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Daenekas B, Pérez E, Boniolo F, Stefan S, Benfatto S, Sill M, Sturm D, Jones DTW, Capper D, Zapatka M, Hovestadt V. Conumee 2.0: enhanced copy-number variation analysis from DNA methylation arrays for humans and mice. Bioinformatics 2024; 40:btae029. [PMID: 38244574 PMCID: PMC10868300 DOI: 10.1093/bioinformatics/btae029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 12/14/2023] [Accepted: 01/16/2024] [Indexed: 01/22/2024] Open
Abstract
MOTIVATION Copy-number variations (CNVs) are common genetic alterations in cancer and their detection may impact tumor classification and therapeutic decisions. However, detection of clinically relevant large and focal CNVs remains challenging when sample material or resources are limited. This has motivated us to create a software tool to infer CNVs from DNA methylation arrays which are often generated as part of clinical routines and in research settings. RESULTS We present our R package, conumee 2.0, that combines tangent normalization, an adjustable genomic binning heuristic, and weighted circular binary segmentation to utilize DNA methylation arrays for CNV analysis and mitigate technical biases and batch effects. Segmentation results were validated in a lung squamous cell carcinoma dataset from TCGA (n = 367 samples) by comparison to segmentations derived from genotyping arrays (Pearson's correlation coefficient of 0.91). We further introduce a segmented block bootstrapping approach to detect focal alternations that achieved 60.9% sensitivity and 98.6% specificity for deletions affecting CDKN2A/B (60.0% and 96.9% for RB1, respectively) in a low-grade glioma cohort from TCGA (n = 239 samples). Finally, our tool provides functionality to detect and summarize CNVs across large sample cohorts. AVAILABILITY AND IMPLEMENTATION Conumee 2.0 is available under open-source license at: https://github.com/hovestadtlab/conumee2.
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Affiliation(s)
- Bjarne Daenekas
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, United States
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, United States
- Department of Neuropathology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Eilís Pérez
- Department of Neuropathology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Fabio Boniolo
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, United States
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, United States
| | - Sabina Stefan
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, United States
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, United States
| | - Salvatore Benfatto
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, United States
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, United States
| | - Martin Sill
- Hopp Children’s Cancer Center Heidelberg (KiTZ), 69120 Heidelberg, Germany
- Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
| | - Dominik Sturm
- Hopp Children’s Cancer Center Heidelberg (KiTZ), 69120 Heidelberg, Germany
- Division of Pediatric Glioma Research, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
- Department of Pediatric Oncology, Hematology & Immunology, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - David T W Jones
- Hopp Children’s Cancer Center Heidelberg (KiTZ), 69120 Heidelberg, Germany
- Division of Pediatric Glioma Research, German Cancer Research Center (DKFZ) and German Cancer Consortium (DKTK), 69120 Heidelberg, Germany
| | - David Capper
- Department of Neuropathology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
- German Cancer Consortium (DKTK), Partner Site Berlin, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Marc Zapatka
- Division of Molecular Genetics, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Volker Hovestadt
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, United States
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, United States
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Cox DRA, McClure T, Zhang F, Wong BKL, Testro A, Goh SK, Muralidharan V, Dobrovic A. Graft-Derived Cell-Free DNA Quantification following Liver Transplantation Using Tissue-Specific DNA Methylation and Donor-Specific Genotyping Techniques: An Orthogonal Comparison Study. EPIGENOMES 2023; 7:11. [PMID: 37367181 DOI: 10.3390/epigenomes7020011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 05/07/2023] [Accepted: 05/30/2023] [Indexed: 06/28/2023] Open
Abstract
Background: Graft-derived cell-free DNA (gdcfDNA) analysis has shown promise as a non-invasive tool for monitoring organ health following solid organ transplantation. A number of gdcfDNA analysis techniques have been described; however, the majority rely on sequencing or prior genotyping to detect donor-recipient mis-matched genetic polymorphisms. Differentially methylated regions of DNA can be used to identify the tissue-of-origin of cell-free DNA (cfDNA) fragments. In this study, we aimed to directly compare the performance of gdcfDNA monitoring using graft-specific DNA methylation analysis and donor-recipient genotyping techniques in a pilot cohort of clinical samples from patients post-liver transplantation. Results: 7 patients were recruited prior to LT, 3 developed early, biopsy-proven TCMR in the first 6 weeks post-LT. gdcfDNA was successfully quantified in all samples using both approaches. There was a high level of technical correlation between results using the two techniques (Spearman testing, rs = 0.87, p < 0.0001). gdcfDNA levels quantified using the genotyping approach were significantly greater across all timepoints in comparison to the tissue-specific DNA methylation-based approach: e.g., day 1 post-LT median 31,350 copies/mL (IQR 6731-64,058) vs. 4133 copies/mL (IQR 1100-8422), respectively. Qualitative trends in gdcfDNA levels for each patient were concordant between the two assays. Acute TCMR was preceded by significant elevations in gdcfDNA as quantified by both techniques. Elevations in gdcfDNA, using both techniques, were suggestive of TCMR in this pilot study with a 6- and 3-day lead-time prior to histological diagnosis in patients 1 and 2. Conclusions: Both the graft-specific methylation and genotyping techniques successfully quantified gdcfDNA in patients post-LT with statistically significant concordance. A direct comparison of these two techniques is not only important from a technical perspective for orthogonal validation, but significantly adds weight to the evidence that gdcfDNA monitoring reflects the underlying biology. Both techniques identified LT recipients who developed acute TCMR, with several days lead-time in comparison to conventional diagnostic workflows. Whilst the two assays performed comparably, gdcfDNA monitoring based on graft-specific DNA methylation patterns in cfDNA offers major practical advantages over the donor-recipient genotyping, and hence enhances the potential to translate this emerging technology into clinical practice.
