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)

Twenty two patients with acute relapsed leukemia (AML 20, ALL 2) were treated with 5-aza-2'-deoxycytidine (DAC) and either m-amsacrine or idarubicin. DAC was administered as a 6-h infusion, every 12 h for 6 days in combination with either m-amsacrine (120 mg/m2) as a 1-h infusion on days 6 and 7 (n = 19) or idarubicin (12 mg/m2) as a 15-min infusion on days 5, 6 and 7 (n = 3). Thirteen patients (59%) achieved a complete remission. The treatment was complicated by nausea, vomiting, diarrhoea with signs of peritonitis (n = 9), weight loss (n = 7), cerebellar or cerebral toxicity (n = 2), gastrointestinal bleeding (n = 3), liver toxicity (n = 2) and prolonged myelosuppression. Median duration of remission was 4 months (range 1-30). The preliminary data show that DAC is an anti-leukemic agent, comparable to high dose Ara-C with comparable severe toxicity.
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PMID:Preliminary results with 5-aza-2'-deoxycytidine (DAC)-containing chemotherapy in patients with relapsed or refractory acute leukemia. The EORTC Leukemia Cooperative Group. 768 57

Deoxycytidine kinase activity (dCk) was monitored in cell lines from a rat acute myeloid leukemia model of acquired resistance to cytosine arabinoside (AraC) and decitabine (DAC). In both AraC-resistant cell lines (RCL/A and its subclone RA/7), as well as in a DAC-resistant cell line (RCL/D) which we generated from the drug-sensitive RCL/0 cell line, a total deficiency of dCk activity and a cross-resistance for AraC and DAC was demonstrated. Furthermore, the metabolization of deoxycytidine (dC) was severely impaired in all these cell lines. Km values for dC (9.4 microM in RCL/0 cells) had increased 70- to 100-fold in RCL/D (Km = 673.2 microM), in RCL/A (Km = 947.2 microM) and in RA/7 (Km = 817.5 microM). Vmax values were unaltered in RCL/D and RA/7, and twofold increased in RCL/A. Addition of hydroxyurea (HU) to cell cultures stimulated dCk salvage pathway activity in RCL/0 cells for dC, AraC, and DAC by increasing Vmax values approximately 160% leaving Km constants unchanged. In all resistant cell lines, HU pre-incubation did not influence the level of dCk activity, leaving Km and Vmax values unaltered. These data indicate that deficiency of dCk activity is crucial in the mechanism of drug resistance in this model.
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PMID:Role of deoxycytidine kinase in an in vitro model for AraC- and DAC-resistance: substrate-enzyme interactions with deoxycytidine, 1-beta-D-arabinofuranosylcytosine and 5-aza-2'-deoxycytidine. 768 1

The overall cure rate of adults with newly-diagnosed acute myelogenous leukemia (AML) treated with continuous infusion high-dose cytarabine (CIHDAC) is comparable to that with standard-dose ara-C plus anthracycline or amsacrine (AMSA). We tested whether the addition of AMSA to CIH-DAC improves the outcome of adults with untreated AML. 75 patients with untreated AML were treated with AMSA (75 mg/m2/day x 4) plus CIHDAC (1.5 g/m2/day x 4) for induction and, if in complete remission (CR), early and late intensification. Results were compared to those in 129 patients treated on a previous study with CIHDAC alone. The principal comparison in both groups was between those 117 patients (AMSA/CIHDAC n = 52, CIHDAC n = 65) who met the initial eligibility criteria for the AMSA/CIHDAC study (risk of early mortality < or = 1) and who were treated at a time when relatively few eligible patients were excluded (19% in the AMSA/CIHDAC group, 34% in the CIHDAC group). There was no difference between regimens in CR rate, remission duration, or survival in this cohort. When attention was turned to all 204 patients, outcome was superior with AMSA/CIHDAC very largely as a result of outcome in patients with APL. Aside from these patients, addition of amsacrine to CIHDAC did not appear to be productive.
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PMID:Amsacrine and continuous-infusion high-dose cytosine arabinoside as induction therapy for patients with newly-diagnosed acute myelogenous leukemia. 872 30

