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ABSTRACT: Pompe disease is a lysosomal storage disease (LSD) caused by a deficiency in the lysosomal enzyme acid alpha-glucosidase. In several LSDs, enzyme inhibitors have been used as small molecule chaperones to facilitate and increase the translocation of mutant protein from the endoplasmic reticulum to the lysosome. Enzyme activators with chaperone activity would be even more desirable as they would not inhibit the enzyme after translocation and might potentiate the activity of the enzyme that is successfully translocated. Herein we report our initial findings of a new series of acid alpha-glucosidase activators.
European journal of medicinal chemistry 05/2010; 45(5):1880-97. · 3.27 Impact Factor
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ABSTRACT: Nuclear factor-kappa B (NF-kappaB) is a transcription factor that plays a critical role across many cellular processes including embryonic and neuronal development, cell proliferation, apoptosis, and immune responses to infection and inflammation. Dysregulation of NF-kappaB signaling is associated with inflammatory diseases and certain cancers. Constitutive activation of NF-kappaB signaling has been found in some types of tumors including breast, colon, prostate, skin and lymphoid, hence therapeutic blockade of NF-kappaB signaling in cancer cells provides an attractive strategy for the development of anticancer drugs. To identify small molecule inhibitors of NF-kappaB signaling, we screened approximately 2800 clinically approved drugs and bioactive compounds from the NIH Chemical Genomics Center Pharmaceutical Collection (NPC) in a NF-kappaB mediated beta-lactamase reporter gene assay. Each compound was tested at fifteen different concentrations in a quantitative high throughput screening format. We identified nineteen drugs that inhibited NF-kappaB signaling, with potencies as low as 20 nM. Many of these drugs, including emetine, fluorosalan, sunitinib malate, bithionol, narasin, tribromsalan, and lestaurtinib, inhibited NF-kappaB signaling via inhibition of IkappaBalpha phosphorylation. Others, such as ectinascidin 743, chromomycin A3 and bortezomib utilized other mechanisms. Furthermore, many of these drugs induced caspase 3/7 activity and had an inhibitory effect on cervical cancer cell growth. Our results indicate that many currently approved pharmaceuticals have previously unappreciated effects on NF-kappaB signaling, which may contribute to anticancer therapeutic effects. Comprehensive profiling of approved drugs provides insight into their molecular mechanisms, thus providing a basis for drug repurposing.
Biochemical pharmacology 05/2010; 79(9):1272-80. · 4.25 Impact Factor
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ABSTRACT: Activation of G(q) protein-coupled receptors can be monitored by measuring the increase in intracellular calcium with fluorescent dyes. Recent advances in fluorescent kinetic plate readers and liquid-handling technology have made it possible to follow these transient changes in intracellular calcium in a 1,536-well plate format for high-throughput screening (HTS). Here, we have applied the latest generation of fluorescence kinetic plate readers to multiplex the agonist and antagonist screens of a G protein-coupled receptor (GPCR). This multiplexed assay format provides an efficient and cost-effective method for HTS of G(q)-coupled GPCR targets.
Assay and Drug Development Technologies 03/2010; 8(3):367-79. · 1.73 Impact Factor
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Matthew B Boxer,
Jian-kang Jiang,
Matthew G Vander Heiden,
Min Shen,
Amanda P Skoumbourdis,
Noel Southall,
Henrike Veith,
William Leister, Christopher P Austin,
Hee Won Park,
James Inglese,
Lewis C Cantley,
Douglas S Auld,
Craig J Thomas
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ABSTRACT: The metabolism of cancer cells is altered to support rapid proliferation. Pharmacological activators of a tumor cell specific pyruvate kinase isozyme (PKM2) may be an approach for altering the classic Warburg effect characteristic of aberrant metabolism in cancer cells yielding a novel antiproliferation strategy. In this manuscript, we detail the discovery of a series of substituted N,N'-diarylsulfonamides as activators of PKM2. The synthesis of numerous analogues and the evaluation of structure-activity relationships are presented as well as assessments of mechanism and selectivity. Several agents are found that have good potencies and appropriate solubility for use as chemical probes of PKM2 including 55 (AC(50) = 43 nM, maximum response = 84%; solubility = 7.3 microg/mL), 56 (AC(50) = 99 nM, maximum response = 84%; solubility = 5.7 microg/mL), and 58 (AC(50) = 38 nM, maximum response = 82%; solubility = 51.2 microg/mL). The small molecules described here represent first-in-class activators of PKM2.