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Affiliation(s)
- Daniel R A Cox
- Department of Surgery (Austin Precinct), University of Melbourne, Melbourne, VIC 3084, Australia
- HPB & Liver Transplant Surgery Unit, Department of Surgery, Austin Health, Melbourne, VIC 3084, Australia
- BEACON Biomarkers Laboratory, University of Melbourne, Melbourne, VIC 3084, Australia
| | - Tess McClure
- Department of Surgery (Austin Precinct), University of Melbourne, Melbourne, VIC 3084, Australia
- BEACON Biomarkers Laboratory, University of Melbourne, Melbourne, VIC 3084, Australia
- Liver Transplant Unit, Department of Gastroenterology & Hepatology, Austin Health, Melbourne, VIC 3084, Australia
| | - Fan Zhang
- BEACON Biomarkers Laboratory, University of Melbourne, Melbourne, VIC 3084, Australia
| | - Boris Ka Leong Wong
- BEACON Biomarkers Laboratory, University of Melbourne, Melbourne, VIC 3084, Australia
- School of Cancer Medicine, La Trobe University, Melbourne, VIC 3084, Australia
| | - Adam Testro
- Liver Transplant Unit, Department of Gastroenterology & Hepatology, Austin Health, Melbourne, VIC 3084, Australia
| | - Su Kah Goh
- Department of Surgery (Austin Precinct), University of Melbourne, Melbourne, VIC 3084, Australia
| | - Vijayaragavan Muralidharan
- Department of Surgery (Austin Precinct), University of Melbourne, Melbourne, VIC 3084, Australia
- HPB & Liver Transplant Surgery Unit, Department of Surgery, Austin Health, Melbourne, VIC 3084, Australia
- BEACON Biomarkers Laboratory, University of Melbourne, Melbourne, VIC 3084, Australia
| | - Alexander Dobrovic
- Department of Surgery (Austin Precinct), University of Melbourne, Melbourne, VIC 3084, Australia
- BEACON Biomarkers Laboratory, University of Melbourne, Melbourne, VIC 3084, Australia
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Shang L, Zhao W, Wang YZ, Li Z, Choi JJ, Kho M, Mosley TH, Kardia SLR, Smith JA, Zhou X. meQTL mapping in the GENOA study reveals genetic determinants of DNA methylation in African Americans. Nat Commun 2023; 14:2711. [PMID: 37169753 PMCID: PMC10175543 DOI: 10.1038/s41467-023-37961-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 04/07/2023] [Indexed: 05/13/2023] Open
Abstract
Identifying genetic variants that are associated with variation in DNA methylation, an analysis commonly referred to as methylation quantitative trait locus (meQTL) mapping, is an important first step towards understanding the genetic architecture underlying epigenetic variation. Most existing meQTL mapping studies have focused on individuals of European ancestry and are underrepresented in other populations, with a particular absence of large studies in populations with African ancestry. We fill this critical knowledge gap by performing a large-scale cis-meQTL mapping study in 961 African Americans from the Genetic Epidemiology Network of Arteriopathy (GENOA) study. We identify a total of 4,565,687 cis-acting meQTLs in 320,965 meCpGs. We find that 45% of meCpGs harbor multiple independent meQTLs, suggesting potential polygenic genetic architecture underlying methylation variation. A large percentage of the cis-meQTLs also colocalize with cis-expression QTLs (eQTLs) in the same population. Importantly, the identified cis-meQTLs explain a substantial proportion (median = 24.6%) of methylation variation. In addition, the cis-meQTL associated CpG sites mediate a substantial proportion (median = 24.9%) of SNP effects underlying gene expression. Overall, our results represent an important step toward revealing the co-regulation of methylation and gene expression, facilitating the functional interpretation of epigenetic and gene regulation underlying common diseases in African Americans.
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Affiliation(s)
- Lulu Shang
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Wei Zhao
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Yi Zhe Wang
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Zheng Li
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jerome J Choi
- Population Health Sciences, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, 53726, USA
| | - Minjung Kho
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Thomas H Mosley
- Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS, 39126, USA
| | - Sharon L R Kardia
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jennifer A Smith
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, 48109, USA.
| | - Xiang Zhou
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI, 48109, USA.
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Tost J. Current and Emerging Technologies for the Analysis of the Genome-Wide and Locus-Specific DNA Methylation Patterns. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:395-469. [DOI: 10.1007/978-3-031-11454-0_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Shanthikumar S, Neeland MR, Saffery R, Ranganathan SC, Oshlack A, Maksimovic J. DNA Methylation Profiles of Purified Cell Types in Bronchoalveolar Lavage: Applications for Mixed Cell Paediatric Pulmonary Studies. Front Immunol 2021; 12:788705. [PMID: 35003108 PMCID: PMC8727592 DOI: 10.3389/fimmu.2021.788705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 12/03/2021] [Indexed: 01/15/2023] Open
Abstract
In epigenome-wide association studies analysing DNA methylation from samples containing multiple cell types, it is essential to adjust the analysis for cell type composition. One well established strategy for achieving this is reference-based cell type deconvolution, which relies on knowledge of the DNA methylation profiles of purified constituent cell types. These are then used to estimate the cell type proportions of each sample, which can then be incorporated to adjust the association analysis. Bronchoalveolar lavage is commonly used to sample the lung in clinical practice and contains a mixture of different cell types that can vary in proportion across samples, affecting the overall methylation profile. A current barrier to the use of bronchoalveolar lavage in DNA methylation-based research is the lack of reference DNA methylation profiles for each of the constituent cell types, thus making reference-based cell composition estimation difficult. Herein, we use bronchoalveolar lavage samples collected from children with cystic fibrosis to define DNA methylation profiles for the four most common and clinically relevant cell types: alveolar macrophages, granulocytes, lymphocytes and alveolar epithelial cells. We then demonstrate the use of these methylation profiles in conjunction with an established reference-based methylation deconvolution method to estimate the cell type composition of two different tissue types; a publicly available dataset derived from artificial blood-based cell mixtures and further bronchoalveolar lavage samples. The reference DNA methylation profiles developed in this work can be used for future reference-based cell type composition estimation of bronchoalveolar lavage. This will facilitate the use of this tissue in studies examining the role of DNA methylation in lung health and disease.
