of Structural and Cellular Biology, Tulane University, New Orleans, LA 70112, USA
| | | | - Monica Concha
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA.,Department of Biostatistics and Bioinformatics, Tulane University, New Orleans, LA 70112, USA
| | - Dawn L DeHaro
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA.,Department of Pathology, Tulane University, New Orleans, LA 70112, USA
| | - Erik K Flemington
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA.,Department of Biostatistics and Bioinformatics, Tulane University, New Orleans, LA 70112, USA
| | - Victoria P Belancio
- Tulane Cancer Center, Tulane University, New Orleans, LA 70112, USA.,Department of Pathology, Tulane University, New Orleans, LA 70112, USA
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67
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Wedge E, Hansen JW, Garde C, Asmar F, Tholstrup D, Kristensen SS, Munch-Petersen HD, Ralfkiaer E, Brown P, Grønbaek K, Kristensen LS. Global hypomethylation is an independent prognostic factor in diffuse large B cell lymphoma. Am J Hematol 2017; 92:689-694. [PMID: 28378885 DOI: 10.1002/ajh.24751] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/16/2017] [Accepted: 03/28/2017] [Indexed: 12/17/2022]
Abstract
Global hypomethylation has been linked to disease progression in several cancers, but has not been reported for Diffuse Large B Cell Lymphoma (DLBCL). This study aimed to assess global methylation in DLBCL and describe its prognostic value. Mean LINE1 methylation, a validated surrogate measure for global methylation, was measured in DNA from 67 tumor biopsies. Additionally, cell-free circulating DNA (cfDNA) in plasma samples from 74 patients was tested to assess the feasibility of global hypomethylation as a biomarker in liquid biopsies. LINE1 methylation was assessed using a commercially available kit, based on pyrosequencing of PCR amplified bisulfite-treated DNA. Global hypomethylation was detected in a subset of cases and was associated with poor overall survival in both tumor biopsies (P = .001) and cfDNA (P = .009). It was the strongest risk factor in multivariate analysis in both biopsies (HR: 10.65, CI: 2.03-55.81, P = .005) and cfDNA (HR: 11.87, CI: 2.80-50.20, P = .001), outperforming conventional clinical risk factors. Finally, hierarchical cluster analyses were performed for the cfDNA samples using previously published gene-specific methylation data. This analysis shows that global hypomethylation co-occurs with other epigenetic abnormalities, including DAPK1 promoter hypermethylation. In conclusion, we have shown that global hypomethylation is strongly associated with poor survival in DLBCL both when present in tumor biopsy DNA and when detected in plasma cfDNA, and has potential for clinical application as a prognostic biomarker.
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Affiliation(s)
- Eileen Wedge
- Department of Haematology; Rigshospitalet; Copenhagen Denmark
| | | | - Christian Garde
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen
| | - Fazila Asmar
- Department of Haematology; Rigshospitalet; Copenhagen Denmark
| | - Dorte Tholstrup
- Department of Haematology; Rigshospitalet; Copenhagen Denmark
| | | | - Helga D. Munch-Petersen
- Department of Haematology; Rigshospitalet; Copenhagen Denmark
- Department of Pathology; Rigshospitalet; Copenhagen Denmark
| | | | - Peter Brown
- Department of Haematology; Rigshospitalet; Copenhagen Denmark
| | | | - Lasse Sommer Kristensen
- Department of Haematology; Rigshospitalet; Copenhagen Denmark
- Department of Molecular Biology and Genetics; Aarhus University; Aarhus Denmark
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68
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Abstract
The PIWI-interacting RNA (piRNA) pathway is essential for retrotransposon silencing. In piRNA-deficient mice, L1-overexpressing male germ cells exhibit excessive DNA damage and meiotic defects. It remains unknown whether L1 expression simply highlights piRNA deficiency or actually drives the germ-cell demise. Specifically, the sheer abundance of genomic L1 copies prevents reliable quantification of new insertions. Here, we developed a codon-optimized L1 transgene that is controlled by an endogenous mouse L1 promoter. Importantly, DNA methylation dynamics of a single-copy transgene were indistinguishable from those of endogenous L1s. Analysis of Mov10l1-/- testes established that de novo methylation of the L1 transgene required the intact piRNA pathway. Consistent with loss of DNA methylation and programmed reduction of H3K9me2 at meiotic onset, the transgene showed 1,400-fold increase in RNA expression and consequently 70-fold increase in retrotransposition in postnatal day 14 Mov10l1-/- germ cells compared with the wild-type. Analysis of adult Mov10l1-/- germ-cell fractions indicated a stage-specific increase of retrotransposition in the early meiotic prophase. However, extrapolation of the transgene data to endogenous L1s suggests that it is unlikely insertional mutagenesis alone accounts for the Mov10l1-/- phenotype. Indeed, pharmacological inhibition of reverse transcription did not rescue the meiotic defect. Cumulatively, these results establish the occurrence of productive L1 mobilization in the absence of an intact piRNA pathway but leave open the possibility of processes preceding L1 integration in triggering meiotic checkpoints and germ-cell death. Additionally, our data suggest that many heritable L1 insertions originate from individuals with partially compromised piRNA defense.
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69
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Min J, Choi B, Han TS, Lee HJ, Kong SH, Suh YS, Kim TH, Choe HN, Kim WH, Hur K, Yang HK. Methylation Levels of LINE-1 As a Useful Marker for Venous Invasion in Both FFPE and Frozen Tumor Tissues of Gastric Cancer. Mol Cells 2017; 40:346-354. [PMID: 28535662 PMCID: PMC5463043 DOI: 10.14348/molcells.2017.0013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/13/2017] [Accepted: 04/24/2017] [Indexed: 12/20/2022] Open
Abstract
Long interspersed nuclear element-1 (LINE-1) is a retrotransposon that contains a CpG island in its 5'-untranslated region. The CpG island of LINE-1 is often heavily methylated in normal somatic cells, which is associated with poor prognosis in various cancers. DNA methylation can differ between formalin-fixed paraffin-embedded (FFPE) and frozen tissues. Therefore, this study aimed to compare the LINE-1 methylation status between the two tissue-storage conditions in gastric cancer (GC) clinical samples and to evaluate whether LINE-1 can be used as an independent prognostic marker for each tissue-storage type. We analyzed four CpG sites of LINE-1 and examined the methylation levels at these sites in 25 FFPE and 41 frozen GC tissues by quantitative bisulfite pyrosequencing. The LINE-1 methylation status was significantly different between the FFPE and frozen GC tissues (p < 0.001). We further analyzed the clinicopathological features in the two groups separately. In the frozen GC tissues, LINE-1 was significantly hypomethylated in GC tissues compared to their corresponding normal gastric mucosa tissues (p < 0.001), and its methylation status was associated with gender, differentiation state, and lymphatic and venous invasion of GC. In the FFPE GC tissues, the methylation levels of LINE-1 differed according to tumor location and venous invasion of GC. In conclusion, LINE-1 can be used as a useful methylation marker for venous invasion in both FFPE and frozen tumor tissues of GC.
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Affiliation(s)
- Jimin Min
- Cancer Research Institute, Seoul National University College of Medicine, Seoul 03080,
Korea
| | - Boram Choi
- Department of Life Science, Ewha Womans University, Seoul 03760,
Korea
| | - Tae-Su Han
- Biotherapeutics Translational Research Center, Division of Biomedical Science, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141,
Korea
| | - Hyuk-Joon Lee
- Cancer Research Institute, Seoul National University College of Medicine, Seoul 03080,
Korea
- Department of Surgery, Seoul National University College of Medicine, Seoul 03080,
Korea
| | - Seong-Ho Kong
- Department of Surgery, Seoul National University College of Medicine, Seoul 03080,
Korea
| | - Yun-Suhk Suh
- Department of Surgery, Seoul National University College of Medicine, Seoul 03080,
Korea
| | - Tae-Han Kim
- Department of Surgery, Seoul National University College of Medicine, Seoul 03080,
Korea
| | - Hwi-Nyeong Choe
- Department of Nursing, Seoul National University Hospital, Seoul 03080,
Korea
| | - Woo Ho Kim
- Department of Pathology, Seoul National University College of Medicine, Seoul 03080,
Korea
| | - Keun Hur
- Department of Biochemistry and Cell Biology, Cell and Matrix Research Institute, School of Medicine, Kyungpook National University, Daegu 41944,
Korea
| | - Han-Kwang Yang
- Cancer Research Institute, Seoul National University College of Medicine, Seoul 03080,
Korea
- Department of Surgery, Seoul National University College of Medicine, Seoul 03080,
Korea
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70
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Furlan C, Polesel J, Barzan L, Franchin G, Sulfaro S, Romeo S, Colizzi F, Rizzo A, Baggio V, Giacomarra V, Dei Tos AP, Boscolo-Rizzo P, Vaccher E, Dolcetti R, Sigalotti L, Fratta E. Prognostic significance of LINE-1 hypomethylation in oropharyngeal squamous cell carcinoma. Clin Epigenetics 2017; 9:58. [PMID: 28572862 PMCID: PMC5450111 DOI: 10.1186/s13148-017-0357-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 05/18/2017] [Indexed: 01/13/2023] Open
Abstract
Background Inclusion of new biomarkers to improve a personalized treatment approach for oropharyngeal squamous cell carcinoma (OPSCC) is urgently needed. Hypomethylation of the Long interspersed nucleotide element-1 (LINE-1) repetitive elements, a widely accepted surrogate of overall genomic DNA methylation content, was found to be associated with a poor prognosis in several cancers. At present, no studies have investigated the influence of LINE-1 methylation levels on OPSCC relapse. The main goal of this study was the evaluation of the prognostic value of LINE-1 methylation status in predicting early tumor relapse in locally advanced OPSCC. Methods We retrospectively reviewed a cohort of 77 patients with stage III–IVB OPSCC. Methylation of LINE-1 repetitive sequences was evaluated by real-time quantitative methylation-specific PCR in formalin-fixed paraffin-embedded tissues. The prognostic relevance of LINE-1 methylation was assessed by comparing patients who relapsed within 2 years from the end of treatment (cases) with those who did not (controls). Results were validated in an independent cohort of 33 patients with OPSCC. Results With respect to early OPSCC relapse, the mean LINE-1 methylation level was significantly lower in relapsed cases than in control group (p < 0.01). Interestingly, LINE-1 methylation was lower in relapsed cases than in controls in both HPV16-negative and HPV16-positive OPSCC patients, even if statistical significance was reached only for the former group (p = 0.01). LINE-1 methylation levels were also significantly reduced in relapsed cases with respect to the controls in OPSCC current smokers (p = 0.02). Consistently, in HPV16-negative current smokers, OPSCC relapse was significantly associated with decreased levels of LINE-1 methylation (p = 0.02). Using logistic regression model, we found that patients with hypomethylated LINE-1 were associated with a 3.5 higher risk of early relapse than hypermethylated ones (OR = 3.51; 95% CI 1.03–12.00). Adjustment for potential confounders did not substantially change the risk magnitude. Results from the validation cohort confirmed the lower LINE-1 methylation in patients who early relapsed compared to relapse-free patients. Conclusions LINE-1 hypomethylation is associated with higher risk of early relapse in stage III–IVB OPSCC. Further validation in a prospective study is needed for its application in daily clinical practice.
