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Ross JP, van Dijk S, Phang M, Skilton MR, Molloy PL, Oytam Y. Batch-effect detection, correction and characterisation in Illumina HumanMethylation450 and MethylationEPIC BeadChip array data. Clin Epigenetics 2022; 14:58. [PMID: 35488315 PMCID: PMC9055778 DOI: 10.1186/s13148-022-01277-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/10/2022] [Indexed: 11/20/2022] Open
Abstract
Background Genomic technologies can be subject to significant batch-effects which are known to reduce experimental power and to potentially create false positive results. The Illumina Infinium Methylation BeadChip is a popular technology choice for epigenome-wide association studies (EWAS), but presently, little is known about the nature of batch-effects on these designs. Given the subtlety of biological phenotypes in many EWAS, control for batch-effects should be a consideration.
Results Using the batch-effect removal approaches in the ComBat and Harman software, we examined two in-house datasets and compared results with three large publicly available datasets, (1214 HumanMethylation450 and 1094 MethylationEPIC BeadChips in total), and find that despite various forms of preprocessing, some batch-effects persist. This residual batch-effect is associated with the day of processing, the individual glass slide and the position of the array on the slide. Consistently across all datasets, 4649 probes required high amounts of correction. To understand the impact of this set to EWAS studies, we explored the literature and found three instances where persistently batch-effect prone probes have been reported in abstracts as key sites of differential methylation. As well as batch-effect susceptible probes, we also discover a set of probes which are erroneously corrected. We provide batch-effect workflows for Infinium Methylation data and provide reference matrices of batch-effect prone and erroneously corrected features across the five datasets spanning regionally diverse populations and three commonly collected biosamples (blood, buccal and saliva). Conclusions Batch-effects are ever present, even in high-quality data, and a strategy to deal with them should be part of experimental design, particularly for EWAS. Batch-effect removal tools are useful to reduce technical variance in Infinium Methylation data, but they need to be applied with care and make use of post hoc diagnostic measures. Supplementary Information The online version contains supplementary material available at 10.1186/s13148-022-01277-9.
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Affiliation(s)
- Jason P Ross
- Human Health Program, Health and Biosecurity, CSIRO, Sydney, Australia.
| | - Susan van Dijk
- Human Health Program, Health and Biosecurity, CSIRO, Sydney, Australia
| | - Melinda Phang
- Charles Perkins Centre, The University of Sydney, Sydney, Australia
| | - Michael R Skilton
- Charles Perkins Centre, The University of Sydney, Sydney, Australia.,Sydney Medical School, The University of Sydney, Sydney, Australia.,Sydney Institute for Women, Children and Their Families, Sydney Local Health District, Sydney, Australia
| | - Peter L Molloy
- Human Health Program, Health and Biosecurity, CSIRO, Sydney, Australia
| | - Yalchin Oytam
- Clinical Insights and Analytics Unit, South Eastern Sydney Local Health District, Sydney, Australia
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Clark SJ, Molloy PL. Early Insights into Cancer Epigenetics: Gene Promoter Hypermethylation Emerges as a Potential Biomarker for Cancer Detection. Cancer Res 2022; 82:1461-1463. [DOI: 10.1158/0008-5472.can-22-0657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/01/2022] [Indexed: 11/16/2022]
Abstract
Abstract
DNA methylation is one of the most intensely studied epigenetic modifications in mammals. In normal cells, it plays an essential role in core biologic processes by assuring the proper regulation of gene expression and stable gene silencing. In cancer cells, genome-wide DNA methylation patterns are altered and often represent an early and fundamental step in neoplastic transformation. The landmark study from Esteller and colleagues, published in Cancer Research in 2001, was the first to reveal high frequency promoter methylation across multiple cancer types. They highlighted that widespread alterations in DNA methylation may be a key characteristic of oncogenesis and proposed aberrant DNA methylation of gene promoters could provide markers for sensitive detection of nearly all cancer types. The authors used a candidate gene approach to show promoter hypermethylation occurred across 12 cancer-associated genes in DNA from over 600 primary tumor samples, representing 15 major tumor types. The profile of promoter hypermethylation differed in every tumor type, suggesting that alterations in DNA methylation are pervasive, but the genes affected may be tumor-specific and impact multiple signaling pathways. Over the past 20 years since this publication, the cancer epigenetics field has exploded to generate thousands of normal and cancer methylome maps and developed sophisticated informatic tools for genome-wide methylome analyses. These methylomes are providing roadmaps for the study of cancer biology and discovery of DNA methylation biomarkers for early detection and monitoring of cancer.
See related article by Esteller and colleagues, Cancer Res 2001;61:3225–29.
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Affiliation(s)
- Susan J. Clark
- Epigenetics Research Laboratory, Genomics and Epigenetics Theme, The Garvan Institute of Medical Research, Sydney, New South Wales, Australia
- St Vincent's Clinical School, UNSW Sydney, New South Wales, Australia
| | - Peter L. Molloy
- CSIRO Health and Biosecurity, Sydney, New South Wales, Australia
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3
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Vehmeijer FOL, Küpers LK, Sharp GC, Salas LA, Lent S, Jima DD, Tindula G, Reese S, Qi C, Gruzieva O, Page C, Rezwan FI, Melton PE, Nohr E, Escaramís G, Rzehak P, Heiskala A, Gong T, Tuominen ST, Gao L, Ross JP, Starling AP, Holloway JW, Yousefi P, Aasvang GM, Beilin LJ, Bergström A, Binder E, Chatzi L, Corpeleijn E, Czamara D, Eskenazi B, Ewart S, Ferre N, Grote V, Gruszfeld D, Håberg SE, Hoyo C, Huen K, Karlsson R, Kull I, Langhendries JP, Lepeule J, Magnus MC, Maguire RL, Molloy PL, Monnereau C, Mori TA, Oken E, Räikkönen K, Rifas-Shiman S, Ruiz-Arenas C, Sebert S, Ullemar V, Verduci E, Vonk JM, Xu CJ, Yang IV, Zhang H, Zhang W, Karmaus W, Dabelea D, Muhlhausler BS, Breton CV, Lahti J, Almqvist C, Jarvelin MR, Koletzko B, Vrijheid M, Sørensen TIA, Huang RC, Arshad SH, Nystad W, Melén E, Koppelman GH, London SJ, Holland N, Bustamante M, Murphy SK, Hivert MF, Baccarelli A, Relton CL, Snieder H, Jaddoe VWV, Felix JF. DNA methylation and body mass index from birth to adolescence: meta-analyses of epigenome-wide association studies. Genome Med 2020; 12:105. [PMID: 33239103 PMCID: PMC7687793 DOI: 10.1186/s13073-020-00810-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 11/12/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND DNA methylation has been shown to be associated with adiposity in adulthood. However, whether similar DNA methylation patterns are associated with childhood and adolescent body mass index (BMI) is largely unknown. More insight into this relationship at younger ages may have implications for future prevention of obesity and its related traits. METHODS We examined whether DNA methylation in cord blood and whole blood in childhood and adolescence was associated with BMI in the age range from 2 to 18 years using both cross-sectional and longitudinal models. We performed meta-analyses of epigenome-wide association studies including up to 4133 children from 23 studies. We examined the overlap of findings reported in previous studies in children and adults with those in our analyses and calculated enrichment. RESULTS DNA methylation at three CpGs (cg05937453, cg25212453, and cg10040131), each in a different age range, was associated with BMI at Bonferroni significance, P < 1.06 × 10-7, with a 0.96 standard deviation score (SDS) (standard error (SE) 0.17), 0.32 SDS (SE 0.06), and 0.32 BMI SDS (SE 0.06) higher BMI per 10% increase in methylation, respectively. DNA methylation at nine additional CpGs in the cross-sectional childhood model was associated with BMI at false discovery rate significance. The strength of the associations of DNA methylation at the 187 CpGs previously identified to be associated with adult BMI, increased with advancing age across childhood and adolescence in our analyses. In addition, correlation coefficients between effect estimates for those CpGs in adults and in children and adolescents also increased. Among the top findings for each age range, we observed increasing enrichment for the CpGs that were previously identified in adults (birth Penrichment = 1; childhood Penrichment = 2.00 × 10-4; adolescence Penrichment = 2.10 × 10-7). CONCLUSIONS There were only minimal associations of DNA methylation with childhood and adolescent BMI. With the advancing age of the participants across childhood and adolescence, we observed increasing overlap with altered DNA methylation loci reported in association with adult BMI. These findings may be compatible with the hypothesis that DNA methylation differences are mostly a consequence rather than a cause of obesity.
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Affiliation(s)
- Florianne O L Vehmeijer
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, Room Na-2918, Erasmus MC, PO Box 2040, 3000 CA, Rotterdam, the Netherlands
- Department of Pediatrics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Leanne K Küpers
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- University of Groningen, University Medical Center Groningen, Department of Epidemiology, Groningen, the Netherlands
| | - Gemma C Sharp
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
| | - Lucas A Salas
- Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
- ISGlobal, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER of Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - Samantha Lent
- Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA
| | - Dereje D Jima
- Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA
| | - Gwen Tindula
- Children's Environmental Health Laboratory, Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA
| | - Sarah Reese
- Department of Health and Human Services, Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Cancan Qi
- University of Groningen, University Medical Center Groningen, Department of Pediatric Pulmonology and Pediatric Allergy, Beatrix Children's Hospital, Groningen, The Netherlands
- University Medical Center Groningen GRIAC Research Institute, University of Groningen, Groningen, the Netherlands
| | - Olena Gruzieva
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
- Centre for Occupational and Environmental Medicine, Region Stockholm, Stockholm, Sweden
| | - Christian Page
- Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway
- Oslo Centre for Biostatistics and Epidemiology, Oslo University Hospital, Oslo, Norway
| | - Faisal I Rezwan
- School of Water, Energy and Environment, Cranfield University, Cranfield, Bedfordshire, UK
- Human Development and Health, Faculty of Medicine, Southampton General Hospital, University of Southampton, Southampton, UK
| | - Philip E Melton
- School of Pharmacy and Biomedical Sciences, Curtin University, Bentley, Western Australia, Australia
- School of Biomedical Sciences, The University of Western Australia, Crawley, Western Austalia, Australia
| | - Ellen Nohr
- Centre for Women's, Family and Child Health, University of South-Eastern Norway, Kongsberg, Norway
- Institute of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Geòrgia Escaramís
- CIBER of Epidemiology and Public Health (CIBERESP), Madrid, Spain
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
- Research group on Statistics, Econometrics and Health (GRECS), University of Girona, Girona, Spain
| | - Peter Rzehak
- Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, Ludwig-Maximilians Universität München (LMU), Munich, Germany
| | - Anni Heiskala
- Center for Life Course Health Research, University of Oulu, Oulu, Finland
| | - Tong Gong
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Samuli T Tuominen
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Lu Gao
- Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA
| | - Jason P Ross
- CSIRO Health and Biosecurity, North Ryde, New South Wales, Australia
| | - Anne P Starling
- Department of Epidemiology, Colorado School of Public Health, Aurora, CO, USA
- Lifecourse Epidemiology of Adiposity and Diabetes (LEAD) Center, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - John W Holloway
- Human Development and Health, Faculty of Medicine, Southampton General Hospital, University of Southampton, Southampton, UK
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Paul Yousefi
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
| | - Gunn Marit Aasvang
- Department of Air Pollution and Noise, Norwegian Institute of Public Health, Oslo, Norway
| | | | - Anna Bergström
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
- Centre for Occupational and Environmental Medicine, Region Stockholm, Stockholm, Sweden
| | - Elisabeth Binder
- Department of Translational Research in Psychiatry, Max-Planck-Institute of Psychiatry, Munich, Germany
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA
| | - Leda Chatzi
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Eva Corpeleijn
- University of Groningen, University Medical Center Groningen, Department of Epidemiology, Groningen, the Netherlands
| | - Darina Czamara
- Department of Translational Research in Psychiatry, Max-Planck-Institute of Psychiatry, Munich, Germany
| | - Brenda Eskenazi
- Center for Environmental Research and Children's Health, School of Public Health, University of California, Berkeley, CA, USA
| | - Susan Ewart
- College of Veterinary Medicine, Michigan State University, East Lansing, MI, USA
| | - Natalia Ferre
- Pediatrics, Nutrition and Development Research Unit, Universitat Rovira i Virgili, IISPV, Reus, Spain
| | - Veit Grote
- Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, Ludwig-Maximilians Universität München (LMU), Munich, Germany
| | - Dariusz Gruszfeld
- Neonatal Department, Children's Memorial Health Institute, Warsaw, Poland
| | - Siri E Håberg
- Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Cathrine Hoyo
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Karen Huen
- Children's Environmental Health Laboratory, Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA
| | - Robert Karlsson
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Inger Kull
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
- Sachs' Children and Youth Hospital, Södersjukhuset, Stockholm, Sweden
| | | | - Johanna Lepeule
- Université Grenoble Alpes, Inserm, CNRS, Team of Environmental Epidemiology Applied to Reproduction and Respiratory Health, IAB, Grenoble, France
| | - Maria C Magnus
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Rachel L Maguire
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
- Department of Obstetrics and Gynecology, Duke University Medical Center, Raleigh, NC, USA
| | - Peter L Molloy
- CSIRO Health and Biosecurity, North Ryde, New South Wales, Australia
| | - Claire Monnereau
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, Room Na-2918, Erasmus MC, PO Box 2040, 3000 CA, Rotterdam, the Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Trevor A Mori
- Medical School, University of Western Australia, Perth, Australia
| | - Emily Oken
- Department of Population Medicine, Harvard Medical School, Harvard Pilgrim Health Care Institute, Boston, MA, USA
| | - Katri Räikkönen
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Sheryl Rifas-Shiman
- Department of Population Medicine, Harvard Medical School, Harvard Pilgrim Health Care Institute, Boston, MA, USA
| | - Carlos Ruiz-Arenas
- ISGlobal, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER of Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - Sylvain Sebert
- Center for Life Course Health Research, University of Oulu, Oulu, Finland
| | - Vilhelmina Ullemar
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Elvira Verduci