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Affiliation(s)
- Shivanthan Shanthikumar
- Respiratory and Sleep Medicine, Royal Children’s Hospital, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Respiratory Diseases, Murdoch Children’s Research Institute, Parkville, VIC, Australia
- *Correspondence: Shivanthan Shanthikumar,
| | - Melanie R. Neeland
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Molecular Immunity, Murdoch Children’s Research Institute, Parkville, VIC, Australia
| | - Richard Saffery
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Molecular Immunity, Murdoch Children’s Research Institute, Parkville, VIC, Australia
| | - Sarath C. Ranganathan
- Respiratory and Sleep Medicine, Royal Children’s Hospital, Parkville, VIC, Australia
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Respiratory Diseases, Murdoch Children’s Research Institute, Parkville, VIC, Australia
| | - Alicia Oshlack
- Computational Biology Program, Peter MacCallum Cancer Centre, Parkville, VIC, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, VIC, Australia
- School of BioScience, University of Melbourne, Parkville, VIC, Australia
| | - Jovana Maksimovic
- Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
- Respiratory Diseases, Murdoch Children’s Research Institute, Parkville, VIC, Australia
- Computational Biology Program, Peter MacCallum Cancer Centre, Parkville, VIC, Australia
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Kerachian MA, Azghandi M, Mozaffari-Jovin S, Thierry AR. Guidelines for pre-analytical conditions for assessing the methylation of circulating cell-free DNA. Clin Epigenetics 2021; 13:193. [PMID: 34663458 PMCID: PMC8525023 DOI: 10.1186/s13148-021-01182-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/04/2021] [Indexed: 02/06/2023] Open
Abstract
Methylation analysis of circulating cell-free DNA (cirDNA), as a liquid biopsy, has a significant potential to advance the detection, prognosis, and treatment of cancer, as well as many genetic disorders. The role of epigenetics in disease development has been reported in several hereditary disorders, and epigenetic modifications are regarded as one of the earliest and most significant genomic aberrations that arise during carcinogenesis. Liquid biopsy can be employed for the detection of these epigenetic biomarkers. It consists of isolation (pre-analytical) and detection (analytical) phases. The choice of pre-analytical variables comprising cirDNA extraction and bisulfite conversion methods can affect the identification of cirDNA methylation. Indeed, different techniques give a different return of cirDNA, which confirms the importance of pre-analytical procedures in clinical diagnostics. Although novel techniques have been developed for the simplification of methylation analysis, the process remains complex, as the steps of DNA extraction, bisulfite treatment, and methylation detection are each carried out separately. Recent studies have noted the absence of any standard method for the pre-analytical processing of methylated cirDNA. We have therefore conducted a comprehensive and systematic review of the important pre-analytical and analytical variables and the patient-related factors which form the basis of our guidelines for analyzing methylated cirDNA in liquid biopsy.
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Affiliation(s)
- Mohammad Amin Kerachian
- Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
- Cancer Genetics Research Unit, Reza Radiotherapy and Oncology Center, Mashhad, Iran.
| | - Marjan Azghandi
- Cancer Genetics Research Unit, Reza Radiotherapy and Oncology Center, Mashhad, Iran
- Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Sina Mozaffari-Jovin
- Medical Genetics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Alain R Thierry
- IRCM, Institute of Research in Oncology of Montpellier, Montpellier, France.
- INSERM, U1194, Montpellier, France.
- University of Montpellier, Montpellier, France.
- ICM, Regional Institute of Cancer of Montpellier, Montpellier, France.
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Yu H, Bai L, Tang G, Wang X, Huang M, Cao G, Wang J, Luo Y. Novel Assay for Quantitative Analysis of DNA Methylation at Single-Base Resolution. Clin Chem 2019; 65:664-673. [PMID: 30737203 DOI: 10.1373/clinchem.2018.298570] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 01/22/2019] [Indexed: 12/14/2022]
Abstract
BACKGROUND The DNA methylation profile provides valuable biological information with potential clinical utility. Several methods, such as quantitative methylation-specific PCR (qMSP), have been developed to examine methylation of specific CpG sites. Existing qMSP-based techniques fail to examine the genomic methylation at a single-base resolution, particularly for loci in gene bodies or extensive CpG open seas lacking flanking CpGs. Therefore, we established a novel assay for quantitative analysis of single-base methylation. METHODS To achieve a robust single-base specificity, we developed a PCR-based method using paired probes following bisulfite treatment. The 6-carboxyfluorescein- and 2'-chloro-7'phenyl-1,4-dichloro-6-carboxy-fluorescein-labeled probes conjugated with minor groove binder were designed to specifically bind to the methylated and unmethylated allele of targeted single CpGs at their 3' half regions, respectively. The methylation percentage was calculated by values of methylation / (methylation + unmethylation). RESULTS In the detection of single CpGs within promoters or bodies of 4 human genes, the quantitative analysis of the single-base methylation assay showed a detection capability in the 1 to 1:10000 dilution experiments with linearity over 4 orders of magnitude (R 2 = 0.989-0.994; all P < 0.001). In a cohort of 10 colorectal cancer samples, the assay showed a comparable detection performance with bisulfite pyrosequencing (R 2 = 0.875-0.990; all P < 0.001), which was better than conventional qMSP methods normalized by input control reaction (R 2 = 0.841 vs 0.769; P = 0.002 vs 0.009). CONCLUSIONS This assay is highly specific and sensitive for determining single-base methylation and, thus, is potentially useful for methylation-based panels in diagnostic and prognostic applications.
