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Deacetylase Inhibitors (deacetylase + inhibitor)
Kinds of Deacetylase Inhibitors Selected AbstractsNovel Histone Deacetylase Inhibitors: Cyclic Tetrapeptide with Trifluoromethyl and Pentafluoroethyl Ketones.CHEMINFORM, Issue 9 2005Binoy Jose Abstract For Abstract see ChemInform Abstract in Full Text. [source] Cell microarray platform for anticancer drug development,DRUG DEVELOPMENT RESEARCH, Issue 5 2007Min-Jung Lee Abstract Pharmacodynamic assessment of whether a drug has interacted with and modified its target is an essential component of molecularly targeted clinical trials. Although many trials are written with the intent to assess tumor biopsies, if available, thus far the great majority of early drug trials have used peripheral blood mononuclear cells (PBMC) as a tumor surrogate. Typically, PBMC are studied by low-throughput techniques such as Western blot. We present the use of a cell-based tissue microarray for assessment of anticancer drug activity in vivo. We demonstrate the utility of this technique for analysis of protein hyperacetylation in response to treatment with the histone deacetylase inhibitor, SNDX-275 in PBMC treated in vitro and in PBMC and bone marrow aspirates from patients in Phase I clinical trials with SNDX-275. We demonstrate that the cell microarray can be used to measure drug response in a high-throughput manner, allowing analysis of an entire trial on one or two glass slides. The cell microarray technique brings the advantages of the tissue microarray platform to the pharmacodynamic assessment of single cells, such as those isolated from bone marrow aspirates, fine needle aspirates, or malignant effusions, and to analysis of PBMC, the most commonly studied surrogate in oncology trials. Drug Dev Res 68:226,234, 2007. Published 2007 Wiley-Liss, Inc. [source] ORIGINAL ARTICLE: Solubilization of vorinostat by cyclodextrinsJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 5 2010Y. Y. Cai BSc Summary Background:, Vorinostat (suberoylanilide hydroxamic acid) is the first histone deacetylase inhibitor approved by US FDA for use in oncology. However, as a hydrophobic acid, its limited aqueous solubility poses a problem for parenteral delivery. Such limited solubility may also affect its oral bioavailability. Objective:, The aim of this study was to evaluate whether cyclodextrins (CDs), common excipients used in pharmaceutical industry, could increase the aqueous solubility of vorinostat. Methods:, The actual aqueous solubility of vorinostat was investigated by phase-solubility method. Molecular simulation was employed to predict the interaction energy and preferred orientation of vorinostat in CD cavities. Results:, Phase-solubility studies indicated that the solubility of vorinostat (7·24 × 10,1 mm) was substantially increased when complexed with various CDs, in the following order: randomly methylated-,-cyclodextrin (RM-,-CD) > hydroxypropyl-,-cyclodextrin (HP-,-CD) > ,-cyclodextrin > hydroxypropyl-,-cyclodextrin > Hydroxypropyl-,-cyclodextrin > ,-cyclodextrin. RM-,-CD 300 mm increased vorinostat solubility to 70·8 mm, almost two orders of magnitude higher than the baseline solubility. Such findings were in good agreement with the results obtained from molecular simulation. Conclusion:, CDs, particularly RM-,-CD and HP-,-CD, increased vorinostat's solubility. Future studies could be focused on the application of HP-,-CD in parenteral delivery of vorinostat or using RM-,-CD as an oral absorption enhancer. Molecular simulation appeared to be a useful tool for the selection of appropriate CD as excipient for drug delivery. [source] Synthesis of [phenyl-U- 14C]aryl and [8- 14C]carboxy labeled tracers of vorinostatJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 5 2006Eric D. Soli Abstract In support of a program to develop a treatment for advanced, refractory cutaneous T-cell lymphoma, two differentially [14C]-labeled forms of vorinostat, a histone deacetylase inhibitor, were synthesized for use in metabolism studies. Copyright © 2006 John Wiley & Sons, Ltd. [source] In vitro specificities of Arabidopsis co-activator histone acetyltransferases: implications for histone hyperacetylation in gene activationTHE PLANT JOURNAL, Issue 4 2007Keith W. Earley Summary In genetic hybrids displaying nucleolar dominance, acetylation of lysines 5, 8, 12 and 16 of histone H4 (H4K5, H4K8, H4K12, H4K16) and acetylation of histone H3 on lysines 9 and 14 (H3K9, H3K14) occurs at the promoters of active ribosomal RNA (rRNA) genes, whereas silenced rRNA genes are deacetylated. Likewise, histone hyperacetylation correlates with the active state of transgenes and of endogenous plant genes involved in physiological processes, including cold tolerance, light-responsiveness and flowering. To investigate histone hyperacetylation dynamics we used sodium butyrate, a histone deacetylase inhibitor known to switch silent rRNA genes on, in order to enrich the pool of acetylated histones. Mass spectrometric analyses revealed unique mono- (K16Ac), di- (K12Ac, K16Ac), tri- (K8Ac, K12Ac, K16Ac), and tetra-acetylated (K5Ac, K8Ac, K12Ac, K16Ac) histone H4 isoforms, suggesting that H4 hyperacetylation occurs in a processive fashion, beginning with lysine 16 and ending with lysine 5. Using a combination of molecular and mass spectrometric assays we then determined the specificities of seven of the nine functional co-activator type histone acetyltransferases (HATs) in Arabidopsis thaliana: