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

Cytochrome P450 2E1 (CYP2E1) has active roles in bioconversion and biotransformation in humans. Although predominantly present in hepatocytes, CYP2E1 has also been found in hematopoietic stem cells and subtypes of acute myeloid leukemia with unknown clinical significance except for the metabolism of anti-fungal drugs. In the present study, we demonstrated a novel role of CYP2E1 inducing megakaryocyte development in human hematopoietic stem cells and leukemia bipotent K562 cells. CYP2E1 was induced by phorbol-12-myristate-13-acetate in dose-dependent manner in K562 cells as well as in hematopoietic stem cells by thrombopoietin, and ingenol 3,20-dibenzoate (IDB), respectively. Overexpression of CYP2E1 was positively correlated with megakaryocytes and in megakaryocyte maturation. In addition, plasmid-driven expression of CYP2E1 in K562 cells led to morphological transformation of leukemic blasts to pro- and mature megakaryocytes. In contrast, knockout of CYP2E1 by specific interfering RNA diverted these cells to erythroid differentiation. Finally, treatment of K562 cells by a free radical scavenger, N-acetyl L-lysine significantly inhibited CYP2E1 and megakaryocyte differentiation. In summary, our data demonstrated that activation of CYP2E1 and reactive oxygen species signaling promotes megakaryocyte development.
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PMID:A novel role of CYP2E1 in human megakaryocyte development. 2539 2

Current valid treatments for acute myeloid leukemia (AML) include chemotherapy and hematopoietic stem cell transplantation, which are defective and limited respectively. The insulin-like growth factor 1 receptor (IGF-1R) is up-regulated in many solid tumors; therefore, it may be a target for tumor therapy. Interestingly, IGF-1R is modified by SUMOylation, a type of reversible post-translational modification. In this study, we found that IGF-1R was increased in both cell lines and clinical samples of AML and was modified by SUMO-1. Furthermore, IGF-1, ligand of IGF-1R, induced the up-regulation of IGF-1R and increased the proliferation of leukemia cell line. After mutation of Lys(1025) and Lys(1100) in IGF-1R, the evolutionarily conserved lysine residues were identified as the SUMOylation sites of IGF-1R, because the SUMOylation of IGF-1R in these mutants was significantly inhibited. Furthermore, the cell proliferation mediated by IGF-1 was also reduced. After inhibition of UBC9, the activating enzyme of SUMOylation, co-expression of IGF-1R and SUMO-1 was down-regulated, and cell proliferation was also inhibited. However, cell apoptosis was not significantly affected. These results suggest that IGF-1R and its SUMOylation may be a new therapeutic target for strategy of AML.
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PMID:SUMOylation of insulin-like growth factor 1 receptor, promotes proliferation in acute myeloid leukemia. 2544 1

In cancer, epigenetic proteins are intensely studied targets for therapeutic drug discovery, showing great promise. These proteins include the chromatin-modifying enzymes that "write" and "erase" histone posttranslational modifications (PTM), and those that "read" these marks through binding modules. In an effort to find a compound that could disrupt the protein-protein interactions between a PTM and reader, JQ1 has proven to be a first-in-class, drug-like inhibitor of the "bromodomain and extraterminal domain" epigenetic readers (BETs), which recognize histone lysine acetylation marks. JQ1 has facilitated the mechanistic study and therapeutic application in cancer of this kind of epigenetic inhibition. By using this chemical probe, we have discovered that the bromodomain inhibitors (BETi) have compelling activity in preclinical models of multiple myeloma and acute myeloid leukemia. In particular, BETi down-regulates the MYC, IL-7R, and E2F transcriptional programs. We are continuously integrating the transcriptional consequences of BETi with changes in the epigenomic landscapes of cancer cells to elucidate the mechanisms underlying response to BETi using chemical and genetic perturbations.
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PMID:Bromodomain and extraterminal domain inhibitors (BETi) for cancer therapy: chemical modulation of chromatin structure. 2545 84