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Affiliation(s)
- Huichuan Yu
- Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Disease, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Liangliang Bai
- Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Disease, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Guannan Tang
- Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Disease, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xiaolin Wang
- Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Disease, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Meijin Huang
- Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Guangwen Cao
- Department of Epidemiology, Second Military Medical University, Shanghai, China
| | - Jianping Wang
- Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Disease, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China.,Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yanxin Luo
- Guangdong Institute of Gastroenterology, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Disease, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China; .,Department of Colorectal Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
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8
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Zavridou M, Mastoraki S, Strati A, Tzanikou E, Chimonidou M, Lianidou E. Evaluation of Preanalytical Conditions and Implementation of Quality Control Steps for Reliable Gene Expression and DNA Methylation Analyses in Liquid Biopsies. Clin Chem 2018; 64:1522-1533. [DOI: 10.1373/clinchem.2018.292318] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 06/28/2018] [Indexed: 01/09/2023]
Abstract
Abstract
BACKGROUND
Liquid biopsy provides important information for the prognosis and treatment of cancer patients. In this study, we evaluated the effects of preanalytical conditions on gene expression and DNA methylation analyses in liquid biopsies.
METHODS
We tested the stability of circulating tumor cell (CTC) messenger RNA by spiking MCF-7 cells in healthy donor peripheral blood (PB) drawn into 6 collection-tube types with various storage conditions. CTCs were enriched based on epithelial cell adhesion molecule positivity, and RNA was isolated followed by cDNA synthesis. Gene expression was quantified using RT-quantitative PCR for CK19 and B2M. We evaluated the stability of DNA methylation in plasma under different storage conditions by spiking DNA isolated from MCF-7 cells in healthy donor plasma. Two commercially available sodium bisulfite (SB)-conversion kits were compared, in combination with whole genome amplification (WGA), to evaluate the stability of SB-converted DNA. SB-converted DNA samples were analyzed by real-time methylation-specific PCR (MSP) for ACTB, SOX17, and BRMS1. Quality control was assessed using Levey–Jennings graphs.
RESULTS
RNA-based analysis in CTCs is severely impeded by the preservatives used in many PB collection tubes (except for EDTA), as well as by time to analysis. Plasma and SB-converted DNA samples are stable and can be used safely for MSP when kept at −80 °C. Downstream WGA of SB-converted DNA compensated for the limited amount of available sample in liquid biopsies.
CONCLUSIONS
Standardization of preanalytical conditions and implementation of quality control steps is extremely important for reliable liquid biopsy analysis, and a prerequisite for routine applications in the clinic.
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Affiliation(s)
- Martha Zavridou
- Analysis of Circulating Tumor Cells, Lab of Analytical Chemistry, Department of Chemistry, University of Athens, Athens, Greece
| | - Sofia Mastoraki
- Analysis of Circulating Tumor Cells, Lab of Analytical Chemistry, Department of Chemistry, University of Athens, Athens, Greece
| | - Areti Strati
- Analysis of Circulating Tumor Cells, Lab of Analytical Chemistry, Department of Chemistry, University of Athens, Athens, Greece
| | - Eleni Tzanikou
- Analysis of Circulating Tumor Cells, Lab of Analytical Chemistry, Department of Chemistry, University of Athens, Athens, Greece
| | - Maria Chimonidou
- Analysis of Circulating Tumor Cells, Lab of Analytical Chemistry, Department of Chemistry, University of Athens, Athens, Greece
| | - Evi Lianidou
- Analysis of Circulating Tumor Cells, Lab of Analytical Chemistry, Department of Chemistry, University of Athens, Athens, Greece
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9
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Nunes SP, Moreira-Barbosa C, Salta S, Palma de Sousa S, Pousa I, Oliveira J, Soares M, Rego L, Dias T, Rodrigues J, Antunes L, Henrique R, Jerónimo C. Cell-Free DNA Methylation of Selected Genes Allows for Early Detection of the Major Cancers in Women. Cancers (Basel) 2018; 10:cancers10100357. [PMID: 30261643 PMCID: PMC6210550 DOI: 10.3390/cancers10100357] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 09/21/2018] [Accepted: 09/25/2018] [Indexed: 02/06/2023] Open
Abstract
Background: Breast (BrC), colorectal (CRC) and lung (LC) cancers are the three most common and deadly cancers in women. Cancer screening entails an increase in early stage disease detection but is hampered by high false-positive rates and overdiagnosis/overtreatment. Aberrant DNA methylation occurs early in cancer and may be detected in circulating cell-free DNA (ccfDNA), constituting a valuable biomarker and enabling non-invasive testing for cancer detection. We aimed to develop a ccfDNA methylation-based test for simultaneous detection of BrC, CRC and LC. Methods: CcfDNA from BrC, CRC and LC patients and asymptomatic controls were extracted from plasma, sodium-bisulfite modified and whole-genome amplified. APC, FOXA1, MGMT, RARβ2, RASSF1A, SCGB3A1, SEPT9, SHOX2 and SOX17 promoter methylation levels were determined by multiplex quantitative methylation-specific PCR. Associations between methylation and standard clinicopathological parameters were assessed. Biomarkers’ diagnostic performance was also evaluated. Results: A “PanCancer” panel (APC, FOXA1, RASSF1A) detected the three major cancers with 72% sensitivity and 74% specificity, whereas a “CancerType” panel (SCGB3A1, SEPT9 and SOX17) indicated the most likely cancer topography, with over 80% specificity, although with limited sensitivity. Conclusions: CcfDNA’s methylation assessment allows for simultaneous screening of BrC, CRC and LC, complementing current modalities, perfecting cancer suspects’ triage, increasing compliance and cost-effectiveness.
