ABSTRACT: Genome-wide analysis of DNA methylation in neuroblastoma cell lines identifies MEGF10 as a novel epigenetically repressed tumour suppressor gene.
Project description:Background: Neuroblastoma is a childhood cancer in which many children still have poor outcomes, emphasising the need to better understand its pathogenesis. Despite recent genome-wide mutation analyses, most neuroblastomas do not contain recognisable driver mutations, suggesting that epigenetic changes could underlie many cases. Methods: To discover genes that become epigenetically deregulated during neuroblastoma tumorigenesis, we compared neuroblastomas to their neural crest precursor cells, using genome-wide DNA methylation analysis; probing CpG island promoter microarrays with methyl CpG-immunoprecipitated DNA. Results: We identified 93 genes that were significantly differently methylated between neuroblastoma cell lines and neural crest cells, of which 26 (28%) were hypermethylated and 67 (72%) were hypomethylated. Concentrating on hypermethylated genes to identify candidate tumour suppressor loci, we found the cell engulfment and adhesion factor gene MEGF10 to be epigenetically repressed by DNA hypermethylation or by H3K27/K9 methylation in neuroblastoma cell lines. MEGF10 showed significantly down-regulated expression in neuroblastoma tumour samples; furthermore patients with the lowest-expressing tumours had reduced relapse-free survival. Knock-down of MEGF10 expression in neuroblastoma cell lines promoted cell growth. Conclusion: Our results suggest that MEGF10 is a clinically relevant, epigenetically-deregulated neuroblastoma tumour suppressor.
Project description:Promoter region hypermethylation and transcriptional silencing is a frequent cause of tumour suppressor gene (TSG) inactivation in many types of human cancers. Functional epigenetic studies, in which gene expression is induced by treatment with demethylating agents, may identify novel genes with tumour-specific methylation. We used high-density gene expression microarrays in a functional epigenetic study of 11 renal cell carcinoma (RCC) cell lines. Twenty eight genes were then selected for analysis of promoter methylation status in cell lines and primary RCC. Eight genes (BNC1, PDLIM4/RIL, REPRIMORPRM, CST6, SFRP1, GREM1, COL14A1 and COL15A1) demonstrated frequent (>30% of RCC tested) tumour-specific promoter region methylation. Hypermethylation was associated with transcriptional silencing. Re-expression of BNC1, CST6, RPRM, and SFRP1 suppressed the growth of RCC cell lines. Whereas, RNAi-knock-down of BNC1, SFRP1 and COL14A1 increased the growth potential of RCC cell lines. Methylation of BNC1 or COL14A1 was associated with a poorer prognosis independent of tumour size, stage or grade. The identification of these epigenetically inactivated candidate RCC tumour suppressor genes can provide insights into renal tumourigenesis and a basis for developing novel therapies and biomarkers for prognosis and detection. We used expression microarrays to identified genes that were frequently methylated and silenced in RCC by determining the globlal expression patterns of RCC-derived cell lines following de-methylation by treatment with 5-Aza-2'-deoxycytidine.
Project description:Promoter region hypermethylation and transcriptional silencing is a frequent cause of tumour suppressor gene (TSG) inactivation in many types of human cancers. Functional epigenetic studies, in which gene expression is induced by treatment with demethylating agents, may identify novel genes with tumour-specific methylation. We used high-density gene expression microarrays in a functional epigenetic study of 11 renal cell carcinoma (RCC) cell lines. Twenty eight genes were then selected for analysis of promoter methylation status in cell lines and primary RCC. Eight genes (BNC1, PDLIM4/RIL, REPRIMORPRM, CST6, SFRP1, GREM1, COL14A1 and COL15A1) demonstrated frequent (>30% of RCC tested) tumour-specific promoter region methylation. Hypermethylation was associated with transcriptional silencing. Re-expression of BNC1, CST6, RPRM, and SFRP1 suppressed the growth of RCC cell lines. Whereas, RNAi-knock-down of BNC1, SFRP1 and COL14A1 increased the growth potential of RCC cell lines. Methylation of BNC1 or COL14A1 was associated with a poorer prognosis independent of tumour size, stage or grade. The identification of these epigenetically inactivated candidate RCC tumour suppressor genes can provide insights into renal tumourigenesis and a basis for developing novel therapies and biomarkers for prognosis and detection.