- Department of Pediatrics, San Paolo Hospital, University of Milan, Milan, Italy
| | - Judith M Vonk
- University of Groningen, University Medical Center Groningen, Department of Epidemiology, Groningen, the Netherlands
- University Medical Center Groningen GRIAC Research Institute, University of Groningen, Groningen, the Netherlands
| | - Cheng-Jian Xu
- University of Groningen, University Medical Center Groningen, Department of Pediatric Pulmonology and Pediatric Allergy, Beatrix Children's Hospital, Groningen, The Netherlands
- University Medical Center Groningen GRIAC Research Institute, University of Groningen, Groningen, the Netherlands
- Department of Gastroenterology, Hepatology and Endocrinology, CiiM, Centre for Individualised Infection Medicine, a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
- TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
| | - Ivana V Yang
- Department of Epidemiology, Colorado School of Public Health, Aurora, CO, USA
- Division of Biomedical Informatics and Personalized Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
- Center for Genes, Environment and Health, National Jewish Health, Denver, CO, USA
| | - Hongmei Zhang
- Division of Epidemiology, Biostatistics, and Environmental Health, University of Memphis, Memphis, TN, USA
| | - Weiming Zhang
- Department of Biostatistics and Informatics, Colorado School of Public Health, Aurora, CO, USA
| | - Wilfried Karmaus
- Division of Epidemiology, Biostatistics, and Environmental Health, University of Memphis, Memphis, TN, USA
| | - Dana Dabelea
- Department of Epidemiology, Colorado School of Public Health, Aurora, CO, USA
- Lifecourse Epidemiology of Adiposity and Diabetes (LEAD) Center, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Department of Pediatrics, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | | | - Carrie V Breton
- Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA
| | - Jari Lahti
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Turku Institute for Advanced Studies, University of Turku, Turku, Finland
| | - Catarina Almqvist
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
- Pediatric Allergy and Pulmonology Unit at Astrid Lindgren Children's Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Marjo-Riitta Jarvelin
- Center for Life Course Health Research, University of Oulu, Oulu, Finland
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
- Unit of Primary Health Care, Oulu University Hospital, OYS, Oulu, Finland
- Department of Life Sciences, College of Health and Life Sciences, Brunel University London, London, UK
| | - Berthold Koletzko
- Division of Metabolic and Nutritional Medicine, Dr. von Hauner Children's Hospital, Ludwig-Maximilians Universität München (LMU), Munich, Germany
| | - Martine Vrijheid
- ISGlobal, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER of Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - Thorkild I A Sørensen
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Department of Public Health, Section of Epidemiology, and The Novo Nordisk Foundation Center for Basic Metabolic Research, Section on Metabolic Genetics, Faculty of Medical and Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rae-Chi Huang
- Telethon Kids Institute, University of Western Australia, Perth, Australia
| | - Syed Hasan Arshad
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- David Hide Asthma and Allergy Research Centre, Isle of Wight, UK
| | - Wenche Nystad
- Department of Chronic Diseases and Ageing, Norwegian Institute of Public Health, Oslo, Norway
| | - Erik Melén
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
- Sachs' Children and Youth Hospital, Södersjukhuset, Stockholm, Sweden
| | - Gerard H Koppelman
- University of Groningen, University Medical Center Groningen, Department of Pediatric Pulmonology and Pediatric Allergy, Beatrix Children's Hospital, Groningen, The Netherlands
- University Medical Center Groningen GRIAC Research Institute, University of Groningen, Groningen, the Netherlands
| | - Stephanie J London
- Department of Health and Human Services, Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Nina Holland
- Children's Environmental Health Laboratory, Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, USA
| | - Mariona Bustamante
- ISGlobal, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER of Epidemiology and Public Health (CIBERESP), Madrid, Spain
| | - Susan K Murphy
- Department of Obstetrics and Gynecology, Duke University Medical Center, Raleigh, NC, USA
| | - Marie-France Hivert
- Department of Population Medicine, Harvard Medical School, Harvard Pilgrim Health Care Institute, Boston, MA, USA
- Diabetes Unit, Massachusetts General Hospital, Boston, MA, USA
- Department of Medicine, Universite de Sherbrooke, Sherbrooke, QC, Canada
| | - Andrea Baccarelli
- Department of Environmental Health Sciences, Columbia University Mailman School of Public Health, New York, NY, USA
| | - Caroline L Relton
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
| | - Harold Snieder
- University of Groningen, University Medical Center Groningen, Department of Epidemiology, Groningen, the Netherlands
| | - Vincent W V Jaddoe
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, Room Na-2918, Erasmus MC, PO Box 2040, 3000 CA, Rotterdam, the Netherlands
- Department of Pediatrics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Janine F Felix
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, Room Na-2918, Erasmus MC, PO Box 2040, 3000 CA, Rotterdam, the Netherlands.
- Department of Pediatrics, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands.
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Mitchell SM, Rand KN, Xu ZZ, Ho T, Brown GS, Ross JP, Molloy PL. Helper-Dependent Chain Reaction (HDCR) for Selective Amplification of Methylated DNA Sequences. Methods Mol Biol 2018; 1708:587-601. [PMID: 29224165 DOI: 10.1007/978-1-4939-7481-8_30] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Over the last few years a number of restriction enzymes that cut DNA only if cytosines within their recognition sequences are methylated have been characterized and become commercially available. Cleavage with these enzymes to release DNA fragments in a methylation-dependent manner can be combined with a novel method of amplification, Helper Dependent Chain Reaction (HDCR), to selectively amplify these fragments. HDCR uses "Helper" oligonucleotides as templates for extension of the free 3' end of target fragments to incorporate tag sequences at the ends of fragments. These tag sequences are then used for priming of amplification of target fragments. Modifications to the amplification primers (Drivers) and the Helpers ensure that there is selection for the sequences within target fragments with each cycle of amplification. The combination of methylation-dependent enzymes and HDCR allows the sensitive and selective amplification of methylated DNA sequences without the need for bisulfite treatment.
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Affiliation(s)
- Susan M Mitchell
- CSIRO Food and Nutrition Flagship, PO Box 52, North Ryde, NSW, 1670, Australia
| | - Keith N Rand
- CSIRO Food and Nutrition Flagship, PO Box 52, North Ryde, NSW, 1670, Australia
| | - Zheng-Zhou Xu
- CSIRO Food and Nutrition Flagship, PO Box 52, North Ryde, NSW, 1670, Australia
| | - Thu Ho
- CSIRO Food and Nutrition Flagship, PO Box 52, North Ryde, NSW, 1670, Australia
| | - Glenn S Brown
- CSIRO Food and Nutrition Flagship, PO Box 52, North Ryde, NSW, 1670, Australia
| | - Jason P Ross
- CSIRO Food and Nutrition Flagship, PO Box 52, North Ryde, NSW, 1670, Australia
| | - Peter L Molloy
- CSIRO Food and Nutrition Flagship, PO Box 52, North Ryde, NSW, 1670, Australia.
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5
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Suraweera N, Mouradov D, Li S, Jorissen RN, Hampson D, Ghosh A, Sengupta N, Thaha M, Ahmed S, Kirwan M, Aleva F, Propper D, Feakins RM, Vulliamy T, Elwood NJ, Tian P, Ward RL, Hawkins NJ, Xu ZZ, Molloy PL, Jones IT, Croxford M, Gibbs P, Silver A, Sieber OM. Relative telomere lengths in tumor and normal mucosa are related to disease progression and chromosome instability profiles in colorectal cancer. Oncotarget 2017; 7:36474-36488. [PMID: 27167335 PMCID: PMC5095014 DOI: 10.18632/oncotarget.9015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/10/2016] [Indexed: 01/02/2023] Open
Abstract
Telomeric dysfunction is linked to colorectal cancer (CRC) initiation. However, the relationship of normal tissue and tumor telomere lengths with CRC progression, molecular features and prognosis is unclear. Here, we measured relative telomere length (RTL) by real-time quantitative PCR in 90 adenomas (aRTL), 419 stage I-IV CRCs (cRTL) and adjacent normal mucosa (nRTL). Age-adjusted RTL was analyzed against germline variants in telomere biology genes, chromosome instability (CIN), microsatellite instability (MSI), CpG island methylator phenotype (CIMP), TP53, KRAS, BRAF mutations and clinical outcomes. In 509 adenoma or CRC patients, nRTL decreased with advancing age. Female gender, proximal location and the TERT rs2736100 G allele were independently associated with longer age-adjusted nRTL. Adenomas and carcinomas exhibited telomere shortening in 79% and 67% and lengthening in 7% and 15% of cases. Age-adjusted nRTL and cRTL were independently associated with tumor stage, decreasing from adenoma to stage III and leveling out or increasing from stage III to IV, respectively. Cancer MSI, CIMP, TP53, KRAS and BRAF status were not related to nRTL or cRTL. Near-tetraploid CRCs exhibited significantly longer cRTLs than CIN- and aneuploidy CRCs, while cRTL was significantly shorter in CRCs with larger numbers of chromosome breaks. Age-adjusted nRTL, cRTL or cRTL:nRTL ratios were not associated with disease-free or overall survival in stage II/III CRC. Taken together, our data show that both normal mucosa and tumor RTL are independently associated with CRC progression, and highlight divergent associations of CRC telomere length with tumor CIN profiles.
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Affiliation(s)
- Nirosha Suraweera
- Centre for Digestive Diseases, Blizard Institute, Barts and The London School of Medicine and Dentistry, Whitechapel, London, UK
| | - Dmitri Mouradov
- Systems Biology and Personalised Medicine Division, The Walter and Eliza Hall Institute of Medial Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Shan Li
- Systems Biology and Personalised Medicine Division, The Walter and Eliza Hall Institute of Medial Research, Parkville, Victoria, Australia
| | - Robert N Jorissen
- Systems Biology and Personalised Medicine Division, The Walter and Eliza Hall Institute of Medial Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia
| | - Debbie Hampson
- Centre for Digestive Diseases, Blizard Institute, Barts and The London School of Medicine and Dentistry, Whitechapel, London, UK
| | - Anil Ghosh
- Centre for Digestive Diseases, Blizard Institute, Barts and The London School of Medicine and Dentistry, Whitechapel, London, UK
| | - Neel Sengupta
- Centre for Digestive Diseases, Blizard Institute, Barts and The London School of Medicine and Dentistry, Whitechapel, London, UK
| | - Mohamed Thaha
- Centre for Digestive Diseases, Blizard Institute, Barts and The London School of Medicine and Dentistry, Whitechapel, London, UK.,Academic Surgical Unit, The Royal London Hospital, Whitechapel, London, UK
| | - Shafi Ahmed
- Academic Surgical Unit, The Royal London Hospital, Whitechapel, London, UK
| | - Michael Kirwan
- Centre for Paediatrics, Blizard Institute, Barts and The London School of Medicine and Dentistry, Whitechapel, London, UK
| | - Floor Aleva
- Department of Medical Oncology, St Bartholomew's Hospital, Little Britain, London, UK
| | - David Propper
- Department of Medical Oncology, St Bartholomew's Hospital, Little Britain, London, UK
| | - Roger M Feakins
- Department of Pathology, The Royal London Hospital, Whitechapel, London, UK
| | - Tom Vulliamy
- Centre for Genomics and Child Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, Whitechapel, London, UK
| | - Ngaire J Elwood
- Cord Blood Research, Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Pei Tian
- Cord Blood Research, Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Robyn L Ward
- The University of Queensland, Brisbane, Queensland, Australia
| | - Nicholas J Hawkins
- School of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Zheng-Zhou Xu
- CSIRO Preventative Health Flagship, North Ryde, NSW, Australia
| | - Peter L Molloy
- CSIRO Preventative Health Flagship, North Ryde, NSW, Australia
| | - Ian T Jones
- Department of Colorectal Surgery, Royal Melbourne Hospital, Parkville, Victoria, Australia.,Department of Surgery, The University of Melbourne, Parkville, Victoria, Australia
| | - Matthew Croxford
- Department of Colorectal Surgery, Western Hospital, Footscray, Victoria, Australia
| | - Peter Gibbs
- Systems Biology and Personalised Medicine Division, The Walter and Eliza Hall Institute of Medial Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia.,Department of Medical Oncology, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Andrew Silver
- Centre for Digestive Diseases, Blizard Institute, Barts and The London School of Medicine and Dentistry, Whitechapel, London, UK
| | - Oliver M Sieber
- Systems Biology and Personalised Medicine Division, The Walter and Eliza Hall Institute of Medial Research, Parkville, Victoria, Australia.,Department of Medical Biology, The University of Melbourne, Parkville, Victoria, Australia.,Department of Surgery, The University of Melbourne, Parkville, Victoria, Australia.,School of Biomedical Sciences, Monash University, Victoria, Australia
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6
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Abstract
How genetic and epigenetic events synergize to generate the oncogenic state is not well understood. In this issue of Cancer Cell, Vaz et al. provide compelling evidence that exposure to chronic cigarette smoke causes progressive epigenetic alterations that prime for key genetic events to drive the development of lung cancer.
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Affiliation(s)
- Susan J Clark
- Epigenetics Research Laboratory, Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia; St. Vincent's Clinical School, UNSW Sydney, Sydney, NSW 1466, Australia.
| | - Peter L Molloy
- CSIRO Health and Biosecurity, PO Box 52, North Ryde, NSW 1670, Australia
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7
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Mitchell SM, Ho T, Brown GS, Baker RT, Thomas ML, McEvoy A, Xu ZZ, Ross JP, Lockett TJ, Young GP, LaPointe LC, Pedersen SK, Molloy PL. Evaluation of Methylation Biomarkers for Detection of Circulating Tumor DNA and Application to Colorectal Cancer. Genes (Basel) 2016; 7:E125. [PMID: 27983717 PMCID: PMC5192501 DOI: 10.3390/genes7120125] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 11/03/2016] [Accepted: 11/29/2016] [Indexed: 12/29/2022] Open
Abstract
Solid tumors shed DNA into circulation, and there is growing evidence that the detection of circulating tumor DNA (ctDNA) has broad clinical utility, including monitoring of disease, prognosis, response to chemotherapy and tracking tumor heterogeneity. The appearance of ctDNA in the circulating cell-free DNA (ccfDNA) isolated from plasma or serum is commonly detected by identifying tumor-specific features such as insertions, deletions, mutations and/or aberrant methylation. Methylation is a normal cell regulatory event, and since the majority of ccfDNA is derived from white blood cells (WBC), it is important that tumour-specific DNA methylation markers show rare to no methylation events in WBC DNA. We have used a novel approach for assessment of low levels of DNA methylation in WBC DNA. DNA methylation in 29 previously identified regions (residing in 17 genes) was analyzed in WBC DNA and eight differentially-methylated regions (DMRs) were taken through to testing in clinical samples using methylation specific PCR assays. DMRs residing in four genes, BCAT1, GRASP, IKZF1 and IRF4, exhibited low positivity, 3.5% to 7%, in the plasma of colonoscopy-confirmed healthy subjects, with the sensitivity for detection of ctDNA in colonoscopy-confirmed patients with colorectal cancer being 65%, 54.5%, 67.6% and 59% respectively.
