A New Publicly Available Chemical Query Language, CSRML ...

EPA Pesticide Factsheets

A new XML-based query language, CSRML, has been developed for representing chemical substructures, molecules, reaction rules, and reactions. CSRML queries are capable of integrating additional forms of information beyond the simple substructure (e.g., SMARTS) or reaction transformation (e.g., SMIRKS, reaction SMILES) queries currently in use. Chemotypes, a term used to represent advanced CSRML queries for repeated application can be encoded not only with connectivity and topology, but also with properties of atoms, bonds, electronic systems, or molecules. The CSRML language has been developed in parallel with a public set of chemotypes, i.e., the ToxPrint chemotypes, which are designed to provide excellent coverage of environmental, regulatory and commercial use chemical space, as well as to represent features and frameworks believed to be especially relevant to toxicity concerns. A software application, ChemoTyper, has also been developed and made publicly available to enable chemotype searching and fingerprinting against a target structure set. The public ChemoTyper houses the ToxPrint chemotype CSRML dictionary, as well as reference implementation so that the query specifications may be adopted by other chemical structure knowledge systems. The full specifications of the XML standard used in CSRML-based chemotypes are publicly available to facilitate and encourage the exchange of structural knowledge. Paper details specifications for a new XML-based query lan

Interrogating alkyl and arylalkylpolyamino (bis)urea and (bis)thiourea isosteres as potent antimalarial chemotypes against multiple lifecycle forms of Plasmodium falciparum parasites.

PubMed

Verlinden, Bianca K; de Beer, Marna; Pachaiyappan, Boobalan; Besaans, Ethan; Andayi, Warren A; Reader, Janette; Niemand, Jandeli; van Biljon, Riette; Guy, Kiplin; Egan, Timothy; Woster, Patrick M; Birkholtz, Lyn-Marie

2015-08-15

A new series of potent potent aryl/alkylated (bis)urea- and (bis)thiourea polyamine analogues were synthesized and evaluated in vitro for their antiplasmodial activity. Altering the carbon backbone and terminal substituents increased the potency of analogues in the compound library 3-fold, with the most active compounds, 15 and 16, showing half-maximal inhibitory concentrations (IC50 values) of 28 and 30 nM, respectively, against various Plasmodium falciparum parasite strains without any cross-resistance. In vitro evaluation of the cytotoxicity of these analogues revealed marked selectivity towards targeting malaria parasites compared to mammalian HepG2 cells (>5000-fold lower IC50 against the parasite). Preliminary biological evaluation of the polyamine analogue antiplasmodial phenotype revealed that (bis)urea compounds target parasite asexual proliferation, whereas (bis)thiourea compounds of the same series have the unique ability to block transmissible gametocyte forms of the parasite, indicating pluripharmacology against proliferative and non-proliferative forms of the parasite. In this manuscript, we describe these results and postulate a refined structure-activity relationship (SAR) model for antiplasmodial polyamine analogues. The terminally aryl/alkylated (bis)urea- and (bis)thiourea-polyamine analogues featuring a 3-5-3 or 3-6-3 carbon backbone represent a structurally novel and distinct class of potential antiplasmodials with activities in the low nanomolar range, and high selectivity against various lifecycle forms of P. falciparum parasites. Copyright © 2015 Elsevier Ltd. All rights reserved.

Increasing Chemical Space Coverage by Combining Empirical and Computational Fragment Screens

PubMed Central

2015-01-01

Most libraries for fragment-based drug discovery are restricted to 1,000–10,000 compounds, but over 500,000 fragments are commercially available and potentially accessible by virtual screening. Whether this larger set would increase chemotype coverage, and whether a computational screen can pragmatically prioritize them, is debated. To investigate this question, a 1281-fragment library was screened by nuclear magnetic resonance (NMR) against AmpC β-lactamase, and hits were confirmed by surface plasmon resonance (SPR). Nine hits with novel chemotypes were confirmed biochemically with KI values from 0.2 to low mM. We also computationally docked 290,000 purchasable fragments with chemotypes unrepresented in the empirical library, finding 10 that had KI values from 0.03 to low mM. Though less novel than those discovered by NMR, the docking-derived fragments filled chemotype holes from the empirical library. Crystal structures of nine of the fragments in complex with AmpC β-lactamase revealed new binding sites and explained the relatively high affinity of the docking-derived fragments. The existence of chemotype holes is likely a general feature of fragment libraries, as calculation suggests that to represent the fragment substructures of even known biogenic molecules would demand a library of minimally over 32,000 fragments. Combining computational and empirical fragment screens enables the discovery of unexpected chemotypes, here by the NMR screen, while capturing chemotypes missing from the empirical library and tailored to the target, with little extra cost in resources. PMID:24807704

Synthesis and structure-activity relationships of imidazo[1,2-a]pyrimidin-5(1H)-ones as a novel series of beta isoform selective phosphatidylinositol 3-kinase inhibitors.

PubMed

Lin, Hong; Erhard, Karl; Hardwicke, Mary Ann; Luengo, Juan I; Mack, James F; McSurdy-Freed, Jeanelle; Plant, Ramona; Raha, Kaushik; Rominger, Cynthia M; Sanchez, Robert M; Schaber, Michael D; Schulz, Mark J; Spengler, Michael D; Tedesco, Rosanna; Xie, Ren; Zeng, Jin J; Rivero, Ralph A

2012-03-15

A series of PI3K-beta selective inhibitors, imidazo[1,2-a]-pyrimidin-5(1H)-ones, has been rationally designed based on the docking model of the more potent R enantiomer of TGX-221, identified by a chiral separation, in a PI3K-beta homology model. Synthesis and SAR of this novel chemotype are described. Several compounds in the series demonstrated potent growth inhibition in a PTEN-deficient breast cancer cell line MDA-MB-468 under anchorage independent conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Chemical genetics of Plasmodium falciparum

PubMed Central

Guiguemde, W. Armand; Shelat, Anang A.; Bouck, David; Duffy, Sandra; Crowther, Gregory J.; Davis, Paul H.; Smithson, David C.; Connelly, Michele; Clark, Julie; Zhu, Fangyi; Jiménez-Díaz, María B; Martinez, María S; Wilson, Emily B.; Tripathi, Abhai K.; Gut, Jiri; Sharlow, Elizabeth R.; Bathurst, Ian; El Mazouni, Farah; Fowble, Joseph W; Forquer, Isaac; McGinley, Paula L; Castro, Steve; Angulo-Barturen, Iñigo; Ferrer, Santiago; Rosenthal, Philip J.; DeRisi, Joseph L; Sullivan, David J.; Lazo, John S.; Roos, David S.; Riscoe, Michael K.; Phillips, Margaret A.; Rathod, Pradipsinh K.; Van Voorhis, Wesley C.; Avery, Vicky M; Guy, R. Kiplin

2010-01-01

Malaria caused by Plasmodium falciparum is a catastrophic disease worldwide (880,000 deaths yearly). Vaccine development has proved difficult and resistance has emerged for most antimalarials. In order to discover new antimalarial chemotypes, we have employed a phenotypic forward chemical genetic approach to assay 309,474 chemicals. Here we disclose structures and biological activity of the entire library, many of which exhibited potent in vitro activity against drug resistant strains, and detailed profiling of 172 representative candidates. A reverse chemical genetic study identified 19 new inhibitors of 4 validated drug targets and 15 novel binders among 61 malarial proteins. Phylochemogenetic profiling in multiple organisms revealed similarities between Toxoplasma gondii and mammalian cell lines and dissimilarities between P. falciparum and related protozoans. One exemplar compound displayed efficacy in a murine model. Overall, our findings provide the scientific community with new starting points for malaria drug discovery. PMID:20485428

A High-Throughput Screening Assay to Detect ...

EPA Pesticide Factsheets

In support of the Endocrine Disruption Screening Program (EDSP21), the US EPA ToxCast program is developing assays to enable screening for chemicals that may disrupt thyroid hormone synthesis. Thyroperoxidase (TPO) is critical for TH synthesis and is a known target of thyroid-disrupting chemicals that adversely impact neurodevelopment. The AUR-TPO assay was recently developed to screen >1,900 ToxCast chemicals for potential TPO inhibition activity. Parallel assays were used to determine which AUR-TPO actives were more selective for TPO inhibition. Additionally, the TPO inhibition activities of 150 chemicals were compared between the AUR-TPO assay and an orthogonal peroxidase oxidation assay using guaiacol as substrate to confirm putative TPO inhibition profiles. Bioactivity results from the AUR-TPO assay were used to identify chemical substructures associated with in vitro TPO inhibition. Substructure profiles were generated for each chemical in the ToxCast test set using the publicly-available ToxPrint 2.0 chemotypes. Chemotypes enriched among the putative TPO inhibitors were identified using a cumulative hypergeometric probability (p < 0.01). Of the total 729 chemotypes evaluated, 44 were overrepresented among TPO inhibitors. Another 24 chemotypes were found to be significantly underrepresented among AUR-TPO actives. Examination of these chemotypes revealed four basic pharmacophores that accounted for 70% of the ToxCast chemicals active in the AUR-TPO assay:

Discovery of pyridyl sulfonamide 11-beta-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitors for the treatment of metabolic disorders.

PubMed

Yoon, David S; Wu, Shung C; Seethala, Ramakrishna; Golla, Rajasree; Nayeem, Akbar; Everlof, John G; Gordon, David A; Hamann, Lawrence G; Robl, Jeffrey A

2014-11-01

A previous disclosure from this lab highlighted the discovery of pyridyl amides as potent 11β-HSD1 inhibitors. In order to build additional novelty and polarity into this chemotype, replacement of the hydrogen-bonding carbonyl (CO) pharmacophore with the bioisosteric sulfonyl (SO2) group was examined. Despite initial comparisons suggesting the corresponding sulfonamides exhibited weaker activity versus their carbonyl counterparts, further optimization was performed in an effort to identify various potent and unique leads for the program. Judicious incorporation of polar moieties resulted in the identification of compounds with enhanced potency and lipophilicity profiles, resulting in leads with superior aqueous solubility and liver microsomal stability. Copyright © 2014 Elsevier Ltd. All rights reserved.

The putative endocannabinoid transport blocker LY2183240 is a potent inhibitor of FAAH and several other brain serine hydrolases.

PubMed

Alexander, Jessica P; Cravatt, Benjamin F

2006-08-02

How lipid transmitters move within and between cells to communicate signals remains an important and largely unanswered question. Integral membrane transporters, soluble lipid-binding proteins, and metabolic enzymes have all been proposed to collaboratively regulate lipid signaling dynamics in vivo. Assignment of the relative contributions made by each of these classes of proteins requires selective pharmacological agents to perturb their individual functions. Recently, LY2183240, a heterocyclic urea inhibitor of the putative endocannabinoid (EC) transporter, was shown to disrupt the cellular uptake of the lipid EC anandamide and promote analgesia in vivo. Here, we show that LY2183240 is a potent, covalent inhibitor of the EC-degrading enzyme fatty acid amide hydrolase (FAAH). LY2183240 inactivates FAAH by carbamylation of the enzyme's serine nucleophile. More global screens using activity-based proteomic probes identified several additional serine hydrolases that are also inhibited by LY2183240. These results indicate that the blockade of anandamide uptake observed with LY2183240 may be due primarily to the inactivation of FAAH, providing further evidence that this enzyme serves as a metabolic driving force that promotes the diffusion of anandamide into cells. More generally, the proteome-wide target promiscuity of LY2183240 designates the heterocyclic urea as a chemotype with potentially excessive protein reactivity for drug design.

Synthesis and P1' SAR exploration of potent macrocyclic tissue factor-factor VIIa inhibitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ladziata, Vladimir; Glunz, Peter W.; Zou, Yan

Selective tissue factor-factor VIIa complex (TF-FVIIa) inhibitors are viewed as promising compounds for treating thrombotic disease. In this contribution, we describe multifaceted exploratory SAR studies of S1'-binding moieties within a macrocyclic chemotype aimed at replacing cyclopropyl sulfone P1' group. Over the course of the optimization efforts, the 1-(1H-tetrazol-5-yl)cyclopropane P1' substituent emerged as an improved alternative, offering increased metabolic stability and lower clearance, while maintaining excellent potency and selectivity.

NMR Fragment Screening Hit Induces Plasticity of BRD7/9 Bromodomains.

PubMed

Wang, Na; Li, Fudong; Bao, Hongyu; Li, Jie; Wu, Jihui; Ruan, Ke

2016-08-03

The complex biology associated with inhibition of bromodomain and extra-terminal (BET) domains by chemical probes has attracted increasing attention, and there is a need to identify non-BET bromodomain (BD) inhibitors. Several potent inhibitors of the BRD9 BD have recently been discovered, with anticancer and anti-inflammation activity. However, its paralogue, BRD7 BD, remains unexploited. Here, we identified new chemotypes targeting BRD7 BD by using NMR fragment-based screening. BRD7/9 BDs exhibit similar patterns of chemical-shift perturbation upon the titration of hit compound 1. The crystal structure revealed that 1 repels the Y222 group of BRD9 BD in a similar way to that for butyryllysine, but not acetyllysine and known inhibitors. Hit 1 induced less rearrangement of residue F161 of BRD9 BD than acetyllysine, butyryllysine, and crotonyllysine. Our study provides structural insight into a new generation of butyryllysine mimics for probing the function of BRD7/9 BD. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Discovery of 2-(1H-indol-5-ylamino)-6-(2,4-difluorophenylsulfonyl)-8-methylpyrido[2,3-d]pyrimidin-7(8H)-one (7ao) as a potent selective inhibitor of Polo like kinase 2 (PLK2)

PubMed Central

Reddy, M. V. Ramana; Akula, Balireddy; Jatiani, Shashidhar; Vasquez-Del Carpio, Rodrigo; Billa, Vinay K.; Mallireddigari, Muralidhar R.; Cosenza, Stephen C.; Subbaiah, D. R. C. Venkata; Bharathi, E. Vijaya; Pallela, Venkat R.; Ramkumar, Poornima; Jain, Rinku; Aggarwal, Aneel K.; Reddy, E. Premkumar

2018-01-01

Several families of protein kinases have been shown to play a critical role in the regulation of cell cycle progression, particularly progression through mitosis. These kinase families include the Aurora kinases, the Mps1 gene product and the Polo Like family of protein kinases (PLKs). The PLK family consists of five members and of these, the role of PLK1 in human cancer is well documented. PLK2 (SNK), which is highly homologous to PLK1, has been shown to play a critical role in centriole duplication and is also believed to play a regulatory role in the survival pathway by physically stabilizing the TSC1/2 complex in tumor cells under hypoxic conditions. As a part of our research program, we have developed a library of novel ATP mimetic chemotypes that are cytotoxic against a panel of cancer cell lines. We show that one of these chemotypes, the 6-arylsulfonyl pyridopyrimidinones, induces apoptosis of human tumor cell lines in nanomolar concentrations. The most potent of these compounds, 7ao, was found to be a highly specific inhibitor of PLK2 when profiled against a panel of 288 wild type, 55 mutant and 12 lipid kinases. Here, we describe the synthesis, structure activity relationship, in vitro kinase specificity and biological activity of the lead compound, 7ao. PMID:26762835

Discovery of 2-(1H-indol-5-ylamino)-6-(2,4-difluorophenylsulfonyl)-8-methylpyrido[2,3-d]pyrimidin-7(8H)-one (7ao) as a potent selective inhibitor of Polo like kinase 2 (PLK2).

PubMed

Reddy, M V Ramana; Akula, Balireddy; Jatiani, Shashidhar; Vasquez-Del Carpio, Rodrigo; Billa, Vinay K; Mallireddigari, Muralidhar R; Cosenza, Stephen C; Venkata Subbaiah, D R C; Bharathi, E Vijaya; Pallela, Venkat R; Ramkumar, Poornima; Jain, Rinku; Aggarwal, Aneel K; Reddy, E Premkumar

2016-02-15

Several families of protein kinases have been shown to play a critical role in the regulation of cell cycle progression, particularly progression through mitosis. These kinase families include the Aurora kinases, the Mps1 gene product and the Polo Like family of protein kinases (PLKs). The PLK family consists of five members and of these, the role of PLK1 in human cancer is well documented. PLK2 (SNK), which is highly homologous to PLK1, has been shown to play a critical role in centriole duplication and is also believed to play a regulatory role in the survival pathway by physically stabilizing the TSC1/2 complex in tumor cells under hypoxic conditions. As a part of our research program, we have developed a library of novel ATP mimetic chemotypes that are cytotoxic against a panel of cancer cell lines. We show that one of these chemotypes, the 6-arylsulfonyl pyridopyrimidinones, induces apoptosis of human tumor cell lines in nanomolar concentrations. The most potent of these compounds, 7ao, was found to be a highly specific inhibitor of PLK2 when profiled against a panel of 288 wild type, 55 mutant and 12 lipid kinases. Here, we describe the synthesis, structure activity relationship, in vitro kinase specificity and biological activity of the lead compound, 7ao. Copyright © 2015 Elsevier Ltd. All rights reserved.

Discovery of Indazoles as Potent, Orally Active Dual Neurokinin 1 Receptor Antagonists and Serotonin Transporter Inhibitors for the Treatment of Depression.

PubMed

Degnan, Andrew P; Tora, George O; Huang, Hong; Conlon, David A; Davis, Carl D; Hanumegowda, Umesh M; Hou, Xiaoping; Hsiao, Yi; Hu, Joanna; Krause, Rudolph; Li, Yu-Wen; Newton, Amy E; Pieschl, Rick L; Raybon, Joseph; Rosner, Thorsten; Sun, Jung-Hui; Taber, Matthew T; Taylor, Sarah J; Wong, Michael K; Zhang, Huiping; Lodge, Nicholas J; Bronson, Joanne J; Macor, John E; Gillman, Kevin W

2016-12-21

Combination studies of neurokinin 1 (NK1) receptor antagonists and serotonin-selective reuptake inhibitors (SSRIs) have shown promise in preclinical models of depression. Such a combination may offer important advantages over the current standard of care. Herein we describe the discovery and optimization of an indazole-based chemotype to provide a series of potent dual NK1 receptor antagonists/serotonin transporter (SERT) inhibitors to overcome issues of ion channel blockade. This effort culminated in the identification of compound 9, an analogue that demonstrated favorable oral bioavailability, excellent brain uptake, and robust in vivo efficacy in a validated depression model. Over the course of this work, a novel heterocycle-directed asymmetric hydrogenation was developed to facilitate installation of the key stereogenic center.

Falcipain inhibitors as potential therapeutics for resistant strains of malaria: a patent review.

PubMed

Mane, Uttam Rajaram; Gupta, Ramesh C; Nadkarni, Sunil Sadanand; Giridhar, Rajani R; Naik, Prashant Prakash; Yadav, Mange R

2013-02-01

There is an urgent need to discover new antimalarial drugs due to emergence of resistance in the parasite to the existing drugs. Malarial cysteine proteases falcipin-2 (FP-2) and falcipain-3 (FP-3) are attractive targets for antimalarial chemotherapy. The structures and functions of FP-2/3, their binding domains and their interactions with small- and macro-molecules are well studied. These studies could provide important insight into rational designing of FP inhibitors as potential antimalarial drugs. This review is focused on a selection of interesting patents published during 1999 - 2011 on peptidic and nonpeptidic chemotypes of the FP-2/FP-3 inhibitors. It is a known fact that malaria is a serious health problem worldwide due to the emergence of resistant strains. Hence, development of novel, potent and affordable antimalarial drugs devoid of side effects is of great significance and in great demand. FPs, the malarial cysteine proteases are potential targets for development of new antimalarial drugs. Assessing the available literature on FP-2/3 and their inhibitors it could be speculated that these inhibitors have the potential to enter the clinical stages of development for the treatment of malaria in the years to come.

Synthesis and biological evaluation of ranitidine analogs as multiple-target-directed cognitive enhancers for the treatment of Alzheimer's disease.

PubMed

Gao, Jie; Midde, Narasimha; Zhu, Jun; Terry, Alvin V; McInnes, Campbell; Chapman, James M

2016-11-15

Using molecular modeling and rationally designed structural modifications, the multi-target structure-activity relationship for a series of ranitidine analogs has been investigated. Incorporation of a variety of isosteric groups indicated that appropriate aromatic moieties provide optimal interactions with the hydrophobic and π-π interactions with the peripheral anionic site of the AChE active site. The SAR of a series of cyclic imides demonstrated that AChE inhibition is increased by additional aromatic rings, where 1,8-naphthalimide derivatives were the most potent analogs and other key determinants were revealed. In addition to improving AChE activity and chemical stability, structural modifications allowed determination of binding affinities and selectivities for M1-M4 receptors and butyrylcholinesterase (BuChE). These results as a whole indicate that the 4-nitropyridazine moiety of the JWS-USC-75IX parent ranitidine compound (JWS) can be replaced with other chemotypes while retaining effective AChE inhibition. These studies allowed investigation into multitargeted binding to key receptors and warrant further investigation into 1,8-naphthalimide ranitidine derivatives for the treatment of Alzheimer's disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

Discovery of novel InhA reductase inhibitors: application of pharmacophore- and shape-based screening approach.

PubMed

Kumar, Uday Chandra; Bvs, Suneel Kumar; Mahmood, Shaik; D, Sriram; Kumar-Sahu, Prashanta; Pulakanam, Sridevi; Ballell, Lluís; Alvarez-Gomez, Daniel; Malik, Siddharth; Jarp, Sarma

2013-03-01

InhA is a promising and attractive target in antimycobacterial drug development. InhA is involved in the reduction of long-chain trans-2-enoyl-ACP in the type II fatty acid biosynthesis pathway of Mycobacterium tuberculosis. Recent studies have demonstrated that InhA is one of the targets for the second line antitubercular drug ethionamide. In the current study, we have generated quantitative pharmacophore models using known InhA inhibitors and validated using a large test set. The validated pharmacophore model was used as a query to screen an in-house database of 400,000 compounds and retrieved 25,000 hits. These hits were further ranked based on its shape and feature similarity with potent InhA inhibitor using rapid overlay of chemical structures (OpenEye™) and subsequent hits were subjected for docking. Based on the pharmacophore, rapid overlay of chemical structures model and docking interactions, 32 compounds with more than eight chemotypes were selected, purchased and assayed for InhA inhibitory activity. Out of the 32 compounds, 28 demonstrated 10-38% inhibition against InhA at 10 µM. Further optimization of these analogues is in progress and will update in due course.

High-performance Thin-layer Chromatographic-densitometric Quantification and Recovery of Bioactive Compounds for Identification of Elite Chemotypes of Gloriosa superba L. Collected from Sikkim Himalayas (India)

PubMed Central

Misra, Ankita; Shukla, Pushpendra Kumar; Kumar, Bhanu; Chand, Jai; Kushwaha, Poonam; Khalid, Md.; Singh Rawat, Ajay Kumar; Srivastava, Sharad

2017-01-01

Background: Gloriosa superba L. (Colchicaceae) is used as adjuvant therapy in gout for its potential antimitotic activity due to high colchicine(s) alkaloids. Objective: This study aimed to develop an easy, cheap, precise, and accurate high-performance thin-layer chromatographic (HPTLC) validated method for simultaneous quantification of bioactive alkaloids (colchicine and gloriosine) in G. superba L. and to identify its elite chemotype(s) from Sikkim Himalayas (India). Methods: The HPTLC chromatographic method was developed using mobile phase of chloroform: acetone: diethyl amine (5:4:1) at λmax of 350 nm. Results: Five germplasms were collected from targeted region, and on morpho-anatomical inspection, no significant variation was observed among them. Quantification data reveal that content of colchicine (Rf: 0.72) and gloriosine (Rf: 0.61) varies from 0.035%–0.150% to 0.006%–0.032% (dry wt. basis). Linearity of method was obtained in the concentration range of 100–400 ng/spot of marker(s), exhibiting regression coefficient of 0.9987 (colchicine) and 0.9983 (gloriosine) with optimum recovery of 97.79 ± 3.86 and 100.023% ± 0.01%, respectively. Limit of detection and limit of quantification were analyzed, respectively, as 6.245, 18.926 and 8.024, 24.316 (ng). Two germplasms, namely NBG-27 and NBG-26, were found to be elite chemotype of both the markers. Conclusion: The developed method is validated in terms of accuracy, recovery, and precision studies as per the ICH guidelines (2005) and can be adopted for the simultaneous quantification of colchicine and gloriosine in phytopharmaceuticals. In addition, this study is relevant to explore the chemotypic variability in metabolite content for commercial and medicinal purposes. SUMMARY An easy, cheap, precise, and accurate high performance thin layer chromatographic (HPTLC) validated method for simultaneous quantification of bioactive alkaloids (colchicine and gloriosine) in G. superba L.Five germplasms were collected from targeted region, and on morpho anatomical inspection, no significant variation was observed among themQuantification data reveal that content of colchicine (Rf: 0.72) and gloriosine (Rf: 0.61) varies from 0.035%–0.150% to 0.006%–0.032% (dry wt. basis)Two germplasms, namely NBG 27 and NBG 26, were found to be elite chemotype of both the markers. PMID:29142436

High-performance Thin-layer Chromatographic-densitometric Quantification and Recovery of Bioactive Compounds for Identification of Elite Chemotypes of Gloriosa superba L. Collected from Sikkim Himalayas (India).

PubMed

Misra, Ankita; Shukla, Pushpendra Kumar; Kumar, Bhanu; Chand, Jai; Kushwaha, Poonam; Khalid, Md; Singh Rawat, Ajay Kumar; Srivastava, Sharad

2017-10-01

Gloriosa superba L. (Colchicaceae) is used as adjuvant therapy in gout for its potential antimitotic activity due to high colchicine(s) alkaloids. This study aimed to develop an easy, cheap, precise, and accurate high-performance thin-layer chromatographic (HPTLC) validated method for simultaneous quantification of bioactive alkaloids (colchicine and gloriosine) in G. superba L. and to identify its elite chemotype(s) from Sikkim Himalayas (India). The HPTLC chromatographic method was developed using mobile phase of chloroform: acetone: diethyl amine (5:4:1) at λ max of 350 nm. Five germplasms were collected from targeted region, and on morpho-anatomical inspection, no significant variation was observed among them. Quantification data reveal that content of colchicine ( R f : 0.72) and gloriosine ( R f : 0.61) varies from 0.035%-0.150% to 0.006%-0.032% (dry wt. basis). Linearity of method was obtained in the concentration range of 100-400 ng/spot of marker(s), exhibiting regression coefficient of 0.9987 (colchicine) and 0.9983 (gloriosine) with optimum recovery of 97.79 ± 3.86 and 100.023% ± 0.01%, respectively. Limit of detection and limit of quantification were analyzed, respectively, as 6.245, 18.926 and 8.024, 24.316 (ng). Two germplasms, namely NBG-27 and NBG-26, were found to be elite chemotype of both the markers. The developed method is validated in terms of accuracy, recovery, and precision studies as per the ICH guidelines (2005) and can be adopted for the simultaneous quantification of colchicine and gloriosine in phytopharmaceuticals. In addition, this study is relevant to explore the chemotypic variability in metabolite content for commercial and medicinal purposes. An easy, cheap, precise, and accurate high performance thin layer chromatographic (HPTLC) validated method for simultaneous quantification of bioactive alkaloids (colchicine and gloriosine) in G. superba L.Five germplasms were collected from targeted region, and on morpho anatomical inspection, no significant variation was observed among themQuantification data reveal that content of colchicine (Rf: 0.72) and gloriosine (Rf: 0.61) varies from 0.035%-0.150% to 0.006%-0.032% (dry wt. basis)Two germplasms, namely NBG 27 and NBG 26, were found to be elite chemotype of both the markers.

Identification of Chemical Features Linked to Thyroperoxidase ...

EPA Pesticide Factsheets

Disruption of maternal serum thyroid hormone (TH) adversely affects fetal neurodevelopment. Therefore, assay development within the US EPA ToxCast program is ongoing to enable screening for chemicals that may disrupt TH, in support of the Endocrine Disruption Screening Program (EDSP21). The AUR-TPO assay was recently developed to screen >1,000 ToxCast chemicals for potential thyroperoxidase (TPO) inhibition activity. TPO is critical for TH synthesis and is a known target of thyroid-disrupting chemicals. The bioactivity results from the AUR-TPO assay were used to identify chemical substructures associated with in vitro TPO inhibition. Substructure profiles were generated for each chemical in the ToxCast test set using the publicly-available ToxPrint 2.0 chemotypes. Chemotypes enriched among the putative TPO inhibitors were identified using a cumulative hypergeometric probability (p < 0.01). Of the total 729 chemotypes evaluated, 31 were overrepresented among TPO inhibitors. Examination of those 31 chemotypes revealed four basic pharmacophores that accounted for 70% of the ToxCast chemicals active in the AUR-TPO assay: aromatic alcohols, aromatic amines, thiocarbonyls and phosphothioates. Chemico-structural analysis of AUR-TPO screening results enabled the identification of chemical features that likely drive TPO inhibition in the AUR-TPO assay. This highlights the potential to identify thyroid-disrupting chemicals in silico using structural alerts identified by

PAINS in the Assay: Chemical Mechanisms of Assay Interference and Promiscuous Enzymatic Inhibition Observed during a Sulfhydryl-Scavenging HTS

PubMed Central

2015-01-01

Significant resources in early drug discovery are spent unknowingly pursuing artifacts and promiscuous bioactive compounds, while understanding the chemical basis for these adverse behaviors often goes unexplored in pursuit of lead compounds. Nearly all the hits from our recent sulfhydryl-scavenging high-throughput screen (HTS) targeting the histone acetyltransferase Rtt109 were such compounds. Herein, we characterize the chemical basis for assay interference and promiscuous enzymatic inhibition for several prominent chemotypes identified by this HTS, including some pan-assay interference compounds (PAINS). Protein mass spectrometry and ALARM NMR confirmed these compounds react covalently with cysteines on multiple proteins. Unfortunately, compounds containing these chemotypes have been published as screening actives in reputable journals and even touted as chemical probes or preclinical candidates. Our detailed characterization and identification of such thiol-reactive chemotypes should accelerate triage of nuisance compounds, guide screening library design, and prevent follow-up on undesirable chemical matter. PMID:25634295

Large-Scale Chemical Similarity Networks for Target Profiling of Compounds Identified in Cell-Based Chemical Screens

PubMed Central

Lo, Yu-Chen; Senese, Silvia; Li, Chien-Ming; Hu, Qiyang; Huang, Yong; Damoiseaux, Robert; Torres, Jorge Z.

2015-01-01

Target identification is one of the most critical steps following cell-based phenotypic chemical screens aimed at identifying compounds with potential uses in cell biology and for developing novel disease therapies. Current in silico target identification methods, including chemical similarity database searches, are limited to single or sequential ligand analysis that have limited capabilities for accurate deconvolution of a large number of compounds with diverse chemical structures. Here, we present CSNAP (Chemical Similarity Network Analysis Pulldown), a new computational target identification method that utilizes chemical similarity networks for large-scale chemotype (consensus chemical pattern) recognition and drug target profiling. Our benchmark study showed that CSNAP can achieve an overall higher accuracy (>80%) of target prediction with respect to representative chemotypes in large (>200) compound sets, in comparison to the SEA approach (60–70%). Additionally, CSNAP is capable of integrating with biological knowledge-based databases (Uniprot, GO) and high-throughput biology platforms (proteomic, genetic, etc) for system-wise drug target validation. To demonstrate the utility of the CSNAP approach, we combined CSNAP's target prediction with experimental ligand evaluation to identify the major mitotic targets of hit compounds from a cell-based chemical screen and we highlight novel compounds targeting microtubules, an important cancer therapeutic target. The CSNAP method is freely available and can be accessed from the CSNAP web server (http://services.mbi.ucla.edu/CSNAP/). PMID:25826798

Molecular and phenotypic descriptions of Stachybotrys chlorohalonata sp. nov. and two chemotypes of Stachybotrys chartarum found in water-damaged buildings.

PubMed

Andersen, Birgitte; Nielsen, Kristian F; Thrane, Ulf; Szaro, Tim; Taylor, John W; Jarvis, Bruce B

2003-01-01

Twenty-five Stachybotrys isolates from two previous studies have been examined and compared, using morphological, chemical and phylogenetic methods. The results show that S. chartarum sensu lato can be segregated into two chemotypes and one new species. The new species, S. chlorohalonata, differs morphologically from S. chartarum by having smooth conidia, being more restricted in growth and producing a green extracellular pigment on the medium CYA. S. chlorohalonata and S. chartarum also have different tri5, chs1 and tub1 gene fragment sequences. The two chemotypes of S. chartarum, chemotype S and chemotype A, have similar morphology but differ in production of metabolites. Chemotype S produces macrocyclic trichothecenes, satratoxins and roridins, while chemotype A produces atranones and dolabellanes. There is no difference between the two chemotypes in the tub1 gene fragment, but there is a one nucleotide difference in each of the tri5 and the chs1 gene fragments.

Genetic Relationships among Different Chemotypes of Lupinus sulphureus.

PubMed

Cook, Daniel; Mott, Ivan W; Larson, Steven R; Lee, Stephen T; Johnson, Robert; Stonecipher, Clinton A

2018-02-28

Lupines (Lupinus spp.) are a common plant legume species found on western U.S. rangelands. Lupinus spp. may contain quinolizidine and/or piperidine alkaloids that can be toxic and/or teratogenic to grazing livestock. Alkaloid profiles may vary between and within a species. The objectives of this study were to (1) further explore the characteristic alkaloid profiles of Lupinus sulphureus using field collections and (2) explore the phylogenetic relationship of the different populations and chemotypes of L. sulphureus using the amplified fragment length polymorphism method of DNA fingerprinting, thus providing possible explanations to the phenomena of multiple chemotypes within a species. A total of 49 accessions of L. sulphureus were classified into seven chemotypes. The DNA profiles showed that one L. sulphureus chemotype, chemotype A, is genetically divergent from the other chemotypes of L. sulphureus, suggesting that it represents an unresolved lupine taxon, possibly a new lupine species. Additionally, the different chemotypes of L. sulphureus represented different genetic groups, as shown by Bayesian cluster analysis and principle component analysis.

Discovery of N-[2-[2-[[3-methoxy-4-(5-oxazolyl)phenyl]amino]-5-oxazolyl]phenyl]-N-methyl-4- morpholineacetamide as a novel and potent inhibitor of inosine monophosphate dehydrogenase with excellent in vivo activity.

PubMed

Dhar, T G Murali; Shen, Zhongqi; Guo, Junqing; Liu, Chunjian; Watterson, Scott H; Gu, Henry H; Pitts, William J; Fleener, Catherine A; Rouleau, Katherine A; Sherbina, N Z; McIntyre, Kim W; Shuster, David J; Witmer, Mark R; Tredup, Jeffrey A; Chen, Bang-Chi; Zhao, Rulin; Bednarz, Mark S; Cheney, Daniel L; MacMaster, John F; Miller, Laura M; Berry, Karen K; Harper, Timothy W; Barrish, Joel C; Hollenbaugh, Diane L; Iwanowicz, Edwin J

2002-05-23

Inosine monophosphate dehydrogenase (IMPDH) is a key enzyme that is involved in the de novo synthesis of purine nucleotides. Novel 2-aminooxazoles were synthesized and tested for inhibition of IMPDH catalytic activity. Multiple analogues based on this chemotype were found to inhibit IMPDH with low nanomolar potency. One of the analogues (compound 23) showed excellent in vivo activity in the inhibition of antibody production in mice and in the adjuvant induced arthritis model in rats.

Discovery and characterization of NVP-QAV680, a potent and selective CRTh2 receptor antagonist suitable for clinical testing in allergic diseases.

PubMed

Sandham, David A; Arnold, Nicola; Aschauer, Heinrich; Bala, Kamlesh; Barker, Lucy; Brown, Lyndon; Brown, Zarin; Budd, David; Cox, Brian; Docx, Cerys; Dubois, Gerald; Duggan, Nicholas; England, Karen; Everatt, Brian; Furegati, Marcus; Hall, Edward; Kalthoff, Frank; King, Anna; Leblanc, Catherine J; Manini, Jodie; Meingassner, Josef; Profit, Rachael; Schmidt, Alfred; Simmons, Jennifer; Sohal, Bindi; Stringer, Rowan; Thomas, Matthew; Turner, Katharine L; Walker, Christoph; Watson, Simon J; Westwick, John; Willis, Jennifer; Williams, Gareth; Wilson, Caroline

2013-11-01

Optimization of a 7-azaindole-3-acetic acid CRTh2 receptor antagonist chemotype derived from high throughput screening furnished a highly selective compound NVP-QAV680 with low nM functional potency for inhibition of CRTh2 driven human eosinophil and Th2 lymphocyte activation in vitro. The molecule exhibited good oral bioavailability in the rat, combined with efficacy in rodent CRTh2-dependent mechanistic and allergic disease models and was suitable for clinical development. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evolution of the Cannabinoid and Terpene Content during the Growth of Cannabis sativa Plants from Different Chemotypes.

PubMed

Aizpurua-Olaizola, Oier; Soydaner, Umut; Öztürk, Ekin; Schibano, Daniele; Simsir, Yilmaz; Navarro, Patricia; Etxebarria, Nestor; Usobiaga, Aresatz

2016-02-26

The evolution of major cannabinoids and terpenes during the growth of Cannabis sativa plants was studied. In this work, seven different plants were selected: three each from chemotypes I and III and one from chemotype II. Fifty clones of each mother plant were grown indoors under controlled conditions. Every week, three plants from each variety were cut and dried, and the leaves and flowers were analyzed separately. Eight major cannabinoids were analyzed via HPLC-DAD, and 28 terpenes were quantified using GC-FID and verified via GC-MS. The chemotypes of the plants, as defined by the tetrahydrocannabinolic acid/cannabidiolic acid (THCA/CBDA) ratio, were clear from the beginning and stable during growth. The concentrations of the major cannabinoids and terpenes were determined, and different patterns were found among the chemotypes. In particular, the plants from chemotypes II and III needed more time to reach peak production of THCA, CBDA, and monoterpenes. Differences in the cannabigerolic acid development among the different chemotypes and between monoterpene and sesquiterpene evolution patterns were also observed. Plants of different chemotypes were clearly differentiated by their terpene content, and characteristic terpenes of each chemotype were identified.

Fragment Based Optimization of Metabotropic Glutamate Receptor 2 (mGluR2) Positive Allosteric Modulators in the Absence of Structural Information.

PubMed

Szabó, György; Túrós, György I; Kolok, Sándor; Vastag, Mónika; Sánta, Zsuzsanna; Dékány, Miklós; Lévay, György I; Greiner, István; Natsumi, Minami; Tatsuya, Watanabe; Keserű, György M

2018-03-14

Metabotropic glutamate receptor 2 (mGluR2) positive allosteric modulators (PAMs) have been implicated as potential pharmacotherapy for psychiatric conditions. Screening our corporate compound deck, we identified a benzotriazole fragment (4) that was rapidly optimized to a potent and metabolically stable early lead (16). The highly lipophilic character of 16, together with its limited solubility, permeability, and high protein binding, however, did not allow reaching of the proof of concept in vivo. Since further attempts on the optimization of druglike properties were unsuccessful, the original hit 4 has been revisited and was optimized following the principles of fragment based drug discovery (FBDD). Lacking structural information on the receptor-ligand complex, we implemented a group efficiency (GE) based strategy and identified a new fragment like lead (60) with more balanced profile. Significant improvement achieved on the druglike properties nominated the compound for in vivo proof of concept studies that revealed the chemotype being a promising PAM lead targeting mGluR2 receptors.

Chemotypes of Pistacia atlantica leaf essential oils from Algeria.

PubMed

Gourine, Nadhir; Bombarda, Isabelle; Yousfi, Mohamed; Gaydou, Emile M

2010-01-01

The essential oils obtained by hydrodistillation of Pistacia atlantica Desf. leaves collected from different regions of Algeria were analyzed by GC and GC-MS. The essential oil was rich in monoterpenes and oxygenated sesquiterpenes. The major components were alpha-pinene (0.0-67%), delta-3-carene (0.0-56%), spathulenol (0.5-22%), camphene (0.0-21%), terpinen-4-ol (0.0-16%) and beta-pinene (0.0-13%). Among the various components identified, twenty were used for statistical analyses. The result of principal component analysis (PCA) showed the occurrence of three chemotypes: a delta-3-carene chemotype (16.4-56.2%), a terpinen-4-ol chemotype (10.8-16.0%) and an alpha-pinene/camphene chemotype (10.9-66.6%/3.8-20.9%). It was found that the essential oil from female plants (delta-3-carene chemotype) could be easily differentiated from the two other chemotypes corresponding to male trees.

Administering multiple doses of a non N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-containing tall larkspur (Delphinium occidentale) to cattle

USDA-ARS?s Scientific Manuscript database

Larkspurs (Delphinium spp.) are a serious toxic plant problem for cattle in western North America. There are two chemotypes in the tall larkspur Delphinium occidentale, a more toxic chemotype and a less toxic chemotype. These chemotypes differ in the composition and concentrations of key alkaloids. ...

Histone lysine methyltransferase structure activity relationships that allow for segregation of G9a inhibition and anti-Plasmodium activity† †The authors declare no competing interests. ‡ ‡Electronic supplementary information (ESI) available: Supplementary Tables ST1–ST5, experimental data for the representative diaminoquinazoline analogues, 2D NMRs of 85 and 111a and X-ray structure of 111a (Fig. SF1). The coordinates for 111a have been deposited with CCDC 1503377. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7md00052a

PubMed Central

Sundriyal, Sandeep; Chen, Patty B.; Lubin, Alexandra S.; Lueg, Gregor A.; Li, Fengling; White, Andrew J. P.; Malmquist, Nicholas A.; Vedadi, Masoud; Scherf, Artur

2017-01-01

Plasmodium falciparum HKMTs (PfHKMTs) play a key role in controlling Plasmodium gene expression and represent exciting new anti-malarial epigenetic targets. Using an inhibitor series derived from the diaminoquinazoline HKMT inhibitory chemotype, we have previously identified compounds with highly promising antimalarial activity, including irreversible asexual cycle blood stage-independent cytotoxic activity at nM concentrations, oral efficacy in in vivo models of disease, and the unprecedented ability to reactivate dormant liver stage parasites (hypnozoites). However, future development of this series will need to address host versus parasite selectivity, where inhibitory activity against human G9a is removed from the lead compounds, while maintaining potent anti-Plasmodium activity. Herein, we report an extensive study of the SAR of this series against both G9a and P. falciparum. We have identified key SAR features which demonstrate that high parasite vs. G9a selectivity can be achieved by selecting appropriate substituents at position 2, 4 and 7 of the quinazoline ring. We have also, in turn, discovered that potent G9a inhibitors can be identified by employing a 6-carbon ‘Nle mimic’ at position 7. Together, this data suggests that while broadly similar, the G9a and potential PfHKMT target(s) binding pockets and/or binding modes of the diaminoquinazoline analogues exhibit clear and exploitable differences. Based on this, we believe this scaffold to have clear potential for development into a novel anti-malarial therapeutic. PMID:29308121

Yield and oil composition of 38 basil (Ocimum basilicum L.) accessions grown in Mississippi.

PubMed

Zheljazkov, Valtcho D; Callahan, Amber; Cantrell, Charles L

2008-01-09

A field experiment was conducted to assess yield, oil content, and composition of 38 genotypes of sweet basil ( Ocimum basilicum L.). Overall, biomass yields were high and comparable to those reported in the literature. However, basil genotypes differed significantly with respect to oil content and composition. Oil content of the tested accessions varied from 0.07% to 1.92% in dry herbage. On the basis of the oil composition, basil accessions were divided into seven groups: (1) high-linalool chemotype [19-73% (-)-linalool], (2) linalool-eugenol chemotype [six chemotypes with 28-66% (-)-linalool and 5-29% eugenol], (3) methyl chavicol chemotype [six accessions with 20-72% methyl chavicol and no (-)-linalool], (4) methyl chavicol-linalool chemotype [six accessions with 8-29% methyl chavicol and 8-53% (-)-linalool], (5) methyl eugenol-linalool chemotype [two accessions with 37% and 91% methyl eugenol and 60% and 15% (-)-linalool], (6) methyl cinnamate-linalool chemotype [one accession with 9.7% methyl cinnamate and 31% (-)-linalool], and (7) bergamotene chemotype [one accession with bergamotene as major constituent, 5% eucalyptol, and <1% (-)-linalool]. Our results demonstrated that basil could be a viable essential oil crop in Mississippi. The availability of various chemotypes offers the opportunity for production of basil to meet the market requirements of specific basil oils or individual compounds such as (-)-linalool, eugenol, methyl chavicol, methyl cinnamate, or methyl eugenol.

Antimalarial activity of compounds comprising a primary benzene sulfonamide fragment.

PubMed

Andrews, Katherine T; Fisher, Gillian M; Sumanadasa, Subathdrage D M; Skinner-Adams, Tina; Moeker, Janina; Lopez, Marie; Poulsen, Sally-Ann

2013-11-15

Despite the urgent need for effective antimalarial drugs with novel modes of action no new chemical class of antimalarial drug has been approved for use since 1996. To address this, we have used a rational approach to investigate compounds comprising the primary benzene sulfonamide fragment as a potential new antimalarial chemotype. We report the in vitro activity against Plasmodium falciparum drug sensitive (3D7) and resistant (Dd2) parasites for a panel of fourteen primary benzene sulfonamide compounds. Our findings provide a platform to support the further evaluation of primary benzene sulfonamides as a new antimalarial chemotype, including the identification of the target of these compounds in the parasite. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Chemotaxonomy of Common Sage (Salvia officinalis) Based on the Volatile Constituents.

PubMed

Craft, Jonathan D; Satyal, Prabodh; Setzer, William N

2017-06-29

Background: Common sage ( Salvia officinalis ) is a popular culinary and medicinal herb. A literature survey has revealed that sage oils can vary widely in their chemical compositions. The purpose of this study was to examine sage essential oil from different sources/origins and to define the possible chemotypes of sage oil. Methods: Three different samples of sage leaf essential oil have been obtained and analyzed by GC-MS and GC-FID. A hierarchical cluster analysis was carried out on 185 sage oil compositions reported in the literature as well as the three samples in this study. Results: The major components of the three sage oils were the oxygenated monoterpenoids α-thujone (17.2-27.4%), 1,8-cineole (11.9-26.9%), and camphor (12.8-21.4%). The cluster analysis revealed five major chemotypes of sage oil, with the most common being a α-thujone > camphor > 1,8-cineole chemotype, of which the three samples in this study belong. The other chemotypes are an α-humulene-rich chemotype, a β-thujone-rich chemotype, a 1,8-cineole/camphor chemotype, and a sclareol/α-thujone chemotype. Conclusions: Most sage oils belonged to the "typical", α-thujone > camphor > 1,8-cineole, chemotype, but the essential oil compositions do vary widely and may have a profound effect on flavor and fragrance profiles as well as biological activities. There are currently no studies correlating sage oil composition with fragrance descriptions or with biological activities.

Identifying the preferred RNA motifs and chemotypes that interact by probing millions of combinations.

PubMed

Tran, Tuan; Disney, Matthew D

2012-01-01

RNA is an important therapeutic target but information about RNA-ligand interactions is limited. Here, we report a screening method that probes over 3,000,000 combinations of RNA motif-small molecule interactions to identify the privileged RNA structures and chemical spaces that interact. Specifically, a small molecule library biased for binding RNA was probed for binding to over 70,000 unique RNA motifs in a high throughput solution-based screen. The RNA motifs that specifically bind each small molecule were identified by microarray-based selection. In this library-versus-library or multidimensional combinatorial screening approach, hairpin loops (among a variety of RNA motifs) were the preferred RNA motif space that binds small molecules. Furthermore, it was shown that indole, 2-phenyl indole, 2-phenyl benzimidazole and pyridinium chemotypes allow for specific recognition of RNA motifs. As targeting RNA with small molecules is an extremely challenging area, these studies provide new information on RNA-ligand interactions that has many potential uses.

Identifying the Preferred RNA Motifs and Chemotypes that Interact by Probing Millions of Combinations

PubMed Central

Tran, Tuan; Disney, Matthew D.

2012-01-01

RNA is an important therapeutic target but information about RNA-ligand interactions is limited. Here we report a screening method that probes over 3,000,000 combinations of RNA motif-small molecule interactions to identify the privileged RNA structures and chemical spaces that interact. Specifically, a small molecule library biased for binding RNA was probed for binding to over 70,000 unique RNA motifs in a high throughput solution-based screen. The RNA motifs that specifically bind each small molecule were identified by microarray-based selection. In this library-versus-library or multidimensional combinatorial screening approach, hairpin loops (amongst a variety of RNA motifs) were the preferred RNA motif space that binds small molecules. Furthermore, it was shown that indole, 2-phenyl indole, 2-phenyl benzimidazole, and pyridinium chemotypes allow for specific recognition of RNA motifs. Since targeting RNA with small molecules is an extremely challenging area, these studies provide new information on RNA-ligand interactions that has many potential uses. PMID:23047683

Identification of a Bis-guanylhydrazone [4,4'-Diacetyldiphenylurea-bis(guanylhydrazone); NSC 109555] as a novel chemotype for inhibition of Chk2 kinase.

PubMed

Jobson, Andrew G; Cardellina, John H; Scudiero, Dominic; Kondapaka, Sudhir; Zhang, Hongliang; Kim, Hijoo; Shoemaker, Robert; Pommier, Yves

2007-10-01

Chk2 is a protein kinase involved in the ATM-dependent checkpoint pathway (http://discover.nci.nih.gov/mim). This pathway is activated by genomic instability and DNA damage and results in either cell cycle arrest, to allow DNA repair to occur, or cell death (apoptosis). Chk2 is activated by ATM-mediated phosphorylation and autophosphorylation and in turn phosphorylates its downstream targets (Cdc25A, Cdc25C, BRCA1, p53, Hdmx, E2F1, PP2A, and PML). Inhibition of Chk2 has been proposed to sensitize p53-deficient cells as well as protect normal tissue after exposure to DNA-damaging agents. We have developed a drug-screening program for specific Chk2 inhibitors using a fluorescence polarization assay, immobilized metal ion affinity-based fluorescence polarization (IMAP). This assay detects the degree of phosphorylation of a fluorescently linked substrate by Chk2. From a screen of over 100,000 compounds from the NCI Developmental Therapeutics Program, we identified a bis-guanylhydrazone [4,4'-diacetyldiphenylureabis(guanylhydrazone); NSC 109555] as a lead compound. In vitro data show the specific inhibition of Chk2 kinase activity by NSC 109555 using in vitro kinase assays and kinase-profiling experiments. NSC 109555 was shown to be a competitive inhibitor of Chk2 with respect to ATP, which was supported by docking of NSC 109555 into the ATP binding pocket of the Chk2 catalytic domain. The potency of NSC 109555 was comparable with that of other known Chk2 inhibitors, such as debromohymenialdisine and 2-arylbenzimidazole. These data define a novel chemotype for the development of potent and selective inhibitors of Chk2. This class of drugs may ultimately be useful in combination with current DNA-damaging agents used in the clinic.

Pharmacophore modeling and virtual screening studies to design some potential histone deacetylase inhibitors as new leads.

PubMed

Vadivelan, S; Sinha, B N; Rambabu, G; Boppana, Kiran; Jagarlapudi, Sarma A R P

2008-02-01

Histone deacetylase is one of the important targets in the treatment of solid tumors and hematological cancers. A total of 20 well-defined inhibitors were used to generate Pharmacophore models using and HypoGen module of Catalyst. These 20 molecules broadly represent 3 different chemotypes. The best HypoGen model consists of four-pharmacophore features--one hydrogen bond acceptor, one hydrophobic aliphatic and two ring aromatic centers. This model was validated against 378 known HDAC inhibitors with a correlation of 0.897 as well as enrichment factor of 2.68 against a maximum value of 3. This model was further used to retrieve molecules from NCI database with 238,819 molecules. A total of 4638 molecules from a pool of 238,819 molecules were identified as hits while 297 molecules were indicated as highly active. Also, a Similarity analysis has been carried out for set of 4638 hits with respect to most active molecule of each chemotypes which validated not only the Virtual Screening potential of the model but also identified the possible new Chemotypes. This type of Similarity analysis would prove to be efficient not only for lead generation but also for lead optimization.

Essential Oil Characterization of Thymus vulgaris from Various Geographical Locations

PubMed Central

Satyal, Prabodh; Murray, Brittney L.; McFeeters, Robert L.; Setzer, William N.

2016-01-01

Thyme (Thymus vulgaris L.) is a commonly used flavoring agent and medicinal herb. Several chemotypes of thyme, based on essential oil compositions, have been established, including (1) linalool; (2) borneol; (3) geraniol; (4) sabinene hydrate; (5) thymol; (6) carvacrol, as well as a number of multiple-component chemotypes. In this work, two different T. vulgaris essential oils were obtained from France and two were obtained from Serbia. The chemical compositions were determined using gas chromatography–mass spectrometry. In addition, chiral gas chromatography was used to determine the enantiomeric compositions of several monoterpenoid components. The T. vulgaris oil from Nyons, France was of the linalool chemotype (linalool, 76.2%; linalyl acetate, 14.3%); the oil sample from Jablanicki, Serbia was of the geraniol chemotype (geraniol, 59.8%; geranyl acetate, 16.7%); the sample from Pomoravje District, Serbia was of the sabinene hydrate chemotype (cis-sabinene hydrate, 30.8%; trans-sabinene hydrate, 5.0%); and the essential oil from Richerenches, France was of the thymol chemotype (thymol, 47.1%; p-cymene, 20.1%). A cluster analysis based on the compositions of these essential oils as well as 81 additional T. vulgaris essential oils reported in the literature revealed 20 different chemotypes. This work represents the first chiral analysis of T. vulgaris monoterpenoids and a comprehensive description of the different chemotypes of T. vulgaris. PMID:28231164

Synergism of virtual screening and medicinal chemistry: identification and optimization of allosteric antagonists of metabotropic glutamate receptor 1.

PubMed

Noeske, Tobias; Trifanova, Dina; Kauss, Valerjans; Renner, Steffen; Parsons, Christopher G; Schneider, Gisbert; Weil, Tanja

2009-08-01

We report the identification of novel potent and selective metabotropic glutamate receptor 1 (mGluR1) antagonists by virtual screening and subsequent hit optimization. For ligand-based virtual screening, molecules were represented by a topological pharmacophore descriptor (CATS-2D) and clustered by a self-organizing map (SOM). The most promising compounds were tested in mGluR1 functional and binding assays. We identified a potent chemotype exhibiting selective antagonistic activity at mGluR1 (functional IC(50)=0.74+/-0.29 microM). Hit optimization yielded lead structure 16 with an affinity of K(i)=0.024+/-0.001 microM and greater than 1000-fold selectivity for mGluR1 versus mGluR5. Homology-based receptor modelling suggests a binding site compatible with previously reported mutation studies. Our study demonstrates the usefulness of ligand-based virtual screening for scaffold-hopping and rapid lead structure identification in early drug discovery projects.

Design and Development of Stable, Water-soluble, Human Toll-like Receptor 2-Specific, Monoacyl Lipopeptides as Candidate Vaccine Adjuvants

PubMed Central

Salunke, Deepak B.; Connelly, Seth W.; Shukla, Nikunj M.; Hermanson, Alec R.; Fox, Lauren M.; David, Sunil A.

2013-01-01

Antigens in modern subunit vaccines are largely soluble and poorly immunogenic proteins inducing relatively short-lived immune responses. Appropriate adjuvants initiate early innate immune responses, amplifying subsequent adaptive immune responses. Agonists of TLR2 are devoid of significant pro-inflammatory activity in ex vivo human blood models, and yet potently adjuvantic, suggesting that this chemotype may be a safe and effective adjuvant. Our earlier work on the monoacyl lipopeptide class of TLR2 agonists led to the design of a highly potent lead, but with negligible aqueous solubility, necessitating the reintroduction of aqueous solubility. We explored several strategies of introducing ionizable groups on the lipopeptide, as well as the systematic evaluation of chemically stable bioisosteres of the ester-linked palmitoyl group. These studies have led to a fully optimized, chemically stable, and highly water-soluble, human TLR2-specific agonist, which was found to have an excellent safety profile and displayed prominent adjuvantic activities in rabbit models. PMID:23795818

6-(1-Benzyl-1H-pyrrol-2-yl)-2,4-dioxo-5-hexenoic acids as dual inhibitors of recombinant HIV-1 integrase and ribonuclease H, synthesized by a parallel synthesis approach.

PubMed

Costi, Roberta; Métifiot, Mathieu; Esposito, Francesca; Cuzzucoli Crucitti, Giuliana; Pescatori, Luca; Messore, Antonella; Scipione, Luigi; Tortorella, Silvano; Zinzula, Luca; Novellino, Ettore; Pommier, Yves; Tramontano, Enzo; Marchand, Christophe; Di Santo, Roberto

2013-11-14

The increasing efficiency of HAART has helped to transform HIV/AIDS into a chronic disease. Still, resistance and drug-drug interactions warrant the development of new anti-HIV agents. We previously discovered hit 6, active against HIV-1 replication and targeting RNase H in vitro. Because of its diketo-acid moiety, we speculated that this chemotype could serve to develop dual inhibitors of both RNase H and integrase. Here, we describe a new series of 1-benzyl-pyrrolyl diketohexenoic derivatives, 7a-y and 8a-y, synthesized following a parallel solution-phase approach. Those 50 analogues have been tested on recombinant enzymes (RNase H and integrase) and in cell-based assays. Approximately half (22) exibited inhibition of HIV replication. Compounds 7b, 7u, and 8g were the most active against the RNase H activity of reverse-transcriptase, with IC50 values of 3, 3, and 2.5 μM, respectively. Compound 8g was also the most potent integrase inhibitor with an IC50 value of 26 nM.

Administering multiple doses of a non N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-containing tall larkspur (Delphinium occidentale) to cattle.

PubMed

Welch, K D; Stonecipher, C A; Green, B T; Gardner, D R; Cook, D; Pfister, J A

2017-03-15

Larkspurs (Delphinium spp.) are a serious toxic plant problem for cattle in western North America. There are two chemotypes of D. occidentale, a more toxic and a less toxic chemotype. The objective of this study was to evaluate the acute toxicity of the less toxic chemotype when administered in multiple doses to cattle. These results suggest that cattle could consume enough of the less toxic chemotype to be poisoned in a range setting. Published by Elsevier Ltd.

Development of a Generic PCR Detection of 3-Acetyldeoxy-nivalenol-, 15-Acetyldeoxynivalenol- and Nivalenol-Chemotypes of Fusarium graminearum Clade

PubMed Central

Wang, Jian-Hua; Li, He-Ping; Qu, Bo; Zhang, Jing-Bo; Huang, Tao; Chen, Fang-Fang; Liao, Yu-Cai

2008-01-01

Fusarium graminearum clade pathogens cause Fusarium head blight (FHB) or scab of wheat and other small cereal grains, producing different kinds of trichothecene mycotoxins that are detrimental to human and domestic animals. Type B trichothecene mycotoxins such as deoxynivalenol, 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON) and nivalenol (NIV) are the principal Fusarium mycotoxins reported in China, as well as in other countries. A genomic polymerase chain reaction (PCR) to predict chemotypes was developed based on the structural gene sequences of Tri13 genes involved in trichothecene mycotoxin biosynthesis pathways. A single pair of primers derived from the Tri13 genes detected a 583 bp fragment from 15-AcDON-chemotypes, a 644 bp fragment from 3-AcDON-chemotypes and an 859 bp fragment from NIV-producing strains. Fusarium strains from China, Nepal, USA and Europe were identified by this method, revealing their mycotoxin chemotypes identical to that obtained by chemical analyses of HPLC or GC/MS and other PCR assays. The mycotoxin chemotype-specific fragments were amplified from a highly variable region located in Tri13 genes with three deletions for 15-AcDON-chemotypes, two deletions for 3-AcDON-chemotypes and no deletion for NIV-producers. This PCR assay generated a single amplicon and thus should be more reliable than other PCR-based assays that showed the absence or presence of a PCR fragment since these assays may generate false-negative results. The results with strains from several different countries as well as from different hosts further indicated that this method should be globally applicable. This is a rapid, reliable and cost-effective method for the identification of type B trichothecene mycotoxin chemotypes in Fusarium species and food safety controls. PMID:19330088

Potent Plasmodium falciparum gametocytocidal activity of diaminonaphthoquinones, lead antimalarial chemotypes identified in an antimalarial compound screen.

PubMed

Tanaka, Takeshi Q; Guiguemde, W Armand; Barnett, David S; Maron, Maxim I; Min, Jaeki; Connelly, Michele C; Suryadevara, Praveen Kumar; Guy, R Kiplin; Williamson, Kim C

2015-03-01

Forty percent of the world's population is threatened by malaria, which is caused by Plasmodium parasites and results in an estimated 200 million clinical cases and 650,000 deaths each year. Drug resistance has been reported for all commonly used antimalarials and has prompted screens to identify new drug candidates. However, many of these new candidates have not been evaluated against the parasite stage responsible for transmission, gametocytes. If Plasmodium falciparum gametocytes are not eliminated, patients continue to spread malaria for weeks after asexual parasite clearance. Asymptomatic individuals can also harbor gametocyte burdens sufficient for transmission, and a safe, effective gametocytocidal agent could also be used in community-wide malaria control programs. Here, we identify 15 small molecules with nanomolar activity against late-stage gametocytes. Fourteen are diaminonaphthoquinones (DANQs), and one is a 2-imino-benzo[d]imidazole (IBI). One of the DANQs identified, SJ000030570, is a lead antimalarial candidate. In contrast, 94% of the 650 compounds tested are inactive against late-stage gametocytes. Consistent with the ineffectiveness of most approved antimalarials against gametocytes, of the 19 novel compounds with activity against known anti-asexual-stage targets, only 3 had any strong effect on gametocyte viability. These data demonstrate the distinct biology of the transmission stages and emphasize the importance of screening for gametocytocidal activity. The potent gametocytocidal activity of DANQ and IBI coupled with their efficacy against asexual parasites provides leads for the development of antimalarials with the potential to prevent both the symptoms and the spread of malaria. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Discovery of a series of dihydroquinoxalin-2(1H)-ones as selective BET inhibitors from a dual PLK1-BRD4 inhibitor.

PubMed

Hu, Jianping; Wang, Yingqing; Li, Yanlian; Xu, Lin; Cao, Danyan; Song, ShanShan; Damaneh, Mohammadali Soleimani; Wang, Xin; Meng, Tao; Chen, Yue-Lei; Shen, Jingkang; Miao, Zehong; Xiong, Bing

2017-09-08

Recent years have seen much effort to discover new chemotypes of BRD4 inhibitors. Interestingly, some kinase inhibitors have been demonstrated to be potent bromodomain inhibitors, especially the PLK1 inhibitor BI-2536 and the JAK2 inhibitor TG101209, which can bind to BRD4 with IC 50 values of 0.025 μM and 0.13 μM, respectively. Although the concept of dual inhibition is intriguing, selective BRD4 inhibitors are preferred as they may diminish off-target effects and provide more flexibility in anticancer drug combination therapy. Inspired by BI-2536, we designed and prepared a series of dihydroquinoxalin-2(1H)-one derivatives as selective bromodomain inhibitors. We found compound 54 had slightly higher activity than (+)-JQ1 in the fluorescence anisotropy assay and potent antiproliferative cellular activity in the MM.1S cell line. We have successfully solved the cocrystal structure of 52 in complex with BRD4-BD1, providing a solid structural basis for the binding mode of compounds of this series. Compound 54 exhibited high selectivity over most non-BET subfamily members and did not show bioactivity towards the PLK1 kinase at 10 or 1 μM. From in vivo studies, compound 54 demonstrated a good PK profile, and the results from in vivo pharmacological studies clearly showed the efficacy of 54 in the mouse MM.1S xenograft model. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Inforna 2.0: A Platform for the Sequence-Based Design of Small Molecules Targeting Structured RNAs.

PubMed

Disney, Matthew D; Winkelsas, Audrey M; Velagapudi, Sai Pradeep; Southern, Mark; Fallahi, Mohammad; Childs-Disney, Jessica L

2016-06-17

The development of small molecules that target RNA is challenging yet, if successful, could advance the development of chemical probes to study RNA function or precision therapeutics to treat RNA-mediated disease. Previously, we described Inforna, an approach that can mine motifs (secondary structures) within target RNAs, which is deduced from the RNA sequence, and compare them to a database of known RNA motif-small molecule binding partners. Output generated by Inforna includes the motif found in both the database and the desired RNA target, lead small molecules for that target, and other related meta-data. Lead small molecules can then be tested for binding and affecting cellular (dys)function. Herein, we describe Inforna 2.0, which incorporates all known RNA motif-small molecule binding partners reported in the scientific literature, a chemical similarity searching feature, and an improved user interface and is freely available via an online web server. By incorporation of interactions identified by other laboratories, the database has been doubled, containing 1936 RNA motif-small molecule interactions, including 244 unique small molecules and 1331 motifs. Interestingly, chemotype analysis of the compounds that bind RNA in the database reveals features in small molecule chemotypes that are privileged for binding. Further, this updated database expanded the number of cellular RNAs to which lead compounds can be identified.

Greenhouse studies reveal increased aggressiveness of emergent Canadian Fusarium graminearum chemotypes in wheat

USDA-ARS?s Scientific Manuscript database

The role of Fusarium graminearum trichothecene-chemotypes in disease outcomes was evaluated in a series of wheat lines with different levels of resistance to Fusarium Head Blight (FHB). Four inocula, each consisting of a composite of four strains with either 15-acetyldeoxynivalenol (ADON) chemotypes...

Chemotypes of essential oil of unripe galls of Pistacia atlantica Desf. from Algeria.

PubMed

Sifi, Ibrahim; Gourine, Nadhir; Gaydou, Emile M; Yousfi, Mohamed

2015-01-01

The essential oils (EOs) of unripe galls (from male and female plants) of a total number of 52 samples of Pistacia atlantica collected from different regions in Algeria were analysed by GC/MS and GC. The yields of the extraction of the EO by hydrodistillation vary from low to high values (0.08-1.89% v/w). The results of both methods of principal component analysis and hierarchical ascendant classification revealed the presence of two different chemotypes: α-pinene chemotype and α-pinene/sabinene/terpinen-4-ol chemotype.

Structure-Activity Relationships of Small Molecule Autotaxin Inhibitors with a Discrete Binding Mode.

PubMed

Miller, Lisa M; Keune, Willem-Jan; Castagna, Diana; Young, Louise C; Duffy, Emma L; Potjewyd, Frances; Salgado-Polo, Fernando; Engel García, Paloma; Semaan, Dima; Pritchard, John M; Perrakis, Anastassis; Macdonald, Simon J F; Jamieson, Craig; Watson, Allan J B

2017-01-26

Autotaxin (ATX) is a secreted enzyme responsible for the hydrolysis of lysophosphatidylcholine (LPC) to the bioactive lysophosphatidic acid (LPA) and choline. The ATX-LPA signaling pathway is implicated in cell survival, migration, and proliferation; thus, the inhibition of ATX is a recognized therapeutic target for a number of diseases including fibrotic diseases, cancer, and inflammation, among others. Many of the developed synthetic inhibitors for ATX have resembled the lipid chemotype of the native ligand; however, a small number of inhibitors have been described that deviate from this common scaffold. Herein, we report the structure-activity relationships (SAR) of a previously reported small molecule ATX inhibitor. We show through enzyme kinetics studies that analogues of this chemotype are noncompetitive inhibitors, and by using a crystal structure with ATX we confirm the discrete binding mode.

The Role of Trichothecene-Chemotypes in Fusarium Head Blight Disease Spread and Trichothecene Accumulation in Wheat

USDA-ARS?s Scientific Manuscript database

Three major strain-specific trichothecene-chemotypes have been identified in F. graminearum-infected crops in North America: 3-acetyldeoxynivalenol (3ADON), 15ADON, and nivalenol (NIV). The emergence of the 3ADON- and NIV-chemotypes on the continent is a fairly recent phenomenon. In addition, str...

A Small Molecule that Targets r(CGG)exp and Improves Defects in Fragile X-Associated Tremor Ataxia Syndrome

PubMed Central

Disney, Matthew D.; Liu, Biao; Yang, Wang-Yong; Sellier, Chantal; Tran, Tuan; Charlet-Berguerand, Nicolas; Childs-Disney, Jessica L.

2012-01-01

The development of small molecule chemical probes or therapeutics that target RNA remains a significant challenge despite the great interest in such compounds. The most significant barrier to compound development is a lack of knowledge of the chemical and RNA motif spaces that interact specifically. Herein, we describe a bioactive small molecule probe that targets expanded r(CGG) repeats, or r(CGG)exp , that causes Fragile X-associated Tremor Ataxia Syndrome (FXTAS). The compound was identified by using information on the chemotypes and RNA motifs that interact. Specifically, 9-hydroxy-5,11-dimethyl-2-(2-(piperidin-1-yl)ethyl)-6H-pyrido[4,3-b]carbazol-2-ium, binds the 5’CGG/3’GGC motifs in r(CGG)exp and disrupts a toxic r(CGG)exp -protein complex in vitro. Structure-activity relationships (SAR) studies determined that the alkylated pyridyl and phenolic side chains are important chemotypes that drive molecular recognition to r(CGG)exp . Importantly, the compound is efficacious in FXTAS model cellular systems as evidenced by its ability to improve FXTAS-associated pre-mRNA splicing defects and to reduce the size and number of r(CGG)exp -protein aggregates. This approach may establish a general strategy to identify lead ligands that target RNA while also providing a chemical probe to dissect the varied mechanisms by which r(CGG)exp promotes toxicity. PMID:22948243

A small molecule that targets r(CGG)(exp) and improves defects in fragile X-associated tremor ataxia syndrome.

PubMed

Disney, Matthew D; Liu, Biao; Yang, Wang-Yong; Sellier, Chantal; Tran, Tuan; Charlet-Berguerand, Nicolas; Childs-Disney, Jessica L

2012-10-19

The development of small molecule chemical probes or therapeutics that target RNA remains a significant challenge despite the great interest in such compounds. The most significant barrier to compound development is defining which chemical and RNA motif spaces interact specifically. Herein, we describe a bioactive small molecule probe that targets expanded r(CGG) repeats, or r(CGG)(exp), that causes Fragile X-associated Tremor Ataxia Syndrome (FXTAS). The compound was identified by using information on the chemotypes and RNA motifs that interact. Specifically, 9-hydroxy-5,11-dimethyl-2-(2-(piperidin-1-yl)ethyl)-6H-pyrido[4,3-b]carbazol-2-ium binds the 5'CGG/3'GGC motifs in r(CGG)(exp) and disrupts a toxic r(CGG)(exp)-protein complex in vitro. Structure-activity relationship studies determined that the alkylated pyridyl and phenolic side chains are important chemotypes that drive molecular recognition of r(CGG)(exp). Importantly, the compound is efficacious in FXTAS model cellular systems as evidenced by its ability to improve FXTAS-associated pre-mRNA splicing defects and to reduce the size and number of r(CGG)(exp)-containing nuclear foci. This approach may establish a general strategy to identify lead ligands that target RNA while also providing a chemical probe to dissect the varied mechanisms by which r(CGG)(exp) promotes toxicity.