Cellular senescence is an important mechanism that restricts tumour growth. The Ink4a-Arf locus (also known as Cdkn2a), which encodes p16(INK4A) and p19(ARF), has a central role in inducing and maintaining senescence. Given the importance of cellular senescence in restraining tumour growth, great emphasis is being placed on the identification of novel factors that can modulate senescence. The MYST-family histone acetyltransferase MOZ (MYST3, KAT6A), first identified in recurrent translocations in acute myeloid leukaemia, has been implicated in both the promotion and inhibition of senescence. In this study, we investigate the role of MOZ in cellular senescence and show that MOZ is a potent inhibitor of senescence via the INK4A-ARF pathway. Primary mouse embryonic fibroblasts (MEFs) isolated from Moz-deficient embryos exhibit premature senescence, which was rescued on the Ink4a-Arf(-/-) background. Importantly, senescence resulting from the absence of MOZ was not accompanied by DNA damage, suggesting that MOZ acts independently of the DNA damage response. Consistent with the importance of senescence in cancer, expression profiling revealed that genes overexpressed in aggressive and highly proliferative cancers are expressed at low levels in Moz-deficient MEFs. We show that MOZ is required to maintain normal levels of histone 3 lysine 9 (H3K9) and H3K27 acetylation at the transcriptional start sites of at least four genes, Cdc6, Ezh2, E2f2 and Melk, and normal mRNA levels of these genes. CDC6, EZH2 and E2F2 are known inhibitors of the INK4A-ARF pathway. Using chromatin immunoprecipitation, we show that MOZ occupies the Cdc6, Ezh2 and Melk loci, thereby providing a direct link between MOZ, H3K9 and H3K27 acetylation, and normal transcriptional levels at these loci. This work establishes that MOZ is an upstream inhibitor of the INK4A-ARF pathway, and suggests that inhibiting MOZ may be one way to induce senescence in proliferative tumour cells.
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PMID:MOZ (MYST3, KAT6A) inhibits senescence via the INK4A-ARF pathway. 2577 42

Securinega alkaloids represent a family of plant secondary metabolites known for 50 years. Securinine (1), the most abundant and studied alkaloid of this series was isolated by Russian researchers in 1956. In the following years, French and Japanese scientists reported other Securinega compounds and extensive work was done to elucidate their intriguing structures. The homogeneity of this family relies mainly on its tetracyclic chemical backbone, which features a butenolide moiety (cycle D) and an azabicyclo[3.2.1]octane ring system (rings B and C). Interestingly, after a period of latency of 20 years, the Securinega topic reemerged as a prolific source of new natural structures and to date more than 50 compounds have been identified and characterized. The oligomeric subgroup gathering dimeric, trimeric, and tetrameric units is of particular interest. The unprecedented structure of the Securinega alkaloids was the subject of extensive synthetic efforts culminating in several efficient and elegant total syntheses. The botanical distribution of these alkaloids seems limited to the Securinega, Flueggea, Margaritaria, and Breynia genera (Phyllanthaceae). However, only a limited number of plant species have been considered for their alkaloid contents, and additional phytochemical as well as genetic studies are needed. Concerning the biosynthesis, experiments carried out with radiolabelled aminoacids allowed to identify lysine and tyrosine as the precursors of the piperidine ring A and the CD rings of securinine (1), respectively. Besides, plausible biosynthetic pathways were proposed for virosaine A (38) and B (39), flueggine A (46), and also the different oligomers flueggenine A-D (48-51), fluevirosinine A (56), and flueggedine (20). The case of nirurine (45) and secu'amamine (37) remains elusive and additional studies seem necessary to understand their mode of production. The scope of biological of activities of the Securinega alkaloids was mainly centered on the CNS activity of securinine (1), although the exact mechanism of action remained in part unknown. Nevertheless, for its stimulant and antispasmodic effects securinine nitrate was marketed as a drug in the USSR until the early 1990s. Moreover, securinine (1) and several other Securinega alkaloids recently demonstrated promising anticancer properties. In particular securinine (1) demonstrated markedly benefits in the treatment of acute myeloid leukemia.
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PMID:The Securinega alkaloids. 2584 59

Growing evidence links abnormal epigenetic control to the development of hematological malignancies. Accordingly, inhibition of epigenetic regulators is emerging as a promising therapeutic strategy. The acetylation status of lysine residues in histone tails is one of a number of epigenetic post-translational modifications that alter DNA-templated processes, such as transcription, to facilitate malignant transformation. Although histone deacetylases are already being clinically targeted, the role of histone lysine acetyltransferases (KAT) in malignancy is less well characterized. We chose to study this question in the context of acute myeloid leukemia (AML), where, using in vitro and in vivo genetic ablation and knockdown experiments in murine models, we demonstrate a role for the epigenetic regulators CBP and p300 in the induction and maintenance of AML. Furthermore, using selective small molecule inhibitors of their lysine acetyltransferase activity, we validate CBP/p300 as therapeutic targets in vitro across a wide range of human AML subtypes. We proceed to show that growth retardation occurs through the induction of transcriptional changes that induce apoptosis and cell-cycle arrest in leukemia cells and finally demonstrate the efficacy of the KAT inhibitors in decreasing clonogenic growth of primary AML patient samples. Taken together, these data suggest that CBP/p300 are promising therapeutic targets across multiple subtypes in AML.
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PMID:The epigenetic regulators CBP and p300 facilitate leukemogenesis and represent therapeutic targets in acute myeloid leukemia. 2589 91