specifically HATs of the CBP (HAC1, HAC5, HAC12), GNAT (HAG1, HAG2), and MYST families (HAM1, HAM2). Specific HATs acetylate histone H4K5 (HAM1, HAM2), H4K12 (HAG2), and H3K14 (HAG1), suggesting that acetylation of these lysines may have special regulatory significance. Other acetylation events, including histone H3K9 acetylation, are likely to result from the activities of the broad-specificity HAC1, HAC5, and HAC12 histone acetyltransferases. [source] Effects of trichostatin A on in vitro development and transgene function in somatic cell nuclear transfer embryos derived from transgenic Clawn miniature pig cellsANIMAL SCIENCE JOURNAL, Issue 5 2010Takehiro HIMAKI ABSTRACT The present study was carried out to examine the effects of post-activation treatment of trichostatin A (TSA), a histone deacetylase inhibitor, on in vitro development and transgene function of somatic cell nuclear transfer (SCNT) embryos derived from Clawn miniature pig embryonic fibroblast (PEF) transfected with a bacterial endo-,-galactosidase C gene (removal of the ,-galactosyl (Gal) epitope). SCNT embryos were incubated with or without TSA (50 or 100 nmol/L) after activation, cultured in vitro and assessed for cleavage, blastocyst formation and transgene function. The rate of blastocyst formation was significantly higher in SCNT embryos treated with 50 nmol/L TSA than that in control (P < 0.05), whereas the rate of cleavage and cell number of blastocyst did not differ. Following labelling with fluorescein isothiocyanate-labelled BS-I-B4 isolectin, the intensity of fluorescence observed on cell-surface was dramatically reduced in transgenic SCNT blastocyst in comparison with non-transgenic SCNT blastocyst. However, the reduction of ,-Gal epitope expression in transgenic SCNT blastocyst was not affected by TSA treatment. The results of this study showed that post-activation treatment with 50 nmol/L TSA is effective to improve in vitro developmental capacity of transgenic SCNT miniature pig embryos without the modification of transgene function. [source] Randomized sequential trial of valproic acid in amyotrophic lateral sclerosis,ANNALS OF NEUROLOGY, Issue 2 2009Sanne Piepers MD Objective To determine whether valproic acid (VPA), a histone deacetylase inhibitor that showed antioxidative and antiapoptotic properties and reduced glutamate toxicity in preclinical studies, is safe and effective in amyotrophic lateral sclerosis (ALS) using a sequential trial design. Methods Between April 2005 and January 2007, 163 ALS patients received VPA 1,500mg or placebo daily. Primary end point was survival. Secondary outcome measure was decline of functional status measured by the revised ALS Functional Rating Scale. Analysis was by intention to treat and according to a sequential trial design. This trial was registered with ClinicalTrials.gov (number NCT00136110). Results VPA did not affect survival (cumulative survival probability of 0.72 in the VPA group [standard error (SE), 0.06] vs 0.88 in the placebo group [SE, 0.04] at 12 months, and 0.59 in the VPA group [SE, 0.07] vs 0.68 in the placebo group [SE, 0.08] at 16 months) or the rate of decline of functional status. VPA intake did not cause serious adverse reactions. Interpretation Our finding that VPA, at a dose used in epilepsy, does not show a beneficial effect on survival or disease progression in patients with ALS has implications for future trials with histone deacetylase inhibitors in ALS and other neurodegenerative diseases. The use of a sequential trial design allowed inclusion of only half the number of patients required for a classic trial design and prevented patients from unnecessarily continuing potentially harmful study medication. Ann Neurol 2009;66:227,234 [source] Sustained improvement of spinal muscular atrophy mice treated with trichostatin a plus nutritionANNALS OF NEUROLOGY, Issue 4 2008Heather L. Narver VMD Early treatment with the histone deacetylase inhibitor, trichostatin A, plus nutritional support extended median survival of spinal muscular atrophy mice by 170%. Treated mice continued to gain weight, maintained stable motor function, and retained intact neuromuscular junctions long after trichostatin A was discontinued. In many cases, ultimate decline of mice appeared to result from vascular necrosis, raising the possibility that vascular dysfunction is part of the clinical spectrum of severe spinal muscular atrophy. Early spinal muscular atrophy disease detection and treatment initiation combined with aggressive ancillary care may be integral to the optimization of histone deacetylase inhibitor treatment in human patients. Ann Neurol 2008; 64:465,470 [source] Pharmacokinetics of a novel histone deacetylase inhibitor, apicidin, in ratsBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 2 2006Beom Soo Shin Abstract This study is the first report of the pharmacokinetics of a novel histone deacetylase inhibitor, apicidin, in rats after i.v. and oral administration. Apicidin was injected intravenously at doses of 0.5, 1.0, 2.0 and 4.0 mg/kg. The terminal elimination half-life (t1/2), systemic clearance (Cl) and steady-state volume of distribution (Vss) remained unaltered as a function of dose, with values in the range 0.8,1.1 h, 59.6,68.0 ml/min/kg and 2.4,2.7 l/kg, respectively. Whereas, the initial serum concentration (C0) and AUC increased linearly as the dose was increased. Taken together, the pharmacokinetics of apicidin were linear over the i.v. dose range studied. The extent of urinary and