Two deoxycytidine analogues, 1-beta-D-arabinofuranosylcytosine (cytosine arabinoside, citarabine, araC) and 5-aza-2'-deoxycytidine (decitabine, DAC, 5-aza-dC), are the drugs of choice in the treatment of acute myeloid leukaemia. The araC-induced cytotoxicity is a direct result of its interference with nucleic acids synthesis, whereas 5-aza-dC is a potent suppressor of DNA methylation. We employed the standard version of the wing somatic mutation and recombination test (SMART) in Drosophila melanogaster to evaluate the genotoxic potential of these two antimetabolites as a function of exposure concentration. In addition, we determined the relative contributions of mutational and recombinational events to total genotoxicity. The compounds were administered by chronic feeding of 3-day-old larvae. Our results indicate that recombinagenicity is the major genotoxic effect of araC and 5-aza-dC (approximately, 77 and 81%, respectively, recombination). The standardised clone induction frequencies (per mM concentration per cell per cell division) show that 5-aza-dC is 85 times more powerful then araC (inducing approximately 58 mutant clones per 10(5) cells per mM). The high recombinagenic activity of these two drugs suggests that--despite their therapeutic effects against cancer--a question is raised whether these drugs should be considered for adverse effects in cancer chemotherapy.
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PMID:Somatic recombination: a major genotoxic effect of two pyrimidine antimetabolitic chemotherapeutic drugs in Drosophila melanogaster. 1181 48

Decitabine [NSC 127716, DAC, dezocitidine, Aza dC, 2'-deoxy-5-azacytidine] is a deoxycytidine and cytarabine derivative with potent antileukaemic activity, which was originated by Pharmachemie. This antimetabolite is able to induce in vitro gene activation and cellular differentiation by a mechanism involving DNA hypomethylation. SuperGen acquired worldwide rights to decitabine from Pharmachemie in the third quarter of 1999 for 4 million US dollars worth of SuperGen shares and income from manufacture upon the launch of decitabine. SuperGen announced in May 2000 that it had entered a Cooperative Research and Development Agreement (CRADA) with the US National Cancer Institute (NCI). SuperGen will supply decitabine to the NCI, which will initiate and sponsor clinical trials in patients with solid tumours and haematological malignancies. The NCI will also conduct studies on decitabine's mechanism of action. In 2002, the US FDA has granted decitabine orphan drug status for the treatment of myelodysplastic syndromes and sickle cell anaemia. In February 2003, the European Commission granted orphan drug status to decitabine for myelodysplastic syndrome. Decitabine has also received orphan drug status in the US as a host-protective agent in the treatment of AML. Decitabine has been studied in solid tumours as well as in different types of leukaemia. In several phase II studies it has been shown to have very limited efficacy against solid tumours. However, decitabine has shown better activity in the treatment of haematological malignancies such as acute myeloid leukaemia (AML), chronic myeloid leukaemia (CML) and myelodysplastic syndrome (preleukaemia). In March 2001, SuperGen announced that it had begun patient enrolment into its pivotal open-label phase III trial of decitabine in advanced myelodysplastic syndrome patients. The study, which will compare decitabine with standard care therapy, will be conducted at 15 medical centres in the US and will enrol a total of 160 patients. In March 2003, SuperGen announced that patient enrolment was complete. The study, which will compare decitabine with standard care therapy, will be conducted at 22 medical centres in the US and will enrol a total of 160 patients. A European pivotal trial is also underway for the same indication, and is aiming to enrol 220 patients. A phase I/II trial of 8 patients, designed to establish safety and efficacy in the treatment of sickle cell anaemia, has been completed at the University of Illinois, USA. Plans for additional studies of decitabine as a treatment for sickle cell anaemia are underway. Decitabine is also undergoing phase II clinical trials in Canada, for the treatment of non-small cell lung cancer, and in the US for chronic myeloid leukaemia and prostate cancer. Glasgow University in Scotland has conducted preclinical trials in chemotherapy-resistant ovarian and colon cancers. The results suggest that decitabine administration may reverse chemotherapy resistance in these cancers. SuperGen was issued a US patent (No. 6 191 119) in 2001 covering the use of decitabine in combination with rubitecan and antibiotic agents, including doxorubicin.
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PMID:Decitabine: 2'-deoxy-5-azacytidine, Aza dC, DAC, dezocitidine, NSC 127716. 1275 5

