Unknown,Transcriptomics,Genomics,Proteomics

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Expression data from Tet2-hypomorph (knockdown) and/or Ezh2-null Lineage-Sca-1+c-Kit+ (LSK) cells and granulocyte-macrophage progenitors (GMPs)

ABSTRACT: PcG proteins form the polycomb repressive complexes (PRC) 1 and 2, functioning as transcriptional repressors through histone modifications. They have been implicated in the maintenance of self-renewing somatic and cancer stem cells. PcG genes have been characterized as tumor suppressor genes as exemplified by somatic inactivating mutations of EZH2, a gene encoding histone methyltransferase in PRC2, in myeloid malignancy. Mice deficient for Tet2 have been reported to recapitulate some aspects of myeloid malignancies. We evaluated the Ezh2-deficient mice and also tested the impact of concurrent depletion of Ezh2 and Tet2 on hematopoiesis. Purified LSK cells and GMPs from BM of recipient mice repopulated with wild-type, Tet2KD/KD, Ezh2-/- and Tet2KD/KDEzh2-/- fetal liver cells were subjected to RNA extraction and hybridization on Agilent microarrays.

ORGANISM(S): Mus musculus

SUBMITTER: ATSUSHI IWAMA

PROVIDER: E-GEOD-42666 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Cellular differentiation and lineage commitment are considered to be robust and irreversible processes during development. Recent work has shown that mouse and human fibroblasts can be reprogrammed to a pluripotent state with a combination of four transcription factors. This raised the question of whether transcription factors could directly specify somatic cell fates in cells such as pancreatic ? cells, contractile cardiomyocytes and neurons. We hypothesized that combinatorial expression of chondrocyte-specific transcription factors could directly convert human amnion cells into chondrosarcoma. Starting from a pool of candidate genes, we identified a combination of only five genes (5F pool), BCL6, T (also called BRACHYURY), c-MYC, MITF and BAF60C (also called SMARCD3) that rapidly and efficiently convert postnatal human amnion into chondrosarcoma. The cells generated expressed multiple cartilage-specific genes such as collagen type II ?1, link protein-1 and aggrecan, and exhibited characteristics of cartilage both in vivo and in vitro. Expression of the endogenous genes for T and MITF was initiated, implying that the cell conversion is due to not only the forced expression of the transgenes, but also the cellular reprogramming by the transgenes. The same set of genes converted human placental artery-derived endothelial (hPAE) cells and menstrual blood-derived cells into chondrosarcoma cells, implying that this conversion is independent of cell types. Direct conversion system from non-cartilage tissue to cartilaginous tissue contributes substantially to a major advance toward cartilage development, oncogenesis of chondrocytes, and cell-based therapy. We hypothesized that combinatorial expression of chondrocyte-specific transcription factors could directly convert human amnion cells into chondrosarcoma. Starting from a pool of candidate genes, we identified a combination of only five genes that rapidly efficiently convert postnatal human amnion into chondrosarcoma.

Project description:TET2 is a close relative of TET1, an enzyme that converts 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) in DNA. The gene encoding TET2 resides at chromosome 4q24, in a region showing recurrent microdeletions and copy-neutral loss of heterozygosity (CN-LOH) in patients with diverse myeloid malignancies. Somatic TET2 mutations are frequently observed in myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN), MDS/MPN overlap syndromes including chronic myelomonocytic leukaemia (CMML), acute myeloid leukaemias (AML) and secondary AML (sAML). We show here that TET2 mutations associated with myeloid malignancies compromise catalytic activity. Bone marrow samples from patients with TET2 mutations displayed uniformly low levels of 5hmC in genomic DNA compared to bone marrow samples from healthy controls. Moreover, small hairpin RNA (shRNA)-mediated depletion of Tet2 in mouse haematopoietic precursors skewed their differentiation towards monocyte/macrophage lineages in culture. There was no significant difference in DNA methylation between bone marrow samples from patients with high 5hmC versus healthy controls, but samples from patients with low 5hmC showed hypomethylation relative to controls at the majority of differentially methylated CpG sites. Our results demonstrate that Tet2 is important for normal myelopoiesis, and suggest that disruption of TET2 enzymatic activity favours myeloid tumorigenesis. Measurement of 5hmC levels in myeloid malignancies may prove valuable as a diagnostic and prognostic tool, to tailor therapies and assess responses to anticancer drugs. Genome wide DNA methylation profiling of patients samples with various myeloid malignancies and diffrential levels of 5hmC.The Illumina Infinium 27k Human DNA methylation Beadchip v1.2 was used to obtain DNA methylation profiles across approximately 27,000 CpGs in bone marrow samples and occasionally peripheral blood samples. Samples included 28 control healthy bone marrows, 29 patients samples with low 5hmC levels (7 patients with wild-type TET2 and 22 mutant TET2) and 24 with high levels of 5hmC (22 with wild-type TET2 and 2 mutant TET2). Bisulphite converted DNA from 81 samples was hybridised to the Illumina Infinium 27k Human Methylation Beadchip v1.2

Dataset Information

Expression data from Tet2-hypomorph (knockdown) and/or Ezh2-null Lineage-Sca-1+c-Kit+ (LSK) cells and granulocyte-macrophage progenitors (GMPs)

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