biliary excretion of apicidin was minimal (0.017%,0.020% and 0.049%±0.016%, respectively). Oral pharmacokinetic studies were conducted in fasting and non-fasting groups of rats at a dose of 10 mg/kg. The Tmax, Cl/F and Vz/F were in the range 0.9,1.1 h, 520.3,621.2 ml/min/kg and 67.6,84.4 l/kg, respectively. No significant difference was observed in the oral absorption profiles between the two groups of rats. Apicidin was poorly absorbed, with the absolute oral bioavailability of 19.3% and 14.2% in fasting and non-fasting rats. Copyright © 2005 John Wiley & Sons, Ltd. [source] Gene silencing of MIR22 in acute lymphoblastic leukaemia involves histone modifications independent of promoter DNA methylationBRITISH JOURNAL OF HAEMATOLOGY, Issue 1 2010Xiaoqing Li Summary Aberrant epigenetic regulation has recently been implicated in the downregulation of tumour suppressor microRNAs (miRNAs). Histone modification and DNA methylation can have different roles in gene silencing in cancer. To investigate whether histone modifications would contribute to the dysregulation of miRNAs in acute lymphoblastic leukaemia (ALL), the effect of a histone deacetylase inhibitor, trichostatin A (TSA), on miRNA expression profile was analysed by microarray assay in a precursor B-cell ALL cell line NALM-6. A total of 10 miRNAs were downregulated and 31 were upregulated significantly following TSA treatment. Among TSA-upregulated miRNAs, MIR22 is an extronic miRNA and resides in the second exon of the non-coding transcript MGC14376. Upregulation of MIR22 transcription was found in both NALM-6 cells and primary human ALL malignant cells treated with TSA. Whereas a CpG island was identified within the promoter element of MIR22, no promoter DNA methylation was detected in these cells. In contrast, accumulation of the repressive histone marker H3K27 trimethylation (H3K27triM) was indentified around the transcriptional start point of the gene, which was reduced by TSA treatment. Thus, accumulation of H3K27triM independent of promoter DNA methylation may be a novel epigenetic mechanism for MIR22 silencing in ALL. [source] Romidepsin (FK228), a potent histone deacetylase inhibitor, induces apoptosis through the generation of hydrogen peroxideCANCER SCIENCE, Issue 10 2010Hideki Mizutani Romidepsin (FK228) is a potent histone deacetylase (HDAC) inhibitor, which has a potent anticancer activity, but its molecular mechanism is unknown. We investigated the mechanism of FK228-induced apoptosis in the human leukemia cell line HL-60 and its hydrogen peroxide (H2O2)-resistant sub-clone, HP100, and the human colon cancer cell line Caco-2. Cytotoxicity and DNA ladder formation induced by FK228 could be detected in HL-60 cells after a 24-h incubation, whereas they could not be detected in HP100 cells. Trichostatin A (TSA), an HDAC inhibitor, induced DNA ladder formation in both HL-60 and HP100 cells. In contrast, FK228 inhibited HDAC activity in both HL-60 and HP100 cells to a similar extent. These findings suggest that FK228-induced apoptosis involves H2O2 -mediated pathways and that TSA-induced apoptosis does not. Flow cytometry revealed H2O2 formation and a change in mitochondrial membrane potential (,,m) in FK228-treated cells. FK228 also induced apoptosis in Caco-2 cells, which was prevented by N -acetyl-cysteine, suggesting that reactive oxygen species participate in apoptosis in various types of tumor cells. Interestingly, in a cell-free system, FK228 generated superoxide (O2,) in the presence of glutathione, suggesting that H2O2 is derived from dismutation of O2, produced through redox-cycle of FK228. Therefore, in addition to HDAC inhibition, H2O2 generated from FK228 may participate in its apoptotic effect. (Cancer Sci 2010;) [source] Potential efficacy of the oral histone deacetylase inhibitor vorinostat in a phase I trial in follicular and mantle cell lymphomaCANCER SCIENCE, Issue 1 2010Takashi Watanabe Vorinostat (suberoylanilide hydroxamic acid, SAHA, Zolinza) is a histone deacetylase inhibitor with clinical activity in cutaneous T-cell lymphoma (CTCL). A phase I trial of oral vorinostat was conducted in Japanese patients with malignant lymphoma. Vorinostat 100 or 200 mg was administered twice daily for 14 consecutive days followed by a 1-week rest interval. Of 10 patients enrolled, four had follicular lymphoma (FL), two mantle cell lymphoma (MCL), two diffuse large B-cell lymphoma, and two CTCL (median age, 60 years; median number of prior regimens, 3). Vorinostat was well tolerated up to 200 mg with only one of six patients developing a dose-limiting toxicity (DLT; Grade 3 anorexia/hypokalemia). Common Grade 3 events were reversible neutropenia (30%), thrombocytopenia, and hypermagnesemia (20% each). The median number of treatment cycles was five (range, 1,36); two patients were continuing treatment. The overall response rate was 40%, with two complete responses/unconfirmed (CRu) and one partial response among FL patients and one CRu among MCL patients. One FL patient maintained CRu for 18.0 months. The median time to achieve CRu among the three patients was 8 months. These data suggest that further investigations of vorinostat in non-Hodgkin lymphoma, focusing on FL and MCL, are warranted. (Cancer Sci 2009) [source] Aberrant methylation of the vascular endothelial growth factor receptor-1 gene in prostate cancerCANCER SCIENCE, Issue 6 2003Yasushi Yamada Transcriptional silencing of cancer-related genes by DNA methylation is observed in various cancers. To identify