Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA116593 | ENA |
REPOSITORIES: ENA
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Project description:Cancer is characterised by DNA hypermethylation and gene silencing of CpG island-associated promoters, including tumour suppressor genes The methyl-CpG-binding domain (MBD) family of proteins bind to methylated DNA and can aid in the meditation of gene silencing by interaction with histone deacetylases and histone methyltransferases. However the mechanisms responsible for eliciting CpG island hypermethylation in cancer, and the potential role that MBD may proteins play in modulation of the methylome remain unclear. Our previous work demonstrated that MBD2 preferentially binds to the hypermethylated GSTP1 promoter CpG island in prostate cancer cells. Here, we use functional genetic approaches to investigate if MBD2 plays an active role in promoting DNA methylation. First, we show that loss of MBD2 results in inhibition of both maintenance and spread of de novo methylation of a transfected construct containing the GSTP1 promoter CpG island in prostate cancer cells and Mbd2-/- mouse fibroblasts. De novo methylation was rescued by transient expression of Mbd2 in Mbd2-/- cells. Second, we show that MBD2 depletion triggers significant hypomethylation genome-wide in prostate cancer cells with concomitant loss of MBD2 binding at promoter and enhancer regulatory regions. Finally, CpG islands and shores that become hypomethylated after MBD2 depletion in LNCaP cancer cells show significant hypermethylation in clinical prostate cancer, highlighting a potential active role of MBD2 in promoting cancer specific hypermethylation. Importantly, co-immunoprecipiation of MBD2 reveals that MBD2 associates with DNA methyltransferase (DNMT) enzymes 1 and 3A. Together our results demonstrate that MBD2 plays a critical role in “rewriting” the cancer methylome at specific regulatory regions.
2016-08-24 | GSE77201 | GEO
Project description:Cancer is characterised by DNA hypermethylation and gene silencing of CpG island-associated promoters, including tumour suppressor genes The methyl-CpG-binding domain (MBD) family of proteins bind to methylated DNA and can aid in the meditation of gene silencing by interaction with histone deacetylases and histone methyltransferases. However the mechanisms responsible for eliciting CpG island hypermethylation in cancer, and the potential role that MBD may proteins play in modulation of the methylome remain unclear. Our previous work demonstrated that MBD2 preferentially binds to the hypermethylated GSTP1 promoter CpG island in prostate cancer cells. Here, we use functional genetic approaches to investigate if MBD2 plays an active role in promoting DNA methylation. First, we show that loss of MBD2 results in inhibition of both maintenance and spread of de novo methylation of a transfected construct containing the GSTP1 promoter CpG island in prostate cancer cells and Mbd2-/- mouse fibroblasts. De novo methylation was rescued by transient expression of Mbd2 in Mbd2-/- cells. Second, we show that MBD2 depletion triggers significant hypomethylation genome-wide in prostate cancer cells with concomitant loss of MBD2 binding at promoter and enhancer regulatory regions. Finally, CpG islands and shores that become hypomethylated after MBD2 depletion in LNCaP cancer cells show significant hypermethylation in clinical prostate cancer, highlighting a potential active role of MBD2 in promoting cancer specific hypermethylation. Importantly, co-immunoprecipiation of MBD2 reveals that MBD2 associates with DNA methyltransferase (DNMT) enzymes 1 and 3A. Together our results demonstrate that MBD2 plays a critical role in “rewriting” the cancer methylome at specific regulatory regions.
