Project description:Bromodomains have emerged as attractive candidates for the development of inhibitors targeting gene transcription. Inhibitors of the bromo-and-extra-terminal (BET) family recently showed promising activity in diverse disease models. However, the pleiotropic nature of BET proteins regulating tissue specific transcription has raised safety concerns and suggested that attempts should be made for domain-specific targeting. Here we report that RVX-208, a compound currently in phase II clinical trials, is a BET bromodomain inhibitor specific for second bromodomains (BD2). Co-crystal structures revealed binding modes of RVX-208 and its synthetic precursor and fluorescent recovery after photobleaching demonstrated that RVX-208 displaces BET proteins from chromatin. However, gene expression data showed that BD2 inhibition only modestly affects BET-dependent gene transcription. Our data demonstrate the feasibility of specific targeting within the BET family resulting in different transcriptional outcomes and highlight the importance of BD1 in transcriptional regulation HepG2 Cells were treated with eitther DMSO or 0.5uM JQ1 or 5uM RVX-208. Three samples per condition, total of nine samples. Inhbitor treatment was carried out for 4h before RNA was extracted. HepG2 cells (ATCC: HB-8065) were maintained in M-NM-1-MEM (Cat.#BE12-169F; BioWhittaker) supplemented with 10 % heat-inactivated foetal calf serum (PAA #A15-152), non-essential amino acids (Cat. #M7145; Sigma), glutamine (Cat.#M11-004; PAA), and vitamins (Cat.#M6895; Sigma). Cells were grown at 37 M-BM-0C in a humidified cabinet at 5 % CO2 (Heraeus Function Line). For experiments, cells were seeded the day prior to treatment at 2x105/ml. Treatments were performed for 4 h so that a final concentration of 0.1 % DMSO (Cat.#D1435; Sigma) was achieved. At harvest, cells were washed once with PBS (Cat.#H15-002; PAA), and lysed in situ using RLT buffer supplemented with 10 M-NM-<l/ml M-NM-2-mercaptoethanol (Cat.#M7522; Sigma). Total RNA was extracted and prepared using RNeasy columns (Cat.#74106 plus; Qiagen) including a Qia shredding step (Cat.#79656; Qiagen) and an on-column DNAse digestion (Cat.#EN0521; Fermentas), according to the manufacturerM-bM-^@M-^Ys instructions. The resulting RNA was quantified and quality controlled using a Nanodrop spectrophotometer (model ND1000; Thermo Fisher). RNA integrity was assessed on a BioAnalyzer (model G2938C; Agilent Laboratories, USA) and all samples had a RNA Integrity Number (RIN) M-bM-^IM-% 9. Labelled sense ssDNA for hybridization was generated from 200 ng starting RNA with the Ambion WT expression kit (Cat.#4411973; Ambion) and the Affymetrix GeneChip WT Terminal Labelling and Controls Kit (Cat.#901525; Affymetrix) according to the manufacturerM-bM-^@M-^Ys instructions. The distribution of fragmented sense ssDNA lengths was measured on the BioAnalyser. The fragmented ssDNA was labelled and hybridized for 17 hours at 45 M-BM-0C on the Affymetrix GeneChip Human Gene 1.0 ST Array (Affymetrix). Chips were processed on an Affymetrix GeneChip Fluidics Station 450 and Scanner 3000 and the affymetrix Command Console (v.3.2.4; Affymetrix) was used to generate CEL files.

Project description:The classical sacrococcygeal chordoma tumor presents with a typical morphology of lobulated myxoid tumor tissue with cords, strands and nests of tumor cells consisting of small non-vacuolated cells, intermediate cells with a wide range of vacuolization and large heavily vacuolated (physaliferous) cells. Because of its rare incidence, lack of suited model systems and technical limitations analysis was only performed on bulk tumor mass neglecting its heterogeneous composition. We aimed at elucidating the differences between small non-vacuolated and large physaliferous cells on the genomic and transcriptomic level. Secondly, we intended to clarify whether the observed cell types are derived from genetically distinct clones or rather represent different phenotypes. Using the chordoma cell line MUG-Chor1 we monitored morphological changes via time lapse experiments. We isolated pure fractions of each phenotype by means of laser microdissection or micromanipulation allowing phenotype-specific analysis. Pools of 100 cells each were genetically profiled after whole genome amplification by array comparative genomic hybridization. For expression analysis 20 cells each were subjected to whole transcriptom amplification, forwarded to RNA microarray analysis and qRT-PCR. Time lapse analysis unveiled small non-vacuolated cells to develop into large physaliferous cells via intermediate cells containing an increasing amount of vacuoles. Furthermore, we showed small and large physaliferous cells to proliferate at the same rate but intermediate cells to be the most proliferating cell phenotype. Small non-vacuolated and large physaliferous cells showed identical copy number variations. Despite their obvious morphological disparities we detected only modest changes in over all gene expression. However, verification of candidate genes yielded significant up-regulation of ALG11 (700-fold), PPP2CB (18.6-fold), and UCHL3 (18.7-fold) in large physaliferous cells. Of two different cell types (large and small MUG-Chor1 cells) we analysed each in triplicates. In total 6 cell pools were analysed.