Project description:Alcohol is a major risk factor for hepatocellular carcinoma (HCC) although the mechanisms underlying the alcohol-related liver carcinogenesis are still poorly understood. Alcohol is known to increase hepatocarcinogenesis possibly by inducing aberrant DNA methylation through the reduced provision of methyl groups within the hepatic one-carbon metabolism. Whether the epigenetically-regulated pathways in alcohol-associated HCC can be reversible or modifiable by nutritional factors is unknown. The aim of the present study was to investigate the genome wide promoter DNA methylation profiles along with array-based, gene expression profiles in non-viral, alcohol-associated HCC. From eight HCC patients the methylation status and transcriptional levels of all annotated genes were compared by analyzing HCC tissue and the cancer-free surrounding liver tissue, following curative surgery. After merging both the DNA methylation and gene expression data, we identified 159 hypermethylated-repressed, 30 hypomethylated-induced, 49 hypermethylated-induced and 56 hypomethylated-repressed genes. A number of potentially novel candidate tumor-suppressor genes (FAM107A, IGFALS, MT1G, MT1H, RNF180) demonstrated promoter hypermethylation and transcriptional repression in alcohol-associated HCC. Notably, promoter DNA methylation appeared as the regulatory mechanism for the transcriptional repression of genes controlling the retinol metabolic pathway (ADH1A, ADH1B, ADH6, CYP3A43, CYP4A22, RDH16) and SHMT1, a key gene within one-carbon metabolism. A genome-wide DNA methylation approach linked up with array-based gene expression profiles allowed identifying a number of novel, epigenetically-regulated candidate tumor-suppressor genes in alcohol-associated hepatocarcinogenesis. Retinol metabolism genes and SHMT1 are also epigenetically-regulated through promoter DNA methylation in alcohol-associated hepatocarcinogenesis. 16 samples (8 control samples from non-neoplastic liver tissue, 8 test samples from hepatocellular carcinoma) from 8 patients affected from hepatocellular carcinoma were analyzed.
Project description:Alcohol is a major risk factor for hepatocellular carcinoma (HCC) although the mechanisms underlying the alcohol-related liver carcinogenesis are still poorly understood. Alcohol is known to increase hepatocarcinogenesis possibly by inducing aberrant DNA methylation through the reduced provision of methyl groups within the hepatic one-carbon metabolism. Whether the epigenetically-regulated pathways in alcohol-associated HCC can be reversible or modifiable by nutritional factors is unknown. The aim of the present study was to investigate the genome wide promoter DNA methylation profiles along with array-based, gene expression profiles in non-viral, alcohol-associated HCC. From eight HCC patients the methylation status and transcriptional levels of all annotated genes were compared by analyzing HCC tissue and the cancer-free surrounding liver tissue, following curative surgery. After merging both the DNA methylation and gene expression data, we identified 159 hypermethylated-repressed, 30 hypomethylated-induced, 49 hypermethylated-induced and 56 hypomethylated-repressed genes. A number of potentially novel candidate tumor-suppressor genes (FAM107A, IGFALS, MT1G, MT1H, RNF180) demonstrated promoter hypermethylation and transcriptional repression in alcohol-associated HCC. Notably, promoter DNA methylation appeared as the regulatory mechanism for the transcriptional repression of genes controlling the retinol metabolic pathway (ADH1A, ADH1B, ADH6, CYP3A43, CYP4A22, RDH16) and SHMT1, a key gene within one-carbon metabolism. A genome-wide DNA methylation approach linked up with array-based gene expression profiles allowed identifying a number of novel, epigenetically-regulated candidate tumor-suppressor genes in alcohol-associated hepatocarcinogenesis. Retinol metabolism genes and SHMT1 are also epigenetically-regulated through promoter DNA methylation in alcohol-associated hepatocarcinogenesis. 16 samples (8 control samples from non-neoplastic liver tissue, 8 test samples from hepatocellular carcinoma) from 8 patients affected from hepatocellular carcinoma were analyzed.
