Sample records for active small molecules

  1. Antimalarial Activity of Small-Molecule Benzothiazole Hydrazones (United States)

    Sarkar, Souvik; Siddiqui, Asim A.; Saha, Shubhra J.; De, Rudranil; Mazumder, Somnath; Banerjee, Chinmoy; Iqbal, Mohd S.; Nag, Shiladitya; Adhikari, Susanta


    We synthesized a new series of conjugated hydrazones that were found to be active against malaria parasite in vitro, as well as in vivo in a murine model. These hydrazones concentration-dependently chelated free iron and offered antimalarial activity. Upon screening of the synthesized hydrazones, compound 5f was found to be the most active iron chelator, as well as antiplasmodial. Compound 5f also interacted with free heme (KD [equilibrium dissociation constant] = 1.17 ± 0.8 μM), an iron-containing tetrapyrrole released after hemoglobin digestion by the parasite, and inhibited heme polymerization by parasite lysate. Structure-activity relationship studies indicated that a nitrogen- and sulfur-substituted five-membered aromatic ring present within the benzothiazole hydrazones might be responsible for their antimalarial activity. The dose-dependent antimalarial and heme polymerization inhibitory activities of the lead compound 5f were further validated by following [3H]hypoxanthine incorporation and hemozoin formation in parasite, respectively. It is worth mentioning that compound 5f exhibited antiplasmodial activity in vitro against a chloroquine/pyrimethamine-resistant strain of Plasmodium falciparum (K1). We also evaluated in vivo antimalarial activity of compound 5f in a murine model where a lethal multiple-drug-resistant strain of Plasmodium yoelii was used to infect Swiss albino mice. Compound 5f significantly suppressed the growth of parasite, and the infected mice experienced longer life spans upon treatment with this compound. During in vitro and in vivo toxicity assays, compound 5f showed minimal alteration in biochemical and hematological parameters compared to control. In conclusion, we identified a new class of hydrazone with therapeutic potential against malaria. PMID:27139466

  2. Approach for targeting Ras with small molecules that activate SOS-mediated nucleotide exchange. (United States)

    Burns, Michael C; Sun, Qi; Daniels, R Nathan; Camper, DeMarco; Kennedy, J Phillip; Phan, Jason; Olejniczak, Edward T; Lee, Taekyu; Waterson, Alex G; Rossanese, Olivia W; Fesik, Stephen W


    Aberrant activation of the small GTPase Ras by oncogenic mutation or constitutively active upstream receptor tyrosine kinases results in the deregulation of cellular signals governing growth and survival in ∼30% of all human cancers. However, the discovery of potent inhibitors of Ras has been difficult to achieve. Here, we report the identification of small molecules that bind to a unique pocket on the Ras:Son of Sevenless (SOS):Ras complex, increase the rate of SOS-catalyzed nucleotide exchange in vitro, and modulate Ras signaling pathways in cells. X-ray crystallography of Ras:SOS:Ras in complex with these molecules reveals that the compounds bind in a hydrophobic pocket in the CDC25 domain of SOS adjacent to the Switch II region of Ras. The structure-activity relationships exhibited by these compounds can be rationalized on the basis of multiple X-ray cocrystal structures. Mutational analyses confirmed the functional relevance of this binding site and showed it to be essential for compound activity. These molecules increase Ras-GTP levels and disrupt MAPK and PI3K signaling in cells at low micromolar concentrations. These small molecules represent tools to study the acute activation of Ras and highlight a pocket on SOS that may be exploited to modulate Ras signaling.

  3. In Vitro Selection for Small-Molecule-Triggered Strand Displacement and Riboswitch Activity. (United States)

    Martini, Laura; Meyer, Adam J; Ellefson, Jared W; Milligan, John N; Forlin, Michele; Ellington, Andrew D; Mansy, Sheref S


    An in vitro selection method for ligand-responsive RNA sensors was developed that exploited strand displacement reactions. The RNA library was based on the thiamine pyrophosphate (TPP) riboswitch, and RNA sequences capable of hybridizing to a target duplex DNA in a TPP regulated manner were identified. After three rounds of selection, RNA molecules that mediated a strand exchange reaction upon TPP binding were enriched. The enriched sequences also showed riboswitch activity. Our results demonstrated that small-molecule-responsive nucleic acid sensors can be selected to control the activity of target nucleic acid circuitry.

  4. Small molecule inhibitors block Gas6-inducible TAM activation and tumorigenicity (United States)

    Kimani, Stanley G.; Kumar, Sushil; Bansal, Nitu; Singh, Kamalendra; Kholodovych, Vladyslav; Comollo, Thomas; Peng, Youyi; Kotenko, Sergei V.; Sarafianos, Stefan G.; Bertino, Joseph R.; Welsh, William J.; Birge, Raymond B.


    TAM receptors (Tyro-3, Axl, and Mertk) are a family of three homologous type I receptor tyrosine kinases that are implicated in several human malignancies. Overexpression of TAMs and their major ligand Growth arrest-specific factor 6 (Gas6) is associated with more aggressive staging of cancers, poorer predicted patient survival, acquired drug resistance and metastasis. Here we describe small molecule inhibitors (RU-301 and RU-302) that target the extracellular domain of Axl at the interface of the Ig-1 ectodomain of Axl and the Lg-1 of Gas6. These inhibitors effectively block Gas6-inducible Axl receptor activation with low micromolar IC50s in cell-based reporter assays, inhibit Gas6-inducible motility in Axl-expressing cell lines, and suppress H1299 lung cancer tumor growth in a mouse xenograft NOD-SCIDγ model. Furthermore, using homology models and biochemical verifications, we show that RU301 and 302 also inhibit Gas6 inducible activation of Mertk and Tyro3 suggesting they can act as pan-TAM inhibitors that block the interface between the TAM Ig1 ectodomain and the Gas6 Lg domain. Together, these observations establish that small molecules that bind to the interface between TAM Ig1 domain and Gas6 Lg1 domain can inhibit TAM activation, and support the further development of small molecule Gas6-TAM interaction inhibitors as a novel class of cancer therapeutics. PMID:28272423

  5. Structure based discovery of small molecules to regulate the activity of human insulin degrading enzyme.

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    Bilal Çakir

    Full Text Available BACKGROUND: Insulin-degrading enzyme (IDE is an allosteric Zn(+2 metalloprotease involved in the degradation of many peptides including amyloid-β, and insulin that play key roles in Alzheimer's disease (AD and type 2 diabetes mellitus (T2DM, respectively. Therefore, the use of therapeutic agents that regulate the activity of IDE would be a viable approach towards generating pharmaceutical treatments for these diseases. Crystal structure of IDE revealed that N-terminal has an exosite which is ∼30 Å away from the catalytic region and serves as a regulation site by orientation of the substrates of IDE to the catalytic site. It is possible to find small molecules that bind to the exosite of IDE and enhance its proteolytic activity towards different substrates. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we applied structure based drug design method combined with experimental methods to discover four novel molecules that enhance the activity of human IDE. The novel compounds, designated as D3, D4, D6, and D10 enhanced IDE mediated proteolysis of substrate V, insulin and amyloid-β, while enhanced degradation profiles were obtained towards substrate V and insulin in the presence of D10 only. CONCLUSION/SIGNIFICANCE: This paper describes the first examples of a computer-aided discovery of IDE regulators, showing that in vitro and in vivo activation of this important enzyme with small molecules is possible.

  6. Small molecules activating TrkB receptor for treating a variety of CNS disorders. (United States)

    Zeng, Yan; Wang, Xiaonan; Wang, Qiang; Liu, Shumin; Hu, Xiamin; McClintock, Shawn M


    The brain-derived neurotrophic factor (BDNF) and its high affinity receptor tropomyosin-receptor-kinase B (TrkB) play a critical role in neuronal differentiation and survival, synapse plasticity, and memory. Indeed, both have been implicated in the pathophysiology of numerous diseases. Although the remarkable therapeutic potential of BDNF has generated much research over the past decade, the poor pharmacokinetics and adverse side effect profile have limited its clinical usefulness of BDNF. Small compounds that mimic BDNF's neurotrophic signaling and overcome the pharmacokinetic and side effect barriers may have greater therapeutic potential. The purpose of this review is to provide a survey of the various strategies taken towards the development of small molecule mimetics for BDNF and the selective TrkB agonist. A particular focus was placed on TrkB agonist 7, 8-dihydroxyflavone, which modulates multiple functions and has demonstrated remarkable therapeutic efficacy in a variety of central nervous system disease models. Two other small molecules included in this review are adenosine A2A receptor agonists that indirectly activate TrkB, and TrkB binding domains of BDNF, loop II-LM22A compounds that directly activate TrkB. These alternative molecules have shown promise in preclinical studies and may be included in prospective clinical investigations.

  7. Early-Late Heterobimetallic Complexes Linked by Phosphinoamide Ligands. Tuning Redox Potentials and Small Molecule Activation

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    Thomas, Christine M. [Brandeis Univ., Waltham, MA (United States)


    Recent attention in the chemical community has been focused on the energy efficient and environmentally benign conversion of abundant small molecules (CO2, H2O, etc.) to useful liquid fuels. This project addresses these goals by examining fundamental aspects of catalyst design to ultimately access small molecule activation processes under mild conditions. Specifically, Thomas and coworkers have targetted heterobimetallic complexes that feature metal centers with vastly different electronic properties, dictated both by their respective positions on the periodic table and their coordination environment. Unlike homobimetallic complexes featuring identical or similar metals, the bonds between metals in early/late heterobimetallics are more polarized, with the more electron-rich late metal center donating electron density to the more electron-deficient early metal center. While metal-metal bonds pose an interesting strategy for storing redox equivalents and stabilizing reactive metal fragments, the polar character of metal-metal bonds in heterobimetallic complexes renders these molecules ideally poised to react with small molecule substrates via cleavage of energy-rich single and double bonds. In addition, metal-metal interactions have been shown to dramatically affect redox potentials and promote multielectron redox activity, suggesting that metal-metal interactions may provide a mechanism to tune redox potentials and access substrate reduction/activation at mild overpotentials. This research project has provided a better fundamental understanding of how interactions between transition metals can be used as a strategy to promote and/or control chemical transformations related to the clean production of fuels. While this project focused on the study of homogeneous systems, it is anticipated that the broad conclusions drawn from these investigations will be applicable to heterogeneous catalysis as well, particularly on heterogeneous processes that occur at interfaces in

  8. Small-molecule activation of SERCA2a SUMOylation for the treatment of heart failure (United States)

    Kho, Changwon; Lee, Ahyoung; Jeong, Dongtak; Oh, Jae Gyun; Gorski, Przemek A.; Fish, Kenneth; Sanchez, Roberto; DeVita, Robert J.; Christensen, Geir; Dahl, Russell; Hajjar, Roger J.


    Decreased activity and expression of the cardiac sarcoplasmic reticulum calcium ATPase (SERCA2a), a critical pump regulating calcium cycling in cardiomyocyte, are hallmarks of heart failure. We have previously described a role for the small ubiquitin-like modifier type 1 (SUMO-1) as a regulator of SERCA2a and have shown that gene transfer of SUMO-1 in rodents and large animal models of heart failure restores cardiac function. Here, we identify and characterize a small molecule, N106, which increases SUMOylation of SERCA2a. This compound directly activates the SUMO-activating enzyme, E1 ligase, and triggers intrinsic SUMOylation of SERCA2a. We identify a pocket on SUMO E1 likely to be responsible for N106's effect. N106 treatment increases contractile properties of cultured rat cardiomyocytes and significantly improves ventricular function in mice with heart failure. This first-in-class small-molecule activator targeting SERCA2a SUMOylation may serve as a potential therapeutic strategy for treatment of heart failure. PMID:26068603

  9. Conserved Active Site Residues Limit Inhibition of a Copper-Containing Nitrite By Small Molecules

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    Tocheva, E.I.; Eltis, L.D.; Murphy, M.E.P.


    The interaction of copper-containing dissimilatory nitrite reductase from Alcaligenes faecalis S-6 ( AfNiR) with each of five small molecules was studied using crystallography and steady-state kinetics. Structural studies revealed that each small molecule interacted with the oxidized catalytic type 2 copper of AfNiR. Three small molecules (formate, acetate and nitrate) mimic the substrate by having at least two oxygen atoms for bidentate coordination to the type 2 copper atom. These three anions bound to the copper ion in the same asymmetric, bidentate manner as nitrite. Consistent with their weak inhibition of the enzyme ( K i >50 mM), the Cu-O distances in these AfNiR-inhibitor complexes were approximately 0.15 A longer than that observed in the AfNiR-nitrite complex. The binding mode of each inhibitor is determined in part by steric interactions with the side chain of active site residue Ile257. Moreover, the side chain of Asp98, a conserved residue that hydrogen bonds to type 2 copper-bound nitrite and nitric oxide, was either disordered or pointed away from the inhibitors. Acetate and formate inhibited AfNiR in a mixed fashion, consistent with the occurrence of second acetate binding site in the AfNiR-acetate complex that occludes access to the type 2 copper. A fourth small molecule, nitrous oxide, bound to the oxidized metal in a side-on fashion reminiscent of nitric oxide to the reduced copper. Nevertheless, nitrous oxide bound at a farther distance from the metal. The fifth small molecule, azide, inhibited the reduction of nitrite by AfNiR most strongly ( K ic = 2.0 +/- 0.1 mM). This ligand bound to the type 2 copper center end-on with a Cu-N c distance of approximately 2 A, and was the only inhibitor to form a hydrogen bond with Asp98. Overall, the data substantiate the roles of Asp98 and Ile257 in discriminating substrate from other small anions.

  10. Structure Based Discovery of Small Molecules to Regulate the Activity of Human Insulin Degrading Enzyme


    Bilal Çakir; Onur Dağliyan; Ezgi Dağyildiz; İbrahim Bariş; Ibrahim Halil Kavakli; Seda Kizilel; Metin Türkay


    Structure Based Discovery of Small Molecules to Regulate the Activity of Human Insulin Degrading Enzyme Bilal C¸ akir1, Onur Dag˘ liyan1, Ezgi Dag˘ yildiz1, I˙brahim Baris¸1, Ibrahim Halil Kavakli1,2*, Seda Kizilel1*, Metin Tu¨ rkay3* 1 Department of Chemical and Biological Engineering, Koc¸ University, Sariyer, Istanbul, Turkey, 2 Department of Molecular Biology and Genetics, Koc¸ University, Sariyer, Istanbul, Turkey, 3 Department of Industrial Engineering, Koc¸ University...

  11. Identification of a small molecule activator of novel PKCs for promoting glucose-dependent insulin secretion

    Institute of Scientific and Technical Information of China (English)

    Shuai Han; Heling Pan; Jianhua Zhang; Li Tan; Dawei Ma; Junying Yuan; Jia-Rui Wu


    Using an image-based screen for small molecules that can affect Golgi morphology, we identify a small molecule,Sioc145, which can enlarge the Golgi compartments and promote protein secretion. More importantly, Siocl45 potentiates insulin secretion in a glucose-dependent manner. We show that Sioc145 selectively activates novel protein kinase Cs (nPKCs; δ and ε) but not conventional PKCs;cPKCs; a, βI and βll) in INS-1E insulinoma cells. In contrast, PMA, a non-selective activator of cPKCs and nPKCs, promotes insulin secretion independent of glucose concentrations. Furthermore, we demonstrate that Sioc145 and PMA show differential abilities in depolarizing the cell membrane, and suggest that Sioc145 promotes insulin secretion in the amplifying pathway downstream of K ATp channels. In pancreatic islets, the treatment with Sioc145 enhances the second phase of insulin secretion. Increased insulin granules close to the plasma membrane are observed after Sioc145 treatment. Finally, the administration of Sioc145 to diabetic GK rats increases their serum insulin levels and improves glucose tolerance. Collectively, our studies identify Sioc145 as a novel glucose-dependent insulinotropic compound via selectively activating nPKCs.

  12. In vitro and in vivo activity of a novel antifungal small molecule against Candida infections.

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    Sarah Sze Wah Wong

    Full Text Available Candida is the most common fungal pathogen of humans worldwide and has become a major clinical problem because of the growing number of immunocompromised patients, who are susceptible to infection. Moreover, the number of available antifungals is limited, and antifungal-resistant Candida strains are emerging. New and effective antifungals are therefore urgently needed. Here, we discovered a small molecule with activity against Candida spp. both in vitro and in vivo. We screened a library of 50,240 small molecules for inhibitors of yeast-to-hypha transition, a major virulence attribute of Candida albicans. This screening identified 20 active compounds. Further examination of the in vitro antifungal and anti-biofilm properties of these compounds, using a range of Candida spp., led to the discovery of SM21, a highly potent antifungal molecule (minimum inhibitory concentration (MIC 0.2-1.6 µg/ml. In vitro, SM21 was toxic to fungi but not to various human cell lines or bacterial species and was active against Candida isolates that are resistant to existing antifungal agents. Moreover, SM21 was relatively more effective against biofilms of Candida spp. than the current antifungal agents. In vivo, SM21 prevented the death of mice in a systemic candidiasis model and was also more effective than the common antifungal nystatin at reducing the extent of tongue lesions in a mouse model of oral candidiasis. Propidium iodide uptake assay showed that SM21 affected the integrity of the cell membrane. Taken together, our results indicate that SM21 has the potential to be developed as a novel antifungal agent for clinical use.

  13. Small molecule activators of SIRT1 replicate signaling pathways triggered by calorie restriction in vivo

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    Lavu Siva


    Full Text Available Abstract Background Calorie restriction (CR produces a number of health benefits and ameliorates diseases of aging such as type 2 diabetes. The components of the pathways downstream of CR may provide intervention points for developing therapeutics for treating diseases of aging. The NAD+-dependent protein deacetylase SIRT1 has been implicated as one of the key downstream regulators of CR in yeast, rodents, and humans. Small molecule activators of SIRT1 have been identified that exhibit efficacy in animal models of diseases typically associated with aging including type 2 diabetes. To identify molecular processes induced in the liver of mice treated with two structurally distinct SIRT1 activators, SIRT501 (formulated resveratrol and SRT1720, for three days, we utilized a systems biology approach and applied Causal Network Modeling (CNM on gene expression data to elucidate downstream effects of SIRT1 activation. Results Here we demonstrate that SIRT1 activators recapitulate many of the molecular events downstream of CR in vivo, such as enhancing mitochondrial biogenesis, improving metabolic signaling pathways, and blunting pro-inflammatory pathways in mice fed a high fat, high calorie diet. Conclusion CNM of gene expression data from mice treated with SRT501 or SRT1720 in combination with supporting in vitro and in vivo data demonstrates that SRT501 and SRT1720 produce a signaling profile that mirrors CR, improves glucose and insulin homeostasis, and acts via SIRT1 activation in vivo. Taken together these results are encouraging regarding the use of small molecule activators of SIRT1 for therapeutic intervention into type 2 diabetes, a strategy which is currently being investigated in multiple clinical trials.

  14. Small-molecule CFTR activators increase tear secretion and prevent experimental dry eye disease. (United States)

    Flores, Alyssa M; Casey, Scott D; Felix, Christian M; Phuan, Puay W; Verkman, A S; Levin, Marc H


    Dry eye disorders, including Sjögren's syndrome, constitute a common problem in the aging population, with limited effective therapeutic options available. The cAMP-activated Cl(-) channel cystic fibrosis transmembrane conductance regulator (CFTR) is a major prosecretory channel at the ocular surface. We investigated whether compounds that target CFTR can correct the abnormal tear film in dry eye. Small-molecule activators of human wild-type CFTR identified by high-throughput screening were evaluated in cell culture and in vivo assays, to select compounds that stimulate Cl(-)-driven fluid secretion across the ocular surface in mice. An aminophenyl-1,3,5-triazine, CFTRact-K089, fully activated CFTR in cell cultures with EC50 ∼250 nM and produced an ∼8.5 mV hyperpolarization in ocular surface potential difference. When delivered topically, CFTRact-K089 doubled basal tear volume for 4 h and had no effect in CF mice. CFTRact-K089 showed sustained tear film bioavailability without detectable systemic absorption. In a mouse model of aqueous-deficient dry eye produced by lacrimal ablation, topical administration of 0.1 nmol CFTRact-K089 3 times daily restored tear volume to basal levels, preventing corneal epithelial disruption when initiated at the time of surgery and reversing it when started after development of dry eye. Our results support the potential utility of CFTR-targeted activators as a novel prosecretory treatment for dry eye.-Flores, A. M., Casey, S. D., Felix, C. M., Phuan, P. W., Verkman, A. S., Levin, M. H. Small-molecule CFTR activators increase tear secretion and prevent experimental dry eye disease.

  15. Small Molecule-Induced Allosteric Activation of the Vibrio Cholerae RTX Cysteine Protease Domain

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    Lupardus, P.J.; Shen, A.; Bogyo, M.; Garcia, K.C.


    Vibrio cholerae RTX (repeats in toxin) is an actin-disrupting toxin that is autoprocessed by an internal cysteine protease domain (CPD). The RTX CPD is efficiently activated by the eukaryote-specific small molecule inositol hexakisphosphate (InsP{sub 6}), and we present the 2.1 angstrom structure of the RTX CPD in complex with InsP{sub 6}. InsP{sub 6} binds to a conserved basic cleft that is distant from the protease active site. Biochemical and kinetic analyses of CPD mutants indicate that InsP{sub 6} binding induces an allosteric switch that leads to the autoprocessing and intracellular release of toxin-effector domains.

  16. Small-molecule activators of insulin-degrading enzyme discovered through high-throughput compound screening.

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    Christelle Cabrol

    Full Text Available BACKGROUND: Hypocatabolism of the amyloid beta-protein (Abeta by insulin-degrading enzyme (IDE is implicated in the pathogenesis of Alzheimer disease (AD, making pharmacological activation of IDE an attractive therapeutic strategy. However, it has not been established whether the proteolytic activity of IDE can be enhanced by drug-like compounds. METHODOLOGY/PRINCIPAL FINDINGS: Based on the finding that ATP and other nucleotide polyphosphates modulate IDE activity at physiological concentrations, we conducted parallel high-throughput screening campaigns in the absence or presence of ATP and identified two compounds--designated Ia1 and Ia2--that significantly stimulate IDE proteolytic activity. Both compounds were found to interfere with the crosslinking of a photoaffinity ATP analogue to IDE, suggesting that they interact with a bona fide ATP-binding domain within IDE. Unexpectedly, we observed highly synergistic activation effects when the activity of Ia1 or Ia2 was tested in the presence of ATP, a finding that has implications for the mechanisms underlying ATP-mediated activation of IDE. Notably, Ia1 and Ia2 activated the degradation of Abeta by approximately 700% and approximately 400%, respectively, albeit only when Abeta was presented in a mixture also containing shorter substrates. CONCLUSIONS/SIGNIFICANCE: This study describes the first examples of synthetic small-molecule activators of IDE, showing that pharmacological activation of this important protease with drug-like compounds is achievable. These novel activators help to establish the putative ATP-binding domain as a key modulator of IDE proteolytic activity and offer new insights into the modulatory action of ATP. Several larger lessons abstracted from this screen will help inform the design of future screening campaigns and facilitate the eventual development of IDE activators with therapeutic utility.

  17. Peptidomimetic Small Molecules Disrupt Type IV Secretion System Activity in Diverse Bacterial Pathogens

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    Carrie L. Shaffer


    Full Text Available Bacteria utilize complex type IV secretion systems (T4SSs to translocate diverse effector proteins or DNA into target cells. Despite the importance of T4SSs in bacterial pathogenesis, the mechanism by which these translocation machineries deliver cargo across the bacterial envelope remains poorly understood, and very few studies have investigated the use of synthetic molecules to disrupt T4SS-mediated transport. Here, we describe two synthetic small molecules (C10 and KSK85 that disrupt T4SS-dependent processes in multiple bacterial pathogens. Helicobacter pylori exploits a pilus appendage associated with the cag T4SS to inject an oncogenic effector protein (CagA and peptidoglycan into gastric epithelial cells. In H. pylori, KSK85 impedes biogenesis of the pilus appendage associated with the cag T4SS, while C10 disrupts cag T4SS activity without perturbing pilus assembly. In addition to the effects in H. pylori, we demonstrate that these compounds disrupt interbacterial DNA transfer by conjugative T4SSs in Escherichia coli and impede vir T4SS-mediated DNA delivery by Agrobacterium tumefaciens in a plant model of infection. Of note, C10 effectively disarmed dissemination of a derepressed IncF plasmid into a recipient bacterial population, thus demonstrating the potential of these compounds in mitigating the spread of antibiotic resistance determinants driven by conjugation. To our knowledge, this study is the first report of synthetic small molecules that impair delivery of both effector protein and DNA cargos by diverse T4SSs.

  18. Screening of pharmacologically active small molecule compounds identifies antifungal agents against Candida biofilms

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    Takao eWatamoto


    Full Text Available Candida species have emerged as important and common opportunistic human pathogens, particularly in immunocompromised individuals. The current antifungal therapies either have toxic side effects or are insufficiently effect. The aim of this study is develop new small-molecule antifungal compounds by library screening methods using C. albicans, and to evaluate their antifungal effects on Candida biofilms and cytotoxic effects on human cells. Wild-type C. albicans strain SC5314 was used in library screening. To identify antifungal compounds, we screened a small-molecule library of 1,280 pharmacologically active compounds (LOPAC1280TM using an antifungal susceptibility test (AST. To investigate the antifungal effects of the hit compounds, ASTs were conducted using Candida strains in various growth modes, including biofilms. We tested the cytotoxicity of the hit compounds using human gingival fibroblast (hGF cells to evaluate their clinical safety. Only 35 compounds were identified by screening, which inhibited the metabolic activity of C. albicans by >50%. Of these, 26 compounds had fungistatic effects and 9 compounds had fungicidal effects on C. albicans. Five compounds, BAY11-7082, BAY11-7085, sanguinarine chloride hydrate, ellipticine and CV-3988, had strong fungicidal effects and could inhibit the metabolic activity of Candida biofilms. However, BAY11-7082, BAY11-7085, sanguinarine chloride hydrate and ellipticine were cytotoxic to hGF cells at low concentrations. CV-3988 showed no cytotoxicity at a fungicidal concentration.Four of the compounds identified, BAY11-7082, BAY11-7085, sanguinarine chloride hydrate and ellipticine, had toxic effects on Candida strains and hGF cells. In contrast, CV-3988 had fungicidal effects on Candida strains, but low cytotoxic effects on hGF cells. Therefore, this screening reveals agent, CV-3988 that was previously unknown to be antifungal agent, which could be a novel therapies for superficial mucosal

  19. p53 Small Molecule Inhibitor Enhances Temozolomide Cytotoxic Activity against Intracranial Glioblastoma Xenografts (United States)

    Dinca, Eduard B.; Lu, Kan V.; Sarkaria, Jann N.; Pieper, Russell O.; Prados, Michael D.; Haas-Kogan, Daphne A.; VandenBerg, Scott R.; Berger, Mitchel S.; James, C. David


    In this study we investigated corresponding precursor and active forms of a p53 small molecule inhibitor for effect on temozolomide (TMZ) anti-tumor activity against glioblastoma (GBM), using both in vitro and in vivo experimental approaches. Results from in vitro cell viability analysis showed that the cytotoxic activity of TMZ was substantially increased when GBMs with wild-type p53 were co-treated with the active form of p53 inhibitor, and this heightened cytotoxic response was accompanied by increased PARP cleavage as well as elevated cellular phospho-H2AX. Analysis of the same series of GBMs, as intracranial xenografts in athymic mice, and administering corresponding p53 inhibitor precursor, that is converted to the active compound in vivo, yielded results consistent with the in vitro analyses: i.e., TMZ + p53 inhibitor precursor co-treatment, of three distinct wild-type p53 GBM xenografts, resulted in significant enhancement of TMZ anti-tumor effect relative to treatment with TMZ alone, as indicated by serial bioluminescence monitoring as well as survival analysis (p < 0.001 for co-treatment survival benefit in each case). Mice receiving intracranial injection with p53 null GBM showed similar survival benefit from TMZ treatment regardless of the presence or absence of p53 inhibitor precursor. In total, our results indicate that the p53 active and precursor inhibitor pair enhance TMZ cytotoxicity in vitro and in vivo, respectively, and do so in a p53-dependent manner. PMID:19074867

  20. Discovery of novel small molecule activators of β-catenin signaling.

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    Folkert Verkaar

    Full Text Available Wnt/β-catenin signaling plays a major role in embryonic development and adult stem cell maintenance. Reduced activation of the Wnt/β-catenin pathway underlies neurodegenerative disorders and aberrations in bone formation. Screening of a small molecule compound library with a β-galactosidase fragment complementation assay measuring β-catenin nuclear entry revealed bona fide activators of β-catenin signaling. The compounds stabilized cytoplasmic β-catenin and activated β-catenin-dependent reporter gene activity. Although the mechanism through which the compounds activate β-catenin signaling has yet to be determined, several key regulators of Wnt/β-catenin signaling, including glycogen synthase kinase 3 and Frizzled receptors, were excluded as the molecular target. The compounds displayed remarkable selectivity, as they only induced β-catenin signaling in a human osteosarcoma U2OS cell line and not in a variety of other cell lines examined. Our data indicate that differences in cellular Wnt/β-catenin signaling machinery can be exploited to identify cell type-specific activators of Wnt/β-catenin signaling.

  1. Tetrandrine identified in a small molecule screen to activate mesenchymal stem cells for enhanced immunomodulation. (United States)

    Yang, Zijiang; Concannon, John; Ng, Kelvin S; Seyb, Kathleen; Mortensen, Luke J; Ranganath, Sudhir; Gu, Fangqi; Levy, Oren; Tong, Zhixiang; Martyn, Keir; Zhao, Weian; Lin, Charles P; Glicksman, Marcie A; Karp, Jeffrey M


    Pre-treatment or priming of mesenchymal stem cells (MSC) prior to transplantation can significantly augment the immunosuppressive effect of MSC-based therapies. In this study, we screened a library of 1402 FDA-approved bioactive compounds to prime MSC. We identified tetrandrine as a potential hit that activates the secretion of prostaglandin E2 (PGE2), a potent immunosuppressive agent, by MSC. Tetrandrine increased MSC PGE2 secretion through the NF-κB/COX-2 signaling pathway. When co-cultured with mouse macrophages (RAW264.7), tetrandrine-primed MSC attenuated the level of TNF-α secreted by RAW264.7. Furthermore, systemic transplantation of primed MSC into a mouse ear skin inflammation model significantly reduced the level of TNF-α in the inflamed ear, compared to unprimed cells. Screening of small molecules to pre-condition cells prior to transplantation represents a promising strategy to boost the therapeutic potential of cell therapy.

  2. Osteogenic Activity of Locally Applied Small Molecule Drugs in a Rat Femur Defect Model

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    Jessica A. Cottrell


    Full Text Available The long-term success of arthroplastic joints is dependent on the stabilization of the implant within the skeletal site. Movement of the arthroplastic implant within the bone can stimulate osteolysis, and therefore methods which promote rigid fixation or bone growth are expected to enhance implant stability and the long-term success of joint arthroplasty. In the present study, we used a simple bilateral bone defect model to analyze the osteogenic activity of three small-molecule drug implants via microcomputerized tomography (micro-CT and histomorphometry. In this study, we show that local delivery of alendronate, but not lovastatin or omeprazole, led to significant new bone formation at the defect site. Since alendronate impedes osteoclast-development, it is theorized that alendronate treatment results in a net increase in bone formation by preventing osteoclast mediated remodeling of the newly formed bone and upregulating osteoblasts.

  3. Microencapsulation effectiveness of small active molecules in biopolymer by ultrasonic atomization technique. (United States)

    Cascone, Sara; Lamberti, Gaetano; Titomanlio, Giuseppe; Barba, Anna Angela; d'Amore, Matteo


    A method to produce biopolymeric (alginate) microparticles by ultrasonic assisted atomization, previously developed, has been applied to the production of microparticles loaded with a small active molecule (theophylline). Fine loaded alginate droplets have been cross-linked with divalent ions to produce microparticles. Once produced, the particles have been separated by centrifugation or filtration and then they have been dried. Drug release has been evaluated by dissolution tests, dissolving the dried particles in acidic solution at pH 1 for a given time and then at pH 7 to simulate the stomach and intestinal environment, respectively. The encapsulation efficiency and the drug loading have been investigated and the operating conditions have been changed to clarify the role of the transport phenomena on the overall process. To increase the drug loading, shorter separation time and better network's structure were identified as the key operating parameters to allow the process to gain interest from a practical point of view.

  4. Novel small-molecule AMPK activator orally exerts beneficial effects on diabetic db/db mice

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yuan-Yuan; Yu, Li-Fang; Zhang, Li-Na; Qiu, Bei-Ying; Su, Ming-Bo; Wu, Fang; Chen, Da-Kai; Pang, Tao; Gu, Min; Zhang, Wei; Ma, Wei-Ping; Jiang, Hao-Wen; Li, Jing-Ya, E-mail:; Nan, Fa-Jun, E-mail:; Li, Jia, E-mail:


    AMP-activated protein kinase (AMPK), which is a pivotal guardian of whole-body energy metabolism, has become an attractive therapeutic target for metabolic syndrome. Previously, using a homogeneous scintillation proximity assay, we identified the small-molecule AMPK activator C24 from an optimization based on the original allosteric activator PT1. In this paper, the AMPK activation mechanism of C24 and its potential beneficial effects on glucose and lipid metabolism on db/db mice were investigated. C24 allosterically stimulated inactive AMPK α subunit truncations and activated AMPK heterotrimers by antagonizing autoinhibition. In primary hepatocytes, C24 increased the phosphorylation of AMPK downstream target acetyl-CoA carboxylase dose-dependently without changing intracellular AMP/ATP ratio, indicating its allosteric activation in cells. Through activating AMPK, C24 decreased glucose output by down-regulating mRNA levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) in primary hepatocytes. C24 also decreased the triglyceride and cholesterol contents in HepG2 cells. Due to its improved bioavailability, chronic oral treatment with multiple doses of C24 significantly reduced blood glucose and lipid levels in plasma, and improved the glucose tolerance of diabetic db/db mice. The hepatic transcriptional levels of PEPCK and G6Pase were reduced. These results demonstrate that this orally effective activator of AMPK represents a novel approach to the treatment of metabolic syndrome. - Highlights: • C24 activates AMPK through antagonizing autoinhibition within α subunit. • C24 activates AMPK in hepatocytes and decreases glucose output via AMPK. • C24 exerts beneficial effects on diabetic db/db mice. • C24 represents a novel therapeutic for treatment of metabolic syndrome.

  5. A Pipeline for Screening Small Molecules with Growth Inhibitory Activity against Burkholderia cenocepacia.

    Directory of Open Access Journals (Sweden)

    Carrie Selin

    Full Text Available Infections with the bacteria Burkholderia cepacia complex (Bcc are very difficult to eradicate in cystic fibrosis patients due the intrinsic resistance of Bcc to most available antibiotics and the emergence of multiple antibiotic resistant strains during antibiotic treatment. In this work, we used a whole-cell based assay to screen a diverse collection of small molecules for growth inhibitors of a relevant strain of Bcc, B. cenocepacia K56-2. The primary screen used bacterial growth in 96-well plate format and identified 206 primary actives among 30,259 compounds. From 100 compounds with no previous record of antibacterial activity secondary screening and data mining selected a total of Bce bioactives that were further analyzed. An experimental pipeline, evaluating in vitro antibacterial and antibiofilm activity, toxicity and in vivo antibacterial activity using C. elegans was used for prioritizing compounds with better chances to be further investigated as potential Bcc antibacterial drugs. This high throughput screen, along with the in vitro and in vivo analysis highlights the utility of this experimental method to quickly identify bioactives as a starting point of antibacterial drug discovery.

  6. Dissecting allosteric effects of activator-coactivator complexes using a covalent small molecule ligand. (United States)

    Wang, Ningkun; Lodge, Jean M; Fierke, Carol A; Mapp, Anna K


    Allosteric binding events play a critical role in the formation and stability of transcriptional activator-coactivator complexes, perhaps in part due to the often intrinsically disordered nature of one or more of the constituent partners. The kinase-inducible domain interacting (KIX) domain of the master coactivator CREB binding protein/p300 is a conformationally dynamic domain that complexes with transcriptional activators at two discrete binding sites in allosteric communication. The complexation of KIX with the transcriptional activation domain of mixed-lineage leukemia protein leads to an enhancement of binding by the activation domain of CREB (phosphorylated kinase-inducible domain of CREB) to the second site. A transient kinetic analysis of the ternary complex formation aided by small molecule ligands that induce positive or negative cooperative binding reveals that positive cooperativity is largely governed by stabilization of the bound complex as indicated by a decrease in koff. Thus, this suggests the increased binding affinity for the second ligand is not due to an allosteric creation of a more favorable binding interface by the first ligand. This is consistent with data from us and from others indicating that the on rates of conformationally dynamic proteins approach the limits of diffusion. In contrast, negative cooperativity is manifested by alterations in both kon and koff, suggesting stabilization of the binary complex.

  7. Small molecule inhibition of 6-phosphofructo-2-kinase suppresses t cell activation

    Directory of Open Access Journals (Sweden)

    Telang Sucheta


    Full Text Available Abstract Background T cell activation is associated with a rapid increase in intracellular fructose-2,6-bisphosphate (F2,6BP, an allosteric activator of the glycolytic enzyme, 6-phosphofructo-1-kinase. The steady state concentration of F2,6BP in T cells is dependent on the expression of the bifunctional 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatases (PFKFB1-4 and the fructose-2,6-bisphosphatase, TIGAR. Of the PFKFB family of enzymes, PFKFB3 has the highest kinase:bisphosphatase ratio and has been demonstrated to be required for T cell proliferation. A small molecule antagonist of PFKFB3, 3-(3-pyridinyl-1-(4-pyridinyl-2-propen-1-one (3PO, recently has been shown to reduce F2,6BP synthesis, glucose uptake and proliferation in transformed cells. We hypothesized that the induction of PFKFB3 expression may be required for the stimulation of glycolysis in T cells and that exposure to the PFKFB3 antagonist, 3PO, would suppress T cell activation. Methods We examined PFKFB1-4 and TIGAR expression and F2,6BP concentration in purified CD3+ T cells stimulated with microbead-conjugated agonist antibodies specific for CD3 and the co-stimulatory receptor, CD28. We then determined the effect of 3PO on anti-CD3/anti-CD28-induced T cell activation, F2,6BP synthesis, 2-[1-14C]-deoxy-d-glucose uptake, lactate secretion, TNF-α secretion and proliferation. Finally, we examined the effect of 3PO administration on the development of delayed type hypersensitivity to methylated BSA and on imiquimod-induced psoriasis in mice. Results We found that purified human CD3+ T cells express PFKFB2, PFKFB3, PFKFB4 and TIGAR, and that anti-CD3/anti-CD28 conjugated microbeads stimulated a >20-fold increase in F2,6BP with a coincident increase in protein expression of the PFKFB3 family member and a decrease in TIGAR protein expression. We then found that exposure to the PFKFB3 small molecule antagonist, 3PO (1–10 μM, markedly attenuated the stimulation of F2,6BP

  8. Crystallographic structure of a small molecule SIRT1 activator-enzyme complex (United States)

    Dai, Han; Case, April W.; Riera, Thomas V.; Considine, Thomas; Lee, Jessica E.; Hamuro, Yoshitomo; Zhao, Huizhen; Jiang, Yong; Sweitzer, Sharon M.; Pietrak, Beth; Schwartz, Benjamin; Blum, Charles A.; Disch, Jeremy S.; Caldwell, Richard; Szczepankiewicz, Bruce; Oalmann, Christopher; Yee Ng, Pui; White, Brian H.; Casaubon, Rebecca; Narayan, Radha; Koppetsch, Karsten; Bourbonais, Francis; Wu, Bo; Wang, Junfeng; Qian, Dongming; Jiang, Fan; Mao, Cheney; Wang, Minghui; Hu, Erding; Wu, Joe C.; Perni, Robert B.; Vlasuk, George P.; Ellis, James L.


    SIRT1, the founding member of the mammalian family of seven NAD+-dependent sirtuins, is composed of 747 amino acids forming a catalytic domain and extended N- and C-terminal regions. We report the design and characterization of an engineered human SIRT1 construct (mini-hSIRT1) containing the minimal structural elements required for lysine deacetylation and catalytic activation by small molecule sirtuin-activating compounds (STACs). Using this construct, we solved the crystal structure of a mini-hSIRT1-STAC complex, which revealed the STAC-binding site within the N-terminal domain of hSIRT1. Together with hydrogen-deuterium exchange mass spectrometry (HDX-MS) and site-directed mutagenesis using full-length hSIRT1, these data establish a specific STAC-binding site and identify key intermolecular interactions with hSIRT1. The determination of the interface governing the binding of STACs with human SIRT1 facilitates greater understanding of STAC activation of this enzyme, which holds significant promise as a therapeutic target for multiple human diseases.

  9. Small molecule regulation of self-association and catalytic activity in a supramolecular coordination complex. (United States)

    McGuirk, C Michael; Stern, Charlotte L; Mirkin, Chad A


    Herein, we report the synthesis and characterization of the first weak-link approach (WLA) supramolecular construct that employs the small molecule regulation of intermolecular hydrogen bonding interactions for the in situ control of catalytic activity. A biaryl urea group, prone to self-aggregation, was functionalized with a phosphinoalkyl thioether (P,S) hemilabile moiety and incorporated into a homoligated Pt(II) tweezer WLA complex. This urea-containing construct, which has been characterized by a single crystal X-ray diffraction study, can be switched in situ from a rigid fully closed state to a flexible semiopen state via Cl(-) induced changes in the coordination mode at the Pt(II) structural node. FT-IR and (1)H NMR spectroscopy studies were used to demonstrate that while extensive urea self-association persists in the flexible semiopen complex, these interactions are deterred in the rigid, fully closed complex because of geometric and steric restraints. Consequently, the urea moieties in the fully closed complex are able to catalyze a Diels-Alder reaction between cyclopentadiene and methyl vinyl ketone to generate 2-acetyl-5-norbornene. The free urea ligand and the semiopen complex show no such activity. The successful incorporation and regulation of a hydrogen bond donating catalyst in a WLA construct open the doors to a vast and rapidly growing catalogue of allosteric catalysts for applications in the detection and amplification of organic analytes.

  10. Discovery of Novel Small Molecules that Activate Satellite Cell Proliferation and Enhance Repair of Damaged Muscle. (United States)

    Billin, Andrew N; Bantscheff, Marcus; Drewes, Gerard; Ghidelli-Disse, Sonja; Holt, Jason A; Kramer, Henning F; McDougal, Alan J; Smalley, Terry L; Wells, Carrow I; Zuercher, William J; Henke, Brad R


    Skeletal muscle progenitor stem cells (referred to as satellite cells) represent the primary pool of stem cells in adult skeletal muscle responsible for the generation of new skeletal muscle in response to injury. Satellite cells derived from aged muscle display a significant reduction in regenerative capacity to form functional muscle. This decrease in functional recovery has been attributed to a decrease in proliferative capacity of satellite cells. Hence, agents that enhance the proliferative abilities of satellite cells may hold promise as therapies for a variety of pathological settings, including repair of injured muscle and age- or disease-associated muscle wasting. Through phenotypic screening of isolated murine satellite cells, we identified a series of 2,4-diaminopyrimidines (e.g., 2) that increased satellite cell proliferation. Importantly, compound 2 was effective in accelerating repair of damaged skeletal muscle in an in vivo mouse model of skeletal muscle injury. While these compounds were originally prepared as c-Jun N-terminal kinase 1 (JNK-1) inhibitors, structure-activity analyses indicated JNK-1 inhibition does not correlate with satellite cell activity. Screening against a broad panel of kinases did not result in identification of an obvious molecular target, so we conducted cell-based proteomics experiments in an attempt to identify the molecular target(s) responsible for the potentiation of the satellite cell proliferation. These data provide the foundation for future efforts to design improved small molecules as potential therapeutics for muscle repair and regeneration.

  11. Small Molecules Target Carcinogenic Proteins (United States)

    Gradinaru, Claudiu


    An ingenious cellular mechanism of effecting protein localization is prenylation: the covalent attachment of a hydrophobic prenyl group to a protein that facilitates protein association with cell membranes. Fluorescence microscopy was used to investigate whether the oncogenic Stat3 protein can undergo artificial prenylation via high-affinity prenylated small-molecule binding agents and thus be rendered inactive by localization at the plasma membrane instead of nucleus. The measurements were performed on a home-built instrument capable of recording simultaneously several optical parameters (lifetime, polarization, color, etc) and with single-molecule sensitivity. A pH-invariant fluorescein derivative with double moiety was designed to bridge a prenyl group and a small peptide that binds Stat3 with high affinity. Confocal fluorescence images show effective localization of the ligand to the membrane of liposomes. Stat3 predominantly localizes at the membrane only in the presence of the prenylated ligand. Single-molecule FRET (fluorescence resonance energy transfer) between donor-labeled prenylated agents and acceptor-labeled, surface tethered Stat3 protein is used to determine the dynamic heterogeneity of the protein-ligand interaction and follow individual binding-unbinding events in real time. The data indicates that molecules can effect protein localization, validating a therapeutic design that influences protein activity via induced localization.

  12. Small-molecule inhibition of MLL activity by disruption of its interaction with WDR5. (United States)

    Senisterra, Guillermo; Wu, Hong; Allali-Hassani, Abdellah; Wasney, Gregory A; Barsyte-Lovejoy, Dalia; Dombrovski, Ludmila; Dong, Aiping; Nguyen, Kong T; Smil, David; Bolshan, Yuri; Hajian, Taraneh; He, Hao; Seitova, Alma; Chau, Irene; Li, Fengling; Poda, Gennadiy; Couture, Jean-François; Brown, Peter J; Al-Awar, Rima; Schapira, Matthieu; Arrowsmith, Cheryl H; Vedadi, Masoud


    WDR5 (WD40 repeat protein 5) is an essential component of the human trithorax-like family of SET1 [Su(var)3-9 enhancer-of-zeste trithorax 1] methyltransferase complexes that carry out trimethylation of histone 3 Lys4 (H3K4me3), play key roles in development and are abnormally expressed in many cancers. In the present study, we show that the interaction between WDR5 and peptides from the catalytic domain of MLL (mixed-lineage leukaemia protein) (KMT2) can be antagonized with a small molecule. Structural and biophysical analysis show that this antagonist binds in the WDR5 peptide-binding pocket with a Kd of 450 nM and inhibits the catalytic activity of the MLL core complex in vitro. The degree of inhibition was enhanced at lower protein concentrations consistent with a role for WDR5 in directly stabilizing the MLL multiprotein complex. Our data demonstrate inhibition of an important protein-protein interaction and form the basis for further development of inhibitors of WDR5-dependent enzymes implicated in MLL-rearranged leukaemias or other cancers.

  13. Antiviral activity of a small molecule deubiquitinase inhibitor occurs via induction of the unfolded protein response.

    Directory of Open Access Journals (Sweden)

    Jeffrey W Perry

    Full Text Available Ubiquitin (Ub is a vital regulatory component in various cellular processes, including cellular responses to viral infection. As obligate intracellular pathogens, viruses have the capacity to manipulate the ubiquitin (Ub cycle to their advantage by encoding Ub-modifying proteins including deubiquitinases (DUBs. However, how cellular DUBs modulate specific viral infections, such as norovirus, is poorly understood. To examine the role of DUBs during norovirus infection, we used WP1130, a small molecule inhibitor of a subset of cellular DUBs. Replication of murine norovirus in murine macrophages and the human norovirus Norwalk virus in a replicon system were significantly inhibited by WP1130. Chemical proteomics identified the cellular DUB USP14 as a target of WP1130 in murine macrophages, and pharmacologic inhibition or siRNA-mediated knockdown of USP14 inhibited murine norovirus infection. USP14 is a proteasome-associated DUB that also binds to inositol-requiring enzyme 1 (IRE1, a critical mediator of the unfolded protein response (UPR. WP1130 treatment of murine macrophages did not alter proteasome activity but activated the X-box binding protein-1 (XBP-1 through an IRE1-dependent mechanism. In addition, WP1130 treatment or induction of the UPR also reduced infection of other RNA viruses including encephalomyocarditis virus, Sindbis virus, and La Crosse virus but not vesicular stomatitis virus. Pharmacologic inhibition of the IRE1 endonuclease activity partially rescued the antiviral effect of WP1130. Taken together, our studies support a model whereby induction of the UPR through cellular DUB inhibition blocks specific viral infections, and suggest that cellular DUBs and the UPR represent novel targets for future development of broad spectrum antiviral therapies.

  14. Activation of Small Molecules by DyI_2 and Dy

    Institute of Scientific and Technical Information of China (English)


    1 Results The reactivities of dysprosium diiodide and metallic dysprosium toward small molecules are discussed.For instance,DyI2-induced silyl radical reactions are described.The combination of dysprosium diiodide and dichloromethane can serve as an effective methylene transfer reagent for cyclopropanation of unfunctionalized alkenes beyond that possible with other metal-dichloromethane systems.Furthermore,we report that the combination of chlorosilane and metallic Dy can also serve as an effective prom...

  15. Catalytic Activation of Small Molecules. Development and Characterisation of Ruthenium Complexes for Application in Catalysis


    Choi, Jong-Hoo


    In this work, the synthesis, characterisation and catalytic application of ruthenium pincer complexes is presented. In this context, new synthetic strategies are discussed to obtain novel ruthenium pincer dihydrogen complexes. Furthermore, the reactivity of the complexes towards small molecules (e.g. alcohols, boranes, ammonia, amines, nitriles and hydrogen) was observed, delivering fundamental insights into catalytic applications. With the reactivity testing, new borylated B-H-σ-complexes we...

  16. Small Molecules in the Cone Snail Arsenal. (United States)

    Neves, Jorge L B; Lin, Zhenjian; Imperial, Julita S; Antunes, Agostinho; Vasconcelos, Vitor; Olivera, Baldomero M; Schmidt, Eric W


    Cone snails are renowned for producing peptide-based venom, containing conopeptides and conotoxins, to capture their prey. A novel small-molecule guanine derivative with unprecedented features, genuanine, was isolated from the venom of two cone snail species. Genuanine causes paralysis in mice, indicating that small molecules and not just polypeptides may contribute to the activity of cone snail venom.

  17. Transmembrane α-Helix 2 and 7 Are Important for Small Molecule-Mediated Activation of the GLP-1 Receptor

    DEFF Research Database (Denmark)

    Underwood, Christina Rye; Møller Knudsen, Sanne; Schjellerup Wulff, Birgitte;


    , the structurally related small molecule, compound 3, stimulated cAMP production from GLP-1R, but not from the homologous glucagon receptor (GluR). The receptor selectivity encouraged a chimeric receptor approach to identify domains important for compound 3-mediated activation of GLP-1R. A subsegment of the GLP-1R...

  18. Discovery of Small Molecules for Fluorescent Detection of Complement Activation Product C3d. (United States)

    Gorham, Ronald D; Nuñez, Vicente; Lin, Jung-Hsin; Rooijakkers, Suzan H M; Vullev, Valentine I; Morikis, Dimitrios


    Complement activation plays a major role in many acute and chronic inflammatory conditions. C3d, a terminal product of complement activation, remains covalently attached to cells and is an excellent biomarker of complement-mediated inflammation. We employed a virtual high-throughput screening protocol to identify molecules with predicted binding to complement C3d and with intrinsic fluorescence properties to enable detection. Pharmacophore models were developed based on known C3d-ligand interactions and information from computational analysis of structural and molecular dynamics data. Iterative pharmacophore-based virtual screening was performed to identify druglike molecules with physicochemical similarity to the natural C3d ligand CR2. Hits from the pharmacophore screens were docked to C3d and ranked based on predicted binding free energies. Top-ranked molecules were selected for experimental validation of binding affinity to C3d, using microscale thermophoresis, and for their suitability to become molecular imaging agents, using fluorescence spectroscopy. This work serves as a foundation for identifying additional fluorescent molecules with high-affinity for C3d that will subsequently be explored as noninvasive in vivo diagnostics of complement-mediated inflammation, for spatiotemporal monitoring of disease progression, and for targeting therapeutics to sites of inflammation.

  19. Recent advances in small organic molecules as DNA intercalating agents: synthesis, activity, and modeling. (United States)

    Rescifina, Antonio; Zagni, Chiara; Varrica, Maria Giulia; Pistarà, Venerando; Corsaro, Antonino


    The interaction of small molecules with DNA plays an essential role in many biological processes. As DNA is often the target for majority of anticancer and antibiotic drugs, study about the interaction of drug and DNA has a key role in pharmacology. Moreover, understanding the interactions of small molecules with DNA is of prime significance in the rational design of more powerful and selective anticancer agents. Two of the most important and promising targets in cancer chemotherapy include DNA alkylating agents and DNA intercalators. For these last the DNA recognition is a critical step in their anti-tumor action and the intercalation is not only one kind of the interactions in DNA recognition but also a pivotal step of several clinically used anti-tumor drugs such as anthracyclines, acridines and anthraquinones. To push clinical cancer therapy, the discovery of new DNA intercalators has been considered a practical approach and a number of intercalators have been recently reported. The intercalative binding properties of such molecules can also be harnessed as diagnostic probes for DNA structure in addition to DNA-directed therapeutics. Moreover, the problem of intercalation site formation in the undistorted B-DNA of different length and sequence is matter of tremendous importance in molecular modeling studies and, nowadays, three models of DNA intercalation targets have been proposed that account for the binding features of intercalators. Finally, despite DNA being an important target for several drugs, most of the docking programs are validated only for proteins and their ligands. Therefore, a default protocol to identify DNA binding modes which uses a modified canonical DNA as receptor is needed.

  20. Interplay of solvent additive concentration and active layer thickness on the performance of small molecule solar cells. (United States)

    Love, John A; Collins, Samuel D; Nagao, Ikuhiro; Mukherjee, Subhrangsu; Ade, Harald; Bazan, Guillermo C; Nguyen, Thuc-Quyen


    A relationship between solvent additive concentration and active layer thickness in small-molecule solar cells is investigated. Specifically, the additive concentration must scale with the amount of semiconductor material and not as absolute concentration in solution. Devices with a wide range of active layers with thickness up to 200 nm can readily achieve efficiencies close to 6% when the right concentration of additive is used.

  1. Structures of Clostridium Botulinum Neurotoxin Serotype A Light Chain Complexed with Small-Molecule Inhibitors Highlight Active-Site Flexibility

    Energy Technology Data Exchange (ETDEWEB)

    Silvaggi,N.; Boldt, G.; Hixon, M.; Kennedy, J.; Tzipori, S.; Janda, K.; Allen, K.


    The potential for the use of Clostridial neurotoxins as bioweapons makes the development of small-molecule inhibitors of these deadly toxins a top priority. Recently, screening of a random hydroxamate library identified a small-molecule inhibitor of C. botulinum Neurotoxin Serotype A Light Chain (BoNT/A-LC), 4-chlorocinnamic hydroxamate, a derivative of which has been shown to have in vivo efficacy in mice and no toxicity. We describe the X-ray crystal structures of BoNT/A-LC in complexes with two potent small-molecule inhibitors. The structures of the enzyme with 4-chlorocinnamic hydroxamate or 2,4-dichlorocinnamic hydroxamate bound are compared to the structure of the enzyme complexed with L-arginine hydroxamate, an inhibitor with modest affinity. Taken together, this suite of structures provides surprising insights into the BoNT/A-LC active site, including unexpected conformational flexibility at the S1' site that changes the electrostatic environment of the binding pocket. Information gained from these structures will inform the design and optimization of more effective small-molecule inhibitors of BoNT/A-LC.

  2. Activation of CO{sub 2} and related small molecules by neopentyl-derivatized uranium complexes

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Anna-Corina


    This work reports the newly synthesized neopentyl derivatized tris(aryloxide) U{sup III} complex [(({sup nP,Me}ArO){sub 3}tacn)U{sup III}] (1) and its reactivity with small molecules like nitrous oxide (N{sub 2}O), carbon dioxide (CO{sub 2}), and sulfur dioxide (SO{sub 2}). Additionally, a deeper insight into covalency of U-R bonds with R = O, N and the participation of the f-orbitals to bonding are discussed. For this purpose, a large number of characterization methods were used, such as X-ray diffraction analysis, U{sup V}/vis/NIR, IR vibrational, Raman, X-ray absorption, EPR, and {sup 1}H, {sup 15}N, {sup 13}C and {sup 19}F NMR spectroscopy, cyclic voltammetry, SQUID magnetization measurements and DFT calculations. Moreover, all compounds were checked for purity by elemental analysis.

  3. Small-Molecule Inhibition and Activation-Loop Trans-Phosphorylation of the IGF1 Receptor

    Energy Technology Data Exchange (ETDEWEB)

    Wu,J.; Li, W.; Craddock, B.; Foreman, K.; Mulvihill, M.; Ji, Q.; Miller, W.; Hubbard, S.


    The insulin-like growth factor-1 receptor (IGF1R) is a receptor tyrosine kinase (RTK) that has a critical role in mitogenic signalling during embryogenesis and an antiapoptotic role in the survival and progression of many human tumours. Here, we present the crystal structure of the tyrosine kinase domain of IGF1R (IGF1RK), in its unphosphorylated state, in complex with a novel compound, cis-3-[3-(4-methyl-piperazin-l-yl)-cyclobutyl]-1-(2-phenyl-quinolin-7-yl)-imidazo[1, 5-a]pyrazin-8-ylamine (PQIP), which we show is a potent inhibitor of both the unphosphorylated (basal) and phosphorylated (activated) states of the kinase. PQIP interacts with residues in the ATP-binding pocket and in the activation loop, which confers specificity for IGF1RK and the highly related insulin receptor (IR) kinase. In this crystal structure, the IGF1RK active site is occupied by Tyr1135 from the activation loop of an symmetry (two-fold)-related molecule. This dimeric arrangement affords, for the first time, a visualization of the initial trans-phosphorylation event in the activation loop of an RTK, and provides a molecular rationale for a naturally occurring mutation in the activation loop of the IR that causes type II diabetes mellitus.

  4. Small Molecule PET-Radiopharmaceuticals

    NARCIS (Netherlands)

    Elsinga, Philip H.; Dierckx, Rudi A. J. O.


    This review describes several aspects required for the development of small molecule PET-tracers. Design and selection criteria are important to consider before starting to develop novel PET-tracers. Principles and latest trends in C-11 and F-18-radiochemistry are summarized. In addition an update o

  5. Discovery of a small-molecule binder of the oncoprotein gankyrin that modulates gankyrin activity in the cell (United States)

    Chattopadhyay, Anasuya; O'Connor, Cornelius J.; Zhang, Fengzhi; Galvagnion, Celine; Galloway, Warren R. J. D.; Tan, Yaw Sing; Stokes, Jamie E.; Rahman, Taufiq; Verma, Chandra; Spring, David R.; Itzhaki, Laura S.


    Gankyrin is an ankyrin-repeat oncoprotein whose overexpression has been implicated in the development of many cancer types. Elevated gankyrin levels are linked to aberrant cellular events including enhanced degradation of tumour suppressor protein p53, and inhibition of gankyrin activity has therefore been identified as an attractive anticancer strategy. Gankyrin interacts with several partner proteins, and a number of these protein-protein interactions (PPIs) are of relevance to cancer. Thus, molecules that bind the PPI interface of gankyrin and interrupt these interactions are of considerable interest. Herein, we report the discovery of a small molecule termed cjoc42 that is capable of binding to gankyrin. Cell-based experiments demonstrate that cjoc42 can inhibit gankyrin activity in a dose-dependent manner: cjoc42 prevents the decrease in p53 protein levels normally associated with high amounts of gankyrin, and it restores p53-dependent transcription and sensitivity to DNA damage. The results represent the first evidence that gankyrin is a “druggable” target with small molecules.

  6. PdM (M = Pt, Au) bimetallic alloy nanowires with enhanced electrocatalytic activity for electro-oxidation of small molecules

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Chengzhou; Guo, Shaojun; Dong, Shaojun [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022 (China)


    A facile and general method has been developed to synthesize well-defined PdPt and PdAu alloy nanowires, which exhibit significantly enhanced activity towards small molecules, such as ethanol, methanol, and glucose electro-oxidation in an alkaline medium. Considering the important role of one-dimensional alloy nanowires in electrocatalytic systems, the present Pd-based alloy nanostructures could offer a promising new class of advanced electrocatalysts for direct alcohol fuel cells and electrochemical sensors. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. An Intramolecular Silylene Borane Capable of Facile Activation of Small Molecules, Including Metal-Free Dehydrogenation of Water. (United States)

    Mo, Zhenbo; Szilvási, Tibor; Zhou, Yu-Peng; Yao, Shenglai; Driess, Matthias


    The first single-component N-heterocyclic silylene borane 1 (LSi-R-BMes2 ; L=PhC(N(t) Bu)2 ; R=1,12-xanthendiyl spacer; Mes=2,4,6-Me3 C6 H2 ), acting as a frustrated Lewis pair (FLP) in small-molecule activation, can be synthesized in 65 % yields. Its HOMO is largely localized at the silicon(II) atom and the LUMO has mainly boron 2p character. In small-molecule activation 1 allows access to the intramolecular silanone-borane 3 featuring a Si=O→B interaction through reaction with O2 , N2 O, or CO2 , and formation of silanethione borane 4 from reaction with S8 . The Si(II) center in 1 undergoes immediate hydrogenation if exposed to H2 at 1 atm pressure in benzene, affording the silane borane 5-H2 , L(H2 )Si-R-BMes2 . Remarkably, no H2 activation occurs if the single silylene LSiPh and Mes3 B intermolecularly separated are exposed to dihydrogen. Unexpectedly, the pre-organized Si-B separation in 1 enables a metal-free dehydrogenation of H2 O to give the silanone-borane 3 as reactive intermediate.

  8. Protein Scaffolding for Small Molecule Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Baker, David [Univ. of Washington, Seattle, WA (United States)


    We aim to design hybrid catalysts for energy production and storage that combine the high specificity, affinity, and tunability of proteins with the potent chemical reactivities of small organometallic molecules. The widely used Rosetta and RosettaDesign methodologies will be extended to model novel protein / small molecule catalysts in which one or many small molecule active centers are supported and coordinated by protein scaffolding. The promise of such hybrid molecular systems will be demonstrated with the nickel-phosphine hydrogenase of DuBois et. al.We will enhance the hydrogenase activity of the catalyst by designing protein scaffolds that incorporate proton relays and systematically modulate the local environment of the catalyticcenter. In collaboration with DuBois and Shaw, the designs will be experimentally synthesized and characterized.

  9. Enzyme kinetics and distinct modulation of the protein kinase N family of kinases by lipid activators and small molecule inhibitors (United States)

    Falk, Matthew D.; Liu, Wei; Bolaños, Ben; Unsal-Kacmaz, Keziban; Klippel, Anke; Grant, Stephan; Brooun, Alexei; Timofeevski, Sergei


    The PKN (protein kinase N) family of Ser/Thr protein kinases regulates a diverse set of cellular functions, such as cell migration and cytoskeletal organization. Inhibition of tumour PKN activity has been explored as an oncology therapeutic approach, with a PKN3-targeted RNAi (RNA interference)-derived therapeutic agent in Phase I clinical trials. To better understand this important family of kinases, we performed detailed enzymatic characterization, determining the kinetic mechanism and lipid sensitivity of each PKN isoform using full-length enzymes and synthetic peptide substrate. Steady-state kinetic analysis revealed that PKN1–3 follows a sequential ordered Bi–Bi kinetic mechanism, where peptide substrate binding is preceded by ATP binding. This kinetic mechanism was confirmed by additional kinetic studies for product inhibition and affinity of small molecule inhibitors. The known lipid effector, arachidonic acid, increased the catalytic efficiency of each isoform, mainly through an increase in kcat for PKN1 and PKN2, and a decrease in peptide KM for PKN3. In addition, a number of PKN inhibitors with various degrees of isoform selectivity, including potent (Ki<10 nM) and selective PKN3 inhibitors, were identified by testing commercial libraries of small molecule kinase inhibitors. This study provides a kinetic framework and useful chemical probes for understanding PKN biology and the discovery of isoform-selective PKN-targeted inhibitors. PMID:27919031

  10. High quality, small molecule-activity datasets for kinase research [version 3; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Rajan Sharma


    Full Text Available Kinases regulate cell growth, movement, and death. Deregulated kinase activity is a frequent cause of disease. The therapeutic potential of kinase inhibitors has led to large amounts of published structure activity relationship (SAR data. Bioactivity databases such as the Kinase Knowledgebase (KKB, WOMBAT, GOSTAR, and ChEMBL provide researchers with quantitative data characterizing the activity of compounds across many biological assays. The KKB, for example, contains over 1.8M kinase structure-activity data points reported in peer-reviewed journals and patents. In the spirit of fostering methods development and validation worldwide, we have extracted and have made available from the KKB 258K structure activity data points and 76K associated unique chemical structures across eight kinase targets. These data are freely available for download within this data note.

  11. Small Molecule APY606 Displays Extensive Antitumor Activity in Pancreatic Cancer via Impairing Ras-MAPK Signaling (United States)

    Guo, Na; Liu, Zuojia; Zhao, Wenjing; Wang, Erkang; Wang, Jin


    Pancreatic cancer has been found with abnormal expression or mutation in Ras proteins. Oncogenic Ras activation exploits their extensive signaling reach to affect multiple cellular processes, in which the mitogen-activated protein kinase (MAPK) signaling exerts important roles in tumorigenesis. Therapies targeted Ras are thus of major benefit for pancreatic cancer. Although small molecule APY606 has been successfully picked out by virtual drug screening based on Ras target receptor, its in-depth mechanism remains to be elucidated. We herein assessed the antitumor activity of APY606 against human pancreatic cancer Capan-1 and SW1990 cell lines and explored the effect of Ras-MAPK and apoptosis-related signaling pathway on the activity of APY606. APY606 treatment resulted in a dose- and time-dependent inhibition of cancer cell viability. Additionally, APY606 exhibited strong antitumor activity, as evidenced not only by reduction in tumor cell invasion, migration and mitochondrial membrane potential but also by alteration in several apoptotic indexes. Furthermore, APY606 treatment directly inhibited Ras-GTP and the downstream activation of MAPK, which resulted in the down-regulation of anti-apoptotic protein Bcl-2, leading to the up-regulation of mitochondrial apoptosis pathway-related proteins (Bax, cytosolic Cytochrome c and Caspase 3) and of cyclin-dependent kinase 2 and Cyclin A, E. These data suggest that impairing Ras-MAPK signaling is a novel mechanism of action for APY606 during therapeutic intervention in pancreatic cancer. PMID:27223122

  12. Modulation of Pantothenate Kinase 3 Activity by Small Molecules that Interact with the Substrate/Allosteric Regulatory Domain

    Energy Technology Data Exchange (ETDEWEB)

    Leonardi, Roberta; Zhang, Yong-Mei; Yun, Mi-Kyung; Zhou, Ruobing; Zeng, Fu-Yue; Lin, Wenwei; Cui, Jimmy; Chen, Taosheng; Rock, Charles O.; White, Stephen W.; Jackowski, Suzanne (SJCH)


    Pantothenate kinase (PanK) catalyzes the rate-controlling step in coenzyme A (CoA) biosynthesis. PanK3 is stringently regulated by acetyl-CoA and uses an ordered kinetic mechanism with ATP as the leading substrate. Biochemical analysis of site-directed mutants indicates that pantothenate binds in a tunnel adjacent to the active site that is occupied by the pantothenate moiety of the acetyl-CoA regulator in the PanK3 acetyl-CoA binary complex. A high-throughput screen for PanK3 inhibitors and activators was applied to a bioactive compound library. Thiazolidinediones, sulfonylureas and steroids were inhibitors, and fatty acyl-amides and tamoxifen were activators. The PanK3 activators and inhibitors either stimulated or repressed CoA biosynthesis in HepG2/C3A cells. The flexible allosteric acetyl-CoA regulatory domain of PanK3 also binds the substrates, pantothenate and pantetheine, and small molecule inhibitors and activators to modulate PanK3 activity.

  13. Approaches to capturing and designing biologically active small molecules produced by uncultured microbes. (United States)

    Piel, Jörn


    Bacteria are one of the most important sources of bioactive natural products for drug discovery. Yet, in most habitats only a small percentage of all existing prokaryotes is amenable to cultivation and chemical study. There is strong evidence that the uncultivated diversity represents an enormous resource of novel biosynthetic enzymes and secondary metabolites. In addition, many animal-derived drug candidates that are structurally characterized but difficult to access seem to be produced by uncultivated, symbiotic bacteria. This review provides an overview about established and emerging techniques for the investigation and exploitation of the environmental metabolome. These include metagenomic library construction and screening, heterologous expression, community sequencing, and single-cell methods. Such tools, the advantages and shortcomings of which are discussed, have just begun to reveal the full metabolic potential of free-living and symbiotic bacteria, providing exciting new avenues for natural product research and environmental microbiology.

  14. Cellular Activity of New Small Molecule Protein Arginine Deiminase 3 (PAD3) Inhibitors. (United States)

    Jamali, Haya; Khan, Hasan A; Tjin, Caroline C; Ellman, Jonathan A


    The protein arginine deiminases (PADs) catalyze the post-translational deimination of arginine side chains. Multiple PAD isozymes have been characterized, and abnormal PAD activity has been associated with several human disease states. PAD3 has been characterized as a modulator of cell growth via apoptosis inducing factor and has been implicated in the neurodegenerative response to spinal cord injury. Here, we describe the design, synthesis, and evaluation of conformationally constrained versions of the potent and selective PAD3 inhibitor 2. The cell activity of representative inhibitors in this series was also demonstrated for the first time by rescue of thapsigargin-induced cell death in PAD3-expressing HEK293T cells.

  15. Screening a Commercial Library of Pharmacologically Active Small Molecules against Staphylococcus aureus Biofilms. (United States)

    Torres, Nelson S; Abercrombie, Johnathan J; Srinivasan, Anand; Lopez-Ribot, Jose L; Ramasubramanian, Anand K; Leung, Kai P


    It is now well established that bacterial infections are often associated with biofilm phenotypes that demonstrate increased resistance to common antimicrobials. Further, due to the collective attrition of new antibiotic development programs by the pharmaceutical industries, drug repurposing is an attractive alternative. In this work, we screened 1,280 existing commercially available drugs in the Prestwick Chemical Library, some with previously unknown antimicrobial activity, against Staphylococcus aureus, one of the commonly encountered causative pathogens of burn and wound infections. From the primary screen of the entire Prestwick Chemical Library at a fixed concentration of 10 μM, 104 drugs were found to be effective against planktonic S. aureus strains, and not surprisingly, these were mostly antimicrobials and antiseptics. The activity of 18 selected repurposing candidates, that is, drugs that show antimicrobial activity that are not already considered antimicrobials, observed in the primary screen was confirmed in dose-response experiments. Finally, a subset of nine of these drug candidates was tested against preformed biofilms of S. aureus We found that three of these drugs, niclosamide, carmofur, and auranofin, possessed antimicrobial activity against preformed biofilms, making them attractive candidates for repurposing as novel antibiofilm therapies.

  16. A target-based high throughput screen yields Trypanosoma brucei hexokinase small molecule inhibitors with antiparasitic activity.

    Directory of Open Access Journals (Sweden)

    Elizabeth R Sharlow

    Full Text Available BACKGROUND: The parasitic protozoan Trypanosoma brucei utilizes glycolysis exclusively for ATP production during infection of the mammalian host. The first step in this metabolic pathway is mediated by hexokinase (TbHK, an enzyme essential to the parasite that transfers the gamma-phospho of ATP to a hexose. Here we describe the identification and confirmation of novel small molecule inhibitors of bacterially expressed TbHK1, one of two TbHKs expressed by T. brucei, using a high throughput screening assay. METHODOLOGY/PRINCIPAL FINDINGS: Exploiting optimized high throughput screening assay procedures, we interrogated 220,233 unique compounds and identified 239 active compounds from which ten small molecules were further characterized. Computation chemical cluster analyses indicated that six compounds were structurally related while the remaining four compounds were classified as unrelated or singletons. All ten compounds were approximately 20-17,000-fold more potent than lonidamine, a previously identified TbHK1 inhibitor. Seven compounds inhibited T. brucei blood stage form parasite growth (0.03activity. None of the compounds displayed structural similarity to known hexokinase inhibitors or human African trypanosomiasis therapeutics. CONCLUSIONS/SIGNIFICANCE: The novel chemotypes identified here could represent leads for future therapeutic development against the African trypanosome.

  17. Genome-wide signatures of transcription factor activity: connecting transcription factors, disease, and small molecules.

    Directory of Open Access Journals (Sweden)

    Jing Chen

    Full Text Available Identifying transcription factors (TF involved in producing a genome-wide transcriptional profile is an essential step in building mechanistic model that can explain observed gene expression data. We developed a statistical framework for constructing genome-wide signatures of TF activity, and for using such signatures in the analysis of gene expression data produced by complex transcriptional regulatory programs. Our framework integrates ChIP-seq data and appropriately matched gene expression profiles to identify True REGulatory (TREG TF-gene interactions. It provides genome-wide quantification of the likelihood of regulatory TF-gene interaction that can be used to either identify regulated genes, or as genome-wide signature of TF activity. To effectively use ChIP-seq data, we introduce a novel statistical model that integrates information from all binding "peaks" within 2 Mb window around a gene's transcription start site (TSS, and provides gene-level binding scores and probabilities of regulatory interaction. In the second step we integrate these binding scores and regulatory probabilities with gene expression data to assess the likelihood of True REGulatory (TREG TF-gene interactions. We demonstrate the advantages of TREG framework in identifying genes regulated by two TFs with widely different distribution of functional binding events (ERα and E2f1. We also show that TREG signatures of TF activity vastly improve our ability to detect involvement of ERα in producing complex diseases-related transcriptional profiles. Through a large study of disease-related transcriptional signatures and transcriptional signatures of drug activity, we demonstrate that increase in statistical power associated with the use of TREG signatures makes the crucial difference in identifying key targets for treatment, and drugs to use for treatment. All methods are implemented in an open-source R package treg. The package also contains all data used in the analysis

  18. A structure-activity relationship study of small-molecule inhibitors of GLI1-mediated transcription. (United States)

    Actis, Marcelo; Connelly, Michele C; Mayasundari, Anand; Punchihewa, Chandanamali; Fujii, Naoaki


    We have previously reported ketoprofen amide compounds as inhibitors of GLI1-mediated transcription, an essential down-stream element of the Hedgehog (Hh) pathway. These compounds inhibited Gli-luciferase reporter in C3H10T1/2 cells that were exogenously transfected with GLI1 and in Rh30 cells that endogenously overexpress GLI1. Here we have designed new derivatives of these compounds aiming to explore the structure-activation relationship (SAR). By replacing the ketone carbonyl group of the ketoprofen moiety with an ether, amide, sulfonamide, or sulfone, we found several new compounds that are equipotent to the ketoprofen amide compounds. Among them, sulfone 30 inhibited Gli-luciferase reporter in C3H10T1/2 cells that were exogenously transfected with GLI1 and in Rh30 cells that endogenously overexpress GLI1.