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Affiliation(s)
- Susan M Mitchell
- CSIRO Food and Nutrition, P.O. Box 52, North Ryde, NSW 1670, Australia.
| | - Thu Ho
- CSIRO Food and Nutrition, P.O. Box 52, North Ryde, NSW 1670, Australia.
| | - Glenn S Brown
- CSIRO Food and Nutrition, P.O. Box 52, North Ryde, NSW 1670, Australia.
| | - Rohan T Baker
- Clinical Genomics Pty Ltd., North Ryde, NSW 2113, Australia.
| | | | - Aidan McEvoy
- Clinical Genomics Pty Ltd., North Ryde, NSW 2113, Australia.
| | - Zheng-Zhou Xu
- CSIRO Food and Nutrition, P.O. Box 52, North Ryde, NSW 1670, Australia.
| | - Jason P Ross
- CSIRO Food and Nutrition, P.O. Box 52, North Ryde, NSW 1670, Australia.
| | - Trevor J Lockett
- CSIRO Food and Nutrition, P.O. Box 52, North Ryde, NSW 1670, Australia.
| | - Graeme P Young
- Flinders Centre for Innovation in Cancer, Flinders University of South Australia, GPO Box 2100, Adelaide, SA 5001, Australia.
| | | | | | - Peter L Molloy
- CSIRO Food and Nutrition, P.O. Box 52, North Ryde, NSW 1670, Australia.
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8
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Barras D, Missiaglia E, Wirapati P, Sieber OM, Jorissen RN, Love C, Molloy PL, Jones IT, McLaughlin S, Gibbs P, Guinney J, Simon IM, Roth AD, Bosman FT, Tejpar S, Delorenzi M. BRAFV600E Mutant Colorectal Cancer Subtypes Based on Gene Expression. Clin Cancer Res 2016; 23:104-115. [DOI: 10.1158/1078-0432.ccr-16-0140] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 05/20/2016] [Accepted: 06/09/2016] [Indexed: 12/18/2022]
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9
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Varinli H, Statham AL, Clark SJ, Molloy PL, Ross JP. COBRA-Seq: Sensitive and Quantitative Methylome Profiling. Genes (Basel) 2015; 6:1140-63. [PMID: 26512698 PMCID: PMC4690032 DOI: 10.3390/genes6041140] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 09/22/2015] [Accepted: 09/24/2015] [Indexed: 12/15/2022] Open
Abstract
Combined Bisulfite Restriction Analysis (COBRA) quantifies DNA methylation at a specific locus. It does so via digestion of PCR amplicons produced from bisulfite-treated DNA, using a restriction enzyme that contains a cytosine within its recognition sequence, such as TaqI. Here, we introduce COBRA-seq, a genome wide reduced methylome method that requires minimal DNA input (0.1-1.0 mg) and can either use PCR or linear amplification to amplify the sequencing library. Variants of COBRA-seq can be used to explore CpG-depleted as well as CpG-rich regions in vertebrate DNA. The choice of enzyme influences enrichment for specific genomic features, such as CpG-rich promoters and CpG islands, or enrichment for less CpG dense regions such as enhancers. COBRA-seq coupled with linear amplification has the additional advantage of reduced PCR bias by producing full length fragments at high abundance. Unlike other reduced representative methylome methods, COBRA-seq has great flexibility in the choice of enzyme and can be multiplexed and tuned, to reduce sequencing costs and to interrogate different numbers of sites. Moreover, COBRA-seq is applicable to non-model organisms without the reference genome and compatible with the investigation of non-CpG methylation by using restriction enzymes containing CpA, CpT, and CpC in their recognition site.
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Affiliation(s)
- Hilal Varinli
- CSIRO Food and Nutrition Flagship, North Ryde, New South Wales 1670, Australia.
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia.
- Department of Biological Sciences, Macquarie University, North Ryde, New South Wales 2109, Australia.
| | - Aaron L Statham
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia.
| | - Susan J Clark
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia.
- Vincent's Clinical School, Faculty of Medicine, UNSW, New South Wales 2010, Australia.
| | - Peter L Molloy
- CSIRO Food and Nutrition Flagship, North Ryde, New South Wales 1670, Australia.
| | - Jason P Ross
- CSIRO Food and Nutrition Flagship, North Ryde, New South Wales 1670, Australia.
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10
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Varinli H, Osmond-McLeod MJ, Molloy PL, Vallotton P. LipiD-QuanT: a novel method to quantify lipid accumulation in live cells. J Lipid Res 2015; 56:2206-16. [PMID: 26330056 DOI: 10.1194/jlr.d059758] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Indexed: 12/17/2022] Open
Abstract
Lipid droplets (LDs) are the main storage organelles for triglycerides. Elucidation of lipid accumulation mechanisms and metabolism are essential to understand obesity and associated diseases. Adipogenesis has been well studied in murine 3T3-L1 and human Simpson-Golabi-Behmel syndrome (SGBS) preadipocyte cell lines. However, most techniques for measuring LD accumulation are either not quantitative or can be destructive to samples. Here, we describe a novel, label-free LD quantification technique (LipiD-QuanT) to monitor lipid dynamics based on automated image analysis of phase contrast microscopy images acquired during in vitro human adipogenesis. We have applied LipiD-QuanT to measure LD accumulation during differentiation of SGBS cells. We demonstrate that LipiD-QuanT is a robust, nondestructive, time- and cost-effective method compared with other triglyceride accumulation assays based on enzymatic digest or lipophilic staining. Further, we applied LipiD-QuanT to measure the effect of four potential pro- or antiobesogenic substances: DHA, rosiglitazone, elevated levels of D-glucose, and zinc oxide nanoparticles. Our results revealed that 2 µmol/l rosiglitazone treatment during adipogenesis reduced lipid production and caused a negative shift in LD diameter size distribution, but the other treatments showed no effect under the conditions used here.
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Affiliation(s)
- Hilal Varinli
- CSIRO Food and Nutrition Flagship, North Ryde, New South Wales, Australia Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia Genomics and Epigenetics Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Megan J Osmond-McLeod
- CSIRO Food and Nutrition Flagship, North Ryde, New South Wales, Australia CSIRO Advanced Materials TCP (Nanosafety), North Ryde, New South Wales, Australia
| | - Peter L Molloy
- CSIRO Food and Nutrition Flagship, North Ryde, New South Wales, Australia
| | - Pascal Vallotton
- CSIRO Digital Productivity Flagship, North Ryde, New South Wales, Australia
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11
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van Dijk SJ, Tellam RL, Morrison JL, Muhlhausler BS, Molloy PL. Recent developments on the role of epigenetics in obesity and metabolic disease. Clin Epigenetics 2015; 7:66. [PMID: 27408648 PMCID: PMC4940755 DOI: 10.1186/s13148-015-0101-5] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 06/29/2015] [Indexed: 12/20/2022] Open
Abstract
The increased prevalence of obesity and related comorbidities is a major public health problem. While genetic factors undoubtedly play a role in determining individual susceptibility to weight gain and obesity, the identified genetic variants only explain part of the variation. This has led to growing interest in understanding the potential role of epigenetics as a mediator of gene-environment interactions underlying the development of obesity and its associated comorbidities. Initial evidence in support of a role of epigenetics in obesity and type 2 diabetes mellitus (T2DM) was mainly provided by animal studies, which reported epigenetic changes in key metabolically important tissues following high-fat feeding and epigenetic differences between lean and obese animals and by human studies which showed epigenetic changes in obesity and T2DM candidate genes in obese/diabetic individuals. More recently, advances in epigenetic methodologies and the reduced cost of epigenome-wide association studies (EWAS) have led to a rapid expansion of studies in human populations. These studies have also reported epigenetic differences between obese/T2DM adults and healthy controls and epigenetic changes in association with nutritional, weight loss, and exercise interventions. There is also increasing evidence from both human and animal studies that the relationship between perinatal nutritional exposures and later risk of obesity and T2DM may be mediated by epigenetic changes in the offspring. The aim of this review is to summarize the most recent developments in this rapidly moving field, with a particular focus on human EWAS and studies investigating the impact of nutritional and lifestyle factors (both pre- and postnatal) on the epigenome and their relationship to metabolic health outcomes. The difficulties in distinguishing consequence from causality in these studies and the critical role of animal models for testing causal relationships and providing insight into underlying mechanisms are also addressed. In summary, the area of epigenetics and metabolic health has seen rapid developments in a short space of time. While the outcomes to date are promising, studies are ongoing, and the next decade promises to be a time of productive research into the complex interactions between the genome, epigenome, and environment as they relate to metabolic disease.
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Affiliation(s)
- Susan J van Dijk
- CSIRO Food and Nutrition Flagship, PO Box 52, North Ryde, NSW 1670 Australia
| | - Ross L Tellam
- CSIRO Agriculture Flagship, 306 Carmody Road, St Lucia, QLD 4067 Australia
| | - Janna L Morrison
- Early Origins of Adult Health Research Group, School of Pharmacy and Medical Sciences, Sansom Institute for Health Research, University of South Australia, GPO Box 2471, Adelaide, SA 5001 Australia
| | - Beverly S Muhlhausler
- FOODplus Research Centre, Waite Campus, The University of Adelaide, PMB 1, Glen Osmond, SA 5064 Australia.,Women's and Children's Health Research Institute, 72 King William Road, North Adelaide, SA 5006 Australia
| | - Peter L Molloy
- CSIRO Food and Nutrition Flagship, PO Box 52, North Ryde, NSW 1670 Australia
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12
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Peters TJ, Buckley MJ, Statham AL, Pidsley R, Samaras K, V Lord R, Clark SJ, Molloy PL. De novo identification of differentially methylated regions in the human genome. Epigenetics Chromatin 2015; 8:6. [PMID: 25972926 PMCID: PMC4429355 DOI: 10.1186/1756-8935-8-6] [Citation(s) in RCA: 575] [Impact Index Per Article: 63.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 12/17/2014] [Indexed: 02/07/2023] Open
Abstract
Background The identification and characterisation of differentially methylated regions (DMRs) between phenotypes in the human genome is of prime interest in epigenetics. We present a novel method, DMRcate, that fits replicated methylation measurements from the Illumina HM450K BeadChip (or 450K array) spatially across the genome using a Gaussian kernel. DMRcate identifies and ranks the most differentially methylated regions across the genome based on tunable kernel smoothing of the differential methylation (DM) signal. The method is agnostic to both genomic annotation and local change in the direction of the DM signal, removes the bias incurred from irregularly spaced methylation sites, and assigns significance to each DMR called via comparison to a null model. Results We show that, for both simulated and real data, the predictive performance of DMRcate is superior to those of Bumphunter and Probe Lasso, and commensurate with that of comb-p. For the real data, we validate all array-derived DMRs from the candidate methods on a suite of DMRs derived from whole-genome bisulfite sequencing called from the same DNA samples, using two separate phenotype comparisons. Conclusions The agglomeration of genomically localised individual methylation sites into discrete DMRs is currently best served by a combination of DM-signal smoothing and subsequent threshold specification. The findings also suggest the design of the 450K array shows preference for CpG sites that are more likely to be differentially methylated, but its overall coverage does not adequately reflect the depth and complexity of methylation signatures afforded by sequencing. For the convenience of the research community we have created a user-friendly R software package called DMRcate, downloadable from Bioconductor and compatible with existing preprocessing packages, which allows others to apply the same DMR-finding method on 450K array data. Electronic supplementary material The online version of this article (doi:10.1186/1756-8935-8-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Timothy J Peters
- CSIRO Digital Productivity Flagship, Riverside Life Sciences Centre, 11 Julius Avenue, North Ryde, New South Wales, 2113 Australia
| | - Michael J Buckley
- CSIRO Digital Productivity Flagship, Riverside Life Sciences Centre, 11 Julius Avenue, North Ryde, New South Wales, 2113 Australia
| | - Aaron L Statham
- Epigenetics Program, Garvan Institute of Medical Research, Sydney, Australia
| | - Ruth Pidsley
- Epigenetics Program, Garvan Institute of Medical Research, Sydney, Australia
| | | | - Reginald V Lord
- School of Medicine, University of Notre Dame, Darlinghurst, New South Wales 2010 Australia
| | - Susan J Clark
- Epigenetics Program, Garvan Institute of Medical Research, Sydney, Australia ; St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Darlinghurst, New South Wales 2010 Australia
| | - Peter L Molloy
- CSIRO Food and Nutrition Flagship, Riverside Life Sciences Centre, 11 Julius Avenue, Sydney, Australia
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13
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Mahon KL, Qu W, Devaney J, Paul C, Castillo L, Wykes RJ, Chatfield MD, Boyer MJ, Stockler MR, Marx G, Gurney H, Mallesara G, Molloy PL, Horvath LG, Clark SJ. Methylated Glutathione S-transferase 1 (mGSTP1) is a potential plasma free DNA epigenetic marker of prognosis and response to chemotherapy in castrate-resistant prostate cancer. Br J Cancer 2014; 111:1802-9. [PMID: 25144624 PMCID: PMC4453725 DOI: 10.1038/bjc.2014.463] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 07/16/2014] [Accepted: 07/24/2014] [Indexed: 12/25/2022] Open
Abstract
Background: Glutathione S-transferase 1 (GSTP1) inactivation is associated with CpG island promoter hypermethylation in the majority of prostate cancers (PCs). This study assessed whether the level of circulating methylated GSTP1 (mGSTP1) in plasma DNA is associated with chemotherapy response and overall survival (OS). Methods: Plasma samples were collected prospectively from a Phase I exploratory cohort of 75 men with castrate-resistant PC (CRPC) and a Phase II independent validation cohort (n=51). mGSTP1 levels in free DNA were measured using a sensitive methylation-specific PCR assay. Results: The Phase I cohort identified that detectable baseline mGSTP1 DNA was associated with poorer OS (HR, 4.2 95% CI 2.1–8.2; P<0.0001). A decrease in mGSTP1 DNA levels after cycle 1 was associated with a PSA response (P=0.008). In the Phase II cohort, baseline mGSTP1 DNA was a stronger predictor of OS than PSA change after 3 months (P=0.02). Undetectable plasma mGSTP1 after one cycle of chemotherapy was associated with PSA response (P=0.007). Conclusions: We identified plasma mGSTP1 DNA as a potential prognostic marker in men with CRPC as well as a potential surrogate therapeutic efficacy marker for chemotherapy and corroborated these findings in an independent Phase II cohort. Prospective Phase III assessment of mGSTP1 levels in plasma DNA is now warranted.