genes controlled by methylation in prostate cancer, we used cDNA microarray analysis to investigate gene expression in prostate cancer cell lines LNCaP and DU145 treated with a methyltransferase inhibitor alone or together with a histone deacetylase inhibitor. We detected significant changes (3.4,5.7%) in gene expression in prostate cancer cell lines with the drug treatments. Among the affected genes, that for the vascular endothelial growth factor receptor 1 (VEGFR-1) was re-expressed in LNCaP and DU145 after the drug treatments. Bisulfite sequencing revealed the promoter and exon 1 of the VEGFR-1 to be hypermethylated in the cell lines. These results support the idea that methylation is associated with loss of VEGFR-1 mRNA expression in prostate cancer cell lines. Combined bisulfite restriction analysis (COBRA) showed the gene to be methylated in 24 (38.1%) of 63 primary local prostate cancer samples, while in all 13 benign prostate samples it was not. These findings indicate that methylation of VEGFR-1 is related with prostatic carcinogenesis. [source] Differential effects of histone deacetylase inhibitors on phorbol ester- and TGF-,1 induced murine tissue inhibitor of metalloproteinases-1 gene expressionFEBS JOURNAL, Issue 8 2005David A. Young Expression of the tissue inhibitor of metalloproteinases-1 (Timp-1) gene can be induced by either phorbol myristate acetate (PMA) or transforming growth factor ,1 (TGF-,1), although the signalling pathways involved are not clearly defined. Canonically, histone deacetylase inhibitors (HDACi) such as trichostatin A (TSA) or sodium butyrate (NaB) increase total cellular histone acetylation and activate expression of susceptible genes. Remarkably, PMA and TGF-,1 stimulation of Timp-1 show a differential response to TSA or NaB. TSA or NaB potentiate PMA-induced Timp-1 expression but repress TGF-,1-induced Timp-1 expression. The repression of TGF-,1-induced Timp-1 by TSA was maximal at 5 ng·mL,1, while for the superinduction of PMA-induced Timp-1 expression, the maximal dose is >,500 ng·mL,1 TSA. A further HDACi, valproic acid, did not block TGF-,1-induced Timp-1 expression, demonstrating that different HDACs impact on the induction of Timp-1. For either PMA or TGF-,1 to induce Timp-1 expression, new protein synthesis is required, and the induction of AP-1 factors closely precedes that of Timp-1. The effects of the HDACi can be reiterated in transient transfection using Timp-1 promoter constructs. Mutation or deletion of the AP-1 motif (,59/,53) in the Timp-1 promoter diminishes PMA-induction of reporter constructs, however, the further addition of TSA still superinduces the reporter. In c-Jun,/, cells, PMA still stimulates Timp-1 expression, but TSA superinduction is lost. Transfection of a series of Timp-1 promoter constructs identified three regions through which TSA superinduces PMA-induced Timp-1 and we have demonstrated specific protein binding to two of these regions which contain either an avian erythroblastosis virus E26 (v-ets) oncogene homologue (Ets) or Sp1 binding motif. [source] Increased hepatotoxicity of tumor necrosis factor,related apoptosis-inducing ligand in diseased human liver,HEPATOLOGY, Issue 5 2007Xandra Volkmann Tumor necrosis factor,related apoptosis-inducing ligand (TRAIL) induces apoptosis in tumor cells but not in most normal cells and has therefore been proposed as a promising antitumor agent. Recent experiments suggested that isolated primary human hepatocytes but not monkey liver cells are susceptible to certain TRAIL agonists, raising concerns about the use of TRAIL in cancer treatment. Whether TRAIL indeed exerts hepatotoxicity in vivo and how this is influenced by chemotherapeutic drugs or liver disease are completely unknown. Employing different forms of recombinant TRAIL, we found that the cytokine can induce proapoptotic caspase activity in isolated human hepatocytes. However in marked contrast, these different TRAIL preparations induced little or no cytotoxicity when incubated with tissue explants of fresh healthy liver, an experimental model that may more faithfully mimic the in vivo situation. In healthy liver, TRAIL induced apoptosis only when combined with histone deacetylase inhibitors. Strikingly, however, TRAIL alone triggered massive apoptosis accompanied by caspase activation in tissue explants from patients with liver steatosis or hepatitis C viral infection. This enhanced sensitivity of diseased liver was associated with an increased expression of TRAIL receptors and up-regulation of proapoptotic Bcl-2 proteins. Conclusion: These results suggest that clinical trials should be performed with great caution when TRAIL is combined with chemotherapy or administered to patients with inflammatory liver diseases. (HEPATOLOGY 2007.) [source] The use of histone deacetylase inhibitor FK228 and DNA hypomethylation agent 5-azacytidine in human bladder cancer therapyINTERNATIONAL JOURNAL OF CANCER, Issue 8 2007Jose A. Karam Abstract The long-term disease-free survival in patients with metastatic transitional cell carcinoma (TCC) is still considerably low. Novel chemotherapeutic agents are needed to decrease the morbidity and mortality of TCC. In this study, we have evaluated several epigenetic modifiers for their therapeutic application in bladder cancer. Both histone deacetylase inhibitors (FK228, TSA) and DNA hypomethylating agent (5-Azacytidine) were tested using in vitro assays such as cell viability, cell cycle analysis and western blot to determine their