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Affiliation(s)
- Sandra P Nunes
- Cancer Biology & Epigenetics Group-Research Center, Portuguese Oncology Institute of Porto (CI-IPOP), 4200-072 Porto, Portugal.
- Master in Oncology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), 4050-313 Porto, Portugal.
| | - Catarina Moreira-Barbosa
- Cancer Biology & Epigenetics Group-Research Center, Portuguese Oncology Institute of Porto (CI-IPOP), 4200-072 Porto, Portugal.
| | - Sofia Salta
- Cancer Biology & Epigenetics Group-Research Center, Portuguese Oncology Institute of Porto (CI-IPOP), 4200-072 Porto, Portugal.
| | - Susana Palma de Sousa
- Breast Cancer Clinic and Department of Medical Oncology, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal.
| | - Inês Pousa
- Lung Cancer Clinic and Department of Medical Oncology, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal.
| | - Júlio Oliveira
- Lung Cancer Clinic and Department of Medical Oncology, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal.
| | - Marta Soares
- Lung Cancer Clinic and Department of Medical Oncology, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal.
| | - Licínio Rego
- Digestive Tract Pathology Clinic and Surgical Oncology, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal.
| | - Teresa Dias
- Digestive Tract Pathology Clinic and Surgical Oncology, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal.
| | - Jéssica Rodrigues
- Department of Epidemiology, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal.
| | - Luís Antunes
- Department of Epidemiology, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal.
| | - Rui Henrique
- Cancer Biology & Epigenetics Group-Research Center, Portuguese Oncology Institute of Porto (CI-IPOP), 4200-072 Porto, Portugal.
- Department of Pathology, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal.
- Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), 4050-313 Porto, Portugal.
| | - Carmen Jerónimo
- Cancer Biology & Epigenetics Group-Research Center, Portuguese Oncology Institute of Porto (CI-IPOP), 4200-072 Porto, Portugal.
- Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar, University of Porto (ICBAS-UP), 4050-313 Porto, Portugal.
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10
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Wipfler K, Cornish AS, Guda C. Comparative molecular characterization of typical and exceptional responders in glioblastoma. Oncotarget 2018; 9:28421-28433. [PMID: 29983870 PMCID: PMC6033343 DOI: 10.18632/oncotarget.25420] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 04/27/2018] [Indexed: 12/21/2022] Open
Abstract
Glioblastoma (GBM) is the most common and the deadliest type of primary brain tumor, with a median survival time of only 15 months despite aggressive treatment. Although most patients have an extremely poor prognosis, a relatively small number of patients survive far beyond the median survival time. Investigation of these exceptional responders has sparked a great deal of interest and is becoming an important focus in the field of cancer research. To investigate the molecular differences between typical and exceptional responders in GBM, comparative analyses of somatic mutations, copy number, methylation, and gene expression datasets from The Cancer Genome Atlas were performed, and the results of these analyses were integrated via gene ontology and pathway analyses to assess the functional significance of the differential aberrations. Less severe copy number loss of CDKN2A, lower expression of CXCL8, and FLG mutations are all associated with an exceptional response. Typical responders are characterized by upregulation of NF-κB signaling and of pro-inflammatory cytokines, while exceptional responders are characterized by upregulation of Alzheimer's and Parkinson's disease pathways as well as of genes involved in synaptic transmission. The upregulated pathways and processes in typical responders are consistently associated with more aggressive tumor phenotypes, while those in the exceptional responders suggest a retained ability in tumor cells to undergo cell death in response to treatment. With the upcoming launch of the National Cancer Institute's Exceptional Responders Initiative, similar studies with much larger sample sizes will likely become possible, hopefully providing even more insight into the molecular differences between typical and exceptional responders.
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Affiliation(s)
- Kristin Wipfler
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Adam S. Cornish
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Chittibabu Guda
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Bioinformatics and Systems Biology Core, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
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11
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Groen K, Lea RA, Maltby VE, Scott RJ, Lechner-Scott J. Letter to the editor: blood processing and sample storage have negligible effects on methylation. Clin Epigenetics 2018; 10:22. [PMID: 29456766 PMCID: PMC5813389 DOI: 10.1186/s13148-018-0455-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 02/06/2018] [Indexed: 11/10/2022] Open
Abstract
DNA methylation is a dynamic epigenetic mechanism. Researchers aiming to assess archived DNA samples are expressing concern about the effect of technical factors on methylation, as this may confound results. We reviewed recent reports examining this issue in blood samples and concluded that variation in collection, storage, and processing of blood DNA confers negligible effects on both global methylation and methylation status of specific genes. These results are concordant with studies that have investigated the effect of sample storage and processing on methylation in other tissues, such as tumour, sperm, and placenta samples.