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Affiliation(s)
- K L Mahon
- 1] Chris O'Brien Lifehouse, Missenden Rd, Camperdown, New South Wales, 2050, Australia [2] Cancer Research Division, Garvan Institute of Medical Research/The Kinghorn Cancer Centre, Darlinghurst, New South Wales, 2010, Australia [3] Sydney Medical School, University of Sydney, Camperdown, New South Wales, 2050, Australia
| | - W Qu
- Cancer Research Division, Garvan Institute of Medical Research/The Kinghorn Cancer Centre, Darlinghurst, New South Wales, 2010, Australia
| | - J Devaney
- Cancer Research Division, Garvan Institute of Medical Research/The Kinghorn Cancer Centre, Darlinghurst, New South Wales, 2010, Australia
| | - C Paul
- Cancer Research Division, Garvan Institute of Medical Research/The Kinghorn Cancer Centre, Darlinghurst, New South Wales, 2010, Australia
| | - L Castillo
- Cancer Research Division, Garvan Institute of Medical Research/The Kinghorn Cancer Centre, Darlinghurst, New South Wales, 2010, Australia
| | - R J Wykes
- Royal Prince Alfred Hospital, Missenden Rd, Camperdown, New South Wales, 2050, Australia
| | - M D Chatfield
- Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - M J Boyer
- 1] Chris O'Brien Lifehouse, Missenden Rd, Camperdown, New South Wales, 2050, Australia [2] Sydney Medical School, University of Sydney, Camperdown, New South Wales, 2050, Australia [3] Royal Prince Alfred Hospital, Missenden Rd, Camperdown, New South Wales, 2050, Australia
| | - M R Stockler
- 1] Chris O'Brien Lifehouse, Missenden Rd, Camperdown, New South Wales, 2050, Australia [2] Sydney Medical School, University of Sydney, Camperdown, New South Wales, 2050, Australia [3] NHMRC Clinical Trials Centre, University of Sydney, New South Wales, 2050, Australia
| | - G Marx
- 1] Sydney Medical School, University of Sydney, Camperdown, New South Wales, 2050, Australia [2] Northern Haematology and Oncology Group, SAN Clinic, Wahroonga, New South Wales, 2076, Australia
| | - H Gurney
- 1] Sydney Medical School, University of Sydney, Camperdown, New South Wales, 2050, Australia [2] Westmead Hospital, Sydney, New South Wales, Australia
| | - G Mallesara
- Calvary Mater Newcastle, New South Wales, Australia
| | - P L Molloy
- CSIRO Animal, Food and Health Sciences, North Ryde, New South Wales, 2113, Australia
| | - L G Horvath
- 1] Chris O'Brien Lifehouse, Missenden Rd, Camperdown, New South Wales, 2050, Australia [2] Cancer Research Division, Garvan Institute of Medical Research/The Kinghorn Cancer Centre, Darlinghurst, New South Wales, 2010, Australia [3] Sydney Medical School, University of Sydney, Camperdown, New South Wales, 2050, Australia [4] Royal Prince Alfred Hospital, Missenden Rd, Camperdown, New South Wales, 2050, Australia
| | - S J Clark
- 1] Cancer Research Division, Garvan Institute of Medical Research/The Kinghorn Cancer Centre, Darlinghurst, New South Wales, 2010, Australia [2] St Vincent's Clinical School, University of NSW, Sydney, 2010, New South Wales, Australia
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14
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Pedersen SK, Mitchell SM, Graham LD, McEvoy A, Thomas ML, Baker RT, Ross JP, Xu ZZ, Ho T, LaPointe LC, Young GP, Molloy PL. CAHM, a long non-coding RNA gene hypermethylated in colorectal neoplasia. Epigenetics 2014; 9:1071-82. [PMID: 24799664 PMCID: PMC4164492 DOI: 10.4161/epi.29046] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The CAHM gene (Colorectal Adenocarcinoma HyperMethylated), previously LOC100526820, is located on chromosome 6, hg19 chr6:163 834 097–163 834 982. It lacks introns, encodes a long non-coding RNA (lncRNA) and is located adjacent to the gene QKI, which encodes an RNA binding protein. Deep bisulphite sequencing of ten colorectal cancer (CRC) and matched normal tissues demonstrated frequent hypermethylation within the CAHM gene in cancer. A quantitative methylation-specific PCR (qMSP) was used to characterize additional tissue samples. With a threshold of 5% methylation, the CAHM assay was positive in 2/26 normal colorectal tissues (8%), 17/21 adenomas (81%), and 56/79 CRC samples (71%). A reverse transcriptase-qPCR assay showed that CAHM RNA levels correlated negatively with CAHM % methylation, and therefore CAHM gene expression is typically decreased in CRC. The CAHM qMSP assay was applied to DNA isolated from plasma specimens from 220 colonoscopy-examined patients. Using a threshold of 3 pg methylated genomic DNA per mL plasma, methylated CAHM sequences were detected in the plasma DNA of 40/73 (55%) of CRC patients compared with 3/73 (4%) from subjects with adenomas and 5/74 (7%) from subjects without neoplasia. Both the frequency of detection and the amount of methylated CAHM DNA released into plasma increased with increasing cancer stage. Methylated CAHM DNA shows promise as a plasma biomarker for use in screening for CRC.
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Affiliation(s)
| | - Susan M Mitchell
- CSIRO Preventative Health Flagship; Animal, Food & Health Sciences Division; North Ryde, NSW Australia
| | - Lloyd D Graham
- CSIRO Preventative Health Flagship; Animal, Food & Health Sciences Division; North Ryde, NSW Australia
| | - Aidan McEvoy
- Clinical Genomics Pty Ltd; North Ryde, NSW Australia
| | | | - Rohan T Baker
- Clinical Genomics Pty Ltd; North Ryde, NSW Australia
| | - Jason P Ross
- CSIRO Preventative Health Flagship; Animal, Food & Health Sciences Division; North Ryde, NSW Australia
| | - Zheng-Zhou Xu
- CSIRO Preventative Health Flagship; Animal, Food & Health Sciences Division; North Ryde, NSW Australia
| | - Thu Ho
- CSIRO Preventative Health Flagship; Animal, Food & Health Sciences Division; North Ryde, NSW Australia
| | | | - Graeme P Young
- Flinders Centre for Innovation in Cancer; Flinders University (FMC); Adelaide, SA Australia
| | - Peter L Molloy
- CSIRO Preventative Health Flagship; Animal, Food & Health Sciences Division; North Ryde, NSW Australia
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15
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Mitchell SM, Ross JP, Drew HR, Ho T, Brown GS, Saunders NFW, Duesing KR, Buckley MJ, Dunne R, Beetson I, Rand KN, McEvoy A, Thomas ML, Baker RT, Wattchow DA, Young GP, Lockett TJ, Pedersen SK, LaPointe LC, Molloy PL. A panel of genes methylated with high frequency in colorectal cancer. BMC Cancer 2014; 14:54. [PMID: 24485021 PMCID: PMC3924905 DOI: 10.1186/1471-2407-14-54] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 01/20/2014] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The development of colorectal cancer (CRC) is accompanied by extensive epigenetic changes, including frequent regional hypermethylation particularly of gene promoter regions. Specific genes, including SEPT9, VIM1 and TMEFF2 become methylated in a high fraction of cancers and diagnostic assays for detection of cancer-derived methylated DNA sequences in blood and/or fecal samples are being developed. There is considerable potential for the development of new DNA methylation biomarkers or panels to improve the sensitivity and specificity of current cancer detection tests. METHODS Combined epigenomic methods - activation of gene expression in CRC cell lines following DNA demethylating treatment, and two novel methods of genome-wide methylation assessment - were used to identify candidate genes methylated in a high fraction of CRCs. Multiplexed amplicon sequencing of PCR products from bisulfite-treated DNA of matched CRC and non-neoplastic tissue as well as healthy donor peripheral blood was performed using Roche 454 sequencing. Levels of DNA methylation in colorectal tissues and blood were determined by quantitative methylation specific PCR (qMSP). RESULTS Combined analyses identified 42 candidate genes for evaluation as DNA methylation biomarkers. DNA methylation profiles of 24 of these genes were characterised by multiplexed bisulfite-sequencing in ten matched tumor/normal tissue samples; differential methylation in CRC was confirmed for 23 of these genes. qMSP assays were developed for 32 genes, including 15 of the sequenced genes, and used to quantify methylation in tumor, adenoma and non-neoplastic colorectal tissue and from healthy donor peripheral blood. 24 of the 32 genes were methylated in >50% of neoplastic samples, including 11 genes that were methylated in 80% or more CRCs and a similar fraction of adenomas. CONCLUSIONS This study has characterised a panel of 23 genes that show elevated DNA methylation in >50% of CRC tissue relative to non-neoplastic tissue. Six of these genes (SOX21, SLC6A15, NPY, GRASP, ST8SIA1 and ZSCAN18) show very low methylation in non-neoplastic colorectal tissue and are candidate biomarkers for stool-based assays, while 11 genes (BCAT1, COL4A2, DLX5, FGF5, FOXF1, FOXI2, GRASP, IKZF1, IRF4, SDC2 and SOX21) have very low methylation in peripheral blood DNA and are suitable for further evaluation as blood-based diagnostic markers.
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Affiliation(s)
- Susan M Mitchell
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Jason P Ross
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Horace R Drew
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Thu Ho
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Glenn S Brown
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Neil FW Saunders
- CSIRO Computational Informatics, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Konsta R Duesing
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Michael J Buckley
- CSIRO Computational Informatics, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Rob Dunne
- CSIRO Computational Informatics, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Iain Beetson
- Clinical Genomics Pty Ltd, North Ryde, NSW, Australia
| | - Keith N Rand
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | - Aidan McEvoy
- Clinical Genomics Pty Ltd, North Ryde, NSW, Australia
| | | | - Rohan T Baker
- Clinical Genomics Pty Ltd, North Ryde, NSW, Australia
| | - David A Wattchow
- Flinders Centre for Innovation in Cancer, Flinders University (FMC), Adelaide, SA, Australia
| | - Graeme P Young
- Flinders Centre for Innovation in Cancer, Flinders University (FMC), Adelaide, SA, Australia
| | - Trevor J Lockett
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
| | | | | | - Peter L Molloy
- CSIRO Animal, Food & Health Sciences, Preventative Health Flagship, North Ryde, NSW, Australia
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Ellis BC, Graham LD, Molloy PL. CRNDE, a long non-coding RNA responsive to insulin/IGF signaling, regulates genes involved in central metabolism. Biochim Biophys Acta 2013; 1843:372-86. [PMID: 24184209 DOI: 10.1016/j.bbamcr.2013.10.016] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 10/04/2013] [Accepted: 10/21/2013] [Indexed: 12/18/2022]
Abstract
Colorectal neoplasia differentially expressed (CRNDE) is a novel gene that is activated early in colorectal cancer but whose regulation and functions are unknown. CRNDE transcripts are recognized as long non-coding RNAs (lncRNAs), which potentially interact with chromatin-modifying complexes to regulate gene expression via epigenetic changes. Complex alternative splicing results in numerous transcripts from this gene, and we have identified novel transcripts containing a highly-conserved sequence within intron 4 ("gVC-In4"). In colorectal cancer cells, we demonstrate that treatment with insulin and insulin-like growth factors (IGF) repressed CRNDE nuclear transcripts, including those encompassing gVC-In4. These repressive effects were negated by use of inhibitors against either the PI3K/Akt/mTOR pathway or Raf/MAPK pathway, suggesting CRNDE is a downstream target of both signaling cascades. Expression array analyses revealed that siRNA-mediated knockdown of gVC-In4 transcripts affected the expression of many genes, which showed correlation with insulin/IGF signaling pathway components and responses, including glucose and lipid metabolism. Some of the genes are identical to those affected by insulin treatment in the same cell line. The results suggest that CRNDE expression promotes the metabolic changes by which cancer cells switch to aerobic glycolysis (Warburg effect). This is the first report of a lncRNA regulated by insulin/IGFs, and our findings indicate a role for CRNDE nuclear transcripts in regulating cellular metabolism which may correlate with their upregulation in colorectal cancer.
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Affiliation(s)
- Blake C Ellis
- CSIRO Animal, Food and Health Sciences, Preventative Health Flagship, Commonwealth Scientific and Industrial Research Organization, Sydney, NSW 2113 Australia.
| | - Lloyd D Graham
- CSIRO Animal, Food and Health Sciences, Preventative Health Flagship, Commonwealth Scientific and Industrial Research Organization, Sydney, NSW 2113 Australia.
| | - Peter L Molloy
- CSIRO Animal, Food and Health Sciences, Preventative Health Flagship, Commonwealth Scientific and Industrial Research Organization, Sydney, NSW 2113 Australia.
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17
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Rand KN, Young GP, Ho T, Molloy PL. Sensitive and selective amplification of methylated DNA sequences using helper-dependent chain reaction in combination with a methylation-dependent restriction enzymes. Nucleic Acids Res 2013; 41:e15. [PMID: 22965136 PMCID: PMC3592453 DOI: 10.1093/nar/gks831] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 07/18/2012] [Accepted: 08/09/2012] [Indexed: 12/25/2022] Open
Abstract
We have developed a novel technique for specific amplification of rare methylated DNA fragments in a high background of unmethylated sequences that avoids the need of bisulphite conversion. The methylation-dependent restriction enzyme GlaI is used to selectively cut methylated DNA. Then targeted fragments are tagged using specially designed 'helper' oligonucleotides that are also used to maintain selection in subsequent amplification cycles in a process called 'helper-dependent chain reaction'. The process uses disabled primers called 'drivers' that can only prime on each cycle if the helpers recognize specific sequences within the target amplicon. In this way, selection for the sequence of interest is maintained throughout the amplification, preventing amplification of unwanted sequences. Here we show how the method can be applied to methylated Septin 9, a promising biomarker for early diagnosis of colorectal cancer. The GlaI digestion and subsequent amplification can all be done in a single tube. A detection sensitivity of 0.1% methylated DNA in a background of unmethylated DNA was achieved, which was similar to the well-established Heavy Methyl method that requires bisulphite-treated DNA.
