ABSTRACT: Pediatric rhabdoid tumors of kidney and brain show many differences in gene expression but share dysregulation of cell cycle and epigenetic effector genes
Project description:Pediatric rhabdoid tumors of kidney and brain show many differences in gene expression but share dysregulation of cell cycle and epigenetic effector genes
Project description:Rhabdoid tumors (RTs) are aggressive tumors of early childhood that occur most often in brain (AT/RTs) or kidney (KRTs). Regardless of location, they are characterized by loss of functional SMARCB1 protein, a component of the SWI/SNF chromatin remodeling complex. The aim of this study was to determine genes and biological process dysregulated in common to both AT/RTs and KRTs. Gene expression for AT/RTs was compared to that of other brain tumors and normal brain using microarray data from our lab. Similar analysis was performed for KRTs and other kidney tumors and normal kidney using data from GEO. Dysregulated genes common to both analyses were analyzed for functional significance. Unsupervised hierarchical clustering of RTs identified 3 major subsets: 2 comprised of AT/RTs, and 1 of KRTs. Compared to other tumors, 1187, 663 and 539 genes were dysregulated in each subset, respectively. Only 14 dysregulated genes were common to all 3 subsets. Compared to normal tissue, 5209, 4275 and 2841 genes were dysregulated in each subset, with an overlap of 610 dysregulated genes. Among these genes, processes associated with cell proliferation, MYC activation, and epigenetic dysregulation were common to all 3 RT subsets. The low overlap of dysregulated genes in AT/RTs and KRTs suggests that factors in addition to SMARCB1 loss play a role in determining subsequent gene expression. Drugs which target cell cycle or epigenetic genes may be useful in all RTs. Additionally, targeted therapies tailored to specific RT subset molecular profiles should be considered. Molecular profiling of 20 ATRTs, 42 other pediatric CNS WHO Grade IV tumor samples and 9 pediatric normal brain samples was performed using Affymetrix U133 Plus2 GeneChips. Data were background corrected and normalized using gcRMA (as implemented in Bioconductor). ANOVA was used to identify differentially expressed genes for AT/RTs compared to other brain tumor types. Various analyses, including bioinformatics tools DAVID, Gene Set Enrichment (GSEA), and Ingenuity Pathways Analysis, were used to identify biological processes and genes of particular interest among the differentially expressed genes. Similar analysis of publicly available KRT and pediatric kidney tumor and normal kidney data was also performed by us. The overlaps between the results were examined to determine genes and processes dysregulated in common to both ATRTs and KRTs. This study includes a re-analysis of samples from other studies (AT/RT: GSE28026; glioblastoma: GSE33331).
Project description:Epigenetic dysregulation is a universal feature of cancer that results in altered patterns of gene expression that drive malignancy. Brain tumors exhibit subtype-specific epigenetic alterations, however the molecular mechanisms responsible for these diverse epigenetic states remain unclear. Here we show that the developmental transcription factor Sox9 differentially regulates epigenomic states in high-grade glioma (HGG) and ependymoma (EPN). These contrasting roles for Sox9 correspond with protein interactions with histone deacetylating complexes in HGG, and association with the Rela oncofusion in EPN. Together, our studies demonstrate how epigenomic states are differentially regulated in distinct subtypes of brain tumors, while revealing divergent roles for Sox9 in HGG and EPN tumorigenesis.
Project description:Wilms tumors are pediatric cancers thought to arise from kidney-specific stem cells. In order to identify transcriptional and epigenetic mechanisms that drive these malignant cells, we compared genomewide chromatin profiles of Wilms tumors to embryonic stem (ES) cells and normal kidney. Data represent examination of genome-wide chromatin modifications in primary Wilms tumors, fetal and mature kidney.
Project description:Wilms tumors are pediatric cancers thought to arise from kidney-specific stem cells. In order to identify transcriptional and epigenetic mechanisms that drive these malignant cells, we compared genomewide chromatin profiles of Wilms tumors to embryonic stem (ES) cells and normal kidney.
