Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The transcription factor ecotropic viral integration site 1 (Evi1) is associated with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) in patients due to chromosomal aberration of chromosome 3. Here we show that Evi1 interacts with the histone methyltransferase SUV39H1. The interaction requires the N-terminal part of Evi1 and the H3-specific histone methyltransferase domain, SET, of SUV39H1 without Evi1 having an inhibitory effect on SUV39H1 methyltransferase activity. Presence of SUV39H1 enhances Evi1 transcriptional repression in a dose dependent manner. In addition, Evi1 also interacts with another histone methyltransferase, G9a, but not with SET9. Our data establish an epigenetic role of Evi1 in cell transformation by recruiting higher order chromatin remodeling complexes.
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PMID:A novel interaction between the proto-oncogene Evi1 and histone methyltransferases, SUV39H1 and G9a. 1861 62

EVI1 is an oncoprotein inappropriately expressed in acute myeloid leukemia and myelodysplastic syndrome cells. In vitro studies indicate that diverse biological properties can be attributed to this protein. Its role in leukemogenesis is still unclear but it is thought that overall EVI1 can act mostly as a transcription repressor through its interaction with a subset of histone deacetylases. Studies with histone deacetylase inhibitors have however indicated that EVI1-mediated repression can be only partially rescued by deacetylase inhibitor drugs, suggesting that additional chromosomal modifications might occur to induce gene repression by EVI1. To investigate whether histone methylation contributes to the repressive potential of EVI1, we examined a potential association between EVI1, the histone methyltransferase (HMT) SUV39H1, and methyltransferase activity in vitro. We find that EVI1 directly interacts with SUV39H1 and that the proteins form an active complex with methyltransferase activity in vitro. Our data indicate that SUV39H1 enhances the transcription repressive potential of EVI1 in vivo. We suggest that EVI1 affects promoters' activity in two different pathways, by association with histone deacetylases and by recruiting chromatin-modifying enzymes to impose a heterochromatin-like structure establishing a lasting transcription repression.
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PMID:EVI1 recruits the histone methyltransferase SUV39H1 for transcription repression. 1865 52

In myelodysplastic syndromes (MDS), deletions of chromosome 7 or 7q are common and correlate with a poor prognosis. The relevant genes on chromosome 7 are unknown. We report here that EZH2, located at 7q36.1, is frequently targeted in MDS. Analysis of EZH2 deletions, missense and frameshift mutations strongly suggests that EZH2 is a tumor suppressor. As EZH2 functions as a histone methyltransferase, abnormal histone modification may contribute to epigenetic deregulation in MDS.
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PMID:Somatic mutations of the histone methyltransferase gene EZH2 in myelodysplastic syndromes. 2060 54

The myelodysplastic syndrome (MDS) is a group of heterogeneous clonal disorders. So far, the etiology and pathogenesis of MDS is poorly understood. Recently, more and more epigenetic regulator gene such as TET2, ASXL1, EZH2, DNMT3A and UTX mutations were detected in patients with MDS: TET2 may convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (hmC). TET2 is the most frequently mutated gene in MDS known so far and it may act as tumor-suppressor gene. ASXL1 belongs to the enhancer of trithorax and Polycomb (ETP) gene group. MDS phenotypes may be caused not only by loss-of-function of ASXL1 but also by gain-of-function mutations, overexpression of this gene and so on. EZH2 is a kind of histone methyltransferase. EZH2 is frequently over-expressed in a wide variety of cancerous tissue types, which reveals it has oncogenic activity. While, defined mutations resulted in dysfunction of histone methyltransferase activity, suggesting that EZH2 acts as a tumor suppressor for myeloid malignancies. DNMT3A belongs to the DNA methyltransferases (DNMT) gene family. It may be correlated with abnormal methylation status in patients with MDS. UTX coding protein is a histone demethylase, and UTX can affect cell proliferation as well as cell fate decision. Inactivating UTX mutations are found in multiple cancer types recently. These gene mutations may play key roles in the pathogenesis of MDS, which are summarized in this review.
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PMID:[An update on epigenetic regulator gene mutations and pathogenesis of myelodysplastic syndromes]. 2204 Sep 93

The polycomb repressive complex 2 (PRC2) is a highly conserved histone H3 lysine 27 methyltransferase that regulates the expression of developmental genes. Inactivating mutations of the catalytic component of PRC2, EZH2, are seen in myeloid disorders. We reasoned that the other 2 core PRC2 components, SUZ12 and EED, may also be mutational targets in these diseases, as well as associated factors such as JARID2. SUZ12 mutations were identified in 1 of 2 patients with myelodysplastic syndrome/myeloproliferative neoplasms with 17q acquired uniparental disomy and in 2 of 2 myelofibrosis cases with focal 17q11 deletions. All 3 were missense mutations affecting the highly conserved VEFS domain. Analysis of a further 146 myelodysplastic syndrome/myeloproliferative neoplasm patients revealed an additional VEFS domain mutant, yielding a total mutation frequency of 1.4% (2 of 148). We did not find mutations of JARID2 or EED in association with acquired uniparental disomy for chromosome 6p or 11q, respectively; however, screening unselected cases identified missense mutations in EED (1 of 148; 1%) and JARID2 (3 of 148; 2%). All 3 SUZ12 mutations tested and the EED mutation reduced PRC2 histone methyltransferase activity in vitro, demonstrating that PRC2 function may be compromised in myeloid disorders by mutation of distinct genes.
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PMID:Inactivation of polycomb repressive complex 2 components in myeloproliferative and myelodysplastic/myeloproliferative neoplasms. 2230 77