Journal of Medicinal Chemistry 12/2009; 53(3):1048-55. · 4.80 Impact Factor
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Menghang Xia,
Kun Bi,
Ruili Huang,
Ming-Hsuang Cho,
Srilatha Sakamuru,
Susanne C Miller,
Hua Li,
Yi Sun,
John Printen, Christopher P Austin,
James Inglese
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ABSTRACT: Hypoxia-inducible factor-1 (HIF-1) is the major hypoxia-regulated transcription factor that regulates cellular responses to low oxygen environments. HIF-1 is composed of two subunits: hypoxia-inducible HIF-1alpha and constitutively-expressed HIF-1beta. During hypoxic conditions, HIF-1alpha heterodimerizes with HIF-1beta and translocates to the nucleus where the HIF-1 complex binds to the hypoxia-response element (HRE) and activates expression of target genes implicated in cell growth and survival. HIF-1alpha protein expression is elevated in many solid tumors, including those of the cervix and brain, where cells that are the greatest distance from blood vessels, and therefore the most hypoxic, express the highest levels of HIF-1alpha. Therapeutic blockade of the HIF-1 signaling pathway in cancer cells therefore provides an attractive strategy for development of anticancer drugs. To identify small molecule inhibitors of the HIF-1 pathway, we have developed a cell-based reporter gene assay and screened a large compound library by using a quantitative high-throughput screening (qHTS) approach.
The assay is based upon a beta-lactamase reporter under the control of a HRE. We have screened approximate 73,000 compounds by qHTS, with each compound tested over a range of seven to fifteen concentrations. After qHTS we have rapidly identified three novel structural series of HIF-1 pathway Inhibitors. Selected compounds in these series were also confirmed as inhibitors in a HRE beta-lactamase reporter gene assay induced by low oxygen and in a VEGF secretion assay. Three of the four selected compounds tested showed significant inhibition of hypoxia-induced HIF-1alpha accumulation by western blot analysis.
The use of beta-lactamase reporter gene assays, in combination with qHTS, enabled the rapid identification and prioritization of inhibitors specific to the hypoxia induced signaling pathway.
Molecular Cancer 12/2009; 8:117. · 3.99 Impact Factor
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Bryan T Mott,
Cordelle Tanega,
Min Shen,
David J Maloney,
Paul Shinn,
William Leister,
Juan J Marugan,
James Inglese, Christopher P Austin,
Tom Misteli,
Douglas S Auld,
Craig J Thomas
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ABSTRACT: A series of substituted 6-arylquinazolin-4-amines were prepared and analyzed as inhibitors of Clk4. Synthesis, structure-activity relationships and the selectivity of a potent analogue against a panel of 402 kinases are presented. Inhibition of Clk4 by these agents at varied concentrations of assay substrates (ATP and receptor peptide) highly suggests that this chemotype is an ATP competitive inhibitor. Molecular docking provides further evidence that inhibition is the result of binding at the kinase hinge region. Selected compounds represent novel tools capable of potent and selective inhibition of Clk1, Clk4, and Dyrk1A.