  19. Probing binding and cellular activity of pyrrolidinone and piperidinone small molecules targeting the urokinase receptor. (United States)

    Mani, Timmy; Liu, Degang; Zhou, Donghui; Li, Liwei; Knabe, William Eric; Wang, Fang; Oh, Kyungsoo; Meroueh, Samy O


    The urokinase receptor (uPAR) is a cell-surface protein that is part of an intricate web of transient and tight protein interactions that promote cancer cell invasion and metastasis. Here, we evaluate the binding and biological activity of a new class of pyrrolidinone and piperidinone compounds, along with derivatives of previously-identified pyrazole and propylamine compounds. Competition assays revealed that the compounds displace a fluorescently labeled peptide (AE147-FAM) with inhibition constant (Ki ) values ranging from 6 to 63 μM. Structure-based computational pharmacophore analysis followed by extensive explicit-solvent molecular dynamics (MD) simulations and free energy calculations suggested the pyrazole-based and piperidinone-based compounds adopt different binding modes, despite their similar two-dimensional structures. In cells, pyrazole-based compounds showed significant inhibition of breast adenocarcinoma (MDA-MB-231) and pancreatic ductal adenocarcinoma (PDAC) cell proliferation, but piperidinone-containing compounds exhibited no cytotoxicity even at concentrations of 100 μM. One pyrazole-based compound impaired MDA-MB-231 invasion, adhesion, and migration in a concentration-dependent manner, while the piperidinone inhibited only invasion. The pyrazole derivative inhibited matrix metalloprotease-9 (gelatinase) activity in a concentration-dependent manner, while the piperidinone showed no effect suggesting different mechanisms for inhibition of cell invasion. Signaling studies further highlighted these differences, showing that pyrazole compounds completely inhibited ERK phosphorylation and impaired HIF1α and NF-κB signaling, while pyrrolidinones and piperidinones had no effect. Annexin V staining suggested that the effect of the pyrazole-based compound on proliferation was due to cell killing through an apoptotic mechanism. The compounds identified represent valuable leads in the design of further derivatives with higher affinities and

  20. Specific small-molecule activator of Aurora kinase A induces autophosphorylation in a cell-free system. (United States)

    Kishore, A Hari; Vedamurthy, B M; Mantelingu, K; Agrawal, Shipra; Reddy, B A Ashok; Roy, Siddhartha; Rangappa, K S; Kundu, Tapas K


    Aurora kinases are essential for chromosomal segregation and cell division and thereby important for maintaining the proper genomic integrity. There are three classes of aurora kinases in humans: A, B, and C. Aurora kinase A is frequently overexpressed in various cancers. The link of the overexpression and tumorigenesis is yet to be understood. By employing virtual screening, we have found that anacardic acid, a pentadecane aliphatic chain containing hydroxylcarboxylic acid, from cashew nut shell liquid could be docked in Aurora kinases A and B. Remarkably, we found that anacardic acid could potently activate the Aurora kinase A mediated phosphorylation of histone H3, but at a similar concentration the activity of aurora kinase B remained unaffected in vitro. Mechanistically, anacardic acid induces the structural changes and also the autophosphorylation of the aurora kinase A to enhance the enzyme activity. This data thus indicate anacardic acid as the first small-molecule activator of Aurora kinase, which could be highly useful for probing the function of hyperactive (overexpressed) Aurora kinase A.

  1. Dynamics of Activated Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Mullin, Amy S. [Univ. of Maryland, College Park, MD (United States)


    Experimental studies have been performed to investigate the collisional energy transfer processes of gas-phase molecules that contain large amounts of internal energy. Such molecules are prototypes for molecules under high temperature conditions relevant in combustion and information about their energy transfer mechanisms is needed for a detailed understanding and modeling of the chemistry. We use high resolution transient IR absorption spectroscopy to measure the full, nascent product distributions for collisions of small bath molecules that relax highly vibrationally excited pyrazine molecules with E=38000 cm-1 of vibrational energy. To perform these studies, we developed new instrumentation based on modern IR light sources to expand our experimental capabilities to investigate new molecules as collision partners. This final report describes our research in four areas: the characterization of a new transient absorption spectrometer and the results of state-resolved collision studies of pyrazine(E) with HCl, methane and ammonia. Through this research we have gained fundamental new insights into the microscopic details of relatively large complex molecules at high energy as they undergo quenching collisions and redistribute their energy.

  2. Activation of Relaxin Family Receptor 1 from different mammalian species by relaxin peptide and small molecule agonist ML290

    Directory of Open Access Journals (Sweden)

    Zaohua eHuang


    Full Text Available Relaxin peptide (RLN, which signals through the relaxin family peptide 1 (RXFP1 GPCR receptor, has shown therapeutic effects in an acute heart failure clinical trial. We have identified a small molecule agonist of human RXFP1, ML290; however, it does not activate the mouse receptor. To find a suitable animal model for ML290 testing and to gain mechanistic insights into the interaction of various ligands with RXFP1, we have cloned rhesus macaque, pig, rabbit, and guinea pig RXFP1s and analyzed their activation by RLN and ML290. HEK293T cells expressing macaque or pig RXFP1 responded to relaxin and ML290 treatment as measured by an increase of cAMP production. Guinea pig RXFP1 responded to relaxin but had very low response to ML290 treatment only at highest concentrations used. The rabbit RXFP1 amino acid sequence was the most divergent, with a number of unique substitutions within the ectodomain and the 7-transmembrane domain (7TM. Two splice variants of rabbit RXFP1 derived through alternative splicing of the forth exon were identified. In contrast to the other species, rabbit RXFP1s were activated by ML290, but not with human, pig, mouse, or rabbit relaxins. Using FLAG-tagged constructs, we have shown that both rabbit RXFP1 variants are expressed on the cell surface. No binding of human Eu-labeled relaxin to rabbit RXFP1 was detected, suggesting that in this species RXFP1 might be non-functional. We used chimeric rabbit-human and guinea pig-human constructs to identify regions important for RLN or ML290 receptor activation. Chimeras with the human ectodomain and rabbit 7TM domain were activated by RLN, whereas substitution of part of the guinea pig 7TM domain with the human sequence only partially restored ML290 activation, confirming the allosteric mode of action for the two ligands. Our data demonstrate that macaque and pig models can be used for ML290 testing.

  3. Fluorescence Polarization Assays in Small Molecule Screening (United States)

    Lea, Wendy A.; Simeonov, Anton


    Importance of the field Fluorescence polarization (FP) is a homogeneous method that allows rapid and quantitative analysis of diverse molecular interactions and enzyme activities. This technique has been widely utilized in clinical and biomedical settings, including the diagnosis of certain diseases and monitoring therapeutic drug levels in body fluids. Recent developments in the field has been symbolized by the facile adoption of FP in high-throughput screening (HTS) and small molecule drug discovery of an increasing range of target classes. Areas covered in this review The article provides a brief overview on the theoretical foundation of FP, followed by updates on recent advancements in its application for various drug target classes, including G-protein coupled receptors (GPCRs), enzymes and protein-protein interactions (PPIs). The strengths and weaknesses of this method, practical considerations in assay design, novel applications, and future directions are also discussed. What the reader will gain The reader will be informed of the most recent advancements and future directions of FP application to small molecule screening. Take home message In addition to its continued utilization in high-throughput screening, FP has expanded into new disease and target areas and has been marked by increased use of labeled small molecule ligands for receptor binding studies. PMID:22328899

  4. Hydrophobic Porous Material Adsorbs Small Organic Molecules (United States)

    Sharma, Pramod K.; Hickey, Gregory S.


    Composite molecular-sieve material has pore structure designed specifically for preferential adsorption of organic molecules for sizes ranging from 3 to 6 angstrom. Design based on principle that contaminant molecules become strongly bound to surface of adsorbent when size of contaminant molecules is nearly same as that of pores in adsorbent. Material used to remove small organic contaminant molecules from vacuum systems or from enclosed gaseous environments like closed-loop life-support systems.

  5. Discovery and Characterization of a Cell-Permeable, Small-Molecule c-Abl Kinase Activator that Binds to the Myristoyl Binding Site

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jingsong; Campobasso, Nino; Biju, Mangatt P.; Fisher, Kelly; Pan, Xiao-Qing; Cottom, Josh; Galbraith, Sarah; Ho, Thau; Zhang, Hong; Hong, Xuan; Ward, Paris; Hofmann, Glenn; Siegfried, Brett; Zappacosta, Francesca; Washio, Yoshiaki; Cao, Ping; Qu, Junya; Bertrand, Sophie; Wang, Da-Yuan; Head, Martha S.; Li, Hu; Moores, Sheri; Lai, Zhihong; Johanson, Kyung; Burton, George; Erickson-Miller, Connie; Simpson, Graham; Tummino, Peter; Copeland, Robert A.; Oliff, Allen (GSKPA)


    c-Abl kinase activity is regulated by a unique mechanism involving the formation of an autoinhibited conformation in which the N-terminal myristoyl group binds intramolecularly to the myristoyl binding site on the kinase domain and induces the bending of the {alpha}I helix that creates a docking surface for the SH2 domain. Here, we report a small-molecule c-Abl activator, DPH, that displays potent enzymatic and cellular activity in stimulating c-Abl activation. Structural analyses indicate that DPH binds to the myristoyl binding site and prevents the formation of the bent conformation of the {alpha}I helix through steric hindrance, a mode of action distinct from the previously identified allosteric c-Abl inhibitor, GNF-2, that also binds to the myristoyl binding site. DPH represents the first cell-permeable, small-molecule tool compound for c-Abl activation.

  6. Structure–activity relationships of a small-molecule inhibitor of the PDZ domain of PICK1

    DEFF Research Database (Denmark)

    Bach, Anders; Stuhr-Hansen, Nicolai; Thorsen, Thor S.


    Recently, we described the first small-molecule inhibitor, (E)-ethyl 2-cyano-3-(3,4-dichlorophenyl)acryloylcarbamate (1), of the PDZ domain of protein interacting with Ca-kinase 1 (PICK1), a potential drug target against brain ischemia, pain and cocaine addiction. Herein, we explore structure......, docking studies were used to correlate biological affinities with structural considerations for ligand–protein interactions. The most potent analogue obtained in this study showed an improvement in affinity compared to 1 and is currently a lead in further studies of PICK1 inhibition....

  7. Small molecules for big tasks

    Institute of Scientific and Technical Information of China (English)

    Jiarui Wu


    @@ One of the most important achievements in the post-genome era is discovery of microRNAs (miRNAs), which widely exist from simple-genome organisms such as viruses and bacteria to complexgenome organisms such as plants and animals.miRNAs are single-stranded non-coding RNAs of 18-25 nucleotides in length, which are generated from larger precursors that are transcribed from noncoding genes.As a new type of regulatory molecules, miRNAs present unique features in regulating gene and its products, including rapidly turning off protein production, reversibly, and compartmentalized regulating gene expression.

  8. Small-Molecule Carbohydrate-Based Immunostimulants. (United States)

    Marzabadi, Cecilia H; Franck, Richard W


    In this review, we discuss small-molecule, carbohydrate-based immunostimulants that target Toll-like receptor 4 (TLR-4) and cluster of differentiation 1D (CD1d) receptors. The design and use of these molecules in immunotherapy as well as results from their use in clinical trials are described. How these molecules work and their utilization as vaccine adjuvants are also discussed. Future applications and extensions for the use of these analogues as therapeutic agents will be outlined.

  9. Raman and surface enhanced Raman spectroscopic studies of specific, small molecule activator of histone acetyltransferase p300 (United States)

    Kundu, Partha P.; Pavan Kumar, G. V.; Mantelingu, Kempegowda; Kundu, Tapas K.; Narayana, Chandrabhas


    We report for the first time, the Raman and surface enhanced Raman scattering (SERS) studies of N-(4-chloro-3-trifluoromethyl-phenyl)-2-ethoxy-benzamide (CTB). This molecule is specific activator of human histone acetyltransferase (HAT), p300, and serves as lead molecule to design anti-neoplastic therapeutics. A detailed Raman and SERS band assignments have been performed for CTB, which are compared with the density functional theory calculations. The observed red shift of N sbnd H stretching frequency from the computed wavenumber indicates the weakening of N sbnd H bond resulting from proton transfer to the neighboring oxygen atom. We observe Ag sbnd N vibrational mode at 234 cm -1 in SERS of CTB. This indicates there is a metal-molecule bond leading to chemical enhancement in SERS. We also observe, enhancement in the modes pertaining to substituted benzene rings and methyl groups. Based on SERS analysis we propose the adsorption sites and the orientation of CTB on silver surface.

  10. Teaching with the Case Study Method to Promote Active Learning in a Small Molecule Crystallography Course for Chemistry Students (United States)

    Campbell, Michael G.; Powers, Tamara M.; Zheng, Shao-Liang


    Implementing the case study method in a practical X-ray crystallography course designed for graduate or upper-level undergraduate chemistry students is described. Compared with a traditional lecture format, assigning small groups of students to examine literature case studies encourages more active engagement with the course material and…

  11. Isolation of a small molecule with anti-MRSA activity from a mangrove symbiont Streptomyces sp. PVRK-1 and its biomedical studies inZebrafish embryos

    Institute of Scientific and Technical Information of China (English)

    Rajaretinam Rajesh Kannan; Appadurai Muthamil Iniyan; Vincent Samuel Gnana Prakash


    Objective: The aim of the present study was to isolate the anti-MRSA (Methicillin ResistantStaphylococcus aureus ) molecule from the Mangrove symbiont Streptomyces and its biomedical studies in Zebrafish embryos. Methods: MRSA was isolated from the pus samples of Colachal hospitals and confirmed by amplification of mecA gene. Anti-MRSA molecule producing strain was identified by 16s rRNA gene sequencing. Anti-MRSA compound production was optimized by Solid State Fermentation (SSF) and the purification of the active molecule was carried out by TLC and RP-HPLC. The inhibitory concentration and LC50 were calculated using Statistical software SPSS. The Biomedical studies including the cardiac assay and organ toxicity assessment were carried out in Zebrafish. Results: The bioactive anti-MRSA small molecule A2 was purified by TLC with Rf value of 0.37 with 1.389 retention time at RP-HPLC. The Inhibitory Concentration of the purified molecule A2 was 30 μg/mL but, the inhibitory concentration of the MRSA in the infected embryo was 32-34 μg/mL for TLC purified molecule A2 with LC50 mean value was 61.504 μg/mL. Zebrafish toxicity was assessed in 48-60 μg/mL by observing the physiological deformities and the heart beat rates (HBR) of embryos for anti MRSA molecule showed the mean of 41.33-41.67 HBR/15 seconds for 40 μg/mL and control was 42.33-42.67 for 15 seconds which significantly showed that the anti-MRSA molecule A2 did not affected the HBR. Conclusions:Anti-MRSA molecule from Streptomyces sp PVRK-1 was isolated and biomedical studies in Zebrafish model assessed that the molecule was non toxic at the minimal inhibitory concentration of MRSA.

  12. Plant-derived flavone Apigenin: The small-molecule with promising activity against therapeutically resistant prostate cancer. (United States)

    Ganai, Shabir Ahmad


    Prostate cancer is the second leading cause of cancer related deaths in men in the United States. Mounting evidences suggest that in the pathophysiology of prostate cancer epigenetic modifications play a considerable role. Histone deacetylases (HDACs) have strong crosstalk with prostate cancer progression as they regulate various genes meant for tumour suppression. HDACs are emerging as striking molecular targets for anticancer drugs and therapy as their aberrant expression has been implicated in several cancers. Histone deacetylase inhibitors (HDACi), the small molecules interfering HDACs are the propitious chemotherapeutic agents as they tune the altered acetylation homeostasis for attenuating disease signalling. More than 20 HDACi have entered into the clinical trials and 4 have crossed the journey by gaining FDA approval for treating distinct haematological malignancies including multiple myeloma. Despite the therapeutic benefits, the synthetic HDACi cause detrimental side effects like atrial fibrillation, raising concerns regarding their applicability. Taking these facts into consideration the current article focused on plant-derived HDAC inhibitor Apigenin and its marvelous role in prostate cancer therapy. Moreover, the article sheds light on Apigenin induced apoptosis in various prostate cancer models. The defined inhibitor provokes apoptotic signaling in these models by multiple mechanisms like restraining HDACs, declining the levels of antiapoptotic proteins. Importantly, Apigenin hampers NF-κB signalling and down-modulates its regulated gene products for bringing therapeutic effect. Furthermore, Apigenin shows synergistic effect in combinatorial therapy and induces apoptosis even in prostate cancer models resistant to conventional therapeutic regimens.

  13. Chemokines: Small Molecules Participate in Diabetes

    Directory of Open Access Journals (Sweden)

    S. Mostafa Hosseini-Zijoud


    Full Text Available Background: Chemokines are small protein molecules involved in cell signaling processes. They play a crucial role in many physiological and pathological processes. Chemokines are functionally classified into two categories; inflammatory/inducible and constitutive. Their biologic functional differences are the result of their receptors structural differences. Recently some studies were performed about the chemokines changes in diabetes. Inflammatory mechanisms have an important role in diabetes.Materials and Methods: In this review article we searched the keywords chemokines, diabetes, diabetes pathogenesis, and type 1 and 2 diabetes in Persian resources, PubMed and famous English-language websites through advanced search engines and found the newest studies about the role of chemokines in the pathogenesis of diabetes.Results: The results of the studies showed that diabetes and its disorders enhance the activation of immune cells and the expression of cytokines such as IL-1, IL-6, IL-8, IL-10, SDF-1, INF-γ, TGF-β, MCP-1, IP-10, TNF-α, and RANTES; most of them have impact on the pathogenesis of diabetes.Conclusion: Comparison and analysis of the results obtained from our research and the results of performed studies in the world and Iran shows that chemokines, like other protein molecules involved in the pathogenesis and etiology of diabetes, play a role in this process.

  14. A Novel Small Molecule, LLL12, Inhibits STAT3 Phosphorylation and Activities and Exhibits Potent Growth-Suppressive Activity in Human Cancer Cells

    Directory of Open Access Journals (Sweden)

    Li Lin


    Full Text Available Constitutive activation of signal transducer and activator of transcription 3 (STAT3 signaling is frequently detected in cancer, promoting its emergence as a promising target for cancer treatment. Inhibiting constitutive STAT3 signaling represents a potential therapeutic approach. We used structure-based design to develop a nonpeptide, cell-permeable, small molecule, termed as LLL12, which targets STAT3. LLL12 was found to inhibit STAT3 phosphorylation (tyrosine 705 and induce apoptosis as indicated by the increases of cleaved caspase-3 and poly (ADP-ribose polymerase in various breast, pancreatic, and glioblastoma cancer cell lines expressing elevated levels of STAT3 phosphorylation. LLL12 could also inhibit STAT3 phosphorylation induced by interleukin-6 in MDA-MB-453 breast cancer cells. The inhibition of STAT3 by LLL12 was confirmed by the inhibition of STAT3 DNA binding activity and STAT3-dependent transcriptional luciferase activity. Downstream targets of STAT3, cyclin D1, Bcl-2, and survivin were also downregulated by LLL12 at both protein and messenger RNA levels. LLL12 is a potent inhibitor of cell viability, with half-maximal inhibitory concentrations values ranging between 0.16 and 3.09 µM, which are lower than the reported JAK2 inhibitor WP1066 and STAT3 inhibitor S3I-201 in six cancer cell lines expressing elevated levels of STAT3 phosphorylation. In addition, LLL12 inhibits colony formation and cell migration and works synergistically with doxorubicin and gemcitabine. Furthermore, LLL12 demonstrated a potent inhibitory activity on breast and glioblastoma tumor growth in a mouse xenograft model. Our results indicate that LLL12 may be a potential therapeutic agent for human cancer cells expressing constitutive STAT3 signaling.

  15. Compound 13, an α1-selective small molecule activator of AMPK, inhibits Helicobacter pylori-induced oxidative stresses and gastric epithelial cell apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Hangyong; Zhu, Huanghuang; Lin, Zhou; Lin, Gang; Lv, Guoqiang, E-mail:


    Half of the world's population experiences Helicobacter pylori (H. pylori) infection, which is a main cause of gastritis, duodenal and gastric ulcer, and gastric cancers. In the current study, we investigated the potential role of compound 13 (C13), a novel α1-selective small molecule activator of AMP-activated protein kinase (AMPK), against H. pylori-induced cytotoxicity in cultured gastric epithelial cells (GECs). We found that C13 induced significant AMPK activation, evidenced by phosphorylation of AMPKα1 and ACC (acetyl-CoA carboxylase), in both primary and transformed GECs. Treatment of C13 inhibited H. pylori-induced GEC apoptosis. AMPK activation was required for C13-mediated GEC protection. Inhibition of AMPK kinase activity by the AMPK inhibitor Compound C, or silencing AMPKα1 expression by targeted-shRNAs, alleviated C13-induced GEC protective activities against H. pylori. Significantly, C13 inhibited H. pylori-induced reactive oxygen species (ROS) production in GECs. C13 induced AMPK-dependent expression of anti-oxidant gene heme oxygenase (HO-1) in GECs. Zinc protoporphyrin (ZnPP) and tin protoporphyrin (SnPP), two HO-1 inhibitors, not only suppressed C13-mediated ROS scavenging activity, but also alleviated its activity in GECs against H. pylori. Together, these results indicate that C13 inhibits H. pylori-induced ROS production and GEC apoptosis through activating AMPK–HO–1 signaling. - Highlights: • We synthesized compound 13 (C13), a α1-selective small molecule AMPK activator. • C13-induced AMPK activation requires α1 subunit in gastric epithelial cells (GECs). • C13 enhances Helicobacter pylori-induced pro-survival AMPK activation to inhibit GEC apoptosis. • C13 inhibits H. pylori-induced reactive oxygen species (ROS) production in GECs. • AMPK-heme oxygenase (HO-1) activation is required for C13-mediated anti-oxidant activity.

  16. Modulation of p53's transcriptional function by small molecules



    p53 tumour suppressor is a transcriptional factor which induces apoptosis or growth arrest in response to stress thus eliminating damaged cells. p53 function is frequently abrogated in tumours either via inactivation mutations in the TP53 gene or by elevated activity of p53 negative regulators HDM2 and HDMX. Therefore application of small molecules that reactivate p53 function is a promising strategy for anti-cancer therapy. In addition, small molecules can serve as valuable research tool to ...

  17. Small Organic Molecules for Direct Aldol Reaction

    Institute of Scientific and Technical Information of China (English)

    TANG Zhuo; GONG Liu-Zhu; MI Ai-Qiao; JIANG Yao-Zhong


    Since the pioneering finding by List and Barbas Ⅲ and their coworkers that L-proline could work as a catalyst in the intermolecular direct aldol reaction, the concept of small organic molecules as catalysts has received great attention. However, new organic molecule which have better catalysis ability are reported scarcely.Our groups1 found L-Prolinamides 1 to be active catalysts for the direct aldol reaction of 4-nitrobenaldehyde with neat acetone at room temperature. The enantioselectivity increases as the amide N-H becomes more acidic and thus a better hydrogen bond donor. Introducing another proton donor, hydroxyl, in the catalyst lead to a further improvement in the catalytic enantioselectivity.The calculations reveal that the amide N-H and the terminal hydroxyl groups form hydrogen bonds with the benzaldehyde substrate. These hydrogen bonds reduce the activation energy and cause high enantioselectivity.Catalyst 2, prepared from L-proline and (1S, 2S)-diphenyl-2-aminoethanol, exhibits high enantioselectivities of up to 93% ee for aromatic aldehydes and up to >99% ee for aliphatic aldehydes. It is noteworthy that our results refuted the conventional wisdom that the carboxylic acid group of proline is a reqirement for high enatioselectivity and provide a powerful strategy in the molecular design of new organic catalyst because plentiful chiral resource containing multi-hydrogen bonding donor, for example, peptides.Very recently, we found that L-proline-based peptides 3-7 can catalyze the aldol reactions of hydroxyacetone with aldehydes 8 in aqueous media, to give 1,4-diols 9, the disfavored products with either aldolase or L-proline. Both peptides 5 and 6 give good results.The abilities of peptides 5 and 6 to catalyze the direct aldol reactions of hydroxyacetone with avariety of aldehydes were examined under optimal conditions. The results are shown in table. Highyields and entioselectivities of up to 96% ee were observed for aromatic aldehydes

  18. Application of a small molecule radiopharmaceutical concept to improve kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jae Min [Dept. of Nuclear Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of)


    Recently, large molecules or nanoparticles are actively studied as radiopharmaceuticals. However, their kinetics is problematic because of a slow penetration through the capillaries and slow distribution to the target. To improve the kinetics, a two-step targeting method can be applied by using small molecules and very rapid copper-free click reaction. Although this method might have limitations such as internalization of the first targeted conjugate, it will provide high target-to-non-target ratio imaging of radiopharmaceuticals. The majority of radiopharmaceuticals belong to small molecules of which the molecular weight is less than 2000 Da, and the molecular size is smaller than 2 nm generally. The outstanding feature of the small molecule radiopharmaceuticals compared to large molecules is with their kinetics. Their distribution to target and clearance from non-target tissues are very rapid, which is the essential requirement of radiopharmaceuticals. In conclusion, the small molecule radiopharmaceuticals generally show excellent biodistribution properties; however, they show poor efficiency of radioisotope delivery. Large molecule or nanoparticle radiopharmaceuticals have advantages of multimodal and efficient delivery, but lower target-to-non-target ratio. Two-step targeting using a bio-orthogonal copper-free click reaction can be a solution of the problem of large molecule or nanoparticle radiopharmaceuticals. The majority of radiopharmaceuticals belong to small molecules of which the molecular weight is less than 2000 Da, and the molecular size is smaller than 2 nm generally. The outstanding feature of the small molecule radiopharmaceuticals compared to large molecules is with their kinetics. Their distribution to target and clearance from non-target tissues are very rapid, which is the essential requirement of radiopharmaceuticals.

  19. Database of Small Molecule Thermochemistry for Combustion

    KAUST Repository

    Goldsmith, C. Franklin


    High-accuracy ab initio thermochemistry is presented for 219 small molecules relevant in combustion chemistry, including many radical, biradical, and triplet species. These values are critical for accurate kinetic modeling. The RQCISD(T)/cc-PV∞QZ//B3LYP/6-311++G(d,p) method was used to compute the electronic energies. A bond additivity correction for this method has been developed to remove systematic errors in the enthalpy calculations, using the Active Thermochemical Tables as reference values. On the basis of comparison with the benchmark data, the 3σ uncertainty in the standard-state heat of formation is 0.9 kcal/mol, or within chemical accuracy. An uncertainty analysis is presented for the entropy and heat capacity. In many cases, the present values are the most accurate and comprehensive numbers available. The present work is compared to several published databases. In some cases, there are large discrepancies and errors in published databases; the present work helps to resolve these problems. © 2012 American Chemical Society.

  20. Defining RNA–Small Molecule Affinity Landscapes Enables Design of a Small Molecule Inhibitor of an Oncogenic Noncoding RNA (United States)


    RNA drug targets are pervasive in cells, but methods to design small molecules that target them are sparse. Herein, we report a general approach to score the affinity and selectivity of RNA motif–small molecule interactions identified via selection. Named High Throughput Structure–Activity Relationships Through Sequencing (HiT-StARTS), HiT-StARTS is statistical in nature and compares input nucleic acid sequences to selected library members that bind a ligand via high throughput sequencing. The approach allowed facile definition of the fitness landscape of hundreds of thousands of RNA motif–small molecule binding partners. These results were mined against folded RNAs in the human transcriptome and identified an avid interaction between a small molecule and the Dicer nuclease-processing site in the oncogenic microRNA (miR)-18a hairpin precursor, which is a member of the miR-17-92 cluster. Application of the small molecule, Targapremir-18a, to prostate cancer cells inhibited production of miR-18a from the cluster, de-repressed serine/threonine protein kinase 4 protein (STK4), and triggered apoptosis. Profiling the cellular targets of Targapremir-18a via Chemical Cross-Linking and Isolation by Pull Down (Chem-CLIP), a covalent small molecule–RNA cellular profiling approach, and other studies showed specific binding of the compound to the miR-18a precursor, revealing broadly applicable factors that govern small molecule drugging of noncoding RNAs.

  1. Small-molecule control of protein function through Staudinger reduction (United States)

    Luo, Ji; Liu, Qingyang; Morihiro, Kunihiko; Deiters, Alexander


    Using small molecules to control the function of proteins in live cells with complete specificity is highly desirable, but challenging. Here we report a small-molecule switch that can be used to control protein activity. The approach uses a phosphine-mediated Staudinger reduction to activate protein function. Genetic encoding of an ortho-azidobenzyloxycarbonyl amino acid using a pyrrolysyl transfer RNA synthetase/tRNACUA pair in mammalian cells enables the site-specific introduction of a small-molecule-removable protecting group into the protein of interest. Strategic placement of this group renders the protein inactive until deprotection through a bioorthogonal Staudinger reduction delivers the active wild-type protein. This developed methodology was applied to the conditional control of several cellular processes, including bioluminescence (luciferase), fluorescence (enhanced green fluorescent protein), protein translocation (nuclear localization sequence), DNA recombination (Cre) and gene editing (Cas9).

  2. The Role of Sulfhydryl Reactivity of Small Molecules for the Activation of the KEAP1/NRF2 Pathway and the Heat Shock Response

    Directory of Open Access Journals (Sweden)

    Albena T. Dinkova-Kostova


    Full Text Available The KEAP1/NRF2 pathway and the heat shock response are two essential cytoprotective mechanisms that allow adaptation and survival under conditions of oxidative, electrophilic, and thermal stress by regulating the expression of elaborate networks of genes with versatile protective functions. The two pathways are independently regulated by the transcription factor nuclear factor-erythroid 2 p45-related factor 2 (NRF2 and heat shock factor 1 (HSF1, respectively. The activity of these transcriptional master regulators increases during conditions of stress and also upon encounter of small molecules (inducers, both naturally occurring as well as synthetically produced. Inducers have a common chemical property: the ability to react with sulfhydryl groups. The protein targets of such sulfhydryl-reactive compounds are equipped with highly reactive cysteine residues, which serve as sensors for inducers. The initial cysteine-sensed signal is further relayed to affect the expression of large networks of genes, which in turn can ultimately influence complex cell fate decisions such as life and death. The paper summarizes the multiple lines of experimental evidence demonstrating that the reactivity with sulfhydryl groups is a major determinant of the mechanism of action of small molecule dual activators of the KEAP1/NRF2 pathway and the heat shock response.

  3. Small molecule-guided thermoresponsive supramolecular assemblies

    KAUST Repository

    Rancatore, Benjamin J.


    Small organic molecules with strong intermolecular interactions have a wide range of desirable optical and electronic properties and rich phase behaviors. Incorporating them into block copolymer (BCP)-based supramolecules opens new routes to generate functional responsive materials. Using oligothiophene- containing supramolecules, we present systematic studies of critical thermodynamic parameters and kinetic pathway that govern the coassemblies of BCP and strongly interacting small molecules. A number of potentially useful morphologies for optoelectronic materials, including a nanoscopic network of oligothiophene and nanoscopic crystalline lamellae, were obtained by varying the assembly pathway. Hierarchical coassemblies of oligothiophene and BCP, rather than macrophase separation, can be obtained. Crystallization of the oligothiophene not only induces chain stretching of the BCP block the oligothiophene is hydrogen bonded to but also changes the conformation of the other BCP coil block. This leads to an over 70% change in the BCP periodicity (e.g., from 31 to 53 nm) as the oligothiophene changes from a melt to a crystalline state, which provides access to a large BCP periodicity using fairly low molecular weight BCP. The present studies have demonstrated the experimental feasibility of generating thermoresponsive materials that convert heat into mechanical energy. Incorporating strongly interacting small molecules into BCP supramolecules effectively increases the BCP periodicity and may also open new opportunities to tailor their optical properties without the need for high molecular weight BCP. © 2012 American Chemical Society.

  4. Small molecule screening identifies targetable zebrafish pigmentation pathways

    DEFF Research Database (Denmark)

    Colanesi, Sarah; Taylor, Kerrie L; Temperley, Nicholas D


    Small molecules complement genetic mutants and can be used to probe pigment cell biology by inhibiting specific proteins or pathways. Here, we present the results of a screen of active compounds for those that affect the processes of melanocyte and iridophore development in zebrafish and investig......Small molecules complement genetic mutants and can be used to probe pigment cell biology by inhibiting specific proteins or pathways. Here, we present the results of a screen of active compounds for those that affect the processes of melanocyte and iridophore development in zebrafish...

  5. Small molecules CK-666 and CK-869 inhibit actin-related protein 2/3 complex by blocking an activating conformational change. (United States)

    Hetrick, Byron; Han, Min Suk; Helgeson, Luke A; Nolen, Brad J


    Actin-related protein 2/3 (Arp2/3) complex is a seven-subunit assembly that nucleates branched actin filaments. Small molecule inhibitors CK-666 and CK-869 bind to Arp2/3 complex and inhibit nucleation, but their modes of action are unknown. Here, we use biochemical and structural methods to determine the mechanism of each inhibitor. Our data indicate that CK-666 stabilizes the inactive state of the complex, blocking movement of the Arp2 and Arp3 subunits into the activated filament-like (short pitch) conformation, while CK-869 binds to a serendipitous pocket on Arp3 and allosterically destabilizes the short pitch Arp3-Arp2 interface. These results provide key insights into the relationship between conformation and activity in Arp2/3 complex and will be critical for interpreting the influence of the inhibitors on actin filament networks in vivo.

  6. Benzimidazole derivative small-molecule 991 enhances AMPK activity and glucose uptake induced by AICAR or contraction in skeletal muscle

    DEFF Research Database (Denmark)

    Bultot, Laurent; Jensen, Thomas Elbenhardt; Lai, Yu-Chiang


    be beneficial for both purposes. Here, we investigated if a recently described potent AMPK activator called 991, in combination with the commonly used activator 5-aminoimidazole-4-carboxamide riboside or contraction, further enhances AMPK activity and glucose transport in mouse skeletal muscle ex vivo. Given...... that the γ3-subunit is exclusively expressed in skeletal muscle and has been implicated in contraction-induced glucose transport, we measured the activity of AMPKγ3 as well as ubiquitously expressed γ1-containing complexes. We initially validated the specificity of the antibodies for the assessment...... profoundly enhanced AMPKγ1/γ3 complex activation and glucose transport compared with any of the single treatments. The study demonstrates the utility of a dual activator approach to achieve a greater activation of AMPK and downstream physiological responses in various cell types, including skeletal muscle....

  7. Evaluating enzymatic synthesis of small molecule drugs. (United States)

    Moura, Matthew; Finkle, Justin; Stainbrook, Sarah; Greene, Jennifer; Broadbelt, Linda J; Tyo, Keith E J


    There have been many achievements in applying biochemical synthetic routes to the synthesis of commodity chemicals. However, most of these endeavors have focused on optimizing and increasing the yields of naturally existing pathways. We sought to evaluate the potential for biosynthesis beyond the limits of known biochemistry towards the production of small molecule drugs that do not exist in nature. Because of the potential for improved yields compared to total synthesis, and therefore lower manufacturing costs, we focused on drugs for diseases endemic to many resource poor regions, like tuberculosis and HIV. Using generalized biochemical reaction rules, we were able to design biochemical pathways for the production of eight small molecule drugs or drug precursors and identify potential enzyme-substrate pairs for nearly every predicted reaction. All pathways begin from native metabolites, abrogating the need for specialized precursors. The simulated pathways showed several trends with the sequential ordering of reactions as well as the types of chemistries used. For some compounds, the main obstacles to finding feasible biochemical pathways were the lack of appropriate, natural starting compounds and a low diversity of biochemical coupling reactions necessary to synthesize molecules with larger molecular size.

  8. Identification and Small Molecule Inhibition of an Activating Transcription Factor 4 (ATF4)-dependent Pathway to Age-related Skeletal Muscle Weakness and Atrophy* (United States)

    Ebert, Scott M.; Dyle, Michael C.; Bullard, Steven A.; Dierdorff, Jason M.; Murry, Daryl J.; Fox, Daniel K.; Bongers, Kale S.; Lira, Vitor A.; Meyerholz, David K.; Talley, John J.; Adams, Christopher M.


    Aging reduces skeletal muscle mass and strength, but the underlying molecular mechanisms remain elusive. Here, we used mouse models to investigate molecular mechanisms of age-related skeletal muscle weakness and atrophy as well as new potential interventions for these conditions. We identified two small molecules that significantly reduce age-related deficits in skeletal muscle strength, quality, and mass: ursolic acid (a pentacyclic triterpenoid found in apples) and tomatidine (a steroidal alkaloid derived from green tomatoes). Because small molecule inhibitors can sometimes provide mechanistic insight into disease processes, we used ursolic acid and tomatidine to investigate the pathogenesis of age-related muscle weakness and atrophy. We found that ursolic acid and tomatidine generate hundreds of small positive and negative changes in mRNA levels in aged skeletal muscle, and the mRNA expression signatures of the two compounds are remarkably similar. Interestingly, a subset of the mRNAs repressed by ursolic acid and tomatidine in aged muscle are positively regulated by activating transcription factor 4 (ATF4). Based on this finding, we investigated ATF4 as a potential mediator of age-related muscle weakness and atrophy. We found that a targeted reduction in skeletal muscle ATF4 expression reduces age-related deficits in skeletal muscle strength, quality, and mass, similar to ursolic acid and tomatidine. These results elucidate ATF4 as a critical mediator of age-related muscle weakness and atrophy. In addition, these results identify ursolic acid and tomatidine as potential agents and/or lead compounds for reducing ATF4 activity, weakness, and atrophy in aged skeletal muscle. PMID:26338703

  9. Scorpionate-type coordination in MFU-4l metal-organic frameworks: small-molecule binding and activation upon the thermally activated formation of open metal sites. (United States)

    Denysenko, Dmytro; Grzywa, Maciej; Jelic, Jelena; Reuter, Karsten; Volkmer, Dirk


    Postsynthetic metal and ligand exchange is a versatile approach towards functionalized MFU-4l frameworks. Upon thermal treatment of MFU-4l formates, coordinatively strongly unsaturated metal centers, such as zinc(II) hydride or copper(I) species, are generated selectively. Cu(I)-MFU-4l prepared in this way was stable under ambient conditions and showed fully reversible chemisorption of small molecules, such as O2, N2, and H2, with corresponding isosteric heats of adsorption of 53, 42, and 32 kJ mol(-1), respectively, as determined by gas-sorption measurements and confirmed by DFT calculations. Moreover, Cu(I)-MFU-4l formed stable complexes with C2H4 and CO. These complexes were characterized by FTIR spectroscopy. The demonstrated hydride transfer to electrophiles and strong binding of small gas molecules suggests these novel, yet robust, metal-organic frameworks with open metal sites as promising catalytic materials comprising earth-abundant metal elements.

  10. Synthesis and characterization of perm-selective SERS-active silica-coated gold nanospheres for the direct detection of small molecules (United States)

    Pierre-Bolivar, Marie Carmelle Serviane

    Noble metal nanomaterials have numerous uses in plasmonic and surface enhanced Raman scattering (SERS) detection applications; however, upon the addition of analytes, nanomaterials often undergo uncontrolled aggregation which leads to inconsistent signal intensities. To overcome this limitation, the effect of gold nanosphere concentration, column purification, and surface chemistry functionalization using internally etched silica stabilization methods was investigated on SERS assays for small molecule detection. Nanostructure composition, size, shape, stability, surface chemistry, optical properties, and SERS-activity were monitored using localized surface plasmon resonance (LSPR or extinction) spectroscopy, transmission electron microscopy (TEM), and Raman spectroscopy. First, the behavior of citrate-stabilized gold nanospheres was monitored as a function of molecular surface coverage. Both extinction and SERS spectral intensities increased linearly below monolayer functionalization. Above this value, however, uncontrolled nanoparticle aggregation occurred and large but irreproducible SERS signal intensities were monitored. Next, gold nanoparticles were encapsulated with varying silica shell thicknesses and purified using traditional centrifugation steps and/or column chromatography. Relative to the traditionally purified (i.e. centrifuged) samples, the SERS responses from small molecules using the column purified nanoparticle samples followed a well-known SERS distance-dependence model. Thus, surface chemistry cannot form more than a 2 nm thick layer on gold nanospheres if SERS applications were targeted. To overcome these challenges, gold nanospheres encapsulated with a thick silica shell were made SERS-active by etching the internal silica layer near the metal surface. During the synthesis of these internally etched silica-coated gold nanospheres, the LSPR wavelength shift, a parameter related to the effective local refractive index near the gold core, was

  11. Neohesperidin dihydrochalcone: presentation of a small molecule activator of mammalian alpha-amylase as an allosteric effector. (United States)

    Kashani-Amin, Elaheh; Larijani, Bagher; Ebrahim-Habibi, Azadeh


    Flavonoids and their precursor trans-chalcone have been reported as inhibitors of mammalian alpha-amylase. With regard to this background, neohesperidin dihydrochalcone (NHDC) effect was investigated toward porcine pancreatic alpha-amylase (PPA), and found to be an activator of the enzyme. The maximal activation (up to threefold) was found to occur at 4.8mM of NHDC, which could be considered to have a high activation profile, with regard to the alpha and beta parameters (alpha<1activator of the enzyme and based on the results obtained from modeling tools, it is suggested to interact with PPA at a hydrophilic site located at the N-terminal, far from the active site of the enzyme.

  12. Small azomethine molecules and their use in photovoltaic devices

    NARCIS (Netherlands)

    Dingemans, T.J.; Petrus, M.L.


    The present invention is in the field of a small azomethine molecule having photovoltaic characteristics, a method of synthesizing said molecule, use of said molecule in a photovoltaic device, a solar cell comprising said molecule, and a film comprising said molecule. The present molecules may find

  13. Increased Hydrogel Swelling Induced by Absorption of Small Molecules. (United States)

    Nam, Changwoo; Zimudzi, Tawanda J; Geise, Geoffrey M; Hickner, Michael A


    The water and small molecule uptake behavior of amphiphilic diacrylate terminated poly(dimethylsiloxane) (PDMSDA)/poly(ethylene glycol diacrylate) (PEGDA) cross-linked hydrogels were studied using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. These hydrogel networks absorbed more water as the PEGDA content of the network increased. In contrast to typical osmotic deswelling behavior that occurs when liquid water equilibrated hydrogels are immersed in small molecule solutions with water activities less than unity, water-swollen gels immersed in 2-acrylamido-2-methylpropanesulfonic acid (AMPS-H) solutions rapidly regained their water content within 4 min following an initial deswelling response. In situ ATR-FTIR analysis of the hydrogel film during the dynamic swelling experiment indicated that small molecule absorption into the gel played an important role in inducing gel reswelling in low water activity solutions. This aspect of polymer gel water uptake and interaction with small molecules is important for optimizing hydrogel coatings and hydrophilic polymer applications where there is an interaction between the internal chemical structure of the gel and electrolytes or other molecules in solution.

  14. Implementation of a high-throughput screen for identifying small molecules to activate the Keap1-Nrf2-ARE pathway.

    Directory of Open Access Journals (Sweden)

    Kai Connie Wu

    Full Text Available Nuclear factor erythroid 2-related factor 2 (Nrf2 is a transcription factor that induces a battery of cytoprotective genes involved in antioxidant defense through binding to Antioxidant Response Elements (ARE located in the promoter regions of these genes. To identify Nrf2 activators for the treatment of oxidative/electrophilic stress-induced diseases, the present study developed a high-throughput assay to evaluate Nrf2 activation using AREc32 cells that contain a luciferase gene under the control of ARE promoters. Of the 47,000 compounds screened, 238 (top 0.5% hits of the chemicals increased the luminescent signal more than 14.4-fold and were re-tested at eleven concentrations in a range of 0.01-30 µM. Of these 238 compounds, 231 (96% increased the luminescence signal in a concentration-dependent manner. Chemical structure relationship analysis of these 231 compounds indicated enrichment of four chemical scaffolds (diaryl amides and diaryl ureas, oxazoles and thiazoles, pyranones and thiapyranones, and pyridinones and pyridazinones. In addition, 30 of these 231 compounds were highly effective and/or potent in activating Nrf2, with a greater than 80-fold increase in luminescence, or an EC50 lower than 1.6 µM. These top 30 compounds were also screened in Hepa1c1c7 cells for an increase in Nqo1 mRNA, the prototypical Nrf2-target gene. Of these 30 compounds, 17 increased Nqo1 mRNA in a concentration-dependent manner. In conclusion, the present study documents the development, implementation, and validation of a high-throughput screen to identify activators of the Keap1-Nrf2-ARE pathway. Results from this screening identified Nrf2 activators, and provide novel insights into chemical scaffolds that might prevent oxidative/electrophilic stress-induced toxicity and carcinogenesis.

  15. Small Molecule Library Synthesis Using Segmented Flow

    Directory of Open Access Journals (Sweden)

    Christina M. Thompson


    Full Text Available Flow chemistry has gained considerable recognition as a simple, efficient, and safe technology for the synthesis of many types of organic and inorganic molecules ranging in scope from large complex natural products to silicon nanoparticles. In this paper we describe a method that adapts flow chemistry to the synthesis of libraries of compounds using a fluorous immiscible solvent as a spacer between reactions. The methodology was validated in the synthesis of two small heterocycle containing libraries. The reactions were performed on a 0.2 mmol scale, enabling tens of milligrams of material to be generated in a single 200 mL reaction plug. The methodology allowed library synthesis in half the time of conventional microwave synthesis while maintaining similar yields. The ability to perform multiple, potentially unrelated reactions in a single run is ideal for making small quantities of many different compounds quickly and efficiently.

  16. Physiological roles of small RNA molecules. (United States)

    Michaux, Charlotte; Verneuil, Nicolas; Hartke, Axel; Giard, Jean-Christophe


    Unlike proteins, RNA molecules have emerged lately as key players in regulation in bacteria. Most reviews hitherto focused on the experimental and/or in silico methods used to identify genes encoding small RNAs (sRNAs) or on the diverse mechanisms of these RNA regulators to modulate expression of their targets. However, less is known about their biological functions and their implications in various physiological responses. This review aims to compile what is known presently about the diverse roles of sRNA transcripts in the regulation of metabolic processes, in different growth conditions, in adaptation to stress and in microbial pathogenesis. Several recent studies revealed that sRNA molecules are implicated in carbon metabolism and transport, amino acid metabolism or metal sensing. Moreover, regulatory RNAs participate in cellular adaptation to environmental changes, e.g. through quorum sensing systems or development of biofilms, and analyses of several sRNAs under various physiological stresses and culture conditions have already been performed. In addition, recent experiments performed with Gram-positive and Gram-negative pathogens showed that regulatory RNAs play important roles in microbial virulence and during infection. The combined results show the diversity of regulation mechanisms and physiological processes in which sRNA molecules are key actors.

  17. Enzyme kinetics and distinct modulation of the protein kinase N family of kinases by lipid activators and small molecule inhibitors


    Falk, Matthew D.; Liu, Wei; Bolaños, Ben; Unsal-Kacmaz, Keziban; Klippel, Anke; Grant, Stephan; Brooun, Alexei; Timofeevski, Sergei


    The PKN (protein kinase N) family of Ser/Thr protein kinases regulates a diverse set of cellular functions, such as cell migration and cytoskeletal organization. Inhibition of tumour PKN activity has been explored as an oncology therapeutic approach, with a PKN3-targeted RNAi (RNA interference)-derived therapeutic agent in Phase I clinical trials. To better understand this important family of kinases, we performed detailed enzymatic characterization, determining the kinetic mechanism and lipi...

  18. New Perspectives on Specific Immune-Depletion Technique Using Monoclonal Antibodies against Small Active Molecules in Herbs



    One of the main focuses in Chinese Medicine research is the identification of efficacious components in Chinese herbal medicine (CHM). Studies in such area are difficult due to the complexity and the synergistic characteristics of CHM. Current methods to track and separate active components are not adequate to meet the needs of revealing effects and identify substances and pharmacological mechanisms, which directly restrict the modernization and globalization of CHM. In this paper, a new meth...

  19. Small molecule binding sites on the Ras:SOS complex can be exploited for inhibition of Ras activation. (United States)

    Winter, Jon J G; Anderson, Malcolm; Blades, Kevin; Brassington, Claire; Breeze, Alexander L; Chresta, Christine; Embrey, Kevin; Fairley, Gary; Faulder, Paul; Finlay, M Raymond V; Kettle, Jason G; Nowak, Thorsten; Overman, Ross; Patel, S Joe; Perkins, Paula; Spadola, Loredana; Tart, Jonathan; Tucker, Julie A; Wrigley, Gail


    Constitutively active mutant KRas displays a reduced rate of GTP hydrolysis via both intrinsic and GTPase-activating protein-catalyzed mechanisms, resulting in the perpetual activation of Ras pathways. We describe a fragment screening campaign using X-ray crystallography that led to the discovery of three fragment binding sites on the Ras:SOS complex. The identification of tool compounds binding at each of these sites allowed exploration of two new approaches to Ras pathway inhibition by stabilizing or covalently modifying the Ras:SOS complex to prevent the reloading of Ras with GTP. Initially, we identified ligands that bound reversibly to the Ras:SOS complex in two distinct sites, but these compounds were not sufficiently potent inhibitors to validate our stabilization hypothesis. We conclude by demonstrating that covalent modification of Cys118 on Ras leads to a novel mechanism of inhibition of the SOS-mediated interaction between Ras and Raf and is effective at inhibiting the exchange of labeled GDP in both mutant (G12C and G12V) and wild type Ras.

  20. Small molecule phagocytosis inhibitors for immune cytopenias. (United States)

    Neschadim, Anton; Kotra, Lakshmi P; Branch, Donald R


    Immune cytopenias are conditions characterized by low blood cell counts, such as platelets in immune thrombocytopenia (ITP) and red blood cells in autoimmune hemolytic anemia (AIHA). Chronic ITP affects approximately 4 in 100,000 adults annually while AIHA is much less common. Extravascular phagocytosis and massive destruction of autoantibody-opsonized blood cells by macrophages in the spleen and liver are the hallmark of these conditions. Current treatment modalities for ITP and AIHA include the first-line use of corticosteroids; whereas, IVIg shows efficacy in ITP but not AIHA. One main mechanism of action by which IVIg treatment leads to the reduction in platelet destruction rates in ITP is thought to involve Fcγ receptor (FcγR) blockade, ultimately leading to the inhibition of extravascular platelet phagocytosis. IVIg, which is manufactured from the human plasma of thousands of donors, is a limited resource, and alternative treatments, particularly those based on bioavailable small molecules, are needed. In this review, we overview the pathophysiology of ITP, the role of Fcγ receptors, and the mechanisms of action of IVIg in treating ITP, and outline the efforts and progress towards developing novel, first-in-class inhibitors of phagocytosis as synthetic, small molecule substitutes for IVIg in ITP and other conditions where the pathobiology of the disease involves phagocytosis.

  1. Borreliacidal activity of Borrelia metal transporter A (BmtA binding small molecules by manganese transport inhibition

    Directory of Open Access Journals (Sweden)

    Wagh D


    Full Text Available Dhananjay Wagh,* Venkata Raveendra Pothineni,* Mohammed Inayathullah, Song Liu, Kwang-Min Kim, Jayakumar Rajadas Biomaterials and Advanced Drug Delivery Laboratory, Stanford Cardiovascular Pharmacology Division, Cardiovascular Institute, Stanford University School of Medicine, Palo Alto, CA, USA *These authors contributed equally to this work  Abstract: Borrelia burgdorferi, the causative agent of Lyme disease, utilizes manganese (Mn for its various metabolic needs. We hypothesized that blocking Mn transporter could be a possible approach to inhibit metabolic activity of this pathogen and eliminate the infection. We used a combination of in silico protein structure prediction together with molecular docking to target the Borrelia metal transporter A (BmtA, a single known Mn transporter in Borrelia and screened libraries of FDA approved compounds that could potentially bind to the predicted BmtA structure with high affinity. Tricyclic antihistamines such as loratadine, desloratadine, and 3-hydroxydesloratadine as well as yohimbine and tadalafil demonstrated a tight binding to the in silico folded BmtA transporter. We, then, tested borreliacidal activity and dose response of the shortlisted compounds from this screen using a series of in vitro assays. Amongst the probed compounds, desloratadine exhibited potent borreliacidal activity in vitro at and above 78 µg/mL (250 µM. Borrelia treated with lethal doses of desloratadine exhibited a significant loss of intracellular Mn specifically and a severe structural damage to the bacterial cell wall. Our results support the possibility of developing a novel, targeted therapy to treat Lyme disease by targeting specific metabolic needs of Borrelia.  Keywords: Lyme disease, BmtA, Borrelia burgdorferi, desloratadine, Bac Titer-Glo assay

  2. Exporters for Production of Amino Acids and Other Small Molecules. (United States)

    Eggeling, Lothar


    Microbes are talented catalysts to synthesize valuable small molecules in their cytosol. However, to make full use of their skills - and that of metabolic engineers - the export of intracellularly synthesized molecules to the culture medium has to be considered. This step is as essential as is each step for the synthesis of the favorite molecule of the metabolic engineer, but is frequently not taken into account. To export small molecules via the microbial cell envelope, a range of different types of carrier proteins is recognized to be involved, which are primary active carriers, secondary active carriers, or proteins increasing diffusion. Relevant export may require just one carrier as is the case with L-lysine export by Corynebacterium glutamicum or involve up to four carriers as known for L-cysteine excretion by Escherichia coli. Meanwhile carriers for a number of small molecules of biotechnological interest are recognized, like for production of peptides, nucleosides, diamines, organic acids, or biofuels. In addition to carriers involved in amino acid excretion, such carriers and their impact on product formation are described, as well as the relatedness of export carriers which may serve as a hint to identify further carriers required to improve product formation by engineering export.

  3. Managing missing measurements in small-molecule screens (United States)

    Browning, Michael R.; Calhoun, Bradley T.; Swamidass, S. Joshua.


    In a typical high-throughput screening (HTS) campaign, less than 1 % of the small-molecule library is characterized by confirmatory experiments. As much as 99 % of the library's molecules are set aside—and not included in downstream analysis—although some of these molecules would prove active were they sent for confirmatory testing. These missing experimental measurements prevent active molecules from being identified by screeners. In this study, we propose managing missing measurements using imputation—a powerful technique from the machine learning community—to fill in accurate guesses where measurements are missing. We then use these imputed measurements to construct an imputed visualization of HTS results, based on the scaffold tree visualization from the literature. This imputed visualization identifies almost all groups of active molecules from a HTS, even those that would otherwise be missed. We validate our methodology by simulating HTS experiments using the data from eight quantitative HTS campaigns, and the implications for drug discovery are discussed. In particular, this method can rapidly and economically identify novel active molecules, each of which could have novel function in either binding or selectivity in addition to representing new intellectual property.

  4. Targeting Mycobacterium tuberculosis topoisomerase I by small-molecule inhibitors. (United States)

    Godbole, Adwait Anand; Ahmed, Wareed; Bhat, Rajeshwari Subray; Bradley, Erin K; Ekins, Sean; Nagaraja, Valakunja


    We describe inhibition of Mycobacterium tuberculosis topoisomerase I (MttopoI), an essential mycobacterial enzyme, by two related compounds, imipramine and norclomipramine, of which imipramine is clinically used as an antidepressant. These molecules showed growth inhibition of both Mycobacterium smegmatis and M. tuberculosis cells. The mechanism of action of these two molecules was investigated by analyzing the individual steps of the topoisomerase I (topoI) reaction cycle. The compounds stimulated cleavage, thereby perturbing the cleavage-religation equilibrium. Consequently, these molecules inhibited the growth of the cells overexpressing topoI at a low MIC. Docking of the molecules on the MttopoI model suggested that they bind near the metal binding site of the enzyme. The DNA relaxation activity of the metal binding mutants harboring mutations in the DxDxE motif was differentially affected by the molecules, suggesting that the metal coordinating residues contribute to the interaction of the enzyme with the drug. Taken together, the results highlight the potential of these small molecules, which poison the M. tuberculosis and M. smegmatis topoisomerase I, as leads for the development of improved molecules to combat mycobacterial infections. Moreover, targeting metal coordination in topoisomerases might be a general strategy to develop new lead molecules.

  5. Small Talk: Children's Everyday `Molecule' Ideas (United States)

    Jakab, Cheryl


    This paper reports on 6-11-year-old children's `sayings and doings' (Harré 2002) as they explore molecule artefacts in dialectical-interactive teaching interviews (Fleer, Cultural Studies of Science Education 3:781-786, 2008; Hedegaard et al. 2008). This sociocultural study was designed to explore children's everyday awareness of and meaning-making with cultural molecular artefacts. Our everyday world is populated with an ever increasing range of molecular or nanoworld words, symbols, images, and games. What do children today say about these artefacts that are used to represent molecular world entities? What are the material and social resources that can influence a child's everyday and developing scientific ideas about `molecules'? How do children interact with these cognitive tools when given expert assistance? What meaning-making is afforded when children are socially and materially assisted in using molecular tools in early chemical and nanoworld thinking? Tool-dependent discursive studies show that provision of cultural artefacts can assist and direct developmental thinking across many domains of science (Schoultz et al., Human Development 44:103-118, 2001; Siegal 2008). Young children's use of molecular artefacts as cognitive tools has not received much attention to date (Jakab 2009a, b). This study shows 6-11-year-old children expressing everyday ideas of molecular artefacts and raising their own questions about the artefacts. They are seen beginning to domesticate (Erneling 2010) the words, symbols, and images to their own purposes when given the opportunity to interact with such artefacts in supported activity. Discursive analysis supports the notion that using `molecules' as cultural tools can help young children to begin `putting on molecular spectacles' (Kind 2004). Playing with an interactive game (ICT) is shown to be particularly helpful in assisting children's early meaning-making with representations of molecules, atoms, and their chemical symbols.

  6. Biology-oriented synthesis of a natural-product inspired oxepane collection yields a small-molecule activator of the Wnt-pathway. (United States)

    Basu, Sudipta; Ellinger, Bernhard; Rizzo, Stefano; Deraeve, Céline; Schürmann, Markus; Preut, Hans; Arndt, Hans-Dieter; Waldmann, Herbert


    In Biology Oriented Synthesis the scaffolds of biologically relevant compound classes inspire the synthesis of focused compound collections enriched in bioactivity. This criterion is met by the structurally complex scaffolds of natural products (NPs) selected in evolution. The synthesis of NP-inspired compound collections approaching the complexity of NPs calls for the development of efficient synthetic methods. We have developed a one pot 4-7 step synthesis of mono-, bi-, and tricyclic oxepanes that resemble the core scaffolds of numerous NPs with diverse bioactivities. This sequence entails a ring-closing ene-yne metathesis reaction as key step and makes productive use of polymer-immobilized scavenger reagents. Biological profiling of a corresponding focused compound collection in a reporter gene assay monitoring for Wnt-signaling modulation revealed active Wntepanes. This unique class of small-molecule activators of the Wnt pathway modulates the van-Gogh-like receptor proteins (Vangl), which were previously identified in noncanonical Wnt signaling, and acts in synergy with the canonical activator protein (Wnt-3a).

  7. Modulation of glucokinase by glucose, small-molecule activator and glucokinase regulatory protein: steady-state kinetic and cell-based analysis. (United States)

    Bourbonais, Francis J; Chen, Jing; Huang, Cong; Zhang, Yanwei; Pfefferkorn, Jeffrey A; Landro, James A


    GK (glucokinase) is an enzyme central to glucose metabolism that displays positive co-operativity to substrate glucose. Small-molecule GKAs (GK activators) modulate GK catalytic activity and glucose affinity and are currently being pursued as a treatment for Type 2 diabetes. GK progress curves monitoring product formation are linear up to 1 mM glucose, but biphasic at 5 mM, with the transition from the lower initial velocity to the higher steady-state velocity being described by the rate constant kact. In the presence of a liver-specific GKA (compound A), progress curves at 1 mM glucose are similar to those at 5 mM, reflecting activation of GK by compound A. We show that GKRP (GK regulatory protein) is a slow tight-binding inhibitor of GK. Analysis of progress curves indicate that this inhibition is time dependent, with apparent initial and final Ki values being 113 and 12.8 nM respectively. When GK is pre-incubated with glucose and compound A, the inhibition observed by GKRP is time dependent, but independent of GKRP concentration, reflecting the GKA-controlled transition between closed and open GK conformations. These data are supported by cell-based imaging data from primary rat hepatocytes. This work characterizes the modulation of GK by a novel GKA that may enable the design of new and improved GKAs.

  8. A general strategy to construct small molecule biosensors in eukaryotes. (United States)

    Feng, Justin; Jester, Benjamin W; Tinberg, Christine E; Mandell, Daniel J; Antunes, Mauricio S; Chari, Raj; Morey, Kevin J; Rios, Xavier; Medford, June I; Church, George M; Fields, Stanley; Baker, David


    Biosensors for small molecules can be used in applications that range from metabolic engineering to orthogonal control of transcription. Here, we produce biosensors based on a ligand-binding domain (LBD) by using a method that, in principle, can be applied to any target molecule. The LBD is fused to either a fluorescent protein or a transcriptional activator and is destabilized by mutation such that the fusion accumulates only in cells containing the target ligand. We illustrate the power of this method by developing biosensors for digoxin and progesterone. Addition of ligand to yeast, mammalian, or plant cells expressing a biosensor activates transcription with a dynamic range of up to ~100-fold. We use the biosensors to improve the biotransformation of pregnenolone to progesterone in yeast and to regulate CRISPR activity in mammalian cells. This work provides a general methodology to develop biosensors for a broad range of molecules in eukaryotes.

  9. A novel small molecule inhibits STAT3 phosphorylation and DNA binding activity and exhibits potent growth suppressive activity in human cancer cells

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    Lin Li


    Full Text Available Abstract Background Targeting Signal Transducer and Activator of Transcription 3 (STAT3 signaling is an attractive therapeutic approach for most types of human cancers with constitutively activated STAT3. A novel small molecular STAT3 inhibitor, FLLL32 was specifically designed from dietary agent, curcumin to inhibit constitutive STAT3 signaling in multiple myeloma, glioblastoma, liver cancer, and colorectal cancer cells. Results FLLL32 was found to be a potent inhibitor of STAT3 phosphorylation, STAT3 DNA binding activity, and the expression of STAT3 downstream target genes in vitro, leading to the inhibition of cell proliferation as well as the induction of Caspase-3 and PARP cleavages in human multiple myeloma, glioblastoma, liver cancer, and colorectal cancer cell lines. However, FLLL32 exhibited little inhibition on some tyrosine kinases containing SH2 or both SH2 and SH3 domains, and other protein and lipid kinases using a kinase profile assay. FLLL32 was also more potent than four previously reported JAK2 and STAT3 inhibitors as well as curcumin to inhibit cell viability in these cancer cells. Furthermore, FLLL32 selectively inhibited the induction of STAT3 phosphorylation by Interleukin-6 but not STAT1 phosphorylation by IFN-γ. Conclusion Our findings indicate that FLLL32 exhibits potent inhibitory activity to STAT3 and has potential for targeting multiple myeloma, glioblastoma, liver cancer, and colorectal cancer cells expressing constitutive STAT3 signaling.

  10. Plasmin Regulation through Allosteric, Sulfated, Small Molecules

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    Rami A. Al-Horani


    Full Text Available Plasmin, a key serine protease, plays a major role in clot lysis and extracellular matrix remodeling. Heparin, a natural polydisperse sulfated glycosaminoglycan, is known to allosterically modulate plasmin activity. No small allosteric inhibitor of plasmin has been discovered to date. We screened an in-house library of 55 sulfated, small glycosaminoglycan mimetics based on nine distinct scaffolds and varying number and positions of sulfate groups to discover several promising hits. Of these, a pentasulfated flavonoid-quinazolinone dimer 32 was found to be the most potent sulfated small inhibitor of plasmin (IC50 = 45 μM, efficacy = 100%. Michaelis-Menten kinetic studies revealed an allosteric inhibition of plasmin by these inhibitors. Studies also indicated that the most potent inhibitors are selective for plasmin over thrombin and factor Xa, two serine proteases in coagulation cascade. Interestingly, different inhibitors exhibited different levels of efficacy (40%–100%, an observation alluding to the unique advantage offered by an allosteric process. Overall, our work presents the first small, synthetic allosteric plasmin inhibitors for further rational design.

  11. What is next for small-molecule drug discovery? (United States)

    Doweyko, Arthur M; Doweyko, Lidia M


    Humankind has been in the business of discovering drugs for thousands of years. At present, small-molecule drug design is based on specific macromolecular receptors as targets for inhibition or modulation. To this end, a number of clever approaches have evolved over time: computer-aided techniques including structure-activity relationships and synthesis, high-throughput screening, quantitative structure-activity relationships, hypotheses derived from ligand- and/or structure-based information and focused library approaches. In recent years, several alternative strategies have appeared in the form of the emerging paradigms of polypharmacology, systems biology and personalized medicine. These innovations point to key challenges and breakthroughs likely to affect the future of small-molecule drug discovery.

  12. Small molecule inhibition of Epstein-Barr virus nuclear antigen-1 DNA binding activity interferes with replication and persistence of the viral genome. (United States)

    Lee, Eun Kyung; Kim, Sun Young; Noh, Ka-Won; Joo, Eun Hye; Zhao, Bo; Kieff, Elliott; Kang, Myung-Soo


    The replication and persistence of extra chromosomal Epstein-Barr virus (EBV) episome in latently infected cells are primarily dependent on the binding of EBV-encoded nuclear antigen 1 (EBNA1) to the cognate EBV oriP element. In continuation of the previous study, herein we characterized EBNA1 small molecule inhibitors (H20, H31) and their underlying inhibitory mechanisms. In silico docking analyses predicted that H20 fits into a pocket in the EBNA1 DNA binding domain (DBD). However, H20 did not significantly affect EBNA1 binding to its cognate sequence. A limited structure-relationship study of H20 identified a hydrophobic compound H31, as an EBNA1 inhibitor. An in vitro EBNA1 EMSA and in vivo EGFP-EBNA1 confocal microscopy analysis showed that H31 inhibited EBNA1-dependent oriP sequence-specific DNA binding activity, but not sequence-nonspecific chromosomal association. Consistent with this, H31 repressed the EBNA1-dependent transcription, replication, and persistence of an EBV oriP plasmid. Furthermore, H31 induced progressive loss of EBV episome. In addition, H31 selectively retarded the growth of EBV-infected LCL or Burkitt's lymphoma cells. These data indicate that H31 inhibition of EBNA1-dependent DNA binding decreases transcription from and persistence of EBV episome in EBV-infected cells. These new compounds might be useful probes for dissecting EBNA1 functions in vitro and in vivo.

  13. Energy-Related Small Molecule Activation Reactions: Oxygen Reduction and Hydrogen and Oxygen Evolution Reactions Catalyzed by Porphyrin- and Corrole-Based Systems. (United States)

    Zhang, Wei; Lai, Wenzhen; Cao, Rui


    Globally increasing energy demands and environmental concerns related to the use of fossil fuels have stimulated extensive research to identify new energy systems and economies that are sustainable, clean, low cost, and environmentally benign. Hydrogen generation from solar-driven water splitting is a promising strategy to store solar energy in chemical bonds. The subsequent combustion of hydrogen in fuel cells produces electric energy, and the only exhaust is water. These two reactions compose an ideal process to provide clean and sustainable energy. In such a process, a hydrogen evolution reaction (HER), an oxygen evolution reaction (OER) during water splitting, and an oxygen reduction reaction (ORR) as a fuel cell cathodic reaction are key steps that affect the efficiency of the overall energy conversion. Catalysts play key roles in this process by improving the kinetics of these reactions. Porphyrin-based and corrole-based systems are versatile and can efficiently catalyze the ORR, OER, and HER. Because of the significance of energy-related small molecule activation, this review covers recent progress in hydrogen evolution, oxygen evolution, and oxygen reduction reactions catalyzed by porphyrins and corroles.

  14. Electrocatalytic oxidation of small organic molecules in acid medium: enhancement of activity of noble metal nanoparticles and their alloys by supporting or modifying them with metal oxides (United States)

    Kulesza, Pawel J.; Pieta, Izabela S.; Rutkowska, Iwona A.; Wadas, Anna; Marks, Diana; Klak, Karolina; Stobinski, Leszek; Cox, James A.


    Different approaches to enhancement of electrocatalytic activity of noble metal nanoparticles during oxidation of small organic molecules (namely potential fuels for low-temperature fuel cells such as methanol, ethanol and formic acid) are described. A physical approach to the increase of activity of catalytic nanoparticles (e.g. platinum or palladium) involves nanostructuring to obtain highly dispersed systems of high surface area. Recently, the feasibility of enhancing activity of noble metal systems through the formation of bimetallic (e.g. PtRu, PtSn, and PdAu) or even more complex (e.g. PtRuW, PtRuSn) alloys has been demonstrated. In addition to possible changes in the electronic properties of alloys, specific interactions between metals as well as chemical reactivity of the added components have been postulated. We address and emphasize here the possibility of utilization of noble metal and alloyed nanoparticles supported on robust but reactive high surface area metal oxides (e.g. WO3, MoO3, TiO2, ZrO2, V2O5, and CeO2) in oxidative electrocatalysis. This paper concerns the way in which certain inorganic oxides and oxo species can act effectively as supports for noble metal nanoparticles or their alloys during electrocatalytic oxidation of hydrogen and representative organic fuels. Among important issues are possible changes in the morphology and dispersion, as well as specific interactions leading to the improved chemisorptive and catalytic properties in addition to the feasibility of long time operation of the discussed systems. PMID:24443590

  15. Electrocatalytic oxidation of small organic molecules in acid medium: enhancement of activity of noble metal nanoparticles and their alloys by supporting or modifying them with metal oxides. (United States)

    Kulesza, Pawel J; Pieta, Izabela S; Rutkowska, Iwona A; Wadas, Anna; Marks, Diana; Klak, Karolina; Stobinski, Leszek; Cox, James A


    Different approaches to enhancement of electrocatalytic activity of noble metal nanoparticles during oxidation of small organic molecules (namely potential fuels for low-temperature fuel cells such as methanol, ethanol and formic acid) are described. A physical approach to the increase of activity of catalytic nanoparticles (e.g. platinum or palladium) involves nanostructuring to obtain highly dispersed systems of high surface area. Recently, the feasibility of enhancing activity of noble metal systems through the formation of bimetallic (e.g. PtRu, PtSn, and PdAu) or even more complex (e.g. PtRuW, PtRuSn) alloys has been demonstrated. In addition to possible changes in the electronic properties of alloys, specific interactions between metals as well as chemical reactivity of the added components have been postulated. We address and emphasize here the possibility of utilization of noble metal and alloyed nanoparticles supported on robust but reactive high surface area metal oxides (e.g. WO3, MoO3, TiO2, ZrO2, V2O5, and CeO2) in oxidative electrocatalysis. This paper concerns the way in which certain inorganic oxides and oxo species can act effectively as supports for noble metal nanoparticles or their alloys during electrocatalytic oxidation of hydrogen and representative organic fuels. Among important issues are possible changes in the morphology and dispersion, as well as specific interactions leading to the improved chemisorptive and catalytic properties in addition to the feasibility of long time operation of the discussed systems.