Different epigenetic alterations (DNA methylation, histone modifications, chromatin remodeling, noncoding RNA dysregulation) are associated with the phenotypic expression of complex disorders in which genomic, epigenomic, proteomic, and metabolomic changes, in conjunction with environmental factors, are involved. As epigenetic modifications are reversible and can be potentially targeted by pharmacological and dietary interventions, a series of epigenetic drugs have been developed, including DNA methyltransferase inhibitors (nucleoside analogs, small molecules, bioproducts, antisense oligonucleotides, miRNAs), histone deacetylase inhibitors (short-chain fatty acids, hydroxamic acids, cyclic peptides, benzamides, ketones, sirtuin inhibitors, sirtuin activators), histone acetyltransferase modulators, histone methyltransferase inhibitors, histone demethylase inhibitors, and noncoding RNAs (miRNAs), with potential effects against myelodysplastic syndromes, different types of cancer, and neurodegenerative disorders. Pharmacogenetic and pharmacoepigenetic studies are required for the proper evaluation of efficacy and safety issues in clinical trials with epigenetic drugs.
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PMID:Epigenomic networking in drug development: from pathogenic mechanisms to pharmacogenomics. 2519 79

Two of the most common myeloid malignancies, myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), are associated with exceedingly low survival rates despite recent therapeutic advances. While their etiology is not completely understood, evidence suggests that certain chromosomal abnormalities contribute to MDS and AML progression. Among the most frequent chromosomal abnormalities in these disorders are alterations of chromosome 7: either complete loss of one copy of chromosome 7 (-7) or partial deletion of 7q (del(7q)), both of which increase the risk of progression from MDS to AML and are associated with chemoresistance. Notably, 7q36.1, a critical minimally deleted region in 7q, includes the gene encoding the histone methyltransferase mixed-lineage leukemia 3 (MLL3), which is also mutated in a small percentage of AML patients. However, the mechanisms by which MLL3 loss contributes to malignancy are unknown. Using an engineered mouse model expressing a catalytically inactive form of Mll3, we found a significant shift in hematopoiesis toward the granulocyte/macrophage lineage, correlating with myeloid infiltration and enlargement of secondary lymphoid organs. Therefore, we propose that MLL3 loss in patients may contribute to the progression of MDS and AML by promoting myelopoiesis.
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PMID:Loss of Mll3 Catalytic Function Promotes Aberrant Myelopoiesis. 2761 Jun 19

Pediatric myelodysplastic syndrome (MDS) is an uncommon disease and little is known about the molecular alterations of its development and evolution to acute myeloid leukemia (AML). The Enhancer of Zeste Homolog 2 (EZH2) is the catalytic subunit of Polycomb repressive complex 2 (PCR2). It is a histone methyltransferase, that targets lysine 27 of histone 3. This methylated H3-K27 is usually associated with the silencing of genes that are involved in fundamental cellular processes, such as cell proliferation and differentiation. There are only few studies showing the status of EZH2 expression in patients with MDS and they were performed in adult MDS patients. The aim of this study was to analyze the EZH2 expression in pediatric patients with MDS and its association with karyotypes and evolution to acute myeloid leukemia (AML). We conducted the first study of EZH2 expression in pediatric patients with MDS. Considering the EZH2 expression levels in 42 patients and 17 healthy pediatric donors, it was possible to define three groups of expression in patients: low, intermediate, and high. The intermediate level encompassed patients with normal karyotypes, low level included patients with monosomy 7 and del(7q) and high level included patients with trisomy 8 and del(11q) (p < 0.0001). Comparing the leukemic evolution, the low expression group presented disease evolution in 100% (8/8) of the cases, the intermediate expression group showed disease evolution in 4.34% (1/23) and in the high expression group, 63.63% (7/11) patients showed evolution from MDS to AML (p < 0.0001). It is important to note that low and high EZH2 expression are associated with leukemic evolution, however low expression showed a stronger association with evolution from MDS to AML than the high expression. Our results suggest a scale of measure for EZH2 expression in pediatric MDS, where aberrant EZH2 expression may be a potential biomarker of disease evolution.
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PMID:Aberrant Expression of EZH2 in Pediatric Patients with Myelodysplastic Syndrome: A Potential Biomarker of Leukemic Evolution. 3188