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Affiliation(s)
- Carlo Furlan
- Division of Radiotherapy, Centro di Riferimento Oncologico, IRCCS-National Cancer Institute, Aviano, PN Italy
| | - Jerry Polesel
- Unit of Cancer Epidemiology, Centro di Riferimento Oncologico, IRCCS-National Cancer Institute, Aviano, PN Italy
| | - Luigi Barzan
- Department of Surgery, Centro di Riferimento Oncologico, IRCCS-National Cancer Institute, Aviano, PN Italy
| | - Giovanni Franchin
- Division of Radiotherapy, Centro di Riferimento Oncologico, IRCCS-National Cancer Institute, Aviano, PN Italy
| | - Sandro Sulfaro
- Division of Pathology, General Hospital "S. Maria degli Angeli", Pordenone, Italy
| | - Salvatore Romeo
- Department of Pathology, San Donà di Piave Hospital, San Donà di Piave, Italy
| | - Francesca Colizzi
- Immunopathology and Cancer Biomarkers, Centro di Riferimento Oncologico, IRCCS-National Cancer Institute, Aviano, PN Italy
| | - Aurora Rizzo
- Immunopathology and Cancer Biomarkers, Centro di Riferimento Oncologico, IRCCS-National Cancer Institute, Aviano, PN Italy
| | - Vittorio Baggio
- Department of Radiation Oncology, Treviso Regional Hospital, Treviso, Italy
| | - Vittorio Giacomarra
- Unit of Otolaryngology, General Hospital "S. Maria degli Angeli", Pordenone, Italy
| | | | - Paolo Boscolo-Rizzo
- Department of Neurosciences, ENT Clinic and Regional Center for Head and Neck Cancer, Treviso Regional Hospital, University of Padua, Treviso, Italy
| | - Emanuela Vaccher
- Division of Medical Oncology A, Centro di Riferimento Oncologico, IRCCS-National Cancer Institute, Aviano, PN Italy
| | - Riccardo Dolcetti
- Immunopathology and Cancer Biomarkers, Centro di Riferimento Oncologico, IRCCS-National Cancer Institute, Aviano, PN Italy.,Translational Research Institute, The University of Queensland Diamantina Institute, Brisbane, Australia
| | - Luca Sigalotti
- Immunopathology and Cancer Biomarkers, Centro di Riferimento Oncologico, IRCCS-National Cancer Institute, Aviano, PN Italy.,Institute of Clinical Pathology, University Hospital of Udine, Udine, Italy
| | - Elisabetta Fratta
- Immunopathology and Cancer Biomarkers, Centro di Riferimento Oncologico, IRCCS-National Cancer Institute, Aviano, PN Italy
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Fortunato A, Boddy A, Mallo D, Aktipis A, Maley CC, Pepper JW. Natural Selection in Cancer Biology: From Molecular Snowflakes to Trait Hallmarks. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a029652. [PMID: 28148564 DOI: 10.1101/cshperspect.a029652] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Evolution by natural selection is the conceptual foundation for nearly every branch of biology and increasingly also for biomedicine and medical research. In cancer biology, evolution explains how populations of cells in tumors change over time. It is a fundamental question whether this evolutionary process is driven primarily by natural selection and adaptation or by other evolutionary processes such as founder effects and drift. In cancer biology, as in organismal evolutionary biology, there is controversy about this question and also about the use of adaptation through natural selection as a guiding framework for research. In this review, we discuss the differences and similarities between evolution among somatic cells versus evolution among organisms. We review what is known about the parameters and rate of evolution in neoplasms, as well as evidence for adaptation. We conclude that adaptation is a useful framework that accurately explains the defining characteristics of cancer. Further, convergent evolution through natural selection provides the only satisfying explanation both for how a group of diverse pathologies have enough in common to usefully share the descriptive label of "cancer" and for why this convergent condition becomes life-threatening.
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Affiliation(s)
- Angelo Fortunato
- Biodesign Center for Personalized Diagnostics, and School of Life Sciences, Arizona State University, Tempe, Arizona 85287
| | - Amy Boddy
- Department of Psychology, Arizona State University, Tempe, Arizona 85287
| | - Diego Mallo
- Biodesign Center for Personalized Diagnostics, and School of Life Sciences, Arizona State University, Tempe, Arizona 85287
| | - Athena Aktipis
- Department of Psychology, Arizona State University, Tempe, Arizona 85287.,Biodesign Center for Evolution and Medicine, Arizona State University, Tempe, Arizona 85287
| | - Carlo C Maley
- Biodesign Center for Personalized Diagnostics, and School of Life Sciences, Arizona State University, Tempe, Arizona 85287.,Centre for Evolution and Cancer, Institute of Cancer Research, London SM2 5NG, United Kingdom
| | - John W Pepper
- Biometry Research Group, Division of Cancer Prevention, National Cancer Institute, Rockville, Maryland 20850.,Santa Fe Institute, Santa Fe, New Mexico 87501
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72
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Mita P, Savas JN, Briggs EM, Ha S, Gnanakkan V, Yates JR, Robins DM, David G, Boeke JD, Garabedian MJ, Logan SK. URI Regulates KAP1 Phosphorylation and Transcriptional Repression via PP2A Phosphatase in Prostate Cancer Cells. J Biol Chem 2016; 291:25516-25528. [PMID: 27780869 PMCID: PMC5207251 DOI: 10.1074/jbc.m116.741660] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 10/21/2016] [Indexed: 11/06/2022] Open
Abstract
URI (unconventional prefoldin RPB5 interactor protein) is an unconventional prefoldin, RNA polymerase II interactor that functions as a transcriptional repressor and is part of a larger nuclear protein complex. The components of this complex and the mechanism of transcriptional repression have not been characterized. Here we show that KAP1 (KRAB-associated protein 1) and the protein phosphatase PP2A interact with URI. Mechanistically, we show that KAP1 phosphorylation is decreased following recruitment of PP2A by URI. We functionally characterize the novel URI-KAP1-PP2A complex, demonstrating a role of URI in retrotransposon repression, a key function previously demonstrated for the KAP1-SETDB1 complex. Microarray analysis of annotated transposons revealed a selective increase in the transcription of LINE-1 and L1PA2 retroelements upon knockdown of URI. These data unveil a new nuclear function of URI and identify a novel post-transcriptional regulation of KAP1 protein that may have important implications in reactivation of transposable elements in prostate cancer cells.
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Affiliation(s)
- Paolo Mita
- From the Institute of Systems Genetics and
- the Departments of Biochemistry and Molecular Pharmacology
| | - Jeffrey N Savas
- the Department of Chemical Physiology, Scripps Research Institute, La Jolla, California 92037
| | - Erica M Briggs
- the Departments of Biochemistry and Molecular Pharmacology
| | - Susan Ha
- Urology, and
- the Departments of Biochemistry and Molecular Pharmacology
| | - Veena Gnanakkan
- the Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, and
| | - John R Yates
- the Department of Chemical Physiology, Scripps Research Institute, La Jolla, California 92037
| | - Diane M Robins
- the Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Gregory David
- the Departments of Biochemistry and Molecular Pharmacology
| | - Jef D Boeke
- From the Institute of Systems Genetics and
- the Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, and
- the Departments of Biochemistry and Molecular Pharmacology
| | - Michael J Garabedian
- Urology, and
- Microbiology at New York University School of Medicine, New York, New York 10016
| | - Susan K Logan
- Urology, and
- the Departments of Biochemistry and Molecular Pharmacology
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73
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Desaulniers D, Cummings-Lorbetskie C, Li N, Xiao GH, Marro L, Khan N, Leingartner K. Sodium bisulfite pyrosequencing revealed that developmental exposure to environmental contaminant mixtures does not affect DNA methylation of DNA repeats in Sprague-Dawley rats. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2016; 80:32-52. [PMID: 27905861 DOI: 10.1080/15287394.2016.1231644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/29/2016] [Indexed: 06/06/2023]
Abstract
Hypomethylation of DNA repeats has been linked to diseases and cancer predisposition. Human studies suggest that higher blood concentrations of environmental contaminants (EC) correlate with levels of hypomethylation of DNA repeats in blood. The objective of this study was to examine the effect of in utero and/or lactational exposure to EC on the methylation of DNA repeats (LINE-1 and identifier element) in Sprague-Dawley rat pups at birth, at postnatal day (PND) 21, and in adulthood (PND78-86). From gestation day 0 to PND20, dams were exposed to a mixture "M" of polychlorinated biphenyls (PCB), pesticides, and methylmercury (MeHg), at 0.5 or 1 mg/kg/d (0.5M and M). At birth, some control (C) and M litters were cross-fostered to create the following in utero/postnatal exposure groups: C/C, M/C, C/M, M/M. Additional dams received 1.8 ng/kg/d of a mixture of aryl-hydrocarbon receptor (AhR) agonists (non-ortho-PCB, PC-dibenzodioxins, and PC-dibenzofurans) without or with 0.5M (0.5MAhR). Measurements of EC residue levels confirmed differences in their accumulation across treatments, age, and tissues. Although induction of hepatic detoxification enzyme activities (cytochrome P-450) demonstrated biological effects of treatments, the assessment of methylation in DNA repeats by sodium bisulfite pyrosequencing of liver, spleen, and thymus samples revealed no marked treatment-related effects but significant tissue- and age-related methylation differences. Further studies are required to determine whether absence of significant observable treatment effects on methylation of DNA repeats in the rat relate to tissue, strain, or species differences.
