Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023467 (acute myeloid leukemia)
 35,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Nuclear receptor-binding SET domain protein 1 (NSD1) prototype is a family of mammalian histone methyltransferases (NSD1, NSD2/MMSET/WHSC1, NSD3/WHSC1L1) that are essential in development and are mutated in human acute myeloid leukemia (AML), overgrowth syndromes, multiple myeloma and lung cancers. In AML, the recurring t(5;11)(q35;p15.5) translocation fuses NSD1 to nucleoporin-98 (NUP98). Here, we present the first characterization of the transforming properties and molecular mechanisms of NUP98-NSD1. We demonstrate that NUP98-NSD1 induces AML in vivo, sustains self-renewal of myeloid stem cells in vitro, and enforces expression of the HoxA7, HoxA9, HoxA10 and Meis1 proto-oncogenes. Mechanistically, NUP98-NSD1 binds genomic elements adjacent to HoxA7 and HoxA9, maintains histone H3 Lys 36 (H3K36) methylation and histone acetylation, and prevents EZH2-mediated transcriptional repression of the Hox-A locus during differentiation. Deletion of the NUP98 FG-repeat domain, or mutations in NSD1 that inactivate the H3K36 methyltransferase activity or that prevent binding of NUP98-NSD1 to the Hox-A locus precluded both Hox-A gene activation and myeloid progenitor immortalization. We propose that NUP98-NSD1 prevents EZH2-mediated repression of Hox-A locus genes by colocalizing H3K36 methylation and histone acetylation at regulatory DNA elements. This report is the first to link deregulated H3K36 methylation to tumorigenesis and to link NSD1 to transcriptional regulation of the Hox-A locus.
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PMID:NUP98-NSD1 links H3K36 methylation to Hox-A gene activation and leukaemogenesis. 1758 99

The combination of a DNA hypomethylating agent with a histone deacetylase inhibitor has synergistic antileukemia activity and may restore sensitivity to all-trans retinoic acid (ATRA). We conducted a phase 1/2 study of the combination of 5-azacitidine (5-AZA), valproic acid (VPA), and ATRA in patients with acute myeloid leukemia or high-risk myelodysplastic syndrome. 5-AZA was administered subcutaneously at a fixed dose of 75 mg/m(2) daily for 7 days. VPA was dose-escalated and given orally daily for 7 days concomitantly with 5-AZA. ATRA was given at 45 mg/m(2) orally daily for 5 days, starting on day 3. A total of 53 patients were treated. Their median age was 69 years (range, 5-84 years). The maximum tolerated dose of VPA in this combination was 50 mg/kg daily for 7 days. Dose-limiting toxicity was reversible neurotoxicity. The overall response rate was 42%. In previously untreated older patients, the response rate was 52%. Median number of courses to response was 1 (range, 1-3 courses). Median remission duration was 26 weeks, and median survival has not been reached. A significant decrease in global DNA methylation and induction of histone acetylation were achieved. VPA blood levels were higher in responders (P < .005). In conclusion, the combination studied is safe and has significant clinical activity. This clinical trial was registered at www.clinicaltrials.gov as no. NCT00326170.
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PMID:Safety and clinical activity of the combination of 5-azacytidine, valproic acid, and all-trans retinoic acid in acute myeloid leukemia and myelodysplastic syndrome. 1759 41

Valproic acid (VPA) has been used as an anticonvulsant for decades. Recently, it was demonstrated that VPA also acts as a histone deacetylase inhibitor and induces differentiation and apoptosis in a variety of malignant cells in vitro. The effect of VPA on tumor cells differs according to cell type, degree of differentiation, and underlying genetic alterations. Clinical trials with VPA have focused on acute myeloid leukemia and the myelodysplastic syndromes. When it was used as monotherapy or in combination with all-trans retinoic acid, which synergizes in vitro, VPA achieved hematologic improvement in a subset of patients. Similar to other inhibitors of histone deacetylases, complete or partial remissions rarely were observed. In this report, the authors reviewed the in vitro and in vivo data obtained with VPA, and they considered possible combination regimens aimed at improving therapeutic efficacy.
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PMID:Valproic acid for the treatment of myeloid malignancies. 1834 2

Epigenetic alterations, such as DNA methylation and histone modifications, are abnormal in cancer cells, and the use of the hypomethylating agents 5-azacitidine and decitabine are important additions to our arsenal of active cancer drugs, especially for the treatment of the myelodysplastic syndromes and acute myeloid leukemia. Most effective are repeated cycles of the drugs given at doses much lower than originally tested. Typical overall response rates (complete responses + partial responses + hematologic improvement) for both drugs are in the range of 40 - 50%. These agents are generally very well tolerated, with myelosuppression being the major side effect. Postulated to work through hypomethylation of DNA causing induction of gene expression, the precise mechanism of action of these agents is not yet clear. Future studies are likely to combine these agents with other drugs like the histone deacetylase inhibitors that act in related pathways.
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PMID:The use of hypomethylating agents in the treatment of hematologic malignancies. 1778 3