Lippia origanoides chemotype differentiation based on essential oil GC-MS and principal component analysis.

PubMed

Stashenko, Elena E; Martínez, Jairo R; Ruíz, Carlos A; Arias, Ginna; Durán, Camilo; Salgar, William; Cala, Mónica

2010-01-01

Chromatographic (GC/flame ionization detection, GC/MS) and statistical analyses were applied to the study of essential oils and extracts obtained from flowers, leaves, and stems of Lippia origanoides plants, growing wild in different Colombian regions. Retention indices, mass spectra, and standard substances were used in the identification of 139 substances detected in these essential oils and extracts. Principal component analysis allowed L. origanoides classification into three chemotypes, characterized according to their essential oil major components. Alpha- and beta-phellandrenes, p-cymene, and limonene distinguished chemotype A; carvacrol and thymol were the distinctive major components of chemotypes B and C, respectively. Pinocembrin (5,7-dihydroxyflavanone) was found in L. origanoides chemotype A supercritical fluid (CO(2)) extract at a concentration of 0.83+/-0.03 mg/g of dry plant material, which makes this plant an interesting source of an important bioactive flavanone with diverse potential applications in cosmetic, food, and pharmaceutical products.

Discovery of novel inhibitors of the NorA multidrug transporter of Staphylococcus aureus.

PubMed

Brincat, Jean Pierre; Carosati, Emanuele; Sabatini, Stefano; Manfroni, Giuseppe; Fravolini, Arnaldo; Raygada, Jose L; Patel, Diixa; Kaatz, Glenn W; Cruciani, Gabriele

2011-01-13

Four novel inhibitors of the NorA efflux pump of Staphylococcus aureus, discovered through a virtual screening process, are reported. The four compounds belong to different chemical classes and were tested for their in vitro ability to block the efflux of a well-known NorA substrate, as well as for their ability to potentiate the effect of ciprofloxacin (CPX) on several strains of S. aureus, including a NorA overexpressing strain. Additionally, the MIC values of each of the compounds individually are reported. A structure-activity relationship study was also performed on these novel chemotypes, revealing three new compounds that are also potent NorA inhibitors. The virtual screening procedure employed FLAP, a new methodology based on GRID force field descriptors.

Bis-Benzimidazole Hits against Naegleria fowleri Discovered with New High-Throughput Screens

PubMed Central

Rice, Christopher A.; Colon, Beatrice L.; Alp, Mehmet; Göker, Hakan; Boykin, David W.

2015-01-01

Naegleria fowleri is a pathogenic free-living amoeba (FLA) that causes an acute fatal disease known as primary amoebic meningoencephalitis (PAM). The major problem for infections with any pathogenic FLA is a lack of effective therapeutics, since PAM has a case mortality rate approaching 99%. Clearly, new drugs that are potent and have rapid onset of action are needed to enhance the treatment regimens for PAM. Diamidines have demonstrated potency against multiple pathogens, including FLA, and are known to cross the blood-brain barrier to cure other protozoan diseases of the central nervous system. Therefore, amidino derivatives serve as an important chemotype for discovery of new drugs. In this study, we validated two new in vitro assays suitable for medium- or high-throughput drug discovery and used these for N. fowleri. We next screened over 150 amidino derivatives of multiple structural classes and identified two hit series with nM potency that are suitable for further lead optimization as new drugs for this neglected disease. These include both mono- and diamidino derivatives, with the most potent compound (DB173) having a 50% inhibitory concentration (IC50) of 177 nM. Similarly, we identified 10 additional analogues with IC50s of <1 μM, with many of these having reasonable selectivity indices. The most potent hits were >500 times more potent than pentamidine. In summary, the mono- and diamidino derivatives offer potential for lead optimization to develop new drugs to treat central nervous system infections with N. fowleri. PMID:25605363

Explorations of Substituted Urea Functionality for Discovery of New Activators of the Heme Regulated Inhibitor Kinase

PubMed Central

Chen, Ting; Takrouri, Khuloud; Hee-Hwang, Sung; Rana, Sandeep; Yefidoff-Freedman, Revital; Halperin, Jose; Natarajan, Amarnath; Morisseau, Christophe; Hammock, Bruce; Chorev, Michael; Aktas, Bertal H.

2014-01-01

Heme-regulated inhibitor kinase (HRI), an eukaryotic translation initiation factor 2 alpha (eIF2α) kinase, plays critical roles in cell proliferation, differentiation, and adaptation to cytoplasmic stress. HRI is also a critical modifier of hemoglobin disorders such as β-thalassemia. We previously identified N,N′-diarylureas as potent activators of HRI suitable for studying biology of this important kinase. To expand the repertoire of chemotypes that activate HRI we screened a ~1,900 member N,N′-disubstituted urea library in the surrogate eIF2α phosphorylation assay identifying N-aryl,N′-cyclohexylphenoxyurea as a promising scaffold. We validated hit compounds as a bona-fide HRI activators in secondary assays and explored contributions of substitutions on the N-aryl and N′-cyclohexylphenoxy groups to their activity by studying focused libraries of complementing analogs. We tested these N-aryl,N′-cyclohexylphenoxyureas in the surrogate eIF2α phosphorylation and cell proliferation assays, demonstrating significantly improved bioactivities and specificities. We consider these compounds to represent lead candidates for the development of potent and specific HRI activators. PMID:24261904

The effect of various zinc binding groups on inhibition of histone deacetylases 1-11.

PubMed

Madsen, Andreas S; Kristensen, Helle M E; Lanz, Gyrithe; Olsen, Christian A

2014-03-01

Histone deacetylases (HDACs) have the ability to cleave the acetyl groups of ε-N-acetylated lysine residues in a variety of proteins. Given that human cells contain thousands of different acetylated lysine residues, HDACS may regulate a wide variety of processes including some implicated in conditions such as cancer and neurodegenerative disorders. Herein we report the synthesis and in vitro biochemical profiling of a series of compounds, including known inhibitors as well as novel chemotypes, that incorporate putative new zinc binding domains. By evaluating the compound collection against all 11 recombinant human HDACs, we found that the trifluoromethyl ketone functionality provides potent inhibition of all four subclasses of the Zn(2+) -dependent HDACs. Potent inhibition was observed with two different scaffolds, demonstrating the efficiency of the trifluoromethyl ketone moiety as a zinc binding motif. Interestingly, we also identified silanediol as a zinc binding group with potential for future development of non-hydroxamate class I and class IIb HDAC inhibitors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Epothilones as lead structures for the synthesis-based discovery of new chemotypes for microtubule stabilization.

PubMed

Feyen, Fabian; Cachoux, Frédéric; Gertsch, Jürg; Wartmann, Markus; Altmann, Karl-Heinz

2008-01-01

Epothilones are macrocyclic bacterial natural products with potent microtubule-stabilizing and antiproliferative activity. They have served as successful lead structures for the development of several clinical candidates for anticancer therapy. However, the structural diversity of this group of clinical compounds is rather limited, as their structures show little divergence from the original natural product leads. Our own research has explored the question of whether epothilones can serve as a basis for the development of new structural scaffolds, or chemotypes, for microtubule stabilization that might serve as a basis for the discovery of new generations of anticancer drugs. We have elaborated a series of epothilone-derived macrolactones whose overall structural features significantly deviate from those of the natural epothilone scaffold and thus define new structural families of microtubule-stabilizing agents. Key elements of our hypermodification strategy are the change of the natural epoxide geometry from cis to trans, the incorporation of a conformationally constrained side chain, the removal of the C3-hydroxyl group, and the replacement of C12 with nitrogen. So far, this approach has yielded analogs 30 and 40 that are the most advanced, the most rigorously modified, structures, both of which are potent antiproliferative agents with low nanomolar activity against several human cancer cell lines in vitro. The synthesis was achieved through a macrolactone-based strategy or a high-yielding RCM reaction. The 12-aza-epothilone ("azathilone" 40) may be considered a "non-natural" natural product that still retains most of the overall structural characteristics of a true natural product but is structurally unique, because it lies outside of the general scope of Nature's biosynthetic machinery for polyketide synthesis. Like natural epothilones, both 30 and 40 promote tubulin polymerization in vitro and at the cellular level induce cell cycle arrest in mitosis. These facts indicate that cancer cell growth inhibition by these compounds is based on the same mechanistic underpinnings as those for natural epothilones. Interestingly, the 9,10-dehydro analog of 40 is significantly less active than the saturated parent compound, which is contrary to observations for natural epothilones B or D. This may point to differences in the bioactive conformations of N-acyl-12-aza-epothilones like 40 and natural epothilones. In light of their distinct structural features, combined with an epothilone-like (and taxol-like) in vitro biological profile, 30 and 40 can be considered as representative examples of new chemotypes for microtubule stabilization. As such, they may offer the same potential for pharmacological differentiation from the original epothilone leads as various newly discovered microtubule-stabilizing natural products with macrolactone structures, such as laulimalide, peloruside, or dictyostatin.

Novel colchicine-site binders with a cyclohexanedione scaffold identified through a ligand-based virtual screening approach.

PubMed

Canela, María-Dolores; Pérez-Pérez, María-Jesús; Noppen, Sam; Sáez-Calvo, Gonzalo; Díaz, J Fernando; Camarasa, María-José; Liekens, Sandra; Priego, Eva-María

2014-05-22

Vascular disrupting agents (VDAs) constitute an innovative anticancer therapy that targets the tumor endothelium, leading to tumor necrosis. Our approach for the identification of new VDAs has relied on a ligand 3-D shape similarity virtual screening (VS) approach using the ROCS program as the VS tool and as query colchicine and TN-16, which both bind the α,β-tubulin dimer. One of the hits identified, using TN-16 as query, has been explored by the synthesis of its structural analogues, leading to 2-(1-((2-methoxyphenyl)amino)ethylidene)-5-phenylcyclohexane-1,3-dione (compound 16c) with an IC50 = 0.09 ± 0.01 μM in HMEC-1 and BAEC, being 100-fold more potent than the initial hit. Compound 16c caused cell cycle arrest in the G2/M phase and interacted with the colchicine-binding site in tubulin, as confirmed by a competition assay with N,N'-ethylenebis(iodoacetamide) and by fluorescence spectroscopy. Moreover, 16c destroyed an established endothelial tubular network at 1 μM and inhibited the migration and invasion of human breast carcinoma cells at 0.4 μM. In conclusion, our approach has led to a new chemotype of promising antiproliferative compounds with antimitotic and potential VDA properties.

Comparative transcriptome analysis of different chemotypes elucidates withanolide biosynthesis pathway from medicinal plant Withania somnifera

PubMed Central

Gupta, Parul; Goel, Ridhi; Agarwal, Aditya Vikram; Asif, Mehar Hasan; Sangwan, Neelam Singh; Sangwan, Rajender Singh; Trivedi, Prabodh Kumar

2015-01-01

Withania somnifera is one of the most valuable medicinal plants synthesizing secondary metabolites known as withanolides. Despite pharmaceutical importance, limited information is available about the biosynthesis of withanolides. Chemo-profiling of leaf and root tissues of Withania suggest differences in the content and/or nature of withanolides in different chemotypes. To identify genes involved in chemotype and/or tissue-specific withanolide biosynthesis, we established transcriptomes of leaf and root tissues of distinct chemotypes. Genes encoding enzymes for intermediate steps of terpenoid backbone biosynthesis with their alternatively spliced forms and paralogous have been identified. Analysis suggests differential expression of large number genes among leaf and root tissues of different chemotypes. Study also identified differentially expressing transcripts encoding cytochrome P450s, glycosyltransferases, methyltransferases and transcription factors which might be involved in chemodiversity in Withania. Virus induced gene silencing of the sterol ∆7-reductase (WsDWF5) involved in the synthesis of 24-methylene cholesterol, withanolide backbone, suggests role of this enzyme in biosynthesis of withanolides. Information generated, in this study, provides a rich resource for functional analysis of withanolide-specific genes to elucidate chemotype- as well as tissue-specific withanolide biosynthesis. This genomic resource will also help in development of new tools for functional genomics and breeding in Withania. PMID:26688389

The inheritance of chemical phenotype in Cannabis sativa L.

PubMed Central

de Meijer, Etienne P M; Bagatta, Manuela; Carboni, Andrea; Crucitti, Paola; Moliterni, V M Cristiana; Ranalli, Paolo; Mandolino, Giuseppe

2003-01-01

Four crosses were made between inbred Cannabis sativa plants with pure cannabidiol (CBD) and pure Delta-9-tetrahydrocannabinol (THC) chemotypes. All the plants belonging to the F(1)'s were analyzed by gas chromatography for cannabinoid composition and constantly found to have a mixed CBD-THC chemotype. Ten individual F(1) plants were self-fertilized, and 10 inbred F(2) offspring were collected and analyzed. In all cases, a segregation of the three chemotypes (pure CBD, mixed CBD-THC, and pure THC) fitting a 1:2:1 proportion was observed. The CBD/THC ratio was found to be significantly progeny specific and transmitted from each F(1) to the F(2)'s derived from it. A model involving one locus, B, with two alleles, B(D) and B(T), is proposed, with the two alleles being codominant. The mixed chemotypes are interpreted as due to the genotype B(D)/B(T) at the B locus, while the pure-chemotype plants are due to homozygosity at the B locus (either B(D)/B(D) or B(T)/B(T)). It is suggested that such codominance is due to the codification by the two alleles for different isoforms of the same synthase, having different specificity for the conversion of the common precursor cannabigerol into CBD or THC, respectively. The F(2) segregating groups were used in a bulk segregant analysis of the pooled DNAs for screening RAPD primers; three chemotype-associated markers are described, one of which has been transformed in a sequence-characterized amplified region (SCAR) marker and shows tight linkage to the chemotype and codominance. PMID:12586720

The study of flavonolignan association patterns in fruits of diverging Silybum marianum (L.) Gaertn. chemotypes provides new insights into the silymarin biosynthetic pathway.

PubMed

Martinelli, Tommaso; Whittaker, Anne; Benedettelli, Stefano; Carboni, Andrea; Andrzejewska, Jadwiga

2017-12-01

Silymarin is the phytochemical with medicinal properties extracted from Silybum marianum (L.) Gaertn. fruits. Yet, little information is available about silymarin biosynthesis. Moreover, the generally accepted pathway, formulated thus far, is not in agreement with actual experimental measurements on flavonolignan contents. The present work analyses flavonolignan and taxifolin content in 201 S. marianum samples taking into consideration a wide phenotypic variability. Two stable chemotypes were identified: one characterized by both high silychristin and silybin content (chemotype A) and another by a high silydianin content (chemotype B). Through the correlation analysis of samples divided according to chemotype, it was possible to construct a simplified silymarin biosynthetic pathway that is sufficiently versatile in explaining experimental results responding to the actually unresolved questions about this process. The proposed pathway highlights that three separate and equally sized metabolite pools exist, namely: diastereoisomers A (silybin A plus isosilybin A), diastereoisomers B (silybin B plus isosilybin B) and silychristin. In both A and B diastereoisomers pools, isosilybin A and isosilybin B always represent a given amount of the metabolite flux through the specific metabolite pool suggesting the possible involvement of dirigent protein-like enzymes. We suggest that chemotype B possesses a complete silymarin biosynthetic pathway in which silydianin biosynthesis is enzymatically controlled. On the contrary, chemotype A is probably a natural mutant unable to biosynthesize silydianin. The present simplified pathway for silymarin biosynthesis will constitute an important tool for the further understanding of the reactions that drive flavonolignan biosynthesis in S. marianum. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bergamot versus beetle: evidence for intraspecific chemical specialization

PubMed Central

Keefover-Ring, Ken

2015-01-01

A large proportion of phytophagous insects show host plant specificity (monophagy or oligophagy), often determined by host secondary chemistry. Yet, even specialists can be negatively affected by host chemistry at high levels or with novel compounds, which may manifest itself if their host species is chemically variable. This study tested for reciprocal effects of a specialist tortoise beetle (Physonota unipunctata) feeding on a host plant (Monarda fistulosa) with two monoterpene chemotypes [thymol (T) and carvacrol (C)] using a controlled field experiment where larvae fed on caged plants of both chemotypes, haphazardly collected natural plants with and without beetle damage, and growth chamber experiments where larvae that hatched and briefly fed on one chemotype were reared on either chemotype. In the field experiment, plant chemotype did not affect larval weight or length, but did influence larval survival with almost 8.3 % more surviving on T plants. Herbivores reduced seed head area (86.5 % decrease), stem mass (41.2 %) and stem height (21.1 %) of caged plants, but this was independent of host chemotype. Natural plants experienced similar reductions in these variables (74.0, 41.4 and 8.7 %) and T chemotypes were more frequently damaged. In the growth chamber, larval relative growth rate (RGR) differed for both feeding history and year. Larvae from T natal plants reared on T hosts grew at almost twice the rate of those from C and reared on T. Larvae from either T or C natal plants reared on C plants showed intermediate growth rates. Additional analyses revealed natal plant chemotype as the most important factor, with the RGR of larvae from T natal plants almost one-third higher than that of those from C natal plants. These cumulative results demonstrate intraspecific variation in plant resistance that may lead to herbivore specialization on distinct host chemistry, which has implications for the evolutionary trajectory of both the insect and plant species. PMID:26578745

Bergamot versus beetle: evidence for intraspecific chemical specialization.

PubMed

Keefover-Ring, Ken

2015-11-16

A large proportion of phytophagous insects show host plant specificity (monophagy or oligophagy), often determined by host secondary chemistry. Yet, even specialists can be negatively affected by host chemistry at high levels or with novel compounds, which may manifest itself if their host species is chemically variable. This study tested for reciprocal effects of a specialist tortoise beetle (Physonota unipunctata) feeding on a host plant (Monarda fistulosa) with two monoterpene chemotypes [thymol (T) and carvacrol (C)] using a controlled field experiment where larvae fed on caged plants of both chemotypes, haphazardly collected natural plants with and without beetle damage, and growth chamber experiments where larvae that hatched and briefly fed on one chemotype were reared on either chemotype. In the field experiment, plant chemotype did not affect larval weight or length, but did influence larval survival with almost 8.3 % more surviving on T plants. Herbivores reduced seed head area (86.5 % decrease), stem mass (41.2 %) and stem height (21.1 %) of caged plants, but this was independent of host chemotype. Natural plants experienced similar reductions in these variables (74.0, 41.4 and 8.7 %) and T chemotypes were more frequently damaged. In the growth chamber, larval relative growth rate (RGR) differed for both feeding history and year. Larvae from T natal plants reared on T hosts grew at almost twice the rate of those from C and reared on T. Larvae from either T or C natal plants reared on C plants showed intermediate growth rates. Additional analyses revealed natal plant chemotype as the most important factor, with the RGR of larvae from T natal plants almost one-third higher than that of those from C natal plants. These cumulative results demonstrate intraspecific variation in plant resistance that may lead to herbivore specialization on distinct host chemistry, which has implications for the evolutionary trajectory of both the insect and plant species. Published by Oxford University Press on behalf of the Annals of Botany Company.

Virtual screening filters for the design of type II p38 MAP kinase inhibitors: a fragment based library generation approach.

PubMed

Badrinarayan, Preethi; Sastry, G Narahari

2012-04-01

In this work, we introduce the development and application of a three-step scoring and filtering procedure for the design of type II p38 MAP kinase leads using allosteric fragments extracted from virtual screening hits. The design of the virtual screening filters is based on a thorough evaluation of docking methods, DFG-loop conformation, binding interactions and chemotype specificity of the 138 p38 MAP kinase inhibitors from Protein Data Bank bound to DFG-in and DFG-out conformations using Glide, GOLD and CDOCKER. A 40 ns molecular dynamics simulation with the apo, type I with DFG-in and type II with DFG-out forms was carried out to delineate the effects of structural variations on inhibitor binding. The designed docking-score and sub-structure filters were first tested on a dataset of 249 potent p38 MAP kinase inhibitors from seven diverse series and 18,842 kinase inhibitors from PDB, to gauge their capacity to discriminate between kinase and non-kinase inhibitors and likewise to selectively filter-in target-specific inhibitors. The designed filters were then applied in the virtual screening of a database of ten million (10⁷) compounds resulting in the identification of 100 hits. Based on their binding modes, 98 allosteric fragments were extracted from the hits and a fragment library was generated. New type II p38 MAP kinase leads were designed by tailoring the existing type I ATP site binders with allosteric fragments using a common urea linker. Target specific virtual screening filters can thus be easily developed for other kinases based on this strategy to retrieve target selective compounds. Copyright © 2012 Elsevier Inc. All rights reserved.

Fighting obesity with a sugar-based library: discovery of novel MCH-1R antagonists by a new computational-VAST approach for exploration of GPCR binding sites.

PubMed

Heifetz, Alexander; Barker, Oliver; Verquin, Geraldine; Wimmer, Norbert; Meutermans, Wim; Pal, Sandeep; Law, Richard J; Whittaker, Mark

2013-05-24

Obesity is an increasingly common disease. While antagonism of the melanin-concentrating hormone-1 receptor (MCH-1R) has been widely reported as a promising therapeutic avenue for obesity treatment, no MCH-1R antagonists have reached the market. Discovery and optimization of new chemical matter targeting MCH-1R is hindered by reduced HTS success rates and a lack of structural information about the MCH-1R binding site. X-ray crystallography and NMR, the major experimental sources of structural information, are very slow processes for membrane proteins and are not currently feasible for every GPCR or GPCR-ligand complex. This situation significantly limits the ability of these methods to impact the drug discovery process for GPCR targets in "real-time", and hence, there is an urgent need for other practical and cost-efficient alternatives. We present here a conceptually pioneering approach that integrates GPCR modeling with design, synthesis, and screening of a diverse library of sugar-based compounds from the VAST technology (versatile assembly on stable templates) to provide structural insights on the MCH-1R binding site. This approach creates a cost-efficient new avenue for structure-based drug discovery (SBDD) against GPCR targets. In our work, a primary VAST hit was used to construct a high-quality MCH-1R model. Following model validation, a structure-based virtual screen yielded a 14% hit rate and 10 novel chemotypes of potent MCH-1R antagonists, including EOAI3367472 (IC50 = 131 nM) and EOAI3367474 (IC50 = 213 nM).

Repellent activity of catmint, Nepeta cataria, and iridoid nepetalactone isomers against Afro-tropical mosquitoes, ixodid ticks and red poultry mites.

PubMed

Birkett, Michael A; Hassanali, Ahmed; Hoglund, Solveig; Pettersson, Jan; Pickett, John A

2011-01-01

The repellent activity of the essential oil of the catmint plant, Nepeta cataria (Lamiaceae), and the main iridoid compounds (4aS,7S,7aR) and (4aS,7S,7aS)-nepetalactone, was assessed against (i) major Afro-tropical pathogen vector mosquitoes, i.e. the malaria mosquito, Anopheles gambiae s.s. and the Southern house mosquito, Culex quinquefasciatus, using a World Health Organisation (WHO)-approved topical application bioassay (ii) the brown ear tick, Rhipicephalus appendiculatus, using a climbing repellency assay, and (iii) the red poultry mite, Dermanyssus gallinae, using field trapping experiments. Gas chromatography (GC) and coupled GC-mass spectrometry (GC-MS) analysis of two N. cataria chemotypes (A and B) used in the repellency assays showed that (4aS,7S,7aR) and (4aS,7S,7aS)-nepetalactone were present in different proportions, with one of the oils (from chemotype A) being dominated by the (4aS,7S,7aR) isomer (91.95% by GC), and the other oil (from chemotype B) containing the two (4aS,7S,7aR) and (4aS,7S,7aS) isomers in 16.98% and 69.83% (by GC), respectively. The sesquiterpene hydrocarbon (E)-(1R,9S)-caryophyllene was identified as the only other major component in the oils (8.05% and 13.19% by GC, respectively). Using the topical application bioassay, the oils showed high repellent activity (chemotype A RD(50)=0.081 mg cm(-2) and chemotype B RD(50)=0.091 mg cm(-2)) for An. gambiae comparable with the synthetic repellent DEET (RD(50)=0.12 mg cm(-2)), whilst for Cx. quinquefasciatus, lower repellent activity was recorded (chemotype A RD(50)=0.34 mg cm(-2) and chemotype B RD(50)=0.074 mg cm(-2)). Further repellency testing against An. gambiae using the purified (4aS,7S,7aR) and (4aS,7S,7aS)-nepetalactone isomers revealed overall lower repellent activity, compared to the chemotype A and B oils. Testing of binary mixtures of the (4aS,7S,7aR) and (4aS,7S,7aS) isomers across a range of ratios, but all at the same overall dose (0.1 mg), revealed not only a synergistic effect between the two, but also a surprising ratio-dependent effect, with lower activity for the pure isomers and equivalent or near-equivalent mixtures, but higher activity for non-equivalent ratios. Furthermore, a binary mixture of (4aS,7S,7aR) and (4aS,7S,7aS) isomers, in a ratio equivalent to that found in chemotype B oil, was less repellent than the oil itself, when tested at two doses equivalent to 0.1 and 0.01 mg chemotype B oil. The three-component blend including (E)-(1R,9S)-caryophyllene at the level found in chemotype B oil had the same activity as chemotype B oil. In a tick climbing repellency assay using R. appendiculatus, the oils showed high repellent activity comparable with data for other repellent essential oils (chemotype A RD(50)=0.005 mg and chemotype B RD(50)=0.0012 mg). In field trapping assays with D. gallinae, addition of the chemotype A and B oils, and a combination of the two, to traps pre-conditioned with D. gallinae, all resulted in a significant reduction of D. gallinae trap capture. In summary, these data suggest that although the nepetalactone isomers have the potential to be used in human and livestock protection against major pathogen vectors, intact, i.e. unfractionated, Nepeta spp. oils offer potentially greater protection, due to the presence of both nepetalactone isomers and other components such as (E)-(1R,9S)-caryophyllene. Copyright © 2010 Elsevier Ltd. All rights reserved.

Trypanosoma Cruzi Cyp51 Inhibitor Derived from a Mycobacterium Tuberculosis Screen Hit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Chiung-Kuang; Doyle, Patricia S.; Yermalitskaya, Liudmila V.

2009-02-18

The two front-line drugs for chronic Trypanosoma cruzi infections are limited by adverse side-effects and declining efficacy. One potential new target for Chagas disease chemotherapy is sterol 14{alpha}-demethylase (CYP51), a cytochrome P450 enzyme involved in biosynthesis of membrane sterols. In a screening effort targeting Mycobacterium tuberculosis CYP51 (CYP51{sub Mt}), we previously identified the N-[4-pyridyl]-formamide moiety as a building block capable of delivering a variety of chemotypes into the CYP51 active site. In that work, the binding modes of several second generation compounds carrying this scaffold were determined by high-resolution co-crystal structures with CYP51{sub Mt}. Subsequent assays against the CYP51 orthologuemore » in T. cruzi, CYP51{sub Tc}, demonstrated that two of the compounds tested in the earlier effort bound tightly to this enzyme. Both were tested in vitro for inhibitory effects against T. cruzi and the related protozoan parasite Trypanosoma brucei, the causative agent of African sleeping sickness. One of the compounds had potent, selective anti-T. cruzi activity in infected mouse macrophages. Cure of treated host cells was confirmed by prolonged incubation in the absence of the inhibiting compound. Discrimination between T. cruzi and T. brucei CYP51 by the inhibitor was largely based on the variability (phenylalanine versus isoleucine) of a single residue at a critical position in the active site. CYP51{sub Mt}-based crystal structure analysis revealed that the functional groups of the two tightly bound compounds are likely to occupy different spaces in the CYP51 active site, suggesting the possibility of combining the beneficial features of both inhibitors in a third generation of compounds to achieve more potent and selective inhibition of CYP51{sub Tc}. Enzyme sterol 14{alpha}-demethylase (CYP51) is a well-established target for anti-fungal therapy and is a prospective target for Chagas disease therapy. We previously identified a chemical scaffold capable of delivering a variety of chemical structures into the CYP51 active site. In this work the binding modes of several second generation compounds carrying this scaffold were determined in high-resolution co-crystal structures with CYP51 of Mycobacterium tuberculosis. Subsequent assays against CYP51 in Trypanosoma cruzi, the agent of Chagas disease, demonstrated that two of the compounds bound tightly to the enzyme. Both were tested for inhibitory effects against T. cruzi and the related protozoan parasite Trypanosoma brucei. One of the compounds had potent, selective anti-T. cruzi activity in infected mouse macrophages. This compound is currently being evaluated in animal models of Chagas disease. Discrimination between T. cruzi and T. brucei CYP51 by the inhibitor was largely based on the variability of a single amino acid residue at a critical position in the active site. Our work is aimed at rational design of potent and highly selective CYP51 inhibitors with potential to become therapeutic drugs. Drug selectivity to prevent host-pathogen cross-reactivity is pharmacologically important, because CYP51 is present in human host.« less

Biosynthesis of estragole and methyl-eugenol in sweet basil (Ocimum basilicum L). Developmental and chemotypic association of allylphenol O-methyltransferase activities.

PubMed

Lewinsohn, E; Ziv-Raz, I; Dudai, N; Tadmor, Y; Lastochkin, E; Larkov, O; Chaimovitsh, D; Ravid, U; Putievsky, E; Pichersky, E; Shoham, Y

2000-12-07

Sweet basil (Ocimum basilicum L., Lamiaceae) is a common herb, used for culinary and medicinal purposes. The essential oils of different sweet basil chemotypes contain various proportions of the allyl phenol derivatives estragole (methyl chavicol), eugenol, and methyl eugenol, as well as the monoterpene alcohol linalool. To monitor the developmental regulation of estragole biosynthesis in sweet basil, an enzymatic assay for S-adenosyl-L-methionine (SAM):chavicol O-methyltransferase activity was developed. Young leaves display high levels of chavicol O-methyltransferase activity, but the activity was negligible in older leaves, indicating that the O-methylation of chavicol primarily occurs early during leaf development. The O-methyltransferase activities detected in different sweet basil genotypes differed in their substrate specificities towards the methyl acceptor substrate. In the high-estragole-containing chemotype R3, the O-methyltransferase activity was highly specific for chavicol, while eugenol was virtually not O-methylated. In contrast, chemotype 147/97, that contains equal levels of estragole and methyl eugenol, displayed O-methyltransferase activities that accepted both chavicol and eugenol as substrates, generating estragole and methyl eugenol, respectively. Chemotype SW that contains high levels of eugenol, but lacks both estragole and methyl eugenol, had apparently no allylphenol dependent O-methyltransferase activities. These results indicate the presence of at least two types of allylphenol-specific O-methyltransferase activities in sweet basil chemotypes, one highly specific for chavicol; and a different one that can accept eugenol as a substrate. The relative availability and substrate specificities of these O-methyltransferase activities biochemically rationalizes the variation in the composition of the essential oils of these chemotypes.

Chemotype diversity of indigenous Dalmatian sage (Salvia officinalis L.) populations in Montenegro.

PubMed

Stešević, Danijela; Ristić, Mihailo; Nikolić, Vuko; Nedović, Marijana; Caković, Danka; Šatović, Zlatko

2014-01-01

To identify how many chemotypes of Salvia officinalis exist in Montenegro, the chemical composition of the essential oils of 12 wild-growing populations was determined by GC-FID and GC/MS analyses. Among the 40 identified constituents, the most abundant were cis-thujone (16.98-40.35%), camphor (12.75-35.37%), 1,8-cineol (6.40-12.06%), trans-thujone (1.5-10.35%), camphene (2.26-9.97%), borneol (0.97-8.81%), viridiflorol (3.46-7.8%), limonene (1.8-6.47%), α-pinene (1.59-5.46%), and α-humulene (1.77-5.02%). The composition of the essential oils under study did not meet the ISO 9909 requirements, while the oils of populations P02-P04, P09, and P10 complied with the German Drug Codex. A few of the main essential-oil constituents appeared to be highly intercorrelated. Strong positive correlations were observed between α-pinene and camphene, camphene and camphor, as well as between cis-thujone and trans-thujone. Strong negative correlations were evidenced between cis-thujone and α-pinene, cis-thujone and champhene, cis-thujone and camphor, as well as between trans-thujone and camphene. Multivariate analyses allowed the grouping of the populations into three distinct chemotypes, i.e., Chemotype A, rich in total thujones, Chemotype B, with intermediate contents of thujones, α-pinene, camphene, and camphor and high borneol contents, and Chemotype C, rich in camphor, camphene, and α-pinene. The chemotypes did not significantly differ in the total essential-oil content and the cis/trans-thujone ratio. Copyright © 2014 Verlag Helvetica Chimica Acta AG, Zürich.

Intraspecific differences in plant chemotype determine the structure of arthropod food webs.

PubMed

Bálint, János; Zytynska, Sharon E; Salamon, Rozália Veronika; Mehrparvar, Mohsen; Weisser, Wolfgang W; Schmitz, Oswald J; Benedek, Klára; Balog, Adalbert

2016-03-01

It is becoming increasingly appreciated that the structure and functioning of ecological food webs are controlled by the nature and level of plant chemicals. It is hypothesized that intraspecific variation in plant chemical resistance, in which individuals of a host-plant population exhibit genetic differences in their chemical contents (called 'plant chemotypes'), may be an important determinant of variation in food web structure and functioning. We evaluated this hypothesis using field assessments and plant chemical assays in the tansy plant Tanacetum vulgare L. (Asteraceae). We examined food webs in which chemotypes of tansy plants are the resource for two specialized aphids, their predators and mutualistic ants. The density of the ant-tended aphid Metopeurum fuscoviride was significantly higher on particular chemotypes (borneol) than others. Clear chemotype preferences between predators were also detected. Aphid specialist seven-spotted ladybird beetles (Coccinella septempunctata) were more often found on camphor plants, while significantly higher numbers of the polyphagous nursery web spider (Pisaura mirabilis) were observed on borneol plants. The analysis of plant chemotype effects on the arthropod community clearly demonstrates a range of possible outcomes between plant-aphid-predator networks. The findings help to offer a deeper insight into how one important factor--plant chemical content--influences which species coexist within a food web on a particular host plant and the nature of their trophic linkages.

Soft Coral Sarcophyton (Cnidaria: Anthozoa: Octocorallia) Species Diversity and Chemotypes

PubMed Central

Aratake, Satoe; Tomura, Tomohiko; Saitoh, Seikoh; Yokokura, Ryouma; Kawanishi, Yuichi; Shinjo, Ryuichi; Reimer, James Davis; Tanaka, Junichi; Maekawa, Hideaki

2012-01-01

Research on the soft coral genus Sarcophyton extends over a wide range of fields, including marine natural products and the isolation of a number of cembranoid diterpenes. However, it is still unknown how soft corals produce this diverse array of metabolites, and the relationship between soft coral diversity and cembranoid diterpene production is not clear. In order to understand this relationship, we examined Sarcophyton specimens from Okinawa, Japan, by utilizing three methods: morphological examination of sclerites, chemotype identification, and phylogenetic examination of both Sarcophyton (utilizing mitochondrial protein-coding genes MutS homolog: msh1) and their endosymbiotic Symbiodinium spp. (utilizing nuclear internal transcribed spacer of ribosomal DNA: ITS- rDNA). Chemotypes, molecular phylogenetic clades, and sclerites of Sarcophyton trocheliophorum specimens formed a clear and distinct group, but the relationships between chemotypes, molecular phylogenetic clade types and sclerites of the most common species, Sarcophyton glaucum, was not clear. S. glaucum was divided into four clades. A characteristic chemotype was observed within one phylogenetic clade of S. glaucum. Identities of symbiotic algae Symbiodinium spp. had no apparent relation to chemotypes of Sarcophyton spp. This study demonstrates that the complex results observed for S. glaucum are due to the incomplete and complex taxonomy of this species group. Our novel method of identification should help contribute to classification and taxonomic reassessment of this diverse soft coral genus. PMID:22272344

Soft coral Sarcophyton (Cnidaria: Anthozoa: Octocorallia) species diversity and chemotypes.

PubMed

Aratake, Satoe; Tomura, Tomohiko; Saitoh, Seikoh; Yokokura, Ryouma; Kawanishi, Yuichi; Shinjo, Ryuichi; Reimer, James Davis; Tanaka, Junichi; Maekawa, Hideaki

2012-01-01

Research on the soft coral genus Sarcophyton extends over a wide range of fields, including marine natural products and the isolation of a number of cembranoid diterpenes. However, it is still unknown how soft corals produce this diverse array of metabolites, and the relationship between soft coral diversity and cembranoid diterpene production is not clear. In order to understand this relationship, we examined Sarcophyton specimens from Okinawa, Japan, by utilizing three methods: morphological examination of sclerites, chemotype identification, and phylogenetic examination of both Sarcophyton (utilizing mitochondrial protein-coding genes MutS homolog: msh1) and their endosymbiotic Symbiodinium spp. (utilizing nuclear internal transcribed spacer of ribosomal DNA: ITS- rDNA). Chemotypes, molecular phylogenetic clades, and sclerites of Sarcophyton trocheliophorum specimens formed a clear and distinct group, but the relationships between chemotypes, molecular phylogenetic clade types and sclerites of the most common species, Sarcophyton glaucum, was not clear. S. glaucum was divided into four clades. A characteristic chemotype was observed within one phylogenetic clade of S. glaucum. Identities of symbiotic algae Symbiodinium spp. had no apparent relation to chemotypes of Sarcophyton spp. This study demonstrates that the complex results observed for S. glaucum are due to the incomplete and complex taxonomy of this species group. Our novel method of identification should help contribute to classification and taxonomic reassessment of this diverse soft coral genus.

Effect of different liming levels on the biomass production and essential oil extraction yield of Cunila galioides Benth.

PubMed

Mossi, A J; Pauletti, G F; Rota, L; Echeverrigaray, S; Barros, I B I; Oliveira, J V; Paroul, N; Cansian, R L

2012-11-01

Poejo is an aromatic and medicinal plant native to highland areas of south Brazil, in acid soils with high Al3+ concentration. The main objective of the present work was to evaluate the effect of liming on the extraction yield of essential oil of three chemotypes of poejo (Cunila galioides Benth). For this purpose, the experiments were performed in a greenhouse, using 8-litre pots. The treatments were four dosages of limestone (0, 3.15, 12.5, and 25 g.L(-1)) and a completely random experimental design was used, with four replications and three chemotypes, set up in a 3 × 4 factorial arrangement. The parameters evaluated were dry weight of aerial parts, essential oil content and chemical composition of essential oil. Results showed that liming affects the biomass production, essential oil yield and chemical composition, with cross interaction verified between chemotype and limestone dosage. For the higher dosage lower biomass production, lower yield of essential oil as well as the lowest content of citral (citral chemotype) and limonene (menthene chemotype) was observed. In the ocimene chemotype, no liming influence was observed on the essential oil yield and on the content of major compounds. The dosage of 3.15 g.L(-1) can be considered the best limestone dosage for the production of poejo for the experimental conditions evaluated.

Structure guided optimization of a fragment hit to imidazopyridine inhibitors of PI3K.

PubMed

Pecchi, Sabina; Ni, Zhi-Jie; Han, Wooseok; Smith, Aaron; Lan, Jiong; Burger, Matthew; Merritt, Hanne; Wiesmann, Marion; Chan, John; Kaufman, Susan; Knapp, Mark S; Janssen, Johanna; Huh, Kay; Voliva, Charles F

2013-08-15

PI3 kinases are a family of lipid kinases mediating numerous cell processes such as proliferation, migration and differentiation. The PI3 Kinase pathway is often de-regulated in cancer through PI3Kα overexpression, gene amplification, mutations and PTEN phosphatase deletion. PI3K inhibitors represent therefore an attractive therapeutic modality for cancer treatment. Herein we describe how the potency of a benzothiazole fragment hit was quickly improved based on structural information and how this early chemotype was further optimized through scaffold hopping. This effort led to the identification of a series of 2-acetamido-5-heteroaryl imidazopyridines showing potent in vitro activity against all class I PI3Ks and attractive pharmacokinetic properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

Discovery of potential ZAP-70 kinase inhibitors: pharmacophore design, database screening and docking studies.

PubMed

Sanam, Ramadevi; Vadivelan, S; Tajne, Sunita; Narasu, Lakshmi; Rambabu, G; Jagarlapudi, Sarma A R P

2009-12-01

The best ZAP-70 inhibitor model consists of four-pharmacophore features, (1) one hydrogen bond acceptor, (2) one hydrogen bond donor (3) one hydrophobic aliphatic and (4) one hydrophobic aromatic features. This model was validated against 110 known ZAP-70 inhibitors with a correlation of 0.902 as well as enrichment factor of 1.61 against a maximum value of 2. This model picked 4094 hits from a database of 238,819 molecules while 358 molecules were indicated as highly active. Subsequently, docking studies were performed on the hits and novel series of potent leads were suggested based on the interactions energy between ZAP-70 and the putative inhibitors which validated not only the virtual screening potential of the model but also identified the possible new Chemotypes.

The relationship between genetic and chemotypic diversity in American ginseng (Panax quinquefolius L.).

PubMed

Schlag, Erin M; McIntosh, Marla S

2013-09-01

Ginseng is one of the world's most important herbals used as an adaptogen and a cure for an impressively large range of ailments. Differences in the medicinal properties of ginseng roots have been attributed to variation in ginsenoside composition. In this study, the association between genetic and chemotypic profiles of wild and cultivated American ginseng (Panax quinquefolius L.) roots grown in Maryland was investigated. Ginseng roots were classified into chemotypes based on their relative composition of Re and Rg1. Genetic profiles of these roots were determined from the analysis of 38 polymorphic RAPD markers and used for a cluster analysis of genetic similarities. The close correspondence between chemotype and genetic cluster provides the first DNA-based evidence for the genetic basis of ginsenoside composition. Results of this research are significant for plant breeding and conservation, phytochemical research, and clinical and pharmacological studies. Also, the correlation between RAPD markers and chemotype indicates the potential to use RAPD markers as a reliable and practical method for identification and certification of ginseng roots. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bis-benzimidazole hits against Naegleria fowleri discovered with new high-throughput screens.

PubMed

Rice, Christopher A; Colon, Beatrice L; Alp, Mehmet; Göker, Hakan; Boykin, David W; Kyle, Dennis E

2015-04-01

Naegleria fowleri is a pathogenic free-living amoeba (FLA) that causes an acute fatal disease known as primary amoebic meningoencephalitis (PAM). The major problem for infections with any pathogenic FLA is a lack of effective therapeutics, since PAM has a case mortality rate approaching 99%. Clearly, new drugs that are potent and have rapid onset of action are needed to enhance the treatment regimens for PAM. Diamidines have demonstrated potency against multiple pathogens, including FLA, and are known to cross the blood-brain barrier to cure other protozoan diseases of the central nervous system. Therefore, amidino derivatives serve as an important chemotype for discovery of new drugs. In this study, we validated two new in vitro assays suitable for medium- or high-throughput drug discovery and used these for N. fowleri. We next screened over 150 amidino derivatives of multiple structural classes and identified two hit series with nM potency that are suitable for further lead optimization as new drugs for this neglected disease. These include both mono- and diamidino derivatives, with the most potent compound (DB173) having a 50% inhibitory concentration (IC50) of 177 nM. Similarly, we identified 10 additional analogues with IC50s of <1 μM, with many of these having reasonable selectivity indices. The most potent hits were >500 times more potent than pentamidine. In summary, the mono- and diamidino derivatives offer potential for lead optimization to develop new drugs to treat central nervous system infections with N. fowleri. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Exploring pharmacological activities and signaling of morphinans substituted in position 6 as potent agonists interacting with the μ opioid receptor

PubMed Central

2014-01-01

Background Opioid analgesics are the most effective drugs for the treatment of moderate to severe pain. However, they also produce several adverse effects that can complicate pain management. The μ opioid (MOP) receptor, a G protein-coupled receptor, is recognized as the opioid receptor type which primarily mediates the pharmacological actions of clinically used opioid agonists. The morphinan class of analgesics including morphine and oxycodone are of main importance as therapeutically valuable drugs. Though the natural alkaloid morphine contains a C-6-hydroxyl group and the semisynthetic derivative oxycodone has a 6-carbonyl function, chemical approaches have uncovered that functionalizing position 6 gives rise to a range of diverse activities. Hence, position 6 of N-methylmorphinans is one of the most manipulated sites, and is established to play a key role in ligand binding at the MOP receptor, efficacy, signaling, and analgesic potency. We have earlier reported on a chemically innovative modification in oxycodone resulting in novel morphinans with 6-acrylonitrile incorporated substructures. Results This study describes in vitro and in vivo pharmacological activities and signaling of new morphinans substituted in position 6 with acrylonitrile and amido functions as potent agonists and antinociceptive agents interacting with MOP receptors. We show that the presence of a 6-cyano group in N-methylmorphinans has a strong influence on the binding to the opioid receptors and post-receptor signaling. One 6-cyano-N-methylmorphinan of the series was identified as the highest affinity and most selective MOP agonist, and very potent in stimulating G protein coupling and intracellular calcium release through the MOP receptor. In vivo, this MOP agonist showed to be greatly effective against thermal and chemical nociception in mice with marked increased antinociceptive potency than the lead molecule oxycodone. Conclusion Development of such novel chemotypes by targeting position 6 provides valuable insights on ligand-receptor interaction and molecular mode of action, and may aid in identification of opioid therapeutics with enhanced analgesic properties and fewer undesirable effects. PMID:25059282

4(1H)-Pyridone and 4(1H)-Quinolone Derivatives as Antimalarials with Erythrocytic, Exoerythrocytic, and Transmission Blocking Activities

PubMed Central

Monastyrskyi, Andrii; Kyle, Dennis E.; Manetsch, Roman

2015-01-01

Infectious diseases are the second leading cause of deaths in the world with malaria being responsible for approximately the same amount of deaths as cancer in 2012. Despite the success in malaria prevention and control measures decreasing the disease mortality rate by 45% since 2000, the development of single-dose therapeutics with radical cure potential is required to completely eradicate this deadly condition. Targeting multiple stages of the malaria parasite is becoming a primary requirement for new candidates in antimalarial drug discovery and development. Recently, 4(1H)-pyridone, 4(1H)-quinolone, 1,2,3,4-tetrahydroacridone, and phenoxyethoxy-4(1H)-quinolone chemotypes have been shown to be antimalarials with blood stage activity, liver stage activity, and transmission blocking activity. Advancements in structure-activity relationship and structure-property relationship studies, biological evaluation in vitro and in vivo, as well as pharmacokinetics of the 4(1H)-pyridone and 4(1H)-quinolone chemotypes will be discussed. PMID:25116582

Identification and prioritization of novel anti-Wolbachia chemotypes from screening a 10,000-compound diversity library

PubMed Central

Johnston, Kelly L.; Cook, Darren A. N.; Berry, Neil G.; David Hong, W.; Clare, Rachel H.; Goddard, Megan; Ford, Louise; Nixon, Gemma L.; O’Neill, Paul M.; Ward, Stephen A.; Taylor, Mark J.

2017-01-01

Lymphatic filariasis and onchocerciasis are two important neglected tropical diseases (NTDs) that cause severe disability. Control efforts are hindered by the lack of a safe macrofilaricidal drug. Targeting the Wolbachia bacterial endosymbionts in these parasites with doxycycline leads to a macrofilaricidal outcome, but protracted treatment regimens and contraindications restrict its widespread implementation. The Anti-Wolbachia consortium aims to develop improved anti-Wolbachia drugs to overcome these barriers. We describe the first screening of a large, diverse compound library against Wolbachia. This whole-organism screen, streamlined to reduce bottlenecks, produced a hit rate of 0.5%. Chemoinformatic analysis of the top 50 hits led to the identification of six structurally diverse chemotypes, the disclosure of which could offer interesting avenues of investigation to other researchers active in this field. An example of hit-to-lead optimization is described to further demonstrate the potential of developing these high-quality hit series as safe, efficacious, and selective anti-Wolbachia macrofilaricides. PMID:28959730

Citral and carvone chemotypes from the essential oils of Colombian Lippia alba (Mill.) N.E. Brown: composition, cytotoxicity and antifungal activity.

PubMed

Mesa-Arango, Ana Cecilia; Montiel-Ramos, Jehidys; Zapata, Bibiana; Durán, Camilo; Betancur-Galvis, Liliana; Stashenko, Elena

2009-09-01

Two essential oils of Lippia alba (Mill.) N.E. Brown (Verbenacea), the carvone and citral chemotypes and 15 of their compounds were evaluated to determine cytotoxicity and antifungal activity. Cytotoxicity assays for both the citral and carvone chemotypes were carried out with tetrazolium-dye, which showed a dose-dependent cytotoxic effect against HeLa cells. Interestingly, this effect on the evaluated cells (HeLa and the non-tumoural cell line, Vero) was lower than that of commercial citral alone. Commercial citral showed the highest cytotoxic activity on HeLa cells. The antifungal activity was evaluated against Candida parapsilosis, Candida krusei, Aspergillus flavus and Aspergillus fumigatus strains following the standard protocols, Antifungal Susceptibility Testing Subcommittee of the European Committee on Antibiotic Susceptibility Testing and CLSI M38-A. Results demonstrated that the most active essential oil was the citral chemotype, with geometric means-minimal inhibitory concentration (GM-MIC) values of 78.7 and 270.8 microg/mL for A. fumigatus and C. krusei, respectively. Commercial citral showed an antifungal activity similar to that of the citral chemotype (GM-MIC values of 62.5 microg/mL for A. fumigatus and 39.7 microg/mL for C. krusei). Although the citronellal and geraniol were found in lower concentrations in the citral chemotype, they had significant antifungal activity, with GM-MIC values of 49.6 microg/mL for C. krusei and 176.8 microg/mL for A. fumigatus.

Human bactericidal/permeability-increasing protein and a recombinant NH2-terminal fragment cause killing of serum-resistant gram-negative bacteria in whole blood and inhibit tumor necrosis factor release induced by the bacteria.

PubMed Central

Weiss, J; Elsbach, P; Shu, C; Castillo, J; Grinna, L; Horwitz, A; Theofan, G

1992-01-01

The bactericidal/permeability-increasing protein (BPI) of neutrophils and BPI fragments neutralize the effects of isolated Gram-negative bacterial lipopolysaccharides both in vitro and in vivo. Since endotoxin most commonly enters the host as constituents of invading Gram-negative bacteria, we raised the question: Can BPI and its bioactive fragments also protect against whole bacteria? To determine whether the bactericidal and endotoxin-neutralizing activities of BPI/fragments are expressed when Gram-negative bacteria are introduced to the complex environment of whole blood we examined the effects of added BPI and proteolytically prepared and recombinant NH2-terminal fragments on: (a) the fate of serum-resistant encapsulated Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa that survive the antibacterial actions of whole blood and (b) the ability of these bacteria to trigger cytokine release. Added BPI in nanomolar concentrations killed each of three encapsulated strains of E. coli and in closely parallel fashion inhibited tumor necrosis factor (TNF) release. Holo-BPI and its NH2-terminal fragment were equipotent toward a rough LPS chemotype K1-encapsulated strain, but the fragment was substantially more potent than holo-BPI toward two encapsulated smooth LPS chemotype strains. TNF release induced by K. pneumoniae and P. aeruginosa was also inhibited by both holo-BPI and fragment but, at the protein concentrations tested, P. aeruginosa was killed only by the fragment and K. pneumoniae was not killed by either protein. The bactericidal action of BPI/fragment toward E. coli is inhibited by C7-depleted serum, but accelerated by normal serum, indicating that BPI, acting in synergy with late complement components, enhances extracellular killing of serum-resistant bacteria. Thus, BPI and an even more potent NH2-terminal fragment may protect against Gram-negative bacteria in the host by blocking bacterial proliferation as well as endotoxin-mediated effects, not only as components of the intracellular antibacterial arsenal of the neutrophil, but also as potentially therapeutic extracellular agents. PMID:1522221

Human bactericidal/permeability-increasing protein and a recombinant NH2-terminal fragment cause killing of serum-resistant gram-negative bacteria in whole blood and inhibit tumor necrosis factor release induced by the bacteria.

PubMed

Weiss, J; Elsbach, P; Shu, C; Castillo, J; Grinna, L; Horwitz, A; Theofan, G

1992-09-01

The bactericidal/permeability-increasing protein (BPI) of neutrophils and BPI fragments neutralize the effects of isolated Gram-negative bacterial lipopolysaccharides both in vitro and in vivo. Since endotoxin most commonly enters the host as constituents of invading Gram-negative bacteria, we raised the question: Can BPI and its bioactive fragments also protect against whole bacteria? To determine whether the bactericidal and endotoxin-neutralizing activities of BPI/fragments are expressed when Gram-negative bacteria are introduced to the complex environment of whole blood we examined the effects of added BPI and proteolytically prepared and recombinant NH2-terminal fragments on: (a) the fate of serum-resistant encapsulated Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa that survive the antibacterial actions of whole blood and (b) the ability of these bacteria to trigger cytokine release. Added BPI in nanomolar concentrations killed each of three encapsulated strains of E. coli and in closely parallel fashion inhibited tumor necrosis factor (TNF) release. Holo-BPI and its NH2-terminal fragment were equipotent toward a rough LPS chemotype K1-encapsulated strain, but the fragment was substantially more potent than holo-BPI toward two encapsulated smooth LPS chemotype strains. TNF release induced by K. pneumoniae and P. aeruginosa was also inhibited by both holo-BPI and fragment but, at the protein concentrations tested, P. aeruginosa was killed only by the fragment and K. pneumoniae was not killed by either protein. The bactericidal action of BPI/fragment toward E. coli is inhibited by C7-depleted serum, but accelerated by normal serum, indicating that BPI, acting in synergy with late complement components, enhances extracellular killing of serum-resistant bacteria. Thus, BPI and an even more potent NH2-terminal fragment may protect against Gram-negative bacteria in the host by blocking bacterial proliferation as well as endotoxin-mediated effects, not only as components of the intracellular antibacterial arsenal of the neutrophil, but also as potentially therapeutic extracellular agents.

Chemical methodology as a source of small-molecule checkpoint inhibitors and heat shock protein 70 (Hsp70) modulators.

PubMed

Huryn, Donna M; Brodsky, Jeffrey L; Brummond, Kay M; Chambers, Peter G; Eyer, Benjamin; Ireland, Alex W; Kawasumi, Masaoki; Laporte, Matthew G; Lloyd, Kayla; Manteau, Baptiste; Nghiem, Paul; Quade, Bettina; Seguin, Sandlin P; Wipf, Peter

2011-04-26

Unique chemical methodology enables the synthesis of innovative and diverse scaffolds and chemotypes and allows access to previously unexplored "chemical space." Compound collections based on such new synthetic methods can provide small-molecule probes of proteins and/or pathways whose functions are not fully understood. We describe the identification, characterization, and evolution of two such probes. In one example, a pathway-based screen for DNA damage checkpoint inhibitors identified a compound, MARPIN (ATM and ATR pathway inhibitor) that sensitizes p53-deficient cells to DNA-damaging agents. Modification of the small molecule and generation of an immobilized probe were used to selectively bind putative protein target(s) responsible for the observed activity. The second example describes a focused library approach that relied on tandem multicomponent reaction methodologies to afford a series of modulators of the heat shock protein 70 (Hsp70) molecular chaperone. The synthesis of libraries based on the structure of MAL3-101 generated a collection of chemotypes, each modulating Hsp70 function, but exhibiting divergent pharmacological activities. For example, probes that compromise the replication of a disease-associated polyomavirus were identified. These projects highlight the importance of chemical methodology development as a source of small-molecule probes and as a drug discovery starting point.

Chemical methodology as a source of small-molecule checkpoint inhibitors and heat shock protein 70 (Hsp70) modulators

PubMed Central

Huryn, Donna M.; Brodsky, Jeffrey L.; Brummond, Kay M.; Chambers, Peter G.; Eyer, Benjamin; Ireland, Alex W.; Kawasumi, Masaoki; LaPorte, Matthew G.; Lloyd, Kayla; Manteau, Baptiste; Nghiem, Paul; Quade, Bettina; Seguin, Sandlin P.; Wipf, Peter

2011-01-01

Unique chemical methodology enables the synthesis of innovative and diverse scaffolds and chemotypes and allows access to previously unexplored “chemical space.” Compound collections based on such new synthetic methods can provide small-molecule probes of proteins and/or pathways whose functions are not fully understood. We describe the identification, characterization, and evolution of two such probes. In one example, a pathway-based screen for DNA damage checkpoint inhibitors identified a compound, MARPIN (ATM and ATR pathway inhibitor) that sensitizes p53-deficient cells to DNA-damaging agents. Modification of the small molecule and generation of an immobilized probe were used to selectively bind putative protein target(s) responsible for the observed activity. The second example describes a focused library approach that relied on tandem multicomponent reaction methodologies to afford a series of modulators of the heat shock protein 70 (Hsp70) molecular chaperone. The synthesis of libraries based on the structure of MAL3-101 generated a collection of chemotypes, each modulating Hsp70 function, but exhibiting divergent pharmacological activities. For example, probes that compromise the replication of a disease-associated polyomavirus were identified. These projects highlight the importance of chemical methodology development as a source of small-molecule probes and as a drug discovery starting point. PMID:21502524

The Chemical Diversity of Lantana camara: Analyses of Essential Oil Samples from Cuba, Nepal, and Yemen.

PubMed

Satyal, Prabodh; Crouch, Rebecca A; Monzote, Lianet; Cos, Paul; Awadh Ali, Nasser A; Alhaj, Mehdi A; Setzer, William N

2016-03-01

The aerial parts of Lantana camara L. were collected from three different geographical locations: Artemisa (Cuba), Biratnagar (Nepal), and Sana'a (Yemen). The essential oils were obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry. A cluster analysis of 39 L. camara essential oil compositions revealed eight major chemotypes: β-caryophyllene, germacrene D, ar-curcumene/zingiberene, γ-curcumen-15-al/epi-β-bisabolol, (E)-nerolidol, davanone, eugenol/alloaromadendrene, and carvone. The sample from Cuba falls into the group dominated by (E)-nerolidol, the sample from Nepal is a davanone chemotype, and the sample from Yemen belongs to the β-caryophyllene chemotype. The chemical composition of L. camara oil plays a role in the biological activity; the β-caryophyllene and (E)-nerolidol chemotypes showed antimicrobial and cytotoxic activities. © 2016 Verlag Helvetica Chimica Acta AG, Zürich.

Cymbopogon species; ethnopharmacology, phytochemistry and the pharmacological importance.

PubMed

Avoseh, Opeyemi; Oyedeji, Opeoluwa; Rungqu, Pamela; Nkeh-Chungag, Benedicta; Oyedeji, Adebola

2015-04-23

Cymbopogon genus is a member of the family of Gramineae which are herbs known worldwide for their high essential oil content. They are widely distributed across all continents where they are used for various purposes. The commercial and medicinal uses of the various species of Cymbopogon are well documented. Ethnopharmacology evidence shows that they possess a wide array of properties that justifies their use for pest control, in cosmetics and as anti-inflammation agents. These plants may also hold promise as potent anti-tumor and chemopreventive drugs. The chemo-types from this genus have been used as biomarkers for their identification and classification. Pharmacological applications of Cymbopogon citratus are well exploited, though studies show that other species may also useful pharmaceutically. Hence this literature review intends to discuss these species and explore their potential economic importance.

Efficacy of Withania somnifera chemotypes NMITLI - 101R, 118R and Withaferin A against experimental visceral leishmaniasis.

PubMed

Tripathi, C D P; Gupta, R; Kushawaha, P K; Mandal, C; Misra Bhattacharya, S; Dube, A

2014-06-01

The immunoprophylactic and therapeutic potentials of root extracts of Withania somnifera chemotypes (NMITLI-118, NMITLI-101) and pure withanolide-withaferin A was investigated against Leishmania donovani infection in hamsters. The naive animals, fed orally with immunostimulatory doses of chemotypes 101R, 118R (10 and 3 mg/kg) and withaferin A (9 and 3 mg/kg) for five consecutive days and challenged with Leishmania parasites on day 6, were euthanized on days 30 and 45 p.c. for the assessment of parasite clearance, real-time analysis of mRNAs of Th1/Th2 cytokines (IFN-γ, IL-12, TNF-α, iNOS/IL-4, IL-10 and TGF-β), NO production, reactive oxygen species (ROS) generation, lymphocyte transformation test and antibody responses. By day 45 p.c., there was a significant increase in the mRNA expression of iNOS, IFN-γ, IL-12 and TNF-α but decrease in IL-4, IL-10 and TGF-β, an enhanced Leishmania-specific LTT response as well as ROS, NO and antileishmanial IgG2 levels in 101R-treated hamsters followed by 118R- and withaferin A-treated ones, respectively. When these chemotypes were given to L. donovani-infected hamsters at different doses, there was moderate therapeutic efficacy of chemotype 101R (~50%) at 30 mg/kg × 5 followed by the other two. The results established that the 101R is the most potential chemotype and can be evaluated for combination therapy along with available antileishmanials. © 2014 John Wiley & Sons Ltd.

Mentha suaveolens Ehrh. Chemotypes in Eastern Iberian Peninsula: Essential Oil Variation and Relation with Ecological Factors.

PubMed

Llorens-Molina, Juan Antonio; Rivera Seclén, Cynthia Fiorella; Vacas Gonzalez, Sandra; Boira Tortajada, Herminio

2017-12-01

Essential oil (EO) extracts coming from two representative populations of Mentha suaveolens Ehrh. subesp. suaveolens in Eastern Iberian Peninsula were analyzed by gas chromatography coupled with mass spectrometry and flame ion detector. Plant sampling was carried out in the morning and evening in order to study diurnal variation in EO profiles. Likewise, leaves and inflorescences were analyzed separately. Two chemotypes corresponding to each one of the populations were identified, with piperitenone oxide (35.2 - 74.3%) and piperitone oxide (83.9 - 91.3%), respectively, as major compounds. Once different chemotypes were identified, canonical correspondence analysis was employed to evaluate the effect of the bioclimatic and edaphic factors recorded in each location on the observed differences. Statistical analysis suggested that these chemotypes were closely related to specific environmental factors, mainly the bioclimatic ones. Concretely, piperitenone oxide chemotype can be associated to supramediterranean bioclimatic conditions and soils with major salinity and water field capacity. On the other hand, the most volatile fraction (hydrocarbon monoterpenes) reached its higher level in the morning; specifically, a noticeable amount of limonene was found in morning samples of flowers (4.8 - 10.6%). This fact can be related to ecological role of volatile compounds in order to attract pollinator insects. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Combining on-chip synthesis of a focused combinatorial library with computational target prediction reveals imidazopyridine GPCR ligands.

PubMed

Reutlinger, Michael; Rodrigues, Tiago; Schneider, Petra; Schneider, Gisbert

2014-01-07

Using the example of the Ugi three-component reaction we report a fast and efficient microfluidic-assisted entry into the imidazopyridine scaffold, where building block prioritization was coupled to a new computational method for predicting ligand-target associations. We identified an innovative GPCR-modulating combinatorial chemotype featuring ligand-efficient adenosine A1/2B and adrenergic α1A/B receptor antagonists. Our results suggest the tight integration of microfluidics-assisted synthesis with computer-based target prediction as a viable approach to rapidly generate bioactivity-focused combinatorial compound libraries with high success rates. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inhibition of Mutated Isocitrate Dehydrogenase 1 in Cancer.

PubMed

Wu, Fangrui; Cheng, Gang; Yao, Yuan; Kogiso, Mari; Jiang, Hong; Li, Xiao-Nan; Song, Yongcheng

2018-05-23

R132H mutation of isocitrate dehydrogenase 1 (IDH1) are found in ~75% of low-grade gliomas and secondary glioblastomas as well as in several other types of cancer. More chemotypes of inhibitors of IDH1(R132H) are therefore needed. To develop a new class of IDH1(R132H) inhibitors as potent antitumor agents. A biochemical assay was developed to find inhibitors of IDH1(R132H) mutant enzyme. Chemical synthesis and structure activity relationship studies were used to find compounds with improved potency. Antitumor activities of selected compounds were evaluated. A series of aromatic sulfonamide compounds were found to be novel, potent inhibitors of IDH1(R132H) with Ki values as low as 0.6 µM. Structure activity relationships of these compounds are discussed. Enzyme kinetics studies showed that one compound is a competitive inhibitor against the substrate α-KG and a non-competitive inhibitor against the cofactor NADPH. Several inhibitors were found to have no activity against wild-type IDH1, showing a high selectivity. Two potent inhibitors exhibited strong activity against proliferation of BT142 glioma cells with IDH1 R132H mutation, while these compounds did not significantly affect growth of glioma cells without IDH1 mutation. This novel series of IDH1(R132H) inhibitors have potential to be further developed for the treatment of glioma with IDH1 mutation. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Chemotypes and Biomarkers of Seven Species of New Caledonian Liverworts from the Bazzanioideae Subfamily.

PubMed

Métoyer, Benjamin; Lebouvier, Nicolas; Hnawia, Edouard; Herbette, Gaëtan; Thouvenot, Louis; Asakawa, Yoshinori; Nour, Mohammed; Raharivelomanana, Phila

2018-06-05

Volatile components of seven species of the Bazzanioideae sub-family (Lepidoziaceae) native to New Caledonia, including three endemic species ( Bazzania marginata , Acromastigum caledonicum and A. tenax ), were analyzed by GC-FID-MS in order to index these plants to known or new chemotypes. Detected volatile constituents in studied species were constituted mainly by sesquiterpene, as well as diterpene compounds. All so-established compositions cannot successfully index some of them to known chemotypes but afforded the discovery of new chemotypes such as cuparane/fusicoccane. The major component of B. francana was isolated and characterized as a new zierane-type sesquiterpene called ziera-12(13),10(14)-dien-5-ol ( 23 ). In addition, qualitative intraspecies variations of chemical composition were very important particularly for B. francana which possessed three clearly defined different compositions. We report here also the first phytochemical investigation of Acromastigum species. Moreover, crude diethyl ether extract of B. vitatta afforded a new bis(bibenzyl) called vittatin ( 51 ), for which a putative biosynthesis was suggested.

Identification of the chemotypes of Ocimum forskolei and Ocimum basilicum by NMR spectroscopy.

PubMed

Fatope, Majekodunmi O; Marwah, Ruchi G; Al Hadhrami, Nabil M; Onifade, Anthony K; Williams, John R

2008-11-01

The chemotypes of Ocimum forskolei Benth and Ocimum basilicum L. growing wild in Oman have been established by (13)C-NMR analyses of the vegetative and floral oils of the plants. The chemotypes, estragole for O. forskolei and linalool for O. basilicum, suggested by (13)C-NMR fingerprinting were also confirmed by GC-FID and GC/MS analyses. The oil of O. forskolei demonstrated better activities against bacteria and dermatophytes. The significance of the presence of estragole and linalool in the volatile oils of plants whose fragrances are traditionally inhaled, added to food, or rubbed on the skin are discussed.

Performance of multiple docking and refinement methods in the pose prediction D3R prospective Grand Challenge 2016

NASA Astrophysics Data System (ADS)

Fradera, Xavier; Verras, Andreas; Hu, Yuan; Wang, Deping; Wang, Hongwu; Fells, James I.; Armacost, Kira A.; Crespo, Alejandro; Sherborne, Brad; Wang, Huijun; Peng, Zhengwei; Gao, Ying-Duo

2018-01-01

We describe the performance of multiple pose prediction methods for the D3R 2016 Grand Challenge. The pose prediction challenge includes 36 ligands, which represent 4 chemotypes and some miscellaneous structures against the FXR ligand binding domain. In this study we use a mix of fully automated methods as well as human-guided methods with considerations of both the challenge data and publicly available data. The methods include ensemble docking, colony entropy pose prediction, target selection by molecular similarity, molecular dynamics guided pose refinement, and pose selection by visual inspection. We evaluated the success of our predictions by method, chemotype, and relevance of publicly available data. For the overall data set, ensemble docking, visual inspection, and molecular dynamics guided pose prediction performed the best with overall mean RMSDs of 2.4, 2.2, and 2.2 Å respectively. For several individual challenge molecules, the best performing method is evaluated in light of that particular ligand. We also describe the protein, ligand, and public information data preparations that are typical of our binding mode prediction workflow.

Low-basicity 5-HT7 Receptor Agonists Synthesized Using the van Leusen Multicomponent Protocol.

PubMed

Hogendorf, Adam S; Hogendorf, Agata; Kurczab, Rafał; Satała, Grzegorz; Lenda, Tomasz; Walczak, Maria; Latacz, Gniewomir; Handzlik, Jadwiga; Kieć-Kononowicz, Katarzyna; Wierońska, Joanna M; Woźniak, Monika; Cieślik, Paulina; Bugno, Ryszard; Staroń, Jakub; Bojarski, Andrzej J

2017-05-04

A series of 5-aryl-1-alkylimidazole derivatives was synthesized using the van Leusen multicomponent reaction. The chemotype is the first example of low-basicity scaffolds exhibiting high affinity for 5-HT 7 receptor together with agonist function. The chosen lead compounds 3-(1-ethyl-1H-imidazol-5-yl)-5-iodo-1H-indole (AGH-107, 1o, K i 5-HT7  = 6 nM, EC 50  = 19 nM, 176-fold selectivity over 5-HT 1A R) and 1e (5-methoxy analogue, K i 5-HT7  = 30 nM, EC 50  = 60 nM) exhibited high selectivity over related CNS targets, high metabolic stability and low toxicity in HEK-293 and HepG2 cell cultures. A rapid absorption to the blood, high blood-brain barrier permeation and a very high peak concentration in the brain (C max  = 2723 ng/g) were found for 1o after i.p. (5 mg/kg) administration in mice. The compound was found active in novel object recognition test in mice, at 0.5, 1 and 5 mg/kg. Docking to 5-HT 7 R homology models indicated a plausible binding mode which explain the unusually high selectivity over the related CNS targets. Halogen bond formation between the most potent derivatives and the receptor is consistent with both the docking results and SAR. 5-Chlorine, bromine and iodine substitution resulted in a 13, 27 and 89-fold increase in binding affinities, respectively, and in enhanced 5-HT 1A R selectivity.

Hsp90 molecular chaperone inhibitors: Are we there yet?

PubMed Central

Neckers, Len; Workman, Paul

2011-01-01

Heat shock protein (Hsp) 90 is an ATP-dependent molecular chaperone exploited by malignant cells to support activated oncoproteins, including many cancer-associated kinases and transcription factors, and is essential for oncogenic transformation. Originally viewed with skepticism, Hsp90 inhibitors are now actively pursued by the pharmaceutical industry, with 17 agents having entered clinical trials. Hsp90’s druggability was established using the natural products geldanamycin and radicicol which mimic the unusual ATP structure adopted in the chaperone’s N-terminal nucleotide-binding pocket and cause potent and selective blockade of ATP binding/hydrolysis, inhibit chaperone function, deplete oncogenic clients, and demonstrate antitumor activity. Preclinical data with these natural products have heightened interest in Hsp90 as a drug target, and 17-allylamino-17-demethoxygeldanamycin (17-AAG, tanespimycin) has demonstrated clinical activity (as defined by RECIST criteria) in HER2+ breast cancer. Many optimized synthetic small molecule Hsp90 inhibitors from diverse chemotypes are now in clinical trials. We review the discovery and development of Hsp90 inhibitors and assess their future potential. There has been significant learning from experience in both the basic biology and the translational drug development around Hsp90, enhanced by the use of Hsp90 inhibitors as chemical probes. Success will likely lie in treating cancers addicted to particular driver oncogene products, such as HER2, ALK, EGFR and BRAF, that are sensitive Hsp90 clients, as well as in malignancies, especially multiple myeloma, where buffering of proteotoxic stress is critical for survival. We discuss approaches to enhancing the effectiveness of Hsp90 inhibitors and highlight new chaperone and stress response pathway targets, including HSF1 and Hsp70. PMID:22215907

In vitro antifungal activity of four chemotypes of Lippia alba (Verbenaceae) essential oils against Alternaria solani (Pleosporeaceae) isolates.

