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  • MMP and TIMP expression in quiescent, dividing, and differentiating human lens cells. 17724206

    Matrix metalloproteinases (MMPs) and the tissue inhibitors of the MMPs (TIMPs) have been implicated in lens differentiation, growth, remodeling, and cataract. Hence, a gene expression analysis was undertaken in epithelial and fiber cells dissected from clear human donor lenses.The human lens was dissected into three regions: anterior epithelial, equatorial, and fiber cells. Primary lens cell cultures were also analyzed. cDNA was generated by reverse transcription of the mRNA portion of the total RNA isolated from each sample. Gene expression data were generated using quantitative real-time reverse transcription PCR. Data were analyzed in terms of cycle threshold number (C(T)) and were normalized to endogenous 18S expression. Western blot analyses were carried out to confirm the presence of two critical MMPs.Anterior and equatorial samples were uncontaminated by fiber cells because they showed high expression of alpha-crystallin genes but low expression of beta- and gamma-crystallins. The fibers had high expression of these genes and of MIP. MMP genes were expressed at uniformly low levels in the native tissues except for MMP-14 and -15 (MT1- and MT2-MMP, respectively). In fact, MT1-MMP declined in expression from the anterior epithelium to fibers, whereas MT2-MMP increased. The presence of MT1 and MT2-MMP proforms and faster migrating bands, indicating processed or activated forms, was confirmed at the protein level. TIMP genes were uniformly highly expressed in native tissues, with TIMP-3 having the highest expression in the epithelial tissues and TIMP-2 in the fibers. MMP expression was generally elevated in both sets of cultured cells, including MMP-2 and -9. TIMP genes were also relatively highly expressed in the cultured cells.MMP expression is generally well regulated in native tissues, with relatively low expression of MMPs and high expression of TIMPs. Membrane-type MMPs (MT1 and 2-MMPs) were the most highly expressed; this is important in a tissue with relatively high membrane content but low extracellular space. The striking reciprocal patterns of expression of MT1-MMP and MT2-MMP indicate that these enzymes are of particular significance in lens function.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Activity of PXD101, a histone deacetylase inhibitor, in preclinical ovarian cancer studies. 16928830

    Histone deacetylase inhibitors represent a promising new class of anticancer agents. In the current investigation, we examined the activity of PXD101, a potent histone deacetylase inhibitor, used alone or in combination with clinically relevant chemotherapeutics (docetaxel, paclitaxel, and carboplatin), in preclinical in vitro and in vivo models of ovarian cancer. In vitro activity was examined in ovarian cancer and multidrug-resistant cell lines grown in monolayer culture, and in primary clinical ovarian cancer specimens grown in three-dimensional organoid culture. PXD101 was found to inhibit in vitro cancer cell growth at sub- to low micromolar IC(50) potency, exhibited synergistic activity when used in combination with relevant chemotherapeutics, and effectively inhibited the growth of multidrug-resistant cells. In vivo, PXD101 displayed single-agent antitumor activity on human A2780 ovarian cancer s.c. xenografts which was enhanced via combination therapy with carboplatin. In support of these findings, PXD101 was shown to increase the acetylation of alpha-tubulin induced by docetaxel and the phosphorylation of H2AX induced by carboplatin. Taken together, these results support the clinical evaluation of PXD101 used alone or in combination therapy for the treatment of ovarian cancer.
    Tipo de documento:
    Referencia
    Referencia del producto:
    3301
    Nombre del producto:
    LIGHT DIAGNOSTICS™ Coxsackievirus A9 Reagent, ~25 tests, included in kit #3350

  • Delayed toxicity associated with soluble anthrax toxin receptor decoy-Ig fusion protein treatment. 22511955