Project description:Alcohol is a major risk factor for hepatocellular carcinoma (HCC) although the mechanisms underlying the alcohol-related liver carcinogenesis are still poorly understood. Alcohol is known to increase hepatocarcinogenesis possibly by inducing aberrant DNA methylation through the reduced provision of methyl groups within the hepatic one-carbon metabolism. Whether the epigenetically-regulated pathways in alcohol-associated HCC can be reversible or modifiable by nutritional factors is unknown. The aim of the present study was to investigate the genome wide promoter DNA methylation profiles along with array-based, gene expression profiles in non-viral, alcohol-associated HCC. From eight HCC patients the methylation status and transcriptional levels of all annotated genes were compared by analyzing HCC tissue and the cancer-free surrounding liver tissue, following curative surgery. After merging both the DNA methylation and gene expression data, we identified 159 hypermethylated-repressed, 30 hypomethylated-induced, 49 hypermethylated-induced and 56 hypomethylated-repressed genes. A number of potentially novel candidate tumor-suppressor genes (FAM107A, IGFALS, MT1G, MT1H, RNF180) demonstrated promoter hypermethylation and transcriptional repression in alcohol-associated HCC. Notably, promoter DNA methylation appeared as the regulatory mechanism for the transcriptional repression of genes controlling the retinol metabolic pathway (ADH1A, ADH1B, ADH6, CYP3A43, CYP4A22, RDH16) and SHMT1, a key gene within one-carbon metabolism. A genome-wide DNA methylation approach linked up with array-based gene expression profiles allowed identifying a number of novel, epigenetically-regulated candidate tumor-suppressor genes in alcohol-associated hepatocarcinogenesis. Retinol metabolism genes and SHMT1 are also epigenetically-regulated through promoter DNA methylation in alcohol-associated hepatocarcinogenesis.
Project description:Alcohol is a major risk factor for hepatocellular carcinoma (HCC) although the mechanisms underlying the alcohol-related liver carcinogenesis are still poorly understood. Alcohol is known to increase hepatocarcinogenesis possibly by inducing aberrant DNA methylation through the reduced provision of methyl groups within the hepatic one-carbon metabolism. Whether the epigenetically-regulated pathways in alcohol-associated HCC can be reversible or modifiable by nutritional factors is unknown. The aim of the present study was to investigate the genome wide promoter DNA methylation profiles along with array-based, gene expression profiles in non-viral, alcohol-associated HCC. From eight HCC patients the methylation status and transcriptional levels of all annotated genes were compared by analyzing HCC tissue and the cancer-free surrounding liver tissue, following curative surgery. After merging both the DNA methylation and gene expression data, we identified 159 hypermethylated-repressed, 30 hypomethylated-induced, 49 hypermethylated-induced and 56 hypomethylated-repressed genes. A number of potentially novel candidate tumor-suppressor genes (FAM107A, IGFALS, MT1G, MT1H, RNF180) demonstrated promoter hypermethylation and transcriptional repression in alcohol-associated HCC. Notably, promoter DNA methylation appeared as the regulatory mechanism for the transcriptional repression of genes controlling the retinol metabolic pathway (ADH1A, ADH1B, ADH6, CYP3A43, CYP4A22, RDH16) and SHMT1, a key gene within one-carbon metabolism. A genome-wide DNA methylation approach linked up with array-based gene expression profiles allowed identifying a number of novel, epigenetically-regulated candidate tumor-suppressor genes in alcohol-associated hepatocarcinogenesis. Retinol metabolism genes and SHMT1 are also epigenetically-regulated through promoter DNA methylation in alcohol-associated hepatocarcinogenesis.
Project description:The epithelial splicing regulator ESRP2 is epigenetically repressed by DNA hypermethylation in Wilms tumour and acts as a tumour suppressor
Project description:Genome wide DNA methylation profiling of 20 PDAC cell lines and an immortalized non-malignant pancreatic duct cell line (HPDE) to facilitate identification of novel tumor suppressor genes using an integrative genomics approach Genome wide DNA methylation profiling of 20 PDAC cell lines and an immortalized non-malignant pancreatic duct cell line (HPDE) to identify novel tumor suppressor genes
Project description:In mammals, many germline genes are repressed by epigenetic mechanisms to prevent their illegitimate expression in embryonic and somatic cells. To advance our understanding of the complete mechanisms restricting the expression of germline genes in mammals, we analyzed the chromatin signature of germline genes and performed a genome-wide CRISPR-Cas9 knock-out screen for genes involved in germline gene repression using a reporter system in which GFP is under the control of the epigenetically repressed Dazl germline promoter in mouse embryonic stem cells (ESCs). We showed that the repression of germline genes mainly depends on the polycomb complex PRC1.6 and DNA methylation, which function additively in mouse ESCs. Furthermore, we identified and validated several novel genes involved in the repression of germline genes, and characterized three of them: Usp7, Shfm1 (also known as Sem1) and Erh. Inactivation of Usp7, Shfm1 or Erh led to the upregulation of germline genes, as well as retrotransposons for Shfm1, in mouse ESCs. Functionally, Usp7 acts at two levels: firstly it associates with PRC1.6 components and represses germline genes independently of DNA methylation, and secondly it facilitates DNA methylation deposition at germline genes for long term repression. In summary, our study provides a global view of the epigenetic mechanisms and novel factors required for silencing germline genes in embryonic cells.