PubMed

Tomazoni, Elisa Z; Pansera, Márcia R; Pauletti, Gabriel F; Moura, Sidnei; Ribeiro, Rute T S; Schwambach, Joséli

2016-05-31

Several volatile natural compounds produced by plant secondary metabolism have been proven to present antimicrobial action, enabling their use in phytopathogen control. They also present low environmental impact when compared to conventional pesticides. Essential oils contain these compounds and can be found in several plant species, such as Lippia alba (Mill.) N.E. Brown (Verbenaceae). Essential oils of four chemotypes of L. alba, characterized by their major compounds, namely camphor, citral, linalool and camphor/1,8-cineole, were tested against the phytopathogen Alternaria solani Sorauer (Pleosporaceae), which causes early blight on tomatoes and is responsible for great economic losses regarding production. Essential oils antifungal action was tested in vitro using potato dextrose agar medium with essential oil concentrations at 0.1, 0.5, 1.0, 1.5 and 2.0 µL mL-1. The chemotype that had the best performance was citral, showing significant inhibition compared to the others, starting at the 0.5 µL mL-1 concentration. The essential oil belonging to the linalool chemotype was efficient starting at the 1.5 µL mL-1 concentration. Conversely, the camphor chemotype did not show any action against the phytopathogen. Moreover, the essential oils had no remarkable effect on tomato germination and growth. In conclusion, these essential oils presented fungicidal action against A. solani.

Heterocyclic HIV-protease inhibitors.

PubMed

Calugi, C; Guarna, A; Trabocchi, A

2013-01-01

In the panorama of HIV protease inhibitors (HIV PIs), many efforts have been devoted to the development of new compounds with reduced peptidic nature in order to improve pharmacokinetics and pharmacodynamics features. The introduction of cyclic scaffolds in the design of new chemical entities reduces flexibility and affords more rigid inhibitors. Specifically, common dipeptide isosteres are replaced by a central cyclic scaffold designed to address the key interactions with catalytic aspartic acids and residues belonging to the flap region of the active site. The current interest in cyclic chemotypes addressing key interactions of HIV protease is motivated by the different nature of interactions formed with the enzyme, although maintaining key structural resemblance to a peptide substrate, hopefully giving rise to novel HIV-1 PIs displaying an improved profile towards multidrug resistant strains. This approach has been demonstrated for Tipranavir, which is a potent FDA approved HIV-1 PI representing the most famous example of heterocyclic aspartic protease inhibitors.

Chemotaxonomic Characterization and in-Vitro Antimicrobial and Cytotoxic Activities of the Leaf Essential Oil of Curcuma longa Grown in Southern Nigeria

PubMed Central

Essien, Emmanuel E.; Newby, Jennifer Schmidt; Walker, Tameka M.; Setzer, William N.; Ekundayo, Olusegun

2015-01-01

Curcuma longa (turmeric) has been used in Chinese traditional medicine and Ayurvedic medicine for many years. Methods: The leaf essential oil of C. longa from southern Nigeria was obtained by hydrodistillation and analyzed by gas chromatography–mass spectrometry (GC-MS). The essential oil was screened for in vitro antibacterial, antifungal, and cytotoxic activities. The major components in C. longa leaf oil were ar-turmerone (63.4%), α-turmerone (13.7%), and β-turmerone (12.6%). A cluster analysis has revealed this to be a new essential oil chemotype of C. longa. The leaf oil showed notable antibacterial activity to Bacillus cereus and Staphylococcus aureus, antifungal activity to Aspergillus niger, and cytotoxic activity to Hs 578T (breast tumor) and PC-3 (prostate tumor) cells. The ar-turmerone-rich leaf essential oil of C. longa from Nigeria has shown potent biological activity and therapeutic promise. PMID:28930216

2-Aminomethylthieno[3,2-d]pyrimidin-4(3H)-ones bearing 3-methylpyrazole hinge binding moiety: Highly potent, selective, and time-dependent inhibitors of Cdc7 kinase.

PubMed

Kurasawa, Osamu; Homma, Misaki; Oguro, Yuya; Miyazaki, Tohru; Mori, Kouji; Uchiyama, Noriko; Iwai, Kenichi; Ohashi, Akihiro; Hara, Hideto; Yoshida, Sei; Cho, Nobuo

2017-07-15

In order to increase the success rate for developing new Cdc7 inhibitors for cancer therapy, we explored a new chemotype which can comply with the previously-constructed pharmacophore model. Substitution of a pyridine ring of a serendipitously-identified Cdc7 inhibitor 2b with a 3-methylpyrazole resulted in a 4-fold increase in potency and acceptable kinase selectivity, leading to the identification of thieno[3,2-d]pyrimidin-4(3H)-one as an alternative scaffold. Structure-activity relationship (SAR) study revealed that incorporation of a substituted aminomethyl group into the 2-position improved kinase selectivity. Indeed, a pyrrolidinylmethyl derivative 10c was a potent Cdc7 inhibitor (IC 50 =0.70nM) with high selectivity (Cdk2/Cdc7≥14,000, ROCK1/Cdc7=200). It should be noted that 10c exhibited significant time-dependent Cdc7 inhibition with slow dissociation kinetics, cellular pharmacodynamic (PD) effects, and COLO205 growth inhibition. Additionally, molecular basis of high kinase selectivity of 10c is discussed by using the protein structures of Cdc7 and Cdk2. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecular differentiation of five Cinnamomum camphora chemotypes using desorption atmospheric pressure chemical ionization mass spectrometry of raw leaves

PubMed Central

Guo, Xiali; Cui, Meng; Deng, Min; Liu, Xingxing; Huang, Xueyong; Zhang, Xinglei; Luo, Liping

2017-01-01

Five chemotypes, the isoborneol-type, camphora-type, cineole-type, linalool-type and borneol-type of Cinnamomum camphora (L.) Presl have been identified at the molecular level based on the multivariate analysis of mass spectral fingerprints recorded from a total of 750 raw leaf samples (i.e., 150 leaves equally collected for each chemotype) using desorption atmospheric pressure chemical ionization mass spectrometry (DAPCI-MS). Both volatile and semi-volatile metabolites of the fresh leaves of C. camphora were simultaneously detected by DAPCI-MS without any sample pretreatment, reducing the analysis time from half a day using conventional methods (e.g., GC-MS) down to 30 s. The pattern recognition results obtained using principal component analysis (PCA) was cross-checked by cluster analysis (CA), showing that the difference visualized by the DAPCI-MS spectral fingerprints was validated with 100% accuracy. The study demonstrates that DAPCI-MS meets the challenging requirements for accurate differentiation of all the five chemotypes of C. camphora leaves, motivating more advanced application of DAPCI-MS in plant science and forestry studies. PMID:28425482

Acaricidal activity of essential oils from Lippia alba genotypes and its major components carvone, limonene, and citral against Rhipicephalus microplus.

PubMed

Peixoto, Magna Galvão; Costa-Júnior, Livio Martins; Blank, Arie Fitzgerald; Lima, Aldilene da Silva; Menezes, Thays Saynara Alves; Santos, Darlisson de Alexandria; Alves, Péricles Barreto; Cavalcanti, Sócrates Cabral de Holanda; Bacci, Leandro; Arrigoni-Blank, Maria de Fátima

2015-05-30

The goal of the present study was to evaluate the acaricidal potential of Lippia alba essential oil, citral chemotypes (LA-10 and LA-44 genotypes) and carvone chemotypes (LA-13 and LA-57 genotypes), as well as purified citral and enantiomers of carvone and limonene. Efficacy against Rhipicephalus microplus was assessed by the larval packet and the engorged female immersion tests. Citral chemotypes had greater larvicidal activity than carvone chemotypes, and this was further supported by larvicidal and adulticidal activity of purified citral with LC50 values of 7.0 and 29.8 mg/mL, respectively. While purified enantiomers of carvone exhibited greater larvicidal activity than those of limonene, enantioselectivity of limonene was observed with R-(+) displaying significantly higher efficacy (LC50 of 31.2mg/mL) than S-(-) (LC50 of 54.5mg/mL). The essential oils and purified compounds were much less toxic toward engorged adult females, with the exception of citral, and this may be due to limited cuticular penetration. Published by Elsevier B.V.

Phenotypic Variations in the Foliar Chemical Profile of Persea americana Mill. cv. Hass.

PubMed

García-Rodríguez, Yolanda Magdalena; Torres-Gurrola, Guadalupe; Meléndez-González, Claudio; Espinosa-García, Francisco J

2016-12-01

The Hass avocado tree Persea americana cv. Hass was derived from a single hybrid tree of P. americana var. drymifolia and P. americana var. guatemalensis, and it is propagated clonally by grafting. This cultivar is the most widely planted in the world but its profile of secondary metabolites has been studied rarely despite of its importance in plant protection. We illustrate the variability of the volatilome of mature leaves by describing the average chemical composition and the phenotypic variability found in 70 trees. Contrary to the uniformity expected in the Hass cultivar, high variability coefficients were found for most of the 36 detected foliar volatile compounds; furthermore we found six chemotypes grouping the foliar phenotypes of the sampled trees using hierarchical cluster analysis. About 48% of trees were grouped in one chemotype; five chemotypes grouped the remaining trees. The compounds that determined these chemotypes were: estragole, α-farnesene, β-caryophyllene, germacrene D, α-cubebene and eugenol. This striking variation in a cultivar propagated clonally is discussed in terms of somatic mutation. © 2016 Wiley-VHCA AG, Zurich, Switzerland.

Geographic distribution of three alkaloid chemotypes of Croton lechleri.

PubMed

Milanowski, Dennis J; Winter, Rudolph E K; Elvin-Lewis, Memory P F; Lewis, Walter H

2002-06-01

Three known alkaloids, isoboldine (2), norisoboldine (1), and magnoflorine (8), have been isolated for the first time from Croton lechleri, a source of the wound healing latex "sangre de grado". An HPLC system was developed, and a large number of latex and leaf samples of C. lechleri from 22 sites in northern Peru and Ecuador were analyzed to gain an understanding of the natural variation in alkaloid content for the species. Up to six alkaloids were found to occur in the leaves including, in addition to those listed above, thaliporphine (3), glaucine (4), and taspine (9), whereas the latex contained only 9. Taspine (9) is the component that has been previously found to be responsible for the wound healing activity of C. lechleri latex, and its mean concentration throughout the range examined was found to be 9% of the latex by dry weight. In addition, three chemotypes are defined based on the alkaloid content of the leaves, and the geographic distribution of these chemotypes is discussed along with a quantitative analysis of the alkaloid content as a function of chemotype.

Diel cycles of isoprenoids in the emissions of Norway spruce, different Scots pine chemotypes, and in Boreal forest ambient air during HUMPPA-COPEC-2010

NASA Astrophysics Data System (ADS)

Yassaa, N.; Williams, J.; Song, W.; Vanhatalo, A.; Bäck, J.; Lelieveld, J.

2012-04-01

Cuvette based emission rates of monoterpenes and sesquiterpenes from four chemotypes of Scots pine (Pinus sylvestris) and one chemotype of Norway spruce (Picea abies) as well as the ambient mixing ratios of monoterpenes were determined during HUMPPA-COPEC 2010 summer campaign. Differences in chemical composition as well as in emission strength were observed between the different chemotypes. The chemotypes of Scots pine can be classified according to species with high, no and intermediate content of Δ3-carene. The "no- Δ3-carene" chemotype was found to be the strongest emitter of monoterpenes. From this chemotype, β-myrcene, a very reactive organic gas, was the dominant species accounting for more than 35 % of the total emission rates of isoprenoids followed by ß-phellandrene (~34%). Myrcene emission rates ranged from 0.8 up to 24 µg/g (dw)/h. α-farnesene was the dominant sesquiterpene species, with measured average emission rates of 318 ng/g (dw)/h. In the high Δ3-carene chemotype, which is the most studied in Hyytiälä, Δ3-carene was more than 48 % of the total monoterpene emission. The mean Δ3-carene emission rate, circa 609 ng/g (dw)/h reported here is consistent with the previously reported value during the same season. The terpene emission from spruce was dominated by limonene (35%), ß-phellandrene (15%), α-pinene (14 %) and eucalyptol (9%). Total spruce monoterpene emissions ranged from 0.549 up to 12.2 µg/g (dw)/h. Overall the total terpene flux (monoterpenes + sesquiterpenes) from all studied plant species varied from 230 ng/g (dw)/h up to 66 µg/g (dw)/h. The total ambient monoterpenes (including α-pinene, Δ3-carene, ß-pinene and ß-myrcene) measured during the campaign varied in mixing ratio from a few ppt to over one ppb. The most abundant biogenic VOCs measured above the canopy were α-pinene and Δ3-carene and these two compounds together contributed more than 50% of the total monoterpenes. The diel cycles of isoprenoid mixing ratios showed high levels during the night-time which is consistent with continued low nocturnal emission and a low and stable boundary layer. The chirality of α-pinene was dominated by (+)-enantiomers both in the direct emission and in the atmosphere. The effect of herbivore attack on the plant shoot was studied and found to significantly influence the enantiomeric signature of monoterpenes in similar manner as has been observed from mechanical damage. The exceptionally hot temperatures recorded in the summer of 2010 were reflected by strong emission of terpenes and consequently high ambient mixing ratios.

Crystal structure of checkpoint kinase 2 in complex with NSC 109555, a potent and selective inhibitor

PubMed Central

Lountos, George T; Tropea, Joseph E; Zhang, Di; Jobson, Andrew G; Pommier, Yves; Shoemaker, Robert H; Waugh, David S

2009-01-01

Checkpoint kinase 2 (Chk2), a ser/thr kinase involved in the ATM-Chk2 checkpoint pathway, is activated by genomic instability and DNA damage and results in either arrest of the cell cycle to allow DNA repair to occur or apoptosis if the DNA damage is severe. Drugs that specifically target Chk2 could be beneficial when administered in combination with current DNA-damaging agents used in cancer therapy. Recently, a novel inhibitor of Chk2, NSC 109555, was identified that exhibited high potency (IC50 = 240 nM) and selectivity. This compound represents a new chemotype and lead for the development of novel Chk2 inhibitors that could be used as therapeutic agents for the treatment of cancer. To facilitate the discovery of new analogs of NSC 109555 with even greater potency and selectivity, we have solved the crystal structure of this inhibitor in complex with the catalytic domain of Chk2. The structure confirms that the compound is an ATP-competitive inhibitor, as the electron density clearly reveals that it occupies the ATP-binding pocket. However, the mode of inhibition differs from that of the previously studied structure of Chk2 in complex with debromohymenialdisine, a compound that inhibits both Chk1 and Chk2. A unique hydrophobic pocket in Chk2, located very close to the bound inhibitor, presents an opportunity for the rational design of compounds with higher binding affinity and greater selectivity. PMID:19177354

Prioritizing multiple therapeutic targets in parallel using automated DNA-encoded library screening

NASA Astrophysics Data System (ADS)

Machutta, Carl A.; Kollmann, Christopher S.; Lind, Kenneth E.; Bai, Xiaopeng; Chan, Pan F.; Huang, Jianzhong; Ballell, Lluis; Belyanskaya, Svetlana; Besra, Gurdyal S.; Barros-Aguirre, David; Bates, Robert H.; Centrella, Paolo A.; Chang, Sandy S.; Chai, Jing; Choudhry, Anthony E.; Coffin, Aaron; Davie, Christopher P.; Deng, Hongfeng; Deng, Jianghe; Ding, Yun; Dodson, Jason W.; Fosbenner, David T.; Gao, Enoch N.; Graham, Taylor L.; Graybill, Todd L.; Ingraham, Karen; Johnson, Walter P.; King, Bryan W.; Kwiatkowski, Christopher R.; Lelièvre, Joël; Li, Yue; Liu, Xiaorong; Lu, Quinn; Lehr, Ruth; Mendoza-Losana, Alfonso; Martin, John; McCloskey, Lynn; McCormick, Patti; O'Keefe, Heather P.; O'Keeffe, Thomas; Pao, Christina; Phelps, Christopher B.; Qi, Hongwei; Rafferty, Keith; Scavello, Genaro S.; Steiginga, Matt S.; Sundersingh, Flora S.; Sweitzer, Sharon M.; Szewczuk, Lawrence M.; Taylor, Amy; Toh, May Fern; Wang, Juan; Wang, Minghui; Wilkins, Devan J.; Xia, Bing; Yao, Gang; Zhang, Jean; Zhou, Jingye; Donahue, Christine P.; Messer, Jeffrey A.; Holmes, David; Arico-Muendel, Christopher C.; Pope, Andrew J.; Gross, Jeffrey W.; Evindar, Ghotas

2017-07-01

The identification and prioritization of chemically tractable therapeutic targets is a significant challenge in the discovery of new medicines. We have developed a novel method that rapidly screens multiple proteins in parallel using DNA-encoded library technology (ELT). Initial efforts were focused on the efficient discovery of antibacterial leads against 119 targets from Acinetobacter baumannii and Staphylococcus aureus. The success of this effort led to the hypothesis that the relative number of ELT binders alone could be used to assess the ligandability of large sets of proteins. This concept was further explored by screening 42 targets from Mycobacterium tuberculosis. Active chemical series for six targets from our initial effort as well as three chemotypes for DHFR from M. tuberculosis are reported. The findings demonstrate that parallel ELT selections can be used to assess ligandability and highlight opportunities for successful lead and tool discovery.

Comparison of the Fungicide Sensitivity of Alberta and Prince Edward Island Isolates of Fusarium graminearum Producing Either 3- or 15-acetyl Deoxynivalenol

USDA-ARS?s Scientific Manuscript database

Fusarium graminearum Schwabe of the ‘3ADON’ chemotype is now displacing ‘15ADON’ isolates in Canada. One concern regarding this shift in chemotypes is related to potential differences in fungicide sensitivity. This could have significant implications as fungicide application is an important strate...

Discovery of new antimalarial chemotypes through chemical methodology and library development.

PubMed

Brown, Lauren E; Chih-Chien Cheng, Ken; Wei, Wan-Guo; Yuan, Pingwei; Dai, Peng; Trilles, Richard; Ni, Feng; Yuan, Jing; MacArthur, Ryan; Guha, Rajarshi; Johnson, Ronald L; Su, Xin-zhuan; Dominguez, Melissa M; Snyder, John K; Beeler, Aaron B; Schaus, Scott E; Inglese, James; Porco, John A

2011-04-26

In an effort to expand the stereochemical and structural complexity of chemical libraries used in drug discovery, the Center for Chemical Methodology and Library Development at Boston University has established an infrastructure to translate methodologies accessing diverse chemotypes into arrayed libraries for biological evaluation. In a collaborative effort, the NIH Chemical Genomics Center determined IC(50)'s for Plasmodium falciparum viability for each of 2,070 members of the CMLD-BU compound collection using quantitative high-throughput screening across five parasite lines of distinct geographic origin. Three compound classes displaying either differential or comprehensive antimalarial activity across the lines were identified, and the nascent structure activity relationships (SAR) from this experiment used to initiate optimization of these chemotypes for further development.

A study of Salmonella typhi isolated in Suez Canal area. Biotyping, phage typing and colicinogenic property.

PubMed

Shoeb, S; Khalifa, I; el Daly, O; Heiba, A; Farmer, J; Brenner, F; el Batawi, Y

1989-01-01

In this work a total of 82 strains of Salmonella typhi were isolated from Egyptian patients diagnosed as quiry enteric fever. These cases were from Ismalia, Suez and port Said Areas. The strains fell in 16 phage types. Phage types N, 40, E1, and degraded Vi were the commonest phage type in Ismailia, while phage types degraded Vi and C1 were the commonest in Port Said. Phage types Di-N, degraded Vi, A and C1 were the commonest in Suez. Chemotyping of Salmonella typhi showed that the majority of the strains belonged to chemotype I (82%), and the rest belonged to chemotype II (18%). Colicin production was negative and all the strains were susceptible to the currently used antibiotics.

[Perilla resources of China and essential oil chemotypes of Perilla leaves].

PubMed

Wei, Chang-Ling; Guo, Bao-Lin; Zhang, Chen-Wu; Zhang, Fen; Tian, Jing; Bai, Xiao-Lin; Zhang, Shun-Nan

2016-05-01

This study, based on the findings for Perilla resources, aimed to describe the species, distribution, importance, features, utilization and status of quantitative Perilla resources in China. This not only helps people to know well about the existing resources and researching development, but also indicates the overall distribution, selection and rational use of Perilla resource in the future. According to the output types, Perilla resources are divided into two categories: wild resources and cultivated resources; and based on its common uses, the cultivated resources are further divided into medicine resources, seed-used resources and export resources. The distribution areas of wild resources include Henan, Sichuan, Anhui, Jiangxi, Guangxi, Hunan, Jiangsu and Zhejiang. The distribution areas of medicine resources are concentrated in Hebei, Anhui, Chongqing, Guangxi and Guangdong. Seed-used resources are mainly distributed in Gansu, Heilongjiang, Jilin, Chongqing and Yunnan. Export resource areas are mainly concentrated in coastal cities, such as Zhejiang, Jiangsu, Shandong and Zhejiang. For the further study, the essential oil of leaf samples from different areas were extracted by the steam distillation method and analyzed by GC-MS. The differences in essential oil chemotypes among different Perilla leaves were compared by analyzing their chemical constituents. The main 31 constituents of all samples included: perillaketone (0.93%-96.55%), perillaldehyde (0.10%-61.24%), perillene (52.15%), caryophyllene (3.22%-26.67%), and α-farnesene (2.10%-21.54%). These samples can be classified into following five chemotypes based on the synthesis pathways: PK-type, PA-type, PL-type, PP-type and EK-type. The chemotypes of wild resources included PK-type and PA-type, with PK-type as the majority. All of the five chemotypes are included in cultivated resources, with PA-type as the majority. Seed-used resources are all PK-type, and export resources are all PA-type. The P. frutescens var. frutescens include five chemotypes, with PK-type as the majority. The PK-type leaves of P. frutescens var. acuta are green, while the PA-type leaves are reddish purple. The P. fruteseens var. crispa was mainly PA type with reddish purple leaves. The differences of the main chemotypes provide a scientific basis for distinguishing between Zisu and Baisu in previous literatures. Based on the lung toxicity of PK and the traditional use of Perilla, the testing standard of essential oil and Perilla herb shall be built, and PA type is recommended to be used in traditional Chinese medicine. Copyright© by the Chinese Pharmaceutical Association.

Evaluation of spiropiperidine hydantoins as a novel class of antimalarial agents.

PubMed

Meyers, Marvin J; Anderson, Elizabeth J; McNitt, Sarah A; Krenning, Thomas M; Singh, Megh; Xu, Jing; Zeng, Wentian; Qin, Limei; Xu, Wanwan; Zhao, Siting; Qin, Li; Eickhoff, Christopher S; Oliva, Jonathan; Campbell, Mary A; Arnett, Stacy D; Prinsen, Michael J; Griggs, David W; Ruminski, Peter G; Goldberg, Daniel E; Ding, Ke; Liu, Xiaorong; Tu, Zhengchao; Tortorella, Micky D; Sverdrup, Francis M; Chen, Xiaoping

2015-08-15

Given the rise of parasite resistance to all currently used antimalarial drugs, the identification of novel chemotypes with unique mechanisms of action is of paramount importance. Since Plasmodium expresses a number of aspartic proteases necessary for its survival, we have mined antimalarial datasets for drug-like aspartic protease inhibitors. This effort led to the identification of spiropiperidine hydantoins, bearing similarity to known inhibitors of the human aspartic protease β-secretase (BACE), as new leads for antimalarial drug discovery. Spiropiperidine hydantoins have a dynamic structure-activity relationship profile with positions identified as being tolerant of a variety of substitution patterns as well as a key piperidine N-benzyl phenol pharmacophore. Lead compounds 4e (CWHM-123) and 12k (CWHM-505) are potent antimalarials with IC50 values against Plasmodium falciparum 3D7 of 0.310 μM and 0.099 μM, respectively, and the former features equivalent potency on the chloroquine-resistant Dd2 strain. Remarkably, these compounds do not inhibit human aspartic proteases BACE, cathepsins D and E, or Plasmodium plasmepsins II and IV despite their similarity to known BACE inhibitors. Although the current leads suffer from poor metabolic stability, they do fit into a drug-like chemical property space and provide a new class of potent antimalarial agents for further study. Copyright © 2015 Elsevier Ltd. All rights reserved.

Intraspecific variation in essential oil composition of the medicinal plant Lippia integrifolia (Verbenaceae). Evidence for five chemotypes.

PubMed

Marcial, Guillermo; de Lampasona, Marina P; Vega, Marta I; Lizarraga, Emilio; Viturro, Carmen I; Slanis, Alberto; Juárez, Miguel A; Elechosa, Miguel A; Catalán, César A N

2016-02-01

The aerial parts of Lippia integrifolia (incayuyo) are widely used in northwestern and central Argentina for their medicinal and aromatic properties. The essential oil composition of thirty-one wild populations of L. integrifolia covering most of its natural range was analyzed by GC and GC-MS. A total of one hundred and fifty two terpenoids were identified in the essential oils. Sesquiterpenoids were the dominant components in all but one of the collections analyzed, the only exception being a sample collected in San Juan province where monoterpenoids amounted to 51%. Five clearly defined chemotypes were observed. One possessed an exquisite and delicate sweet aroma with trans-davanone as dominant component (usually above 80%). Another with an exotic floral odour was rich in oxygenated sesquiterpenoids based on the rare lippifoliane and africanane skeletons. The trans-davanone chemotype is the first report of an essential oil containing that sesquiterpene ketone as the main constituent. The absolute configuration of trans-davanone from L. integrifolia was established as 6S, 7S, 10S, the enantiomer of trans-davanone from 'davana oil' (Artemisia pallens). Wild plants belonging to trans-davanone and lippifolienone chemotypes were propagated and cultivated in the same parcel of land in Santa Maria, Catamarca. The essential oil compositions of the cultivated plants were essentially identical to the original plants in the wild, indicating that the essential oil composition is largely under genetic control. Specimens collected near the Bolivian border that initially were identified as L. boliviana Rusby yielded an essential oil practically identical to the trans-davanone chemotype of L. integrifolia supporting the recent view that L. integrifolia (Gris.) Hieron. and L. boliviana Rusby are synonymous. Copyright © 2015 Elsevier Ltd. All rights reserved.

Antitrypanosomal lead discovery: Identification of a ligand-efficient inhibitor of Trypanosoma cruzi CYP51 and parasite growth

PubMed Central

Andriani, Grasiella; Amata, Emanuele; Beatty, Joel; Clements, Zeke; Coffey, Brian J.; Courtemanche, Gilles; Devine, William; Erath, Jessey; Juda, Cristin E.; Wawrzak, Zdzislaw; Wood, JodiAnne T.; Lepesheva, Galina I.; Rodriguez, Ana; Pollastri, Michael P.

2013-01-01

Chagas disease is caused by the intracellular protozoan parasite Trypanosomal cruzi, and current drugs are lacking in terms of desired safety and efficacy profiles. Following on a recently reported high-throughput screening campaign, we have explored initial structure-activity relationships around a class of imidazole-based compounds. This profiling has uncovered compounds 4c (NEU321) and 4j (NEU704), which are potent against in vitro cultures of T. cruzi and are greater than 160-fold selective over host cells. We report in vitro drug metabolism and properties profiling of 4c and show that this chemotype inhibits the T cruzi CYP51 enzyme, an observation confirmed by X-ray crystallographic analysis. We compare the binding orientation of 4c to that of other, previously reported inhibitors. We show that 4c displays a significantly better ligand efficiency and a shorter synthetic route over previously disclosed CYP51 inhibitors, and should therefore be considered a promising lead compound for further optimization. PMID:23448316

Discovery of potent 1H-imidazo[4,5-b]pyridine-based c-Met kinase inhibitors via mechanism-directed structural optimization.

PubMed

An, Xiao-De; Liu, Hongyan; Xu, Zhong-Liang; Jin, Yi; Peng, Xia; Yao, Ying-Ming; Geng, Meiyu; Long, Ya-Qiu

2015-02-01

Starting from our previously identified novel c-Met kinase inhibitors bearing 1H-imidazo[4,5-h][1,6]naphthyridin-2(3H)-one scaffold, a global structural exploration was conducted to furnish an optimal binding motif for further development, directed by the enzyme inhibitory mechanism. First round SAR study picked two imidazonaphthyridinone frameworks with 1,8- and 3,5-disubstitution pattern as class I and class II c-Met kinase inhibitors, respectively. Further structural optimization on type II inhibitors by truncation of the imidazonaphthyridinone core and incorporation of an N-phenyl cyclopropane-1,1-dicarboxamide pharmacophore led to the discovery of novel imidazopyridine-based c-Met kinase inhibitors, displaying nanomolar enzyme inhibitory activity and improved Met kinase selectivity. More significantly, the new chemotype c-Met kinase inhibitors effectively inhibited Met phosphorylation and its downstream signaling as well as the proliferation of Met-dependent EBC-1 human lung cancer cells at submicromolar concentrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Molecular structures of cdc2-like kinases in complex with a new inhibitor chemotype

PubMed Central

Helmer, Renate; Loaëc, Nadège; Preu, Lutz; Ott, Ingo; Knapp, Stefan; Meijer, Laurent

2018-01-01

Cdc2-like kinases (CLKs) represent a family of serine-threonine kinases involved in the regulation of splicing by phosphorylation of SR-proteins and other splicing factors. Although compounds acting against CLKs have been described, only a few show selectivity against dual-specificity tyrosine phosphorylation regulated-kinases (DYRKs). We here report a novel CLK inhibitor family based on a 6,7-dihydropyrrolo[3,4-g]indol-8(1H)-one core scaffold. Within the series, 3-(3-chlorophenyl)-6,7-dihydropyrrolo[3,4-g]indol-8(1H)-one (KuWal151) was identified as inhibitor of CLK1, CLK2 and CLK4 with a high selectivity margin towards DYRK kinases. The compound displayed a potent antiproliferative activity in an array of cultured cancer cell lines. The X-ray structure analyses of three members of the new compound class co-crystallized with CLK proteins corroborated a molecular binding mode predicted by docking studies. PMID:29723265

Chemical composition of the essential oil from basil (Ocimum basilicum Linn.) and its in vitro cytotoxicity against HeLa and HEp-2 human cancer cell lines and NIH 3T3 mouse embryonic fibroblasts.

PubMed

Kathirvel, Poonkodi; Ravi, Subban

2012-01-01

This study examines the chemical composition and in vitro anticancer activity of the essential oil from Ocimum basilicum Linn. (Lamiaceae), cultivated in the Western Ghats of South India. The chemical compositions of basil fresh leaves were identified by GC-MS: 11 components were identified. The major constituents were found to be methyl cinnamate (70.1%), linalool (17.5%), β-elemene (2.6%) and camphor (1.52%). The results revealed that this plant may belong to the methyl cinnamate and linalool chemotype. A methyl thiazol tetrazolium assay was used for in vitro cytotoxicity screening against the human cervical cancer cell line (HeLa), human laryngeal epithelial carcinoma cell line (HEp-2) and NIH 3T3 mouse embryonic fibroblasts. The IC(50) values obtained were 90.5 and 96.3 µg mL(-1), respectively, and the results revealed that basil oil has potent cytotoxicity.

Essential Oils of Hyptis pectinata Chemotypes: Isolation, Binary Mixtures and Acute Toxicity on Leaf-Cutting Ants.

PubMed

Feitosa-Alcantara, Rosana B; Bacci, Leandro; Blank, Arie F; Alves, Péricles B; Silva, Indira Morgana de A; Soares, Caroline A; Sampaio, Taís S; Nogueira, Paulo Cesar de L; Arrigoni-Blank, Maria de Fátima

2017-04-12

Leaf-cutting ants are pests of great economic importance due to the damage they cause to agricultural and forest crops. The use of organosynthetic insecticides is the main form of control of these insects. In order to develop safer technology, the objective of this work was to evaluate the formicidal activity of the essential oils of two Hyptis pectinata genotypes (chemotypes) and their major compounds on the leaf-cutting ants Acromyrmex balzani Emery and Atta sexdens rubropilosa Forel. Bioassays of exposure pathways (contact and fumigation) and binary mixtures of the major compounds were performed. The major compounds identified in the essential oils of H. pectinata were β-caryophyllene, caryophyllene oxide and calamusenone. The essential oils of H. pectinata were toxic to the ants in both exposure pathways. Essential oils were more toxic than their major compounds alone. The chemotype calamusenone was more toxic to A. balzani in both exposure pathways. A. sexdens rubropilosa was more susceptible to the essential oil of the chemotype β-caryophyllene in both exposure pathways. In general, the binary mixtures of the major compounds resulted in additive effect of toxicity. The essential oils of H. pectinata is a raw material of great potential for the development of new insecticides.

Characterization of Stachybotrys from water-damaged buildings based on morphology, growth, and metabolite production.

PubMed

Andersen, Birgitte; Nielsen, Kristian F; Jarvis, Bruce B

2002-01-01

Stachybotrys was found to be associated with idiopathic pulmonary hemorrhage in infants in Cleveland, Ohio. Since that time, considerable effort has been put into finding the toxic components responsible for the disease. The name Stachybotrys chartarum has been applied to most of these isolates, but inconsistent toxicity results and taxonomic confusion prompted the present study. In this study, 122 Stachybotrys isolates, mainly from water-damaged buildings, were characterized and identified by combining three different approaches: morphology, colony characteristics, and metabolite production. Two different Stachybotrys taxa, S. chartarum and one undescribed species, were found in water-damaged buildings regardless of whether the buildings were in Denmark, Finland, or the USA. Furthermore, two chemotypes could be distinguished in S. chartarum. One chemotype produced atranones, whereas the other was a macrocyclic trichothecene-producer. The second undescribed taxon produced atranones and could be differentiated from S. chartarum by its growth characteristics and pigment production. Our results correlate with different inflammatory and toxicological properties reported for these same isolates and show that the three taxa/chemotypes should be treated separately. The co-occurrence of these three taxa/chemotypes in water-damaged buildings explains the inconsistent results in the literature concerning toxicity of Stachybotrys isolated from that environment.

Discovery and characterization of inhibitors of human palmitoyl acyltransferases.

PubMed

Ducker, Charles E; Griffel, Lindsay K; Smith, Ryan A; Keller, Staci N; Zhuang, Yan; Xia, Zuping; Diller, John D; Smith, Charles D

2006-07-01

The covalent attachment of palmitate to specific proteins by the action of palmitoyl acyltransferases (PAT) plays critical roles in the biological activities of several oncoproteins. Two PAT activities are expressed by human cells: type 1 PATs that modify the farnesyl-dependent palmitoylation motif found in H- and N-Ras, and type 2 PATs that modify the myristoyl-dependent palmitoylation motif found in the Src family of tyrosine kinases. We have previously shown that the type 1 PAT HIP14 causes cellular transformation. In the current study, we show that mRNA encoding HIP14 is up-regulated in a number of types of human tumors. To assess the potential of HIP14 and other PATs as targets for new anticancer drugs, we developed three cell-based assays suitable for high-throughput screening to identify inhibitors of these enzymes. Using these screens, five chemotypes, with activity toward either type 1 or type 2 PAT activity, were identified. The activity of the hits were confirmed using assays that quantify the in vitro inhibition of PAT activity, as well as a cell-based assay that determines the abilities of the compounds to prevent the localization of palmitoylated green fluorescent proteins to the plasma membrane. Representative compounds from each chemotype showed broad antiproliferative activity toward a panel of human tumor cell lines and inhibited the growth of tumors in vivo. Together, these data show that PATs, and HIP14 in particular, are interesting new targets for anticancer compounds, and that small molecules with such activity can be identified by high-throughput screening.

Discovery and characterization of inhibitors of human palmitoyl acyltransferases

PubMed Central

Ducker, Charles E.; Griffel, Lindsay K.; Smith, Ryan A.; Keller, Staci N.; Zhuang, Yan; Xia, Zuping; Diller, John D.; Smith, Charles D.

2010-01-01

The covalent attachment of palmitate to specific proteins by the action of palmitoyl acyltransferases (PAT) plays critical roles in the biological activities of several oncoproteins. Two PAT activities are expressed by human cells: type 1 PATs that modify the farnesyl-dependent palmitoylation motif found in H- and N-Ras, and type 2 PATs that modify the myristoyl-dependent palmitoylation motif found in the Src family of tyrosine kinases. We have previously shown that the type 1 PAT HIP14 causes cellular transformation. In the current study, we show that mRNA encoding HIP14 is up-regulated in a number of types of human tumors. To assess the potential of HIP14 and other PATs as targets for new anticancer drugs, we developed three cell-based assays suitable for high-throughput screening to identify inhibitors of these enzymes. Using these screens, five chemotypes, with activity toward either type 1 or type 2 PAT activity, were identified. The activity of the hits were confirmed using assays that quantify the in vitro inhibition of PAT activity, as well as a cell-based assay that determines the abilities of the compounds to prevent the localization of palmitoylated green fluorescent proteins to the plasma membrane. Representative compounds from each chemotype showed broad antiproliferative activity toward a panel of human tumor cell lines and inhibited the growth of tumors in vivo. Together, these data show that PATs, and HIP14 in particular, are interesting new targets for anticancer compounds, and that small molecules with such activity can be identified by high-throughput screening. PMID:16891450

Pharmacological Targeting Of Neuronal Kv7.2/3 Channels: A Focus On Chemotypes And Receptor Sites.

PubMed

Miceli, Francesco; Soldovieri, Maria Virginia; Ambrosino, Paolo; Manocchio, Laura; Medoro, Alessandro; Mosca, Ilaria; Taglialatela, Maurizio

2017-10-12

The Kv7 (KCNQ) subfamily of voltage-gated potassium channels consists of 5 members (Kv7.1-5) each showing a characteristic tissue distribution and physiological roles. Given their functional heterogeneity, Kv7 channels represent important pharmacological targets for development of new drugs for neuronal, cardiac and metabolic diseases. In the present manuscript, we focus on describing the pharmacological relevance and the potential therapeutic applications of drugs acting on neuronally-expressed Kv7.2/3 channels, placing particular emphasis on the different modulator chemotypes, and highlighting their pharmacodynamic and, whenever possible, pharmacokinetic peculiarities. The present work is based on an in-depth search of the currently available scientific literature, and on our own experience and knowledge in the field of neuronal Kv7 channel pharmacology. Space limitations impeded to describe the full pharmacological potential of Kv7 channels; thus, we have chosen to focus on neuronal channels composed of Kv7.2 and Kv7.3 subunits, and to mainly concentrate on their involvement in epilepsy. An astonishing heterogeneity in the molecular scaffolds exploitable to develop Kv7.2/3 modulators is evident, with important structural/functional peculiarities of distinct compound classes. In the present work we have attempted to show the current status and growing potential of the Kv7 pharmacology field. We anticipate a bright future for the field, and we express our hopes that the efforts herein reviewed will result in an improved treatment of hyperexcitability (or any other) diseases. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

A Target-Based High Throughput Screen Yields Trypanosoma brucei Hexokinase Small Molecule Inhibitors with Antiparasitic Activity

PubMed Central

Sharlow, Elizabeth R.; Lyda, Todd A.; Dodson, Heidi C.; Mustata, Gabriela; Morris, Meredith T.; Leimgruber, Stephanie S.; Lee, Kuo-Hsiung; Kashiwada, Yoshiki; Close, David; Lazo, John S.; Morris, James C.

2010-01-01

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 γ-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 ∼20-17,000-fold more potent than lonidamine, a previously identified TbHK1 inhibitor. Seven compounds inhibited T. brucei blood stage form parasite growth (0.03≤EC50<3 µM) with parasite specificity of the compounds being demonstrated using insect stage T. brucei parasites, Leishmania promastigotes, and mammalian cell lines. Analysis of two structurally related compounds, ebselen and SID 17387000, revealed that both were mixed inhibitors of TbHK1 with respect to ATP. Additionally, both compounds inhibited parasite lysate-derived HK activity. 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. PMID:20405000

Development and Mechanism of γ-Secretase Modulators for Alzheimer Disease

PubMed Central

Crump, Christina J.; Johnson, Douglas S.; Li, Yue-Ming

2013-01-01

γ-Secretase is an aspartyl intramembranal protease composed of presenilin, Nicastrin, Aph1 and Pen2 with 19 transmembrane domains. γ-Secretase cleaves the amyloid precursor proteins (APP) to release Aβ peptides that likely play a causative role in the pathogenesis of Alzheimer disease (AD). In addition, γ-secretase cleaves Notch and other type I membrane proteins. γ-Secretase inhibitors (GSIs) have been developed and used for clinical studies. However, clinical trials have shown adverse effects of GSIs that are potentially linked with non-discriminatory inhibition of Notch signaling, overall APP processing and other substrate cleavages. Therefore, these findings call for the development of disease modifying agents that target γ-secretase activity to lower Aβ42 production without blocking the overall processing of γ-secretase substrates. γ-Secretase modulators (GSMs) originally derived from non-steroidal anti-inflammatory drugs (NSAIDs) display such characteristics and are the focus of this review. However, first generation GSMs have limited potential due to low potency and undesired neuropharmacokinetic properties. This generation of GSMs has been suggested to interact with the APP substrate, γ-secretase or both. To improve the potency and brain availability, second generation GSMs including NSAID-derived carboxylic acid and non-NSAID-derived heterocyclic chemotypes as well as natural product-derived GSMs have been developed. Animal studies of this generation of GSMs have shown encouraging preclinical profiles. Moreover, using potent GSM photoaffinity probes, multiple studies unambiguously have showed that both carboxylic acid and heterocyclic GSMs specifically target presenilin, the catalytic subunit of γ-secretase. In addition, two types of GSMs have distinct binding sites within the γ-secretase complex and exhibit different Aβ profiles. GSMs induce a conformational change of γ-secretase to achieve modulation. Various models are proposed and discussed. Despite the progress of GSM research, many outstanding issues remain to be investigated to achieve the ultimate goal of developing GSMs as effective AD therapies. PMID:23614767

Structure-activity relationships amongst 4-position quinoline methanol antimalarials that inhibit the growth of drug sensitive and resistant strains of Plasmodium falciparum.

PubMed

Milner, Erin; McCalmont, William; Bhonsle, Jayendra; Caridha, Diana; Carroll, Dustin; Gardner, Sean; Gerena, Lucia; Gettayacamin, Montip; Lanteri, Charlotte; Luong, Thulan; Melendez, Victor; Moon, Jay; Roncal, Norma; Sousa, Jason; Tungtaeng, Anchalee; Wipf, Peter; Dow, Geoffrey

2010-02-15

Utilizing mefloquine as a scaffold, a next generation quinoline methanol (NGQM) library was constructed to identify early lead compounds that possess biological properties consistent with the target product profile for malaria chemoprophylaxis while reducing permeability across the blood-brain barrier. The library of 200 analogs resulted in compounds that inhibit the growth of drug sensitive and resistant strains of Plasmodium falciparum. Herein we report selected chemotypes and the emerging structure-activity relationship for this library of quinoline methanols. Published by Elsevier Ltd.

Genetic Divergence and Chemotype Diversity in the Fusarium Head Blight Pathogen Fusarium poae.

PubMed

Vanheule, Adriaan; De Boevre, Marthe; Moretti, Antonio; Scauflaire, Jonathan; Munaut, Françoise; De Saeger, Sarah; Bekaert, Boris; Haesaert, Geert; Waalwijk, Cees; van der Lee, Theo; Audenaert, Kris

2017-08-23

Fusarium head blight is a disease caused by a complex of Fusarium species. F. poae is omnipresent throughout Europe in spite of its low virulence. In this study, we assessed a geographically diverse collection of F. poae isolates for its genetic diversity using AFLP (Amplified Fragment Length Polymorphism). Furthermore, studying the mating type locus and chromosomal insertions, we identified hallmarks of both sexual recombination and clonal spread of successful genotypes in the population. Despite the large genetic variation found, all F. poae isolates possess the nivalenol chemotype based on Tri7 sequence analysis. Nevertheless, Tri gene clusters showed two layers of genetic variability. Firstly, the Tri1 locus was highly variable with mostly synonymous mutations and mutations in introns pointing to a strong purifying selection pressure. Secondly, in a subset of isolates, the main trichothecene gene cluster was invaded by a transposable element between Tri5 and Tri6 . To investigate the impact of these variations on the phenotypic chemotype, mycotoxin production was assessed on artificial medium. Complex blends of type A and type B trichothecenes were produced but neither genetic variability in the Tri genes nor variability in the genome or geography accounted for the divergence in trichothecene production. In view of its complex chemotype, it will be of utmost interest to uncover the role of trichothecenes in virulence, spread and survival of F. poae .

Characterizing the Diversity and Biological Relevance of the MLPCN Assay Manifold and Screening Set

PubMed Central

Zhang, Jintao; Lushington, Gerald H.; Huan, Jun

2011-01-01

The NIH Molecular Libraries Initiative (MLI), launched in 2004 with initial goals of identifying chemical probes for characterizing gene function and druggability, has produced PubChem, a chemical genomics knowledgebase for fostering translation of basic research into new therapeutic strategies. This paper assesses progress toward these goals by evaluating MLI target novelty and propensity for undergoing biochemically or therapeutically relevant modulations and the degree of chemical diversity and biogenic bias inherent in the MLI screening set. Our analyses suggest that while MLI target selection has not yet been fully optimized for biochemical diversity, it covers biologically interesting pathway space that complements established drug targets. We find the MLI screening set to be chemically diverse and to have greater biogenic bias than comparable collections of commercially available compounds. Biogenic enhancements such as incorporation of more metabolite-like chemotypes are suggested. PMID:21568288

Antispasmodic effects and composition of the essential oils from two South American chemotypes of Lippia alba.

PubMed

Blanco, Marcos A; Colareda, Germán A; van Baren, Catalina; Bandoni, Arnaldo L; Ringuelet, Jorge; Consolini, Alicia E

2013-10-07

Lippia alba (Mill.) N. E. Brown (Verbenaceae) is an aromatic species used in Central and South America as eupeptic for indigestion. In Argentina, it is used by the "criollos" from the Chaco province. There are several chemotypes which differ in the chemical composition of the essential oils. Nowadays, it is experimentally cultivated in some countries of the region, including Argentina. To compare the chemical composition and pharmacology of the essential oils from two chemotypes: "citral" (CEO) and "linalool" (LEO), in isolated rat duodenum and ileum. Contractile concentration-response curves (CRC) of acetylcholine (ACh) and calcium in 40mM K(+)-medium (Ca(2+)-CRC) were done in isolated intestine portions, in the absence and presence of CEO or LEO at different concentrations. Likewise verapamil, CEO and LEO induced a non-competitive inhibition of the ACh-CRC, with IC50 of 7.0±0.3mg CEO/mL and 37.2±4.2mg LEO/mL. l-NAME, a NO-synthase blocker, increased the IC50 of CEO to 26.1±8.7mg CEO/mL. Likewise verapamil, CEO and LEO non-competitively inhibited the Ca(2+)-CRC, with IC50 of 6.3±1.7mg CEO/mL, 7.0±2.5mg LEO/mL and 0.24±0.04mg verapamil/mL (pIC50: 6.28). CEO was proved to possess limonene, neral, geranial and (-)-carvone as the major components, while LEO was rich in linalool. Results suggest that CEO has five times more potency than LEO to inhibit muscarinic contractions. The essential oils of both chemotypes interfered with the Ca(2+)-influx, but with an IC50 about 28 times higher than that of verapamil. Moreover, CEO partially stimulated the NO production. These results show the medicinal usefulness of both Lippia alba chemotypes, thus validating its traditional use, potency and mechanism of action. © 2013 Published by Elsevier Ireland Ltd.

Dihydrobenz[e][1,4]oxazepin-2(3H)-ones, a new anthelmintic chemotype immobilising whipworm and reducing infectivity in vivo

PubMed Central

Bataille, Carole J. R.; Forman, Ruth; Heyer-Chauhan, Narinder; Marinič, Bruno; Sowood, Daniel J. C.; Wynne, Graham M.; Else, Kathryn J.; Russell, Angela J.

2017-01-01

Trichuris trichiura is a human parasitic whipworm infecting around 500 million people globally, damaging the physical growth and educational performance of those infected. Current drug treatment options are limited and lack efficacy against the worm, preventing an eradication programme. It is therefore important to develop new treatments for trichuriasis. Using Trichuris muris, an established model for T. trichiura, we screened a library of 480 novel drug-like small molecules for compounds causing paralysis of the ex vivo adult parasite. We identified a class of dihydrobenz[e][1,4]oxazepin-2(3H)-one compounds with anthelmintic activity against T. muris. Further screening of structurally related compounds and resynthesis of the most potent molecules led to the identification of 20 active dihydrobenzoxazepinones, a class of molecule not previously implicated in nematode control. The most active immobilise adult T. muris with EC50 values around 25–50μM, comparable to the existing anthelmintic levamisole. The best compounds from this chemotype show low cytotoxicity against murine gut epithelial cells, demonstrating selectivity for the parasite. Developing a novel oral pharmaceutical treatment for a neglected disease and deploying it via mass drug administration is challenging. Interestingly, the dihydrobenzoxazepinone OX02983 reduces the ability of embryonated T. muris eggs to establish infection in the mouse host in vivo. Complementing the potential development of dihydrobenzoxazepinones as an oral anthelmintic, this supports an alternative strategy of developing a therapeutic that acts in the environment, perhaps via a spray, to interrupt the parasite lifecycle. Together these results show that the dihydrobenzoxazepinones are a new class of anthelmintic, active against both egg and adult stages of Trichuris parasites. They demonstrate encouraging selectivity for the parasite, and importantly show considerable scope for further optimisation to improve potency and pharmacokinetic properties with the aim of developing a clinical agent. PMID:28182663

Dihydrobenz[e][1,4]oxazepin-2(3H)-ones, a new anthelmintic chemotype immobilising whipworm and reducing infectivity in vivo.

PubMed

Partridge, Frederick A; Murphy, Emma A; Willis, Nicky J; Bataille, Carole J R; Forman, Ruth; Heyer-Chauhan, Narinder; Marinič, Bruno; Sowood, Daniel J C; Wynne, Graham M; Else, Kathryn J; Russell, Angela J; Sattelle, David B

2017-02-01

Trichuris trichiura is a human parasitic whipworm infecting around 500 million people globally, damaging the physical growth and educational performance of those infected. Current drug treatment options are limited and lack efficacy against the worm, preventing an eradication programme. It is therefore important to develop new treatments for trichuriasis. Using Trichuris muris, an established model for T. trichiura, we screened a library of 480 novel drug-like small molecules for compounds causing paralysis of the ex vivo adult parasite. We identified a class of dihydrobenz[e][1,4]oxazepin-2(3H)-one compounds with anthelmintic activity against T. muris. Further screening of structurally related compounds and resynthesis of the most potent molecules led to the identification of 20 active dihydrobenzoxazepinones, a class of molecule not previously implicated in nematode control. The most active immobilise adult T. muris with EC50 values around 25-50μM, comparable to the existing anthelmintic levamisole. The best compounds from this chemotype show low cytotoxicity against murine gut epithelial cells, demonstrating selectivity for the parasite. Developing a novel oral pharmaceutical treatment for a neglected disease and deploying it via mass drug administration is challenging. Interestingly, the dihydrobenzoxazepinone OX02983 reduces the ability of embryonated T. muris eggs to establish infection in the mouse host in vivo. Complementing the potential development of dihydrobenzoxazepinones as an oral anthelmintic, this supports an alternative strategy of developing a therapeutic that acts in the environment, perhaps via a spray, to interrupt the parasite lifecycle. Together these results show that the dihydrobenzoxazepinones are a new class of anthelmintic, active against both egg and adult stages of Trichuris parasites. They demonstrate encouraging selectivity for the parasite, and importantly show considerable scope for further optimisation to improve potency and pharmacokinetic properties with the aim of developing a clinical agent.

ANTICHOLINESTERASE INSECTICIDE RETROSPECTIVE

PubMed Central

Casida, John E.; Durkin, Kathleen A.

2012-01-01

The anticholinesterase (antiChE) organophosphorus (OP) and methylcarbamate (MC) insecticides have been used very effectively as contact and systemic plant protectants for seven decades. About 90 of these compounds are still in use – the largest number for any insecticide chemotype or mode of action. In both insects and mammals, AChE inhibition and acetylcholine accumulation leads to excitation and death. The cholinergic system of insects is located centrally (where it is protected from ionized OPs and MCs) but not at the neuromuscular junction. Structural differences between insect and mammalian AChE are also evident in their genomics, amino acid sequences and active site conformations. Species selectivity is determined in part by inhibitor and target site specificity. Pest population selection with OPs and MCs has resulted in a multitude of modified AChEs of altered inhibitor specificity some conferring insecticide resistance and others enhancing sensitivity. Much of the success of antiChE insecticides results from a suitable balance of bioactivation and detoxification by families of CYP450 oxidases, hydrolases, glutathione S-transferases and others. Known inhibitors for these enzymes block detoxification and enhance potency which is particularly important in resistant strains. The current market for OPs and MCs of 19% of worldwide insecticide sales is only half of that of 10 years ago for several reasons: there have been no major new compounds for 30 years; resistance has eroded their effectiveness; human toxicity problems are still encountered; the patents have expired reducing the incentive to update registration packages; alternative chemotypes or control methods have been developed. Despite this decline, they still play a major role in pest control and the increasing knowledge on their target sites and metabolism may make it possible to redesign the inhibitors for insensitive AChEs and to target new sites in the cholinergic system. The OPs and MCs are down but not out. PMID:22926007

Anticholinesterase insecticide retrospective.

PubMed

Casida, John E; Durkin, Kathleen A

2013-03-25

The anticholinesterase (antiChE) organophosphorus (OP) and methylcarbamate (MC) insecticides have been used very effectively as contact and systemic plant protectants for seven decades. About 90 of these compounds are still in use - the largest number for any insecticide chemotype or mode of action. In both insects and mammals, AChE inhibition and acetylcholine accumulation leads to excitation and death. The cholinergic system of insects is located centrally (where it is protected from ionized OPs and MCs) but not at the neuromuscular junction. Structural differences between insect and mammalian AChE are also evident in their genomics, amino acid sequences and active site conformations. Species selectivity is determined in part by inhibitor and target site specificity. Pest population selection with OPs and MCs has resulted in a multitude of modified AChEs of altered inhibitor specificity some conferring insecticide resistance and others enhancing sensitivity. Much of the success of antiChE insecticides results from a suitable balance of bioactivation and detoxification by families of CYP450 oxidases, hydrolases, glutathione S-transferases and others. Known inhibitors for these enzymes block detoxification and enhance potency which is particularly important in resistant strains. The current market for OPs and MCs of 19% of worldwide insecticide sales is only half of that of 10 years ago for several reasons: there have been no major new compounds for 30 years; resistance has eroded their effectiveness; human toxicity problems are still encountered; the patents have expired reducing the incentive to update registration packages; alternative chemotypes or control methods have been developed. Despite this decline, they still play a major role in pest control and the increasing knowledge on their target sites and metabolism may make it possible to redesign the inhibitors for insensitive AChEs and to target new sites in the cholinergic system. The OPs and MCs are down but not out. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Back to the Future: Lessons Learned in Modern Target-based and Whole-Cell Lead Optimization of Antimalarials

PubMed Central

Chatterjee, Arnab K; Yeung, Bryan KS

2012-01-01

Antimalarial drug discovery has historically benefited from the whole-cell (phenotypic) screening approach to identify lead molecules in the search for new drugs. However over the past two decades there has been a shift in the pharmaceutical industry to move away from whole-cell screening to target-based approaches. As part of a Wellcome Trust and Medicines for Malaria Venture (MMV) funded consortium to discover new blood-stage antimalarials, we used both approaches to identify new antimalarial chemotypes, two of which have progressed beyond the lead optimization phase and display excellent in vivo efficacy in mice. These two advanced series were identified through a cell-based optimization devoid of target information and in this review we summarize the advantages of this approach versus a target-based optimization. Although the each lead optimization required slightly different medicinal chemistry strategies, we observed some common issues across the different the scaffolds which could be applied to other cell based lead optimization programs. PMID:22242845

Chemotyping the distribution of vitamin D metabolites in human serum

NASA Astrophysics Data System (ADS)

Müller, Miriam J.; Stokes, Caroline S.; Lammert, Frank; Volmer, Dietrich A.

2016-02-01

Most studies examining the relationships between vitamin D and disease or health focus on the main 25-hydroxyvitamin D3 (25(OH)D3) metabolite, thus potentially overlooking contributions and dynamic effects of other vitamin D metabolites, the crucial roles of several of which have been previously demonstrated. The ideal assay would determine all relevant high and low-abundant vitamin D species simultaneously. We describe a sensitive quantitative assay for determining the chemotypes of vitamin D metabolites from serum after derivatisation and ultra-high performance liquid chromatography-electrospray ionisation-tandem mass spectrometry (UHPLC-ESI-MS/MS). We performed a validation according to the ‘FDA Guidance for Industry Bioanalytical Method Validation’. The proof-of-concept of the method was then demonstrated by following the metabolite concentrations in patients with chronic liver diseases (CLD) during the course of a vitamin D supplementation study. The new quantitative profiling assay provided highly sensitive, precise and accurate chemotypes of the vitamin D metabolic process rather than the usually determined 25(OH)D3 concentrations.

Habitat-related variation in composition of the essential oil of Seseli rigidum Waldst. & Kit. (Apiaceae).

PubMed

Marčetić, Mirjana; Kovačević, Nada; Lakušić, Dmitar; Lakušić, Branislava

2017-03-01

Plant specialised metabolites like essential oils are highly variable depending on genetic and various ecological factors. The aim of the present work was to characterise essential oils of the species Seseli rigidum Waldst. & Kit. (Apiaceae) in various organs on the individual and populational levels. Geographical variability and the impact of climate and soil type on essential oil composition were also investigated. Individually sampled essential oils of roots, aerial parts and fruits of plants from seven populations were analysed by GC-FID and GC-MS. The investigated populations showed high interpopulational and especially intrapopulational variability of essential oil composition. In regard to the variability of essential oils, different chemotypes were defined. The essential oils of S. rigidum roots represented a falcarinol chemotype, oils of aerial parts constituted an α-pinene or α-pinene/sabinene chemotype and fruit essential oils can be characterised as belonging to a complex sabinene/α-pinene/β-phellandrene/falcarinol/germacrene B chemotype. At the species level, analysis of variance (ANOVA), principal component analysis (PCA) and canonical discriminant analysis (CDA) showed that the plant part exerted the strongest influence on the composition of essential oils. Climate had a high impact on composition of the essential oils of roots, aerial parts and fruits, while influence of the substrate was less pronounced. The variations in main compounds of essential oils based on climate or substrate were complex and specific to the plant part. Copyright © 2016 Elsevier Ltd. All rights reserved.

Withania somnifera chemotypes NMITLI 101R, NMITLI 118R, NMITLI 128R and withaferin A protect Mastomys coucha from Brugia malayi infection.

PubMed

Kushwaha, S; Soni, V K; Singh, P K; Bano, N; Kumar, A; Sangwan, R S; Misra-Bhattacharya, S

2012-04-01

Withania somnifera is an ayurvedic Indian medicinal plant whose immunomodulatory activities have been widely used as a home remedy for several ailments. We recently observed immunostimulatory properties in the root extracts of chemotypes NMITLI-101, NMITLI-118, NMITLI-128 and pure withanolide, withaferin A. In the present study, we evaluated the potential immunoprophylactic efficacies of these extracts against an infective pathogen. Our results show that administration of aqueous ethanol extracts (10 mg/kg) and withaferin A (0·3 mg/kg), 7 days before and after challenge with human filarial parasite Brugia malayi, offers differential protection in Mastomys coucha with chemotype 101R offering best protection (53·57%) as compared to other chemotypes. Our findings also demonstrate that establishment of B. malayi larvae was adversely affected by pretreatment with withaferin A as evidenced by 63·6% reduction in adult worm establishment. Moreover, a large percentage of the established female worms (66·2%) also showed defective embryogenesis. While the filaria-specific immunological response induced by withaferin A and NMITLI-101 showed a mixed Th1/Th2 phenotype, 118R stimulated production of IFN-γ and 128R increased levels of IL-4. Taken together, our findings reveal potential immunoprophylactic properties of W. somnifera, and further studies are needed to ascertain the benefits of this plant against other pathogens as well. © 2012 Blackwell Publishing Ltd.

Phytochemical Analysis and Antimicrobial, Antinociceptive, and Anti-Inflammatory Activities of Two Chemotypes of Pimenta pseudocaryophyllus (Myrtaceae)

PubMed Central

de Paula, Joelma Abadia Marciano; Silva, Maria do Rosário Rodrigues; Costa, Maysa P.; Diniz, Danielle Guimarães Almeida; Sá, Fabyola A. S.; Alves, Suzana Ferreira; Costa, Élson Alves; Lino, Roberta Campos; de Paula, José Realino

2012-01-01

Preparations from Pimenta pseudocaryophyllus (Gomes) L.R. Landrum (Myrtaceae) have been widely used in Brazilian folk medicine. This study aims to evaluate the antimicrobial activity of the crude ethanol extracts, fractions, semipurified substances, and essential oils obtained from leaves of two chemotypes of P. pseudocaryophyllus and to perform the antinociceptive and anti-inflammatory screening. The ethanol extracts were purified by column chromatography and main compounds were spectrally characterised (1D and 2D 1H and 13C NMR). The essential oils constituents were identified by GC/MS. The broth microdilution method was used for testing the antimicrobial activity. The abdominal contortions induced by acetic acid and the ear oedema induced by croton oil were used for screening of antinociceptive and anti-inflammatory activities, respectively. The phytochemical analysis resulted in the isolation of pentacyclic triterpenes, flavonoids, and phenol acids. The oleanolic acid showed the best profile of antibacterial activity for Gram-positive bacteria (31.2–125 μg mL−1), followed by the essential oil of the citral chemotype (62.5–250 μg mL−1). Among the semipurified substances, Ppm5, which contained gallic acid, was the most active for Candida spp. (31.2 μg mL−1) and Cryptococcus spp. (3.9–15.6 μg mL−1). The crude ethanol extract and fractions from citral chemotype showed antinociceptive and anti-inflammatory effects. PMID:23082081

Antioxidant and neurosedative properties of polyphenols and iridoids from Lippia alba.

PubMed

Hennebelle, Thierry; Sahpaz, Sevser; Gressier, Bernard; Joseph, Henry; Bailleul, François

2008-02-01

The neurosedative and antioxidative properties of some major compounds isolated from a citral chemotype of Lippia alba were investigated. Binding assays were performed on two CNS inhibitory targets: benzodiazepine and GABA(A) receptors. The most active compound was luteolin-7-diglucuronide, with half maximal inhibitory concentrations (IC(50)) of 101 and 40 microm, respectively. Fifteen compounds isolated from Lippia alba were tested for their radical scavenging capacities against DPPH. Four of the major compounds (verbascoside, calceolarioside E, luteolin-7-diglucuronide and theveside) were also tested for their antioxidant activity against superoxide radical-anion in cell-free (hypoxanthine-xanthine oxidase) and cellular (PMA-stimulated neutrophil granulocytes) systems.

Identification of the First Marine-Derived Opioid Receptor "Balanced" Agonist with a Signaling Profile That Resembles the Endorphins.

PubMed

Johnson, Tyler A; Milan-Lobo, Laura; Che, Tao; Ferwerda, Madeline; Lambu, Eptisam; McIntosh, Nicole L; Li, Fei; He, Li; Lorig-Roach, Nicholas; Crews, Phillip; Whistler, Jennifer L

2017-03-15

Opioid therapeutics are excellent analgesics, whose utility is compromised by dependence. Morphine (1) and its clinically relevant derivatives such as OxyContin (2), Vicodin (3), and Dilaudid (4) are "biased" agonists at the μ opioid receptor (OR), wherein they engage G protein signaling but poorly engage β-arrestin and the endocytic machinery. In contrast, endorphins, the endogenous peptide agonists for ORs, are potent analgesics, show reduced liability for tolerance and dependence, and engage both G protein and β-arrestin pathways as "balanced" agonists. We set out to determine if marine-derived alkaloids could serve as novel OR agonist chemotypes with a signaling profile distinct from morphine and more similar to the endorphins. Screening of 96 sponge-derived extracts followed by LC-MS-based purification to pinpoint the active compounds and subsequent evaluation of a mini library of related alkaloids identified two structural classes that modulate the ORs. These included the following: aaptamine (10), 9-demethyl aaptamine (11), demethyl (oxy)-aaptamine (12) with activity at the δ-OR (EC 50 : 5.1, 4.1, 2.3 μM, respectively) and fascaplysin (17), and 10-bromo fascaplysin (18) with activity at the μ-OR (EC 50 : 6.3, 4.2 μM respectively). An in vivo evaluation of 10 using δ-KO mice indicated its previously reported antidepressant-like effects are dependent on the δ-OR. Importantly, 17 functioned as a balanced agonist promoting both G protein signaling and β-arrestin recruitment along with receptor endocytosis similar to the endorphins. Collectively these results demonstrate the burgeoning potential for marine natural products to serve as novel lead compounds for therapeutic targets in neuroscience research.

Antiplasmodial dihetarylthioethers target the coenzyme A synthesis pathway in Plasmodium falciparum erythrocytic stages.

PubMed

Weidner, Thomas; Lucantoni, Leonardo; Nasereddin, Abed; Preu, Lutz; Jones, Peter G; Dzikowski, Ron; Avery, Vicky M; Kunick, Conrad

2017-05-15

Malaria is a widespread infectious disease that threatens a large proportion of the population in tropical and subtropical areas. Given the emerging resistance against the current standard anti-malaria chemotherapeutics, the development of alternative drugs is urgently needed. New anti-malarials representing chemotypes unrelated to currently used drugs have an increased potential for displaying novel mechanisms of action and thus exhibit low risk of cross-resistance against established drugs. Phenotypic screening of a small library (32 kinase-inhibitor analogs) against Plasmodium falciparum NF54-luc asexual erythrocytic stage parasites identified a diarylthioether structurally unrelated to registered drugs. Hit expansion led to a series in which the most potent congener displayed nanomolar antiparasitic activity (IC 50  = 39 nM, 3D7 strain). Structure-activity relationship analysis revealed a thieno[2,3-d]pyrimidine on one side of the thioether linkage as a prerequisite for antiplasmodial activity. Within the series, the oxazole derivative KuWei173 showed high potency (IC 50  = 75 nM; 3D7 strain), good solubility in aqueous solvents (1.33 mM), and >100-fold selectivity toward human cell lines. Rescue experiments identified inhibition of the plasmodial coenzyme A synthesis as a possible mode of action for this compound class. The class of antiplasmodial bishetarylthioethers reported here has been shown to interfere with plasmodial coenzyme A synthesis, a mechanism of action not yet exploited for registered anti-malarial drugs. The oxazole congener KuWei173 displays double-digit nanomolar antiplasmodial activity, selectivity against human cell lines, high drug likeness, and thus represents a promising chemical starting point for further drug development.

Cellular Inhibition of Checkpoint Kinase 2 (Chk2) and Potentiation of Camptothecins and Radiation by the Novel Chk2 Inhibitor PV1019 [7-Nitro-1H-indole-2-carboxylic acid {4-[1-(guanidinohydrazone)-ethyl]-phenyl}-amide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jobson, Andrew G.; Lountos, George T.; Lorenzi, Philip L.

2010-04-05

Chk2 is a checkpoint kinase involved in the ataxia telangiectasia mutated pathway, which is activated by genomic instability and DNA damage, leading to either cell death (apoptosis) or cell cycle arrest. Chk2 provides an unexplored therapeutic target against cancer cells. We recently reported 4,4'-diacetyldiphenylurea-bis(guanylhydrazone) (NSC 109555) as a novel chemotype Chk2 inhibitor. We have now synthesized a derivative of NSC 109555, PV1019 (NSC 744039) [7-nitro-1H-indole-2-carboxylic acid {l_brace}4-[1-(guanidinohydrazone)-ethyl]-phenyl{r_brace}-amide], which is a selective submicromolar inhibitor of Chk2 in vitro. The cocrystal structure of PV1019 bound in the ATP binding pocket of Chk2 confirmed enzymatic/biochemical observations that PV1019 acts as a competitive inhibitormore » of Chk2 with respect to ATP. PV1019 was found to inhibit Chk2 in cells. It inhibits Chk2 autophosphorylation (which represents the cellular kinase activation of Chk2), Cdc25C phosphorylation, and HDMX degradation in response to DNA damage. PV1019 also protects normal mouse thymocytes against ionizing radiation-induced apoptosis, and it shows synergistic antiproliferative activity with topotecan, camptothecin, and radiation in human tumor cell lines. We also show that PV1019 and Chk2 small interfering RNAs can exert antiproliferative activity themselves in the cancer cells with high Chk2 expression in the NCI-60 screen. These data indicate that PV1019 is a potent and selective inhibitor of Chk2 with chemotherapeutic and radiosensitization potential.« less

Assay format as a critical success factor for identification of novel inhibitor chemotypes of tissue-nonspecific alkaline phosphatase from high-throughput screening.

PubMed

Chung, Thomas D Y; Sergienko, Eduard; Millán, José Luis

2010-04-27

The tissue-nonspecific alkaline phosphatase (TNAP) isozyme is centrally involved in the control of normal skeletal mineralization and pathophysiological abnormalities that lead to disease states such as hypophosphatasia, osteoarthritis, ankylosis and vascular calcification. TNAP acts in concert with the nucleoside triphosphate pyrophosphohydrolase-1 (NPP1) and the Ankylosis protein to regulate the extracellular concentrations of inorganic pyrophosphate (PP(i)), a potent inhibitor of mineralization. In this review we describe the serial development of two miniaturized high-throughput screens (HTS) for TNAP inhibitors that differ in both signal generation and detection formats, but more critically in the concentrations of a terminal alcohol acceptor used. These assay improvements allowed the rescue of the initially unsuccessful screening campaign against a large small molecule chemical library, but moreover enabled the discovery of several unique classes of molecules with distinct mechanisms of action and selectivity against the related placental (PLAP) and intestinal (IAP) alkaline phosphatase isozymes. This illustrates the underappreciated impact of the underlying fundamental assay configuration on screening success, beyond mere signal generation and detection formats.

Arzanol, an anti-inflammatory and anti-HIV-1 phloroglucinol alpha-Pyrone from Helichrysum italicum ssp. microphyllum.