2016-08-24 | GSE77187 | GEO
Project description:Cancer is characterised by DNA hypermethylation and gene silencing of CpG island-associated promoters, including tumour suppressor genes The methyl-CpG-binding domain (MBD) family of proteins bind to methylated DNA and can aid in the meditation of gene silencing by interaction with histone deacetylases and histone methyltransferases. However the mechanisms responsible for eliciting CpG island hypermethylation in cancer, and the potential role that MBD may proteins play in modulation of the methylome remain unclear. Our previous work demonstrated that MBD2 preferentially binds to the hypermethylated GSTP1 promoter CpG island in prostate cancer cells. Here, we use functional genetic approaches to investigate if MBD2 plays an active role in promoting DNA methylation. First, we show that loss of MBD2 results in inhibition of both maintenance and spread of de novo methylation of a transfected construct containing the GSTP1 promoter CpG island in prostate cancer cells and Mbd2-/- mouse fibroblasts. De novo methylation was rescued by transient expression of Mbd2 in Mbd2-/- cells. Second, we show that MBD2 depletion triggers significant hypomethylation genome-wide in prostate cancer cells with concomitant loss of MBD2 binding at promoter and enhancer regulatory regions. Finally, CpG islands and shores that become hypomethylated after MBD2 depletion in LNCaP cancer cells show significant hypermethylation in clinical prostate cancer, highlighting a potential active role of MBD2 in promoting cancer specific hypermethylation. Importantly, co-immunoprecipiation of MBD2 reveals that MBD2 associates with DNA methyltransferase (DNMT) enzymes 1 and 3A. Together our results demonstrate that MBD2 plays a critical role in â??rewritingâ?? the cancer methylome at specific regulatory regions. LNCaP prostate cancer cell line clones with reduced MBD2 expression were establised by using shRNA to MBD2 and scrambled control clones were established with scrambled control shRNA. To interrogate methylation changes induced by MBD2 knock-down we profiled three stably transfected scrambled control clones and three MBD2 knockdown clones on Illumina HumanMethylation450K arrays. Differential methylation analysis was carried out to identified CpG sites hypo-/hyper-methylated as a result of MBD2 knockdown.
2016-08-24 | E-GEOD-77201 | biostudies-arrayexpress
Project description:Astrocytomas are common and lethal human brain tumors. Here, we have analyzed the methylation status of over 28,000 CpG islands and 18,000 promoters in normal human brain and in astrocytomas of various grades using the methylated-CpG island recovery assay (MIRA). We identified six to seven thousand methylated CpG islands in normal human brain. ~5% of the promoter-associated CpG islands in normal brain are methylated. Promoter CpG island methylation is inversely and intragenic methylation is directly correlated with gene expression levels in brain tissue. In astrocytomas, several hundred CpG islands undergo specific hypermethylation relative to normal brain with 428 methylation peaks common to more than 25% of the tumors. Genes involved in brain development and neuronal differentiation, such as POU4F3, GDNF, OTX2, NEFM, CNTN4, OTP, SIM1, FYN, EN1, CHAT, GSX2, NKX6-1, RAX, PAX6, DLX2, were strongly enriched among genes frequently methylated in tumors. There was an overrepresentation of homeobox genes and 31% of the most commonly methylated genes represent targets of the Polycomb complex. We identified several chromosomal loci in which many (sometimes more than 20) consecutive CpG islands were hypermethylated in tumors. Seven of such loci were near homeobox genes, including the HOXC and HOXD clusters, and the BARHL2, DLX1, and PITX2 genes. Two other clusters of hypermethylated islands were at sequences of recent gene duplication events. Our analysis offers mechanistic insights into brain neoplasia suggesting that methylation of genes involved in neuronal differentiation, perhaps in cooperation with other oncogenic events, may shift the balance from regulated differentiation towards gliomagenesis. Comparison of methylation patterns of 30 astrocytomas and 6 controls
2010-05-16 | E-GEOD-19391 | biostudies-arrayexpress