  16. AT-101, a small molecule inhibitor of anti-apoptotic Bcl-2 family members, activates the SAPK/JNK pathway and enhances radiation-induced apoptosis

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    Rooswinkel Rogier


    Full Text Available Abstract Background Gossypol, a naturally occurring polyphenolic compound has been identified as a small molecule inhibitor of anti-apoptotic Bcl-2 family proteins. It induces apoptosis in a wide range of tumor cell lines and enhances chemotherapy- and radiation-induced cytotoxicity both in vitro and in vivo. Bcl-2 and related proteins are important inhibitors of apoptosis and frequently overexpressed in human tumors. Increased levels of these proteins confer radio- and chemoresistance and may be associated with poor prognosis. Consequently, inhibition of the anti-apoptotic functions of Bcl-2 family members represents a promising strategy to overcome resistance to anticancer therapies. Methods We tested the effect of (--gossypol, also denominated as AT-101, radiation and the combination of both on apoptosis induction in human leukemic cells, Jurkat T and U937. Because activation of the SAPK/JNK pathway is important for apoptosis induction by many different stress stimuli, and Bcl-XL is known to inhibit activation of SAPK/JNK, we also investigated the role of this signaling cascade in AT-101-induced apoptosis using a pharmacologic and genetic approach. Results AT-101 induced apoptosis in a time- and dose-dependent fashion, with ED50 values of 1.9 and 2.4 μM in Jurkat T and U937 cells, respectively. Isobolographic analysis revealed a synergistic interaction between AT-101 and radiation, which also appeared to be sequence-dependent. Like radiation, AT-101 activated SAPK/JNK which was blocked by the kinase inhibitor SP600125. In cells overexpressing a dominant-negative mutant of c-Jun, AT-101-induced apoptosis was significantly reduced. Conclusion Our data show that AT-101 strongly enhances radiation-induced apoptosis in human leukemic cells and indicate a requirement for the SAPK/JNK pathway in AT-101-induced apoptosis. This type of apoptosis modulation may overcome treatment resistance and lead to the development of new effective combination

  17. A novel small molecule, HK-156, inhibits lipopoly-saccharide-induced activation of NF-κB signaling and improves survival in mouse models of sepsis

    Institute of Scientific and Technical Information of China (English)

    Jian-ping FANG; Yang LIU; Jie LI; Wen-feng LIAO; You-hong HU; Kan DING


    Aim:To characterize a small molecule compound HK-156 as a novel inhibitor of the nuclear factor KB (NF-KB) signaling pathway.Methods:THP-1 monocytes and HEK293/hTLR4A-MD2-CD14 cells were tested.HK-156 and compound 809,an HK-156 analogue,were synthesized.A luciferase assay was used to evaluate the transcriptional activity of NF-κB.The levels of cytokines were measured with cytokine arrays,ELISA and quantitative PCR.An electrophoretic mobility shift assay (EMSA),immunofluor.escence,Western blot and mass spectrometry were used to investigate the molecular mechanisms underlying the actions of the agent.BALB/c mice chal lenged with lipopolysaccharide (LPS,15 mg/kg,ip) were used as a mouse experimental endotoxemia model.Results:In HEK293hTLR4/NF-κB-luc cells treated with LPS (1000 ng/mL),HK-156 inhibited the transcriptional activity of NF-κB in a concentration-dependent manner(IC50=6.54±0.37 μmol/L).Pretreatment of THP-1 monocytes with HK-156 (5,10 and 20 μmol/L)significantly inhibited LPS-induced release and production of TNF-α and IL-1β,attenuated LPS-induced translocation of NF-κB into the nucleus and its binding to DNA,and suppressed LPS-induced phosphorylation and degradation of IκBα,and phosphorylation of IKKβ and TGFβ-activated kinase (TAK1).Meanwhile,HK-156 (5,10 and 20 μmol/L) slightly suppressed LPS-induced activation of p38.The effect of HK-156 on LPS-induced activation of NF-κB signaling was dependent on thiol groups of cysteines in upstream proteins.In mouse models of sepsis,pre-injection of HK-156 (50 mg/kg,iv) significantly inhibited TNFα production and reduced the mortality caused by the lethal dose of LPS.Conclusion:HK-156 inhibits LPS-induced activation of NF-κB signaling by suppressing the phosphorylation of TAK1 in vitro,and exerts beneficial effects in a mouse sepsis model.HK 156 may therefore be a useful therapeutic agent for treating sepsis.

  18. Facilities for small-molecule crystallography at synchrotron sources. (United States)

    Barnett, Sarah A; Nowell, Harriott; Warren, Mark R; Wilcox, Andrian; Allan, David R


    Although macromolecular crystallography is a widely supported technique at synchrotron radiation facilities throughout the world, there are, in comparison, only very few beamlines dedicated to small-molecule crystallography. This limited provision is despite the increasing demand for beamtime from the chemical crystallography community and the ever greater overlap between systems that can be classed as either small macromolecules or large small molecules. In this article, a very brief overview of beamlines that support small-molecule single-crystal diffraction techniques will be given along with a more detailed description of beamline I19, a dedicated facility for small-molecule crystallography at Diamond Light Source.

  19. Effects of Small Molecule Calcium-Activated Chloride Channel Inhibitors on Structure and Function of Accessory Cholera Enterotoxin (Ace of Vibrio cholerae.

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    Tanaya Chatterjee

    Full Text Available Cholera pathogenesis occurs due to synergistic pro-secretory effects of several toxins, such as cholera toxin (CTX and Accessory cholera enterotoxin (Ace secreted by Vibrio cholerae strains. Ace activates chloride channels stimulating chloride/bicarbonate transport that augments fluid secretion resulting in diarrhea. These channels have been targeted for drug development. However, lesser attention has been paid to the interaction of chloride channel modulators with bacterial toxins. Here we report the modulation of the structure/function of recombinant Ace by small molecule calcium-activated chloride channel (CaCC inhibitors, namely CaCCinh-A01, digallic acid (DGA and tannic acid. Biophysical studies indicate that the unfolding (induced by urea free energy increases upon binding CaCCinh-A01 and DGA, compared to native Ace, whereas binding of tannic acid destabilizes the protein. Far-UV CD experiments revealed that the α-helical content of Ace-CaCCinh-A01 and Ace-DGA complexes increased relative to Ace. In contrast, binding to tannic acid had the opposite effect, indicating the loss of protein secondary structure. The modulation of Ace structure induced by CaCC inhibitors was also analyzed using docking and molecular dynamics (MD simulation. Functional studies, performed using mouse ileal loops and Ussing chamber experiments, corroborate biophysical data, all pointing to the fact that tannic acid destabilizes Ace, inhibiting its function, whereas DGA stabilizes the toxin with enhanced fluid accumulation in mouse ileal loop. The efficacy of tannic acid in mouse model suggests that the targeted modulation of Ace structure may be of therapeutic benefit for gastrointestinal disorders.

  20. Effects of Small Molecule Calcium-Activated Chloride Channel Inhibitors on Structure and Function of Accessory Cholera Enterotoxin (Ace) of Vibrio cholerae (United States)

    Chatterjee, Tanaya; Sheikh, Irshad Ali; Chakravarty, Devlina; Chakrabarti, Pinak; Sarkar, Paramita; Saha, Tultul; Chakrabarti, Manoj K.; Hoque, Kazi Mirajul


    Cholera pathogenesis occurs due to synergistic pro-secretory effects of several toxins, such as cholera toxin (CTX) and Accessory cholera enterotoxin (Ace) secreted by Vibrio cholerae strains. Ace activates chloride channels stimulating chloride/bicarbonate transport that augments fluid secretion resulting in diarrhea. These channels have been targeted for drug development. However, lesser attention has been paid to the interaction of chloride channel modulators with bacterial toxins. Here we report the modulation of the structure/function of recombinant Ace by small molecule calcium-activated chloride channel (CaCC) inhibitors, namely CaCCinh-A01, digallic acid (DGA) and tannic acid. Biophysical studies indicate that the unfolding (induced by urea) free energy increases upon binding CaCCinh-A01 and DGA, compared to native Ace, whereas binding of tannic acid destabilizes the protein. Far-UV CD experiments revealed that the α-helical content of Ace-CaCCinh-A01 and Ace-DGA complexes increased relative to Ace. In contrast, binding to tannic acid had the opposite effect, indicating the loss of protein secondary structure. The modulation of Ace structure induced by CaCC inhibitors was also analyzed using docking and molecular dynamics (MD) simulation. Functional studies, performed using mouse ileal loops and Ussing chamber experiments, corroborate biophysical data, all pointing to the fact that tannic acid destabilizes Ace, inhibiting its function, whereas DGA stabilizes the toxin with enhanced fluid accumulation in mouse ileal loop. The efficacy of tannic acid in mouse model suggests that the targeted modulation of Ace structure may be of therapeutic benefit for gastrointestinal disorders. PMID:26540279

  1. Organic synthesis toward small-molecule probes and drugs (United States)

    Schreiber, Stuart L.


    “Organic synthesis” is a compound-creating activity often focused on biologically active small molecules. This special issue of PNAS explores innovations and trends in the field that are enabling the synthesis of new types of small-molecule probes and drugs. This perspective article frames the research described in the special issue but also explores how these modern capabilities can both foster a new and more extensive view of basic research in the academy and promote the linkage of life-science research to the discovery of novel types of small-molecule therapeutics [Schreiber SL (2009) Chem Bio Chem 10:26–29]. This new view of basic research aims to bridge the chasm between basic scientific discoveries in life sciences and new drugs that treat the root cause of human disease—recently referred to as the “valley of death” for drug discovery. This perspective article describes new roles that modern organic chemistry will need to play in overcoming this challenge. PMID:21464328

  2. Domain-based small molecule binding site annotation

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    Dumontier Michel


    Full Text Available Abstract Background Accurate small molecule binding site information for a protein can facilitate studies in drug docking, drug discovery and function prediction, but small molecule binding site protein sequence annotation is sparse. The Small Molecule Interaction Database (SMID, a database of protein domain-small molecule interactions, was created using structural data from the Protein Data Bank (PDB. More importantly it provides a means to predict small molecule binding sites on proteins with a known or unknown structure and unlike prior approaches, removes large numbers of false positive hits arising from transitive alignment errors, non-biologically significant small molecules and crystallographic conditions that overpredict ion binding sites. Description Using a set of co-crystallized protein-small molecule structures as a starting point, SMID interactions were generated by identifying protein domains that bind to small molecules, using NCBI's Reverse Position Specific BLAST (RPS-BLAST algorithm. SMID records are available for viewing at The SMID-BLAST tool provides accurate transitive annotation of small-molecule binding sites for proteins not found in the PDB. Given a protein sequence, SMID-BLAST identifies domains using RPS-BLAST and then lists potential small molecule ligands based on SMID records, as well as their aligned binding sites. A heuristic ligand score is calculated based on E-value, ligand residue identity and domain entropy to assign a level of confidence to hits found. SMID-BLAST predictions were validated against a set of 793 experimental small molecule interactions from the PDB, of which 472 (60% of predicted interactions identically matched the experimental small molecule and of these, 344 had greater than 80% of the binding site residues correctly identified. Further, we estimate that 45% of predictions which were not observed in the PDB validation set may be true positives. Conclusion By

  3. Small-Molecule NSC59984 Restores p53 Pathway Signaling and Antitumor Effects against Colorectal Cancer via p73 Activation and Degradation of Mutant p53. (United States)

    Zhang, Shengliang; Zhou, Lanlan; Hong, Bo; van den Heuvel, A Pieter J; Prabhu, Varun V; Warfel, Noel A; Kline, Christina Leah B; Dicker, David T; Kopelovich, Levy; El-Deiry, Wafik S


    The tumor-suppressor p53 prevents cancer development via initiating cell-cycle arrest, cell death, repair, or antiangiogenesis processes. Over 50% of human cancers harbor cancer-causing mutant p53. p53 mutations not only abrogate its tumor-suppressor function, but also endow mutant p53 with a gain of function (GOF), creating a proto-oncogene that contributes to tumorigenesis, tumor progression, and chemo- or radiotherapy resistance. Thus, targeting mutant p53 to restore a wild-type p53 signaling pathway provides an attractive strategy for cancer therapy. We demonstrate that small-molecule NSC59984 not only restores wild-type p53 signaling, but also depletes mutant p53 GOF. NSC59984 induces mutant p53 protein degradation via MDM2 and the ubiquitin-proteasome pathway. NSC59984 restores wild-type p53 signaling via p73 activation, specifically in mutant p53-expressing colorectal cancer cells. At therapeutic doses, NSC59984 induces p73-dependent cell death in cancer cells with minimal genotoxicity and without evident toxicity toward normal cells. NSC59984 synergizes with CPT11 to induce cell death in mutant p53-expressing colorectal cancer cells and inhibits mutant p53-associated colon tumor xenograft growth in a p73-dependent manner in vivo. We hypothesize that specific targeting of mutant p53 may be essential for anticancer strategies that involve the stimulation of p73 in order to efficiently restore tumor suppression. Taken together, our data identify NSC59984 as a promising lead compound for anticancer therapy that acts by targeting GOF-mutant p53 and stimulates p73 to restore the p53 pathway signaling.

  4. Small-Molecule Hormones: Molecular Mechanisms of Action

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    Monika Puzianowska-Kuznicka


    Full Text Available Small-molecule hormones play crucial roles in the development and in the maintenance of an adult mammalian organism. On the molecular level, they regulate a plethora of biological pathways. Part of their actions depends on their transcription-regulating properties, exerted by highly specific nuclear receptors which are hormone-dependent transcription factors. Nuclear hormone receptors interact with coactivators, corepressors, basal transcription factors, and other transcription factors in order to modulate the activity of target genes in a manner that is dependent on tissue, age and developmental and pathophysiological states. The biological effect of this mechanism becomes apparent not earlier than 30–60 minutes after hormonal stimulus. In addition, small-molecule hormones modify the function of the cell by a number of nongenomic mechanisms, involving interaction with proteins localized in the plasma membrane, in the cytoplasm, as well as with proteins localized in other cellular membranes and in nonnuclear cellular compartments. The identity of such proteins is still under investigation; however, it seems that extranuclear fractions of nuclear hormone receptors commonly serve this function. A direct interaction of small-molecule hormones with membrane phospholipids and with mRNA is also postulated. In these mechanisms, the reaction to hormonal stimulus appears within seconds or minutes.

  5. New small molecules targeting apoptosis and cell viability in osteosarcoma.

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    Doris Maugg

    Full Text Available Despite the option of multimodal therapy in the treatment strategies of osteosarcoma (OS, the most common primary malignant bone tumor, the standard therapy has not changed over the last decades and still involves multidrug chemotherapy and radical surgery. Although successfully applied in many patients a large number of patients eventually develop recurrent or metastatic disease in which current therapeutic regimens often lack efficacy. Thus, new therapeutic strategies are urgently needed. In this study, we performed a phenotypic high-throughput screening campaign using a 25,000 small-molecule diversity library to identify new small molecules selectively targeting osteosarcoma cells. We could identify two new small molecules that specifically reduced cell viability in OS cell lines U2OS and HOS, but affected neither hepatocellular carcinoma cell line (HepG2 nor primary human osteoblasts (hOB. In addition, the two compounds induced caspase 3 and 7 activity in the U2OS cell line. Compared to conventional drugs generally used in OS treatment such as doxorubicin, we indeed observed a greater sensitivity of OS cell viability to the newly identified compounds compared to doxorubicin and staurosporine. The p53-negative OS cell line Saos-2 almost completely lacked sensitivity to compound treatment that could indicate a role of p53 in the drug response. Taken together, our data show potential implications for designing more efficient therapies in OS.

  6. Chemisorption and Reactions of Small Molecules on Small Gold Particles

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    Geoffrey C. Bond


    Full Text Available The activity of supported gold particles for a number of oxidations and hydrogenations starts to increase dramatically as the size falls below ~3 nm. This is accompanied by an increased propensity to chemisorption, especially of oxygen and hydrogen. The explanation for these phenomena has to be sought in kinetic analysis that connects catalytic activity with the strength and extent of chemisorption of the reactants, the latter depending on the electronic structure of the gold atoms constituting the active centre. Examination of the changes to the utilisation of electrons as particle size is decreased points to loss of metallic character at about 3 nm, as energy bands are replaced by levels, and a band gap appears. Detailed consideration of the Arrhenius parameters (E and ln A for CO oxidation points clearly to a step-change in activity at the point where metallic character is lost, as opposed to there being a monotonic dependence of rate on a physical property such as the fraction of atoms at corners or edges of particles. The deplorable scarcity of kinetic information on other reactions makes extension of this analysis difficult, but non-metallic behaviour is an unavoidable property of very small gold particles, and therefore cannot be ignored when seeking to explain their exceptional activity.

  7. Fluorescence Emission from Small Molecules Containing Amino Group

    Institute of Scientific and Technical Information of China (English)


    After the treatment of oxygen gas, the small molecules containing amine group could emit fluorescence. Oxidation was believed to play an important role in the formation of fluorescence centers. Compared to previous results, both small molecules and macromolecules might have the same fluorescence centers.

  8. Bioinspired assembly of small molecules in cell milieu. (United States)

    Wang, Huaimin; Feng, Zhaoqianqi; Xu, Bing


    Self-assembly, the autonomous organization of components to form patterns or structures, is a prevalent process in nature at all scales. Particularly, biological systems offer remarkable examples of diverse structures (as well as building blocks) and processes resulting from self-assembly. The exploration of bioinspired assemblies not only allows for mimicking the structures of living systems, but it also leads to functions for applications in different fields that benefit humans. In the last several decades, efforts on understanding and controlling self-assembly of small molecules have produced a large library of candidates for developing the biomedical applications of assemblies of small molecules. Moreover, recent findings in biology have provided new insights on the assemblies of small molecules to modulate essential cellular processes (such as apoptosis). These observations indicate that the self-assembly of small molecules, as multifaceted entities and processes to interact with multiple proteins, can have profound biological impacts on cells. In this review, we illustrate that the generation of assemblies of small molecules in cell milieu with their interactions with multiple cellular proteins for regulating cellular processes can result in primary phenotypes, thus providing a fundamentally new molecular approach for controlling cell behavior. By discussing the correlation between molecular assemblies in nature and the assemblies of small molecules in cell milieu, illustrating the functions of the assemblies of small molecules, and summarizing some guiding principles, we hope this review will stimulate more molecular scientists to explore the bioinspired self-assembly of small molecules in cell milieu.

  9. Stability of lyophilized human platelets loaded with small molecule carbohydrates. (United States)

    Wang, J X; Yang, C; Wan, W; Liu, M X; Ren, S P; Quan, G B; Han, Y


    Long-term preservation of platelets is a great challenge for blood transfusion centers, due to the required narrow storage temperature arange (22 ± 2 degree C). Short shelf life and potential bacterial growth often lead to the shortage of high-quality platelets. Freeze-dried preservation is thus believed to be a potential solution for long-term platelet storage without losing the hemostasis function. Here we report a new platelet preservation method, which uses small molecule carbohydrates to extend storage time and to maintain platelet function. The activities of lyophilized platelets that were stabilized with small molecule carbohydrate (e.g., cell viability, mean platelet volume, activation characteristics, and aggregation kinetics) were maintained after storage of 30, 60, and 90 days at room temperature, 4 degree C, and -20 degree C. The recovery of freeze-dried platelets was 87 percent in comparison to fresh platelets. The mean platelet volume of rehydrated platelets increased (from 6.8 fl to 8.0 fl). About 40 percent of rehydrated platelets was in the early-activated stage (PCA-1 positive) and 30 percent was in the terminal-activated stage (CD62P positive). The cell viability was about 60 percent as measured with CMFDA vital probes. The aggregation rate of rehydrated platelets after 90-day storage was similar to fresh platelets stored at 22 degree C ± 2 degree C.

  10. Allosteric small-molecule kinase inhibitors

    DEFF Research Database (Denmark)

    Wu, Peng; Clausen, Mads Hartvig; Nielsen, Thomas E.


    current barriers of kinase inhibitors, including poor selectivity and emergence of drug resistance. In spite of the small number of identified allosteric inhibitors in comparison with that of inhibitors targeting the ATP pocket, encouraging results, such as the FDA-approval of the first small...

  11. A general strategy to construct small molecule biosensors in eukaryotes (United States)

    Feng, Justin; Jester, Benjamin W; Tinberg, Christine E; Mandell, Daniel J; Antunes, Mauricio S; Chari, Raj; Morey, Kevin J; Rios, Xavier; Medford, June I; Church, George M; Fields, Stanley; Baker, David


    Biosensors for small molecules can be used in applications that range from metabolic engineering to orthogonal control of transcription. Here, we produce biosensors based on a ligand-binding domain (LBD) by using a method that, in principle, can be applied to any target molecule. The LBD is fused to either a fluorescent protein or a transcriptional activator and is destabilized by mutation such that the fusion accumulates only in cells containing the target ligand. We illustrate the power of this method by developing biosensors for digoxin and progesterone. Addition of ligand to yeast, mammalian, or plant cells expressing a biosensor activates transcription with a dynamic range of up to ~100-fold. We use the biosensors to improve the biotransformation of pregnenolone to progesterone in yeast and to regulate CRISPR activity in mammalian cells. This work provides a general methodology to develop biosensors for a broad range of molecules in eukaryotes. DOI: PMID:26714111

  12. Sorption of small molecules in polymeric media (United States)

    Camboni, Federico; Sokolov, Igor M.


    We discuss the sorption of penetrant molecules from the gas phase by a polymeric medium within a model which is very close in spirit to the dual sorption mode model: the penetrant molecules are partly dissolved within the polymeric matrix, partly fill the preexisting voids. The only difference with the initial dual sorption mode situation is the assumption that the two populations of molecules are in equilibrium with each other. Applying basic thermodynamics principles we obtain the dependence of the penetrant concentration on the pressure in the gas phase and find that this is expressed via the Lambert W-function, a different functional form than the one proposed by dual sorption mode model. The Lambert-like isotherms appear universally at low and moderate pressures and originate from the assumption that the internal energy in a polymer-penetrant-void ternary mixture is (in the lowest order) a bilinear form in the concentrations of the three components. Fitting the existing data shows that in the domain of parameters where the dual sorption mode model is typically applied, the Lambert function, which describes the same behavior as the one proposed by the gas-polymer matrix model, fits the data equally well.

  13. Highly parallel translation of DNA sequences into small molecules.

    Directory of Open Access Journals (Sweden)

    Rebecca M Weisinger

    Full Text Available A large body of in vitro evolution work establishes the utility of biopolymer libraries comprising 10(10 to 10(15 distinct molecules for the discovery of nanomolar-affinity ligands to proteins. Small-molecule libraries of comparable complexity will likely provide nanomolar-affinity small-molecule ligands. Unlike biopolymers, small molecules can offer the advantages of cell permeability, low immunogenicity, metabolic stability, rapid diffusion and inexpensive mass production. It is thought that such desirable in vivo behavior is correlated with the physical properties of small molecules, specifically a limited number of hydrogen bond donors and acceptors, a defined range of hydrophobicity, and most importantly, molecular weights less than 500 Daltons. Creating a collection of 10(10 to 10(15 small molecules that meet these criteria requires the use of hundreds to thousands of diversity elements per step in a combinatorial synthesis of three to five steps. With this goal in mind, we have reported a set of mesofluidic devices that enable DNA-programmed combinatorial chemistry in a highly parallel 384-well plate format. Here, we demonstrate that these devices can translate DNA genes encoding 384 diversity elements per coding position into corresponding small-molecule gene products. This robust and efficient procedure yields small molecule-DNA conjugates suitable for in vitro evolution experiments.

  14. A new class of pluripotent stem cell cytotoxic small molecules.

    Directory of Open Access Journals (Sweden)

    Mark Richards

    Full Text Available A major concern in Pluripotent Stem Cell (PSC-derived cell replacement therapy is the risk of teratoma formation from contaminating undifferentiated cells. Removal of undifferentiated cells from differentiated cultures is an essential step before PSC-based cell therapies can be safely deployed in a clinical setting. We report a group of novel small molecules that are cytotoxic to PSCs. Our data indicates that these molecules are specific and potent in their activity allowing rapid eradication of undifferentiated cells. Experiments utilizing mixed PSC and primary human neuronal and cardiomyocyte cultures demonstrate that up to a 6-fold enrichment for specialized cells can be obtained without adversely affecting cell viability and function. Several structural variants were synthesized to identify key functional groups and to improve specificity and efficacy. Comparative microarray analysis and ensuing RNA knockdown studies revealed involvement of the PERK/ATF4/DDIT3 ER stress pathway. Surprisingly, cell death following ER stress induction was associated with a concomitant decrease in endogenous ROS levels in PSCs. Undifferentiated cells treated with these molecules preceding transplantation fail to form teratomas in SCID mice. Furthermore, these molecules remain non-toxic and non-teratogenic to zebrafish embryos suggesting that they may be safely used in vivo.

  15. Identifying a Small Molecule Blocking Antigen Presentation in Autoimmune Thyroiditis. (United States)

    Li, Cheuk Wun; Menconi, Francesca; Osman, Roman; Mezei, Mihaly; Jacobson, Eric M; Concepcion, Erlinda; David, Chella S; Kastrinsky, David B; Ohlmeyer, Michael; Tomer, Yaron


    We previously showed that an HLA-DR variant containing arginine at position 74 of the DRβ1 chain (DRβ1-Arg74) is the specific HLA class II variant conferring risk for autoimmune thyroid diseases (AITD). We also identified 5 thyroglobulin (Tg) peptides that bound to DRβ1-Arg74. We hypothesized that blocking the binding of these peptides to DRβ1-Arg74 could block the continuous T-cell activation in thyroiditis needed to maintain the autoimmune response to the thyroid. The aim of the current study was to identify small molecules that can block T-cell activation by Tg peptides presented within DRβ1-Arg74 pockets. We screened a large and diverse library of compounds and identified one compound, cepharanthine that was able to block peptide binding to DRβ1-Arg74. We then showed that Tg.2098 is the dominant peptide when inducing experimental autoimmune thyroiditis (EAT) in NOD mice expressing human DRβ1-Arg74. Furthermore, cepharanthine blocked T-cell activation by thyroglobulin peptides, in particular Tg.2098 in mice that were induced with EAT. For the first time we identified a small molecule that can block Tg peptide binding and presentation to T-cells in autoimmune thyroiditis. If confirmed cepharanthine could potentially have a role in treating human AITD.

  16. Small-Molecule Binding Aptamers: Selection Strategies, Characterization, and Applications (United States)

    Ruscito, Annamaria; DeRosa, Maria


    Aptamers are single-stranded, synthetic oligonucleotides that fold into 3-dimensional shapes capable of binding non-covalently with high affinity and specificity to a target molecule. They are generated via an in vitro process known as the Systematic Evolution of Ligands by EXponential enrichment, from which candidates are screened and characterized, and then applied in aptamer-based biosensors for target detection. Aptamers for small molecule targets such as toxins, antibiotics, molecular markers, drugs, and heavy metals will be the focus of this review. Their accurate detection is ultimately needed for the protection and wellbeing of humans and animals. However, issues such as the drastic difference in size of the aptamer and small molecule make it challenging to select, characterize, and apply aptamers for the detection of small molecules. Thus, recent (since 2012) notable advances in small molecule aptamers, which have overcome some of these challenges, are presented here, while defining challenges that still exist are discussed

  17. Inhibition of HIV-1 Reverse Transcriptase Dimerization by Small Molecules. (United States)

    Tintori, Cristina; Corona, Angela; Esposito, Francesca; Brai, Annalaura; Grandi, Nicole; Ceresola, Elisa Rita; Clementi, Massimo; Canducci, Filippo; Tramontano, Enzo; Botta, Maurizio


    Because HIV-1 reverse transcriptase is an enzyme whose catalytic activity depends on its heterodimeric structure, this system could be a target for inhibitors that perturb the interactions between the protein subunits, p51 and p66. We previously demonstrated that the small molecule MAS0 reduced the association of the two RT subunits and simultaneously inhibited both the polymerase and ribonuclease H activities. In this study, some analogues of MAS0 were rationally selected by docking studies and evaluated in vitro for their ability to disrupt dimeric assembly. Two inhibitors were identified with improved activity compared to MAS0. This study lays the basis for the rational design of more potent inhibitors of RT dimerization.

  18. Unique small molecule entry inhibitors of hemorrhagic fever arenaviruses. (United States)

    Lee, Andrew M; Rojek, Jillian M; Spiropoulou, Christina F; Gundersen, Anette T; Jin, Wei; Shaginian, Alex; York, Joanne; Nunberg, Jack H; Boger, Dale L; Oldstone, Michael B A; Kunz, Stefan


    Viral hemorrhagic fevers caused by the arenaviruses Lassa virus in Africa and Machupo, Guanarito, Junin, and Sabia virus in South America are among the most devastating emerging human diseases with fatality rates of 15-35% and a limited antiviral therapeutic repertoire available. Here we used high throughput screening of synthetic combinatorial small molecule libraries to identify inhibitors of arenavirus infection using pseudotyped virion particles bearing the glycoproteins (GPs) of highly pathogenic arenaviruses. Our screening efforts resulted in the discovery of a series of novel small molecule inhibitors of viral entry that are highly active against both Old World and New World hemorrhagic arenaviruses. We observed potent inhibition of infection of human and primate cells with live hemorrhagic arenaviruses (IC(50)=500-800 nm). Investigations of the mechanism of action revealed that the candidate compounds efficiently block pH-dependent fusion by the arenavirus GPs (IC(50) of 200-350 nm). Although our lead compounds were potent against phylogenetically distant arenaviruses, they did not show activity against other enveloped viruses with class I viral fusion proteins, indicating specificity for arenavirus GP-mediated membrane fusion.

  19. Phase Transition Induced by Small Molecules in Confined Copolymer Films

    Institute of Scientific and Technical Information of China (English)

    ZHOU Ling


    We investigate the phase transition induced by small molecules in confined copolymer films by using density functional theory.It is found that the addition of small molecules can effectively promote the phase separation of copolymers.In a symmetric diblock copolymer film,the affinity and concentration of small molecules play an important role in the structure transjtions.The disordered-lamellar transitions lamellar-lamellar transitions and the re-entrant transitions of the same structures are observed.Our results have potential applications in the fabrication of new functional materials.

  20. Global analysis of small molecule binding to related protein targets.

    Directory of Open Access Journals (Sweden)

    Felix A Kruger


    Full Text Available We report on the integration of pharmacological data and homology information for a large scale analysis of small molecule binding to related targets. Differences in small molecule binding have been assessed for curated pairs of human to rat orthologs and also for recently diverged human paralogs. Our analysis shows that in general, small molecule binding is conserved for pairs of human to rat orthologs. Using statistical tests, we identified a small number of cases where small molecule binding is different between human and rat, some of which had previously been reported in the literature. Knowledge of species specific pharmacology can be advantageous for drug discovery, where rats are frequently used as a model system. For human paralogs, we demonstrate a global correlation between sequence identity and the binding of small molecules with equivalent affinity. Our findings provide an initial general model relating small molecule binding and sequence divergence, containing the foundations for a general model to anticipate and predict within-target-family selectivity.

  1. Targeting Mitogen-Activated Protein Kinase-Activated Protein Kinase 2 (MAPKAPK2, MK2): Medicinal Chemistry Efforts To Lead Small Molecule Inhibitors to Clinical Trials. (United States)

    Fiore, Mario; Forli, Stefano; Manetti, Fabrizio


    The p38/MAPK-activated kinase 2 (MK2) pathway is involved in a series of pathological conditions (inflammation diseases and metastasis) and in the resistance mechanism to antitumor agents. None of the p38 inhibitors entered advanced clinical trials because of their unwanted systemic side effects. For this reason, MK2 was identified as an alternative target to block the pathway but avoiding the side effects of p38 inhibition. However, ATP-competitive MK2 inhibitors suffered from low solubility, poor cell permeability, and scarce kinase selectivity. Fortunately, non-ATP-competitive inhibitors of MK2 have been already discovered that allowed circumventing the selectivity issue. These compounds showed the additional advantage to be effective at lower concentrations in comparison to the ATP-competitive inhibitors. Therefore, although the significant difficulties encountered during the development of these inhibitors, MK2 is still considered as an attractive target to treat inflammation and related diseases to prevent tumor metastasis and to increase tumor sensitivity to chemotherapeutics.

  2. A Prospective Method to Guide Small Molecule Drug Design (United States)

    Johnson, Alan T.


    At present, small molecule drug design follows a retrospective path when considering what analogs are to be made around a current hit or lead molecule with the focus often on identifying a compound with higher intrinsic potency. What this approach overlooks is the simultaneous need to also improve the physicochemical (PC) and pharmacokinetic (PK)…

  3. Biocatalysts and small molecule products from metagenomic studies. (United States)

    Iqbal, Hala A; Feng, Zhiyang; Brady, Sean F


    The vast majority of bacteria present in environmental samples have never been cultured and therefore have not been exploited for the ability to produce useful biocatalysts or collections of biocatalysts generating interesting small molecules. Metagenomic libraries constructed using DNA extracted directly from natural bacterial communities offer access to the genetic information present in the genomes of these as yet uncultured bacteria. This review highlights recent efforts to recover both discrete enzymes and small molecules from metagenomic libraries.

  4. TMAO: A small molecule of great expectations. (United States)

    Ufnal, Marcin; Zadlo, Anna; Ostaszewski, Ryszard


    Trimethylamine N-oxide (TMAO) is a small organic compound whose concentration in blood increases after ingesting dietary l-carnitine and phosphatidylcholine. Recent clinical studies show a positive correlation between elevated plasma levels of TMAO and an increased risk for major adverse cardiovascular events defined as death, myocardial infarction, or stroke. Several experimental studies suggest a possible contribution of TMAO to the etiology of cardiovascular diseases by affecting lipid and hormonal homeostasis. On the other hand, TMAO-rich seafood, which is an important source of protein and vitamins in the Mediterranean diet, has been considered beneficial for the circulatory system. Although in humans TMAO is known mainly as a waste product of choline metabolism, a number of studies suggest an involvement of TMAO in important biological functions in numerous organisms, ranging from bacteria to mammals. For example, cells use TMAO to maintain cell volume under conditions of osmotic and hydrostatic pressure stresses. In this article, we reviewed well-established chemical and biological properties of TMAO and dietary sources of TMAO, as well as looked at the studies suggesting possible involvement of TMAO in the etiology of cardiovascular and other diseases, such as kidney failure, diabetes, and cancer.

  5. Molecules Great and Small: The Complement System. (United States)

    Mathern, Douglas R; Heeger, Peter S


    The complement cascade, traditionally considered an effector arm of innate immunity required for host defense against pathogens, is now recognized as a crucial pathogenic mediator of various kidney diseases. Complement components produced by the liver and circulating in the plasma undergo activation through the classical and/or mannose-binding lectin pathways to mediate anti-HLA antibody-initiated kidney transplant rejection and autoantibody-initiated GN, the latter including membranous glomerulopathy, antiglomerular basement membrane disease, and lupus nephritis. Inherited and/or acquired abnormalities of complement regulators, which requisitely limit restraint on alternative pathway complement activation, contribute to the pathogenesis of the C3 nephropathies and atypical hemolytic uremic syndrome. Increasing evidence links complement produced by endothelial cells and/or tubular cells to the pathogenesis of kidney ischemia-reperfusion injury and progressive kidney fibrosis. Data emerging since the mid-2000s additionally show that immune cells, including T cells and antigen-presenting cells, produce alternative pathway complement components during cognate interactions. The subsequent local complement activation yields production of the anaphylatoxins C3a and C5a, which bind to their respective receptors (C3aR and C5aR) on both partners to augment effector T-cell proliferation and survival, while simultaneously inhibiting regulatory T-cell induction and function. This immune cell-derived complement enhances pathogenic alloreactive T-cell immunity that results in transplant rejection and likely contributes to the pathogenesis of other T cell-mediated kidney diseases. C5a/C5aR ligations on neutrophils have additionally been shown to contribute to vascular inflammation in models of ANCA-mediated renal vasculitis. New translational immunology efforts along with the development of pharmacologic agents that block human complement components and receptors now permit

  6. Hydrogen. A small molecule with large impact

    Energy Technology Data Exchange (ETDEWEB)

    Gehrke, H.; Ruthardt, K.; Mathiak, J.; Roosen, C. [Uhde GmbH, Dortmund (Germany)


    The first section of the presentation will provide general information about hydrogen including physical data, natural abundance, production and consumption figures. This will be followed by detailed information about current industrial production routes for hydrogen. Main on-purpose production for hydrogen is by classical steam reforming (SR) of natural gas. A brief overview of most important steps in stream reforming is given including reforming section, CO conversion and gas purification. Also the use of heavier than methane feedstocks and refinery off-gases is discussed. Alternative routes for hydrogen production or production of synthesis gas are autothermal reforming (ATR) or partial oxidation (POX). Pros and Cons for each specific technology are given and discussed. Gasification, especially gasification of renewable feedstocks, is a further possibility to produce hydrogen or synthesis gas. New developments and current commercial processes are presented. Hydrogen from electrolysis plants has only a small share on the hydrogen production slate, but in some cases this hydrogen is a suitable feedstock for niche applications with future potential. Finally, production of hydrogen by solar power as a new route is discussed. The final section focuses on the use of hydrogen. Classical applications are hydrogenation reactions in refineries, like HDS, HDN, hydrocracking and hydrofinishing. But, with an increased demand for liquid fuels for transportation or power supply, hydrogen becomes a key player in future as an energy source. Use of hydrogen in synthesis gas for the production of liquid fuels via Fischer-Tropsch synthesis or coal liquefaction is discussed as well as use of pure hydrogen in fuel cells. Additional, new application for biomass-derived feedstocks are discussed. (orig.)

  7. Inhibition of DNA glycosylases via small molecule purine analogs.

    Directory of Open Access Journals (Sweden)

    Aaron C Jacobs

    Full Text Available Following the formation of oxidatively-induced DNA damage, several DNA glycosylases are required to initiate repair of the base lesions that are formed. Recently, NEIL1 and other DNA glycosylases, including OGG1 and NTH1 were identified as potential targets in combination chemotherapeutic strategies. The potential therapeutic benefit for the inhibition of DNA glycosylases was validated by demonstrating synthetic lethality with drugs that are commonly used to limit DNA replication through dNTP pool depletion via inhibition of thymidylate synthetase and dihydrofolate reductase. Additionally, NEIL1-associated synthetic lethality has been achieved in combination with Fanconi anemia, group G. As a prelude to the development of strategies to exploit the potential benefits of DNA glycosylase inhibition, it was necessary to develop a reliable high-throughput screening protocol for this class of enzymes. Using NEIL1 as the proof-of-principle glycosylase, a fluorescence-based assay was developed that utilizes incision of site-specifically modified oligodeoxynucleotides to detect enzymatic activity. This assay was miniaturized to a 1536-well format and used to screen small molecule libraries for inhibitors of the combined glycosylase/AP lyase activities. Among the top hits of these screens were several purine analogs, whose postulated presence in the active site of NEIL1 was consistent with the paradigm of NEIL1 recognition and excision of damaged purines. Although a subset of these small molecules could inhibit other DNA glycosylases that excise oxidatively-induced DNA adducts, they could not inhibit a pyrimidine dimer-specific glycosylase.

  8. Significant blockade of multiple receptor tyrosine kinases by MGCD516 (Sitravatinib), a novel small molecule inhibitor, shows potent anti-tumor activity in preclinical models of sarcoma. (United States)

    Patwardhan, Parag P; Ivy, Kathryn S; Musi, Elgilda; de Stanchina, Elisa; Schwartz, Gary K


    Sarcomas are rare but highly aggressive mesenchymal tumors with a median survival of 10-18 months for metastatic disease. Mutation and/or overexpression of many receptor tyrosine kinases (RTKs) including c-Met, PDGFR, c-Kit and IGF1-R drive defective signaling pathways in sarcomas. MGCD516 (Sitravatinib) is a novel small molecule inhibitor targeting multiple RTKs involved in driving sarcoma cell growth. In the present study, we evaluated the efficacy of MGCD516 both in vitro and in mouse xenograft models in vivo. MGCD516 treatment resulted in significant blockade of phosphorylation of potential driver RTKs and induced potent anti-proliferative effects in vitro. Furthermore, MGCD516 treatment of tumor xenografts in vivo resulted in significant suppression of tumor growth. Efficacy of MGCD516 was superior to imatinib and crizotinib, two other well-studied multi-kinase inhibitors with overlapping target specificities, both in vitro and in vivo. This is the first report describing MGCD516 as a potent multi-kinase inhibitor in different models of sarcoma, superior to imatinib and crizotinib. Results from this study showing blockade of multiple driver signaling pathways provides a rationale for further clinical development of MGCD516 for the treatment of patients with soft-tissue sarcoma.

  9. Small molecule inhibitors of HCV replication from Pomegranate (United States)

    Reddy, B. Uma; Mullick, Ranajoy; Kumar, Anuj; Sudha, Govindarajan; Srinivasan, Narayanaswamy; Das, Saumitra


    Hepatitis C virus (HCV) is the causative agent of end-stage liver disease. Recent advances in the last decade in anti HCV treatment strategies have dramatically increased the viral clearance rate. However, several limitations are still associated, which warrant a great need of novel, safe and selective drugs against HCV infection. Towards this objective, we explored highly potent and selective small molecule inhibitors, the ellagitannins, from the crude extract of Pomegranate (Punica granatum) fruit peel. The pure compounds, punicalagin, punicalin, and ellagic acid isolated from the extract specifically blocked the HCV NS3/4A protease activity in vitro. Structural analysis using computational approach also showed that ligand molecules interact with the catalytic and substrate binding residues of NS3/4A protease, leading to inhibition of the enzyme activity. Further, punicalagin and punicalin significantly reduced the HCV replication in cell culture system. More importantly, these compounds are well tolerated ex vivo and`no observed adverse effect level' (NOAEL) was established upto an acute dose of 5000 mg/kg in BALB/c mice. Additionally, pharmacokinetics study showed that the compounds are bioavailable. Taken together, our study provides a proof-of-concept approach for the potential use of antiviral and non-toxic principle ellagitannins from pomegranate in prevention and control of HCV induced complications.

  10. Differentiating Alzheimer disease-associated aggregates with small molecules. (United States)

    Honson, Nicolette S; Johnson, Ronald L; Huang, Wenwei; Inglese, James; Austin, Christopher P; Kuret, Jeff


    Alzheimer disease is diagnosed postmortem by the density and spatial distribution of beta-amyloid plaques and tau-bearing neurofibrillary tangles. The major protein component of each lesion adopts cross-beta-sheet conformation capable of binding small molecules with submicromolar affinity. In many cases, however, Alzheimer pathology overlaps with Lewy body disease, characterized by the accumulation of a third cross-beta-sheet forming protein, alpha-synuclein. To determine the feasibility of distinguishing tau aggregates from beta-amyloid and alpha-synuclein aggregates with small molecule probes, a library containing 72,455 small molecules was screened for antagonists of tau-aggregate-mediated changes in Thioflavin S fluorescence, followed by secondary screens to distinguish the relative affinity for each substrate protein. Results showed that >10-fold binding selectivity among substrates could be achieved, with molecules selective for tau aggregates containing at least three aromatic or rigid moieties connected by two rotatable bonds.

  11. Decoupling Activation of Heme Biosynthesis from Anaerobic Toxicity in a Molecule Active in Staphylococcus aureus


    Dutter, Brendan F.; Mike, Laura A.; Reid, Paul R.; Chong, Katherine M.; Ramos-Hunter, Susan J.; Skaar, Eric P.; Sulikowski, Gary A.


    Small molecules active in the pathogenic bacterium Staphylococcus aureus are valuable tools for the study of its basic biology and pathogenesis, and many molecules may provide leads for novel therapeutics. We have previously reported a small molecule, 1, which activates endogenous heme biosynthesis in S. aureus, leading to an accumulation of intracellular heme. In addition to this novel activity, 1 also exhibits toxicity towards S. aureus growing under fermentative conditions. To determine if...

  12. Synchrotron radiation VUV double photoionization of some small molecules

    Institute of Scientific and Technical Information of China (English)

    Zhao Yu-Jie; Shan Xiao-Bin; Sheng Liu-Si; Wang Zhen-Ya; Zhang Jie; Yu Chun-Ri


    The VUV double photoionizations of small molecules(NO, CO, CO2, CS2, OSC and NH3)were investigated with photoionization mass spectroscopy using synchrotron radiation. The double ionization energies of molecules were determined with photoionization efficiency spectroscopy. The total energies of these molecules and their parent dications (NO2+, CO2+, CO2+2,CS2+2,OS2+C and NH2+3)were calculated using the Gaussian 03 program and Gaussian 2calculations. Then, the adiabatic double ionization energies of the molecules were predicated by using high accuracy energy mode. The experimental double ionization energies of these small molecules were all in reasonable agreement with their respective calculated adiabatic double ionization energies. The mechanisms of double photoionization of these molecules were discussed based on a comparison of our experimental results with those predicted theoretically. The equilibrium geometries and harmonic vibrational frequencies of molecules and their parent dications were calculated by using the MP2(full)method. The differences in configurations between these molecules and their parent dications were also discussed on the basis of theoretical calculations.

  13. The small molecule curcumin analog FLLL32 induces apoptosis in melanoma cells via STAT3 inhibition and retains the cellular response to cytokines with anti-tumor activity

    Directory of Open Access Journals (Sweden)

    Young Gregory S


    Full Text Available Abstract Background We characterized the biologic effects of a novel small molecule STAT3 pathway inhibitor that is derived from the natural product curcumin. We hypothesized this lead compound would specifically inhibit the STAT3 signaling pathway to induce apoptosis in melanoma cells. Results FLLL32 specifically reduced STAT3 phosphorylation at Tyr705 (pSTAT3 and induced apoptosis at micromolar amounts in human melanoma cell lines and primary melanoma cultures as determined by annexin V/propidium iodide staining and immunoblot analysis. FLLL32 treatment reduced expression of STAT3-target genes, induced caspase-dependent apoptosis, and reduced mitochondrial membrane potential. FLLL32 displayed specificity for STAT3 over other homologous STAT proteins. In contrast to other STAT3 pathway inhibitors (WP1066, JSI-124, Stattic, FLLL32 did not abrogate IFN-γ-induced pSTAT1 or downstream STAT1-mediated gene expression as determined by Real Time PCR. In addition, FLLL32 did not adversely affect the function or viability of immune cells from normal donors. In peripheral blood mononuclear cells (PBMCs, FLLL32 inhibited IL-6-induced pSTAT3 but did not reduce signaling in response to immunostimulatory cytokines (IFN-γ, IL 2. Treatment of PBMCs or natural killer (NK cells with FLLL32 also did not decrease viability or granzyme b and IFN-γ production when cultured with K562 targets as compared to vehicle (DMSO. Conclusions These data suggest that FLLL32 represents a lead compound that could serve as a platform for further optimization to develop improved STAT3 specific inhibitors for melanoma therapy.

  14. Strategy to discover diverse optimal molecules in the small molecule universe. (United States)

    Rupakheti, Chetan; Virshup, Aaron; Yang, Weitao; Beratan, David N


    The small molecule universe (SMU) is defined as a set of over 10(60) synthetically feasible organic molecules with molecular weight less than ∼500 Da. Exhaustive enumerations and evaluation of all SMU molecules for the purpose of discovering favorable structures is impossible. We take a stochastic approach and extend the ACSESS framework ( Virshup et al. J. Am. Chem. Soc. 2013 , 135 , 7296 - 7303 ) to develop diversity oriented molecular libraries that can generate a set of compounds that is representative of the small molecule universe and that also biases the library toward favorable physical property values. We show that the approach is efficient compared to exhaustive enumeration and to existing evolutionary algorithms for generating such libraries by testing in the NKp fitness landscape model and in the fully enumerated GDB-9 chemical universe containing 3 × 10(5) molecules.

  15. Cancer Immunotherapy: Selected Targets and Small-Molecule Modulators. (United States)

    Weinmann, Hilmar


    There is a significant amount of excitement in the scientific community around cancer immunotherapy, as this approach has renewed hope for many cancer patients owing to some recent successes in the clinic. Currently available immuno-oncology therapeutics under clinical development and on the market are mostly biologics (antibodies, proteins, engineered cells, and oncolytic viruses). However, modulation of the immune system with small molecules offers several advantages that may be complementary and potentially synergistic to the use of large biologicals. Therefore, the discovery and development of novel small-molecule modulators is a rapidly growing research area for medicinal chemists working in cancer immunotherapy. This review provides a brief introduction into recent trends related to selected targets and pathways for cancer immunotherapy and their small-molecule pharmacological modulators.

  16. Small-molecule discovery from DNA-encoded chemical libraries. (United States)

    Kleiner, Ralph E; Dumelin, Christoph E; Liu, David R


    Researchers seeking to improve the efficiency and cost effectiveness of the bioactive small-molecule discovery process have recently embraced selection-based approaches, which in principle offer much higher throughput and simpler infrastructure requirements compared with traditional small-molecule screening methods. Since selection methods benefit greatly from an information-encoding molecule that can be readily amplified and decoded, several academic and industrial groups have turned to DNA as the basis for library encoding and, in some cases, library synthesis. The resulting DNA-encoded synthetic small-molecule libraries, integrated with the high sensitivity of PCR and the recent development of ultra high-throughput DNA sequencing technology, can be evaluated very rapidly for binding or bond formation with a target of interest while consuming minimal quantities of material and requiring only modest investments of time and equipment. In this tutorial review we describe the development of two classes of approaches for encoding chemical structures and reactivity with DNA: DNA-recorded library synthesis, in which encoding and library synthesis take place separately, and DNA-directed library synthesis, in which DNA both encodes and templates library synthesis. We also describe in vitro selection methods used to evaluate DNA-encoded libraries and summarize successful applications of these approaches to the discovery of bioactive small molecules and novel chemical reactivity.

  17. Methods to enable the design of bioactive small molecules targeting RNA (United States)

    Disney, Matthew D.; Yildirim, Ilyas; Childs-Disney, Jessica L.


    RNA is an immensely important target for small molecule therapeutics or chemical probes of function. However, methods that identify, annotate, and optimize RNA-small molecule interactions that could enable the design of compounds that modulate RNA function are in their infancies. This review describes recent approaches that have been developed to understand and optimize RNA motif-small molecule interactions, including Structure-Activity Relationships Through Sequencing (StARTS), quantitative structure-activity relationships (QSAR), chemical similarity searching, structure-based design and docking, and molecular dynamics (MD) simulations. Case studies described include the design of small molecules targeting RNA expansions, the bacterial A-site, viral RNAs, and telomerase RNA. These approaches can be combined to afford a synergistic method to exploit the myriad of RNA targets in the transcriptome. PMID:24357181

  18. Color-Coded Super-Resolution Small-Molecule Imaging. (United States)

    Beuzer, Paolo; La Clair, James J; Cang, Hu


    Although the development of super-resolution microscopy dates back to 1994, its applications have been primarily focused on visualizing cellular structures and targets, including proteins, DNA and sugars. We now report on a system that allows both monitoring of the localization of exogenous small molecules in live cells at low resolution and subsequent super-resolution imaging by using stochastic optical reconstruction microscopy (STORM) on fixed cells. This represents a powerful new tool to understand the dynamics of subcellular trafficking associated with the mode and mechanism of action of exogenous small molecules.

  19. Small molecule screen for candidate antimalarials targeting Plasmodium Kinesin-5. (United States)

    Liu, Liqiong; Richard, Jessica; Kim, Sunyoung; Wojcik, Edward J


    Plasmodium falciparum and vivax are responsible for the majority of malaria infections worldwide, resulting in over a million deaths annually. Malaria parasites now show measured resistance to all currently utilized drugs. Novel antimalarial drugs are urgently needed. The Plasmodium Kinesin-5 mechanoenzyme is a suitable "next generation" target. Discovered via small molecule screen experiments, the human Kinesin-5 has multiple allosteric sites that are "druggable." One site in particular, unique in its sequence divergence across all homologs in the superfamily and even within the same family, exhibits exquisite drug specificity. We propose that Plasmodium Kinesin-5 shares this allosteric site and likewise can be targeted to uncover inhibitors with high specificity. To test this idea, we performed a screen for inhibitors selective for Plasmodium Kinesin-5 ATPase activity in parallel with human Kinesin-5. Our screen of nearly 2000 compounds successfully identified compounds that selectively inhibit both P. vivax and falciparum Kinesin-5 motor domains but, as anticipated, do not impact human Kinesin-5 activity. Of note is a candidate drug that did not biochemically compete with the ATP substrate for the conserved active site or disrupt the microtubule-binding site. Together, our experiments identified MMV666693 as a selective allosteric inhibitor of Plasmodium Kinesin-5; this is the first identified protein target for the Medicines of Malaria Venture validated collection of parasite proliferation inhibitors. This work demonstrates that chemical screens against human kinesins are adaptable to homologs in disease organisms and, as such, extendable to strategies to combat infectious disease.

  20. Dissecting RNA-interference pathway with small molecules. (United States)

    Chiu, Ya-Lin; Dinesh, Chimmanamada U; Chu, Chia-ying; Ali, Akbar; Brown, Kirk M; Cao, Hong; Rana, Tariq M


    RNA interference (RNAi) is a process whereby short-interfering RNAs (siRNA) silence gene expression in a sequence-specific manner. We have screened a chemical library of substituted dihydropteridinones and identified a nontoxic, cell permeable, and reversible inhibitor of the RNAi pathway in human cells. Biochemical and fluorescence resonance-energy transfer experiments demonstrated that one of the compounds, named ATPA-18, inhibited siRNA unwinding that occurred within 6 hr of siRNA transfection. Extracts prepared from ATPA-18-treated cells also exhibited a decrease in target RNA cleavage by activated RNA-induced silencing complex (RISC*). Interestingly, when activated RISC*, which harbors unwound antisense siRNA, was treated with ATPA-18 in vitro, target RNA cleavage was not affected, indicating that this compound inhibited siRNA unwinding or steps upstream of unwinding in the RNAi pathway. Our results also establish the timing of siRNA unwinding and show that siRNA helicase activity is required for RNAi. ATPA-18 analogs will therefore provide a new class of small molecules for studying RNAi mechanisms in a variety of model organisms and deciphering in vivo genetic functions through reverse genetics.

  1. Gradient-Driven Molecule Construction: An Inverse Approach Applied to the Design of Small-Molecule Fixating Catalysts

    CERN Document Server

    Weymuth, Thomas


    Rational design of molecules and materials usually requires extensive screening of molecular structures for the desired property. The inverse approach to deduce a structure for a predefined property would be highly desirable, but is, unfortunately, not well-defined. However, feasible strategies for such an inverse design process may be successfully developed for specific purposes. We discuss options for calculating 'jacket' potentials that fulfill a predefined target requirement - a concept that we recently introduced [T. Weymuth, M. Reiher, MRS Proceediungs, 2013, 1524, DOI:10.1557/opl.2012.1764]. We consider the case of small-molecule activating transition metal catalysts. As a target requirement we choose the vanishing geometry gradients on all atoms of a subsystem consisting of a metal center binding the small molecule to be activated. The jacket potential can be represented within a full quantum model or by a sequence of approximations of which a field of electrostatic point charges is the simplest. In a...

  2. Phosphate binding energy and catalysis by small and large molecules. (United States)

    Morrow, Janet R; Amyes, Tina L; Richard, John P


    Catalysis is an important process in chemistry and enzymology. The rate acceleration for any catalyzed reaction is the difference between the activation barriers for the uncatalyzed (Delta G(HO)(#)) and catalyzed (Delta G(Me)(#)) reactions, which corresponds to the binding energy (Delta G(S)(#) = Delta G(Me)(#)-Delta G(HO)(#)) for transfer of the reaction transition state from solution to the catalyst. This transition state binding energy is a fundamental descriptor of catalyzed reactions, and its evaluation is necessary for an understanding of any and all catalytic processes. We have evaluated the transition state binding energies obtained from interactions between low molecular weight metal ion complexes or high molecular weight protein catalysts and the phosphate group of bound substrate. Work on catalysis by small molecules is exemplified by studies on the mechanism of action of Zn2(1)(H2O). A binding energy of Delta G(S)(#) = -9.6 kcal/mol was determined for Zn2(1)(H2O)-catalyzed cleavage of the RNA analogue HpPNP. The pH-rate profile for this cleavage reaction showed that there is optimal catalytic activity at high pH, where the catalyst is in the basic form [Zn2(1)(HO-)]. However, it was also shown that the active form of the catalyst is Zn2(1)(H2O) and that this recognizes the C2-oxygen-ionized substrate in the cleavage reaction. The active catalyst Zn2(1)(H2O) shows a high affinity for oxyphosphorane transition state dianions and a stable methyl phosphate transition state analogue, compared with the affinity for phosphate monoanion substrates. The transition state binding energies, Delta G(S)(#), for cleavage of HpPNP catalyzed by a variety of Zn2+ and Eu3+ metal ion complexes reflect the increase in the catalytic activity with increasing total positive charge at the catalyst. These values of Delta G(S)(#) are affected by interactions between the metal ion and its ligands, but these effects are small in comparison with Delta G(S)(#) observed for catalysis

  3. Interfacial processes in small molecule organic solar cells

    Institute of Scientific and Technical Information of China (English)


    This paper presents an overview of the recent progress of small molecule organic solar cells mainly based on the previous worksof our group. We will mainly focus on the interfacial processes in the cells. The dissociation of excitons at electrode/organic andorganic/organic interfaces can be directly observed by transient photovoltage measurements. A simple model including dissociationof excitons at the interface and drift of free carriers in the built-in field is proposed to explain the observed signals of transientphotovoltage. Besides exciton-blocking and preventing damage due to cathode evaporation,blocking permeation of oxygen and/orwater molecules and modulating the built-in field are proposed as functions of the buffer layer between C60 and Al. By the use ofthe inverted structure,a shelf lifetime of over 1500 h is achieved for unencapsulated small-molecule organic solar cells.

  4. Conformational analysis of small molecules: NMR and quantum mechanics calculations. (United States)

    Tormena, Cláudio F


    This review deals with conformational analysis in small organic molecules, and describes the stereoelectronic interactions responsible for conformational stability. Conformational analysis is usually performed using NMR spectroscopy through measurement of coupling constants at room or low temperature in different solvents to determine the populations of conformers in solution. Quantum mechanical calculations are used to address the interactions responsible for conformer stability. The conformational analysis of a large number of small molecules is described, using coupling constant measurements in different solvents and at low temperature, as well as recent applications of through-space and through-hydrogen bond coupling constants JFH as tools for the conformational analysis of fluorinated molecules. Besides NMR parameters, stereoelectronic interactions such as conjugative, hyperconjugative, steric and intramolecular hydrogen bond interactions involved in conformational preferences are discussed.

  5. Design of a small molecule against an oncogenic noncoding RNA. (United States)

    Velagapudi, Sai Pradeep; Cameron, Michael D; Haga, Christopher L; Rosenberg, Laura H; Lafitte, Marie; Duckett, Derek R; Phinney, Donald G; Disney, Matthew D


    The design of precision, preclinical therapeutics from sequence is difficult, but advances in this area, particularly those focused on rational design, could quickly transform the sequence of disease-causing gene products into lead modalities. Herein, we describe the use of Inforna, a computational approach that enables the rational design of small molecules targeting RNA to quickly provide a potent modulator of oncogenic microRNA-96 (miR-96). We mined the secondary structure of primary microRNA-96 (pri-miR-96) hairpin precursor against a database of RNA motif-small molecule interactions, which identified modules that bound RNA motifs nearby and in the Drosha processing site. Precise linking of these modules together provided Targaprimir-96 (3), which selectively modulates miR-96 production in cancer cells and triggers apoptosis. Importantly, the compound is ineffective on healthy breast cells, and exogenous overexpression of pri-miR-96 reduced compound potency in breast cancer cells. Chemical Cross-Linking and Isolation by Pull-Down (Chem-CLIP), a small-molecule RNA target validation approach, shows that 3 directly engages pri-miR-96 in breast cancer cells. In vivo, 3 has a favorable pharmacokinetic profile and decreases tumor burden in a mouse model of triple-negative breast cancer. Thus, rational design can quickly produce precision, in vivo bioactive lead small molecules against hard-to-treat cancers by targeting oncogenic noncoding RNAs, advancing a disease-to-gene-to-drug paradigm.

  6. Toward inkjet printing of small molecule organic light emitting diodes

    NARCIS (Netherlands)

    Gorter, H.; Coenen, M.J.J.; Slaats, M.W.L.; Ren, M.; Lu, W.; Kuijpers, C.J.; Groen, W.A.


    Thermal evaporation is the current standard for the manufacture of small molecule organic light emitting diodes (smOLEDs), but it requires vacuum process, complicated shadow masks and is inefficient in material utilization, resulting in high cost of ownership. As an alternative, wet solution deposit

  7. Predicting where small molecules bind at protein-protein interfaces.

    Directory of Open Access Journals (Sweden)

    Peter Walter

    Full Text Available Small molecules that bind at protein-protein interfaces may either block or stabilize protein-protein interactions in cells. Thus, some of these binding interfaces may turn into prospective targets for drug design. Here, we collected 175 pairs of protein-protein (PP complexes and protein-ligand (PL complexes with known three-dimensional structures for which (1 one protein from the PP complex shares at least 40% sequence identity with the protein from the PL complex, and (2 the interface regions of these proteins overlap at least partially with each other. We found that those residues of the interfaces that may bind the other protein as well as the small molecule are evolutionary more conserved on average, have a higher tendency of being located in pockets and expose a smaller fraction of their surface area to the solvent than the remaining protein-protein interface region. Based on these findings we derived a statistical classifier that predicts patches at binding interfaces that have a higher tendency to bind small molecules. We applied this new prediction method to more than 10,000 interfaces from the protein data bank. For several complexes related to apoptosis the predicted binding patches were in direct contact to co-crystallized small molecules.

  8. Caenorhabditis elegans chemical biology: lessons from small molecules (United States)

    How can we complement Caenorhabditis elegans genomics and proteomics with a comprehensive structural and functional annotation of its metabolome? Several lines of evidence indicate that small molecules of largely undetermined structure play important roles in C. elegans biology, including key pathw...

  9. NMR structural studies of protein-small molecule interactions

    NARCIS (Netherlands)

    Shah, Dipen M.


    The research presented in the thesis describes the development and implementation of solution based NMR methods that provide 3D structural information on the protein-small molecule complexes. These methods can be critical for structure based drug design and can be readily applied in the early stages

  10. Antidiabetic effects of glucokinase regulatory protein small-molecule disruptors (United States)

    Lloyd, David J.; St Jean, David J.; Kurzeja, Robert J. M.; Wahl, Robert C.; Michelsen, Klaus; Cupples, Rod; Chen, Michelle; Wu, John; Sivits, Glenn; Helmering, Joan; Komorowski, Renée; Ashton, Kate S.; Pennington, Lewis D.; Fotsch, Christopher; Vazir, Mukta; Chen, Kui; Chmait, Samer; Zhang, Jiandong; Liu, Longbin; Norman, Mark H.; Andrews, Kristin L.; Bartberger, Michael D.; van, Gwyneth; Galbreath, Elizabeth J.; Vonderfecht, Steven L.; Wang, Minghan; Jordan, Steven R.; Véniant, Murielle M.; Hale, Clarence


    Glucose homeostasis is a vital and complex process, and its disruption can cause hyperglycaemia and type II diabetes mellitus. Glucokinase (GK), a key enzyme that regulates glucose homeostasis, converts glucose to glucose-6-phosphate in pancreatic β-cells, liver hepatocytes, specific hypothalamic neurons, and gut enterocytes. In hepatocytes, GK regulates glucose uptake and glycogen synthesis, suppresses glucose production, and is subject to the endogenous inhibitor GK regulatory protein (GKRP). During fasting, GKRP binds, inactivates and sequesters GK in the nucleus, which removes GK from the gluconeogenic process and prevents a futile cycle of glucose phosphorylation. Compounds that directly hyperactivate GK (GK activators) lower blood glucose levels and are being evaluated clinically as potential therapeutics for the treatment of type II diabetes mellitus. However, initial reports indicate that an increased risk of hypoglycaemia is associated with some GK activators. To mitigate the risk of hypoglycaemia, we sought to increase GK activity by blocking GKRP. Here we describe the identification of two potent small-molecule GK-GKRP disruptors (AMG-1694 and AMG-3969) that normalized blood glucose levels in several rodent models of diabetes. These compounds potently reversed the inhibitory effect of GKRP on GK activity and promoted GK translocation both in vitro (isolated hepatocytes) and in vivo (liver). A co-crystal structure of full-length human GKRP in complex with AMG-1694 revealed a previously unknown binding pocket in GKRP distinct from that of the phosphofructose-binding site. Furthermore, with AMG-1694 and AMG-3969 (but not GK activators), blood glucose lowering was restricted to diabetic and not normoglycaemic animals. These findings exploit a new cellular mechanism for lowering blood glucose levels with reduced potential for hypoglycaemic risk in patients with type II diabetes mellitus.

  11. Small organic molecules modulating iodine uptake in thyroid

    Energy Technology Data Exchange (ETDEWEB)

    Ambroise, Y. [CEA Saclay, DSV/DBJC/SMMCB, 91 - Gif-sur-Yvette (France)


    The thyroid gland accumulates large quantities of iodine. This uptake is needed for the production of iodinated hormones (T3 and T4). The first step in the iodine accumulation is a basolateral transport of iodide ions by the cloned 'Natrium Iodide Sym-porter' also called NIS. Using high-throughput screening techniques, we have identified a series of inhibitors of the iodide uptake in thyrocytes. These compounds are of medical significance in case of thyroid deregulation and can also offer solutions for radio-iodine detoxification in case of emergency situations (nuclear industry...). In addition, these small organic molecules can be important tools for the understanding of NIS structure and functions In parallel, we have identified and characterized a single compound capable to strongly enhance the amount of intra-cellular iodide in rat thyrocytes (FRTL5) as well as in HEK293 cells transfected with hNIS (Natrium/Iodide Sym-porter). Preliminary studies show that this effect is NIS dependant, and is induced by alternative and unknown mechanisms. Future work will consist in unraveling the mode of action of this molecule. These informations will help us not only to better understand the iodide pathways in the thyroid, but also to design more active analogues. We will use photo-labelling techniques to identify new proteins involved in the iodide transfer and retention. In addition, preliminary experiments are underway to validate our compound as an anti-cancer agent. Targeted NIS gene delivery into tumors plus radio-iodide injection leads to tumor size regression. Unfortunately, doses of radioactivity are to high for safe treatment. Our compound may lead to enhanced radio-iodide entrapment, thus necessitating lower doses of radioactivity for tumor regression. (author)

  12. Comparative metabolomics and structural characterizations illuminate colibactin pathway-dependent small molecules. (United States)

    Vizcaino, Maria I; Engel, Philipp; Trautman, Eric; Crawford, Jason M


    The gene cluster responsible for synthesis of the unknown molecule "colibactin" has been identified in mutualistic and pathogenic Escherichia coli. The pathway endows its producer with a long-term persistence phenotype in the human bowel, a probiotic activity used in the treatment of ulcerative colitis, and a carcinogenic activity under host inflammatory conditions. To date, functional small molecules from this pathway have not been reported. Here we implemented a comparative metabolomics and targeted structural network analyses approach to identify a catalog of small molecules dependent on the colibactin pathway from the meningitis isolate E. coli IHE3034 and the probiotic E. coli Nissle 1917. The structures of 10 pathway-dependent small molecules are proposed based on structural characterizations and network relationships. The network will provide a roadmap for the structural and functional elucidation of a variety of other small molecules encoded by the pathway. From the characterized small molecule set, in vitro bacterial growth inhibitory and mammalian CNS receptor antagonist activities are presented.

  13. Intercalation of small hydrophobic molecules in lipid bilayers containing cholesterol

    Energy Technology Data Exchange (ETDEWEB)

    Worcester, D.L.; Hamacher, K.; Kaiser, H.; Kulasekere, R.; Torbet, J. [Univ. of Missouri, Columbia, MO (United States)


    Partitioning of small hydrophobic molecules into lipid bilayers containing cholesterol has been studied using the 2XC diffractometer at the University of Missouri Research Reactor. Locations of the compounds were determined by Fourier difference methods with data from both deuterated and undeuterated compounds introduced into the bilayers from the vapor phase. Data fitting procedures were developed for determining how well the compounds were localized. The compounds were found to be localized in a narrow region at the center of the hydrophobic layer, between the two halves of the bilayer. The structures are therefore intercalated structures with the long axis of the molecules in the plane of the bilayer.

  14. A new class of small molecule inhibitor of BMP signaling.

    Directory of Open Access Journals (Sweden)

    Caroline E Sanvitale

    Full Text Available Growth factor signaling pathways are tightly regulated by phosphorylation and include many important kinase targets of interest for drug discovery. Small molecule inhibitors of the bone morphogenetic protein (BMP receptor kinase ALK2 (ACVR1 are needed urgently to treat the progressively debilitating musculoskeletal disease fibrodysplasia ossificans progressiva (FOP. Dorsomorphin analogues, first identified in zebrafish, remain the only BMP inhibitor chemotype reported to date. By screening an assay panel of 250 recombinant human kinases we identified a highly selective 2-aminopyridine-based inhibitor K02288 with in vitro activity against ALK2 at low nanomolar concentrations similar to the current lead compound LDN-193189. K02288 specifically inhibited the BMP-induced Smad pathway without affecting TGF-β signaling and induced dorsalization of zebrafish embryos. Comparison of the crystal structures of ALK2 with K02288 and LDN-193189 revealed additional contacts in the K02288 complex affording improved shape complementarity and identified the exposed phenol group for further optimization of pharmacokinetics. The discovery of a new chemical series provides an independent pharmacological tool to investigate BMP signaling and offers multiple opportunities for pre-clinical development.

  15. Small-Molecule Inhibition of BRDT for Male Contraception (United States)

    Matzuk, Martin M.; McKeown, Michael R.; Filippakopoulos, Panagis; Li, Qinglei; Ma, Lang; Agno, Julio E.; Lemieux, Madeleine E.; Picaud, Sarah; Yu, Richard N.; Qi, Jun; Knapp, Stefan; Bradner, James E.


    Summary A pharmacologic approach to male contraception remains a longstanding challenge in medicine. Toward this objective, we explored the spermatogenic effects of a selective small-molecule inhibitor (JQ1) of the bromodomain and extraterminal (BET) subfamily of epigenetic reader proteins. Here, we report potent inhibition of the testis-specific member BRDT, which is essential for chromatin remodeling during spermatogenesis. Biochemical and crystallographic studies confirm that occupancy of the BRDT acetyl-lysine binding pocket by JQ1 prevents recognition of acetylated histone H4. Treatment of mice with JQ1 reduced seminiferous tubule area, testis size, and spermatozoa number and motility without affecting hormone levels. Although JQ1-treated males mate normally, inhibitory effects of JQ1 evident at the spermatocyte and round spermatid stages cause a complete and reversible contraceptive effect. These data establish a new contraceptive that can cross the blood:testis boundary and inhibit bromodomain activity during spermatogenesis, providing a lead compound targeting the male germ cell for contraception. PaperClip PMID:22901802

  16. Reaction dynamics of small molecules at metal surfaces

    CERN Document Server

    Samson, P A


    directed angular distributions suggest the influence of a trapping mechanism, recombining molecules scattering through a molecularly adsorbed state, with a transition state of large d sub N sub N responsible for the product vibrational excitation. Although N sub 2 dissociation on Fe(100) forms a simple overlayer structure, on Fe(110), molecular chemisorption does not occur at or above room temperature and the sticking is extremely small (approx 10 sup - sup 6 to 10 sup - sup 7). Activated nitrogen bombardment can be used to prepare a 'surface nitride' with a structure related to the geometry of bulk Fe sub 4 N. Scanning tunnelling microscopy yields atomic scale features that cannot be explained by simple overlayers. It is proposed that the uppermost iron layer reconstructs to generate quasi-octahedral sites between the top two layers, with sub-surface nitrogen in these sites forming a model for the 'surface nitride' structure. The dissociation-desorption dynamics of D sub 2 upon the Sn/Pt(111) surface alloy a...

  17. Small and Large Molecules in the Diffuse Interstellar Medium (United States)

    Oka, Takeshi; Huang, Jane


    Although molecules with a wide range of sizes exist in dense clouds (e.g. H(C≡C)_nC≡N with n = 0 - 5), molecules identified in diffuse clouds are all small ones. Since the initial discovery of CH, CN, and CH^+, all molecules detected in the optical region are diatomics except for H_3^+ in the infrared and C_3 in the visible. Radio observations have been limited up to triatomic molecules except for H_2CO and the ubiquitous C_3H_2. The column densities of all molecules are less than 1014 cm-2 with the two exceptions of CO and H_3^+ as well as CH and C_2 in a few special sightlines. Larger molecules with many carbon atoms have been searched for but have not been detected. On the other hand, the observations of a great many diffuse interstellar bands (380 toward HD 204827 and 414 toward HD 183143) with equivalent widths from 1 to 5700 m Å indicate high column densities of many heavy molecules. If an electronic transition dipole moment of 1 Debye is assumed, the observed equivalent widths translate to column densities from 5 × 1011 cm-2 to 3 × 1015 cm-2. It seems impossible that these large molecules are formed from chemical reactions in space from small molecules. It is more likely that they are fragments of aggregates, perhaps mixed aromatic/aliphatic organic nanoparticles (MAONS). MAONS and their large fragment molecules are stable against photodissociation in the diffuse ISM because the energy of absorbed photons is divided into statistical distributions of vibrational energy and emitted in the infrared rather than breaking a chemical bond. We use a simple Rice-Ramsperger-Kassel-Marcus theory to estimate the molecular size required for the stabilization. Snow, T. P. & McCall, B. J. 2006, ARA&A, 44 367 Hobbs, L. M., York, D. G., Snow, T. P., Oka, T., Thorburn, J. A., et al. 2008, ApJ, 680 1256 Hobbs, L. M., York, D. G., Thorburn, J. A., Snow, T. P., Bishof, M., et al. 2009, ApJ, 705 32 Kwok, S. & Zhang, S. 2013, ApJ, 771 5 Freed, K. F., Oka, T., & Suzuki, H

  18. Ultrafast charge redistribution in small iodine containing molecules

    CERN Document Server

    Hollstein, Maximilian; Gerken, Nils; Klumpp, Stephan; Palutke, Steffen; Baev, Ivan; Brenner, Günter; Dziarzhytski, Siarhei; Wurth, Wilfried; Pfannkuche, Daniela


    The competition between intra molecular charge redistribution and fragmentation has been studied in small molecules containing iodine by using intense ultrashort pulses in the extreme ultraviolet regime (XUV). We show that after an element specific inner-shell photoionization of diiodomethane (CH$_2$I$_2$) and iodomethane (CH$_3$I), the induced positive charge is redistributed with a significantly different efficiency. Therefore, we analyze ion time-of-flight data obtained from XUV-pump XUV-probe experiments at the Free Electron Laser in Hamburg (FLASH). Theoretical considerations on the basis of ab initio electronic structure calculations including correlations relate this effect to a strongly molecule specific, purely electronic charge redistribution process that takes place directly after photoionization causing a distribution of the induced positive charge predominantly on the atoms which exhibit the lowest atomic ionization potential, i.e, in the molecules considered, the iodine atom(s). As a result of t...