PubMed

Appendino, Giovanni; Ottino, Michela; Marquez, Nieves; Bianchi, Federica; Giana, Anna; Ballero, Mauro; Sterner, Olov; Fiebich, Bernd L; Munoz, Eduardo

2007-04-01

An acetone extract of Helichrysum italicum ssp. microphyllum afforded the phloroglucinol alpha-pyrone arzanol (1a) as a potent NF-kappaB inhibitor. Arzanol is identical with homoarenol (2a), whose structure should be revised. The phloroglucinol-type structure of arzanol and the 1,2,4-trihydroxyphenyl-type structure of the base-induced fragmentation product of homoarenol could be reconciled in light of a retro-Fries-type fragmentation that triggers a change of the hydroxylation pattern of the aromatic moiety. On the basis of these findings, the structure of arenol, the major constituent of the clinically useful antibiotic arenarin, should be revised from 2b to 1b, solving a long-standing puzzle over its biogenetic derivation. An alpha-pyrone (micropyrone, 7), the monoterpene rac-E-omega-oleoyloxylinalol (10), four known tremetones (9a-d), and the dimeric pyrone helipyrone (8) were also obtained. Arzanol inhibited HIV-1 replication in T cells and the release of pro-inflammatory cytokines in LPS-stimulated primary monocytes, qualifying as a novel plant-derived anti-inflammatory and antiviral chemotype worth further investigation.

Computational fishing of new DNA methyltransferase inhibitors from natural products.

PubMed

Maldonado-Rojas, Wilson; Olivero-Verbel, Jesus; Marrero-Ponce, Yovani

2015-07-01

DNA methyltransferase inhibitors (DNMTis) have become an alternative for cancer therapies. However, only two DNMTis have been approved as anticancer drugs, although with some restrictions. Natural products (NPs) are a promising source of drugs. In order to find NPs with novel chemotypes as DNMTis, 47 compounds with known activity against these enzymes were used to build a LDA-based QSAR model for active/inactive molecules (93% accuracy) based on molecular descriptors. This classifier was employed to identify potential DNMTis on 800 NPs from NatProd Collection. 447 selected compounds were docked on two human DNA methyltransferase (DNMT) structures (PDB codes: 3SWR and 2QRV) using AutoDock Vina and Surflex-Dock, prioritizing according to their score values, contact patterns at 4 Å and molecular diversity. Six consensus NPs were identified as virtual hits against DNMTs, including 9,10-dihydro-12-hydroxygambogic, phloridzin, 2',4'-dihydroxychalcone 4'-glucoside, daunorubicin, pyrromycin and centaurein. This method is an innovative computational strategy for identifying DNMTis, useful in the identification of potent and selective anticancer drugs. Copyright © 2015 Elsevier Inc. All rights reserved.

Comprehensive Mechanistic Analysis of Hits from High-Throughput and Docking Screens against β-Lactamase

PubMed Central

Babaoglu, Kerim; Simeonov, Anton; Irwin, John J.; Nelson, Michael E.; Feng, Brian; Thomas, Craig J.; Cancian, Laura; Costi, M. Paola; Maltby, David A.; Jadhav, Ajit; Inglese, James; Austin, Christopher P.; Shoichet, Brian K.

2009-01-01

High-throughput screening (HTS) is widely used in drug discovery. Especially for screens of unbiased libraries, false positives can dominate “hit lists”; their origins are much debated. Here we determine the mechanism of every active hit from a screen of 70,563 unbiased molecules against β-lactamase using quantitative HTS (qHTS). Of the 1274 initial inhibitors, 95% were detergent-sensitive and were classified as aggregators. Among the 70 remaining were 25 potent, covalent-acting β-lactams. Mass spectra, counter-screens, and crystallography identified 12 as promiscuous covalent inhibitors. The remaining 33 were either aggregators or irreproducible. No specific reversible inhibitors were found. We turned to molecular docking to prioritize molecules from the same library for testing at higher concentrations. Of 16 tested, 2 were modest inhibitors. Subsequent X-ray structures corresponded to the docking prediction. Analog synthesis improved affinity to 8 µM. These results suggest that it may be the physical behavior of organic molecules, not their reactivity, that accounts for most screening artifacts. Structure-based methods may prioritize weak-but-novel chemotypes in unbiased library screens. PMID:18333608

HPLC-DAD-MS identification of bioactive secondary metabolites from Ferula communis roots.

PubMed

Arnoldi, Lolita; Ballero, Mauro; Fuzzati, Nicola; Maxia, Andrea; Mercalli, Enrico; Pagni, Luca

2004-06-01

A simple HPLC method was developed to distinguish between 'poisonous' and 'non-poisonous' chemotypes of Ferula communis. The method was performed on a C8 reverse phase analytical column using a binary eluent (aqueous TFA 0.01%-TFA 0.01% in acetonitrile) under gradient condition. The two chemotypes showed different fingerprints. The identification of five coumarins and eleven daucane derivatives by HPLC-diode array detection (HPLC-DAD) and HPLC-MS is described. A coumarin, not yet described, was detected. Copyright 2004 Elsevier B.V.

Effect of environmental factors on Fusarium population and associated trichothecenes in wheat grain grown in Jiangsu province, China.

PubMed

Dong, Fei; Qiu, Jianbo; Xu, Jianhong; Yu, Mingzheng; Wang, Shufang; Sun, Yue; Zhang, Gufeng; Shi, Jianrong

2016-08-02

The present study was performed to identify prevailing Fusarium species and the environmental factors affecting their frequencies and the contamination of grain with major mycotoxins in Jiangsu province. The precipitation levels were 184.2mm, 156.4mm, and 245.8mm in the years 2013-2015, respectively, and the temperature fluctuated by an average of 10.6±7.2°C in 2013, 10.9±7.2°C in 2014, and 10.6±6.3°C in 2015. Co-occurrence of deoxynivalenol (DON), 3-acetyldeoxynivalenol (3ADON), and 15-acetyldeoxynivalenol (15ADON) were observed in wheat. The average concentrations of DON were 879.3±1127.8, 627.8±640.5, and 1628.6±2,168.0μg/kg in 2013-2015, respectively. The average concentrations of 3ADON were 43.5±59.0, 71.2±102.5, and 33.5±111.9μg/kg in 2013-2015, respectively. We found that the average concentration of DON in wheat was positively correlated with precipitation (r=0.998, p<0.01), and 3ADON was negatively correlated with precipitation (r=-0.887, p<0.05). However, there was no correlation between precipitation and 15ADON or nivalenol (NIV). The differences in temperature were not as significant as the differences in rainfall amount over a short time period. Therefore, there were no correlations between temperature and the concentrations of trichothecenes, excluding 3ADON (r=0.996, p<0.01). Our data indicated that Fusarium asiaticum is the primary pathogenic fungus prevalent in the Fusarium head blight disease nursery. The trichothecene chemotype composition differed between Fusarium graminearum sensu stricto (s. str.) and F. asiaticum isolates. The 3ADON chemotype was found only among strains of F. asiaticum. The NIV chemotype was not observed among strains of F. graminearum, while the 15ADON chemotype represented 100% of the F. graminearum strains collected. The results of this study indicated no correlations between environmental conditions and the species or genetic chemotype composition of pathogens in Jiangsu province in 2013-2015. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous Quantification of Forskolin and Iso-Forskolin in Coleus forskohlii (Wild.) Briq. and Identification of Elite Chemotype, Collected from Eastern Ghats (India).

PubMed

Shukla, Pushpendra Kumar; Misra, Ankita; Kumar, Manish; Jaichand; Singh, Kuldeep; Akhtar, Juber; Srivastava, Sharad; Agrawal, Pawan K; Singh Rawat, Ajay K

2018-01-01

Coleus forskohlii is a well-known industrially important medicinal plant, for its high forskolin content. A simple, selective, and sensitive high-performance thin layer chromatography (HPTLC) method was developed and validated for simultaneous quantification of forskolin and iso-forskolin in C. forskohlii germplasm collected from the Eastern Ghats, India. Chromatographic separation of the targeted marker(s) was obtained on precoated silica plates using toluene: ethyl acetate: methanol (90:30:0.5, v/v/v) as the mobile phase. Densitometric quantification of forskolin and iso-forskolin was carried out at 545 nm. Forskolin and iso-forskolin were identified by comparing the ultraviolet spectra of standard and sample track at R f of 0.64 ± 0.02 and 0.36 ± 0.01, after derivatization with anisaldehyde sulfuric acid reagent. The linearity of both the analytes was obtained in the range of 300-1200 ng/spot with the regression coefficient ( R 2 ) of 0.991 and 0.986. Recovery of analyte (s) at three levels, namely, 100, 150, and 200 ng/spot was found to be 100.46% ± 0.29%, 99.64% ± 0.33%, 100.02% ± 0.76% and 99.76% ± 0.62%, 99.56% ± 0.35%, 100.02% ± 0.22%, respectively, for forskolin and iso-forskolin. The content of forskolin and iso-forskolin varies from 0.046% to 0.187% and 0.002% to 0.077%, respectively (dry weight basis), the maximum content of both the markers was found in NBC-31, from Thakurwada, Maharashtra. The developed HPTLC method was linear, accurate, and reliable as per the International Council for Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines. The study aids in the identification of elite chemotype for commercial prospection of industrially viable medicinal crop. 12 Samples are collected from different locations of the eastern ghat regionsQuantification of two major marker forskolin and iso forskolinThe maximum content of both the markers was found in NBC -31, from Thakurwada, MaharashtraIdentification of elite chemotype of collected samples may be useful for commercial prospection in industries.

¹H NMR and HPLC/DAD for Cannabis sativa L. chemotype distinction, extract profiling and specification.

PubMed

Peschel, Wieland; Politi, Matteo

2015-08-01

The medicinal use of different chemovars and extracts of Cannabis sativa L. requires standardization beyond ∆9-tetrahydrocannabinol (THC) with complementing methods. We investigated the suitability of (1)H NMR key signals for distinction of four chemotypes measured in deuterated dimethylsulfoxide together with two new validated HPLC/DAD methods used for identification and extract profiling based on the main pattern of cannabinoids and other phenolics alongside the assayed content of THC, cannabidiol (CBD), cannabigerol (CBG) their acidic counterparts (THCA, CBDA, CBGA), cannabinol (CBN) and cannflavin A and B. Effects on cell viability (MTT assay, HeLa) were tested. The dominant cannabinoid pairs allowed chemotype recognition via assignment of selective proton signals and via HPLC even in cannabinoid-low extracts from the THC, CBD and CBG type. Substantial concentrations of cannabinoid acids in non-heated extracts suggest their consideration for total values in chemotype distinction and specifications of herbal drugs and extracts. Cannflavin A/B are extracted and detected together with cannabinoids but always subordinated, while other phenolics can be accumulated via fractionation and detected in a wide fingerprint but may equally serve as qualitative marker only. Cell viability reduction in HeLa was more determined by the total cannabinoid content than by the specific cannabinoid profile. Therefore the analysis and labeling of total cannabinoids together with the content of THC and 2-4 lead cannabinoids are considered essential. The suitability of analytical methods and the range of compound groups summarized in group and ratio markers are discussed regarding plant classification and pharmaceutical specification. Copyright © 2015 Elsevier B.V. All rights reserved.

Identification of Terpenoid Chemotypes Among High (-)-trans-Δ9- Tetrahydrocannabinol-Producing Cannabis sativa L. Cultivars.

PubMed

Fischedick, Justin T

2017-01-01

Introduction: With laws changing around the world regarding the legal status of Cannabis sativa (cannabis) it is important to develop objective classification systems that help explain the chemical variation found among various cultivars. Currently cannabis cultivars are named using obscure and inconsistent nomenclature. Terpenoids, responsible for the aroma of cannabis, are a useful group of compounds for distinguishing cannabis cultivars with similar cannabinoid content. Methods: In this study we analyzed terpenoid content of cannabis samples obtained from a single medical cannabis dispensary in California over the course of a year. Terpenoids were quantified by gas chromatography with flame ionization detection and peak identification was confirmed with gas chromatography mass spectrometry. Quantitative data from 16 major terpenoids were analyzed using hierarchical clustering analysis (HCA), principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and orthogonal partial least squares discriminant analysis (OPLS-DA). Results: A total of 233 samples representing 30 cultivars were used to develop a classification scheme based on quantitative data, HCA, PCA, and OPLS-DA. Initially cultivars were divided into five major groups, which were subdivided into 13 classes based on differences in terpenoid profile. Different classification models were compared with PLS-DA and found to perform best when many representative samples of a particular class were included. Conclusion: A hierarchy of terpenoid chemotypes was observed in the data set. Some cultivars fit into distinct chemotypes, whereas others seemed to represent a continuum of chemotypes. This study has demonstrated an approach to classifying cannabis cultivars based on terpenoid profile.

Diterpenoid fingerprints in pine foliage across an environmental and chemotypic matrix: Isoabienol content is a key trait differentiating chemotypes.

PubMed

Kännaste, Astrid; Laanisto, Lauri; Pazouki, Leila; Copolovici, Lucian; Suhorutšenko, Marina; Azeem, Muhammad; Toom, Lauri; Borg-Karlson, Anna-Karin; Niinemets, Ülo

2018-03-01

Diterpenoids constitute an important part of oleoresin in conifer needles, but the environmental and genetic controls on diterpenoid composition are poorly known. We studied the presence of diterpenoids in four pine populations spanning an extensive range of nitrogen (N) availability. In most samples, isoabienol was the main diterpenoid. Additionally, low contents of (Z)-biformene, abietadiene isomers, manoyl oxide isomers, labda-7,13,14-triene and labda-7,14-dien-13-ol were quantified in pine needles. According to the occurrence and content of diterpenoids it was possible to distinguish 'non diterpenoid pines', 'high isoabienol pines', 'manoyl oxide - isoabienol pines' and 'other diterpenoid pines'. 'Non diterpenoid pines', 'high isoabienol pines' and 'other diterpenoid pines' were characteristic to the dry forest, yet the majority of pines (>80%) of the bog Laeva represented 'high isoabienol pines'. 'Manoyl oxide - isoabienol pines' were present only in the wet sites. Additionally, orthogonal partial least-squares analysis showed, that in the bogs foliar nitrogen content per dry mass (N M ) correlated to diterpenoids. Significant correlations existed between abietadienes, isoabienol and foliar N M in 'manoyl oxide - isoabienol pines', and chemotypic variation was also associated by population genetic distance estimated by nuclear microsatellite markers. Previously, the presence of low and high Δ-3-carene pines has been demonstrated, but the results of the current study indicate that also diterpenoids form an independent axis of chemotypic differentiation. Further studies are needed to understand whether the enhanced abundance of diterpenoids in wetter sites reflects a phenotypic or genotypic response. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evolution of the content of THC and other major cannabinoids in drug-type cannabis cuttings and seedlings during growth of plants.

PubMed

De Backer, Benjamin; Maebe, Kevin; Verstraete, Alain G; Charlier, Corinne

2012-07-01

In Europe, authorities frequently ask forensic laboratories to analyze seized cannabis plants to prove that cultivation was illegal (drug type and not fiber type). This is generally done with mature and flowering plants. However, authorities are often confronted with very young specimens. The aim of our study was to evaluate when the chemotype of cannabis plantlets can be surely determined through analysis of eight major cannabinoids content during growth. Drug-type seedlings and cuttings were cultivated, sampled each week, and analyzed by high-performance liquid chromatography with diode array detection. The chemotype of clones was recognizable at any developmental stage because of high total Δ(9)-tetrahydrocannabinol (THC) concentrations even at the start of the cultivation. Conversely, right after germination seedlings contained a low total THC content, but it increased quickly with plant age up, allowing chemotype determination after 3 weeks. In conclusion, it is not necessary to wait for plants' flowering to identify drug-type cannabis generally cultivated in Europe. © 2012 American Academy of Forensic Sciences.

SHOP: a method for structure-based fragment and scaffold hopping.

PubMed

Fontaine, Fabien; Cross, Simon; Plasencia, Guillem; Pastor, Manuel; Zamora, Ismael

2009-03-01

A new method for fragment and scaffold replacement is presented that generates new families of compounds with biological activity, using GRID molecular interaction fields (MIFs) and the crystal structure of the targets. In contrast to virtual screening strategies, this methodology aims only to replace a fragment of the original molecule, maintaining the other structural elements that are known or suspected to have a critical role in ligand binding. First, we report a validation of the method, recovering up to 95% of the original fragments searched among the top-five proposed solutions, using 164 fragment queries from 11 diverse targets. Second, six key customizable parameters are investigated, concluding that filtering the receptor MIF using the co-crystallized ligand atom type has the greatest impact on the ranking of the proposed solutions. Finally, 11 examples using more realistic scenarios have been performed; diverse chemotypes are returned, including some that are similar to compounds that are known to bind to similar targets.

Sideritis romana L. subsp. purpurea (Tal. ex Benth.) Heywood, a new chemotype from Montenegro.

PubMed

Garzoli, Stefania; Božović, Mijat; Baldisserotto, Anna; Andreotti, Elisa; Pepi, Federico; Tadić, Vanja; Manfredini, Stefano; Ragno, Rino

2018-05-01

A study on essential oil fractions of the Western Balkan endemic Sideritis romana L. subsp. purpurea (Tal. ex Benth.) Heywood collected in Montenegro is reported. The 24-h systematic steam distillation extraction procedure was performed. The gas chromatographic/mass spectrometric (GC/MS) analysis of the fractions showed γ-elemene and spathulenol as two main constituents, revealing a new chemotype of this plant species. Although varying in the content of these two main compounds, which makes the fractions quite different between each other, evaluation of the anti-Candida activity showed the lack of any significant efficacy.

Discovery and Biological Evaluation of a Series of Pyrrolo[2,3-b]pyrazines as Novel FGFR Inhibitors.

PubMed

Zhang, Yan; Liu, Hongchun; Zhang, Zhen; Wang, Ruifeng; Liu, Tongchao; Wang, Chaoyun; Ma, Yuchi; Ai, Jing; Zhao, Dongmei; Shen, Jingkang; Xiong, Bing

2017-04-05

Abnormality of fibroblast growth factor receptor (FGFR)-mediated signaling pathways were frequently found in various human malignancies, making FGFRs hot targets for cancer treatment. To address the consistent need for a new chemotype of FGFR inhibitors, here, we started with a hit structure identified from our internal hepatocyte growth factor receptor (also called c-Met) inhibitor project, and conducted a chemical optimization. After exploring three parts of the hit compound, we finally discovered a new series of pyrrolo[2,3- b ]pyrazine FGFR inhibitors, which contain a novel scaffold and unique molecular shape. We believe that our findings can help others to further develop selective FGFR inhibitors.

1,2,6-Thiadiazinones as Novel Narrow Spectrum Calcium/Calmodulin-Dependent Protein Kinase Kinase 2 (CaMKK2) Inhibitors.

PubMed

Asquith, Christopher R M; Godoi, Paulo H; Couñago, Rafael M; Laitinen, Tuomo; Scott, John W; Langendorf, Christopher G; Oakhill, Jonathan S; Drewry, David H; Zuercher, William J; Koutentis, Panayiotis A; Willson, Timothy M; Kalogirou, Andreas S

2018-05-19

We demonstrate for the first time that 4 H -1,2,6-thiadiazin-4-one (TDZ) can function as a chemotype for the design of ATP-competitive kinase inhibitors. Using insights from a co-crystal structure of a 3,5-bis(arylamino)-4 H -1,2,6-thiadiazin-4-one bound to calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2), several analogues were identified with micromolar activity through targeted displacement of bound water molecules in the active site. Since the TDZ analogues showed reduced promiscuity compared to their 2,4-dianilinopyrimidine counter parts, they represent starting points for development of highly selective kinase inhibitors.

Variability in chemical constituents in Petasites hybridus from Austria.

PubMed

Chizzola; Ozelsberger; Langer

2000-06-01

Petasites hybridus (Asteraceae), butter bur, is an ancient medicinal plant with spasmolytic sesquiterpene esters. Two chemotypes, the petasine and the furanopetasine chemotype, occur in Austria. The first one is considered as pharmaceutically useful due to its spasmolytic constituents, but it is restricted to the northern parts of the Alps. This use, however, is impaired by the presence of low amounts of toxic pyrrolizidine alkaloids (PA), mainly senecionine and intergerrimine. PA are usually concentrated in the metabolically active parts of the complex rhizome which are the thickenings just below the leaves. They are also present in flower stalks but are almost absent in leaf buds, the petioles and the leaf blades. The alkaloids showed a great variability within and between populations; the values recorded ranged from less than 2 to 500mgkg(-1) PA, median PA of 77 populations varied from 2 to 191mgkg(-1) in the rhizomes. In nearly 25% of the samples analysed the PA content was below 10mgkg(-1), another 25% had between 10 and 20mgkg(-1) PA. Histograms of PA concentrations in a population often showed a distinct skewness toward lower alkaloid contents. Alkaloid content was independent of sesquiterpene chemotype. The seasonal influence on PA content of rhizomes was little in comparison to the variability within the population or within the rhizome itself. Nevertheless, when comparable rhizome parts within a population were considered, the PA content may remain stable over several years. Although plants totally free of PA could not yet be found, it is possible to select populations low in alkaloids. Several populations of the petasine chemotype containing less than 10mgkg(-1) in the rhizomes could be found in the area investigated.

Anti-tubulin drugs conjugated to anti-ErbB antibodies selectively radiosensitize.

PubMed

Adams, Stephen R; Yang, Howard C; Savariar, Elamprakash N; Aguilera, Joe; Crisp, Jessica L; Jones, Karra A; Whitney, Michael A; Lippman, Scott M; Cohen, Ezra E W; Tsien, Roger Y; Advani, Sunil J

2016-10-04

Tumour resistance to radiotherapy remains a barrier to improving cancer patient outcomes. To overcome radioresistance, certain drugs have been found to sensitize cells to ionizing radiation (IR). In theory, more potent radiosensitizing drugs should increase tumour kill and improve patient outcomes. In practice, clinical utility of potent radiosensitizing drugs is curtailed by off-target side effects. Here we report potent anti-tubulin drugs conjugated to anti-ErbB antibodies selectively radiosensitize to tumours based on surface receptor expression. While two classes of potent anti-tubulins, auristatins and maytansinoids, indiscriminately radiosensitize tumour cells, conjugating these potent anti-tubulins to anti-ErbB antibodies restrict their radiosensitizing capacity. Of translational significance, we report that a clinically used maytansinoid ADC, ado-trastuzumab emtansine (T-DM1), with IR prolongs tumour control in target expressing HER2+ tumours but not target negative tumours. In contrast to ErbB signal inhibition, our findings establish an alternative therapeutic paradigm for ErbB-based radiosensitization using antibodies to restrict radiosensitizer delivery.

Anti-tubulin drugs conjugated to anti-ErbB antibodies selectively radiosensitize

PubMed Central

Adams, Stephen R.; Yang, Howard C.; Savariar, Elamprakash N.; Aguilera, Joe; Crisp, Jessica L.; Jones, Karra A.; Whitney, Michael A.; Lippman, Scott M.; Cohen, Ezra E. W.; Tsien, Roger Y.; Advani, Sunil J.

2016-01-01

Tumour resistance to radiotherapy remains a barrier to improving cancer patient outcomes. To overcome radioresistance, certain drugs have been found to sensitize cells to ionizing radiation (IR). In theory, more potent radiosensitizing drugs should increase tumour kill and improve patient outcomes. In practice, clinical utility of potent radiosensitizing drugs is curtailed by off-target side effects. Here we report potent anti-tubulin drugs conjugated to anti-ErbB antibodies selectively radiosensitize to tumours based on surface receptor expression. While two classes of potent anti-tubulins, auristatins and maytansinoids, indiscriminately radiosensitize tumour cells, conjugating these potent anti-tubulins to anti-ErbB antibodies restrict their radiosensitizing capacity. Of translational significance, we report that a clinically used maytansinoid ADC, ado-trastuzumab emtansine (T-DM1), with IR prolongs tumour control in target expressing HER2+ tumours but not target negative tumours. In contrast to ErbB signal inhibition, our findings establish an alternative therapeutic paradigm for ErbB-based radiosensitization using antibodies to restrict radiosensitizer delivery. PMID:27698471

Recent Advances in the Medicinal Chemistry of the Metabotropic Glutamate Receptor 1 (mGlu1)

PubMed Central

2011-01-01

This Review summarizes the medicinal chemistry found in publications on both orthosteric and allosteric modulators of the metabotropic glutamate receptor 1 (mGlu1) from 2005 to the present. The time period covered by the scope of this current review has been particularly rich in mGlu1-related publications with numbers quadrupling when compared to the preceding five year period of 2000−2005. Publications in the field peaked in 2007 with over 35 articles appearing in the peer reviewed literature in the course of that year. Given that glutamate is one of the primary excitatory neurotransmitters in the mammalian central nervous system (CNS), it is unsurprising that it acts upon several receptors that are considered to be of potential therapeutic interest for many indications. Orthosteric and allosteric modulation of the receptor is possible, with a logical extrapolation to the chemotypes used for each strategy. The last five years of publications have yielded many mGlu1 selective antagonist chemotypyes, most of which have shown efficacy in pain in vivo models. However, the primary impact of these compounds has been to highlight the mechanistic safety risks of mGlu1 antagonism, independent of chemotype. As a review in medicinal chemistry, the primary focus of this paper will be on the design and, to a lesser degree, synthetic strategies for the delivery of subtype selective, CNS penetrant, druglike compounds through a “medchem” program, targeting modulators of the mGlu1 receptor. PMID:22860168

Detoxifying Escherichia coli for endotoxin-free production of recombinant proteins.

PubMed

Mamat, Uwe; Wilke, Kathleen; Bramhill, David; Schromm, Andra Beate; Lindner, Buko; Kohl, Thomas Andreas; Corchero, José Luis; Villaverde, Antonio; Schaffer, Lana; Head, Steven Robert; Souvignier, Chad; Meredith, Timothy Charles; Woodard, Ronald Wesley

2015-04-16

Lipopolysaccharide (LPS), also referred to as endotoxin, is the major constituent of the outer leaflet of the outer membrane of virtually all Gram-negative bacteria. The lipid A moiety, which anchors the LPS molecule to the outer membrane, acts as a potent agonist for Toll-like receptor 4/myeloid differentiation factor 2-mediated pro-inflammatory activity in mammals and, thus, represents the endotoxic principle of LPS. Recombinant proteins, commonly manufactured in Escherichia coli, are generally contaminated with endotoxin. Removal of bacterial endotoxin from recombinant therapeutic proteins is a challenging and expensive process that has been necessary to ensure the safety of the final product. As an alternative strategy for common endotoxin removal methods, we have developed a series of E. coli strains that are able to grow and express recombinant proteins with the endotoxin precursor lipid IVA as the only LPS-related molecule in their outer membranes. Lipid IVA does not trigger an endotoxic response in humans typical of bacterial LPS chemotypes. Hence the engineered cells themselves, and the purified proteins expressed within these cells display extremely low endotoxin levels. This paper describes the preparation and characterization of endotoxin-free E. coli strains, and demonstrates the direct production of recombinant proteins with negligible endotoxin contamination.

Specific Inhibition of Bacterial β-Glucuronidase by Pyrazolo[4,3-c]quinoline Derivatives via a pH-Dependent Manner To Suppress Chemotherapy-Induced Intestinal Toxicity.

PubMed

Cheng, Kai-Wen; Tseng, Chih-Hua; Yang, Chia-Ning; Tzeng, Cherng-Chyi; Cheng, Ta-Chun; Leu, Yu-Lin; Chuang, Yu-Chung; Wang, Jaw-Yuan; Lu, Yun-Chi; Chen, Yeh-Long; Cheng, Tian-Lu

2017-11-22

The direct inhibition of bacterial β-glucuronidase (βG) activity is expected to reduce the reactivation of glucuronide-conjugated drugs in the intestine, thereby reducing drug toxicity. In this study, we report on the effects of pyrazolo[4,3-c]quinolines acting as a new class of bacterial βG-specific inhibitors in a pH-dependent manner. Refinement of this chemotype for establishing structure-activity relationship resulted in the identification of potential leads. Notably, the oral administration of 3-amino-4-(4-fluorophenylamino)-1H-pyrazolo[4,3-c]quinoline (42) combined with chemotherapeutic CPT-11 treatment prevented CPT-11-induced serious diarrhea while maintaining the antitumor efficacy in tumor-bearing mice. Importantly, the inhibitory effects of 42 to E. coli βG was reduced as the pH decreased due to the various surface charges of the active pocket of the enzyme, which may make their combination more favorable at neutral pH. These results demonstrate novel insights into the potent bacterial βG-specific inhibitor that would allow this inhibitor to be used for the purpose of reducing drug toxicity.

Discovery of Highly Sweet Compounds from Natural Sources

NASA Astrophysics Data System (ADS)

Kinghorn, A. Douglas; Kennelly, Edward J.

1995-08-01

Sucrose, the most widely used sweetener globally, is of plant origin. In addition, a number of other plant constituents are employed as dietary sucrose substitutes in one or more countries, including the diterpenoid, stevioside, the triterpenoid, glycyrrhizin, and the protein, thaumatin. Accordingly, there has been much interest in discovering further examples of potently sweet compounds of natural origin, for potential use in foods, beverages, and medicines. Approximately 75 plant-derived compounds are presently known, mainly representative of the flavonoid, proanthocyandin, protein, steroidal saponin, and terpenoid chemotypes. In our program directed towards the elucidation of further highly sweet molecules from plants, candidate sweet-tasting plants for laboratory investigation are obtained from ethnobotanical observations in the field or in the existing literature. Examples of novel sweet-tasting compounds obtained so far are the sesquiterpenoids, hernandulcin and 4beta-hydroxyhemandulcin; the triterpenoids, abrusosides A-D; a semi-synthetic dihydroflavonol based on the naturally occurring substance, dihydroquercetin 3-acetate; and the proanthocyanidin, selligueain A. Natural product sweeteners may be of potential commercial use per se, and can be used for synthetic modification to produce improved sweeteners, and can also be of value scientifically to aid in the better understanding of structure-sweetness relationships.

Simultaneous Quantification of Forskolin and Iso-Forskolin in Coleus forskohlii (Wild.) Briq. and Identification of Elite Chemotype, Collected from Eastern Ghats (India)

PubMed Central

Shukla, Pushpendra Kumar; Misra, Ankita; Kumar, Manish; Jaichand; Singh, Kuldeep; Akhtar, Juber; Srivastava, Sharad; Agrawal, Pawan K; Singh Rawat, Ajay K

2017-01-01

Background: Coleus forskohlii is a well-known industrially important medicinal plant, for its high forskolin content. Objective: A simple, selective, and sensitive high-performance thin layer chromatography (HPTLC) method was developed and validated for simultaneous quantification of forskolin and iso-forskolin in C. forskohlii germplasm collected from the Eastern Ghats, India. Materials and Methods: Chromatographic separation of the targeted marker(s) was obtained on precoated silica plates using toluene: ethyl acetate: methanol (90:30:0.5, v/v/v) as the mobile phase. Results: Densitometric quantification of forskolin and iso-forskolin was carried out at 545 nm. Forskolin and iso-forskolin were identified by comparing the ultraviolet spectra of standard and sample track at Rf of 0.64 ± 0.02 and 0.36 ± 0.01, after derivatization with anisaldehyde sulfuric acid reagent. The linearity of both the analytes was obtained in the range of 300–1200 ng/spot with the regression coefficient (R2) of 0.991 and 0.986. Recovery of analyte (s) at three levels, namely, 100, 150, and 200 ng/spot was found to be 100.46% ± 0.29%, 99.64% ± 0.33%, 100.02% ± 0.76% and 99.76% ± 0.62%, 99.56% ± 0.35%, 100.02% ± 0.22%, respectively, for forskolin and iso-forskolin. The content of forskolin and iso-forskolin varies from 0.046% to 0.187% and 0.002% to 0.077%, respectively (dry weight basis), the maximum content of both the markers was found in NBC-31, from Thakurwada, Maharashtra. Conclusion: The developed HPTLC method was linear, accurate, and reliable as per the International Council for Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines. The study aids in the identification of elite chemotype for commercial prospection of industrially viable medicinal crop. SUMMARY 12 Samples are collected from different locations of the eastern ghat regionsQuantification of two major marker forskolin and iso forskolinThe maximum content of both the markers was found in NBC -31, from Thakurwada, MaharashtraIdentification of elite chemotype of collected samples may be useful for commercial prospection in industries. PMID:29491648

Discovery of Novel Inhibitors and Fluorescent Probe Targeting NAMPT.

PubMed

Wang, Xia; Xu, Tian-Ying; Liu, Xin-Zhu; Zhang, Sai-Long; Wang, Pei; Li, Zhi-Yong; Guan, Yun-Feng; Wang, Shu-Na; Dong, Guo-Qiang; Zhuo, Shu; Le, Ying-Ying; Sheng, Chun-Quan; Miao, Chao-Yu

2015-07-31

Nicotinamide phosphoribosyltransferase (NAMPT) is a promising antitumor target. Novel NAMPT inhibitors with diverse chemotypes are highly desirable for development of antitumor agents. Using high throughput screening system targeting NAMPT on a chemical library of 30000 small-molecules, we found a non-fluorescent compound F671-0003 and a fluorescent compound M049-0244 with excellent in vitro activity (IC50: 85 nM and 170 nM respectively) and anti-proliferative activity against HepG2 cells. These two compounds significantly depleted cellular NAD levels. Exogenous NMN rescued their anti-proliferative activity against HepG2 cells. Structure-activity relationship study proposed a binding mode for NAMPT inhibitor F671-0003 and highlighted the importance of hydrogen bonding, hydrophobic and π-π interactions in inhibitor binding. Imaging study provided the evidence that fluorescent compound M049-0244 (3 μM) significantly stained living HepG2 cells. Cellular fluorescence was further verified to be NAMPT dependent by using RNA interference and NAMPT over expression transgenic mice. Our findings provide novel antitumor lead compounds and a "first-in-class" fluorescent probe for imaging NAMPT.

Pharmacological validation of Trypanosoma brucei phosphodiesterases B1 and B2 as druggable targets for African sleeping sickness.

PubMed

Bland, Nicholas D; Wang, Cuihua; Tallman, Craig; Gustafson, Alden E; Wang, Zhouxi; Ashton, Trent D; Ochiana, Stefan O; McAllister, Gregory; Cotter, Kristina; Fang, Anna P; Gechijian, Lara; Garceau, Norman; Gangurde, Rajiv; Ortenberg, Ron; Ondrechen, Mary Jo; Campbell, Robert K; Pollastri, Michael P

2011-12-08

Neglected tropical disease drug discovery requires application of pragmatic and efficient methods for development of new therapeutic agents. In this report, we describe our target repurposing efforts for the essential phosphodiesterase (PDE) enzymes TbrPDEB1 and TbrPDEB2 of Trypanosoma brucei , the causative agent for human African trypanosomiasis (HAT). We describe protein expression and purification, assay development, and benchmark screening of a collection of 20 established human PDE inhibitors. We disclose that the human PDE4 inhibitor piclamilast, and some of its analogues, show modest inhibition of TbrPDEB1 and B2 and quickly kill the bloodstream form of the subspecies T. brucei brucei . We also report the development of a homology model of TbrPDEB1 that is useful for understanding the compound-enzyme interactions and for comparing the parasitic and human enzymes. Our profiling and early medicinal chemistry results strongly suggest that human PDE4 chemotypes represent a better starting point for optimization of TbrPDEB inhibitors than those that target any other human PDEs.

Recombinant yeast screen for new inhibitors of human acetyl-CoA carboxylase 2 identifies potential drugs to treat obesity

PubMed Central

Marjanovic, Jasmina; Chalupska, Dominika; Patenode, Caroline; Coster, Adam; Arnold, Evan; Ye, Alice; Anesi, George; Lu, Ying; Okun, Ilya; Tkachenko, Sergey; Haselkorn, Robert; Gornicki, Piotr

2010-01-01

Acetyl-CoA carboxylase (ACC) is a key enzyme of fatty acid metabolism with multiple isozymes often expressed in different eukaryotic cellular compartments. ACC-made malonyl-CoA serves as a precursor for fatty acids; it also regulates fatty acid oxidation and feeding behavior in animals. ACC provides an important target for new drugs to treat human diseases. We have developed an inexpensive nonradioactive high-throughput screening system to identify new ACC inhibitors. The screen uses yeast gene-replacement strains depending for growth on cloned human ACC1 and ACC2. In “proof of concept” experiments, growth of such strains was inhibited by compounds known to target human ACCs. The screen is sensitive and robust. Medium-size chemical libraries yielded new specific inhibitors of human ACC2. The target of the best of these inhibitors was confirmed with in vitro enzymatic assays. This compound is a new drug chemotype inhibiting human ACC2 with 2.8 μM IC50 and having no effect on human ACC1 at 100 μM. PMID:20439761

Chemical composition, plant genetic differences, and antifungal activity of the essential oil of Helichrysum italicum G. Don ssp. microphyllum (Willd) Nym.

PubMed

Angioni, Alberto; Barra, Andrea; Arlorio, Marco; Coisson, Jean Daniel; Russo, Maria T; Pirisi, Filippo M; Satta, Maurizio; Cabras, Paolo

2003-02-12

The chemical composition of the essential oil of the Sardinian dwarf curry plant [Helichrysum italicum G. Don ssp. microphyllum (Willd) Nym] was studied. Genetic analysis suggested the presence of two chemotypes; morphological and chemical differences confirmed the presence of two chemotypes (A and B). The maximum yields were 0.18 and 0.04% (v/w) for flowering tops and stems, respectively. The concentrations of nerol and its esters (acetate and propionate), limonene, and linalool reach their highest values during the flowering stage both in flowers and in stems. Besides the essential oil, type B showed an interesting antifungal activity.

Both gas chromatography and an electronic nose reflect chemical polymorphism of juniper shrubs browsed or avoided by sheep.

PubMed

Markó, Gábor; Novák, Ildikó; Bernáth, Jeno; Altbäcker, Vilmos

2011-07-01

Chemical polymorphism may contribute to variation in browsing damage by mammalian herbivores. Earlier, we demonstrated that essential oil concentration in juniper, Juniperus communis, was negatively associated with herbivore browsing. The aim of the present study was to characterize the volatile chemical composition of browsed and non-browsed J. communis. By using either gas chromatography with flame ionization detection (GC-FID) or an electronic nose device, we could separate sheep-browsed or non-browsed juniper shrubs by their essential oil pattern and complex odor matrix. The main components of the essential oil from J. communis were monoterpenes. We distinguished three chemotypes, dominated either by α-pinene, sabinene, or δ-3-carene. Shrubs belonging to the α-pinene- or sabinene-dominated groups were browsed, whereas all individuals with the δ-3-carene chemotype were unused by the local herbivores. The electronic nose also separated the browsed and non-browsed shrubs indicating that their odor matrix could guide sheep browsing. Responses of sheep could integrate the post-ingestive effects of plant secondary metabolites with sensory experience that stems from odor-phytotoxin interactions. Chemotype diversity could increase the survival rate in the present population of J. communis as certain shrubs could benefit from relatively better chemical protection against the herbivores.

Sesquiterpene lactones in Arnica montana: helenalin and dihydrohelenalin chemotypes in Spain.

PubMed

Perry, Nigel B; Burgess, Elaine J; Rodríguez Guitián, Manuel A; Romero Franco, Rosa; López Mosquera, Elvira; Smallfield, Bruce M; Joyce, Nigel I; Littlejohn, Roger P

2009-05-01

An analytical RPLC method for sesquiterpene lactones in Arnica montana has been extended to include quantitative analyses of dihydrohelenalin esters. LC-ESI-MS-MS distinguished the isomeric helenalin and dihydrohelenalin esters. The dihydrohelenalin esters have lower response factors for UV detection than do helenalin esters, which must be taken into account for quantitative analyses. Analyses of flowers from 16 different wild populations of A. montana in Spain showed differing proportions of helenalin and dihydrohelenalin esters. For the first time a chemotype with high levels of helenalin esters (total helenalins 5.2-10.3 mg/g dry weight) is reported in Spanish A. montana. These samples were from heath lands at high altitude (1330-1460 m), whereas samples from meadows and peat bogs at lower altitudes were the expected chemotype with high levels of dihydrohelenalin esters (total dihydrohelenalins 10.9-18.2 mg/g). The phenolic compounds, both flavonoid glycosides and caffeoylquinic acids, in Spanish A. montana are reported for the first time. The levels of several of these compounds differed significantly between samples from heath lands and samples from peat bogs or meadows, with the heath land samples being most similar to central European A. montana in their phenolic composition. Copyright Georg Thieme Verlag KG Stuttgart. New York.

Scaffold explorer: an interactive tool for organizing and mining structure-activity data spanning multiple chemotypes.

PubMed

Agrafiotis, Dimitris K; Wiener, John J M

2010-07-08

We introduce Scaffold Explorer, an interactive tool that allows medicinal chemists to define hierarchies of chemical scaffolds and use them to explore their project data. Scaffold Explorer allows the user to construct a tree, where each node corresponds to a specific scaffold. Each node can have multiple children, each of which represents a more refined substructure relative to its parent node. Once the tree is defined, it can be mapped onto any collection of compounds and be used as a navigational tool to explore structure-activity relationships (SAR) across different chemotypes. The rich visual analytics of Scaffold Explorer afford the user a "bird's-eye" view of the chemical space spanned by a particular data set, map any physicochemical property or biological activity of interest onto the individual scaffold nodes, serve as an aggregator for the properties of the compounds represented by these nodes, and quickly distinguish promising chemotypes from less interesting or problematic ones. Unlike previous approaches, which focused on automated extraction and classification of scaffolds, the utility of the new tool rests on its interactivity and ability to accommodate the medicinal chemists' intuition by allowing the use of arbitrary substructures containing variable atoms, bonds, and/or substituents such as those employed in substructure search.

Phylogenetic and Chemical Diversity of Three Chemotypes of Bloom-Forming Lyngbya Species (Cyanobacteria: Oscillatoriales) from Reefs of Southeastern Florida▿

PubMed Central

Sharp, Koty; Arthur, Karen E.; Gu, Liangcai; Ross, Cliff; Harrison, Genelle; Gunasekera, Sarath P.; Meickle, Theresa; Matthew, Susan; Luesch, Hendrik; Thacker, Robert W.; Sherman, David H.; Paul, Valerie J.

2009-01-01

The cyanobacterial genus Lyngbya includes free-living, benthic, filamentous cyanobacteria that form periodic nuisance blooms in lagoons, reefs, and estuaries. Lyngbya spp. are prolific producers of biologically active compounds that deter grazers and help blooms persist in the marine environment. Here, our investigations reveal the presence of three distinct Lyngbya species on nearshore reefs in Broward County, FL, sampled in 2006 and 2007. With a combination of morphological measurements, molecular biology techniques, and natural products chemistry, we associated these three Lyngbya species with three distinct Lyngbya chemotypes. One species, identified as Lyngbya cf. confervoides via morphological measurements and 16S rRNA gene sequencing, produces a diverse array of bioactive peptides and depsipeptides. Our results indicate that the other two Lyngbya species produce either microcolins A and B or curacin D and dragonamides C and D. Results from screening for the biosynthetic capacity for curacin production among the three Lyngbya chemotypes in this study correlated that capacity with the presence of curacin D. Our work on these bloom-forming Lyngbya species emphasizes the significant phylogenetic and chemical diversity of the marine cyanobacteria on southern Florida reefs and identifies some of the genetic components of those differences. PMID:19270119

Occurrence of Stachybotrys chartarum chemotype S in dried culinary herbs.

PubMed

Biermaier, Barbara; Gottschalk, Christoph; Schwaiger, Karin; Gareis, Manfred

2015-02-01

Stachybotrys (S.) chartarum is an omnipresent cellulolytic mould which produces secondary metabolites, such as the highly toxic macrocyclic trichothecenes. While it is known to occur in animal feed like hay and straw as well as in water-damaged indoor environments, there is little knowledge about the occurrence of S. chartarum and its secondary metabolites in food. The objective of the present study was to examine selected dried culinary herbs for the presence of S. chartarum chemotype S, to assess the potential risk of a contamination of foods with macrocyclic trichothecenes. In total, 50 Stachybotrys isolates from different types of culinary herbs (n=100) such as marjoram (Origanum majorana Linné (L.)), oregano (Origanum vulgare L.), thyme (Thymus vulgaris L.), and savory (Satureja hortensis L.) were examined by MTT-cell culture test (effect-based bioassay), ELISA, and by liquid chromatography tandem mass spectrometry (LC-MS/MS). Selected toxic and non-toxic isolates (n=15) were genetically characterized by PCR and sequencing. Five isolates (10%) were highly toxic in the MTT-cell culture test, and the production of macrocyclic trichothecenes was proven by ELISA and LC-MS/MS. These five isolates were genetically confirmed as S. chartarum chemotype S. To the best of our knowledge, this is the first report about a contamination of dried culinary herbs with toxigenic S. chartarum.

Towards New Antifolates Targeting Eukaryotic Opportunistic Infections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, J.; Bolstad, D; Bolstad, E

2009-01-01

Trimethoprim, an antifolate commonly prescribed in combination with sulfamethoxazole, potently inhibits several prokaryotic species of dihydrofolate reductase (DHFR). However, several eukaryotic pathogenic organisms are resistant to trimethoprim, preventing its effective use as a therapeutic for those infections. We have been building a program to reengineer trimethoprim to more potently and selectively inhibit eukaryotic species of DHFR as a viable strategy for new drug discovery targeting several opportunistic pathogens. We have developed a series of compounds that exhibit potent and selective inhibition of DHFR from the parasitic protozoa Cryptosporidium and Toxoplasma as well as the fungus Candida glabrata. A comparison ofmore » the structures of DHFR from the fungal species Candida glabrata and Pneumocystis suggests that the compounds may also potently inhibit Pneumocystis DHFR.« less

Distribution of Lutzomyia longipalpis chemotype populations in São Paulo state, Brazil.

PubMed

Casanova, Claudio; Colla-Jacques, Fernanda E; Hamilton, James G C; Brazil, Reginaldo P; Shaw, Jeffrey J

2015-03-01

American visceral leishmaniasis (AVL) is an emerging disease in the state of São Paulo, Brazil. Its geographical expansion and the increase in the number of human cases has been linked to dispersion of Lutzomyia longipalpis into urban areas. To produce more accurate risk maps we investigated the geographic distribution and routes of expansion of the disease as well as chemotype populations of the vector. A database, containing the annual records of municipalities which had notified human and canine AVL cases as well as the presence of the vector, was compiled. The chemotypes of L. longipalpis populations from municipalities in different regions of São Paulo State were determined by Coupled Gas Chromatography - Mass Spectrometry. From 1997 to June 2014, L. longipalpis has been reported in 166 municipalities, 148 of them in the Western region. A total of 106 municipalities were identified with transmission and 99 were located in the Western region, where all 2,204 autochthonous human cases occurred. Both the vector and the occurrence of human cases have expanded in a South-easterly direction, from the Western to central region, and from there, a further expansion to the North and the South. The (S)-9-methylgermacrene-B population of L. longipalpis is widely distributed in the Western region and the cembrene-1 population is restricted to the Eastern region. The maps in the present study show that there are two distinct epidemiological patterns of AVL in São Paulo State and that the expansion of human and canine AVL cases through the Western region has followed the same dispersion route of only one of the two species of the L. longipalpis complex, (S)-9-methylgermacrene-B. Entomological vigilance based on the routes of dispersion and identification of the chemotype population could be used to identify at-risk areas and consequently define the priorities for control measures.

Distribution of Lutzomyia longipalpis Chemotype Populations in São Paulo State, Brazil

PubMed Central

Casanova, Claudio; Colla-Jacques, Fernanda E.; Hamilton, James G. C.; Brazil, Reginaldo P.; Shaw, Jeffrey J.

2015-01-01

Background American visceral leishmaniasis (AVL) is an emerging disease in the state of São Paulo, Brazil. Its geographical expansion and the increase in the number of human cases has been linked to dispersion of Lutzomyia longipalpis into urban areas. To produce more accurate risk maps we investigated the geographic distribution and routes of expansion of the disease as well as chemotype populations of the vector. Methodology/Principal Findings A database, containing the annual records of municipalities which had notified human and canine AVL cases as well as the presence of the vector, was compiled. The chemotypes of L. longipalpis populations from municipalities in different regions of São Paulo State were determined by Coupled Gas Chromatography – Mass Spectrometry. From 1997 to June 2014, L. longipalpis has been reported in 166 municipalities, 148 of them in the Western region. A total of 106 municipalities were identified with transmission and 99 were located in the Western region, where all 2,204 autochthonous human cases occurred. Both the vector and the occurrence of human cases have expanded in a South-easterly direction, from the Western to central region, and from there, a further expansion to the North and the South. The (S)-9-methylgermacrene-B population of L. longipalpis is widely distributed in the Western region and the cembrene-1 population is restricted to the Eastern region. Conclusion/Significance The maps in the present study show that there are two distinct epidemiological patterns of AVL in São Paulo State and that the expansion of human and canine AVL cases through the Western region has followed the same dispersion route of only one of the two species of the L. longipalpis complex, (S)-9-methylgermacrene-B. Entomological vigilance based on the routes of dispersion and identification of the chemotype population could be used to identify at-risk areas and consequently define the priorities for control measures. PMID:25781320

Sexuality Generates Diversity in the Aflatoxin Gene Cluster: Evidence on a Global Scale

PubMed Central

Moore, Geromy G.; Elliott, Jacalyn L.; Singh, Rakhi; Horn, Bruce W.; Dorner, Joe W.; Stone, Eric A.; Chulze, Sofia N.; Barros, German G.; Naik, Manjunath K.; Wright, Graeme C.; Hell, Kerstin; Carbone, Ignazio

2013-01-01

Aflatoxins are produced by Aspergillus flavus and A. parasiticus in oil-rich seed and grain crops and are a serious problem in agriculture, with aflatoxin B1 being the most carcinogenic natural compound known. Sexual reproduction in these species occurs between individuals belonging to different vegetative compatibility groups (VCGs). We examined natural genetic variation in 758 isolates of A. flavus, A. parasiticus and A. minisclerotigenes sampled from single peanut fields in the United States (Georgia), Africa (Benin), Argentina (Córdoba), Australia (Queensland) and India (Karnataka). Analysis of DNA sequence variation across multiple intergenic regions in the aflatoxin gene clusters of A. flavus, A. parasiticus and A. minisclerotigenes revealed significant linkage disequilibrium (LD) organized into distinct blocks that are conserved across different localities, suggesting that genetic recombination is nonrandom and a global occurrence. To assess the contributions of asexual and sexual reproduction to fixation and maintenance of toxin chemotype diversity in populations from each locality/species, we tested the null hypothesis of an equal number of MAT1-1 and MAT1-2 mating-type individuals, which is indicative of a sexually recombining population. All samples were clone-corrected using multi-locus sequence typing which associates closely with VCG. For both A. flavus and A. parasiticus, when the proportions of MAT1-1 and MAT1-2 were significantly different, there was more extensive LD in the aflatoxin cluster and populations were fixed for specific toxin chemotype classes, either the non-aflatoxigenic class in A. flavus or the B1-dominant and G1-dominant classes in A. parasiticus. A mating type ratio close to 1∶1 in A. flavus, A. parasiticus and A. minisclerotigenes was associated with higher recombination rates in the aflatoxin cluster and less pronounced chemotype differences in populations. This work shows that the reproductive nature of the population (more sexual versus more asexual) is predictive of aflatoxin chemotype diversity in these agriculturally important fungi. PMID:24009506

Enhancing bioactive peptide release and identification using targeted enzymatic hydrolysis of milk proteins.

PubMed

Nongonierma, Alice B; FitzGerald, Richard J

2018-06-01

Milk proteins have been extensively studied for their ability to yield a range of bioactive peptides following enzymatic hydrolysis/digestion. However, many hurdles still exist regarding the widespread utilization of milk protein-derived bioactive peptides as health enhancing agents for humans. These mostly arise from the fact that most milk protein-derived bioactive peptides are not highly potent. In addition, they may be degraded during gastrointestinal digestion and/or have a low intestinal permeability. The targeted release of bioactive peptides during the enzymatic hydrolysis of milk proteins may allow the generation of particularly potent bioactive hydrolysates and peptides. Therefore, the development of milk protein hydrolysates capable of improving human health requires, in the first instance, optimized targeted release of specific bioactive peptides. The targeted hydrolysis of milk proteins has been aided by a range of in silico tools. These include peptide cutters and predictive modeling linking bioactivity to peptide structure [i.e., molecular docking, quantitative structure activity relationship (QSAR)], or hydrolysis parameters [design of experiments (DOE)]. Different targeted enzymatic release strategies employed during the generation of milk protein hydrolysates are reviewed herein and their limitations are outlined. In addition, specific examples are provided to demonstrate how in silico tools may help in the identification and discovery of potent milk protein-derived peptides. It is anticipated that the development of novel strategies employing a range of in silico tools may help in the generation of milk protein hydrolysates containing potent and bioavailable peptides, which in turn may be used to validate their health promoting effects in humans. Graphical abstract The targeted enzymatic hydrolysis of milk proteins may allow the generation of highly potent and bioavailable bioactive peptides.

μ Opioid receptor: novel antagonists and structural modeling

NASA Astrophysics Data System (ADS)

Kaserer, Teresa; Lantero, Aquilino; Schmidhammer, Helmut; Spetea, Mariana; Schuster, Daniela

2016-02-01

The μ opioid receptor (MOR) is a prominent member of the G protein-coupled receptor family and the molecular target of morphine and other opioid drugs. Despite the long tradition of MOR-targeting drugs, still little is known about the ligand-receptor interactions and structure-function relationships underlying the distinct biological effects upon receptor activation or inhibition. With the resolved crystal structure of the β-funaltrexamine-MOR complex, we aimed at the discovery of novel agonists and antagonists using virtual screening tools, i.e. docking, pharmacophore- and shape-based modeling. We suggest important molecular interactions, which active molecules share and distinguish agonists and antagonists. These results allowed for the generation of theoretically validated in silico workflows that were employed for prospective virtual screening. Out of 18 virtual hits evaluated in in vitro pharmacological assays, three displayed antagonist activity and the most active compound significantly inhibited morphine-induced antinociception. The new identified chemotypes hold promise for further development into neurochemical tools for studying the MOR or as potential therapeutic lead candidates.

Nannocystin A: an Elongation Factor 1 Inhibitor from Myxobacteria with Differential Anti-Cancer Properties.

PubMed

Krastel, Philipp; Roggo, Silvio; Schirle, Markus; Ross, Nathan T; Perruccio, Francesca; Aspesi, Peter; Aust, Thomas; Buntin, Kathrin; Estoppey, David; Liechty, Brigitta; Mapa, Felipa; Memmert, Klaus; Miller, Howard; Pan, Xuewen; Riedl, Ralph; Thibaut, Christian; Thomas, Jason; Wagner, Trixie; Weber, Eric; Xie, Xiaobing; Schmitt, Esther K; Hoepfner, Dominic

2015-08-24

Cultivation of myxobacteria of the Nannocystis genus led to the isolation and structure elucidation of a class of novel cyclic lactone inhibitors of elongation factor 1. Whole genome sequence analysis and annotation enabled identification of the putative biosynthetic cluster and synthesis process. In biological assays the compounds displayed anti-fungal and cytotoxic activity. Combined genetic and proteomic approaches identified the eukaryotic translation elongation factor 1α (EF-1α) as the primary target for this compound class. Nannocystin A (1) displayed differential activity across various cancer cell lines and EEF1A1 expression levels appear to be the main differentiating factor. Biochemical and genetic evidence support an overlapping binding site of 1 with the anti-cancer compound didemnin B on EF-1α. This myxobacterial chemotype thus offers an interesting starting point for further investigations of the potential of therapeutics targeting elongation factor 1. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Directory of Useful Decoys, Enhanced (DUD-E): Better Ligands and Decoys for Better Benchmarking

PubMed Central

2012-01-01

A key metric to assess molecular docking remains ligand enrichment against challenging decoys. Whereas the directory of useful decoys (DUD) has been widely used, clear areas for optimization have emerged. Here we describe an improved benchmarking set that includes more diverse targets such as GPCRs and ion channels, totaling 102 proteins with 22886 clustered ligands drawn from ChEMBL, each with 50 property-matched decoys drawn from ZINC. To ensure chemotype diversity, we cluster each target’s ligands by their Bemis–Murcko atomic frameworks. We add net charge to the matched physicochemical properties and include only the most dissimilar decoys, by topology, from the ligands. An online automated tool (http://decoys.docking.org) generates these improved matched decoys for user-supplied ligands. We test this data set by docking all 102 targets, using the results to improve the balance between ligand desolvation and electrostatics in DOCK 3.6. The complete DUD-E benchmarking set is freely available at http://dude.docking.org. PMID:22716043

Enabling Large-Scale Design, Synthesis and Validation of Small Molecule Protein-Protein Antagonists

PubMed Central

Koes, David; Khoury, Kareem; Huang, Yijun; Wang, Wei; Bista, Michal; Popowicz, Grzegorz M.; Wolf, Siglinde; Holak, Tad A.; Dömling, Alexander; Camacho, Carlos J.

2012-01-01

Although there is no shortage of potential drug targets, there are only a handful known low-molecular-weight inhibitors of protein-protein interactions (PPIs). One problem is that current efforts are dominated by low-yield high-throughput screening, whose rigid framework is not suitable for the diverse chemotypes present in PPIs. Here, we developed a novel pharmacophore-based interactive screening technology that builds on the role anchor residues, or deeply buried hot spots, have in PPIs, and redesigns these entry points with anchor-biased virtual multicomponent reactions, delivering tens of millions of readily synthesizable novel compounds. Application of this approach to the MDM2/p53 cancer target led to high hit rates, resulting in a large and diverse set of confirmed inhibitors, and co-crystal structures validate the designed compounds. Our unique open-access technology promises to expand chemical space and the exploration of the human interactome by leveraging in-house small-scale assays and user-friendly chemistry to rationally design ligands for PPIs with known structure. PMID:22427896

Identification of novel 2-benzoxazolinone derivatives with specific inhibitory activity against the HIV-1 nucleocapsid protein.

PubMed

Gamba, Elia; Mori, Mattia; Kovalenko, Lesia; Giannini, Alessia; Sosic, Alice; Saladini, Francesco; Fabris, Dan; Mély, Yves; Gatto, Barbara; Botta, Maurizio

2018-02-10

In this report, we present a new benzoxazole derivative endowed with inhibitory activity against the HIV-1 nucleocapsid protein (NC). NC is a 55-residue basic protein with nucleic acid chaperone properties, which has emerged as a novel and potential pharmacological target against HIV-1. In the pursuit of novel NC-inhibitor chemotypes, we performed virtual screening and in vitro biological evaluation of a large library of chemical entities. We found that compounds sharing a benzoxazolinone moiety displayed putative inhibitory properties, which we further investigated by considering a series of chemical analogues. This approach provided valuable information on the structure-activity relationships of these compounds and, in the process, demonstrated that their anti-NC activity could be finely tuned by the addition of specific substituents to the initial benzoxazolinone scaffold. This study represents the starting point for the possible development of a new class of antiretroviral agents targeting the HIV-1 NC protein. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Multi-Layer Identification of Highly-Potent ABCA1 Up-Regulators Targeting LXRβ Using Multiple QSAR Modeling, Structural Similarity Analysis, and Molecular Docking.

PubMed

Chen, Meimei; Yang, Fafu; Kang, Jie; Yang, Xuemei; Lai, Xinmei; Gao, Yuxing

2016-11-29

In this study, in silico approaches, including multiple QSAR modeling, structural similarity analysis, and molecular docking, were applied to develop QSAR classification models as a fast screening tool for identifying highly-potent ABCA1 up-regulators targeting LXRβ based on a series of new flavonoids. Initially, four modeling approaches, including linear discriminant analysis, support vector machine, radial basis function neural network, and classification and regression trees, were applied to construct different QSAR classification models. The statistics results indicated that these four kinds of QSAR models were powerful tools for screening highly potent ABCA1 up-regulators. Then, a consensus QSAR model was developed by combining the predictions from these four models. To discover new ABCA1 up-regulators at maximum accuracy, the compounds in the ZINC database that fulfilled the requirement of structural similarity of 0.7 compared to known potent ABCA1 up-regulator were subjected to the consensus QSAR model, which led to the discovery of 50 compounds. Finally, they were docked into the LXRβ binding site to understand their role in up-regulating ABCA1 expression. The excellent binding modes and docking scores of 10 hit compounds suggested they were highly-potent ABCA1 up-regulators targeting LXRβ. Overall, this study provided an effective strategy to discover highly potent ABCA1 up-regulators.

Simultaneous inhibition of multiple oncogenic miRNAs by a multi-potent microRNA sponge.

PubMed

Jung, Jaeyun; Yeom, Chanjoo; Choi, Yeon-Sook; Kim, Sinae; Lee, EunJi; Park, Min Ji; Kang, Sang Wook; Kim, Sung Bae; Chang, Suhwan

2015-08-21

The roles of oncogenic miRNAs are widely recognized in many cancers. Inhibition of single miRNA using antagomiR can efficiently knock-down a specific miRNA. However, the effect is transient and often results in subtle phenotype, as there are other miRNAs contribute to tumorigenesis. Here we report a multi-potent miRNA sponge inhibiting multiple miRNAs simultaneously. As a model system, we targeted miR-21, miR-155 and miR-221/222, known as oncogenic miRNAs in multiple tumors including breast and pancreatic cancers. To achieve efficient knockdown, we generated perfect and bulged-matched miRNA binding sites (MBS) and introduced multiple copies of MBS, ranging from one to five, in the multi-potent miRNA sponge. Luciferase reporter assay showed the multi-potent miRNA sponge efficiently inhibited 4 miRNAs in breast and pancreatic cancer cells. Furthermore, a stable and inducible version of the multi-potent miRNA sponge cell line showed the miRNA sponge efficiently reduces the level of 4 target miRNAs and increase target protein level of these oncogenic miRNAs. Finally, we showed the miRNA sponge sensitize cells to cancer drug and attenuate cell migratory activity. Altogether, our study demonstrates the multi-potent miRNA sponge is a useful tool to examine the functional impact of simultaneous inhibition of multiple miRNAs and proposes a therapeutic potential.

Total NMR assignments of new [C7-O-C7'']-biflavones from leaves of the limonene-carvone chemotype of Lippia alba (Mill) N. E. Brown.

PubMed

Barbosa, Francisco Geraldo; Lima, Mary Anne Sousa; Silveira, Edilberto Rocha

2005-04-01

Phytochemical analysis of leaves of the limonene-carvone chemotype of Lippia alba led to the isolation of two biflavonoids with a new structural pattern with an ether linkage: 5,5''-dihydroxy-6,4',6'',3''',4'''-pentamethoxy-[C(7)--O--C(7'')]-biflavone (1) and 4',4,5,5''-tetrahydroxy-6,6'',3'''-trimethoxy-[C(7)--O--C(7'')]-biflavone (2). Structural elucidation of the new compounds was established on the basis of spectral data, through the use of 1D NMR and several 2D shift correlated NMR pulse sequences (COSY, HMQC, HMBC and NOESY). Copyright (c) 2005 John Wiley & Sons, Ltd

Metabolite profiles of Stachybotrys isolates from water-damaged buildings and their induction of inflammatory mediators and cytotoxicity in macrophages.

PubMed

Nielsen, Kristian Fog; Huttunen, Kati; Hyvärinen, Anne; Andersen, Birgitte; Jarvis, Bruce B; Hirvonen, Maija-Riitta

2002-01-01

The metabolite profiles of 20 Stachybotrys spp. isolates from Finnish water-damaged buildings were compared with their biological activities. Effects of purified compounds on cytotoxicity and production of inflammatory mediators such as nitric oxide, IL-6 and TNFalpha in murine RAW264.7 macrophage cells were studied. The 11 isolates belonging to the satratoxin-producing chemotype were highly cytotoxic to the macrophages. The isolates inducing inflammatory mediators all belonged to the atranone-producing chemotype, but pure atranones B, and D did not elicit a response in the bioassay. Altogether, cytotoxicity of Stachybotrys sp. isolates appear to be related to satratoxin production whereas the specific component inducing inflammatory responses in atranone-producing isolates remains obscure.

Discovery of a novel, CNS penetrant M4 PAM chemotype based on a 6-fluoro-4-(piperidin-1-yl)quinoline-3-carbonitrile core.

PubMed

Bewley, Blake R; Spearing, Paul K; Weiner, Rebecca L; Luscombe, Vincent B; Zhan, Xiaoyan; Chang, Sichen; Cho, Hyekyung P; Rodriguez, Alice L; Niswender, Colleen M; Conn, P Jeffrey; Bridges, Thomas M; Engers, Darren W; Lindsley, Craig W

2017-09-15

This Letter details the discovery and subsequent optimization of a novel M 4 PAM scaffold based on an 6-fluoro-4-(piperidin-1-yl)quinoline-3-carbonitrile core, which represents a distinct departure from the classical M 4 PAM chemotypes. Optimized compounds in this series demonstrated improved M 4 PAM potency on both human and rat M 4 (4 to 5-fold relative to HTS hit), and displayed attractive physicochemical and DMPK profiles, including good CNS penetration (rat brain:plasma K p =5.3, K p,uu =2.4; MDCK-MDR1 (P-gp) ER=1.1). Copyright © 2017 Elsevier Ltd. All rights reserved.

Efforts towards the optimization of a bi-aryl class of potent IRAK4 inhibitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanisak, Jennifer; Seganish, W. Michael; McElroy, William T.

2016-09-01

IRAK4 has been identified as potential therapeutic target for inflammatory and autoimmune diseases. Herein we report the identification and initial SAR studies of a new class of pyrazole containing IRAK4 inhibitors designed to expand chemical diversity and improve off target activity of a previously identified series. These compounds maintain potent IRAK4 activity and desirable ligand efficiency. Rat clearance and a variety of off target activities were also examined, resulting in encouraging data with tractable SAR.

Crystal structures of ASK1-inhibtor complexes provide a platform for structure-based drug design

PubMed Central

Singh, Onkar; Shillings, Anthony; Craggs, Peter; Wall, Ian; Rowland, Paul; Skarzynski, Tadeusz; Hobbs, Clare I; Hardwick, Phil; Tanner, Rob; Blunt, Michelle; Witty, David R; Smith, Kathrine J

2013-01-01

ASK1, a member of the MAPK Kinase Kinase family of proteins has been shown to play a key role in cancer, neurodegeneration and cardiovascular diseases and is emerging as a possible drug target. Here we describe a ‘replacement-soaking’ method that has enabled the high-throughput X-ray structure determination of ASK1/ligand complexes. Comparison of the X-ray structures of five ASK1/ligand complexes from 3 different chemotypes illustrates that the ASK1 ATP binding site is able to accommodate a range of chemical diversity and different binding modes. The replacement-soaking system is also able to tolerate some protein flexibility. This crystal system provides a robust platform for ASK1/ligand structure determination and future structure based drug design. PMID:23776076

Photochemical Approaches to Complex Chemotypes: Applications in Natural Product Synthesis.

PubMed

Kärkäs, Markus D; Porco, John A; Stephenson, Corey R J

2016-09-14

The use of photochemical transformations is a powerful strategy that allows for the formation of a high degree of molecular complexity from relatively simple building blocks in a single step. A central feature of all light-promoted transformations is the involvement of electronically excited states, generated upon absorption of photons. This produces transient reactive intermediates and significantly alters the reactivity of a chemical compound. The input of energy provided by light thus offers a means to produce strained and unique target compounds that cannot be assembled using thermal protocols. This review aims at highlighting photochemical transformations as a tool for rapidly accessing structurally and stereochemically diverse scaffolds. Synthetic designs based on photochemical transformations have the potential to afford complex polycyclic carbon skeletons with impressive efficiency, which are of high value in total synthesis.

Insecticidal activity of Piper essential oils from the Amazon against the fire ant Solenopsis saevissima (Smith) (Hymenoptera: Formicidae).

PubMed

Souto, R N P; Harada, A Y; Andrade, E H A; Maia, J G S

2012-12-01

Pepper plants in the genus Piper (Piperales: Piperaceae) are common in the Brazilian Amazon and many produce compounds with biological activity against insect pests. We evaluated the insecticidal effect of essential oils from Piper aduncum, Piper marginatum (chemotypes A and B), Piper divaricatum and Piper callosum against workers of the fire ant Solenopsis saevissima (Smith) (Hymenoptera: Formicidae), as well as their chemical composition by gas chromatography and gas chromatography-mass spectrometry. The lowest median lethal concentration (LC50) in 48 h was obtained with the oil of P. aduncum (58.4 mg/L), followed by the oils of P. marginatum types A (122.4 mg/L) and B (167.0 mg/L), P. divaricatum (301.7 mg/L), and P. callosum (312.6 mg/L). The major chemical constituents were dillapiole (64.4%) in the oil of P. aduncum; p-mentha-1(7),8-diene (39.0%), 3,4-methylenedioxypropiophenone (19.0%), and (E)-β-ocimene (9.8%) in P. marginatum chemotype A and (E)-isoosmorhizole (32.2%), (E)-anethole (26.4%), isoosmorhizole (11.2%), and (Z)-anethole (6.0%) in P. marginatum chemotype B; methyleugenol (69.2%) and eugenol (16.2%) in P. divaricatum; and safrole (69.2%), methyleugenol (8.6%), and β-pinene (6.2%) in P. callosum. These chemical constituents have been previously known to possess insecticidal properties.

Essential Oil Composition of Valeriana Jatamansi Jones from Himalayan Regions of India

PubMed Central

Raina, Archana P.; Negi, K. S.