Bioorganic & medicinal chemistry letters 12/2009; 19(23):6700-5. · 2.65 Impact Factor
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ABSTRACT: The perceived and actual burden of false positives in high-throughput screening has received considerable attention; however, few studies exist on the contributions of distinct mechanisms of nonspecific effects like chemical reactivity, assay signal interference, and colloidal aggregation. Here, we analyze the outcome of a screen of 197861 diverse compounds in a concentration-response format against the cysteine protease cruzain, a target expected to be particularly sensitive to reactive compounds, and using an assay format with light detection in the short-wavelength region where significant compound autofluorescence is typically encountered. Approximately 1.9% of all compounds screened were detergent-sensitive inhibitors. The contribution from autofluorescence and compounds bearing reactive functionalities was dramatically lower: of all hits, only 1.8% were autofluorescent and 1.5% contained reactive or undesired functional groups. The distribution of false positives was relatively constant across library sources. The simple step of including detergent in the assay buffer suppressed the nonspecific effect of approximately 93% of the original hits.
Journal of Medicinal Chemistry 11/2009; 53(1):37-51. · 4.80 Impact Factor
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Bryan T Mott,
Rafaela S Ferreira,
Anton Simeonov,
Ajit Jadhav,
Kenny Kean-Hooi Ang,
William Leister,
Min Shen,
Julia T Silveira,
Patricia S Doyle,
Michelle R Arkin,
James H McKerrow,
James Inglese, Christopher P Austin,
Craig J Thomas,
Brian K Shoichet,
David J Maloney
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ABSTRACT: Trypanosoma cruzi and Trypanosoma brucei are parasites that cause Chagas' disease and African sleeping sickness, respectively. Both parasites rely on essential cysteine proteases for survival: cruzain for T. cruzi and TbCatB/rhodesain for T. brucei. A recent quantitative high-throughput screen of cruzain identified triazine nitriles, which are known inhibitors of other cysteine proteases, as reversible inhibitors of the enzyme. Structural modifications detailed herein, including core scaffold modification from triazine to purine, improved the in vitro potency against both cruzain and rhodesain by 350-fold, while also gaining activity against T. brucei parasites. Selected compounds were screened against a panel of human cysteine and serine proteases to determine selectivity, and a cocrystal was obtained of our most potent analogue bound to cruzain.
Journal of Medicinal Chemistry 11/2009; 53(1):52-60. · 4.80 Impact Factor
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Henrike Veith,
Noel Southall,
Ruili Huang,
Tim James,
Darren Fayne,
Natalia Artemenko,
Min Shen,
James Inglese, Christopher P Austin,
David G Lloyd,
Douglas S Auld
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ABSTRACT: The cytochrome P450 (CYP) gene family catalyzes drug metabolism and bioactivation and is therefore relevant to drug development. We determined potency values for 17,143 compounds against five recombinant CYP isozymes (1A2, 2C9, 2C19, 2D6 and 3A4) using an in vitro bioluminescent assay. The compounds included libraries of US Food and Drug Administration (FDA)-approved drugs and screening libraries. We observed cross-library isozyme inhibition (30-78%) with important differences between libraries. Whereas only 7% of the typical screening library was inactive against all five isozymes, 33% of FDA-approved drugs were inactive, reflecting the optimized pharmacological properties of the latter. Our results suggest that low CYP 2C isozyme activity is a common property of drugs, whereas other isozymes, such as CYP 2D6, show little discrimination between drugs and unoptimized compounds found in screening libraries. We also identified chemical substructures that differentiated between the five isozymes. The pharmacological compendium described here should further the understanding of CYP isozymes.
Nature Biotechnology 11/2009; 27(11):1050-5. · 29.50 Impact Factor
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ABSTRACT: Methylation of lysine residues on the tails of histone proteins is a major determinant of the transcription state of associated DNA coding regions. The interplay among methylation states and other histone modifications to direct transcriptional outcome is referred to as the histone code. In addition to histone methyltransferases and demethylases which function to modify the methylation state of lysine sidechains, other proteins recognize specific histone methylation marks essentially serving as code readers. While these interactions are highly specific with respect to site and methylation state of particular lysine residues, they are generally weak and therefore difficult to monitor by traditional assay techniques. Herein, we present the design and implementation of a homogeneous, miniaturizable, and sensitive assay for histone methylation-dependent interactions. We use AlphaScreen, a chemiluminescence-based technique, to monitor the interactions of chromodomains (MPP8, HP1beta and CHD1), tudor domains (JMJD2A) and plant homeodomains (RAG2) with their cognate trimethyllysine histone partners. The utility of the method was demonstrated by profiling the binding specificities of chromo- and tudor domains toward several histone marks. The simplicity of design and the sensitive and robust nature of this assay should make it applicable to a range of epigenetic studies, including the search for novel inhibitors of methylation-dependent interactions.