  19. Optically active quantum-dot molecules. (United States)

    Shlykov, Alexander I; Baimuratov, Anvar S; Baranov, Alexander V; Fedorov, Anatoly V; Rukhlenko, Ivan D


    Chiral molecules made of coupled achiral semiconductor nanocrystals, also known as quantum dots, show great promise for photonic applications owing to their prospective uses as configurable building blocks for optically active structures, materials, and devices. Here we present a simple model of optically active quantum-dot molecules, in which each of the quantum dots is assigned a dipole moment associated with the fundamental interband transition between the size-quantized states of its confined charge carriers. This model is used to analytically calculate the rotatory strengths of optical transitions occurring upon the excitation of chiral dimers, trimers, and tetramers of general configurations. The rotatory strengths of such quantum-dot molecules are found to exceed the typical rotatory strengths of chiral molecules by five to six orders of magnitude. We also study how the optical activity of quantum-dot molecules shows up in their circular dichroism spectra when the energy gap between the molecular states is much smaller than the states' lifetime, and maximize the strengths of the circular dichroism peaks by optimizing orientations of the quantum dots in the molecules. Our analytical results provide clear design guidelines for quantum-dot molecules and can prove useful in engineering optically active quantum-dot supercrystals and photonic devices.

  20. Carbon nanotubes for delivery of small molecule drugs. (United States)

    Wong, Bin Sheng; Yoong, Sia Lee; Jagusiak, Anna; Panczyk, Tomasz; Ho, Han Kiat; Ang, Wee Han; Pastorin, Giorgia


    In the realm of drug delivery, carbon nanotubes (CNTs) have gained tremendous attention as promising nanocarriers, owing to their distinct characteristics, such as high surface area, enhanced cellular uptake and the possibility to be easily conjugated with many therapeutics, including both small molecules and biologics, displaying superior efficacy, enhanced specificity and diminished side effects. While most CNT-based drug delivery system (DDS) had been engineered to combat cancers, there are also emerging reports that employ CNTs as either the main carrier or adjunct material for the delivery of various non-anticancer drugs. In this review, the delivery of small molecule drugs is expounded, with special attention paid to the current progress of in vitro and in vivo research involving CNT-based DDSs, before finally concluding with some consideration on inevitable complications that hamper successful disease intervention with CNTs.

  1. Enhanced Vibrational Spectroscopies as Tools for Small Molecule Biosensing

    Directory of Open Access Journals (Sweden)

    Souhir Boujday


    Full Text Available In this short summary we summarize some of the latest developments in vibrational spectroscopic tools applied for the sensing of (small molecules and biomolecules in a label-free mode of operation. We first introduce various concepts for the enhancement of InfraRed spectroscopic techniques, including the principles of Attenuated Total Reflection InfraRed (ATR-IR, (phase-modulated InfraRed Reflection Absorption Spectroscopy (IRRAS/PM-IRRAS, and Surface Enhanced Infrared Reflection Absorption Spectroscopy (SEIRAS. Particular attention is put on the use of novel nanostructured substrates that allow for the excitation of propagating and localized surface plasmon modes aimed at operating additional enhancement mechanisms. This is then be complemented by the description of the latest development in Surface- and Tip-Enhanced Raman Spectroscopies, again with an emphasis on the detection of small molecules or bioanalytes.

  2. Small molecule probes for plant cell wall polysaccharide imaging

    Directory of Open Access Journals (Sweden)

    Ian eWallace


    Full Text Available Plant cell walls are composed of interlinked polymer networks consisting of cellulose, hemicelluloses, pectins, proteins, and lignin. The ordered deposition of these components is a dynamic process that critically affects the development and differentiation of plant cells. However, our understanding of cell wall synthesis and remodeling, as well as the diverse cell wall architectures that result from these processes, has been limited by a lack of suitable chemical probes that are compatible with live-cell imaging. In this review, we summarize the currently available molecular toolbox of probes for cell wall polysaccharide imaging in plants, with particular emphasis on recent advances in small molecule-based fluorescent probes. We also discuss the potential for further development of small molecule probes for the analysis of cell wall architecture and dynamics.

  3. SCH529074, a small molecule activator of mutant p53, which binds p53 DNA binding domain (DBD), restores growth-suppressive function to mutant p53 and interrupts HDM2-mediated ubiquitination of wild type p53. (United States)

    Demma, Mark; Maxwell, Eugene; Ramos, Robert; Liang, Lianzhu; Li, Cheng; Hesk, David; Rossman, Randall; Mallams, Alan; Doll, Ronald; Liu, Ming; Seidel-Dugan, Cynthia; Bishop, W Robert; Dasmahapatra, Bimalendu


    Abrogation of p53 function occurs in almost all human cancers, with more than 50% of cancers harboring inactivating mutations in p53 itself. Mutation of p53 is indicative of highly aggressive cancers and poor prognosis. The vast majority of mutations in p53 occur in its core DNA binding domain (DBD) and result in inactivation of p53 by reducing its thermodynamic stability at physiological temperature. Here, we report a small molecule, SCH529074, that binds specifically to the p53 DBD in a saturable manner with an affinity of 1-2 microm. Binding restores wild type function to many oncogenic mutant forms of p53. This small molecule reactivates mutant p53 by acting as a chaperone, in a manner similar to that previously reported for the peptide CDB3. Binding of SCH529074 to the p53 DBD is specifically displaced by an oligonucleotide with a sequence derived from the p53-response element. In addition to reactivating mutant p53, SCH529074 binding inhibits ubiquitination of p53 by HDM2. We have also developed a novel variant of p53 by changing a single amino acid in the core domain of p53 (N268R), which abolishes binding of SCH529074. This amino acid change also inhibits HDM2-mediated ubiquitination of p53. Our novel findings indicate that through its interaction with p53 DBD, SCH529074 restores DNA binding activity to mutant p53 and inhibits HDM2-mediated ubiquitination.

  4. Polymer and small molecule based hybrid light source (United States)

    Choong, Vi-En; Choulis, Stelios; Krummacher, Benjamin Claus; Mathai, Mathew; So, Franky


    An organic electroluminescent device, includes: a substrate; a hole-injecting electrode (anode) coated over the substrate; a hole injection layer coated over the anode; a hole transporting layer coated over the hole injection layer; a polymer based light emitting layer, coated over the hole transporting layer; a small molecule based light emitting layer, thermally evaporated over the polymer based light emitting layer; and an electron-injecting electrode (cathode) deposited over the electroluminescent polymer layer.

  5. Analysis of Imprecision in Incurred Sample Reanalysis for Small Molecules


    Subramaniam, Sriram; Patel, Devvrat; Davit, Barbara M.; Conner, Dale P.


    Over the years, incurred sample (IS) reanalysis (ISR) has become a tool to confirm the reliability of bioanalytical measurements. The recommendation for ISR acceptance criterion for small molecules is at least 67% of ISR samples that have reanalyzed concentrations within 20% of their original concentrations when normalized to their means. To understand the relevance of the ISR acceptance criterion and sample size requirements, simulated ISR studies evaluated the probability of ISR studies pas...

  6. Biocatalysts and their small molecule products from metagenomic studies



    The vast majority of bacteria present in environmental samples have never been cultured and therefore they have not been available to exploit their ability to produce useful biocatalysts or collections of biocatalysts that can biosynthesize interesting small molecules. Metagenomic libraries constructed using DNA extracted directly from natural bacterial communities offer access to the genetic information present in the genomes of these as yet uncultured bacteria. This review highlights recent...

  7. Recent advances in small molecule OLED-on-silicon microdisplays (United States)

    Ghosh, Amalkumar P.; Ali, Tariq A.; Khayrullin, Ilyas; Vazan, Fridrich; Prache, Olivier F.; Wacyk, Ihor


    High resolution OLED-on-silicon microdisplay technology is unique and challenging since it requires very small subpixel dimensions (~ 2-5 microns). eMagin's OLED microdisplay is based on white top emitter architecture using small molecule organic materials. The devices are fabricated using high Tg materials. The devices are hermetically sealed with vacuum deposited thin film layers. LCD-type color filters are patterned using photolithography methods to generate primary R, G, B colors. Results of recent improvements in the OLED-on-silicon microdisplay technology, with emphasis on efficiencies, lifetimes, grey scale and CIE color coordinates for SVGA and SXGA resolution microdisplays is presented.

  8. Small-molecule inhibitors of dengue-virus entry.

    Directory of Open Access Journals (Sweden)

    Aaron G Schmidt

    Full Text Available Flavivirus envelope protein (E mediates membrane fusion and viral entry from endosomes. A low-pH induced, dimer-to-trimer rearrangement and reconfiguration of the membrane-proximal "stem" of the E ectodomain draw together the viral and cellular membranes. We found stem-derived peptides from dengue virus (DV bind stem-less E trimer and mimic the stem-reconfiguration step in the fusion pathway. We adapted this experiment as a high-throughput screen for small molecules that block peptide binding and thus may inhibit viral entry. A compound identified in this screen, 1662G07, and a number of its analogs reversibly inhibit DV infectivity. They do so by binding the prefusion, dimeric E on the virion surface, before adsorption to a cell. They also block viral fusion with liposomes. Structure-activity relationship studies have led to analogs with submicromolar IC₉₀s against DV2, and certain analogs are active against DV serotypes 1,2, and 4. The compounds do not inhibit the closely related Kunjin virus. We propose that they bind in a previously identified, E-protein pocket, exposed on the virion surface and although this pocket is closed in the postfusion trimer, its mouth is fully accessible. Examination of the E-trimer coordinates (PDB 1OK8 shows that conformational fluctuations around the hinge could open the pocket without dissociating the trimer or otherwise generating molecular collisions. We propose that compounds such as 1662G07 trap the sE trimer in a "pocket-open" state, which has lost affinity for the stem peptide and cannot support the final "zipping up" of the stem.

  9. Urea transporter proteins as targets for small-molecule diuretics (United States)

    Esteva-Font, Cristina; Anderson, Marc O.; Verkman, Alan S.


    Conventional diuretics such as furosemide and thiazides target salt transporters in kidney tubules, but urea transporters (UTs) have emerged as alternative targets. UTs are a family of transmembrane channels expressed in a variety of mammalian tissues, in particular the kidney. UT knockout mice and humans with UT mutations exhibit reduced maximal urinary osmolality, demonstrating that UTs are necessary for the concentration of urine. Small-molecule screening has identified potent and selective inhibitors of UT-A, the UT protein expressed in renal tubule epithelial cells, and UT-B, the UT protein expressed in vasa recta endothelial cells. Data from UT knockout mice and from rodents administered UT inhibitors support the diuretic action of UT inhibition. The kidney-specific expression of UT-A1, together with high selectivity of the small-molecule inhibitors, means that off-target effects of such small-molecule drugs should be minimal. This Review summarizes the structure, expression and function of UTs, and looks at the evidence supporting the validity of UTs as targets for the development of salt-sparing diuretics with a unique mechanism of action. UT-targeted inhibitors may be useful alone or in combination with conventional diuretics for therapy of various oedemas and hyponatraemias, potentially including those refractory to treatment with current diuretics. PMID:25488859

  10. Reprogramming with Small Molecules instead of Exogenous Transcription Factors

    Directory of Open Access Journals (Sweden)

    Tongxiang Lin


    Full Text Available Induced pluripotent stem cells (iPSCs could be employed in the creation of patient-specific stem cells, which could subsequently be used in various basic and clinical applications. However, current iPSC methodologies present significant hidden risks with respect to genetic mutations and abnormal expression which are a barrier in realizing the full potential of iPSCs. A chemical approach is thought to be a promising strategy for safety and efficiency of iPSC generation. Many small molecules have been identified that can be used in place of exogenous transcription factors and significantly improve iPSC reprogramming efficiency and quality. Recent studies have shown that the use of small molecules results in the generation of chemically induced pluripotent stem cells from mouse embryonic fibroblast cells. These studies might lead to new areas of stem cell research and medical applications, not only human iPSC by chemicals alone, but also safe generation of somatic stem cells for cell based clinical trials and other researches. In this paper, we have reviewed the recent advances in small molecule approaches for the generation of iPSCs.

  11. In vitro and in vivo activity of novel small-molecule inhibitors targeting the pleckstrin homology domain of protein kinase B/AKT. (United States)

    Moses, Sylvestor A; Ali, M Ahad; Zuohe, Song; Du-Cuny, Lei; Zhou, Li Li; Lemos, Robert; Ihle, Nathan; Skillman, A Geoffrey; Zhang, Shuxing; Mash, Eugene A; Powis, Garth; Meuillet, Emmanuelle J


    The phosphatidylinositol 3-kinase/AKT signaling pathway plays a critical role in activating survival and antiapoptotic pathways within cancer cells. Several studies have shown that this pathway is constitutively activated in many different cancer types. The goal of this study was to discover novel compounds that bind to the pleckstrin homology (PH) domain of AKT, thereby inhibiting AKT activation. Using proprietary docking software, 22 potential PH domain inhibitors were identified. Surface plasmon resonance spectroscopy was used to measure the binding of the compounds to the expressed PH domain of AKT followed by an in vitro activity screen in Panc-1 and MiaPaCa-2 pancreatic cancer cell lines. We identified a novel chemical scaffold in several of the compounds that binds selectively to the PH domain of AKT, inducing a decrease in AKT activation and causing apoptosis at low micromolar concentrations. Structural modifications of the scaffold led to compounds with enhanced inhibitory activity in cells. One compound, 4-dodecyl-N-(1,3,4-thiadiazol-2-yl)benzenesulfonamide, inhibited AKT and its downstream targets in cells as well as in pancreatic cancer cell xenografts in immunocompromised mice; it also exhibited good antitumor activity. In summary, a pharmacophore for PH domain inhibitors targeting AKT function was developed. Computer-aided modeling, synthesis, and testing produced novel AKT PH domain inhibitors that exhibit promising preclinical properties.

  12. Small molecule screening at Helmholtz Zentrum München - from biology to molecules. (United States)

    Schorpp, Kenji; Hadian, Kamyar


    Within the last few years the Helmholtz Zentrum München has established several initiatives enabling the translation of basic research results into discovery of novel small molecules that affect pathomechanisms of chronic and complex diseases. Here, one of the main operations is the Assay Development and Screening Platform (ADSP) that has state-of-the-art equipment for compound screening and provides knowledge in a variety of biochemical or cell-based phenotypic assays. In particular, ADSP has a strong focus on complex assays such as high-content screening in stem cells that are likely to provide an innovative approach complementary to biochemical assays for the discovery of novel small molecules modulating key biological processes.

  13. A GPBAR1 (TGR5 small molecule agonist shows specific inhibitory effects on myeloid cell activation in vitro and reduces experimental autoimmune encephalitis (EAE in vivo.

    Directory of Open Access Journals (Sweden)

    Nuruddeen D Lewis

    Full Text Available GPBAR1 is a G protein-coupled receptor that is activated by certain bile acids and plays an important role in the regulation of bile acid synthesis, lipid metabolism, and energy homeostasis. Recent evidence suggests that GPBAR1 may also have important effects in reducing the inflammatory response through its expression on monocytes and macrophages. To further understand the role of GPBAR1 in inflammation, we generated a novel, selective, proprietary GPBAR1 agonist and tested its effectiveness at reducing monocyte and macrophage activation in vitro and in vivo. We have used this agonist, together with previously described agonists to study agonism of GPBAR1, and shown that they can all induce cAMP and reduce TLR activation-induced cytokine production in human monocytes and monocyte-derived macrophages in vitro. Additionally, through the usage of RNA sequencing (RNA-Seq, we identified a select set of genes that are regulated by GPBAR1 agonism during LPS activation. To further define the in vivo role of GPBAR1 in inflammation, we assessed GPBAR1 expression and found high levels on circulating mouse monocytes. Agonism of GPBAR1 reduced LPS-induced cytokine production in mouse monocytes ex vivo and serum cytokine levels in vivo. Agonism of GPBAR1 also had profound effects in the experimental autoimmune encephalomyelitis (EAE mouse model of multiple sclerosis, where monocytes play an important role. Mice treated with the GPBAR1 agonist exhibited a significant reduction in the EAE clinical score which correlated with reduced monocyte and microglial activation and reduced trafficking of monocytes and T cells into the CNS. These data confirm the importance of GPBAR1 in controlling monocyte and macrophage activation in vivo and support the rationale for selective agonists of GPBAR1 in the treatment of inflammatory diseases.

  14. Structure-property relationships: asymmetric alkylphenyl-substituted anthracene molecules for use in small-molecule solar cells. (United States)

    Kim, Yu Jin; Ahn, Eun Soo; Jang, Sang Hun; An, Tae Kyu; Kwon, Soon-Ki; Chung, Dae Sung; Kim, Yun-Hi; Park, Chan Eon


    Two asymmetric anthracene-based organic molecules, NDHPEA and TNDHPEA, were prepared without or with a thiophene spacer between the anthracene and naphthalene units. These asymmetric oligomers displayed different degrees of coplanarity, as evidenced by differences in the dihedral angles calculated by using DFT. Differential scanning calorimetry and XRD studies were used to probe the crystallization characteristics and molecular packing structures in the active layers. The coplanarity of the molecules in the asymmetric structure significantly affected the crystallization behavior and the formation of crystalline domains in the solid state. The small-molecule crystalline properties were correlated with the device physics by determining the J-V characteristics and hole mobilities of the devices.

  15. Antitumor Activity of a 5-Hydroxy-1H-Pyrrol-2-(5H-One-Based Synthetic Small Molecule In Vitro and In Vivo.

    Directory of Open Access Journals (Sweden)

    Yunyun Geng

    Full Text Available Alternative chemo-reagents are in great demand because chemotherapy resistance is one of the major challenges in current cancer treatment. 5-hydoxy-1H-pyrrol-2-(5H-one is an important N-heterocyclic scaffold that is present in natural products and medicinal chemistry. However, its antitumor activity has not been systematically explored. In this study, we screened a panel of 5-hydoxy-1H-pyrrol-2-(5H-one derivatives and identified compound 1d as possessing strong anti-proliferative activity in multiple cancer cell lines. Cell cycle analysis revealed that 1d can induce S-phase cell cycle arrest and that HCT116 was sensitive to 1d-induced apoptosis. Further analysis indicated that 1d preferentially induced DNA damage and p53 activation in HCT116 cells and that 1d-induced apoptosis is partly dependent on p53. Furthermore, we showed that 1d significantly suppressed tumor growth in xenograft tumor models in vivo. Taken together, our results suggest that 5-hydoxy-1H-pyrrol-2-(5H-one derivatives bear potential antitumor activity and that 1d is an effective agent for cancer treatment.

  16. Signal-amplification detection of small molecules by use of Mg2+-dependent DNAzyme. (United States)

    Guo, Zhijun; Wang, Jiahai; Wang, Erkang


    Because small molecules can be beneficial or toxic in biology and the environment, specific and sensitive detection of small molecules is one of the most important objectives of the scientific community. In this study, new signal amplification assays for detection of small molecules based on Mg(2+)-dependent DNAzyme were developed. A cleavable DNA substrate containing a ribonucleotide, the ends of which were labeled with black hole quencher (BHQ) and 6-carboxyfluorescein (FAM), was used for fluorescence detection. When the small molecule of interest is added to the assay solution, the Mg(2+)-dependent DNAzyme is activated, facilitating hybridization between the Mg(2+)-dependent DNAzyme and the DNA substrate. Binding of the substrate to the DNAzyme structure results in hydrolytic cleavage of the substrate in the presence of Mg(2+) ions. The fluorescence signal was amplified by continuous cleavage of the enzyme substrate. Ochratoxin A (OTA) and adenosine triphosphate (ATP) were used as model analytes in these experiments. This method can detect OTA specifically with a detection limit as low as 140 pmol L(-1) and detect ATP specifically with a detection limit as low as 13 nmol L(-1). Moreover, this method is potentially extendable to detection of other small molecules which are able to dissociate the aptamer from the DNAzyme, leading to activation of the DNAzyme.

  17. Synthesis and Exploratory Catalysis of 3d Metals: Group-Transfer Reactions, and the Activation and Functionalization of Small Molecules Including Greenhouse Gases

    Energy Technology Data Exchange (ETDEWEB)

    Mindiola, Daniel J.


    Our work over the past three years has resulted in the development of electron rich and low-coordinate vanadium fragments, molecular nitrides of vanadium and parent imide systems of titanium, and the synthesis of phosphorus containing molecules of the 3d transition metal series. Likewise, with financial support from BES Division in DOE (DE-FG02-07ER15893), we now completed the full characterization of the first single molecular magnet (SMM) of Fe(III). We demonstrated that this monomeric form of Fe(III) has an unusual slow relaxation of the magnetization under zero applied field. To make matters more interesting, this system also undergoes a rare example of an intermediate to high-spin transition (an S = 3/2 to S = 5/2 transition). In 2010 we reported the synthesis of the first neutral and low-coordinate vanadium complexes having the terminal nitride functionality. We have now completed a full study to understand formation of the nitride ligand from the metastable azide precursor, and have also explored the reactivity of the nitride ligand in the context of incomplete and complete N-atom transfer. During the 2010-2013 period we also discovered a facile approach to assemble low-coordinate and low-valent vanadium(II) complexes and exploit their multielectron chemistry ranging from 1-3 electrons. Consequently, we can now access 3d ligand frameworks such as cyclo-P3 (and its corresponding radical anion), nitride radical anions and cations, low-coordinate vanadium oxo’s, and the first example of a vanadium thionitrosyl complex. A cis-divacant iron(IV) imido having some ligand centered radical has been also discovered, and we are in the process of elucidating its electronic structure (in particular the sign of zero field splitting and the origin of its magnitude), bonding and reactivity. We have also revisited some paramagnetic and classic metallocene compounds with S >1/2 ground states in order to understand their reactivity patterns and electronic structure. Lastly

  18. Efficient Isothermal Titration Calorimetry Technique Identifies Direct Interaction of Small Molecule Inhibitors with the Target Protein. (United States)

    Gal, Maayan; Bloch, Itai; Shechter, Nelia; Romanenko, Olga; Shir, Ofer M


    Protein-protein interactions (PPI) play a critical role in regulating many cellular processes. Finding novel PPI inhibitors that interfere with specific binding of two proteins is considered a great challenge, mainly due to the complexity involved in characterizing multi-molecular systems and limited understanding of the physical principles governing PPIs. Here we show that the combination of virtual screening techniques, which are capable of filtering a large library of potential small molecule inhibitors, and a unique secondary screening by isothermal titration calorimetry, a label-free method capable of observing direct interactions, is an efficient tool for finding such an inhibitor. In this study we applied this strategy in a search for a small molecule capable of interfering with the interaction of the tumor-suppressor p53 and the E3-ligase MDM2. We virtually screened a library of 15 million small molecules that were filtered to a final set of 80 virtual hits. Our in vitro experimental assay, designed to validate the activity of mixtures of compounds by isothermal titration calorimetry, was used to identify an active molecule against MDM2. At the end of the process the small molecule (4S,7R)-4-(4-chlorophenyl)-5-hydroxy-2,7-dimethyl-N-(6-methylpyridin-2-yl)-4,6,7,8 tetrahydrIoquinoline-3-carboxamide was found to bind MDM2 with a dissociation constant of ~2 µM. Following the identification of this single bioactive compound, spectroscopic measurements were used to further characterize the interaction of the small molecule with the target protein. 2D NMR spectroscopy was used to map the binding region of the small molecule, and fluorescence polarization measurement confirmed that it indeed competes with p53.

  19. NMS-P937, an orally available, specific small-molecule polo-like kinase 1 inhibitor with antitumor activity in solid and hematologic malignancies. (United States)

    Valsasina, Barbara; Beria, Italo; Alli, Cristina; Alzani, Rachele; Avanzi, Nilla; Ballinari, Dario; Cappella, Paolo; Caruso, Michele; Casolaro, Alessia; Ciavolella, Antonella; Cucchi, Ulisse; De Ponti, Anna; Felder, Eduard; Fiorentini, Francesco; Galvani, Arturo; Gianellini, Laura M; Giorgini, Maria L; Isacchi, Antonella; Lansen, Jaqueline; Pesenti, Enrico; Rizzi, Simona; Rocchetti, Maurizio; Sola, Francesco; Moll, Jürgen


    Polo-like kinase 1 (PLK1) is a serine/threonine protein kinase considered to be the master player of cell-cycle regulation during mitosis. It is indeed involved in centrosome maturation, bipolar spindle formation, chromosome separation, and cytokinesis. PLK1 is overexpressed in a variety of human tumors and its overexpression often correlates with poor prognosis. Although five different PLKs are described in humans, depletion or inhibition of kinase activity of PLK1 is sufficient to induce cell-cycle arrest and apoptosis in cancer cell lines and in xenograft tumor models. NMS-P937 is a novel, orally available PLK1-specific inhibitor. The compound shows high potency in proliferation assays having low nanomolar activity on a large number of cell lines, both from solid and hematologic tumors. NMS-P937 potently causes a mitotic cell-cycle arrest followed by apoptosis in cancer cell lines and inhibits xenograft tumor growth with clear PLK1-related mechanism of action at well-tolerated doses in mice after oral administration. In addition, NMS-P937 shows potential for combination in clinical settings with approved cytotoxic drugs, causing tumor regression in HT29 human colon adenocarcinoma xenografts upon combination with irinotecan and prolonged survival of animals in a disseminated model of acute myelogenous leukemia in combination with cytarabine. NMS-P937, with its favorable pharmacologic parameters, good oral bioavailability in rodent and nonrodent species, and proven antitumor activity in different preclinical models using a variety of dosing regimens, potentially provides a high degree of flexibility in dosing schedules and warrants investigation in clinical settings.

  20. Treatment with a Small Molecule Mutant IDH1 Inhibitor Suppresses Tumorigenic Activity and Decreases Production of the Oncometabolite 2-Hydroxyglutarate in Human Chondrosarcoma Cells.

    Directory of Open Access Journals (Sweden)

    Luyuan Li

    Full Text Available Chondrosarcomas are malignant bone tumors that produce cartilaginous matrix. Mutations in isocitrate dehydrogenase enzymes (IDH1/2 were recently described in several cancers including chondrosarcomas. The IDH1 inhibitor AGI-5198 abrogates the ability of mutant IDH1 to produce the oncometabolite D-2 hydroxyglutarate (D-2HG in gliomas. We sought to determine if treatment with AGI-5198 would similarly inhibit tumorigenic activity and D-2HG production in IDH1-mutant human chondrosarcoma cells. Two human chondrosarcoma cell lines, JJ012 and HT1080 with endogenous IDH1 mutations and a human chondrocyte cell line C28 with wild type IDH1 were employed in our study. Mutation analysis of IDH was performed by PCR-based DNA sequencing, and D-2HG was detected using tandem mass spectrometry. We confirmed that JJ012 and HT1080 harbor IDH1 R132G and R132C mutation, respectively, while C28 has no mutation. D-2HG was detectable in cell pellets and media of JJ012 and HT1080 cells, as well as plasma and urine from an IDH-mutant chondrosarcoma patient, which decreased after tumor resection. AGI-5198 treatment decreased D-2HG levels in JJ012 and HT1080 cells in a dose-dependent manner, and dramatically inhibited colony formation and migration, interrupted cell cycling, and induced apoptosis. In conclusion, our study demonstrates anti-tumor activity of a mutant IDH1 inhibitor in human chondrosarcoma cell lines, and suggests that D-2HG is a potential biomarker for IDH mutations in chondrosarcoma cells. Thus, clinical trials of mutant IDH inhibitors are warranted for patients with IDH-mutant chondrosarcomas.

  1. An autonomous chemically fuelled small-molecule motor (United States)

    Wilson, Miriam R.; Solà, Jordi; Carlone, Armando; Goldup, Stephen M.; Lebrasseur, Nathalie; Leigh, David A.


    Molecular machines are among the most complex of all functional molecules and lie at the heart of nearly every biological process. A number of synthetic small-molecule machines have been developed, including molecular muscles, synthesizers, pumps, walkers, transporters and light-driven and electrically driven rotary motors. However, although biological molecular motors are powered by chemical gradients or the hydrolysis of adenosine triphosphate (ATP), so far there are no synthetic small-molecule motors that can operate autonomously using chemical energy (that is, the components move with net directionality as long as a chemical fuel is present). Here we describe a system in which a small molecular ring (macrocycle) is continuously transported directionally around a cyclic molecular track when powered by irreversible reactions of a chemical fuel, 9-fluorenylmethoxycarbonyl chloride. Key to the design is that the rate of reaction of this fuel with reactive sites on the cyclic track is faster when the macrocycle is far from the reactive site than when it is near to it. We find that a bulky pyridine-based catalyst promotes carbonate-forming reactions that ratchet the displacement of the macrocycle away from the reactive sites on the track. Under reaction conditions where both attachment and cleavage of the 9-fluorenylmethoxycarbonyl groups occur through different processes, and the cleavage reaction occurs at a rate independent of macrocycle location, net directional rotation of the molecular motor continues for as long as unreacted fuel remains. We anticipate that autonomous chemically fuelled molecular motors will find application as engines in molecular nanotechnology.

  2. Raman Optical Activity Spectra for Large Molecules through Molecules-in-Molecules Fragment-Based Approach. (United States)

    Jovan Jose, K V; Raghavachari, Krishnan


    We present an efficient method for the calculation of the Raman optical activity (ROA) spectra for large molecules through the molecules-in-molecules (MIM) fragment-based method. The relevant higher energy derivatives from smaller fragments are used to build the property tensors of the parent molecule to enable the extension of the MIM method for evaluating ROA spectra (MIM-ROA). Two factors were found to be particularly important in yielding accurate results. First, the link-atom tensor components are projected back onto the corresponding host and supporting atoms through the Jacobian projection method, yielding a mathematically rigorous method. Second, the long-range interactions between fragments are taken into account by using a less computationally expensive lower level of theory. The performance of the MIM-ROA model is calibrated on the enantiomeric pairs of 10 carbohydrate benchmark molecules, with strong intramolecular interactions. The vibrational frequencies and ROA intensities are accurately reproduced relative to the full, unfragmented, results for these systems. In addition, the MIM-ROA method is employed to predict the ROA spectra of d-maltose, α-D-cyclodextrin, and cryptophane-A, yielding spectra in excellent agreement with experiment. The accuracy and performance of the benchmark systems validate the MIM-ROA model for exploring ROA spectra of large molecules.

  3. Novel targets and derived small molecule inhibitors in multiple myeloma. (United States)

    Podar, Klaus


    Recent research advances have defined a key role of the bone marrow (BM) in multiple myeloma (MM) pathogenesis thereby leading to new treatment paradigms, which aim to target both the tumor cell as well as its BM microenvironment. The incorporation of thalidomide, bortezomib, and lenalidomide into conventional cytotoxic and transplantation regimens in relapsed and refractory, but also in newly diagnosed MM has changed treatment options during the last decade. However, MM remains still incurable. Ongoing translational research aims to identify additional therapeutic targets and to design derived agents, predominantly small molecule inhibitors, with higher potency and less toxicity to further improve MM patient outcome and to overcome drug resistance.

  4. Spectra and dynamics of small molecules Alexander von Humboldt lectures

    CERN Document Server

    Field, Robert W


    These seven lectures are intended to serve as an introduction for beginning graduate students to the spectra of small molecules. The author succeeds in illustrating the concepts by using language and metaphors that capture and elegantly convey simple insights into dynamics that lie beyond archival molecular constants. The lectures can simultaneously be viewed as a collection of interlocking special topics that have fascinated the author and his students over the years. Though neither a textbook nor a scholarly monograph, the book provides an illuminating perspective that will benefit students and researchers alike.

  5. Spectroscopic and dynamical studies of highly energized small polyatomic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Field, R.W.; Silbey, R.J. [Massachusetts Institute of Technology, Cambridge (United States)


    The authors have initiated a program to perform spectroscopic and dynamic studies of small molecules. Large amplitude motions in excited acetylene were discussed along with plans to record the dispersed fluorescence (DF) and the stimulated emission pumping (SEP) spectra. SEP spectra were reported for the formyl radical. A Fourier transform spectrometer was discussed with respect to its ability to probe the structure of radicals. This instrument is capable of performing studies using various techniques such as magnetic rotation spectroscopy and sub-Doppler sideband-OODR Zeman (SOODRZ) spectroscopy.

  6. Novel Chemical Strategies for Labeling Small Molecule Ligands for Androgen, Progestin, and Peroxisome Proliferator-Activated Receptors for Imaging Prostate and Breast Cancer and the Heart

    Energy Technology Data Exchange (ETDEWEB)

    Katzenellenbogen, John, A.


    Summary of Progress The specific aims of this project can be summarized as follows: • Aim 1: Prepare and evaluate radiolabeled ligands for the peroxisome proliferator-activated receptor (PPAR), a new nuclear hormone receptor target for tumor imaging and hormone therapy. • Aim 2: Prepare steroids labeled with a cyclopentadienyl tricarbonyl technetium or rhenium unit. • Aim 3: Prepare and evaluate other organometallic systems of novel design as ligand mimics and halogenated ligands for nuclear hormone receptor-based tumor imaging. As is described in detail below, we made excellent progress on all three of these aims; the highlights of our progress are the following: • we have prepared the first fluorine-18 labeled analogs of ligands for the PPAR receptor and used these in tissue distribution studies in rats • we have developed three new methods for the synthesis of cyclopentadienyltricarbonyl rhenium and technetium (CpRe(CO)3 and CpTc(CO)3) systems and we have adapted these to the synthesis of steroids labeled with these metals, as well as ligands for other receptor systems • we have prepared a number of fluorine-18 labeled steroidal and non-steroidal androgens and measured their tissue distribution in rats • we have prepared iodine and bromine-labeled progestins with high progesterone receptor binding affinity • we have prepared inorganic metal tricarbonyl complexes and steroid receptor ligands in which the metal tricarbonyl unit is an integral part off the ligand core.

  7. Encoded library technology screening of hepatitis C virus NS4B yields a small-molecule compound series with in vitro replicon activity. (United States)

    Arico-Muendel, Christopher; Zhu, Zhengrong; Dickson, Hamilton; Parks, Derek; Keicher, Jesse; Deng, Jianghe; Aquilani, Leah; Coppo, Frank; Graybill, Todd; Lind, Kenneth; Peat, Andrew; Thomson, Michael


    To identify novel antivirals to the hepatitis C virus (HCV) NS4B protein, we utilized encoded library technology (ELT), which enables purified proteins not amenable to standard biochemical screening methods to be tested against large combinatorial libraries in a short period of time. We tested NS4B against several DNA-encoded combinatorial libraries (DEL) and identified a single DEL feature that was subsequently progressed to off-DNA synthesis. The most active of the initial synthesized compounds had 50% inhibitory concentrations (IC50s) of 50 to 130 nM in a NS4B radioligand binding assay and 300 to 500 nM in an HCV replicon assay. Chemical optimization yielded compounds with potencies as low as 20 nM in an HCV genotype 1b replicon assay, 500 nM against genotype 1a, and 5 μM against genotype 2a. Through testing against other genotypes and genotype 2a-1b chimeric replicons and from resistance passage using the genotype 1b replicon, we confirmed that these compounds were acting on the proposed first transmembrane region of NS4B. A single sequence change (F98L) was identified as responsible for resistance, and it was thought to largely explain the relative lack of potency of this series against genotype 2a. Unlike other published series that appear to interact with this region, we did not observe sensitivity to amino acid substitutions at positions 94 and 105. The discovery of this novel compound series highlights ELT as a valuable approach for identifying direct-acting antivirals to nonenzymatic targets.

  8. Design, synthesis and evaluation of small molecule reactive oxygen species generators as selective Mycobacterium tuberculosis inhibitors. (United States)

    Dharmaraja, Allimuthu T; Alvala, Mallika; Sriram, Dharmarajan; Yogeeswari, Perumal; Chakrapani, Harinath


    Here, we report 5-hydroxy-1,2,3,4,4a,9a-hexahydro-1,4-ethano-9,10-anthraquinone (13), a small molecule generating reactive oxygen species (ROS) in pH 7.4 buffer under ambient aerobic conditions that has selective and potent Mycobacterium tuberculosis growth inhibitory activity.

  9. Perspective: Accurate ro-vibrational calculations on small molecules

    CERN Document Server

    Tennyson, Jonathan


    In what has been described as the fourth age of Quantum Chemistry, variational nuclear motion programs are now routinely being used to obtain the vibration-rotation levels and corresponding wavefunctions of small molecules to the sort of high accuracy demanded by comparison with spectroscopy. In this perspective I will discuss the current state-of-the-art which, for example, shows that these calculations are increasingly competitive with measurements or, indeed, replacing them and thus becoming the primary source of data on key processes. To achieve this accuracy {\\it ab initio} requires consideration small effects, routinely ignored in standard calculations, such those due to quantum electrodynamics (QED). Variational calculations are being used to generate huge list of transitions which provide the input for models of radiative transport through hot atmospheres and to fill in or even replace measured transition intensities. Future prospects such as study of molecular states near dissociation, which can prov...

  10. Small-Molecule Inhibitors of the Type III Secretion System

    Directory of Open Access Journals (Sweden)

    Lingling Gu


    Full Text Available Drug-resistant pathogens have presented increasing challenges to the discovery and development of new antibacterial agents. The type III secretion system (T3SS, existing in bacterial chromosomes or plasmids, is one of the most complicated protein secretion systems. T3SSs of animal and plant pathogens possess many highly conserved main structural components comprised of about 20 proteins. Many Gram-negative bacteria carry T3SS as a major virulence determinant, and using the T3SS, the bacteria secrete and inject effector proteins into target host cells, triggering disease symptoms. Therefore, T3SS has emerged as an attractive target for antimicrobial therapeutics. In recent years, many T3SS-targeting small-molecule inhibitors have been discovered; these inhibitors prevent the bacteria from injecting effector proteins and from causing pathophysiology in host cells. Targeting the virulence of Gram-negative pathogens, rather than their survival, is an innovative and promising approach that may greatly reduce selection pressures on pathogens to develop drug-resistant mutations. This article summarizes recent progress in the search for promising small-molecule T3SS inhibitors that target the secretion and translocation of bacterial effector proteins.

  11. Biophysical methods in drug discovery from small molecule to pharmaceutical. (United States)

    Holdgate, Geoffrey; Geschwindner, Stefan; Breeze, Alex; Davies, Gareth; Colclough, Nicola; Temesi, David; Ward, Lara


    Biophysical methods have become established in many areas of drug discovery. Application of these methods was once restricted to a relatively small number of scientists using specialized, low throughput technologies and methods. Now, automated high-throughput instruments are to be found in a growing number of laboratories. Many biophysical methods are capable of measuring the equilibrium binding constants between pairs of molecules crucial for molecular recognition processes, encompassing protein-protein, protein-small molecule, and protein-nucleic acid interactions, and several can be used to measure the kinetic or thermodynamic components controlling these biological processes. For a full characterization of a binding process, determinations of stoichiometry, binding mode, and any conformational changes associated with such interactions are also required. The suite of biophysical methods that are now available represents a powerful toolbox of techniques which can effectively deliver this full characterization.The aim of this chapter is to provide the reader with an overview of the drug discovery process and how biophysical methods, such as surface plasmon resonance (SPR), isothermal titration calorimetry (ITC), nuclear magnetic resonance, mass spectrometry (MS), and thermal unfolding methods can answer specific questions in order to influence project progression and outcomes. The selection of these examples is based upon the experiences of the authors at AstraZeneca, and relevant approaches are highlighted where they have utility in a particular drug discovery scenario.

  12. Roles of small molecules in somatic cell reprogramming. (United States)

    Su, Jian-bin; Pei, Duan-qing; Qin, Bao-ming


    The Nobel Prize in Physiology and Medicine 2012 was awarded to Sir John B GURDON and Shinya YAMANAKA for their discovery that mature cells can be reprogrammed to become pluripotent. This event reaffirms the importance of research on cell fate plasticity and the technology progress in the stem cell field and regenerative medicine. Indeed, reprogramming technology has developed at a dazzling speed within the past 6 years, yet we are still at the early stages of understanding the mechanisms of cell fate identity. This is particularly true in the case of human induced pluripotent stem cells (iPSCs), which lack reliable standards in the evaluation of their fidelity and safety prior to their application. Along with the genetic approaches, small molecules nowadays become convenient tools for modulating endogenous protein functions and regulating key cellular processes, including the mesenchymal-to-epithelial transition, metabolism, signal transduction and epigenetics. Moreover, small molecules may affect not only the efficiency of clone formation but also the quality of the resulting cells. With increasing availability of such chemicals, we can better understand the biology of stems cells and further improve the technology of generation of stem cells.

  13. Roles of small molecules in somatic cell reprogramming

    Institute of Scientific and Technical Information of China (English)

    Jian-bin SU; Duan-qing PEI; Bao-ming QIN


    The Nobel Prize in Physiology and Medicine 2012 was awarded to Sir John B GURDON and Shinya YAMANAKA for their discovery that mature cells can be reprogrammed to become pluripotent.This event reaffirms the importance of research on cell fate plasticity and the technology progress in the stem cell field and regenerative medicine.Indeed,reprogramming technology has developed at a dazzling speed within the past 6 years,yet we are still at the early stages of understanding the mechanisms of cell fate identity.This is particularly true in the case of human induced pluripotent stem ceils (iPSCs),which lack reliable standards in the evaluation of their fidelity and safety prior to their application.Along with the genetic approaches,small molecules nowadays become convenient tools for modulating endogenous protein functions and regulating key cellular processes,including the mesenchymal-to-epithelial transition,metabolism,signal transduction and epigenetics.Moreover,small molecules may affect not only the efficiency of clone formation but also the quality of the resulting cells.With increasing availability of such chemicals,we can better understand the biology of stems cells and further improve the technology of generation of stem cells.

  14. Reprogramming the assembly of unmodified DNA with a small molecule (United States)

    Avakyan, Nicole; Greschner, Andrea A.; Aldaye, Faisal; Serpell, Christopher J.; Toader, Violeta; Petitjean, Anne; Sleiman, Hanadi F.


    The ability of DNA to store and encode information arises from base pairing of the four-letter nucleobase code to form a double helix. Expanding this DNA ‘alphabet’ by synthetic incorporation of new bases can introduce new functionalities and enable the formation of novel nucleic acid structures. However, reprogramming the self-assembly of existing nucleobases presents an alternative route to expand the structural space and functionality of nucleic acids. Here we report the discovery that a small molecule, cyanuric acid, with three thymine-like faces, reprogrammes the assembly of unmodified poly(adenine) (poly(A)) into stable, long and abundant fibres with a unique internal structure. Poly(A) DNA, RNA and peptide nucleic acid (PNA) all form these assemblies. Our studies are consistent with the association of adenine and cyanuric acid units into a hexameric rosette, which brings together poly(A) triplexes with a subsequent cooperative polymerization. Fundamentally, this study shows that small hydrogen-bonding molecules can be used to induce the assembly of nucleic acids in water, which leads to new structures from inexpensive and readily available materials.

  15. Molecular Responses to Small Regulating Molecules against Huanglongbing Disease. (United States)

    Martinelli, Federico; Dolan, David; Fileccia, Veronica; Reagan, Russell L; Phu, My; Spann, Timothy M; McCollum, Thomas G; Dandekar, Abhaya M


    Huanglongbing (HLB; citrus greening) is the most devastating disease of citrus worldwide. No cure is yet available for this disease and infected trees generally decline after several months. Disease management depends on early detection of symptoms and chemical control of insect vectors. In this work, different combinations of organic compounds were tested for the ability to modulate citrus molecular responses to HLB disease beneficially. Three small-molecule regulating compounds were tested: 1) L-arginine, 2) 6-benzyl-adenine combined with gibberellins, and 3) sucrose combined with atrazine. Each treatment contained K-phite mineral solution and was tested at two different concentrations. Two trials were conducted: one in the greenhouse and the other in the orchard. In the greenhouse study, responses of 42 key genes involved in sugar and starch metabolism, hormone-related pathways, biotic stress responses, and secondary metabolism in treated and untreated mature leaves were analyzed. TGA5 was significantly induced by arginine. Benzyladenine and gibberellins enhanced two important genes involved in biotic stress responses: WRKY54 and WRKY59. Sucrose combined with atrazine mainly upregulated key genes involved in carbohydrate metabolism such as sucrose-phosphate synthase, sucrose synthase, starch synthase, and α-amylase. Atrazine also affected expression of some key genes involved in systemic acquired resistance such as EDS1, TGA6, WRKY33, and MYC2. Several treatments upregulated HSP82, which might help protect protein folding and integrity. A subset of key genes was chosen as biomarkers for molecular responses to treatments under field conditions. GPT2 was downregulated by all small-molecule treatments. Arginine-induced genes involved in systemic acquired resistance included PR1, WRKY70, and EDS1. These molecular data encourage long-term application of treatments that combine these regulating molecules in field trials.

  16. Molecular Responses to Small Regulating Molecules against Huanglongbing Disease.

    Directory of Open Access Journals (Sweden)

    Federico Martinelli

    Full Text Available Huanglongbing (HLB; citrus greening is the most devastating disease of citrus worldwide. No cure is yet available for this disease and infected trees generally decline after several months. Disease management depends on early detection of symptoms and chemical control of insect vectors. In this work, different combinations of organic compounds were tested for the ability to modulate citrus molecular responses to HLB disease beneficially. Three small-molecule regulating compounds were tested: 1 L-arginine, 2 6-benzyl-adenine combined with gibberellins, and 3 sucrose combined with atrazine. Each treatment contained K-phite mineral solution and was tested at two different concentrations. Two trials were conducted: one in the greenhouse and the other in the orchard. In the greenhouse study, responses of 42 key genes involved in sugar and starch metabolism, hormone-related pathways, biotic stress responses, and secondary metabolism in treated and untreated mature leaves were analyzed. TGA5 was significantly induced by arginine. Benzyladenine and gibberellins enhanced two important genes involved in biotic stress responses: WRKY54 and WRKY59. Sucrose combined with atrazine mainly upregulated key genes involved in carbohydrate metabolism such as sucrose-phosphate synthase, sucrose synthase, starch synthase, and α-amylase. Atrazine also affected expression of some key genes involved in systemic acquired resistance such as EDS1, TGA6, WRKY33, and MYC2. Several treatments upregulated HSP82, which might help protect protein folding and integrity. A subset of key genes was chosen as biomarkers for molecular responses to treatments under field conditions. GPT2 was downregulated by all small-molecule treatments. Arginine-induced genes involved in systemic acquired resistance included PR1, WRKY70, and EDS1. These molecular data encourage long-term application of treatments that combine these regulating molecules in field trials.

  17. Molecular Responses to Small Regulating Molecules against Huanglongbing Disease (United States)

    Martinelli, Federico; Dolan, David; Fileccia, Veronica; Reagan, Russell L.; Phu, My; Spann, Timothy M.; McCollum, Thomas G.; Dandekar, Abhaya M.


    Huanglongbing (HLB; citrus greening) is the most devastating disease of citrus worldwide. No cure is yet available for this disease and infected trees generally decline after several months. Disease management depends on early detection of symptoms and chemical control of insect vectors. In this work, different combinations of organic compounds were tested for the ability to modulate citrus molecular responses to HLB disease beneficially. Three small-molecule regulating compounds were tested: 1) L-arginine, 2) 6-benzyl-adenine combined with gibberellins, and 3) sucrose combined with atrazine. Each treatment contained K-phite mineral solution and was tested at two different concentrations. Two trials were conducted: one in the greenhouse and the other in the orchard. In the greenhouse study, responses of 42 key genes involved in sugar and starch metabolism, hormone-related pathways, biotic stress responses, and secondary metabolism in treated and untreated mature leaves were analyzed. TGA5 was significantly induced by arginine. Benzyladenine and gibberellins enhanced two important genes involved in biotic stress responses: WRKY54 and WRKY59. Sucrose combined with atrazine mainly upregulated key genes involved in carbohydrate metabolism such as sucrose-phosphate synthase, sucrose synthase, starch synthase, and α-amylase. Atrazine also affected expression of some key genes involved in systemic acquired resistance such as EDS1, TGA6, WRKY33, and MYC2. Several treatments upregulated HSP82, which might help protect protein folding and integrity. A subset of key genes was chosen as biomarkers for molecular responses to treatments under field conditions. GPT2 was downregulated by all small-molecule treatments. Arginine-induced genes involved in systemic acquired resistance included PR1, WRKY70, and EDS1. These molecular data encourage long-term application of treatments that combine these regulating molecules in field trials. PMID:27459099

  18. Discovery & development of small molecule allosteric modulators of glycoprotein hormone receptors

    Directory of Open Access Journals (Sweden)

    Selvaraj G Nataraja


    Full Text Available Glycoprotein hormones, follicle-stimulating hormone (FSH, luteinizing hormone (LH, and thyroid stimulating hormone (TSH are heterodimeric proteins with a common subunit and hormone-specific subunit. These hormones are dominant regulators of reproduction and metabolic processes. Receptors for the glycoprotein hormones belong to the family of G-protein coupled receptors (GPCR. FSH receptor (FSHR and LH receptor (LHR are primarily expressed in somatic cells in ovary and testis to promote egg and sperm production in women & men respectively. TSH receptor (TSHR is expressed in thyroid cells and regulates the secretion of T3 & T4. Glycoprotein hormones bind to the large extracellular domain of the receptor and cause a conformational change in the receptor that leads to activation of more than one intracellular signaling pathway. Several small molecules have been described to activate/inhibit glycoprotein hormone receptors through allosteric sites of the receptor. Small molecule allosteric modulators have the potential to be administered orally to patients thus improving the convenience of treatment. It has been a challenge to develop a small molecule allosteric agonist for glycoprotein hormones that can mimic the agonistic effects of the large natural ligand to activate similar signaling pathways. However, in the past few years, there have been several promising reports describing distinct chemical series with improved potency in preclinical models. In parallel, proposal of new structural model for FSH receptor and in silico docking studies of small molecule ligands to glycoprotein hormone receptors provide a giant leap on the understanding of the mechanism of action of the natural ligands and new chemical entities on the receptors. This review will focus on the current status of small molecule allosteric modulators of glycoprotein hormone receptors, their effects on common signaling pathways in cells, their utility for clinical

  19. Nanoelectropulse-driven membrane perturbation and small molecule permeabilization

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    Sun Yinghua


    Full Text Available Abstract Background Nanosecond, megavolt-per-meter pulsed electric fields scramble membrane phospholipids, release intracellular calcium, and induce apoptosis. Flow cytometric and fluorescence microscopy evidence has associated phospholipid rearrangement directly with nanoelectropulse exposure and supports the hypothesis that the potential that develops across the lipid bilayer during an electric pulse drives phosphatidylserine (PS externalization. Results In this work we extend observations of cells exposed to electric pulses with 30 ns and 7 ns durations to still narrower pulse widths, and we find that even 3 ns pulses are sufficient to produce responses similar to those reported previously. We show here that in contrast to unipolar pulses, which perturb membrane phospholipid order, tracked with FM1-43 fluorescence, only at the anode side of the cell, bipolar pulses redistribute phospholipids at both the anode and cathode poles, consistent with migration of the anionic PS head group in the transmembrane field. In addition, we demonstrate that, as predicted by the membrane charging hypothesis, a train of shorter pulses requires higher fields to produce phospholipid scrambling comparable to that produced by a time-equivalent train of longer pulses (for a given applied field, 30, 4 ns pulses produce a weaker response than 4, 30 ns pulses. Finally, we show that influx of YO-PRO-1, a fluorescent dye used to detect early apoptosis and activation of the purinergic P2X7 receptor channels, is observed after exposure of Jurkat T lymphoblasts to sufficiently large numbers of pulses, suggesting that membrane poration occurs even with nanosecond pulses when the electric field is high enough. Propidium iodide entry, a traditional indicator of electroporation, occurs with even higher pulse counts. Conclusion Megavolt-per-meter electric pulses as short as 3 ns alter the structure of the plasma membrane and permeabilize the cell to small molecules. The dose

  20. Transcriptional analysis of antiviral small molecule therapeutics as agonists of the RLR pathway

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    R.R. Green


    Full Text Available The recognition of pathogen associated molecular patterns (PAMPs by pattern recognition receptors (PRR during viral infection initiates the induction of antiviral signaling pathways, including activation of the Interferon Regulator Factor 3 (IRF3. We identified small molecule compounds that activate IRF3 through MAVS, thereby inhibiting infection by viruses of the families Flaviviridae (West Nile virus, dengue virus and hepatitis C virus, Filoviridae (Ebola virus, Orthomyxoviridae (influenza A virus, Arenaviridae (Lassa virus and Paramyxoviridae (respiratory syncytial virus, Nipah virus (1. In this study, we tested a lead compound along with medicinal chemistry-derived analogs to compare the gene transcriptional profiles induced by these molecules to that of other known MAVS-dependent IRF3 agonists. Transcriptional analysis of these small molecules revealed the induction of specific antiviral genes and identified a novel module of host driven immune regulated genes that suppress infection of a range of RNA viruses. Microarray data can be found in Gene Expression Omnibus (GSE74047.

  1. Chasing the structures of small molecules in arbuscular mycorrhizal signaling. (United States)

    Bucher, Marcel; Wegmüller, Sarah; Drissner, David


    The arbuscular mycorrhiza (AM) is a symbiosis between most terrestrial plants and fungi of the ancient phylum Glomeromycota. AM improves the uptake of water and mineral nutrients, such as phosphorus (P) and nitrogen (N), of the host plant in exchange for photosynthetically fixed carbon. Successful colonization and a functional interaction between host plant and mycobiont are based upon exchange of signaling molecules at different stages of symbiosis development. Strigolactones, a novel class of plant hormones, are secreted by plant roots stimulating presymbiotic growth of AM fungi. Fungi release soluble signaling molecules, the enigmatic 'Myc factors', that activate early symbiotic root responses. Lysophosphatidylcholine is a lipophilic intraradical mycorrhizal signal triggering plant phosphate transporter gene expression late in AM development through a P-controlled transcriptional mechanism. This enables uptake of orthophosphate released from the AM fungus.

  2. Composite microsphere-functionalized scaffold for the controlled release of small molecules in tissue engineering

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    Laura Pandolfi


    Full Text Available Current tissue engineering strategies focus on restoring damaged tissue architectures using biologically active scaffolds. The ideal scaffold would mimic the extracellular matrix of any tissue of interest, promoting cell proliferation and de novo extracellular matrix deposition. A plethora of techniques have been evaluated to engineer scaffolds for the controlled and targeted release of bioactive molecules to provide a functional structure for tissue growth and remodeling, as well as enhance recruitment and proliferation of autologous cells within the implant. Recently, novel approaches using small molecules, instead of growth factors, have been exploited to regulate tissue regeneration. The use of small synthetic molecules could be very advantageous because of their stability, tunability, and low cost. Herein, we propose a chitosan–gelatin scaffold functionalized with composite microspheres consisting of mesoporous silicon microparticles and poly(dl-lactic-co-glycolic acid for the controlled release of sphingosine-1-phospate, a small molecule of interest. We characterized the platform with scanning electron microscopy, Fourier transform infrared spectroscopy, and confocal microscopy. Finally, the biocompatibility of this multiscale system was analyzed by culturing human mesenchymal stem cells onto the scaffold. The presented strategy establishes the basis of a versatile scaffold for the controlled release of small molecules and for culturing mesenchymal stem cells for regenerative medicine applications.

  3. Organic Semiconductor-Containing Supramolecules: Effect of Small Molecule Crystallization and Molecular Packing

    KAUST Repository

    Rancatore, Benjamin J.


    © 2016 American Chemical Society. Small molecules (SMs) with unique optical or electronic properties provide an opportunity to incorporate functionality into block copolymer (BCP)-based supramolecules. However, the assembly of supramolecules based on these highly crystalline molecules differs from their less crystalline counterparts. Here, two families of organic semiconductor SMs are investigated, where the composition of the crystalline core, the location (side- vs end-functionalization) of the alkyl solubilizing groups, and the constitution (branched vs linear) of the alkyl groups are varied. With these SMs, we present a systematic study of how the phase behavior of the SMs affects the overall assembly of these organic semiconductor-based supramolecules. The incorporation of SMs has a large effect on the interfacial curvature, the supramolecular periodicity, and the overall supramolecular morphology. The crystal packing of the SM within the supramolecule does not necessarily lead to the assembly of the comb block within the BCP microdomains, as is normally observed for alkyl-containing supramolecules. An unusual lamellar morphology with a wavy interface between the microdomains is observed due to changes in the packing structure of the small molecule within BCP microdomains. Since the supramolecular approach is modular and small molecules can be readily switched out, present studies provide useful guidance toward access supramolecular assemblies over several length scales using optically active and semiconducting small molecules.

  4. Small molecule semiconductors for high-efficiency organic photovoltaics. (United States)

    Lin, Yuze; Li, Yongfang; Zhan, Xiaowei


    Organic photovoltaic cells (OPVs) are a promising cost-effective alternative to silicon-based solar cells, and possess light-weight, low-cost, and flexibility advantages. Significant progress has been achieved in the development of novel photovoltaic materials and device structures in the last decade. Nowadays small molecular semiconductors for OPVs have attracted considerable attention, due to their advantages over their polymer counterparts, including well-defined molecular structure, definite molecular weight, and high purity without batch to batch variations. The highest power conversion efficiencies of OPVs based on small molecular donor/fullerene acceptors or polymeric donor/fullerene acceptors are up to 6.7% and 8.3%, respectively, and meanwhile nonfullerene acceptors have also exhibited some promising results. In this review we summarize the developments in small molecular donors, acceptors (fullerene derivatives and nonfullerene molecules), and donor-acceptor dyad systems for high-performance multilayer, bulk heterojunction, and single-component OPVs. We focus on correlations of molecular chemical structures with properties, such as absorption, energy levels, charge mobilities, and photovoltaic performances. This structure-property relationship analysis may guide rational structural design and evaluation of photovoltaic materials (253 references).

  5. The identification of GPR3 inverse agonist AF64394; the first small molecule inhibitor of GPR3 receptor function. (United States)

    Jensen, Thomas; Elster, Lisbeth; Nielsen, Søren Møller; Poda, Suresh Babu; Loechel, Frosty; Volbracht, Christiane; Klewe, Ib Vestergaard; David, Laurent; Watson, Stephen P


    The identification of the novel and selective GPR3 inverse agonist AF64394, the first small molecule inhibitor of GPR3 receptor function, is described. Structure activity relationships and syntheses based around AF64394 are reported.

  6. Comparison of small molecules and oligonucleotides that target a toxic, non-coding RNA. (United States)

    Costales, Matthew G; Rzuczek, Suzanne G; Disney, Matthew D


    Potential RNA targets for chemical probes and therapeutic modalities are pervasive in the transcriptome. Oligonucleotide-based therapeutics are commonly used to target RNA sequence. Small molecules are emerging as a modality to target RNA structures selectively, but their development is still in its infancy. In this work, we compare the activity of oligonucleotides and several classes of small molecules that target the non-coding r(CCUG) repeat expansion (r(CCUG)(exp)) that causes myotonic dystrophy type 2 (DM2), an incurable disease that is the second-most common cause of adult onset muscular dystrophy. Small molecule types investigated include monomers, dimers, and multivalent compounds synthesized on-site by using RNA-templated click chemistry. Oligonucleotides investigated include phosphorothioates that cleave their target and vivo-morpholinos that modulate target RNA activity via binding. We show that compounds assembled on-site that recognize structure have the highest potencies amongst small molecules and are similar in potency to a vivo-morpholino modified oligonucleotide that targets sequence. These studies are likely to impact the design of therapeutic modalities targeting other repeats expansions that cause fragile X syndrome and amyotrophic lateral sclerosis, for example.

  7. Branched terthiophenes in organic electronics: from small molecules to polymers. (United States)

    Scheuble, Martin; Goll, Miriam; Ludwigs, Sabine


    A zoo of chemical structures is accessible when the branched unit 2,2':3',2″-terthiophene (3T) is included both in structurally well-defined small molecules and polymer-like architectures. The first part of this review article highlights literature on all-thiophene based branched oligomers including dendrimers as well as combinations of 3T-units with functional moieties for light-harvesting systems. Motivated by the perfectly branched macromolecular dendrimers both electropolymerization as well as chemical approaches are presented as methods for the preparation of branched polythiophenes with different branching densities. Structure-function relationships between the molecular architecture and optical and electronic properties are discussed throughout the article.

  8. Regulatory aspects of small molecule drugs for heart regeneration. (United States)

    Rodgers, Kathleen; Papinska, Anna; Mordwinkin, Nicholas


    Even though recent discoveries prove the existence of cardiac progenitor cells, internal regenerative capacity of the heart is minimal. As cardiovascular disease is the leading cause of deaths in the United States, a number of approaches are being used to develop treatments for heart repair and regeneration. Small molecule drugs are of particular interest as they are suited for oral administration and can be chemically synthesized. However, the regulatory process for the development of new treatment modalities is protracted, complex and expensive. One of the hurdles to development of appropriate therapies is the need for predictive preclinical models. The use of patient-derived cardiomyocytes from iPSC cells represents a novel tool for this purpose. Among other concepts for induction of heart regeneration, the most advanced is the combination of DPP-IV inhibitors with stem cell mobilizers. This review will focus on regulatory aspects as well as preclinical hurdles of development of new treatments for heart regeneration.

  9. Coacervate delivery systems for proteins and small molecule drugs. (United States)

    Johnson, Noah R; Wang, Yadong


    Coacervates represent an exciting new class of drug delivery vehicles, developed in the past decade as carriers of small molecule drugs and proteins. This review summarizes several well-described coacervate systems, including: i) elastin-like peptides for delivery of anticancer therapeutics; ii) heparin-based coacervates with synthetic polycations for controlled growth factor delivery; iii) carboxymethyl chitosan aggregates for oral drug delivery; iv) Mussel adhesive protein and hyaluronic acid coacervates. Coacervates present advantages in their simple assembly and easy incorporation into tissue engineering scaffolds or as adjuncts to cell therapies. They are also amenable to functionalization such as for targeting or for enhancing the bioactivity of their cargo. These new drug carriers are anticipated to have broad applications and noteworthy impact in the near future.

  10. Measurement of small molecule diffusion with an optofluidic silicon chip. (United States)

    Ryckeboer, Eva; Vierendeels, Jan; Lee, Agnes; Werquin, Sam; Bienstman, Peter; Baets, Roel


    In this work we explore the micro-ring resonator platform to study the diffusion-driven mass transport of small molecules within microfluidic channels. The micro-ring resonators are integrated on a silicon-on-insulator photonic chip and combined with microfluidics in poly(dimethylsiloxane) (PDMS). We apply a strong initial gradient in the solute concentration and use the micro-ring resonators to observe how this concentration evolves over time and space. This can be achieved by tracking the optical resonances of multiple micro-rings as they shift with changing solute concentration. Experiments are performed for both glucose and NaCl and at different temperatures. The measured concentration profiles are used to calculate the diffusion coefficient of both glucose and NaCl in water. The good agreement between measurement and theoretical prediction demonstrates the relevance of this method.

  11. Catalytic in vivo protein knockdown by small-molecule PROTACs. (United States)

    Bondeson, Daniel P; Mares, Alina; Smith, Ian E D; Ko, Eunhwa; Campos, Sebastien; Miah, Afjal H; Mulholland, Katie E; Routly, Natasha; Buckley, Dennis L; Gustafson, Jeffrey L; Zinn, Nico; Grandi, Paola; Shimamura, Satoko; Bergamini, Giovanna; Faelth-Savitski, Maria; Bantscheff, Marcus; Cox, Carly; Gordon, Deborah A; Willard, Ryan R; Flanagan, John J; Casillas, Linda N; Votta, Bartholomew J; den Besten, Willem; Famm, Kristoffer; Kruidenier, Laurens; Carter, Paul S; Harling, John D; Churcher, Ian; Crews, Craig M


    The current predominant therapeutic paradigm is based on maximizing drug-receptor occupancy to achieve clinical benefit. This strategy, however, generally requires excessive drug concentrations to ensure sufficient occupancy, often leading to adverse side effects. Here, we describe major improvements to the proteolysis targeting chimeras (PROTACs) method, a chemical knockdown strategy in which a heterobifunctional molecule recruits a specific protein target to an E3 ubiquitin ligase, resulting in the target's ubiquitination and degradation. These compounds behave catalytically in their ability to induce the ubiquitination of super-stoichiometric quantities of proteins, providing efficacy that is not limited by equilibrium occupancy. We present two PROTACs that are capable of specifically reducing protein levels by >90% at nanomolar concentrations. In addition, mouse studies indicate that they provide broad tissue distribution and knockdown of the targeted protein in tumor xenografts. Together, these data demonstrate a protein knockdown system combining many of the favorable properties of small-molecule agents with the potent protein knockdown of RNAi and CRISPR.

  12. Development of a unique small molecule modulator of CXCR4.

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    Zhongxing Liang

    Full Text Available BACKGROUND: Metastasis, the spread and growth of tumor cells to distant organ sites, represents the most devastating attribute and plays a major role in the morbidity and mortality of cancer. Inflammation is crucial for malignant tumor transformation and survival. Thus, blocking inflammation is expected to serve as an effective cancer treatment. Among anti-inflammation therapies, chemokine modulation is now beginning to emerge from the pipeline. CXC chemokine receptor-4 (CXCR4 and its ligand stromal cell-derived factor-1 (CXCL12 interaction and the resulting cell signaling cascade have emerged as highly relevant targets since they play pleiotropic roles in metastatic progression. The unique function of CXCR4 is to promote the homing of tumor cells to their microenvironment at the distant organ sites. METHODOLOGY/PRINCIPAL FINDINGS: We describe the actions of N,N'-(1,4-phenylenebis(methylenedipyrimidin-2-amine (designated MSX-122, a novel small molecule and partial CXCR4 antagonist with properties quite unlike that of any other reported CXCR4 antagonists, which was prepared in a single chemical step using a reductive amination reaction. Its specificity toward CXCR4 was tested in a binding affinity assay and a ligand competition assay using (18F-labeled MSX-122. The potency of the compound was determined in two functional assays, Matrigel invasion assay and cAMP modulation. The therapeutic potential of MSX-122 was evaluated in three different murine models for inflammation including an experimental colitis, carrageenan induced paw edema, and bleomycin induced lung fibrosis and three different animal models for metastasis including breast cancer micrometastasis in lung, head and neck cancer metastasis in lung, and uveal melanoma micrometastasis in liver in which CXCR4 was reported to play crucial roles. CONCLUSIONS/SIGNIFICANCE: We developed a novel small molecule, MSX-122, that is a partial CXCR4 antagonist without mobilizing stem cells, which can

  13. Elucidating the germination transcriptional program using small molecules. (United States)

    Bassel, George W; Fung, Pauline; Chow, Tsz-fung Freeman; Foong, Justin A; Provart, Nicholas J; Cutler, Sean R


    The transition from seed to seedling is mediated by germination, a complex process that starts with imbibition and completes with radicle emergence. To gain insight into the transcriptional program mediating germination, previous studies have compared the transcript profiles of dry, dormant, and germinating after-ripened Arabidopsis (Arabidopsis thaliana) seeds. While informative, these approaches did not distinguish the transcriptional responses due to imbibition, shifts in metabolism, or breaking of dormancy from those triggered by the initiation of germination. In this study, three mechanistically distinct small molecules that inhibit Arabidopsis seed germination (methotrexate, 2, 4-dinitrophenol, and cycloheximide) were identified using a small-molecule screen and used to probe the germination transcriptome. Germination-responsive transcripts were defined as those with significantly altered transcript abundance across all inhibitory treatments with respect to control germinating seeds, using data from ATH1 microarrays. This analysis identified numerous germination regulators as germination responsive, including the DELLA proteins GAI, RGA, and RGL3, the abscisic acid-insensitive proteins ABI4, ABI5, ABI8, and FRY1, and the gibberellin receptor GID1A. To help visualize these and other publicly available seed microarray data, we designed a seed mRNA expression browser using the electronic Fluorescent Pictograph platform. An overall decrease in gene expression and a 5-fold greater number of transcripts identified as statistically down-regulated in drug-inhibited seeds point to a role for mRNA degradation or turnover during seed germination. The genes identified in our study as responsive to germination define potential uncharacterized regulators of this process and provide a refined transcriptional signature for germinating Arabidopsis seeds.

  14. Decoupling Activation of Heme Biosynthesis from Anaerobic Toxicity in a Molecule Active in Staphylococcus aureus. (United States)

    Dutter, Brendan F; Mike, Laura A; Reid, Paul R; Chong, Katherine M; Ramos-Hunter, Susan J; Skaar, Eric P; Sulikowski, Gary A


    Small molecules active in the pathogenic bacterium Staphylococcus aureus are valuable tools for the study of its basic biology and pathogenesis, and many molecules may provide leads for novel therapeutics. We have previously reported a small molecule, 1, which activates endogenous heme biosynthesis in S. aureus, leading to an accumulation of intracellular heme. In addition to this novel activity, 1 also exhibits toxicity towards S. aureus growing under fermentative conditions. To determine if these activities are linked and establish what features of the molecule are required for activity, we synthesized a library of analogs around the structure of 1 and screened them for activation of heme biosynthesis and anaerobic toxicity to investigate structure-activity relationships. The results of this analysis suggest that these activities are not linked. Furthermore, we have identified the structural features that promote each activity and have established two classes of molecules: activators of heme biosynthesis and inhibitors of anaerobic growth. These molecules will serve as useful probes for their respective activities without concern for the off target effects of the parent compound.

  15. A high throughput screening assay system for the identification of small molecule inhibitors of gsp.

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    Nisan Bhattacharyya

    Full Text Available Mis-sense mutations in the α-subunit of the G-protein, Gsα, cause fibrous dysplasia of bone/McCune-Albright syndrome. The biochemical outcome of these mutations is constitutively active Gsα and increased levels of cAMP. The aim of this study was to develop an assay system that would allow the identification of small molecule inhibitors specific for the mutant Gsα protein, the so-called gsp oncogene. Commercially available Chinese hamster ovary cells were stably transfected with either wild-type (WT or mutant Gsα proteins (R201C and R201H. Stable cell lines with equivalent transfected Gsα protein expression that had relatively lower (WT or higher (R201C and R201H cAMP levels were generated. These cell lines were used to develop a fluorescence resonance energy transfer (FRET-based cAMP assay in 1536-well microplate format for high throughput screening of small molecule libraries. A small molecule library of 343,768 compounds was screened to identify modulators of gsp activity. A total of 1,356 compounds with inhibitory activity were initially identified and reconfirmed when tested in concentration dose responses. Six hundred eighty-six molecules were selected for further analysis after removing cytotoxic compounds and those that were active in forskolin-induced WT cells. These molecules were grouped by potency, efficacy, and structural similarities to yield 22 clusters with more than 5 of structurally similar members and 144 singleton molecules. Seven chemotypes of the major clusters were identified for further testing and analyses.

  16. Targeting Th17 Cells with Small Molecules and Small Interference RNA. (United States)

    Lin, Hui; Song, Pingfang; Zhao, Yi; Xue, Li-Jia; Liu, Yi; Chu, Cong-Qiu


    T helper 17 (Th17) cells play a central role in inflammatory and autoimmune diseases via the production of proinflammatory cytokines interleukin- (IL-) 17, IL-17F, and IL-22. Anti-IL-17 monoclonal antibodies show potent efficacy in psoriasis but poor effect in rheumatoid arthritis (RA) and Crohn's disease. Alternative agents targeting Th17 cells may be a better way to inhibit the development and function of Th17 cells than antibodies of blocking a single effector cytokine. Retinoic acid-related orphan receptor gamma t (RORγt) which acts as the master transcription factor of Th17 differentiation has been an attractive pharmacologic target for the treatment of Th17-mediated autoimmune disease. Recent progress in technology of chemical screen and engineering nucleic acid enable two new classes of therapeutics targeting RORγt. Chemical screen technology identified several small molecule specific inhibitors of RORγt from a small molecule library. Systematic evolution of ligands by exponential enrichment (SELEX) technology enabled target specific aptamers to be isolated from a random sequence oligonucleotide library. In this review, we highlight the development and therapeutic potential of small molecules inhibiting Th17 cells by targeting RORγt and aptamer mediated CD4(+) T cell specific delivery of small interference RNA against RORγt gene expression to inhibit pathogenic effector functions of Th17 lineage.

  17. A novel caspase 8 selective small molecule potentiates TRAIL-induced cell death. (United States)

    Bucur, Octavian; Gaidos, Gabriel; Yatawara, Achani; Pennarun, Bodvael; Rupasinghe, Chamila; Roux, Jérémie; Andrei, Stefan; Guo, Bingqian; Panaitiu, Alexandra; Pellegrini, Maria; Mierke, Dale F; Khosravi-Far, Roya


    Recombinant soluble TRAIL and agonistic antibodies against TRAIL receptors (DR4 and DR5) are currently being created for clinical cancer therapy, due to their selective killing of cancer cells and high safety characteristics. However, resistance to TRAIL and other targeted therapies is an important issue facing current cancer research field. An attractive strategy to sensitize resistant malignancies to TRAIL-induced cell death is the design of small molecules that target and promote caspase 8 activation. For the first time, we describe the discovery and characterization of a small molecule that directly binds caspase 8 and enhances its activation when combined with TRAIL, but not alone. The molecule was identified through an in silico chemical screen for compounds with affinity for the caspase 8 homodimer's interface. The compound was experimentally validated to directly bind caspase 8, and to promote caspase 8 activation and cell death in single living cells or population of cells, upon TRAIL stimulation. Our approach is a proof-of-concept strategy leading to the discovery of a novel small molecule that not only stimulates TRAIL-induced apoptosis in cancer cells, but may also provide insights into the structure-function relationship of caspase 8 homodimers as putative targets in cancer.

  18. Bifunctional Pt-Si Alloys for Small Organic Molecule Electro-oxidation

    DEFF Research Database (Denmark)

    Permyakova, Anastasia Aleksandrovna; Suntivich, Jin; Han, Binghong

    Designing highly active catalysts for electro-oxidation of small organic molecules can help to reduce the anodic overpotential for more efficient utilization of hydrocarbon fuels. The challenge in developing more active electrocatalysts for electro-oxidation reactions is to satisfy the stringent...... bifunctional requirement, which demands both adsorption and water oxidation sites. In this contribution, we explore the possibility of using Pt-Si alloys to fulfill this bifunctional requirement. Silicon, a highly oxophillic element, is alloyed into Pt as a site for water oxidation, while Pt serves as a CO...... adsorption site. We will discuss the enhanced activity of Pt-Si alloys for small organic molecule oxidation, which can be attributed to the improved CO electro-oxidation kinetics on Pt-Si....