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Affiliation(s)
- Daniel Desaulniers
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Cathy Cummings-Lorbetskie
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Nanqin Li
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Gong-Hua Xiao
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Leonora Marro
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Nasrin Khan
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
| | - Karen Leingartner
- a Health Canada, Healthy Environments and Consumer Safety Branch, Environmental Health Sciences and Research Bureau , Ottawa , Ontario , Canada
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74
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Cook PR, Tabor GT. Deciphering fact from artifact when using reporter assays to investigate the roles of host factors on L1 retrotransposition. Mob DNA 2016; 7:23. [PMID: 27895722 PMCID: PMC5120415 DOI: 10.1186/s13100-016-0079-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 11/04/2016] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND The Long INterspersed Element-1 (L1, LINE-1) is the only autonomous mobile DNA element in humans and has generated as much as half of the genome. Due to increasing clinical interest in the roles of L1 in cancer, embryogenesis and neuronal development, it has become a priority to understand L1-host interactions and identify host factors required for its activity. Apropos to this, we recently reported that L1 retrotransposition in HeLa cells requires phosphorylation of the L1 protein ORF1p at motifs targeted by host cell proline-directed protein kinases (PDPKs), which include the family of mitogen-activated protein kinases (MAPKs). Using two engineered L1 reporter assays, we continued our investigation into the roles of MAPKs in L1 activity. RESULTS We found that the MAPK p38δ phosphorylated ORF1p on three of its four PDPK motifs required for L1 activity. In addition, we found that a constitutively active p38δ mutant appeared to promote L1 retrotransposition in HeLa cells. However, despite the consistency of these findings with our earlier work, we identified some technical concerns regarding the experimental methodology. Specifically, we found that exogenous expression of p38δ appeared to affect at least one heterologous promoter in an engineered L1 reporter, as well as generate opposing effects on two different reporters. We also show that two commercially available non-targeting control (NTC) siRNAs elicit drastically different effects on the apparent retrotransposition reported by both L1 assays, which raises concerns about the use of NTCs as normalizing controls. CONCLUSIONS Engineered L1 reporter assays have been invaluable for determining the functions and critical residues of L1 open reading frames, as well as elucidating many aspects of L1 replication. However, our results suggest that caution is required when interpreting data obtained from L1 reporters used in conjunction with exogenous gene expression or siRNA.
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Affiliation(s)
- Pamela R. Cook
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Drive, Bethesda, MD 20892 USA
| | - G. Travis Tabor
- National Institute of Child Health and Human Development, National Institutes of Health, 35 Convent Drive, Bethesda, MD 20892 USA
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75
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Chuong EB, Elde NC, Feschotte C. Regulatory activities of transposable elements: from conflicts to benefits. Nat Rev Genet 2016; 18:71-86. [PMID: 27867194 DOI: 10.1038/nrg.2016.139] [Citation(s) in RCA: 777] [Impact Index Per Article: 97.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Transposable elements (TEs) are a prolific source of tightly regulated, biochemically active non-coding elements, such as transcription factor-binding sites and non-coding RNAs. Many recent studies reinvigorate the idea that these elements are pervasively co-opted for the regulation of host genes. We argue that the inherent genetic properties of TEs and the conflicting relationships with their hosts facilitate their recruitment for regulatory functions in diverse genomes. We review recent findings supporting the long-standing hypothesis that the waves of TE invasions endured by organisms for eons have catalysed the evolution of gene-regulatory networks. We also discuss the challenges of dissecting and interpreting the phenotypic effect of regulatory activities encoded by TEs in health and disease.
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Affiliation(s)
- Edward B Chuong
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84103, USA
| | - Nels C Elde
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84103, USA
| | - Cédric Feschotte
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84103, USA
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76
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De Luca C, Guadagni F, Sinibaldi-Vallebona P, Sentinelli S, Gallucci M, Hoffmann A, Schumann GG, Spadafora C, Sciamanna I. Enhanced expression of LINE-1-encoded ORF2 protein in early stages of colon and prostate transformation. Oncotarget 2016; 7:4048-61. [PMID: 26716650 PMCID: PMC4826189 DOI: 10.18632/oncotarget.6767] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 11/30/2015] [Indexed: 12/11/2022] Open
Abstract
LINE-1 (L1) retrotransposons are a source of endogenous reverse transcriptase (RT) activity, which is expressed as part of the L1-encoded ORF2 protein (L1-ORF2p). L1 elements are highly expressed in many cancer types, while being silenced in most differentiated somatic tissues. We previously found that RT inhibition reduces cell proliferation and promotes differentiation in neoplastic cells, indicating that high endogenous RT activity promotes cancer growth. Here we investigate the expression of L1-ORF2p in several human types of cancer. We have developed a highly specific monoclonal antibody (mAb chA1-L1) to study ORF2p expression and localization in human cancer cells and tissues. We uncover new evidence for high levels of L1-ORF2p in transformed cell lines and staged epithelial cancer tissues (colon, prostate, lung and breast) while no or only basal ORF2p expression was detected in non-transformed cells. An in-depth analysis of colon and prostate tissues shows ORF2p expression in preneoplastic stages, namely transitional mucosa and prostate intraepithelial neoplasia (PIN), respectively. Our results show that L1-ORF2p is overexpressed in tumor and in preneoplastic colon and prostate tissues; this latter finding suggests that ORF2p could be considered as a potential early diagnostic biomarker.
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Affiliation(s)
| | - Fiorella Guadagni
- Laboratory BioDAT SR Research, IRCCS San Raffaele Pisana, Rome, Italy
| | - Paola Sinibaldi-Vallebona
- Department of Experimental Medicine and Surgery, University "Tor Vergata", Rome, Italy.,Institute of Translational Pharmacology, CNR, Rome, Italy
| | - Steno Sentinelli
- I.F.O. Regina Elena, UOC Pathological Anatomy/Urology, Rome, Italy
| | - Michele Gallucci
- I.F.O. Regina Elena, UOC Pathological Anatomy/Urology, Rome, Italy
| | - Andreas Hoffmann
- Department of Medical Biotechnology, Paul-Ehrlich-Institut, Langen, Germany
| | - Gerald G Schumann
- Department of Medical Biotechnology, Paul-Ehrlich-Institut, Langen, Germany
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77
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Prior S, Miousse IR, Nzabarushimana E, Pathak R, Skinner C, Kutanzi KR, Allen AR, Raber J, Tackett AJ, Hauer-Jensen M, Nelson GA, Koturbash I. Densely ionizing radiation affects DNA methylation of selective LINE-1 elements. ENVIRONMENTAL RESEARCH 2016; 150:470-481. [PMID: 27419368 PMCID: PMC5003736 DOI: 10.1016/j.envres.2016.06.043] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 06/15/2016] [Accepted: 06/27/2016] [Indexed: 05/26/2023]
Abstract
Long Interspersed Nucleotide Element 1 (LINE-1) retrotransposons are heavily methylated and are the most abundant transposable elements in mammalian genomes. Here, we investigated the differential DNA methylation within the LINE-1 under normal conditions and in response to environmentally relevant doses of sparsely and densely ionizing radiation. We demonstrate that DNA methylation of LINE-1 elements in the lungs of C57BL6 mice is dependent on their evolutionary age, where the elder age of the element is associated with the lower extent of DNA methylation. Exposure to 5-aza-2'-deoxycytidine and methionine-deficient diet affected DNA methylation of selective LINE-1 elements in an age- and promoter type-dependent manner. Exposure to densely IR, but not sparsely IR, resulted in DNA hypermethylation of older LINE-1 elements, while the DNA methylation of evolutionary younger elements remained mostly unchanged. We also demonstrate that exposure to densely IR increased mRNA and protein levels of LINE-1 via the loss of the histone H3K9 dimethylation and an increase in the H3K4 trimethylation at the LINE-1 5'-untranslated region, independently of DNA methylation. Our findings suggest that DNA methylation is important for regulation of LINE-1 expression under normal conditions, but histone modifications may dictate the transcriptional activity of LINE-1 in response to exposure to densely IR.