Project description:Acute lymphoblastic leukemia (ALL), the commonest childhood malignancy, is characterized by recurring gross and submicroscopic structural genetic alterations that contribute to leukemogenesis. Disordered epigenetic regulation is a hallmark of many tumors, and while analysis of DNA methylation of limited numbers of genes or ALL samples suggests epigenetic alterations may also be important, a large-scale integrative genome-wide analysis evaluating DNA methylation in ALL has not been performed. Here, we report an integrated epigenomic, transcriptional and genetic analysis of 167 childhood ALL cases, comprising B-progenitor ALL with hyperdiploidy (N=26), ETV6-RUNX1 (N=27), TCF3-PBX1 (N=9), BCR-ABL1 (N=19), rearrangement of MLL (MLLr) (N=20), rearrangement of CRLF2 (N=11, CRLF2r), deletion of ERG (N=11), miscellaneous or normal karyotype (N=14), and T-lineage ALL (N=30), including 4 MLLr cases and 7 cases with early T-cell precursor immunophenotype. Genome-wide profiling of structural DNA alterations was performed for all cases using Affymetrix 500K and SNP 6.0 arrays. Affymetrix U133A gene expression profiling data was available for 154 cases [GEO Series GSE26281]. Genome-wide methylation profiling was performed using the HELP microarray assay, which measures methylation at approximately 50,000 CpGs distributed among 22,722 Refseq promoters. Methylation data was compared to that of normal pro-B (CD34+CD19+sIg-), pre-B (CD34-CD19+sIg-) and mature B (CD34-CD19+sIg+) cells FACS-sorted from bone marrow of 6 healthy individuals. Unsupervised hierarchical clustering of the top 4043 most variable methylation probesets identified 9 B-ALL clusters with significant correlation to specific genetic lesions including ETV6-RUNX1, MLLr, BCR-ABL1, CRLF2r, TCF3-PBX1 and ERG deletion. T-ALLs and hyperdiploid B-ALLs also defined specific DNA methylation clusters. Supervised analysis including limma and ANOVA identified distinct DNA methylation signatures for each subtype. Notably, the strength of these signatures was subtype dependent, with more differentially methylated genes observed in ALL cases with genetic alterations targeting transcriptional regulators (e.g. ETV6-RUNX1 and MLLr) and fewer genes in cases with alterations deregulating cytokine receptor signaling (e.g. CRLF2r). Aberrant DNA methylation affected specific and distinct biological processes in the various leukemia subtypes implicating epigenetic regulation of these pathways in the pathogenesis of these different forms of ALL (e.g. TGFB and TNF in ERG deleted leukemias; telomere and centriole regulation in BCR-ABL1 ALL). Aberrantly methylated genes were also enriched for binding sites of known or suspected oncogenic transcription factors that might represent cooperative influences in establishing the phenotype of the various B-ALL subtypes. Most importantly, an integrated analysis of methylation and gene expression of these ALL subtypes demonstrated striking inversely correlated expression of the corresponding gene transcripts. The methylation signatures of each subtype exhibited only partial overlap with those of normal B cells, indicating that the signatures do not simply reflect stage of lymphoid maturation. In a separate approach, we discovered that 81 genes showed consistent aberrant methylation across all ALL subtypes, including the tumor suppressor PDZD2, HOXA5, HOXA6 and MSH2. Inverse correlation with expression was confirmed in 66% of these genes. These data suggest the existence of a common epigenetic pathway underlying the malignant transformation of lymphoid precursor cells. Integrative genetic and epigenetic analysis revealed hypermethylation of genes on trisomic chromosomes that do not show increased expression, suggesting that epigenetic silencing may control genes within amplified regions and explain why only selected genes are overexpressed. Finally, analysis of individual genes targeted by recurring copy number alterations in ALL revealed a subset of genes also targeted by abnormal methylation, with corresponding changes in gene expression (e.g. ERG, GAB1), suggesting that such genes are inactivated far more frequently than suggested by genetic analyses alone. Collectively, the data support a key role of epigenetic gene regulation in the pathogenesis of ALL, and point towards a scenario where genetic and epigenetic lesions cooperatively determine disease phenotype. 186 samples were analyzed by DNA methylation on the HELP array, including 167 Diagnostic ALL samples and 19 Normal Bone Marrow B cells. There are no replicates

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Rapid reprogramming of epigenetic and transcriptional profiles in mammalian culture systems

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