We analysed the in vitro effects of a new hydroxamate derivative, ITF2357, on AML cells. ITF2357 potently induced histone acetylation. ITF2357 0.1 microM blocked proliferation and induced apoptosis in AML1/ETO-positive Kasumi-1 cells, while AML1/ETO-negative HL60, THP1 and NB4 cell lines were sensitive only to 1 microM ITF2357. Apoptosis was induced by 0.1 microM ITF2357 in AML1/ETO-positive primary blasts and U937-A/E cells induced to express AML1/ETO, but not in U937-A/E cells non-expressing AML1/ETO. In Kasumi-1 cells 0.1 microM ITF2357 induced AML1/ETO degradation through a caspase-dependent mechanism. ITF2357 0.1 microM also determined DNMT1 efflux from, and p300 influx to, the nucleus. Moreover, 0.1 microM ITF2357 determined local H4 acetylation and release of DNMT1, HDAC1 and AML1/ETO, paralleled by recruitment of p300 to the IL-3 gene promoter. ITF2357 treatment, however, did not induce re-expression of IL-3 gene. Accordingly, the methylation level of IL-3 promoter, as well as of several other genes, was unmodified. In conclusion, ITF2357 emerged as an anti-leukaemic agent very potent on AML cells, and on AML1/ETO-positive cells in particular. More relevantly, clearly emerged from our results that ITF2357 could be an ideal agent to treat AML subtypes presenting AML1/ETO fusion protein which determine HDAC involvement in leukaemogenesis.
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PMID:Selective anti-leukaemic activity of low-dose histone deacetylase inhibitor ITF2357 on AML1/ETO-positive cells. 1789 Nov 69

Vorinostat (suberoylanilide hydroxamic acid, SAHA) is a histone deacetylase inhibitor active clinically in cutaneous T-cell lymphoma and preclinically in leukemia. A phase 1 study was conducted to evaluate the safety and activity of oral vorinostat 100 to 300 mg twice or thrice daily for 14 days followed by 1-week rest. Patients with relapsed or refractory leukemias or myelodysplastic syndromes (MDS) and untreated patients who were not candidates for chemotherapy were eligible. Of 41 patients, 31 had acute myeloid leukemia (AML), 4 chronic lymphocytic leukemia, 3 MDS, 2 acute lymphoblastic leukemia, and 1 chronic myelocytic leukemia. The maximum tolerated dose (MTD) was 200 mg twice daily or 250 mg thrice daily. Dose-limiting toxicities were fatigue, nausea, vomiting, and diarrhea. Common drug-related adverse experiences were diarrhea, nausea, fatigue, and anorexia and were mild/moderate in severity. Grade 3/4 drug-related adverse experiences included fatigue (27%), thrombocytopenia (12%), and diarrhea (10%). There were no drug-related deaths; 7 patients had hematologic improvement response, including 2 complete responses and 2 complete responses with incomplete blood count recovery (all with AML treated at/below MTD). Increased histone acetylation was observed at all doses. Antioxidant gene expression may confer vorinostat resistance. Further evaluation of vorinostat in AML/MDS is warranted.
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PMID:Phase 1 study of the histone deacetylase inhibitor vorinostat (suberoylanilide hydroxamic acid [SAHA]) in patients with advanced leukemias and myelodysplastic syndromes. 1796 10

R306465 is a novel hydroxamate-based histone deacetylase (HDAC) inhibitor with broad-spectrum antitumour activity against solid and haematological malignancies in preclinical models. R306465 was found to be a potent inhibitor of HDAC1 and -8 (class I) in vitro. It rapidly induced histone 3 (H3) acetylation and strongly upregulated expression of p21waf1,cip1, a downstream component of HDAC1 signalling, in A2780 ovarian carcinoma cells. R306465 showed class I HDAC isotype selectivity as evidenced by poor inhibition of HDAC6 (class IIb) confirmed by the absence of downregulation of Hsp90 chaperone c-raf protein expression and tubulin acetylation. This distinguished it from other HDAC inhibitors currently in clinical development that were either more potent towards HDAC6 (e.g. vorinostat) or had a broader HDAC inhibition spectrum (e.g. panobinostat). R306465 potently inhibited cell proliferation of all main solid tumour indications, including ovarian, lung, colon, breast and prostate cancer cell lines, with IC50 values ranging from 30 to 300 nM. Haematological cell lines, including acute lymphoblastic leukaemia, acute myeloid leukaemia, chronic lymphoblastic leukaemia, chronic myeloid leukaemia, lymphoma and myeloma, were potently inhibited at a similar concentration range. R306465 induced apoptosis and inhibited angiogenesis in cell-based assays and had potent oral in vivo antitumoral activity in xenograft models. Once-daily oral administration of R306465 at well-tolerated doses inhibited the growth of A2780 ovarian, H460 lung and HCT116 colon carcinomas in immunodeficient mice. The high activity of R306465 in cell-based assays and in vivo after oral administration makes R306465 a promising novel antitumoral agent with potential applicability in a broad spectrum of human malignancies.
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PMID:R306465 is a novel potent inhibitor of class I histone deacetylases with broad-spectrum antitumoral activity against solid and haematological malignancies. 1800 Apr 99