  19. Novel Small Molecule Inhibitors of Cancer Stem Cell Signaling Pathways. (United States)

    Abetov, Danysh; Mustapova, Zhanar; Saliev, Timur; Bulanin, Denis; Batyrbekov, Kanat; Gilman, Charles P


    The main aim of oncologists worldwide is to understand and then intervene in the primary tumor initiation and propagation mechanisms. This is essential to allow targeted elimination of cancer cells without altering normal mitotic cells. Currently, there are two main rival theories describing the process of tumorigenesis. According to the Stochastic Model, potentially any cell, once defunct, is capable of initiating carcinogenesis. Alternatively the Cancer Stem Cell (CSC) Model posits that only a small fraction of undifferentiated tumor cells are capable of triggering carcinogenesis. Like healthy stem cells, CSCs are also characterized by a capacity for self-renewal and the ability to generate differentiated progeny, possibly mediating treatment resistance, thus leading to tumor recurrence and metastasis. Moreover, molecular signaling profiles are similar between CSCs and normal stem cells, including Wnt, Notch and Hedgehog pathways. Therefore, development of novel chemotherapeutic agents and proteins (e.g., enzymes and antibodies) specifically targeting CSCs are attractive pharmaceutical candidates. This article describes small molecule inhibitors of stem cell pathways Wnt, Notch and Hedgehog, and their recent chemotherapy clinical trials.

  20. Small molecule mimetics of an HIV-1 gp41 fusion intermediate as vaccine leads. (United States)

    Caulfield, Michael J; Dudkin, Vadim Y; Ottinger, Elizabeth A; Getty, Krista L; Zuck, Paul D; Kaufhold, Robin M; Hepler, Robert W; McGaughey, Georgia B; Citron, Michael; Hrin, Renee C; Wang, Ying-Jie; Miller, Michael D; Joyce, Joseph G


    We describe here a novel platform technology for the discovery of small molecule mimetics of conformational epitopes on protein antigens. As a model system, we selected mimetics of a conserved hydrophobic pocket within the N-heptad repeat region of the HIV-1 envelope protein, gp41. The human monoclonal antibody, D5, binds to this target and exhibits broadly neutralizing activity against HIV-1. We exploited the antigen-binding property of D5 to select complementary small molecules using a high throughput screen of a diverse chemical collection. The resulting small molecule leads were rendered immunogenic by linking them to a carrier protein and were shown to elicit N-heptad repeat-binding antibodies in a fraction of immunized mice. Plasma from HIV-1-infected subjects shown previously to contain broadly neutralizing antibodies was found to contain antibodies capable of binding to haptens represented in the benzylpiperidine leads identified as a result of the high throughput screen, further validating these molecules as vaccine leads. Our results suggest a new paradigm for vaccine discovery using a medicinal chemistry approach to identify lead molecules that, when optimized, could become vaccine candidates for infectious diseases that have been refractory to conventional vaccine development.

  1. Multi-small molecule conjugations as new targeted delivery carriers for tumor therapy

    Directory of Open Access Journals (Sweden)

    Shan L


    Full Text Available Lingling Shan,1 Ming Liu,2 Chao Wu,1 Liang Zhao,1 Siwen Li,3 Lisheng Xu,1 Wengen Cao,1 Guizhen Gao,1 Yueqing Gu3 1Institute of Pharmaceutical Biotechnology, School of Biology and Food Engineering, Suzhou University, Suzhou, People’s Republic of China; 2Department of Biology, University of South Dakota, Vermillion, SD, USA; 3Department of Biomedical Engineering, School of Life Science and Technology, China Pharmaceutical University, Nanjing, People’s Republic of China Abstract: In response to the challenges of cancer chemotherapeutics, including poor physicochemical properties, low tumor targeting ability, and harmful side effects, we developed a new tumor-targeted multi-small molecule drug delivery platform. Using paclitaxel (PTX as a model therapeutic, we prepared two prodrugs, ie, folic acid-fluorescein-5(6-isothiocyanate-arginine-paclitaxel (FA-FITC-Arg-PTX and folic acid-5-aminofluorescein-glutamic-paclitaxel (FA-5AF-Glu-PTX, composed of folic acid (FA, target, amino acids (Arg or Glu, linker, and fluorescent dye (fluorescein in vitro or near-infrared fluorescent dye in vivo in order to better understand the mechanism of PTX prodrug targeting. In vitro and acute toxicity studies demonstrated the low toxicity of the prodrug formulations compared with the free drug. In vitro and in vivo studies indicated that folate receptor-mediated uptake of PTX-conjugated multi-small molecule carriers induced high antitumor activity. Notably, compared with free PTX and with PTX-loaded macromolecular carriers from our previous study, this multi-small molecule-conjugated strategy improved the water solubility, loading rate, targeting ability, antitumor activity, and toxicity profile of PTX. These results support the use of multi-small molecules as tumor-targeting drug delivery systems. Keywords: multi-small molecules, paclitaxel, prodrugs, targeting, tumor therapy

  2. Small molecule modulators of histone acetyltransferase p300. (United States)

    Balasubramanyam, Karanam; Swaminathan, V; Ranganathan, Anupama; Kundu, Tapas K


    Histone acetyltransferases (HATs) are a group of enzymes that play a significant role in the regulation of gene expression. These enzymes covalently modify the N-terminal lysine residues of histones by the addition of acetyl groups from acetyl-CoA. Dysfunction of these enzymes is often associated with the manifestation of several diseases, predominantly cancer. Here we report that anacardic acid from cashew nut shell liquid is a potent inhibitor of p300 and p300/CBP-associated factor histone acetyltranferase activities. Although it does not affect DNA transcription, HAT-dependent transcription from a chromatin template was strongly inhibited by anacardic acid. Furthermore, we describe the design and synthesis of an amide derivative N-(4-chloro-3-trifluoromethyl-phenyl)-2-ethoxy-6-pentadecyl-benzamide (CTPB) using anacardic acid as a synthon, which remarkably activates p300 HAT activity but not that of p300/CBP-associated factor. Although CTPB does not affect DNA transcription, it enhances the p300 HAT-dependent transcriptional activation from in vitro assembled chromatin template. However, it has no effect on histone deacetylase activity. These compounds would be useful as biological switching molecules for probing into the role of p300 in transcriptional studies and may also be useful as new chemical entities for the development of anticancer drugs.

  3. Design of a bioactive small molecule that targets r(AUUCU) repeats in spinocerebellar ataxia 10. (United States)

    Yang, Wang-Yong; Gao, Rui; Southern, Mark; Sarkar, Partha S; Disney, Matthew D


    RNA is an important target for chemical probes of function and lead therapeutics; however, it is difficult to target with small molecules. One approach to tackle this problem is to identify compounds that target RNA structures and utilize them to multivalently target RNA. Here we show that small molecules can be identified to selectively bind RNA base pairs by probing a library of RNA-focused small molecules. A small molecule that selectively binds AU base pairs informed design of a dimeric compound (2AU-2) that targets the pathogenic RNA, expanded r(AUUCU) repeats, that causes spinocerebellar ataxia type 10 (SCA10) in patient-derived cells. Indeed, 2AU-2 (50 nM) ameliorates various aspects of SCA10 pathology including improvement of mitochondrial dysfunction, reduced activation of caspase 3, and reduction of nuclear foci. These studies provide a first-in-class chemical probe to study SCA10 RNA toxicity and potentially define broadly applicable compounds targeting RNA AU base pairs in cells.

  4. Small Molecule Modulator of p53 Signaling Pathway: Application for Radiosensitizing or Radioprotection Agents

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Sang Taek; Cho, Mun Ju; Gwak, Jung Sug; Ryu, Min Jung [PharmacoGenomics Research Center, Inje University, Busan (Korea, Republic of); Song, Jie Young; Yun, Yeon Sook [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)


    The tumor suppressor p53 is key molecule to protect the cell against genotoxic stress and..the most frequently cancer cells. Lack of functional accompanied by high rate of genomic instability, rapid tumor progression, resistance to anticancer therapy, and increased angiogenesis. In response to DNA damage, p53 protein rapidly accumulated through attenuated proteolysis and is also activated as transcription factor. Activated p53 up-regulates target genes involved in cell cycle arrest and/or apoptosis and then lead to suppression of malignant transformation and the maintenance of genomic integrity. Chemical genetics is a new technology to uncover the signaling networks that regulated biological phenotype using exogenous reagents such as small molecules. Analogous to classical forward genetic screens in model organism, this approach makes use of high throughput, phenotypic assay to identify small molecules that disrupt gene product function in a way that alters a phenotype of interest. Recently, interesting small molecules were identified from cell based high throughput screening and its target protein or mechanism of action were identified by various methods including affinity chromatography, protein array profiling, mRNA or phage display, transcription profiling, and RNA interference.

  5. High performance photovoltaic applications using solution-processed small molecules. (United States)

    Chen, Yongsheng; Wan, Xiangjian; Long, Guankui


    Energy remains a critical issue for the survival and prosperity of humancivilization. Many experts believe that the eventual solution for sustainable energy is the use of direct solar energy as the main energy source. Among the options for renewable energy, photovoltaic technologies that harness solar energy offer a way to harness an unlimited resource and minimum environment impact in contrast with other alternatives such as water, nuclear, and wind energy. Currently, almost all commercial photovoltaic technologies use Si-based technology, which has a number of disadvantages including high cost, lack of flexibility, and the serious environmental impact of the Si industry. Other technologies, such as organic photovoltaic (OPV) cells, can overcome some of these issues. Today, polymer-based OPV (P-OPV) devices have achieved power conversion efficiencies (PCEs) that exceed 9%. Compared with P-OPV, small molecules based OPV (SM-OPV) offers further advantages, including a defined structure for more reproducible performance, higher mobility and open circuit voltage, and easier synthetic control that leads to more diversified structures. Therefore, while largely undeveloped, SM-OPV is an important emerging technology with performance comparable to P-OPV. In this Account, we summarize our recent results on solution-processed SM-OPV. We believe that solution processing is essential for taking full advantage of OPV technologies. Our work started with the synthesis of oligothiophene derivatives with an acceptor-donor-acceptor (A-D-A) structure. Both the backbone conjugation length and electron withdrawing terminal groups play an important role in the light absorption, energy levels and performance of the devices. Among those molecules, devices using a 7-thiophene-unit backbone and a 3-ethylrhodanine (RD) terminal unit produced a 6.1% PCE. With the optimized conjugation length and terminal unit, we borrowed from the results with P-OPV devices to optimize the backbone. Thus we

  6. Stereoselective Modulation of P-Glycoprotein by Chiral Small Molecules. (United States)

    Carocci, Alessia; Catalano, Alessia; Turi, Francesco; Lovece, Angelo; Cavalluzzi, Maria M; Bruno, Claudio; Colabufo, Nicola A; Contino, Marialessandra; Perrone, Maria G; Franchini, Carlo; Lentini, Giovanni


    Inhibition of drug efflux pumps such as P-glycoprotein (P-gp) is an approach toward combating multidrug resistance, which is a significant hurdle in current cancer treatments. To address this, N-substituted aryloxymethyl pyrrolidines were designed and synthesized in their homochiral forms in order to investigate the stereochemical requirements for the binding site of P-gp. Our study provides evidence that the chiral property of molecules could be a strategy for improving the capacity for interacting with P-gp, as the most active compounds of the series stereoselectively modulated this efflux pump. The naphthalene-1-yl analogue (R)-2-[(2,3-dichlorophenoxy)methyl]-1-(naphthalen-1-ylmethyl)pyrrolidine) [(R)-7 a] emerged foremost for its potency and stereoselectivity toward P-gp, with the S enantiomer being nearly inactive. The modulation of P-gp by (R)-7 a involved consumption of ATP, thus demonstrating that the compound behaves as a P-gp substrate.

  7. Remote control of therapeutic T cells through a small molecule-gated chimeric receptor. (United States)

    Wu, Chia-Yung; Roybal, Kole T; Puchner, Elias M; Onuffer, James; Lim, Wendell A


    There is growing interest in using engineered cells as therapeutic agents. For example, synthetic chimeric antigen receptors (CARs) can redirect T cells to recognize and eliminate tumor cells expressing specific antigens. Despite promising clinical results, these engineered T cells can exhibit excessive activity that is difficult to control and can cause severe toxicity. We designed "ON-switch" CARs that enable small-molecule control over T cell therapeutic functions while still retaining antigen specificity. In these split receptors, antigen-binding and intracellular signaling components assemble only in the presence of a heterodimerizing small molecule. This titratable pharmacologic regulation could allow physicians to precisely control the timing, location, and dosage of T cell activity, thereby mitigating toxicity. This work illustrates the potential of combining cellular engineering with orthogonal chemical tools to yield safer therapeutic cells that tightly integrate cell-autonomous recognition and user control.

  8. Modulated iontophoretic delivery of small and large molecules through microchannels. (United States)

    Kumar, Vijay; Banga, Ajay K


    The objective of this work was to modulate transdermal drug delivery by iontophoresis though skin microchannels created by microneedles. Calcein and human growth hormone were used as a model small and large molecule, respectively. In vitro permeation studies were performed on porcine ear skin under three different settings: (a) modulated iontophoresis alone, (b) pretreatment with microneedles and (c) combination of microneedles pretreatment and modulated iontophoresis. For modulated iontophoresis, 0.5 mA/cm(2) current was applied for 1h each at 2nd and 6th hour of the study. Methylene blue staining, calcein imaging and pore permeability index suggested maltose microneedles created uniform microchannels in skin. Application of iontophoresis provided two peaks in flux of 1.04 μg/(cm(2)h) at 4th hour and 2.09 μg/(cm(2)h) at 8th hour of study for calcein. These peaks in flux were significant higher when skin was pretreated with microneedles (piontophoresis. This combination also provided significant increase in cumulative amount of calcein and human growth hormone delivered as compared to microneedles or iontophoresis alone (piontophoresis can be used to modulate drug delivery across skin microchannels created by microneedles.

  9. Small Molecule Identification with MOLGEN and Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Markus Meringer


    Full Text Available This paper details the MOLGEN entries for the 2012 CASMI contest for small molecule identification to demonstrate structure elucidation using structure generation approaches. Different MOLGEN programs were used for different categories, including MOLGEN–MS/MS for Category 1, MOLGEN 3.5 and 5.0 for Category 2 and MOLGEN–MS for Categories 3 and 4. A greater focus is given to Categories 1 and 2, as most CASMI participants entered these categories. The settings used and the reasons behind them are described in detail, while various evaluations are used to put these results into perspective. As one author was also an organiser of CASMI, these submissions were not part of the official CASMI competition, but this paper provides an insight into how unknown identification could be performed using structure generation approaches. The approaches are semi-automated (category dependent and benefit greatly from user experience. Thus, the results presented and discussed here may be better than those an inexperienced user could obtain with MOLGEN programs.

  10. Small-molecule kinase inhibitors: an analysis of FDA-approved drugs

    DEFF Research Database (Denmark)

    Wu, Peng; Nielsen, Thomas Eiland; Clausen, Mads Hartvig


    Small-molecule kinase inhibitors (SMKIs), 28 of which are approved by the US Food and Drug Administration (FDA), have been actively pursued as promising targeted therapeutics. Here, we assess the key structural and physicochemical properties, target selectivity and mechanism of function, and ther...... to be unreliable. Although previous SMKI research was concentrated on tyrosine kinase inhibitors for cancer treatment, recent progress indicates diversification of SMKI research in terms of new targets, mechanistic types, and therapeutic indications....

  11. Saururus cernuus Lignans - Potent Small Molecule Inhibitors of Hypoxia-Inducible Factor-1


    Hossain, Chowdhury Faiz; Kim, Yong-Pil; Baerson, Scott R; Zhang, Lei; Bruick, Richard K.; Mohammed, Kaleem A.; Agarwal, Ameeta K.; Nagle, Dale G.; Zhou, Yu-Dong


    Hypoxia-inducible factor-1 (HIF-1) represents an important tumor-selective therapeutic target for solid tumors. In search of novel small molecule HIF-1 inhibitors, 5400 natural product-rich extracts from plants, marine organisms, and microbes were examined for HIF-1 inhibitory activities using a cell-based reporter assay. Bioassay-guided fractionation and isolation, followed by structure elucidation, yielded three potent natural product-derived HIF-1 inhibitors and two structurally related in...

  12. Nonlinear Transport in Organic Thin Film Transistors with Soluble Small Molecule Semiconductor. (United States)

    Kim, Hyeok; Song, Dong-Seok; Kwon, Jin-Hyuk; Jung, Ji-Hoon; Kim, Do-Kyung; Kim, SeonMin; Kang, In Man; Park, Jonghoo; Tae, Heung-Sik; Battaglini, Nicolas; Lang, Philippe; Horowitz, Gilles; Bae, Jin-Hyuk


    Nonlinear transport is intensively explained through Poole-Frenkel (PF) transport mechanism in organic thin film transistors with solution-processed small molecules, which is, 6,13-bis(triisopropylsilylethynyl) (TIPS) pentacene. We outline a detailed electrical study that identifies the source to drain field dependent mobility. Devices with diverse channel lengths enable the extensive exhibition of field dependent mobility due to thermal activation of carriers among traps.

  13. A small molecule restores function to TRPML1 mutant isoforms responsible for mucolipidosis type IV. (United States)

    Chen, Cheng-Chang; Keller, Marco; Hess, Martin; Schiffmann, Raphael; Urban, Nicole; Wolfgardt, Annette; Schaefer, Michael; Bracher, Franz; Biel, Martin; Wahl-Schott, Christian; Grimm, Christian


    Mucolipidosis type IV (MLIV) is an autosomal recessive lysosomal storage disorder often characterized by severe neurodevelopmental abnormalities and neuro-retinal degeneration. Mutations in the TRPML1 gene are causative for MLIV. We used lead optimization strategies to identify--and MLIV patient fibroblasts to test--small-molecule activators for their potential to restore TRPML1 mutant channel function. Using the whole-lysosome planar patch-clamp technique, we found that activation of MLIV mutant isoforms by the endogenous ligand PI(3,5)P2 is strongly reduced, while activity can be increased using synthetic ligands. We also found that the F465L mutation renders TRPML1 pH insensitive, while F408Δ impacts synthetic ligand binding. Trafficking defects and accumulation of zinc in lysosomes of MLIV mutant fibroblasts can be rescued by the small molecule treatment. Collectively, our data demonstrate that small molecules can be used to restore channel function and rescue disease associated abnormalities in patient cells expressing specific MLIV point mutations.

  14. Molecular locks and keys: the role of small molecules in phytohormone research

    Directory of Open Access Journals (Sweden)

    Sandra eFonseca


    Full Text Available Plant adaptation, growth and development rely on the integration of many environmental and endogenous signals that collectively determine the overall plant phenotypic plasticity. Plant signalling molecules, also known as phytohormones, are fundamental to this process. These molecules act at low concentrations and regulate multiple aspects of plant fitness and development via complex signalling networks. By its nature, phytohormone research lies at the interface between chemistry and biology. Classically, the scientific community has always used synthetic phytohormones and analogs to study hormone functions and responses. However, recent advances in synthetic and combinational chemistry, have allowed a new field, plant chemical biology, to emerge and this has provided a powerful tool with which to study phytohormone function.Plant chemical biology is helping to address some of the most enduring questions in phytohormone research such as: Are there still undiscovered plant hormones? How can we identify novel signalling molecules? How can plants activate specific hormone responses in a tissue-specific manner? How can we modulate hormone responses in one developmental context without inducing detrimental effects on other processes? The chemical genomics approaches rely on the identification of small molecules modulating different biological processes and have recently identified active forms of plant hormones and molecules regulating many aspects of hormone synthesis, transport and response. We envision that the field of chemical genomics will continue to provide novel molecules able to elucidate specific aspects of hormone-mediated responses. In addition, compounds blocking specific responses could uncover how complex biological responses are regulated. As we gain information about such compounds we can design small alterations to the chemical structure to further alter specificity, enhance affinity or modulate the activity of these compounds.

  15. Molecular locks and keys: the role of small molecules in phytohormone research. (United States)

    Fonseca, Sandra; Rosado, Abel; Vaughan-Hirsch, John; Bishopp, Anthony; Chini, Andrea


    Plant adaptation, growth and development rely on the integration of many environmental and endogenous signals that collectively determine the overall plant phenotypic plasticity. Plant signaling molecules, also known as phytohormones, are fundamental to this process. These molecules act at low concentrations and regulate multiple aspects of plant fitness and development via complex signaling networks. By its nature, phytohormone research lies at the interface between chemistry and biology. Classically, the scientific community has always used synthetic phytohormones and analogs to study hormone functions and responses. However, recent advances in synthetic and combinational chemistry, have allowed a new field, plant chemical biology, to emerge and this has provided a powerful tool with which to study phytohormone function. Plant chemical biology is helping to address some of the most enduring questions in phytohormone research such as: Are there still undiscovered plant hormones? How can we identify novel signaling molecules? How can plants activate specific hormone responses in a tissue-specific manner? How can we modulate hormone responses in one developmental context without inducing detrimental effects on other processes? The chemical genomics approaches rely on the identification of small molecules modulating different biological processes and have recently identified active forms of plant hormones and molecules regulating many aspects of hormone synthesis, transport and response. We envision that the field of chemical genomics will continue to provide novel molecules able to elucidate specific aspects of hormone-mediated mechanisms. In addition, compounds blocking specific responses could uncover how complex biological responses are regulated. As we gain information about such compounds we can design small alterations to the chemical structure to further alter specificity, enhance affinity or modulate the activity of these compounds.

  16. A Small Molecule, Which Competes with MAdCAM-1, Activates Integrin α4β7 and Fails to Prevent Mucosal Transmission of SHIV-SF162P3.

    Directory of Open Access Journals (Sweden)

    Géraldine Arrode-Brusés


    Full Text Available Mucosal HIV-1 transmission is inefficient. However, certain viral and host characteristics may play a role in facilitating HIV acquisition and systemic expansion. Cells expressing high levels of integrin α4β7 have been implicated in favoring the transmission process and the infusion of an anti-α4β7 mAb (RM-Act-1 prior to, and during a repeated low-dose vaginal challenge (RLDC regimen with SIVmac251 reduced SIV acquisition and protected the gut-associated lymphoid tissues (GALT in the macaques that acquired SIV. α4β7 expression is required for lymphocyte trafficking to the gut lamina propria and gut inductive sites. Several therapeutic strategies that target α4β7 have been shown to be effective in treating inflammatory conditions of the intestine, such as inflammatory bowel disease (IBD. To determine if blocking α4β7 with ELN, an orally available anti-α4 small molecule, would inhibit SHIV-SF162P3 acquisition, we tested its ability to block MAdCAM-1 (α4β7 natural ligand and HIV-gp120 binding in vitro. We studied the pharmacokinetic profile of ELN after oral and vaginal delivery in macaques. Twenty-six macaques were divided into 3 groups: 9 animals were treated with ELN orally, 9 orally and vaginally and 8 were used as controls. All animals were challenged intra-vaginally with SHIV-SF162P3 using the RLDC regimen. We found that ELN did not protect macaques from SHIV acquisition although it reduced the SHIV-induced inflammatory status during the acute phase of infection. Notably, integrins can exist in different activation states and, comparing the effect of ELN and the anti-α4β7 mAb RM-Act-1 that reduced susceptibility to SIV infection, we determined that ELN induces the active conformation of α4β7, while RM-Act-1 inhibits its activation through an allosteric mechanism. These results suggest that inhibition of α4β7 activation may be necessary to reduce susceptibility to SIV/SHIV infection and highlight the complexity of anti

  17. Fluorination-enabled optimal morphology leads to over 11% efficiency for inverted small-molecule organic solar cells (United States)

    Deng, Dan; Zhang, Yajie; Zhang, Jianqi; Wang, Zaiyu; Zhu, Lingyun; Fang, Jin; Xia, Benzheng; Wang, Zhen; Lu, Kun; Ma, Wei; Wei, Zhixiang


    Solution-processable small molecules for organic solar cells have attracted intense attention for their advantages of definite molecular structures compared with their polymer counterparts. However, the device efficiencies based on small molecules are still lower than those of polymers, especially for inverted devices, the highest efficiency of which is <9%. Here we report three novel solution-processable small molecules, which contain π-bridges with gradient-decreased electron density and end acceptors substituted with various fluorine atoms (0F, 1F and 2F, respectively). Fluorination leads to an optimal active layer morphology, including an enhanced domain purity, the formation of hierarchical domain size and a directional vertical phase gradation. The optimal morphology balances charge separation and transfer, and facilitates charge collection. As a consequence, fluorinated molecules exhibit excellent inverted device performance, and an average power conversion efficiency of 11.08% is achieved for a two-fluorine atom substituted molecule.

  18. Rational design of small molecule inhibitors targeting the Ras GEF, SOS1 (United States)

    Evelyn, Chris R.; Duan, Xin; Biesiada, Jacek; Seibel, William L.; Meller, Jaroslaw; Zheng, Yi


    Summary Ras GTPases regulate intracellular signaling involved in cell proliferation. Elevated Ras signaling activity has been associated with human cancers. Ras activation is catalyzed by guanine-nucleotide exchange factors (GEFs), of which SOS1 is a major member that transduces receptor tyrosine kinase signaling to Ras. We have developed a rational approach coupling virtual screening with experimental screening in identifying small-molecule inhibitors targeting the catalytic site of SOS1 and SOS1-regulated Ras activity. A lead inhibitor, NSC-658497, is found to bind to SOS1, competitively suppresses SOS1-Ras interaction, and dose-dependently inhibits SOS1 GEF activity. Mutagenesis and structure-activity relationship studies map the NSC-658497 site of action to the SOS1 catalytic site, and define the chemical moieties in the inhibitor essential for the activity. NSC-658497 showed dose-dependent efficacy in inhibiting Ras, downstream signaling activities, and associated cell proliferation. These studies establish a proof of principle for rational design of small-molecule inhibitors targeting Ras GEF enzymatic activity. PMID:25455859

  19. Rational design of small molecule inhibitors targeting the Ras GEF, SOS1. (United States)

    Evelyn, Chris R; Duan, Xin; Biesiada, Jacek; Seibel, William L; Meller, Jaroslaw; Zheng, Yi


    Ras GTPases regulate intracellular signaling involved in cell proliferation. Elevated Ras signaling activity has been associated with human cancers. Ras activation is catalyzed by guanine nucleotide exchange factors (GEFs), of which SOS1 is a major member that transduces receptor tyrosine kinase signaling to Ras. We have developed a rational approach coupling virtual screening with experimental screening in identifying small-molecule inhibitors targeting the catalytic site of SOS1 and SOS1-regulated Ras activity. A lead inhibitor, NSC-658497, was found to bind to SOS1, competitively suppress SOS1-Ras interaction, and dose-dependently inhibit SOS1 GEF activity. Mutagenesis and structure-activity relationship studies map the NSC-658497 site of action to the SOS1 catalytic site, and define the chemical moieties in the inhibitor essential for the activity. NSC-658497 showed dose-dependent efficacy in inhibiting Ras, downstream signaling activities, and associated cell proliferation. These studies establish a proof of principle for rational design of small-molecule inhibitors targeting Ras GEF enzymatic activity.

  20. A shortcut to identifying small molecule signals that regulate behavior and development in Caenorhabditis elegans. (United States)

    Pungaliya, Chirag; Srinivasan, Jagan; Fox, Bennett W; Malik, Rabia U; Ludewig, Andreas H; Sternberg, Paul W; Schroeder, Frank C


    Small molecule metabolites play important roles in Caenorhabditis elegans biology, but effective approaches for identifying their chemical structures are lacking. Recent studies revealed that a family of glycosides, the ascarosides, differentially regulate C. elegans development and behavior. Low concentrations of ascarosides attract males and thus appear to be part of the C. elegans sex pheromone, whereas higher concentrations induce developmental arrest at the dauer stage, an alternative, nonaging larval stage. The ascarosides act synergistically, which presented challenges for their identification via traditional activity-guided fractionation. As a result the chemical characterization of the dauer and male attracting pheromones remained incomplete. Here, we describe the identification of several additional pheromone components by using a recently developed NMR-spectroscopic approach, differential analysis by 2D NMR spectroscopy (DANS), which simplifies linking small molecule metabolites with their biological function. DANS-based comparison of wild-type C. elegans and a signaling-deficient mutant, daf-22, enabled identification of 3 known and 4 previously undescribed ascarosides, including a compound that features a p-aminobenzoic acid subunit. Biological testing of synthetic samples of these compounds revealed additional evidence for synergy and provided insights into structure-activity relationships. Using a combination of the three most active ascarosides allowed full reconstitution of the male-attracting activity of wild-type pheromone extract. Our results highlight the efficacy of DANS as a method for identifying small-molecule metabolites and placing them within a specific genetic context. This study further supports the hypothesis that ascarosides represent a structurally diverse set of nematode signaling molecules regulating major life history traits.

  1. Suppression of the FOXM1 transcriptional programme via novel small molecule inhibition. (United States)

    Gormally, Michael V; Dexheimer, Thomas S; Marsico, Giovanni; Sanders, Deborah A; Lowe, Christopher; Matak-Vinković, Dijana; Michael, Sam; Jadhav, Ajit; Rai, Ganesha; Maloney, David J; Simeonov, Anton; Balasubramanian, Shankar


    The transcription factor FOXM1 binds to sequence-specific motifs on DNA (C/TAAACA) through its DNA-binding domain (DBD) and activates proliferation- and differentiation-associated genes. Aberrant overexpression of FOXM1 is a key feature in oncogenesis and progression of many human cancers. Here--from a high-throughput screen applied to a library of 54,211 small molecules--we identify novel small molecule inhibitors of FOXM1 that block DNA binding. One of the identified compounds, FDI-6 (NCGC00099374), is characterized in depth and is shown to bind directly to FOXM1 protein, to displace FOXM1 from genomic targets in MCF-7 breast cancer cells, and induce concomitant transcriptional downregulation. Global transcript profiling of MCF-7 cells by RNA-seq shows that FDI-6 specifically downregulates FOXM1-activated genes with FOXM1 occupancy confirmed by ChIP-PCR. This small molecule-mediated effect is selective for FOXM1-controlled genes with no effect on genes regulated by homologous forkhead family factors.

  2. Small-molecule agonists for the glucagon-like peptide 1 receptor

    DEFF Research Database (Denmark)

    Knudsen, Lotte Bjerre; Kiel, Dan; Teng, Min;


    described and none in the B family of the G protein coupled receptors to which the GLP-1 receptor belongs. We have discovered a series of small molecules known as ago-allosteric modulators selective for the human GLP-1 receptor. These compounds act as both allosteric activators of the receptor...... and independent agonists. Potency of GLP-1 was not changed by the allosteric agonists, but affinity of GLP-1 for the receptor was increased. The most potent compound identified stimulates glucose-dependent insulin release from normal mouse islets but, importantly, not from GLP-1 receptor knockout mice. Also......The peptide hormone glucagon-like peptide (GLP)-1 has important actions resulting in glucose lowering along with weight loss in patients with type 2 diabetes. As a peptide hormone, GLP-1 has to be administered by injection. Only a few small-molecule agonists to peptide hormone receptors have been...

  3. Radiolabeled Small Molecule Protein Kinase Inhibitors for Imaging with PET or SPECT

    Directory of Open Access Journals (Sweden)

    Justin W. Hicks


    Full Text Available Imaging protein kinase expression with radiolabeled small molecule inhibitors has been actively pursued to monitor the clinical potential of targeted therapeutics and treatments as well as to determine kinase receptor density changes related to disease progression. The goal of the present review is to provide an overview of the breadth of radiolabeled small molecules that have been synthesized to target intracellular protein kinases, not only for imaging in oncology, but also for other areas of interest, particularly the central nervous system.  Considerable radiotracer development has focused on imaging receptor tyrosine kinases of growth factors, protein kinases A, B and C, and glycogen synthase kinase–3β. Design considerations, structural attributes and relevant biological results are summarized.

  4. Transportable, Chemical Genetic Methodology for the Small Molecule-Mediated Inhibition of Heat Shock Factor 1. (United States)

    Moore, Christopher L; Dewal, Mahender B; Nekongo, Emmanuel E; Santiago, Sebasthian; Lu, Nancy B; Levine, Stuart S; Shoulders, Matthew D


    Proteostasis in the cytosol is governed by the heat shock response. The master regulator of the heat shock response, heat shock factor 1 (HSF1), and key chaperones whose levels are HSF1-regulated have emerged as high-profile targets for therapeutic applications ranging from protein misfolding-related disorders to cancer. Nonetheless, a generally applicable methodology to selectively and potently inhibit endogenous HSF1 in a small molecule-dependent manner in disease model systems remains elusive. Also problematic, the administration of even highly selective chaperone inhibitors often has the side effect of activating HSF1 and thereby inducing a compensatory heat shock response. Herein, we report a ligand-regulatable, dominant negative version of HSF1 that addresses these issues. Our approach, which required engineering a new dominant negative HSF1 variant, permits dosable inhibition of endogenous HSF1 with a selective small molecule in cell-based model systems of interest. The methodology allows us to uncouple the pleiotropic effects of chaperone inhibitors and environmental toxins from the concomitantly induced compensatory heat shock response. Integration of our method with techniques to activate HSF1 enables the creation of cell lines in which the cytosolic proteostasis network can be up- or down-regulated by orthogonal small molecules. Selective, small molecule-mediated inhibition of HSF1 has distinctive implications for the proteostasis of both chaperone-dependent globular proteins and aggregation-prone intrinsically disordered proteins. Altogether, this work provides critical methods for continued exploration of the biological roles of HSF1 and the therapeutic potential of heat shock response modulation.

  5. Terminal protection of small molecule-linked ssDNA-SWNT nanoassembly for sensitive detection of small molecule and protein interaction

    Institute of Scientific and Technical Information of China (English)

    Yu Wang; Dian-Ming Zhou; Zhan Wu; Li-Juan Tang; Jian-Hui Jiang


    The interactions between small molecules and proteins constitute a critical regulatory mechanism in many fundamental biological processes.A novel biosensing strategy has been developed for sensitive and selective detection of small molecule and protein interaction on the basis of terminal protection of small molecule-linked ssDNA-SWNT nanoassembly.The developed strategy is demonstrated using folate and its binding protein folate receptor (FR) as a model case.The results reveal the developed technique displays superb resistance to non-specific binding,very low detection limit as low as subnanomolar,and a wide dynamic range from 100 pmol/L to 500 nmol/L of FR.Thus,it may offer a simple,cost-effective,highly selective and sensitive platform for homogeneous fluorescence detection of small molecule-protein interaction and related biochemical studies.

  6. Photophysics of thermally activated delayed fluorescence molecules (United States)

    Dias, Fernando B.; Penfold, Thomas J.; Monkman, Andrew P.


    Thermally activated delayed fluorescence (TADF) has recently emerged as one of the most attractive methods for harvesting triplet states in metal-free organic materials for application in organic light emitting diodes (OLEDs). A large number of TADF molecules have been reported in the literature with the purpose of enhancing the efficiency of OLEDs by converting non-emissive triplet states into emissive singlet states. TADF emitters are able to harvest both singlets and triplet states through fluorescence (prompt and delayed), the latter due to the thermally activated reverse intersystem crossing mechanism that allows up-conversion of low energy triplet states to the emissive singlet level. This allows otherwise pure fluorescent OLEDs to overcome their intrinsic limit of 25% internal quantum efficiency (IQE), which is imposed by the 1:3 singlet–triplet ratio arising from the recombination of charges (electrons and holes). TADF based OLEDS with IQEs close to 100% are now routinely fabricated in the green spectral region. There is also significant progress for blue emitters. However, red emitters still show relatively low efficiencies. Despite the significant progress that has been made in recent years, still significant challenges persist to achieve full understanding of the TADF mechanism and improve the stability of these materials. These questions need to be solved in order to fully implement TADF in OLEDs and expand their application to other areas. To date, TADF has been exploited mainly in the field of OLEDs, but applications in other areas, such as sensing and fluorescence microscopies, are envisaged. In this review, the photophysics of TADF molecules is discussed, summarising current methods to characterise these materials and the current understanding of the TADF mechanism in various molecular systems.

  7. Characteristics of product recalls of biopharmaceuticals and small-molecule drugs in the USA. (United States)

    Ebbers, Hans C; de Tienda, Nina Fuentes; Hoefnagel, Marcel C; Nibbeling, Ria; Mantel-Teeuwisse, Aukje K


    Compared with chemically synthesized small-molecule drugs, the manufacturing process of biopharmaceuticals is more complex. Unexpected changes to product characteristics following manufacturing changes have given rise to calls for robust systems to monitor the postauthorization safety of biopharmaceuticals. We compared quality-related product recalls in the USA of biopharmaceuticals and of small molecules. Although the reasons for recalls for biopharmaceuticals differed from those for small molecules, adverse events were rarely reported. The relative contribution of recalls that could cause serious adverse health consequences was not greater for biopharmaceuticals than for small molecules. Therefore, these data do not give rise to concerns that biopharmaceuticals are more frequently associated with unexpected safety concerns.

  8. Ambient roll-to-roll fabrication of flexible solar cells based on small molecules

    DEFF Research Database (Denmark)

    Lin, Yuze; Dam, Henrik Friis; Andersen, Thomas Rieks;


    All solution-processed roll-to-roll flexible solar cells based on a starshaped small molecule donor and PCBMacceptor were fabricated by slot-die coating, as the first successful example reported for small molecule roll-to-roll flexible solar cells.......All solution-processed roll-to-roll flexible solar cells based on a starshaped small molecule donor and PCBMacceptor were fabricated by slot-die coating, as the first successful example reported for small molecule roll-to-roll flexible solar cells....

  9. Small-molecule modulators of Hedgehog signaling: identification and characterization of Smoothened agonists and antagonists

    Directory of Open Access Journals (Sweden)

    Shulok Janine


    Full Text Available Abstract Background The Hedgehog (Hh signaling pathway is vital to animal development as it mediates the differentiation of multiple cell types during embryogenesis. In adults, Hh signaling can be activated to facilitate tissue maintenance and repair. Moreover, stimulation of the Hh pathway has shown therapeutic efficacy in models of neuropathy. The underlying mechanisms of Hh signal transduction remain obscure, however: little is known about the communication between the pathway suppressor Patched (Ptc, a multipass transmembrane protein that directly binds Hh, and the pathway activator Smoothened (Smo, a protein that is related to G-protein-coupled receptors and is capable of constitutive activation in the absence of Ptc. Results We have identified and characterized a synthetic non-peptidyl small molecule, Hh-Ag, that acts as an agonist of the Hh pathway. This Hh agonist promotes cell-type-specific proliferation and concentration-dependent differentiation in vitro, while in utero it rescues aspects of the Hh-signaling defect in Sonic hedgehog-null, but not Smo-null, mouse embryos. Biochemical studies with Hh-Ag, the Hh-signaling antagonist cyclopamine, and a novel Hh-signaling inhibitor Cur61414, reveal that the action of all these compounds is independent of Hh-protein ligand and of the Hh receptor Ptc, as each binds directly to Smo. Conclusions Smo can have its activity modulated directly by synthetic small molecules. These studies raise the possibility that Hh signaling may be regulated by endogenous small molecules in vivo and provide potent compounds with which to test the therapeutic value of activating the Hh-signaling pathway in the treatment of traumatic and chronic degenerative conditions.

  10. Design, synthesis and SAR analysis of novel potent and selective small molecule antagonists of NPBWR1 (GPR7). (United States)

    Urbano, Mariangela; Guerrero, Miguel; Zhao, Jian; Velaparthi, Subash; Saldanha, S Adrian; Chase, Peter; Wang, Zhiwei; Civelli, Olivier; Hodder, Peter; Schaeffer, Marie-Therese; Brown, Steven; Rosen, Hugh; Roberts, Edward


    Novel small molecule antagonists of NPBWR1 (GPR7) are herein reported. A high-throughput screening (HTS) of the Molecular Libraries-Small Molecule Repository library identified 5-chloro-4-(4-methoxyphenoxy)-2-(p-tolyl)pyridazin-3(2H)-one as a NPBWR1 hit antagonist with micromolar activity. Design, synthesis and structure-activity relationships study of the HTS-derived hit led to the identification of 5-chloro-2-(3,5-dimethylphenyl)-4-(4-methoxyphenoxy)pyridazin-3(2H)-one lead molecule with submicromolar antagonist activity at the target receptor and high selectivity against a panel of therapeutically relevant off-target proteins. This lead molecule may provide a pharmacological tool to clarify the molecular basis of the in vivo physiological function and therapeutic utility of NPBWR1 in diverse disease areas including inflammatory pain and eating disorders.

  11. Small molecule mimetics of an interferon-α receptor interacting domain. (United States)

    Bello, Angelica M; Wei, Lianhu; Majchrzak-Kita, Beata; Salum, Noruê; Purohit, Meena K; Fish, Eleanor N; Kotra, Lakshmi P


    Small molecules that mimic IFN-α epitopes that interact with the cell surface receptor, IFNAR, would be useful therapeutics. One such 8-amino acid region in IFN-α2, designated IRRP-1, was used to derive 11 chemical compounds that belong to 5 distinct chemotypes, containing the molecular features represented by the key residues Leu30, Arg33, and Asp35 in IRRP-1. Three of these compounds exhibited potential mimicry to IRRP-1 and, in cell based assays, as predicted, effectively inhibited IFNAR activation by IFN-α. Of these, compound 3 did not display cell toxicity and reduced IFN-α-inducible STAT1 phosphorylation and STAT-DNA binding. Based on physicochemical properties' analyses, our data suggest that moieties with acidic pKa on the small molecule may be a necessary element for mimicking the carboxyl group of Asp35 in IRRP-1. Our data confirm the relevance of this strategy of molecular mimicry of ligand-receptor interaction domains of protein partners for small molecule drug discovery.

  12. Identification of the first small-molecule inhibitor of the REV7 DNA repair protein interaction. (United States)

    Actis, Marcelo L; Ambaye, Nigus D; Evison, Benjamin J; Shao, Youming; Vanarotti, Murugendra; Inoue, Akira; McDonald, Ezelle T; Kikuchi, Sotaro; Heath, Richard; Hara, Kodai; Hashimoto, Hiroshi; Fujii, Naoaki


    DNA interstrand crosslink (ICL) repair (ICLR) has been implicated in the resistance of cancer cells to ICL-inducing chemotherapeutic agents. Despite the clinical significance of ICL-inducing chemotherapy, few studies have focused on developing small-molecule inhibitors for ICLR. The mammalian DNA polymerase ζ, which comprises the catalytic subunit REV3L and the non-catalytic subunit REV7, is essential for ICLR. To identify small-molecule compounds that are mechanistically capable of inhibiting ICLR by targeting REV7, high-throughput screening and structure-activity relationship (SAR) analysis were performed. Compound 1 was identified as an inhibitor of the interaction of REV7 with the REV7-binding sequence of REV3L. Compound 7 (an optimized analog of compound 1) bound directly to REV7 in nuclear magnetic resonance analyses, and inhibited the reactivation of a reporter plasmid containing an ICL in between the promoter and reporter regions. The normalized clonogenic survival of HeLa cells treated with cisplatin and compound 7 was lower than that for cells treated with cisplatin only. These findings indicate that a small-molecule inhibitor of the REV7/REV3L interaction can chemosensitize cells by inhibiting ICLR.

  13. Small Molecule Inhibition of microRNA-210 Reprograms an Oncogenic Hypoxic Circuit. (United States)

    Costales, Matthew G; Haga, Christopher L; Velagapudi, Sai Pradeep; Childs-Disney, Jessica L; Phinney, Donald G; Disney, Matthew D


    A hypoxic state is critical to the metastatic and invasive characteristics of cancer. Numerous pathways play critical roles in cancer maintenance, many of which include noncoding RNAs such as microRNA (miR)-210 that regulates hypoxia inducible factors (HIFs). Herein, we describe the identification of a small molecule named Targapremir-210 that binds to the Dicer site of the miR-210 hairpin precursor. This interaction inhibits production of the mature miRNA, derepresses glycerol-3-phosphate dehydrogenase 1-like enzyme (GPD1L), a hypoxia-associated protein negatively regulated by miR-210, decreases HIF-1α, and triggers apoptosis of triple negative breast cancer cells only under hypoxic conditions. Further, Targapremir-210 inhibits tumorigenesis in a mouse xenograft model of hypoxic triple negative breast cancer. Many factors govern molecular recognition of biological targets by small molecules. For protein, chemoproteomics and activity-based protein profiling are invaluable tools to study small molecule target engagement and selectivity in cells. Such approaches are lacking for RNA, leaving a void in the understanding of its druggability. We applied Chemical Cross-Linking and Isolation by Pull Down (Chem-CLIP) to study the cellular selectivity and the on- and off-targets of Targapremir-210. Targapremir-210 selectively recognizes the miR-210 precursor and can differentially recognize RNAs in cells that have the same target motif but have different expression levels, revealing this important feature for selectively drugging RNAs for the first time. These studies show that small molecules can be rapidly designed to selectively target RNAs and affect cellular responses to environmental conditions, resulting in favorable benefits against cancer. Further, they help define rules for identifying druggable targets in the transcriptome.

  14. Allosteric “beta-blocker” isolated from a DNA-encoded small molecule library (United States)

    Ahn, Seungkirl; Kahsai, Alem W.; Pani, Biswaranjan; Wang, Qin-Ting; Zhao, Shuai; Wall, Alissa L.; Strachan, Ryan T.; Staus, Dean P.; Wingler, Laura M.; Sun, Lillian D.; Sinnaeve, Justine; Choi, Minjung; Cho, Ted; Xu, Thomas T.; Hansen, Gwenn M.; Burnett, Michael B.; Lamerdin, Jane E.; Bassoni, Daniel L.; Gavino, Bryant J.; Husemoen, Gitte; Olsen, Eva K.; Franch, Thomas; Costanzi, Stefano; Chen, Xin; Lefkowitz, Robert J.


    The β2-adrenergic receptor (β2AR) has been a model system for understanding regulatory mechanisms of G-protein–coupled receptor (GPCR) actions and plays a significant role in cardiovascular and pulmonary diseases. Because all known β-adrenergic receptor drugs target the orthosteric binding site of the receptor, we set out to isolate allosteric ligands for this receptor by panning DNA-encoded small-molecule libraries comprising 190 million distinct compounds against purified human β2AR. Here, we report the discovery of a small-molecule negative allosteric modulator (antagonist), compound 15 [([4-((2S)-3-(((S)-3-(3-bromophenyl)-1-(methylamino)-1-oxopropan-2-yl)amino)-2-(2-cyclohexyl-2-phenylacetamido)-3-oxopropyl)benzamide], exhibiting a unique chemotype and low micromolar affinity for the β2AR. Binding of 15 to the receptor cooperatively enhances orthosteric inverse agonist binding while negatively modulating binding of orthosteric agonists. Studies with a specific antibody that binds to an intracellular region of the β2AR suggest that 15 binds in proximity to the G-protein binding site on the cytosolic surface of the β2AR. In cell-signaling studies, 15 inhibits cAMP production through the β2AR, but not that mediated by other Gs-coupled receptors. Compound 15 also similarly inhibits β-arrestin recruitment to the activated β2AR. This study presents an allosteric small-molecule ligand for the β2AR and introduces a broadly applicable method for screening DNA-encoded small-molecule libraries against purified GPCR targets. Importantly, such an approach could facilitate the discovery of GPCR drugs with tailored allosteric effects. PMID:28130548

  15. Inhibition of SIRT1 by a small molecule induces apoptosis in breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Kalle, Arunasree M., E-mail: [Institute of Life Sciences, University of Hyderabad Campus, Hyderabad, AP 500 046 (India); Mallika, A. [Institute of Life Sciences, University of Hyderabad Campus, Hyderabad, AP 500 046 (India); Badiger, Jayasree [HKE' s Smt. V.G. College for Women, Aiwan-E-Shahi Area, Gulbarga, KA 585 102 (India); Alinakhi [Institute of Life Sciences, University of Hyderabad Campus, Hyderabad, AP 500 046 (India); Talukdar, Pinaki [Department of Chemistry, Indian Institute of Science Education and Research, First Floor, Central Tower, Sai Trinity Building Garware Circle, Sutarwadi, PashanPune, Maharashtra 411 021 (India); Sachchidanand [Lupin Research Park, 46/47, A, Village Nande, Taluka Mulshi, Dist. Pune 411 042 (India)


    Research highlights: {yields} Novel small molecule SIRT1 inhibitor better than sirtinol. {yields} IC{sub 50} 500 nM. {yields} Specific tumor cytotoxicity towards breast cancer cells. {yields} Restoration of H3K9 acetylation levels to baseline when co-treated with SIRT1 activator (Activator X) and inhibitor (ILS-JGB-1741). -- Abstract: Overexpression of SIRT1, a NAD{sup +}-dependent class III histone deacetylases (HDACs), is implicated in many cancers and therefore could become a promising antitumor target. Here we demonstrate a small molecule SIRT1 inhibitor, ILS-JGB-1741(JGB1741) with potent inhibitory effects on the proliferation of human metastatic breast cancer cells, MDA-MB 231. The molecule has been designed using medicinal chemistry approach based on known SIRT1 inhibitor, sirtinol. The molecule showed a significant inhibition of SIRT1 activity compared to sirtinol. Studies on the antitumor effects of JGB on three different cancer cell lines, K562, HepG2 and MDA-MB 231 showed an IC{sub 50} of 1, 10 and 0.5 {mu}M, respectively. Further studies on MDA-MB 231 cells showed a dose-dependent increase in K9 and K382 acetylation of H3 and p53, respectively. Results also demonstrated that JGB1741-induced apoptosis is associated with increase in cytochrome c release, modulation in Bax/Bcl2 ratio and cleavage of PARP. Flowcytometric analysis showed increased percentage of apoptotic cells, decrease in mitochondrial membrane potential and increase in multicaspase activation. In conclusion, the present study indicates the potent apoptotic effects of JGB1741 in MDA-MB 231 cells.

  16. Live-cell microscopy reveals small molecule inhibitor effects on MAPK pathway dynamics.

    Directory of Open Access Journals (Sweden)

    Daniel J Anderson

    Full Text Available Oncogenic mutations in the mitogen activated protein kinase (MAPK pathway are prevalent in human tumors, making this pathway a target of drug development efforts. Recently, ATP-competitive Raf inhibitors were shown to cause MAPK pathway activation via Raf kinase priming in wild-type BRaf cells and tumors, highlighting the need for a thorough understanding of signaling in the context of small molecule kinase inhibitors. Here, we present critical improvements in cell-line engineering and image analysis coupled with automated image acquisition that allow for the simultaneous identification of cellular localization of multiple MAPK pathway components (KRas, CRaf, Mek1 and Erk2. We use these assays in a systematic study of the effect of small molecule inhibitors across the MAPK cascade either as single agents or in combination. Both Raf inhibitor priming as well as the release from negative feedback induced by Mek and Erk inhibitors cause translocation of CRaf to the plasma membrane via mechanisms that are additive in pathway activation. Analysis of Erk activation and sub-cellular localization upon inhibitor treatments reveals differential inhibition and activation with the Raf inhibitors AZD628 and GDC0879 respectively. Since both single agent and combination studies of Raf and Mek inhibitors are currently in the clinic, our assays provide valuable insight into their effects on MAPK signaling in live cells.

  17. Adsorption of small gas molecules on B36 nanocluster

    Indian Academy of Sciences (India)

    Younes Valadbeigi; Hossein Farrokhpour; Mahmoud Tabrizchi


    Adsorption of CO, N2, H2O, O2, H2 and NO molecules on B36 cluster was studied using density functional theory (DFT) with B3LYP functional and 6-311+G(d,p) basis set. Energies, enthalpies and Gibbs free energies of the adsorption processes were calculated. The thermodynamic data showed that the B36 cluster is a good adsorbent only for CO, O2 and NO molecules. The calculated energies of adsorption of N2, H2 O and H2 on the B36 cluster were positive values. CO molecule is adsorbed via the carbon atom more effectively, while the nitrogen atom of NO is adsorbed better than the oxygen atom. Also, when NO and O2 are adsorbed synchronously via both atoms, they dissociate. The edge boron atoms of the B36 cluster showed more reactivity than the inner atoms.

  18. Biased small-molecule ligands for selective inhibition of HIV-1 cell entry via CCR5

    DEFF Research Database (Denmark)

    Berg, Christian; Spiess, Katja; von Lüttichau, Hans Rudolf;


    Since the discovery of HIV's use of CCR5 as the primary coreceptor in fusion, the focus on developing small-molecule receptor antagonists for inhibition hereof has only resulted in one single drug, Maraviroc. We therefore investigated the possibility of using small-molecule CCR5 agonists as HIV-1...

  19. Identification of small molecule inhibitors of phosphatidylinositol 3-kinase and autophagy

    DEFF Research Database (Denmark)

    Farkas, Thomas; Daugaard, Mads; Jaattela, Marja


    by the lack of specific small molecule inhibitors. Thus, we screened two small molecule kinase inhibitor libraries for inhibitors of rapamycin-induced autophagic flux. The three most potent inhibitors identified conferred profound inhibition of autophagic flux by inhibiting the formation of autophagosomes...

  20. Battle for the bulge: directing small molecules to DNA and RNA defects. (United States)

    Bevilacqua, Philip C


    Small molecules were tailored to specifically bind bulged DNA by complementing the geometry and nucleotide size of the bulge site. The prospect of generating small molecules that influence the secondary structure of DNA and RNA holds great promise for clinical applications.

  1. Group specific internal standard technology (GSIST) for simultaneous identification and quantification of small molecules (United States)

    Adamec, Jiri; Yang, Wen-Chu; Regnier, Fred E


    Reagents and methods are provided that permit simultaneous analysis of multiple diverse small molecule analytes present in a complex mixture. Samples are labeled with chemically identical but isotopically distince forms of the labeling reagent, and analyzed using mass spectrometry. A single reagent simultaneously derivatizes multiple small molecule analytes having different reactive functional groups.

  2. Protein kinase Calpha and epsilon small-molecule targeted therapeutics: a new roadmap to two Holy Grails in drug discovery? (United States)

    O'Brian, Catherine A; Chu, Feng; Bornmann, William G; Maxwell, David S


    Protein kinase (PK)Calpha and epsilon are rational targets for cancer therapy. However, targeted experimental therapeutics that inhibit PKCalpha or epsilon are unavailable. The authors established recently that covalent modification of an active-site cysteine in human PKCepsilon, Cys452, by small molecules, for example 2-mercaptoethanolamine, is necessary and sufficient to render PKCepsilon kinase-dead. Cys452 is conserved in only eleven human protein kinase genes, including PKCalpha. Therefore, the design of small molecules that bind PKC active sites with an electrophile substituent positioned proximal to the Cys452 side chain may lead to targeted therapeutics that selectively inhibit PKCepsilon, PKCalpha or other PKC isozymes.

  3. Quantifying small molecule phenotypic effects using mitochondrial morpho-functional fingerprinting and machine learning (United States)

    Blanchet, Lionel; Smeitink, Jan A. M.; van Emst-de Vries, Sjenet E.; Vogels, Caroline; Pellegrini, Mina; Jonckheere, An I.; Rodenburg, Richard J. T.; Buydens, Lutgarde M. C.; Beyrath, Julien; Willems, Peter H. G. M.; Koopman, Werner J. H.


    In primary fibroblasts from Leigh Syndrome (LS) patients, isolated mitochondrial complex I deficiency is associated with increased reactive oxygen species levels and mitochondrial morpho-functional changes. Empirical evidence suggests these aberrations constitute linked therapeutic targets for small chemical molecules. However, the latter generally induce multiple subtle effects, meaning that in vitro potency analysis or single-parameter high-throughput cell screening are of limited use to identify these molecules. We combine automated image quantification and artificial intelligence to discriminate between primary fibroblasts of a healthy individual and a LS patient based upon their mitochondrial morpho-functional phenotype. We then evaluate the effects of newly developed Trolox variants in LS patient cells. This revealed that Trolox ornithylamide hydrochloride best counterbalanced mitochondrial morpho-functional aberrations, effectively scavenged ROS and increased the maximal activity of mitochondrial complexes I, IV and citrate synthase. Our results suggest that Trolox-derived antioxidants are promising candidates in therapy development for human mitochondrial disorders.

  4. Dual Function Additives: A Small Molecule Crosslinker for Enhanced Efficiency and Stability in Organic Solar Cells

    KAUST Repository

    Rumer, Joseph W.


    A bis-azide-based small molecule crosslinker is synthesized and evaluated as both a stabilizing and efficiency-boosting additive in bulk heterojunction organic photovoltaic cells. Activated by a noninvasive and scalable solution processing technique, polymer:fullerene blends exhibit improved thermal stability with suppressed polymer skin formation at the cathode and frustrated fullerene aggregation on ageing, with initial efficiency increased from 6% to 7%. © 2015 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Water and oxygen induced degradation of small molecule organic solar cells

    DEFF Research Database (Denmark)

    Hermenau, Martin; Riede, Moritz; Leo, Karl


    Small molecule organic solar cells were studied with respect to water and oxygen induced degradation by mapping the spatial distribution of reaction products in order to elucidate the degradation patterns and failure mechanisms. The active layers consist of a 30 nm bulk heterojunction formed...... with isotopic labeling using H218O and 18O2 provided information on where and to what extent the atmosphere had reacted with the device. A comparison was made between the use of a humid (oxygen free) atmosphere, a dry oxygen atmosphere, and a dry (oxygen free) nitrogen atmosphere during testing of devices...

  6. Electrostatic potential of several small molecules from density functional theory

    Institute of Scientific and Technical Information of China (English)


    A number of density functional theory (DFT) methods were used to calculate the electrostatic potential for the series of molecules N2, F2, NH3, H2O, CHF3, CHCl3, C6H6, TiF4, CO(NH2)2 and C4H5N3O compared with QCISD (quadratic configuration interaction method including single and double substitutions) results. Comparisons were made between the DFT computed results and the QCISD ab initio ones and MP2 ab initio ones, compared with the root-mean-square deviation and electrostatic potential difference contours figures. It was found that the hybrid DFT method B3LYP, yields electrostatic potential in good agreement with the QCISD results. It is suggest this is a useful approach, especially for large molecules that are difficult to study by ab initio methods.

  7. Small Molecule Inhibitors of BAF; A Promising Family of Compounds in HIV-1 Latency Reversal

    Directory of Open Access Journals (Sweden)

    Mateusz Stoszko


    Full Text Available Persistence of latently infected cells in presence of Anti-Retroviral Therapy presents the main obstacle to HIV-1 eradication. Much effort is thus placed on identification of compounds capable of HIV-1 latency reversal in order to render infected cells susceptible to viral cytopathic effects and immune clearance. We identified the BAF chromatin remodeling complex as a key player required for maintenance of HIV-1 latency, highlighting its potential as a molecular target for inhibition in latency reversal. Here, we screened a recently identified panel of small molecule inhibitors of BAF (BAFi's for potential to activate latent HIV-1. Latency reversal was strongly induced by BAFi's Caffeic Acid Phenethyl Ester and Pyrimethamine, two molecules previously characterized for clinical application. BAFi's reversed HIV-1 latency in cell line based latency models, in two ex vivo infected primary cell models of latency, as well as in HIV-1 infected patient's CD4+ T cells, without inducing T cell proliferation or activation. BAFi-induced HIV-1 latency reversal was synergistically enhanced upon PKC pathway activation and HDAC-inhibition. Therefore BAFi's constitute a promising family of molecules for inclusion in therapeutic combinatorial HIV-1 latency reversal.

  8. Encapsulation of small ionic molecules within alpha-cyclodextrins. (United States)

    Rodriguez, Javier; Elola, M Dolores


    Results from molecular dynamics experiments pertaining to the encapsulation of ClO4- within the hydrophobic cavity of an aqueous alpha-cyclodextrin (alpha-CD) are presented. Using a biased sampling procedure, we constructed the Gibbs free energy profile associated with the complexation process. The profile presents a global minimum at the vicinity of the primary hydroxyl groups, where the ion remains tightly coordinated to four water molecules via hydrogen bonds. Our estimate for the global free energy of encapsulation yields DeltaGenc approximately -2.5 kBT. The decomposition of the average forces acting on the trapped ion reveals that the encapsulation is controlled by Coulomb interactions between the ion and OH groups in the CD, with a much smaller contribution from the solvent molecules. Changes in the previous results, arising from the partial methylation of the host CD and modifications in the charge distribution of the guest molecule are also discussed. The global picture that emerges from our results suggests that the stability of the ClO4- encapsulation involves not only the individual ion but also its first solvation shell.

  9. A blend of small molecules regulates both mating and development in Caenorhabditis elegans. (United States)

    Srinivasan, Jagan; Kaplan, Fatma; Ajredini, Ramadan; Zachariah, Cherian; Alborn, Hans T; Teal, Peter E A; Malik, Rabia U; Edison, Arthur S; Sternberg, Paul W; Schroeder, Frank C


    In many organisms, population-density sensing and sexual attraction rely on small-molecule-based signalling systems. In the nematode Caenorhabditis elegans, population density is monitored through specific glycosides of the dideoxysugar ascarylose (the 'ascarosides') that promote entry into an alternative larval stage, the non-feeding and highly persistent dauer stage. In addition, adult C. elegans males are attracted to hermaphrodites by a previously unidentified small-molecule signal. Here we show, by means of combinatorial activity-guided fractionation of the C. elegans metabolome, that the mating signal consists of a synergistic blend of three dauer-inducing ascarosides, which we call ascr#2, ascr#3 and ascr#4. This blend of ascarosides acts as a potent male attractant at very low concentrations, whereas at the higher concentrations required for dauer formation the compounds no longer attract males and instead deter hermaphrodites. The ascarosides ascr#2 and ascr#3 carry different, but overlapping, information, as ascr#3 is more potent as a male attractant than ascr#2, whereas ascr#2 is slightly more potent than ascr#3 in promoting dauer formation. We demonstrate that ascr#2, ascr#3 and ascr#4 are strongly synergistic, and that two types of neuron, the amphid single-ciliated sensory neuron type K (ASK) and the male-specific cephalic companion neuron (CEM), are required for male attraction by ascr#3. On the basis of these results, male attraction and dauer formation in C. elegans appear as alternative behavioural responses to a common set of signalling molecules. The ascaroside signalling system thus connects reproductive and developmental pathways and represents a unique example of structure- and concentration-dependent differential activity of signalling molecules.

  10. Dichotomy of cellular inhibition by small-molecule inhibitors revealed by single-cell analysis (United States)

    Vogel, Robert M.; Erez, Amir; Altan-Bonnet, Grégoire


    Despite progress in drug development, a quantitative and physiological understanding of how small-molecule inhibitors act on cells is lacking. Here, we measure the signalling and proliferative response of individual primary T-lymphocytes to a combination of antigen, cytokine and drug. We uncover two distinct modes of signalling inhibition: digital inhibition (the activated fraction of cells diminishes upon drug treatment, but active cells appear unperturbed), versus analogue inhibition (the activated fraction is unperturbed whereas activation response is diminished). We introduce a computational model of the signalling cascade that accounts for such inhibition dichotomy, and test the model predictions for the phenotypic variability of cellular responses. Finally, we demonstrate that the digital/analogue dichotomy of cellular response as revealed on short (signal transduction) timescales, translates into similar dichotomy on longer (proliferation) timescales. Our single-cell analysis of drug action illustrates the strength of quantitative approaches to translate in vitro pharmacology into functionally relevant cellular settings. PMID:27687249

  11. Small molecule and peptide-mediated inhibition of Epstein-Barr virus nuclear antigen 1 dimerization

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sun Young; Song, Kyung-A [Samsung Advanced Institute for Health Sciences and Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Samsung Biomedical Research Institute (SBRI), Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kieff, Elliott [Department of Medicine, Brigham and Women' s Hospital and Harvard Medical School, Boston, MA 02115 (United States); Kang, Myung-Soo, E-mail: [Samsung Advanced Institute for Health Sciences and Technology (SAIHST), Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Samsung Biomedical Research Institute (SBRI), Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Department of Medicine, Brigham and Women' s Hospital and Harvard Medical School, Boston, MA 02115 (United States)


    Highlights: Black-Right-Pointing-Pointer Evidence that targeting EBNA1 dimer, an EBV onco-antigen, can be achievable. Black-Right-Pointing-Pointer A small molecule and a peptide as EBNA1 dimerization inhibitors identified. Black-Right-Pointing-Pointer Both inhibitors associated with EBNA1 and blocked EBNA1 DNA binding activity. Black-Right-Pointing-Pointer Also, prevented its dimerization, and repressed viral gene transcription. -- Abstract: Latent Epstein-Barr virus (EBV) infection is associated with human B cell lymphomas and certain carcinomas. EBV episome persistence, replication, and gene expression are dependent on EBV-encoded nuclear antigen 1 (EBNA1)'s DNA binding domain (DBD)/dimerization domain (DD)-mediated sequence-specific DNA binding activity. Homodimerization of EBNA1 is essential for EBNA1 DNA binding and transactivation. In this study, we characterized a novel small molecule EBNA1 inhibitor EiK1, screened from the previous high throughput screening (HTS). The EiK1 compound specifically inhibited the EBNA1-dependent, OriP-enhanced transcription, but not EBNA1-independent transcription. A Surface Plasmon Resonance Biacore assay revealed that EiK1 associates with EBNA1 amino acid 459-607 DBD/DD. Consistent with the SPR data, in vitro gel shift assays showed that EiK1 suppressed the activity of EBNA1 binding to the cognate familial repeats (FR) sequence, but not control RBP-J{kappa} binding to the J{kappa} site. Subsequently, a cross-linker-mediated in vitro multimerization assay and EBNA1 homodimerization-dependent yeast two-hybrid assay showed that EiK1 significantly inhibited EBNA1 dimerization. In an attempt to identify more highly specific peptide inhibitors, small peptides encompassing the EBNA1 DBD/DD were screened for inhibition of EBNA1 DBD-mediated DNA binding function. The small peptide P85, covering EBNA1 a.a. 560-574, significantly blocked EBNA1 DNA binding activity in vitro, prevented dimerization in vitro and in vivo, associated

  12. Mapping the Protein Interaction Landscape for Fully Functionalized Small-Molecule Probes in Human Cells


    Kambe, Tohru; Correia, Bruno E.; Niphakis, Micah J.; Cravatt, Benjamin F.


    Phenotypic screening provides a means to discover small molecules that perturb cell biological processes. Discerning the proteins and biochemical pathways targeted by screening hits, however, remains technically challenging. We recently described the use of small molecules bearing photoreactive groups and latent affinity handles as fully functionalized probes for integrated phenotypic screening and target identification. The general utility of such probes, or, for that matter, any small-molec...

  13. Targeted delivery as key for the success of small osteoinductive molecules. (United States)

    Balmayor, Elizabeth R


    Molecules such as growth factors, peptides and small molecules can guide cellular behavior and are thus important for tissue engineering. They are rapidly emerging as promising compounds for the regeneration of tissues of the musculoskeletal system. Growth factors have disadvantages such as high cost, short half-life, supraphysiological amounts needed, etc. Therefore, small molecules may be an alternative. These molecules have been discovered using high throughput screening. Small osteoinductive molecules exhibit several advantages over growth factors owing to their small sizes, such as high stability and non-immunogenicity. These molecules may stimulate directly signaling pathways that are important for osteogenesis. However, systemic application doesn't induce osteogenesis in most cases. Therefore, local administration is needed. This may be achieved by using a bone graft material providing additional osteoconductive properties. These graft materials can also act by themselves as a delivery matrix for targeted and local delivery. Furthermore, vascularization is necessary in the process of osteogenesis. Many of the small molecules are also capable of promoting vascularization of the tissue to be regenerated. Thus, in this review, special attention is given to molecules that are capable of inducing both angiogenesis and osteogenesis simultaneously. Finally, more recent preclinical and clinical uses in bone regeneration of those molecules are described, highlighting the needs for the clinical translation of these promising compounds.

  14. Studying small molecule-aptamer interactions using MicroScale Thermophoresis (MST). (United States)

    Entzian, Clemens; Schubert, Thomas


    Aptamers are potent and versatile binding molecules recognizing various classes of target molecules. Even challenging targets such as small molecules can be identified and bound by aptamers. Studying the interaction between aptamers and drugs, antibiotics or metabolites in detail is however difficult due to the lack of sophisticated analysis methods. Basic binding parameters of these small molecule-aptamer interactions such as binding affinity, stoichiometry and thermodynamics are elaborately to access using the state of the art technologies. The innovative MicroScale Thermophoresis (MST) is a novel, rapid and precise method to characterize these small molecule-aptamer interactions in solution at microliter scale. The technology is based on the movement of molecules through temperature gradients, a physical effect referred to as thermophoresis. The thermophoretic movement of a molecule depends - besides on its size - on charge and hydration shell. Upon the interaction of a small molecule and an aptamer, at least one of these parameters is altered, leading to a change in the movement behavior, which can be used to quantify molecular interactions independent of the size of the target molecule. The MST offers free choice of buffers, even measurements in complex bioliquids are possible. The dynamic affinity range covers the pM to mM range and is therefore perfectly suited to analyze small molecule-aptamer interactions. This section describes a protocol how quantitative binding parameters for aptamer-small molecule interactions can be obtained by MST. This is demonstrated by mapping down the binding site of the well-known ATP aptamer DH25.42 to a specific region at the adenine of the ATP molecule.

  15. Rational design and characterization of a Rac GTPase-specific small molecule inhibitor. (United States)

    Gao, Yuan; Dickerson, J Bradley; Guo, Fukun; Zheng, Jie; Zheng, Yi


    The signaling pathways mediated by Rho family GTPases have been implicated in many aspects of cell biology. The specificity of the pathways is achieved in part by the selective interaction between Dbl family guanine nucleotide exchange factors (GEFs) and their Rho GTPase substrates. Here, we report a first-generation small-molecule inhibitor of Rac GTPase targeting Rac activation by GEF. The chemical compound NSC23766 was identified by a structure-based virtual screening of compounds that fit into a surface groove of Rac1 known to be critical for GEF specification. In vitro it could effectively inhibit Rac1 binding and activation by the Rac-specific GEF Trio or Tiam1 in a dose-dependent manner without interfering with the closely related Cdc42 or RhoA binding or activation by their respective GEFs or with Rac1 interaction with BcrGAP or effector PAK1. In cells, it potently blocked serum or platelet-derived growth factor-induced Rac1 activation and lamellipodia formation without affecting the activity of endogenous Cdc42 or RhoA. Moreover, this compound reduced Trio or Tiam1 but not Vav, Lbc, Intersectin, or a constitutively active Rac1 mutant-stimulated cell growth and suppressed Trio, Tiam1, or Ras-induced cell transformation. When applied to human prostate cancer PC-3 cells, it was able to inhibit the proliferation, anchorage-independent growth and invasion phenotypes that require the endogenous Rac1 activity. Thus, NSC23766 constitutes a Rac-specific small-molecule inhibitor that could be useful to study the role of Rac in various cellular functions and to reverse tumor cell phenotypes associated with Rac deregulation.

  16. Novel approaches for single molecule activation and detection

    CERN Document Server

    Benfenati, Fabio; Torre, Vincent


    How can we obtain tools able to process and exchange information at the molecular scale In order to do this, it is necessary to activate and detect single molecules under controlled conditions. This book focuses on the generation of biologically-inspired molecular devices. These devices are based on the developments of new photonic tools able to activate and stimulate single molecule machines. Additionally, new light sensitive molecules can be selectively activated by photonic tools. These technological innovations will provide a way to control activation of single light-sensitive molecules, a

  17. Structural Design Principle of Small-Molecule Organic Semiconductors for Metal-Free, Visible-Light-Promoted Photocatalysis. (United States)

    Wang, Lei; Huang, Wei; Li, Run; Gehrig, Dominik; Blom, Paul W M; Landfester, Katharina; Zhang, Kai A I


    Herein, we report on the structural design principle of small-molecule organic semiconductors as metal-free, pure organic and visible light-active photocatalysts. Two series of electron-donor and acceptor-type organic semiconductor molecules were synthesized to meet crucial requirements, such as 1) absorption range in the visible region, 2) sufficient photoredox potential, and 3) long lifetime of photogenerated excitons. The photocatalytic activity was demonstrated in the intermolecular C-H functionalization of electron-rich heteroaromates with malonate derivatives. A mechanistic study of the light-induced electron transport between the organic photocatalyst, substrate, and the sacrificial agent are described. With their tunable absorption range and defined energy-band structure, the small-molecule organic semiconductors could offer a new class of metal-free and visible light-active photocatalysts for chemical reactions.

  18. Connecting synthetic chemistry decisions to cell and genome biology using small-molecule phenotypic profiling. (United States)

    Wagner, Bridget K; Clemons, Paul A


    Discovering small-molecule modulators for thousands of gene products requires multiple stages of biological testing, specificity evaluation, and chemical optimization. Many cellular profiling methods, including cellular sensitivity, gene expression, and cellular imaging, have emerged as methods to assess the functional consequences of biological perturbations. Cellular profiling methods applied to small-molecule science provide opportunities to use complex phenotypic information to prioritize and optimize small-molecule structures simultaneously against multiple biological endpoints. As throughput increases and cost decreases for such technologies, we see an emerging paradigm of using more information earlier in probe-discovery and drug-discovery efforts. Moreover, increasing access to public datasets makes possible the construction of 'virtual' profiles of small-molecule performance, even when multiplexed measurements were not performed or when multidimensional profiling was not the original intent. We review some key conceptual advances in small-molecule phenotypic profiling, emphasizing connections to other information, such as protein-binding measurements, genetic perturbations, and cell states. We argue that to maximally leverage these measurements in probe-discovery and drug-discovery requires a fundamental connection to synthetic chemistry, allowing the consequences of synthetic decisions to be described in terms of changes in small-molecule profiles. Mining such data in the context of chemical structure and synthesis strategies can inform decisions about chemistry procurement and library development, leading to optimal small-molecule screening collections.