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Affiliation(s)
- Sara Prior
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Isabelle R Miousse
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Etienne Nzabarushimana
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA; Department of Bioinformatics, School of Informatics and Computing, Indiana University, Bloomington, IN 47405, USA
| | - Rupak Pathak
- Division of Radiation Health, Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Charles Skinner
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Kristy R Kutanzi
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Antiño R Allen
- Division of Radiation Health, Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Jacob Raber
- Departments of Behavioral Neuroscience, Neurology, and Radiation Medicine, Division of Neuroscience, ONPRC, Oregon Health & Science University, Portland, OR 97239, USA
| | - Alan J Tackett
- Department of Biochemistry, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Martin Hauer-Jensen
- Division of Radiation Health, Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Gregory A Nelson
- Department of Basic Sciences, Division of Radiation Research, Loma Linda University, Loma Linda, CA 92350, USA
| | - Igor Koturbash
- Department of Environmental and Occupational Health, Fay W. Boozman College of Public Health, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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78
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Liu P, Dong Y, Gu J, Puthiyakunnon S, Wu Y, Chen XG. Developmental piRNA profiles of the invasive vector mosquito Aedes albopictus. Parasit Vectors 2016; 9:524. [PMID: 27686069 PMCID: PMC5041409 DOI: 10.1186/s13071-016-1815-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 09/22/2016] [Indexed: 12/13/2022] Open
Abstract
Background In eukaryotic organisms, Piwi-interacting RNAs (piRNAs) control the activities of mobile genetic elements and ensure genome maintenance. Recent evidence indicates that piRNAs are involved in multiple biological pathways, including transcriptional regulation of protein-coding genes, sex determination and even interactions between host and pathogens. Aedes albopictus is a major invasive species that transmits a number of viral diseases in humans. Ae. albopictus has the largest genome and the highest abundance of repetitive sequences when compared with members that belong to Culicidae with a published genome. Analysis of piRNA profiles will provide a developmental and evolutionary perspective on piRNAs in Ae. albopictus. Methods piRNAs were identified and characterized during the development of Ae. albopictus, and piRNA expression patterns in adult males and females as well as sugar-fed females and blood-fed females were compared. Results Our results reveal that, despite the large genome size of Ae. albopictus, the piRNA pool of Ae. albopictus (1.2 × 107) is smaller than those of Aedes aegypti (1.7 × 107) and Drosophila melanogaster (1.6 × 107). In Ae. albopictus, piRNAs displayed the highest abundance at the embryo stage and the lowest abundance at the pupal stage. Approximately 50 % of the piRNAs mapped to intergenic regions with no known functions. Approximately 30 % of the piRNAs mapped to repetitive elements, and 77.69 % of these repeat-derived piRNAs mapped to Class I TEs; 45.42 % of the observed piRNA reads originated from piRNA clusters, and most of the top 10 highest expressed piRNA clusters and 100 highest expressed piRNAs from each stage displayed biased expression patterns across the developmental stages. All anti-sense-derived piRNAs displayed a preference for uridine at the 5′ end; however, the sense-derived piRNAs showed adenine bias at the tenth nucleotide position and a typical ping-pong signature, suggesting that the biogenesis of piRNAs was conserved throughout development. Our results also show that 962 piRNAs displayed sex-biased expression, and 522 piRNAs showed higher expression in the blood-fed females than in the sugar-fed females. Conclusions Our results suggest that piRNAs, aside from silencing transposable elements in Ae. albopictus, may have a role in other biological pathways. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1815-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Peiwen Liu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Yunqiao Dong
- Reproductive Medical Centre of Guangdong Women and Children Hospital, Guangzhou, Guangdong, 511442, China
| | - Jinbao Gu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China.
| | - Santhosh Puthiyakunnon
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Yang Wu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China
| | - Xiao-Guang Chen
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong, 510515, China.
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79
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Ariumi Y. Guardian of the Human Genome: Host Defense Mechanisms against LINE-1 Retrotransposition. Front Chem 2016; 4:28. [PMID: 27446907 PMCID: PMC4924340 DOI: 10.3389/fchem.2016.00028] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 06/14/2016] [Indexed: 11/13/2022] Open
Abstract
Long interspersed element type 1 (LINE-1, L1) is a mobile genetic element comprising about 17% of the human genome, encoding a newly identified ORF0 with unknown function, ORF1p with RNA-binding activity and ORF2p with endonuclease and reverse transcriptase activities required for L1 retrotransposition. L1 utilizes an endonuclease (EN) to insert L1 cDNA into target DNA, which induces DNA double-strand breaks (DSBs). The ataxia-telangiectasia mutated (ATM) is activated by DSBs and subsequently the ATM-signaling pathway plays a role in regulating L1 retrotransposition. In addition, the host DNA repair machinery such as non-homologous end-joining (NHEJ) repair pathway is also involved in L1 retrotransposition. On the other hand, L1 is an insertional mutagenic agent, which contributes to genetic change, genomic instability, and tumorigenesis. Indeed, high-throughput sequencing-based approaches identified numerous tumor-specific somatic L1 insertions in variety of cancers, such as colon cancer, breast cancer, and hepatocellular carcinoma (HCC). In fact, L1 retrotransposition seems to be a potential factor to reduce the tumor suppressive property in HCC. Furthermore, recent study demonstrated that a specific viral-human chimeric transcript, HBx-L1, contributes to hepatitis B virus (HBV)-associated HCC. In contrast, host cells have evolved several defense mechanisms protecting cells against retrotransposition including epigenetic regulation through DNA methylation and host defense factors, such as APOBEC3, MOV10, and SAMHD1, which restrict L1 mobility as a guardian of the human genome. In this review, I focus on somatic L1 insertions into the human genome in cancers and host defense mechanisms against deleterious L1 insertions.
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Affiliation(s)
- Yasuo Ariumi
- Ariumi Project Laboratory, Center for AIDS Research and International Research Center for Medical Sciences, Kumamoto University Kumamoto, Japan
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80
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Philippe C, Vargas-Landin DB, Doucet AJ, van Essen D, Vera-Otarola J, Kuciak M, Corbin A, Nigumann P, Cristofari G. Activation of individual L1 retrotransposon instances is restricted to cell-type dependent permissive loci. eLife 2016; 5. [PMID: 27016617 PMCID: PMC4866827 DOI: 10.7554/elife.13926] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 03/25/2016] [Indexed: 12/26/2022] Open
Abstract
LINE-1 (L1) retrotransposons represent approximately one sixth of the human genome, but only the human-specific L1HS-Ta subfamily acts as an endogenous mutagen in modern humans, reshaping both somatic and germline genomes. Due to their high levels of sequence identity and the existence of many polymorphic insertions absent from the reference genome, the transcriptional activation of individual genomic L1HS-Ta copies remains poorly understood. Here we comprehensively mapped fixed and polymorphic L1HS-Ta copies in 12 commonly-used somatic cell lines, and identified transcriptional and epigenetic signatures allowing the unambiguous identification of active L1HS-Ta copies in their genomic context. Strikingly, only a very restricted subset of L1HS-Ta loci - some being polymorphic among individuals - significantly contributes to the bulk of L1 expression, and these loci are differentially regulated among distinct cell lines. Thus, our data support a local model of L1 transcriptional activation in somatic cells, governed by individual-, locus-, and cell-type-specific determinants. DOI:http://dx.doi.org/10.7554/eLife.13926.001 Retrotransposons, also known as jumping genes, have invaded the genomes of most living organisms. These fragments of DNA have the ability to move or copy themselves from one location of a chromosome to another. Depending on where they insert themselves, retrotransposons can modify the sequence of nearby genes, which can alter or even abolish their activity. Although these genetic modifications have contributed significantly to the evolution of different species, retrotransposons can also have detrimental effects; for example, by causing new cases of genetic diseases. Adult human cells have a number of mechanisms that work to keep the activity of retrotransposons at a very low level. However, in many types of cancers retrotransposons escape these defense mechanisms and ‘jump’ actively. This is thought to contribute to the development and spread of cancerous tumors. To understand how jumping genes are mobilized, a fundamental question must be answered: is the high jumping gene activity observed in some cell types a result of activating many copies of the retrotransposons, or only a few of them? This question has been difficult to address because there are more than one hundred copies of retrotransposons that could potentially move in humans, many of which have not even been referenced in the human genome map. Furthermore, each copy is almost identical to another one, making it difficult to discriminate between them. Philippe et al. have now developed an approach that can map where individual retrotransposons are located in the genome of normal and cancerous cells and measure how active these jumping genes are. This revealed that only a very restricted number of them are active in any given cell type. Moreover, different subsets of jumping genes are active in different cell types, and their locations in the genome often do not overlap. Thus, whether jumping genes are activated depends on the cell type and their position in the genome. These results are in contrast to the prevalent view that retrotransposons are activated in a more widespread manner across the genome, at least in cancerous cells. Overall, Philippe et al.’s findings pave the way towards characterizing the chromosome regions in which retrotransposons are frequently activated and understanding how they contribute to cancer and other diseases. DOI:http://dx.doi.org/10.7554/eLife.13926.002
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Affiliation(s)
- Claude Philippe
- INSERM U1081, CNRS UMR 7284, Institute for Research on Cancer and Aging of Nice, Nice, France.,Faculty of Medicine, University of Nice-Sophia Antipolis, Nice, France.,FHU OncoAge, University of Nice-Sophia Antipolis, Nice, France
| | - Dulce B Vargas-Landin
- INSERM U1081, CNRS UMR 7284, Institute for Research on Cancer and Aging of Nice, Nice, France.,Faculty of Medicine, University of Nice-Sophia Antipolis, Nice, France.,Ecole Normale Supérieure, Paris, France
| | - Aurélien J Doucet
- INSERM U1081, CNRS UMR 7284, Institute for Research on Cancer and Aging of Nice, Nice, France.,Faculty of Medicine, University of Nice-Sophia Antipolis, Nice, France.,FHU OncoAge, University of Nice-Sophia Antipolis, Nice, France
| | - Dominic van Essen
- INSERM U1081, CNRS UMR 7284, Institute for Research on Cancer and Aging of Nice, Nice, France.,Faculty of Medicine, University of Nice-Sophia Antipolis, Nice, France
| | - Jorge Vera-Otarola
- INSERM U1081, CNRS UMR 7284, Institute for Research on Cancer and Aging of Nice, Nice, France.,Faculty of Medicine, University of Nice-Sophia Antipolis, Nice, France
| | - Monika Kuciak
- INSERM U1081, CNRS UMR 7284, Institute for Research on Cancer and Aging of Nice, Nice, France.,Faculty of Medicine, University of Nice-Sophia Antipolis, Nice, France.,Ecole Normale Supérieure de Lyon, Lyon, France
| | | | - Pilvi Nigumann
- INSERM U1081, CNRS UMR 7284, Institute for Research on Cancer and Aging of Nice, Nice, France.,Faculty of Medicine, University of Nice-Sophia Antipolis, Nice, France
| | - Gaël Cristofari
- INSERM U1081, CNRS UMR 7284, Institute for Research on Cancer and Aging of Nice, Nice, France.,Faculty of Medicine, University of Nice-Sophia Antipolis, Nice, France.,FHU OncoAge, University of Nice-Sophia Antipolis, Nice, France
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81
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Abstract
Although most of non-long terminal repeat (non-LTR) retrotransposons are incorporated in the host genome almost randomly, some non-LTR retrotransposons are incorporated into specific sequences within a target site. On the basis of structural and phylogenetic features, non-LTR retrotransposons are classified into two large groups, restriction enzyme-like endonuclease (RLE)-encoding elements and apurinic/apyrimidinic endonuclease (APE)-encoding elements. All clades of RLE-encoding non-LTR retrotransposons include site-specific elements. However, only two of more than 20 APE-encoding clades, Tx1 and R1, contain site-specific non-LTR elements. Site-specific non-LTR retrotransposons usually target within multi-copy RNA genes, such as rRNA gene (rDNA) clusters, or repetitive genomic sequences, such as telomeric repeats; this behavior may be a symbiotic strategy to reduce the damage to the host genome. Site- and sequence-specificity are variable even among closely related non-LTR elements and appeared to have changed during evolution. In the APE-encoding elements, the primary determinant of the sequence- specific integration is APE itself, which nicks one strand of the target DNA during the initiation of target primed reverse transcription (TPRT). However, other factors, such as interaction between mRNA and the target DNA, and access to the target region in the nuclei also affect the sequence-specificity. In contrast, in the RLE-encoding elements, DNA-binding motifs appear to affect their sequence-specificity, rather than the RLE domain itself. Highly specific integration properties of these site-specific non-LTR elements make them ideal alternative tools for sequence-specific gene delivery, particularly for therapeutic purposes in human diseases.