mechanisms of action. Drug combination experiments were also designed to study any additive or synergistic effects of these agents. In addition, two bladder cancer xenograft models (one subcutaneous and one orthotopic) were employed to assess the therapeutic efficacy of these agents in vivo. Three agents exhibited various growth inhibitory effects on 5 different TCC cell lines in a dose- and time-dependent manner. In addition to G2/M cell cycle arrest, FK228 is more potent in inducting apoptosis than the two other single agents, and combination of both FK228 and 5-Aza further enhances this effect. p21 induction is closely associated with FK228 or TSA but not 5-Aza, which is mediated via p53-independent pathway. Consistent with in vitro results, FK228 exhibited a significant in vivo growth inhibition of TCC tumor in both subcutaneous and orthotopic xenograft models. FK228 is a potent chemotherapeutic agent for TCC in vivo with minimal undesirable side effects. The elevated p21 level mediated via p53 independent pathway is a hallmark of FK228 mechanism of action. © 2007 Wiley-Liss, Inc. [source] Chronic administration of valproic acid inhibits PC3 cell growth by suppressing tumor angiogenesis in vivoINTERNATIONAL JOURNAL OF UROLOGY, Issue 9 2007Dexuan Gao Aim: Chromatin remodeling agents such as histone deacetylase inhibitors have been shown to modulate gene expression in tumor cells and inhibit tumor growth and angiogenesis. We investigated the mechanisms of chronic valproic acid (VPA) inhibiting PC3 cell growth in the study. Methods: We established tumor xenografts of the PC3 cell line and investigated the effect of VPA chronic administration on tumor growth. Apoptosis in tumor tissue was measured using the TUNEL Detection Kit. We detected the effect of VPA chronic administration on histone acetylation; p21CIP1/WAF1 gene expression; vascular endothelial growth factor (VEGF) expression by reverse-transcription Polymerase Chain Reaction (PCR) analysis; immunohistochemistry; and Western Blotting. Result: In mouse models with established subcutaneous prostate (PC3), VPA treatment induced 70% inhibition of tumor growth without overt toxicity. Our result showed that chronic administration of VPA has an effect on tumor growth arrest and the effect was associated with increased histone acetylation, p21CIP1/WAF1 up-regulation, and VEGF down-regulation. Conclusion: We conclude that chronic VPA results in profound decreases in the proliferation of PC3 cells, not only by increasing histone H3 acetylation and up-regulating p21CIP1/WAF1 expression, but also by down-regulating VEGF. [source] Regulation of CYP1A2 by histone deacetylase inhibitors in mouse hepatocytesJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 3 2004Bohwan Jin Abstract Cytochrome P450 1A2 (CYP1A2) is constitutively expressed in the mouse liver, but the constitutive expression progressively declines to an undetectable level in isolated hepatocytes. In this study, CYP1A2 was induced in hepatocytes exposed to the histone deacetylase inhibitors trichostatin A (TSA) and sodium butyrate (SB), but only well after constitutive CYP1A2 expression was silenced. However, cotreatment with the arylhydrocarbon receptor (AhR) ligand 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD) and either TSA or SB reduced the induction of CYP1A2 with the same time course as TSA or SB increased its induction. These results suggest that histone modification is involved in CYP1A2 regulation in hepatocytes through pathways that are independent of AhR. © 2004 Wiley Periodicals, Inc. J Biochem Mol Toxicol 18:131,132, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20017 [source] Effects of histone deacetylase inhibitors on p55CDC/Cdc20 expression in HT29 cell lineJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 4 2006Giuseppe Iacomino Abstract In a previous work, taking advantage of the gene-array screening technology, we analysed the effects of histone deacetylase (HDAC) inhibitor sodium butyrate (NaBt), on gene transcription in HT29 human adenocarcinoma cell line. In this study, we focused our attention on p55CDC/Cdc20 gene, whose expression was dramatically reduced by NaBt treatment. Mammalian p55CDC/Cdc20 interacts with the anaphase promoting complex/cyclosome (APC/C), and is involved in regulating anaphase onset and late mitotic events. Using NaBt and trichostatin A (TSA), a member of the HDAC inhibitor family, we showed that both HDAC inhibitors totally downregulated p55CDC/Cdc20 transcription and expression. Cell cycle analysis demonstrated that NaBt arrested HT29 cells in G0/G1 phase, while TSA caused a double block in G0/G1 and G2/M phases. Moreover, p55CDC/Cdc20 showed maximal expression in S and G2/M phases of HT29 cell division cycle. Based on this evidence, and by means of specific cell cycle modulators, such as nocodazole and hydroxyurea, we demonstrated that both TSA and NaBt were responsible for loss of p55CDC/Cdc20 expression, but with different mechanisms of action. Taken together, these results suggest that targeting molecules involved in spindle mitotic checkpoint, such as p55CDC/Cdc20, might account for the high cytotoxicity of HDAC inhibitors versus malignant cells. J. Cell. Biochem. 