Project description:Cancer is characterised by DNA hypermethylation and gene silencing of CpG island-associated promoters, including tumour suppressor genes The methyl-CpG-binding domain (MBD) family of proteins bind to methylated DNA and can aid in the meditation of gene silencing by interaction with histone deacetylases and histone methyltransferases. However the mechanisms responsible for eliciting CpG island hypermethylation in cancer, and the potential role that MBD may proteins play in modulation of the methylome remain unclear. Our previous work demonstrated that MBD2 preferentially binds to the hypermethylated GSTP1 promoter CpG island in prostate cancer cells. Here, we use functional genetic approaches to investigate if MBD2 plays an active role in promoting DNA methylation. First, we show that loss of MBD2 results in inhibition of both maintenance and spread of de novo methylation of a transfected construct containing the GSTP1 promoter CpG island in prostate cancer cells and Mbd2-/- mouse fibroblasts. De novo methylation was rescued by transient expression of Mbd2 in Mbd2-/- cells. Second, we show that MBD2 depletion triggers significant hypomethylation genome-wide in prostate cancer cells with concomitant loss of MBD2 binding at promoter and enhancer regulatory regions. Finally, CpG islands and shores that become hypomethylated after MBD2 depletion in LNCaP cancer cells show significant hypermethylation in clinical prostate cancer, highlighting a potential active role of MBD2 in promoting cancer specific hypermethylation. Importantly, co-immunoprecipiation of MBD2 reveals that MBD2 associates with DNA methyltransferase (DNMT) enzymes 1 and 3A. Together our results demonstrate that MBD2 plays a critical role in ârewritingâ the cancer methylome at specific regulatory regions. LNCaP prostate cancer cell line clones with reduced MBD2 expression were establised by using shRNA to MBD2 and scrambled control clones were established with scrambled control shRNA. To interrogate expression changes induced by MBD2 knock-down we profiled three stably transfected scrambled control clones and three MBD2 knockdown clones on Affymetrix HuGene 1.0ST expression arrays. Differential expression analysis was carried out to identified genes up-/down-regulated by MBD2 knockdown.
2016-08-24 | E-GEOD-77187 | biostudies-arrayexpress
Project description:Astrocytomas are common and lethal human brain tumors. Here, we have analyzed the methylation status of over 28,000 CpG islands and 18,000 promoters in normal human brain and in astrocytomas of various grades using the methylated-CpG island recovery assay (MIRA). We identified six to seven thousand methylated CpG islands in normal human brain. ~5% of the promoter-associated CpG islands in normal brain are methylated. Promoter CpG island methylation is inversely and intragenic methylation is directly correlated with gene expression levels in brain tissue. In astrocytomas, several hundred CpG islands undergo specific hypermethylation relative to normal brain with 428 methylation peaks common to more than 25% of the tumors. Genes involved in brain development and neuronal differentiation, such as POU4F3, GDNF, OTX2, NEFM, CNTN4, OTP, SIM1, FYN, EN1, CHAT, GSX2, NKX6-1, RAX, PAX6, DLX2, were strongly enriched among genes frequently methylated in tumors. There was an overrepresentation of homeobox genes and 31% of the most commonly methylated genes represent targets of the Polycomb complex. We identified several chromosomal loci in which many (sometimes more than 20) consecutive CpG islands were hypermethylated in tumors. Seven of such loci were near homeobox genes, including the HOXC and HOXD clusters, and the BARHL2, DLX1, and PITX2 genes. Two other clusters of hypermethylated islands were at sequences of recent gene duplication events. Our analysis offers mechanistic insights into brain neoplasia suggesting that methylation of genes involved in neuronal differentiation, perhaps in cooperation with other oncogenic events, may shift the balance from regulated differentiation towards gliomagenesis.
2010-01-01 | GSE19391 | GEO
Project description:In order to identify methylation changes in prostate cancer, we performed a genome-wide analysis of DNA methylation using Agilent human CpG island arrays. We then chose specific genes to validate methylation both in the same cases as were hybridized to the array (using quantitative EpiTYPER analysis) and in an independent series of prostate cancer samples (using MethyLight quantitative methylation specific PCR). We specifically chose low grade (Gleason score 6 cases) and high grade (Gleason score 8 cases) to discover methylated genes/loci that may be involved in the progression to a higher grade of prostate cancer.