  19. Recent advances in inorganic materials for LDI-MS analysis of small molecules. (United States)

    Shi, C Y; Deng, C H


    In this review, various inorganic materials were summarized for the analysis of small molecules by laser desorption/ionization mass spectrometry (LDI-MS). Due to its tremendous advantages, such as simplicity, high speed, high throughput, small analyte volumes and tolerance towards salts, LDI-MS has been widely used in various analytes. During the ionization process, a suitable agent is required to assist the ionization, such as an appropriate matrix for matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS). However, it is normally difficult to analyze small molecules with the MALDI technique because conventional organic matrices may produce matrix-related peaks in the low molecular-weight region, which limits the detection of small molecules (m/z molecules. These inorganic materials can transfer energy and improve the ionization efficiency of analytes. In addition, functionalized inorganic materials can act as both an adsorbent and an agent in the enrichment and ionization of small molecules. In this review, we mainly focus on present advances in inorganic materials for the LDI-MS analysis of small molecules in the last five years, which contains the synthetic protocols of novel inorganic materials and the detailed results achieved by inorganic materials. On the other hand, this review also summarizes the application of inorganic materials as adsorbents in the selective enrichment of small molecules, which provides a new field for the application of inorganic materials.

  20. Small-molecule quinolinol inhibitor identified provides protection against BoNT/A in mice.

    Directory of Open Access Journals (Sweden)

    Padma Singh

    Full Text Available Botulinum neurotoxins (BoNTs, etiological agents of the life threatening neuroparalytic disease botulism, are the most toxic substances currently known. The potential for the use as bioweapon makes the development of small-molecule inhibitor against these deadly toxins is a top priority. Currently, there are no approved pharmacological treatments for BoNT intoxication. Although an effective vaccine/immunotherapy is available for immuno-prophylaxis but this cannot reverse the effects of toxin inside neurons. A small-molecule pharmacological intervention, especially one that would be effective against the light chain protease, would be highly desirable. Similarity search was carried out from ChemBridge and NSC libraries to the hit (7-(phenyl(8-quinolinylaminomethyl-8-quinolinol; NSC 84096 to mine its analogs. Several hits obtained were screened for in silico inhibition using AutoDock 4.1 and 19 new molecules selected based on binding energy and Ki. Among these, eleven quinolinol derivatives potently inhibited in vitro endopeptidase activity of botulinum neurotoxin type A light chain (rBoNT/A-LC on synaptosomes isolated from rat brain which simulate the in vivo system. Five of these inhibitor molecules exhibited IC(50 values ranging from 3.0 nM to 10.0 µM. NSC 84087 is the most potent inhibitor reported so far, found to be a promising lead for therapeutic development, as it exhibits no toxicity, and is able to protect animals from pre and post challenge of botulinum neurotoxin type A (BoNT/A.

  1. Dissociative chemisorption dynamics of small molecules on metal surfaces

    Institute of Scientific and Technical Information of China (English)

    JIANG Bin; XIE DaiQian


    Much progress has been achieved for both experimental and theoretical studies on the dissociative chemisorption of molecules on surfaces.Quantum state-resolved experimental data has provided unprecedented details for these fundamental steps in heterogeneous catalysis,while the quantitative dynamics is still not fully understood in theory.An in-depth understanding of experimental observations relies on accurate dynamical calculations,in which the potential energy surface and adequate quantum mechanical implementation are desired.This article summarizes the current methodologies on the construction of potential energy surfaces and the quantum mechanical treatments,some of which are promising for future applications.The challenges in this field are also addressed.

  2. High Speed Development and Synthesis of Novel Small Molecule Libraries

    Institute of Scientific and Technical Information of China (English)

    XIAO; Xiao-Yi


    Combinatorial chemistry has produced libraries of millions of compounds in the last decade. Screening of those compounds, unfortunately, has not yet yielded as many new drug candidates as initially expected. Among a number of possible reasons, one is that many libraries combinatorial chemistry produced in the early periods are of the nature of linear, flat, and flexible molecules such as peptides and oligonucleotides, which do not have the desired properties to selectively interact with their targets to yield high quality hits and leads. In order to increase the number of quality hits and leads, rigid, structural featurerich and drug-like compound libraries are highly desirable. Design and development of structural features-rich and natural product-like combinatorial libraries, as well as high speed library production using modern solution and solid phase synthesis techniques such as IRORI's Directed Sorting technology, will be discussed.  ……

  3. High Speed Development and Synthesis of Novel Small Molecule Libraries

    Institute of Scientific and Technical Information of China (English)


    @@ Combinatorial chemistry has produced libraries of millions of compounds in the last decade. Screening of those compounds, unfortunately, has not yet yielded as many new drug candidates as initially expected. Among a number of possible reasons, one is that many libraries combinatorial chemistry produced in the early periods are of the nature of linear, flat, and flexible molecules such as peptides and oligonucleotides, which do not have the desired properties to selectively interact with their targets to yield high quality hits and leads. In order to increase the number of quality hits and leads, rigid, structural featurerich and drug-like compound libraries are highly desirable. Design and development of structural features-rich and natural product-like combinatorial libraries, as well as high speed library production using modern solution and solid phase synthesis techniques such as IRORI's Directed Sorting technology, will be discussed.

  4. Identification of potential small molecule binding pockets on Rho family GTPases.

    Directory of Open Access Journals (Sweden)

    Juan Manuel Ortiz-Sanchez

    Full Text Available Rho GTPases are conformational switches that control a wide variety of signaling pathways critical for eukaryotic cell development and proliferation. They represent attractive targets for drug design as their aberrant function and deregulated activity is associated with many human diseases including cancer. Extensive high-resolution structures (>100 and recent mutagenesis studies have laid the foundation for the design of new structure-based chemotherapeutic strategies. Although the inhibition of Rho signaling with drug-like compounds is an active area of current research, very little attention has been devoted to directly inhibiting Rho by targeting potential allosteric non-nucleotide binding sites. By avoiding the nucleotide binding site, compounds may minimize the potential for undesirable off-target interactions with other ubiquitous GTP and ATP binding proteins. Here we describe the application of molecular dynamics simulations, principal component analysis, sequence conservation analysis, and ensemble small-molecule fragment mapping to provide an extensive mapping of potential small-molecule binding pockets on Rho family members. Characterized sites include novel pockets in the vicinity of the conformationaly responsive switch regions as well as distal sites that appear to be related to the conformations of the nucleotide binding region. Furthermore the use of accelerated molecular dynamics simulation, an advanced sampling method that extends the accessible time-scale of conventional simulations, is found to enhance the characterization of novel binding sites when conformational changes are important for the protein mechanism.

  5. Identification of Small Molecule Modulators of MicroRNA by Library Screening. (United States)

    Xiao, Zhangang; Chen, Yangchao


    MicroRNAs (miRNAs) function as oncogenes or tumor suppressors and are dysregulated in cancer. miRNAs therefore represent promising therapeutic targets for cancer. Small molecules that could modulate the expression of miRNAs would thus have potential as anticancer agents. Library screening of small molecules targeting miRNAs is a useful technology platform for anticancer drug development. Here, we describe a hepatocellular carcinoma (HCC) cell-based luciferase reporter system which could be used to screen for small molecule modulators of tumor suppressor microRNA-34a.

  6. Identification of a new class of small molecules that efficiently reactivate latent Epstein-Barr Virus. (United States)

    Tikhmyanova, Nadezhda; Schultz, David C; Lee, Theresa; Salvino, Joseph M; Lieberman, Paul M


    Epstein-Barr Virus (EBV) persists as a latent infection in many lymphoid and epithelial malignancies, including Burkitt's lymphomas, nasopharyngeal carcinomas, and gastric carcinomas. Current chemotherapeutic treatments of EBV-positive cancers include broad-spectrum cytotoxic drugs that ignore the EBV-positive status of tumors. An alternative strategy, referred to as oncolytic therapy, utilizes drugs that stimulate reactivation of latent EBV to enhance the selective killing of EBV-positive tumors, especially in combination with existing inhibitors of herpesvirus lytic replication, like Ganciclovir (GCV). At present, no small molecule, including histone deacetylase (HDAC) inhibitors, have proven safe or effective in clinical trials for treatment of EBV-positive cancers. Aiming to identify new chemical entities that induce EBV lytic cycle, we have developed a robust high-throughput cell-based assay to screen 66,840 small molecule compounds. Five structurally related tetrahydrocarboline derivatives were identified, two of which had EC50 measurements in the range of 150-170 nM. We show that these compounds reactivate EBV lytic markers ZTA and EA-D in all EBV-positive cell lines we have tested independent of the type of latency. The compounds reactivate a higher percentage of latently infected cells than HDAC inhibitors or phorbol esters in many cell types. The most active compounds showed low toxicity to EBV-negative cells but were highly effective at selective cell killing of EBV-positive cells when combined with GCV. We conclude that we have identified a class of small molecule compounds that are highly effective at reactivating latent EBV infection in a variety of cell types and show promise for lytic therapy in combination with GCV.

  7. Modulation of heat shock transcription factor 1 as a therapeutic target for small molecule intervention in neurodegenerative disease.

    Directory of Open Access Journals (Sweden)

    Daniel W Neef


    Full Text Available Neurodegenerative diseases such as Huntington disease are devastating disorders with no therapeutic approaches to ameliorate the underlying protein misfolding defect inherent to poly-glutamine (polyQ proteins. Given the mounting evidence that elevated levels of protein chaperones suppress polyQ protein misfolding, the master regulator of protein chaperone gene transcription, HSF1, is an attractive target for small molecule intervention. We describe a humanized yeast-based high-throughput screen to identify small molecule activators of human HSF1. This screen is insensitive to previously characterized activators of the heat shock response that have undesirable proteotoxic activity or that inhibit Hsp90, the central chaperone for cellular signaling and proliferation. A molecule identified in this screen, HSF1A, is structurally distinct from other characterized small molecule human HSF1 activators, activates HSF1 in mammalian and fly cells, elevates protein chaperone expression, ameliorates protein misfolding and cell death in polyQ-expressing neuronal precursor cells and protects against cytotoxicity in a fly model of polyQ-mediated neurodegeneration. In addition, we show that HSF1A interacts with components of the TRiC/CCT complex, suggesting a potentially novel regulatory role for this complex in modulating HSF1 activity. These studies describe a novel approach for the identification of new classes of pharmacological interventions for protein misfolding that underlies devastating neurodegenerative disease.

  8. Developing an Efficient and General Strategy for Immobilization of Small Molecules onto Microarrays Using Isocyanate Chemistry. (United States)

    Zhu, Chenggang; Zhu, Xiangdong; Landry, James P; Cui, Zhaomeng; Li, Quanfu; Dang, Yongjun; Mi, Lan; Zheng, Fengyun; Fei, Yiyan


    Small-molecule microarray (SMM) is an effective platform for identifying lead compounds from large collections of small molecules in drug discovery, and efficient immobilization of molecular compounds is a pre-requisite for the success of such a platform. On an isocyanate functionalized surface, we studied the dependence of immobilization efficiency on chemical residues on molecular compounds, terminal residues on isocyanate functionalized surface, lengths of spacer molecules, and post-printing treatment conditions, and we identified a set of optimized conditions that enable us to immobilize small molecules with significantly improved efficiencies, particularly for those molecules with carboxylic acid residues that are known to have low isocyanate reactivity. We fabricated microarrays of 3375 bioactive compounds on isocyanate functionalized glass slides under these optimized conditions and confirmed that immobilization percentage is over 73%.

  9. Developing an Efficient and General Strategy for Immobilization of Small Molecules onto Microarrays Using Isocyanate Chemistry (United States)

    Zhu, Chenggang; Zhu, Xiangdong; Landry, James P.; Cui, Zhaomeng; Li, Quanfu; Dang, Yongjun; Mi, Lan; Zheng, Fengyun; Fei, Yiyan


    Small-molecule microarray (SMM) is an effective platform for identifying lead compounds from large collections of small molecules in drug discovery, and efficient immobilization of molecular compounds is a pre-requisite for the success of such a platform. On an isocyanate functionalized surface, we studied the dependence of immobilization efficiency on chemical residues on molecular compounds, terminal residues on isocyanate functionalized surface, lengths of spacer molecules, and post-printing treatment conditions, and we identified a set of optimized conditions that enable us to immobilize small molecules with significantly improved efficiencies, particularly for those molecules with carboxylic acid residues that are known to have low isocyanate reactivity. We fabricated microarrays of 3375 bioactive compounds on isocyanate functionalized glass slides under these optimized conditions and confirmed that immobilization percentage is over 73%. PMID:26999137

  10. Developing an Efficient and General Strategy for Immobilization of Small Molecules onto Microarrays Using Isocyanate Chemistry

    Directory of Open Access Journals (Sweden)

    Chenggang Zhu


    Full Text Available Small-molecule microarray (SMM is an effective platform for identifying lead compounds from large collections of small molecules in drug discovery, and efficient immobilization of molecular compounds is a pre-requisite for the success of such a platform. On an isocyanate functionalized surface, we studied the dependence of immobilization efficiency on chemical residues on molecular compounds, terminal residues on isocyanate functionalized surface, lengths of spacer molecules, and post-printing treatment conditions, and we identified a set of optimized conditions that enable us to immobilize small molecules with significantly improved efficiencies, particularly for those molecules with carboxylic acid residues that are known to have low isocyanate reactivity. We fabricated microarrays of 3375 bioactive compounds on isocyanate functionalized glass slides under these optimized conditions and confirmed that immobilization percentage is over 73%.

  11. Discovery and demonstration of small circular DNA molecules derived from Chinese tomato yellow leaf curl virus

    Institute of Scientific and Technical Information of China (English)


    Tomato yellow leaf curl viruses belong to Begomoviruses of geminiviruses.In this work, we first found and demonstrated that the small circular DNA molecules were derived from Chinese tomato yellow leaf curl viruses (TYLCV-CHI).These small circular DNA molecules are about 1.3 kb, which are half the full-length of TYLCV-CHI DNA A.It was shown by sequence determination and analysis that there was unknown-origin sequence insertion in the middle of the small molecules.These sequences of unknown-origin were neither homologous to DNA A nor to DNA B, and were formed by recombination of virus DNA and plant DNA.Although various defective molecules contained different unknown-origin sequence insertion, all the molecules contained the intergenic region and part of the AC1(Rep) gene.But they did not contain full ORF.

  12. A small-molecule dye for NIR-II imaging. (United States)

    Antaris, Alexander L; Chen, Hao; Cheng, Kai; Sun, Yao; Hong, Guosong; Qu, Chunrong; Diao, Shuo; Deng, Zixin; Hu, Xianming; Zhang, Bo; Zhang, Xiaodong; Yaghi, Omar K; Alamparambil, Zita R; Hong, Xuechuan; Cheng, Zhen; Dai, Hongjie


    Fluorescent imaging of biological systems in the second near-infrared window (NIR-II) can probe tissue at centimetre depths and achieve micrometre-scale resolution at depths of millimetres. Unfortunately, all current NIR-II fluorophores are excreted slowly and are largely retained within the reticuloendothelial system, making clinical translation nearly impossible. Here, we report a rapidly excreted NIR-II fluorophore (∼90% excreted through the kidneys within 24 h) based on a synthetic 970-Da organic molecule (CH1055). The fluorophore outperformed indocyanine green (ICG)-a clinically approved NIR-I dye-in resolving mouse lymphatic vasculature and sentinel lymphatic mapping near a tumour. High levels of uptake of PEGylated-CH1055 dye were observed in brain tumours in mice, suggesting that the dye was detected at a depth of ∼4 mm. The CH1055 dye also allowed targeted molecular imaging of tumours in vivo when conjugated with anti-EGFR Affibody. Moreover, a superior tumour-to-background signal ratio allowed precise image-guided tumour-removal surgery.

  13. A small-molecule dye for NIR-II imaging (United States)

    Antaris, Alexander L.; Chen, Hao; Cheng, Kai; Sun, Yao; Hong, Guosong; Qu, Chunrong; Diao, Shuo; Deng, Zixin; Hu, Xianming; Zhang, Bo; Zhang, Xiaodong; Yaghi, Omar K.; Alamparambil, Zita R.; Hong, Xuechuan; Cheng, Zhen; Dai, Hongjie


    Fluorescent imaging of biological systems in the second near-infrared window (NIR-II) can probe tissue at centimetre depths and achieve micrometre-scale resolution at depths of millimetres. Unfortunately, all current NIR-II fluorophores are excreted slowly and are largely retained within the reticuloendothelial system, making clinical translation nearly impossible. Here, we report a rapidly excreted NIR-II fluorophore (~90% excreted through the kidneys within 24 h) based on a synthetic 970-Da organic molecule (CH1055). The fluorophore outperformed indocyanine green (ICG)--a clinically approved NIR-I dye--in resolving mouse lymphatic vasculature and sentinel lymphatic mapping near a tumour. High levels of uptake of PEGylated-CH1055 dye were observed in brain tumours in mice, suggesting that the dye was detected at a depth of ~4 mm. The CH1055 dye also allowed targeted molecular imaging of tumours in vivo when conjugated with anti-EGFR Affibody. Moreover, a superior tumour-to-background signal ratio allowed precise image-guided tumour-removal surgery.

  14. Identification of Novel Small Molecule Inhibitors of Oncogenic RET Kinase


    Marialuisa Moccia; Qingsong Liu; Teresa Guida; Giorgia Federico; Annalisa Brescia; Zheng Zhao; Hwan Geun Choi; Xianming Deng; Li Tan; Jinhua Wang; Marc Billaud; Gray, Nathanael S.; Francesca Carlomagno; Massimo Santoro


    Oncogenic mutation of the RET receptor tyrosine kinase is observed in several human malignancies. Here, we describe three novel type II RET tyrosine kinase inhibitors (TKI), ALW-II-41-27, XMD15-44 and HG-6-63-01, that inhibit the cellular activity of oncogenic RET mutants at two digit nanomolar concentration. These three compounds shared a 3-trifluoromethyl-4-methylpiperazinephenyl pharmacophore that stabilizes the 'DFG-out' inactive conformation of RET activation loop. They blocked RET-media...

  15. Matrix Infrared Spectroscopic and Computational Investigations of Novel Small Uranium Containing Molecules - Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, Lester


    Direct reactions of f-element uranium, thorium and lanthanide metal atoms were investigated with small molecules. These metal atoms were generated by laser ablation and mixed with the reagent molecules then condensed with noble gases at 4K. The products were analyzed by absorption of infrared light to measure vibrational frequencies which were confirmed by quantum chemical calculations. We have learned more about the reactivity of uranium atoms with common molecules, which will aid in the develolpment of further applications of uranium.

  16. Novel patient cell-based HTS assay for identification of small molecules for a lysosomal storage disease.

    Directory of Open Access Journals (Sweden)

    Haifeng Geng

    Full Text Available Small molecules have been identified as potential therapeutic agents for lysosomal storage diseases (LSDs, inherited metabolic disorders caused by defects in proteins that result in lysosome dysfunctional. Some small molecules function assisting the folding of mutant misfolded lysosomal enzymes that are otherwise degraded in ER-associated degradation. The ultimate result is the enhancement of the residual enzymatic activity of the deficient enzyme. Most of the high throughput screening (HTS assays developed to identify these molecules are single-target biochemical assays. Here we describe a cell-based assay using patient cell lines to identify small molecules that enhance the residual arylsulfatase A (ASA activity found in patients with metachromatic leukodystrophy (MLD, a progressive neurodegenerative LSD. In order to generate sufficient cell lines for a large scale HTS, primary cultured fibroblasts from MLD patients were transformed using SV40 large T antigen. These SV40 transformed (SV40t cells showed to conserve biochemical characteristics of the primary cells. Using a specific colorimetric substrate para-nitrocatechol sulfate (pNCS, detectable ASA residual activity were observed in primary and SV40t fibroblasts from a MLD patient (ASA-I179S cultured in multi-well plates. A robust fluorescence ASA assay was developed in high-density 1,536-well plates using the traditional colorimetric pNCS substrate, whose product (pNC acts as "plate fluorescence quencher" in white solid-bottom plates. The quantitative cell-based HTS assay for ASA generated strong statistical parameters when tested against a diverse small molecule collection. This cell-based assay approach can be used for several other LSDs and genetic disorders, especially those that rely on colorimetric substrates which traditionally present low sensitivity for assay-miniaturization. In addition, the quantitative cell-based HTS assay here developed using patient cells creates an

  17. Synthesis of many different types of organic small molecules using one automated process. (United States)

    Li, Junqi; Ballmer, Steven G; Gillis, Eric P; Fujii, Seiko; Schmidt, Michael J; Palazzolo, Andrea M E; Lehmann, Jonathan W; Morehouse, Greg F; Burke, Martin D


    Small-molecule synthesis usually relies on procedures that are highly customized for each target. A broadly applicable automated process could greatly increase the accessibility of this class of compounds to enable investigations of their practical potential. Here we report the synthesis of 14 distinct classes of small molecules using the same fully automated process. This was achieved by strategically expanding the scope of a building block-based synthesis platform to include even C(sp3)-rich polycyclic natural product frameworks and discovering a catch-and-release chromatographic purification protocol applicable to all of the corresponding intermediates. With thousands of compatible building blocks already commercially available, many small molecules are now accessible with this platform. More broadly, these findings illuminate an actionable roadmap to a more general and automated approach for small-molecule synthesis.

  18. Biomedical application of MALDI mass spectrometry for small-molecule analysis

    NARCIS (Netherlands)

    Kampen, J.J. van; Burgers, P.C.; Groot, R. de; Gruters, R.A.; Luider, T.M.


    Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is an emerging analytical tool for the analysis of molecules with molar masses below 1,000 Da; that is, small molecules. This technique offers rapid analysis, high sensitivity, low sample consumption, a relative high toleranc

  19. Optimized Distributed Feedback Dye Laser Sensor for Real-Time Monitoring of Small Molecule Diffusion

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Smith, Cameron; Dufva, Martin;


    parameter for optimization. Using such laser sensors in an imaging spectroscopy setup, real-time label-free monitoring of sugar molecule diffusion in water is demonstrated. This method could potentially pave the way towards the analysis of small molecule diffusion in various media, e.g. protein signaling...... processes in tissue....

  20. Synthesis, Optimization, and Evaluation of Novel Small Molecules as Antagonists of WDR5-MLL Interaction. (United States)

    Bolshan, Yuri; Getlik, Matthäus; Kuznetsova, Ekaterina; Wasney, Gregory A; Hajian, Taraneh; Poda, Gennadiy; Nguyen, Kong T; Wu, Hong; Dombrovski, Ludmila; Dong, Aiping; Senisterra, Guillermo; Schapira, Matthieu; Arrowsmith, Cheryl H; Brown, Peter J; Al-Awar, Rima; Vedadi, Masoud; Smil, David


    The WD40-repeat protein WDR5 plays a critical role in maintaining the integrity of MLL complexes and fully activating their methyltransferase function. MLL complexes, the trithorax-like family of SET1 methyltransferases, catalyze trimethylation of lysine 4 on histone 3, and they have been widely implicated in various cancers. Antagonism of WDR5 and MLL subunit interaction by small molecules has recently been presented as a practical way to inhibit activity of the MLL1 complex, and N-(2-(4-methylpiperazin-1-yl)-5-substituted-phenyl) benzamides were reported as potent and selective antagonists of such an interaction. Here, we describe the protein crystal structure guided optimization of prototypic compound 2 (K dis = 7 μM), leading to identification of more potent antagonist 47 (K dis = 0.3 μM).

  1. Inhibition of human copper trafficking by a small molecule significantly attenuates cancer cell proliferation. (United States)

    Wang, Jing; Luo, Cheng; Shan, Changliang; You, Qiancheng; Lu, Junyan; Elf, Shannon; Zhou, Yu; Wen, Yi; Vinkenborg, Jan L; Fan, Jun; Kang, Heebum; Lin, Ruiting; Han, Dali; Xie, Yuxin; Karpus, Jason; Chen, Shijie; Ouyang, Shisheng; Luan, Chihao; Zhang, Naixia; Ding, Hong; Merkx, Maarten; Liu, Hong; Chen, Jing; Jiang, Hualiang; He, Chuan


    Copper is a transition metal that plays critical roles in many life processes. Controlling the cellular concentration and trafficking of copper offers a route to disrupt these processes. Here we report small molecules that inhibit the human copper-trafficking proteins Atox1 and CCS, and so provide a selective approach to disrupt cellular copper transport. The knockdown of Atox1 and CCS or their inhibition leads to a significantly reduced proliferation of cancer cells, but not of normal cells, as well as to attenuated tumour growth in mouse models. We show that blocking copper trafficking induces cellular oxidative stress and reduces levels of cellular ATP. The reduced level of ATP results in activation of the AMP-activated protein kinase that leads to reduced lipogenesis. Both effects contribute to the inhibition of cancer cell proliferation. Our results establish copper chaperones as new targets for future developments in anticancer therapies.

  2. Inhibition of human copper trafficking by a small molecule significantly attenuates cancer cell proliferation (United States)

    Wang, Jing; Luo, Cheng; Shan, Changliang; You, Qiancheng; Lu, Junyan; Elf, Shannon; Zhou, Yu; Wen, Yi; Vinkenborg, Jan L.; Fan, Jun; Kang, Heebum; Lin, Ruiting; Han, Dali; Xie, Yuxin; Karpus, Jason; Chen, Shijie; Ouyang, Shisheng; Luan, Chihao; Zhang, Naixia; Ding, Hong; Merkx, Maarten; Liu, Hong; Chen, Jing; Jiang, Hualiang; He, Chuan


    Copper is a transition metal that plays critical roles in many life processes. Controlling the cellular concentration and trafficking of copper offers a route to disrupt these processes. Here we report small molecules that inhibit the human copper-trafficking proteins Atox1 and CCS, and so provide a selective approach to disrupt cellular copper transport. The knockdown of Atox1 and CCS or their inhibition leads to a significantly reduced proliferation of cancer cells, but not of normal cells, as well as to attenuated tumour growth in mouse models. We show that blocking copper trafficking induces cellular oxidative stress and reduces levels of cellular ATP. The reduced level of ATP results in activation of the AMP-activated protein kinase that leads to reduced lipogenesis. Both effects contribute to the inhibition of cancer cell proliferation. Our results establish copper chaperones as new targets for future developments in anticancer therapies.

  3. Identification of MAC1: A Small Molecule That Rescues Spindle Bipolarity in Monastrol-Treated Cells. (United States)

    Al-Obaidi, Naowras; Mitchison, Timothy J; Crews, Craig M; Mayer, Thomas U


    The genetic integrity of each organism is intimately tied to the correct segregation of its genome during mitosis. Insights into the underlying mechanisms are fundamental for both basic research and the development of novel strategies to treat mitosis-relevant diseases such as cancer. Due to their fast mode of action, small molecules are invaluable tools to dissect mitosis. Yet, there is a great demand for novel antimitotic compounds. We performed a chemical genetic suppression screen to identify compounds that restore spindle bipolarity in cells treated with Monastrol, an inhibitor of the mitotic kinesin Eg5. We identified one compound-MAC1-that rescued spindle bipolarity in cells lacking Eg5 activity. Mechanistically, MAC1 induces the formation of additional microtubule nucleation centers, which allows kinesin Kif15-dependent bipolar spindle assembly in the absence of Eg5 activity. Thus, our chemical genetic suppression screen revealed novel unexpected insights into the mechanism of spindle assembly in mammalian cells.

  4. Elasticity Dominated Surface Segregation of Small Molecules in Polymer Mixtures (United States)

    Krawczyk, Jarosław; Croce, Salvatore; McLeish, T. C. B.; Chakrabarti, Buddhapriya


    We study the phenomenon of migration of the small molecular weight component of a binary polymer mixture to the free surface using mean field and self-consistent field theories. By proposing a free energy functional that incorporates polymer-matrix elasticity explicitly, we compute the migrant volume fraction and show that it decreases significantly as the sample rigidity is increased. A wetting transition, observed for high values of the miscibility parameter can be prevented by increasing the matrix rigidity. Estimated values of the bulk modulus suggest that the effect should be observable experimentally for rubberlike materials. This provides a simple way of controlling surface migration in polymer mixtures and can play an important role in industrial formulations, where surface migration often leads to decreased product functionality.

  5. Non-Collinearity in Small Magnetic Cobalt-Benzene Molecules

    CERN Document Server

    González, J W; Delgado, F; Aguilera-Granja, F; Ayuela, A


    Cobalt clusters covered with benzene in the form of rice-ball structures have recently been synthesized using laser ablation. Here, we investigate the types of magnetic order such clusters have, and whether they retain any magnetic order at all. We use different density functional theory (DFT) methods to study the experimentally relevant three cobalt atoms surrounded by benzene rings. We found that the benzene rings induce a ground state with non-collinear magnetization, with the magnetic moments localized on the cobalt centers and lying on the plane formed by the three cobalt atoms. This is surprising because nanostructures and small clusters based on pure cobalt typically have a predominantly ferromagnetic order, and additional organic ligands such as benzene tend to remove the magnetization. We analyze the magnetism of such a cluster using an anisotropic Heisenberg model where the involved parameters are obtained by a comparison with the DFT results. Moreover, we propose electron paramagnetic resonance as ...

  6. Small Molecules from Spiders Used as Chemical Probes

    DEFF Research Database (Denmark)

    Olsen, Christian Adam; Kristensen, Anders S.; Strømgaard, Kristian


    Spiders are important species in ecological systems and as major predators of insects they are endowed with a plethora of low‐molecular‐weight natural products having intriguing biological activities. The isolation and biological characterization of these entities are well established, however, o...

  7. LC-MSMS identification of small molecules; X-Rank, a robust library search algorithm


    Mylonas, Roman


    Identification of small molecules is of major importance for many applications. Liquid Chromatography Tandem Mass spectrometry (LC- MSMS) is gaining increasing interest in the field of small molecule identification. LC-MSMS has a broad range of detection, is sensitive and does not need special sample pre-processing. As a major chal- lenge, spectra of the same compound can show great variability across acquisitions. High spectra variability limits the use of LC-MSMS for library search identifi...

  8. A-D-A small molecules for solution-processed organic photovoltaic cells. (United States)

    Ni, Wang; Wan, Xiangjian; Li, Miaomiao; Wang, Yunchuang; Chen, Yongsheng


    A-D-A small molecules have drawn more and more attention in solution-processed organic solar cells due to the advantages of a diversity of structures, easy control of energy levels, etc. Recently, a power conversion efficiency of nearly 10% has been achieved through careful material design and device optimization. This feature article reviews recent representative progress in the design and application of A-D-A small molecules in organic photovoltaic cells.

  9. Genome-wide characterisation of the binding repertoire of small molecule drugs

    Directory of Open Access Journals (Sweden)

    Makowski Lee


    Full Text Available Abstract Most, if not all, drugs interact with multiple proteins. One or more of these interactions are responsible for carrying out the primary therapeutic effects of the drug. Others are involved in the transport or metabolic processing of the drug or in the mediation of side effects. Still others may be responsible for activities that correspond to alternate therapeutic applications. The potential clinical impact of a drug and its cost of development are affected by the sum of all these interactions. The drug development process includes the identification and characterisation of a drug's clinically relevant interactions. This characterisation is presently accomplished by a combination of experimental laboratory techniques and clinical trials, with increasing numbers of patient participants. Efficient methods for the identification of all the molecular targets of a drug prior to clinical trials could greatly expedite the drug development process. Combinatorial peptide and cDNA phage display have the potential for achieving a complete characterisation of the binding repertoire of a small molecule. This paper will discuss the current state of phage display technology, as applied to the identification of novel receptors for small molecules, using a successful application with the drug Taxol™ as an example of the technical and theoretical benefits and pitfalls of this method.

  10. Chemoselective small molecules that covalently modify one lysine in a non-enzyme protein in plasma

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Sungwook; Connelly, Stephen; Reixach, Natàlia; Wilson, Ian A.; Kelly, Jeffery W. (Scripps)


    A small molecule that could bind selectively to and then react chemoselectively with a non-enzyme protein in a complex biological fluid, such as blood, could have numerous practical applications. Herein, we report a family of designed stilbenes that selectively and covalently modify the prominent plasma protein transthyretin in preference to more than 4,000 other human plasma proteins. They react chemoselectively with only one of eight lysine {epsilon}-amino groups within transthyretin. The crystal structure confirms the expected binding orientation of the stilbene substructure and the anticipated conjugating amide bond. These covalent transthyretin kinetic stabilizers exhibit superior amyloid inhibition potency compared to their noncovalent counterparts, and they prevent cytotoxicity associated with amyloidogenesis. Though there are a few prodrugs that, upon metabolic activation, react with a cysteine residue inactivating a specific non-enzyme, we are unaware of designed small molecules that react with one lysine {epsilon}-amine within a specific non-enzyme protein in a complex biological fluid.

  11. Identification and characterization of potent small molecule inhibitor of hemorrhagic fever New World arenaviruses. (United States)

    Bolken, Tove C; Laquerre, Sylvie; Zhang, Yuanming; Bailey, Thomas R; Pevear, Daniel C; Kickner, Shirley S; Sperzel, Lindsey E; Jones, Kevin F; Warren, Travis K; Amanda Lund, S; Kirkwood-Watts, Dana L; King, David S; Shurtleff, Amy C; Guttieri, Mary C; Deng, Yijun; Bleam, Maureen; Hruby, Dennis E


    Category A arenaviruses as defined by the National Institute of Allergy and Infectious Diseases (NIAID) are human pathogens that could be weaponized by bioterrorists. Many of these deadly viruses require biosafety level-4 (BSL-4) containment for all laboratory work, which limits traditional laboratory high-throughput screening (HTS) for identification of small molecule inhibitors. For those reasons, a related BSL-2 New World arenavirus, Tacaribe virus, 67-78% identical to Junín virus at the amino acid level, was used in a HTS campaign where approximately 400,000 small molecule compounds were screened in a Tacaribe virus-induced cytopathic effect (CPE) assay. Compounds identified in this screen showed antiviral activity and specificity against not only Tacaribe virus, but also the Category A New World arenaviruses (Junín, Machupo, and Guanarito). Drug resistant variants were isolated, suggesting that these compounds act through inhibition of a viral protein, the viral glycoprotein (GP2), and not through cellular toxicity mechanisms. A lead compound, ST-294, has been chosen for drug development. This potent and selective compound, with good bioavailability, demonstrated protective anti-viral efficacy in a Tacaribe mouse challenge model. This series of compounds represent a new class of inhibitors that may warrant further development for potential inclusion in a strategic stockpile.

  12. Silver nanoislands on cellulose fibers for chromatographic separation and ultrasensitive detection of small molecules

    Institute of Scientific and Technical Information of China (English)

    Hyukjin Jung; Moonseong Park; Minhee Kang; Ki-Hun Jeong


    High-throughput small-molecule assays play essential roles in biomedical diagnosis,drug discovery,environmental analysis,and physiological function research.Nanoplasmonics holds a great potential for the label-free detection of small molecules at extremely low concentrations.Here,we report the development of nanoplasmonic paper (NP-paper) for the rapid separation and ultrasensitive detection of mixed small molecules.NP-paper employs nanogap-rich silver nanoislands on cellulose fibers,which were simply fabricated at the wafer level by using low-temperature solid-state dewetting of a thin silver film.The nanoplasmonic detection allows for the scalable quantification and identification of small molecules over broad concentration ranges.Moreover,the combination of chromatographic separation and nanoplasmonic detection allows both the highly sensitive fluorescence detection of mixed small molecules at the attogram level and the label-free detection at the sub-nanogram level based on surface-enhanced Raman scattering.This novel material provides a new diagnostic platform for the high-throughput,low-cost,and label-free screening of mixed small molecules as an alternative to conventional paper chromatography.

  13. X-ray crystallography: Assessment and validation of protein-small molecule complexes for drug discovery (United States)

    Cooper, David R.; Porebski, Przemyslaw J.; Chruszcz, Maksymilian; Minor, Wladek


    Introduction Crystallography is the key initial component for structure-based and fragment-based drug design and can often generate leads that can be developed into high potency drugs. Therefore, huge sums of money are committed based on the outcome of crystallography experiments and their interpretation. Areas covered This review discusses how to evaluate the correctness of an X-ray structure, focusing on the validation of small molecule-protein complexes. Various types of inaccuracies found within the PDB are identified and the ramifications of these errors are discussed. The reader will gain an understanding of the key parameters that need to be inspected before a structure can be used in drug discovery efforts, as well as an appreciation of the difficulties of correctly interpreting electron density for small molecules. The reader will also be introduced to methods for validating small molecules within the context of a macromolecular structure. Expert opinion One of the reasons that ligand identification and positioning, within a macromolecular crystal structure, is so difficult is that the quality of small molecules widely varies in the PDB. For this reason, the PDB can not always be considered a reliable repository of structural information pertaining to small molecules, and this makes the derivation of general principles that govern small molecule-protein interactions more difficult. PMID:21779303

  14. Identification of Novel Small Molecule Inhibitors of Oncogenic RET Kinase.

    Directory of Open Access Journals (Sweden)

    Marialuisa Moccia

    Full Text Available Oncogenic mutation of the RET receptor tyrosine kinase is observed in several human malignancies. Here, we describe three novel type II RET tyrosine kinase inhibitors (TKI, ALW-II-41-27, XMD15-44 and HG-6-63-01, that inhibit the cellular activity of oncogenic RET mutants at two digit nanomolar concentration. These three compounds shared a 3-trifluoromethyl-4-methylpiperazinephenyl pharmacophore that stabilizes the 'DFG-out' inactive conformation of RET activation loop. They blocked RET-mediated signaling and proliferation with an IC50 in the nM range in fibroblasts transformed by the RET/C634R and RET/M918T oncogenes. They also inhibited autophosphorylation of several additional oncogenic RET-derived point mutants and chimeric oncogenes. At a concentration of 10 nM, ALW-II-41-27, XMD15-44 and HG-6-63-01 inhibited RET kinase and signaling in human thyroid cancer cell lines carrying oncogenic RET alleles; they also inhibited proliferation of cancer, but not non-tumoral Nthy-ori-3-1, thyroid cells, with an IC50 in the nM range. The three compounds were capable of inhibiting the 'gatekeeper' V804M mutant which confers substantial resistance to established RET inhibitors. In conclusion, we have identified a type II TKI scaffold, shared by ALW-II-41-27, XMD15-44 and HG-6-63-01, that may be used as novel lead for the development of novel agents for the treatment of cancers harboring oncogenic activation of RET.

  15. Identification of Novel Small Molecule Inhibitors of Oncogenic RET Kinase. (United States)

    Moccia, Marialuisa; Liu, Qingsong; Guida, Teresa; Federico, Giorgia; Brescia, Annalisa; Zhao, Zheng; Choi, Hwan Geun; Deng, Xianming; Tan, Li; Wang, Jinhua; Billaud, Marc; Gray, Nathanael S; Carlomagno, Francesca; Santoro, Massimo


    Oncogenic mutation of the RET receptor tyrosine kinase is observed in several human malignancies. Here, we describe three novel type II RET tyrosine kinase inhibitors (TKI), ALW-II-41-27, XMD15-44 and HG-6-63-01, that inhibit the cellular activity of oncogenic RET mutants at two digit nanomolar concentration. These three compounds shared a 3-trifluoromethyl-4-methylpiperazinephenyl pharmacophore that stabilizes the 'DFG-out' inactive conformation of RET activation loop. They blocked RET-mediated signaling and proliferation with an IC50 in the nM range in fibroblasts transformed by the RET/C634R and RET/M918T oncogenes. They also inhibited autophosphorylation of several additional oncogenic RET-derived point mutants and chimeric oncogenes. At a concentration of 10 nM, ALW-II-41-27, XMD15-44 and HG-6-63-01 inhibited RET kinase and signaling in human thyroid cancer cell lines carrying oncogenic RET alleles; they also inhibited proliferation of cancer, but not non-tumoral Nthy-ori-3-1, thyroid cells, with an IC50 in the nM range. The three compounds were capable of inhibiting the 'gatekeeper' V804M mutant which confers substantial resistance to established RET inhibitors. In conclusion, we have identified a type II TKI scaffold, shared by ALW-II-41-27, XMD15-44 and HG-6-63-01, that may be used as novel lead for the development of novel agents for the treatment of cancers harboring oncogenic activation of RET.


    Institute of Scientific and Technical Information of China (English)

    Chi-fei Wu; Saburo Akiyama


    The addition effects of organic small molecular substances N,N'-dicyclohexyl-benzothiazyl-2-sulfenamide (DZ) and 3,9-bis{ 1, 1-dimethyl-2[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8, 10-tetraoxaspiro[5,5]-undecane (AO-80) on the dynamic mechanical properties of chlorinated polyethylene (CPE), chlorinated polypropylene (CPP), acrylate rubber (ACM) and their blends were investigated. In the case of compatible systems such as CPE/DZ and ACM/AO-80, the height of the loss tangent (tanδ) peak of a matrix polymer (CPE or ACM) increases, and its peak position shifts to a higher temperature with the addition of DZ or AO-80. By contrast, for incompatible CPE/AO-80, a novel transition appeared above the glass transition temperature of CPE. This additional transition was assigned to dissociation of the intermolecular hydrogen bond between the α-hydrogen of CPE and the hydroxyl groups of AO-80 within the AO-80-rich domain. This will provide a new concept for developing damping material. However, the minimum value between two tanδ peaks is lower. It was found that the temperature dependence of tanδ could be improved by adding chlorinated paraffin (CP) or ACM to CPE/AO-80. In addition, another ternary system of ACM/CPP with more AO-80 was found to be a very good self-adhesive damping material because of the appearance of a novel transition due to an interfacial layer of ACM/CPP.

  17. A novel small molecule inhibitor targeted at Bcl-2

    Institute of Scientific and Technical Information of China (English)

    JIN; LiJi; ZHANG; ZhiChao; WANG; YuanYuan; WEI; MeiJiao; XU; Qin


    Recently, the heterocyclic compound 8-oxo-3-thiomorpholino-8H-acenaphtho[1,2-b]pyrrole-9-carbonitrile (S1) was synthesized and shown to induce apoptosis in both (H22) hematoma and (MCF-7) adenocarcinoma cells. The IC50 values of S1 against the two cell lines were 0.17 and 0.09 μmol/L, respectively. Furthermore, the apoptosis-inducing activity of this compound was highlighted both in vivo and in vitro. Subsequent experiments identified Bcl-2 as the primary target of S1, as a significant reduction in Bcl-2 protein levels was observed in H22 cells following a two-hour treatment with 10 μmol/L S1. While rapid depolarization of mitochondrial membranes led immediately to caspase 9 activation, no changes were identified in either caspase 8 levels or levels in Bcl-2 mRNA. These data were consistent with the results of circular dichroism (CD) spectra analysis, revealing that S1 inactivated the Bcl-2 protein by destroying its critical alpha helices. Taken together, these results suggest the potential of S1 in the development of new therapeutic agents.

  18. Structure-based drug design of small molecule SIRT1 modulators to treat cancer and metabolic disorders. (United States)

    Pulla, Venkat Koushik; Alvala, Mallika; Sriram, Dinavahi Saketh; Viswanadha, Srikant; Sriram, Dharmarajan; Yogeeswari, Perumal


    Sirtuins comprise a family of deacetylase enzymes that catalyze the removal of an acetyl moiety from the ɛ-amino group of lysine residues within protein targets. Sirtuin 1(SIRT1), a NAD(+) dependent class III histone deacetylase is involved in a variety of human disorders such as obesity, type II diabetes, cancer and aging. Inhibition of SIRT1 could be useful for cancer treatment while activators can be useful for longevity and treating metabolic disorders. Hence we undertook an effort to design both inhibitors and activators using structure-based drug design techniques and report here the biological proof of concept. In this paper, we report diverse small molecule inhibitors with a potential to attenuate cancer growth designed based on high-throughput virtual screening and docking using the crystal structure of SIRT1. And small molecule activators with potential to suppress adipogenesis differentiation indicating their usefulness in obesity control was designed based on a homology model of SIRT1 activator domain.

  19. Combinatorics of feedback in cellular uptake and metabolism of small molecules. (United States)

    Krishna, Sandeep; Semsey, Szabolcs; Sneppen, Kim


    We analyze the connection between structure and function for regulatory motifs associated with cellular uptake and usage of small molecules. Based on the boolean logic of the feedback we suggest four classes: the socialist, consumer, fashion, and collector motifs. We find that the socialist motif is good for homeostasis of a useful but potentially poisonous molecule, whereas the consumer motif is optimal for nutrition molecules. Accordingly, examples of these motifs are found in, respectively, the iron homeostasis system in various organisms and in the uptake of sugar molecules in bacteria. The remaining two motifs have no obvious analogs in small molecule regulation, but we illustrate their behavior using analogies to fashion and obesity. These extreme motifs could inspire construction of synthetic systems that exhibit bistable, history-dependent states, and homeostasis of flux (rather than concentration).

  20. Discovery of an inhibitor of a transcription factor using small molecule microarrays and diversity-oriented synthesis. (United States)

    Koehler, Angela N; Shamji, Alykhan F; Schreiber, Stuart L


    Small molecule microarrays were screened to identify a small molecule ligand for Hap3p, a subunit of the yeast Hap2/3/4/5p transcription factor complex. The compound, named haptamide A, was determined to have a KD of 5.03 muM for binding to Hap3p using surface plasmon resonance analysis. Haptamide A also inhibited activation of a GDH1-lacZ reporter gene in a dose-dependent fashion. To explore structure-activity relationships, 11 derivatives of haptamide A were prepared using the same synthetic route that was developed for the original library synthesis. Analysis of dissociation constants and IC50 values for the reporter gene assay revealed a more potent inhibitor, haptamide B, with a KD of 330 nM. Whole-genome transcriptional profiling was used to compare effects of haptamide B with a hap3Delta yeast strain. Treatment with haptamide B, like the deletion mutant, reduced lactate-induced transcription of several genes from wild-type levels. Profiling the genetic "knockout" and the chemical genetic "knockdown" led to the identification of several genes that are regulated by Hap3p under nonfermentative conditions. These results demonstrate that a small molecule discovered using the small molecule microarray binding assay can permeate yeast cells and reach its target transcription factor protein in cells.

  1. Small Molecule-Induced Domain Swapping as a Mechanism for Controlling Protein Function and Assembly (United States)

    Karchin, Joshua M.; Ha, Jeung-Hoi; Namitz, Kevin E.; Cosgrove, Michael S.; Loh, Stewart N.


    Domain swapping is the process by which identical proteins exchange reciprocal segments to generate dimers. Here we introduce induced domain swapping (INDOS) as a mechanism for regulating protein function. INDOS employs a modular design consisting of the fusion of two proteins: a recognition protein that binds a triggering molecule, and a target protein that undergoes a domain swap in response to binding of the triggering ligand. The recognition protein (FK506 binding protein) is inserted into functionally-inactivated point mutants of two target proteins (staphylococcal nuclease and ribose binding protein). Binding of FK506 to the FKBP domain causes the target domain to first unfold, then refold via domain swap. The inactivating mutations become ‘swapped out’ in the dimer, increasing nuclease and ribose binding activities by 100-fold and 15-fold, respectively, restoring them to near wild-type values. INDOS is intended to convert an arbitrary protein into a functional switch, and is the first example of rational design in which a small molecule is used to trigger protein domain swapping and subsequent activation of biological function. PMID:28287617

  2. Prediction of small molecule binding property of protein domains with Bayesian classifiers based on Markov chains. (United States)

    Bulashevska, Alla; Stein, Martin; Jackson, David; Eils, Roland


    Accurate computational methods that can help to predict biological function of a protein from its sequence are of great interest to research biologists and pharmaceutical companies. One approach to assume the function of proteins is to predict the interactions between proteins and other molecules. In this work, we propose a machine learning method that uses a primary sequence of a domain to predict its propensity for interaction with small molecules. By curating the Pfam database with respect to the small molecule binding ability of its component domains, we have constructed a dataset of small molecule binding and non-binding domains. This dataset was then used as training set to learn a Bayesian classifier, which should distinguish members of each class. The domain sequences of both classes are modelled with Markov chains. In a Jack-knife test, our classification procedure achieved the predictive accuracies of 77.2% and 66.7% for binding and non-binding classes respectively. We demonstrate the applicability of our classifier by using it to identify previously unknown small molecule binding domains. Our predictions are available as supplementary material and can provide very useful information to drug discovery specialists. Given the ubiquitous and essential role small molecules play in biological processes, our method is important for identifying pharmaceutically relevant components of complete proteomes. The software is available from the author upon request.

  3. Small-molecule antioxidant proteome-shields in Deinococcus radiodurans.

    Directory of Open Access Journals (Sweden)

    Michael J Daly

    Full Text Available For Deinococcus radiodurans and other bacteria which are extremely resistant to ionizing radiation, ultraviolet radiation, and desiccation, a mechanistic link exists between resistance, manganese accumulation, and protein protection. We show that ultrafiltered, protein-free preparations of D. radiodurans cell extracts prevent protein oxidation at massive doses of ionizing radiation. In contrast, ultrafiltrates from ionizing radiation-sensitive bacteria were not protective. The D. radiodurans ultrafiltrate was enriched in Mn, phosphate, nucleosides and bases, and peptides. When reconstituted in vitro at concentrations approximating those in the D. radiodurans cytosol, peptides interacted synergistically with Mn(2+ and orthophosphate, and preserved the activity of large, multimeric enzymes exposed to 50,000 Gy, conditions which obliterated DNA. When applied ex vivo, the D. radiodurans ultrafiltrate protected Escherichia coli cells and human Jurkat T cells from extreme cellular insults caused by ionizing radiation. By establishing that Mn(2+-metabolite complexes of D. radiodurans specifically protect proteins against indirect damage caused by gamma-rays delivered in vast doses, our findings provide the basis for a new approach to radioprotection and insight into how surplus Mn budgets in cells combat reactive oxygen species.

  4. Stimulators of translation identified during a small molecule screening campaign. (United States)

    Shin, Unkyung; Williams, David E; Kozakov, Dima; Hall, David R; Beglov, Dmitri; Vajda, Sandor; Andersen, Raymond J; Pelletier, Jerry


    In screening a library of natural and synthetic products for eukaryotic translation modulators, we identified two natural products, isohymenialdisine and hymenialdisine, that exhibit stimulatory effects on translation. The characterization of these compounds led to the insight that mRNA used to program the translation extracts during high-throughput assay setup was leading to phosphorylation of eIF2α, a potent negative regulatory event that is mediated by one of four kinases. We identified double-stranded RNA-dependent protein kinase (PKR) as the eIF2α kinase that was being activated by exogenously added mRNA template. Characterization of the mode of action of isohymenialdisine revealed that it directly acts on PKR by inhibiting autophosphorylation, perturbs the PKR-eIF2α phosphorylation axis, and can be modeled into the PKR ATP binding site. Our results identify a source of "false positives" for high-throughput screen campaigns using translation extracts, raising a cautionary note for this type of screen.

  5. Self-organizing ontology of biochemically relevant small molecules

    Directory of Open Access Journals (Sweden)

    Chepelev Leonid L


    Full Text Available Abstract Background The advent of high-throughput experimentation in biochemistry has led to the generation of vast amounts of chemical data, necessitating the development of novel analysis, characterization, and cataloguing techniques and tools. Recently, a movement to publically release such data has advanced biochemical structure-activity relationship research, while providing new challenges, the biggest being the curation, annotation, and classification of this information to facilitate useful biochemical pattern analysis. Unfortunately, the human resources currently employed by the organizations supporting these efforts (e.g. ChEBI are expanding linearly, while new useful scientific information is being released in a seemingly exponential fashion. Compounding this, currently existing chemical classification and annotation systems are not amenable to automated classification, formal and transparent chemical class definition axiomatization, facile class redefinition, or novel class integration, thus further limiting chemical ontology growth by necessitating human involvement in curation. Clearly, there is a need for the automation of this process, especially for novel chemical entities of biological interest. Results To address this, we present a formal framework based on Semantic Web technologies for the automatic design of chemical ontology which can be used for automated classification of novel entities. We demonstrate the automatic self-assembly of a structure-based chemical ontology based on 60 MeSH and 40 ChEBI chemical classes. This ontology is then used to classify 200 compounds with an accuracy of 92.7%. We extend these structure-based classes with molecular feature information and demonstrate the utility of our framework for classification of functionally relevant chemicals. Finally, we discuss an iterative approach that we envision for future biochemical ontology development. Conclusions We conclude that the proposed methodology

  6. Small molecule control of virulence gene expression in Francisella tularensis.

    Directory of Open Access Journals (Sweden)

    James C Charity


    Full Text Available In Francisella tularensis, the SspA protein family members MglA and SspA form a complex that associates with RNA polymerase (RNAP to positively control the expression of virulence genes critical for the intramacrophage growth and survival of the organism. Although the association of the MglA-SspA complex with RNAP is evidently central to its role in controlling gene expression, the molecular details of how MglA and SspA exert their effects are not known. Here we show that in the live vaccine strain of F. tularensis (LVS, the MglA-SspA complex works in concert with a putative DNA-binding protein we have called PigR, together with the alarmone guanosine tetraphosphate (ppGpp, to regulate the expression of target genes. In particular, we present evidence that MglA, SspA, PigR and ppGpp regulate expression of the same set of genes, and show that mglA, sspA, pigR and ppGpp null mutants exhibit similar intramacrophage growth defects and are strongly attenuated for virulence in mice. We show further that PigR interacts directly with the MglA-SspA complex, suggesting that the central role of the MglA and SspA proteins in the control of virulence gene expression is to serve as a target for a transcription activator. Finally, we present evidence that ppGpp exerts its effects by promoting the interaction between PigR and the RNAP-associated MglA-SspA complex. Through its responsiveness to ppGpp, the contact between PigR and the MglA-SspA complex allows the integration of nutritional cues into the regulatory network governing virulence gene expression.

  7. Calcium phosphate nanoparticles as versatile carrier for small and large molecules across cell membranes

    Energy Technology Data Exchange (ETDEWEB)

    Sokolova, Viktoriya; Rotan, Olga; Klesing, Jan [University of Duisburg-Essen, Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany); Nalbant, Perihan [University of Duisburg-Essen, Faculty of Biology, Institute of Molecular Cell Biology (Germany); Buer, Jan; Knuschke, Torben; Westendorf, Astrid M. [University Hospital Essen, University of Duisburg-Essen, Institute of Medical Microbiology (Germany); Epple, Matthias, E-mail: [University of Duisburg-Essen, Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE) (Germany)


    The successful transport of molecules across the cell membrane is a key point in biology and medicine. In most cases, molecules alone cannot penetrate the cell membrane, therefore an efficient carrier is needed. Calcium phosphate nanoparticles (diameter: 100-250 nm, depending on the functionalization) were loaded with fluorescent oligonucleotides, peptide, proteins, antibodies, polymers or porphyrins and characterized by dynamic light scattering, nanoparticle tracking analysis and scanning electron microscopy. Any excess of molecules was removed by ultracentrifugation, and the dissolved molecules at the same concentration were used as control. The uptake of such fluorescence-labeled nanoparticles into HeLa cells was monitored by fluorescence microscopy and confocal laser scanning microscopy. Calcium phosphate nanoparticles were able to transport all molecules across the cell membrane, whereas the dissolved molecules alone were taken up only to a very small extent or even not at all.

  8. Tetrakis(dimethoxyphenyl)adamantane (TDA) and its inclusion complexes in the crystalline state: a versatile carrier for small molecules. (United States)

    Schwenger, Alexander; Frey, Wolfgang; Richert, Clemens


    Molecular storage solutions for incorporating small molecules in crystalline matrices are of interest in the context of structure elucidation, decontamination, and slow release of active ingredients. Here we report the syntheses of 1,3,5,7-tetrakis(2,4-dimethoxyphenyl)adamantane, 1,3,5,7-tetrakis(4-methoxyphenyl)adamantane, 1,3,5,7-tetrakis(4-methoxy-2-methylphenyl)adamantane, and 1,3,5,7-tetrakis(4-methoxy-2-ethylphenyl)adamantane, together with their X-ray crystal structures. All four compounds crystallize readily. Only the octaether shows an unusual level of (pseudo)polymorphism in its crystalline state, combined with the ability to include a number of different small molecules in its crystal lattices. A total of 20 different inclusion complexes with guest molecules as different as ethanol or trifluorobenzene were found. For nitromethane and benzene, schemes for uptake and release are presented.

  9. Discovery and computer aided potency optimization of a novel class of small molecule CXCR4 antagonists.

    Directory of Open Access Journals (Sweden)

    Victoria Vinader

    Full Text Available Amongst the chemokine signalling axes involved in cancer, chemokine CXCL12 acting on chemokine receptor CXCR4 is particularly significant since it orchestrates migration of cancer cells in a tissue-specific metastatic process. High CXCR4 tumour expression is associated with poor prognosis of lung, brain, CNS, blood and breast cancers. We have identified a new class of small molecule CXCR4 antagonists based on the use of computational modelling studies in concert with experimental determination of in vitro activity against CXCL12-induced intracellular calcium mobilisation, proliferation and chemotaxis. Molecular modelling proved to be a useful tool in rationalising our observed potencies, as well as informing the direction of the synthetic efforts aimed at producing more potent compounds.

  10. Identification of potential small molecule allosteric modulator sites on IL-1R1 ectodomain using accelerated conformational sampling method.

    Directory of Open Access Journals (Sweden)

    Chao-Yie Yang

    Full Text Available The interleukin-1 receptor (IL-1R is the founding member of the interleukin 1 receptor family which activates innate immune response by its binding to cytokines. Reports showed dysregulation of cytokine production leads to aberrant immune cells activation which contributes to auto-inflammatory disorders and diseases. Current therapeutic strategies focus on utilizing antibodies or chimeric cytokine biologics. The large protein-protein interaction interface between cytokine receptor and cytokine poses a challenge in identifying binding sites for small molecule inhibitor development. Based on the significant conformational change of IL-1R type 1 (IL-1R1 ectodomain upon binding to different ligands observed in crystal structures, we hypothesized that transient small molecule binding sites may exist when IL-1R1 undergoes conformational transition and thus suitable for inhibitor development. Here, we employed accelerated molecular dynamics (MD simulation to efficiently sample conformational space of IL-1R1 ectodomain. Representative IL-1R1 ectodomain conformations determined from the hierarchy cluster analysis were analyzed by the SiteMap program which leads to identify small molecule binding sites at the protein-protein interaction interface and allosteric modulator locations. The cosolvent mapping analysis using phenol as the probe molecule further confirms the allosteric modulator site as a binding hotspot. Eight highest ranked fragment molecules identified from in silico screening at the modulator site were evaluated by MD simulations. Four of them restricted the IL-1R1 dynamical motion to inactive conformational space. The strategy from this study, subject to in vitro experimental validation, can be useful to identify small molecule compounds targeting the allosteric modulator sites of IL-1R and prevent IL-1R from binding to cytokine by trapping IL-1R in inactive conformations.

  11. A modular molecular framework for utility in small-molecule solution-processed organic photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Welch, Gregory C. [Univ. of California, Santa Barbara, CA (United States). Center for Energy Efficient Materials; Perez, Louis A. [Univ. of California, Santa Barbara, CA (United States). Center for Energy Efficient Materials and Dept. of Materials; Hoven, Corey V. [Univ. of California, Santa Barbara, CA (United States). Center for Energy Efficient Materials; Zhang, Yuan [Univ. of California, Santa Barbara, CA (United States). Center for Energy Efficient Materials; Dang, Xuan-Dung [Univ. of California, Santa Barbara, CA (United States). Center for Energy Efficient Materials; Sharenko, Alexander [Univ. of California, Santa Barbara, CA (United States). Center for Energy Efficient Materials and Dept. of Materials; Toney, Michael F. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL); Kramer, Edward J. [Univ. of California, Santa Barbara, CA (United States). Dept. of Chemical Engineering and Dept. of Materials; Nguyen, Thuc-Quyen [Univ. of California, Santa Barbara, CA (United States). Center for Energy Efficient Materials, Center for Polymers and Organic Solids and Dept. of Chemistry & Biochemistry; Bazan, Guillermo C. [Univ. of California, Santa Barbara, CA (United States). Center for Energy Efficient Materials, Center for Polymers and Organic Solids, Dept. of Chemistry & Biochemistry and Dept. of Materials


    We report on the design, synthesis and characterization of light harvesting small molecules for use in solution-processed small molecule bulk heterojunction (SM-BHJ) solar cell devices. These molecular materials are based upon an acceptor/donor/acceptor (A/D/A) core with donor endcapping units. Utilization of a dithieno(3,2-b;2',3'-d)silole (DTS) donor and pyridal[2,1,3]thiadiazole (PT) acceptor leads to strong charge transfer characteristics, resulting in broad optical absorption spectra extending well beyond 700 nm. SM-BHJ solar cell devices fabricated with the specific example 5,5'-bis{7-(4-(5-hexylthiophen-2-yl)thiophen-2-yl)-[1,2,5]thiadiazolo[3,4-c]pyridine}-3,3'-di-2-ethylhexylsilylene-2,2'-bithiophene (6) as the donor and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor component showed short circuit currents above -10 mA cm-2 and power conversion efficiencies (PCEs) over 3%. Thermal processing is a critical factor in obtaining favorable active layer morphologies and high PCE values. A combination of UV-visible spectroscopy, conductive and photo-conductive atomic force microscopies, dynamic secondary mass ion spectrometry (DSIMS), and grazing incident wide angle X-ray scattering (GIWAXS) experiments were carried out to characterize how thermal treatment influences the active layer structure and organization.

  12. A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

    Directory of Open Access Journals (Sweden)

    Stefanie Wolfram


    Full Text Available Molecular probes are widely used tools in chemical biology that allow tracing of bioactive metabolites and selective labeling of proteins and other biomacromolecules. A common structural motif for such probes consists of a reporter that can be attached by copper(I-catalyzed 1,2,3-triazole formation between terminal alkynes and azides to a reactive headgroup. Here we introduce the synthesis and application of the new thiazole-based, azide-tagged reporter 4-(3-azidopropoxy-5-(4-bromophenyl-2-(pyridin-2-ylthiazole for fluorescence, UV and mass spectrometry (MS detection. This small fluorescent reporter bears a bromine functionalization facilitating the automated data mining of electrospray ionization MS runs by monitoring for its characteristic isotope signature. We demonstrate the universal utility of the reporter for the detection of an alkyne-modified small molecule by LC–MS and for the visualization of a model protein by in-gel fluorescence. The novel probe advantageously compares with commercially available azide-modified fluorophores and a brominated one. The ease of synthesis, small size, stability, and the universal detection possibilities make it an ideal reporter for activity-based protein profiling and functional metabolic profiling.

  13. Mechanistic understanding and significance of small peptides interaction with MHC class II molecules for therapeutic applications. (United States)

    Afridi, Saifullah; Hoessli, Daniel C; Hameed, Muhammad Waqar


    Major histocompatibility complex (MHC) class II molecules are expressed by antigen-presenting cells and stimulate CD4(+) T cells, which initiate humoral immune responses. Over the past decade, interest has developed to therapeutically impact the peptides to be exposed to CD4(+) T cells. Structurally diverse small molecules have been discovered that act on the endogenous peptide exchanger HLA-DM by different mechanisms. Exogenously delivered peptides are highly susceptible to proteolytic cleavage in vivo; however, it is only when successfully incorporated into stable MHC II-peptide complexes that these peptides can induce an immune response. Many of the small molecules so far discovered have highlighted the molecular interactions mediating the formation of MHC II-peptide complexes. As potential drugs, these small molecules open new therapeutic approaches to modulate MHC II antigen presentation pathways and influence the quality and specificity of immune responses. This review briefly introduces how CD4(+) T cells recognize antigen when displayed by MHC class II molecules, as well as MHC class II-peptide-loading pathways, structural basis of peptide binding and stabilization of the peptide-MHC complexes. We discuss the concept of MHC-loading enhancers, how they could modulate immune responses and how these molecules have been identified. Finally, we suggest mechanisms whereby MHC-loading enhancers could act upon MHC class II molecules.

  14. Small Molecule DFPM Derivative-Activated Plant Resistance Protein Signaling in Roots Is Unaffected by EDS1 Subcellular Targeting Signal and Chemical Genetic Isolation of victr R-Protein Mutants.

    Directory of Open Access Journals (Sweden)

    Hans-Henning Kunz

    Full Text Available The small molecule DFPM ([5-(3,4-dichlorophenylfuran-2-yl]-piperidine-1-ylmethanethione was recently shown to trigger signal transduction via early effector-triggered immunity signaling genes including EDS1 and PAD4 in Arabidopsis thaliana accession Col-0. Chemical genetic analyses of A. thaliana natural variants identified the plant Resistance protein-like Toll/Interleukin1 Receptor (TIR-Nucleotide Binding (NB-Leucine-Rich Repeat (LRR protein VICTR as required for DFPM-mediated root growth arrest. Here a chemical genetic screen for mutants which disrupt DFPM-mediated root growth arrest in the Col-0 accession identified new mutant alleles of the TIR-NB-LRR gene VICTR. One allele, victr-6, carries a Gly216-to-Asp mutation in the Walker A domain supporting an important function of the VICTR nucleotide binding domain in DFPM responses consistent with VICTR acting as a canonical Resistance protein. The essential nucleo-cytoplasmic regulator of TIR-NB-LRR-mediated effector-triggered immunity, EDS1, was reported to have both nuclear and cytoplasmic actions in pathogen resistance. DFPM was used to investigate the requirements for subcellular EDS1 localization in DFPM-mediated root growth arrest. EDS1-YFP fusions engineered to localize mainly in the cytoplasm or the nucleus by tagging with a nuclear export signal (NES or a nuclear localization signal (NLS, respectively, were tested. We found that wild-type EDS1-YFP and both the NES and NLS-tagged EDS1 variants were induced by DFPM treatments and fully complemented eds1 mutant plants in root responses to DFPM, suggesting that enrichment of EDS1 in either compartment could confer DFPM-mediated root growth arrest. We further found that a light and O2-dependent modification of DFPM is necessary to mediate DFPM signaling in roots. Chemical analyses including Liquid Chromatography-Mass Spectrometry and High-Resolution Atmospheric Pressure Chemical Ionization Mass Spectrometry identified a DFPM modification

  15. Small Molecule DFPM Derivative-Activated Plant Resistance Protein Signaling in Roots Is Unaffected by EDS1 Subcellular Targeting Signal and Chemical Genetic Isolation of victr R-Protein Mutants. (United States)

    Kunz, Hans-Henning; Park, Jiyoung; Mevers, Emily; García, Ana V; Highhouse, Samantha; Gerwick, William H; Parker, Jane E; Schroeder, Julian I


    The small molecule DFPM ([5-(3,4-dichlorophenyl)furan-2-yl]-piperidine-1-ylmethanethione) was recently shown to trigger signal transduction via early effector-triggered immunity signaling genes including EDS1 and PAD4 in Arabidopsis thaliana accession Col-0. Chemical genetic analyses of A. thaliana natural variants identified the plant Resistance protein-like Toll/Interleukin1 Receptor (TIR)-Nucleotide Binding (NB)-Leucine-Rich Repeat (LRR) protein VICTR as required for DFPM-mediated root growth arrest. Here a chemical genetic screen for mutants which disrupt DFPM-mediated root growth arrest in the Col-0 accession identified new mutant alleles of the TIR-NB-LRR gene VICTR. One allele, victr-6, carries a Gly216-to-Asp mutation in the Walker A domain supporting an important function of the VICTR nucleotide binding domain in DFPM responses consistent with VICTR acting as a canonical Resistance protein. The essential nucleo-cytoplasmic regulator of TIR-NB-LRR-mediated effector-triggered immunity, EDS1, was reported to have both nuclear and cytoplasmic actions in pathogen resistance. DFPM was used to investigate the requirements for subcellular EDS1 localization in DFPM-mediated root growth arrest. EDS1-YFP fusions engineered to localize mainly in the cytoplasm or the nucleus by tagging with a nuclear export signal (NES) or a nuclear localization signal (NLS), respectively, were tested. We found that wild-type EDS1-YFP and both the NES and NLS-tagged EDS1 variants were induced by DFPM treatments and fully complemented eds1 mutant plants in root responses to DFPM, suggesting that enrichment of EDS1 in either compartment could confer DFPM-mediated root growth arrest. We further found that a light and O2-dependent modification of DFPM is necessary to mediate DFPM signaling in roots. Chemical analyses including Liquid Chromatography-Mass Spectrometry and High-Resolution Atmospheric Pressure Chemical Ionization Mass Spectrometry identified a DFPM modification product that is

  16. A Small Insulinomimetic Molecule Also Improves Insulin Sensitivity in Diabetic Mice (United States)

    Mukherjee, Sandip; Chattopadhyay, Mrittika; Bhattacharya, Sushmita; Dasgupta, Suman; Hussain, Sahid; Bharadwaj, Saitanya K.; Talukdar, Dhrubajyoti; Usmani, Abul; Pradhan, Bhola S; Majumdar, Subeer S; Chattopadhyay, Pronobesh; Mukhopadhyay, Satinath; Maity, Tushar K; Chaudhuri, Mihir K.; Bhattacharya, Samir


    Dramatic increase of diabetes over the globe is in tandem with the increase in insulin requirement. This is because destruction and dysfunction of pancreatic β-cells are of common occurrence in both Type1 diabetes and Type2 diabetes, and insulin injection becomes a compulsion. Because of several problems associated with insulin injection, orally active insulin mimetic compounds would be ideal substitute. Here we report a small molecule, a peroxyvanadate compound i.e. DmpzH[VO(O2)2(dmpz)], henceforth referred as dmp, which specifically binds to insulin receptor with considerable affinity (KD-1.17μM) thus activating insulin receptor tyrosine kinase and its downstream signaling molecules resulting increased uptake of [14C] 2 Deoxy-glucose. Oral administration of dmp to streptozotocin treated BALB/c mice lowers blood glucose level and markedly stimulates glucose and fatty acid uptake by skeletal muscle and adipose tissue respectively. In db/db mice, it greatly improves insulin sensitivity through excess expression of PPARγ and its target genes i.e. adiponectin, CD36 and aP2. Study on the underlying mechanism demonstrated that excess expression of Wnt3a decreased PPARγ whereas dmp suppression of Wnt3a gene increased PPARγ expression which subsequently augmented adiponectin. Increased production of adiponectin in db/db mice due to dmp effected lowering of circulatory TG and FFA levels, activates AMPK in skeletal muscle and this stimulates mitochondrial biogenesis and bioenergetics. Decrease of lipid load along with increased mitochondrial activity greatly improves energy homeostasis which has been found to be correlated with the increased insulin sensitivity. The results obtained with dmp, therefore, strongly indicate that dmp could be a potential candidate for insulin replacement therapy. PMID:28072841

  17. Repression of Salmonella enterica phoP expression by small molecules from physiological bile. (United States)

    Antunes, L Caetano M; Wang, Melody; Andersen, Sarah K; Ferreira, Rosana B R; Kappelhoff, Reinhild; Han, Jun; Borchers, Christoph H; Finlay, B Brett


    Infection with Salmonella enterica serovar Typhi in humans causes the life-threatening disease typhoid fever. In the laboratory, typhoid fever can be modeled through the inoculation of susceptible mice with Salmonella enterica serovar Typhimurium. Using this murine model, we previously characterized the interactions between Salmonella Typhimurium and host cells in the gallbladder and showed that this pathogen can successfully invade gallbladder epithelial cells and proliferate. Additionally, we showed that Salmonella Typhimurium can use bile phospholipids to grow at high rates. These abilities are likely important for quick colonization of the gallbladder during typhoid fever and further pathogen dissemination through fecal shedding. To further characterize the interactions between Salmonella and the gallbladder environment, we compared the transcriptomes of Salmonella cultures grown in LB broth or physiological murine bile. Our data showed that many genes involved in bacterial central metabolism are affected by bile, with the citric acid cycle being repressed and alternative respiratory systems being activated. Additionally, our study revealed a new aspect of Salmonella interactions with bile through the identification of the global regulator phoP as a bile-responsive gene. Repression of phoP expression could also be achieved using physiological, but not commercial, bovine bile. The biological activity does not involve PhoPQ sensing of a bile component and is not caused by bile acids, the most abundant organic components of bile. Bioactivity-guided purification allowed the identification of a subset of small molecules from bile that can elicit full activity; however, a single compound with phoP inhibitory activity could not be isolated, suggesting that multiple molecules may act in synergy to achieve this effect. Due to the critical role of phoP in Salmonella virulence, further studies in this area will likely reveal aspects of the interaction between Salmonella

  18. Stem cells and small molecule screening: haploid embryonic stem cells as a new tool

    Institute of Scientific and Technical Information of China (English)

    Bi WU; Wei LI; Liu WANG; Zhong-hua LIU; Xiao-yang ZHAO


    Stem cells can both self-renew and differentiate into various cell types under certain conditions,which makes them a good model for development and disease studies.Recently,chemical approaches have been widely applied in stem cell biology by promoting stem cell self-renewal,proliferation,differentiation and somatic cell reprogramming using specific small molecules.Conversely,stem cells and their derivatives also provide an efficient and robust platform for small molecule and drug screening.Here,we review the current research and applications of small molecules that modulate stem cell self-renewal and differentiation and improve reprogramming,as well as the applications that use stem cells as a tool for small molecule screening.Moreover,we introduce the recent advance in haploid embryonic stem cells research.Haploid embryonic stem cells maintain haploidy and stable growth over extensive passages,possess the ability to differentiate into all three germ layers in vitro and in vivo,and contribute to the germlines of chimeras when injected into blastocysts.Androgenetic haploid stem cells can also be used in place of sperm to produce fertile progeny after intracytoplasmic injection into mature oocytes.Such characteristics demonstrate that haploid stem cells are a new approach for genetic studies at both the cellular and animal levels and that they are a valuable platform for future small molecule screening.

  19. Universal quantum dot-based sandwich-like immunoassay strategy for rapid and ultrasensitive detection of small molecules using portable and reusable optofluidic nano-biosensing platform

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Liping; Zhu, Anna; Lou, Xuening; Song, Dan; Yang, Rong [School of Environment and Natural Resources, Renmin University of China, Beijing (China); Shi, Hanchang [School of Environment, Tsinghua University, Beijing (China); Long, Feng, E-mail: [School of Environment and Natural Resources, Renmin University of China, Beijing (China)


    . - Highlights: • Sandwich-like immunoassay strategy was used for rapid detection of small molecule. • Optofluidic sensing platform investigated the sandwich-like immunoassay mechanism. • A versatile optical biosensor like ELISA was developed using QD-immunoprobe. • No modified primary antibody with highest activity improved biosensor performance. • QD-immunoprobe-based biosensor was highly sensitive for small molecule detection. • Reusable sensing surface was applied for multiple sensing events with low cost.