2015-01-01

Valeriana jatamansi Jones germplasm collected from sub-temperate Himalayan region of Uttarakhand and North-East state of Meghalaya, India was evaluated under identical conditions at National Bureau of Plant Genetic Resources, Bhowali, India, to study germplasm diversity based on essential oil composition. Twenty one compounds were identified in V. jatamansi root oil by GC and GC-MS. The major compounds identified were patchouli alcohol (0.4-63.7%), maaliol (2.9-53.8%), seychellene (4.1-27.4%), calarene/ß-gurjunene (3.0-20.8%), α-santalene (0.6-12.0%). Other compounds present were bornyl acetate (0.6-1.5%), α-guaiene (0.7-2.3%), α-bulnesene/δ-guaiene (0.7-6.3%), 7-epi-α-selinene (0.4-1.4%), kessane (2.1-3.3%), spathulenol (0.7-3.4%), viridiflorol (0.9-7.1%), α-patchoulene (0.8-6.6%), ß-patchoulene (0.4-0.8%). Two superior chemotypes identified in V. jatamansi oil from Uttarakhand were: patchouli alcohol rich (IC573221, 63.7%) and maaliol rich (IC573222, 53.8%; IC589096, 51.7%), while accession from north-east was patchouli alcohol rich chemotype (IC574522, 57.2%). These superior chemotypes with higher amounts of patchouli alcohol and maaliol could be used for promoting cultivation as well as for meeting need of pharmaceutical industries. PMID:26009656

Development of Potent Antiviral Drugs Inspired by Viral Hexameric DNA-Packaging Motors with Revolving Mechanism

PubMed Central

Pi, Fengmei; Zhao, Zhengyi; Chelikani, Venkata; Yoder, Kristine; Kvaratskhelia, Mamuka

2016-01-01

The intracellular parasitic nature of viruses and the emergence of antiviral drug resistance necessitate the development of new potent antiviral drugs. Recently, a method for developing potent inhibitory drugs by targeting biological machines with high stoichiometry and a sequential-action mechanism was described. Inspired by this finding, we reviewed the development of antiviral drugs targeting viral DNA-packaging motors. Inhibiting multisubunit targets with sequential actions resembles breaking one bulb in a series of Christmas lights, which turns off the entire string. Indeed, studies on viral DNA packaging might lead to the development of new antiviral drugs. Recent elucidation of the mechanism of the viral double-stranded DNA (dsDNA)-packaging motor with sequential one-way revolving motion will promote the development of potent antiviral drugs with high specificity and efficiency. Traditionally, biomotors have been classified into two categories: linear and rotation motors. Recently discovered was a third type of biomotor, including the viral DNA-packaging motor, beside the bacterial DNA translocases, that uses a revolving mechanism without rotation. By analogy, rotation resembles the Earth's rotation on its own axis, while revolving resembles the Earth's revolving around the Sun (see animations at http://rnanano.osu.edu/movie.html). Herein, we review the structures of viral dsDNA-packaging motors, the stoichiometries of motor components, and the motion mechanisms of the motors. All viral dsDNA-packaging motors, including those of dsDNA/dsRNA bacteriophages, adenoviruses, poxviruses, herpesviruses, mimiviruses, megaviruses, pandoraviruses, and pithoviruses, contain a high-stoichiometry machine composed of multiple components that work cooperatively and sequentially. Thus, it is an ideal target for potent drug development based on the power function of the stoichiometries of target complexes that work sequentially. PMID:27356896

Design of Potent and Druglike Nonphenolic Inhibitors for Catechol O-Methyltransferase Derived from a Fragment Screening Approach Targeting the S-Adenosyl-l-methionine Pocket.

PubMed

Lerner, Christian; Jakob-Roetne, Roland; Buettelmann, Bernd; Ehler, Andreas; Rudolph, Markus; Rodríguez Sarmiento, Rosa María

2016-11-23

A fragment screening approach designed to target specifically the S-adenosyl-l-methionine pocket of catechol O-methyl transferase allowed the identification of structurally related fragments of high ligand efficiency and with activity on the described orthogonal assays. By use of a reliable enzymatic assay together with X-ray crystallography as guidance, a series of fragment modifications revealed an SAR and, after several expansions, potent lead compounds could be obtained. For the first time nonphenolic and small low nanomolar potent, SAM competitive COMT inhibitors are reported. These compounds represent a novel series of potent COMT inhibitors that might be further optimized to new drugs useful for the treatment of Parkinson's disease, as adjuncts in levodopa based therapy, or for the treatment of schizophrenia.

Mountain pine beetle attack associated with low levels of 4-allylanisole in ponderosa pine.

PubMed

Emerick, Jay J; Snyder, Aaron I; Bower, Nathan W; Snyder, Marc A

2008-08-01

Mountain pine beetle (Dendroctonus ponderosae) is the most important insect pest in southern Rocky Mountain ponderosa pine (Pinus ponderosa) forests. Tree mortality is hastened by the various fungal pathogens that are symbiotic with the beetles. The phenylpropanoid 4-allylanisole is an antifungal and semiochemical for some pine beetle species. We analyzed 4-allylanisole and monoterpene profiles in the xylem oleoresin from a total of 107 trees at six sites from two chemotypes of ponderosa pine found in Colorado and New Mexico using gas chromatography-mass spectroscopy (GC-MS). Although monoterpene profiles were essentially the same in attacked and nonattacked trees, significantly lower levels of 4-allylanisole were found in attacked trees compared with trees that showed no evidence of attack for both chemotypes.

Identification of novel selective V2 receptor non-peptide agonists.

PubMed

Del Tredici, Andria L; Vanover, Kim E; Knapp, Anne E; Bertozzi, Sine M; Nash, Norman R; Burstein, Ethan S; Lameh, Jelveh; Currier, Erika A; Davis, Robert E; Brann, Mark R; Mohell, Nina; Olsson, Roger; Piu, Fabrice

2008-10-30

Peptides with agonist activity at the vasopressin V(2) receptor are used clinically to treat fluid homeostasis disorders such as polyuria and central diabetes insipidus. Of these peptides, the most commonly used is desmopressin, which displays poor bioavailability as well as potent activity at the V(1b) receptor, with possible stress-related adverse effects. Thus, there is a strong need for the development of small molecule chemistries with selective V(2) receptor agonist activity. Using the functional cell-based assay Receptor Selection and Amplification Technology (R-SAT((R))), a screening effort identified three small molecule chemotypes (AC-94544, AC-88324, and AC-110484) with selective agonist activity at the V(2) receptor. One of these compounds, AC-94544, displayed over 180-fold selectivity at the V(2) receptor compared to related vasopressin and oxytocin receptors and no activity at 28 other G protein-coupled receptors (GPCRs). All three compounds also showed partial agonist activity at the V(2) receptor in a cAMP accumulation assay. In addition, in a rat model of central diabetes insipidus, AC-94544 was able to significantly reduce urine output in a dose-dependent manner. Thus, AC-94544, AC-88324, and AC-110484 represent novel opportunities for the treatment of disorders associated with V(2) receptor agonist deficiency.

Lepidopteran HMG-CoA reductase is a potential selective target for pest control

PubMed Central

Li, Yuan-mei; Huang, Juan; Tobe, Stephen S.

2017-01-01

As a consequence of the negative impacts on the environment of some insecticides, discovery of eco-friendly insecticides and target has received global attention in recent years. Sequence alignment and structural comparison of the rate-limiting enzyme HMG-CoA reductase (HMGR) revealed differences between lepidopteran pests and other organisms, which suggested insect HMGR could be a selective insecticide target candidate. Inhibition of JH biosynthesis in vitro confirmed that HMGR inhibitors showed a potent lethal effect on the lepidopteran pest Manduca sexta, whereas there was little effect on JH biosynthesis in Apis mellifera and Diploptera punctata. The pest control application of these inhibitors demonstrated that they can be insecticide candidates with potent ovicidal activity, larvicidal activity and insect growth regulatory effects. The present study has validated that Lepidopteran HMGR can be a potent selective insecticide target, and the HMGR inhibitors (especially type II statins) could be selective insecticide candidates and lead compounds. Furthermore, we demonstrated that sequence alignment, homology modeling and structural comparison may be useful for determining potential enzymes or receptors which can be eco-friendly pesticide  targets. PMID:28133568

Lepidopteran HMG-CoA reductase is a potential selective target for pest control.

PubMed

Li, Yuan-Mei; Kai, Zhen-Peng; Huang, Juan; Tobe, Stephen S

2017-01-01

As a consequence of the negative impacts on the environment of some insecticides, discovery of eco-friendly insecticides and target has received global attention in recent years. Sequence alignment and structural comparison of the rate-limiting enzyme HMG-CoA reductase (HMGR) revealed differences between lepidopteran pests and other organisms, which suggested insect HMGR could be a selective insecticide target candidate. Inhibition of JH biosynthesis in vitro confirmed that HMGR inhibitors showed a potent lethal effect on the lepidopteran pest Manduca sexta , whereas there was little effect on JH biosynthesis in Apis mellifera and Diploptera punctata . The pest control application of these inhibitors demonstrated that they can be insecticide candidates with potent ovicidal activity, larvicidal activity and insect growth regulatory effects. The present study has validated that Lepidopteran HMGR can be a potent selective insecticide target, and the HMGR inhibitors (especially type II statins) could be selective insecticide candidates and lead compounds. Furthermore, we demonstrated that sequence alignment, homology modeling and structural comparison may be useful for determining potential enzymes or receptors which can be eco-friendly pesticide  targets.

Chance and design in proinsecticide discovery.

PubMed

Salgado, Vincent L; David, Michael D

2017-04-01

Many insecticides are inactive on their target sites in the form that is sold and applied, needing first to be bioactivated. This proinsecticide strategy has often been achieved by design, through systematic derivatization of intrinsically active molecules with protecting groups that mask their toxic effects until their selective removal in target insects by metabolic enzymes generates the toxiphore. Proinsecticides can be designed to gain selectivity between target and non-target organisms, or to improve bioavailability by enhancing plant or insect uptake. In most cases, however, chance trumps design in proinsecticide discovery: most first-in-class products that we now know to be proinsecticides were only discovered a posteriori to be such, often after having been on the market for years. Knowing the active form of an insecticide is essential to mode of action identification, and early mode of action studies on novel chemotypes should take into account the possibility that the compounds might be proinsecticides. This paper reviews examples of proinsecticides in the marketplace, strategies for making proinsecticides and techniques for unmasking proinsecticides in mode of action studies. Our analysis of global agrochemical sales data shows that 34% of the dollar value of crop insecticides used in 2015 were proinsecticides. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Structure-Based Virtual Ligand Screening on the XRCC4/DNA Ligase IV Interface

NASA Astrophysics Data System (ADS)

Menchon, Grégory; Bombarde, Oriane; Trivedi, Mansi; Négrel, Aurélie; Inard, Cyril; Giudetti, Brigitte; Baltas, Michel; Milon, Alain; Modesti, Mauro; Czaplicki, Georges; Calsou, Patrick

2016-03-01

The association of DNA Ligase IV (Lig4) with XRCC4 is essential for repair of DNA double-strand breaks (DSBs) by Non-homologous end-joining (NHEJ) in humans. DSBs cytotoxicity is largely exploited in anticancer therapy. Thus, NHEJ is an attractive target for strategies aimed at increasing the sensitivity of tumors to clastogenic anticancer treatments. However the high affinity of the XRCC4/Lig4 interaction and the extended protein-protein interface make drug screening on this target particularly challenging. Here, we conducted a pioneering study aimed at interfering with XRCC4/Lig4 assembly. By Molecular Dynamics simulation using the crystal structure of the complex, we first delineated the Lig4 clamp domain as a limited suitable target. Then, we performed in silico screening of ~95,000 filtered molecules on this Lig4 subdomain. Hits were evaluated by Differential Scanning Fluorimetry, Saturation Transfer Difference - NMR spectroscopy and interaction assays with purified recombinant proteins. In this way we identified the first molecule able to prevent Lig4 binding to XRCC4 in vitro. This compound has a unique tripartite interaction with the Lig4 clamp domain that suggests a starting chemotype for rational design of analogous molecules with improved affinity.

Efficient hit-finding approaches for histone methyltransferases: the key parameters.

PubMed

Ahrens, Thomas; Bergner, Andreas; Sheppard, David; Hafenbradl, Doris

2012-01-01

For many novel epigenetics targets the chemical ligand space and structural information were limited until recently and are still largely unknown for some targets. Hit-finding campaigns are therefore dependent on large and chemically diverse libraries. In the specific case of the histone methyltransferase G9a, the authors have been able to apply an efficient process of intelligent selection of compounds for primary screening, rather than screening the full diverse deck of 900 000 compounds to identify hit compounds. A number of different virtual screening methods have been applied for the compound selection, and the results have been analyzed in the context of their individual success rates. For the primary screening of 2112 compounds, a FlashPlate assay format and full-length histone H3.1 substrate were employed. Validation of hit compounds was performed using the orthogonal fluorescence lifetime technology. Rated by purity and IC(50) value, 18 compounds (0.9% of compound screening deck) were finally considered validated primary G9a hits. The hit-finding approach has led to novel chemotypes being identified, which can facilitate hit-to-lead projects. This study demonstrates the power of virtual screening technologies for novel, therapeutically relevant epigenetics protein targets.

Detailed Exploration around 4-Aminoquinolines Chemical Space to Navigate the Lysine Methyltransferase G9a and DNA Methyltransferase Biological Spaces.

PubMed

Rabal, Obdulia; Sánchez-Arias, Juan A; San José-Eneriz, Edurne; Agirre, Xabier; De Miguel, Irene; Garate, Leire; Miranda, Estibaliz; Sáez, Elena; Roa, Sergio; Martinez-Climent, Jose Angel; Liu, Yingying; Wu, Wei; Xu, Musheng; Prosper, Felipe; Oyarzabal, Julen

2018-06-11

Epigenetic regulators that exhibit aberrant enzymatic activities or expression profiles are potential therapeutic targets for cancers. Specifically, enzymes responsible for methylation at histone-3 lysine-9 (like G9a) and aberrant DNA hypermethylation (DNMTs) have been implicated in a number of cancers. Recently, molecules bearing a 4-aminoquinoline scaffold were reported as dual inhibitors of these targets and showed a significant in-vivo efficacy in animal models of hematological malignancies. Here, we report a detailed exploration around three growing vectors born by this chemotype. Exploring this chemical space led to the identification of features to navigate G9a and DNMT1 biological spaces; not only their corresponding exclusive areas, selective compounds, but also common spaces. Thus, we identified from selective G9a and first-in-class DNMT1 inhibitors, > 1 log unit between their IC50 values, with IC50 < 25nM (e.g. 43 and 26, respectively) to equipotent inhibitors with IC50 < 50nM for both targets (e.g. 13). Their ADME/Tox profiling and antiproliferative efficacies, versus some cancer cell lines, are also reported.

Discovery and Characterization of a Highly Potent and Selective Aminopyrazoline-Based in Vivo Probe (BAY-598) for the Protein Lysine Methyltransferase SMYD2.

PubMed

Eggert, Erik; Hillig, Roman C; Koehr, Silke; Stöckigt, Detlef; Weiske, Jörg; Barak, Naomi; Mowat, Jeffrey; Brumby, Thomas; Christ, Clara D; Ter Laak, Antonius; Lang, Tina; Fernandez-Montalvan, Amaury E; Badock, Volker; Weinmann, Hilmar; Hartung, Ingo V; Barsyte-Lovejoy, Dalia; Szewczyk, Magdalena; Kennedy, Steven; Li, Fengling; Vedadi, Masoud; Brown, Peter J; Santhakumar, Vijayaratnam; Arrowsmith, Cheryl H; Stellfeld, Timo; Stresemann, Carlo

2016-05-26

Protein lysine methyltransferases have recently emerged as a new target class for the development of inhibitors that modulate gene transcription or signaling pathways. SET and MYND domain containing protein 2 (SMYD2) is a catalytic SET domain containing methyltransferase reported to monomethylate lysine residues on histone and nonhistone proteins. Although several studies have uncovered an important role of SMYD2 in promoting cancer by protein methylation, the biology of SMYD2 is far from being fully understood. Utilization of highly potent and selective chemical probes for target validation has emerged as a concept which circumvents possible limitations of knockdown experiments and, in particular, could result in an improved exploration of drug targets with a complex underlying biology. Here, we report the development of a potent, selective, and cell-active, substrate-competitive inhibitor of SMYD2, which is the first reported inhibitor suitable for in vivo target validation studies in rodents.

Antimalarial activity and safety assessment of Flueggea virosa leaves and its major constituent with special emphasis on their mode of action.

PubMed

Singh, Shiv Vardan; Manhas, Ashan; Kumar, Yogesh; Mishra, Sonali; Shanker, Karuna; Khan, Feroz; Srivastava, Kumkum; Pal, Anirban

2017-05-01

A clinical emergency stands due to the appearance of drug resistant Plasmodium strains necessitate novel and effective antimalarial chemotypes, where plants seem as the prime option, especially after the discovery of quinine and artemisinin. The present study was aimed towards bioprospecting leaves of Flueggea virosa for its antimalarial efficacy and active principles. Crude hydro-ethanolic extract along with solvent derived fractions were tested in vitro against Plasmodium falciparum CQ sensitive (3D7) and resistant (K1) strains, where all the fractions exhibited potential activity (IC 50 values <10μg/mL) against both the strains. Interestingly, under in vivo conditions against P. berghei in Swiss mice, preferential chemo-suppression was recorded for crude hydro-ethanolic extract (77.38%) and ethyl acetate fraction (86.09%) at the dose of 500mg/kg body weight. Additionally, ethyl acetate fraction was found to be capable of normalizing the host altered pharmacological parameters and enhanced oxidative stress augmented during the infection. The bioactivity guided fractionation lead to the isolation of bergenin as a major and active constituent (IC 50, 8.07±2.05μM) of ethyl acetate fraction with the inhibition of heme polymerization pathway of malaria parasite being one of the possible chemotherapeutic target. Furthermore, bergenin exhibited a moderate antimalarial activity against P. berghei and also ameliorated parasite induced systemic inflammation in host (mice). Safe toxicity profile elucidated through in vitro cytotoxicity and in silico ADME/T predications evidently suggest that bergenin possess drug like properties. Hence, the present study validates the traditional usage of F. indica as an antimalarial remedy and also insists for further chemical modifications of bergenin to obtain more effective antimalarial chemotypes. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

A targeted IL-15 fusion protein with potent anti-tumor activity

PubMed Central

Chen, Siqi; Huang, Qiang; Liu, Jiayu; Xing, Jieyu; Zhang, Ning; Liu, Yawei; Wang, Zhong; Li, Qing

2015-01-01

IL-15 has been actively investigated for its potential in tumor immunotherapy. To enhance the anti-tumor activity of IL-15, the novel PFC-1 construct was designed, which comprises the following 3 parts: (1) IL-15Rα fused with IL-15 to enhance IL-15 activity, (2) an Fc fragment to increase protein half-life, and (3) an integrin-targeting RGD peptide to enhance tumor targeting. PFC-1 showed tumor cell targeting without compromising IL-15 activity. PFC-1 also had potent anti-tumor activities in xenograft models, suggesting the potential application of this multi-functional fusion protein in tumor therapy. PMID:26176990

Tuberculosis: a balanced diet of lipids and carbohydrates.

PubMed

Bhowruth, Veemal; Alderwick, Luke J; Brown, Alistair K; Bhatt, Apoorva; Besra, Gurdyal S

2008-08-01

In spite of effective antibiotics to treat TB (tuberculosis) since the early 1960s, we enter the new millennium with TB currently the leading cause of death from a single infectious agent, killing more than 3 million people worldwide each year. Thus an understanding of drug-resistance mechanisms, the immunobiology of cell wall components to elucidate host-pathogen interactions and the discovery of new drug targets are now required for the treatment of TB. Above the plasma membrane is a classical chemotype IV peptidoglycan to which is attached the macromolecular structure, mycolyl-arabinogalactan via a unique diglycosylphosphoryl bridge. The present review discusses the assembly of the mAGP (mycolyl-arabinogalactan-peptidoglycan) complex and the site of action of EMB (ethambutol), bringing forward a new era in TB research and focus for new drugs to combat multidrug-resistant TB.

Photochemical Approaches to Complex Chemotypes: Applications in Natural Product Synthesis

PubMed Central

2016-01-01

The use of photochemical transformations is a powerful strategy that allows for the formation of a high degree of molecular complexity from relatively simple building blocks in a single step. A central feature of all light-promoted transformations is the involvement of electronically excited states, generated upon absorption of photons. This produces transient reactive intermediates and significantly alters the reactivity of a chemical compound. The input of energy provided by light thus offers a means to produce strained and unique target compounds that cannot be assembled using thermal protocols. This review aims at highlighting photochemical transformations as a tool for rapidly accessing structurally and stereochemically diverse scaffolds. Synthetic designs based on photochemical transformations have the potential to afford complex polycyclic carbon skeletons with impressive efficiency, which are of high value in total synthesis. PMID:27120289

Effects of Elevated CO2 on the Swainsonine Chemotypes of Astragalus lentiginosus and Astragalus mollissimus.

PubMed

Cook, Daniel; Gardner, Dale R; Pfister, James A; Stonecipher, Clinton A; Robins, Joseph G; Morgan, Jack A

2017-03-01

Rapid changes in the Earth's atmosphere and climate associated with human activity can have significant impacts on agriculture including livestock production. CO 2 concentration has risen from the industrial revolution to the current time, and is expected to continue to rise. Climatic changes alter physiological processes, growth, and development in numerous plant species, potentially changing concentrations of plant secondary compounds. These physiological changes may influence plant population density, growth, fitness, and toxin concentrations and thus influence the risk of toxic plants to grazing livestock. Locoweeds, swainsonine-containing Astragalus species, are one group of plants that may be influenced by climate change. We evaluated how two different swainsonine-containing Astragalus species responded to elevated CO 2 concentrations. Measurements of biomass, crude protein, water soluble carbohydrates and swainsonine concentrations were measured in two chemotypes (positive and negative for swainsonine) of each species after growth at CO 2 levels near present day and at projected future concentrations. Biomass and water soluble carbohydrate concentrations responded positively while crude protein concentrations responded negatively to elevated CO 2 in the two species. Swainsonine concentrations were not strongly affected by elevated CO 2 in the two species. In the different chemotypes, biomass responded negatively and crude protein concentrations responded positively in the swainsonine-positive plants compared to the swainsonine-negative plants. Ultimately, changes in CO 2 and endophyte status will likely alter multiple physiological responses in toxic plants such as locoweed, but it is difficult to predict how these changes will impact plant herbivore interactions.

Identifying three ecological chemotypes of Xanthium strumarium glandular trichomes using a combined NMR and LC-MS method.

PubMed

Chen, Fangfang; Hao, Fuhua; Li, Changfu; Gou, Junbo; Lu, Dayan; Gong, Fujun; Tang, Huiru; Zhang, Yansheng

2013-01-01

Xanthanolides, as the sesquiterpene lactones, are reportedly the major components for the pharmacological properties of X. strumarium L. species. Phytochemical studies indicated that the glandular structures on the surface of plant tissues would form the primary sites for the accumulation of this class of the compounds. As the interface between plants and their natural enemies, glandular trichomes may vary with respect to which of their chemicals are sequestered against different herbivores in different ecologies. However, to date, no data are available on the chemical characterisation of X. strumarium glandular cells. In this study, the trichome secretions of the X. strumarium species originating from nineteen unique areas across eleven provinces in China, were analysed by HPLC, LC-ESI-MS and NMR. For the first time three distinct chemotypes of X. strumarium glandular trichomes were discovered along with the qualitative and quantitative evaluations of their presence of xanthanolides; these were designated glandular cell Types I, II, and III, respectively. The main xanthanolides in Type I cells were 8-epi-xanthatin and xanthumin while no xanthatin was detected. Xanthatin, 8-epi-xanthatin, and xanthumin dominated in Type II cells with comparable levels of each being present. For Type III cells, significantly higher concentrations of 8-epi-xanthatin or xanthinosin (relative to xanthatin) were detected with xanthinosin only being observed in this type. Further research will focus on understanding the ecological and molecular mechanism causing these chemotype differences in X. strumarium glandular structures.

Identifying Three Ecological Chemotypes of Xanthium strumarium Glandular Trichomes Using a Combined NMR and LC-MS Method

PubMed Central

Gou, Junbo; Lu, Dayan; Gong, Fujun; Tang, Huiru; Zhang, Yansheng

2013-01-01

Xanthanolides, as the sesquiterpene lactones, are reportedly the major components for the pharmacological properties of X. strumarium L. species. Phytochemical studies indicated that the glandular structures on the surface of plant tissues would form the primary sites for the accumulation of this class of the compounds. As the interface between plants and their natural enemies, glandular trichomes may vary with respect to which of their chemicals are sequestered against different herbivores in different ecologies. However, to date, no data are available on the chemical characterisation of X. strumarium glandular cells. In this study, the trichome secretions of the X. strumarium species originating from nineteen unique areas across eleven provinces in China, were analysed by HPLC, LC-ESI-MS and NMR. For the first time three distinct chemotypes of X. strumarium glandular trichomes were discovered along with the qualitative and quantitative evaluations of their presence of xanthanolides; these were designated glandular cell Types I, II, and III, respectively. The main xanthanolides in Type I cells were 8-epi-xanthatin and xanthumin while no xanthatin was detected. Xanthatin, 8-epi-xanthatin, and xanthumin dominated in Type II cells with comparable levels of each being present. For Type III cells, significantly higher concentrations of 8-epi-xanthatin or xanthinosin (relative to xanthatin) were detected with xanthinosin only being observed in this type. Further research will focus on understanding the ecological and molecular mechanism causing these chemotype differences in X. strumarium glandular structures. PMID:24098541

Variations in foliar monoterpenes across the range of jack pine reveal three widespread chemotypes: implications to host expansion of invasive mountain pine beetle.

PubMed

Taft, Spencer; Najar, Ahmed; Godbout, Julie; Bousquet, Jean; Erbilgin, Nadir

2015-01-01

The secondary compounds of pines (Pinus) can strongly affect the physiology, ecology and behaviors of the bark beetles (Coleoptera: Curculionidae, Scolytinae) that feed on sub-cortical tissues of hosts. Jack pine (Pinus banksiana) has a wide natural distribution range in North America (Canada and USA) and thus variations in its secondary compounds, particularly monoterpenes, could affect the host expansion of invasive mountain pine beetle (Dendroctonus ponderosae), which has recently expanded its range into the novel jack pine boreal forest. We investigated monoterpene composition of 601 jack pine trees from natural and provenance forest stands representing 63 populations from Alberta to the Atlantic coast. Throughout its range, jack pine exhibited three chemotypes characterized by high proportions of α-pinene, β-pinene, or limonene. The frequency with which the α-pinene and β-pinene chemotypes occurred at individual sites was correlated to climatic variables, such as continentality and mean annual precipitation, as were the individual α-pinene and β-pinene concentrations. However, other monoterpenes were generally not correlated to climatic variables or geographic distribution. Finally, while the enantiomeric ratios of β-pinene and limonene remained constant across jack pine's distribution, (-):(+)-α-pinene exhibited two separate trends, thereby delineating two α-pinene phenotypes, both of which occurred across jack pine's range. These significant variations in jack pine monoterpene composition may have cascading effects on the continued eastward spread and success of D. ponderosae in the Canadian boreal forest.

α-Linalool - a marker compound of forged/synthetic sweet basil (Ocimum basilicum L.) essential oils.

PubMed

Radulović, Niko S; Blagojević, Polina D; Miltojević, Ana B

2013-10-01

Ocimum basilicum L. (sweet basil) is known to occur as several chemotypes or cultivars that differ in their essential oil composition. The surprising discovery of 3,7-dimethylocta-1,7-dien-3-ol, the rare α isomer of the well-known monoterpene alcohol β-linalool (3,7-dimethylocta-1,6-dien-3-ol), in samples of Serbian basil oil provoked an investigation of the origin of α-linalool in these samples. Three scenarios were considered, namely (a) the existence of a new natural chemotype, (b) an artefactual formation during the isolation procedure and (c) the case of a synthetic/forged oil. Noteworthy amounts (15.1-16.9%) of pure α-linalool were isolated from a commercial sample of basil oil, and detailed spectral analyses (MS, IR, (1) H and (13) C NMR) unequivocally confirmed its identity. The analysis by GC and GC/MS of an additional 20 samples of different O. basilicum oils commercially available on the Serbian market or isolated from plant material cultivated in Serbia resulted in the identification of 149 compounds. The obtained compositional data were compared using multivariate statistical analysis to reveal the possible existence of a new basil chemotype. The results of the chemical and statistical analyses give more pro arguments for the synthetic/forged oil hypothesis and suggest that α-linalool could be used as a marker compound of such O. basilicum oils. © 2013 Society of Chemical Industry.

Inhibition of aldose reductase activity by Cannabis sativa chemotypes extracts with high content of cannabidiol or cannabigerol.

PubMed

Smeriglio, Antonella; Giofrè, Salvatore V; Galati, Enza M; Monforte, Maria T; Cicero, Nicola; D'Angelo, Valeria; Grassi, Gianpaolo; Circosta, Clara

2018-02-07

Aldose reductase (ALR2) is a key enzyme involved in diabetic complications and the search for new aldose reductase inhibitors (ARIs) is currently very important. The synthetic ARIs are often associated with deleterious side effects and medicinal and edible plants, containing compounds with aldose reductase inhibitory activity, could be useful for prevention and therapy of diabetic complications. Non-psychotropic phytocannabinoids exert multiple pharmacological effects with therapeutic potential in many diseases such as inflammation, cancer, diabetes. Here, we have investigated the inhibitory effects of extracts and their fractions from two Cannabis sativa L. chemotypes with high content of cannabidiol (CBD)/cannabidiolic acid (CBDA) and cannabigerol (CBG)/cannabigerolic acid (CBGA), respectively, on human recombinant and pig kidney aldose reductase activity in vitro. A molecular docking study was performed to evaluate the interaction of these cannabinoids with the active site of ALR2 compared to known ARIs. The extracts showed significant dose-dependent aldose reductase inhibitory activity (>70%) and higher than fractions. The inhibitory activity of the fractions was greater for acidic cannabinoid-rich fractions. Comparative molecular docking results have shown a higher stability of the ALR2-cannabinoid acids complex than the other inhibitors. The extracts of Cannabis with high content of non-psychotropic cannabinoids CBD/CBDA or CBG/CBGA significantly inhibit aldose reductase activity. These results may have some relevance for the possible use of C. sativa chemotypes based preparations as aldose reductase inhibitors. Copyright © 2018 Elsevier B.V. All rights reserved.

Antibody Drug Conjugates: Application of Quantitative Pharmacology in Modality Design and Target Selection.

PubMed

Sadekar, S; Figueroa, I; Tabrizi, M

2015-07-01

Antibody drug conjugates (ADCs) are a multi-component modality comprising of an antibody targeting a cell-specific antigen, a potent drug/payload, and a linker that can be processed within cellular compartments to release payload upon internalization. Numerous ADCs are being evaluated in both research and clinical settings within the academic and pharmaceutical industry due to their ability to selectively deliver potent payloads. Hence, there is a clear need to incorporate quantitative approaches during early stages of drug development for effective modality design and target selection. In this review, we describe a quantitative approach and framework for evaluation of the interplay between drug- and systems-dependent properties (i.e., target expression, density, localization, turnover, and affinity) in order to deliver a sufficient amount of a potent payload into the relevant target cells. As discussed, theoretical approaches with particular considerations given to various key properties for the target and modality suggest that delivery of the payload into particular effect cells to be more sensitive to antigen concentrations for targets with slow turnover rates as compared to those with faster internalization rates. Further assessments also suggest that increasing doses beyond the threshold of the target capacity (a function of target internalization and expression) may not impact the maximum amount of payload delivered to the intended effect cells. This article will explore the important application of quantitative sciences in selection of the target and design of ADC modalities.

Specific Btk inhibition suppresses B cell- and myeloid cell-mediated arthritis.

PubMed

Di Paolo, Julie A; Huang, Tao; Balazs, Mercedesz; Barbosa, James; Barck, Kai H; Bravo, Brandon J; Carano, Richard A D; Darrow, James; Davies, Douglas R; DeForge, Laura E; Diehl, Lauri; Ferrando, Ronald; Gallion, Steven L; Giannetti, Anthony M; Gribling, Peter; Hurez, Vincent; Hymowitz, Sarah G; Jones, Randall; Kropf, Jeffrey E; Lee, Wyne P; Maciejewski, Patricia M; Mitchell, Scott A; Rong, Hong; Staker, Bart L; Whitney, J Andrew; Yeh, Sherry; Young, Wendy B; Yu, Christine; Zhang, Juan; Reif, Karin; Currie, Kevin S

2011-01-01

Bruton's tyrosine kinase (Btk) is a therapeutic target for rheumatoid arthritis, but the cellular and molecular mechanisms by which Btk mediates inflammation are poorly understood. Here we describe the discovery of CGI1746, a small-molecule Btk inhibitor chemotype with a new binding mode that stabilizes an inactive nonphosphorylated enzyme conformation. CGI1746 has exquisite selectivity for Btk and inhibits both auto- and transphosphorylation steps necessary for enzyme activation. Using CGI1746, we demonstrate that Btk regulates inflammatory arthritis by two distinct mechanisms. CGI1746 blocks B cell receptor-dependent B cell proliferation and in prophylactic regimens reduces autoantibody levels in collagen-induced arthritis. In macrophages, Btk inhibition abolishes FcγRIII-induced TNFα, IL-1β and IL-6 production. Accordingly, in myeloid- and FcγR-dependent autoantibody-induced arthritis, CGI1746 decreases cytokine levels within joints and ameliorates disease. These results provide new understanding of the function of Btk in both B cell- or myeloid cell-driven disease processes and provide a compelling rationale for targeting Btk in rheumatoid arthritis.

Specific Btk inhibition suppresses B cell- and myeloid cell-mediated arthritis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Paolo, Julie A; Huang, Tao; Balazs, Mercedesz

Bruton's tyrosine kinase (Btk) is a therapeutic target for rheumatoid arthritis, but the cellular and molecular mechanisms by which Btk mediates inflammation are poorly understood. Here we describe the discovery of CGI1746, a small-molecule Btk inhibitor chemotype with a new binding mode that stabilizes an inactive nonphosphorylated enzyme conformation. CGI1746 has exquisite selectivity for Btk and inhibits both auto- and transphosphorylation steps necessary for enzyme activation. Using CGI1746, we demonstrate that Btk regulates inflammatory arthritis by two distinct mechanisms. CGI1746 blocks B cell receptor–dependent B cell proliferation and in prophylactic regimens reduces autoantibody levels in collagen-induced arthritis. In macrophages, Btkmore » inhibition abolishes FcγRIII-induced TNFα, IL-1β and IL-6 production. Accordingly, in myeloid- and FcγR-dependent autoantibody-induced arthritis, CGI1746 decreases cytokine levels within joints and ameliorates disease. These results provide new understanding of the function of Btk in both B cell– or myeloid cell–driven disease processes and provide a compelling rationale for targeting Btk in rheumatoid arthritis.« less

Specific Btk inhibition suppresses B cell- and myeloid cell-mediated arthritis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Paolo, Julie A.; Huang, Tao; Balazs, Mercedesz

Bruton's tyrosine kinase (Btk) is a therapeutic target for rheumatoid arthritis, but the cellular and molecular mechanisms by which Btk mediates inflammation are poorly understood. Here we describe the discovery of CGI1746, a small-molecule Btk inhibitor chemotype with a new binding mode that stabilizes an inactive nonphosphorylated enzyme conformation. CGI1746 has exquisite selectivity for Btk and inhibits both auto- and transphosphorylation steps necessary for enzyme activation. Using CGI1746, we demonstrate that Btk regulates inflammatory arthritis by two distinct mechanisms. CGI1746 blocks B cell receptor-dependent B cell proliferation and in prophylactic regimens reduces autoantibody levels in collagen-induced arthritis. In macrophages, Btkmore » inhibition abolishes Fc{gamma}RIII-induced TNF{alpha}, IL-1{beta} and IL-6 production. Accordingly, in myeloid- and Fc{gamma}R-dependent autoantibody-induced arthritis, CGI1746 decreases cytokine levels within joints and ameliorates disease. These results provide new understanding of the function of Btk in both B cell- or myeloid cell-driven disease processes and provide a compelling rationale for targeting Btk in rheumatoid arthritis.« less

Cancer and Stroma-Targeted Immunotherapy with a Genetically Modified DC Vaccine

DTIC Science & Technology

2011-05-01

targeting the tumor stroma in addition to breast cancer cells may produce the desired increase in antitumor activity of DC vaccines for breast cancer...vaccination inhibits 4T1-neu progression. We investigated whether DC-shA20-FAP- HER2 may induce more potent anti- stroma and anti-tumor immunity with the...the immunosuppressive tumor microenviroment resulting in potent antitumor activity. Zhu W, Zhou X, Rollins L , Rooney CM, Gottschalk S, Song XT

Discovery of a new method for potent drug development using power function of stoichiometry ofhomomeric biocomplexes or biological nanomotors

PubMed Central

Pi, Fengmei; Vieweger, Mario; Zhao, Zhengyi; Wang, Shaoying; Guo, Peixuan

2015-01-01

Introduction Multidrug resistance and the appearance of incurable diseases inspire the quest for potent therapeutics. Areas Covered We review a new methodology in designing potent drugs by targeting multi-subunit homomeric biological motors, machines, or complexes with Z>1 and K=1, where Z is the stoichiometry of the target, and K is the number of drugged subunits required to block the function of the complex. The condition is similar to a series, electrical circuit of Christmas decorations; failure of one light bulb causes the entire lighting system to lose power. In most multisubunit, homomeric biological systems, a sequential coordination or cooperative action mechanism is utilized, thus K equals 1. Drug inhibition depends on the ratio of drugged to nondrugged complexes. When K=1, and Z>1, the inhibition effect follows a power law with respect to Z, leading to enhanced drug potency. The hypothesis that the potency of drug inhibition depends on the stoichiometry of the targeted biological complexes was recently quantified by Yang-Hui's Triangle (or binomial distribution), and proved using a highly sensitive in vitro phi29 viral DNA packaging system. Examples of targeting homomeric bio-complexes with high stoichiometry for potent drug discovery are discussed. Expert Opinion Biomotors with multiple subunits are widespread in viruses, bacteria, and cells, making this approach generally applicable in the development of inhibition drugs with high efficiency. PMID:26307193

Targeting cancer by binding iron: Dissecting cellular signaling pathways

PubMed Central

Lui, Goldie Y.L.; Kovacevic, Zaklina; Richardson, Vera; Merlot, Angelica M.; Kalinowski, Danuta S.; Richardson, Des R.

2015-01-01

Newer and more potent therapies are urgently needed to effectively treat advanced cancers that have developed resistance and metastasized. One such strategy is to target cancer cell iron metabolism, which is altered compared to normal cells and may facilitate their rapid proliferation. This is supported by studies reporting the anti-neoplastic activities of the clinically available iron chelators, desferrioxamine and deferasirox. More recently, ligands of the di-2-pyridylketone thiosemicarbazone (DpT) class have demonstrated potent and selective anti-proliferative activity across multiple cancer-types in vivo, fueling studies aimed at dissecting their molecular mechanisms of action. In the past five years alone, significant advances have been made in understanding how chelators not only modulate cellular iron metabolism, but also multiple signaling pathways implicated in tumor progression and metastasis. Herein, we discuss recent research on the targeting of iron in cancer cells, with a focus on the novel and potent DpT ligands. Several key studies have revealed that iron chelation can target the AKT, ERK, JNK, p38, STAT3, TGF-β, Wnt and autophagic pathways to subsequently inhibit cellular proliferation, the epithelial-mesenchymal transition (EMT) and metastasis. These developments emphasize that these novel therapies could be utilized clinically to effectively target cancer. PMID:26125440

Phenylthiazole Antibacterial Agents Targeting Cell Wall Synthesis Exhibit Potent Activity in Vitro and in Vivo against Vancomycin-Resistant Enterococci.

PubMed

Mohammad, Haroon; Younis, Waleed; Chen, Lu; Peters, Christine E; Pogliano, Joe; Pogliano, Kit; Cooper, Bruce; Zhang, Jianan; Mayhoub, Abdelrahman; Oldfield, Eric; Cushman, Mark; Seleem, Mohamed N

2017-03-23

The emergence of antibiotic-resistant bacterial species, such as vancomycin-resistant enterococci (VRE), necessitates the development of new antimicrobials. Here, we investigate the spectrum of antibacterial activity of three phenylthiazole-substituted aminoguanidines. These compounds possess potent activity against VRE, inhibiting growth of clinical isolates at concentrations as low as 0.5 μg/mL. The compounds exerted a rapid bactericidal effect, targeting cell wall synthesis. Transposon mutagenesis suggested three possible targets: YubA, YubB (undecaprenyl diphosphate phosphatase (UPPP)), and YubD. Both UPPP as well as undecaprenyl diphosphate synthase were inhibited by compound 1. YubA and YubD are annotated as transporters and may also be targets because 1 collapsed the proton motive force in membrane vesicles. Using Caenorhabditis elegans, we demonstrate that two compounds (1, 3, at 20 μg/mL) retain potent activity in vivo, significantly reducing the burden of VRE in infected worms. Taken altogether, the results indicate that compounds 1 and 3 warrant further investigation as novel antibacterial agents against drug-resistant enterococci.

Native State Mass Spectrometry, Surface Plasmon Resonance, and X-ray Crystallography Correlate Strongly as a Fragment Screening Combination.

PubMed

Woods, Lucy A; Dolezal, Olan; Ren, Bin; Ryan, John H; Peat, Thomas S; Poulsen, Sally-Ann

2016-03-10

Fragment-based drug discovery (FBDD) is contingent on the development of analytical methods to identify weak protein-fragment noncovalent interactions. Herein we have combined an underutilized fragment screening method, native state mass spectrometry, together with two proven and popular fragment screening methods, surface plasmon resonance and X-ray crystallography, in a fragment screening campaign against human carbonic anhydrase II (CA II). In an initial fragment screen against a 720-member fragment library (the "CSIRO Fragment Library") seven CA II binding fragments, including a selection of nonclassical CA II binding chemotypes, were identified. A further 70 compounds that comprised the initial hit chemotypes were subsequently sourced from the full CSIRO compound collection and screened. The fragment results were extremely well correlated across the three methods. Our findings demonstrate that there is a tremendous opportunity to apply native state mass spectrometry as a complementary fragment screening method to accelerate drug discovery.

Chemotypic Characterization and Biological Activity of Rosmarinus officinalis.

PubMed

Satyal, Prabodh; Jones, Tyler H; Lopez, Elizabeth M; McFeeters, Robert L; Ali, Nasser A Awadh; Mansi, Iman; Al-Kaf, Ali G; Setzer, William N

2017-03-05

Rosemary ( Rosmarinus officinalis L.) is a popular herb in cooking, traditional healing, and aromatherapy. The essential oils of R. officinalis were obtained from plants growing in Victoria (Australia), Alabama (USA), Western Cape (South Africa), Kenya, Nepal, and Yemen. Chemical compositions of the rosemary oils were analyzed by gas chromatography-mass spectrometry as well as chiral gas chromatography. The oils were dominated by (+)-α-pinene (13.5%-37.7%), 1,8-cineole (16.1%-29.3%), (+)-verbenone (0.8%-16.9%), (-)-borneol (2.1%-6.9%), (-)-camphor (0.7%-7.0%), and racemic limonene (1.6%-4.4%). Hierarchical cluster analysis, based on the compositions of these essential oils in addition to 72 compositions reported in the literature, revealed at least five different chemotypes of rosemary oil. Antifungal, cytotoxicity, xanthine oxidase inhibitory, and tyrosinase inhibitory activity screenings were carried out, but showed only marginal activities.

Phytotoxicity and Cytotoxicity of Essential Oil from Leaves of Plectranthus amboinicus, Carvacrol, and Thymol in Plant Bioassays.

PubMed

Pinheiro, Patrícia Fontes; Costa, Adilson Vidal; Alves, Thammyres de Assis; Galter, Iasmini Nicoli; Pinheiro, Carlos Alexandre; Pereira, Alexandre Fontes; Oliveira, Carlos Magno Ramos; Fontes, Milene Miranda Praça

2015-10-21

The essential oil of Plectranthus amboinicus and its chemotypes, carvacrol and thymol, were evaluated on the germination and root and aerial growth of Lactuca sativa and Sorghum bicolor and in acting on the cell cycle of meristematic root cells of L. sativa. The main component found in the oil by analysis in gas chromatography-mass spectrometry and gas chromatography flame ionization detection was carvacrol (88.61% in area). At a concentration of 0.120% (w v(-1)), the oil and its chemotypes retarded or inhibited the germination and decreased root and aerial growth in monocot and dicot species used in the bioassays. In addition, all substances caused changes in the cell cycle of the meristematic cells of L. sativa, with chromosomal alterations occurring from the 0.015% (w v(-1)) concentration. The essential oil of P. amboinicus, carvacrol, and thymol have potential for use as bioherbicides.

Rapid evaluation and quantitative analysis of thyme, origano and chamomile essential oils by ATR-IR and NIR spectroscopy

NASA Astrophysics Data System (ADS)

Schulz, Hartwig; Quilitzsch, Rolf; Krüger, Hans

2003-12-01

The essential oils obtained from various chemotypes of thyme, origano and chamomile species were studied by ATR/FT-IR as well as NIR spectroscopy. Application of multivariate statistics (PCA, PLS) in conjunction with analytical reference data leads to very good IR and NIR calibration results. For the main essential oil components (e.g. carvacrol, thymol, γ-terpinene, α-bisabolol and β-farnesene) standard errors are in the range of the applied GC reference method. In most cases the multiple coefficients of determination ( R2) are >0.97. Using the IR fingerprint region (900-1400 cm -1) a qualitative discrimination of the individual chemotypes is possible already by visual judgement without to apply any chemometric algorithms.The described rapid and non-destructive methods can be applied in industry to control very easily purifying, blending and redistillation processes of the mentioned essential oils.

Chemotypic Characterization and Biological Activity of Rosmarinus officinalis

PubMed Central

Satyal, Prabodh; Jones, Tyler H.; Lopez, Elizabeth M.; McFeeters, Robert L.; Ali, Nasser A. Awadh; Mansi, Iman; Al-kaf, Ali G.; Setzer, William N.

2017-01-01

Rosemary (Rosmarinus officinalis L.) is a popular herb in cooking, traditional healing, and aromatherapy. The essential oils of R. officinalis were obtained from plants growing in Victoria (Australia), Alabama (USA), Western Cape (South Africa), Kenya, Nepal, and Yemen. Chemical compositions of the rosemary oils were analyzed by gas chromatography-mass spectrometry as well as chiral gas chromatography. The oils were dominated by (+)-α-pinene (13.5%–37.7%), 1,8-cineole (16.1%–29.3%), (+)-verbenone (0.8%–16.9%), (−)-borneol (2.1%–6.9%), (−)-camphor (0.7%–7.0%), and racemic limonene (1.6%–4.4%). Hierarchical cluster analysis, based on the compositions of these essential oils in addition to 72 compositions reported in the literature, revealed at least five different chemotypes of rosemary oil. Antifungal, cytotoxicity, xanthine oxidase inhibitory, and tyrosinase inhibitory activity screenings were carried out, but showed only marginal activities. PMID:28273883

A Systematic Evaluation of Analogs for the Read-across ...

EPA Pesticide Factsheets

Read-across is a data gap filling technique widely used within category and analog approaches to predict a biological property for a target data-poor chemical using known information from similar (source analog) chemical(s). Potential source analogs are typically identified based on structural similarity. Although much guidance has been published for read-across, practical guiding principles for the identification and evaluation of the scientific validity of source analogs, which is a critical step in deriving a robust read-across prediction, remains largely lacking.This case study explores the extent to which 3 structure descriptor sets (Pubchem, Chemotyper and MoSS) and their combinations are able to identify valid analogs for reading across Estrogen Receptor (ER) activity for a specific class of chemicals: hindered phenols. For each target chemical, two sets of analogs (hindered and non-hindered phenols) were selected using each descriptor set with two cut-offs: (1). Minimum Tanimoto similarity (range 0.1 - 0.9), and (2). Closest N analogs (range 1 - 10). Each target-analog pair was then evaluated for its agreement with measured ER binding and agonism. Subsequently, the analogs were filtered using physchem properties (LogKow & Molecular Volume) and the resultant agreement between each target-analog pair was evaluated. The data set comprised 462 hindered phenols and 296 non-hindered phenols. The results demonstrate that: (1). The concordance in ER activity r

A Systematic Evaluation of Analogs and Automated Read ...

EPA Pesticide Factsheets

Read-across is a data gap filling technique widely used within category and analog approaches to predict a biological property for a data-poor (target) chemical using known information from similar (source analog) chemical(s). Potential source analogs are typically identified based on structural similarity. Although much guidance has been published for read-across, practical principles for the identification and evaluation of the scientific validity of source analogs remains lacking. This case study explores how well 3 structure descriptor sets (Pubchem, Chemotyper and MoSS) are able to identify analogs for read-across and predict Estrogen Receptor (ER) binding activity for a specific class of chemicals: hindered phenols. For each target chemical, analogs were selected using each descriptor set with two cut-offs: (1) Minimum Tanimoto similarity (range 0.1 - 0.9), and (2) Closest N analogs (range 1 - 10). Each target-analog pair was then evaluated for its agreement with measured ER binding and agonism. The analogs were subsequently filtered using: (1) physchem properties (LogKow & Molecular Volume), and (2) number of literature sources as a marker for the quality of the experimental data. A majority vote prediction was made for each target phenol by reading-across from the closest N analogs. The data set comprised 462 hindered phenols and 257 non-hindered phenols. The results demonstrate that: (1) The concordance in ER activity rises with increasing similarity,

Laboratory and field measurements of enantiomeric monoterpene emissions as a function of chemotype, light and temperature

NASA Astrophysics Data System (ADS)

Song, W.; Staudt, M.; Bourgeois, I.; Williams, J.

2013-10-01

Plants emit significant amounts of monoterpenes into the Earth's atmosphere where they react rapidly to form a multitude of gas phase species and particles. Many monoterpenes exist in mirror images forms or enantiomers. In this study the enantiomeric monoterpene profile for several representative plants (Quercus ilex L., Rosmarinus officinalis L., and Pinus halepensis Mill.) was investigated as a function of chemotype, light and temperature both in the laboratory and in the field. Analysis of enantiomeric monoterpenes from 19 Quercus ilex individuals from Southern France and Spain revealed four regiospecific chemotypes (genetically fixed emission patterns). In agreement with previous work, only Quercus ilex emissions increased strongly with light. However, for all three plant species no consistent enantiomeric variation was observed as a function of light, and the enantiomeric ratio of α-pinene was found vary by less than 20% from 100 and 1000 μmol m-2 s-1 PAR. The rate of monoterpene emission increased with temperature from all three plant species, but little variation in the enantiomeric distribution of α-pinene was observed with temperature. There was more enantiomeric variability between individuals of the same species than could be induced by either light or temperature. Field measurements of α-pinene enantiomer mixing ratios in the air taken at a Quercus ilex forest in Southern France, and several other previously reported field enantiomeric ratio diel cycle profiles are compared. All show smoothly varying diel cycles (some positive and some negative) even over changing wind directions. This is surprising in comparison with variations of enantiomeric emission patterns shown by individuals of the same species.

A Generalizable Platform for Interrogating Target- and Signal-Specific Consequences of Electrophilic Modifications in Redox-Dependent Cell Signaling

PubMed Central

Lin, Hong-Yu; Haegele, Joseph A.; Disare, Michael T.; Lin, Qishan; Aye, Yimon

2015-01-01

Despite the known propensity of small-molecule electrophiles to react with numerous cysteine-active proteins, biological actions of individual signal inducers have emerged to be chemotype-specific. To pinpoint and quantify the impacts of modifying one target out of the whole proteome, we develop a target-protein-personalized “electrophile toolbox” with which specific intracellular targets can be selectively modified at a precise time by specific reactive signals. This general methodology—T-REX (targetable reactive electrophiles & oxidants)—is established by: (1) constructing a platform that can deliver a range of electronic and sterically different bioactive lipid-derived signaling electrophiles to specific proteins in cells; (2) probing the kinetics of targeted delivery concept which revealed that targeting efficiency in cells is largely driven by initial on-rate of alkylation; and (3) evaluating the consequences of protein-target- and small-molecule-signal-specific modifications on the strength of downstream signaling. These data show that T-REX allows quantitative interrogations into the extent to which the Nrf2 transcription factor-dependent antioxidant response element (ARE) signaling is activated by selective electrophilic modifications on Keap1 protein—one of several redox-sensitive regulators of the Nrf2–ARE axis. The results document Keap1 as a promiscuous electrophile-responsive sensor able to respond with similar efficiencies to discrete electrophilic signals, promoting comparable strength of Nrf2–ARE induction. T-REX is also able to elicit cell activation in cases in which whole-cell electrophile flooding fails to stimulate ARE induction prior to causing cytotoxicity. The platform presents a previously unavailable opportunity to elucidate the functional consequences of small-molecule-signal- and protein-target-specific electrophilic modifications in an otherwise unaffected cellular background. PMID:25909755

A generalizable platform for interrogating target- and signal-specific consequences of electrophilic modifications in redox-dependent cell signaling.

PubMed

Lin, Hong-Yu; Haegele, Joseph A; Disare, Michael T; Lin, Qishan; Aye, Yimon

2015-05-20

Despite the known propensity of small-molecule electrophiles to react with numerous cysteine-active proteins, biological actions of individual signal inducers have emerged to be chemotype-specific. To pinpoint and quantify the impacts of modifying one target out of the whole proteome, we develop a target-protein-personalized "electrophile toolbox" with which specific intracellular targets can be selectively modified at a precise time by specific reactive signals. This general methodology, T-REX (targetable reactive electrophiles and oxidants), is established by (1) constructing a platform that can deliver a range of electronic and sterically different bioactive lipid-derived signaling electrophiles to specific proteins in cells; (2) probing the kinetics of targeted delivery concept, which revealed that targeting efficiency in cells is largely driven by initial on-rate of alkylation; and (3) evaluating the consequences of protein-target- and small-molecule-signal-specific modifications on the strength of downstream signaling. These data show that T-REX allows quantitative interrogations into the extent to which the Nrf2 transcription factor-dependent antioxidant response element (ARE) signaling is activated by selective electrophilic modifications on Keap1 protein, one of several redox-sensitive regulators of the Nrf2-ARE axis. The results document Keap1 as a promiscuous electrophile-responsive sensor able to respond with similar efficiencies to discrete electrophilic signals, promoting comparable strength of Nrf2-ARE induction. T-REX is also able to elicit cell activation in cases in which whole-cell electrophile flooding fails to stimulate ARE induction prior to causing cytotoxicity. The platform presents a previously unavailable opportunity to elucidate the functional consequences of small-molecule-signal- and protein-target-specific electrophilic modifications in an otherwise unaffected cellular background.

Leucine-rich repeat kinase 2 inhibitors: a review of recent patents (2011 - 2013).

PubMed

Kethiri, Raghava R; Bakthavatchalam, Rajagopal

2014-07-01

Leucine-rich repeat kinase 2 (LRRK2) is a large (2527 residues) complex multi-domain protein that has GTPase and kinase domains. Autosomal dominant missense mutations in LRRK2 have been found in individuals with Parkinson's disease (PD) and are considered responsible for 1% of all cases of PD. Among the mutations confirmed to contribute to PD pathogenicity, G2019S is the most common cause of PD and it increases the kinase activity of LRRK2 by around threefold. LRRK2 has received considerable attention as a therapeutic target for PD, and LRRK2 inhibitors may help prevent and/or treat the disease. LRRK2 inhibitors are being investigated by various industrial and academic institutions. The present review covers patents literature on small-molecule LRRK2 inhibitors patented between 2011 and 2013. Currently, wild-type and mutant LRRK2 are being examined as therapeutic targets for PD. In testimony to the significance of these novel targets, over 20 patent applications related to LRRK2 have been filed in the last 3 years. Several distinct chemotypes have been reported to be LRRK2 inhibitors with very good potency. These compounds are being used to elucidate the physiological and pathophysiological functions of LRRK2, and some may even emerge as therapeutics for PD.

Progressing the global antimalarial portfolio: finding drugs which target multiple Plasmodium life stages.

PubMed

Smith, Paul W; Diagana, Thierry T; Yeung, Bryan K S

2014-01-01

The number of novel antimalarial candidates entering preclinical development has seen an increase over the last several years. Most of these drug candidates were originally identified as hits coming from screening large chemical libraries specifically targeting the asexual blood stages of Plasmodium falciparum. Indeed, a large proportion of the current antimalarial arsenal has mainly targeted the asexual blood stage which is responsible for clinical symptoms of the disease. However, as part of the eradication agenda and to address resistance, any next-generation antimalarial should have additional activity on at least one other parasite life stage, i.e. gametocytocidal and/or tissue schizonticidal activity. We have applied this approach by screening compounds with intrinsic activity on asexual blood stages in assays against sexual and liver stages and identified two new antimalarial chemotypes with activity on multiple parasite life stages. This strategy can be expanded to identify other chemical classes of molecules with similar activity profiles for the next generation antimalarials. The following review summarizes the discovery of the spiroindolones and imidazolopiperazine classes of antimalarials developed by the NGBS consortium (Novartis Institute for Tropical Diseases, Genomic Institute of the Novartis Research Foundation, Biomedical Primate Research Center, and the Swiss Tropical and Public Health Institute) currently in clinical trials.

KRAS G12C Drug Development: Discrimination between Switch II Pocket Configurations Using Hydrogen/Deuterium-Exchange Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Jia; Harrison, Rane A.; Li, Lianbo

KRAS G12C, the most common RAS mutation found in non-small-cell lung cancer, has been the subject of multiple recent covalent small-molecule inhibitor campaigns including efforts directed at the guanine nucleotide pocket and separate work focused on an inducible pocket adjacent to the switch motifs. Multiple conformations of switch II have been observed, suggesting that switch II pocket (SIIP) binders may be capable of engaging a range of KRAS conformations. Here we report the use of hydrogen/deuterium-exchange mass spectrometry (HDX MS) to discriminate between conformations of switch II induced by two chemical classes of SIIP binders. We investigated the structural basismore » for differences in HDX MS using X-ray crystallography and discovered a new SIIP configuration in response to binding of a quinazoline chemotype. These results have implications for structure-guided drug design targeting the RAS SIIP.« less

SHOP: scaffold HOPping by GRID-based similarity searches.

PubMed

Bergmann, Rikke; Linusson, Anna; Zamora, Ismael

2007-05-31

A new GRID-based method for scaffold hopping (SHOP) is presented. In a fully automatic manner, scaffolds were identified in a database based on three types of 3D-descriptors. SHOP's ability to recover scaffolds was assessed and validated by searching a database spiked with fragments of known ligands of three different protein targets relevant for drug discovery using a rational approach based on statistical experimental design. Five out of eight and seven out of eight thrombin scaffolds and all seven HIV protease scaffolds were recovered within the top 10 and 31 out of 31 neuraminidase scaffolds were in the 31 top-ranked scaffolds. SHOP also identified new scaffolds with substantially different chemotypes from the queries. Docking analysis indicated that the new scaffolds would have similar binding modes to those of the respective query scaffolds observed in X-ray structures. The databases contained scaffolds from published combinatorial libraries to ensure that identified scaffolds could be feasibly synthesized.

Chemodiversity of a Scots pine stand and implications for terpene air concentrations

NASA Astrophysics Data System (ADS)

Bäck, J.; Aalto, J.; Henriksson, M.; Hakola, H.; He, Q.; Boy, M.

2012-02-01

Atmospheric chemistry in background areas is strongly influenced by natural vegetation. Coniferous forests are known to produce large quantities of volatile vapors, especially terpenes. These compounds are reactive in the atmosphere, and contribute to the formation and growth of atmospheric new particles. Our aim was to analyze the variability of mono- and sesquiterpene emissions between Scots pine trees, in order to clarify the potential errors caused by using emission data obtained from only a few trees in atmospheric chemistry models. We also aimed at testing if stand history and seed origin has an influence on the chemotypic diversity. The inherited, chemotypic variability in mono- and sesquiterpene emission was studied in a seemingly homogeneous 48 yr-old stand in Southern Finland, where two areas differing in their stand regeneration history could be distinguished. Sampling was conducted in August 2009. Terpene concentrations in the air had been measured at the same site for seven years prior to branch sampling for chemotypes. Two main compounds, α-pinene and Δ3-carene formed together 40-97% of the monoterpene proportions in both the branch emissions and in the air concentrations. The data showed a bimodal distribution in emission composition, in particular in Δ3-carene emission within the studied population. 10% of the trees emitted mainly α-pinene and no Δ3-carene at all, whereas 20% of the trees where characterized as high Δ3-carene emitters (Δ3-carene forming >80% of total emitted monoterpene spectrum). An intermediate group of trees emitted equal amounts of both α-pinene and Δ3-carene. The emission pattern of trees at the area established using seeding as the artificial regeneration method differed from the naturally regenerated or planted trees, being mainly high Δ3-carene emitters. Some differences were also seen in e.g. camphene and limonene emissions between chemotypes, but sesquiterpene emissions did not differ significantly between trees. The atmospheric concentrations at the site were found to reflect the species and/or chemodiversity rather than the emissions measured from any single tree, and were strongly dominated by α-pinene. We also tested the effect of chemodiversity on modeled monoterpene concentrations at the site and found out that since it significantly influences the distributions and hence the chemical reactions in the atmosphere, it should be taken into account in atmospheric modeling.

Chemodiversity in terpene emissions at a boreal Scots pine stand

NASA Astrophysics Data System (ADS)

Bäck, J.; Aalto, J.; Henriksson, M.; Hakola, H.; He, Q.; Boy, M.

2011-10-01

Atmospheric chemistry in background areas is strongly influenced by natural vegetation. Coniferous forests are known to produce large quantities of volatile vapors, especially terpenes to the surrounding air. These compounds are reactive in the atmosphere, and contribute to the formation and growth of atmospheric new particles. Our aim was to analyze the variability of mono- and sesquiterpene emissions between Scots pine trees, in order to clarify the potential errors caused by using emission data obtained from only a few trees in atmospheric chemistry models. We also aimed at testing if stand history and seed origin has an influence on the chemotypic diversity. The inherited, chemotypic variability in mono- and sesquiterpene emission was studied in a seemingly homogeneous 47-yr-old stand in Southern Finland, where two areas differing in their stand regeneration history could be distinguished. Sampling was conducted in August 2009. Terpene concentrations in the air had been measured at the same site for seven years prior to branch sampling for chemotypes. Two main compounds, α-pinene and Δ3-carene formed together 40-97% of the monoterpene proportions in both the branch emissions and in the air concentrations. The data showed a bimodal distribution in emission composition, in particular in Δ3-carene emission within the studied population. 10% of the trees emitted mainly α-pinene and no Δ3-carene at all, whereas 20% of the trees where characterized as high Δ3-carene emitters (Δ3-carene forming >80% of total emitted monoterpene spectrum). An intermediate group of trees emitted equal amounts of both α-pinene and Δ3-carene. The emission pattern of trees at the area established using seeding as the artificial regeneration method differed from the naturally regenerated or planted trees, being mainly high Δ3-carene emitters. Some differences were also seen in e.g. camphene and limonene emissions between chemotypes, but sesquiterpene emissions did not differ significantly between trees. The atmospheric concentrations at the site were found to reflect the species and/or chemodiversity rather than the emissions measured from any single tree, and were strongly dominated by α-pinene. We also tested the effect of chemodiversity on modeled monoterpene concentrations at the site and found out that since it significantly influences the distributions and hence the chemical reactions in the atmosphere, it should be taken into account in atmospheric modeling.

Lead selection and characterization of antitubercular compounds using the Nested Chemical Library.

PubMed

Sipos, Anna; Pató, János; Székely, Rita; Hartkoorn, Ruben C; Kékesi, László; Őrfi, László; Szántai-Kis, Csaba; Mikušová, Katarína; Svetlíková, Zuzana; Korduláková, Jana; Nagaraja, Valakunja; Godbole, Adwait Anand; Bush, Natassja; Collin, Frédéric; Maxwell, Anthony; Cole, Stewart T; Kéri, György

2015-06-01

Discovering new drugs to treat tuberculosis more efficiently and to overcome multidrug resistance is a world health priority. To find novel antitubercular agents several approaches have been used in various institutions worldwide, including target-based approaches against several validated mycobacterial enzymes and phenotypic screens. We screened more than 17,000 compounds from Vichem's Nested Chemical Library™ using an integrated strategy involving whole cell-based assays with Corynebacterium glutamicum and Mycobacterium tuberculosis, and target-based assays with protein kinases PknA, PknB and PknG as well as other targets such as PimA and bacterial topoisomerases simultaneously. With the help of the target-based approach we have found very potent hits inhibiting the selected target enzymes, but good minimal inhibitory concentrations (MIC) against M. tuberculosis were not achieved. Focussing on the whole cell-based approach several potent hits were found which displayed minimal inhibitory concentrations (MIC) against M. tuberculosis below 10 μM and were non-mutagenic, non-cytotoxic and the targets of some of the hits were also identified. The most active hits represented various scaffolds. Medicinal chemistry-based lead optimization was performed applying various strategies and, as a consequence, a series of novel potent compounds were synthesized. These efforts resulted in some effective potential antitubercular lead compounds which were confirmed in phenotypic assays. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rational and Modular Design of Potent Ligands Targeting the RNA that Causes Myotonic Dystrophy 2

PubMed Central

Lee, Melissa M.; Pushechnikov, Alexei; Disney, Matthew D.

2009-01-01

Most ligands targeting RNA are identified through screening a therapeutic target for binding members of a ligand library. A potential alternative way to construct RNA binders is through rational design using information about the RNA motifs ligands prefer to bind. Herein, we describe such an approach to design modularly assembled ligands targeting the RNA that causes myotonic dystrophy type 2 (DM2), a currently untreatable disease. A previous study identified that 6′-N-5-hexynoate kanamycin A (1) prefers to bind 2×2 nucleotide, pyrimidine-rich RNA internal loops. Multiple copies of such loops were found in the RNA hairpin that causes DM2. The 1 ligand was then modularly displayed on a peptoid scaffold with varied number and spacing to target several internal loops simultaneously. Modularly assembled ligands were tested for binding to a series of RNAs and for inhibiting the formation of the toxic DM2 RNA-muscleblind protein (MBNL-1) interaction. The most potent ligand displays three 1 modules, each separated by four spacing submonomers, and inhibits the formation of the RNA-protein complex with an IC50 of 25 nM. This ligand is higher affinity and more specific for binding DM2 RNA than MBNL-1. It binds the DM2 RNA at least 20-times more tightly than related RNAs and 15-fold more tightly than MBNL-1. A related control peptoid displaying 6′-N-5-hexynoate neamine (2) is >100-fold less potent at inhibiting the RNA-protein interaction and binds to DM2 RNA >125-fold more weakly. Uptake studies into a mouse myoblast cell line also show that the most potent ligand is cell permeable. PMID:19348464

Two Delphinium ramosum chemotypes, their biogeographical distribution and potential toxicity

USDA-ARS?s Scientific Manuscript database

Larkspurs (Delphinium spp.) are poisonous plants found on rangelands throughout Western North America. Two main structural groups of norditerpene alkaloids, the N-(methylsuccinimido) anthranoyllycoctonine type (MSAL-type) and the non-MSAL type, are responsible for larkspur-induced poisoning. Informa...

Global population structure and adaptive evolution of aflatoxin-producing fungi

USDA-ARS?s Scientific Manuscript database

We employed interspecific principal component analyses for six different categories (geography, species, precipitation, temperature, aflatoxin chemotype profile, and mating type) and inferred maximum likelihood phylogenies for six combined loci, including two aflatoxin cluster regions (aflM/alfN and...

A precisely substituted benzopyran targets androgen refractory prostate cancer cells through selective modulation of estrogen receptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Rajeev; Verma, Vikas; Sharma, Vikas

Dietary consumption of phytoestrogens like genistein has been linked with lower incidence of prostate cancer. The estradiol-like benzopyran core of genistein confers estrogen receptor-β (ER-β) selectivity that imparts weak anti-proliferative activity against prostate cancer cells. DL-2-[4-(2-piperidinoethoxy)phenyl]-3-phenyl-2H-1-benzopyran (BP), a SERM designed with benzopyran core, targeted androgen independent prostate cancer (PC-3) cells 14-times more potently than genistein, ~ 25% more efficiently than tamoxifen and 6.5-times more actively than ICI-182780, without forfeiting significant specificity in comparison to genistein. BP increased apoptosis (annexin-V and TUNEL labeling), arrested cell cycle, and significantly increased caspase-3 activity along with mRNA expressions of estrogen receptor (ER)-β and FasLmore » (qPCR) in PC-3 cells. In classical ERE-luc reporter assay BP behaved as a potent ER-α antagonist and ER-β agonist. Accordingly, it decreased expression of ER-α target PS2 (P < 0.01) and increased expression of ER-β target TNF-α (P < 0.05) genes in PC-3. ER-β deficient PC-3 (siRNA-transfected) was resistant to apoptotic and anti-proliferative actions of SERMs, including stimulation of FasL expression by BP. BP significantly inhibited phosphorylation of Akt and ERK-1/2, JNK and p38 in PC-3 (immunoblotting), and thus adopted a multi-pathway mechanism to exert a more potent anti-proliferative activity against prostate cancer cells than natural and synthetic SERMs. Its precise ER-subtype specific activity presents a unique lead structure for further optimization. - Highlights: • BP with benzopyran core of genistein was identified for ER-β selective action. • BP was 14-times more potent than genistien in targeting prostate cancer cells. • It behaved as a potent ER-β agonist and ER-α antagonist in gene reporter assays. • BP's anti-proliferative action was inhibited significantly in ER-β deficient cells. • BP — a unique lead structure for further optimization.« less

Identification of a Potent Tryptophan-based TRPM8 Antagonist With in vivo Analgesic Activity.

PubMed

Bertamino, Alessia; Iraci, Nunzio; Ostacolo, Carmine; Ambrosino, Paolo; Musella, Simona; Di Sarno, Veronica; Ciaglia, Tania; Pepe, Giacomo; Sala, Marina; Soldovieri, Maria Virginia; Mosca, Ilaria; Gonzalez-Rodriguez, Sara; Fernández-Carvajal, Asia; Ferrer-Montiel, Antonio; Novellino, Ettore; Taglialatela, Maurizio; Campiglia, Pietro; Gomez-Monterrey, Isabel M

2018-06-25

TRPM8 has been implicated in nociception and pain and is currently regarded as an attractive target for the pharmacological treatment of neuropathic pain syndromes. A series of analogues of N,N'-dibenzyl tryptamine 1, a potent TRPM8 antagonist, were prepared and screened using a fluorescence-based in vitro assay based on menthol-evoked calcium influx in TRPM8 stably-transfected HEK293 cells. The tryptophan derivative 14 was identified as a potent (IC 50 0.2±0.2 nM) and selective TRPM8 antagonist. In vivo, 14 showed significant target coverage in both an icilin-induced WDS (at 1-30 mg/kg s.c.) and oxaliplatin-induced cold allodynia (at 0.1-1 μg s.c.) mice models. Molecular modeling studies identified the putative binding mode of these antagonists, suggesting that they could influence an interaction network between the S1-4 transmembrane segments and the TRP domains of the channel subunits. The tryptophan moiety provides a new pharmacophoric scaffold for the design of highly potent modulators of TRPM8-mediated pain.

Laboratory and field measurements of enantiomeric monoterpene emissions as a function of chemotype, light and temperature

NASA Astrophysics Data System (ADS)

Song, W.; Staudt, M.; Bourgeois, I.; Williams, J.

2014-03-01

Plants emit significant amounts of monoterpenes into the earth's atmosphere, where they react rapidly to form a multitude of gas phase species and particles. Many monoterpenes exist in mirror-image forms or enantiomers. In this study the enantiomeric monoterpene profile for several representative plants (Quercus ilex L., Rosmarinus officinalis L., and Pinus halepensis Mill.) was investigated as a function of chemotype, light and temperature both in the laboratory and in the field. Analysis of enantiomeric monoterpenes from 19 Quercus ilex individuals from Southern France and Spain revealed four regiospecific chemotypes (genetically fixed emission patterns). In agreement with previous work, only Quercus ilex emissions increased strongly with light. However, for all three plant species no consistent enantiomeric variation was observed as a function of light, and the enantiomeric ratio of α-pinene was found to vary by less than 20% from 100 and 1000 μmol m-2 s-1 PAR (photosynthetically active radiation). The rate of monoterpene emission increased with temperature from all three plant species, but little variation in the enantiomeric distribution of α-pinene was observed with temperature. There was more enantiomeric variability between individuals of the same species than could be induced by either light or temperature. Field measurements of α-pinene enantiomer mixing ratios in the air, taken at a Quercus ilex forest in Southern France, and several other previously reported field enantiomeric ratio diel cycle profiles are compared. All show smoothly varying diel cycles (some positive and some negative) even over changing wind directions. This is surprising in comparison with variations of enantiomeric emission patterns shown by individuals of the same species.