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Affiliation(s)
- Keith N Rand
- CSIRO Animal, Food and Health Sciences, Preventative Health Flagship, North Ryde, NSW 1670, Australia.
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18
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Ross JP, Shaw JM, Molloy PL. Identification of differentially methylated regions using streptavidin bisulfite ligand methylation enrichment (SuBLiME), a new method to enrich for methylated DNA prior to deep bisulfite genomic sequencing. Epigenetics 2012; 8:113-27. [PMID: 23257838 PMCID: PMC3549874 DOI: 10.4161/epi.23330] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We have developed a method that enriches for methylated cytosines by capturing the fraction of bisulfite-treated DNA with unconverted cytosines. The method, called streptavidin bisulfite ligand methylation enrichment (SuBLiME), involves the specific labeling (using a biotin-labeled nucleotide ligand) of methylated cytosines in bisulfite-converted DNA. This step is then followed by affinity capture, using streptavidin-coupled magnetic beads. SuBLiME is highly adaptable and can be combined with deep sequencing library generation and/or genomic complexity-reduction. In this pilot study, we enriched methylated DNA from Csp6I-cut complexity-reduced genomes of colorectal cancer cell lines (HCT-116, HT-29 and SW-480) and normal blood leukocytes with the aim of discovering colorectal cancer biomarkers. Enriched libraries were sequenced with SOLiD-3 technology. In pairwise comparisons, we scored a total of 1,769 gene loci and 33 miRNA loci as differentially methylated between the cell lines and leukocytes. Of these, 516 loci were differently methylated in at least two promoter-proximal CpG sites over two discrete Csp6I fragments. Identified methylated gene loci were associated with anatomical development, differentiation and cell signaling. The data correlated with good agreement to a number of published colorectal cancer DNA methylation biomarkers and genomic data sets. SuBLiME is effective in the enrichment of methylated nucleic acid and in the detection of known and novel biomarkers.
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Affiliation(s)
- Jason P Ross
- Preventative Health National Research Flagship, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Sydney, NSW, Australia.
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19
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Ellis BC, Molloy PL, Graham LD. CRNDE: A Long Non-Coding RNA Involved in CanceR, Neurobiology, and DEvelopment. Front Genet 2012; 3:270. [PMID: 23226159 PMCID: PMC3509318 DOI: 10.3389/fgene.2012.00270] [Citation(s) in RCA: 174] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 11/07/2012] [Indexed: 12/25/2022] Open
Abstract
CRNDE is the gene symbol for Colorectal Neoplasia Differentially Expressed (non-protein-coding), a long non-coding RNA (lncRNA) gene that expresses multiple splice variants and displays a very tissue-specific pattern of expression. CRNDE was initially identified as a lncRNA whose expression is highly elevated in colorectal cancer, but it is also upregulated in many other solid tumors and in leukemias. Indeed, CRNDE is the most upregulated lncRNA in gliomas and here, as in other cancers, it is associated with a "stemness" signature. CRNDE is expressed in specific regions within the human and mouse brain; the mouse ortholog is high in induced pluripotent stem cells and increases further during neuronal differentiation. We suggest that CRNDE is a multifunctional lncRNA whose different splice forms provide specific functional scaffolds for regulatory complexes, such as the polycomb repressive complex 2 (PRC2) and CoREST chromatin-modifying complexes, which CRNDE helps pilot to target genes.
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Affiliation(s)
- Blake C Ellis
- CSIRO Animal, Food and Health Sciences, Preventative Health Flagship, Commonwealth Scientific and Industrial Research Organisation Sydney, NSW, Australia
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20
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Graham LD, Pedersen SK, Brown GS, Ho T, Kassir Z, Moynihan AT, Vizgoft EK, Dunne R, Pimlott L, Young GP, Lapointe LC, Molloy PL. Colorectal Neoplasia Differentially Expressed (CRNDE), a Novel Gene with Elevated Expression in Colorectal Adenomas and Adenocarcinomas. Genes Cancer 2012; 2:829-40. [PMID: 22393467 DOI: 10.1177/1947601911431081] [Citation(s) in RCA: 208] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 11/02/2011] [Indexed: 12/13/2022] Open
Abstract
An uncharacterized gene locus (Chr16:hCG_1815491), now named colorectal neoplasia differentially expressed (gene symbol CRNDE), is activated early in colorectal neoplasia. The locus is unrelated to any known protein-coding gene. Microarray analysis of 454 tissue specimens (discovery) and 68 previously untested specimens (validation) showed elevated expression of CRNDE in >90% of colorectal adenomas and adenocarcinomas. These findings were confirmed and extended by exon microarray studies and RT-PCR assays. CRNDE transcription start sites were identified in CaCo2 and HCT116 cells by 5'-RACE. The major transcript isoforms in colorectal cancer (CRC) cell lines and colorectal tissue are CRNDE-a, -b, -d, -e, -f, -h, and -j. Except for CRNDE-d, the known CRNDE splice variants are upregulated in neoplastic colorectal tissue; expression levels for CRNDE-h alone demonstrate a sensitivity of 95% and specificity of 96% for adenoma versus normal tissue. A quantitative RT-PCR assay measuring CRNDE-h RNA levels in plasma was (with a threshold of 2(-ΔCt) = 2.8) positive for 13 of 15 CRC patients (87%) but only 1 of 15 healthy individuals (7%). We conclude that individual CRNDE transcripts show promise as tissue and plasma biomarkers, potentially exhibiting high sensitivity and specificity for colorectal adenomas and cancers.
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Affiliation(s)
- Lloyd D Graham
- CSIRO Food and Nutritional Sciences, Sydney, NSW, Australia
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21
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Liu J, Hesson LB, Meagher AP, Bourke MJ, Hawkins NJ, Rand KN, Molloy PL, Pimanda JE, Ward RL. Relative distribution of folate species is associated with global DNA methylation in human colorectal mucosa. Cancer Prev Res (Phila) 2012; 5:921-9. [PMID: 22609762 DOI: 10.1158/1940-6207.capr-11-0577] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Folate exists as functionally diverse species within cells. Although folate deficiency may contribute to DNA hypomethylation in colorectal cancer, findings on the association between total folate concentration and global DNA methylation have been inconsistent. This study determined global, LINE-1, and Alu DNA methylation in blood and colon of healthy and colorectal cancer patients and their relationship to folate distribution. Blood and normal mucosa from 112 colorectal cancer patients and 114 healthy people were analyzed for global DNA methylation and folate species distribution using liquid chromatography tandem mass spectrometry. Repeat element methylation was determined using end-specific PCR. Colorectal mucosa had lower global and repeat element DNA methylation compared with peripheral blood (P < 0.0001). After adjusting for age, sex and smoking history, global but not repeat element methylation was marginally higher in normal mucosa from colorectal cancer patients compared with healthy individuals. Colorectal mucosa from colorectal cancer subjects had lower 5-methyltetrahydrofolate and higher tetrahydrofolate and formyltetrahydrofolate levels than blood from the same individual. Blood folate levels should not be used as a surrogate for the levels in colorectal mucosa because there are marked differences in folate species distribution between the two tissues. Similarly, repeat element methylation is not a good surrogate measure of global DNA methylation in both blood and colonic mucosa. There was no evidence that mucosal global DNA methylation or folate distribution was related to the presence of cancer per se, suggesting that if abnormalities exist, they are confined to individual cells rather than the entire colon.
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Affiliation(s)
- Jia Liu
- Lowy Cancer Research Centre and Prince of Wales Clinical School, Australia
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22
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Conlon MA, Kerr CA, McSweeney CS, Dunne RA, Shaw JM, Kang S, Bird AR, Morell MK, Lockett TJ, Molloy PL, Regina A, Toden S, Clarke JM, Topping DL. Resistant starches protect against colonic DNA damage and alter microbiota and gene expression in rats fed a Western diet. J Nutr 2012; 142:832-40. [PMID: 22457395 PMCID: PMC3327741 DOI: 10.3945/jn.111.147660] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Resistant starch (RS), fed as high amylose maize starch (HAMS) or butyrylated HAMS (HAMSB), opposes dietary protein-induced colonocyte DNA damage in rats. In this study, rats were fed Western-type diets moderate in fat (19%) and protein (20%) containing digestible starches [low amylose maize starch (LAMS) or low amylose whole wheat (LAW)] or RS [HAMS, HAMSB, or a whole high amylose wheat (HAW) generated by RNA interference] for 11 wk (n = 10/group). A control diet included 7% fat, 13% protein, and LAMS. Colonocyte DNA single-strand breaks (SSB) were significantly higher (by 70%) in rats fed the Western diet containing LAMS relative to controls. Dietary HAW, HAMS, and HAMSB opposed this effect while raising digesta levels of SCFA and lowering ammonia and phenol levels. SSB correlated inversely with total large bowel SCFA, including colonic butyrate concentration (R(2) = 0.40; P = 0.009), and positively with colonic ammonia concentration (R(2) = 0.40; P = 0.014). Analysis of gut microbiota populations using a phylogenetic microarray revealed profiles that fell into 3 distinct groups: control and LAMS; HAMS and HAMSB; and LAW and HAW. The expression of colonic genes associated with the maintenance of genomic integrity (notably Mdm2, Top1, Msh3, Ung, Rere, Cebpa, Gmnn, and Parg) was altered and varied with RS source. HAW is as effective as HAMS and HAMSB in opposing diet-induced colonic DNA damage in rats, but their effects on the large bowel microbiota and colonocyte gene expression differ, possibly due to the presence of other fiber components in HAW.
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Affiliation(s)
- Michael A. Conlon
- CSIRO Preventative Health,Food Futures National Research Flagships, and,CSIRO Food and Nutritional Sciences, Adelaide, South Australia, Australia
| | - Caroline A. Kerr
- CSIRO Preventative Health,CSIRO Food and Nutritional Sciences, North Ryde, New South Wales, Australia
| | | | - Robert A. Dunne
- CSIRO Preventative Health,CSIRO Mathematics, Informatics and Statistics, Glen Osmond, South Australia, Australia; and
| | - Janet M. Shaw
- CSIRO Preventative Health,CSIRO Food and Nutritional Sciences, North Ryde, New South Wales, Australia
| | - Seungha Kang
- CSIRO Preventative Health,CSIRO Livestock Industries, St Lucia, Queensland, Australia
| | - Anthony R. Bird
- CSIRO Preventative Health,Food Futures National Research Flagships, and,CSIRO Food and Nutritional Sciences, Adelaide, South Australia, Australia
| | - Matthew K. Morell
- Food Futures National Research Flagships, and,CSIRO Plant Industry, Black Mountain, Australian Capital Territory, Australia
| | - Trevor J. Lockett
- CSIRO Preventative Health,CSIRO Food and Nutritional Sciences, North Ryde, New South Wales, Australia
| | - Peter L. Molloy
- CSIRO Preventative Health,CSIRO Food and Nutritional Sciences, North Ryde, New South Wales, Australia
| | - Ahmed Regina
- Food Futures National Research Flagships, and,CSIRO Plant Industry, Black Mountain, Australian Capital Territory, Australia
| | - Shusuke Toden
- CSIRO Preventative Health,Food Futures National Research Flagships, and,CSIRO Food and Nutritional Sciences, Adelaide, South Australia, Australia
| | - Julie M. Clarke
- CSIRO Preventative Health,CSIRO Food and Nutritional Sciences, Adelaide, South Australia, Australia
| | - David L. Topping
- CSIRO Preventative Health,Food Futures National Research Flagships, and,CSIRO Food and Nutritional Sciences, Adelaide, South Australia, Australia,To whom correspondence should be addressed. E-mail:
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23
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Abstract
An important feature of cancer development and progression is the change in DNA methylation patterns, characterized by the hypermethylation of specific genes concurrently with an overall decrease in the level of 5-methylcytosine. Hypomethylation of the genome can affect both single-copy genes, repeat DNA sequences and transposable elements, and is highly variable among and within cancer types. Here, we review our current understanding of genome hypomethylation in cancer, with a particular focus on hypomethylation of the different classes and families of repeat sequences. The emerging data provide insights into the importance of methylation of different repeat families in the maintenance of chromosome structural integrity and the fidelity of normal transcriptional regulation. We also consider the events underlying cancer-associated hypomethylation and the potential for the clinical use of characteristic DNA methylation changes in diagnosis, prognosis or classification of tumors.
