Project description:Posterior fossa A (PFA) ependymomas comprise one out of nine molecular groups of ependymoma. PFA tumors are mainly diagnosed in infants and young children, show a poor prognosis and are characterized by a lack of the repressive histone H3 lysine 27 trimethylation (H3K27me3) mark. Recently, we reported CXorf67 overexpression as hallmark of PFA ependymoma and showed that CXorf67 can interact with EZH2 thereby inhibiting polycomb repressive complex 2 (PRC2). Here, we report that the inhibitory mechanism of this interaction is similar as in diffuse midline gliomas harboring H3K27M mutations. A small, highly conserved peptide sequence located in the C-terminal region of CXorf67 mimics the H3K27M peptide and binds to the SET domain of EZH2. This interaction blocks EZH2 methyltransferase activity and causes H3K27 hypomethylation, an oncogenic mechanism that may be exploited for targeted therapy in PFA ependymoma. Based on its function, we have renamed CXorf67 into EZH2 Inhibitory Protein (EZHIP).
Project description:Upregulation of enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) and its associated histone H3 lysine 27 (H3K27) trimethylation frequently occur in human cancer, yet both preclinical and clinical evidence suggested the very limited benefit of EZH2-targeted therapies. This study investigated the underlying mechanisms from a perspective of EZH2 inhibition-caused histone modification crosstalk. A mass spectrometry approach enabled us discovering the alteration of global histone modifications responding to EZH2 inhibition. Feedback upregulation of H3K27 acetylation (H3K27ac) level is closely associated with limited drug response to EZH2 inhibition across multiple cancer types. H3K27ac alteration caused transcriptional activation of oncoproteins confers drug resistant to EZH2 inhibition. Here we used ChIP-Seq analysis to identify the alteration of genome-wide H3K27ac bingding sites with EZH2 inhibitor treatment in human cancer cell lines.
Project description:Polycomb group (PcG) proteins including EZH2, SUZ12 and so on, which specifically catalyze trimethylation of histone 3 lysine 27 (H3K27me3), and methylated H3K27 can be recognized by other specific binding proteins to compress chromatin structure, leading to the transcriptional repression of the target genes. To completely understand the epigenetic profile and molecular network of PcG in HCC, we performed ChIP-on-chip screens with EZH2, SUZ12 and H3K27me3 antibodies in HepG2 cells. Comparison of ChIP-on-chip results from EZH2, SUZ12 and H3K27me3.
Project description:Enhancer of Zeste Homolog 2 (EZH2) is a histone methyltransferase that catalyzes the trimethylation of histone H3 lysine 27 (H3K27me3). EZH2 expression is significantly upregulated in MPNST. In our study, we investigated the function of EZH2 and the molecular mechanisms that are regulated by EZH2 in MPNST pathogenesis. Our findings enhance the knowledge of EZH2’s function and biology, and have the potential to provide a novel therapeutic approach for MPNST patients in the clinic.
Project description:Enhancer of Zeste Homolog 2 (EZH2) is a histone methyltransferase that catalyzes the trimethylation of histone H3 lysine 27 (H3K27me3). EZH2 expression is significantly upregulated in MPNST. In our study, we investigated the function of EZH2 and the molecular mechanisms that are regulated by EZH2 in MPNST pathogenesis. Our findings enhance the knowledge of EZH2’s function and biology, and have the potential to provide a novel therapeutic approach for MPNST patients in the clinic.
Project description:Normal cell type specific histone H3 lysine 27 trimethylation of miRNA genes. HMEC and HMF represent two distinct differentiated cell type present in mammary gland each with a distinct phenotype, a distinct epigenotype as well as distinct miRNA expression pattern. The aim of the study was to determine how epigenetic modifications including histone H3 lysine 27 trimethylation affect miRNA expression. Two cell types HMEC vs. HMF. Biological replicates: 3 pairs of HMEC-HMF of 3 distinct genotypes. Immunoprecipitation using anti-histone H3 trimethylated at lysine 27 (07-449, Millipore).
Project description:This SuperSeries is composed of the following subset Series: GSE28374: DNA methylation of miRNA genes in HMEC and HMF GSE28375: Histone H3 acetylation of miRNA genes in HMEC and HMF GSE28376: Histone H3 lysine 27 trimethylation of miRNA genes in HMEC and HMF GSE28377: Histone H3 lysine 4 trimethylation of miRNA genes in HMEC and HMF GSE28378: Histone H3 lysine 9 dimethylation of miRNA genes in HMEC and HMF Refer to individual Series
Project description:Recurrent somatic ASXL1 mutations occur in patients with myelodysplasia (MDS), myeloproliferative neoplasms (MPN), and acute myeloid leukemia (AML), and are associated with adverse outcome. Despite the genetic and clinical data implicating ASXL1 mutations in myeloid malignancies, the mechanisms of transformation by ASXL1 mutations are not understood. Here we identify that ASXL1 mutations result in loss of PRC2-mediated histone H3 lysine 27 (H3K27) tri-methylation. Through integration of microarray data with genome-wide histone modification ChIP-Seq data we identify targets of ASXL1 repression including the posterior HOXA cluster that is known to contribute to myeloid transformation. We demonstrate that ASXL1 associates with the Polycomb repressive complex 2 (PRC2), and that loss of ASXL1 in vivo collaborates with NRASG12D to promote myeloid leukemogenesis. To assess the genome-wide effects of ASXL1 loss on chromatin state we performed chromatin immunoprecipitation followed by next generation sequencing (CHIP-seq) for histone modifications known to be associated with PcG (histone H3 lysine 27 trimethylation (H3K27me3)) or TxG activity (histone H3 lysine 4 trimethylation (H3K4me3)) in UKE1 cells expressing empty vector (EV) or 2 independent validated shRNAs for ASXL1. This Series represents the ChIP-Seq data (not the microarray data referenced in the summary above). The related micorarray data are available in GEO as GSE38692.
Project description:Enhancer of Zeste Homolog 2 (EZH2) is a histone methyltransferase that catalyzes the trimethylation of histone H3 lysine 27 (H3K27me3). EZH2 expression is significantly upregulated in MPNST. In our study, we investigated the function of EZH2 and the molecular mechanisms that are regulated by EZH2 in MPNST pathogenesis. Our findings enhance the knowledge of EZH2’s function and biology, and have the potential to provide a novel therapeutic approach for MPNST patients in the clinic. An EZH2 knockdown experiment was carried out in MPNST cells. There are one control and one siEZH2 samples for three cell lines (724,462,26T) and two repeats for each cell line, so in total there are 8 samples. Two group comparison Two group comparison
Project description:Enhancer of Zeste Homolog 2 (EZH2) is a histone methyltransferase that catalyzes the trimethylation of histone H3 lysine 27 (H3K27me3). EZH2 expression is significantly upregulated in MPNST. In our study, we investigated the function of EZH2 and the molecular mechanisms that are regulated by EZH2 in MPNST pathogenesis. Our findings enhance the knowledge of EZH2’s function and biology, and have the potential to provide a novel therapeutic approach for MPNST patients in the clinic. An EZH2 knockdown experiment was carried out in MPNST cells. There are one control and one siEZH2 samples for two cell lines (724 and 462) and two repeats for each cell line, so in total there are 8 samples. Two group comparison