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)

We report a case of a psu dic(6;5)(p21.3;q13) in a patient with secondary myelodysplastic syndrome (sMDS) following treatment for multiple myeloma. The abnormal chromosome was isolated by flow karyotyping and initially identified by reverse chromosome painting. The findings were then confirmed by forward painting. The value of flow karyotyping as a diagnostic technique in hematologic malignancies is discussed.
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PMID:Characterization of psu dic(6;5)(p21.3;q13) with reverse chromosome painting in a patient with secondary myelodysplastic syndrome following treatment for multiple myeloma. 1469 41

The DNA methylation inhibitor 5-Aza-2'-deoxycytidine (5-Aza-CdR) has significant therapeutic value for the treatment of patients with myelodysplastic syndrome (MDS), acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). The demethylating effect of 5-Aza-CdR has been well characterized. In contrast, less is known about the molecular events downstream of the methylation inhibition. Here, 5-Aza-CdR induced apoptosis in AML cells (both p53 mutant and wild-type) but not in epithelial or normal PBMCs. Cell death was accompanied by activation of the mitochondrial apoptosis pathway, as shown by release of cytochrome c and AIF and loss of mitochondrial membrane potential (DeltaPsim). Activation of caspase-3 (but not -6 and -8) was detectable using Western blot analysis and measurement of caspase enzymatic activity. 5-Aza-CdR treatment resulted in the induction of p21, which correlated with the arrest of AML cells in the G1 cell cycle phase. Induction of p21 expression was independent of its promoter methylation status but mediated by 5-Aza-CdR-induced reexpression of the tumor-suppressor p73, a known upstream regulator of p21. The p73 promoter was hypermethylated in AML cell lines and in primary AML cells but not in epithelial cells, which were resistant toward 5-Aza-CdR. Therefore, 5-Aza-CdR-mediated specific killing of myeloid cells might be dependent on its ability to revert p73 promoter methylation and to reexpress p73 mRNA. In addition, exogenous expression of p73 rendered epithelial cells sensitive to apoptosis induced by 5-Aza-CdR or other cytostatic drugs. We therefore conclude that p73 is a relevant target for methylation-dependent efficacy of 5-Aza-CdR in AML cells.
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PMID:5-Aza-2'-deoxycytidine induces p21WAF expression by demethylation of p73 leading to p53-independent apoptosis in myeloid leukemia. 1560 9

Transcriptional silencing of tumour suppressor genes (TSG) due to hypermethylation is a common event in human tumours. The three members of the KIP/CIP family of cyclin dependent kinase inhibitors (CDKIs), p21(CIP 1), p27(KIP 1), and p 57(KIP 2), play key roles in cell cycle regulation, but little is known about their methylation in myeloid neoplasia. Therefore, we analysed 9 haematopoietic cell lines, 67 myelodysplastic syndrome (MDS) and 26 acute myeloid leukaemia (AML) cases as well as 11 controls. p 57(KIP 2) hypermethylation was found in 4/9 cell lines, but methylation of p21(CIP 1) and p27(KIP 1) was infrequent. All patient samples analysed were methylation-negative for these three genes.
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PMID:Absence of p21(CIP 1), p27(KIP 1) and p 57(KIP 2) methylation in MDS and AML. 1593 16

Myelodysplastic syndromes (MDS) represent a group of clonal hematopoietic disorders characterized by dyshemopoiesis and frequent evolution to acute leukemia. Tumor suppressor gene inactivation may be involved in MDS pathogenesis. The two families of cyclin-dependent kinase inhibitors (CDKIs) (INK4 family of p15, p16, p18 and p19 and CIP/KIP family of p21, p27 and p57) that negatively regulate cell cycle progression are known tumor suppressor genes. To determine whether genetic alterations of p16 and p27 genes play an important role in MDS pathogenesis, we examined DNA from 51 patients classified as 17 refractory anemias (RA), four refractory anemias with ringed sideroblasts (RARS), 19 refractory anemias with an excess of blasts (RAEB), 5 refractory anemias with excess of blasts in transformation (RAEB-t) and 6 chronic myelomonocytic leukemias (CMML). Southern blot analysis detected no homozygous deletions of p16 and p27. Polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) and sequencing did not reveal point mutations for both genes with the exception of two allelic polymorphisms, namely a C --> G transition at 447 bp of p16exon3 and a T --> A transition at 791 bp of p27exon1 genes. Our results suggest that mutations of p16 and p27 genes resulting in abnormal p16 and p27 proteins do not represent a mechanism of gene inactivation involved in the pathogenesis of MDS.
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PMID:Absence of p16 and p27 gene rearrangements and mutations in de novo myelodysplastic syndromes. 1610 74