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Affiliation(s)
- Jason P Ross
- Commonwealth Scientific & Industrial Research Organisation, Food & Nutritional Science, Preventative Health National Research Flagship, North Ryde, NSW 1670, Australia
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24
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Liu J, Hesson LB, Meagher AP, Bourke MJ, Hawkins NJ, Rand KN, Molloy PL, Pimanda JE, Ward RL. Abstract 3125: Relative distribution of folate species is associated with global DNA methylation in human colorectal mucosa. Cancer Res 2012. [DOI: 10.1158/1538-7445.am2012-3125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Folate, an important cellular methyl donor, exists as functionally diverse species within cells. Folate deficiency is thought to contribute to DNA hypomethylation in colorectal cancer (CRC) however findings on the relationship between total folate concentration and global DNA methylation have been inconsistent. The aim of this study was to determine if global DNA methylation in blood and colorectal mucosa from healthy and CRC patients is related to folate species distribution. Blood and colorectal mucosa was collected from 112 CRC patients, 114 healthy individuals and 82 low folate individuals. Global methylation and folate was determined using liquid chromatography tandem mass spectrometry and repeat element methylation was determined using end-specific polymerase chain reaction. In colorectal mucosa mean global methylation was 8% lower compared to blood while LINE-1 and Alu elements were 3.3-fold and 1.9-fold hypomethylated respectively (P <0.0001). After adjusting for age and smoking, statistically significant but small (2.2%) differences in global but not repeat methylation were found in normal colorectal mucosa from CRC patients compared to healthy individuals. Low folate patients had 18% lower blood 5-methyltetrahydrofolate distribution (P <0.0001) and global (P =0.001) and LINE-1 demethylation (P <0.0001) compared to healthy individuals. The colorectal mucosa from cancer and healthy patients had an altered distribution of folate species (lower 5-methyltetrahydrofolate) similar to the folate distribution found in the blood of low folate individuals. On a background of tissue specific hypomethylation, global methylation of the normal mucosa of CRC patients is similar to healthy individuals. The level of global and repeat element hypomethylation may reflect the underlying distribution of folate species rather than total folate concentration. Future studies on the relationship between methylation and folate should consider folate species distribution, and how genetic or other factors may alter this balance in different tissue types and in neoplasia.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3125. doi:1538-7445.AM2012-3125
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Affiliation(s)
- Jia Liu
- 1University of New South Wales, Australia, Sydney, Australia
| | - Luke B. Hesson
- 1University of New South Wales, Australia, Sydney, Australia
| | | | | | | | - Keith N. Rand
- 4CSIRO Food and Nutritional Sciences, North Ryde, Australia
| | | | - John E. Pimanda
- 1University of New South Wales, Australia, Sydney, Australia
| | - Robyn L. Ward
- 1University of New South Wales, Australia, Sydney, Australia
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LaPointe LC, Pedersen SK, Dunne R, Brown GS, Pimlott L, Gaur S, McEvoy A, Thomas M, Wattchow D, Molloy PL, Young GP. Discovery and validation of molecular biomarkers for colorectal adenomas and cancer with application to blood testing. PLoS One 2012; 7:e29059. [PMID: 22276102 PMCID: PMC3261845 DOI: 10.1371/journal.pone.0029059] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 11/20/2011] [Indexed: 11/24/2022] Open
Abstract
Background & Aims Colorectal cancer incidence and deaths are reduced by the detection and removal of early-stage, treatable neoplasia but we lack proven biomarkers sensitive for both cancer and pre-invasive adenomas. The aims of this study were to determine if adenomas and cancers exhibit characteristic patterns of biomarker expression and to explore whether a tissue-discovered (and validated) biomarker is differentially expressed in the plasma of patients with colorectal adenomas or cancer. Methods Candidate RNA biomarkers were identified by oligonucleotide microarray analysis of colorectal specimens (222 normal, 29 adenoma, 161 adenocarcinoma and 50 colitis) and validated in a previously untested cohort of 68 colorectal specimens using a custom-designed oligonucleotide microarray. One validated biomarker, KIAA1199, was assayed using qRT-PCR on plasma extracted RNA from 20 colonoscopy-confirmed healthy controls, 20 patients with adenoma, and 20 with cancer. Results Genome-wide analysis uncovered reproducible gene expression signatures for both adenomas and cancers compared to controls. 386/489 (79%) of the adenoma and 439/529 (83%) of the adenocarcinoma biomarkers were validated in independent tissues. We also identified genes differentially expressed in adenomas compared to cancer. KIAA1199 was selected for further analysis based on consistent up-regulation in neoplasia, previous studies and its interest as an uncharacterized gene. Plasma KIAA1199 RNA levels were significantly higher in patients with either cancer or adenoma (31/40) compared to neoplasia-free controls (6/20). Conclusions Colorectal neoplasia exhibits characteristic patterns of gene expression. KIAA1199 is differentially expressed in neoplastic tissues and KIAA1199 transcripts are more abundant in the plasma of patients with either cancer or adenoma compared to controls.
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Affiliation(s)
- Lawrence C LaPointe
- Flinders Centre for Cancer Prevention and Control, Flinders University of South Australia, Adelaide, South Australia, Australia.
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26
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Saunders IW, Ross J, Macrae F, Young GP, Blanco I, Brohede J, Brown G, Brookes D, Lockett T, Molloy PL, Moreno V, Capella G, Hannan GN. Evidence of linkage to chromosomes 10p15.3-p15.1, 14q24.3-q31.1 and 9q33.3-q34.3 in non-syndromic colorectal cancer families. Eur J Hum Genet 2011; 20:91-6. [PMID: 21829229 DOI: 10.1038/ejhg.2011.149] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Up to 25% of colorectal cancer (CRC) may be caused by inherited genetic variants that have yet to be identified. Previous genome-wide linkage studies (GWLSs) have identified a new loci postulated to contain novel CRC risk genes amongst affected families carrying no identifiable mutations in any of the known susceptibility genes for familial CRC syndromes. To undertake a new GWLS, we recruited members from 54 non-syndromic families from Australia and Spain where at least two first-degree relatives were affected by CRC. We used single-nucleotide polymorphism arrays to genotype 98 concordant affected relative pairs that were informative for linkage analyses. We tested for genome-wide significance (GWS) for linkage to CRC using a quantile statistic method, and we found that GWS was achieved at the 5% level. Independently, using the PSEUDO gene-dropping algorithm, we also found that GWS for linkage to CRC was achieved (P=0.02). Merlin non-parametric linkage analysis revealed significant linkage to CRC for chromosomal region 10p15.3-p15.1 and suggestive linkage to CRC for regions on 14q and 9q. The 10p15.3-p15.1 has not been reported to be linked to hereditary CRC in previous linkage studies, but this region does harbour the Kruppel-like factor 6 (KLF6) gene that is known to be altered in common CRC. Further studies aimed at localising the responsible genes, and characterising their function will give insight into the factors responsible for susceptibility in such families, and perhaps shed further light on the mechanisms of CRC development.
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Affiliation(s)
- Ian W Saunders
- CSIRO Preventative Health Flagship, North Ryde, New South Wales, Australia
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Ross JP, Molloy PL. Thirteenth AACR Special Conference on Cancer Epigenetics. Cancer Res 2010; 70:7372-8. [DOI: 10.1158/0008-5472.can-10-2102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The 13th American Association of Cancer Research (AACR) Special Conference on Cancer Epigenetics was held in San Juan, Puerto Rico, on January 20–23, 2010. This event heralded insights arising from the large sequencing efforts within the NIH Epigenetics Roadmap Project and the Cancer Genome Atlas Project, as well as important new discoveries in the basic biology of epigenetics and results of epigenetic drug clinical trials. A summary of the recent findings is presented here, with particular emphasis on the major themes of the conference. Cancer Res; 70(19); 7372–8. ©2010 AACR.
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Affiliation(s)
- Jason P. Ross
- Authors' Affiliation: CSIRO Food and Nutritional Sciences, Preventative Health Flagship, North Ryde, Sydney, Australia
| | - Peter L. Molloy
- Authors' Affiliation: CSIRO Food and Nutritional Sciences, Preventative Health Flagship, North Ryde, Sydney, Australia
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Molloy PL, Linnane AW, Lukins HB. Biogenesis of Mitochondria: Analysis of Deletion of Mitochondrial Antibiotic Resistance Markers in Petite Mutants of Saccharomyces cerevisiae. J Bacteriol 2010; 122:7-18. [PMID: 16559196 PMCID: PMC235632 DOI: 10.1128/jb.122.1.7-18.1975] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Yeast strains carrying markers in several mitochondrial antibiotic resistance loci have been employed in a study of the retention and deletion of mitochondrial genes in cytoplasmic petite mutants. An assessment is made of the results in terms of the probable arrangement and linkage of mitochondrial genetic markers. The results are indicative of the retention of continuous stretches of the mitochondrial genome in most petite mutants, and it is therefore possible to propose a gene order based on co-retention of different markers. The order par, mik1, oli1 is suggested from the petite studies in the case of three markers not previously assigned an unambiguous order by analysis of mitochondrial gene recombination. The frequency of separation of markers by deletion in petites was of an order similar to that obtained by recombination in polar crosses, except in the case of the ery1 and cap1 loci, which were rarely separated in petite mutants. The deletion or retention of the locus determining polarity of recombination (omega) was also demonstrated and shown to coincide with deletion or retention of the ery1, cap1 region of the mitochondrial genome. Petites retaining this region, when crossed with rho(+) strains, display features of polarity of recombination and transmission similar to the parent rho(+) strain. By contrast a petite determined to have lost the omega(+) locus did not show normal polarity of marker transmission. Differences were observed in the relative frequency of retention of markers in a number of strains and also when comparing petites derived spontaneously with those obtained after ultraviolet light mutagenesis. By contrast, a similar pattern of marker retention was seen when comparing spontaneous with ethidium bromide-induced petites.
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Affiliation(s)
- P L Molloy
- Biochemistry Department, Monash University, Clayton, Victoria, 3168, Australia
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29
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Hest BJ, Molloy PL, Frankham R, Sheldon BL. Heat shock protein gene HSP108 and a replication histone gene cluster are linked in the chicken. Anim Genet 2009. [DOI: 10.1111/j.1365-2052.1994.tb00089.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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30
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LaPointe LC, Dunne R, Brown GS, Worthley DL, Molloy PL, Wattchow D, Young GP. Map of differential transcript expression in the normal human large intestine. Physiol Genomics 2007; 33:50-64. [PMID: 18056783 DOI: 10.1152/physiolgenomics.00185.2006] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
While there is considerable research related to using differential gene expression to predict disease phenotype classification, e.g., neoplastic tissue from nonneoplastic controls, there is little understanding of the range of expression in normal tissues. Understanding patterns of gene expression in nonneoplastic tissue, including regional anatomic expression changes within an organ, is vital to understanding gene expression changes in diseased tissue. To explore the gene expression change along the proximal-distal axis of the large intestine, we analyzed microarray data in 184 normal human specimens using univariate and multivariate techniques. We found 219 probe sets that were differentially expressed between the proximal and distal colorectal regions and 115 probe sets that were differentially expressed between the terminal segments, i.e., the cecum and rectum. We did not observe any probe sets that were statistically different between any two contiguous colorectal segments. The dominant expression pattern (65 probe sets) follows a dichotomous expression pattern consistent with the midgut-hindgut embryonic origins of the gut while a second pattern (50 probe sets) depicts a gradual change in transcript levels from the cecum to the rectum. While the dichotomous pattern includes roughly equal numbers of probe sets that are elevated proximally and distally, nearly all probe sets that show a gradual change demonstrate increasing expression levels moving from proximal to distal segments. These patterns describe an expression map of individual transcript variation as well as multigene expression patterns along the large intestine. This is the first gene expression map of an entire human organ.
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Affiliation(s)
- Lawrence C LaPointe
- Department of Medicine, Flinders University of South Australia, Adelaide, Australia.
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31
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Abstract
DNA methylation is an important epigenetic modification of DNA in mammalian genomes. DNA methylation patterns are established early in development, modulated during tissue-specific differentiation and disrupted in many disease states, including cancer. To understand further the biological functions of these changes, accurate and reproducible methods are required to fully analyze the DNA methylation sequence. Here, we describe the 'gold-standard' bisulphite conversion protocol that can be used to re-sequence DNA from mammalian cells in order to determine and quantify the methylation state of a gene or genomic region at single-nucleotide resolution. The process of bisulphite treatment exploits the different sensitivities of cytosine and 5-methylcytosine (5-MeC) to deamination by bisulphite under acidic conditions--in which cytosine undergoes conversion to uracil, whereas 5-MeC remains unreactive. Bisulphite conversion of DNA, in either single tubes or in a 96-well format, can be performed in a minimum of 8 h and a maximum of 18 h, depending on the amount and quality of starting DNA.
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Affiliation(s)
- Susan J Clark
- Cancer Program, Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, Sydney, NSW 2010, Australia.
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32
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Wilson AS, Power BE, Molloy PL. DNA hypomethylation and human diseases. Biochim Biophys Acta Rev Cancer 2006; 1775:138-62. [PMID: 17045745 DOI: 10.1016/j.bbcan.2006.08.007] [Citation(s) in RCA: 324] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 08/24/2006] [Accepted: 08/27/2006] [Indexed: 12/14/2022]
Abstract
Changes in human DNA methylation patterns are an important feature of cancer development and progression and a potential role in other conditions such as atherosclerosis and autoimmune diseases (e.g., multiple sclerosis and lupus) is being recognised. The cancer genome is frequently characterised by hypermethylation of specific genes concurrently with an overall decrease in the level of 5 methyl cytosine. This hypomethylation of the genome largely affects the intergenic and intronic regions of the DNA, particularly repeat sequences and transposable elements, and is believed to result in chromosomal instability and increased mutation events. This review examines our understanding of the patterns of cancer-associated hypomethylation, and how recent advances in understanding of chromatin biology may help elucidate the mechanisms underlying repeat sequence demethylation. It also considers how global demethylation of repeat sequences including transposable elements and the site-specific hypomethylation of certain genes might contribute to the deleterious effects that ultimately result in the initiation and progression of cancer and other diseases. The use of hypomethylation of interspersed repeat sequences and genes as potential biomarkers in the early detection of tumors and their prognostic use in monitoring disease progression are also examined.
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Affiliation(s)
- Ann S Wilson
- Preventative Health National Research Flagship, North Ryde, NSW, Australia
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33
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Abstract
Differential denaturation during PCR can be used to selectively amplify unmethylated DNA from a methylated DNA background. The use of differential denaturation in PCR is particularly suited to amplification of undermethylated sequences following treatment with bisulphite, since bisulphite selectively converts cytosines to uracil while methylated cytosines remain unreactive. Thus amplicons derived from unmethylated DNA retain fewer cytosines and their lower G + C content allows for their amplification at the lower melting temperatures, while limiting amplification of the corresponding methylated amplicons (Bisulphite Differential Denaturation PCR, BDD-PCR). Selective amplification of unmethylated DNA of four human genomic regions from three genes, GSTP1, BRCA1 and MAGE-A1, is demonstrated with selectivity observed at a ratio of down to one unmethylated molecule in 10(5) methylated molecules. BDD-PCR has the potential to be used to selectively amplify and detect aberrantly demethylated genes, such as oncogenes, in cancers. Additionally BDD-PCR can be effectively utilized in improving the specificity of methylation specific PCR (MSP) by limiting amplification of DNA that is not fully converted, thus preventing misinterpretation of the methylation versus non-conversion.