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82
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Abstract
Transposable elements have had a profound impact on the structure and function of mammalian genomes. The retrotransposon Long INterspersed Element-1 (LINE-1 or L1), by virtue of its replicative mobilization mechanism, comprises ∼17% of the human genome. Although the vast majority of human LINE-1 sequences are inactive molecular fossils, an estimated 80-100 copies per individual retain the ability to mobilize by a process termed retrotransposition. Indeed, LINE-1 is the only active, autonomous retrotransposon in humans and its retrotransposition continues to generate both intra-individual and inter-individual genetic diversity. Here, we briefly review the types of transposable elements that reside in mammalian genomes. We will focus our discussion on LINE-1 retrotransposons and the non-autonomous Short INterspersed Elements (SINEs) that rely on the proteins encoded by LINE-1 for their mobilization. We review cases where LINE-1-mediated retrotransposition events have resulted in genetic disease and discuss how the characterization of these mutagenic insertions led to the identification of retrotransposition-competent LINE-1s in the human and mouse genomes. We then discuss how the integration of molecular genetic, biochemical, and modern genomic technologies have yielded insight into the mechanism of LINE-1 retrotransposition, the impact of LINE-1-mediated retrotransposition events on mammalian genomes, and the host cellular mechanisms that protect the genome from unabated LINE-1-mediated retrotransposition events. Throughout this review, we highlight unanswered questions in LINE-1 biology that provide exciting opportunities for future research. Clearly, much has been learned about LINE-1 and SINE biology since the publication of Mobile DNA II thirteen years ago. Future studies should continue to yield exciting discoveries about how these retrotransposons contribute to genetic diversity in mammalian genomes.
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83
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Sciamanna I, De Luca C, Spadafora C. The Reverse Transcriptase Encoded by LINE-1 Retrotransposons in the Genesis, Progression, and Therapy of Cancer. Front Chem 2016; 4:6. [PMID: 26904537 PMCID: PMC4749692 DOI: 10.3389/fchem.2016.00006] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 01/26/2016] [Indexed: 12/24/2022] Open
Abstract
In higher eukaryotic genomes, Long Interspersed Nuclear Element 1 (LINE-1) retrotransposons represent a large family of repeated genomic elements. They transpose using a reverse transcriptase (RT), which they encode as part of the ORF2p product. RT inhibition in cancer cells, either via RNA interference-dependent silencing of active LINE-1 elements, or using RT inhibitory drugs, reduces cancer cell proliferation, promotes their differentiation and antagonizes tumor progression in animal models. Indeed, the non-nucleoside RT inhibitor efavirenz has recently been tested in a phase II clinical trial with metastatic prostate cancer patients. An in-depth analysis of ORF2p in a mouse model of breast cancer showed ORF2p to be precociously expressed in precancerous lesions and highly abundant in advanced cancer stages, while being barely detectable in normal breast tissue, providing a rationale for the finding that RT-expressing tumors are therapeutically sensitive to RT inhibitors. We summarize mechanistic and gene profiling studies indicating that abundant LINE-1-derived RT can “sequester” RNA substrates for reverse transcription in tumor cells, entailing the formation of RNA:DNA hybrid molecules and impairing the overall production of regulatory miRNAs, with a global impact on the cell transcriptome. Based on these data, LINE-1-ORF2 encoded RT has a tumor-promoting potential that is exerted at an epigenetic level. We propose a model whereby LINE1-RT drives a previously unrecognized global regulatory process, the deregulation of which drives cell transformation and tumorigenesis with possible implications for cancer cell heterogeneity.
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Affiliation(s)
| | | | - Corrado Spadafora
- Institute of Translational Pharmacology, National Resarch Council of Italy Rome, Italy
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84
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Abstract
Cancer cells have the unusual capacity to limit the cost of the mutation load that they harbor and simultaneously harness its evolutionary potential. This property fuels drug resistance, a key failure mode in oncogene-directed therapy. However, the factors that regulate this capacity might also provide an Achilles' heel that could be exploited therapeutically. Recently, insight has come from a seemingly distant field: protein folding. It is now clear that protein homeostasis broadly supports malignancy and fuels the rapid evolution of drug resistance. Among protein homeostatic mechanisms that influence cancer biology, the essential ATP-driven molecular chaperone heat-shock protein 90 (Hsp90) is especially important. Hsp90 catalyzes folding of many proteins that regulate growth and development. These "client" kinases, transcription factors, and ubiquitin ligases often play critical roles in human disease, especially cancer. Studies in a wide range of systems-from single-celled organisms to human tumor samples-suggest that Hsp90 can broadly reshape the map between genotype and phenotype, acting as a "capacitor" and "potentiator" of genetic variation. Indeed, it has likely done so to such a degree that it has left an impress on diverse genome sequences. Hsp90 can constitute as much as 5% of total protein in transformed cells and increased levels of heat-shock activation correlate with poor prognosis in breast cancer. These findings and others have motivated a flurry of interest in Hsp90 inhibitors as cancer therapeutics, which have met with rather limited success as single agents, but may eventually prove invaluable in limiting the emergence of resistance to other chemotherapeutics, both genotoxic and molecularly targeted. Here, we provide an overview of Hsp90 function, review its relationship to genetic variation and the evolution of new traits, and discuss the importance of these findings for cancer biology and future efforts to drug this pathway.
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Affiliation(s)
- Daniel Jarosz
- Chemical & Systems Biology, Stanford University School of Medicine, Stanford, California, USA; Developmental Biology, Stanford University School of Medicine, Stanford, California, USA.
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85
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Dhivya S, Premkumar K. Nomadic genetic elements contribute to oncogenic translocations: Implications in carcinogenesis. Crit Rev Oncol Hematol 2015; 98:81-93. [PMID: 26548742 DOI: 10.1016/j.critrevonc.2015.10.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 10/05/2015] [Accepted: 10/27/2015] [Indexed: 12/22/2022] Open
Abstract
Chromosomal translocations as molecular signatures have been reported in various malignancies but, the mechanism behind which is largely unknown. Swapping of chromosomal fragments occurs by induction of double strand breaks (DSBs), most of which were initially assumed de novo. However, decoding of human genome proved that transposable elements (TE) might have profound influence on genome integrity. TEs are highly conserved mobile genetic elements that generate DSBs, subsequently resulting in large chromosomal rearrangements. Previously TE insertions were thought to be harmless, but recently gains attention due to the origin of spectrum of post-insertional genomic alterations and subsequent transcriptional alterations leading to development of deleterious effects mainly carcinogenesis. Though the existing knowledge on the cancer-associated TE dynamics is very primitive, exploration of underlying mechanism promises better therapeutic strategies for cancer. Thus, this review focuses on the prevalence of TE in the genome, associated genomic instability upon transposition activation and impact on tumorigenesis.
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Affiliation(s)
- Sridaran Dhivya
- Cancer Genetics and Nanomedicine Laboratory, Department of Biomedical Science, School of Basic Medical Sciences, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India
| | - Kumpati Premkumar
- Cancer Genetics and Nanomedicine Laboratory, Department of Biomedical Science, School of Basic Medical Sciences, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India.