  20. Development of pharmacophore models for small molecules targeting RNA: Application to the RNA repeat expansion in myotonic dystrophy type 1. (United States)

    Angelbello, Alicia J; González, Àlex L; Rzuczek, Suzanne G; Disney, Matthew D


    RNA is an important drug target, but current approaches to identify bioactive small molecules have been engineered primarily for protein targets. Moreover, the identification of small molecules that bind a specific RNA target with sufficient potency remains a challenge. Computer-aided drug design (CADD) and, in particular, ligand-based drug design provide a myriad of tools to identify rapidly new chemical entities for modulating a target based on previous knowledge of active compounds without relying on a ligand complex. Herein we describe pharmacophore virtual screening based on previously reported active molecules that target the toxic RNA that causes myotonic dystrophy type 1 (DM1). DM1-associated defects are caused by sequestration of muscleblind-like 1 protein (MBNL1), an alternative splicing regulator, by expanded CUG repeats (r(CUG)(exp)). Several small molecules have been found to disrupt the MBNL1-r(CUG)(exp) complex, ameliorating DM1 defects. Our pharmacophore model identified a number of potential lead compounds from which we selected 11 compounds to evaluate. Of the 11 compounds, several improved DM1 defects both in vitro and in cells.

  1. The interaction of small molecules with phospholipid membranes studied by 1H NOESY NMR under magic-angle spinning1

    Institute of Scientific and Technical Information of China (English)

    Holger A SCHEIDT; Daniel HUSTER


    The interaction of small molecules with lipid membranes and the exact knowledge of their binding site and bilayer distribution is of great pharmacological impor-tance and represents an active field of current biophysical research. Over the last decade, a highly resolved 1H solid-state NMR method has been developed that allows measuring localization and distribution of small molecules in membranes. The classical solution 1H NMR NOESY technique is applied to lipid membrane samples under magic-angle spinning (MAS) and NOESY cross-relaxation rates are determined quantitatively. These rates are proportional to the contact probability between molecular segments and therefore an ideal tool to study intermolecular interactions in membranes. Here, we review recent 1H MAS NOESY applications that were carried out to study lateral lipid organization in mixed membranes and the interaction of membranes with water, ethanol, small aromatic compounds, peptides, fluorescence labels, and lipophilic nucleosides.

  2. Small Molecule Binding, Docking, and Characterization of the Interaction between Pth1 and Peptidyl-tRNA

    Directory of Open Access Journals (Sweden)

    Mary C. Hames


    Full Text Available Bacterial Pth1 is essential for viability. Pth1 cleaves the ester bond between the peptide and nucleotide of peptidyl-tRNA generated from aborted translation, expression of mini-genes, and short ORFs. We have determined the shape of the Pth1:peptidyl-tRNA complex using small angle neutron scattering. Binding of piperonylpiperazine, a small molecule constituent of a combinatorial synthetic library common to most compounds with inhibitory activity, was mapped to Pth1 via NMR spectroscopy. We also report computational docking results, modeling piperonylpiperazine binding based on chemical shift perturbation mapping. Overall these studies promote Pth1 as a novel antibiotic target, contribute to understanding how Pth1 interacts with its substrate, advance the current model for cleavage, and demonstrate feasibility of small molecule inhibition.

  3. Saururus cernuus lignans--potent small molecule inhibitors of hypoxia-inducible factor-1. (United States)

    Hossain, Chowdhury Faiz; Kim, Yong-Pil; Baerson, Scott R; Zhang, Lei; Bruick, Richard K; Mohammed, Kaleem A; Agarwal, Ameeta K; Nagle, Dale G; Zhou, Yu-Dong


    Hypoxia-inducible factor-1 (HIF-1) represents an important tumor-selective therapeutic target for solid tumors. In search of novel small molecule HIF-1 inhibitors, 5400 natural product-rich extracts from plants, marine organisms, and microbes were examined for HIF-1 inhibitory activities using a cell-based reporter assay. Bioassay-guided fractionation and isolation, followed by structure elucidation, yielded three potent natural product-derived HIF-1 inhibitors and two structurally related inactive compounds. In a T47D cell-based reporter assay, manassantin B1, manassantin A, and 4-O-methylsaucerneol inhibited hypoxia-induced HIF-1 activation with IC50 values of 3, 3, and 20 nM, respectively. All three compounds are relatively hypoxia-specific inhibitors of HIF-1 activation, in comparison to other stimuli. The hypoxic induction of HIF-1 target genes CDKN1A, VEGF, and GLUT-1 were also inhibited. These compounds inhibit HIF-1 by blocking hypoxia-induced nuclear HIF-1alpha protein accumulation without affecting HIF-1alpha mRNA levels. In addition, preliminary structure-activity studies suggest specific structural requirements for this class of HIF-1 inhibitors.

  4. Saururus cernuus Lignans - Potent Small Molecule Inhibitors of Hypoxia-Inducible Factor-1 (United States)

    Hossain, Chowdhury Faiz; Kim, Yong-Pil; Baerson, Scott R.; Zhang, Lei; Bruick, Richard K.; Mohammed, Kaleem A.; Agarwal, Ameeta K.; Nagle, Dale G.; Zhou, Yu-Dong


    Hypoxia-inducible factor-1 (HIF-1) represents an important tumor-selective therapeutic target for solid tumors. In search of novel small molecule HIF-1 inhibitors, 5400 natural product-rich extracts from plants, marine organisms, and microbes were examined for HIF-1 inhibitory activities using a cell-based reporter assay. Bioassay-guided fractionation and isolation, followed by structure elucidation, yielded three potent natural product-derived HIF-1 inhibitors and two structurally related inactive compounds. In a T47D cell-based reporter assay, manassantin B1, manassantin A, and 4-O-methylsaucerneol inhibited hypoxia-induced HIF-1 activation with IC50 values of 3, 3, and 20 nM, respectively. All three compounds are relatively hypoxia-specific inhibitors of HIF-1 activation, in comparison to other stimuli. The hypoxic induction of HIF-1 target genes CDKN1A, VEGF and GLUT-1 were also inhibited. These compounds inhibit HIF-1 by blocking hypoxia-induced nuclear HIF-1α protein accumulation without affecting HIF-1α mRNA levels. In addition, preliminary structure-activity studies suggest specific structural requirements for this class of HIF-1 inhibitors. PMID:15967416

  5. Human Sarcoma growth is sensitive to small-molecule mediated AXIN stabilization.

    Directory of Open Access Journals (Sweden)

    Alessandra De Robertis

    Full Text Available Sarcomas are mesenchymal tumors showing high molecular heterogeneity, reflected at the histological level by the existence of more than fifty different subtypes. Genetic and epigenetic evidences link aberrant activation of the Wnt signaling to growth and progression of human sarcomas. This phenomenon, mainly accomplished by autocrine loop activity, is sustained by gene amplification, over-expression of Wnt ligands and co-receptors or epigenetic silencing of endogenous Wnt antagonists. We previously showed that pharmacological inhibition of Wnt signaling mediated by Axin stabilization produced in vitro and in vivo antitumor activity in glioblastoma tumors. Here, we report that targeting different sarcoma cell lines with the Wnt inhibitor/Axin stabilizer SEN461 produces a less transformed phenotype, as supported by modulation of anchorage-independent growth in vitro. At the molecular level, SEN461 treatment enhanced the stability of the scaffold protein Axin1, a key negative regulator of the Wnt signaling with tumor suppressor function, resulting in downstream effects coherent with inhibition of canonical Wnt signaling. Genetic phenocopy of small molecule Axin stabilization, through Axin1 over-expression, coherently resulted in strong impairment of soft-agar growth. Importantly, sarcoma growth inhibition through pharmacological Axin stabilization was also observed in a xenograft model in vivo in female CD-1 nude mice. Our findings suggest the usefulness of Wnt inhibitors with Axin stabilization activity as a potentialyl clinical relevant strategy for certain types of sarcomas.

  6. A small-molecule inhibitor of the NLRP3 inflammasome for the treatment of inflammatory diseases. (United States)

    Coll, Rebecca C; Robertson, Avril A B; Chae, Jae Jin; Higgins, Sarah C; Muñoz-Planillo, Raúl; Inserra, Marco C; Vetter, Irina; Dungan, Lara S; Monks, Brian G; Stutz, Andrea; Croker, Daniel E; Butler, Mark S; Haneklaus, Moritz; Sutton, Caroline E; Núñez, Gabriel; Latz, Eicke; Kastner, Daniel L; Mills, Kingston H G; Masters, Seth L; Schroder, Kate; Cooper, Matthew A; O'Neill, Luke A J


    The NOD-like receptor (NLR) family, pyrin domain-containing protein 3 (NLRP3) inflammasome is a component of the inflammatory process, and its aberrant activation is pathogenic in inherited disorders such as cryopyrin-associated periodic syndrome (CAPS) and complex diseases such as multiple sclerosis, type 2 diabetes, Alzheimer's disease and atherosclerosis. We describe the development of MCC950, a potent, selective, small-molecule inhibitor of NLRP3. MCC950 blocked canonical and noncanonical NLRP3 activation at nanomolar concentrations. MCC950 specifically inhibited activation of NLRP3 but not the AIM2, NLRC4 or NLRP1 inflammasomes. MCC950 reduced interleukin-1β (IL-1β) production in vivo and attenuated the severity of experimental autoimmune encephalomyelitis (EAE), a disease model of multiple sclerosis. Furthermore, MCC950 treatment rescued neonatal lethality in a mouse model of CAPS and was active in ex vivo samples from individuals with Muckle-Wells syndrome. MCC950 is thus a potential therapeutic for NLRP3-associated syndromes, including autoinflammatory and autoimmune diseases, and a tool for further study of the NLRP3 inflammasome in human health and disease.

  7. Nonclinical Evaluations of Small-Molecule Oncology Drugs: Integration into Clinical Dose Optimization and Toxicity Management. (United States)

    Dambach, Donna M; Simpson, Natalie E; Jones, Thomas W; Brennan, Richard J; Pazdur, Richard; Palmby, Todd R


    Multidisciplinary approaches that incorporate nonclinical pharmacologic and toxicologic characterization of small-molecule oncology drugs into clinical development programs may facilitate improved benefit-risk profiles and clinical toxicity management in patients. The performance of the current nonclinical safety-testing scheme was discussed, highlighting current strengths and areas for improvement. While current nonclinical testing appears to predict the clinical outcome where the prevalence of specific adverse effects are high, nonclinical testing becomes less reliable for predicting clinical adverse effects that occur infrequently, as with some kinase inhibitors. Although adverse effects associated with kinase inhibitors can often be predicted on the basis of target biology, drugs can be promiscuous and inhibit targets with poorly defined function and associated risks. Improvements in adverse effect databases and better characterization of the biologic activities of drug targets may enable better use of computational modeling approaches in predicting adverse effects with kinase inhibitors. Assessing safety of a lead candidate in parallel with other drug properties enables incorporation of a molecule's best features during chemical design, eliminates the worst molecules early, and permits timely investigation/characterization of toxicity mechanisms for identified liabilities. A safety lead optimization and candidate identification strategy that reduces intrinsic toxicity and metabolic risk and enhances selectivity can deliver selective kinase inhibitors that demonstrate on-target adverse effects identified nonclinically. Integrating clinical and nonclinical data during drug development can facilitate better identification and management of oncology drugs. Follow-up nonclinical studies may be used to better understand the risks in a given patient population and minimize or manage these risks more appropriately. Clin Cancer Res; 22(11); 2618-22. ©2016 AACR SEE ALL

  8. Stimulation of Host Immune Defenses by a Small Molecule Protects C. elegans from Bacterial Infection


    Read Pukkila-Worley; Rhonda Feinbaum; Kirienko, Natalia V; Jonah Larkins-Ford; Conery, Annie L.; Ausubel, Frederick M.


    The nematode Caenorhabditis elegans offers currently untapped potential for carrying out high-throughput, live-animal screens of low molecular weight compound libraries to identify molecules that target a variety of cellular processes. We previously used a bacterial infection assay in C. elegans to identify 119 compounds that affect host-microbe interactions among 37,214 tested. Here we show that one of these small molecules, RPW-24, protects C. elegans from bacterial infection by stimulating...

  9. Suppression of Autoimmune Arthritis by Small Molecule Inhibitors of the JAK/STAT Pathway

    Directory of Open Access Journals (Sweden)

    Charles J. Malemud


    Full Text Available A skewed ratio of pro-inflammatory to anti-inflammatory cytokines, elevated growth factor synthesis and T- and B-lymphocyte activation are 3 hallmarks of rheumatoid arthritis (RA pathology. Interleukin-6 (IL-6, IL-7, IL-17, IL-12/IL-23 and growth factors, granulocyte macrophage-colony stimulating factor, IL-3, and erythropoietin activate the Janus Kinase/Signal Transducers and Activators of Transcription (JAK/STAT pathway. Evidence showed that STAT protein phosphorylation (p-STAT by activated JAKs is permissive for p-STAT to act as transcription factors by binding to STAT-responsive gene promoter sequences. This event is critical for perpetuating RA, in part, by up-regulating pro-inflammatory cytokine gene transcription. Activation of JAK/STAT by cytokines and growth factors can induce ‘cross-talk’ with other signaling pathways by which Stress-Activated Protein/Mitogen-Activated Protein Kinase (SAP/MAPK and Phosphatidylinositide-3-Kinase (PI3K-mediated signaling are also activated. JAK-specific small molecule inhibitors (SMIs were developed to test whether JAK/STAT pathway blockade would regulate autoimmune-mediated inflammation. JAK-specific SMI blockade inhibited p-STAT induced by pro-inflammatory cytokines in vitro. Systemically administered JAK-specific SMI blockade also ameliorated biomarkers of inflammation in well-validated arthritis animal models. A few JAK-specific SMIs have made their way into RA clinical trials. In fact, the JAK3-specific SMI, CP-690,500 is the first JAK/STAT SMI to be assessed for clinical efficacy in a Phase III RA trial.

  10. Structural Effects of Small Molecules on Phospholipid Bilayers Investigated by Molecular Simulations

    CERN Document Server

    Lee, B W; Sum, A K; Vattulainen, I; Patra, M; Karttunen, M; Lee, Bryan W; Faller, Roland; Sum, Amadeu K; Vattulainen, Ilpo; Patra, Michael; Karttunen, Mikko


    We summarize and compare recent Molecular Dynamics simulations on the interactions of dipalmitoylphosphatidylcholine (DPPC) bilayers in the liquid crystalline phase with a number of small molecules including trehalose, a disaccharide of glucose, alcohols, and dimethylsulfoxide (DMSO). The sugar molecules tend to stabilize the structure of the bilayer as they bridge adjacent lipid headgroups. They do not strongly change the structure of the bilayer. Alcohols and DMSO destabilize the bilayer as they increase its area per molecule in the bilayer plane and decrease the order parameter. Alcohols have a stronger detrimental effect than DMSO. The observables which we compare are the area per molecule in the plane of the bilayer, the membrane thickness, and the NMR order parameter of DPPC hydrocarbon tails. The area per molecule and the order parameter are very well correlated whereas the bilayer thickness is not necessarily correlated with them.

  11. Exploration of the spontaneous fluctuating activity of single enzyme molecules

    NARCIS (Netherlands)

    Schwabe, A.; Maarleveld, T.R.; Bruggeman, F.J.


    Single enzyme molecules display inevitable, stochastic fluctuations in their catalytic activity. In metabolism, for instance, the stochastic activity of individual enzymes is averaged out due to their high copy numbers per single cell. However, many processes inside cells rely on single enzyme activ

  12. Precise small-molecule recognition of a toxic CUG RNA repeat expansion. (United States)

    Rzuczek, Suzanne G; Colgan, Lesley A; Nakai, Yoshio; Cameron, Michael D; Furling, Denis; Yasuda, Ryohei; Disney, Matthew D


    Excluding the ribosome and riboswitches, developing small molecules that selectively target RNA is a longstanding problem in chemical biology. A typical cellular RNA is difficult to target because it has little tertiary, but abundant secondary structure. We designed allele-selective compounds that target such an RNA, the toxic noncoding repeat expansion (r(CUG)(exp)) that causes myotonic dystrophy type 1 (DM1). We developed several strategies to generate allele-selective small molecules, including non-covalent binding, covalent binding, cleavage and on-site probe synthesis. Covalent binding and cleavage enabled target profiling in cells derived from individuals with DM1, showing precise recognition of r(CUG)(exp). In the on-site probe synthesis approach, small molecules bound adjacent sites in r(CUG)(exp) and reacted to afford picomolar inhibitors via a proximity-based click reaction only in DM1-affected cells. We expanded this approach to image r(CUG)(exp) in its natural context.

  13. Synthetic Small Molecule Inhibitors of Hh Signaling As Anti-Cancer Chemotherapeutics (United States)

    Maschinot, C.A.; Pace, J.R.; Hadden, M.K.


    The hedgehog (Hh) pathway is a developmental signaling pathway that is essential to the proper embryonic development of many vertebrate systems. Dysregulation of Hh signaling has been implicated as a causative factor in the development and progression of several forms of human cancer. As such, the development of small molecule inhibitors of Hh signaling as potential anti-cancer chemotherapeutics has been a major area of research interest in both academics and industry over the past ten years. Through these efforts, synthetic small molecules that target multiple components of the Hh pathway have been identified and advanced to preclinical or clinical development. The goal of this review is to provide an update on the current status of several synthetic small molecule Hh pathway inhibitors and explore the potential of several recently disclosed inhibitory scaffolds. PMID:26310919

  14. Small Molecule Metabolite Biomarker Candidates in Urine from Mice Exposed to Formaldehyde

    Directory of Open Access Journals (Sweden)

    Juan Zhang


    Full Text Available Formaldehyde (FA is a ubiquitous compound used in a wide variety of industries, and is also a major indoor pollutant emitted from building materials, furniture, etc. Because FA is rapidly metabolized and endogenous to many materials, specific biomarkers for exposure have not been identified. In this study, we identified small metabolite biomarkers in urine that might be related FA exposure. Mice were allowed to inhale FA (0, 4, 8 mg/m3 6 h per day for 7 consecutive days, and urine samples were collected on the 7th day of exposure. Liquid chromatography coupled with time of flight-mass spectrometry and principal component analysis (PCA was applied to determine alterations of endogenous metabolites in urine. Additionally, immune toxicity studies were conducted to ensure that any resultant toxic effects could be attributed to inhalation of FA. The results showed a significant decrease in the relative rates of T lymphocyte production in the spleen and thymus of mice exposed to FA. Additionally, decreased superoxide dismutase activity and increased reactive oxygen species levels were found in the isolated spleen cells of exposed mice. A total of 12 small molecules were found to be altered in the urine, and PCA analysis showed that urine from the control and FA exposed groups could be distinguished from each other based on the altered molecules. Hippuric acid and cinnamoylglycine were identified in urine using exact mass and fragment ions. Our results suggest that the pattern of metabolites found in urine is significantly changed following FA inhalation, and hippuric acid and cinnamoylglycine might represent potential biomarker candidates for FA exposure.

  15. Concentration-related response potentiometric titrations to study the interaction of small molecules with large biomolecules. (United States)

    Hamidi-Asl, Ezat; Daems, Devin; De Wael, Karolien; Van Camp, Guy; Nagels, Luc J


    In the present paper, the utility of a special potentiometric titration approach for recognition and calculation of biomolecule/small-molecule interactions is reported. This approach is fast, sensitive, reproducible, and inexpensive in comparison to the other methods for the determination of the association constant values (Ka) and the interaction energies (ΔG). The potentiometric titration measurement is based on the use of a classical polymeric membrane indicator electrode in a solution of the small-molecule ligand. The biomolecule is used as a titrant. The potential is measured versus a reference electrode and transformed into a concentration-related signal over the entire concentration interval, also at low concentrations, where the millivolt (y-axis) versus log canalyte (x-axis) potentiometric calibration curve is not linear. In the procedure, Ka is calculated for the interaction of cocaine with a cocaine binding aptamer and with an anticocaine antibody. To study the selectivity and cross-reactivity, other oligonucleotides and aptamers are tested, as well as other small ligand molecules such as tetrakis(4-chlorophenyl)borate, metergoline, lidocaine, and bromhexine. The calculated Ka compared favorably to the value reported in the literature using surface plasmon resonance. The potentiometric titration approach called "concentration-related response potentiometry" is used to study molecular interaction for seven macromolecular target molecules and four small-molecule ligands.

  16. New blue emissive conjugated small molecules with low lying HOMO energy levels for optoelectronic applications (United States)

    Trupthi Devaiah, C.; Hemavathi, B.; Ahipa, T. N.


    Versatile conjugated small molecules bearing cyanopyridone core (CP1-5), composed of various donor/acceptor moieties at position - 4 and - 6 have been designed, developed and characterized. Their solvatochromic studies were conducted and analyzed using Lippert-Mataga, Kamlet-Taft and Catalan solvent scales and interesting results were obtained. The polarizability/dipolarity of the solvent greatly influenced the spectra. The electrochemical studies were carried out using cyclic voltammetry to calculate the HOMO-LUMO energy levels. The study revealed that the synthesized conjugated small molecules possess low lying HOMO energy levels which can be exploited for application in various fields of optoelectronics.

  17. Design, synthesis and selection of DNA-encoded small-molecule libraries. (United States)

    Clark, Matthew A; Acharya, Raksha A; Arico-Muendel, Christopher C; Belyanskaya, Svetlana L; Benjamin, Dennis R; Carlson, Neil R; Centrella, Paolo A; Chiu, Cynthia H; Creaser, Steffen P; Cuozzo, John W; Davie, Christopher P; Ding, Yun; Franklin, G Joseph; Franzen, Kurt D; Gefter, Malcolm L; Hale, Steven P; Hansen, Nils J V; Israel, David I; Jiang, Jinwei; Kavarana, Malcolm J; Kelley, Michael S; Kollmann, Christopher S; Li, Fan; Lind, Kenneth; Mataruse, Sibongile; Medeiros, Patricia F; Messer, Jeffrey A; Myers, Paul; O'Keefe, Heather; Oliff, Matthew C; Rise, Cecil E; Satz, Alexander L; Skinner, Steven R; Svendsen, Jennifer L; Tang, Lujia; van Vloten, Kurt; Wagner, Richard W; Yao, Gang; Zhao, Baoguang; Morgan, Barry A


    Biochemical combinatorial techniques such as phage display, RNA display and oligonucleotide aptamers have proven to be reliable methods for generation of ligands to protein targets. Adapting these techniques to small synthetic molecules has been a long-sought goal. We report the synthesis and interrogation of an 800-million-member DNA-encoded library in which small molecules are covalently attached to an encoding oligonucleotide. The library was assembled by a combination of chemical and enzymatic synthesis, and interrogated by affinity selection. We describe methods for the selection and deconvolution of the chemical display library, and the discovery of inhibitors for two enzymes: Aurora A kinase and p38 MAP kinase.

  18. Small-molecule control of cytokine function: new opportunities for treating immune disorders (United States)

    Sundberg, Thomas B.; Xavier, Ramnik J.; Schreiber, Stuart L.; Shamji, Alykhan F.


    Manipulating cytokine function with protein-based drugs has proven effective for treating a wide variety of autoimmune and auto-inflammatory disorders. However, the limited ability of protein-based drugs to modulate intracellular targets, including many implicated by studies of the genetics and physiology of these diseases, and to coordinately neutralize redundant inflammatory cytokines, suggest an important and complementary role for small molecules in immunomodulatory drug development. The recent clinical approval of Janus kinase and phosphodiesterase inhibitors, along with emerging evidence from other compound classes, firmly establish small molecules as effective tools for modulating therapeutically relevant proteins that give rise to aberrant cytokine signaling or mediate its downstream consequences. PMID:25222143

  19. Dynamic Variation in Protein-Small Molecule Interaction Observed by Double-Nanohole Optical Trapping

    CERN Document Server

    Balushi, Ahmed Al


    The interaction of proteins with small molecules is fundamental to their function in living organisms and it is widely studied in drug development. Here we compare optical trapping dynamics of streptavidin and biotinylated streptavidin using a double nanohole optical trap in a metal film. Consistent and clearly distinct behavior is seen between the protein with and without the small molecule binding. The real-time dynamics at the single protein level are accessible with this technique, which also has advantages of not requiring tethering to a surface or the need for exogeneous markers.

  20. Small-molecule library screening by docking with PyRx. (United States)

    Dallakyan, Sargis; Olson, Arthur J


    Virtual molecular screening is used to dock small-molecule libraries to a macromolecule in order to find lead compounds with desired biological function. This in silico method is well known for its application in computer-aided drug design. This chapter describes how to perform small-molecule virtual screening by docking with PyRx, which is open-source software with an intuitive user interface that runs on all major operating systems (Linux, Windows, and Mac OS). Specific steps for using PyRx, as well as considerations for data preparation, docking, and data analysis, are also described.


    Institute of Scientific and Technical Information of China (English)

    Chi-fei Wu


    A novel transition appeared above the glass transition temperature of chlorinated polyethylene (CPE) for binary blends of CPE and additives such as organic small molecules or oligomers. This transition was assigned to the dissociation of intermolecular hydrogen bonds between the polymer and additive within the additive rich phase. Of particular interest is that a novel pyramid crystal was observed in the annealed CPE/hindered phenol blends. Another intriguing observation is that these polymer/small molecule blends organized by intermolecular hydrogen bonding have several potential properties, such as shape-memorization, self-restoration, self-adhesiveness and super damping.``

  2. American Chemical Society--238th National Meeting & Exposition. Novel small molecule therapeutics. 16-20 August 2009, Washington DC, USA. (United States)

    Rotella, David P


    The Novel Small Molecule Therapeutics session of the American Chemical Society 238th National Meeting and Exposition, held in Washington DC, included topics covering new therapeutic developments in CNS, anti-infective, cardiovascular and anti-inflammatory applications. This conference report highlights selected presentations on PAR2 (protease-activated receptor 2) antagonists, adenosine and P2Y receptor agonists and antagonists, antimicrobials and neuroprotective compounds.

  3. The small molecule harmine regulates NFATc1 and Id2 expression in osteoclast progenitor cells. (United States)

    Egusa, Hiroshi; Doi, Masanori; Saeki, Makio; Fukuyasu, Sho; Akashi, Yoshihiro; Yokota, Yoshifumi; Yatani, Hirofumi; Kamisaki, Yoshinori


    Small molecule compounds that potently affect osteoclastogenesis could be useful as chemical probes for elucidating the mechanisms of various biological phenomena and as effective therapeutic strategies against bone resorption. An osteoclast progenitor cell-based high-throughput screening system was designed to target activation of NFAT, which is a key event for osteoclastogenesis. Orphan ligand library screening using this system identified the β-carboline derivative harmine, which is a highly potent inhibitor of dual-specificity tyrosine-phosphorylation regulated kinase 1A (DYRK1A), to be an NFAT regulator in osteoclasts. RAW264.7 cells highly expressed DYRK1A protein, and in vitro phosphorylation assay demonstrated that harmine directly inhibited the DYRK1A-mediated phosphorylation (in-activation) of NFATc1. Harmine promoted the dephosphorylation (activation) of NFATc1 in RAW264.7 cells within 24h, and it significantly increased the expression of NFATc1 in RAW264.7 cells and mouse primary bone marrow macrophages (BMMs) both in the presence and absence of RANKL stimulation. Although harmine promoted NFATc1 expression and stimulated target genes for osteoclastogenesis, cell-cell fusion and the formation of TRAP-positive multinucleated osteoclasts from RAW264.7 cells and BMMs was significantly inhibited by harmine treatment. Meanwhile, harmine remarkably promoted the expression of inhibitor of DNA binding/differentiation-2 (Id2), which is a negative regulator for osteoclastogenesis, in RAW264.7 cells and BMMs. An Id2-null-mutant showed slightly increased osteoclast formation from BMMs, and the harmine-mediated inhibition of osteoclast formation was abolished in the BMMs of Id2-null-mutant mice. These results suggest that harmine is a potent activator of NFATc1 that interferes with the function of DYRK1A in osteoclast precursors and also up-regulates Id2 protein, which may dominantly inhibit expression pathways associated with cell-cell fusion, thereby leading to

  4. HIV capsid is a tractable target for small molecule therapeutic intervention.

    Directory of Open Access Journals (Sweden)

    Wade S Blair

    Full Text Available Despite a high current standard of care in antiretroviral therapy for HIV, multidrug-resistant strains continue to emerge, underscoring the need for additional novel mechanism inhibitors that will offer expanded therapeutic options in the clinic. We report a new class of small molecule antiretroviral compounds that directly target HIV-1 capsid (CA via a novel mechanism of action. The compounds exhibit potent antiviral activity against HIV-1 laboratory strains, clinical isolates, and HIV-2, and inhibit both early and late events in the viral replication cycle. We present mechanistic studies indicating that these early and late activities result from the compound affecting viral uncoating and assembly, respectively. We show that amino acid substitutions in the N-terminal domain of HIV-1 CA are sufficient to confer resistance to this class of compounds, identifying CA as the target in infected cells. A high-resolution co-crystal structure of the compound bound to HIV-1 CA reveals a novel binding pocket in the N-terminal domain of the protein. Our data demonstrate that broad-spectrum antiviral activity can be achieved by targeting this new binding site and reveal HIV CA as a tractable drug target for HIV therapy.

  5. Rational Design of Diketopyrrolopyrrole-Based Small Molecules as Donating Materials for Organic Solar Cells (United States)

    Jin, Ruifa; Wang, Kai


    A series of diketopyrrolopyrrole-based small molecules have been designed to explore their optical, electronic, and charge transport properties as organic solar cell (OSCs) materials. The calculation results showed that the designed molecules can lower the band gap and extend the absorption spectrum towards longer wavelengths. The designed molecules own the large longest wavelength of absorption spectra, the oscillator strength, and absorption region values. The optical, electronic, and charge transport properties of the designed molecules are affected by the introduction of different π-bridges and end groups. We have also predicted the mobility of the designed molecule with the lowest total energies. Our results reveal that the designed molecules are expected to be promising candidates for OSC materials. Additionally, the designed molecules are expected to be promising candidates for electron and/or hole transport materials. On the basis of our results, we suggest that molecules under investigation are suitable donors for [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and its derivatives as acceptors of OSCs. PMID:26343640

  6. Targeting Cyclin-Dependent Kinases in Human Cancers: From Small Molecules to Peptide Inhibitors

    Directory of Open Access Journals (Sweden)

    Marion Peyressatre


    Full Text Available Cyclin-dependent kinases (CDK/Cyclins form a family of heterodimeric kinases that play central roles in regulation of cell cycle progression, transcription and other major biological processes including neuronal differentiation and metabolism. Constitutive or deregulated hyperactivity of these kinases due to amplification, overexpression or mutation of cyclins or CDK, contributes to proliferation of cancer cells, and aberrant activity of these kinases has been reported in a wide variety of human cancers. These kinases therefore constitute biomarkers of proliferation and attractive pharmacological targets for development of anticancer therapeutics. The structural features of several of these kinases have been elucidated and their molecular mechanisms of regulation characterized in depth, providing clues for development of drugs and inhibitors to disrupt their function. However, like most other kinases, they constitute a challenging class of therapeutic targets due to their highly conserved structural features and ATP-binding pocket. Notwithstanding, several classes of inhibitors have been discovered from natural sources, and small molecule derivatives have been synthesized through rational, structure-guided approaches or identified in high throughput screens. The larger part of these inhibitors target ATP pockets, but a growing number of peptides targeting protein/protein interfaces are being proposed, and a small number of compounds targeting allosteric sites have been reported.

  7. Novel protein kinase signaling systems regulating lifespan identified by small molecule library screening using Drosophila.

    Directory of Open Access Journals (Sweden)

    Stephen R Spindler

    Full Text Available Protein kinase signaling cascades control most aspects of cellular function. The ATP binding domains of signaling protein kinases are the targets of most available inhibitors. These domains are highly conserved from mammals to flies. Herein we describe screening of a library of small molecule inhibitors of protein kinases for their ability to increase Drosophila lifespan. We developed an assay system which allowed screening using the small amounts of materials normally present in commercial chemical libraries. The studies identified 17 inhibitors, the majority of which targeted tyrosine kinases associated with the epidermal growth factor receptor (EGFR, platelet-derived growth factor (PDGF/vascular endothelial growth factor (VEGF receptors, G-protein coupled receptor (GPCR, Janus kinase (JAK/signal transducer and activator of transcription (STAT, the insulin and insulin-like growth factor (IGFI receptors. Comparison of the protein kinase signaling effects of the inhibitors in vitro defined a consensus intracellular signaling profile which included decreased signaling by p38MAPK (p38, c-Jun N-terminal kinase (JNK and protein kinase C (PKC. If confirmed, many of these kinases will be novel additions to the signaling cascades known to regulate metazoan longevity.

  8. Novel protein kinase signaling systems regulating lifespan identified by small molecule library screening using Drosophila. (United States)

    Spindler, Stephen R; Li, Rui; Dhahbi, Joseph M; Yamakawa, Amy; Sauer, Frank


    Protein kinase signaling cascades control most aspects of cellular function. The ATP binding domains of signaling protein kinases are the targets of most available inhibitors. These domains are highly conserved from mammals to flies. Herein we describe screening of a library of small molecule inhibitors of protein kinases for their ability to increase Drosophila lifespan. We developed an assay system which allowed screening using the small amounts of materials normally present in commercial chemical libraries. The studies identified 17 inhibitors, the majority of which targeted tyrosine kinases associated with the epidermal growth factor receptor (EGFR), platelet-derived growth factor (PDGF)/vascular endothelial growth factor (VEGF) receptors, G-protein coupled receptor (GPCR), Janus kinase (JAK)/signal transducer and activator of transcription (STAT), the insulin and insulin-like growth factor (IGFI) receptors. Comparison of the protein kinase signaling effects of the inhibitors in vitro defined a consensus intracellular signaling profile which included decreased signaling by p38MAPK (p38), c-Jun N-terminal kinase (JNK) and protein kinase C (PKC). If confirmed, many of these kinases will be novel additions to the signaling cascades known to regulate metazoan longevity.

  9. MicroRNA: a small molecule with a big biological impact. (United States)

    Zhou, Xiaofeng; Yang, Pan-Chyr


    One of the most significant achievements in biological science in the last decade is the discovery of RNA interference (RNAi), a process within living cells that regulates gene expression at post-transcriptional levels. Historically, this process was described by other more generic names, such as co-suppression and post transcriptional gene silencing. Only after the molecular mechanism underlying these apparently unrelated processes was fully understood did it become apparent that they all described the RNAi phenomenon. In 2006, Dr. Andrew Fire and Dr. Craig C. Mello were awarded the Nobel Prize in Physiology or Medicine for their work on RNAi interference. RNAi is an RNA-dependent gene silencing process that is controlled by the RNA-induced silencing complex (RISC) and is initiated by two types of small RNA molecules - microRNA (miRNA) and small interfering RNA (siRNA). However, the function of microRNA appears to be far beyond RNAi alone, including direct interaction with the gene promoter and epigenetic regulation of the DNA methylation and histone modification. By regulating gene expression, miRNAs are likely to be involved in diverse biological activities, such as tumorigenesis, immune response, insulin secretion, neurotransmitter synthesis, and circadian rhythm, to name a few. MicroRNAs are 21-23 nucleotide single stranded RNA molecules found in eukaryotic cells. The first miRNA, lin-4, was characterized in C. elegans in the early 1990s [1]. In the early years, the progress on microRNA research was slow and experienced substantial growing pains. The short length and uniqueness of each microRNA rendered many conventional hybridization based methods ineffective; very small RNAs are difficult to reliably amplify or label without introducing bias. In addition, hybridization-based methods for microRNA profiling relied on probes designed to detect known microRNAs or known microRNA species previously identified by sequencing or homology search. Recent evidence of

  10. Ani9, A Novel Potent Small-Molecule ANO1 Inhibitor with Negligible Effect on ANO2.

    Directory of Open Access Journals (Sweden)

    Yohan Seo

    Full Text Available Anoctamin1 (ANO1/transmembrane protein 16A (TMEM16A, a calcium-activated chloride channel (CaCC, is involved in many physiological functions such as fluid secretion, smooth muscle contraction, nociception and cancer progression. To date, only a few ANO1 inhibitors have been described, and these have low potency and selectivity for ANO1. Here, we performed a high-throughput screening to identify highly potent and selective small molecule inhibitors of ANO1. Three novel ANO1 inhibitors were discovered from screening of 54,400 synthetic small molecules, and they were found to fully block ANO1 channel activity with an IC50 < 3 μM. Electrophysiological analysis revealed that the most potent inhibitor, 2-(4-chloro-2-methylphenoxy-N-[(2-methoxyphenylmethylideneamino]-acetamide (Ani9, completely inhibited ANO1 chloride current with submicromolar potency. Notably, unlike previous small-molecule ANO1 inhibitors identified to date, Ani9 displayed high selectivity for ANO1 as compared to ANO2, which shares a high amino acid homology to ANO1. In addition, Ani9 did not affect the intracellular calcium signaling and CFTR chloride channel activity. Our results suggest that Ani9 may be a useful pharmacological tool for studying ANO1 and a potential development candidate for drug therapy of cancer, hypertension, pain, diarrhea and asthma.

  11. Sustained release of small molecules from carbon nanotube-reinforced monetite calcium phosphate cement. (United States)

    Lin, Boren; Zhou, Huan; Leaman, Douglas W; Goel, Vijay K; Agarwal, Anand K; Bhaduri, Sarit B


    The interest in developing calcium phosphate cement (CPC) as a drug delivery system has risen because of its capability to achieve local and controlled treatment to the site of the bone disease. The purpose of this study was to investigate the release pattern of drug-carrying carboxylic acid-functionalized multi-walled carbon nanotube (MWCNT)-reinforced monetite (DCPA, CaHPO4)-based CPC. Z-Leu-Leu-Leu-al (MG132), a small peptide molecule inhibiting NF-κB-mediated osteoclastic resorption, was used as a model drug. MG132 was added into the cement during setting and released into the medium used to culture indicator cells. Significant cell death was observed in osteoblast MC3T3-E1 cells cultured in the medium incubated with MG132-loaded CPC; however, with the presence of MWCNTs in the cement, the toxic effect was not detectable. NF-κB activation was quantified using a NF-κB promoter-driving luciferase reporter in human embryonic kidney 293 cells. The medium collected after incubation with drug-incorporated CPC with or without MWCNT inhibited TNFα-induced NF-κB activation indicating that the effective amount of MG132 was released. CPC/drug complex showed a rapid release within 24h whereas incorporation of MWCNTs attenuated this burst release effect. In addition, suppression of TNFα-induced osteoclast differentiation in RAW 264.7 cell culture also confirmed the sustained release of MWCNT/CPC/drug. Our data demonstrated the drug delivery capability of this cement composite, which can potentially be used to carry therapeutic molecules to improve bone regeneration in conjunction with its fracture stabilizing function. Furthermore, it suggested a novel approach to lessen the burst release effect of the CPC-based drug delivery system by incorporating functionalized MWCNTs.

  12. Rational Design of Small-Molecule Stabilizers of Spermine Synthase Dimer by Virtual Screening and Free Energy-Based Approach (United States)

    Zhang, Zhe; Martiny, Virginie; Lagorce, David; Ikeguchi, Yoshihiko; Alexov, Emil; Miteva, Maria A.


    Snyder-Robinson Syndrome (SRS) is a rare mental retardation disorder which is caused by the malfunctioning of an enzyme, the spermine synthase (SMS), which functions as a homo-dimer. The malfunctioning of SMS in SRS patients is associated with several identified missense mutations that occur away from the active site. This investigation deals with a particular SRS-causing mutation, the G56S mutation, which was shown computationally and experimentally to destabilize the SMS homo-dimer and thus to abolish SMS enzymatic activity. As a proof-of-concept, we explore the possibility to restore the enzymatic activity of the malfunctioning SMS mutant G56S by stabilizing the dimer through small molecule binding at the mutant homo-dimer interface. For this purpose, we designed an in silico protocol that couples virtual screening and a free binding energy-based approach to identify potential small-molecule binders on the destabilized G56S dimer, with the goal to stabilize it and thus to increase SMS G56S mutant activity. The protocol resulted in extensive list of plausible stabilizers, among which we selected and tested 51 compounds experimentally for their capability to increase SMS G56S mutant enzymatic activity. In silico analysis of the experimentally identified stabilizers suggested five distinctive chemical scaffolds. This investigation suggests that druggable pockets exist in the vicinity of the mutation sites at protein-protein interfaces which can be used to alter the disease-causing effects by small molecule binding. The identified chemical scaffolds are drug-like and can serve as original starting points for development of lead molecules to further rescue the disease-causing effects of the Snyder-Robinson syndrome for which no efficient treatment exists up to now. PMID:25340632

  13. Rational design of small-molecule stabilizers of spermine synthase dimer by virtual screening and free energy-based approach.

    Directory of Open Access Journals (Sweden)

    Zhe Zhang

    Full Text Available Snyder-Robinson Syndrome (SRS is a rare mental retardation disorder which is caused by the malfunctioning of an enzyme, the spermine synthase (SMS, which functions as a homo-dimer. The malfunctioning of SMS in SRS patients is associated with several identified missense mutations that occur away from the active site. This investigation deals with a particular SRS-causing mutation, the G56S mutation, which was shown computationally and experimentally to destabilize the SMS homo-dimer and thus to abolish SMS enzymatic activity. As a proof-of-concept, we explore the possibility to restore the enzymatic activity of the malfunctioning SMS mutant G56S by stabilizing the dimer through small molecule binding at the mutant homo-dimer interface. For this purpose, we designed an in silico protocol that couples virtual screening and a free binding energy-based approach to identify potential small-molecule binders on the destabilized G56S dimer, with the goal to stabilize it and thus to increase SMS G56S mutant activity. The protocol resulted in extensive list of plausible stabilizers, among which we selected and tested 51 compounds experimentally for their capability to increase SMS G56S mutant enzymatic activity. In silico analysis of the experimentally identified stabilizers suggested five distinctive chemical scaffolds. This investigation suggests that druggable pockets exist in the vicinity of the mutation sites at protein-protein interfaces which can be used to alter the disease-causing effects by small molecule binding. The identified chemical scaffolds are drug-like and can serve as original starting points for development of lead molecules to further rescue the disease-causing effects of the Snyder-Robinson syndrome for which no efficient treatment exists up to now.

  14. A density functional study on the adsorption of hydrogen molecule onto small copper clusters

    Indian Academy of Sciences (India)

    Xiang-Jun Kuang; Xin-Qiang Wang; Gao-Bin Liu


    An all-electron scalar relativistic calculation on the adsorption of hydrogen molecule onto small copper clusters has been performed by using density functional theory with the generalized gradient approximation (GGA) at PW91 level. Our results reveal that after adsorption of H2 molecule, the Cu-Cu interaction is strengthened and the H-H interaction is weakened, the reactivity enhancement of H2 molecule is obvious. The VIPs, HLGs and VEAs of CuH2 clusters show an obvious odd-even oscillation. It is suggested that the H2 molecule is more favourable to be adsorbed by the even-numbered small copper clusters. Meanwhile, the odd-even alteration of magnetic moments is also observed and may be served as the material with tunable code capacity of `0’ and `1' by adsorbing hydrogen molecule onto odd or even-numbered small copper clusters. Some discrepancies of dissociative adsorption between our work and previous works are found and may be understood in terms of the electron pairing effect and the scalar relativistic effect.

  15. Prediction of small molecules' metabolic pathways based on functional group composition. (United States)

    Lu, Jin; Niu, Bing; Liu, Liang; Lu, Wen-Cong; Cai, Yu-Dong


    How to correctly and efficiently determine small molecules' biological function is a challenge and has a positive effect on further metabonomics analysis. Here, we introduce a computational approach to address this problem. The new approach is based on AdaBoost method and featured by function group composition to the metabolic pathway analysis, which can fast and automatically map the small chemical molecules back to the possible metabolic pathway that they belong to. As a result, jackknife cross validation test and independent set test on the model reached 73.7% and 73.8%, respectively. It can be concluded that the current approach is very promising for mapping some unknown molecules' possible metabolic pathway. An online predictor developed by this research is available at

  16. Controlling conformations of conjugated polymers and small molecules: the role of nonbonding interactions. (United States)

    Jackson, Nicholas E; Savoie, Brett M; Kohlstedt, Kevin L; Olvera de la Cruz, Monica; Schatz, George C; Chen, Lin X; Ratner, Mark A


    The chemical variety present in the organic electronics literature has motivated us to investigate potential nonbonding interactions often incorporated into conformational "locking" schemes. We examine a variety of potential interactions, including oxygen-sulfur, nitrogen-sulfur, and fluorine-sulfur, using accurate quantum-chemical wave function methods and noncovalent interaction (NCI) analysis on a selection of high-performing conjugated polymers and small molecules found in the literature. In addition, we evaluate a set of nonbonding interactions occurring between various heterocyclic and pendant atoms taken from a group of representative π-conjugated molecules. Together with our survey and set of interactions, it is determined that while many nonbonding interactions possess weak binding capabilities, nontraditional hydrogen-bonding interactions, oxygen-hydrogen (CH···O) and nitrogen-hydrogen (CH···N), are alone in inducing conformational control and enhanced planarity along a polymer or small molecule backbone at room temperature.

  17. Using nonlocal electrostatics for solvation free energy computations ions and small molecules

    CERN Document Server

    Hildebrandt, A; Blossey, R; Lenhof, H P


    Solvation free energy is an important quantity in Computational Chemistry with a variety of applications, especially in drug discovery and design. The accurate prediction of solvation free energies of small molecules in water is still a largely unsolved problem, which is mainly due to the complex nature of the water-solute interactions. In this letter we develop a scheme for the determination of the electrostatic contribution to the solvation free energy of charged molecules based on nonlocal electrostatics involving a minimal parameter set which in particular allows to introduce atomic radii in a consistent way. We test our approach on simple ions and small molecules for which both experimental results and other theoretical descriptions are available for quantitative comparison. We conclude that our approach is both physically transparent and quantitatively reliable.

  18. Small Molecule Drug Discovery at the Glucagon-Like Peptide-1 Receptor

    Directory of Open Access Journals (Sweden)

    Francis S. Willard


    Full Text Available The therapeutic success of peptide glucagon-like peptide-1 (GLP-1 receptor agonists for the treatment of type 2 diabetes mellitus has inspired discovery efforts aimed at developing orally available small molecule GLP-1 receptor agonists. Although the GLP-1 receptor is a member of the structurally complex class B1 family of GPCRs, in recent years, a diverse array of orthosteric and allosteric nonpeptide ligands has been reported. These compounds include antagonists, agonists, and positive allosteric modulators with intrinsic efficacy. In this paper, a comprehensive review of currently disclosed small molecule GLP-1 receptor ligands is presented. In addition, examples of “ligand bias” and “probe dependency” for the GLP-1 receptor are discussed; these emerging concepts may influence further optimization of known molecules or persuade designs of expanded screening strategies to identify novel chemical starting points for GLP-1 receptor drug discovery.

  19. Alkyne-tag Raman imaging for visualization of mobile small molecules in live cells. (United States)

    Yamakoshi, Hiroyuki; Dodo, Kosuke; Palonpon, Almar; Ando, Jun; Fujita, Katsumasa; Kawata, Satoshi; Sodeoka, Mikiko


    Alkyne has a unique Raman band that does not overlap with Raman scattering from any endogenous molecule in live cells. Here, we show that alkyne-tag Raman imaging (ATRI) is a promising approach for visualizing nonimmobilized small molecules in live cells. An examination of structure-Raman shift/intensity relationships revealed that alkynes conjugated to an aromatic ring and/or to a second alkyne (conjugated diynes) have strong Raman signals in the cellular silent region and can be excellent tags. Using these design guidelines, we synthesized and imaged a series of alkyne-tagged coenzyme Q (CoQ) analogues in live cells. Cellular concentrations of diyne-tagged CoQ analogues could be semiquantitatively estimated. Finally, simultaneous imaging of two small molecules, 5-ethynyl-2'-deoxyuridine (EdU) and a CoQ analogue, with distinct Raman tags was demonstrated.

  20. Selecting, Acquiring, and Using Small Molecule Libraries for High-Throughput Screening. (United States)

    Dandapani, Sivaraman; Rosse, Gerard; Southall, Noel; Salvino, Joseph M; Thomas, Craig J

    The selection, acquisition and use of high quality small molecule libraries for screening is an essential aspect of drug discovery and chemical biology programs. Screening libraries continue to evolve as researchers gain a greater appreciation of the suitability of small molecules for specific biological targets, processes and environments. The decisions surrounding the make-up of any given small molecule library is informed by a multitude of variables and opinions vary on best-practices. The fitness of any collection relies upon upfront filtering to avoiding problematic compounds, assess appropriate physicochemical properties, install the ideal level of structural uniqueness and determine the desired extent of molecular complexity. These criteria are under constant evaluation and revision as academic and industrial organizations seek out collections that yield ever improving results from their screening portfolios. Practical questions including cost, compound management, screening sophistication and assay objective also play a significant role in the choice of library composition. This overview attempts to offer advice to all organizations engaged in small molecule screening based upon current best practices and theoretical considerations in library selection and acquisition.

  1. Small-molecule azomethines: organic photovoltaics via Schiff base condensation chemistry

    NARCIS (Netherlands)

    Petrus,M. L.; Bouwer, R. K. M.; Lafont, U.; Athanasopoulos, S.; Greenham, N. C.; Dingemans, T. J.


    Conjugated small-molecule azomethines for photovoltaic applications were prepared via Schiff base condensation chemistry. Bulk heterojunction (BHJ) devices exhibit efficiencies of 1.2% with MoOx as the hole-transporting layer. The versatility and simplicity of the chemistry is illustrated by prepari

  2. Comparative analyses of a small molecule/enzyme interaction by multiple users of Biacore technology

    NARCIS (Netherlands)

    Cannon, M.J.; Papalia, G.A.; Navratilova, I.; Fisher, R.J.; Roberts, L.R.; Worthy, K.M.; Stephen, A.G.; Marchesini, G.R.; Collins, E.J.; Casper, D.; Qiu, H.; Satpaev, D.; Liparoto, S.F.; Rice, D.A.; Gorshkova, I.; Darling, R.J.; Bennett, D.B.; Sekar, M.; Hommema, E.; Liang, A.M.; Day, E.S.; Inman, J.; Karlicek, S.H.; Ullrich, S.J.; Hodges, D.; Chu, T.; Sullivan, E.; Simpson, J.; Rafique, A.; Luginbühl, B.; Nyholm Westin, S.; Bynum, M.; Cachia, P.; Li, Y.J.; Kao, D.; Neurauter, A.; Wong, M.


    To gauge the experimental variability associated with Biacore analysis, 36 different investigators analyzed a small molecule/enzyme interaction under similar conditions. Acetazolamide (222 g/mol) binding to carbonic anhydrase II (CAII; 30,000 Da) was chosen as a model system. Both reagents were stab

  3. Small Molecule-Assisted Exfoliation of Layered Zirconium Phosphate Nanoplatelets by Ionic Liquids (United States)

    Xia, Fangqing; Yong, Huaisong; Han, Xiao; Sun, Dazhi


    Exfoliation of layered inorganic nanomaterials into single-layered sheets has been widely interested in materials chemistry and composite fabrication. Here, we report the exfoliation of layered zirconium phosphate nanoplatelets by using small molecule intercalating agents in ionic liquids, which opens a new platform for fabricating single-layered inorganic materials from synthetic layered compounds.


    DEFF Research Database (Denmark)

    Ruud, K.; Helgaker, T.; Jørgensen, Poul


    We report a systematic investigation of the magnetizability of a series of small molecules. The use of London atomic orbitals ensures gauge invariance and a fast basis set convergence. Good agreement is obtained with experimental magnetizabilities, both isotropic and anisotropic. The calculations...

  5. Small molecule inhibition of protein depalmitoylation as a new approach towards downregulation of oncogenic Ras signalling

    NARCIS (Netherlands)

    Dekker, Frank J.; Hedberg, Christian


    The H- and N-Ras GTPases are prominent examples of proteins, whose localizations and signalling capacities are regulated by reversible palmitoylations and depalmitoylations. Recently, the novel small molecule inhibitor palmostatin B has been described to inhibit Ras depalmitoylation and to revert th

  6. New serum markers for small-cell lung cancer. II. The neural cell adhesion molecule, NCAM

    DEFF Research Database (Denmark)

    Vangsted, A; Drivsholm, L; Andersen, E;


    The neural cell adhesion molecule (NCAM) was recently suggested as a marker for small-cell lung cancer (SCLC). Immunohistochemical analysis demonstrated the presence of the NCAM in 78% of SCLC patients and in 25% of patients with other cancer forms. NCAM was proposed to be the most sensitive marker...

  7. Diffusion nuclear magnetic resonance spectroscopy detects substoichiometric concentrations of small molecules in protein samples

    NARCIS (Netherlands)

    Ribeiro, João P.; Palczewska, Małgorzata; André, Sabine; Cañada, F. Javier; Gabius, Hans-Joachim; Jiménez-Barbero, Jesús; Mellström, Britt; Naranjo, José R.; Scheffers, Dirk-Jan; Groves, Patrick


    Small molecules are difficult to detect in protein solutions, whether they originate from elution during affinity chromatography (e.g., imidazole, lactose), buffer exchange (Tris), stabilizers (e.g., β-mercaptoethanol, glycerol), or excess labeling reagents (fluorescent reagents). Mass spectrometry

  8. A Small Molecule that Induces Intrinsic Pathway Apoptosis with Unparalleled Speed

    NARCIS (Netherlands)

    R. Palchaudhuri (Rahul); M.J. Lambrecht (Michael J.); R.C. Botham (Rachel C.); K.C. Partlow (Kathryn C.); T.J. vanHam (Tjakko J.); K.S. Putt (Karson S.); L.T. Nguyen (Laurie T.); S.-H. Kim (Seok-Ho); R.T. Peterson (Randall); T.M. Fan (Timothy M.); P.J. Hergenrother (Paul J.)


    textabstractApoptosis is generally believed to be a process thatrequires several hours, in contrast to non-programmed forms of cell death that can occur in minutes. Our findings challenge the time-consuming nature of apoptosis as we describe the discovery and characterization of a small molecule, na

  9. Small-molecule inhibition of APT1 affects Ras localization and signaling

    NARCIS (Netherlands)

    Dekker, Frank J.; Rocks, Oliver; Vartak, Nachiket; Menninger, Sascha; Hedberg, Christian; Balamurugan, Rengarajan; Wetzel, Stefan; Renner, Steffen; Gerauer, Marc; Schoelermann, Beate; Rusch, Marion; Kramer, John W.; Rauh, Daniel; Coates, Geoffrey W.; Brunsveld, Luc; Bastiaens, Philippe I. H.; Waldmann, Herbert


    Cycles of depalmitoylation and repalmitoylation critically control the steady-state localization and function of various peripheral membrane proteins, such as Ras proto-oncogene products. Interference with acylation using small molecules is a strategy to modulate cellular localization-and thereby un

  10. High-affinity small molecule-phospholipid complex formation: binding of siramesine to phosphatidicacid

    DEFF Research Database (Denmark)

    Khandelia, Himanshu


    , comparable to the affinities for the binding of small molecule ligands to proteins, was measured for phosphatidic acid (PA, mole fraction of XPA ) 0.2 in phosphatidylcholine vesicles), yielding a molecular partition coefficient of 240 ( 80 × 106. An MD simulation on the siramesine:PA interaction...

  11. Treatment of Prostate Cancer using Anti-androgen Small Molecules | NCI Technology Transfer Center | TTC (United States)

    The National Cancer Institute seeks parties interested in collaborative research to co-develop and commercialize a new class of small molecules for the treatment of prostate cancer. General information on co-development research collaborations, can be found on our web site (

  12. Rhodanine dye-based small molecule acceptors for organic photovoltaic cells. (United States)

    Kim, Yujeong; Song, Chang Eun; Moon, Sang-Jin; Lim, Eunhee


    The solution-processable small molecules based on carbazole or fluorene containing rhodanine dyes at both ends were synthesized and introduced as acceptors in organic photovoltaic cells. The high energy levels of their lowest unoccupied molecular orbitals resulted in a power conversion efficiency of 3.08% and an open circuit voltage of up to 1.03 V.

  13. OPLS3: A Force Field Providing Broad Coverage of Drug-like Small Molecules and Proteins. (United States)

    Harder, Edward; Damm, Wolfgang; Maple, Jon; Wu, Chuanjie; Reboul, Mark; Xiang, Jin Yu; Wang, Lingle; Lupyan, Dmitry; Dahlgren, Markus K; Knight, Jennifer L; Kaus, Joseph W; Cerutti, David S; Krilov, Goran; Jorgensen, William L; Abel, Robert; Friesner, Richard A


    The parametrization and validation of the OPLS3 force field for small molecules and proteins are reported. Enhancements with respect to the previous version (OPLS2.1) include the addition of off-atom charge sites to represent halogen bonding and aryl nitrogen lone pairs as well as a complete refit of peptide dihedral parameters to better model the native structure of proteins. To adequately cover medicinal chemical space, OPLS3 employs over an order of magnitude more reference data and associated parameter types relative to other commonly used small molecule force fields (e.g., MMFF and OPLS_2005). As a consequence, OPLS3 achieves a high level of accuracy across performance benchmarks that assess small molecule conformational propensities and solvation. The newly fitted peptide dihedrals lead to significant improvements in the representation of secondary structure elements in simulated peptides and native structure stability over a number of proteins. Together, the improvements made to both the small molecule and protein force field lead to a high level of accuracy in predicting protein-ligand binding measured over a wide range of targets and ligands (less than 1 kcal/mol RMS error) representing a 30% improvement over earlier variants of the OPLS force field.

  14. Following the nanostructural molecular orientation guidelines for sulfur versus thiophene units in small molecule photovoltaic cells. (United States)

    Kim, Yu Jin; Park, Chan Eon


    In bulk heterojunction (BHJ) organic photovoltaics, particularly those using small molecules, electron donor and/or electron acceptor materials form a distributed network in the photoactive layer where critical photo-physical processes occur. Extensive research has recently focused on the importance of sulfur atoms in the small molecules. Little is known about the three-dimensional orientation of these sulfur atom-containing molecules. Herein, we report on our research concerning the heterojunction textures of the crystalline molecular orientation of small compounds having sulfur-containing units in the side chains, specifically, compounds known as DR3TSBDT that contain the alkylthio group and DR3TBDTT that does not. The improved performance of the DR3TBDTT-based devices, particularly in the photocurrent and the fill factor, was attributed to the large population of donor compound crystallites with a favorable face-on orientation along the perpendicular direction. This orientation resulted in efficient charge transport and a reduction in charge recombination. These findings underscore the great potential of small-molecule solar cells and suggest that even higher efficiencies can be achieved through materials development and molecular orientation control.

  15. Yeast based small molecule screen for inhibitors of SARS-CoV.

    Directory of Open Access Journals (Sweden)

    Matthew Frieman

    Full Text Available Severe acute respiratory coronavirus (SARS-CoV emerged in 2002, resulting in roughly 8000 cases worldwide and 10% mortality. The animal reservoirs for SARS-CoV precursors still exist and the likelihood of future outbreaks in the human population is high. The SARS-CoV papain-like protease (PLP is an attractive target for pharmaceutical development because it is essential for virus replication and is conserved among human coronaviruses. A yeast-based assay was established for PLP activity that relies on the ability of PLP to induce a pronounced slow-growth phenotype when expressed in S. cerevisiae. Induction of the slow-growth phenotype was shown to take place over a 60-hour time course, providing the basis for conducting a screen for small molecules that restore growth by inhibiting the function of PLP. Five chemical suppressors of the slow-growth phenotype were identified from the 2000 member NIH Diversity Set library. One of these, NSC158362, potently inhibited SARS-CoV replication in cell culture without toxic effects on cells, and it specifically inhibited SARS-CoV replication but not influenza virus replication. The effect of NSC158362 on PLP protease, deubiquitinase and anti-interferon activities was investigated but the compound did not alter these activities. Another suppressor, NSC158011, demonstrated the ability to inhibit PLP protease activity in a cell-based assay. The identification of these inhibitors demonstrated a strong functional connection between the PLP-based yeast assay, the inhibitory compounds, and SARS-CoV biology. Furthermore the data with NSC158362 suggest a novel mechanism for inhibition of SARS-CoV replication that may involve an unknown activity of PLP, or alternatively a direct effect on a cellular target that modifies or bypasses PLP function in yeast and mammalian cells.

  16. Nox Inhibitors & Therapies: Rational Design of Peptidic and Small Molecule Inhibitors (United States)

    Cifuentes-Pagano, M. Eugenia; Meijles, Daniel N.; Pagano, Patrick J.


    Oxidative stress-related diseases underlie many if not all of the major leading causes of death in United States and the Western World. Thus, enormous interest from both academia and pharmaceutical industry has been placed on the development of agents which attenuate oxidative stress. With that in mind, great efforts have been placed in the development of inhibitors of NADPH oxidase (Nox), the major enzymatic source of reactive oxygen species and oxidative stress in many cells and tissue. The regulation of a catalytically active Nox enzyme involves numerous protein-protein interactions which, in turn, afford numerous targets for inhibition of its activity. In this review, we will provide an updated overview of the available Nox inhibitors, both peptidic and small molecules, and discuss the body of data related to their possible mechanisms of action and specificity towards each of the various isoforms of Nox. Indeed, there have been some very notable successes. However, despite great commitment by many in the field, the need for efficacious and well-characterized, isoform-specific Nox inhibitors, essential for the treatment of major diseases as well as for delineating the contribution of a given Nox in physiological redox signalling, continues to grow. PMID:26510437

  17. Cardioprotective Potentials of Plant-Derived Small Molecules against Doxorubicin Associated Cardiotoxicity

    Directory of Open Access Journals (Sweden)

    Shreesh Ojha


    Full Text Available Doxorubicin (DOX is a potent and widely used anthracycline antibiotic for the treatment of several malignancies. Unfortunately, the clinical utility of DOX is often restricted due to the elicitation of organ toxicity. Particularly, the increased risk for the development of dilated cardiomyopathy by DOX among the cancer survivors warrants major attention from the physicians as well as researchers to develop adjuvant agents to neutralize the noxious effects of DOX on the healthy myocardium. Despite these pitfalls, the use of traditional cytotoxic drugs continues to be the mainstay treatment for several types of cancer. Recently, phytochemicals have gained attention for their anticancer, chemopreventive, and cardioprotective activities. The ideal cardioprotective agents should not compromise the clinical efficacy of DOX and should be devoid of cumulative or irreversible toxicity on the naïve tissues. Furthermore, adjuvants possessing synergistic anticancer activity and quelling of chemoresistance would significantly enhance the clinical utility in combating DOX-induced cardiotoxicity. The present review renders an overview of cardioprotective effects of plant-derived small molecules and their purported mechanisms against DOX-induced cardiotoxicity. Phytochemicals serve as the reservoirs of pharmacophore which can be utilized as templates for developing safe and potential novel cardioprotective agents in combating DOX-induced cardiotoxicity.

  18. Structure-Based Drug Design of Small Molecule Peptide Deformylase Inhibitors to Treat Cancer

    Directory of Open Access Journals (Sweden)

    Jian Gao


    Full Text Available Human peptide deformylase (HsPDF is an important target for anticancer drug discovery. In view of the limited HsPDF, inhibitors were reported, and high-throughput virtual screening (HTVS studies based on HsPDF for developing new PDF inhibitors remain to be reported. We reported here on diverse small molecule inhibitors with excellent anticancer activities designed based on HTVS and molecular docking studies using the crystal structure of HsPDF. The compound M7594_0037 exhibited potent anticancer activities against HeLa, A549 and MCF-7 cell lines with IC50s of 35.26, 29.63 and 24.63 μM, respectively. Molecular docking studies suggested that M7594_0037 and its three derivatives could interact with HsPDF by several conserved hydrogen bonds. Moreover, the pharmacokinetic and toxicity properties of M7594_0037 and its derivatives were predicted using the OSIRIS property explorer. Thus, M7594_0037 and its derivatives might represent a promising scaffold for the further development of novel anticancer drugs.

  19. The p53-reactivating small molecule RITA induces senescence in head and neck cancer cells.

    Directory of Open Access Journals (Sweden)

    Hui-Ching Chuang

    Full Text Available TP53 is the most commonly mutated gene in head and neck cancer (HNSCC, with mutations being associated with resistance to conventional therapy. Restoring normal p53 function has previously been investigated via the use of RITA (reactivation of p53 and induction of tumor cell apoptosis, a small molecule that induces a conformational change in p53, leading to activation of its downstream targets. In the current study we found that RITA indeed exerts significant effects in HNSCC cells. However, in this model, we found that a significant outcome of RITA treatment was accelerated senescence. RITA-induced senescence in a variety of p53 backgrounds, including p53 null cells. Also, inhibition of p53 expression did not appear to significantly inhibit RITA-induced senescence. Thus, this phenomenon appears to be partially p53-independent. Additionally, RITA-induced senescence appears to be partially mediated by activation of the DNA damage response and SIRT1 (Silent information regulator T1 inhibition, with a synergistic effect seen by combining either ionizing radiation or SIRT1 inhibition with RITA treatment. These data point toward a novel mechanism of RITA function as well as hint to its possible therapeutic benefit in HNSCC.

  20. Small Molecule Agonists for the Type I Interferon Receptor: An In Silico Approach. (United States)

    Wei, Lianhu; Bello, Angelica M; Majchrzak-Kita, Beata; Salum, Noruê; Lewis, Melissa M; Kotra, Lakshmi P; Fish, Eleanor N


    Type I interferons (IFNs) exhibit broad-spectrum antiviral activity, with potential utility against emerging acute virus infections that pose a threat to global health. Recombinant IFN-αs that have been approved for clinical use require cold storage and are administered through intramuscular or subcutaneous injection, features that are problematic for global distribution, storage, and administration. Cognizant that the biological potency of an IFN-α subtype is determined by its binding affinity to the type I IFN receptor, IFNAR, we identified a panel of small molecule nonpeptide compounds using an in silico screening strategy that incorporated specific structural features of amino acids in the receptor-binding domains of the most potent IFN-α, IFN alfacon-1. Hit compounds were selected based on ease of synthesis and formulation properties. In preliminary biological assays, we provide evidence that these compounds exhibit antiviral activity. This proof-of-concept study validates the strategy of in silico design and development for IFN mimetics.

  1. New small-molecule inhibitors of dihydrofolate reductase inhibit Streptococcus mutans. (United States)

    Zhang, Qiong; Nguyen, Thao; McMichael, Megan; Velu, Sadanandan E; Zou, Jing; Zhou, Xuedong; Wu, Hui


    Streptococcus mutans is a major aetiological agent of dental caries. Formation of biofilms is a key virulence factor of S. mutans. Drugs that inhibit S. mutans biofilms may have therapeutic potential. Dihydrofolate reductase (DHFR) plays a critical role in regulating the metabolism of folate. DHFR inhibitors are thus potent drugs and have been explored as anticancer and antimicrobial agents. In this study, a library of analogues based on a DHFR inhibitor, trimetrexate (TMQ), an FDA-approved drug, was screened and three new analogues that selectively inhibited S. mutans were identified. The most potent inhibitor had a 50% inhibitory concentration (IC50) of 454.0±10.2nM for the biofilm and 8.7±1.9nM for DHFR of S. mutans. In contrast, the IC50 of this compound for human DHFR was ca. 1000nM, a >100-fold decrease in its potency, demonstrating the high selectivity of the analogue. An analogue that exhibited the least potency for the S. mutans biofilm also had the lowest activity towards inhibiting S. mutans DHFR, further indicating that inhibition of biofilms is related to reduced DHFR activity. These data, along with docking of the most potent analogue to the modelled DHFR structure, suggested that the TMQ analogues indeed selectively inhibited S. mutans through targeting DHFR. These potent and selective small molecules are thus promising lead compounds to develop new effective therapeutics to prevent and treat dental caries.

  2. In Search of Small Molecule Inhibitors Targeting the Flexible CK2 Subunit Interface

    Directory of Open Access Journals (Sweden)

    Benoît Bestgen


    Full Text Available Protein kinase CK2 is a tetrameric holoenzyme composed of two catalytic (α and/or α’ subunits and two regulatory (β subunits. Crystallographic data paired with fluorescence imaging techniques have suggested that the formation of the CK2 holoenzyme complex within cells is a dynamic process. Although the monomeric CK2α subunit is endowed with a constitutive catalytic activity, many of the plethora of CK2 substrates are exclusively phosphorylated by the CK2 holoenzyme. This means that the spatial and high affinity interaction between CK2α and CK2β subunits is critically important and that its disruption may provide a powerful and selective way to block the phosphorylation of substrates requiring the presence of CK2β. In search of compounds inhibiting this critical protein–protein interaction, we previously designed an active cyclic peptide (Pc derived from the CK2β carboxy-terminal domain that can efficiently antagonize the CK2 subunit interaction. To understand the functional significance of this interaction, we generated cell-permeable versions of Pc, exploring its molecular mechanisms of action and the perturbations of the signaling pathways that it induces in intact cells. The identification of small molecules inhibitors of this critical interaction may represent the first-choice approach to manipulate CK2 in an unconventional way.

  3. The Small Molecule DAM Inhibitor, Pyrimidinedione, Disrupts Streptococcus pneumoniae Biofilm Growth In Vitro. (United States)

    Yadav, Mukesh Kumar; Go, Yoon Young; Chae, Sung-Won; Song, Jae-Jun


    Streptococcus pneumoniae persist in the human nasopharynx within organized biofilms. However, expansion to other tissues may cause severe infections such as pneumonia, otitis media, bacteremia, and meningitis, especially in children and the elderly. Bacteria within biofilms possess increased tolerance to antibiotics and are able to resist host defense systems. Bacteria within biofilms exhibit different physiology, metabolism, and gene expression profiles than planktonic cells. These differences underscore the need to identify alternative therapeutic targets and novel antimicrobial compounds that are effective against pneumococcal biofilms. In bacteria, DNA adenine methyltransferase (Dam) alters pathogenic gene expression and catalyzes the methylation of adenine in the DNA duplex and of macromolecules during the activated methyl cycle (AMC). In pneumococci, AMC is involved in the biosynthesis of quorum sensing molecules that regulate competence and biofilm formation. In this study, we examine the effect of a small molecule Dam inhibitor, pyrimidinedione, on Streptococcus pneumoniae biofilm formation and evaluate the changes in global gene expression within biofilms via microarray analysis. The effects of pyrimidinedione on in vitro biofilms were studied using a static microtiter plate assay, and the architecture of the biofilms was viewed using confocal and scanning electron microscopy. The cytotoxicity of pyrimidinedione was tested on a human middle ear epithelium cell line by CCK-8. In situ oligonucleotide microarray was used to compare the global gene expression of Streptococcus pneumoniae D39 within biofilms grown in the presence and absence of pyrimidinedione. Real-time RT-PCR was used to study gene expression. Pyrimidinedione inhibits pneumococcal biofilm growth in vitro in a concentration-dependent manner, but it does not inhibit planktonic cell growth. Confocal microscopy analysis revealed the absence of organized biofilms, where cell-clumps were scattered

  4. The Small Molecule DAM Inhibitor, Pyrimidinedione, Disrupts Streptococcus pneumoniae Biofilm Growth In Vitro.

    Directory of Open Access Journals (Sweden)

    Mukesh Kumar Yadav

    Full Text Available Streptococcus pneumoniae persist in the human nasopharynx within organized biofilms. However, expansion to other tissues may cause severe infections such as pneumonia, otitis media, bacteremia, and meningitis, especially in children and the elderly. Bacteria within biofilms possess increased tolerance to antibiotics and are able to resist host defense systems. Bacteria within biofilms exhibit different physiology, metabolism, and gene expression profiles than planktonic cells. These differences underscore the need to identify alternative therapeutic targets and novel antimicrobial compounds that are effective against pneumococcal biofilms. In bacteria, DNA adenine methyltransferase (Dam alters pathogenic gene expression and catalyzes the methylation of adenine in the DNA duplex and of macromolecules during the activated methyl cycle (AMC. In pneumococci, AMC is involved in the biosynthesis of quorum sensing molecules that regulate competence and biofilm formation. In this study, we examine the effect of a small molecule Dam inhibitor, pyrimidinedione, on Streptococcus pneumoniae biofilm formation and evaluate the changes in global gene expression within biofilms via microarray analysis. The effects of pyrimidinedione on in vitro biofilms were studied using a static microtiter plate assay, and the architecture of the biofilms was viewed using confocal and scanning electron microscopy. The cytotoxicity of pyrimidinedione was tested on a human middle ear epithelium cell line by CCK-8. In situ oligonucleotide microarray was used to compare the global gene expression of Streptococcus pneumoniae D39 within biofilms grown in the presence and absence of pyrimidinedione. Real-time RT-PCR was used to study gene expression. Pyrimidinedione inhibits pneumococcal biofilm growth in vitro in a concentration-dependent manner, but it does not inhibit planktonic cell growth. Confocal microscopy analysis revealed the absence of organized biofilms, where cell

  5. Targeting of the MYCN protein with small molecule c-MYC inhibitors.

    Directory of Open Access Journals (Sweden)

    Inga Müller

    Full Text Available Members of the MYC family are the most frequently deregulated oncogenes in human cancer and are often correlated with aggressive disease and/or poorly differentiated tumors. Since patients with MYCN-amplified neuroblastoma have a poor prognosis, targeting MYCN using small molecule inhibitors could represent a promising therapeutic approach. We have previously demonstrated that the small molecule 10058-F4, known to bind to the c-MYC bHLHZip dimerization domain and inhibiting the c-MYC/MAX interaction, also interferes with the MYCN/MAX dimerization in vitro and imparts anti-tumorigenic effects in neuroblastoma tumor models with MYCN overexpression. Our previous work also revealed that MYCN-inhibition leads to mitochondrial dysfunction resulting in accumulation of lipid droplets in neuroblastoma cells. To expand our understanding of how small molecules interfere with MYCN, we have now analyzed the direct binding of 10058-F4, as well as three of its analogs; #474, #764 and 10058-F4(7RH, one metabolite C-m/z 232, and a structurally unrelated c-MYC inhibitor 10074-G5, to the bHLHZip domain of MYCN. We also assessed their ability to induce apoptosis, neurite outgrowth and lipid accumulation in neuroblastoma cells. Interestingly, all c-MYC binding molecules tested also bind MYCN as assayed by surface plasmon resonance. Using a proximity ligation assay, we found reduced interaction between MYCN and MAX after treatment with all molecules except for the 10058-F4 metabolite C-m/z 232 and the non-binder 10058-F4(7RH. Importantly, 10074-G5 and 10058-F4 were the most efficient in inducing neuronal differentiation and lipid accumulation in MYCN-amplified neuroblastoma cells. Together our data demonstrate MYCN-binding properties for a selection of small molecules, and provide functional information that could be of importance for future development of targeted therapies against MYCN-amplified neuroblastoma.