2009-03-27 | GSE15298 | GEO
Project description:To screen candidate methylation markers for early detection of breast cancer, we performed methylated-CpG island recovery assay combined with CpG island array on 61982 CpG sites across 4162 genes in 10 breast tumor tissues and 10 non-tumor breast tissues. We detected 70 significantly hypermethylated genes in breast tumor tissues, including many novel hypermethylated genes such as ITGA4, NFIX, OTX2 and FGF12. Direct bisulfite sequencing showed widespread methylations occurred in intragenic regions of WT1, PAX6 and ITGA4 genes and promoter region of OTX2 in breast cancer tissue. COBRA assay in independent tumor and non-tumor samples confirmed that WT1, OTX2 and PAX6 genes were hypermethylated in breast cancer tissues. To explore the relationship between methylation and gene expression, gene expression profiling analysis was performed in 8 breast tumor tissues and 8 non-tumor breast tissues. We found that some hypermethylated genes in breast cancer were not expressed in breast tissues. RT-PCR assay showed that WT1 and PITX2 were only weakly expressed in the breast tumor tissues and weren’t expressed in most non-tumor breast tissues. OTX2 and PAX6 weren’t expressed in both breast tumor tissues and non-tumor tissues.
2011-11-11 | GSE33447 | GEO
Project description:To screen candidate methylation markers for early detection of breast cancer, we performed methylated-CpG island recovery assay combined with CpG island array on 61982 CpG sites across 4162 genes in 10 breast tumor tissues and 10 non-tumor breast tissues. We detected 70 significantly hypermethylated genes in breast tumor tissues, including many novel hypermethylated genes such as ITGA4, NFIX, OTX2 and FGF12. Direct bisulfite sequencing showed widespread methylations occurred in intragenic regions of WT1, PAX6 and ITGA4 genes and promoter region of OTX2 in breast cancer tissue. COBRA assay in independent tumor and non-tumor samples confirmed that WT1, OTX2 and PAX6 genes were hypermethylated in breast cancer tissues. To explore the relationship between methylation and gene expression, gene expression profiling analysis was performed in 8 breast tumor tissues and 8 non-tumor breast tissues. We found that some hypermethylated genes in breast cancer were not expressed in breast tissues. RT-PCR assay showed that WT1 and PITX2 were only weakly expressed in the breast tumor tissues and weren’t expressed in most non-tumor breast tissues. OTX2 and PAX6 weren’t expressed in both breast tumor tissues and non-tumor tissues.
2011-11-11 | GSE33445 | GEO
Project description:To screen candidate methylation markers for early detection of breast cancer, we performed methylated-CpG island recovery assay combined with CpG island array on 61982 CpG sites across 4162 genes in 10 breast tumor tissues and 10 non-tumor breast tissues. We detected 70 significantly hypermethylated genes in breast tumor tissues, including many novel hypermethylated genes such as ITGA4, NFIX, OTX2 and FGF12. Direct bisulfite sequencing showed widespread methylations occurred in intragenic regions of WT1, PAX6 and ITGA4 genes and promoter region of OTX2 in breast cancer tissue. COBRA assay in independent tumor and non-tumor samples confirmed that WT1, OTX2 and PAX6 genes were hypermethylated in breast cancer tissues. To explore the relationship between methylation and gene expression, gene expression profiling analysis was performed in 8 breast tumor tissues and 8 non-tumor breast tissues. We found that some hypermethylated genes in breast cancer were not expressed in breast tissues. RT-PCR assay showed that WT1 and PITX2 were only weakly expressed in the breast tumor tissues and weren’t expressed in most non-tumor breast tissues. OTX2 and PAX6 weren’t expressed in both breast tumor tissues and non-tumor tissues. Unpaired experiments, breast tumor tissues vs. breast non-tumor tissues. Biological replicates: 8 breast cancer tissue replicates, 8 breast non-tumor tissue replicates.
2011-11-11 | E-GEOD-33447 | biostudies-arrayexpress