Currently available chemotherapy has probably reached the limits of its potential in treating acute myeloid leukemia (AML). In considering the next steps it is appropriate to exploit on the one hand knowledge of the molecular, immunophenotypic and biological characteristics of the disease and on the other the biology of the patient. The aim is to move towards a more targeted approach. Immunophenotyping has defined an adequate target (CD33) for antibody-directed treatment, although this is not leukemia specific. Monotherapy has produced important response rates in relapsed disease but it is unlikely to displace conventional chemotherapy. Several randomized trials of antibody directed chemotherapy in combination with chemotherapy nearing completion will establish the usefulness of this approach. In most patients a leukemia-specific immunophenotype can be characterized that can be used to monitor treatment. Minimal residual disease (MRD) detection in morphological remission can detect patients at high risk of relapse, as can a limited number of molecular markers. The clinical value of intervening at the time of MRD detection is not clear. Among the increasing molecular abnormalities described in AML, FLT-3 mutations appear the most attractive for therapeutic intervention. Several phase 2 studies have shown limited efficacy, and randomized trials in combination are underway. Other mechanisms that can be specifically targeted include farnesylation, methylation status, and histone deacelylation. Newer knowledge about the immunophenotypic and biological characteristics of the leukemic stem cell population has opened opportunities to develop treatments that exploit characteristics of the leukemic stem cells that differ from the normal stem cell. Some of these initiatives are now discussed.
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PMID:Targeting treatment in AML. 1802 61

The basic helix-loop-helix (bHLH) transcription factor family contains key regulators of cellular proliferation and differentiation as well as the suspected oncoproteins Tal1 and Lyl1. Tal1 and Lyl1 are aberrantly over-expressed in leukemia as a result of chromosomal translocations, or other genetic or epigenetic events. Protein-protein and protein-DNA interactions described so far are mediated by their highly homologous bHLH domains, while little is known about the function of other protein domains. Hetero-dimers of Tal1 and Lyl1 with E2A or HEB, decrease the rate of E2A or HEB homo-dimer formation and are poor activators of transcription. In vitro, these hetero-dimers also recognize different binding sites from homo-dimer complexes, which may also lead to inappropriate activation or repression of promoters in vivo. Both mechanisms are thought to contribute to the oncogenic potential of Tal1 and Lyl1. Despite their bHLH structural similarity, accumulating evidence suggests that Tal1 and Lyl1 target different genes. This raises the possibility that domains flanking the bHLH region, which are distinct in the two proteins, may participate in target recognition. Here we report that CREB1, a widely-expressed transcription factor and a suspected oncogene in acute myelogenous leukemia (AML) was identified as a binding partner for Lyl1 but not for Tal1. The interaction between Lyl1 and CREB1 involves the N terminal domain of Lyl1 and the Q2 and KID domains of CREB1. The histone acetyl-transferases p300 and CBP are recruited to these complexes in the absence of CREB1 Ser 133 phosphorylation. In the Id1 promoter, Lyl1 complexes direct transcriptional activation. We also found that in addition to Id1, over-expressed Lyl1 can activate other CREB1 target promoters such as Id3, cyclin D3, Brca1, Btg2 and Egr1. Moreover, approximately 50% of all gene promoters identified by ChIP-chip experiments were jointly occupied by CREB1 and Lyl1, further strengthening the association of Lyl1 with Cre binding sites. Given the newly recognized importance of CREB1 in AML, the ability of Lyl1 to modulate promoter responses to CREB1 suggests that it plays a role in the malignant phenotype by occupying different promoters than Tal1.
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PMID:Lyl1 interacts with CREB1 and alters expression of CREB1 target genes. 1816 48

Flow cytometric techniques have emerged as a powerful tool in hematology allowing fast, sensitive and reproducible multi-parametric analyses at the single cell level of heterogeneous samples. Small subsets of cells can be studied with high degree of accuracy, and a broad and constantly increasing specter of antibodies is available. Flow cytometry has therefore become the method of choice for evaluation of therapeutic effects at single cell level. These methodological approaches can easily be used to study hematological malignancies, and the future use of this strategy in other malignancies will depend on the development of laboratory techniques to prepare suspensions of viable cells also from tumor biopsies. The selection of biological parameters for evaluation of treatment effects should probably be based on (i) molecular markers involved in cancer-associated genetic abnormalities; (ii) other molecular markers showing altered expression in the malignant cells and thought to be involved in leukemogenesis or having a prognostic impact; (ii) functional assays known to reflect biological characteristics that are important in carcinogenesis (e.g. cell cycle distribution, functional evaluation of apoptosis regulation). These molecules will in addition often represent the therapeutic targets when new anticancer drugs are developed. In this review we use treatment of acute myeloid leukemia with histone deacetylase inhibitors as an example. Based on the criteria mentioned above we suggest that the monitoring of therapeutic effects on the cancer cells in these patients should include differentiation status, histone acetylation, cell cycle distribution, pro- and anti-apoptotic signaling balance and intracellular levels of various transcription factors.
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PMID:Epigenetic targeting in acute myeloid leukemia: use of flow cytometry in monitoring therapeutic effects. 1828 49


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