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Affiliation(s)
- Kira Groen
- 1School of Medicine and Public Health, University of Newcastle, Callaghan, NSW 2308 Australia.,2Centre for Information Based Medicine, Hunter Medical Research Institute, New Lambton Heights, NSW 2305 Australia
| | - Rodney A Lea
- 2Centre for Information Based Medicine, Hunter Medical Research Institute, New Lambton Heights, NSW 2305 Australia.,3Institute of Health and Biomedical Innovations, School of Biomedical Science, Queensland University of Technology, Kelvin Grove, QLD 4059 Australia
| | - Vicki E Maltby
- 1School of Medicine and Public Health, University of Newcastle, Callaghan, NSW 2308 Australia.,2Centre for Information Based Medicine, Hunter Medical Research Institute, New Lambton Heights, NSW 2305 Australia
| | - Rodney J Scott
- 2Centre for Information Based Medicine, Hunter Medical Research Institute, New Lambton Heights, NSW 2305 Australia.,4School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW 2308 Australia.,5Division of Molecular Genetics, Pathology North, John Hunter Hospital, New Lambton Heights, NSW 2305 Australia
| | - Jeannette Lechner-Scott
- 1School of Medicine and Public Health, University of Newcastle, Callaghan, NSW 2308 Australia.,2Centre for Information Based Medicine, Hunter Medical Research Institute, New Lambton Heights, NSW 2305 Australia.,6Department of Neurology, John Hunter Hospital, New Lambton Heights, NSW 2305 Australia
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12
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Crime investigation through DNA methylation analysis: methods and applications in forensics. EGYPTIAN JOURNAL OF FORENSIC SCIENCES 2018. [DOI: 10.1186/s41935-018-0042-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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13
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Ghantous A, Hernandez-Vargas H, Herceg Z. DNA Methylation Analysis from Blood Spots: Increasing Yield and Quality for Genome-Wide and Locus-Specific Methylation Analysis. Methods Mol Biol 2018; 1708:605-619. [PMID: 29224166 DOI: 10.1007/978-1-4939-7481-8_31] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Blood represents an easily accessible human tissue for numerous research and clinical applications, including surrogate roles for biomarkers of other tissues. Dried blood spots (DBS) are space- and cost-efficient storage forms of blood while stably retaining many of its chemical constituents. Consequently, neonatal DBS are routinely collected in many countries, and their biobanks represent gold mines for research. However, the utility of DBS is restricted by the limited amount and quality of extractable biomolecules (including DNA), especially for genome-wide profiling. In particular, DNA methylome analysis in DBS has proven to be technically challenging, mainly due to the requirement for stringent preprocessing, such as bisulfite conversion. Moreover, DNA amplification, required to increase its yield, often leads to a bias in the analysis, particularly in methylome profiles. Thus, it is important to develop methodologies that maximize both the yield and quality of DNA from DBS for downstream analyses. Using a combination of in-house-derived and modified commercial extraction methods, we developed two robust protocols that produced increased DNA yield and quality from DBS. Though both protocols are more efficient relative to other published methods, one protocol yields less DNA compared to the other, but shows improved 260/280 spectrophotometric ratios, which are useful for sample quality assessment. Both protocols consist of two sequential phases, each involving several critical steps. Phase I comprises blood extraction off the filter papers, cell lysis, and protein digestion. Phase II involves DNA precipitation, purification, and elution. Results from subsequent locus-specific and genome-wide DNA methylation analyses demonstrate the high quality, reproducibility, and consistency of the data. This work may prove useful to meet the increased demand for research on DBS, particularly with a focus on the epigenetic origins of human diseases and newborn screening programs.
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Affiliation(s)
- Akram Ghantous
- Epigenetics Group, International Agency for Research on Cancer (IARC), 150 rue Albert-Thomas, 69008, Lyon, France
| | - Hector Hernandez-Vargas
- Epigenetics Group, International Agency for Research on Cancer (IARC), 150 rue Albert-Thomas, 69008, Lyon, France
| | - Zdenko Herceg
- Epigenetics Group, International Agency for Research on Cancer (IARC), 150 rue Albert-Thomas, 69008, Lyon, France.
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14
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Anderson EL, Banister CE, Kassler S, Messersmith A, Pirisi L, Creek KE, Wyatt MD. Human Papillomavirus Type 16 L2 DNA Methylation in Exfoliated Cervical Cells From College-Age Women. J Low Genit Tract Dis 2016; 20:332-7. [PMID: 27518844 PMCID: PMC5037005 DOI: 10.1097/lgt.0000000000000251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES The Carolina Women's Care Study (CWCS) at the University of South Carolina followed 467 young women with the goal of identifying biomarkers of human papillomavirus (HPV) persistence. In this study, we analyzed the methylation of HPV16 DNA. METHODS The aims of this study were to determine the methylation status of the HPV16 L2 gene in DNA isolated from exfoliated cervical cells collected longitudinally as part of the CWCS and to determine the prevalence of polymorphisms (single nucleotide polymorphisms [SNPs]) in folate metabolizing enzymes and DNA repair enzymes known to affect DNA methylation in blood-derived genomic DNA from CWCS participants. For methylation studies, DNA samples were bisulfite converted and amplified with the EpiTect Whole Bisulfitome kit. Polymerase chain reaction was performed for amplicons containing 5 CpG sites in L2. Pyrosequencing was carried out using EpigenDx and analyzed with PyroMark Software. Taqman genotyping assays were performed to determine selected SNP alleles in the CWCS cohort. RESULTS AND CONCLUSIONS Methylation data were obtained for 82 samples from 27 participants. Of these, 22 participants were positive for HPV16 for 3 or more visits (≥12 months). Methylation in L2 was detectable, but methylation levels varied and were not associated with HPV16 persistence. No linearity of methylation levels over time was observed in participants for whom longitudinal data could be analyzed. Analysis of 9 selected SNPs did not reveal an association with persistence. We conclude that at early stages of infection methylation of HPV16 L2 DNA in Pap test samples is not a predictive biomarker of HPV persistence.