    Soluble receptor decoy inhibitors, including receptor-immunogloubulin (Ig) fusion proteins, have shown promise as candidate anthrax toxin therapeutics. These agents act by binding to the receptor-interaction site on the protective antigen (PA) toxin subunit, thereby blocking toxin binding to cell surface receptors. Here we have made the surprising observation that co-administration of receptor decoy-Ig fusion proteins significantly delayed, but did not protect, rats challenged with anthrax lethal toxin. The delayed toxicity was associated with the in vivo assembly of a long-lived complex comprised of anthrax lethal toxin and the receptor decoy-Ig inhibitor. Intoxication in this system presumably results from the slow dissociation of the toxin complex from the inhibitor following their prolonged circulation. We conclude that while receptor decoy-Ig proteins represent promising candidates for the early treatment of B. anthracis infection, they may not be suitable for therapeutic use at later stages when fatal levels of toxin have already accumulated in the bloodstream.
    Tipo de documento:
    Referencia
    Referencia del producto:
    LSK2ABA20

  • Peptide inhibitors disrupt the serotonin 5-HT2C receptor interaction with phosphatase and tensin homolog to allosterically modulate cellular signaling and behavior. 23345234

    Serotonin (5-hydroxytryptamine; 5-HT) signaling through the 5-HT(2C) receptor (5-HT(2C)R) is essential in normal physiology, whereas aberrant 5-HT(2C)R function is thought to contribute to the pathogenesis of multiple neural disorders. The 5-HT(2C)R interacts with specific protein partners, but the impact of such interactions on 5-HT(2C)R function is poorly understood. Here, we report convergent cellular and behavioral data that the interaction between the 5-HT(2C)R and protein phosphatase and tensin homolog (PTEN) serves as a regulatory mechanism to control 5-HT(2C)R-mediated biology but not that of the closely homologous 5-HT(2A)R. A peptide derived from the third intracellular loop of the human 5-HT(2C)R [3L4F (third loop, fourth fragment)] disrupted the association, allosterically augmented 5-HT(2C)R-mediated signaling in live cells, and acted as a positive allosteric modulator in rats in vivo. We identified the critical residues within an 8 aa fragment of the 3L4F peptide that maintained efficacy (within the picomolar range) in live cells similar to that of the 3L4F peptide. Last, molecular modeling identified key structural features and potential interaction sites of the active 3L4F peptides against PTEN. These compelling data demonstrate the specificity and importance of this protein assembly in cellular events and behaviors mediated by 5-HT(2C)R signaling and provide a chemical guidepost to the future development of drug-like peptide or small-molecule inhibitors as neuroprobes to study 5-HT(2C)R allostery and therapeutics for 5-HT(2C)R-mediated disorders.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Nuclear levels and patterns of histone H3 modification and HP1 proteins after inhibition of histone deacetylases. 16254244

    The effects of the histone deacetylase inhibitors (HDACi) trichostatin A (TSA) and sodium butyrate (NaBt) were studied in A549, HT29 and FHC human cell lines. Global histone hyperacetylation, leading to decondensation of interphase chromatin, was characterized by an increase in H3(K9) and H3(K4) dimethylation and H3(K9) acetylation. The levels of all isoforms of heterochromatin protein, HP1, were reduced after HDAC inhibition. The observed changes in the protein levels were accompanied by changes in their interphase patterns. In control cells, H3(K9) acetylation and H3(K4) dimethylation were substantially reduced to a thin layer at the nuclear periphery, whereas TSA and NaBt caused the peripheral regions to become intensely acetylated at H3(K9) and dimethylated at H3(K4). The dispersed pattern of H3(K9) dimethylation was stable even at the nuclear periphery of HDACi-treated cells. After TSA and NaBt treatment, the HP1 proteins were repositioned more internally in the nucleus, being closely associated with interchromatin compartments, while centromeric heterochromatin was relocated closer to the nuclear periphery. These findings strongly suggest dissociation of HP1 proteins from peripherally located centromeres in a hyperacetylated and H3(K4) dimethylated environment. We conclude that inhibition of histone deacetylases caused dynamic reorganization of chromatin in parallel with changes in its epigenetic modifications.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Oral administration of the pimelic diphenylamide HDAC inhibitor HDACi 4b is unsuitable for chronic inhibition of HDAC activity in the CNS in vivo. 22973455