99: 1122,1131, 2006. © 2006 Wiley-Liss, Inc. [source] Restoration of DNA-binding and growth-suppressive activity of mutant forms of p53 via a PCAF-mediated acetylation pathway,JOURNAL OF CELLULAR PHYSIOLOGY, Issue 2 2010Ricardo E. Perez Tumor-derived mutant forms of p53 compromise its DNA binding, transcriptional, and growth regulatory activity in a manner that is dependent upon the cell-type and the type of mutation. Given the high frequency of p53 mutations in human tumors, reactivation of the p53 pathway has been widely proposed as beneficial for cancer therapy. In support of this possibility p53 mutants possess a certain degree of conformational flexibility that allows for re-induction of function by a number of structurally different artificial compounds or by short peptides. This raises the question of whether physiological pathways for p53 mutant reactivation also exist and can be exploited therapeutically. The activity of wild-type p53 is modulated by various acetyl-transferases and deacetylases, but whether acetylation influences signaling by p53 mutant is still unknown. Here, we show that the PCAF acetyl-transferase is down-regulated in tumors harboring p53 mutants, where its re-expression leads to p53 acetylation and to cell death. Furthermore, acetylation restores the DNA-binding ability of p53 mutants in vitro and expression of PCAF, or treatment with deacetylase inhibitors, promotes their binding to p53-regulated promoters and transcriptional activity in vivo. These data suggest that PCAF-mediated acetylation rescues activity of at least a set of p53 mutations. Therefore, we propose that dis-regulation of PCAF activity is a pre-requisite for p53 mutant loss of function and for the oncogenic potential acquired by neoplastic cells expressing these proteins. Our findings offer a new rationale for therapeutic targeting of PCAF activity in tumors harboring oncogenic versions of p53. J. Cell. Physiol. 225: 394,405, 2010. © 2010 Wiley-Liss, Inc. [source] The emerging role of epigenetic modifications and chromatin remodeling in spinal muscular atrophyJOURNAL OF NEUROCHEMISTRY, Issue 6 2009Sebastian Lunke Abstract As the leading genetic cause for infantile death, Spinal Muscular Atrophy (SMA) has been extensively studied since its first description in the early 1890s. Though today much is known about the cause of the disease, a cure or effective treatment is not currently available. Recently the short chain fatty acid valproic acid, a drug used for decades in the management of epilepsy and migraine therapy, has been shown to elevate the levels of the essential survival motor neuron protein in cultured cells. In SMA mice, valproic acid diminished the severity of the disease phenotype. This effect was linked to the ability of the short chain fatty acid to suppress histone deacetylase activity and activate gene transcription. Since then, the study of different histone deacetylase inhibitors and their epigenetic modifying capabilities has been of high interest in an attempt to find potential candidates for effective treatment of SMA. In this review, we summarize the current knowledge about use of histone deacetylase inhibitors in SMA as well as their proposed effects on chromatin structure and discuss further implications for possible treatments of SMA arising from research examining epigenetic change. [source] New established melanoma cell lines: genetic and biochemical characterization of cell division cycleJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 1 2003A Vozza ABSTRACT Background Cancer might be envisaged as the result of a genetic process causing the unregulated proliferation of a given cell as well as its inability to undergo differentiation and/or apoptosis. Alterations of genes regulating cell division cycle appear to play a key role in the development of human cancer. Objective On the bases of the above considerations, we decided to establish new cell lines from human melanoma specimens, in order to analyse the molecular alterations in primary preparations of malignant cells. Results The present paper describes two new established cell lines and their genetic and biochemical features. Both the melanoma cell lines show inactivation of the cyclin-dependent kinase inhibitor gene, CDKN2A/p16INK4A, thus demostrating that this alteration occurs in primary human melanomas. No other alterations were observable when we investigated several different cell cycle genes including those encoding cyclins, cyclin-dependent kinases and cyclin-dependent kinase inhibitors. Analyses at protein level by means of immunoblotting confirmed the results obtained at the genetic level. Moreover, the inducibility of a pivotal cyclin-dependent kinase inhibitor gene, namely p21CIP1 gene, was obtained by treating the cells with histone deacetylase inhibitors, namely butyrate and phenylbutyrate. Conclusions Our results suggest a primary role of cyclin-dependent kinase inhibitor genes inactivation in the origin of human melanoma and allow the proposal of new therapeutic strategies based on the transcriptional activation of p21CIP1 gene. [source] Atypical presentations of Sweet's syndrome in patients with MDS/AML receiving combinations of hypomethylating agents with histone deacetylase inhibitors,AMERICAN JOURNAL OF HEMATOLOGY, Issue 10 2009Cristina Alencar No abstract is available for this article. [source] Randomized sequential trial of valproic acid in amyotrophic lateral sclerosis,ANNALS OF NEUROLOGY, Issue 2 2009Sanne Piepers MD Objective To determine whether valproic acid (VPA), a histone deacetylase inhibitor that showed antioxidative and antiapoptotic properties and reduced glutamate toxicity in preclinical studies, is safe and effective in amyotrophic lateral sclerosis (ALS) using a sequential trial design. Methods