Nucleic Acids Research 11/2009; 38(2):e11. · 8.03 Impact Factor
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Ronald L Johnson,
Ruili Huang,
Ajit Jadhav,
Noel Southall,
Jennifer Wichterman,
Ryan MacArthur,
Menghang Xia,
Kun Bi,
John Printen, Christopher P Austin,
James Inglese
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ABSTRACT: Small molecule modulators are critical for dissecting and understanding signaling pathways at the molecular level. Interleukin 6 (IL-6) is a cytokine that signals via the JAK-STAT pathway and is implicated in cancer and inflammation. To identify modulators of this pathway, we screened a chemical collection against an IL-6 responsive cell line stably expressing a beta-lactamase reporter gene fused to a sis-inducible element (SIE-bla cells). This assay was optimized for a 1536-well microplate format and screened against 11 693 small molecules using quantitative high-throughput screening (qHTS), a method that assays a chemical library at multiple concentrations to generate titration-response profiles for each compound. The qHTS recovered 564 actives with well-fit curves that clustered into 32 distinct chemical series of 13 activators and 19 inhibitors. A retrospective analysis of the qHTS data indicated that single concentration data at 1.5 and 7.7 microM scored 35 and 71% of qHTS actives, respectively, as inactive and were therefore false negatives. Following counter screens to identify fluorescent and non-selective series, we found four activator and one inhibitor series that modulated SIE-bla cells but did not show similar activity in reporter gene assays induced by EGF and hypoxia. Small molecules within these series will make useful tool compounds to investigate IL-6 signaling mediated by JAK-STAT activation.
Molecular BioSystems 10/2009; 5(9):1039-50. · 3.53 Impact Factor
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Jing Yuan,
Ronald L Johnson,
Ruili Huang,
Jennifer Wichterman,
Hongying Jiang,
Karen Hayton,
David A Fidock,
Thomas E Wellems,
James Inglese, Christopher P Austin,
Xin-zhuan Su
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ABSTRACT: Studies of gene function and molecular mechanisms in Plasmodium falciparum are hampered by difficulties in characterizing and measuring phenotypic differences between individual parasites. We screened seven parasite lines for differences in responses to 1,279 bioactive chemicals. Hundreds of compounds were active in inhibiting parasite growth; 607 differential chemical phenotypes, defined as pairwise IC(50) differences of fivefold or more between parasite lines, were cataloged. We mapped major determinants for three differential chemical phenotypes between the parents of a genetic cross, and we identified target genes by fine mapping and testing the responses of parasites in which candidate genes were genetically replaced with mutant alleles. Differential sensitivity to dihydroergotamine methanesulfonate (1), a serotonin receptor antagonist, was mapped to a gene encoding the homolog of human P-glycoprotein (PfPgh-1). This study identifies new leads for antimalarial drugs and demonstrates the utility of a high-throughput chemical genomic strategy for studying malaria traits.