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Affiliation(s)
- Erin L. Anderson
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina
| | - Carolyn E. Banister
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina
| | - Susannah Kassler
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina
| | - Amy Messersmith
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina
- Department of Pharmaceutical Sciences, College of Pharmacy, Presbyterian College
| | - Lucia Pirisi
- Department of Pathology, Microbiology and Immunology, School of Medicine, University of South Carolina
| | - Kim E. Creek
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina
| | - Michael D. Wyatt
- Department of Drug Discovery and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina
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15
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Staunstrup NH, Starnawska A, Nyegaard M, Christiansen L, Nielsen AL, Børglum A, Mors O. Genome-wide DNA methylation profiling with MeDIP-seq using archived dried blood spots. Clin Epigenetics 2016; 8:81. [PMID: 27462375 PMCID: PMC4960904 DOI: 10.1186/s13148-016-0242-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 06/27/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In utero and early-life experienced environmental exposures are suggested to play an important role in many multifactorial diseases potentially mediated through lasting effects on the epigenome. As the epigenome in addition remains modifiable throughout life, identifying specific disease-relevant biomarkers may prove challenging. This has led to an increased interest in epigenome-wide association studies using dried blood spots (DBS) routinely collected in perinatal screening programs. Such programs are in place in numerous countries around the world producing large and unique biobanks. However, availability of this biological material is highly limited as each DBS is made only from a few droplets of blood and storage conditions may be suboptimal for epigenetic studies. Furthermore, as relevant markers may reside outside gene bodies, epigenome-wide interrogation is needed. RESULTS Here we demonstrate, as a proof of principle, that genome-wide interrogation of the methylome based on methylated DNA immunoprecipitation coupled with next-generation sequencing (MeDIP-seq) is feasible using a single 3.2 mm DBS punch (60 ng DNA) from filter cards archived for up to 16 years. The enrichment profile, sequence quality and distribution of reads across genetic regions were comparable between samples archived 16 years, 4 years and a freshly prepared control sample. CONCLUSIONS In summary, we show that high-quality MeDIP-seq data is achievable from neonatal screening filter cards stored at room temperature, thereby providing information on annotated as well as on non-RefSeq genes and repetitive elements. Moreover, the quantity of DNA from one DBS punch proved sufficient allowing for multiple epigenome studies using one single DBS.
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Affiliation(s)
- Nicklas H Staunstrup
- Department of Biomedicine, University of Aarhus, Aarhus C, 8000 Denmark ; Translational Neuropsychiatric Unit, Aarhus University Hospital, Risskov, 8240 Denmark ; The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus C, Denmark
| | - Anna Starnawska
- Department of Biomedicine, University of Aarhus, Aarhus C, 8000 Denmark ; The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus C, Denmark ; Center for Integrative Sequencing, iSEQ, AU, Aarhus C, Denmark
| | - Mette Nyegaard
- Department of Biomedicine, University of Aarhus, Aarhus C, 8000 Denmark ; The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus C, Denmark ; Center for Integrative Sequencing, iSEQ, AU, Aarhus C, Denmark
| | - Lene Christiansen
- Department of Public Health, University of Southern Denmark, Odense C, 5000 Denmark
| | - Anders L Nielsen
- Department of Biomedicine, University of Aarhus, Aarhus C, 8000 Denmark ; The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus C, Denmark
| | - Anders Børglum
- Department of Biomedicine, University of Aarhus, Aarhus C, 8000 Denmark ; Research Department P, Aarhus University Hospital, Risskov, 8240 Denmark ; The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus C, Denmark ; Center for Integrative Sequencing, iSEQ, AU, Aarhus C, Denmark
| | - Ole Mors
- Translational Neuropsychiatric Unit, Aarhus University Hospital, Risskov, 8240 Denmark ; Research Department P, Aarhus University Hospital, Risskov, 8240 Denmark ; The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus C, Denmark
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16
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Current and Emerging Technologies for the Analysis of the Genome-Wide and Locus-Specific DNA Methylation Patterns. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 945:343-430. [DOI: 10.1007/978-3-319-43624-1_15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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17
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Ghantous A, Saffery R, Cros MP, Ponsonby AL, Hirschfeld S, Kasten C, Dwyer T, Herceg Z, Hernandez-Vargas H. Optimized DNA extraction from neonatal dried blood spots: application in methylome profiling. BMC Biotechnol 2014; 14:60. [PMID: 24980254 PMCID: PMC4086704 DOI: 10.1186/1472-6750-14-60] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 06/20/2014] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Neonatal dried blood spots (DBS) represent an inexpensive method for long-term biobanking worldwide and are considered gold mines for research for several human diseases, including those of metabolic, infectious, genetic and epigenetic origin. However, the utility of DBS is restricted by the limited amount and quality of extractable biomolecules (including DNA), especially for genome wide profiling. Degradation of DNA in DBS often occurs during storage and extraction. Moreover, amplifying small quantities of DNA often leads to a bias in subsequent data, particularly in methylome profiles. Thus it is important to develop methodologies that maximize both the yield and quality of DNA from DBS for downstream analyses. RESULTS Using combinations of in-house-derived and modified commercial extraction kits, we developed a robust and efficient protocol, compatible with methylome studies, many of which require stringent bisulfite conversion steps. Several parameters were tested in a step-wise manner, including blood extraction, cell lysis, protein digestion, and DNA precipitation, purification and elution. DNA quality was assessed based on spectrophotometric measurements, DNA detectability by PCR, and DNA integrity by gel electrophoresis and bioanalyzer analyses. Genome scale Infinium HumanMethylation450 and locus-specific pyrosequencing data generated using the refined DBS extraction protocol were of high quality, reproducible and consistent. CONCLUSIONS This study may prove useful to meet the increased demand for research on prenatal, particularly epigenetic, origins of human diseases and for newborn screening programs, all of which are often based on DNA extracted from DBS.