    Histone deacetylase (HDAC) inhibitors have received considerable attention as potential therapeutics for a variety of cancers and neurological disorders. Recent publications on a class of pimelic diphenylamide HDAC inhibitors have highlighted their promise in the treatment of the neurodegenerative diseases Friedreich's ataxia and Huntington's disease, based on efficacy in cell and mouse models. These studies' authors have proposed that the unique action of these compounds compared to hydroxamic acid-based HDAC inhibitors results from their unusual slow-on/slow-off kinetics of binding, preferentially to HDAC3, resulting in a distinctive pharmacological profile and reduced toxicity. Here, we evaluate the HDAC subtype selectivity, cellular activity, absorption, distribution, metabolism and excretion (ADME) properties, as well as the central pharmacodynamic profile of one such compound, HDACi 4b, previously described to show efficacy in vivo in the R6/2 mouse model of Huntington's disease. Based on our data reported here, we conclude that while the in vitro selectivity and binding mode are largely in agreement with previous reports, the physicochemical properties, metabolic and p-glycoprotein (Pgp) substrate liability of HDACi 4b render this compound suboptimal to investigate central Class I HDAC inhibition in vivo in mouse per oral administration. A drug administration regimen using HDACi 4b dissolved in drinking water was used in the previous proof of concept study, casting doubt on the validation of CNS HDAC3 inhibition as a target for the treatment of Huntington's disease. We highlight physicochemical stability and metabolic issues with 4b that are likely intrinsic liabilities of the benzamide chemotype in general.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Multiple mechanisms induce transcriptional silencing of a subset of genes, including oestrogen receptor alpha, in response to deacetylase inhibition by valproic acid and ... 15870696

    Valproate (VPA) and trichostatin A (TSA), inhibitors of zinc-dependent deacetylase activity, induce reduction in the levels of mRNA encoding oestrogen receptor-alpha (ERalpha), resulting in subsequent clearance of ERalpha protein from breast and ovarian cell lines. Inhibition of oestrogen signalling may account for the endocrine disorders, menstrual abnormalities, osteoporosis and weight gain that occur in a proportion of women treated with VPA for epilepsy or for bipolar mood disorder. Transcriptome profiling revealed that VPA and TSA also modulate the expression of, among others, key regulatory components of the cell cycle. Meta-analysis of genes directly responsive to oestrogen indicates that VPA and TSA have a generally antioestrogenic profile in ERalpha positive cells. Concomitant treatment with cycloheximide prevented most of these changes in gene expression, including downregulation of ERalpha mRNA, indicating that a limited number of genes signal a hyperacetylated state within cells. Three members of the NAD-dependent deacetylases, the sirtuins, are upregulated by VPA and by TSA and sirtuin activity contributes to loss of ERalpha expression. However, prolonged inhibition of the sirtuins by sirtinol also induces loss of ERalpha from cells. Mechanistically, we show that VPA invokes reversible promoter shutoff of the ERalpha, pS2 and cyclin D1 promoters, by inducing recruitment of methyl cytosine binding protein 2 (MeCP2) with concomitant exclusion of the maintenance methylase DNMT1. Furthermore, we demonstrate that, in the presence of VPA, local DNA methylation, deacetylation and demethylation of activated histones and recruitment of inhibitory complexes occurs on the pS2 promoter.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • HDAC8, A Potential Therapeutic Target for the Treatment of Malignant Peripheral Nerve Sheath Tumors (MPNST). 26200462