Anxiolytic effects of repeated treatment with an essential oil from Lippia alba and (R)-(-)-carvone in the elevated T-maze.

PubMed

Hatano, V Y; Torricelli, A S; Giassi, A C C; Coslope, L A; Viana, M B

2012-03-01

Lippia alba (Mill.) N.E. Brown (Verbenaceae) is widely used in different regions of Central and South America as a tranquilizer. The plant's anxiolytic properties, however, merit investigation. The present study evaluated the effects of repeated daily (14 days) intraperitoneal (ip) treatment with an essential oil (EO) from a chemotype of L. alba (LA, chemotype II, 12.5 and 25 mg/kg; N = 6-8) and (R)-(-)-carvone (25 mg/kg; N = 8-12), the main constituent of this chemotype, on male Wistar rats (weighing 250 g at the beginning of the experiments) submitted to the elevated T-maze (ETM). The ETM allows the measurement of two defensive responses: inhibitory avoidance and one-way escape. In terms of psychopathology, these responses have been related to generalized anxiety and panic disorder, respectively. Treatment with the EO impaired ETM avoidance latencies, without altering escape, in a way similar to the reference drug diazepam (P < 0.05) (avoidance 2: control = 84.6 ± 35.2; EO 12.5 mg/kg = 11.8 ± 3.8; EO 25 mg/kg = 14.6 ± 2.7; diazepam = 7 ± 2.1). (R)-(-)-carvone also significantly altered this same response (P < 0.05; avoidance 1: control = 91.9 ± 31.5; carvone = 11.6 ± 1.8; diazepam = 8.1 ± 3.3). These results were not due to motor changes since no significant effects were detected in an open field. These observations suggest that LA exerts anxiolytic-like effects on a specific subset of defensive behaviors that have been implicated in generalized anxiety disorder, and suggest that carvone is one of the constituents of LA responsible for its action as a tranquilizer.

Anxiolytic effects of repeated treatment with an essential oil from Lippia alba and (R)-(-)-carvone in the elevated T-maze

PubMed Central

Hatano, V.Y.; Torricelli, A.S.; Giassi, A.C.C.; Coslope, L.A.; Viana, M.B.

2012-01-01

Lippia alba (Mill.) N.E. Brown (Verbenaceae) is widely used in different regions of Central and South America as a tranquilizer. The plant's anxiolytic properties, however, merit investigation. The present study evaluated the effects of repeated daily (14 days) intraperitoneal (ip) treatment with an essential oil (EO) from a chemotype of L. alba (LA, chemotype II, 12.5 and 25 mg/kg; N = 6-8) and (R)-(-)-carvone (25 mg/kg; N = 8-12), the main constituent of this chemotype, on male Wistar rats (weighing 250 g at the beginning of the experiments) submitted to the elevated T-maze (ETM). The ETM allows the measurement of two defensive responses: inhibitory avoidance and one-way escape. In terms of psychopathology, these responses have been related to generalized anxiety and panic disorder, respectively. Treatment with the EO impaired ETM avoidance latencies, without altering escape, in a way similar to the reference drug diazepam (P < 0.05) (avoidance 2: control = 84.6 ± 35.2; EO 12.5 mg/kg = 11.8 ± 3.8; EO 25 mg/kg = 14.6 ± 2.7; diazepam = 7 ± 2.1). (R)-(-)-carvone also significantly altered this same response (P < 0.05; avoidance 1: control = 91.9 ± 31.5; carvone = 11.6 ± 1.8; diazepam = 8.1 ± 3.3). These results were not due to motor changes since no significant effects were detected in an open field. These observations suggest that LA exerts anxiolytic-like effects on a specific subset of defensive behaviors that have been implicated in generalized anxiety disorder, and suggest that carvone is one of the constituents of LA responsible for its action as a tranquilizer. PMID:22358424

Motor Cortical Visuomotor Feedback Activity Is Initially Isolated from Downstream Targets in Output-Null Neural State Space Dimensions.

PubMed

Stavisky, Sergey D; Kao, Jonathan C; Ryu, Stephen I; Shenoy, Krishna V

2017-07-05

Neural circuits must transform new inputs into outputs without prematurely affecting downstream circuits while still maintaining other ongoing communication with these targets. We investigated how this isolation is achieved in the motor cortex when macaques received visual feedback signaling a movement perturbation. To overcome limitations in estimating the mapping from cortex to arm movements, we also conducted brain-machine interface (BMI) experiments where we could definitively identify neural firing patterns as output-null or output-potent. This revealed that perturbation-evoked responses were initially restricted to output-null patterns that cancelled out at the neural population code readout and only later entered output-potent neural dimensions. This mechanism was facilitated by the circuit's large null space and its ability to strongly modulate output-potent dimensions when generating corrective movements. These results show that the nervous system can temporarily isolate portions of a circuit's activity from its downstream targets by restricting this activity to the circuit's output-null neural dimensions. Copyright © 2017 Elsevier Inc. All rights reserved.

Substituted 4-carboxymethylpyroglutamic acid diamides as potent and selective inhibitors of fibroblast activation protein.

PubMed

Tsai, Ting-Yueh; Yeh, Teng-Kuang; Chen, Xin; Hsu, Tsu; Jao, Yu-Chen; Huang, Chih-Hsiang; Song, Jen-Shin; Huang, Yu-Chen; Chien, Chia-Hui; Chiu, Jing-Huai; Yen, Shih-Chieh; Tang, Hung-Kuan; Chao, Yu-Sheng; Jiaang, Weir-Torn

2010-09-23

Fibroblast activation protein (FAP) belongs to the prolyl peptidase family. FAP inhibition is expected to become a new antitumor target. Most known FAP inhibitors often resemble the dipeptide cleavage products, with a boroproline at the P1 site; however, these inhibitors also inhibit DPP-IV, DPP-II, DPP8, and DPP9. Potent and selective FAP inhibitor is needed in evaluating that FAP as a therapeutic target. Therefore, it is important to develop selective FAP inhibitors for the use of target validation. To achieve this, optimization of the nonselective DPP-IV inhibitor 8 led to the discovery of a new class of substituted 4-carboxymethylpyroglutamic acid diamides as FAP inhibitors. SAR studies resulted in a number of FAP inhibitors having IC(50) of <100 nM with excellent selectivity over DPP-IV, DPP-II, DPP8, and DPP9 (IC(50) > 100 μM). Compounds 18a, 18b, and 19 are the only known potent and selective FAP inhibitors, which prompts us to further study the physiological role of FAP.

Synthesis and evaluation of aryl-naloxamide opiate analgesics targeting truncated exon 11-associated μ opioid receptor (MOR-1) splice variants.

PubMed

Majumdar, Susruta; Subrath, Joan; Le Rouzic, Valerie; Polikar, Lisa; Burgman, Maxim; Nagakura, Kuni; Ocampo, Julie; Haselton, Nathan; Pasternak, Anna R; Grinnell, Steven; Pan, Ying-Xian; Pasternak, Gavril W

2012-07-26

3-Iodobenzoylnaltrexamide 1 (IBNtxA) is a potent analgesic acting through a novel receptor target that lack many side-effects of traditional opiates composed, in part, of exon 11-associated truncated six transmembrane domain MOR-1 (6TM/E11) splice variants. To better understand the SAR of this drug target, a number of 4,5-epoxymorphinan analogues were synthesized. Results show the importance of a free 3-phenolic group, a phenyl ring at the 6 position, an iodine at the 3'or 4' position of the phenyl ring, and an N-allyl or c-propylmethyl group to maintain high 6TM/E11 affinity and activity. 3-Iodobenzoylnaloxamide 15 (IBNalA) with a N-allyl group displayed lower δ opioid receptor affinity than its naltrexamine analogue, was 10-fold more potent an analgesic than morphine, elicited no respiratory depression or physical dependence, and only limited inhibition of gastrointestinal transit. Thus, the aryl-naloxamide scaffold can generate a potent analgesic acting through the 6TM/E11 sites with advantageous side-effect profile and greater selectivity.

Drug discovery in tuberculosis. New drug targets and antimycobacterial agents.

PubMed

Campaniço, André; Moreira, Rui; Lopes, Francisca

2018-04-25

Tuberculosis (TB) remains a major health problem worldwide. The infectious agent, Mycobacterium tuberculosis, has a unique ability to survive within the host, alternating between active and latent disease states, and escaping the immune system defences. The extended duration of anti-TB regimens and the increasing prevalence of multidrug- (MDR) and extensively drug-resistant (XDR) M. tuberculosis strains have created an urgent need for new antibiotics active against drug-resistant organisms and that can shorten standard therapy. However, despite success in identifying active compounds through phenotypic screens, the conversion of hits into novel chemical series and ultimately into clinical candidates is hampered by the poor efficacy in eliminating M. tuberculosis within different host compartments, including macrophages, as well as a lack of knowledge about the specific target(s) inhibited and/or upregulated. The current status of anti-TB lead generation has much improved over the last decade, as exemplified by the recent approval of bedaquiline and delamanid to treat MDR-TB and XDR-TB. This review provides a critical analysis on the strategies used to progress hit compounds into viable lead candidates, and how emerging targets may play a role in TB drug discovery in the near future. Four new relevant targets are addressed: the enoyl-acyl carrier protein reductase, InhA; the transmembrane transport protein large, MmpL3; the decaprenylphospho-beta-d-ribofuranose 2-oxidase, DprE1; and the ubiquinol-cytochrome C reductase, QcrB. Validated hit compounds for each target are presented and explored, and the medicinal chemistry strategies to expand SAR around novel chemotypes analyzed. In addition, very recent emerging targets are also discussed. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Tumor radiosensitization by monomethyl auristatin E: mechanism of action and targeted delivery

PubMed Central

Crisp, Jessica L.; Jones, Karra A.; Hicks, Angel M.; Scanderbeg, Daniel J.; Nguyen, Quyen T.; Sicklick, Jason K.; Lowy, Andrew M.; Tsien, Roger Y.; Advani, Sunil J.

2015-01-01

Intrinsic tumor resistance to radiotherapy limits the efficacy of ionizing radiation (IR). Sensitizing cancer cells specifically to IR would improve tumor control and decrease normal tissue toxicity. The development of tumor targeting technologies allows for developing potent radiosensitizing drugs. We hypothesized that the anti-tubulin agent monomethyl auristatin E (MMAE), a component of a clinically approved antibody-directed conjugate, could function as a potent radiosensitizer and be selectively delivered to tumors using an activatable cell penetrating peptide targeting matrix metalloproteinases and RGD binding integrins (ACPP-cRGD-MMAE). We evaluated the ability of MMAE to radiosensitize both established cancer cells and a low passage cultured human pancreatic tumor cell line using clonogenic and DNA damage assays. MMAE sensitized colorectal and pancreatic cancer cells to IR in a schedule and dose dependent manner correlating with mitotic arrest. Radiosensitization was evidenced by decreased clonogenic survival and increased DNA double strand breaks in irradiated cells treated with MMAE. MMAE in combination with IR resulted in increased DNA damage signaling and activation of CHK1. To test a therapeutic strategy of MMAE and IR, PANC-1 or HCT-116 murine tumor xenografts were treated with non-targeted free MMAE or tumor targeted MMAE (ACPP-cRGD-MMAE). While free MMAE in combination with IR resulted in tumor growth delay, tumor targeted ACPP-cRGD-MMAE with IR produced a more robust and significantly prolonged tumor regression in xenograft models. Our studies identify MMAE as a potent radiosensitizer. Importantly, MMAE radiosensitization can be localized to tumors by targeted activatable cell penetrating peptides. PMID:25681274

Use of Chemotypes for Profiling and Exploring the ToxCast Chemical-Assay Landscape (ACS Spring meeting)

EPA Science Inventory

EPA's ToxCast chemical library, currently exceeding 4000 unique chemicals, has successfully captured a broad diversity of chemical use-types, functionality, and structures and features potentially relevant to toxicity and environmental exposure landscapes. Chemical diversity in ...

Phylogenetic examination of two chemotypes of Lupinus leucophyllus

USDA-ARS?s Scientific Manuscript database

Lupines (Lupinus spp.) are a common legume found on western U.S. rangelands. Lupinus spp. may contain quinolizidine and or piperidine alkaloids that could be toxic and or teratogenic to grazing livestock. Lupinus leucohyllus and Lupinus polyphyllus represent important species in the rangelands of ...

Linalool from Lippia alba: study of the reproducibility of the essential oil profile and the enantiomeric purity.

PubMed

Siani, Antonio C; Tappin, Marcelo R R; Ramos, Mônica F S; Mazzei, José L; Ramos, Maria Conceição K V; De Aquino Neto, Francisco R; Frighetto, Nélson

2002-06-05

A new chemotype of the aromatic Verbenaceae species Lippia alba Mill. N. E. Br. from southeastern Brazil has recently been shown to have a high content of linalool in the leaf essential oil. Vegetative propagation of this chemotype was conducted at six different locations in Brazil, and the variation of the content and the optical purity of linalool in the oils were verified. Yields (0.6-0.9%, hydrodistillation), chemical composition, linalool content, and optical purity of the oils from all the plants were compared, using GC-FID, GC-MS, chiral chromatography, and retention index calculation. No plant exceeded the matrix in linalool content (46.5 to 90.7%), and the chemical profile of the oils was the same for all the samples. Purification of linalool to a content close to 100% was effected by vacuum distillation of the crude oil. Chiral analysis showed exclusively the presence of S-linalool in all the crude oils and in the distilled samples.

Essential Oil of Thymus munbyanus subsp. coloratus from Algeria: Chemotypification and in vitro Biological Activities.

PubMed

Bendif, Hamdi; Boudjeniba, Messaoud; Miara, Mohamed Djamel; Biqiku, Loreta; Bramucci, Massimo; Lupidi, Giulio; Quassinti, Luana; Vitali, Luca A; Maggi, Filippo

2017-03-01

Thymus munbyanus subsp. coloratus (Lamiaceae) is a small shrub endemic to Algeria and Morocco where is found in lawns, rockeries and mountainous regions. From a phytochemical point of view this taxon has never been characterized. In this work we have analysed the chemical compositions of the essential oils obtained from inflorescences and vegetative parts by GC/MS. A new chemotype, i.e. borneol-chemotype, was characterized for the first time in the species. Furthermore, we assessed the biological activities of essential oils, namely the antioxidant, antimicrobial and cytotoxicity on tumor cells that were evaluated by the DPPH, ABTS, and FRAP, disc diffusion, and MTT methods, respectively. Biological assays highlighted a moderate inhibitory effect on Staphylococcus aureus, Escherichia coli and Candida albicans (inhibition zone diameter in the range 9 - 10 mm), and noteworthy cytotoxicity on A375 human melanoma cells (IC 50 of 46.95 μg/ml). © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Identification of a New Zinc Binding Chemotype by Fragment Screening.

PubMed

Chrysanthopoulos, Panagiotis K; Mujumdar, Prashant; Woods, Lucy A; Dolezal, Olan; Ren, Bin; Peat, Thomas S; Poulsen, Sally-Ann

2017-09-14

The discovery of a new zinc binding chemotype from screening a nonbiased fragment library is reported. Using the orthogonal fragment screening methods of native state mass spectrometry and surface plasmon resonance a 3-unsubstituted 2,4-oxazolidinedione fragment was found to have low micromolar binding affinity to the zinc metalloenzyme carbonic anhydrase II (CA II). This affinity approached that of fragment sized primary benzenesulfonamides, the classical zinc binding group found in most CA II inhibitors. Protein X-ray crystallography established that 3-unsubstituted 2,4-oxazolidinediones bound to CA II via an interaction of the acidic ring nitrogen with the CA II active site zinc, as well as two hydrogen bonds between the oxazolidinedione ring oxygen and the CA II protein backbone. Furthermore, 3-unsubstituted 2,4-oxazolidinediones appear to be a viable starting point for the development of an alternative class of CA inhibitor, wherein the medicinal chemistry pedigree of primary sulfonamides has dominated for several decades.

Potent Neutralization of Vaccinia Virus by Divergent Murine Antibodies Targeting a Common Site of Vulnerability in L1 Protein

PubMed Central

Kaever, Thomas; Meng, Xiangzhi; Matho, Michael H.; Schlossman, Andrew; Li, Sheng; Sela-Culang, Inbal; Ofran, Yanay; Buller, Mark; Crump, Ryan W.; Parker, Scott; Frazier, April; Crotty, Shane; Zajonc, Dirk M.; Peters, Bjoern

2014-01-01

ABSTRACT Vaccinia virus (VACV) L1 is an important target for viral neutralization and has been included in multicomponent DNA or protein vaccines against orthopoxviruses. To further understand the protective mechanism of the anti-L1 antibodies, we generated five murine anti-L1 monoclonal antibodies (MAbs), which clustered into 3 distinct epitope groups. While two groups of anti-L1 failed to neutralize, one group of 3 MAbs potently neutralized VACV in an isotype- and complement-independent manner. This is in contrast to neutralizing antibodies against major VACV envelope proteins, such as H3, D8, or A27, which failed to completely neutralize VACV unless the antibodies are of complement-fixing isotypes and complement is present. Compared to nonneutralizing anti-L1 MAbs, the neutralization antibodies bound to the recombinant L1 protein with a significantly higher affinity and also could bind to virions. By using a variety of techniques, including the isolation of neutralization escape mutants, hydrogen/deuterium exchange mass spectrometry, and X-ray crystallography, the epitope of the neutralizing antibodies was mapped to a conformational epitope with Asp35 as the key residue. This epitope is similar to the epitope of 7D11, a previously described potent VACV neutralizing antibody. The epitope was recognized mainly by CDR1 and CDR2 of the heavy chain, which are highly conserved among antibodies recognizing the epitope. These antibodies, however, had divergent light-chain and heavy-chain CDR3 sequences. Our study demonstrates that the conformational L1 epitope with Asp35 is a common site of vulnerability for potent neutralization by a divergent group of antibodies. IMPORTANCE Vaccinia virus, the live vaccine for smallpox, is one of the most successful vaccines in human history, but it presents a level of risk that has become unacceptable for the current population. Studying the immune protection mechanism of smallpox vaccine is important for understanding the basic principle of successful vaccines and the development of next-generation, safer vaccines for highly pathogenic orthopoxviruses. We studied antibody targets in smallpox vaccine by developing potent neutralizing antibodies against vaccinia virus and comprehensively characterizing their epitopes. We found a site in vaccinia virus L1 protein as the target of a group of highly potent murine neutralizing antibodies. The analysis of antibody-antigen complex structure and the sequences of the antibody genes shed light on how these potent neutralizing antibodies are elicited from immunized mice. PMID:25031354

Discovery of tanshinone derivatives with anti-MRSA activity via targeted bio-transformation.

PubMed

He, Wenni; Liu, Miaomiao; Huang, Pei; Abdel-Mageed, Wael M; Han, Jianying; Watrous, Jeramie D; Nguyen, Don D; Wang, Wenzhao; Song, Fuhang; Dai, Huanqin; Zhang, Jingyu; Quinn, Ronald J; Grkovi, Tanja; Luo, Houwei; Zhang, Lixin; Liu, Xueting

2016-09-01

Two potent anti-MRSA tanshinone glycosides ( 1 and 2 ) were discovered by targeted microbial biotransformation, along with rapid identification via MS/MS networking. Serial reactions including dehydrogenation, demethylations, reduction, glycosylation and methylation have been observed after incubation of tanshinone IIA and fungus Mucor rouxianus AS 3.3447. In addition, tanshinosides B ( 2 ) showed potent activities against serial clinical isolates of oxacillin-resistant Staphylococcus aureus with MIC values of 0.78 μg/mL. This is the first study that shows a significant increase in the level and activities of tanshinone glycosides relative to the substrate tanshinone IIA.

Five-Year Longitudinal Assessment (2008 to 2012) of E-101 Solution Activity against Clinical Target and Antimicrobial-Resistant Pathogens

PubMed Central

Pillar, Chris M.; Sahm, Daniel F.; O'Hanley, Peter; Stephens, Jackson T.

2014-01-01

This study summarizes the topical E-101 solution susceptibility testing results for 760 Gram-positive and Gram-negative target pathogens collected from 75 U.S. sites between 2008 and 2012 and 103 ESKAPE pathogens. E-101 solution maintained potent activity against all bacterial species studied for each year tested, with MICs ranging from <0.008 to 0.25 μg porcine myeloperoxidase (pMPO)/ml. These results confirm that E-101 solution retains its potent broad-spectrum activity against U.S. clinical isolates and organisms with challenging resistance phenotypes. PMID:24841272

Synthesis and in Vitro and in Vivo Evaluation of Phosphoinositide-3-kinase Inhibitors.

PubMed

Burger, Matthew T; Knapp, Mark; Wagman, Allan; Ni, Zhi-Jie; Hendrickson, Thomas; Atallah, Gordana; Zhang, Yanchen; Frazier, Kelly; Verhagen, Joelle; Pfister, Keith; Ng, Simon; Smith, Aaron; Bartulis, Sarah; Merrit, Hanne; Weismann, Marion; Xin, Xiaohua; Haznedar, Joshua; Voliva, Charles F; Iwanowicz, Ed; Pecchi, Sabina

2011-01-13

Phospoinositide-3-kinases (PI3K) are important oncology targets due to the deregulation of this signaling pathway in a wide variety of human cancers. A series of 2-morpholino, 4-substituted, 6-(3-hydroxyphenyl) pyrimidines have been reported as potent inhibitors of PI3Ks. Herein, we describe the structure-guided optimization of these pyrimidines with a focus on replacing the phenol moiety, while maintaining potent target inhibition and improving in vivo properties. A series of 2-morpholino, 4-substituted, 6-heterocyclic pyrimidines, which potently inhibit PI3K, were discovered. Within this series a compound, 17, was identified with suitable pharmacokinetic (PK) properties, which allowed for the establishment of a PI3K PK/pharmacodynamic-efficacy relationship as determined by in vivo inhibition of AKT(Ser473) phosphorylation and tumor growth inhibition in a mouse A2780 tumor xenograft model.

Synthesis and in Vitro and in Vivo Evaluation of Phosphoinositide-3-kinase Inhibitors

PubMed Central

2010-01-01

Phospoinositide-3-kinases (PI3K) are important oncology targets due to the deregulation of this signaling pathway in a wide variety of human cancers. A series of 2-morpholino, 4-substituted, 6-(3-hydroxyphenyl) pyrimidines have been reported as potent inhibitors of PI3Ks. Herein, we describe the structure-guided optimization of these pyrimidines with a focus on replacing the phenol moiety, while maintaining potent target inhibition and improving in vivo properties. A series of 2-morpholino, 4-substituted, 6-heterocyclic pyrimidines, which potently inhibit PI3K, were discovered. Within this series a compound, 17, was identified with suitable pharmacokinetic (PK) properties, which allowed for the establishment of a PI3K PK/pharmacodynamic−efficacy relationship as determined by in vivo inhibition of AKTSer473 phosphorylation and tumor growth inhibition in a mouse A2780 tumor xenograft model. PMID:24900252

Development and Validation of 2D Difference Intensity Analysis for Chemical Library Screening by Protein-Detected NMR Spectroscopy.

PubMed

Egner, John M; Jensen, Davin R; Olp, Michael D; Kennedy, Nolan W; Volkman, Brian F; Peterson, Francis C; Smith, Brian C; Hill, R Blake

2018-03-02

An academic chemical screening approach was developed by using 2D protein-detected NMR, and a 352-chemical fragment library was screened against three different protein targets. The approach was optimized against two protein targets with known ligands: CXCL12 and BRD4. Principal component analysis reliably identified compounds that induced nonspecific NMR crosspeak broadening but did not unambiguously identify ligands with specific affinity (hits). For improved hit detection, a novel scoring metric-difference intensity analysis (DIA)-was devised that sums all positive and negative intensities from 2D difference spectra. Applying DIA quickly discriminated potential ligands from compounds inducing nonspecific NMR crosspeak broadening and other nonspecific effects. Subsequent NMR titrations validated chemotypes important for binding to CXCL12 and BRD4. A novel target, mitochondrial fission protein Fis1, was screened, and six hits were identified by using DIA. Screening these diverse protein targets identified quinones and catechols that induced nonspecific NMR crosspeak broadening, hampering NMR analyses, but are currently not computationally identified as pan-assay interference compounds. The results established a streamlined screening workflow that can easily be scaled and adapted as part of a larger screening pipeline to identify fragment hits and assess relative binding affinities in the range of 0.3-1.6 mm. DIA could prove useful in library screening and other applications in which NMR chemical shift perturbations are measured. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transfer of genetic therapy across human populations: molecular targets for increasing patient coverage in repeat expansion diseases

PubMed Central

Varela, Miguel A; Curtis, Helen J; Douglas, Andrew GL; Hammond, Suzan M; O'Loughlin, Aisling J; Sobrido, Maria J; Scholefield, Janine; Wood, Matthew JA

2016-01-01

Allele-specific gene therapy aims to silence expression of mutant alleles through targeting of disease-linked single-nucleotide polymorphisms (SNPs). However, SNP linkage to disease varies between populations, making such molecular therapies applicable only to a subset of patients. Moreover, not all SNPs have the molecular features necessary for potent gene silencing. Here we provide knowledge to allow the maximisation of patient coverage by building a comprehensive understanding of SNPs ranked according to their predicted suitability toward allele-specific silencing in 14 repeat expansion diseases: amyotrophic lateral sclerosis and frontotemporal dementia, dentatorubral-pallidoluysian atrophy, myotonic dystrophy 1, myotonic dystrophy 2, Huntington's disease and several spinocerebellar ataxias. Our systematic analysis of DNA sequence variation shows that most annotated SNPs are not suitable for potent allele-specific silencing across populations because of suboptimal sequence features and low variability (>97% in HD). We suggest maximising patient coverage by selecting SNPs with high heterozygosity across populations, and preferentially targeting SNPs that lead to purine:purine mismatches in wild-type alleles to obtain potent allele-specific silencing. We therefore provide fundamental knowledge on strategies for optimising patient coverage of therapeutics for microsatellite expansion disorders by linking analysis of population genetic variation to the selection of molecular targets. PMID:25990798

Transfer of genetic therapy across human populations: molecular targets for increasing patient coverage in repeat expansion diseases.

PubMed

Varela, Miguel A; Curtis, Helen J; Douglas, Andrew G L; Hammond, Suzan M; O'Loughlin, Aisling J; Sobrido, Maria J; Scholefield, Janine; Wood, Matthew J A

2016-02-01

Allele-specific gene therapy aims to silence expression of mutant alleles through targeting of disease-linked single-nucleotide polymorphisms (SNPs). However, SNP linkage to disease varies between populations, making such molecular therapies applicable only to a subset of patients. Moreover, not all SNPs have the molecular features necessary for potent gene silencing. Here we provide knowledge to allow the maximisation of patient coverage by building a comprehensive understanding of SNPs ranked according to their predicted suitability toward allele-specific silencing in 14 repeat expansion diseases: amyotrophic lateral sclerosis and frontotemporal dementia, dentatorubral-pallidoluysian atrophy, myotonic dystrophy 1, myotonic dystrophy 2, Huntington's disease and several spinocerebellar ataxias. Our systematic analysis of DNA sequence variation shows that most annotated SNPs are not suitable for potent allele-specific silencing across populations because of suboptimal sequence features and low variability (>97% in HD). We suggest maximising patient coverage by selecting SNPs with high heterozygosity across populations, and preferentially targeting SNPs that lead to purine:purine mismatches in wild-type alleles to obtain potent allele-specific silencing. We therefore provide fundamental knowledge on strategies for optimising patient coverage of therapeutics for microsatellite expansion disorders by linking analysis of population genetic variation to the selection of molecular targets.

Identifying apicoplast-targeting antimalarials using high-throughput compatible approaches

PubMed Central

Ekland, Eric H.; Schneider, Jessica; Fidock, David A.

2011-01-01

Malarial parasites have evolved resistance to all previously used therapies, and recent evidence suggests emerging resistance to the first-line artemisinins. To identify antimalarials with novel mechanisms of action, we have developed a high-throughput screen targeting the apicoplast organelle of Plasmodium falciparum. Antibiotics known to interfere with this organelle, such as azithromycin, exhibit an unusual phenotype whereby the progeny of drug-treated parasites die. Our screen exploits this phenomenon by assaying for “delayed death” compounds that exhibit a higher potency after two cycles of intraerythrocytic development compared to one. We report a primary assay employing parasites with an integrated copy of a firefly luciferase reporter gene and a secondary flow cytometry-based assay using a nucleic acid stain paired with a mitochondrial vital dye. Screening of the U.S. National Institutes of Health Clinical Collection identified known and novel antimalarials including kitasamycin. This inexpensive macrolide, used for agricultural applications, exhibited an in vitro IC50 in the 50 nM range, comparable to the 30 nM activity of our control drug, azithromycin. Imaging and pharmacologic studies confirmed kitasamycin action against the apicoplast, and in vivo activity was observed in a murine malaria model. These assays provide the foundation for high-throughput campaigns to identify novel chemotypes for combination therapies to treat multidrug-resistant malaria.—Ekland, E. H., Schneider, J., Fidock, D. A. Identifying apicoplast-targeting antimalarials using high-throughput compatible approaches. PMID:21746861

Cell- and Tissue-based Proteome Profiling and Bioimaging with the Probes Derived from a Potent AXL Kinase Inhibitor.

PubMed

Li, Zhengqiu; Zheng, Binbin; Guo, Haijun; Xu, Jiaqian; Ma, Nan; Ni, Yun; Li, Lin; Hao, Piliang; Ding, Ke

2018-06-25

AXL has been defined as a novel target for cancer therapeutics. However, only a few potent and selective inhibitors targeting AXL are available to date. Our group has developed a lead compound, 9im, capable of excellent inhibition against AXL. With the aim of understanding its cellular and tissue mechanism of actions and direct subsequent structure optimization, a study on competitive affinity-based proteome profiling and bioimaging was carried out. A series of unknown cellular and tissue targets, including RYK, PCK, ATP1A3, EIF4A, Ptprn and Cox5b were discovered. In addition, trans-cyclooctene (TCO) and acedan-containing probes were developed to image the binding between 9im and its target proteins inside live cells and tumor tissues. These probes would be useful tools in the detection of expression and activity of AXL. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Masitinib (AB1010), a Potent and Selective Tyrosine Kinase Inhibitor Targeting KIT

PubMed Central

Dubreuil, Patrice; Letard, Sébastien; Ciufolini, Marco; Gros, Laurent; Humbert, Martine; Castéran, Nathalie; Borge, Laurence; Hajem, Bérengère; Lermet, Anne; Sippl, Wolfgang; Voisset, Edwige; Arock, Michel; Auclair, Christian; Leventhal, Phillip S.; Mansfield, Colin D.; Moussy, Alain; Hermine, Olivier

2009-01-01

Background The stem cell factor receptor, KIT, is a target for the treatment of cancer, mastocytosis, and inflammatory diseases. Here, we characterise the in vitro and in vivo profiles of masitinib (AB1010), a novel phenylaminothiazole-type tyrosine kinase inhibitor that targets KIT. Methodology/Principal Findings In vitro, masitinib had greater activity and selectivity against KIT than imatinib, inhibiting recombinant human wild-type KIT with an half inhibitory concentration (IC50) of 200±40 nM and blocking stem cell factor-induced proliferation and KIT tyrosine phosphorylation with an IC50 of 150±80 nM in Ba/F3 cells expressing human or mouse wild-type KIT. Masitinib also potently inhibited recombinant PDGFR and the intracellular kinase Lyn, and to a lesser extent, fibroblast growth factor receptor 3. In contrast, masitinib demonstrated weak inhibition of ABL and c-Fms and was inactive against a variety of other tyrosine and serine/threonine kinases. This highly selective nature of masitinib suggests that it will exhibit a better safety profile than other tyrosine kinase inhibitors; indeed, masitinib-induced cardiotoxicity or genotoxicity has not been observed in animal studies. Molecular modelling and kinetic analysis suggest a different mode of binding than imatinib, and masitinib more strongly inhibited degranulation, cytokine production, and bone marrow mast cell migration than imatinib. Furthermore, masitinib potently inhibited human and murine KIT with activating mutations in the juxtamembrane domain. In vivo, masitinib blocked tumour growth in mice with subcutaneous grafts of Ba/F3 cells expressing a juxtamembrane KIT mutant. Conclusions Masitinib is a potent and selective tyrosine kinase inhibitor targeting KIT that is active, orally bioavailable in vivo, and has low toxicity. PMID:19789626

Targeting of Repeated Sequences Unique to a Gene Results in Significant Increases in Antisense Oligonucleotide Potency

PubMed Central

Vickers, Timothy A.; Freier, Susan M.; Bui, Huynh-Hoa; Watt, Andrew; Crooke, Stanley T.

2014-01-01

A new strategy for identifying potent RNase H-dependent antisense oligonucleotides (ASOs) is presented. Our analysis of the human transcriptome revealed that a significant proportion of genes contain unique repeated sequences of 16 or more nucleotides in length. Activities of ASOs targeting these repeated sites in several representative genes were compared to those of ASOs targeting unique single sites in the same transcript. Antisense activity at repeated sites was also evaluated in a highly controlled minigene system. Targeting both native and minigene repeat sites resulted in significant increases in potency as compared to targeting of non-repeated sites. The increased potency at these sites is a result of increased frequency of ASO/RNA interactions which, in turn, increases the probability of a productive interaction between the ASO/RNA heteroduplex and human RNase H1 in the cell. These results suggest a new, highly efficient strategy for rapid identification of highly potent ASOs. PMID:25334092

Visualizing Trumps Vision in Training Attention.

PubMed

Reinhart, Robert M G; McClenahan, Laura J; Woodman, Geoffrey F

2015-07-01

Mental imagery can have powerful training effects on behavior, but how this occurs is not well understood. Here we show that even a single instance of mental imagery can improve attentional selection of a target more effectively than actually practicing visual search. By recording subjects' brain activity, we found that these imagery-induced training effects were due to perceptual attention being more effectively focused on targets following imagined training. Next, we examined the downside of this potent training by changing the target after several trials of training attention with imagery and found that imagined search resulted in more potent interference than actual practice following these target changes. Finally, we found that proactive interference from task-irrelevant elements in the visual displays appears to underlie the superiority of imagined training relative to actual practice. Our findings demonstrate that visual attention mechanisms can be effectively trained to select target objects in the absence of visual input, and this results in more effective control of attention than practicing the task itself. © The Author(s) 2015.

Imidazopyridine-Based Fatty Acid Synthase Inhibitors That Show Anti-HCV Activity and in Vivo Target Modulation.

PubMed

Oslob, Johan D; Johnson, Russell J; Cai, Haiying; Feng, Shirley Q; Hu, Lily; Kosaka, Yuko; Lai, Julie; Sivaraja, Mohanram; Tep, Samnang; Yang, Hanbiao; Zaharia, Cristiana A; Evanchik, Marc J; McDowell, Robert S

2013-01-10

Potent imidazopyridine-based inhibitors of fatty acid synthase (FASN) are described. The compounds are shown to have antiviral (HCV replicon) activities that track with their biochemical activities. The most potent analogue (compound 19) also inhibits rat FASN and inhibits de novo palmitate synthesis in vitro (cell-based) as well as in vivo.

Imidazopyridine-Based Fatty Acid Synthase Inhibitors That Show Anti-HCV Activity and in Vivo Target Modulation

PubMed Central

2012-01-01

Potent imidazopyridine-based inhibitors of fatty acid synthase (FASN) are described. The compounds are shown to have antiviral (HCV replicon) activities that track with their biochemical activities. The most potent analogue (compound 19) also inhibits rat FASN and inhibits de novo palmitate synthesis in vitro (cell-based) as well as in vivo. PMID:24900571

Tumor radiosensitization by monomethyl auristatin E: mechanism of action and targeted delivery.

PubMed

Buckel, Lisa; Savariar, Elamprakash N; Crisp, Jessica L; Jones, Karra A; Hicks, Angel M; Scanderbeg, Daniel J; Nguyen, Quyen T; Sicklick, Jason K; Lowy, Andrew M; Tsien, Roger Y; Advani, Sunil J

2015-04-01

Intrinsic tumor resistance to radiotherapy limits the efficacy of ionizing radiation (IR). Sensitizing cancer cells specifically to IR would improve tumor control and decrease normal tissue toxicity. The development of tumor-targeting technologies allows for developing potent radiosensitizing drugs. We hypothesized that the anti-tubulin agent monomethyl auristatin E (MMAE), a component of a clinically approved antibody-directed conjugate, could function as a potent radiosensitizer and be selectively delivered to tumors using an activatable cell-penetrating peptide targeting matrix metalloproteinases and RGD-binding integrins (ACPP-cRGD-MMAE). We evaluated the ability of MMAE to radiosensitize both established cancer cells and a low-passage cultured human pancreatic tumor cell line using clonogenic and DNA damage assays. MMAE sensitized colorectal and pancreatic cancer cells to IR in a schedule- and dose-dependent manner, correlating with mitotic arrest. Radiosensitization was evidenced by decreased clonogenic survival and increased DNA double-strand breaks in irradiated cells treated with MMAE. MMAE in combination with IR resulted in increased DNA damage signaling and activation of CHK1. To test a therapeutic strategy of MMAE and IR, PANC-1 or HCT-116 murine tumor xenografts were treated with nontargeted free MMAE or tumor-targeted MMAE (ACPP-cRGD-MMAE). While free MMAE in combination with IR resulted in tumor growth delay, tumor-targeted ACPP-cRGD-MMAE with IR produced a more robust and significantly prolonged tumor regression in xenograft models. Our studies identify MMAE as a potent radiosensitizer. Importantly, MMAE radiosensitization can be localized to tumors by targeted activatable cell-penetrating peptides. ©2015 American Association for Cancer Research.

Targeting protein-protein interactions with trimeric ligands: high affinity inhibitors of the MAGUK protein family.

PubMed

Nissen, Klaus B; Haugaard-Kedström, Linda M; Wilbek, Theis S; Nielsen, Line S; Åberg, Emma; Kristensen, Anders S; Bach, Anders; Jemth, Per; Strømgaard, Kristian

2015-01-01

PDZ domains in general, and those of PSD-95 in particular, are emerging as promising drug targets for diseases such as ischemic stroke. We have previously shown that dimeric ligands that simultaneously target PDZ1 and PDZ2 of PSD-95 are highly potent inhibitors of PSD-95. However, PSD-95 and the related MAGUK proteins contain three consecutive PDZ domains, hence we envisioned that targeting all three PDZ domains simultaneously would lead to more potent and potentially more specific interactions with the MAGUK proteins. Here we describe the design, synthesis and characterization of a series of trimeric ligands targeting all three PDZ domains of PSD-95 and the related MAGUK proteins, PSD-93, SAP-97 and SAP-102. Using our dimeric ligands targeting the PDZ1-2 tandem as starting point, we designed novel trimeric ligands by introducing a PDZ3-binding peptide moiety via a cysteine-derivatized NPEG linker. The trimeric ligands generally displayed increased affinities compared to the dimeric ligands in fluorescence polarization binding experiments and optimized trimeric ligands showed low nanomolar inhibition towards the four MAGUK proteins, thus being the most potent inhibitors described. Kinetic experiments using stopped-flow spectrometry showed that the increase in affinity is caused by a decrease in the dissociation rate of the trimeric ligand as compared to the dimeric ligands, likely reflecting the lower probability of simultaneous dissociation of all three PDZ ligands. Thus, we have provided novel inhibitors of the MAGUK proteins with exceptionally high affinity, which can be used to further elucidate the therapeutic potential of these proteins.

20180311 - Use of ToxPrint chemotypes for exploring chemical feature enrichments across the ToxCast chemical-assay landscape (SOT)

EPA Science Inventory

EPA’s ToxCast chemical library spans diverse chemical use-types, functionalities, structures and features potentially relevant to toxicity and environmental exposure. However, this structural diversity, along with assay noise and low average hit rates across the varied Tox...

Effects of elevated CO2 on the swainsonine chemotypes of Astragalus lentiginosus and Astragalus mollissimus

USDA-ARS?s Scientific Manuscript database

Rapid changes in the Earth’s atmosphere and climate associated with human activity can have significant impacts on agricultural and livestock production. CO2 concentrations, representing one of many atmospheric changes, have risen from the industrial revolution to the current time, and are expected...

Use of Knowledge-informed Chemotypes to Explore the ToxCast/Tox21 Chemical-Data Landscape (OpenTox)

EPA Science Inventory

The ToxCast and Tox21 chemical libraries currently exceed 3000 and 9000 unique chemicals, respectively, and span a broad diversity of chemical use-types, functionality, and toxicity mechanism and endpoint space. These libraries function as mechanism probes across hundreds of hig...

Use of ToxPrint chemotypes for exploring chemical feature enrichments across the ToxCast chemical-assay landscape

EPA Science Inventory

EPA’s ToxCast chemical library spans diverse chemical use-types, functionalities, structures and features potentially relevant to toxicity and environmental exposure. However, this structural diversity, along with assay noise and low average hit rates across the varied ToxCast h...

Quantitative determination of seven chemical constituents and chemo-type differentiation of chamomiles using high-performance thin-layer chromatography

USDA-ARS?s Scientific Manuscript database

Matricaria recutita L. (German Chamomile), Anthemis nobilis L. (Roman Chamomile) and Chrysanthemum morifolium Ramat are commonly used chamomiles. High performance thin layer chromatographic (HPTLC) method was developed for estimation of six flavonoids (rutin, luteolin-7-O-ß-glucoside, chamaemeloside...

Promising Aedes aegypti repellent chemotypes identified through integrated QSAE, virtual screening, synthesis, and bioassay

USDA-ARS?s Scientific Manuscript database

Molecular field topology analysis, scaffold hopping, and molecular docking were used as complementary computational tools for the design of repellents for Aedes aegypti, the insect vector for yellow fever, West Nile fever, and dengue fever. A large number of analogues were evaluated by virtual scree...

Identification of a lycopsamine-N-oxide chemotype of Amsinckia intermedia

USDA-ARS?s Scientific Manuscript database

In February 2012, an apparent poisoning outbreak in cattle occurred on rangeland infested with Amsinckia intermedia near Kingman, Arizona. Plant samples were collected from the location every month from the time of the poisoning outbreak through to when the plant seeded and senesced in May 2012. A...

White snakeroot poisoning in goats: Variations in toxicity with different plant chemotypes

USDA-ARS?s Scientific Manuscript database

White Snakeroot is a toxic plant that causes human and livestock diseases known as the trembles and milk sickness and historically devastated entire settlements. White snakeroot toxins, which differ significantly in plant populations, were initially identified as tremetol which is thought to be mix...

A knowledge-informed chemotype approach to mining the ToxCast/Tox21 chemical-data landscape (WC9)

EPA Science Inventory

ToxCast and Tox21 chemical libraries currently exceed 2000 and 8000 unique chemicals, respectively, and span a broad diversity of chemical use-types, functionality, and toxicity mechanism and endpoint space. These libraries function as mechanism probes across hundreds of high-th...

A New Publicly Available Chemical Query Language, CSRML, to support Chemotype Representations for Application to Data-Mining and Modeling

EPA Science Inventory

A new XML-based query language, CSRML, has been developed for representing chemical substructures, molecules, reaction rules, and reactions. CSRML queries are capable of integrating additional forms of information beyond the simple substructure (e.g., SMARTS) or reaction transfor...

Recreational drug discovery: natural products as lead structures for the synthesis of smart drugs.

PubMed

Appendino, Giovanni; Minassi, Alberto; Taglialatela-Scafati, Orazio

2014-07-01

Covering: up to December 2013. Over the past decade, there has been a growing transition in recreational drugs from natural materials (marijuana, hashish, opium), natural products (morphine, cocaine), or their simple derivatives (heroin), to synthetic agents more potent than their natural prototypes, which are sometimes less harmful in the short term, or that combine properties from different classes of recreational prototypes. These agents have been named smart drugs, and have become popular both for personal consumption and for collective intoxication at rave parties. The reasons for this transition are varied, but are mainly regulatory and commercial. New analogues of known illegal intoxicants are invisible to most forensic detection techniques, while the alleged natural status and the lack of avert acute toxicity make them appealing to a wide range of users. On the other hand, the advent of the internet has made possible the quick dispersal of information among users and the on-line purchase of these agents and/or the precursors for their synthesis. Unlike their natural products chemotypes (ephedrine, mescaline, cathinone, psilocybin, THC), most new drugs of abuse are largely unfamiliar to the organic chemistry community as well as to health care providers. To raise awareness of the growing plague of smart drugs we have surveyed, in a medicinal chemistry fashion, their development from natural products leads, their current methods of production, and the role that clandestine home laboratories and underground chemists have played in the surge of popularity of these drugs.

Synthesis and evaluation of aryl-naloxamide opiate analgesics targeting truncated exon 11-associated mu opioid receptor (MOR-1) splice variants

PubMed Central

Majumdar, Susruta; Subrath, Joan; Le Rouzic, Valerie; Polikar, Lisa; Burgman, Maxim; Nagakura, Kuni; Ocampo, Julie; Haselton, Nathan; Pasternak, Anna R.; Grinnell, Steven; Pan, Ying-Xian; Pasternak, Gavril W.

2012-01-01

3-Iodobenzoylnaltrexamide 1 (IBNtxA) is a potent analgesic acting through a novel receptor target that lack many side-effects of traditional opiates composed, in part, of exon 11-associated truncated six transmembrane domain MOR-1 (6TM/E11) splice variants. To better understand the SAR of this drug target, a number of 4,5-epoxymorphinan analogs were synthesized. Results show the importance of a free 3-phenolic group, a phenyl ring at the 6 position, an iodine at the 3′ or 4′ position of the phenyl ring and an N-allyl or c-propylmethyl group to maintain high 6TM/E11 affinity and activity. 3-Iodobenzoylnaloxamide 15 (IBNalA) with a N-allyl group displayed lower delta opioid receptor affinity than its naltrexamine analog, was 10-fold more potent an analgesic than morphine, elicited no respiratory depression or physical dependence and only limited inhibition of gastrointestinal transit. Thus, the aryl-naloxamide scaffold can generate a potent analgesic acting through the 6TM/E11 sites with advantageous side-effect profile and greater selectivity. PMID:22734622

Screening North American plant extracts in vitro against Trypanosoma brucei for discovery of new antitrypanosomal drug leads.

PubMed

Jain, Surendra; Jacob, Melissa; Walker, Larry; Tekwani, Babu

2016-05-18

Human African Trypanosomiasis (HAT) is a protozoan parasitic disease caused by Trypanosoma brucei. The disease is endemic in regions of sub-Saharan Africa, covering 36 countries and more than 60 million people at the risk. Only few drugs are available for the treatment of HAT. Current drugs suffer from severe toxicities and require intramuscular or intravenous administrations. The situation is further aggravated due to the emergence of drug resistance. There is an urgent need of new drugs that are effective orally against both stages of HAT. Natural products offer an unmatched source for bioactive molecules with new chemotypes. The extracts prepared from 522 plants collected from various parts of the North America were screened in vitro against blood stage trypamastigote forms of T. brucei. Active extracts were further screened at concentrations ranging from 10 to 0.4 μg/mL. Active extracts were also investigated for toxicity in Differentiated THP1 cells at 10 μg/mL concentration. The results were computed for dose-response analysis and determination of IC50/IC90 values. A significant number (150) of extracts showed >90 % inhibition of growth of trypomastigote blood forms of T. brucei in primary screening at 20 μg/mL concentration. The active extracts were further investigated for dose-response inhibition of T. brucei growth. The antitrypansomal activity of 125 plant extracts was confirmed with IC50 < 10 μg/mL. None of these active extracts showed toxicity against differentiated THP1 cells. Eight plants extracts namely, Alnus rubra, Hoita macrostachya, Sabal minor, Syzygium aqueum, Hamamelis virginiana, Coccoloba pubescens, Rhus integrifolia and Nuphar luteum were identified as highly potent antitrypanosomal extracts with IC50 values <1 μg/mL. Limited phytochemical and pharmacological reports are available for the lead plant extracts with potent antitrypanosomal activity. Follow up evaluation of these plant extracts is likely to yield new antitrypanosomal drug-leads or alternate medicines for treatment of HAT.

Drug Discovery Targeting Bromodomain-Containing Protein 4

PubMed Central

2017-01-01

BRD4, the most extensively studied member of the BET family, is an epigenetic regulator that localizes to DNA via binding to acetylated histones and controls the expression of therapeutically important gene regulatory networks through the recruitment of transcription factors to form mediator complexes, phosphorylating RNA polymerase II, and by its intrinsic histone acetyltransferase activity. Disrupting the protein–protein interactions between BRD4 and acetyl-lysine has been shown to effectively block cell proliferation in cancer, cytokine production in acute inflammation, and so forth. To date, significant efforts have been devoted to the development of BRD4 inhibitors, and consequently, a dozen have progressed to human clinical trials. Herein, we summarize the advances in drug discovery and development of BRD4 inhibitors by focusing on their chemotypes, in vitro and in vivo activity, selectivity, relevant mechanisms of action, and therapeutic potential. Opportunities and challenges to achieve selective and efficacious BRD4 inhibitors as a viable therapeutic strategy for human diseases are also highlighted. PMID:28195723

Dynamic undocking and the quasi-bound state as tools for drug discovery

NASA Astrophysics Data System (ADS)

Ruiz-Carmona, Sergio; Schmidtke, Peter; Luque, F. Javier; Baker, Lisa; Matassova, Natalia; Davis, Ben; Roughley, Stephen; Murray, James; Hubbard, Rod; Barril, Xavier

2017-03-01

There is a pressing need for new technologies that improve the efficacy and efficiency of drug discovery. Structure-based methods have contributed towards this goal but they focus on predicting the binding affinity of protein-ligand complexes, which is notoriously difficult. We adopt an alternative approach that evaluates structural, rather than thermodynamic, stability. As bioactive molecules present a static binding mode, we devised dynamic undocking (DUck), a fast computational method to calculate the work necessary to reach a quasi-bound state at which the ligand has just broken the most important native contact with the receptor. This non-equilibrium property is surprisingly effective in virtual screening because true ligands form more-resilient interactions than decoys. Notably, DUck is orthogonal to docking and other 'thermodynamic' methods. We demonstrate the potential of the docking-undocking combination in a fragment screening against the molecular chaperone and oncology target Hsp90, for which we obtain novel chemotypes and a hit rate that approaches 40%.

wALADin benzimidazoles differentially modulate the function of porphobilinogen synthase orthologs.

PubMed

Lentz, Christian S; Halls, Victoria S; Hannam, Jeffrey S; Strassel, Silke; Lawrence, Sarah H; Jaffe, Eileen K; Famulok, Michael; Hoerauf, Achim; Pfarr, Kenneth M

2014-03-27

The heme biosynthesis enzyme porphobilinogen synthase (PBGS) is a potential drug target in several human pathogens. wALADin1 benzimidazoles have emerged as species-selective PBGS inhibitors against Wolbachia endobacteria of filarial worms. In the present study, we have systematically tested wALADins against PBGS orthologs from bacteria, protozoa, metazoa, and plants to elucidate the inhibitory spectrum. However, the effect of wALADin1 on different PBGS orthologs was not limited to inhibition: several orthologs were stimulated by wALADin1; others remained unaffected. We demonstrate that wALADins allosterically modulate the PBGS homooligomeric equilibrium with inhibition mediated by favoring low-activity oligomers, while 5-aminolevulinic acid, Mg(2+), or K(+) stabilized high-activity oligomers. Pseudomonas aeruginosa PBGS could be inhibited or stimulated by wALADin1 depending on these factors and pH. We have defined the wALADin chemotypes responsible for either inhibition or stimulation, facilitating the design of tailored PBGS modulators for potential application as antimicrobial agents, herbicides, or drugs for porphyric disorders.

wALADin Benzimidazoles Differentially Modulate the Function of Porphobilinogen Synthase Orthologs

PubMed Central

2015-01-01

The heme biosynthesis enzyme porphobilinogen synthase (PBGS) is a potential drug target in several human pathogens. wALADin1 benzimidazoles have emerged as species-selective PBGS inhibitors against Wolbachia endobacteria of filarial worms. In the present study, we have systematically tested wALADins against PBGS orthologs from bacteria, protozoa, metazoa, and plants to elucidate the inhibitory spectrum. However, the effect of wALADin1 on different PBGS orthologs was not limited to inhibition: several orthologs were stimulated by wALADin1; others remained unaffected. We demonstrate that wALADins allosterically modulate the PBGS homooligomeric equilibrium with inhibition mediated by favoring low-activity oligomers, while 5-aminolevulinic acid, Mg2+, or K+ stabilized high-activity oligomers. Pseudomonas aeruginosa PBGS could be inhibited or stimulated by wALADin1 depending on these factors and pH. We have defined the wALADin chemotypes responsible for either inhibition or stimulation, facilitating the design of tailored PBGS modulators for potential application as antimicrobial agents, herbicides, or drugs for porphyric disorders. PMID:24568185

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Huixian; Wacker, Daniel; Mileni, Mauro

Opioid receptors mediate the actions of endogenous and exogenous opioids on many physiological processes, including the regulation of pain, respiratory drive, mood, and - in the case of {kappa}-opioid receptor ({kappa}-OR) - dysphoria and psychotomimesis. Here we report the crystal structure of the human {kappa}-OR in complex with the selective antagonist JDTic, arranged in parallel dimers, at 2.9 {angstrom} resolution. The structure reveals important features of the ligand-binding pocket that contribute to the high affinity and subtype selectivity of JDTic for the human {kappa}-OR. Modelling of other important {kappa}-OR-selective ligands, including the morphinan-derived antagonists norbinaltorphimine and 5'-guanidinonaltrindole, and the diterpenemore » agonist salvinorin A analogue RB-64, reveals both common and distinct features for binding these diverse chemotypes. Analysis of site-directed mutagenesis and ligand structure-activity relationships confirms the interactions observed in the crystal structure, thereby providing a molecular explanation for {kappa}-OR subtype selectivity, and essential insights for the design of compounds with new pharmacological properties targeting the human {kappa}-OR.« less

mRNA-engineered mesenchymal stem cells for targeted delivery of interleukin-10 to sites of inflammation.

PubMed

Levy, Oren; Zhao, Weian; Mortensen, Luke J; Leblanc, Sarah; Tsang, Kyle; Fu, Moyu; Phillips, Joseph A; Sagar, Vinay; Anandakumaran, Priya; Ngai, Jessica; Cui, Cheryl H; Eimon, Peter; Angel, Matthew; Lin, Charles P; Yanik, Mehmet Fatih; Karp, Jeffrey M

2013-10-03

Mesenchymal stem cells (MSCs) are promising candidates for cell-based therapy to treat several diseases and are compelling to consider as vehicles for delivery of biological agents. However, MSCs appear to act through a seemingly limited "hit-and-run" mode to quickly exert their therapeutic impact, mediated by several mechanisms, including a potent immunomodulatory secretome. Furthermore, MSC immunomodulatory properties are highly variable and the secretome composition following infusion is uncertain. To determine whether a transiently controlled antiinflammatory MSC secretome could be achieved at target sites of inflammation, we harnessed mRNA transfection to generate MSCs that simultaneously express functional rolling machinery (P-selectin glycoprotein ligand-1 [PSGL-1] and Sialyl-Lewis(x) [SLeX]) to rapidly target inflamed tissues and that express the potent immunosuppressive cytokine interleukin-10 (IL-10), which is not inherently produced by MSCs. Indeed, triple-transfected PSGL-1/SLeX/IL-10 MSCs transiently increased levels of IL-10 in the inflamed ear and showed a superior antiinflammatory effect in vivo, significantly reducing local inflammation following systemic administration. This was dependent on rapid localization of MSCs to the inflamed site. Overall, this study demonstrates that despite the rapid clearance of MSCs in vivo, engineered MSCs can be harnessed via a "hit-and-run" action for the targeted delivery of potent immunomodulatory factors to treat distant sites of inflammation.

Comparative pharmacology of flatworm and roundworm glutamate-gated chloride channels: Implications for potential anthelmintics.

PubMed

Lynagh, Timothy; Cromer, Brett A; Dufour, Vanessa; Laube, Bodo

2014-12-01

Pharmacological targeting of glutamate-gated chloride channels (GluCls) is a potent anthelmintic strategy, evidenced by macrocyclic lactones that eliminate numerous roundworm infections by activating roundworm GluCls. Given the recent identification of flatworm GluCls and the urgent need for drugs against schistosomiasis, flatworm GluCls should be evaluated as potential anthelmintic targets. This study sought to identify agonists or modulators of one such GluCl, SmGluCl-2 from the parasitic flatworm Schistosoma mansoni. The effects of nine glutamate-like compounds and three monoterpenoid ion channel modulators were measured by electrophysiology at SmGluCl-2 recombinantly expressed in Xenopus laevis oocytes. For comparison with an established anthelmintic target, experiments were also performed on the AVR-14B GluCl from the parasitic roundworm Haemonchus contortus. l-Glutamate was the most potent agonist at both GluCls, but l-2-aminoadipate, d-glutamate and d-2-aminoadipate activated SmGluCl-2 (EC50 1.0 ± 0.1 mM, 2.4 ± 0.4 mM, 3.6 ± 0.7 mM, respectively) more potently than AVR-14B. Quisqualate activated only SmGluCl-2 whereas l-aspartate activated only AVR-14B GluCls. Regarding the monoterpenoids, both GluCls were inhibited by propofol, thymol and menthol, SmGluCl-2 most potently by thymol (IC50 484 ± 85 μM) and least potently by menthol (IC50 > 3 mM). Computational docking suggested that agonist and inhibitor potency is attributable to particular interactions with extracellular or membrane-spanning amino acid residues. These results reveal that flatworm GluCls are pharmacologically susceptible to numerous agonists and modulators and indicate that changes to the glutamate γ-carboxyl or to the propofol 6-isopropyl group can alter the differential pharmacology at flatworm and roundworm GluCls. This should inform the development of more potent compounds and in turn lead to novel anthelmintics.

Indolyl Azaspiroketal Mannich Bases Are Potent Antimycobacterial Agents with Selective Membrane Permeabilizing Effects and in Vivo Activity.

PubMed

Nyantakyi, Samuel Agyei; Li, Ming; Gopal, Pooja; Zimmerman, Matthew; Dartois, Véronique; Gengenbacher, Martin; Dick, Thomas; Go, Mei-Lin

2018-06-25

The inclusion of an azaspiroketal Mannich base in the membrane targeting antitubercular 6-methoxy-1- n-octyl-1 H-indole scaffold resulted in analogs with improved selectivity and submicromolar activity against Mycobacterium tuberculosis H37Rv. The potency enhancing properties of the spiro-fused ring motif was affirmed by SAR and validated in a mouse model of tuberculosis. As expected for membrane inserting agents, the indolyl azaspiroketal Mannich bases perturbed phospholipid vesicles, permeabilized bacterial cells, and induced the mycobacterial cell envelope stress reporter promoter p iniBAC. Surprisingly, their membrane disruptive effects did not appear to be associated with bacterial membrane depolarization. This profile was not uniquely associated with azaspiroketal Mannich bases but was characteristic of indolyl Mannich bases as a class. Whereas resistant mycobacteria could not be isolated for a less potent indolyl Mannich base, the more potent azaspiroketal analog displayed low spontaneous resistance mutation frequency of 10 -8 /CFU. This may indicate involvement of an additional envelope-related target in its mechanism of action.

Tear gasses CN, CR, and CS are potent activators of the human TRPA1 receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brone, Bert; Peeters, Pieter J.; Marrannes, Roger

2008-09-01

The TRPA1 channel is activated by a number of pungent chemicals, such as allylisothiocyanate, present in mustard oil and thiosulfinates present in garlic. Most of the known activating compounds contain reactive, electrophilic chemical groups, reacting with cysteine residues in the active site of the TRPA1 channel. This covalent modification results in activation of the channel and has been shown to be reversible for several ligands. Commonly used tear gasses CN, CR and CS are also pungent chemicals, and in this study we show that they are extremely potent and selective activators of the human TRPA1 receptor. To our knowledge, thesemore » are the most potent TRPA1 agonists known to date. The identification of the molecular target for these tear gasses may open up possibilities to alleviate the effects of tear gasses via treatment with TRPA1 antagonists. In addition these results may contribute to the basic knowledge of the TRPA1 channel that is gaining importance as a pharmacological target.« less

Halogenated Phenazines that Potently Eradicate Biofilms, MRSA Persister Cells in Non-Biofilm Cultures, and Mycobacterium tuberculosis.

PubMed

Garrison, Aaron T; Abouelhassan, Yasmeen; Kallifidas, Dimitris; Bai, Fang; Ukhanova, Maria; Mai, Volker; Jin, Shouguang; Luesch, Hendrik; Huigens, Robert W

2015-12-01

Conventional antibiotics are ineffective against non-replicating bacteria (for example, bacteria within biofilms). We report a series of halogenated phenazines (HP), inspired by marine antibiotic 1, that targets persistent bacteria. HP 14 demonstrated the most potent biofilm eradication activities to date against MRSA, MRSE, and VRE biofilms (MBEC = 0.2-12.5 μM), as well as the effective killing of MRSA persister cells in non-biofilm cultures. Frontline MRSA treatments, vancomycin and daptomycin, were unable to eradicate MRSA biofilms or non-biofilm persisters alongside 14. HP 13 displayed potent antibacterial activity against slow-growing M. tuberculosis (MIC = 3.13 μM), the leading cause of death by bacterial infection around the world. HP analogues effectively target persistent bacteria through a mechanism that is non-toxic to mammalian cells and could have a significant impact on treatments for chronic bacterial infections. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Targeting the Allosteric Site of Oncoprotein BCR-ABL as an Alternative Strategy for Effective Target Protein Degradation.

PubMed

Shimokawa, Kenichiro; Shibata, Norihito; Sameshima, Tomoya; Miyamoto, Naoki; Ujikawa, Osamu; Nara, Hiroshi; Ohoka, Nobumichi; Hattori, Takayuki; Cho, Nobuo; Naito, Mikihiko

2017-10-12

Protein degradation technology based on hybrid small molecules is an emerging drug modality that has significant potential in drug discovery and as a unique method of post-translational protein knockdown in the field of chemical biology. Here, we report the first example of a novel and potent protein degradation inducer that binds to an allosteric site of the oncogenic BCR-ABL protein. BCR-ABL allosteric ligands were incorporated into the SNIPER (Specific and Nongenetic inhibitor of apoptosis protein [IAP]-dependent Protein Erasers) platform, and a series of in vitro biological assays of binding affinity, target protein modulation, signal transduction, and growth inhibition were carried out. One of the designed compounds, 6 (SNIPER(ABL)-062), showed desirable binding affinities against ABL1, cIAP1/2, and XIAP and consequently caused potent BCR-ABL degradation.

Multilocus Genotyping and Molecular Phylogenetics Resolve a Novel Head Blight Pathogen within the Fusarium graminearum Species Complex from Ethiopia

USDA-ARS?s Scientific Manuscript database

A survey of Fusarium head blight (FHB)-contaminated wheat in Ethiopia recovered 31 isolates resembling members of the Fusarium graminearum species complex. Results of a multilocus genotyping (MLGT) assay for FHB species and trichothecene chemotype determination suggested that 22 of these isolates m...

Predicting ToxCast™ and Tox21 Bioactivity Using Toxprint Chemotypes (WC10)

EPA Science Inventory

The EPA ToxCast™ and Tox21 programs have generated bioactivity data for nearly 9076 chemicals across ~1192 assay endpoints; however, for over 70% of the chemical-assay endpoint pairs there is no data. To help fill the gaps, we constructed random forest models for each assay endpo...

Ligand-guided optimization of CXCR4 homology models for virtual screening using a multiple chemotype approach

NASA Astrophysics Data System (ADS)

Neves, Marco A. C.; Simões, Sérgio; Sá e Melo, M. Luisa

2010-12-01

CXCR4 is a G-protein coupled receptor for CXCL12 that plays an important role in human immunodeficiency virus infection, cancer growth and metastasization, immune cell trafficking and WHIM syndrome. In the absence of an X-ray crystal structure, theoretical modeling of the CXCR4 receptor remains an important tool for structure-function analysis and to guide the discovery of new antagonists with potential clinical use. In this study, the combination of experimental data and molecular modeling approaches allowed the development of optimized ligand-receptor models useful for elucidation of the molecular determinants of small molecule binding and functional antagonism. The ligand-guided homology modeling approach used in this study explicitly re-shaped the CXCR4 binding pocket in order to improve discrimination between known CXCR4 antagonists and random decoys. Refinement based on multiple test-sets with small compounds from single chemotypes provided the best early enrichment performance. These results provide an important tool for structure-based drug design and virtual ligand screening of new CXCR4 antagonists.

[Detection of endotoxins of Gram-negative bacteria on the basis of electromagnetic radiation frequency spectrum].

PubMed

Likhoded, V G; Kuleshova, N V; Sergieva, N V; Konev, Iu V; Trubnikova, I A; Sudzhian, E V

2007-01-01

Method of Gram-negative bacteria endotoxins detection on the basis of their own spectrum of electromagnetic radiation frequency was developed. Frequency spectrum typical for chemotype Re glycolipid, which is a part of lypopolysaccharides in the majority of Gram-negative bacteria, was used. Two devices--"Mini- Expert-DT" (manufactured by IMEDIS, Moscow) and "Bicom" (manufactured by Regumed, Germany)--were used as generators of electromagnetic radiation. Detection of endotoxin using these devices was performed by electropuncture vegetative resonance test. Immunoenzyme reaction with antibodies to chemotype Re glycolipid was used during analysis of preparations for assessment of resonance-frequency method specificity. The study showed that resonance-frequency method can detect lypopolysaccharides of different enterobacteria in quantities up to 0.1 pg as well as bacteria which contain lypopolysaccharides. At the same time, this method does not detect such bacteria as Staphylococcus aureus, Bifidobacterium spp., Lactobacillus spp., and Candida albicans. The method does not require preliminary processing of blood samples and can be used for diagnostics of endotoxinemia, and detection of endotoxins in blood samples or injection solutions.

Mycotoxin production and cytotoxicity of Fusarium strains isolated from Norwegian cereals.

PubMed

Langseth, W; Bernhoft, A; Rundberget, T; Kosiak, B; Gareis, M

Thirty-four isolates of the eight most common Fusarium species isolated from Norwegian cereals; F. avenaceum, F. culmorum, F. equiseti, F. graminearum, F. poae, F. sporotrichioides, F. torulosum and F. tricinctum were studied for their cytotoxicity and ability to produce mycotoxins. The strains were cultivated on rice, and analysed for trichothecenes (all species), zearalenone (all species), fusarochromanone (F. equiseti), wortmannin (F. torulosum), moniliformin and enniatins (F. avenaceum, F. tricinctum and F. torulosum). The cytotoxicity of the extracts were examined with an (in vitro) MTT-cell culture assay. All F. graminearum and five of seven F. culmorum isolates belonged to chemotype IA, producing deoxynivalenol and 3-acetyl-deoxynivalenol, while the two other F. culmorum strains were nivalenol producers (chemotype II). The F. equiseti isolates and one of the F. poae isolates produced both type A and B trichothecenes, and relatively large quantities of fusarochromanone were detected in the F. equiseti cultures. All Fusarium species studied showed significant cytotoxicity, but with a large variation between species, and also within each species. F. sporotrichioides and F. equiseti showed the highest average cytotoxicity.

Discovery of a small-molecule inhibitor of Dvl-CXXC5 interaction by computational approaches

NASA Astrophysics Data System (ADS)

Ma, Songling; Choi, Jiwon; Jin, Xuemei; Kim, Hyun-Yi; Yun, Ji-Hye; Lee, Weontae; Choi, Kang-Yell; No, Kyoung Tai

2018-05-01

The Wnt/β-catenin signaling pathway plays a significant role in the control of osteoblastogenesis and bone formation. CXXC finger protein 5 (CXXC5) has been recently identified as a negative feedback regulator of osteoblast differentiation through a specific interaction with Dishevelled (Dvl) protein. It was reported that targeting the Dvl-CXXC5 interaction could be a novel anabolic therapeutic target for osteoporosis. In this study, complex structure of Dvl PDZ domain and CXXC5 peptide was simulated with molecular dynamics (MD). Based on the structural analysis of binding modes of MD-simulated Dvl PDZ domain with CXXC5 peptide and crystal Dvl PDZ domain with synthetic peptide-ligands, we generated two different pharmacophore models and applied pharmacophore-based virtual screening to discover potent inhibitors of the Dvl-CXXC5 interaction for the anabolic therapy of osteoporosis. Analysis of 16 compounds selected by means of a virtual screening protocol yielded four compounds that effectively disrupted the Dvl-CXXC5 interaction in the fluorescence polarization assay. Potential compounds were validated by fluorescence spectroscopy and nuclear magnetic resonance. We successfully identified a highly potent inhibitor, BMD4722, which directly binds to the Dvl PDZ domain and disrupts the Dvl-CXXC5 interaction. Overall, CXXC5-Dvl PDZ domain complex based pharmacophore combined with various traditional and simple computational methods is a promising approach for the development of modulators targeting the Dvl-CXXC5 interaction, and the potent inhibitor BMD4722 could serve as a starting point to discover or design more potent and specific the Dvl-CXXC5 interaction disruptors.

Potent influenza A virus entry inhibitors targeting a conserved region of hemagglutinin.

PubMed

Lin, Dongguo; Luo, Yinzhu; Yang, Guang; Li, Fangfang; Xie, Xiangkun; Chen, Daiwei; He, Lifang; Wang, Jingyu; Ye, Chunfeng; Lu, Shengsheng; Lv, Lin; Liu, Shuwen; He, Jian

2017-11-15

Influenza A viruses (IAVs) induce acute respiratory disease and cause significant morbidity and mortality throughout the world. With the emergence of drug-resistant viral strains, new and effective anti-IAV drugs with different modes of action are urgently needed. In this study, by conjugating cholesterol to the N-terminus of the short peptide KKWK, a lipopeptide named S-KKWK was created. The anti-IAV test indicated that S-KKWK and its derivatives displayed potent antiviral activities against a broad variety of influenza A viral strains including oseltamivir-resistant strains and clinically relevant isolates with IC 50 values ranging from 0.7 to 3.0µM. An extensive mechanistic study showed that these peptides functioned as viral "entry blockers" by inhibiting the conformational rearrangements of HA2 subunit, thereby interrupting the fusion of virus-host cell membranes. Significantly, a computer-aided docking simulation and protein sequence alignment identified conserved residues in the stem region of HA2 as the possible binding site of S-KKWK, which may be employed as a potential drug target for designing anti-IAVs with a broad-spectrum of activity. By targeting this region, a potent anti-IAV agent was subsequently created. In addition, the anti-IAV activity of S-KKWK was assessed by experiments with influenza A virus-infected mice, in which S-KKWK reduced the mortality of infected animals and extended survival time significantly. Overall, in addition to providing a strategy for designing broad-spectrum anti-IAV agents, these results indicate that S-KKWK and its derivatives are prospective candidates for potent antivirals. Copyright © 2017 Elsevier Inc. All rights reserved.