The recent advances in our understanding of leukemogenesis have clearly demonstrated that human acute myeloid leukemia is a heterogeneous malignancy, and several disease mechanisms should probably be regarded as possible therapeutic targets only for specific subsets of patients and not for acute myeloid leukemia in general. One promising strategy for epigenetic targeting is inhibition of the binding between bromodomain-containing transcription regulators and acetylated lysine residues on histones. This possible approach has been investigated especially for patients with 11q23 and chromosome 8 abnormalities. An alternative target is the histone methyltransferase COT1L. Major challenges for both approaches will be to clarify how these strategies should be combined with each other or with conventional chemotherapy, and whether their use should be limited to certain subsets of patients.
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PMID:Emerging therapeutic targets in human acute myeloid leukemia (part 2) - bromodomain inhibition should be considered as a possible strategy for various patient subsets. 2590 42

Acetylation is a well-characterized histone modification, which plays important roles in controlling epigenetic gene expression, and its malfunction is tightly associated with cancer. By taking advantage of the specific binding of BRD4 to acetylated lysine residues, we developed a FRET-based probe for visualizing histone H3 acetylation in living cells. BRD4, a protein known to be involved in acute myeloid leukemia and nuclear protein in testis midline carcinoma, recognizes the acetylation of histone H3 via its bromodomains. The probe exhibited a significant change in FRET signaling that was dependent on histone H3 acetylation. Mutagenesis studies revealed that an increase in the emission ratio reflected the acetylation of either K9 or K14 of histone H3 within the probe. Since BRD4 has increasingly drawn attention as a new anticancer drug target, we demonstrated that the developed fluorescent probe will also serve as a powerful tool to evaluate BRD4 inhibitors in living cells.
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PMID:A Genetically Encoded FRET Probe to Detect Intranucleosomal Histone H3K9 or H3K14 Acetylation Using BRD4, a BET Family Member. 2594 8

Epigenetic modifying enzymes have a crucial role in the pathogenesis of acute myeloid leukemia (AML). Methylation of lysine 9 on histone H3 by the methyltransferase G9a and SUV39H1 is associated with inhibition of tumor suppressor genes. We studied the effect of G9a and SUV39H1 inhibitors on viability and differentiation of AML cells and tested the cytotoxicity induced by combination of G9a and SUV39H1 inhibitors and various epigenetic drugs. The SUV39H1 inhibitor (chaetocin) and the G9a inhibitor (UNC0638) caused cell death in AML cells at high concentrations. However, only chaetocin-induced CD11b expression and differentiation of AML cells at non-cytotoxic concentration. HL-60 and KG-1a cells were more sensitive to chaetocin than U937 cells. Long-term incubation of chaetocin led to downregulation of SUV39H1 and reduction of H3K9 tri-methylation in HL-60 and KG-1a cells. Combination of chaetocin with suberoylanilide hydroxamic acid (SAHA, a histone deacetylase inhibitor) or JQ (a BET (bromodomain extra terminal) bromodomain inhibitor) showed synergistic cytotoxicity. Conversely, no synergism was found by combining chaetocin and UNC0638. More importantly, chaetocin-induced differentiation and combined cytotoxicity were also found in the primary cells of AML patients. Collectively, the SUV39H1 inhibitor chaetocin alone or in combination with other epigenetic drugs may be effective for the treatment of AML.
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PMID:The SUV39H1 inhibitor chaetocin induces differentiation and shows synergistic cytotoxicity with other epigenetic drugs in acute myeloid leukemia cells. 2597 33

IDH1/2 mutations which result in alternation in DNA methylation pattern are one of the most common methylation associated mutations in Acute myeloid leukaemia. IDH1/2 mutations frequently associated with higher platelet level, normal cytogentics and NPM1 mutations. Here we analyzed IDH1/2 mutations in 200 newly diagnosed unselected Indian adult AML patients and investigated their correlation with clinical, cytogenetic parameters along with cooperating NPM1 mutation. We detected 5.5% and 4% mutations in IDH1/2 genes, respectively. Except IDH2 c.515_516GG>AA mutation, all the other identified mutations were reported mutations. Similar to reported c.515G>A mutation, the novel c.515_516GG>AA mutation replaces 172nd arginine to lysine in the active site of the enzyme. Even though there was a preponderance of IDH1/2 mutations in NK-AML, cytogenetically abnormal patients also harboured IDH1/2 mutations. IDH1 mutations showed significant higher platelet count and NPM1 mutations. IDH2 mutated patients displayed infrequent NPM1 mutations and lower WBC count. All the NPM1 mutations in the IDH1/2 mutated cases showed type A mutation. The present data suggest that IDH1/2 mutations are associated with normal cytogenetics and type A NPM1 mutations in adult Indian AML patients.
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PMID:Mutation Analysis of IDH1/2 Genes in Unselected De novo Acute Myeloid Leukaemia Patients in India - Identification of A Novel IDH2 Mutation. 2598 93


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