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Noor DAM, Jeyapalan JN, Alhazmi S, Carr M, Squibb B, Wallace C, Tan C, Cusack M, Hughes J, Reader T, Shipley J, Sheer D, Scotting PJ. Genome-wide methylation analysis identifies genes silenced in non-seminoma cell lines. NPJ Genom Med 2016; 1:15009. [PMID: 29263807 PMCID: PMC5685295 DOI: 10.1038/npjgenmed.2015.9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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] [Received: 07/02/2015] [Revised: 10/09/2015] [Accepted: 11/06/2015] [Indexed: 01/13/2023] Open
Abstract
Silencing of genes by DNA methylation is a common phenomenon in many types of cancer. However, the genome-wide effect of DNA methylation on gene expression has been analysed in relatively few cancers. Germ cell tumours (GCTs) are a complex group of malignancies. They are unique in developing from a pluripotent progenitor cell. Previous analyses have suggested that non-seminomas exhibit much higher levels of DNA methylation than seminomas. The genomic targets that are methylated, the extent to which this results in gene silencing and the identity of the silenced genes most likely to play a role in the tumours’ biology have not yet been established. In this study, genome-wide methylation and expression analysis of GCT cell lines was combined with gene expression data from primary tumours to address this question. Genome methylation was analysed using the Illumina infinium HumanMethylome450 bead chip system and gene expression was analysed using Affymetrix GeneChip Human Genome U133 Plus 2.0 arrays. Regulation by methylation was confirmed by demethylation using 5-aza-2-deoxycytidine and reverse transcription–quantitative PCR. Large differences in the level of methylation of the CpG islands of individual genes between tumour cell lines correlated well with differential gene expression. Treatment of non-seminoma cells with 5-aza-2-deoxycytidine verified that methylation of all genes tested played a role in their silencing in yolk sac tumour cells and many of these genes were also differentially expressed in primary tumours. Genes silenced by methylation in the various GCT cell lines were identified. Several pluripotency-associated genes were identified as a major functional group of silenced genes.
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Affiliation(s)
- Dzul Azri Mohamed Noor
- School of Life Sciences, University of Nottingham, Nottingham, UK.,School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia
| | - Jennie N Jeyapalan
- School of Life Sciences, University of Nottingham, Nottingham, UK.,The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, London, UK
| | - Safiah Alhazmi
- School of Life Sciences, University of Nottingham, Nottingham, UK.,Biology Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Matthew Carr
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Benjamin Squibb
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Claire Wallace
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Christopher Tan
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Martin Cusack
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Jaime Hughes
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Tom Reader
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Janet Shipley
- Divisions of Molecular Pathology and Cancer Therapeutics, The Institute of Cancer Research, London, UK
| | - Denise Sheer
- The Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, London, UK
| | - Paul J Scotting
- School of Life Sciences, University of Nottingham, Nottingham, UK
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