In contrast to the well-documented involvement of EVI1 in various 3q26 aberrations, the transcriptional status of EVI1 in rare recurrent or sporadic 3q26 chromosomal defects has remained largely unexplored. Moreover, in a recent report, the association between 3q26 alterations in myeloid proliferations and ectopic EVI1 expression was questioned. Therefore, we performed a detailed physical mapping of 3q26 breakpoints using a 1.3-Mb tiling path BAC contig covering the EVI1 locus and a carefully designed quantification of both EVI1 and MDS/EVI1 transcripts in 30 hematological malignancies displaying 3q26 aberrations. Cases included well-known rare, recurring chromosomal aberrations such as t(3;17)(q26;q22), t(2;3)(p21-22;q26), and t(3;6)(q26;q25), as well as 10 new sporadic cases. Extensive 3q26 breakpoint mapping allowed unequivocal and sensitive FISH detection of EVI1 rearrangements on both metaphases and interphase nuclei. Real-time quantitative PCR analyses indicated that typically both MDS1/EVI1 and EVI1, but not MDS1, were expressed in these malignancies, with EVI1 the primary transcript. In conclusion, we have demonstrated EVI1 involvement in numerous novel sporadic and recurrent 3q26 rearrangements. Our results underscore the feasibility of FISH as an adjunct to PCR for the identification of EVI1 deranged leukemias and identified EVI1 as the principal transcript expressed in these malignancies.
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PMID:EVI1 is consistently expressed as principal transcript in common and rare recurrent 3q26 rearrangements. 1634 72

Myelodysplastic syndrome (MDS) with erythroid hypoplasia, a rare form of MDS, has not yet been clearly defined. We report here a 20-year-old woman with severe transfusion-dependent anemia and reticulocytopenia. White blood cells and platelet counts were normal. Bone marrow examination showed a low percentage of erythroid precursors (6%) and a marked dyserythropoiesis and dysmegakaryopoiesis. A diagnosis of MDS (refractory anemia according to the FAB classification) with erythroid hypoplasia was made. Cytogenetic analysis of the bone marrow and peripheral blood revealed a 46,XX,t(3;14)(p21.1;q24.1) translocation, which was confirmed by fluorescence in situ hybridization analysis. This translocation was detected in the apparently healthy younger brother, father, and aunt (father's sister) of the patient. Clonality of T cells in the patient was not confirmed by the polymerase chain reaction and heteroduplex temperature-gradient gel electrophoresis. IgM serology for B19 parvovirus was negative. Other conditions known to be associated with erythroid hypoplasia, such as thymoma, were not present. The patient failed to respond to immunosuppressive therapy (antithymocyte globulin and cyclosporin A). Administration of recombinant human erythropoietin improved her anemia. To our knowledge, this balanced translocation, namely t(3;14)(p21.1;q24.1), which is present both in the patient with MDS with erythroid hypoplasia and in the healthy members of the family, has not been defined previously.
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PMID:A case of myelodysplastic syndrome with erythroid hypoplasia associated with a familial translocation t(3;14)(p21.1;q24.1). 1688 88

Decitabine (DAC) and 5-azacitidine have recently been approved for the treatment of myelodysplastic syndrome. The pharmacodynamic effects of DAC and 5-azacitidine outside their known activity as inhibitors of DNA methyltransferases (DNMTs) require further investigation. The purpose of this study was to investigate the effect of DAC on the expression of p21(WAF1/CIP1), a gene with a putative CpG island surrounding its promoter region. Promoter methylation analysis of p21(WAF1/CIP1) in leukemia cells revealed the absence of CpG methylation. However, DAC upregulated p21(WAF1/CIP1) expression in a dose-dependent manner (ED(50)=103.34 nM) and induced G2/M cell cycle arrest in leukemia cells. Sequential application of DAC followed by different histone deacetylase inhibitors induced expression of p21(WAF1/CIP1) synergistically. Upregulation of p21(WAF1/CIP1) paralleled DAC-induced apoptosis (ED(50)=153 nM). Low doses of DAC induced gamma-H2AX expression (ED(50)=16.5 nM) and upregulated p21(WAF1/CIP1) in congenic HCT 116 colon cancer cells in a DNMT-independent and p53-dependent fashion. Inhibition of p53 transactivation by pifithrin-alpha or the kinase activity of ATM by either the specific ATM inhibitor KU-5593 or caffeine abrogated p21(WAF1/CIP1) upregulation, indicating that DAC upregulation of p21(WAF1/CIP1) was p53- and ATM-dependent in leukemia cells. In conclusion, DAC upregulates p21(WAF1/CIP1) in DNMT-independent manner via the DNA damage/ATM/p53 axis.
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PMID:p21(WAF1/CIP1) induction by 5-azacytosine nucleosides requires DNA damage. 1822 91