Decitabine (DAC) is a small molecule nucleotide analog that is incorporated into DNA and traps human DNA methyltransferases. Although initially developed as a cytotoxic agent, low-dose DAC is enjoying a revival as a specific inhibitor of hypermethylation in cancer. DAC has activity in several hematological diseases, especially myelodysplastic syndrome, chronic myelogenous leukemia and acute myeloid leukemia. Clinical and preclinical advances are presented in this review.
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PMID:Decitabine: development of a DNA methyltransferase inhibitor for hematological malignancies. 1476 30

The demethylating effect of 5-aza-2' deoxycytidine (decitabine, DAC) has been well characterized. The molecular events downstream of methylation inhibition are less well known. Here, DAC was shown to induce apoptosis in acute myeloid leukemia (AML) cells (p53 mutant and wild type) but not in epithelial or normal peripheral blood mononuclear cells. Apoptosis was characterized by activation of the mitochondrial but not the receptor death pathway, as demonstrated by the release of cytochrome c and loss of mitochondrial membrane potential. Western blotting and enzyme assays showed that caspase-3, but not caspase-6 or caspase-8, were activated. Decitabine induced expression of the cell cycle inhibitor p21, arresting AML cell lines in G1 of the cell cycle. Expression of p21 was induced irrespective of the methylation status of its promoter, mediated instead via reexpression of the tumor suppressor p73, an upstream regulator of p21. The promoter of p73 was hypermethylated in AML cell lines in vitro and in primary AML cells ex vivo but not in DAC-resistant epithelial cells. In conclusion, DAC acts on leukemic myeloid cells via caspase activation, which may be dependent on demethylation of the hypermethylated p73 promoter and consequent reexpression of p73.
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PMID:Decitabine activates specific caspases downstream of p73 in myeloid leukemia. 1619 3

Although the first studies using DNA demethylating agents at low doses in hematologic neoplasia and hemoglobinopathies were initiated more than 20 years ago, development of this type of nonintensive treatment has only been spurred in the last 6 to 8 years by the discovery of many genes that are specifically hypermethylated in cancer. These provide a powerful rationale for using azanucleosides (and other small molecules being developed for DNA demethylation) as a novel means of pharmacologic targeting of cancer cells that is distinct from low-dose chemotherapy. Encouraging response rates of about 50% in myelodysplasia with 5-azacytidine and 5-aza-2'-deoxycytidine (decitabine or DAC) have resulted in a number of phase III studies being initiated in this disorder. The development of such drugs for the treatment of acute myeloid leukemia (AML) is ongoing. While the specificity of DNA demethylation has been delineated by studying distinct genes or sets of genes, and proof-of-principle studies of in vivo methylation report demethylation and reactivation of genes like p15/INK4b and gamma-globin, responses to demethylating agents may be more complex. Specifically, so-called cancer testis antigens (CTAs) are intriguing targets for demethylation, since they are silenced in many hematopoietic disorders and may be reactivated by epigenetic therapy. Thus, demethylating agents and histone deacetylase inhibitors may also induce a T-cell-mediated antileukemic or antitumor effect.
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PMID:Epigenetic treatment of hematopoietic malignancies: in vivo targets of demethylating agents. 1621 92