Ebselen exerts antifungal activity by regulating glutathione (GSH) and reactive oxygen species (ROS) production in fungal cells.

PubMed

Thangamani, Shankar; Eldesouky, Hassan E; Mohammad, Haroon; Pascuzzi, Pete E; Avramova, Larisa; Hazbun, Tony R; Seleem, Mohamed N

2017-01-01

Ebselen, an organoselenium compound and a clinically safe molecule has been reported to possess potent antifungal activity, but its antifungal mechanism of action and in vivo antifungal activity remain unclear. The antifungal effect of ebselen was tested against Candida albicans, C. glabrata, C. tropicalis, C. parapsilosis, Cryptococcus neoformans, and C. gattii clinical isolates. Chemogenomic profiling and biochemical assays were employed to identify the antifungal target of ebselen. Ebselen's antifungal activity in vivo was investigated in a Caenorhabditis elegans animal model. Ebselen exhibits potent antifungal activity against both Candida spp. and Cryptococcus spp., at concentrations ranging from 0.5 to 2μg/ml. Ebselen rapidly eradicates a high fungal inoculum within 2h of treatment. Investigation of the drug's antifungal mechanism of action indicates that ebselen depletes intracellular glutathione (GSH) levels, leading to increased production of reactive oxygen species (ROS), and thereby disturbs the redox homeostasis in fungal cells. Examination of ebselen's in vivo antifungal activity in two Caenorhabditis elegans models of infection demonstrate that ebselen is superior to conventional antifungal drugs (fluconazole, flucytosine and amphotericin) in reducing Candida and Cryptococcus fungal load. Ebselen possesses potent antifungal activity against clinically relevant isolates of both Candida and Cryptococcus by regulating GSH and ROS production. The potent in vivo antifungal activity of ebselen supports further investigation for repurposing it for use as an antifungal agent. The present study shows that ebselen targets glutathione and also support that glutathione as a potential target for antifungal drug development. Copyright © 2016 Elsevier B.V. All rights reserved.

Discovery of a small-molecule inhibitor of Dvl-CXXC5 interaction by computational approaches.

PubMed

Ma, Songling; Choi, Jiwon; Jin, Xuemei; Kim, Hyun-Yi; Yun, Ji-Hye; Lee, Weontae; Choi, Kang-Yell; No, Kyoung Tai

2018-05-01

The Wnt/β-catenin signaling pathway plays a significant role in the control of osteoblastogenesis and bone formation. CXXC finger protein 5 (CXXC5) has been recently identified as a negative feedback regulator of osteoblast differentiation through a specific interaction with Dishevelled (Dvl) protein. It was reported that targeting the Dvl-CXXC5 interaction could be a novel anabolic therapeutic target for osteoporosis. In this study, complex structure of Dvl PDZ domain and CXXC5 peptide was simulated with molecular dynamics (MD). Based on the structural analysis of binding modes of MD-simulated Dvl PDZ domain with CXXC5 peptide and crystal Dvl PDZ domain with synthetic peptide-ligands, we generated two different pharmacophore models and applied pharmacophore-based virtual screening to discover potent inhibitors of the Dvl-CXXC5 interaction for the anabolic therapy of osteoporosis. Analysis of 16 compounds selected by means of a virtual screening protocol yielded four compounds that effectively disrupted the Dvl-CXXC5 interaction in the fluorescence polarization assay. Potential compounds were validated by fluorescence spectroscopy and nuclear magnetic resonance. We successfully identified a highly potent inhibitor, BMD4722, which directly binds to the Dvl PDZ domain and disrupts the Dvl-CXXC5 interaction. Overall, CXXC5-Dvl PDZ domain complex based pharmacophore combined with various traditional and simple computational methods is a promising approach for the development of modulators targeting the Dvl-CXXC5 interaction, and the potent inhibitor BMD4722 could serve as a starting point to discover or design more potent and specific the Dvl-CXXC5 interaction disruptors.

Dual mTORC2/mTORC1 targeting results in potent suppressive effects on acute myeloid leukemia (AML) progenitors*

PubMed Central

Altman, Jessica K.; Sassano, Antonella; Kaur, Surinder; Glaser, Heather; Kroczynska, Barbara; Redig, Amanda J.; Russo, Suzanne; Barr, Sharon; Platanias, Leonidas C.

2011-01-01

Purpose To determine whether mTORC2 and RI-mTORC1 complexes are present in AML cells and to examine the effects of dual mTORC2/mTORC1 inhibition on primitive AML leukemic progenitors. Experimental Design Combinations of different experimental approaches were used, including immunoblotting to detect phosphorylated/activated forms of elements of the mTOR pathway in leukemic cell lines and primary AML blasts; cell proliferation assays; direct assessment of mRNA translation in polysomal fractions of leukemic cells; and clonogenic assays in methylcellulose to evaluate leukemic progenitor colony formation. Results mTORC2 complexes are active in AML cells and play critical roles in leukemogenesis. Rapamycin insensitive (RI) mTORC1 complexes are also formed and regulate the activity of the translational repressor 4E-BP1 in AML cells. OSI-027, blocks mTORC1 and mTORC2 activities and suppresses mRNA translation of cyclin D1 and other genes that mediate proliferative responses in AML cells. Moreover, OSI-027 acts as a potent suppressor of primitive leukemic precursors from AML patients and is much more effective than rapamycin in eliciting antileukemic effects in vitro. Conclusions Dual targeting of mTORC2 and mTORC1 results in potent suppressive effects on primitive leukemic progenitors from AML patients. Inhibition of the mTOR catalytic site with OSI-027 results in suppression of both mTORC2 and RI-mTORC1 complexes and elicits much more potent antileukemic responses than selective mTORC1 targeting with rapamycin. PMID:21415215

Discovery of a small-molecule inhibitor of Dvl-CXXC5 interaction by computational approaches

NASA Astrophysics Data System (ADS)

Ma, Songling; Choi, Jiwon; Jin, Xuemei; Kim, Hyun-Yi; Yun, Ji-Hye; Lee, Weontae; Choi, Kang-Yell; No, Kyoung Tai

2018-04-01

The Wnt/β-catenin signaling pathway plays a significant role in the control of osteoblastogenesis and bone formation. CXXC finger protein 5 (CXXC5) has been recently identified as a negative feedback regulator of osteoblast differentiation through a specific interaction with Dishevelled (Dvl) protein. It was reported that targeting the Dvl-CXXC5 interaction could be a novel anabolic therapeutic target for osteoporosis. In this study, complex structure of Dvl PDZ domain and CXXC5 peptide was simulated with molecular dynamics (MD). Based on the structural analysis of binding modes of MD-simulated Dvl PDZ domain with CXXC5 peptide and crystal Dvl PDZ domain with synthetic peptide-ligands, we generated two different pharmacophore models and applied pharmacophore-based virtual screening to discover potent inhibitors of the Dvl-CXXC5 interaction for the anabolic therapy of osteoporosis. Analysis of 16 compounds selected by means of a virtual screening protocol yielded four compounds that effectively disrupted the Dvl-CXXC5 interaction in the fluorescence polarization assay. Potential compounds were validated by fluorescence spectroscopy and nuclear magnetic resonance. We successfully identified a highly potent inhibitor, BMD4722, which directly binds to the Dvl PDZ domain and disrupts the Dvl-CXXC5 interaction. Overall, CXXC5-Dvl PDZ domain complex based pharmacophore combined with various traditional and simple computational methods is a promising approach for the development of modulators targeting the Dvl-CXXC5 interaction, and the potent inhibitor BMD4722 could serve as a starting point to discover or design more potent and specific the Dvl-CXXC5 interaction disruptors.

Screening for small molecule inhibitors of Toxoplasma gondii.

PubMed

Kortagere, Sandhya

2012-12-01

Toxoplasma gondii, the agent that causes toxoplasmosis, is an opportunistic parasite that infects many mammalian species. It is an obligate intracellular parasite that causes severe congenital neurological and ocular disease mostly in immunocompromised humans. The current regimen of therapy includes only a few medications that often lead to hypersensitivity and toxicity. In addition, there are no vaccines available to prevent the transmission of this agent. Therefore, safer and more effective medicines to treat toxoplasmosis are urgently needed. The author presents in silico and in vitro strategies that are currently used to screen for novel targets and unique chemotypes against T. gondii. Furthermore, this review highlights the screening technologies and characterization of some novel targets and new chemical entities that could be developed into highly efficacious treatments for toxoplasmosis. A number of diverse methods are being used to design inhibitors against T. gondii. These include ligand-based methods, in which drugs that have been shown to be efficacious against other Apicomplexa parasites can be repurposed to identify lead molecules against T. gondii. In addition, structure-based methods use currently available repertoire of structural information in various databases to rationally design small-molecule inhibitors of T. gondii. Whereas the screening methods have their advantages and limitations, a combination of methods is ideally suited to design small-molecule inhibitors of complex parasites such as T. gondii.

Novel application of the published kinase inhibitor set to identify therapeutic targets and pathways in triple negative breast cancer subtypes

PubMed Central

Phamduy, Theresa B.; Chrisey, Douglas B.

2017-01-01

Triple negative breast cancers (TNBCs) have high recurrence and metastasis rates. Acquisition of a mesenchymal morphology and phenotype in addition to driving migration is a consequential process that promotes metastasis. Although some kinases are known to regulate a mesenchymal phenotype, the role for a substantial portion of the human kinome remains uncharacterized. Here we evaluated the Published Kinase Inhibitor Set (PKIS) and screened a panel of TNBC cell lines to evaluate the compounds’ effects on a mesenchymal phenotype. Our screen identified 36 hits representative of twelve kinase inhibitor chemotypes based on reversal of the mesenchymal cell morphology, which was then prioritized to twelve compounds based on gene expression and migratory behavior analyses. We selected the most active compound and confirmed mesenchymal reversal on transcript and protein levels with qRT-PCR and Western Blot. Finally, we utilized a kinase array to identify candidate kinases responsible for the EMT reversal. This investigation shows the novel application to identify previously unrecognized kinase pathways and targets in acquisition of a mesenchymal TNBC phenotype that warrant further investigation. Future studies will examine specific roles of the kinases in mechanisms responsible for acquisition of the mesenchymal and/or migratory phenotype. PMID:28771473

The Endocannabinoid System as a Target for Treatment of Breast Cancer

DTIC Science & Technology

2010-08-01

psychoactive constituent of marijuana (Gaoni and Mechoulam, 1964), as well as other naturally occurring and synthetically derived cannabinoids bind to and...the primary psychoactive constituent present in marijuana , and WIN55,212-2, a highly potent, full CB1 receptor agonist. Female mice implanted with...potent and highly efficacious synthetic cannabinoid receptor agonist originally developed as a nonsteroidal anti-inflammatory drug (Ward et al., 1991

Development of Non-Hormonal Steroids for the Treatment of Duchenne Muscular Dystrophy

DTIC Science & Technology

2013-02-01

rat models of irritant contact dermatitis and allergic contact dermatitis showed that this compound exerted potent anti- inflammatory activity...conditions such as arthriti dermatitis , asthma, muscular dystrophy, and auto-immune disor ders.20–22 However, glucocorticoids have many off-target effect...commonly pre- scribed drugs due to their potent anti-inflammatory properties, and remain standard of care in many conditions such as arthritis, dermatitis

A new series of HAPs as anti-HBV agents targeting at capsid assembly.

PubMed

Yang, Xiu-yan; Xu, Xiao-qian; Guan, Hua; Wang, Li-li; Wu, Qin; Zhao, Guo-ming; Li, Song

2014-09-01

A series of novel Heteroaryldihydropyrimidines (HAPs) derivatives were designed and synthesized as potent inhibitors of HBV capsid assembly. These compounds were prepared from efforts to optimize an earlier series of HAPs, and compounds Mo1, Mo7, Mo8, Mo10, Mo12, and Mo13 demonstrated potent inhibition of HBV DNA replication at submicromolar range. Copyright © 2014. Published by Elsevier Ltd.

Classification of nervous system withdrawn and approved drugs with ToxPrint features via machine learning strategies.

PubMed

Onay, Aytun; Onay, Melih; Abul, Osman

2017-04-01

Early-phase virtual screening of candidate drug molecules plays a key role in pharmaceutical industry from data mining and machine learning to prevent adverse effects of the drugs. Computational classification methods can distinguish approved drugs from withdrawn ones. We focused on 6 data sets including maximum 110 approved and 110 withdrawn drugs for all and nervous system diseases to distinguish approved drugs from withdrawn ones. In this study, we used support vector machines (SVMs) and ensemble methods (EMs) such as boosted and bagged trees to classify drugs into approved and withdrawn categories. Also, we used CORINA Symphony program to identify Toxprint chemotypes including over 700 predefined chemotypes for determination of risk and safety assesment of candidate drug molecules. In addition, we studied nervous system withdrawn drugs to determine the key fragments with The ParMol package including gSpan algorithm. According to our results, the descriptors named as the number of total chemotypes and bond CN_amine_aliphatic_generic were more significant descriptors. The developed Medium Gaussian SVM model reached 78% prediction accuracy on test set for drug data set including all disease. Here, bagged tree and linear SVM models showed 89% of accuracies for phycholeptics and psychoanaleptics drugs. A set of discriminative fragments in nervous system withdrawn drug (NSWD) data sets was obtained. These fragments responsible for the drugs removed from market were benzene, toluene, N,N-dimethylethylamine, crotylamine, 5-methyl-2,4-heptadiene, octatriene and carbonyl group. This paper covers the development of computational classification methods to distinguish approved drugs from withdrawn ones. In addition, the results of this study indicated the identification of discriminative fragments is of significance to design a new nervous system approved drugs with interpretation of the structures of the NSWDs. Copyright © 2017 Elsevier B.V. All rights reserved.

Airborne measurements of isoprene and monoterpene emissions from southeastern U.S. forests.

PubMed

Yu, Haofei; Guenther, Alex; Gu, Dasa; Warneke, Carsten; Geron, Chris; Goldstein, Allen; Graus, Martin; Karl, Thomas; Kaser, Lisa; Misztal, Pawel; Yuan, Bin

2017-10-01

Isoprene and monoterpene emission rates are essential inputs for atmospheric chemistry models that simulate atmospheric oxidant and particle distributions. Process studies of the biochemical and physiological mechanisms controlling these emissions are advancing our understanding and the accuracy of model predictions but efforts to quantify regional emissions have been limited by a lack of constraints on regional distributions of ecosystem emission capacities. We used an airborne wavelet-based eddy covariance measurement technique to characterize isoprene and monoterpene fluxes with high spatial resolution during the 2013 SAS (Southeast Atmosphere Study) in the southeastern United States. The fluxes measured by direct eddy covariance were comparable to emissions independently estimated using an indirect inverse modeling approach. Isoprene emission factors based on the aircraft wavelet flux estimates for high isoprene chemotypes (e.g., oaks) were similar to the MEGAN2.1 biogenic emission model estimates for landscapes dominated by oaks. Aircraft flux measurement estimates for landscapes with fewer isoprene emitting trees (e.g., pine plantations), were about a factor of two lower than MEGAN2.1 model estimates. The tendency for high isoprene emitters in these landscapes to occur in the shaded understory, where light dependent isoprene emissions are diminished, may explain the lower than expected emissions. This result demonstrates the importance of accurately representing the vertical profile of isoprene emitting biomass in biogenic emission models. Airborne measurement-based emission factors for high monoterpene chemotypes agreed with MEGAN2.1 in landscapes dominated by pine (high monoterpene chemotype) trees but were more than a factor of three higher than model estimates for landscapes dominated by oak (relatively low monoterpene emitting) trees. This results suggests that unaccounted processes, such as floral emissions or light dependent monoterpene emissions, or vegetation other than high monoterpene emitting trees may be an important source of monoterpene emissions in those landscapes and should be identified and included in biogenic emission models. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemometric Profile of Root Extracts of Rhodiola imbricata Edgew. with Hyphenated Gas Chromatography Mass Spectrometric Technique

PubMed Central

Tayade, Amol B.; Dhar, Priyanka; Kumar, Jatinder; Sharma, Manu; Chauhan, Rajinder S.; Chaurasia, Om P.; Srivastava, Ravi B.

2013-01-01

Rhodiola imbricata Edgew. (Rose root or Arctic root or Golden root or Shrolo), belonging to the family Crassulaceae, is an important food crop and medicinal plant in the Indian trans-Himalayan cold desert. Chemometric profile of the n-hexane, chloroform, dichloroethane, ethyl acetate, methanol, and 60% ethanol root extracts of R. imbricata were performed by hyphenated gas chromatography mass spectrometry (GC/MS) technique. GC/MS analysis was carried out using Thermo Finnigan PolarisQ Ion Trap GC/MS MS system comprising of an AS2000 liquid autosampler. Interpretation on mass spectrum of GC/MS was done using the NIST/EPA/NIH Mass Spectral Database, with NIST MS search program v.2.0g. Chemometric profile of root extracts revealed the presence of 63 phyto-chemotypes, among them, 1-pentacosanol; stigmast-5-en-3-ol, (3β,24S); 1-teracosanol; 1-henteracontanol; 17-pentatriacontene; 13-tetradecen-1-ol acetate; methyl tri-butyl ammonium chloride; bis(2-ethylhexyl) phthalate; 7,8-dimethylbenzocyclooctene; ethyl linoleate; 3-methoxy-5-methylphenol; hexadecanoic acid; camphor; 1,3-dimethoxybenzene; thujone; 1,3-benzenediol, 5-pentadecyl; benzenemethanol, 3-hydroxy, 5-methoxy; cholest-4-ene-3,6-dione; dodecanoic acid, 3-hydroxy; octadecane, 1-chloro; ethanone, 1-(4-hydroxyphenyl); α-tocopherol; ascaridole; campesterol; 1-dotriacontane; heptadecane, 9-hexyl were found to be present in major amount. Eventually, in the present study we have found phytosterols, terpenoids, fatty acids, fatty acid esters, alkyl halides, phenols, alcohols, ethers, alkanes, and alkenes as the major group of phyto-chemotypes in the different root extracts of R. imbricata. All these compounds identified by GC/MS analysis were further investigated for their biological activities and it was found that they possess a diverse range of positive pharmacological actions. In future, isolation of individual phyto-chemotypes and subjecting them to biological activity will definitely prove fruitful results in designing a novel drug. PMID:23326358

Chemical composition and antioxidant capacities of phytococktail extracts from trans-Himalayan cold desert

PubMed Central

2013-01-01

Background Himalayan plants are widely used in traditional system of medicine both as prophylactics and therapeutics for high altitude maladies. Our aim was to evaluate the antioxidant capacities and bioactive compounds of methanol and n-hexane extracts of the phytococktail comprising of sea buckthorn (Hippophae rhamnoides), apricot (Prunus armeniaca) and roseroot (Rhodiola imbricata) from trans-Himalaya. Methods The 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and nitric oxide (NO) radical scavenging capacities and lipid peroxidation inhibition (LPI) property of the extracts were determined. Total antioxidant power was determined by ferric reducing/antioxidant power (FRAP) assay. Total polyphenol, flavonoid, flavonol, proanthocyanidin and carotenoid were also estimated for both extracts. We have identified and quantified the phyto-chemotypes present in the methanol and n-hexane extracts by hyphenated gas chromatography/mass spectrometry (GC/MS) technique. Results Antioxidant capacity assays using DPPH, ABTS, NO, LPI and FRAP exhibited analogous results where the phytococktail showed high antioxidant action. The phytococktail was also found to possess high quantity of total polyphenol, flavonoid, flavonol and carotenoid. A significant and linear correlation was found between the antioxidant capacities and bioactive principles. A total of 32 phyto-chemotypes were identified from these extracts by GC/MS chemometric fingerprinting. Major phyto-chemotypes identified by GC/MS were glycosides, phenylpropanoids and derivatives, terpenoids, alkaloids, phytosterols, fatty acids and esters, alkaloids and derivatives, organic acid esters and aromatic ethers with positive biological and pharmacological actions. Conclusion The phytococktail extracts were found to contain considerable amount of diverse bioactive compounds with high antioxidant capacities. The presence of hydrophilic and lipophilic antioxidants in the phytococktail could have contributed to the higher antioxidant values. Hence, the phytococktail could be used as natural source of antioxidants to ameliorate disorders associated with oxidative stress. PMID:24098968

Using physics-based pose predictions and free energy perturbation calculations to predict binding poses and relative binding affinities for FXR ligands in the D3R Grand Challenge 2

NASA Astrophysics Data System (ADS)

Athanasiou, Christina; Vasilakaki, Sofia; Dellis, Dimitris; Cournia, Zoe

2018-01-01

Computer-aided drug design has become an integral part of drug discovery and development in the pharmaceutical and biotechnology industry, and is nowadays extensively used in the lead identification and lead optimization phases. The drug design data resource (D3R) organizes challenges against blinded experimental data to prospectively test computational methodologies as an opportunity for improved methods and algorithms to emerge. We participated in Grand Challenge 2 to predict the crystallographic poses of 36 Farnesoid X Receptor (FXR)-bound ligands and the relative binding affinities for two designated subsets of 18 and 15 FXR-bound ligands. Here, we present our methodology for pose and affinity predictions and its evaluation after the release of the experimental data. For predicting the crystallographic poses, we used docking and physics-based pose prediction methods guided by the binding poses of native ligands. For FXR ligands with known chemotypes in the PDB, we accurately predicted their binding modes, while for those with unknown chemotypes the predictions were more challenging. Our group ranked #1st (based on the median RMSD) out of 46 groups, which submitted complete entries for the binding pose prediction challenge. For the relative binding affinity prediction challenge, we performed free energy perturbation (FEP) calculations coupled with molecular dynamics (MD) simulations. FEP/MD calculations displayed a high success rate in identifying compounds with better or worse binding affinity than the reference (parent) compound. Our studies suggest that when ligands with chemical precedent are available in the literature, binding pose predictions using docking and physics-based methods are reliable; however, predictions are challenging for ligands with completely unknown chemotypes. We also show that FEP/MD calculations hold predictive value and can nowadays be used in a high throughput mode in a lead optimization project provided that crystal structures of sufficiently high quality are available.

Airborne measurements of isoprene and monoterpene emissions from southeastern U.S. forests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Haofei; Guenther, Alex; Gu, Dasa

Isoprene and monoterpene emission rates are essential inputs for atmospheric chemistry models that simulate atmospheric oxidant and particle distributions. Process studies of the biochemical and physiological mechanisms controlling these emissions are advancing our understanding and the accuracy of model predictions but efforts to quantify regional emissions have been limited by a lack of constraints on regional distributions of ecosystem emission capacities. We used an airborne wavelet-based eddy covariance measurement technique to characterize isoprene and monoterpene fluxes with high spatial resolution during the 2013 SAS (Southeast Atmosphere Study) in the southeastern United States. The fluxes measured by direct eddy covariance weremore » comparable to emissions independently estimated using an indirect inverse modeling approach. Isoprene emission factors based on the aircraft wavelet flux estimates for high isoprene chemotypes (e.g., oaks) were similar to the MEGAN2.1 biogenic emission model estimates for landscapes dominated by oaks. Aircraft flux measurement estimates for landscapes with fewer isoprene emitting trees (e.g., pine plantations), were about a factor of two lower than MEGAN2.1 model estimates. The tendency for high isoprene emitters in these landscapes to occur in the shaded understory, where light dependent isoprene emissions are diminished, may explain the lower than expected emissions. This result demonstrates the importance of accurately representing the vertical profile of isoprene emitting biomass in biogenic emission models. Airborne measurement-based emission factors for high monoterpene chemotypes agreed with MEGAN2.1 in landscapes dominated by pine (high monoterpene chemotype) trees but were more than a factor of three higher than model estimates for landscapes dominated by oak (relatively low monoterpene emitting) trees. This results suggests that unaccounted processes, such as floral emissions or light dependent monoterpene emissions, or vegetation other than high monoterpene emitting trees may be an important source of monoterpene emissions in those landscapes and should be identified and included in biogenic emission models.« less

Effect of Origanum chemotypes on broiler intestinal bacteria.

PubMed

Betancourt, Liliana; Rodriguez, Fernando; Phandanouvong, Vienvilay; Ariza-Nieto, Claudia; Hume, Michael; Nisbet, David; Afanador-Téllez, German; Van Kley, Alexandra Martynova; Nalian, Armen

2014-10-01

Essential oils have been proposed as alternatives to antibiotic use in food animal production. This study evaluated 3 chemotypes of the Origanum genus, containing varying amounts of secondary metabolites carvacrol, thymol, and sabinene, in the broiler chicken diet. Aerial parts of Origanum vulgare L. (OL), O. vulgare L. ssp. hirtum (OH), and O. majorana (OM) were collected from a greenhouse located in the high altitude Sabana de Bogotá (Savanna of Bogotá) and O. vulgare L. ssp. hirtum (OG) produced and ground in Greece. Oregano essential oils (OEO) from these plants were obtained by steam distillation and analyzed by gas chromatography coupled to a mass spectrometer. Six treatments were evaluated: 200 mg/kg of OEO from OH, OL, and OM, 50 mg/kg of OEO from OG, 500 mg/kg of chlortetracycline, and without additives. Broiler chicks were maintained at 2,600 m above sea level, placed in brooder cages under a completely randomized design. Template DNA was isolated from duodenal, jejunal, ileal, and cecal contents in each group and bacterial 16S rDNA patterns were analyzed by denaturing gradient gel electrophoresis. Dendrograms of denaturing gradient gel electrophoresis band patterns revealed 2 main clusters, OEO-treated chicks and nontreated control chicks, in each intestinal segment. Band patterns from different gut compartments revealed major bacterial population shifts in the foregut (duodenum, jejunum, and ileum) compared with the hindgut (cecum and colon) at all ages evaluated (P < 0.05). The OEO groups showed less shift (62.7% similarity coefficient) between these 2 compartments versus the control groups (53.7% similarity coefficient). A reduction of 59% in mortality from ascites was seen in additive-supplemented groups compared with the control group. This study represents the first work to evaluate the effects of the 3 main chemotypes of Origanum genus in broilers. ©2014 Poultry Science Association Inc.

Enhancement of endotoxin neutralization by coupling of a C12-alkyl chain to a lactoferricin-derived peptide

PubMed Central

2004-01-01

Antibacterial peptide acylation, which mimics the structure of the natural lipopeptide polymyxin B, increases antimicrobial and endotoxin-neutralizing activities. The interaction of the lactoferricin-derived peptide LF11 and its N-terminally acylated analogue, lauryl-LF11, with different chemotypes of bacterial lipopolysaccharide (LPS Re, Ra and smooth S form) was investigated by biophysical means and was related to the peptides' biological activities. Both peptides exhibit high antibacterial activity against the three strains of Salmonella enterica differing in the LPS chemotype. Lauryl-LF11 has one order of magnitude higher activity against Re-type, but activity against Ra- and S-type bacteria is comparable with that of LF11. The alkyl derivative peptide lauryl-LF11 shows a much stronger inhibition of the LPS-induced cytokine induction in human mononuclear cells than LF11. Although peptide–LPS interaction is essentially of electrostatic nature, the lauryl-modified peptide displays a strong hydrophobic component. Such a feature might then explain the fact that saturation of the peptide binding takes place at a much lower peptide/LPS ratio for LF11 than for lauryl-LF11, and that an overcompensation of the negative LPS backbone charges is observed for lauryl-LF11. The influence of LF11 on the gel-to-liquid-crystalline phase-transition of LPS is negligible for LPS Re, but clearly fluidizing for LPS Ra. In contrast, lauryl-LF11 causes a cholesterol-like effect in the two chemotypes, fluidizing in the gel and rigidifying of the hydrocarbon chains in the liquid-crystalline phase. Both peptides convert the mixed unilamellar/non-lamellar aggregate structure of lipid A, the ‘endotoxic principle’ of LPS, into a multilamellar one. These data contribute to the understanding of the mechanisms of the peptide-mediated neutralization of endotoxin and effect of lipid modification of peptides. PMID:15344905

Study of Fungal Colonization of Wheat Kernels in Syria with a Focus on Fusarium Species

PubMed Central

Alkadri, Dima; Nipoti, Paola; Döll, Katharina; Karlovsky, Petr; Prodi, Antonio; Pisi, Annamaria

2013-01-01

Wheat is one of the main crops in Mediterranean countries, and its cultivation has an important role in the Syrian economy. In Syria, Fusarium head blight (FHB) has not been reported so far. Mycological analysis of 48 samples of wheat kernels collected from cultivation areas with different climatic conditions were performed in 2009 and 2010. Fungal isolates were identified at the genus level morphologically; Fusarium species were characterized morphologically and by species-specific PCR. The most frequent fungal genera found were Alternaria spp. and Cladosporium spp., with frequencies of 24.7% and 8.1%, respectively, while the frequency of Fusarium spp. was 1.5% of kernels. Most frequent Fusarium species were F. tricinctum (30% of all Fusarium isolates), F. culmorum (18%), F. equiseti (14%) and F. graminearum (13%). The mycotoxin production potential of selected Fusarium isolates was assessed by HPLC-MS analysis of rice cultures; chemotyping by PCR was carried out for comparison. All six F. graminearum strains tested produced small amounts (<3 mg/kg) of nivalenol (NIV). All ten F. culmorum strains tested produced large amounts of trichothecenes (>100 mg/kg); four strains produced NIV and six strains produced deoxynivalenol (DON) and 3-acetyl-deoxynivalenol (3Ac-DON). PCR chemotyping lead to an oversimplified picture, because all 3Ac-DON chemotype strains produced more DON than 3Ac-DON; furthermore, the strongest NIV producers produced significant amounts of DON. All tested strains of F. culmorum, F. graminearum, F. pseudograminearum (two strains) and most F. equiseti strains (five of six strains) produced zearalenone. Grains of durum wheat were more frequently colonized by Fusarium spp. than grains of soft wheat. Incidence of Fusarium spp. in irrigated fields was higher than in rainfed fields. The incidence of Fusarium strains producing mycotoxins raises concerns about the risk of Fusarium head blight to Syria and its consequences for public health. PMID:23493058

Design and synthesis of potent, orally-active DGAT-1 inhibitors containing a dioxino[2,3-d]pyrimidine core.

PubMed

Dow, Robert L; Andrews, Melissa; Aspnes, Gary E; Balan, Gayatri; Michael Gibbs, E; Guzman-Perez, Angel; Karki, Kapil; Laperle, Jennifer L; Li, Jian-Cheng; Litchfield, John; Munchhof, Michael J; Perreault, Christian; Patel, Leena

2011-10-15

A novel series of potent DGAT-1 inhibitors was developed originating from the lactam-based clinical candidate PF-04620110. Incorporation of a dioxino[2,3-d]pyrimidine-based core afforded good alignment of pharmacophore features and resulted in improved passive permeability. Development of an efficient, homochiral synthesis of these targets facilitated confirmation of predictions regarding the stereochemical-dependence of DGAT-1 inhibition for this series. Compound 10 was shown to be a potent inhibitor of human DGAT-1 (10 nM) and to suppress triglyceride synthesis at oral doses of <3mg/kg. Copyright © 2011 Elsevier Ltd. All rights reserved.

Structure-Based Design of Novel Dihydroalkoxybenzyloxopyrimidine Derivatives as Potent Nonnucleoside Inhibitors of the Human Immunodeficiency Virus Reverse Transcriptase

PubMed Central

Sudbeck, Elise A.; Mao, Chen; Vig, Rakesh; Venkatachalam, T. K.; Tuel-Ahlgren, Lisa; Uckun, Fatih M.

1998-01-01

Two highly potent dihydroalkoxybenzyloxopyrimidine (DABO) derivatives targeting the nonnucleoside inhibitor (NNI) binding site of human immunodeficiency virus (HIV) reverse transcriptase (RT) have been designed based on the structure of the NNI binding pocket and tested for anti-HIV activity. Our lead DABO derivative, 5-isopropyl-2-[(methylthiomethyl)thio]-6-(benzyl)-pyrimidin-4-(1H)-one, elicited potent inhibitory activity against purified recombinant HIV RT and abrogated HIV replication in peripheral blood mononuclear cells at nanomolar concentrations (50% inhibitory concentration, <1 nM) but showed no detectable cytotoxicity at concentrations as high as 100 μM. PMID:9835518

Systemic RNAi-mediated Gene Silencing in Nonhuman Primate and Rodent Myeloid Cells

PubMed Central

Novobrantseva, Tatiana I; Borodovsky, Anna; Wong, Jamie; Klebanov, Boris; Zafari, Mohammad; Yucius, Kristina; Querbes, William; Ge, Pei; Ruda, Vera M; Milstein, Stuart; Speciner, Lauren; Duncan, Rick; Barros, Scott; Basha, Genc; Cullis, Pieter; Akinc, Akin; Donahoe, Jessica S; Narayanannair Jayaprakash, K; Jayaraman, Muthusamy; Bogorad, Roman L; Love, Kevin; Whitehead, Katie; Levins, Chris; Manoharan, Muthiah; Swirski, Filip K; Weissleder, Ralph; Langer, Robert; Anderson, Daniel G; de Fougerolles, Antonin; Nahrendorf, Matthias; Koteliansky, Victor

2012-01-01

Leukocytes are central regulators of inflammation and the target cells of therapies for key diseases, including autoimmune, cardiovascular, and malignant disorders. Efficient in vivo delivery of small interfering RNA (siRNA) to immune cells could thus enable novel treatment strategies with broad applicability. In this report, we develop systemic delivery methods of siRNA encapsulated in lipid nanoparticles (LNP) for durable and potent in vivo RNA interference (RNAi)-mediated silencing in myeloid cells. This work provides the first demonstration of siRNA-mediated silencing in myeloid cell types of nonhuman primates (NHPs) and establishes the feasibility of targeting multiple gene targets in rodent myeloid cells. The therapeutic potential of these formulations was demonstrated using siRNA targeting tumor necrosis factor-α (TNFα) which induced substantial attenuation of disease progression comparable to a potent antibody treatment in a mouse model of rheumatoid arthritis (RA). In summary, we demonstrate a broadly applicable and therapeutically relevant platform for silencing disease genes in immune cells. PMID:23344621

Fragment-based approaches to the discovery of kinase inhibitors.

PubMed

Mortenson, Paul N; Berdini, Valerio; O'Reilly, Marc

2014-01-01

Protein kinases are one of the most important families of drug targets, and aberrant kinase activity has been linked to a large number of disease areas. Although eminently targetable using small molecules, kinases present a number of challenges as drug targets, not least obtaining selectivity across such a large and relatively closely related target family. Fragment-based drug discovery involves screening simple, low-molecular weight compounds to generate initial hits against a target. These hits are then optimized to more potent compounds via medicinal chemistry, usually facilitated by structural biology. Here, we will present a number of recent examples of fragment-based approaches to the discovery of kinase inhibitors, detailing the construction of fragment-screening libraries, the identification and validation of fragment hits, and their optimization into potent and selective lead compounds. The advantages of fragment-based methodologies will be discussed, along with some of the challenges associated with using this route. Finally, we will present a number of key lessons derived both from our own experience running fragment screens against kinases and from a large number of published studies.

Gene silencing in Tribolium castaneum as a tool for the targeted identification of candidate RNAi targets in crop pests.

PubMed

Knorr, Eileen; Fishilevich, Elane; Tenbusch, Linda; Frey, Meghan L F; Rangasamy, Murugesan; Billion, Andre; Worden, Sarah E; Gandra, Premchand; Arora, Kanika; Lo, Wendy; Schulenberg, Greg; Valverde-Garcia, Pablo; Vilcinskas, Andreas; Narva, Kenneth E

2018-02-01

RNAi shows potential as an agricultural technology for insect control, yet, a relatively low number of robust lethal RNAi targets have been demonstrated to control insects of agricultural interest. In the current study, a selection of lethal RNAi target genes from the iBeetle (Tribolium castaneum) screen were used to demonstrate efficacy of orthologous targets in the economically important coleopteran pests Diabrotica virgifera virgifera and Meligethes aeneus. Transcript orthologs of 50 selected genes were analyzed in D. v. virgifera diet-based RNAi bioassays; 21 of these RNAi targets showed mortality and 36 showed growth inhibition. Low dose injection- and diet-based dsRNA assays in T. castaneum and D. v. virgifera, respectively, enabled the identification of the four highly potent RNAi target genes: Rop, dre4, ncm, and RpII140. Maize was genetically engineered to express dsRNA directed against these prioritized candidate target genes. T 0 plants expressing Rop, dre4, or RpII140 RNA hairpins showed protection from D. v. virgifera larval feeding damage. dsRNA targeting Rop, dre4, ncm, and RpII140 in M. aeneus also caused high levels of mortality both by injection and feeding. In summary, high throughput systems for model organisms can be successfully used to identify potent RNA targets for difficult-to-work with agricultural insect pests.

Identification of anti-cancer targets of eco-friendly waste Punica granatum peel by dual reverse virtual screening and binding analysis.

PubMed

Usha, Talambedu; Goyal, Arvind Kumar; Lubna, Syed; Prashanth, Hp; Mohan, T Madhan; Pande, Veena; Middha, Sushil Kumar

2014-01-01

Punica granatum (family: Lythraceae) is mainly found in Iran, which is considered to be its primary centre of origin. Studies on pomegranate peel have revealed antioxidant, anti-inflammatory, anti- angiogenesis activities, with prevention of premature aging and reducing inflammation. In addition to this it is also useful in treating various diseases like diabetes, maintaining blood pressure and treatment of neoplasms such as prostate and breast cancer. In this study we identified anti-cancer targets of active compounds like corilagin (tannins), quercetin (flavonoids) and pseudopelletierine (alkaloids) present in pomegranate peel by employing dual reverse screening and binding analysis. The potent targets of the pomegranate peel were annotated by the PharmMapper and ReverseScreen 3D, then compared with targets identified from different Bioassay databases (NPACT and HIT's). Docking was then further employed using AutoDock pyrx and validated through discovery studio for studying molecular interactions. A number of potent anti-cancerous targets were attained from the PharmMapper server according to their fit score and from ReverseScreen 3D server according to decreasing 3D scores. The identified targets now need to be further validated through in vitro and in vivo studies.

Targeting the Cytochrome bc1 Complex of Leishmania Parasites for Discovery of Novel Drugs.

PubMed

Ortiz, Diana; Forquer, Isaac; Boitz, Jan; Soysa, Radika; Elya, Carolyn; Fulwiler, Audrey; Nilsen, Aaron; Polley, Tamsen; Riscoe, Michael K; Ullman, Buddy; Landfear, Scott M

2016-08-01

Endochin-like quinolones (ELQs) are potent and specific inhibitors of cytochrome bc1 from Plasmodium falciparum and Toxoplasma gondii and show promise for novel antiparasitic drug development. To determine whether the mitochondrial electron transport chain of Leishmania parasites could be targeted similarly for drug development, we investigated the activity of 134 structurally diverse ELQs. A cohort of ELQs was selectively toxic to amastigotes of Leishmania mexicana and L. donovani, with 50% inhibitory concentrations (IC50s) in the low micromolar range, but the structurally similar hydroxynaphthoquinone buparvaquone was by far the most potent inhibitor of electron transport, ATP production, and intracellular amastigote growth. Cytochrome bc1 is thus a promising target for novel antileishmanial drugs, and further improvements on the buparvaquone scaffold are warranted for development of enhanced therapeutics. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Targeting SYK kinase-dependent anti-apoptotic resistance pathway in B-lineage acute lymphoblastic leukaemia (ALL) cells with a potent SYK inhibitory pentapeptide mimic.

PubMed

Uckun, Fatih M; Ek, Rauf O; Jan, Shyi-Tai; Chen, Chun-Lin; Qazi, Sanjive

2010-05-01

The present study found that the pentapeptide mimic C-61, targeting the substrate binding P-site of SYK tyrosine kinase acted as a potent inducer of apoptosis in chemotherapy-resistant SYK-expressing primary leukemic B-cell precursors taken directly from relapsed B-precursor leukaemia (BPL) patients (but not SYK-deficient infant pro-B leukaemia cells), exhibited favourable pharmacokinetics in mice and non-human primates, and eradicated in vivo clonogenic leukaemia cells in severe combined immunodeficient mouse xenograft models of chemotherapy-resistant human BPL at dose levels non-toxic to mice and non-human primates. These in vitro and in vivo findings provide proof of principle for effective treatment of chemotherapy-resistant BPL by targeting SYK-dependent anti-apoptotic blast cell survival machinery with a SYK P-Site inhibitor. Further development of C-61 may provide the foundation for therapeutic innovation against chemotherapy-resistant BPL.

Nanobodies that block gating of the P2X7 ion channel ameliorate inflammation.

PubMed

Danquah, Welbeck; Meyer-Schwesinger, Catherine; Rissiek, Björn; Pinto, Carolina; Serracant-Prat, Arnau; Amadi, Miriam; Iacenda, Domenica; Knop, Jan-Hendrik; Hammel, Anna; Bergmann, Philine; Schwarz, Nicole; Assunção, Joana; Rotthier, Wendy; Haag, Friedrich; Tolosa, Eva; Bannas, Peter; Boué-Grabot, Eric; Magnus, Tim; Laeremans, Toon; Stortelers, Catelijne; Koch-Nolte, Friedrich

2016-11-23

Ion channels are desirable therapeutic targets, yet ion channel-directed drugs with high selectivity and few side effects are still needed. Unlike small-molecule inhibitors, antibodies are highly selective for target antigens but mostly fail to antagonize ion channel functions. Nanobodies-small, single-domain antibody fragments-may overcome these problems. P2X7 is a ligand-gated ion channel that, upon sensing adenosine 5'-triphosphate released by damaged cells, initiates a proinflammatory signaling cascade, including release of cytokines, such as interleukin-1β (IL-1β). To further explore its function, we generated and characterized nanobodies against mouse P2X7 that effectively blocked (13A7) or potentiated (14D5) gating of the channel. Systemic injection of nanobody 13A7 in mice blocked P2X7 on T cells and macrophages in vivo and ameliorated experimental glomerulonephritis and allergic contact dermatitis. We also generated nanobody Dano1, which specifically inhibited human P2X7. In endotoxin-treated human blood, Dano1 was 1000 times more potent in preventing IL-1β release than small-molecule P2X7 antagonists currently in clinical development. Our results show that nanobody technology can generate potent, specific therapeutics against ion channels, confirm P2X7 as a therapeutic target for inflammatory disorders, and characterize a potent new drug candidate that targets P2X7. Copyright © 2016, American Association for the Advancement of Science.

Detection of high levels of pyrrolizidine-N-oxides in the endangered plant cryptantha crassipes (Terlingua creek cat's-eye)using HPLC-ESI-MS

USDA-ARS?s Scientific Manuscript database

Chemical investigation of nine species of Cryptantha identified at least two chemotypes within the genus. It was determined that under especially harsh and dry growing conditions of the Chihuahuah desert of Texas, the N-oxides of two major pyrrolizidine alkaloids, lycopsamine and intermedine, foun...

Withaferin A effectively targets soluble vimentin in the glaucoma filtration surgical model of fibrosis.

PubMed

Bargagna-Mohan, Paola; Deokule, Sunil P; Thompson, Kyle; Wizeman, John; Srinivasan, Cidambi; Vooturi, Sunil; Kompella, Uday B; Mohan, Royce

2013-01-01

Withaferin A (WFA) is a natural product that binds to soluble forms of the type III intermediate filament (IF) vimentin. Currently, it is unknown under what pathophysiological contexts vimentin is druggable, as cytoskeltal vimentin-IFs are abundantly expressed. To investigate druggability of vimentin, we exploited rabbit Tenon's capsule fibroblast (RbTCF) cell cultures and the rabbit glaucoma filtration surgical (GFS) model of fibrosis. WFA potently caused G₀/G₁ cell cycle inhibition (IC₅₀ 25 nM) in RbTCFs, downregulating ubiquitin E3 ligase skp2 and inducing p27(Kip1) expression. Transforming growth factor (TGF)-ß-induced myofibroblast transformation caused development of cell spheroids with numerous elongated invadopodia, which WFA blocked potently by downregulating soluble vimentin and α-smooth muscle actin (SMA) expression. In the pilot proof-of-concept study using the GFS model, subconjunctival injections of a low WFA dose reduced skp2 expression in Tenon's capsule and increased p27(Kip1) expression without significant alteration to vimentin-IFs. This treatment maintains significant nanomolar WFA concentrations in anterior segment tissues that correspond to WFA's cell cycle targeting activity. A ten-fold higher WFA dose caused potent downregulation of soluble vimentin and skp2 expression, but as found in cell cultures, no further increase in p27(Kip1) expression was observed. Instead, this high WFA dose potently induced vimentin-IF disruption and downregulated α-SMA expression that mimicked WFA activity in TGF-ß-treated RbTCFs that blocked cell contractile activity at submicromolar concentrations. These findings illuminate that localized WFA injection to ocular tissues exerts pharmacological control over the skp2-p27(Kip1) pathway by targeting of soluble vimentin in a model of surgical fibrosis.

Ivermectin is a potent inhibitor of flavivirus replication specifically targeting NS3 helicase activity: new prospects for an old drug.

PubMed

Mastrangelo, Eloise; Pezzullo, Margherita; De Burghgraeve, Tine; Kaptein, Suzanne; Pastorino, Boris; Dallmeier, Kai; de Lamballerie, Xavier; Neyts, Johan; Hanson, Alicia M; Frick, David N; Bolognesi, Martino; Milani, Mario

2012-08-01

Infection with yellow fever virus (YFV), the prototypic mosquito-borne flavivirus, causes severe febrile disease with haemorrhage, multi-organ failure and a high mortality. Moreover, in recent years the Flavivirus genus has gained further attention due to re-emergence and increasing incidence of West Nile, dengue and Japanese encephalitis viruses. Potent and safe antivirals are urgently needed. Starting from the crystal structure of the NS3 helicase from Kunjin virus (an Australian variant of West Nile virus), we identified a novel, unexploited protein site that might be involved in the helicase catalytic cycle and could thus in principle be targeted for enzyme inhibition. In silico docking of a library of small molecules allowed us to identify a few selected compounds with high predicted affinity for the new site. Their activity against helicases from several flaviviruses was confirmed in in vitro helicase/enzymatic assays. The effect on the in vitro replication of flaviviruses was then evaluated. Ivermectin, a broadly used anti-helminthic drug, proved to be a highly potent inhibitor of YFV replication (EC₅₀ values in the sub-nanomolar range). Moreover, ivermectin inhibited, although less efficiently, the replication of several other flaviviruses, i.e. dengue fever, Japanese encephalitis and tick-borne encephalitis viruses. Ivermectin exerts its effect at a timepoint that coincides with the onset of intracellular viral RNA synthesis, as expected for a molecule that specifically targets the viral helicase. The well-tolerated drug ivermectin may hold great potential for treatment of YFV infections. Furthermore, structure-based optimization may result in analogues exerting potent activity against flaviviruses other than YFV.

Ivermectin is a potent inhibitor of flavivirus replication specifically targeting NS3 helicase activity: new prospects for an old drug

PubMed Central

Mastrangelo, Eloise; Pezzullo, Margherita; De Burghgraeve, Tine; Kaptein, Suzanne; Pastorino, Boris; Dallmeier, Kai; de Lamballerie, Xavier; Neyts, Johan; Hanson, Alicia M.; Frick, David N.; Bolognesi, Martino; Milani, Mario

2012-01-01

Objectives Infection with yellow fever virus (YFV), the prototypic mosquito-borne flavivirus, causes severe febrile disease with haemorrhage, multi-organ failure and a high mortality. Moreover, in recent years the Flavivirus genus has gained further attention due to re-emergence and increasing incidence of West Nile, dengue and Japanese encephalitis viruses. Potent and safe antivirals are urgently needed. Methods Starting from the crystal structure of the NS3 helicase from Kunjin virus (an Australian variant of West Nile virus), we identified a novel, unexploited protein site that might be involved in the helicase catalytic cycle and could thus in principle be targeted for enzyme inhibition. In silico docking of a library of small molecules allowed us to identify a few selected compounds with high predicted affinity for the new site. Their activity against helicases from several flaviviruses was confirmed in in vitro helicase/enzymatic assays. The effect on the in vitro replication of flaviviruses was then evaluated. Results Ivermectin, a broadly used anti-helminthic drug, proved to be a highly potent inhibitor of YFV replication (EC50 values in the sub-nanomolar range). Moreover, ivermectin inhibited, although less efficiently, the replication of several other flaviviruses, i.e. dengue fever, Japanese encephalitis and tick-borne encephalitis viruses. Ivermectin exerts its effect at a timepoint that coincides with the onset of intracellular viral RNA synthesis, as expected for a molecule that specifically targets the viral helicase. Conclusions The well-tolerated drug ivermectin may hold great potential for treatment of YFV infections. Furthermore, structure-based optimization may result in analogues exerting potent activity against flaviviruses other than YFV. PMID:22535622

Creation of a Novel Class of Potent and Selective MutT Homologue 1 (MTH1) Inhibitors Using Fragment-Based Screening and Structure-Based Drug Design.

PubMed

Rahm, Fredrik; Viklund, Jenny; Trésaugues, Lionel; Ellermann, Manuel; Giese, Anja; Ericsson, Ulrika; Forsblom, Rickard; Ginman, Tobias; Günther, Judith; Hallberg, Kenth; Lindström, Johan; Persson, Lars Boukharta; Silvander, Camilla; Talagas, Antoine; Díaz-Sáez, Laura; Fedorov, Oleg; Huber, Kilian V M; Panagakou, Ioanna; Siejka, Paulina; Gorjánácz, Mátyás; Bauser, Marcus; Andersson, Martin

2018-03-22

Recent literature has both suggested and questioned MTH1 as a novel cancer target. BAY-707 was just published as a target validation small molecule probe for assessing the effects of pharmacological inhibition of MTH1 on tumor cell survival, both in vitro and in vivo. (1) In this report, we describe the medicinal chemistry program creating BAY-707, where fragment-based methods were used to develop a series of highly potent and selective MTH1 inhibitors. Using structure-based drug design and rational medicinal chemistry approaches, the potency was increased over 10,000 times from the fragment starting point while maintaining high ligand efficiency and drug-like properties.

Optimization of a binding fragment targeting the "enlarged methionine pocket" leads to potent Trypanosoma brucei methionyl-tRNA synthetase inhibitors.

PubMed

Huang, Wenlin; Zhang, Zhongsheng; Ranade, Ranae M; Gillespie, J Robert; Barros-Álvarez, Ximena; Creason, Sharon A; Shibata, Sayaka; Verlinde, Christophe L M J; Hol, Wim G J; Buckner, Frederick S; Fan, Erkang

2017-06-15

Potent inhibitors of Trypanosoma brucei methionyl-tRNA synthetase were previously designed using a structure-guided approach. Compounds 1 and 2 were the most active compounds in the cyclic and linear linker series, respectively. To further improve cellular potency, SAR investigation of a binding fragment targeting the "enlarged methionine pocket" (EMP) was performed. The optimization led to the identification of a 6,8-dichloro-tetrahydroquinoline ring as a favorable fragment to bind the EMP. Replacement of 3,5-dichloro-benzyl group (the EMP binding fragment) of inhibitor 2 using this tetrahydroquinoline fragment resulted in compound 13, that exhibited an EC 50 of 4nM. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design and optimization of a series of 1-sulfonylpyrazolo[4,3-b]pyridines as selective c-Met inhibitors.

PubMed

Ma, Yuchi; Sun, Guangqiang; Chen, Danqi; Peng, Xia; Chen, Yue-Lei; Su, Yi; Ji, Yinchun; Liang, Jin; Wang, Xin; Chen, Lin; Ding, Jian; Xiong, Bing; Ai, Jing; Geng, Meiyu; Shen, Jingkang

2015-03-12

c-Met has emerged as an attractive target for targeted cancer therapy because of its abnormal activation in many cancer cells. To identify high potent and selective c-Met inhibitors, we started with profiling the potency and in vitro metabolic stability of a reported hit 7. By rational design, a novel sulfonylpyrazolo[4,3-b]pyridine 9 with improved DMPK properties was discovered. Further elaboration of π-π stacking interactions and solvent accessible polar moieties led to a series of highly potent and selective type I c-Met inhibitors. On the basis of in vitro and in vivo pharmacological and pharmacokinetics studies, compound 46 was selected as a preclinical candidate for further anticancer drug development.

Role of necroptosis in the pathogenesis of solid organ injury

PubMed Central

Zhao, H; Jaffer, T; Eguchi, S; Wang, Z; Linkermann, A; Ma, D

2015-01-01

Necroptosis is a type of regulated cell death dependent on the activity of receptor-interacting serine/threonine-protein (RIP) kinases. However, unlike apoptosis, it is caspase independent. Increasing evidence has implicated necroptosis in the pathogenesis of disease, including ischemic injury, neurodegeneration, viral infection and many others. Key players of the necroptosis signalling pathway are now widely recognized as therapeutic targets. Necrostatins may be developed as potent inhibitors of necroptosis, targeting the activity of RIPK1. Necrostatin-1, the first generation of necrostatins, has been shown to confer potent protective effects in different animal models. This review will summarize novel insights into the involvement of necroptosis in specific injury of different organs, and the therapeutic platform that it provides for treatment. PMID:26583318

Fragment-Based Drug Discovery in the Bromodomain and Extra-Terminal Domain Family.

PubMed

Radwan, Mostafa; Serya, Rabah

2017-08-01

Bromodomain and extra-terminal domain (BET) inhibition has emerged recently as a potential therapeutic target for the treatment of many human disorders such as atherosclerosis, inflammatory disorders, chronic obstructive pulmonary disease (COPD), some viral infections, and cancer. Since the discovery of the two potent inhibitors, I-BET762 and JQ1, different research groups have used different techniques to develop novel potent and selective inhibitors. In this review, we will be concerned with the trials that used fragment-based drug discovery (FBDD) approaches to discover or optimize BET inhibitors, also showing fragments that can be further optimized in future projects to reach novel potent BET inhibitors. © 2017 Deutsche Pharmazeutische Gesellschaft.

Design, synthesis and biological evaluation of bisthiazole-based trifluoromethyl ketone derivatives as potent HDAC inhibitors with improved cellular efficacy.

PubMed

Gong, Chao-Jun; Gao, An-Hui; Zhang, Yang-Ming; Su, Ming-Bo; Chen, Fei; Sheng, Li; Zhou, Yu-Bo; Li, Jing-Ya; Li, Jia; Nan, Fa-Jun

2016-04-13

Histone deacetylases (HDACs) are a class of epigenetic modulators with complex functions in histone post-translational modifications and are well known targets for antineoplastic drugs. We have previously developed a series of bisthiazole-based hydroxamic acids as novel potent HDAC inhibitors. In the present work, a new series of bisthiazole-based compounds with different zinc binding groups (ZBGs) have been designed and synthesized. Among them is compound 7, containing a trifluoromethyl ketone as the ZBG, which displays potent inhibitory activity towards human HDACs and improved antiproliferative activity in several cancer cell lines. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Target Residence Time-Guided Optimization on TTK Kinase Results in Inhibitors with Potent Anti-Proliferative Activity.

PubMed

Uitdehaag, Joost C M; de Man, Jos; Willemsen-Seegers, Nicole; Prinsen, Martine B W; Libouban, Marion A A; Sterrenburg, Jan Gerard; de Wit, Joeri J P; de Vetter, Judith R F; de Roos, Jeroen A D M; Buijsman, Rogier C; Zaman, Guido J R

2017-07-07

The protein kinase threonine tyrosine kinase (TTK; also known as Mps1) is a critical component of the spindle assembly checkpoint and a promising drug target for the treatment of aggressive cancers, such as triple negative breast cancer. While the first TTK inhibitors have entered clinical trials, little is known about how the inhibition of TTK with small-molecule compounds affects cellular activity. We studied the selective TTK inhibitor NTRC 0066-0, which was developed in our own laboratory, together with 11 TTK inhibitors developed by other companies, including Mps-BAY2b, BAY 1161909, BAY 1217389 (Bayer), TC-Mps1-12 (Shionogi), and MPI-0479605 (Myrexis). Parallel testing shows that the cellular activity of these TTK inhibitors correlates with their binding affinity to TTK and, more strongly, with target residence time. TTK inhibitors are therefore an example where target residence time determines activity in in vitro cellular assays. X-ray structures and thermal stability experiments reveal that the most potent compounds induce a shift of the glycine-rich loop as a result of binding to the catalytic lysine at position 553. This "lysine trap" disrupts the catalytic machinery. Based on these insights, we developed TTK inhibitors, based on a (5,6-dihydro)pyrimido[4,5-e]indolizine scaffold, with longer target residence times, which further exploit an allosteric pocket surrounding Lys553. Their binding mode is new for kinase inhibitors and can be classified as hybrid Type I/Type III. These inhibitors have very potent anti-proliferative activity that rivals classic cytotoxic therapy. Our findings will open up new avenues for more applications for TTK inhibitors in cancer treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analogs of natural aminoacyl-tRNA synthetase inhibitors clear malaria in vivo

PubMed Central

Novoa, Eva Maria; Camacho, Noelia; Tor, Anna; Wilkinson, Barrie; Moss, Steven; Marín-García, Patricia; Azcárate, Isabel G.; Bautista, José M.; Mirando, Adam C.; Francklyn, Christopher S.; Varon, Sònia; Royo, Miriam; Cortés, Alfred; Ribas de Pouplana, Lluís

2014-01-01

Malaria remains a major global health problem. Emerging resistance to existing antimalarial drugs drives the search for new antimalarials, and protein translation is a promising pathway to target. Here we explore the potential of the aminoacyl-tRNA synthetase (ARS) family as a source of antimalarial drug targets. First, a battery of known and novel ARS inhibitors was tested against Plasmodium falciparum cultures, and their activities were compared. Borrelidin, a natural inhibitor of threonyl-tRNA synthetase (ThrRS), stands out for its potent antimalarial effect. However, it also inhibits human ThrRS and is highly toxic to human cells. To circumvent this problem, we tested a library of bioengineered and semisynthetic borrelidin analogs for their antimalarial activity and toxicity. We found that some analogs effectively lose their toxicity against human cells while retaining a potent antiparasitic activity both in vitro and in vivo and cleared malaria from Plasmodium yoelii-infected mice, resulting in 100% mice survival rates. Our work identifies borrelidin analogs as potent, selective, and unexplored scaffolds that efficiently clear malaria both in vitro and in vivo. PMID:25489076

Macrophages with cellular backpacks for targeted drug delivery to the brain.

PubMed

Klyachko, Natalia L; Polak, Roberta; Haney, Matthew J; Zhao, Yuling; Gomes Neto, Reginaldo J; Hill, Michael C; Kabanov, Alexander V; Cohen, Robert E; Rubner, Michael F; Batrakova, Elena V

2017-09-01

Most potent therapeutics are unable to cross the blood-brain barrier following systemic administration, which necessitates the development of unconventional, clinically applicable drug delivery systems. With the given challenges, biologically active vehicles are crucial to accomplishing this task. We now report a new method for drug delivery that utilizes living cells as vehicles for drug carriage across the blood brain barrier. Cellular backpacks, 7-10 μm diameter polymer patches of a few hundred nanometers in thickness, are a potentially interesting approach, because they can act as drug depots that travel with the cell-carrier, without being phagocytized. Backpacks loaded with a potent antioxidant, catalase, were attached to autologous macrophages and systemically administered into mice with brain inflammation. Using inflammatory response cells enabled targeted drug transport to the inflamed brain. Furthermore, catalase-loaded backpacks demonstrated potent therapeutic effects deactivating free radicals released by activated microglia in vitro. This approach for drug carriage and release can accelerate the development of new drug formulations for all the neurodegenerative disorders. Copyright © 2017. Published by Elsevier Ltd.

Design, Synthesis and Biological Evaluation of 6-(2,6-Dichloro-3,5-dimethoxyphenyl)-4-substituted-1H-indazoles as Potent Fibroblast Growth Factor Receptor Inhibitors.

PubMed

Zhang, Zhen; Zhao, Dongmei; Dai, Yang; Cheng, Maosheng; Geng, Meiyu; Shen, Jingkang; Ma, Yuchi; Ai, Jing; Xiong, Bing

2016-10-23

Tyrosine kinase fibroblast growth factor receptor (FGFR), which is aberrant in various cancer types, is a promising target for cancer therapy. Here we reported the design, synthesis, and biological evaluation of a new series of 6-(2,6-dichloro-3,5-dimethoxyphenyl)-4-substituted-1 H -indazole derivatives as potent FGFR inhibitors. The compound 6-(2,6-dichloro-3,5-dimethoxyphenyl)- N -phenyl-1 H -indazole-4-carboxamide ( 10a ) was identified as a potent FGFR1 inhibitor, with good enzymatic inhibition. Further structure-based optimization revealed that 6-(2,6-dichloro-3,5-dimethoxyphenyl)- N -(3-(4-methylpiperazin-1-yl)phenyl)-1 H -indazole-4-carboxamide ( 13a ) is the most potent FGFR1 inhibitor in this series, with an enzyme inhibitory activity IC 50 value of about 30.2 nM.

Evaluation of anti-Zika virus activities of broad-spectrum antivirals and NIH clinical collection compounds using a cell-based, high-throughput screen assay.

PubMed

Adcock, Robert S; Chu, Yong-Kyu; Golden, Jennifer E; Chung, Dong-Hoon

2017-02-01

Recent studies have clearly underscored the association between Zika virus (ZIKV) and severe neurological diseases such as microcephaly and Guillain-Barre syndrome. Given the historical complacency surrounding this virus, however, no significant antiviral screenings have been performed to specifically target ZIKV. As a result, there is an urgent need for a validated screening method and strategy that is focused on highlighting potential anti-ZIKV inhibitors that can be further advanced via rigorous validation and optimization. To address this critical gap, we sought to test whether a cell-based assay that measures protection from the ZIKV-induced cytopathic effect could serve as a high-throughput screen assay for discovering novel anti-ZIKV inhibitors. Employing this approach, we tested the anti-ZIKV activity of previously known broad-spectrum antiviral compounds and discovered several compounds (e.g., NITD008, SaliPhe, and CID 91632869) with anti-ZIKV activity. Interestingly, while GTP synthesis inhibitors (e.g., ribavirin or mycophenolic acid) were too toxic or showed no anti-ZIKV activity (EC 50  > 50 μM), ZIKV was highly susceptible to pyrimidine synthesis inhibitors (e.g., brequinar) in the assay. We amended the assay into a high-throughput screen (HTS)-compatible 384-well format and then screened the NIH Clinical Compound Collection library, which includes a total of 727 compounds organized, using an 8-point dose response format with two Zika virus strains (MR766 and PRVABC59, a recent human isolate). The screen discovered 6-azauridine and finasteride as potential anti-ZIKV inhibitors with EC 50 levels of 3.18 and 9.85 μM for MR766, respectively. We further characterized the anti-ZIKV activity of 6-azauridine and several pyrimidine synthesis inhibitors such as brequinar in various secondary assays including an antiviral spectrum test within flaviviruses and alphaviruses, Western blot (protein), real-time PCR (RNA), and plaque reduction assays (progeny virus). From these assays, we discovered that brequinar has potent anti-ZIKV activity. Our results show that a broad anti-ZIKV screen of compound libraries with our CPE-based HTS assay will reveal multiple chemotypes that could be pursued as lead compounds for therapies to treat ZIKV-associated diseases or as molecular probes to study the biology of the ZIKV replication mechanism. Copyright © 2016 Elsevier B.V. All rights reserved.

Post-translational modifications of transthyretin affect the triiodonine-binding potential

PubMed Central

Henze, Andrea; Homann, Thomas; Serteser, Mustafa; Can, Ozge; Sezgin, Ozlem; Coskun, Abdurrahman; Unsal, Ibrahim; Schweigert, Florian J; Ozpinar, Aysel

2015-01-01

Transthyretin (TTR) is a visceral protein, which facilitates the transport of thyroid hormones in blood and cerebrospinal fluid. The homotetrameric structure of TTR enables the simultaneous binding of two thyroid hormones per molecule. Each TTR subunit provides a single cysteine residue (Cys10), which is frequently affected by oxidative post-translational modifications. As Cys10 is part of the thyroid hormone-binding channel within the TTR molecule, PTM of Cys10 may influence the binding of thyroid hormones. Therefore, we analysed the effects of Cys10 modification with sulphonic acid, cysteine, cysteinylglycine and glutathione on binding of triiodothyronine (T3) by molecular modelling. Furthermore, we determined the PTM pattern of TTR in serum of patients with thyroid disease by immunoprecipitation and mass spectrometry to evaluate this association in vivo. The in silico assays demonstrated that oxidative PTM of TTR resulted in substantial reorganization of the intramolecular interactions and also affected the binding of T3 in a chemotype- and site-specific manner with S-glutathionylation as the most potent modulator of T3 binding. These findings were supported by the in vivo results, which indicated thyroid function-specific patterns of TTR with a substantial decrease in S-sulphonated, S-cysteinylglycinated and S-glutathionylated TTR in hypothyroid patients. In conclusion, this study provides evidence that oxidative modifications of Cys10 seem to affect binding of T3 to TTR probably because of the introduction of a sterical hindrance and induction of conformational changes. As oxidative modifications can be dynamically regulated, this may represent a sensitive mechanism to adjust thyroid hormone availability. PMID:25311081

Cross Talk between Nucleotide Synthesis Pathways with Cellular Immunity in Constraining Hepatitis E Virus Replication

PubMed Central

Wang, Yijin; Wang, Wenshi; Xu, Lei; Zhou, Xinying; Shokrollahi, Ehsan; Felczak, Krzysztof; van der Laan, Luc J. W.; Pankiewicz, Krzysztof W.; Sprengers, Dave; Raat, Nicolaas J. H.; Metselaar, Herold J.; Peppelenbosch, Maikel P.

2016-01-01

Viruses are solely dependent on host cells to propagate; therefore, understanding virus-host interaction is important for antiviral drug development. Since de novo nucleotide biosynthesis is essentially required for both host cell metabolism and viral replication, specific catalytic enzymes of these pathways have been explored as potential antiviral targets. In this study, we investigated the role of different enzymatic cascades of nucleotide biosynthesis in hepatitis E virus (HEV) replication. By profiling various pharmacological inhibitors of nucleotide biosynthesis, we found that targeting the early steps of the purine biosynthesis pathway led to the enhancement of HEV replication, whereas targeting the later step resulted in potent antiviral activity via the depletion of purine nucleotide. Furthermore, the inhibition of the pyrimidine pathway resulted in potent anti-HEV activity. Interestingly, all of these inhibitors with anti-HEV activity concurrently triggered the induction of antiviral interferon-stimulated genes (ISGs). Although ISGs are commonly induced by interferons via the JAK-STAT pathway, their induction by nucleotide synthesis inhibitors is completely independent of this classical mechanism. In conclusion, this study revealed an unconventional novel mechanism of cross talk between nucleotide biosynthesis pathways and cellular antiviral immunity in constraining HEV infection. Targeting particular enzymes in nucleotide biosynthesis represents a viable option for antiviral drug development against HEV. HEV is the most common cause of acute viral hepatitis worldwide and is also associated with chronic hepatitis, especially in immunocompromised patients. Although often an acute and self-limiting infection in the general population, HEV can cause severe morbidity and mortality in certain patients, a problem compounded by the lack of FDA-approved anti-HEV medication available. In this study, we have investigated the role of the nucleotide synthesis pathway in HEV infection and its potential for antiviral drug development. We show that targeting the later but not the early steps of the purine synthesis pathway exerts strong anti-HEV activity. In particular, IMP dehydrogenase (IMPDH) is the most important anti-HEV target of this cascade. Importantly, the clinically used IMPDH inhibitors, including mycophenolic acid and ribavirin, have potent anti-HEV activity. Furthermore, targeting the pyrimidine synthesis pathway also exerts potent antiviral activity against HEV. Interestingly, antiviral effects of nucleotide synthesis pathway inhibitors appear to depend on the medication-induced transcription of antiviral interferon-stimulated genes. Thus, this study reveals an unconventional novel mechanism as to how nucleotide synthesis pathway inhibitors can counteract HEV replication. PMID:26926637

Chemical analysis of essential oils from different parts of Ferula communis L. growing in central Italy.

PubMed

Maggi, Filippo; Papa, Fabrizio; Dall'Acqua, Stefano; Nicoletti, Marcello

2016-01-01

Ferula communis is a showy herbaceous plant typical of the Mediterranean area where it is used as a traditional medicine. The plant is a source of bioactive compounds such as daucane sesquiterpenes and prenylated coumarins. In Italy, most of phytochemical studies focused on Sardinian populations where poisonous and nonpoisonous chemotypes were found, while investigations on peninsular populations are scarce. In this work, we report the chemical characterisation of the essential oils obtained from different parts of F. communis growing in central Italy. The chemical profiles of the plant parts, as detected by GC-FID and GC-MS, were different from each other and from those reported in insular populations. Notably, α-pinene (10.5%), γ-terpinene (7.6%) and hedycariol (8.4%) were the major volatile constituents in flowers; α-pinene (55.9%), β-pinene (16.8%) and myrcene (5.9%) in fruits; β-eudesmol (12.1%), α-eudesmol (12.1%) and hedycariol (10.3%) in leaves; (E)-β-farnesene (9.5%), β-cubebene (8.2%) and (E)-caryophyllene (7.2%) in roots. The volatile profiles detected did not allow to classify the investigated central Italy population into the poisonous and nonpoisonous chemotypes previously described in Sardinia.

Discovery of novel and cardioselective diltiazem-like calcium channel blockers via virtual screening.

PubMed

Carosati, Emanuele; Budriesi, Roberta; Ioan, Pierfranco; Ugenti, Maria P; Frosini, Maria; Fusi, Fabio; Corda, Gaetano; Cosimelli, Barbara; Spinelli, Domenico; Chiarini, Alberto; Cruciani, Gabriele

2008-09-25

With the effort to discover new chemotypes blocking L-type calcium channels (LTCCs), ligand-based virtual screening was applied with a specific interest toward the diltiazem binding site. Roughly 50000 commercially available compounds served as a database for screening. The filtering through predicted pharmacokinetic properties and structural requirements reduced the initial database to a few compounds for which the similarity was calculated toward two template molecules, diltiazem and 4-chloro-Ncyclopropyl- N-(4-piperidinyl)benzene-sulfonamide, the most interesting hit of a previous screening experiment. For 18 compounds, inotropic and chronotropic activity as well as the vasorelaxant effect on guinea pig were studied "in vitro", and for the most promising, binding studies to the diltiazem site were carried out. The procedure yielded several hits, confirming in silico techniques to be useful for finding new chemotypes. In particular, N-[2-(dimethylamino)ethyl]-3-hydroxy-2-naphthamide, N,Ndimethyl- N'-(2-pyridin-3-ylquinolin-4-yl)ethane-1,2-diamine, 2-[(4-chlorophenyl)(pyridin-2-yl)methoxy]- N,N-dimethylethanamine (carbinoxamine), and 7-[2-(diethylamino)ethoxy]-2H-chromen-2-one revealed interesting activity and binding to the benzothiazepine site.