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Affiliation(s)
- Akram Ghantous
- Epigenetics Group, International Agency for Research on Cancer (IARC), 150 rue Albert-Thomas, 69008 Lyon, France
| | - Richard Saffery
- Cancer and Disease Epigenetics, Murdoch Childrens Research Institute Royal Children's Hospital, Flemington Road Parkville, Victoria 3052, Australia
| | - Marie-Pierre Cros
- Epigenetics Group, International Agency for Research on Cancer (IARC), 150 rue Albert-Thomas, 69008 Lyon, France
| | - Anne-Louise Ponsonby
- Environmental & Genetic Epidemiology Research, Murdoch Children’s Research Institute Royal Children’s Hospital, Flemington Road Parkville, Victoria 3052, Australia
- Menzies Research Institute, University of Tasmania, Hobart TAS 7000, Australia
| | - Steven Hirschfeld
- Department of Health and Human Services, National Children’s Study, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health U.S., 6100 Executive Boulevard, Room 3A01, Bethesda, MD 20892, USA
| | - Carol Kasten
- Department of Health and Human Services, National Children’s Study, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health U.S., 6100 Executive Boulevard, Room 3A01, Bethesda, MD 20892, USA
| | - Terence Dwyer
- Environmental & Genetic Epidemiology Research, Murdoch Children’s Research Institute Royal Children’s Hospital, Flemington Road Parkville, Victoria 3052, Australia
- Menzies Research Institute, University of Tasmania, Hobart TAS 7000, Australia
- Chair, Steering Committtee, International Childhood Cancer Cohort Consortium (I4C
| | - Zdenko Herceg
- Epigenetics Group, International Agency for Research on Cancer (IARC), 150 rue Albert-Thomas, 69008 Lyon, France
| | - Hector Hernandez-Vargas
- Epigenetics Group, International Agency for Research on Cancer (IARC), 150 rue Albert-Thomas, 69008 Lyon, France
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18
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Paul DS, Guilhamon P, Karpathakis A, Butcher LM, Thirlwell C, Feber A, Beck S. Assessment of RainDrop BS-seq as a method for large-scale, targeted bisulfite sequencing. Epigenetics 2014; 9:678-84. [PMID: 24518816 PMCID: PMC4063826 DOI: 10.4161/epi.28041] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
We present a systematic assessment of RainDrop BS-seq, a novel method for large-scale, targeted bisulfite sequencing using microdroplet-based PCR amplification coupled with next-generation sequencing. We compared DNA methylation levels at 498 target loci (1001 PCR amplicons) in human whole blood, osteosarcoma cells and an archived tumor tissue sample. We assessed the ability of RainDrop BS-seq to accurately measure DNA methylation over a range of DNA quantities (from 10 to 1500 ng), both with and without whole-genome amplification (WGA) following bisulfite conversion. DNA methylation profiles generated using at least 100 ng correlated well (median R = 0.92) with those generated on Illumina Infinium HumanMethylation450 BeadChips, currently the platform of choice for epigenome-wide association studies (EWAS). WGA allowed for testing of samples with a starting DNA amount of 10 and 50 ng, although a reduced correlation was observed (median R = 0.79). We conclude that RainDrop BS-seq is suitable for measuring DNA methylation levels using nanogram quantities of DNA, and can be used to study candidate epigenetic biomarker loci in an accurate and high-throughput manner, paving the way for its application to routine clinical diagnostics.
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Affiliation(s)
- Dirk S Paul
- UCL Cancer Institute; University College London; London, United Kingdom
| | - Paul Guilhamon
- UCL Cancer Institute; University College London; London, United Kingdom
| | - Anna Karpathakis
- UCL Cancer Institute; University College London; London, United Kingdom
| | - Lee M Butcher
- UCL Cancer Institute; University College London; London, United Kingdom
| | | | - Andrew Feber
- UCL Cancer Institute; University College London; London, United Kingdom
| | - Stephan Beck
- UCL Cancer Institute; University College London; London, United Kingdom
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Abstract
We all start out as a single totipotent cell that is programmed to produce a multicellular organism. How do individual cells make those complex developmental switches? How do single cells within a tissue or organ differ, how do they coordinate their actions or go astray in a disease process? These are long-standing and fundamental questions in biology that are now becoming tractable because of advances in microfluidics, DNA amplification and DNA sequencing. Methods for studying single-cell transcriptomes (or at least the polyadenylated mRNA fraction of it) are by far the furthest ahead and reveal remarkable heterogeneity between morphologically identical cells. The analysis of genomic DNA variation is not far behind. The other 'omics' of single cells pose greater technological obstacles, but they are progressing and promise to yield highly integrated large data sets in the near future.
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20
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Li Y, Xu J, Chen H, Zhao Z, Li S, Bai J, Wu A, Jiang C, Wang Y, Su B, Li X. Characterizing genes with distinct methylation patterns in the context of protein-protein interaction network: application to human brain tissues. PLoS One 2013; 8:e65871. [PMID: 23776563 PMCID: PMC3680465 DOI: 10.1371/journal.pone.0065871] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 04/29/2013] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND DNA methylation is an essential epigenetic mechanism involved in transcriptional control. However, how genes with different methylation patterns are assembled in the protein-protein interaction network (PPIN) remains a mystery. RESULTS In the present study, we systematically dissected the characterization of genes with different methylation patterns in the PPIN. A negative association was detected between the methylation levels in the brain tissues and topological centralities. By focusing on two classes of genes with considerably different methylation levels in the brain tissues, namely the low methylated genes (LMGs) and high methylated genes (HMGs), we found that their organizing principles in the PPIN are distinct. The LMGs tend to be the center of the PPIN, and attacking them causes a more deleterious effect on the network integrity. Furthermore, the LMGs express their functions in a modular pattern and substantial differences in functions are observed between the two types of genes. The LMGs are enriched in the basic biological functions, such as binding activity and regulation of transcription. More importantly, cancer genes, especially recessive cancer genes, essential genes, and aging-related genes were all found more often in the LMGs. Additionally, our analysis presented that the intra-classes communications are enhanced, but inter-classes communications are repressed. Finally, a functional complementation was revealed between methylation and miRNA regulation in the human genome. CONCLUSIONS We have elucidated the assembling principles of genes with different methylation levels in the context of the PPIN, providing key insights into the complex epigenetic regulation mechanisms.
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Affiliation(s)
- Yongsheng Li
- College of Bioinformatics Science and Technology, Harbin Medical University, Harbin, China
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