Project description:Rhabdoid tumors (RTs) are aggressive tumors of early childhood that occur most often in brain (AT/RTs) or kidney (KRTs). Regardless of location, they are characterized by loss of functional SMARCB1 protein, a component of the SWI/SNF chromatin remodeling complex. The aim of this study was to determine genes and biological process dysregulated in common to both AT/RTs and KRTs. Gene expression for AT/RTs was compared to that of other brain tumors and normal brain using microarray data from our lab. Similar analysis was performed for KRTs and other kidney tumors and normal kidney using data from GEO. Dysregulated genes common to both analyses were analyzed for functional significance. Unsupervised hierarchical clustering of RTs identified 3 major subsets: 2 comprised of AT/RTs, and 1 of KRTs. Compared to other tumors, 1187, 663 and 539 genes were dysregulated in each subset, respectively. Only 14 dysregulated genes were common to all 3 subsets. Compared to normal tissue, 5209, 4275 and 2841 genes were dysregulated in each subset, with an overlap of 610 dysregulated genes. Among these genes, processes associated with cell proliferation, MYC activation, and epigenetic dysregulation were common to all 3 RT subsets. The low overlap of dysregulated genes in AT/RTs and KRTs suggests that factors in addition to SMARCB1 loss play a role in determining subsequent gene expression. Drugs which target cell cycle or epigenetic genes may be useful in all RTs. Additionally, targeted therapies tailored to specific RT subset molecular profiles should be considered.
Project description:We performed gene expression profiling on 151 paraffin-embedded PLGGs from different locations, ages, histological subtypes as well as BRAF genetic status We also compared molecular differences to normal pediatric brain expression profiles to observe whether those patterns were mirrored in normal brain expression. We analyzed the expression of 6,100 genes among 151 FFPE pediatric and 15 FFPE adult low-grade gliomas and analyzed how the expression patterns changes with location, age, histology and BRAF genomic status and how those differences were mirrored in normal brain expression. The values in the sample 'characteristics' columns represent; Location; SUP= Supratentorial, INF= Infratentorial Histology; PA= pilocytic astrocytoma, GG= ganglioglioma, DNT= dysembryoplastic neuroepithelial tumor, OD= oligodendroglial tumors, NOS= not otherwise specified tumors BRAF status; DUP= BRAF duplication, MUT= BRAF V600E mutation, WT= wild type, ND= not determined Primary or recurrent tumor; P=primary, R=recurrent Primary tumor that further progressed; 1=yes, 0=no, _=recurrent tumors only
Project description:Epidemiological studies indicate that adverse intrauterine and postnatal environment has a long-lasting role in chronic kidney disease (CKD) development. Epigenetic information can represent a plausible carrier for mediating this programming effect. Here we demonstrate that genome-wide cytosine methylation patterns of healthy and CKD tubule samples obtained from patients show significant differences. Cytosine methylation changes showed high concordance (98%) with a large (n=87) replication dataset. We rarely observed differentially methylated regions (DMR) on promoters. Histone modification-based kidney specific genome-wide gene regulatory region annotation maps (promoters, enhancers, transcribed and repressed regions) were generated. DMRs mostly overlapped with putative enhancer regions and were enriched in consensus binding sequences for important renal transcription factors, indicating their importance in gene expression regulation. A core set of genes, including transforming growth factors and collagens, showed cytosine methylation changes correlating with downstream transcript levels. Our report raises the possibility that epigenetic dysregulation plays a role in CKD development via influencing core profibrotic pathways. We used microarrays to detail the differences of gene expression of human tubule epithelial cells between chronic kidney disease and normal. We sought to decrease the cell type heterogeneity of kidney tissues to increase the resolution of expression profiles. To that end, microdissected human kidney tissue from both chronic kidney disease patient and normal are used for RNA extraction and hybridization on Affymetrix microarrays.
Project description:Epidemiological studies indicate that adverse intrauterine and postnatal environment has a long-lasting role in chronic kidney disease (CKD) development. Epigenetic information can represent a plausible carrier for mediating this "programming" effect. Here we demonstrate that genome-wide cytosine methylation patterns of healthy and CKD tubule samples obtained from patients show significant differences. We rarely observed differentially methylated regions (DMR) on promoters. Histone modification-based kidney specific genome-wide gene regulatory region annotation maps (promoters, enhancers, transcribed and repressed regions) were generated. DMRs mostly overlapped with putative enhancer regions and were enriched in consensus binding sequences for important renal transcription factors, indicating their importance in gene expression regulation. A core set of genes, including transforming growth factors and collagens, showed cytosine methylation changes correlating with downstream transcript levels. Our report raises the possibility that epigenetic dysregulation plays a role in CKD development via influencing core profibrotic pathways. HG18_HELP array We used custom-commercial array to detail the differences of methylation regions of human tubule epithelial cells between chronic kidney disease and normal. We sought to decrease the cell type heterogeneity of kidney tissues to increase the resolution of methylation profiles. To that end, microdissected human kidney tissue from both chronic kidney disease patient and normal are used for the HELP-assay (HpaII tiny fragment Enrichment by Ligation-mediated PCR) and hybridization on Roche NimbleGen microarrays.