Nature Chemical Biology 10/2009; 5(10):765-71. · 14.69 Impact Factor
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ABSTRACT: In support of the U.S. Tox21 program, we have developed a simple and chemically intuitive model we call weighted feature significance (WFS) to predict the toxicological activity of compounds, based on the statistical enrichment of structural features in toxic compounds. We trained and tested the model on the following: (1) data from quantitative high-throughput screening cytotoxicity and caspase activation assays conducted at the National Institutes of Health Chemical Genomics Center, (2) data from Salmonella typhimurium reverse mutagenicity assays conducted by the U.S. National Toxicology Program, and (3) hepatotoxicity data published in the Registry of Toxic Effects of Chemical Substances. Enrichments of structural features in toxic compounds are evaluated for their statistical significance and compiled into a simple additive model of toxicity and then used to score new compounds for potential toxicity. The predictive power of the model for cytotoxicity was validated using an independent set of compounds from the U.S. Environmental Protection Agency tested also at the National Institutes of Health Chemical Genomics Center. We compared the performance of our WFS approach with classical classification methods such as Naive Bayesian clustering and support vector machines. In most test cases, WFS showed similar or slightly better predictive power, especially in the prediction of hepatotoxic compounds, where WFS appeared to have the best performance among the three methods. The new algorithm has the important advantages of simplicity, power, interpretability, and ease of implementation.
Toxicological Sciences 10/2009; 112(2):385-93. · 4.65 Impact Factor
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Craig J Thomas,
Douglas S Auld,
Ruili Huang,
Wenwei Huang,
Ajit Jadhav,
Ronald L Johnson,
William Leister,
David J Maloney,
Juan J Marugan,
Sam Michael,
Anton Simeonov,
Noel Southall,
Menghang Xia,
Wei Zheng,
James Inglese, Christopher P Austin
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ABSTRACT: The NIH Chemical Genomics Center (NCGC) was the inaugural center of the Molecular Libraries and Screening Center Network (MLSCN). Along with the nine other research centers of the MLSCN, the NCGC was established with a primary goal of bringing industrial technology and experience to empower the scientific community with small molecule compounds for use in their research. We intend this review to serve as 1) an introduction to the NCGC standard operating procedures, 2) an overview of several of the lessons learned during the pilot phase and 3) a review of several of the innovative discoveries reported during the pilot phase of the MLSCN.
Current topics in medicinal chemistry 10/2009; 9(13):1181-93. · 4.47 Impact Factor
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Zhen Wang,
Min Zheng,
Zhichuan Li,
Ruiguo Li,
Lijun Jia,
Xiufang Xiong,
Noel Southall,
Shaomeng Wang,
Menghang Xia, Christopher P Austin,
Wei Zheng,
Zijian Xie,
Yi Sun
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ABSTRACT: p53 is regulated at multiple levels. We report here that p53, in multiple lines of human cancer cells, is down-regulated by cardiac glycoside drugs digoxin and ouabain, potent inhibitors of Na(+)/K(+)-ATPase. These drugs reduced the basal levels of p53 protein at nanomolar concentrations in a dose-, time-, and cancer cell line-dependent manner, but independent of p53 status of wild-type or mutant. The drugs also reduced the levels of p53 induced by its activators as well as p53 transfected into human cancer cells, regardless of its status. Interestingly, the drugs had no effect on endogenous p53 in two immortalized human cell lines. Mechanistically, p53 reduction occurred not at the mRNA levels but at the protein levels, as a result of reduced protein synthesis rather than enhanced degradation. The cellular sensitivity to drug-induced p53 reduction was not associated with the levels of alphasubunits of Na(+)/K(+)-ATPase in different cell lines. Although lowering extracellular K(+) did not reduce p53 as did ouabain and digoxin, it did potentiate both digoxin- and ouabain-induced p53 reduction in sensitive lines. Finally, p53 reduction seems to be triggered by activation of Src/mitogen-activated protein kinase (MAPK) signaling pathways upon drug binding to the Na(+)/K(+)-ATPase and can be completely blocked by the inhibitors of Src or MAP/ERK kinase. This is the first report that cardiac glycoside drugs, by initiating the Src/MAPK signaling pathways, reduce the p53 levels via inhibition of p53 protein synthesis. The drugs may be useful in the treatment of human cancers with a gain-of-function p53 mutation.