    HDAC isoform-specific inhibitors may improve the therapeutic window while limiting toxicities. Developing inhibitors against class I isoforms poses difficulties as they share high homology among their catalytic sites; however, HDAC8 is structurally unique compared to other class I isoforms. HDAC8 inhibitors are novel compounds and have affinity for class I HDAC isoforms demonstrating anti-cancer effects; little is known about their activity in malignant peripheral nerve sheath tumors (MPNST). Recently, we demonstrated anti-MPNST efficacy of HDAC8i in human and murine-derived MPNST pre-clinical models; we now seek to consider the potential therapeutic inhibition of HDAC8 in MPNST.Four Human MPNST cell lines, a murine-derived MPNST cell line, and two HDAC8 inhibitors (PCI-34051, PCI-48012; Pharmacyclics, Inc. Sunnyvale, CA) were studied. Proliferation was determined using MTS and clonogenic assays. Effects on cell cycle were determined via PI FACS analysis; effects on apoptosis were determined using Annexin V-PI FACS analysis and cleaved caspase 3 expression. In vivo growth effects of HDAC8i were evaluated using MPNST xenograft models. 2D gel electrophoresis and mass spectrometry were used to identify potential HDAC8 deacetylation substrates.HDAC8i induced cell growth inhibition and marked S-phase cell cycle arrest in human and murine-derived MPNST cells. Relative to control, HDAC8i induced apoptosis in both human and murine-derived MPNST cells. HDAC8i exhibited significant effects on MPNST xenograft growth (p=0.001) and tumor weight (p=0.02). Four potential HDAC8 substrate targets were identified using a proteomic approach: PARK7, HMGB1, PGAM1, PRDX6.MPNST is an aggressive sarcoma that is notoriously therapy-resistant, hence the urgent need for improved anti-MPNST therapies. HDAC8 inhibition may be useful for MPNST by improving efficacy while limiting toxicities as compared to pan-HDACis.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Histone deacetylase (HDAC) inhibitor activation of p21WAF1 involves changes in promoter-associated proteins, including HDAC1. 14734806

    Histone deacetylase (HDAC) inhibitors (HDACi) cause cancer cell growth arrest and/or apoptosis in vivo and in vitro. The HDACi suberoylanilide hydroxamic acid (SAHA) is in phase I/II clinical trials showing significant anticancer activity. Despite wide distribution of HDACs in chromatin, SAHA alters the expression of few genes in transformed cells. p21(WAF1) is one of the most commonly induced. SAHA does not alter the expression of p27(KIPI), an actively transcribed gene, or globin, a silent gene, in ARP-1 cells. Here we studied SAHA-induced changes in the p21(WAF1) promoter of ARP-1 cells to better understand the mechanism of HDACi gene activation. Within 1 h, SAHA caused modifications in acetylation and methylation of core histones and increased DNase I sensitivity and restriction enzyme accessibility in the p21(WAF1) promoter. These changes did not occur in the p27(KIPI) or epsilon-globin gene-related histones. The HDACi caused a marked decrease in HDAC1 and Myc and an increase in RNA polymerase II in proteins bound to the p21(WAF1) promoter. Thus, this study identifies effects of SAHA on p21(WAF1)-associated proteins that explain, at least in part, the selective effect of HDACi in altering gene expression.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo

  • Glyoxalase-I is a novel target against Bcr-Abl+ leukemic cells acquiring stem-like characteristics in a hypoxic environment. 20139893

    Abl tyrosine kinase inhibitors (TKIs) such as imatinib and dasatinib are ineffective against Bcr-Abl(+) leukemic stem cells. Thus, the identification of novel agents that are effective in eradicating quiescent Bcr-Abl(+) stem cells is needed to cure leukemias caused by Bcr-Abl(+) cells. Human Bcr-Abl(+) cells engrafted in the bone marrow of immunodeficient mice survive under severe hypoxia. We generated two hypoxia-adapted (HA)-Bcr-Abl(+) sublines by selection in long-term hypoxic cultures (1.0% O(2)). Interestingly, HA-Bcr-Abl(+) cells exhibited stem cell-like characteristics, including more cells in a dormant, increase of side population fraction, higher beta-catenin expression, resistance to Abl TKIs, and a higher transplantation efficiency. Compared with the respective parental cells, HA-Bcr-Abl(+) cells had higher levels of protein and higher enzyme activity of glyoxalase-I (Glo-I), an enzyme that detoxifies methylglyoxal, a cytotoxic by-product of glycolysis. In contrast to Abl TKIs, Glo-I inhibitors were much more effective in killing HA-Bcr-Abl(+) cells both in vitro and in vivo. These findings indicate that Glo-I is a novel molecular target for treatment of Bcr-Abl(+) leukemias, and, in particular, Abl TKI-resistant quiescent Bcr-Abl(+) leukemic cells that have acquired stem-like characteristics in the process of adapting to a hypoxic environment.
    Tipo de documento:
    Referencia
    Referencia del producto:
    Múltiplo
    Nombre del producto:
    Múltiplo