Low-dose demethylating agents such as 5-aza-2'-deoxycytidine (decitabine, DAC) and 5-azacytidine (azacitidine, Vidaza) have been explored for the treatment of myelodysplasia, acute myeloid leukemia, and hemoglobinopathies since the early 1980s, aiming to revert a methylator phenotype. Originally, the treatment rationale in hemoglobinopathies was to achieve demethylation of the hypermethylated and hence silent gamma-globin gene locus, thus reactivating synthesis of hemoglobin F (HbF). In myelodysplastic syndrome (MDS), cytogenetic analyses are mandatory for risk stratification and for monitoring response to drug treatment. The current knowledge regarding cytogenetic subgroups as predictors of response to low-dose decitabine in MDS as well as cytogenetic responses caused by demethylating agents is summarized in this review. Decitabine treatment is associated with a response rate that is higher in patients with high-risk cytogenetics (i.e., complex karyotype and/or abnormalities of chromosome 7) than in patients with intermediate-risk cytogenetics (two abnormalities or single abnormalities excluding 5q-, 20q-, and -Y). Following decitabine treatment of patients with abnormal karyotype, approximately one-third achieve a major cytogenetic response that can be confirmed by FISH analyses, while in two-thirds of patients, the abnormal karyotype persists but hematologic improvement may be observed during continued treatment. The most frequently studied gene in myelodysplasia is the cell cycle regulator p15(INK4b). Hypermethylation of p15(INK4b) in MDS is reversed during treatment with decitabine, resulting in reactivation of this gene. In hemoglobinopathies, treatment with demethylating agents leads to reactivation of fetal HbF (the gamma-globin gene locus also possibly being another target for reactivation in MDS), and thus, HbF may potentially act as surrogate marker for activity of decitabine. Other, thus far unidentified hypermethylated genes may also be targets for demethylating agents.
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PMID:In vivo effects of decitabine in myelodysplasia and acute myeloid leukemia: review of cytogenetic and molecular studies. 1629 49

In vitro and in vivo, myeloid leukemic and preleukemic cells exhibit variable sensitivity to the antiproliferative and proapoptotic effects induced already at low concentrations of DNA methyltransferase (DNMT) inhibitors. The molecular mechanisms underlying this variable sensitivity of leukemic blasts to azanucleosides such as 5-azacytidine and 5-aza-2'-deoxycytidine (DAC) may involve modifier effects of specific fusion proteins such as AML1/ETO. The cyclin-dependent kinase inhibitor p15/INK4b is one potential target of DNA demethylating activity in AML and MDS where it is frequently silenced by hypermethylation. To study sensitivity to DAC in myeloid leukemia cells, we chose the myeloid cell lines Kasumi-1 (expressing AML1/ETO), KG-1 and KG-1a (both AML1/ETO-negative) all of which a highly methylated p15/INK4b gene. Treatment with DAC resulted in dose-dependent regional demethylation of p15/INK4b in Kasumi-1 and KG-1, but only to a modest degree in KG-1a cells. Demethylation was associated with induction of p15/INK4b protein expression. Growth-inhibitory and proapoptotic activity of DAC was significantly higher in Kasumi-1 than in KG-1a cells, and sensitization of cells to a cooperating effect of All-trans retinoic acid and of the histone deacetylase (HDAC) inhibitor Trichostatin A was observed. DAC-induced growth inhibition and apoptosis were enhanced when AML1/ETO was conditionally expressed in AML1/ETO-negative U-937 cells. In conclusion, hypomethylation and reactivation of p15/INK4b in myeloid cell lines are among the molecular events associated with DAC-induced growth arrest and apoptosis. Further studies of AML1/ETO as a modifier of the epigenotype and sensitivity of myeloid cells to inhibitors of DNMTs and HDACs appear warranted.
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PMID:Reversal of p15/INK4b hypermethylation in AML1/ETO-positive and -negative myeloid leukemia cell lines. 1705 12


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