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86
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Kloypan C, Srisa-art M, Mutirangura A, Boonla C. LINE-1 hypomethylation induced by reactive oxygen species is mediated via depletion of S-adenosylmethionine. Cell Biochem Funct 2015; 33:375-85. [PMID: 26178977 DOI: 10.1002/cbf.3124] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 05/27/2015] [Accepted: 06/08/2015] [Indexed: 01/06/2023]
Abstract
Whether long interspersed nuclear element-1 (LINE-1) hypomethylation induced by reactive oxygen species (ROS) was mediated through the depletion of S-adenosylmethionine (SAM) was investigated. Bladder cancer (UM-UC-3 and TCCSUP) and human kidney (HK-2) cell lines were exposed to 20 μM H2O2 for 72 h to induce oxidative stress. Level of LINE-1 methylation, SAM and homocysteine (Hcy) was measured in the H2O2 -exposed cells. Effects of α-tocopheryl acetate (TA), N-acetylcysteine (NAC), methionine, SAM and folic acid on oxidative stress and LINE-1 methylation in the H2O2 -treated cells were explored. Viabilities of cells treated with H2O2 were not significantly changed. Intracellular ROS production and protein carbonyl content were significantly increased, but LINE-1 methylation was significantly decreased in the H2O2 -treated cells. LINE-1 methylation was restored by TA, NAC, methionine, SAM and folic acid. SAM level in H2O2 -treated cells was significantly decreased, while total glutathione was significantly increased. SAM level in H2O2 -treated cells was restored by NAC, methionine, SAM and folic acid; while, total glutathione level was normalized by TA and NAC. Hcy was significantly decreased in the H2O2 -treated cells and subsequently restored by NAC. In conclusion, in bladder cancer and normal kidney cells exposed to H2O2 , SAM and Hcy were decreased, but total glutathione was increased. Treatments with antioxidants (TA and NAC) and one-carbon metabolites (SAM, methionine and folic acid) restored these changes. This pioneer finding suggests that exposure of cells to ROS activates glutathione synthesis via the transsulfuration pathway leading to deficiency of Hcy, which consequently causes SAM depletion and eventual hypomethylation of LINE-1.
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Affiliation(s)
- Chiraphat Kloypan
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Monpicha Srisa-art
- Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
| | - Apiwat Mutirangura
- Department of Anatomy, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Chanchai Boonla
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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87
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Sciamanna I, Gualtieri A, Piazza PF, Spadafora C. Regulatory roles of LINE-1-encoded reverse transcriptase in cancer onset and progression. Oncotarget 2015; 5:8039-51. [PMID: 25478632 PMCID: PMC4226666 DOI: 10.18632/oncotarget.2504] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
LINE-1 retrotransposons encode the reverse transcriptase (RT) enzyme, required for their own mobility, the expression of which is inhibited in differentiated tissues while being active in tumors. Experimental evidence indicate that the inhibition of LINE-1-derived RT restores differentiation in cancer cells, inhibits tumor progression and yields globally reprogrammed transcription profiles. Newly emerging data suggest that LINE-1-encoded RT modulates the biogenesis of miRNAs, by governing the balance between the production of regulatory double-stranded RNAs and RNA:DNA hybrid molecules, with a direct impact on global gene expression. Abnormally high RT activity unbalances the transcriptome in cancer cells, while RT inhibition restores ‘normal’ miRNA profiles and their regulatory networks. This RT-dependent mechanism can target the myriad of transcripts - both coding and non-coding, sense and antisense - in eukaryotic transcriptomes, with a profound impact on cell fates. LINE-1-encoded RT emerges therefore as a key regulator of a previously unrecognized mechanism in tumorigenesis
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88
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Karimi A, Majidzadeh-A K, Madjd Z, Akbari A, Habibi L, Akrami SM. Effect of Copper Sulfate on Expression of Endogenous L1 Retrotransposons in HepG2 Cells (Hepatocellular Carcinoma). Biol Trace Elem Res 2015; 165:131-4. [PMID: 25663478 DOI: 10.1007/s12011-015-0256-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 01/25/2015] [Indexed: 12/26/2022]
Abstract
The long interspersed element-1 (LINE-1 or L1) constitutes approximately 17% of human genome. The expression of these elements is deregulated upon exposure to environmental exposures resulting to genomic instability and cancer promotion. The effect of copper as essential elements in regulation of L1 expression remained to be elucidated. Using non-cytotoxic concentrations of the copper, the expression of endogenous L1 was analyzed by qPCR after 6 days of copper pretreatment in human hepatocellular carcinoma cells (HepG2). The results indicated that the expression of active L1 elements are significantly downregulated at concentrations of 12.5, 25, and 50 μM (p < 0.005). Our data imply that low-level copper exposure may have a protective effect to suppress the induction of L1 activity and decrease incidence of cancer-associated L1 mutagenesis. If this achievement is confirmed by further studies, it can be applied in the long-term goals of cancer prevention.
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Affiliation(s)
- Abbas Karimi
- Tasnim Biotechnology Research Center (TBRC), Faculty of Medicine, AJA University of Medical Sciences, Etemadzadeh Ave., West Fatemi, Tehran, Iran
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89
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Lou YT, Chen CW, Fan YC, Chang WC, Lu CY, Wu IC, Hsu WH, Huang CW, Wang JY. LINE-1 Methylation Status Correlates Significantly to Post-Therapeutic Recurrence in Stage III Colon Cancer Patients Receiving FOLFOX-4 Adjuvant Chemotherapy. PLoS One 2015; 10:e0123973. [PMID: 25919688 PMCID: PMC4412676 DOI: 10.1371/journal.pone.0123973] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 02/24/2015] [Indexed: 12/19/2022] Open
Abstract
Background Methylation levels of long interspersed nucleotide elements (LINE-1) are representative of genome-wide methylation status and crucial in maintaining genomic stability and expression. Their prognostic impact on colon cancer patients receiving adjuvant chemotherapy has not been well established. We evaluated the association between LINE-1 methylation status and clinicopathologic features and postoperative oncological outcomes in stage III colon cancer patients. Materials and Methods 129 UICC stage III colon cancer patients who had received radical resection and FOLFOX adjuvant chemotherapy were enrolled. Global methylation was estimated by analyzing tumor LINE-1 methylation status using bisulfite-polymerase chain reaction (PCR) and pyrosequencing assay. Demographics, clinicopathological data, and postoperative outcomes were recorded by trained abstractors. Outcome measurements included postoperative recurrence and disease-free survival. Univariate, multivariate, and survival analyses were conducted to identify prognostic factors of oncological outcomes. Results The LINE-1 methylation of all 129 patients was measured on a 0–100 scale (mean 63.3; median 63.7, standard deviation 7.1), LINE-1 hypomethylation was more common in patients aged 65 years and above (61.7%±7.6% vs. 64.6±6.4, p=0.019) and those with post-therapeutic recurrence (61.7±7.4 vs 64.3±6.7, p=0.041). Considering risk adjustment, LINE-1 hypomethylation was found to be an independent risk factor of post-therapeutic recurrence (Adjusted OR=14.1, p=0.012). Kaplan-Meier analysis indicated that patients in the low methylation group had shorter period of disease free survival (p=0.01). In a stratified analysis that included 48 patients with post-therapeutic recurrence, it was found that those who experienced shorter period of disease free survival (≦6 months) appeared to have lower LINE-1 methylation levels than patients who reported of recurrence after 6 months (56.68±15.75 vs. 63.55±7.57, p=0.041) Conclusion There was a significantly greater risk of early postoperative recurrence and a shorter period of disease-free survival in Stage III colon cancer patients exhibiting LINE-1 hypomethylation status after being treated with radical resection and FOLFOX chemotherapy.
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Affiliation(s)
- Yun-Ting Lou
- Graduate Institute of Genomic Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Ophthalmology, E-DA Hospital, I-Shou University, Kaohsiung, Taiwan
| | - Chao-Wen Chen
- Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Surgery, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Emergency Medicine, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yun-Ching Fan
- Graduate Institute of Genomic Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Wei-Chiao Chang
- Graduate Institute of Genomic Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
- Department of Pharmacy, Taipei Medical University-Wanfang Hospital, Taipei, Taiwan
- Cancer Center, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Master Program for Clinical Pharmacogenomics and Pharmacoproteomics, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Chien-Yu Lu
- Department of Internal Medicine, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - I-Chen Wu
- Department of Internal Medicine, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Wen-Hung Hsu
- Department of Internal Medicine, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Ching-Wen Huang
- Division of Gastrointestinal and General Surgery, Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jaw-Yuan Wang
- Graduate Institute of Genomic Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Pharmacy, Taipei Medical University-Wanfang Hospital, Taipei, Taiwan
- Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Division of Gastrointestinal and General Surgery, Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Center for Biomarkers and Biotech Drugs, Kaohsiung Medical University, Kaohsiung, Taiwan
- * E-mail:
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90
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Kim WJ, Wittner BS, Amzallag A, Brannigan BW, Ting DT, Ramaswamy S, Maheswaran S, Haber DA. The WTX Tumor Suppressor Interacts with the Transcriptional Corepressor TRIM28. J Biol Chem 2015; 290:14381-90. [PMID: 25882849 DOI: 10.1074/jbc.m114.631945] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Indexed: 02/05/2023] Open
Abstract
WTX encodes a tumor suppressor implicated in the pediatric kidney cancer Wilms tumor and in mesenchymal differentiation with potentially distinct functions in the cytoplasm, at the plasma membrane, and in the nucleus. Although modulating components of the WNT signaling pathway is a proposed function for cytoplasmic and membrane-bound WTX, its nuclear properties are not well understood. Here we report that the transcriptional corepressor TRIM28 is the major binding partner for nuclear WTX. WTX interacted with the coiled coil domain of TRIM28 required for its binding to Krüppel-associated box domains of transcription factors and for its chromatin recruitment through its own coiled coil and proline-rich domains. Knockdown of endogenous WTX reduced the recruitment of TRIM28 to a chromatinized reporter sequence and its ability to repress a target transcript. In mouse embryonic stem cells where TRIM28 plays a major role in repressing endogenous retroviruses and long interspersed elements, knockdown of either TRIM28 or WTX combined with single molecule RNA sequencing revealed a highly significant shared set of differentially regulated transcripts, including derepression of non-coding repetitive sequences and their neighboring protein encoding genes (p < 1e-20). In mesenchymal precursor cells, depletion of WTX and TRIM28 resulted in analogous β-catenin-independent defects in adipogenic and osteogenic differentiation, and knockdown of WTX reduced TRIM28 binding to Pparγ promoter. Together, the physical and functional interaction between WTX and TRIM28 suggests that the nuclear fraction of WTX plays a role in epigenetic silencing, an effect that may contribute to its function as a regulator of cellular differentiation and tumorigenesis.