Most chromosomal translocations in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) involve oncogenes that are either up-regulated or form part of new chimeric genes. The t(2;11)(p21;q23) translocation has been cloned in 19 cases of MDS and AML. In addition to this, we have shown that this translocation is associated with a strong up-regulation of miR-125b (from 6- to 90-fold). In vitro experiments revealed that miR-125b was able to interfere with primary human CD34(+) cell differentiation, and also inhibited terminal (monocytic and granulocytic) differentiation in HL60 and NB4 leukemic cell lines. Therefore, miR-125b up-regulation may represent a new mechanism of myeloid cell transformation, and myeloid neoplasms carrying the t(2;11) translocation define a new clinicopathological entity.
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PMID:Myeloid cell differentiation arrest by miR-125b-1 in myelodysplastic syndrome and acute myeloid leukemia with the t(2;11)(p21;q23) translocation. 1893 36

The purpose of this study was to evaluate the expression of cyclin A1 mRNA in patients with myelodysplastic syndrome (MDS) and its clinical significance. The expression of cyclin A1, cdk2 and p21(cip1) mRNA in the bone marrow from 56 patients with MDS and 10 normal control were measured by using reverse transcription polymerase chain reaction (RT-PCR) technique. The results indicated that the positive rate and the expression level of cyclin A1 in MDS patients (69.64%; 0.964 +/- 1.879) were significantly higher than those in normal control (0%; 0.012 +/- 0.014) (p < 0.01). Among de-novo MDS patients, the expression level of cyclin A1 mRNA in the MDS-RAEB group (1.895 +/- 1.769) was higher than that in MDS-RA group (0.629 +/- 1.583) (p < 0.01). The expression level of cyclin A1 mRNA in post-treatment group was significantly lower than that in prior-treatment group (p < 0.01). It is concluded that the mRNA expression of cyclin A1 in MDS patients is higher than that in normal control, the abnormal expression of cyclin A1 may be used as a prognostic marker in MDS patients.
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PMID:[Expression of cyclin A1 mRNA in patients with myelodysplastic syndrome and its clinical significance]. 1937 70

Because DNA methyltransferase (DNMT) inhibitors like azacytidine and decitabine are known to be effective in the clinic for diseases like myelodysplastic syndromes that may result in part from transcriptional dysregulation due to epigenetic changes, there is interest in developing novel DNMT inhibitors that would be more effective and less toxic. The effects of one such agent, zebularine, which inhibits DNMT and cytidine deaminase, were assessed in two human breast cancer cell lines, MDA-MB-231 and MCF-7. Zebularine treatment inhibited cell growth in a dose and time dependent manner with an IC-50 of approximately 100 microM and 150 microM in MDA-MB-231 and MCF-7 cells, respectively, on 96 h exposure. This was associated with increased expression of p21, decreased expression of cyclin-D, and induction of S-phase arrest. At high doses zebularine induced changes in apoptotic proteins in a cell line specific manner manifested by alteration in caspase-3, Bax, Bcl2 and PARP cleavage. Like other DNMT inhibitors, zebularine decreased expression of DNMTs post-transcriptionally as well as expression of other epigenetic regulators like methyl CpG binding proteins and global acetyl H3 and H4 protein levels. Its capacity to reexpress epigenetically silenced genes in human breast cancer cells at low doses was confirmed by its ability to induce expression of estrogen and progesterone receptor mRNA in association with changes suggestive of active chromatin at the ER promoter as evidenced by ChIP. Finally, its effect in combination with other DNMT or HDAC inhibitors like decitabine or vorinostat was explored. The combination of 50 muM zebularine with decitabine or vorinostat significantly inhibited cell proliferation and colony formation in MDA-MB-231 cells compared with either drug alone. These findings suggest that zebularine is an effective DNMT inhibitor and demethylating agent in human breast cancer cell lines and potentiates the effects of other epigenetic therapeutics like decitabine and vorinostat.
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PMID:Effects of a novel DNA methyltransferase inhibitor zebularine on human breast cancer cells. 1945 41


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