Cancer Research 09/2009; 69(16):6556-64. · 7.86 Impact Factor
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Ganesha Rai,
Ahmed A Sayed,
Wendy A Lea,
Hans F Luecke,
Harinath Chakrapani,
Stefanie Prast-Nielsen,
Ajit Jadhav,
William Leister,
Min Shen,
James Inglese, Christopher P Austin,
Larry Keefer,
Elias S J Arnér,
Anton Simeonov,
David J Maloney,
David L Williams,
Craig J Thomas
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ABSTRACT: Schistosomiasis is a chronic parasitic disease affecting hundreds of millions of individuals worldwide. Current treatment depends on a single agent, praziquantel, raising concerns of emergence of resistant parasites. Here, we continue our explorations of an oxadiazole-2-oxide class of compounds we recently identified as inhibitors of thioredoxin glutathione reductase (TGR), a selenocysteine-containing flavoenzyme required by the parasite to maintain proper cellular redox balance. Through systematic evaluation of the core molecular structure of this chemotype, we define the essential pharmacophore, establish a link between the nitric oxide donation and TGR inhibition, determine the selectivity for this chemotype versus related reductase enzymes, and present evidence that these agents can be modified to possess appropriate drug metabolism and pharmacokinetic properties. The mechanistic link between exogenous NO donation and parasite injury is expanded and better defined. The results of these studies verify the utility of oxadiazole-2-oxides as novel inhibitors of TGR and as efficacious antischistosomal agents.
Journal of Medicinal Chemistry 09/2009; 52(20):6474-83. · 4.80 Impact Factor
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ABSTRACT: All solid malignancies share characteristic traits, including unlimited cellular proliferation, evasion of immune regulation, and the propensity to metastasize. The authors have previously described that a subnuclear structure, the perinucleolar compartment (PNC), is associated with the metastatic phenotype in solid tumor cancer cells. The percentage of cancer cells that contain PNCs (PNC prevalence) is indicative of the malignancy of a tumor both in vitro and in vivo, and thus PNC prevalence is a marker that reflects metastatic capability in a population of tumor cells. Although the function of the PNC remains to be determined, the PNC is highly enriched with small RNAs and RNA binding proteins. The initial chemical biology studies using a set of anticancer drugs that disassemble PNCs revealed a direct association of the structure with DNA. Therefore, PNC prevalence reduction as a phenotypic marker can be used to identify compounds that target cellular processes required for PNC maintenance and hence used to elucidate the nature of the PNC function. Here the authors report the development of an automated high-content screening assay that is capable of detecting PNC prevalence in prostate cancer cells (PC-3M) stably expressing a green fluorescent protein (GFP)-fusion protein that localizes to the PNC. The assay was optimized using known PNC-reducing drugs and non-PNC-reducing cytotoxic drugs. After optimization, the fidelity of the assay was probed with a collection of 8284 compounds and was shown to be robust and capable of detecting known and novel PNC-reducing compounds, making it the first reported high-content phenotypic screen for small changes in nuclear structure.
Journal of Biomolecular Screening 09/2009; 14(9):1045-53. · 2.05 Impact Factor
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ABSTRACT: Specialized DNA polymerases are involved in DNA synthesis during base-excision repair and translesion synthesis across a wide range of chemically modified DNA templates. Notable features of these enzymes include low catalytic efficiency, low processivity and low fidelity. Traditionally, in vitro studies of these enzymes have utilized radiolabeled substrates and gel electrophoretic separation of products. We have developed a simple homogeneous fluorescence-based method to study the enzymology of specialized DNA polymerases in real time. The method is based on fluorescent reporter strand displacement from a tripartite substrate containing a quencher-labeled template strand, an unlabeled primer and a fluorophore-labeled reporter. With this method, we could follow the activity of human DNA polymerases beta, eta, iota and kappa under different reaction conditions, and we investigated incorporation of the aberrant nucleotide, 8-oxodGTP, as well as bypass of an abasic site or 8-oxoG DNA template lesion in different configurations. Lastly, we demonstrate that the method can be used for small molecule inhibitor discovery and characterization in highly miniaturized settings, and we report the first nanomolar inhibitors of Y-family DNA polymerases iota and eta. The fluorogenic method presented here should facilitate mechanistic and inhibitor investigations of these polymerases and is also applicable to the study of highly processive replicative polymerases.