Between April 2005 and January 2007, 163 ALS patients received VPA 1,500mg or placebo daily. Primary end point was survival. Secondary outcome measure was decline of functional status measured by the revised ALS Functional Rating Scale. Analysis was by intention to treat and according to a sequential trial design. This trial was registered with ClinicalTrials.gov (number NCT00136110). Results VPA did not affect survival (cumulative survival probability of 0.72 in the VPA group [standard error (SE), 0.06] vs 0.88 in the placebo group [SE, 0.04] at 12 months, and 0.59 in the VPA group [SE, 0.07] vs 0.68 in the placebo group [SE, 0.08] at 16 months) or the rate of decline of functional status. VPA intake did not cause serious adverse reactions. Interpretation Our finding that VPA, at a dose used in epilepsy, does not show a beneficial effect on survival or disease progression in patients with ALS has implications for future trials with histone deacetylase inhibitors in ALS and other neurodegenerative diseases. The use of a sequential trial design allowed inclusion of only half the number of patients required for a classic trial design and prevented patients from unnecessarily continuing potentially harmful study medication. Ann Neurol 2009;66:227,234 [source] Inhibitors of Human Histone Deacetylase: Synthesis and Enzyme Assay of Hydroxamates with Piperazine LinkerARCHIV DER PHARMAZIE, Issue 3 2010Shubhashis Chakrabarty Abstract The histone deacetylase (HDAC) enzyme plays an important role in gene transcription. Inhibitors of histone deacetylases induce cell differentiation and suppress cell proliferation in tumor cells. Hydroxamates with rigid linker have displayed better inhibition profiles than those with linear and flexible aliphatic linkers. We have designed and synthesized several potential histone deacetylase inhibitors with a piperazine moiety in the linker region to test the effect of reduced linker flexibility. Inhibitors were evaluated for their inhibitory action on human HDAC3/NCoR2 and HDAC8. N -Hydroxycarboxamide derivatives (compounds 4a,d) were found to be better than N -hydroxyacetamide derivatives (compounds 6a,d) against HDAC8. Amongst the synthesized compounds, 4a (HDAC8, IC50: 3.15 ,M) with no substitution in the aryl cap was the most active and promising lead for further investigations. [source] Association between enhanced type I collagen expression and epigenetic repression of the FLI1 gene in scleroderma fibroblastsARTHRITIS & RHEUMATISM, Issue 7 2006Youngqing Wang Objective Scleroderma (systemic sclerosis; SSc) is an autoimmune disease characterized by vasculopathy and widespread organ fibrosis. Altered fibroblast function, both in vivo and in vitro, is well documented and illustrated by augmented synthesis and deposition of extracellular matrix proteins. We undertook this study to investigate the possibility that epigenetic mechanisms mediate the emergence and persistence of the altered SSc fibroblast phenotype. Methods The effects of DNA methyltransferase and histone deacetylase inhibitors on collagen expression and the level of epigenetic mediators in fibroblasts were examined. The effects of transient transfection of SSc fibroblasts with FLI1 gene and normal cells with FLI1 antisense construct on collagen expression were determined. The methylation status of the FLI1 promoter was tested in cultured cells and in SSc and normal skin biopsy specimens. Results Increased levels of epigenetic mediators in SSc fibroblasts were noted. The addition of epigenetic inhibitors to cell cultures normalized collagen expression in SSc fibroblasts. The augmented collagen synthesis by SSc fibroblasts was linked to epigenetic repression of the collagen suppressor gene FLI1. Heavy methylation of the CpG islands in the FLI1 promoter region was demonstrated in SSc fibroblasts and skin biopsy specimens. Conclusion The results of this study indicate that epigenetic mechanisms may mediate the fibrotic manifestations of SSc. The signal transduction leading to the SSc fibrotic phenotype appears to converge on DNA methylation and histone deacetylation at the FLI1 gene. [source] The NF (Nuclear factor)-,B inhibitor parthenolide interacts with histone deacetylase inhibitors to induce MKK7/JNK1-dependent apoptosis in human acute myeloid leukaemia cellsBRITISH JOURNAL OF HAEMATOLOGY, Issue 1 2010Yun Dai Summary Interactions between the nuclear factor (NF)-,B inhibitor parthenolide and the pan-histone deacetylase inhibitors (HDACIs) vorinostat and LBH589 were investigated in human acute myeloid leukaemia (AML) cells, including primary AML blasts. Co-administration of parthenolide blocked HDACI-mediated phosphorylation/activation of IKK and RelA/p65 in association with increased JNK1 activation in various AML cell types. These events were accompanied by an increase in apoptosis in multiple AML cell lines (e.g. U937, HL-60, NB4, MV-4-11, and MOLM-13). Significantly, parthenolide also increased HDACI-mediated cell death in haematopoietic cells transduced with the MLL - MLLT1 fusion gene, which exhibit certain leukaemia-initiating cell characteristics, as well as primary AML blasts. Exposure to parthenolide/HDACI regimens clearly inhibited the growth of AML-colony-forming units but was relatively sparing toward normal haematopoietic progenitors. Notably, blockade of c-Jun N-terminal kinase (JNK) signalling by either pharmacological inhibitors or genetic means (e.g. dominant-negative JNK1 or JNK1 shRNA) diminished parthenolide/HDACI-mediated