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Affiliation(s)
- Keith N Rand
- Preventative Health Flagship, CSIRO Molecular and Health Technologies, North Ryde, Australia
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Rand KN, Ho T, Qu W, Mitchell SM, White R, Clark SJ, Molloy PL. Headloop suppression PCR and its application to selective amplification of methylated DNA sequences. Nucleic Acids Res 2005; 33:e127. [PMID: 16091627 PMCID: PMC1184225 DOI: 10.1093/nar/gni120] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Selective amplification in PCR is principally determined by the sequence of the primers and the temperature of the annealing step. We have developed a new PCR technique for distinguishing related sequences in which additional selectivity is dependent on sequences within the amplicon. A 5′ extension is included in one (or both) primer(s) that corresponds to sequences within one of the related amplicons. After copying and incorporation into the PCR product this sequence is then able to loop back, anneal to the internal sequences and prime to form a hairpin structure—this structure is then refractory to further amplification. Thus, amplification of sequences containing a perfect match to the 5′ extension is suppressed while amplification of sequences containing mismatches or lacking the sequence is unaffected. We have applied Headloop PCR to DNA that had been bisulphite-treated for the selective amplification of methylated sequences of the human GSTP1 gene in the presence of up to a 105-fold excess of unmethylated sequences. Headloop PCR has a potential for clinical application in the detection of differently methylated DNAs following bisulphite treatment as well as for selective amplification of sequence variants or mutants in the presence of an excess of closely related DNA sequences.
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Affiliation(s)
| | | | - Wenjia Qu
- The Garvan Institute for Medical Research384 Victoria Street, Darlinghurst NSW 2010, Australia
| | | | | | - Susan J. Clark
- The Garvan Institute for Medical Research384 Victoria Street, Darlinghurst NSW 2010, Australia
| | - Peter L. Molloy
- To whom correspondence should be addressed. Tel: +61 2 9490 5168; Fax: +61 2 9490 5010;
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35
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Wang XY, Martiniello-Wilks R, Shaw JM, Ho T, Coulston N, Cooke-Yarborough C, Molloy PL, Cameron F, Moghaddam M, Lockett TJ, Webster LK, Smith IK, Both GW, Russell PJ. Preclinical evaluation of a prostate-targeted gene-directed enzyme prodrug therapy delivered by ovine atadenovirus. Gene Ther 2005; 11:1559-67. [PMID: 15343359 DOI: 10.1038/sj.gt.3302308] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Gene-directed enzyme prodrug therapy (GDEPT) based on the Escherichia coli enzyme, purine nucleoside phosphorylase (PNP), provides a novel strategy for treating slowly growing tumors like prostate cancer (CaP). PNP converts systemically administered prodrug, fludarabine phosphate, to a toxic metabolite, 2-fluoroadenine, that kills PNP-expressing and nearby cells by inhibiting DNA, RNA and protein synthesis. Reporter gene expression directed by a hybrid prostate-directed promoter and enhancer, PSMEPb, was assayed after plasmid transfection or viral transduction of prostate and non-CaP cell lines. Androgen-sensitive (AS) LNCaP-LN3 and androgen-independent (AI) PC3 human CaP xenografts in nude mice were injected intratumorally with an ovine atadenovirus vector, OAdV623, that carries the PNP gene under PSMEPb, formulated with cationic lipid for enhanced infectivity. Fludarabine phosphate was then given intraperitoneally for 5 days at 75 mg/m2/day. PNP expression was evaluated by enzymic conversion of its substrate using reverse phase HPLC. OAdV623 showed excellent in vitro transcriptional specificity for CaP cells. In vivo, expression of PNP persisted for > 6 days after OAdV623 injection and a single treatment provided 100% increase in tumor doubling time and > 50% inhibition of tumor growth for both LNCaP-LN3 and PC3 lines, with increased tumor necrosis and apoptosis and decreased tumor cell proliferation. OAdV623 significantly suppressed the growth of AS and AI human CaP xenografts in mice.
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Affiliation(s)
- X Y Wang
- Oncology Research Centre, Prince of Wales Hospital Clinical School of Medicine, The University of New South Wales, Randwick, Australia
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Russell PJ, Hewish D, Carter T, Sterling-Levis K, Ow K, Hattarki M, Doughty L, Guthrie R, Shapira D, Molloy PL, Werkmeister JA, Kortt AA. Cytotoxic properties of immunoconjugates containing melittin-like peptide 101 against prostate cancer: in vitro and in vivo studies. Cancer Immunol Immunother 2004; 53:411-21. [PMID: 14722668 PMCID: PMC11034312 DOI: 10.1007/s00262-003-0457-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Accepted: 09/09/2003] [Indexed: 10/26/2022]
Abstract
BACKGROUND Monoclonal antibodies (MAbs) can target therapy to tumours while minimising normal tissue exposure. Efficacy of immunoconjugates containing peptide 101, designed around the first 22 amino acids of bee venom, melittin, to maintain the amphipathic helix, to enhance water solubility, and to increase hemolytic activity, was assessed in nude mice bearing subcutaneous human prostate cancer xenografts. METHODS Mouse MAbs, J591 and BLCA-38, which recognise human prostate cancer cells, were cross-linked to peptide 101 using SPDP. Tumour-bearing mice were used to compare biodistributions of radiolabeled immunoconjugates and MAb, or received multiple sequential injections of immunoconjugates. Therapeutic efficacy was assessed by delay in tumour growth and increased mouse survival. RESULTS Radiolabeled immunoconjugates and antibodies showed similar xenograft tropism. Systemic or intratumoural injection of immunoconjugates inhibited tumour growth in mice relative to carrier alone, unconjugated antibody and nonspecific antibody-peptide conjugates and improved survival for treated mice. CONCLUSIONS Immunoconjugates deliver beneficial effects; further peptide modifications may increase cytotoxicity.
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Affiliation(s)
- Pamela J Russell
- Oncology Research Centre, Department of Clinical Medicine, Prince of Wales Hospital, University of New South Wales, NSW 2031 Randwick, Australia.
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37
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Messina M, Yu DMT, Both GW, Molloy PL, Robinson BG. Calcitonin-specific transcription and splicing targets gene-directed enzyme prodrug therapy to medullary thyroid carcinoma cells. J Clin Endocrinol Metab 2003; 88:1310-8. [PMID: 12629124 DOI: 10.1210/jc.2002-021501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Recurrent and metastatic medullary thyroid carcinoma (MTC) remains difficult to treat due to its limited responsiveness to chemotherapy, radiotherapy, and imaging. To investigate an alternative therapeutic approach, we examined the feasibility of targeting gene-directed enzyme/prodrug therapy delivered by adenoviral vectors to MTC. We previously described a modified human calcitonin (CT)/CT gene-related peptide promoter that produced increased expression while maintaining specificity for MTC cells. In this study, we introduced an additional level of specificity by using cell-specific splicing and examined whether the selectivity of the gene-directed enzyme/prodrug therapy for MTC was enhanced when both the promoter and splicing features were combined in a single transcription unit. Two replication-defective adenoviruses were constructed that expressed the Escherichia coli purine nucleoside phosphorylase (PNP) gene under the transcriptional control of a modified T2 promoter (Ad.T2-PNP) or the T2 promoter in combination with a CT minigene cassette in which the PNP gene was imbedded within the CT gene exon 4 (Ad.T2-CT/PNP). The specificity of PNP expression by Ad.T2-PNP, Ad.T2-CT/PNP, and control viruses in the MTC cell line, TT, and in a panel of non-MTC cell lines was evaluated. The highest level of PNP gene expression and the most effective cell killing in the presence of prodrug occurred in TT cells infected with Ad.T2-PNP, followed by Ad.T2-CT/PNP. Infection of most non-MTC cell lines, even with high multiplicities of Ad.T2-PNP, produced only low-level PNP expression that resulted in minimal cell killing in the presence of prodrug. High-level expression of PNP and effective cell killing was observed with both adenoviral gene constructs. The highest level of cell specificity was achieved with the combined use of promoter and splicing regulation in the Ad.T2-CT/PNP virus.
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Affiliation(s)
- Marinella Messina
- Department of Cancer Genetics, Kolling Institute of Medical Research, Royal North Shore Hospital, Sydney, New South Wales, Australia 2065
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38
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Martiniello-Wilks R, Tsatralis T, Russell P, Brookes DE, Zandvliet D, Lockett LJ, Both GW, Molloy PL, Russell PJ. Transcription-targeted gene therapy for androgen-independent prostate cancer. Cancer Gene Ther 2002; 9:443-52. [PMID: 11961667 DOI: 10.1038/sj.cgt.7700451] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2002] [Indexed: 11/08/2022]
Abstract
The Escherichia coli enzyme (purine nucleoside phosphorylase, PNP) gene is delivered directly into PC3 tumors by one injection of replication-deficient human type-5 adenovirus (Ad5). Expressed PNP converts the systemically administered prodrug, 6MPDR, to a toxic purine, 6MP, causing cell death. We sought to increase the specificity of recombinant Ad vectors by controlling PNP expression with the promoter region from the androgen-dependent, prostate-specific rat probasin (Pb) gene. To increase its activity, the promoter was combined with the SV40 enhancer (SVPb). Cell lines were transfected with plasmids containing both a reporter gene, under SVPb control, and a reference gene cassette to allow normalization of expression levels. Plasmids expressed approximately 20-fold more reporter in prostate cancer than in other cells, but surprisingly, the SVPb element was both androgen-independent and retained substantial prostate specificity. Killing by Ad5-SVPb-PNP vector of cell lines cultured with 6MPDR for 6 days was 5- to 10-fold greater in prostate cancer than in liver or lung cells. In vivo, a single intratumoral injection of Ad5-SVPb-PNP (4 x 10(8) pfu), followed by 6MPDR administration twice daily for 6 days, significantly suppressed the growth of human prostate tumors in nude mice and increased their survival compared to control animals. Thus, the androgen-independent, prostate-targeting Ad5 vector reduces human prostate cancer growth significantly in vitro and in vivo. This first example of an androgen-independent vector points the way toward treatment of emerging androgen-independent prostate cancer in conjunction with hormone ablation therapy at a time when the tumor burden is low.
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39
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Schmitt JF, Millar DS, Pedersen JS, Clark SL, Venter DJ, Frydenberg M, Molloy PL, Risbridger GP. Hypermethylation of the inhibin alpha-subunit gene in prostate carcinoma. Mol Endocrinol 2002; 16:213-20. [PMID: 11818495 DOI: 10.1210/mend.16.2.0771] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Inhibin is composed of an alpha- and a beta-subunit. Transgenic studies assigned a tumor-suppressive role to the inhibin alpha-subunit, and in human prostate cancer inhibin alpha-subunit gene expression was down-regulated. This study examined the inhibin alpha-subunit gene promoter and gene locus to determine whether promoter hypermethylation or LOH occurred in DNA from prostate cancer. The 5'-untranslated region of the human inhibin alpha-subunit gene was sequenced and shown to be highly homologous to the bovine, rat, and mouse inhibin alpha-subunit promoter sequences. A 135-bp region of the human promoter sequence that continued a cluster of CpG sites was analyzed for hypermethylation. Significant (P < 0.001) hypermethylation of the inhibin alpha-subunit gene promoter occurred in DNA from Gleason pattern 3, 4, and 5 carcinomas compared with nonmalignant tissue samples. A subset of the carcinomas with a cribriform pattern were unmethylated. LOH at 2q32-36, the chromosomal region harboring the inhibin alpha-subunit gene, was observed in 42% of prostate carcinomas. These data provide the first demonstration that promoter hypermethylation and LOH are associated with the inhibin alpha-subunit gene and gene locus in prostate cancer.
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Affiliation(s)
- Jacqueline F Schmitt
- Monash Institute of Reproduction and Development, Monash University, Clayton, Victoria 3168, Australia
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40
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Uchida A, O'Keefe DS, Bacich DJ, Molloy PL, Heston WD. In vivo suicide gene therapy model using a newly discovered prostate-specific membrane antigen promoter/enhancer: a potential alternative approach to androgen deprivation therapy. Urology 2001; 58:132-9. [PMID: 11502468 DOI: 10.1016/s0090-4295(01)01256-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Prostate-specific membrane antigen (PSMA) is a type-2 membrane protein expressed in the prostate, and it is highly expressed in metastatic or poorly differentiated adenocarcinomas. Moreover, PSMA expression is upregulated by androgen deprivation. These advantages make PSMA a useful target for prostate cancer therapy, especially in combination with conventional hormonal treatment. We recently reported that a prostate-specific enhancer is present in the third intron of the PSMA gene. In this study, we have further analyzed the activity of PSMA promoter/enhancer in prostate cancer cells and cells of other tissue origins (breast cancer MCF-7, lung cancer H157, and colorectal cancer HCT8 cells), and we have examined whether this construct could be used for efficient expression of the suicide gene, cytosine deaminase (CD), in vivo. The PSMA promoter/enhancer expressed the luciferase reporter gene in the prostate cancer lines LNCaP and C4-2, with 8- to 20-fold higher expression than the simian virus 40 promoter/enhancer, although it was inactive in the other cell lines. This construct efficiently drove the suicide gene CD, sensitizing C4-2 cells to 5-fluorocytosine (5-FC) with the inhibitory concentration (IC(50)) <300 micromol/L in vitro. Athymic male nude mice bearing the transfected C4-2 cells were treated with intraperitoneal injections of either 5-FC (600 mg/kg) twice a day or saline solution for 3 weeks. C4-2 cell tumors were eliminated by 5-FC when they were expressing our therapeutic construct carrying CD under the regulatory control of the PSMA promoter/enhancer. Our results show the in vivo utility of the PSMA promoter/enhancer in a gene therapy situation targeting prostate cancer.
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Affiliation(s)
- A Uchida
- George M. O'Brien Urology Research Center, Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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41
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Watt F, Martorana A, Brookes DE, Ho T, Kingsley E, O'Keefe DS, Russell PJ, Heston WD, Molloy PL. A Tissue-Specific Enhancer of the Prostate-Specific Membrane Antigen Gene, FOLH1. Genomics 2001; 73:243-54. [PMID: 11350116 DOI: 10.1006/geno.2000.6446] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Prostate-specific membrane antigen (PSMA) is an integral membrane protein that is highly expressed on the surface of prostate epithelial cells. It is also expressed on the vascular endothelium of a number of tumor types. We have used an enhancer trap approach with randomly cleaved overlapping DNA fragments from an approximately 55-kb P1 cosmid insert encompassing the 5' half and upstream sequences of the PSMA gene (FOLH1) to isolate an enhancer that strongly activates the FOLH1 core promoter region. The enhancer (PSME) is located in the third intron about 12 kb downstream from the start site of transcription and is characterized by a 72-bp direct repeat within a 331-bp core region. The PSME activates transcription from its own and heterologous promoters in prostate cell lines; enhancement is greatest in the PSMA-expressing cell line LNCaP (>250-fold). The PSME shows essentially no activity in five nonprostate cell lines. PSME-enhanced expression is repressed in the presence of androgen, mimicking the repression of the endogenous FOLH1 gene. The data demonstrate that both cell-type specificity and androgen regulation are intrinsic properties of the enhancer. These properties make the PSME an excellent candidate for regulation of gene expression in gene therapy approaches to prostate cancer.