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Affiliation(s)
- Woo Jae Kim
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts 02129 and
| | - Ben S Wittner
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts 02129 and
| | - Arnaud Amzallag
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts 02129 and
| | - Brian W Brannigan
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts 02129 and
| | - David T Ting
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts 02129 and From the Departments of Medicine and
| | - Sridhar Ramaswamy
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts 02129 and From the Departments of Medicine and
| | - Shyamala Maheswaran
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts 02129 and Surgery
| | - Daniel A Haber
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Charlestown, Massachusetts 02129 and From the Departments of Medicine and Howard Hughes Medical Institute, Chevy Chase, Maryland 20815
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91
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Brooks WH, Renaudineau Y. Epigenetics and autoimmune diseases: the X chromosome-nucleolus nexus. Front Genet 2015; 6:22. [PMID: 25763008 PMCID: PMC4329817 DOI: 10.3389/fgene.2015.00022] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 01/16/2015] [Indexed: 12/18/2022] Open
Abstract
Autoimmune diseases occur more often in females, suggesting a key role for the X chromosome. X chromosome inactivation, a major epigenetic feature in female cells that provides dosage compensation of X-linked genes to avoid overexpression, presents special vulnerabilities that can contribute to the disease process. Disruption of X inactivation can result in loss of dosage compensation with expression from previously sequestered genes, imbalance of gene products, and altered endogenous material out of normal epigenetic context. In addition, the human X has significant differences compared to other species and these differences can contribute to the frequency and intensity of the autoimmune disease in humans as well as the types of autoantigens encountered. Here a link is demonstrated between autoimmune diseases, such as systemic lupus erythematosus, and the X chromosome by discussing cases in which typically non-autoimmune disorders complicated with X chromosome abnormalities also present lupus-like symptoms. The discussion is then extended to the reported spatial and temporal associations of the inactive X chromosome with the nucleolus. When frequent episodes of cellular stress occur, the inactive X chromosome may be disrupted and inadvertently become involved in the nucleolar stress response. Development of autoantigens, many of which are at least transiently components of the nucleolus, is then described. Polyamines, which aid in nucleoprotein complex assembly in the nucleolus, increase further during cell stress, and appear to have an important role in the autoimmune disease process. Autoantigenic endogenous material can potentially be stabilized by polyamines. This presents a new paradigm for autoimmune diseases: that many are antigen-driven and the autoantigens originate from altered endogenous material due to episodes of cellular stress that disrupt epigenetic control. This suggests that epigenetics and the X chromosome are important aspects of autoimmune diseases.
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Affiliation(s)
- Wesley H Brooks
- Department of Chemistry, University of South Florida Tampa, FL, USA
| | - Yves Renaudineau
- Research Unit INSERM ERI29/EA2216, SFR ScinBios, Labex Igo "Immunotherapy Graft, Oncology", Réseau Épigénétique et Réseau Canaux Ioniques du Cancéropole Grand Ouest, European University of Brittany Brest, France ; Laboratory of Immunology and Immunotherapy, Hôpital Morvan Brest, France
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92
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Microsatellite instability in gallbladder carcinoma. Virchows Arch 2015; 466:393-402. [PMID: 25680569 DOI: 10.1007/s00428-015-1720-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 01/06/2015] [Accepted: 01/19/2015] [Indexed: 01/28/2023]
Abstract
The genetic abnormalities involved in the pathogenesis of gallbladder carcinoma (GBC) remain unclear. Microsatellite instability (MSI) has been described in many carcinomas, but little is known about the significance of mismatch repair in gallbladder carcinogenesis. Additionally, methylation status of long interspersed element-1 (LINE-1), a surrogate marker of global DNA methylation, has defined distinct subsets of other cancer types but has not been explored in GBC. Immunohistochemical expression of MSH2, MSH6, MLH1, and PMS2 and LINE-1 mRNA in situ hybridization was evaluated in 67 primary and 15 metastatic GBCs from 77 patients. Amplification of human epidermal growth factor receptor 2 (HER2) was evaluated by fluorescence in situ hybridization. Genotyping for 24 genes involved in carcinogenesis was performed using a multiplex PCR-based platform. MSI was present in 6 of 77 GBCs (7.8 %). Loss of MSH2/MSH6 was detected in five cases and loss of MLH1/PMS2 in one case. MSI status was not associated with Lynch syndrome, tumor grade, extracellular mucin, or tumor-infiltrating lymphocytes. There was no significant difference in mean overall survival of patients with and without MSI. Strong LINE-1 staining was identified in none of the GBC with MSI and in 36 of 69 (52 %) of those without MSI (p = 0.005), suggesting that LINE-1 in the former cohort was hypermethylated. All MSI tumors were negative for HER2 amplification, and TP53 and NRAS mutations were only found in GBC without MSI. MSI was identified in a minority of GBC cases. The strong correlation between global DNA methylation as measured by LINE-1 and loss of mismatch repair proteins suggests that methylation may account for the loss of these proteins. These hypermethylated tumors appear to represent a genetically unique cohort of gallbladder neoplasms, and the data suggests that demethylating agents may have a therapeutic value in this class of tumors.
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93
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Spadafora C. A LINE-1-encoded reverse transcriptase-dependent regulatory mechanism is active in embryogenesis and tumorigenesis. Ann N Y Acad Sci 2015; 1341:164-71. [PMID: 25586649 DOI: 10.1111/nyas.12637] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
LINE-1 (long interspersed nuclear elements) retrotransposons constitute a large family of retrotransposable elements, accounting for 17% of the human genome. They encode proteins required for their own mobilization, including a reverse transcriptase (RT) enzyme highly expressed in mouse embryos and mouse and human cancer cells and repressed in somatic differentiated healthy cells. We have found that reverse transcription takes place in early murine embryos, yielding an increase in LINE-1 copy number during preimplantation development, which also occurs in tumor progression. RT inhibition irreversibly arrests embryo development, reduces cancer cell proliferation, promotes differentiation, antagonizes tumor growth, and causes a global reprogramming of transcription profiles. These results strongly suggest that a previously unrecognized RT-dependent regulatory mechanism operates during preimplantation development, is repressed during differentiation to normal tissues, and, when erroneously reactivated in adult life, promotes cell transformation and cancer progression by "resurrecting" embryonic transcriptional pathways. The RT-dependent mechanism emerges as a major source of genetic and epigenetic changes with physiological, pathological, and evolutionary implications.
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Affiliation(s)
- Corrado Spadafora
- Istituto Superiore di Sanità, Rome, Italy; CNR Institute of Translational Pharmacology, Rome, Italy
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94
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Pitkänen E, Cajuso T, Katainen R, Kaasinen E, Välimäki N, Palin K, Taipale J, Aaltonen LA, Kilpivaara O. Frequent L1 retrotranspositions originating from TTC28 in colorectal cancer. Oncotarget 2015; 5:853-9. [PMID: 24553397 PMCID: PMC3996660 DOI: 10.18632/oncotarget.1781] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
L1 element retrotranspositions have been found to alter expression of genes neighboring the insertion sites, potentially involving them in tumorigenesis and tumor progression. In colorectal cancer (CRC), L1 insertions have been found to target genes with a role in tumorigenesis. Structural changes such as L1 insertions are identifiable by whole genome sequencing (WGS). In this study, we observed frequent somatic L1 retrotranspositions originating from TTC28 using deep coverage WGS data from 92 CRC tumor-normal sample pairs. In two cases the event had targeted NOVA1 gene (p=0.025). In addition, a germline retrotransposition event from TTC28 to GABRA4 was found to be a common polymorphism in the Finnish population. Thus while some events may be tumorigenic, others are likely to be neutral. Our data contradict a recent study where a similar signal in TTC28 was interpreted as a common inactivating translocation. While much work remains to be performed to understand the biological significance of retrotranspositions in cancer, accurate identification of these events is a prerequisite for success.
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Affiliation(s)
- Esa Pitkänen
- Genome-Scale Biology Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland
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95
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Zhao N, Bell DA, Maity A, Staicu AM, Joubert BR, London SJ, Wu MC. Global analysis of methylation profiles from high resolution CpG data. Genet Epidemiol 2014; 39:53-64. [PMID: 25537884 DOI: 10.1002/gepi.21874] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 10/09/2014] [Accepted: 10/31/2014] [Indexed: 12/22/2022]
Abstract
New high throughput technologies are now enabling simultaneous epigenetic profiling of DNA methylation at hundreds of thousands of CpGs across the genome. A problem of considerable practical interest is identification of large scale, global changes in methylation that are associated with environmental variables, clinical outcomes, or other experimental conditions. However, there has been little statistical research on methods for global methylation analysis using technologies with individual CpG resolution. To address this critical gap in the literature, we develop a new strategy for global analysis of methylation profiles using a functional regression approach wherein we approximate either the density or the cumulative distribution function (CDF) of the methylation values for each individual using B-spline basis functions. The spline coefficients for each individual are allowed to summarize the individual's overall methylation profile. We then test for association between the overall distribution and a continuous or dichotomous outcome variable using a variance component score test that naturally accommodates the correlation between spline coefficients. Simulations indicate that our proposed approach has desirable power while protecting type I error. The method was applied to detect methylation differences, both genome wide and at LINE1 elements, between the blood samples from rheumatoid arthritis patients and healthy controls and to detect the epigenetic changes of human hepatocarcinogenesis in the context of alcohol abuse and hepatitis C virus infection. A free implementation of our methods in the R language is available in the Global Analysis of Methylation Profiles (GAMP) package at http://research.fhcrc.org/wu/en.html.