Nucleic Acids Research 09/2009; 37(19):e128. · 8.03 Impact Factor
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Alex Crowe,
Wenwei Huang,
Carlo Ballatore,
Ronald L Johnson,
Anne-Marie L Hogan,
Ruili Huang,
Jennifer Wichterman,
Joshua McCoy,
Donna Huryn,
Douglas S Auld,
Amos B Smith,
James Inglese,
John Q Trojanowski, Christopher P Austin,
Kurt R Brunden,
Virginia M-Y Lee
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ABSTRACT: Inclusions comprised of fibrils of the microtubule- (MT-) associated protein tau are found in the brains of those with Alzheimer's disease (AD) and other neurodegenerative tauopathies. The pathology that is observed in these diseases is believed to result from the formation of toxic tau oligomers or fibrils and/or from the loss of normal tau function due to its sequestration into insoluble deposits. Hence, small molecules that prevent tau oligomerization and/or fibrillization might have therapeutic value. Indeed, examples of such compounds have been published, but nearly all have properties that render them unsuitable as drug candidates. For these reasons, we conducted quantitative high-throughput screening (qHTS) of approximately 292000 compounds to identify drug-like inhibitors of tau assembly. The fibrillization of a truncated tau fragment that contains four MT-binding domains was monitored in an assay that employed complementary thioflavin T fluorescence and fluorescence polarization methods. Previously described classes of inhibitors as well as new scaffolds were identified, including novel aminothienopyridazines (ATPZs). A number of ATPZ analogues were synthesized, and structure-activity relationships were defined. Further characterization of representative ATPZ compounds showed they do not interfere with tau-mediated MT assembly, and they are significantly more effective at preventing the fibrillization of tau than the Abeta(1-42) peptide which forms AD senile plaques. Thus, the ATPZ molecules described here represent a novel class of tau assembly inhibitors that merit further development for testing in animal models of AD-like tau pathology.
Biochemistry 08/2009; 48(32):7732-45. · 3.42 Impact Factor
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Amanda P Skoumbourdis,
Christopher A Leclair,
Eduard Stefan,
Adrian G Turjanski,
William Maguire,
Steven A Titus,
Ruili Huang,
Douglas S Auld,
James Inglese, Christopher P Austin,
Stephen W Michnick,
Menghang Xia,
Craig J Thomas
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ABSTRACT: An expansion of structure-activity studies on a series of substituted 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine PDE4 inhibitors and the introduction of a related [1,2,4]triazolo[4,3-b]pyridazine based inhibitor of PDE4 is presented. The development of SAR included strategic incorporation of known substituents on the critical catachol diether moiety of the 6-phenyl appendage on each heterocyclic core. From these studies, (R)-3-(2,5-dimethoxyphenyl)-6-(4-methoxy-3-(tetrahydrofuran-3-yloxy)phenyl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine (10) and (R)-3-(2,5-dimethoxyphenyl)-6-(4-methoxy-3-(tetrahydrofuran-3-yloxy)phenyl)-[1,2,4]triazolo[4,3-b]pyridazine (18) were identified as highly potent PDE4A inhibitors. Each of these analogues was submitted across a panel of 21 PDE family members and was shown to be highly selective for PDE4 isoforms (PDE4A, PDE4B, PDE4C, PDE4D). Both 10 and 18 were then evaluated in divergent cell-based assays to assess their relevant use as probes of PDE4 activity. Finally, docking studies with selective ligands (including 10 and 18) were undertaken to better understand this chemotypes ability to bind and inhibit PDE4 selectively.
Bioorganic & medicinal chemistry letters 08/2009; 19(13):3686-92. · 2.65 Impact Factor