lethality. Moreover, dominant-negative MKK7, but not dominant-negative MKK4/SEK1, blocked JNK1 activation and apoptosis induced by parthenolide/HDACI regimens. Together, these findings indicate that parthenolide potentiates HDACI lethality in human AML cells through a process involving NF-,B inhibition and subsequent MKK7-dependent activation of the SAPK/JNK pathway. They also raise the possibility that this strategy may target leukaemic progenitor cells. [source] A phase I study of vorinostat in combination with idarubicin in relapsed or refractory leukaemiaBRITISH JOURNAL OF HAEMATOLOGY, Issue 1 2010Tapan M. Kadia Summary Histone deacetylase inhibitors (HDACi) affect chromatin remodelling and modulate the expression of aberrantly silenced genes. HDACi have single-agent clinical activity in haematological malignancies and have synergistic anti-leukaemia activity when combined with anthracyclines in vitro. We conducted a two-arm, parallel Phase I trial to investigate two schedules of escalating doses of vorinostat (Schedule A: thrice daily (TID) for 14 d; B: TID for 3 d) in combination with a fixed dose of idarubicin in patients with refractory leukaemia. Of the 41 patients enrolled, 90% had acute myeloid leukaemia, with a median of 3 prior therapies. Seven responses (17%) were documented (two complete response (5%), one complete response without platelet recovery (2·5%), and four marrow responses). The 3-d schedule of vorinostat was better tolerated than the 14-d schedule. The maximum tolerated dose for vorinostat was defined as 400 mg TID for 3 d. The most common grade 3 and 4 toxicities included mucositis, fatigue and diarrhoea. Correlative studies demonstrated histone acetylation in patients on therapy and modulation of CDKN1A and TOP2A (topoisomerase II) gene expression. Pharmacokinetic analysis confirmed a dose-related elevation in plasma vorinostat concentrations. The combination of vorinostat and idarubicin is generally tolerable and active in patients with advanced leukaemia and should be studied in the front-line setting. [source] Laboratory correlates for a phase II trial of romidepsin in cutaneous and peripheral T-cell lymphomaBRITISH JOURNAL OF HAEMATOLOGY, Issue 2 2010Susan E. Bates Summary Romidepsin has shown promise in the treatment of T-cell lymphomas, and so we evaluated molecular endpoints gathered from 61 patients enrolled on a phase II trial of romidepsin in cutaneous and peripheral T-cell lymphoma at the National Institutes of Health. The endpoints included histone H3 acetylation and ABCB1 gene expression in peripheral blood mononuclear cells (PBMCs); ABCB1 gene expression in tumour biopsy samples; and blood fetal haemoglobin levels (HbF), all of which were increased following romidepsin treatment. The fold increase in histone acetylation in PBMCs at 24 h was weakly to moderately well correlated with the pharmacokinetic parameters Cmax and area under the curve (AUC)last (, = 0·37, P = 0·03 and , = 0·36, P = 0·03 respectively) and inversely associated with clearance (, = ,0·44; P = 0·03). Histone acetylation in PBMCs at 24 h was associated with response (P = 0·026) as was the increase in fetal haemoglobin (P = 0·014); this latter association may be due to the longer on-study duration for patients with disease response. Together, these results suggest that pharmacokinetics may be an important determinant of response to histone deacetylase inhibitors (HDIs) , the association with histone acetylation in PBMCs at 24 h is consistent with a hypothesis that potent HDIs are needed for a critical threshold of drug exposure and durable activity. [source] Human ovarian carcinoma cells: Histone deacetylase inhibitors exhibit antiproliferative activity and potently induce apoptosisCANCER, Issue 12 2004Noriyuki Takai M.D., Ph.D. Abstract BACKGROUND Histone deacetylase inhibitors (HDACIs) can inhibit proliferation, stimulate apoptosis, and induce cell cycle arrest in malignant cells. METHODS The authors investigated the effects of four HDACIs on nine ovarian carcinoma cell lines in vitro and in vivo. Ovarian carcinoma cells were treated with a variety of HDACIs, and their effects on cell growth, the cell cycle, apoptosis, and related events were investigated. The ability of valproic acid (VPA) to inhibit the growth of ovarian tumors in immunodeficient mice was also assessed. RESULTS Clonogenic assays showed that all ovarian carcinoma cell lines were sensitive to the growth-inhibitory effects of the HDACIs. Cell cycle analysis indicated that their exposure to HDACIs decreased the proportion of cells in S phase and increased the proportion of cells in the G0/G1 and/or G2/M phases of the cell cycle. Terminal deoxynucleotidyltransferase-mediated uridine triphosphate end-labeling assays demonstrated that HDACIs induced apoptosis, which occurred in concert with alterations in the expression of genes related to apoptosis, cell growth, and malignant phenotype, including the activation of caspase-9 and caspase-3. Chromatin immunoprecipitation analysis revealed a notable increase in levels of acetylated histones associated with the p21 promoter after treatment with suberoylanilide bishydroxamine. In addition, in experiments involving nude mice, VPA significantly inhibited human ovarian tumor growth without toxic side effects. CONCLUSIONS The results of the current study suggest that HDACIs may be particularly effective in the treatment of ovarian tumors. Cancer 2004. © 2004 American Cancer Society. [source] | |||||||||||||||||||||||||||||||