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Affiliation(s)
- F Watt
- CSIRO Molecular Science, North Ryde, New South Wales, 2113, Australia
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42
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Gong MC, Chang SS, Watt F, O'Keefe DS, Bacich DJ, Uchida A, Bander NH, Reuter VE, Gaudin PB, Molloy PL, Sadelian M, Heston WD. Overview of evolving strategies incorporating prostate-specific membrane antigen as target for therapy. Mol Urol 2001; 4:217-22;discussion 223. [PMID: 11062377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Prostate-specific membrane antigen (PSMA) is a potential target in prostate cancer patients because it is very highly expressed and because it has been reported to be upregulated by androgen deprivation. This overview addresses the expression of the PSMA gene in terms of the promoter and enhancer and how that may play a role in gene therapy. We also review PSMA as a target for antibodies for imaging and treatment and the development of a novel hybrid T-cell receptor that combines the specificity of anti-PSMA antibodies with that of T-cell receptor activation when introduced into primary lymphocytes by retroviral-mediated gene transfer. We also discuss our recent findings on the expression of a PSMA-like gene and how that understanding allows specific targeting of PSMA.
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MESH Headings
- Animals
- Antibodies, Neoplasm/immunology
- Antigens, Neoplasm/genetics
- Antigens, Neoplasm/immunology
- Antigens, Neoplasm/metabolism
- Antigens, Surface/genetics
- Antigens, Surface/immunology
- Antigens, Surface/metabolism
- Antineoplastic Agents/pharmacology
- Antineoplastic Agents/therapeutic use
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Carboxypeptidases/genetics
- Carboxypeptidases/immunology
- Carboxypeptidases/metabolism
- Enhancer Elements, Genetic
- Enzyme Inhibitors/pharmacology
- Female
- Genetic Therapy
- Glutamate Carboxypeptidase II
- Humans
- Male
- Prodrugs/metabolism
- Promoter Regions, Genetic
- Prostatic Neoplasms/blood supply
- Prostatic Neoplasms/enzymology
- Prostatic Neoplasms/genetics
- Prostatic Neoplasms/therapy
- Receptors, Antigen, T-Cell/immunology
- Tumor Cells, Cultured
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Affiliation(s)
- M C Gong
- Urology Department, Memorial Sloan-Kettering Cancer Center, New York, New York, USA
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43
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Abstract
BACKGROUND Prostate-specific membrane antigen (PSMA) is abundantly expressed in virtually 100% of prostate cancers and metastases. In addition, unlike prostate-specific antigen (PSA), PSMA is upregulated under conditions of androgen deprivation. Therefore, PSMA is an attractive therapeutic target for advanced prostate cancer. Recently, both the promoter and the enhancer driving prostate-specific expression of the PSMA gene were cloned. We describe here our analysis of the PSMA enhancer for the most active region(s) and present a way of using the enhancer in combination with the E. coli cytosine deaminase gene for suicide-driven gene therapy that converts the nontoxic prodrug 5-fluorocytosine (5-FC) into the cytotoxic drug 5-fluorouracil (5-FU) in prostate cancer cells. METHODS Deletion constructs of the full-length PSMA enhancer were subcloned into a luciferase reporter vector containing either the PSMA or SV-40 promoter. The most active portion of the enhancer was then determined via luciferase activity in the C4-2 cell line. We then replaced the luciferase gene with the E. coli cytosine deaminase gene in the subclone that showed the most luciferase activity. The specificity of this technique was examined in vitro, using the prostate cancer cell line LNCaP, its androgen-independent derivative C4-2, and a number of nonprostatic cell lines. The toxicity of 5-FC and 5-FU on transiently transfected cell lines was then compared. RESULTS The enhancer region originally isolated from the PSMA gene was approximately 2 kb. Deletion constructs revealed that at least two distinct regions seem to contribute to expression of the gene in prostate cancer cells, and therefore the best construct for prostate-specific expression was determined to be 1, 648 bp long. The IC(50) of 5-FC was similar in all cell lines tested (>10 mM). However, transfection with the 1648 nt PSMA enhancer and the PSMA promoter to drive the cytosine deaminase gene enhanced toxicity in a dose-dependent manner more than 50-fold, while cells that did not express the PSMA gene were not significantly sensitized by transfection. CONCLUSIONS Suicide gene therapy using the PSMA enhancer may be of benefit to patients who have undergone androgen ablation therapy and are suffering a relapse of disease.
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Affiliation(s)
- D S O'Keefe
- George M. O'Brien Urology Research Center, Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA
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Millar DS, Paul CL, Molloy PL, Clark SJ. A distinct sequence (ATAAA)n separates methylated and unmethylated domains at the 5'-end of the GSTP1 CpG island. J Biol Chem 2000; 275:24893-9. [PMID: 10779522 DOI: 10.1074/jbc.m906538199] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
What defines the boundaries between methylated and unmethylated domains in the genome is unclear. In this study we used bisulfite genomic sequencing to map the boundaries of methylation that flank the 5'- and 3'-ends of the CpG island spanning the promoter region of the glutathione S-transferase (GSTP1) gene. We show that GSTP1 is expressed in a wide range of tissues including brain, lung, skeletal muscle, spleen, pancreas, bone marrow, prostate, heart, and blood and that this expression is associated with the CpG island being unmethylated. In these normal tissues a marked boundary was found to separate the methylated and unmethylated regions of the gene at the 5'-flank of the CpG island, and this boundary correlated with an (ATAAA)(19-24) repeated sequence. In contrast, the 3'-end of the CpG island was not marked by a sharp transition in methylation but by a gradual change in methylation density over about 500 base pairs. In normal tissue the sequences on either side of the 5'-boundary appear to lie in separate domains in which CpG methylation is independently controlled. These separate methylation domains are lost in all prostate cancer where GSTP1 expression is silenced and methylation extends throughout the island and spans across both the 5'- and 3'-boundary regions.
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Affiliation(s)
- D S Millar
- Kanematsu Laboratories, Royal Prince Alfred Hospital, Missenden Road, Camperdown, New South Wales 2050, Australia
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Messina M, Yu DM, Learoyd DL, Both GW, Molloy PL, Robinson BG. High level, tissue-specific expression of a modified calcitonin/calcitonin gene-related peptide promoter in a human medullary thyroid carcinoma cell line. Mol Cell Endocrinol 2000; 164:219-24. [PMID: 11026573 DOI: 10.1016/s0303-7207(00)00204-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The efficient and high level expression of therapeutic genes in target cells is critical for effective gene therapy. We have developed a novel promoter by utilizing tandem repeats of a tissue-specific regulatory element from the calcitonin/calcitonin gene-related peptide (CT/CGRP) gene placed in close proximity to a basal promoter, thereby removing interstitial sequences. This promoter drives expression of reporter genes at much higher levels than the natural promoter while significantly improving specificity in thyroid C cells.
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Affiliation(s)
- M Messina
- Department of Cancer Genetics, Kolling Institute of Medical Research, Royal North Shore Hospital, St. Leonards, NSW, Australia
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Affiliation(s)
- P L Molloy
- CSIRO Molecular Science, Sydney, Australia
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47
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Millar DS, Ow KK, Paul CL, Russell PJ, Molloy PL, Clark SJ. Detailed methylation analysis of the glutathione S-transferase pi (GSTP1) gene in prostate cancer. Oncogene 1999; 18:1313-24. [PMID: 10022813 DOI: 10.1038/sj.onc.1202415] [Citation(s) in RCA: 169] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Glutathione-S-Transferases (GSTs) comprise a family of isoenzymes that provide protection to mammalian cells against electrophilic metabolites of carcinogens and reactive oxygen species. Previous studies have shown that the CpG-rich promoter region of the pi-class gene GSTP1 is methylated at single restriction sites in the majority of prostate cancers. In order to understand the nature of abnormal methylation of the GSTP1 gene in prostate cancer we undertook a detailed analysis of methylation at 131 CpG sites spanning the promoter and body of the gene. Our results show that DNA methylation is not confined to specific CpG sites in the promoter region of the GSTP1 gene but is extensive throughout the CpG island in prostate cancer cells. Furthermore we found that both alleles are abnormally methylated in this region. In normal prostate tissue, the entire CpG island was unmethylated, but extensive methylation was found outside the island in the body of the gene. Loss of GSTP1 expression correlated with DNA methylation of the CpG island in both prostate cancer cell lines and cancer tissues whereas methylation outside the CpG island in normal prostate tissue appeared to have no effect on gene expression.
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Affiliation(s)
- D S Millar
- Kanematsu Laboratories, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
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O'Keefe DS, Su SL, Bacich DJ, Horiguchi Y, Luo Y, Powell CT, Zandvliet D, Russell PJ, Molloy PL, Nowak NJ, Shows TB, Mullins C, Vonder Haar RA, Fair WR, Heston WD. Mapping, genomic organization and promoter analysis of the human prostate-specific membrane antigen gene. Biochim Biophys Acta 1998; 1443:113-27. [PMID: 9838072 DOI: 10.1016/s0167-4781(98)00200-0] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Prostate-specific membrane antigen (PSMA) is a 100 kDa type II transmembrane protein with folate hydrolase and NAALAdase activity. PSMA is highly expressed in prostate cancer and the vasculature of most solid tumors, and is currently the target of a number of diagnostic and therapeutic strategies. PSMA is also expressed in the brain, and is involved in conversion of the major neurotransmitter NAAG (N-acetyl-aspartyl glutamate) to NAA and free glutamate, the levels of which are disrupted in several neurological disorders including multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease and schizophrenia. To facilitate analysis of the role of PSMA in carcinoma we have determined the structural organization of the gene. The gene consists of 19 exons spanning approximately 60 kb of genomic DNA. A 1244 nt portion of the 5' region of the PSMA gene was able to drive the firefly luciferase reporter gene in prostate but not breast-derived cell lines. We have mapped the gene encoding PSMA to 11p11-p12, however a gene homologous, but not identical, to PSMA exists on chromosome 11q14. Analysis of sequence differences between non-coding regions of the two genes suggests duplication and divergence occurred 22 million years ago.
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Affiliation(s)
- D S O'Keefe
- Urologic Oncology Research Laboratory, Molecular Pharmacology and Therapeutics Division, Sloan-Kettering Institute for Cancer Research, Box 334, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York, NY 10021, USA
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Martiniello-Wilks R, Garcia-Aragon J, Daja MM, Russell P, Both GW, Molloy PL, Lockett LJ, Russell PJ. In vivo gene therapy for prostate cancer: preclinical evaluation of two different enzyme-directed prodrug therapy systems delivered by identical adenovirus vectors. Hum Gene Ther 1998; 9:1617-26. [PMID: 9694160 DOI: 10.1089/hum.1998.9.11-1617] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Advanced prostate cancer is invariably lethal once it becomes androgen independent (AI). With the aim of developing a new treatment we have used the human androgen-independent prostate cancer cell line, PC-3, to evaluate the effectiveness of two enzyme-directed prodrug therapy (EPT) systems as a novel means for promoting tumor cell destruction in vivo. We have confined our study to the use of a PSA promoter, in a preliminary attempt to achieve prostate specificity. The two EPT systems used were the HSVTK/GCV and PNP/6MPDR systems. These were chosen for their differential dependence on DNA replication for their mechanism of action. In the present work, either the HSVTK or PNP gene, each controlled by a PSA promoter fragment, was delivered by an E1-, replication-deficient human adenovirus (Ad5) into PC-3 tumors growing subcutaneously in BALB/c nude mice. Tumors were injected with a single dose of recombinant Ad5 and mice were treated intraperitoneally with the appropriate prodrug, twice daily, for 6 days thereafter. The growth of established PC-3 tumors was significantly suppressed and host survival increased with a single course of HSVTK/GCV or PNP/6MPDR treatment. HSVTK/GCV-treated PC-3 tumor growth was 80% less than that of control treatments on day 33, while PNP/6MPDR-treated tumor growth was approximately 75% less than that of control treatments on day 52. Survival data showed that 20% of HSVTK/GCV- or PNP/6MPDR-treated animals lived >45 and >448 days, respectively, longer than control animals. These results demonstrate that both HSVTK/GCV and PNP/6MPDR therapies interrupt the growth of an aggressive human prostate cancer cell line in vivo.
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Affiliation(s)
- R Martiniello-Wilks
- Oncology Research Centre, Prince of Wales Hospital, Randwick, NSW, Australia
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50
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Abstract
BACKGROUND To evaluate their relative activity and specificity for prostate cells promoter and regulatory regions from three prostate-expressed genes-prostate-specific antigen (PSA), probasin, and relaxin H2-have been compared in prostate cell lines and in lines of breast, bladder, liver, kidney, lung, and ovarian origin. METHODS After transfection into different cell types, the activity of promoters was assayed using linked reporter genes and normalized against that of the Rous sarcoma virus. Activity was measured both in the presence and in the absence of co-transfected androgen receptor (AR). RESULTS PSA and probasin regulatory regions showed strong responsiveness to co-transfection of the AR in most cell types. The core PSA promoter region showed low activity and specificity, but the specificity and level of expression were substantially increased by inclusion of upstream sequences, particularly the enhancer region. Probasin promoter fragments showed specificity of expression for prostate cell lines but required AR for significant levels of expression. Relaxin promoter fragments directed significant AR-inducible expression in prostate cells but showed little specificity and variable AR responsiveness in other cell types. CONCLUSIONS Of regulatory regions tested, a 430-base pair probasin promoter and PSA enhancer/core promoter showed the best combination of AR-stimulated prostate cell expression with limited expression in other cell types.
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Affiliation(s)
- D E Brookes
- CSIRO Division of Molecular Science, New South Wales, Australia
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