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Affiliation(s)
- Ni Zhao
- Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
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96
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Wip1 phosphatase in breast cancer. Oncogene 2014; 34:4429-38. [PMID: 25381821 DOI: 10.1038/onc.2014.375] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 10/02/2014] [Accepted: 10/05/2014] [Indexed: 12/13/2022]
Abstract
Understanding the factors contributing to tumor initiation, progression and evolution is of paramount significance. Among them, wild-type p53-induced phosphatase 1 (Wip1) is emerging as an important oncogene by virtue of its negative control on several key tumor suppressor pathways. Originally discovered as a p53-regulated gene, Wip1 has been subsequently found amplified and more recently mutated in a significant fraction of human cancers including breast tumors. Recent development in the field further uncovered the utility of anti-Wip1-directed therapies in delaying tumor onset or in reducing the tumor burden. Furthermore, Wip1 could be an important factor that contributes to tumor heterogeneity, suggesting that its inhibition may decrease the rate of cancer evolution. These effects depend on several signaling pathways modulated by Wip1 phosphatase in a spatial and temporal manner. In this review we discuss the recent development in understanding how Wip1 contributes to tumorigenesis with its relevance to breast cancer.
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97
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Mir AA, Philippe C, Cristofari G. euL1db: the European database of L1HS retrotransposon insertions in humans. Nucleic Acids Res 2014; 43:D43-7. [PMID: 25352549 PMCID: PMC4383891 DOI: 10.1093/nar/gku1043] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Retrotransposons account for almost half of our genome. They are mobile genetics elements—also known as jumping genes—but only the L1HS subfamily of Long Interspersed Nuclear Elements (LINEs) has retained the ability to jump autonomously in modern humans. Their mobilization in germline—but also some somatic tissues—contributes to human genetic diversity and to diseases, such as cancer. Here, we present euL1db, the European database of L1HS retrotransposon insertions in humans (available at http://euL1db.unice.fr). euL1db provides a curated and comprehensive summary of L1HS insertion polymorphisms identified in healthy or pathological human samples and published in peer-reviewed journals. A key feature of euL1db is its sample-wise organization. Hence L1HS insertion polymorphisms are connected to samples, individuals, families and clinical conditions. The current version of euL1db centralizes results obtained in 32 studies. It contains >900 samples, >140 000 sample-wise insertions and almost 9000 distinct merged insertions. euL1db will help understanding the link between L1 retrotransposon insertion polymorphisms and phenotype or disease.
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Affiliation(s)
- Ashfaq A Mir
- INSERM, U1081, Institute for Research on Cancer and Aging of Nice (IRCAN), F-06100 Nice, France CNRS, UMR 7284, Institute for Research on Cancer and Aging of Nice (IRCAN), F-06100 Nice, France Faculty of Medicine, Institute for Research on Cancer and Aging of Nice (IRCAN), University of Nice-Sophia-Antipolis, F-06100 Nice, France
| | - Claude Philippe
- INSERM, U1081, Institute for Research on Cancer and Aging of Nice (IRCAN), F-06100 Nice, France CNRS, UMR 7284, Institute for Research on Cancer and Aging of Nice (IRCAN), F-06100 Nice, France Faculty of Medicine, Institute for Research on Cancer and Aging of Nice (IRCAN), University of Nice-Sophia-Antipolis, F-06100 Nice, France
| | - Gaël Cristofari
- INSERM, U1081, Institute for Research on Cancer and Aging of Nice (IRCAN), F-06100 Nice, France CNRS, UMR 7284, Institute for Research on Cancer and Aging of Nice (IRCAN), F-06100 Nice, France Faculty of Medicine, Institute for Research on Cancer and Aging of Nice (IRCAN), University of Nice-Sophia-Antipolis, F-06100 Nice, France
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98
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Bakshi A, Kim J. Retrotransposon-based profiling of mammalian epigenomes: DNA methylation of IAP LTRs in embryonic stem, somatic and cancer cells. Genomics 2014; 104:538-44. [PMID: 25277721 DOI: 10.1016/j.ygeno.2014.09.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 09/19/2014] [Accepted: 09/21/2014] [Indexed: 11/24/2022]
Abstract
In the current study, we have used HT-TREBS to individually analyze the DNA methylation pattern of 4799 IAP LTR retrotransposons in embryonic stem, somatic and Neuro2A cells. According to the results, half of the loci within this family show constant methylation patterns between the three cell types whereas the remaining half display variable levels of methylation. About half of the variably methylated IAP LTRs tend to be hypomethylated in ES cells, and nearly all in this group are hypomethylated in Neuro2A cells. The observed hypomethylation in both cell types occur in a non-uniform, locus-specific manner and to various degrees of severity, with some of them being easily detectible by COBRA. Overall, this study demonstrates the feasibility of HT-TREBS to study DNA methylation changes at retrotransposons in a locus-specific manner in multiple cell types and further suggests the potential utility of this technique in developing epigenetic biomarkers for tracking disease progression.
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Affiliation(s)
- Arundhati Bakshi
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Joomyeong Kim
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
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99
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Inamura K, Yamauchi M, Nishihara R, Lochhead P, Qian ZR, Kuchiba A, Kim SA, Mima K, Sukawa Y, Jung S, Zhang X, Wu K, Cho E, Chan AT, Meyerhardt JA, Harris CC, Fuchs CS, Ogino S. Tumor LINE-1 methylation level and microsatellite instability in relation to colorectal cancer prognosis. J Natl Cancer Inst 2014; 106:dju195. [PMID: 25190725 DOI: 10.1093/jnci/dju195] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Hypomethylation in long interspersed nucleotide element-1 (LINE-1) and high-degree microsatellite instability (MSI-high) in colorectal cancer (CRC) have been associated with inferior and superior survival, respectively; however, it remains uncertain whether the prognostic association of LINE-1 hypomethylation differs by MSI status. We hypothesized that the adverse prognostic association of LINE-1 hypomethylation might be stronger in MSI-high CRCs than in microsatellite stable (MSS) CRCs. METHODS Utilizing 1211 CRCs in the Nurses' Health Study and the Health Professionals Follow-up Study, we examined patient survival according to LINE-1 hypomethylation status in strata of MSI status. A Cox proportional hazards model was used to compute multivariable CRC-specific mortality hazard ratios (HRs) for a 10% decrease in LINE-1 methylation level (range = 23.1-93.1%), adjusting for potential confounders, including CpG island methylator phenotype, and KRAS, BRAF, and PIK3CA mutations. Statistical tests (log-rank test, chi-square test, and likelihood ratio test) were two-sided. RESULTS In MSI-high cancers, the association of LINE-1 hypomethylation with higher mortality (HR = 2.45, 95% confidence interval [CI] = 1.64 to 3.66, P < .001) was stronger than that in MSS cancers (HR = 1.10, 95% CI = 0.98 to 1.24, P = .11) (P interaction < .001, between LINE-1 and MSI statuses). In MSI-high cases with CRC family history, the association of LINE-1 hypomethylation with higher mortality (HR = 5.13, 95% CI = 1.99 to 13.2; P < .001) was stronger than that in MSI-high cases without CRC family history (HR = 1.62, 95% CI = 0.89 to 2.94, P = .11) (P interaction = .02, between LINE-1 and CRC family history statuses). CONCLUSIONS The association of LINE-1 hypomethylation with inferior survival is stronger in MSI-high CRCs than in MSS CRCs. Tumor LINE-1 methylation level may be a useful prognostic biomarker to identify aggressive carcinomas among MSI-high CRCs.
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Affiliation(s)
- Kentaro Inamura
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Mai Yamauchi
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Reiko Nishihara
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Paul Lochhead
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Zhi Rong Qian
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Aya Kuchiba
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Sun A Kim
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Kosuke Mima
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Yasutaka Sukawa
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Seungyoun Jung
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Xuehong Zhang
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Kana Wu
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Eunyoung Cho
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Andrew T Chan
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Jeffrey A Meyerhardt
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Curtis C Harris
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Charles S Fuchs
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
| | - Shuji Ogino
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA (KI, MY, RN, PL, ZRQ, AK, SAK, KM, YS, JAM, CSF, SO); Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD (KI, CCH); Department of Nutrition, Harvard School of Public Health, Boston, MA (RN, AK, KW); Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK (PL); Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SJ, XZ, EC, ATC, CSF); Department of Dermatology, The Warren Alpert Medical School of Brown University, Province, RI (EC); Division of Gastroenterology, Massachusetts General Hospital, Boston, MA (ATC); Department of Epidemiology, Harvard School of Public Health, Boston, MA (SO); Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA (SO)
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LINE-1 retrotransposons: from 'parasite' sequences to functional elements. J Appl Genet 2014; 56:133-45. [PMID: 25106509 DOI: 10.1007/s13353-014-0241-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 07/24/2014] [Accepted: 07/25/2014] [Indexed: 10/24/2022]
Abstract
Long interspersed nuclear elements-1 (LINE-1) are the most abundant and active retrotransposons in the mammalian genomes. Traditionally, the occurrence of LINE-1 sequences in the genome of mammals has been explained by the selfish DNA hypothesis. Nevertheless, recently, it has also been argued that these sequences could play important roles in these genomes, as in the regulation of gene expression, genome modelling and X-chromosome inactivation. The non-random chromosomal distribution is a striking feature of these retroelements that somehow reflects its functionality. In the present study, we have isolated and analysed a fraction of the open reading frame 2 (ORF2) LINE-1 sequence from three rodent species, Cricetus cricetus, Peromyscus eremicus and Praomys tullbergi. Physical mapping of the isolated sequences revealed an interspersed longitudinal AT pattern of distribution along all the chromosomes of the complement in the three genomes. A detailed analysis shows that these sequences are preferentially located in the euchromatic regions, although some signals could be detected in the heterochromatin. In addition, a coincidence between the location of imprinted gene regions (as Xist and Tsix gene regions) and the LINE-1 retroelements was also observed. According to these results, we propose an involvement of LINE-1 sequences in different genomic events as gene imprinting, X-chromosome inactivation and evolution of repetitive sequences located at the heterochromatic regions (e.g. satellite DNA sequences) of the rodents' genomes analysed.
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