  6. Environmental Education and Small Business Environmental Activity (United States)

    Redmond, Janice; Walker, Beth


    Environmental education is seen as a key driver of small business environmental management, yet little is known about the activities small business owner-managers are undertaking to reduce their environmental impact or in what areas they may need education. Therefore, research that can identify environmental management activities being undertaken…

  7. Discovery and Optimization of Small Molecule Splicing Modifiers of Survival Motor Neuron 2 as a Treatment for Spinal Muscular Atrophy. (United States)

    Woll, Matthew G; Qi, Hongyan; Turpoff, Anthony; Zhang, Nanjing; Zhang, Xiaoyan; Chen, Guangming; Li, Chunshi; Huang, Song; Yang, Tianle; Moon, Young-Choon; Lee, Chang-Sun; Choi, Soongyu; Almstead, Neil G; Naryshkin, Nikolai A; Dakka, Amal; Narasimhan, Jana; Gabbeta, Vijayalakshmi; Welch, Ellen; Zhao, Xin; Risher, Nicole; Sheedy, Josephine; Weetall, Marla; Karp, Gary M


    The underlying cause of spinal muscular atrophy (SMA) is a deficiency of the survival motor neuron (SMN) protein. Starting from hits identified in a high-throughput screening campaign and through structure-activity relationship investigations, we have developed small molecules that potently shift the alternative splicing of the SMN2 exon 7, resulting in increased production of the full-length SMN mRNA and protein. Three novel chemical series, represented by compounds 9, 14, and 20, have been optimized to increase the level of SMN protein by >50% in SMA patient-derived fibroblasts at concentrations of <160 nM. Daily administration of these compounds to severe SMA Δ7 mice results in an increased production of SMN protein in disease-relevant tissues and a significant increase in median survival time in a dose-dependent manner. Our work supports the development of an orally administered small molecule for the treatment of patients with SMA.

  8. Detection of small molecules by an evanescent wave fiber optic biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Shriver-Lake, L.C.; Ligler, F.S. [Naval Research Lab., Washington, DC (United States). Center for Bio/Molecular Science and Engineering


    Detection of small molecules is important in environmental analyses as most pollutants are low molecular weight compounds. Utilizing the specificity of antibodies, the rapid signal transduction of optical fibers and the signal-to-noise discrimination of fluorescence, an evanescent wave fiber optic-based biosensor was modified for the detection of these molecules. To facilitate the isolation of personnel and equipment from hazardous environments, long partially clad optical fibers are employed. Antibodies were immobilized on the 10 cm sensing region at the distal portion of the optical fiber probe. A 200 {micro}l sample chamber was fabricated from a capillary tube. The core of the fiber in the sensing region is tapered for maximum signal recovery. A competitive immunoassay was performed. Basically, the small molecule competes with a fluorescently-labelled analog for the capture antibody binding sites. As the level of analyte increases in the sample, the fluorescent signal decreases. Two assays for the small molecules, trinitrotoluene (TNT) and polychlorinated biphenyl (PCB) will be described. Detection levels of 10 ng/ml TNT (8 ppb) have been achieved with this sensor.

  9. Structure elucidation of uniformly 13C labeled small molecule natural products. (United States)

    Reibarkh, Mikhail; Wyche, Thomas P; Saurí, Josep; Bugni, Tim S; Martin, Gary E; Williamson, R Thomas


    Utilization of isotopically labeled proteins and peptides is a routinely employed approach in biomolecular NMR investigations. The widespread availability of inexpensive, uniformly (13) C-enriched glucose now makes it possible to produce uniformly (13) C-labeled natural products by microbial fermentation. In this feature article, the authors describe an experimental approach for the rapid structural characterization of uniformly (13) C-labeled natural products based on the Constant-Time HSQC (CT-HSQC) experiment. Rigorous theoretical evaluation of the CT-HSQC experiment allowed the applicability of the experiment to be expanded from the traditional, narrow scope of labeled amino acids to encompass virtually any small molecule or U-(13) C labeled natural product. A suite of experiments including CT-HSQC, (13) C-(13) C COSY, and COSYLR experiments is sufficient for the structure elucidation of uniformly (13) C-labeled small molecules and natural products. Differences in NMR approaches for structure elucidation of natural abundance and uniformly (13) C-labeled molecules are also discussed. The present work provides a researcher working in this area of natural products chemistry with NMR structure elucidation tools for investigating (13) C-labeled small molecules and natural products.

  10. Prediction of adsorption of small molecules in porous materials based on ab initio force field method

    Institute of Scientific and Technical Information of China (English)


    Computational prediction of adsorption of small molecules in porous materials has great impact on the basic and applied research in chemical engineering and material sciences. In this work,we report an approach based on grand canonical ensemble Monte Carlo(GCMC) simulations and ab initio force fields. We calculated the adsorption curves of ammonia in ZSM-5 zeolite and hydrogen in MOF-5(a metal-organic-framework material). The predictions agree well with experimental data. Because the predictions are based on the first principle force fields,this approach can be used for the adsorption prediction of new molecules or materials without experimental data as guidance.

  11. A quantitative application of the J-based configuration analysis method to a flexible small molecule. (United States)

    Sharman, Gary J


    An example of the use of the J-based configuration analysis method to determine relative stereochemistry of a small molecule related to reboxetine is described. This study was complicated by the fact that the molecule did not exhibit J-couplings and NOEs consistent with a single conformation, but rather an ensemble average. A quantitative fitting procedure using predicted couplings and NOEs from all possible conformers was used. This gave a clear indication of the stereochemistry, and the populations of the conformers involved.

  12. SLAP: Small Labeling Pair for Single-Molecule Super-Resolution Imaging. (United States)

    Wieneke, Ralph; Raulf, Anika; Kollmannsperger, Alina; Heilemann, Mike; Tampé, Robert


    Protein labeling with synthetic fluorescent probes is a key technology in chemical biology and biomedical research. A sensitive and efficient modular labeling approach (SLAP) was developed on the basis of a synthetic small-molecule recognition unit (Ni-trisNTA) and the genetically encoded minimal protein His6-10 -tag. High-density protein tracing by SLAP was demonstrated. This technique allows super-resolution fluorescence imaging and fulfills the necessary sampling criteria for single-molecule localization-based imaging techniques. It avoids masking by large probes, for example, antibodies, and supplies sensitive, precise, and robust size analysis of protein clusters (nanodomains).

  13. A small molecule glycosaminoglycan mimetic blocks Plasmodium invasion of the mosquito midgut.

    Directory of Open Access Journals (Sweden)

    Derrick K Mathias

    Full Text Available Malaria transmission-blocking (T-B interventions are essential for malaria elimination. Small molecules that inhibit the Plasmodium ookinete-to-oocyst transition in the midgut of Anopheles mosquitoes, thereby blocking sporogony, represent one approach to achieving this goal. Chondroitin sulfate glycosaminoglycans (CS-GAGs on the Anopheles gambiae midgut surface are putative ligands for Plasmodium falciparum ookinetes. We hypothesized that our synthetic polysulfonated polymer, VS1, acting as a decoy molecular mimetic of midgut CS-GAGs confers malaria T-B activity. In our study, VS1 repeatedly reduced midgut oocyst development by as much as 99% (P<0.0001 in mosquitoes fed with P. falciparum and Plasmodium berghei. Through direct-binding assays, we observed that VS1 bound to two critical ookinete micronemal proteins, each containing at least one von Willebrand factor A (vWA domain: (i circumsporozoite protein and thrombospondin-related anonymous protein-related protein (CTRP and (ii vWA domain-related protein (WARP. By immunofluorescence microscopy, we observed that VS1 stains permeabilized P. falciparum and P. berghei ookinetes but does not stain P. berghei CTRP knockouts or transgenic parasites lacking the vWA domains of CTRP while retaining the thrombospondin repeat region. We produced structural homology models of the first vWA domain of CTRP and identified, as expected, putative GAG-binding sites on CTRP that align closely with those predicted for the human vWA A1 domain and the Toxoplasma gondii MIC2 adhesin. Importantly, the models also identified patches of electropositive residues that may extend CTRP's GAG-binding motif and thus potentiate VS1 binding. Our molecule binds to a critical, conserved ookinete protein, CTRP, and exhibits potent malaria T-B activity. This study lays the framework for a high-throughput screen of existing libraries of safe compounds to identify those with potent T-B activity. We envision that such compounds when

  14. Sequence-Specific Biosensing of DNA Target through Relay PCR with Small-Molecule Fluorophore. (United States)

    Yasmeen, Afshan; Du, Feng; Zhao, Yongyun; Dong, Juan; Chen, Haodong; Huang, Xin; Cui, Xin; Tang, Zhuo


    Polymerase chain reaction coupled with signal generation offers sensitive recognition of target DNA sequence; however, these procedures require fluorophore-labeled oligonucleotide probes and high-tech equipment to achieve high specificity. Therefore, intensive research has been conducted to develop reliable, convenient, and economical DNA detection methods. The relay PCR described here is the first sequence-specific detection method using a small-molecule fluorophore as a sensor and combines the classic 5'-3' exonuclease activity of Taq polymerase with an RNA mimic of GFP to build a label-free DNA detection platform. Primarily, Taq polymerase cleaves the 5' noncomplementary overhang of the target specific probe during extension of the leading primer to release a relay oligo to initiate tandem PCR of the reporting template, which encodes the sequence of RNA aptamer. Afterward, the PCR product is transcribed to mRNA, which could generate a fluorescent signal in the presence of corresponding fluorophore. In addition to high sensitivity and specificity, the flexibility of choosing different fluorescent reporting signals makes this method versatile in either single or multiple target detection.

  15. A small molecule inhibitor of PAI-1 protects against doxorubicin-induced cellular senescence. (United States)

    Ghosh, Asish K; Rai, Rahul; Park, Kitae E; Eren, Mesut; Miyata, Toshio; Wilsbacher, Lisa D; Vaughan, Douglas E


    Doxorubicin, an anthracycline antibiotic, is a commonly used anticancer drug. In spite of its widespread usage, its therapeutic effect is limited by its cardiotoxicity. On the cellular level, Doxorubicin-induced cardiotoxicity manifests as stress induced premature senescence. Previously, we demonstrated that plasminogen activator inhibitor-1 (PAI-1), a potent inhibitor of serine proteases, is an important biomarker and regulator of cellular senescence and aging. Here, we tested the hypothesis that pharmacological inhibition of cellular PAI-1 protects against stress- and aging-induced cellular senescence and delineated the molecular basis of protective action of PAI-1 inhibition. Results show that TM5441, a potent small molecule inhibitor of PAI-1, effectively prevents Doxorubicin-induced senescence in cardiomyocytes, fibroblasts and endothelial cells. TM5441 exerts its inhibitory effect on Doxorubicin-induced cellular senescence by decreasing reactive oxygen species generation, induction of antioxidants like catalase and suppression of stress-induced senescence cadre p53, p21, p16, PAI-1 and IGFBP3. Importantly, TM5441 also reduces replicative senescence of fibroblasts. Together these results for the first time demonstrate the efficacy of PAI-1 inhibitor in prevention of Doxorubicin-induced and replicative senescence in normal cells. Thus PAI-1 inhibitor may form an important adjuvant component of chemotherapy regimens, limiting not only Doxorubicin-induced cardiac senescence but also ameliorating the prothrombotic profile.

  16. Roadmap to cellular reprogramming--manipulating transcriptional networks with DNA, RNA, proteins and small molecules. (United States)

    Wörsdörfer, P; Thier, M; Kadari, A; Edenhofer, F


    Recent reports demonstrate that the plasticity of mammalian somatic cells is much higher than previously assumed and that ectopic expression of transcription factors may have the potential to induce the conversion of any cell type into another. Fibroblast cells can be converted into embryonic stem cell-like cells, neural cells, cardiomyocytes, macrophage-like cells as well as blood progenitors. Additionally, the conversion of astrocytes into neurons or neural stem cells into monocytes has been demonstrated. Nowadays, in the era of systems biology, continuously growing holistic data sets are providing increasing insights into core transcriptional networks and cellular signaling pathways. This knowledge enables cell biologists to understand how cellular fate is determined and how it could be manipulated. As a consequence for biomedical applications, it might be soon possible to convert patient specific somatic cells directly into desired transplantable other cell types. The clinical value, however, of such reprogrammed cells is currently limited due to the invasiveness of methods applied to induce reprogramming factor activity. This review will focus on experimental strategies to ectopically induce cell fate modulators. We will emphasize those strategies that enable efficient and robust overexpression of transcription factors by minimal genetic alterations of the host genome. Furthermore, we will discuss procedures devoid of any genomic manipulation, such as the direct delivery of mRNA, proteins, or the use of small molecules. By this, we aim to give a comprehensive overview on state of the art techniques that harbor the potential to generate safe reprogrammed cells for clinical applications.

  17. Targeting DDX3 with a small molecule inhibitor for lung cancer therapy. (United States)

    Bol, Guus M; Vesuna, Farhad; Xie, Min; Zeng, Jing; Aziz, Khaled; Gandhi, Nishant; Levine, Anne; Irving, Ashley; Korz, Dorian; Tantravedi, Saritha; Heerma van Voss, Marise R; Gabrielson, Kathleen; Bordt, Evan A; Polster, Brian M; Cope, Leslie; van der Groep, Petra; Kondaskar, Atul; Rudek, Michelle A; Hosmane, Ramachandra S; van der Wall, Elsken; van Diest, Paul J; Tran, Phuoc T; Raman, Venu


    Lung cancer is the most common malignancy worldwide and is a focus for developing targeted therapies due to its refractory nature to current treatment. We identified a RNA helicase, DDX3, which is overexpressed in many cancer types including lung cancer and is associated with lower survival in lung cancer patients. We designed a first-in-class small molecule inhibitor, RK-33, which binds to DDX3 and abrogates its activity. Inhibition of DDX3 by RK-33 caused G1 cell cycle arrest, induced apoptosis, and promoted radiation sensitization in DDX3-overexpressing cells. Importantly, RK-33 in combination with radiation induced tumor regression in multiple mouse models of lung cancer. Mechanistically, loss of DDX3 function either by shRNA or by RK-33 impaired Wnt signaling through disruption of the DDX3-β-catenin axis and inhibited non-homologous end joining-the major DNA repair pathway in mammalian somatic cells. Overall, inhibition of DDX3 by RK-33 promotes tumor regression, thus providing a compelling argument to develop DDX3 inhibitors for lung cancer therapy.

  18. Small molecule inhibitors of PCNA/PIP-box interaction suppress translesion DNA synthesis. (United States)

    Actis, Marcelo; Inoue, Akira; Evison, Benjamin; Perry, Scott; Punchihewa, Chandanamali; Fujii, Naoaki


    Proliferating cell nuclear antigen (PCNA) is an essential component for DNA replication and DNA damage response. Numerous proteins interact with PCNA through their short sequence called the PIP-box to be promoted to their respective functions. PCNA supports translesion DNA synthesis (TLS) by interacting with TLS polymerases through PIP-box interaction. Previously, we found a novel small molecule inhibitor of the PCNA/PIP-box interaction, T2AA, which inhibits DNA replication in cells. In this study, we created T2AA analogues and characterized them extensively for TLS inhibition. Compounds that inhibited biochemical PCNA/PIP-box interaction at an IC50 <5 μM inhibited cellular DNA replication at 10 μM as measured by BrdU incorporation. In cells lacking nucleotide-excision repair activity, PCNA inhibitors inhibited reactivation of a reporter plasmid that was globally damaged by cisplatin, suggesting that the inhibitors blocked the TLS that allows replication of the plasmid. PCNA inhibitors increased γH2AX induction and cell viability reduction mediated by cisplatin. Taken together, these findings suggest that inhibitors of PCNA/PIP-box interaction could chemosensitize cells to cisplatin by inhibiting TLS.

  19. Small-Molecule XIAP Inhibitors Enhance γ-Irradiation-Induced Apoptosis in Glioblastoma

    Directory of Open Access Journals (Sweden)

    Sri Hari Krishna Vellanki


    Full Text Available Because evasion of apoptosis can cause radioresistance of glioblastoma, there is a need to design rational strategies that counter apoptosis resistance. In the present study, we investigated the potential of targeting the antiapoptotic protein XIAP for the radiosensitization of glioblastoma. Here, we report that small-molecule XIAP inhibitors significantly enhance γ-irradiation-induced loss of viability and apoptosis and cooperate with γ-irradiation to suppress clonogenic survival of glioblastoma cells. Analysis of molecular mechanisms reveals that XIAP inhibitors act in concert with γ-irradiation to cause mitochondrial outer membrane permeabilization, caspase activation, and caspasedependent apoptosis. Importantly, XIAP inhibitors also sensitize primary cultured glioblastoma cells derived from surgical specimens as well as glioblastoma-initiating stemlike cancer stem cells for γ-irradiation. In contrast, they do not increase the toxicity of γ-irradiation on some nonmalignant cells of the central nervous system, including rat neurons or glial cells, pointing to some tumor selectivity. In conclusion, by demonstrating for the first time that smallmolecule XIAP inhibitors increase the radiosensitivity of glioblastoma cells while sparing normal cells of the central nervous system, our findings build the rationale for further (preclinical development of XIAP inhibitors in combination with γ-irradiation in glioblastoma.

  20. Promoting in vivo remyelination with small molecules: a neuroreparative pharmacological treatment for Multiple Sclerosis (United States)

    Medina-Rodríguez, Eva María; Bribián, Ana; Boyd, Amanda; Palomo, Valle; Pastor, Jesús; Lagares, Alfonso; Gil, Carmen; Martínez, Ana; Williams, Anna; de Castro, Fernando


    Multiple Sclerosis (MS) is a neurodegenerative disease where immune-driven demyelination occurs with inefficient remyelination, but therapies are limited, especially those to enhance repair. Here, we show that the dual phosphodiesterase (PDE)7- glycogen synthase kinase (GSK)3 inhibitor, VP3.15, a heterocyclic small molecule with good pharmacokinetic properties and safety profile, improves in vivo remyelination in mouse and increases both adult mouse and adult human oligodendrocyte progenitor cell (OPC) differentiation, in addition to its immune regulatory action. The dual inhibition is synergistic, as increasing intracellular levels of cAMP by cyclic nucleotide PDE inhibition both suppresses the immune response and increases remyelination, and in addition, inhibition of GSK3 limits experimental autoimmune encephalomyelitis in mice. This combination of an advantageous effect on the immune response and an enhancement of repair, plus demonstration of its activity on adult human OPCs, leads us to propose dual PDE7-GSK3 inhibition, and specifically VP3.15, as a neuroprotective and neuroreparative disease-modifying treatment for MS. PMID:28256546

  1. Targeting the OB-Folds of Replication Protein A with Small Molecules

    Directory of Open Access Journals (Sweden)

    Victor J. Anciano Granadillo


    Full Text Available Replication protein A (RPA is the main eukaryotic single-strand (ss DNA-binding protein involved in DNA replication and repair. We have identified and developed two classes of small molecule inhibitors (SMIs that show in vitro inhibition of the RPA-DNA interaction. We present further characterization of these SMIs with respect to their target binding, mechanism of action, and specificity. Both reversible and irreversible modes of inhibition are observed for the different classes of SMIs with one class found to specifically interact with DNA-binding domains A and B (DBD-A/B of RPA. In comparison with other oligonucleotide/oligosaccharide binding-fold (OB-fold containing ssDNA-binding proteins, one class of SMIs displayed specificity for the RPA protein. Together these data demonstrate that the specific targeting of a protein-DNA interaction can be exploited towards interrogating the cellular activity of RPA as well as increasing the efficacy of DNA-damaging chemotherapeutics used in cancer treatment.

  2. Targeting the OB-Folds of Replication Protein A with Small Molecules (United States)

    Anciano Granadillo, Victor J.; Earley, Jennifer N.; Shuck, Sarah C.; Georgiadis, Millie M.; Fitch, Richard W.; Turchi, John J.


    Replication protein A (RPA) is the main eukaryotic single-strand (ss) DNA-binding protein involved in DNA replication and repair. We have identified and developed two classes of small molecule inhibitors (SMIs) that show in vitro inhibition of the RPA-DNA interaction. We present further characterization of these SMIs with respect to their target binding, mechanism of action, and specificity. Both reversible and irreversible modes of inhibition are observed for the different classes of SMIs with one class found to specifically interact with DNA-binding domains A and B (DBD-A/B) of RPA. In comparison with other oligonucleotide/oligosaccharide binding-fold (OB-fold) containing ssDNA-binding proteins, one class of SMIs displayed specificity for the RPA protein. Together these data demonstrate that the specific targeting of a protein-DNA interaction can be exploited towards interrogating the cellular activity of RPA as well as increasing the efficacy of DNA-damaging chemotherapeutics used in cancer treatment. PMID:21188165

  3. Small Molecule Membrane Transporters in the Mammalian Podocyte: A Pathogenic and Therapeutic Target

    Directory of Open Access Journals (Sweden)

    Cristina Zennaro


    Full Text Available The intriguingly complex glomerular podocyte has been a recent object of intense study. Researchers have sought to understand its role in the pathogenesis of common proteinuric diseases such as minimal change disease and focal segmental glomerular sclerosis. In particular, considerable effort has been directed towards the anatomic and functional barrier to macromolecular filtration provided by the secondary foot processes, but little attention has been paid to the potential of podocytes to handle plasma proteins beyond the specialization of the slit diaphragm. Renal membrane transporters in the proximal tubule have been extensively studied for decades, particularly in relation to drug metabolism and elimination. Recently, uptake and efflux transporters for small organic molecules have also been found in the glomerular podocyte, and we and others have found that these transporters can engage not only common pharmaceuticals but also injurious endogenous and exogenous agents. We have also found that the activity of podocyte transporters can be manipulated to inhibit pathogen uptake and efflux. It is conceivable that podocyte transporters may play a role in disease pathogenesis and may be a target for future drug development.

  4. From the Gla domain to a novel small-molecule detector of apoptosis

    Institute of Scientific and Technical Information of China (English)

    Avi Cohen; Anat Shirvan; Galit Levin; Hagit Grimberg; Ayelet Reshef; Ilan Ziv


    Apoptosis plays a pivotal role in the etiology or pathogenesis of numerous medical disorders, and thus, target-ing of apoptotic cells may substantially advance patient care. In our quest for novel low-molecular-weight probes for apoptosis, we focused on the uncommon amino acid γ-carboxyglutamic acid (Gla), which plays a vital role in the binding of clotting factors to negatively charged phosphofipid surfaces. Based on the aikyl-malonic acid motif of Gia, we have developed and now present ML-10 (2-(5-fluoro-pentyl)-2-methyl-malonic acid, MW=206 Da), the pro-totypical member of a novel family of small-molecule detectors of apoptosis. ML-10 was found to perform selective uptake and accumulation in apoptotic cells, while being excluded from either viable or necrotic cells. ML-10 uptake correlates with the apoptotic hallmarks of caspase activation, Annexin-V binding and disruption of mitochondrial membrane potential. The malonate moiety was found to be crucial for ML-10 function in apoptosis detection. ML-10 responds to a unique complex of features of the cell in early apoptosis, comprising irreversible loss of membrane potential, permanent acidification of cell membrane and cytoplasm, and preservation of membrane integrity. ML-10 is therefore the most compact apoptosis probe known to date. Due to its fluorine atom, ML-10 is amenable to radio-labeling with the 18SF isotope, towards its potential future use for clinical positron emission tomography imaging of apoptosis.

  5. Small-molecule auxin inhibitors that target YUCCA are powerful tools for studying auxin function. (United States)

    Kakei, Yusuke; Yamazaki, Chiaki; Suzuki, Masashi; Nakamura, Ayako; Sato, Akiko; Ishida, Yosuke; Kikuchi, Rie; Higashi, Shouichi; Kokudo, Yumiko; Ishii, Takahiro; Soeno, Kazuo; Shimada, Yukihisa


    Auxin is essential for plant growth and development, this makes it difficult to study the biological function of auxin using auxin-deficient mutants. Chemical genetics have the potential to overcome this difficulty by temporally reducing the auxin function using inhibitors. Recently, the indole-3-pyruvate (IPyA) pathway was suggested to be a major biosynthesis pathway in Arabidopsis thaliana L. for indole-3-acetic acid (IAA), the most common member of the auxin family. In this pathway, YUCCA, a flavin-containing monooxygenase (YUC), catalyzes the last step of conversion from IPyA to IAA. In this study, we screened effective inhibitors, 4-biphenylboronic acid (BBo) and 4-phenoxyphenylboronic acid (PPBo), which target YUC. These compounds inhibited the activity of recombinant YUC in vitro, reduced endogenous IAA content, and inhibited primary root elongation and lateral root formation in wild-type Arabidopsis seedlings. Co-treatment with IAA reduced the inhibitory effects. Kinetic studies of BBo and PPBo showed that they are competitive inhibitors of the substrate IPyA. Inhibition constants (Ki ) of BBo and PPBo were 67 and 56 nm, respectively. In addition, PPBo did not interfere with the auxin response of auxin-marker genes when it was co-treated with IAA, suggesting that PPBo is not an inhibitor of auxin sensing or signaling. We propose that these compounds are a class of auxin biosynthesis inhibitors that target YUC. These small molecules are powerful tools for the chemical genetic analysis of auxin function.

  6. SMPDB 2.0: big improvements to the Small Molecule Pathway Database. (United States)

    Jewison, Timothy; Su, Yilu; Disfany, Fatemeh Miri; Liang, Yongjie; Knox, Craig; Maciejewski, Adam; Poelzer, Jenna; Huynh, Jessica; Zhou, You; Arndt, David; Djoumbou, Yannick; Liu, Yifeng; Deng, Lu; Guo, An Chi; Han, Beomsoo; Pon, Allison; Wilson, Michael; Rafatnia, Shahrzad; Liu, Philip; Wishart, David S


    The Small Molecule Pathway Database (SMPDB, is a comprehensive, colorful, fully searchable and highly interactive database for visualizing human metabolic, drug action, drug metabolism, physiological activity and metabolic disease pathways. SMPDB contains >600 pathways with nearly 75% of its pathways not found in any other database. All SMPDB pathway diagrams are extensively hyperlinked and include detailed information on the relevant tissues, organs, organelles, subcellular compartments, protein cofactors, protein locations, metabolite locations, chemical structures and protein quaternary structures. Since its last release in 2010, SMPDB has undergone substantial upgrades and significant expansion. In particular, the total number of pathways in SMPDB has grown by >70%. Additionally, every previously entered pathway has been completely redrawn, standardized, corrected, updated and enhanced with additional molecular or cellular information. Many SMPDB pathways now include transporter proteins as well as much more physiological, tissue, target organ and reaction compartment data. Thanks to the development of a standardized pathway drawing tool (called PathWhiz) all SMPDB pathways are now much more easily drawn and far more rapidly updated. PathWhiz has also allowed all SMPDB pathways to be saved in a BioPAX format. Significant improvements to SMPDB's visualization interface now make the browsing, selection, recoloring and zooming of pathways far easier and far more intuitive. Because of its utility and breadth of coverage, SMPDB is now integrated into several other databases including HMDB and DrugBank.

  7. Improved Reliability of Small Molecule Organic Solar Cells by Double Anode Buffer Layers

    Directory of Open Access Journals (Sweden)

    Pao-Hsun Huang


    Full Text Available An optimized hybrid planar heterojunction (PHJ of small molecule organic solar cells (SM-OSCs based on copper phthalocyanine (CuPc as donor and fullerene (C60 as acceptor was fabricated, which obviously enhanced the performance of device by sequentially using both MoO3 and pentacene as double anode buffer layers (ABL, also known as hole extraction layer (HEL. A series of the vacuum-deposited ABL, acting as an electron and exciton blocking layer, were examined for their characteristics in SM-OSCs. The performance and reliability were compared between conventional ITO/ABL/CuPc/C60/BCP/Ag cells and the new ITO/double ABL/CuPc/C60/BCP/Ag cells. The effect on the electrical properties of these materials was also investigated to obtain the optimal thickness of ABL. The comparison shows that the modified cell has an enhanced reliability compared to traditional cells. The improvement of lifetime was attributed to the idea of double layers to prevent humidity and oxygen from diffusing into the active layer. We demonstrated that the interfacial extraction layers are necessary to avoid degradation of device. That is to say, in normal temperature and pressure, a new avenue for the device within double buffer layers has exhibited the highest values of open circuit voltage (Voc, fill factor (FF, and lifetime in this work compared to monolayer of ABL.

  8. Characterization of Two Classes of Small Molecule Inhibitors of Arp2/3 Complex

    Energy Technology Data Exchange (ETDEWEB)

    Nolen, B.; Tomasevic, N; Russell, A; Pierce, D; Jia, Z; McCormick, C; Hartman, J; Sakowicz, R; Pollard, T


    Polymerization of actin filaments directed by the actin-related protein (Arp)2/3 complex supports many types of cellular movements. However, questions remain regarding the relative contributions of Arp2/3 complex versus other mechanisms of actin filament nucleation to processes such as path finding by neuronal growth cones; this is because of the lack of simple methods to inhibit Arp2/3 complex reversibly in living cells. Here we describe two classes of small molecules that bind to different sites on the Arp2/3 complex and inhibit its ability to nucleate actin filaments. CK-0944636 binds between Arp2 and Arp3, where it appears to block movement of Arp2 and Arp3 into their active conformation. CK-0993548 inserts into the hydrophobic core of Arp3 and alters its conformation. Both classes of compounds inhibit formation of actin filament comet tails by Listeria and podosomes by monocytes. Two inhibitors with different mechanisms of action provide a powerful approach for studying the Arp2/3 complex in living cells.

  9. A small molecule screen identifies selective inhibitors of urea transporter UT-A. (United States)

    Esteva-Font, Cristina; Phuan, Puay-Wah; Anderson, Marc O; Verkman, A S


    Urea transporter (UT) proteins, including UT-A in kidney tubule epithelia and UT-B in vasa recta microvessels, facilitate urinary concentrating function. A screen for UT-A inhibitors was developed in MDCK cells expressing UT-A1, water channel aquaporin-1, and YFP-H148Q/V163S. An inwardly directed urea gradient produces cell shrinking followed by UT-A1-dependent swelling, which was monitored by YFP-H148Q/V163S fluorescence. Screening of ~90,000 synthetic small molecules yielded four classes of UT-A1 inhibitors with low micromolar half-maximal inhibitory concentration that fully and reversibly inhibited urea transport by a noncompetitive mechanism. Structure-activity analysis of >400 analogs revealed UT-A1-selective and UT-A1/UT-B nonselective inhibitors. Docking computations based on homology models of UT-A1 suggested inhibitor binding sites. UT-A inhibitors may be useful as diuretics ("urearetics") with a mechanism of action that may be effective in fluid-retaining conditions in which conventional salt transport-blocking diuretics have limited efficacy.

  10. Urearetics: a small molecule screen yields nanomolar potency inhibitors of urea transporter UT-B. (United States)

    Levin, Marc H; de la Fuente, Ricardo; Verkman, A S


    Functional studies in knockout mice indicate a critical role for urea transporters (UTs) in the urinary concentrating mechanism and in renal urea clearance. However, potent and specific urea transport blockers have not been available. Here, we used high-throughput screening to discover high-affinity, small molecule inhibitors of the UT-B urea transporter. A collection of 50,000 diverse, drug-like compounds was screened using a human erythrocyte lysis assay based on UT-B-facilitated acetamide transport. Primary screening yielded approximately 30 UT-B inhibitors belonging to the phenylsulfoxyoxazole, benzenesulfonanilide, phthalazinamine, and aminobenzimidazole chemical classes. Screening of approximately 700 structurally similar analogs gave many active compounds, the most potent of which inhibited UT-B urea transport with an EC50 of approximately 10 nM, and approximately 100% inhibition at higher concentrations. Phenylsulfoxyoxazoles and phthalazinamines also blocked rodent UT-B and had good UT-B vs. UT-A specificity. The UT-B inhibitors did not reduce aquaporin-1 (AQP1)-facilitated water transport. In AQP1-null erythrocytes, "chemical UT-B knockout" by UT-B inhibitors reduced by approximately 3-fold UT-B-mediated water transport, supporting an aqueous pore pathway through UT-B. UT-B inhibitors represent a new class of diuretics, "urearetics," which are predicted to increase renal water and solute clearance in water-retaining states.

  11. Vismodegib, a small-molecule inhibitor of the hedgehog pathway for the treatment of advanced cancers. (United States)

    De Smaele, Enrico; Ferretti, Elisabetta; Gulino, Alberto


    Vismodegib (GDC-0449) is a small, orally administrable molecule, belonging to the 2-arylpyridine class, which was discovered by Genentech Inc under a collaboration with Curis Inc. Vismodegib inhibits the Hedgehog (Hh) pathway, which is involved in tumorigenesis, thus providing a strong rationale for its use in the treatment of a variety of cancers. Vismodegib suppresses Hh signaling by binding to and interfering with smoothened, a membrane protein that provides positive signals to the Hh signaling pathway. Preclinical studies demonstrated the antitumor activity of vismodegib in mouse models of medulloblastoma (MB) and in xenograft models of colorectal and pancreatic cancer. Phase I clinical trials in patients with advanced basal cell carcinoma (BCC) and MB highlighted an objective response to vismodegib. Reported side effects were minor, with only one grade 4 adverse event. Vismodegib is currently undergoing phase II clinical trials for the treatment of advanced BCC, metastatic colorectal cancer, ovarian cancer, MB and other solid tumors. Because of its low toxicity and specificity for the Hh pathway, this drug has potential advantages compared with conventional chemotherapy, and may also be used in combination treatments. Clinical trials with other Hh inhibitors are also ongoing and their therapeutic potential will need to be compared with vismodegib.

  12. Small molecule structure correctors abolish detrimental effects of apolipoprotein E4 in cultured neurons. (United States)

    Chen, Hung-Kai; Liu, Zhaoping; Meyer-Franke, Anke; Brodbeck, Jens; Miranda, Rene D; McGuire, James G; Pleiss, Michael A; Ji, Zhong-Sheng; Balestra, Maureen E; Walker, David W; Xu, Qin; Jeong, Dah-eun; Budamagunta, Madhu S; Voss, John C; Freedman, Stephen B; Weisgraber, Karl H; Huang, Yadong; Mahley, Robert W


    Apolipoprotein E4 (apoE4), the major genetic risk factor for late onset Alzheimer disease, assumes a pathological conformation, intramolecular domain interaction. ApoE4 domain interaction mediates the detrimental effects of apoE4, including decreased mitochondrial cytochrome c oxidase subunit 1 levels, reduced mitochondrial motility, and reduced neurite outgrowth in vitro. Mutant apoE4 (apoE4-R61T) lacks domain interaction, behaves like apoE3, and does not cause detrimental effects. To identify small molecules that inhibit domain interaction (i.e. structure correctors) and reverse the apoE4 detrimental effects, we established a high throughput cell-based FRET primary assay that determines apoE4 domain interaction and secondary cell- and function-based assays. Screening a ChemBridge library with the FRET assay identified CB9032258 (a phthalazinone derivative), which inhibits domain interaction in neuronal cells. In secondary functional assays, CB9032258 restored mitochondrial cytochrome c oxidase subunit 1 levels and rescued impairments of mitochondrial motility and neurite outgrowth in apoE4-expressing neuronal cells. These benefits were apoE4-specific and dose-dependent. Modifying CB9032258 yielded well defined structure-activity relationships and more active compounds with enhanced potencies in the FRET assay (IC(50) of 23 and 116 nm, respectively). These compounds efficiently restored functional activities of apoE4-expressing cells in secondary assays. An EPR binding assay showed that the apoE4 structure correction resulted from direct interaction of a phthalazinone. With these data, a six-feature pharmacophore model was constructed for future drug design. Our results serve as a proof of concept that pharmacological intervention with apoE4 structure correctors negates apoE4 detrimental effects in neuronal cells and could be further developed as an Alzheimer disease therapeutic.

  13. Psmir: a database of potential associations between small molecules and miRNAs. (United States)

    Meng, Fanlin; Wang, Jing; Dai, Enyu; Yang, Feng; Chen, Xiaowen; Wang, Shuyuan; Yu, Xuexin; Liu, Dianming; Jiang, Wei


    miRNAs are key post-transcriptional regulators of many essential biological processes, and their dysregulation has been validated in almost all human cancers. Restoring aberrantly expressed miRNAs might be a novel therapeutics. Recently, many studies have demonstrated that small molecular compounds can affect miRNA expression. Thus, prediction of associations between small molecules and miRNAs is important for investigation of miRNA-targeted drugs. Here, we analyzed 39 miRNA-perturbed gene expression profiles, and then calculated the similarity of transcription responses between miRNA perturbation and drug treatment to predict drug-miRNA associations. At the significance level of 0.05, we obtained 6501 candidate associations between 1295 small molecules and 25 miRNAs, which included 624 FDA approved drugs. Finally, we constructed the Psmir database to store all potential associations and the related materials. In a word, Psmir served as a valuable resource for dissecting the biological significance in small molecules' effects on miRNA expression, which will facilitate developing novel potential therapeutic targets or treatments for human cancers. Psmir is supported by all major browsers, and is freely available at

  14. Electrocatalysis and electroanalysis of nickel, its oxides, hydroxides and oxyhydroxides toward small molecules. (United States)

    Miao, Yuqing; Ouyang, Lei; Zhou, Shilin; Xu, Lina; Yang, Zhuoyuan; Xiao, Mingshu; Ouyang, Ruizhuo


    The electrocatalysis toward small molecules, especially small organic compounds, is of importance in a variety of areas. Nickel based materials such as nickel, its oxides, hydroxides as well as oxyhydroxides exhibit excellent electrocatalysis performances toward many small molecules, which are widely used for fuel cells, energy storage, organic synthesis, wastewater treatment, and electrochemical sensors for pharmaceutical, medical, food or environmental analysis. Their electrocatalytic mechanisms are proposed from three aspects such as Ni(OH)2/NiOOH mediated electrolysis, direct electrocatalysis of Ni(OH)2 or NiOOH. Under exposure to air or aqueous solution, two distinct layers form on the Ni surface with a Ni hydroxide layer at the air-oxide interface and an oxide layer between the metal substrate and the outer hydroxide layer. The transformation from nickel or its oxides to hydroxides or oxyhydroxides could be further speeded up in the strong alkaline solution under the cyclic scanning at relatively high positive potential. The redox transition between Ni(OH)2 and NiOOH is also contributed to the electrocatalytic oxidation of Ni and its oxides toward small molecules in alkaline media. In addition, nickel based materials or nanomaterials, their preparations and applications are also overviewed here.

  15. Ultrasensitive in situ visualization of active glucocerebrosidase molecules

    NARCIS (Netherlands)

    Witte, Martin D.; Kallemeijn, Wouter W.; Aten, Jan; Li, Kah-Yee; Strijland, Anneke; Donker-Koopman, Wilma E.; Nieuwendijk, Adrianus M.C.H. van den; Bleijlevens, Boris; Kramer, Gertjan; Florea, Bogdan I.; Hooibrink, Berend; Hollak, Carla E.M.; Ottenhoff, Roelof; Boot, Rolf G.; Marel, Gijsbert A. van der; Overkleeft, Herman S.; Aerts, Johannes M.F.G.


    Deficiency of glucocerebrosidase (GBA) underlies Gaucher disease, a common lysosomal storage disorder. Carriership for Gaucher disease has recently been identified as major risk for parkinsonism. Presently, no method exists to visualize active GBA molecules in situ. We here report the design, synthe

  16. A geometry-based simulation of the hydration of ions and small molecules

    CERN Document Server

    Plumridge, T H


    software has been tested with a set of twenty widely varying solutes and has produced results which generally agree with experimental data for structure makers and breakers, and also agrees well with traditional techniques such as molecular dynamics and Monte Carlo techniques. The behaviour of solutes in water is of universal significance, but still not fully understood. This thesis provides details of a new computer simulation technique used to investigate the hydration of ions and small molecules. In contrast to conventional techniques such as molecular dynamics, this is a purely geometric method involving no forcefield or energy terms. Molecules of interest are modelled using crystallographic data to ensure that the structures are accurate. Water molecules are added randomly at any hydrogen bonding site in chains. At each addition the chain is rotated through all available space testing for the possibility of ring formation. The constraints used by the program to decide whether a ring should be conserved, ...

  17. Line active molecules promote inhomogeneous structures in membranes: theory, simulations and experiments. (United States)

    Palmieri, Benoit; Yamamoto, Tetsuya; Brewster, Robert C; Safran, Samuel A


    We review recent theoretical efforts that predict how line-active molecules can promote lateral heterogeneities (or domains) in model membranes. This fundamental understanding may be relevant to membrane composition in living cells, where it is thought that small domains, called lipid rafts, are necessary for the cells to be functional. The theoretical work reviewed here ranges in scale from coarse grained continuum models to nearly atomistic models. The effect of line active molecules on domain sizes and shapes in the phase separated regime or on fluctuation length scales and lifetimes in the single phase, mixed regime, of the membrane is discussed. Recent experimental studies on model membranes that include line active molecules are also presented together with some comparisons with the theoretical predictions.

  18. Comparative metabolomics reveals biogenesis of ascarosides, a modular library of small-molecule signals in C. elegans. (United States)

    von Reuss, Stephan H; Bose, Neelanjan; Srinivasan, Jagan; Yim, Joshua J; Judkins, Joshua C; Sternberg, Paul W; Schroeder, Frank C


    In the model organism Caenorhabditis elegans, a family of endogenous small molecules, the ascarosides function as key regulators of developmental timing and behavior that act upstream of conserved signaling pathways. The ascarosides are based on the dideoxysugar ascarylose, which is linked to fatty-acid-like side chains of varying lengths derived from peroxisomal β-oxidation. Despite the importance of ascarosides for many aspects of C. elegans biology, knowledge of their structures, biosynthesis, and homeostasis remains incomplete. We used an MS/MS-based screen to profile ascarosides in C. elegans wild-type and mutant metabolomes, which revealed a much greater structural diversity of ascaroside derivatives than previously reported. Comparison of the metabolomes from wild-type and a series of peroxisomal β-oxidation mutants showed that the enoyl CoA-hydratase MAOC-1 serves an important role in ascaroside biosynthesis and clarified the functions of two other enzymes, ACOX-1 and DHS-28. We show that, following peroxisomal β-oxidation, the ascarosides are selectively derivatized with moieties of varied biogenetic origin and that such modifications can dramatically affect biological activity, producing signaling molecules active at low femtomolar concentrations. Based on these results, the ascarosides appear as a modular library of small-molecule signals, integrating building blocks from three major metabolic pathways: carbohydrate metabolism, peroxisomal β-oxidation of fatty acids, and amino acid catabolism. Our screen further demonstrates that ascaroside biosynthesis is directly affected by nutritional status and that excretion of the final products is highly selective.

  19. Functionalization of hydroxyl terminated polybutadiene with biologically active fluorescent molecule

    Indian Academy of Sciences (India)

    R Murali Sankar; Subhadeep Saha; K Seeni Meera; Tushar Jana


    A biologically active molecule, 2-chloro-4,6-bis(dimethylamino)-1,3,5-triazine (CBDT), has been covalently attached at the terminal carbon atoms of the hydroxyl terminated polybutadiene (HTPB) backbone. The modification of HTPB backbone by CBDT molecule does not affect the unique physico-chemical properties such as fluidity, hydroxyl value and microstructure of the parent HTPB. The formation of hydrogen bonding between the terminal hydroxyl groups and the nitrogen atoms of triazine moiety is the driving force for the terminal attachment chemistry. The functionalized HTPB (HTPB–CBDT) shows a strong fluorescence emission at 385 nm.

  20. Small Group Activities for Introductory Business Classes. (United States)

    Mundrake, George


    Describes numerous small-group activities for the following areas of basic business education: consumer credit, marketing, business organization, entrepreneurship, insurance, risk management, economics, personal finance, business careers, global markets, and government regulation. (SK)

  1. Exploiting Transient Protein States for the Design of Small-Molecule Stabilizers of Mutant p53 (United States)

    Joerger, Andreas C.; Bauer, Matthias R.; Wilcken, Rainer; Baud, Matthias G.J.; Harbrecht, Hannes; Exner, Thomas E.; Boeckler, Frank M.; Spencer, John; Fersht, Alan R.


    Summary The destabilizing p53 cancer mutation Y220C creates an extended crevice on the surface of the protein that can be targeted by small-molecule stabilizers. Here, we identify different classes of small molecules that bind to this crevice and determine their binding modes by X-ray crystallography. These structures reveal two major conformational states of the pocket and a cryptic, transiently open hydrophobic subpocket that is modulated by Cys220. In one instance, specifically targeting this transient protein state by a pyrrole moiety resulted in a 40-fold increase in binding affinity. Molecular dynamics simulations showed that both open and closed states of this subsite were populated at comparable frequencies along the trajectories. Our data extend the framework for the design of high-affinity Y220C mutant binders for use in personalized anticancer therapy and, more generally, highlight the importance of implementing protein dynamics and hydration patterns in the drug-discovery process. PMID:26636255

  2. Organic Small Molecule as the Underlayer Toward High Performance Planar Perovskite Solar Cells. (United States)

    Cong, Shan; Yang, Hao; Lou, Yanhui; Han, Liang; Yi, Qinghua; Wang, Haibo; Sun, Yinghui; Zou, Guifu


    The underlayer plays an important role for organic-inorganic hybrid perovskite formation and charge transport in perovskite solar cells (PSCs). Here, we employ a classical organic small molecule, 5,6,11,12-tetraphenyltetracene (rubrene), as the underlayer of perovskite films to achieve 15.83% of power conversion efficiency with remarkable moisture tolerance exposed to the atmosphere. Experiments demonstrate rubrene hydrophobic underlayer not only drives the crystalline grain growth of high quality perovskite, but also contributes to the moisture tolerance of PSCs. Moreover, the matching energy level of the desirable underlayer is conductive to extracting holes and blocking electrons at anode in PSCs. This introduction of organic small molecule into PSCs provides alternative materials for interface optimization, as well as platform for flexible and wearable solar cells.

  3. Clinical grade iPS cells: need for versatile small molecules and optimal cell sources. (United States)

    Wu, Yan-Ling; Pandian, Ganesh N; Ding, Yan-Ping; Zhang, Wen; Tanaka, Yoshimasa; Sugiyama, Hiroshi


    Adult mammals possess limited ability to regenerate their lost tissues or organs. The epoch-making strategy of inducing pluripotency in somatic cells incorporates multiple applications in regenerative medicine. However, concerns about the clinical translation of induced pluripotent stem (iPS) cells still exist because of the occurrence of aberrancies, even in genome integration-free methods. As cellular reprogramming is multi-gene-oriented, versatile, bioactive small molecules could concomitantly modulate the transcriptional machinery and aid the generation of clinical grade iPS cells. The availability of optimal cell sources has additional influence on the clinical translation of iPS cells. Herein we provide a critical overview of methods and cell sources available for iPS cell production. We think the review will be a useful resource for researchers who aim to develop small molecules for speeding up the journey of iPS cells from the laboratory to the clinic.

  4. Correlating Molecular Structures with Transport Dynamics in High-Efficiency Small-Molecule Organic Photovoltaics. (United States)

    Peng, Jiajun; Chen, Yani; Wu, Xiaohan; Zhang, Qian; Kan, Bin; Chen, Xiaoqing; Chen, Yongsheng; Huang, Jia; Liang, Ziqi


    Efficient charge transport is a key step toward high efficiency in small-molecule organic photovoltaics. Here we applied time-of-flight and organic field-effect transistor to complementarily study the influences of molecular structure, trap states, and molecular orientation on charge transport of small-molecule DRCN7T (D1) and its analogue DERHD7T (D2). It is revealed that, despite the subtle difference of the chemical structures, D1 exhibits higher charge mobility, the absence of shallow traps, and better photosensitivity than D2. Moreover, charge transport is favored in the out-of-plane structure within D1-based organic solar cells, while D2 prefers in-plane charge transport.

  5. Growth factor and small molecule influence on urological tissue regeneration utilizing cell seeded scaffolds. (United States)

    Sharma, Arun K; Cheng, Earl Y


    Regenerative medicine strategies combine various attributes from multiple disciplines including stem cell biology, chemistry, materials science and medicine. The junction at which these disciplines intersect provides a means to address unmet medical needs in an assortment of pathologies with the goal of creating sustainable, functional replacement tissues. Tissue damage caused by trauma for example, requires rapid responses in order to mitigate further tissue deterioration. Cell/scaffold composites have been utilized to initiate and stabilize regenerative responses in vivo with the hope that functional tissue can be attained. Along with the gross reconfiguration of regenerating tissues, small molecules and growth factors also play a pivotal role in tissue regeneration. Several regenerative studies targeting a variety of urological tissues demonstrate the utility of these small molecules or growth factors in an in vivo setting.

  6. Influence of Electrostatics on Small Molecule Flux through a Protein Nanoreactor. (United States)

    Glasgow, Jeff E; Asensio, Michael A; Jakobson, Christopher M; Francis, Matthew B; Tullman-Ercek, Danielle


    Nature uses protein compartmentalization to great effect for control over enzymatic pathways, and the strategy has great promise for synthetic biology. In particular, encapsulation in nanometer-sized containers to create nanoreactors has the potential to elicit interesting, unexplored effects resulting from deviations from well-understood bulk processes. Self-assembled protein shells for encapsulation are especially desirable for their uniform structures and ease of perturbation through genetic mutation. Here, we use the MS2 capsid, a well-defined porous 27 nm protein shell, as an enzymatic nanoreactor to explore pore-structure effects on substrate and product flux during the catalyzed reaction. Our results suggest that the shell can influence the enzymatic reaction based on charge repulsion between small molecules and point mutations around the pore structure. These findings also lend support to the hypothesis that protein compartments modulate the transport of small molecules and thus influence metabolic reactions and catalysis in vitro.

  7. Small Molecule-Photoactive Yellow Protein Labeling Technology in Live Cell Imaging

    Directory of Open Access Journals (Sweden)

    Feng Gao


    Full Text Available Characterization of the chemical environment, movement, trafficking and interactions of proteins in live cells is essential to understanding their functions. Labeling protein with functional molecules is a widely used approach in protein research to elucidate the protein location and functions both in vitro and in live cells or in vivo. A peptide or a protein tag fused to the protein of interest and provides the opportunities for an attachment of small molecule probes or other fluorophore to image the dynamics of protein localization. Here we reviewed the recent development of no-wash small molecular probes for photoactive yellow protein (PYP-tag, by the means of utilizing a quenching mechanism based on the intramolecular interactions, or an environmental-sensitive fluorophore. Several fluorogenic probes have been developed, with fast labeling kinetics and cell permeability. This technology allows quick live-cell imaging of cell-surface and intracellular proteins without a wash-out procedure.

  8. UP-scaling of inverted small molecule based organic solar cells

    DEFF Research Database (Denmark)

    Patil, Bhushan Ramesh; Madsen, Morten

    Organic solar cells (OSC), in spite of being a promising technology, still face challenges regarding large-scale fabrication. Although efficiencies of up to 12 % has been reached for small molecule OSC, their performance, both in terms of device efficiency and stability, is significantly reduced...... during up-scaling processes. The work presented here is focused on an approach towards up-scaling of small molecule based OSC with inverted device configuration. Bilayer OSC from Tetraphenyldibenzoperiflanthene (DBP) and Fullerenes (C70), as electron donor and acceptor respectively, with cell area...... ranging on a scale from a few mm2 to cm2, are produced by organic molecular beam deposition (OMBD). All the layers in the device are fabricated from a highly sophisticated vacuum cluster deposition system that includes electrode, interfacial layer and organic layer deposition in one high-vacuum deposition...

  9. Using RosettaLigand for small molecule docking into comparative models.

    Directory of Open Access Journals (Sweden)

    Kristian W Kaufmann

    Full Text Available Computational small molecule docking into comparative models of proteins is widely used to query protein function and in the development of small molecule therapeutics. We benchmark RosettaLigand docking into comparative models for nine proteins built during CASP8 that contain ligands. We supplement the study with 21 additional protein/ligand complexes to cover a wider space of chemotypes. During a full docking run in 21 of the 30 cases, RosettaLigand successfully found a native-like binding mode among the top ten scoring binding modes. From the benchmark cases we find that careful template selection based on ligand occupancy provides the best chance of success while overall sequence identity between template and target do not appear to improve results. We also find that binding energy normalized by atom number is often less than -0.4 in native-like binding modes.

  10. The logic and design of analog-sensitive kinases and their small molecule inhibitors. (United States)

    Lopez, Michael S; Kliegman, Joseph I; Shokat, Kevan M


    Analog-sensitive AS Kinase technology allows for rapid, reversible, and highly specific inhibition of individual engineered kinases in cells and in mouse models of human diseases. The technique consists of two parts: a kinase containing a space-creating mutation in the ATP-binding pocket and a bulky ATP-competitive small molecule inhibitor that complements the shape of the mutant ATP pocket. This strategy enables dissection of phospho-signaling pathways, elucidation of the physiological function of individual kinases, and characterization of the pharmacology of clinical-kinase inhibitors. Here, we present an overview of AS technology and describe a stepwise approach for generating AS Kinase mutants and identifying appropriate small molecule inhibitors. We also describe commonly encountered technical obstacles and provide strategies to overcome them.

  11. A philicity based analysis of adsorption of small molecules in zeolites

    Indian Academy of Sciences (India)

    Angeles Cáun; Marcelo Galván; Pratim Kumar Chattaraj


    Adsorption of small molecules like CH4, CO and NH3 into the acid sites of zeolites is analysed as an interaction between an electrophile and a nucleophile. Global reactivity descriptors like softness and electrophilicity, and local reactivity descriptors like the Fukui function, local softness and local philicity are calculated within density functional as well as Hartree-Fock frameworks using both Mulliken and Hirshfeld population analysis schemes. The HSAB principle and the best electrophilenucleophile combination suggest that the reaction between the NH3 and Brönsted acid site of the zeolite is the strongest. Interaction between the zeolite and a small probe molecule takes place through the most electrophilic atom of one with the most nucleophilic atom of the other. This result is in conformity with those provided by the frontier orbital theory and the local HSAB principle.

  12. RNA targeting by small molecules: Binding of protoberberine, benzophenanthridine and aristolochia alkaloids to various RNA structures

    Indian Academy of Sciences (India)

    Gopinatha Suresh Kumar


    Studies on RNA targeting by small molecules to specifically control certain cellular functions is an area of remarkable current interest. For this purpose, a basic understanding of the molecular aspects of the interaction of small molecules with various RNA structures is essential. Alkaloids are a group of natural products with potential therapeutic utility, and very recently, their interaction with many RNA structures have been reported. Especially noteworthy are the protoberberines and aristolochia alkaloids distributed widely in many botanical families. Many of the alkaloids of these group exhibit excellent binding affinity to many RNA structures that may be exploited to develop RNA targeted therapeutics. This review attempts to present the current status on the understanding of the interaction of these alkaloids with various RNA structures, mainly highlighting the biophysical aspects.

  13. Blu-ray based optomagnetic aptasensor for detection of small molecules

    DEFF Research Database (Denmark)

    Yang, Jaeyoung; Donolato, Marco; Pinto, Alessandro


    This paper describes an aptamer-based optomagnetic biosensor for detection of a small molecule based on target binding-induced inhibition of magnetic nanoparticle (MNP) clustering. For the detection of a target small molecule, two mutually exclusive binding reactions (aptamer-target binding...... and aptamer-DNA linker hybridization) are designed. An aptamer specific to the target and a DNA linker complementary to a part of the aptamer sequence are immobilized onto separate MNPs. Hybridization of the DNA linker and the aptamer induces formation of MNP clusters. The target-to-aptamer binding on MNPs...... prior to the addition of linker-functionalized MNPs significantly hinders the hybridization reaction, thus reducing the degree of MNP clustering. The clustering state, which is thus related to the target concentration, is then quantitatively determined by an optomagnetic readout technique that provides...

  14. A DNA-Mediated Homogeneous Binding Assay for Proteins and Small Molecules

    DEFF Research Database (Denmark)

    Zhang, Zhao; Hejesen, Christian; Kjelstrup, Michael Brøndum


    Optical detection of molecular targets typically requires immobilization, separation, or chemical or enzymatic processing. An important exception is aptamers that allow optical detection in solution based on conformational changes. This method, however, requires the laborious selection of aptamers...... with high target specificity and affinity, and the ability to undergo the required conformational changes. Here we report on an alternative generic scheme for detecting small molecules and proteins in solution based on a shift in the equilibrium of DNA-based strand displacement competition reaction....... The shift occurs upon binding of a protein, for example, an antibody to its target. We demonstrate nanomolar detection of small molecules such as biotin, digoxigenin, vitamin D, and folate, in buffer and in plasma. The method is flexible, and we also show nanomolar detection of the respective antibodies...

  15. Structure-based DNA-targeting strategies with small molecule ligands for drug discovery. (United States)

    Sheng, Jia; Gan, Jianhua; Huang, Zhen


    Nucleic acids are the molecular targets of many clinical anticancer drugs. However, compared with proteins, nucleic acids have traditionally attracted much less attention as drug targets in structure-based drug design, partially because limited structural information of nucleic acids complexed with potential drugs is available. Over the past several years, enormous progresses in nucleic acid crystallization, heavy-atom derivatization, phasing, and structural biology have been made. Many complicated nucleic acid structures have been determined, providing new insights into the molecular functions and interactions of nucleic acids, especially DNAs complexed with small molecule ligands. Thus, opportunities have been created to further discover nucleic acid-targeting drugs for disease treatments. This review focuses on the structure studies of DNAs complexed with small molecule ligands for discovering lead compounds, drug candidates, and/or therapeutics.

  16. Biomarkers for Tuberculosis Based on Secreted, Species-Specific, Bacterial Small Molecules. (United States)

    Pan, Shih-Jung; Tapley, Asa; Adamson, John; Little, Tessa; Urbanowski, Michael; Cohen, Keira; Pym, Alexander; Almeida, Deepak; Dorasamy, Afton; Layre, Emilie; Young, David C; Singh, Ravesh; Patel, Vinod B; Wallengren, Kristina; Ndung'u, Thumbi; Wilson, Douglas; Moody, D Branch; Bishai, William


    Improved biomarkers are needed for tuberculosis. To develop tests based on products secreted by tubercle bacilli that are strictly associated with viability, we evaluated 3 bacterial-derived, species-specific, small molecules as biomarkers: 2 mycobactin siderophores and tuberculosinyladenosine. Using liquid chromatography-tandem mass spectrometry, we demonstrated the presence of 1 or both mycobactins and/or tuberculosinyladenosine in serum and whole lung tissues from infected mice and sputum, cerebrospinal fluid (CSF), or lymph nodes from infected patients but not uninfected controls. Detection of the target molecules distinguished host infection status in 100% of mice with both serum and lung as the target sample. In human subjects, we evaluated detection of the bacterial small molecules (BSMs) in multiple body compartments in 3 patient cohorts corresponding to different forms of tuberculosis. We detected at least 1 of the 3 molecules in 90%, 71%, and 40% of tuberculosis patients' sputum, CSF, and lymph node samples, respectively. In paucibacillary forms of human tuberculosis, which are difficult to diagnose even with culture, detection of 1 or more BSM was rapid and compared favorably to polymerase chain reaction-based detection. Secreted BSMs, detectable in serum, warrant further investigation as a means for diagnosis and therapeutic monitoring in patients with tuberculosis.

  17. Small Molecule Inhibitors of Bcl-2 Family Proteins for Pancreatic Cancer Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Masood, Ashiq [Department of Internal Medicine/Pathology, Karmanos Cancer Institute, Wayne State University, 4100 John R, HWCRC 732, Detroit, MI 48201 (United States); Azmi, Asfar S. [Department of Pathology, Karmanos Cancer Institute, Wayne State University, 4100 John R, HWCRC 732, Detroit MI 48201 (United States); Mohammad, Ramzi M., E-mail: [Department of Internal Medicine/Pathology, Karmanos Cancer Institute, Wayne State University, 4100 John R, HWCRC 732, Detroit, MI 48201 (United States); Department of Oncology, Karmanos Cancer Institute, 4100 John R, HWCRC 732, Detroit, MI 48201 (United States)


    Pancreatic cancer (PC) has a complex etiology and displays a wide range of cellular escape pathways that allow it to resist different treatment modalities. Crucial signaling molecules that function downstream of the survival pathways, particularly at points where several of these pathways crosstalk, provide valuable targets for the development of novel anti-cancer drugs. Bcl-2 family member proteins are anti-apoptotic molecules that are known to be overexpressed in most cancers including PC. The anti-apoptotic machinery has been linked to the observed resistance developed to chemotherapy and radiation and therefore is important from the targeted drug development point of view. Over the past ten years, our group has extensively studied a series of small molecule inhibitors of Bcl-2 against PC and provide solid preclinical platform for testing such novel drugs in the clinic. This review examines the efficacy, potency, and function of several small molecule inhibitor drugs targeted to the Bcl-2 family of proteins and their preclinical progress against PC. This article further focuses on compounds that have been studied the most and also discusses the anti-cancer potential of newer class of Bcl-2 drugs.

  18. Role of Adhesion Molecules in Eosinophil Activation: A Comparative Study on the Effect of Adhesion Molecules on Eosinophil Survival

    Directory of Open Access Journals (Sweden)

    Kazutoshi Yamaguchi


    Conclusions: The regulation of adhesion molecules, by not only preventing eosinophil adhesion but also eosinophil activation, may be a potential target in the treatment of allergic inflammatory disorders.

  19. DEPTH: a web server to compute depth and predict small-molecule binding cavities in proteins. (United States)

    Tan, Kuan Pern; Varadarajan, Raghavan; Madhusudhan, M S


    Depth measures the extent of atom/residue burial within a protein. It correlates with properties such as protein stability, hydrogen exchange rate, protein-protein interaction hot spots, post-translational modification sites and sequence variability. Our server, DEPTH, accurately computes depth and solvent-accessible surface area (SASA) values. We show that depth can be used to predict small molecule ligand binding cavities in proteins. Often, some of the residues lining a ligand binding cavity are both deep and solvent exposed. Using the depth-SASA pair values for a residue, its likelihood to form part of a small molecule binding cavity is estimated. The parameters of the method were calibrated over a training set of 900 high-resolution X-ray crystal structures of single-domain proteins bound to small molecules (molecular weight structures. Users have the option of tuning several parameters to detect cavities of different sizes, for example, geometrically flat binding sites. The input to the server is a protein 3D structure in PDB format. The users have the option of tuning the values of four parameters associated with the computation of residue depth and the prediction of binding cavities. The computed depths, SASA and binding cavity predictions are displayed in 2D plots and mapped onto 3D representations of the protein structure using Jmol. Links are provided to download the outputs. Our server is useful for all structural analysis based on residue depth and SASA, such as guiding site-directed mutagenesis experiments and small molecule docking exercises, in the context of protein functional annotation and drug discovery.

  20. Identification of small molecule binding sites within proteins using phage display technology.

    Energy Technology Data Exchange (ETDEWEB)

    Rodi, D. J.; Agoston, G. E.; Manon, R.; Lapcevich, R.; Green, S. J.; Makowski, L.; Biosciences Division; EntreMed Inc.; Florida State Univ.


    Affinity selection of peptides displayed on phage particles was used as the basis for mapping molecular contacts between small molecule ligands and their protein targets. Analysis of the crystal structures of complexes between proteins and small molecule ligands revealed that virtually all ligands of molecular weight 300 Da or greater have a continuous binding epitope of 5 residues or more. This observation led to the development of a technique for binding site identification which involves statistical analysis of an affinity-selected set of peptides obtained by screening of libraries of random, phage-displayed peptides against small molecules attached to solid surfaces. A random sample of the selected peptides is sequenced and used as input for a similarity scanning program which calculates cumulative similarity scores along the length of the putative receptor. Regions of the protein sequence exhibiting the highest similarity with the selected peptides proved to have a high probability of being involved in ligand binding. This technique has been employed successfully to map the contact residues in multiple known targets of the anticancer drugs paclitaxel (Taxol), docetaxel (Taxotere) and 2-methoxyestradiol and the glycosaminoglycan hyaluronan, and to identify a novel paclitaxel receptor [1]. These data corroborate the observation that the binding properties of peptides displayed on the surface of phage particles can mimic the binding properties of peptides in naturally occurring proteins. It follows directly that structural context is relatively unimportant for determining the binding properties of these disordered peptides. This technique represents a novel, rapid, high resolution method for identifying potential ligand binding sites in the absence of three-dimensional information and has the potential to greatly enhance the speed of development of novel small molecule pharmaceuticals.

  1. A Small Molecule that Induces Intrinsic Pathway Apoptosis with Unparalleled Speed


    Rahul Palchaudhuri; Michael J. Lambrecht; Rachel C. Botham; Kathryn C. Partlow; Tjakko J. van Ham; Karson S. Putt; Laurie T. Nguyen; Seok-Ho Kim; Randall T. Peterson; Timothy M. Fan; Paul J. Hergenrother


    textabstractApoptosis is generally believed to be a process thatrequires several hours, in contrast to non-programmed forms of cell death that can occur in minutes. Our findings challenge the time-consuming nature of apoptosis as we describe the discovery and characterization of a small molecule, named Raptinal, which initiates intrinsic pathway caspase-dependent apoptosis within minutes in multiple cell lines. Comparison to a mechanistically diverse panel of apoptotic stimuli reveals that Ra...

  2. Label-free detection of small-molecule binding to a GPCR in the membrane environment. (United States)

    Heym, Roland G; Hornberger, Wilfried B; Lakics, Viktor; Terstappen, Georg C


    Evaluation of drug-target interaction kinetics is becoming increasingly important during the drug-discovery process to investigate selectivity of a drug and predict in vivo target occupancy. To date, it remains challenging to obtain kinetic information for interactions between G-protein-coupled receptors (GPCRs) and small-molecule ligands in a label-free manner. Often GPCRs need to be solubilized or even stabilized by mutations which can be difficult and is time consuming. In addition, it is often unclear if the native conformation of the receptors is sustained. In this study, surface plasmon resonance (SPR) and surface acoustic wave (SAW) technologies have been used to detect ligand binding to the GPCR chemokine (C-X-C motif) receptor 4 (CXCR4) expressed in lipoparticles. We first evaluated different strategies to immobilize CXCR4-expressing lipoparticles. The highest small-molecule binding signal in SPR and SAW was achieved with a matrix-free carboxymethylated sensor chip coated with wheat germ agglutinin for lipoparticle capturing. Next, the binding kinetics of the anti-CXCR4 antibody 12G5 raised against a conformational epitope (k(on)=1.83×10(6)M(-1)s(-1), k(off)=2.79×10(-4) s(-1)) and the small molecule AMD3100 (k(on)=5.46×10(5)M(-1)s(-1), k(off)=1.01×10(-2)s(-1)) were assessed by SAW. Our kinetic and affinity data are consistent with previously published radioligand-binding experiments using cells and label-free experiments with solubilized CXCR4. This is the first study demonstrating label-free kinetic characterization of small-molecule binding to a GPCR in the membrane environment. The presented method holds the potential to greatly facilitate label-free assay development for GPRCs that can be expressed at high levels in lipoparticles.

  3. Introduction: MicroRNAs in human reproduction: small molecules with crucial regulatory roles. (United States)

    Imbar, Tal; Galliano, Daniela; Pellicer, Antonio; Laufer, Neri


    MicroRNAs constitute a large family of approximately 21-nucleotide-long, noncoding RNAs. They emerged more than 20 years ago as key posttranscriptional regulators of gene expression. The regulatory role of these small RNA molecules has recently begun to be explored in the human reproductive system. In this issue's Views and Reviews, the authors present the current knowledge regarding the involvement of microRNAs in several aspects of human reproduction and discuss its future implications for clinical practice.

  4. Process Intensification Tools in the Small‐Scale Pharmaceutical Manufacturing of Small Molecules

    DEFF Research Database (Denmark)

    Mitic, Aleksandar; Gernaey, Krist V.


    The chemical process industry is paying significant attention to the intensification of processes with the main aim of achieving increased productivity, improved economic status, and enhanced sustainability. The pharmaceutical industry is moving in the same direction and, therefore, dozens...... of processes are in a state of change. However, it is important to note that not all processes can be intensified easily, such as slow chemical reactions, processes with solids, slurries, and on the like. This review summarizes applications of promising tools for achieving process intensification in the small......‐scale pharmaceutical manufacturing of so‐called small molecules. The focus is on microwave radiation, microreactors, ultrasounds, and meso‐scale tubular reactors....

  5. A small molecule (pluripotin as a tool for studying cancer stem cell biology: proof of concept.

    Directory of Open Access Journals (Sweden)

    Susan D Mertins

    Full Text Available BACKGROUND: Cancer stem cells (CSC are thought to be responsible for tumor maintenance and heterogeneity. Bona fide CSC purified from tumor biopsies are limited in supply and this hampers study of CSC biology. Furthermore, purified stem-like CSC subpopulations from existing tumor lines are unstable in culture. Finding a means to overcome these technical challenges would be a useful goal. In a first effort towards this, we examined whether a chemical probe that promotes survival of murine embryonic stem cells without added exogenous factors can alter functional characteristics in extant tumor lines in a fashion consistent with a CSC phenotype. METHODOLOGY/PRINCIPAL FINDINGS: The seven tumor lines of the NCI60 colon subpanel were exposed to SC-1 (pluripotin, a dual kinase and GTPase inhibitor that promotes self-renewal, and then examined for tumorigenicity under limiting dilution conditions and clonogenic activity in soft agar. A statistically significant increase in tumor formation following SC-1 treatment was observed (p<0.04. Cloning efficiencies and expression of putative CSC surface antigens (CD133 and CD44 were also increased. SC-1 treatment led to sphere formation in some colon tumor lines. Finally, SC-1 inhibited in vitro kinase activity of RSK2, and another RSK2 inhibitor increased colony formation implicating a role for this kinase in eliciting a CSC phenotype. CONCLUSIONS/SIGNIFICANCE: These findings validate a proof of concept study exposure of extant tumor lines to a small molecule may provide a tractable in vitro model for understanding CSC biology.

  6. Identification of verrucarin a as a potent and selective steroid receptor coactivator-3 small molecule inhibitor.

    Directory of Open Access Journals (Sweden)

    Fei Yan

    Full Text Available Members of the steroid receptor coactivator (SRC family are overexpressed in numerous types of cancers. In particular, steroid receptor coactivator 3 (SRC-3 has been recognized as a critical coactivator associated with tumor initiation, progression, recurrence, metastasis, and chemoresistance where it interacts with multiple nuclear receptors and other transcription factors to enhance their transcriptional activities and facilitate cross-talk between pathways that stimulate cancer progression. Because of its central role as an integrator of growth signaling pathways, development of small molecule inhibitors (SMIs against SRCs have the potential to simultaneously disrupt multiple signal transduction networks and transcription factors involved in tumor progression. Here, high-throughput screening was performed to identify compounds able to inhibit the intrinsic transcriptional activities of the three members of the SRC family. Verrucarin A was identified as a SMI that can selectively promote the degradation of the SRC-3 protein, while affecting SRC-1 and SRC-2 to a lesser extent and having no impact on CARM-1 and p300 protein levels. Verrucarin A was cytotoxic toward multiple types of cancer cells at low nanomolar concentrations, but not toward normal liver cells. Moreover, verrucarin A was able to inhibit expression of the SRC-3 target genes MMP2 and MMP13 and attenuated cancer cell migration. We found that verrucarin A effectively sensitized cancer cells to treatment with other anti-cancer drugs. Binding studies revealed that verrucarin A does not bind directly to SRC-3, suggesting that it inhibits SRC-3 through its interaction with an upstream effector. In conclusion, unlike other SRC SMIs characterized by our laboratory that directly bind to SRCs, verrucarin A is a potent and selective SMI that blocks SRC-3 function through an indirect mechanism.

  7. Rapid Discovery of Functional Small Molecule Ligands against Proteomic Targets through Library-Against-Library Screening. (United States)

    Wu, Chun-Yi; Wang, Don-Hong; Wang, Xiaobing; Dixon, Seth M; Meng, Liping; Ahadi, Sara; Enter, Daniel H; Chen, Chao-Yu; Kato, Jason; Leon, Leonardo J; Ramirez, Laura M; Maeda, Yoshiko; Reis, Carolina F; Ribeiro, Brianna; Weems, Brittany; Kung, Hsing-Jien; Lam, Kit S


    Identifying "druggable" targets and their corresponding therapeutic agents are two fundamental challenges in drug discovery research. The one-bead-one-compound (OBOC) combinatorial library method has been developed to discover peptides or small molecules that bind to a specific target protein or elicit a specific cellular response. The phage display cDNA expression proteome library method has been employed to identify target proteins that interact with specific compounds. Here, we combined these two high-throughput approaches, efficiently interrogated approximately 10(13) possible molecular interactions, and identified 91 small molecule compound beads that interacted strongly with the phage library. Of 19 compounds resynthesized, 4 were cytotoxic against cancer cells; one of these compounds was found to interact with EIF5B and inhibit protein translation. As more binding pairs are confirmed and evaluated, the "library-against-library" screening approach and the resulting small molecule-protein domain interaction database may serve as a valuable tool for basic research and drug development.