Cannabis cultivation: Methodological issues for obtaining medical-grade product.

PubMed

Chandra, Suman; Lata, Hemant; ElSohly, Mahmoud A; Walker, Larry A; Potter, David

2017-05-01

As studies continue to reveal favorable findings for the use of cannabidiol in the management of childhood epilepsy syndromes and other disorders, best practices for the large-scale production of Cannabis are needed for timely product development and research purposes. The processes of two institutions with extensive experience in producing large-scale cannabidiol chemotype Cannabis crops-GW Pharmaceuticals and the University of Mississippi-are described, including breeding, indoor and outdoor growing, harvesting, and extraction methods. Such practices have yielded desirable outcomes in Cannabis breeding and production: GW Pharmaceuticals has a collection of chemotypes dominant in any one of eight cannabinoids, two of which-cannabidiol and cannabidivarin-are supporting epilepsy clinical trial research, whereas in addition to a germplasm bank of high-THC, high-CBD, and intermediate type cannabis varieties, the team at University of Mississippi has established an in vitro propagation protocol for cannabis with no detectable variations in morphologic, physiologic, biochemical, and genetic profiles as compared to the mother plants. Improvements in phytocannabinoid yields and growing efficiency are expected as research continues at these institutions. This article is part of a Special Issue entitled "Cannabinoids and Epilepsy". Copyright © 2016. Published by Elsevier Inc.

Essential Oil from Piper aduncum: Chemical Analysis, Antimicrobial Assessment, and Literature Review

PubMed Central

Monzote, Lianet; Scull, Ramón; Cos, Paul; Setzer, William N.

2017-01-01

Background: The challenge in antimicrobial chemotherapy is to find safe and selective agents with potency that will not be compromised by previously developed resistance. Terrestrial plants could provide new leads to antibacterial, antifungal, or antiprotozoal activity. Methods: The essential oil (EO) of Piper aduncum L. (Piperaceae) from Cuba was analyzed by gas chromatography—mass spectrometry (GC-MS). A cluster analysis of P. aduncum EO compositions reported in the literature was carried out. The EO was screened against a panel of microorganisms (bacteria, fungi, parasitic protozoa) as well as for cytotoxicity against human cells. In addition, a review of scientific literature and a bibliometric study was also conducted. Results: A total of 90 compounds were identified in the EO, of which camphor (17.1%), viridiflorol (14.5%), and piperitone (23.7%) were the main components. The cluster analysis revealed at least nine different chemotypes. The EO did not show notable activity against bacteria or fungi, but was active against parasitic protozoa. Conclusions: The results from this study indicate P. aduncum from Cuba is a unique chemotype, support the importance of P. aduncum EOs as medicines, and demonstrate the promise of Cuban P. aduncum EO as a chemotherapeutic agent against parasitic protozoal infections. PMID:28930264

Essential Oil from Piper aduncum: Chemical Analysis, Antimicrobial Assessment, and Literature Review.

PubMed

Monzote, Lianet; Scull, Ramón; Cos, Paul; Setzer, William N

2017-07-02

Background: The challenge in antimicrobial chemotherapy is to find safe and selective agents with potency that will not be compromised by previously developed resistance. Terrestrial plants could provide new leads to antibacterial, antifungal, or antiprotozoal activity. Methods: The essential oil (EO) of Piper aduncum L. (Piperaceae) from Cuba was analyzed by gas chromatography-mass spectrometry (GC-MS). A cluster analysis of P. aduncum EO compositions reported in the literature was carried out. The EO was screened against a panel of microorganisms (bacteria, fungi, parasitic protozoa) as well as for cytotoxicity against human cells. In addition, a review of scientific literature and a bibliometric study was also conducted. Results: A total of 90 compounds were identified in the EO, of which camphor (17.1%), viridiflorol (14.5%), and piperitone (23.7%) were the main components. The cluster analysis revealed at least nine different chemotypes. The EO did not show notable activity against bacteria or fungi, but was active against parasitic protozoa. Conclusions: The results from this study indicate P. aduncum from Cuba is a unique chemotype, support the importance of P. aduncum EOs as medicines, and demonstrate the promise of Cuban P. aduncum EO as a chemotherapeutic agent against parasitic protozoal infections.

Essential oil variation among natural populations of Lavandula multifida L. (Lamiaceae).

PubMed

Chograni, Hnia; Zaouali, Yosr; Rajeb, Chayma; Boussaid, Mohamed

2010-04-01

Volatiles from twelve wild Tunisian populations of Lavandula multifida L. growing in different bioclimatic zones were assessed by GC (RI) and GC/MS. Thirty-six constituents, representing 83.48% of the total oil were identified. The major components at the species level were carvacrol (31.81%), beta-bisabolene (14.89%), and acrylic acid dodecyl ester (11.43%). These volatiles, together with alpha-pinene, were also the main compounds discriminating the populations. According to these dominant compounds, one chemotype was revealed, a carvacrol/beta-bisabolene/acrylic acid dodecyl ester chemotype. However, a significant variation among the populations was observed for the majority of the constituents. A high chemical-population structure, estimated both by principal component analysis (PCA) and unweighted pair group method with averaging (UPGMA) cluster analysis based on Euclidean distances, was observed. Both methods allowed separation of the populations in three groups defined rather by minor than by major compounds. The population groups were not strictly concordant with their bioclimatic or geographic location. Conservation strategies should concern all populations, because of their low size and their high level of destruction. Populations exhibiting particular compounds other than the major ones should be protected first.

The effect of diets supplemented with thyme essential oils and rosemary extract on the deterioration of farmed gilthead seabream (Sparus aurata) during storage on ice.

PubMed

Álvarez, A; García García, B; Jordán, M J; Martínez-Conesa, C; Hernández, M D

2012-06-01

The effect on quality were assessed for gilthead seabream fed five different diets: control (basal diet); BHT (basal diet with 200mgkg -1 of butylated hydroxytoluene); rosemary (basal diet with 600mgkg -1 of rosemary extract -Rosmarinus officinalis); carvacrol (basal diet with 500mgkg -1 of essential oil of Thymbra capitata, carvacrol chemotype); and thymol (basal diet with 500mgg -1 of essential oil of Thymus zygis, subspecies gracilis, thymol chemotype). After 18weeks of experimentation, the animals were stored on ice at 4°C for 0, 7, 14, and 21days. Physical-chemical, microbiological and sensory analyses were carried out at each sampling point to determine the degree of deterioration in the gilthead seabream. Lower indices of oxidation were observed in animals who were administered feeds supplemented with BHT, carvacrol and (to a lesser degree) rosemary. Lower bacteria counts were observed for the BHT and thymol groups, in addition to a slower deterioration in terms of sensory perception. Accordingly, the addition of natural antioxidants to the diet may have an added effect on fish quality, delaying post mortem deterioration. Copyright © 2011 Elsevier Ltd. All rights reserved.

Eugenol and methyl eugenol chemotypes of essential oil of species Ocimum gratissimum L. and Ocimum campechianum Mill. from Colombia.

PubMed

Pino Benitez, Nayive; Meléndez León, Erika M; Stashenko, Elena E

2009-10-01

Essential oils chemical constituents of leaves of O. gratissimum and O. campechianum of the Lamiaceae family, collected in Chocó of northwest Colombian, were obtained by microwave-assisted hydrodistillation and analyzed by gas chromatography coupled with mass spectrometry. A total of 33 and 37 compounds were identified in the essential oil of O. gratissimum and O. campechianum, respectively. O. gratissimum's main essential oils were eugenol (43.2%), 1,8-cineole (12.8%) and beta-selinene (9.0%); in the O. campechianum essential oil, the main components were methyl eugenol (12.0%), germacrene D (10.1%), and eugenol (9.0%). Main distribution of compounds in these essential oils are 25.0% monoterpenes hydrocarbons, 15.0% monoterpenes oxygenated, 35.0% sesquiterpenes hydrocarbons, 7.5% other oxygenated components for O. gratissimum, 33.9% sesquiterpenes hydrocarbons, and 10.7% their respective oxygenated derivates; for O. campechianum, the distribution was 10.7% monoterpenes hydrocarbons and 7.1% their respective oxygenated derivates and 3.6% phenylpropanes. According to the essential oils chemical composition of Ocimum gratissimum and O. campechianum, they are classified as eugenol and methyl eugenol chemotype, respectively.

Targeting Prostate Cancer for Gene Therapy Utilizing Lentivirus and Oncolytic VSV Virus

DTIC Science & Technology

2010-04-01

antitumoral, antivascular, and anti-HBV activities in patients with hepatocellular carcinoma . Mol T her, 2008. 16(9): p. 1637-42. 16. Ribacka, C . a nd...adenovirus targeting to TERT and RB pathway induced specific and potent anti-tumor efficacy in vitro and in vivo for hepatocellular carcinoma . Cancer

Mathematical modeling of antibody drug conjugates with the target and tubulin dynamics to predict AUC.

PubMed

Byun, Jong Hyuk; Jung, Il Hyo

2018-04-14

Antibody drug conjugates (ADCs)are one of the most recently developed chemotherapeutics to treat some types of tumor cells. They consist of monoclonal antibodies (mAbs), linkers, and potent cytotoxic drugs. Unlike common chemotherapies, ADCs combine selectively with a target at the surface of the tumor cell, and a potent cytotoxic drug (payload) effectively prevents microtubule polymerization. In this work, we construct an ADC model that considers both the target of antibodies and the receptor (tubulin) of the cytotoxic payloads. The model is simulated with brentuximab vedotin, one of ADCs, and used to investigate the pharmacokinetic (PK) characteristics of ADCs in vivo. It also predicts area under the curve (AUC) of ADCs and the payloads by identifying the half-life. The results show that dynamical behaviors fairly coincide with the observed data and half-life and capture AUC. Thus, the model can be used for estimating some parameters, fitting experimental observations, predicting AUC, and exploring various dynamical behaviors of the target and the receptor. Copyright © 2018 Elsevier Ltd. All rights reserved.

Quinolinic Carboxylic Acid Derivatives as Potential Multi-target Compounds for Neurodegeneration: Monoamine Oxidase and Cholinesterase Inhibition.

PubMed

Khan, Nehal A; Khan, Imtiaz; Abid, Syed M A; Zaib, Sumera; Ibrar, Aliya; Andleeb, Hina; Hameed, Shahid; Iqbal, Jamshed

2018-01-01

Parkinson's disease (PD), a debilitating and progressive disorder, is among the most challenging and devastating neurodegenerative diseases predominantly affecting the people over 60 years of age. To confront PD, an advanced and operational strategy is to design single chemical functionality able to control more than one target instantaneously. In this endeavor, for the exploration of new and efficient inhibitors of Parkinson's disease, we synthesized a series of quinoline carboxylic acids (3a-j) and evaluated their in vitro monoamine oxidase and cholinesterase inhibitory activities. The molecular docking and in silico studies of the most potent inhibitors were performed to identify the probable binding modes in the active site of the monoamine oxidase enzymes. Moreover, molecular properties were calculated to evaluate the druglikeness of the compounds. The biological evaluation results revealed that the tested compounds were highly potent against monoamine oxidase (A & B), 3c targeted both the isoforms of MAO with IC50 values of 0.51 ± 0.12 and 0.51 ± 0.03 µM, respectively. The tested compounds also demonstrated high and completely selective inhibitory action against acetylcholinesterase (AChE) with IC50 values ranging from 4.36 to 89.24 µM. Among the examined derivatives, 3i was recognized as the most potent inhibitor of AChE with an IC50 value of 4.36 ± 0.12 ±µM. The compounds appear to be promising inhibitors and could be used for the future development of drugs targeting neurodegenerative disorders. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Targeting Membrane-Bound Viral RNA Synthesis Reveals Potent Inhibition of Diverse Coronaviruses Including the Middle East Respiratory Syndrome Virus

PubMed Central

Bergström, Tomas; Kann, Nina; Adamiak, Beata; Hannoun, Charles; Kindler, Eveline; Jónsdóttir, Hulda R.; Muth, Doreen; Kint, Joeri; Forlenza, Maria; Müller, Marcel A.; Drosten, Christian; Thiel, Volker; Trybala, Edward

2014-01-01

Coronaviruses raise serious concerns as emerging zoonotic viruses without specific antiviral drugs available. Here we screened a collection of 16671 diverse compounds for anti-human coronavirus 229E activity and identified an inhibitor, designated K22, that specifically targets membrane-bound coronaviral RNA synthesis. K22 exerts most potent antiviral activity after virus entry during an early step of the viral life cycle. Specifically, the formation of double membrane vesicles (DMVs), a hallmark of coronavirus replication, was greatly impaired upon K22 treatment accompanied by near-complete inhibition of viral RNA synthesis. K22-resistant viruses contained substitutions in non-structural protein 6 (nsp6), a membrane-spanning integral component of the viral replication complex implicated in DMV formation, corroborating that K22 targets membrane bound viral RNA synthesis. Besides K22 resistance, the nsp6 mutants induced a reduced number of DMVs, displayed decreased specific infectivity, while RNA synthesis was not affected. Importantly, K22 inhibits a broad range of coronaviruses, including Middle East respiratory syndrome coronavirus (MERS–CoV), and efficient inhibition was achieved in primary human epithelia cultures representing the entry port of human coronavirus infection. Collectively, this study proposes an evolutionary conserved step in the life cycle of positive-stranded RNA viruses, the recruitment of cellular membranes for viral replication, as vulnerable and, most importantly, druggable target for antiviral intervention. We expect this mode of action to serve as a paradigm for the development of potent antiviral drugs to combat many animal and human virus infections. PMID:24874215

New Pyrazolopyrimidine Inhibitors of Protein Kinase D as Potent Anticancer Agents for Prostate Cancer Cells

PubMed Central

Tandon, Manuj; Johnson, James; Li, Zhihong; Xu, Shuping; Wipf, Peter; Wang, Qiming Jane

2013-01-01

The emergence of protein kinase D (PKD) as a potential therapeutic target for several diseases including cancer has triggered the search for potent, selective, and cell-permeable small molecule inhibitors. In this study, we describe the identification, in vitro characterization, structure-activity analysis, and biological evaluation of a novel PKD inhibitory scaffold exemplified by 1-naphthyl PP1 (1-NA-PP1). 1-NA-PP1 and IKK-16 were identified as pan-PKD inhibitors in a small-scale targeted kinase inhibitor library assay. Both screening hits inhibited PKD isoforms at about 100 nM and were ATP-competitive inhibitors. Analysis of several related kinases indicated that 1-NA-PP1 was highly selective for PKD as compared to IKK-16. SAR analysis showed that 1-NA-PP1 was considerably more potent and showed distinct substituent effects at the pyrazolopyrimidine core. 1-NA-PP1 was cell-active, and potently blocked prostate cancer cell proliferation by inducing G2/M arrest. It also potently blocked the migration and invasion of prostate cancer cells, demonstrating promising anticancer activities on multiple fronts. Overexpression of PKD1 or PKD3 almost completely reversed the growth arrest and the inhibition of tumor cell invasion caused by 1-NA-PP1, indicating that its anti-proliferative and anti-invasive activities were mediated through the inhibition of PKD. Interestingly, a 12-fold increase in sensitivity to 1-NA-PP1 could be achieved by engineering a gatekeeper mutation in the active site of PKD1, suggesting that 1-NA-PP1 could be paired with the analog-sensitive PKD1M659G for dissecting PKD-specific functions and signaling pathways in various biological systems. PMID:24086585

Recent advances in malaria drug discovery.

PubMed

Lanteri, Charlotte A; Johnson, Jacob D; Waters, Norman C

2007-06-01

Malaria is responsible for over 300 million clinical cases annually and claims the lives of approximately 1-2 million. With a disease that has plagued humanity throughout history, one would think that better control measures would be in place to decrease the mortality and morbidity associated with malaria. Due to malaria drug resistance, an increase in the number of clinical infections and deaths is soon likely to be observed. Therefore, there is a push to identify and introduce new drug entities for malaria treatment and prophylaxis. In an effort to develop new malaria drugs, several different approaches have been implemented. These include the use of drug combinations of either new or existing antimalarials, exploitation of natural products, identification of resistance reversal or sensitizing agents and the targeting of specific malarial enzymes. Past experience has shown that introduction of the same chemical entities, such as quinolines and antifolates, results in only limited efficacy with resistance developing rapidly within one year of introduction. New approaches to drug discovery should identify novel chemotypes which circumvent the parasite's disposition to drug resistance. This review summarizes current efforts in malaria drug discovery as uncovered in recent patent literature.

MAO inhibitors and their wider applications: a patent review.

PubMed

Carradori, Simone; Secci, Daniela; Petzer, Jacques P

2018-03-01

Monoamine oxidase (MAO) inhibitors, after the initial 'golden age', are currently used as third-line antidepressants (selective MAO-A inhibitors) or clinically enrolled as co-adjuvants for neurodegenerative diseases (selective MAO-B inhibitors). However, the research within this field is always increasing due to their pivotal role in modulating synaptic functions and monoamines metabolism. Areas covered: In this paper, MAO inhibitors (2015-2017) are disclosed ordering all the patents according to their chemical scaffold. Structure-activity relationships (SARs) are extrapolated for the most investigated chemotypes (coumarins, pyrazole/oxazepinones, (hetero)arylamides). 108 Compounds are divided into two main groups: newly synthesized molecules and naturally-occurring metabolites. Finally, new therapeutic options are outlined to ensure a more complete view on the potential of these inhibitors. Expert opinion: New proposed MAO inhibitors are endowed with a marked isoform selectivity, with innovative therapeutic potential toward other targets (gliomas, inflammation, muscle dystrophies, migraine, chronic pain, pseudobulbar affect), and with a promising ability to address multi-faceted pathologies such as Alzheimer's disease. The increasing number of patents is analyzed collecting data from 2002 to 2017.

Anti-angiogenic efficacy of 5′-triphosphate siRNA combining VEGF silencing and RIG-I activation in NSCLCs

PubMed Central

Meng, Gang; Xu, Chun; Song, Yong; Wei, Jiwu

2015-01-01

Short interfering RNA (siRNA) targeting angiogenic factors and further inhibiting tumor angiogenesis, is one of the potent antitumor candidates for lung cancer treatment. However, this strategy must be combined with other therapeutics like chemotherapy. In this study, we designed a 5′-triphosphate siRNA targeting VEGF (ppp-VEGF), and showed that ppp-VEGF exerted three distinct antitumor effects: i) inhibition of tumor angiogenesis by silencing VEGF, ii) induction of innate immune responses by activating RIG-I signaling pathway, and thus activate antitumor immunity, iii) induction of apoptosis. In a subcutaneous model of murine lung cancer, ppp-VEGF displayed a potent antitumor effect. Our results provide a multifunctional antitumor molecule that may overcome the shortages of traditional antiangiogenic agents. PMID:26336994

Design and Elaboration of a Tractable Tricyclic Scaffold To Synthesize Druglike Inhibitors of Dipeptidyl Peptidase-4 (DPP-4), Antagonists of the C-C Chemokine Receptor Type 5 (CCR5), and Highly Potent and Selective Phosphoinositol-3 Kinase δ (PI3Kδ) Inhibitors.

PubMed

Schwehm, Carolin; Kellam, Barrie; Garces, Aimie E; Hill, Stephen J; Kindon, Nicholas D; Bradshaw, Tracey D; Li, Jin; Macdonald, Simon J F; Rowedder, James E; Stoddart, Leigh A; Stocks, Michael J

2017-02-23

A novel molecular scaffold has been synthesized, and its incorporation into new analogues of biologically active molecules across multiple target classes will be discussed. In these studies, we have shown use of the tricyclic scaffold to synthesize potent inhibitors of the serine peptidase DPP-4, antagonists of the CCR5 receptor, and highly potent and selective PI3K δ isoform inhibitors. We also describe the predicted physicochemical properties of the resulting inhibitors and conclude that the tractable molecular scaffold could have potential application in future drug discovery programs.

Discovery and Characterization of CD12681, a Potent RORγ Inverse Agonist, Preclinical Candidate for the Topical Treatment of Psoriasis.

PubMed

Ouvry, Gilles; Atrux-Tallau, Nicolas; Bihl, Franck; Bondu, Aline; Bouix-Peter, Claire; Carlavan, Isabelle; Christin, Olivier; Cuadrado, Marie-Josée; Defoin-Platel, Claire; Deret, Sophie; Duvert, Denis; Feret, Christophe; Forissier, Mathieu; Fournier, Jean-François; Froude, David; Hacini-Rachinel, Fériel; Harris, Craig Steven; Hervouet, Catherine; Huguet, Hélène; Lafitte, Guillaume; Luzy, Anne-Pascale; Musicki, Branislav; Orfila, Danielle; Ozello, Benjamin; Pascau, Coralie; Pascau, Jonathan; Parnet, Véronique; Peluchon, Guillaume; Pierre, Romain; Piwnica, David; Raffin, Catherine; Rossio, Patricia; Spiesse, Delphine; Taquet, Nathalie; Thoreau, Etienne; Vatinel, Rodolphe; Vial, Emmanuel; Hennequin, Laurent François

2018-02-20

With possible implications in multiple autoimmune diseases, the retinoic acid receptor-related orphan receptor RORγ has become a sought-after target in the pharmaceutical industry. Herein are described the efforts to identify a potent RORγ inverse agonist compatible with topical application for the treatment of skin diseases. These efforts culminated in the discovery of N-(2,4-dimethylphenyl)-N-isobutyl-2-oxo-1-[(tetrahydro-2H-pyran-4-yl)methyl]-2,3-dihydro-1H-benzo[d]imidazole-5-sulfonamide (CD12681), a potent inverse agonist with in vivo activity in an IL-23-induced mouse skin inflammation model. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polyvalent Recognition of Biopolymers:The Design of Potent Inhibitors of Anthrax Toxin

NASA Astrophysics Data System (ADS)

Kane, Ravi

2007-03-01

Polyvalency -- the simultaneous binding of multiple ligands on one entity to multiple receptors on another -- is a phenomenon that is ubiquitous in nature. We are using a biomimetic approach, inspired by polyvalency, to design potent inhibitors of anthrax toxin. Since the major symptoms and death from anthrax are due primarily to the action of anthrax toxin, the toxin is a prime target for therapeutic intervention. We describe the design of potent polyvalent anthrax toxin inhibitors, and will discuss the role of pattern matching in polyvalent recognition. Pattern-matched polyvalent inhibitors can neutralize anthrax toxin in vivo, and may enable the successful treatment of anthrax during the later stages of the disease, when antibiotic treatment is ineffective.

Pros and Cons of Antigen-Presenting Cell Targeted Tumor Vaccines.

PubMed

Goyvaerts, Cleo; Breckpot, Karine

2015-01-01

In therapeutic antitumor vaccination, dendritic cells play the leading role since they decide if, how, when, and where a potent antitumor immune response will take place. Since the disentanglement of the complexity and merit of different antigen-presenting cell subtypes, antitumor immunotherapeutic research started to investigate the potential benefit of targeting these subtypes in situ. This review will discuss which antigen-presenting cell subtypes are at play and how they have been targeted and finally question the true meaning of targeting antitumor-based vaccines.

Fragment Linking and Optimization of Inhibitors of the Aspartic Protease Endothiapepsin: Fragment‐Based Drug Design Facilitated by Dynamic Combinatorial Chemistry

PubMed Central

Mondal, Milon; Radeva, Nedyalka; Fanlo‐Virgós, Hugo; Otto, Sijbren; Klebe, Gerhard

2016-01-01

Abstract Fragment‐based drug design (FBDD) affords active compounds for biological targets. While there are numerous reports on FBDD by fragment growing/optimization, fragment linking has rarely been reported. Dynamic combinatorial chemistry (DCC) has become a powerful hit‐identification strategy for biological targets. We report the synergistic combination of fragment linking and DCC to identify inhibitors of the aspartic protease endothiapepsin. Based on X‐ray crystal structures of endothiapepsin in complex with fragments, we designed a library of bis‐acylhydrazones and used DCC to identify potent inhibitors. The most potent inhibitor exhibits an IC50 value of 54 nm, which represents a 240‐fold improvement in potency compared to the parent hits. Subsequent X‐ray crystallography validated the predicted binding mode, thus demonstrating the efficiency of the combination of fragment linking and DCC as a hit‐identification strategy. This approach could be applied to a range of biological targets, and holds the potential to facilitate hit‐to‐lead optimization. PMID:27400756

Putative kappa opioid heteromers as targets for developing analgesics free of adverse effects.

PubMed

Le Naour, Morgan; Lunzer, Mary M; Powers, Michael D; Kalyuzhny, Alexander E; Benneyworth, Michael A; Thomas, Mark J; Portoghese, Philip S

2014-08-14

It is now generally recognized that upon activation by an agonist, β-arrestin associates with G protein-coupled receptors and acts as a scaffold in creating a diverse signaling network that could lead to adverse effects. As an approach to reducing side effects associated with κ opioid agonists, a series of β-naltrexamides 3-10 was synthesized in an effort to selectively target putative κ opioid heteromers without recruiting β-arrestin upon activation. The most potent derivative 3 (INTA) strongly activated KOR-DOR and KOR-MOR heteromers in HEK293 cells. In vivo studies revealed 3 to produce potent antinociception, which, when taken together with antagonism data, was consistent with the activation of both heteromers. 3 was devoid of tolerance, dependence, and showed no aversive effect in the conditioned place preference assay. As immunofluorescence studies indicated no recruitment of β-arrestin2 to membranes in coexpressed KOR-DOR cells, this study suggests that targeting of specific putative heteromers has the potential to identify leads for analgesics devoid of adverse effects.

Selective and Specific Inhibition of the Plasmodium falciparum Lysyl-tRNA Synthetase by the Fungal Secondary Metabolite Cladosporin

PubMed Central

Hoepfner, Dominic; McNamara, Case W.; Lim, Chek Shik; Studer, Christian; Riedl, Ralph; Aust, Thomas; McCormack, Susan L.; Plouffe, David M.; Meister, Stephan; Schuierer, Sven; Plikat, Uwe; Hartmann, Nicole; Staedtler, Frank; Cotesta, Simona; Schmitt, Esther K.; Petersen, Frank; Supek, Frantisek; Glynne, Richard J.; Tallarico, John A.; Porter, Jeffrey A.; Fishman, Mark C.; Bodenreider, Christophe; Diagana, Thierry T.; Movva, N. Rao; Winzeler, Elizabeth A.

2012-01-01

Summary With renewed calls for malaria eradication, next-generation antimalarials need be active against drug-resistant parasites and efficacious against both liver- and blood-stage infections. We screened a natural product library to identify inhibitors of Plasmodium falciparum blood- and liver-stage proliferation. Cladosporin, a fungal secondary metabolite whose target and mechanism of action are not known for any species, was identified as having potent, nanomolar, antiparasitic activity against both blood and liver stages. Using postgenomic methods, including a yeast deletion strains collection, we show that cladosporin specifically inhibits protein synthesis by directly targeting P. falciparum cytosolic lysyl-tRNA synthetase. Further, cladosporin is >100-fold more potent against parasite lysyl-tRNA synthetase relative to the human enzyme, which is conferred by the identity of two amino acids within the enzyme active site. Our data indicate that lysyl-tRNA synthetase is an attractive, druggable, antimalarial target that can be selectively inhibited. PMID:22704625

Selective and specific inhibition of the plasmodium falciparum lysyl-tRNA synthetase by the fungal secondary metabolite cladosporin.

PubMed

Hoepfner, Dominic; McNamara, Case W; Lim, Chek Shik; Studer, Christian; Riedl, Ralph; Aust, Thomas; McCormack, Susan L; Plouffe, David M; Meister, Stephan; Schuierer, Sven; Plikat, Uwe; Hartmann, Nicole; Staedtler, Frank; Cotesta, Simona; Schmitt, Esther K; Petersen, Frank; Supek, Frantisek; Glynne, Richard J; Tallarico, John A; Porter, Jeffrey A; Fishman, Mark C; Bodenreider, Christophe; Diagana, Thierry T; Movva, N Rao; Winzeler, Elizabeth A

2012-06-14

With renewed calls for malaria eradication, next-generation antimalarials need be active against drug-resistant parasites and efficacious against both liver- and blood-stage infections. We screened a natural product library to identify inhibitors of Plasmodium falciparum blood- and liver-stage proliferation. Cladosporin, a fungal secondary metabolite whose target and mechanism of action are not known for any species, was identified as having potent, nanomolar, antiparasitic activity against both blood and liver stages. Using postgenomic methods, including a yeast deletion strains collection, we show that cladosporin specifically inhibits protein synthesis by directly targeting P. falciparum cytosolic lysyl-tRNA synthetase. Further, cladosporin is >100-fold more potent against parasite lysyl-tRNA synthetase relative to the human enzyme, which is conferred by the identity of two amino acids within the enzyme active site. Our data indicate that lysyl-tRNA synthetase is an attractive, druggable, antimalarial target that can be selectively inhibited. Copyright © 2012 Elsevier Inc. All rights reserved.

The insecticide target in the PSST subunit of complex I.

PubMed

Schuler, F; Casida, J E

2001-10-01

Current insecticides have been selected by sifting and winnowing hundreds of thousands of synthetic chemicals and natural products to obtain commercial preparations of optimal effectiveness and safety. This process has often ended up with compounds of high potency as inhibitors of the electron transport chain and more specifically of complex I (NADH:ubiquinone oxidoreductase). Many classes of chemicals are involved and the enzyme is one of the most complicated known, with 43 subunits catalyzing electron transfer from NADH to ubiquinone through flavin mononucleotide and up to eight iron-sulfur clusters. We used a potent photoaffinity ligand, (trifluoromethyl)diazirinyl[3H]pyridaben, to localize the insecticide target to a single high-affinity site in the PSST subunit that couples electron transfer from iron-sulfur cluster N2 to ubiquinone. Most importantly, all of the potent complex I-inhibiting pesticides, despite their great structural diversity, compete for this same specific binding domain in PSST. Finding their common mode of action and target provides insight into shared toxicological features and potential selection for resistant pests.

Application of encoded library technology (ELT) to a protein-protein interaction target: discovery of a potent class of integrin lymphocyte function-associated antigen 1 (LFA-1) antagonists.

PubMed

Kollmann, Christopher S; Bai, Xiaopeng; Tsai, Ching-Hsuan; Yang, Hongfang; Lind, Kenneth E; Skinner, Steven R; Zhu, Zhengrong; Israel, David I; Cuozzo, John W; Morgan, Barry A; Yuki, Koichi; Xie, Can; Springer, Timothy A; Shimaoka, Motomu; Evindar, Ghotas

2014-04-01

The inhibition of protein-protein interactions remains a challenge for traditional small molecule drug discovery. Here we describe the use of DNA-encoded library technology for the discovery of small molecules that are potent inhibitors of the interaction between lymphocyte function-associated antigen 1 and its ligand intercellular adhesion molecule 1. A DNA-encoded library with a potential complexity of 4.1 billion compounds was exposed to the I-domain of the target protein and the bound ligands were affinity selected, yielding an enriched small-molecule hit family. Compounds representing this family were synthesized without their DNA encoding moiety and found to inhibit the lymphocyte function-associated antigen 1/intercellular adhesion molecule-1 interaction with submicromolar potency in both ELISA and cell adhesion assays. Re-synthesized compounds conjugated to DNA or a fluorophore were demonstrated to bind to cells expressing the target protein. Copyright © 2014 Elsevier Ltd. All rights reserved.

High-throughput spectral and lifetime-based FRET screening in living cells to identify small-molecule effectors of SERCA

PubMed Central

Schaaf, Tory M.; Peterson, Kurt C.; Grant, Benjamin D.; Bawaskar, Prachi; Yuen, Samantha; Li, Ji; Muretta, Joseph M.; Gillispie, Gregory D.; Thomas, David D.

2017-01-01

A robust high-throughput screening (HTS) strategy has been developed to discover small-molecule effectors targeting the sarco/endoplasmic reticulum calcium ATPase (SERCA), based on a fluorescence microplate reader that records both the nanosecond decay waveform (lifetime mode) and the complete emission spectrum (spectral mode), with high precision and speed. This spectral unmixing plate reader (SUPR) was used to screen libraries of small molecules with a fluorescence resonance energy transfer (FRET) biosensor expressed in living cells. Ligand binding was detected by FRET associated with structural rearrangements of green (GFP, donor) and red (RFP, acceptor) fluorescent proteins fused to the cardiac-specific SERCA2a isoform. The results demonstrate accurate quantitation of FRET along with high precision of hit identification. Fluorescence lifetime analysis resolved SERCA’s distinct structural states, providing a method to classify small-molecule chemotypes on the basis of their structural effect on the target. The spectral analysis was also applied to flag interference by fluorescent compounds. FRET hits were further evaluated for functional effects on SERCA’s ATPase activity via both a coupled-enzyme assay and a FRET-based calcium sensor. Concentration-response curves indicated excellent correlation between FRET and function. These complementary spectral and lifetime FRET detection methods offer an attractive combination of precision, speed, and resolution for HTS. PMID:27899691

When No Response Is a Good Thing | Center for Cancer Research

Cancer.gov

Custom-designed therapies that target cell-surface antigens or receptors represent a promising immunological approach in cancer therapy. Antibodies that bind these targets are the starting point.  Potent toxins can then be added to them by fusing antibody fragments to powerful bacterial toxins such as Pseudomonas exotoxin (PE). This recombinant immunotoxin combines antibody

Targeting Alpha5 Beta1 Integrin to Prevent Metastatic Breast Cancer Cell Invasion: PhScN Target Site Definition and Plasma Stability

DTIC Science & Technology

2014-09-01

Staszewski, et al., The PHSCN dendrimer as a more potent inhibitor of human breast cancer cell invasion, extravasation, and lung colony formation...the PHSCN dendrimer as an inhibitor of human prostate cancer cell invasion, extravasation, and lung colony formation. Clin Exp Metastasis, 2010. 27(3

Quantitative determination of phenolic compounds by UHPLC-UV-MS and use of principal component analysis to differentiate chemo-types of chamomile/chrysanthemum flowerheads

USDA-ARS?s Scientific Manuscript database

A new rapid UHPLC-UV-QTOF/MS method has been developed for the simultaneous analysis of nine phenolic compounds [cis-GMCA, chlorogenic acid, trans-GMCA, quercetagetin-7-O-ß-D-glucopyranoside, luteolin-7-O-ß-D-glucoside, apigenin-7-O- ß-Dglucoside, chamaemeloside, apigenin 7-O-(6"-O-acetyl-ß-D-glucop...

Discovery of LY2457546: a multi-targeted anti-angiogenic kinase inhibitor with a novel spectrum of activity and exquisite potency in the acute myelogenous leukemia-Flt-3-internal tandem duplication mutant human tumor xenograft model.

PubMed

Burkholder, Timothy P; Clayton, Joshua R; Rempala, Mark E; Henry, James R; Knobeloch, John M; Mendel, David; McLean, Johnathan A; Hao, Yan; Barda, David A; Considine, Eileen L; Uhlik, Mark T; Chen, Yuefeng; Ma, Liandong; Bloem, Laura J; Akunda, Jacqueline K; McCann, Denis J; Sanchez-Felix, Manuel; Clawson, David K; Lahn, Michael M; Starling, James J

2012-06-01

LY2457546 is a potent and orally bioavailable inhibitor of multiple receptor tyrosine kinases involved in angiogenic and tumorigenic signalling. In biochemical and cellular assays, LY2457546 demonstrates potent activity against targets that include VEGFR2 (KDR), PDGFRβ, FLT-3, Tie-2 and members of the Eph family of receptors. With activities against both Tie2 and Eph receptors, LY2457546 possesses an activity profile that distinguishes it from multikinase inhibitors. When compared head to head with sunitinib, LY2457546 was more potent for inhibition of endothelial tube formation in an in vitro angiogenesis co-culture model with an intermittent treatment design. In vivo, LY2457546 inhibited VEGF-driven autophosphorylation of lung KDR in the mouse and rat in a dose and concentration dependent manner. LY2457546 was well tolerated and exhibited efficacy in a 13762 syngeneic rat mammary tumor model in both once and twice daily continuous dosing schedules and in mouse human tumor xenograft models of lung, colon, and prostate origin. Additionally, LY2457546 caused complete regression of well-established tumors in an acute myelogenous leukemia (AML) FLT3-ITD mutant xenograft tumor model. The observed efficacy that was displayed by LY2457546 in the AML FLT3-ITD mutant tumor model was superior to sunitinib when both were evaluated using equivalent doses normalized to in vivo inhibition of pKDR in mouse lung. LY2457546 was well tolerated in non-clinical toxicology studies conducted in rats and dogs. The majority of the toxicities observed were similar to those observed with other multi-targeted anti-angiogenic kinase inhibitors (MAKs) and included bone marrow hypocellularity, hair and skin depigmentation, cartilage dysplasia and lymphoid organ degeneration and necrosis. Thus, the unique spectrum of target activity, potent in vivo anti-tumor efficacy in a variety of rodent and human solid tumor models, exquisite potency against a clinically relevant model of AML, and non-clinical safety profile justify the advancement of LY2457546 into clinical testing.

Activated matriptase as a target to treat breast cancer with a drug conjugate

PubMed Central

Lin, Hongxia; Banach-Petrosky, Whitney; Hirshfield, Kim M.; Lin, Chen-Yong; Johnson, Michael D.; Szekely, Zoltan; Bertino, Joseph R.

2018-01-01

The antitumor effects of a novel antibody drug conjugate (ADC) was tested against human solid tumor cell lines and against human triple negative breast cancer (TNBC) xenografts in immunosuppressed mice. The ADC targeting activated matriptase of tumor cells was synthesized by using the potent anti-tubulin toxin, monomethyl auristatin-E linked to the activated matriptase-specific monoclonal antibody (M69) via a lysosomal protease-cleavable dipeptide linker. This ADC was found to be cytotoxic against multiple activated matriptase-positive epithelial carcinoma cell lines in vitro and markedly inhibited growth of triple negative breast cancer xenografts and a primary human TNBC (PDX) in vivo. Overexpression of activated matriptase may be a biomarker for response to this ADC. The ADC had potent anti-tumor activity, while the unconjugated M69 antibody was ineffective in a mouse model study using MDA-MB-231 xenografts in mice. Treatment of a human TNBC (MDA-MB-231) showed potent anti-tumor effects in combination with cisplatin in mice. This ADC alone or in combination with cisplatin has the potential to improve the treatment outcomes of patients with TNBC as well as other tumors overexpressing activated matriptase. PMID:29899836

Discovery of a Potent BTK Inhibitor with a Novel Binding Mode by Using Parallel Selections with a DNA-Encoded Chemical Library.

PubMed

Cuozzo, John W; Centrella, Paolo A; Gikunju, Diana; Habeshian, Sevan; Hupp, Christopher D; Keefe, Anthony D; Sigel, Eric A; Soutter, Holly H; Thomson, Heather A; Zhang, Ying; Clark, Matthew A

2017-05-04

We have identified and characterized novel potent inhibitors of Bruton's tyrosine kinase (BTK) from a single DNA-encoded library of over 110 million compounds by using multiple parallel selection conditions, including variation in target concentration and addition of known binders to provide competition information. Distinct binding profiles were observed by comparing enrichments of library building block combinations under these conditions; one enriched only at high concentrations of BTK and was competitive with ATP, and another enriched at both high and low concentrations of BTK and was not competitive with ATP. A compound representing the latter profile showed low nanomolar potency in biochemical and cellular BTK assays. Results from kinetic mechanism of action studies were consistent with the selection profiles. Analysis of the co-crystal structure of the most potent compound demonstrated a novel binding mode that revealed a new pocket in BTK. Our results demonstrate that profile-based selection strategies using DNA-encoded libraries form the basis of a new methodology to rapidly identify small molecule inhibitors with novel binding modes to clinically relevant targets. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Withaferin A, a natural compound with anti-tumor activity, is a potent inhibitor of transcription factor C/EBPβ.

PubMed

Falkenberg, Kim D; Jakobs, Anke; Matern, Julian C; Dörner, Wolfgang; Uttarkar, Sagar; Trentmann, Amke; Steinmann, Simone; Coulibaly, Anna; Schomburg, Caroline; Mootz, Henning D; Schmidt, Thomas J; Klempnauer, Karl-Heinz

2017-07-01

Recent work has shown that deregulation of the transcription factor Myb contributes to the development of leukemia and several other human cancers, making Myb and its cooperation partners attractive targets for drug development. By employing a myeloid Myb-reporter cell line we have identified Withaferin A (WFA), a natural compound that exhibits anti-tumor activities, as an inhibitor of Myb-dependent transcription. Analysis of the inhibitory mechanism of WFA showed that WFA is a significantly more potent inhibitor of C/EBPβ, a transcription factor cooperating with Myb in myeloid cells, than of Myb itself. We show that WFA covalently modifies specific cysteine residues of C/EBPβ, resulting in the disruption of the interaction of C/EBPβ with the co-activator p300. Our work identifies C/EBPβ as a novel direct target of WFA and highlights the role of p300 as a crucial co-activator of C/EBPβ. The finding that WFA is a potent inhibitor of C/EBPβ suggests that inhibition of C/EBPβ might contribute to the biological activities of WFA. Copyright © 2017 Elsevier B.V. All rights reserved.

A screen of chemical modifications identifies position-specific modification by UNA to most potently reduce siRNA off-target effects

PubMed Central

Bramsen, Jesper B.; Pakula, Malgorzata M.; Hansen, Thomas B.; Bus, Claus; Langkjær, Niels; Odadzic, Dalibor; Smicius, Romualdas; Wengel, Suzy L.; Chattopadhyaya, Jyoti; Engels, Joachim W.; Herdewijn, Piet; Wengel, Jesper; Kjems, Jørgen

2010-01-01

Small interfering RNAs (siRNAs) are now established as the preferred tool to inhibit gene function in mammalian cells yet trigger unintended gene silencing due to their inherent miRNA-like behavior. Such off-target effects are primarily mediated by the sequence-specific interaction between the siRNA seed regions (position 2–8 of either siRNA strand counting from the 5′-end) and complementary sequences in the 3′UTR of (off-) targets. It was previously shown that chemical modification of siRNAs can reduce off-targeting but only very few modifications have been tested leaving more to be identified. Here we developed a luciferase reporter-based assay suitable to monitor siRNA off-targeting in a high throughput manner using stable cell lines. We investigated the impact of chemically modifying single nucleotide positions within the siRNA seed on siRNA function and off-targeting using 10 different types of chemical modifications, three different target sequences and three siRNA concentrations. We found several differently modified siRNAs to exercise reduced off-targeting yet incorporation of the strongly destabilizing unlocked nucleic acid (UNA) modification into position 7 of the siRNA most potently reduced off-targeting for all tested sequences. Notably, such position-specific destabilization of siRNA–target interactions did not significantly reduce siRNA potency and is therefore well suited for future siRNA designs especially for applications in vivo where siRNA concentrations, expectedly, will be low. PMID:20453030

A toxic RNA catalyzes the in cellulo synthesis of its own inhibitor.

PubMed

Rzuczek, Suzanne G; Park, HaJeung; Disney, Matthew D

2014-10-06

Potent modulators of RNA function can be assembled in cellulo by using the cell as a reaction vessel and a disease-causing RNA as a catalyst. When designing small molecule effectors of function, a balance between permeability and potency must be struck. Low molecular weight compounds are more permeable whereas higher molecular weight compounds are more potent. The advantages of both types of compounds could be synergized if low molecular weight molecules could be transformed into potent, multivalent ligands by a reaction that is catalyzed by binding to a target in cells expressing a genetic defect. It was shown that this approach is indeed viable in cellulo. Small molecule modules with precisely positioned alkyne and azide moieties bind adjacent internal loops in r(CCUG)(exp), the causative agent of myotonic dystrophy type 2 (DM2), and are transformed into oligomeric, potent inhibitors of DM2 RNA dysfunction by a Huisgen 1,3-dipolar cycloaddition reaction, a variant of click chemistry. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Discovery of 3-(3-(4-(1-Aminocyclobutyl)phenyl)-5-phenyl-3 H -imidazo[4,5- b ]pyridin-2-yl)pyridin-2-amine (ARQ 092): An Orally Bioavailable, Selective, and Potent Allosteric AKT Inhibitor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lapierre, Jean-Marc; Eathiraj, Sudharshan; Vensel, David

The work in this paper describes the optimization of the 3-(3-phenyl-3H-imidazo[4,5-b]pyridin-2-yl)pyridin-2-amine chemical series as potent, selective allosteric inhibitors of AKT kinases, leading to the discovery of ARQ 092 (21a). The cocrystal structure of compound 21a bound to full-length AKT1 confirmed the allosteric mode of inhibition of this chemical class and the role of the cyclobutylamine moiety. Compound 21a demonstrated high enzymatic potency against AKT1, AKT2, and AKT3, as well as potent cellular inhibition of AKT activation and the phosphorylation of the downstream target PRAS40. Compound 21a also served as a potent inhibitor of the AKT1-E17K mutant protein and inhibited tumormore » growth in a human xenograft mouse model of endometrial adenocarcinoma.« less

4-aminoquinolone piperidine amides: noncovalent inhibitors of DprE1 with long residence time and potent antimycobacterial activity.

PubMed

Naik, Maruti; Humnabadkar, Vaishali; Tantry, Subramanyam J; Panda, Manoranjan; Narayan, Ashwini; Guptha, Supreeth; Panduga, Vijender; Manjrekar, Praveena; Jena, Lalit Kumar; Koushik, Krishna; Shanbhag, Gajanan; Jatheendranath, Sandesh; Manjunatha, M R; Gorai, Gopinath; Bathula, Chandramohan; Rudrapatna, Suresh; Achar, Vijayashree; Sharma, Sreevalli; Ambady, Anisha; Hegde, Naina; Mahadevaswamy, Jyothi; Kaur, Parvinder; Sambandamurthy, Vasan K; Awasthy, Disha; Narayan, Chandan; Ravishankar, Sudha; Madhavapeddi, Prashanti; Reddy, Jitendar; Prabhakar, Kr; Saralaya, Ramanatha; Chatterji, Monalisa; Whiteaker, James; McLaughlin, Bob; Chiarelli, Laurent R; Riccardi, Giovanna; Pasca, Maria Rosalia; Binda, Claudia; Neres, João; Dhar, Neeraj; Signorino-Gelo, François; McKinney, John D; Ramachandran, Vasanthi; Shandil, Radha; Tommasi, Ruben; Iyer, Pravin S; Narayanan, Shridhar; Hosagrahara, Vinayak; Kavanagh, Stefan; Dinesh, Neela; Ghorpade, Sandeep R

2014-06-26

4-Aminoquinolone piperidine amides (AQs) were identified as a novel scaffold starting from a whole cell screen, with potent cidality on Mycobacterium tuberculosis (Mtb). Evaluation of the minimum inhibitory concentrations, followed by whole genome sequencing of mutants raised against AQs, identified decaprenylphosphoryl-β-d-ribose 2'-epimerase (DprE1) as the primary target responsible for the antitubercular activity. Mass spectrometry and enzyme kinetic studies indicated that AQs are noncovalent, reversible inhibitors of DprE1 with slow on rates and long residence times of ∼100 min on the enzyme. In general, AQs have excellent leadlike properties and good in vitro secondary pharmacology profile. Although the scaffold started off as a single active compound with moderate potency from the whole cell screen, structure-activity relationship optimization of the scaffold led to compounds with potent DprE1 inhibition (IC50 < 10 nM) along with potent cellular activity (MIC = 60 nM) against Mtb.

Novel GABA receptor pesticide targets.

PubMed

Casida, John E; Durkin, Kathleen A

2015-06-01

The γ-aminobutyric acid (GABA) receptor has four distinct but overlapping and coupled targets of pesticide action importantly associated with little or no cross-resistance. The target sites are differentiated by binding assays with specific radioligands, resistant strains, site-directed mutagenesis and molecular modeling. Three of the targets are for non-competitive antagonists (NCAs) or channel blockers of widely varied chemotypes. The target of the first generation (20th century) NCAs differs between the larger or elongated compounds (NCA-IA) including many important insecticides of the past (cyclodienes and polychlorocycloalkanes) or present (fiproles) and the smaller or compact compounds (NCA-IB) highly toxic to mammals and known as cage convulsants, rodenticides or chemical threat agents. The target of greatest current interest is designated NCA-II for the second generation (21st century) of NCAs consisting for now of isoxazolines and meta-diamides. This new and uniquely different NCA-II site apparently differs enough between insects and mammals to confer selective toxicity. The fourth target is the avermectin site (AVE) for allosteric modulators of the chloride channel. NCA pesticides vary in molecular surface area and solvent accessible volume relative to avermectin with NCA-IBs at 20-22%, NCA-IAs at 40-45% and NCA-IIs at 57-60%. The same type of relationship relative to ligand-docked length is 27-43% for NCA-IBs, 63-71% for NCA-IAs and 85-105% for NCA-IIs. The four targets are compared by molecular modeling for the Drosophila melanogaster GABA-R. The principal sites of interaction are proposed to be: pore V1' and A2' for NCA-IB compounds; pore A2', L6' and T9' for NCA-IA compounds; pore T9' to S15' in proximity to M1/M3 subunit interface (or alternatively an interstitial site) for NCA-II compounds; and M1/M3, M2 interfaces for AVE. Understanding the relationships of these four binding sites is important in resistance management and in the discovery and use of safe and effective pest control agents. Copyright © 2014 Elsevier Inc. All rights reserved.

Exploring the utility of organo-polyoxometalate hybrids to inhibit SOX transcription factors

PubMed Central

2014-01-01

Background SOX transcription factors constitute an attractive target class for intervention with small molecules as they play a prominent role in the field of regenerative biomedicine and cancer biology. However, rationally engineering specific inhibitors that interfere with transcription factor DNA interfaces continues to be a monumental challenge in the field of transcription factor chemical biology. Polyoxometalates (POMs) are inorganic compounds that were previously shown to target the high-mobility group (HMG) of SOX proteins at nanomolar concentrations. In continuation of this work, we carried out an assessment of the selectivity of a panel of newly synthesized organo-polyoxometalate hybrids in targeting different transcription factor families to enable the usage of polyoxometalates as specific SOX transcription factor drugs. Results The residual DNA-binding activities of 15 different transcription factors were measured after treatment with a panel of diverse polyoxometalates. Polyoxometalates belonging to the Dawson structural class were found to be more potent inhibitors than the Keggin class. Further, organically modified Dawson polyoxometalates were found to be the most potent in inhibiting transcription factor DNA binding activity. The size of the polyoxometalates and its derivitization were found to be the key determinants of their potency. Conclusion Polyoxometalates are highly potent, nanomolar range inhibitors of the DNA binding activity of the Sox-HMG family. However, binding assays involving a limited subset of structurally diverse polyoxometalates revealed a low selectivity profile against different transcription factor families. Further progress in achieving selectivity and deciphering structure-activity relationship of POMs require the identification of POM binding sites on transcription factors using elaborate approaches like X-ray crystallography and multidimensional NMR. In summary, our report reaffirms that transcription factors are challenging molecular architectures and that future polyoxometalate chemistry must consider further modification strategies, to address the substantial challenges involved in achieving target selectivity. PMID:25678957

Design, synthesis and biological evaluation of pyrazolylaminoquinazoline derivatives as highly potent pan-fibroblast growth factor receptor inhibitors.

PubMed

Fan, Jun; Dai, Yang; Shao, Jingwei; Peng, Xia; Wang, Chen; Cao, Sufen; Zhao, Bin; Ai, Jing; Geng, Meiyu; Duan, Wenhu

2016-06-01

Fibroblast growth factor receptors (FGFRs) are important oncology targets due to the dysregulation of this signaling pathway in a wide variety of human cancers. We identified a series of pyrazolylaminoquinazoline derivatives as potent FGFR inhibitors with low nanomolar potency. The representative compound 29 strongly inhibited FGFR1-3 kinase activity and suppressed FGFR signaling transduction in FGFR-addicted cancer cells; FGFRs-driven cell proliferation was also strongly inhibited regardless of mechanistic complexity implicated in FGFR activation, which further confirmed that 29 was a potent pan-FGFR inhibitor. The flexibility of our structure offered the potential to preserve good affinity for mutant FGFR, which is important for developing TKIs with long-term efficacy. Copyright © 2016 Elsevier Ltd. All rights reserved.

Antagonizing STAT3 dimerization with a rhodium(III) complex.

PubMed

Ma, Dik-Lung; Liu, Li-Juan; Leung, Ka-Ho; Chen, Yen-Ting; Zhong, Hai-Jing; Chan, Daniel Shiu-Hin; Wang, Hui-Min David; Leung, Chung-Hang

2014-08-25

Kinetically inert metal complexes have arisen as promising alternatives to existing platinum and ruthenium chemotherapeutics. Reported herein, to our knowledge, is the first example of a substitutionally inert, Group 9 organometallic compound as a direct inhibitor of signal transducer and activator of transcription 3 (STAT3) dimerization. From a series of cyclometalated rhodium(III) and iridium(III) complexes, a rhodium(III) complex emerged as a potent inhibitor of STAT3 that targeted the SH2 domain and inhibited STAT3 phosphorylation and dimerization. Significantly, the complex exhibited potent anti-tumor activities in an in vivo mouse xenograft model of melanoma. This study demonstrates that rhodium complexes may be developed as effective STAT3 inhibitors with potent anti-tumor activity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A potent series targeting the malarial cGMP-dependent protein kinase clears infection and blocks transmission.

PubMed

Baker, David A; Stewart, Lindsay B; Large, Jonathan M; Bowyer, Paul W; Ansell, Keith H; Jiménez-Díaz, María B; El Bakkouri, Majida; Birchall, Kristian; Dechering, Koen J; Bouloc, Nathalie S; Coombs, Peter J; Whalley, David; Harding, Denise J; Smiljanic-Hurley, Ela; Wheldon, Mary C; Walker, Eloise M; Dessens, Johannes T; Lafuente, María José; Sanz, Laura M; Gamo, Francisco-Javier; Ferrer, Santiago B; Hui, Raymond; Bousema, Teun; Angulo-Barturén, Iñigo; Merritt, Andy T; Croft, Simon L; Gutteridge, Winston E; Kettleborough, Catherine A; Osborne, Simon A

2017-09-05

To combat drug resistance, new chemical entities are urgently required for use in next generation anti-malarial combinations. We report here the results of a medicinal chemistry programme focused on an imidazopyridine series targeting the Plasmodium falciparum cyclic GMP-dependent protein kinase (PfPKG). The most potent compound (ML10) has an IC 50 of 160 pM in a PfPKG kinase assay and inhibits P. falciparum blood stage proliferation in vitro with an EC 50 of 2.1 nM. Oral dosing renders blood stage parasitaemia undetectable in vivo using a P. falciparum SCID mouse model. The series targets both merozoite egress and erythrocyte invasion, but crucially, also blocks transmission of mature P. falciparum gametocytes to Anopheles stephensi mosquitoes. A co-crystal structure of PvPKG bound to ML10, reveals intimate molecular contacts that explain the high levels of potency and selectivity we have measured. The properties of this series warrant consideration for further development to produce an antimalarial drug.Protein kinases are promising drug targets for treatment of malaria. Here, starting with a medicinal chemistry approach, Baker et al. generate an imidazopyridine that selectively targets Plasmodium falciparum PKG, inhibits blood stage parasite growth in vitro and in mice and blocks transmission to mosquitoes.

Discovery of host-targeted covalent inhibitors of dengue virus

PubMed Central

de Wispelaere, Mélissanne; Carocci, Margot; Liang, Yanke; Liu, Qingsong; Sun, Eileen; Vetter, Michael L.; Wang, Jinhua; Gray, Nathanael S.; Yang, Priscilla L.

2017-01-01

We report here on an approach targeting the host reactive cysteinome to identify inhibitors of host factors required for the infectious cycle of Flaviviruses and other viruses. We used two parallel cellular phenotypic screens to identify a series of covalent inhibitors, exemplified by QL-XII-47, that are active against dengue virus. We show that the compounds effectively block viral protein expression and that this inhibition is associated with repression of downstream processes of the infectious cycle, and thus significantly contributes to the potent antiviral activity of these compounds. We demonstrate that QL-XII-47’s antiviral activity requires selective, covalent modification of a host target by showing that the compound's antiviral activity is recapitulated when cells are preincubated with QL-XII-47 and then washed prior to viral infection and by showing that QL-XII-47R, a non-reactive analog, lacks antiviral activity at concentrations more than 20-fold higher than QL-XII-47's IC90. QL-XII-47’s inhibition of Zika virus, West Nile virus, hepatitis C virus, and poliovirus further suggests that it acts via a target mediating inhibition of these other medically relevant viruses. These results demonstrate the utility of screens targeting the host reactive cysteinome for rapid identification of compounds with potent antiviral activity. PMID:28034743

Stapled α−helical peptide drug development: A potent dual inhibitor of MDM2 and MDMX for p53-dependent cancer therapy

PubMed Central

Chang, Yong S.; Graves, Bradford; Guerlavais, Vincent; Tovar, Christian; Packman, Kathryn; To, Kwong-Him; Olson, Karen A.; Kesavan, Kamala; Gangurde, Pranoti; Mukherjee, Aditi; Baker, Theresa; Darlak, Krzysztof; Elkin, Carl; Filipovic, Zoran; Qureshi, Farooq Z.; Cai, Hongliang; Berry, Pamela; Feyfant, Eric; Shi, Xiangguo E.; Horstick, James; Annis, D. Allen; Manning, Anthony M.; Fotouhi, Nader; Nash, Huw; Vassilev, Lyubomir T.; Sawyer, Tomi K.

2013-01-01

Stapled α−helical peptides have emerged as a promising new modality for a wide range of therapeutic targets. Here, we report a potent and selective dual inhibitor of MDM2 and MDMX, ATSP-7041, which effectively activates the p53 pathway in tumors in vitro and in vivo. Specifically, ATSP-7041 binds both MDM2 and MDMX with nanomolar affinities, shows submicromolar cellular activities in cancer cell lines in the presence of serum, and demonstrates highly specific, on-target mechanism of action. A high resolution (1.7-Å) X-ray crystal structure reveals its molecular interactions with the target protein MDMX, including multiple contacts with key amino acids as well as a role for the hydrocarbon staple itself in target engagement. Most importantly, ATSP-7041 demonstrates robust p53-dependent tumor growth suppression in MDM2/MDMX-overexpressing xenograft cancer models, with a high correlation to on-target pharmacodynamic activity, and possesses favorable pharmacokinetic and tissue distribution properties. Overall, ATSP-7041 demonstrates in vitro and in vivo proof-of-concept that stapled peptides can be developed as therapeutically relevant inhibitors of protein–protein interaction and may offer a viable modality for cancer therapy. PMID:23946421

Tofacitinib and analogs as inhibitors of the histone kinase PRK1 (PKN1).

PubMed

Ostrovskyi, Dmytro; Rumpf, Tobias; Eib, Julia; Lumbroso, Alexandre; Slynko, Inna; Klaeger, Susan; Heinzlmeir, Stephanie; Forster, Michael; Gehringer, Matthias; Pfaffenrot, Ellen; Bauer, Silke Mona; Schmidtkunz, Karin; Wenzler, Sandra; Metzger, Eric; Kuster, Bernhard; Laufer, Stefan; Schüle, Roland; Sippl, Wolfgang; Breit, Bernhard; Jung, Manfred

2016-09-01

The histone kinase PRK1 has been identified as a potential target to combat prostate cancer but selective PRK1 inhibitors are lacking. The US FDA -approved JAK1-3 inhibitor tofacitinib also potently inhibits PRK1 in vitro. We show that tofacitinib also inhibits PRK1 in a cellular setting. Using tofacitinib as a starting point for structure-activity relationship studies, we identified a more potent and another more selective PRK1 inhibitor compared with tofacitinib. Furthermore, we found two potential PRK1/JAK3-selectivity hotspots. The identified inhibitors and the selectivity hotspots lay the basis for the development of selective PRK1 inhibitors. The identification of PRK1, but also of other cellular tofacitinib targets, has implications on its clinical use and on future development of tofacitinib-like JAK inhibitors. [Formula: see text].

Design, synthesis, and evaluation of 4,6-diaminonicotinamide derivatives as novel and potent immunomodulators targeting JAK3.

PubMed

Nakajima, Yutaka; Aoyama, Naohiro; Takahashi, Fumie; Sasaki, Hiroshi; Hatanaka, Keiko; Moritomo, Ayako; Inami, Masamichi; Ito, Misato; Nakamura, Koji; Nakamori, Fumihiro; Inoue, Takayuki; Shirakami, Shohei

2016-10-01

In organ transplantation, T cell-mediated immune responses play a key role in the rejection of allografts. Janus kinase 3 (JAK3) is specifically expressed in hematopoietic cells and associated with regulation of T cell development via interleukin-2 signaling pathway. Here, we designed novel 4,6-diaminonicotinamide derivatives as immunomodulators targeting JAK3 for prevention of transplant rejection. Our optimization of C4- and C6-substituents and docking calculations to JAK3 protein confirmed that the 4,6-diaminonicotinamide scaffold resulted in potent inhibition of JAK3. We also investigated avoidance of human ether-a-go-go related gene (hERG) inhibitory activity. Selected compound 28 in combination with tacrolimus prevented allograft rejection in a rat heterotopic cardiac transplantation model. Copyright © 2016 Elsevier Ltd. All rights reserved.

Targeting the Oxidative Stress Response System of Fungi with Redox-Potent Chemosensitizing Agents

PubMed Central

Kim, Jong H.; Chan, Kathleen L.; Faria, Natália C. G.; Martins, M. de L.; Campbell, Bruce C.

2012-01-01

The cellular antioxidant system is a target in the antifungal action of amphotericin B (AMB) and itraconazole (ITZ), in filamentous fungi. The sakAΔ mutant of Aspergillus fumigatus, a mitogen-activated protein kinase (MAPK) gene deletion mutant in the antioxidant system, was found to be more sensitive to AMB or ITZ than other A. fumigatus strains, a wild type and a mpkCΔ mutant (a MAPK gene deletion mutant in the polyalcohol sugar utilization system). Complete fungal kill (≥99.9%) by ITZ or AMB was also achieved by much lower dosages for the sakAΔ mutant than for the other strains. It appears msnA, an Aspergillus ortholog to Saccharomyces cerevisiae MSN2 (encoding a stress-responsive C2H2-type zinc-finger regulator) and sakA and/or mpkC (upstream MAPKs) are in the same stress response network under tert-butyl hydroperoxide (t-BuOOH)-, hydrogen peroxide (H2O2)- or AMB-triggered toxicity. Of note is that ITZ-sensitive yeast pathogens were also sensitive to t-BuOOH, showing a connection between ITZ sensitivity and antioxidant capacity of fungi. Enhanced antifungal activity of AMB or ITZ was achieved when these drugs were co-applied with redox-potent natural compounds, 2,3-dihydroxybenzaldehyde, thymol or salicylaldehyde, as chemosensitizing agents. We concluded that redox-potent compounds, which target the antioxidant system in fungi, possess a chemosensitizing capacity to enhance efficacy of conventional drugs. PMID:22438852

Targeted Drug-Carrying Bacteriophages as Antibacterial Nanomedicines▿

PubMed Central

Yacoby, Iftach; Bar, Hagit; Benhar, Itai

2007-01-01

While the resistance of bacteria to traditional antibiotics is a major public health concern, the use of extremely potent antibacterial agents is limited by their lack of selectivity. As in cancer therapy, antibacterial targeted therapy could provide an opportunity to reintroduce toxic substances to the antibacterial arsenal. A desirable targeted antibacterial agent should combine binding specificity, a large drug payload per binding event, and a programmed drug release mechanism. Recently, we presented a novel application of filamentous bacteriophages as targeted drug carriers that could partially inhibit the growth of Staphylococcus aureus bacteria. This partial success was due to limitations of drug-loading capacity that resulted from the hydrophobicity of the drug. Here we present a novel drug conjugation chemistry which is based on connecting hydrophobic drugs to the phage via aminoglycoside antibiotics that serve as solubility-enhancing branched linkers. This new formulation allowed a significantly larger drug-carrying capacity of the phages, resulting in a drastic improvement in their performance as targeted drug-carrying nanoparticles. As an example for a potential systemic use for potent agents that are limited for topical use, we present antibody-targeted phage nanoparticles that carry a large payload of the hemolytic antibiotic chloramphenicol connected through the aminoglycoside neomycin. We demonstrate complete growth inhibition toward the pathogens Staphylococcus aureus, Streptococcus pyogenes, and Escherichia coli with an improvement in potency by a factor of ∼20,000 compared to the free drug. PMID:17404004

When No Response Is a Good Thing | Center for Cancer Research

Cancer.gov

Custom-designed therapies that target cell-surface antigens or receptors represent a promising immunological approach in cancer therapy. Antibodies that bind these targets are the starting point.  Potent toxins can then be added to them by fusing antibody fragments to powerful bacterial toxins such as Pseudomonas exotoxin (PE). This recombinant immunotoxin combines antibody selectivity with toxin cell-killing potency.

Preclinical evaluation of WYE-687, a mTOR kinase inhibitor, as a potential anti-acute myeloid leukemia agent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Feng; Wang, Lingling; Shen, Yunfeng

Mammalian target of rapamycin (mTOR) as a potential drug target for treatment of acute myeloid leukemia (AML). Here, we investigated the potential anti-leukemic activity by WYE-687, a potent mTOR kinase inhibitor. We demonstrated that WYE-687 potently inhibited survival and proliferation of established (HL-60, U937, AML-193 and THP-1 lines) and human AML progenitor cells. Yet, same WYE-687 treatment was non-cytotoxic to the primary peripheral blood mononuclear leukocytes (PBMCs) isolated from healthy donors. WYE-687 induced caspase-dependent apoptotic death in above AML cells/progenitor cells. On the other hand, the pan-caspase inhibitor (Z-VAD-FMK), the caspase-3 specific inhibitor (Z-DEVD-FMK) or the caspase-9 specific inhibitor (z-LEHD-fmk)more » attenuated WYE-687-induced cytotoxicity. At the molecular level, WYE-687 concurrently inhibited activation of mTORC1 (p70S6K1 and S6 phosphorylations) and mTORC2 (AKT Ser-473 and FoxO1/3a phosphorylations), whiling downregulating mTORC1/2-regulated genes (Bcl-xL and hypoxia-inducible factor 1/2α) in both HL-60/U937 cells and human AML progenitor cells. In vivo, oral administration of WYE-687 potently inhibited U937 leukemic xenograft tumor growth in severe combined immunodeficient (SCID) mice, without causing significant toxicities. In summary, our results demonstrate that targeting mTORC1/2 by WYE-687 leads to potent antitumor activity in preclinical models of AML. - Highlights: • WYE-687 inhibits survival and proliferation of human AML cells/progenitor cells. • WYE-687 induces apoptotic death of human AML cells/progenitor cells. • WYE-687 inhibits mTORC1/2 activation in human AML cells/progenitor cells. • WYE-687 inhibits U937 xenograft growth in SCID mice.« less

Targeting the genital tract mucosa with a lipopeptide/recombinant adenovirus prime/boost vaccine induces potent and long-lasting CD8+ T cell immunity against herpes: importance of MyD88.

PubMed

Zhang, Xiuli; Dervillez, Xavier; Chentoufi, Aziz Alami; Badakhshan, Tina; Bettahi, Ilham; Benmohamed, Lbachir

2012-11-01

Targeting of the mucosal immune system of the genital tract with subunit vaccines has failed to induce potent and durable local CD8(+) T cell immunity, which is crucial for protection against many sexually transmitted viral pathogens, including HSV type 2 (HSV-2), which causes genital herpes. In this study, we aimed to investigate the potential of a novel lipopeptide/adenovirus type 5 (Lipo/rAdv5) prime/boost mucosal vaccine for induction of CD8(+) T cell immunity to protect the female genital tract from herpes. The lipopeptide vaccine and the rAdv5 vaccine express the immunodominant HSV-2 CD8(+) T cell epitope (gB(498-505)), and both were delivered intravaginally in the progesterone-induced B6 mouse model of genital herpes. Compared with mice immunized with the homologous lipopeptide/lipopeptide (Lipo/Lipo) vaccine, the Lipo/rAdv5 prime/boost immunized mice 1) developed potent and sustained HSV-specific CD8(+) T cells, detected in both the genital tract draining nodes and in the vaginal mucosa; 2) had significantly lower virus titers; 3) had decreased overt signs of genital herpes disease; and 4) did not succumb to lethal infection (p < 0.005) after intravaginal HSV-2 challenge. Polyfunctional CD8(+) T cells, producing IFN-γ, TNF-α, and IL-2 and exhibiting cytotoxic activity, were associated with protection (p < 0.005). The protective CD8(+) T cell response was significantly compromised in the absence of the adapter MyD88 (p = 0.0001). Taken together, these findings indicate that targeting of the vaginal mucosa with a Lipo/rAdv5 prime/boost vaccine elicits a potent, MyD88-dependent, and long-lasting mucosal CD8(+) T cell protective immunity against sexually transmitted herpes infection and disease.

Targeting the Genital Tract Mucosa with a Lipopeptide/Recombinant Adenovirus Prime/Boost Vaccine Induces Potent and Long-Lasting CD8+ T Cell Immunity Against Herpes: Importance of Myeloid Differentiation Factor 881

PubMed Central

Zhang, Xiuli; Dervillez, Xavier; Chentoufi, Aziz Alami; Badakhshan, Tina; Bettahi, Ilham; BenMohamed, Lbachir

2012-01-01

Targeting the mucosal immune system of the genital tract (GT) with subunit vaccines failed to induce potent and durable local CD8+ T cell immunity, crucial for protection against many sexually transmitted viral (STV) pathogens, including herpes simplex virus type 2 (HSV-2) that causes genital herpes. In this study, we aimed to investigate the potential of a novel lipopeptide/adenovirus type 5 (Lipo/rAdv5) prime/boost mucosal vaccine for induction of CD8+ T cell immunity to protect the female genital tract from herpes. The lipopeptide and the rAdv5 vaccine express the immunodominant HSV-2 CD8+ T cell epitope (gB498-505) and both were delivered intravaginally (IVAG) in the progesterone-induced B6 mouse model of genital herpes. Compared to its homologous lipopeptide/lipopeptide (Lipo/Lipo); the Lipo/rAdv5 prime/boost immunized mice: (i) developed potent and sustained HSV-specific CD8+ T cells, detected in both the GT draining nodes (GT-DLN) and in the vaginal mucosa (VM); (ii) had significantly lower virus titers; (iii) had decreased overt signs of genital herpes disease; and (iv) did not succumb to lethal infection (p < 0.005), following intravaginal HSV-2 challenge. Polyfunctional CD8+ T cells, producing IFN-γ, TNF-α and IL-2 and exhibiting cytotoxic activity, were associated with protection (p < 0.005). The protective CD8+ T cell response was significantly compromised in the absence of the adaptor myeloid differentiation factor 88 (MyD88) (p = 0.0001). Taken together, these findings indicate that targeting the VM with a Lipo/rAdv5 prime/boost vaccine elicits a potent, MyD88-dependent, and long-lasting mucosal CD8+ T cell protective immunity against sexually transmitted herpes infection and disease. PMID:23018456

Structure based drug design: development of potent and selective factor IXa (FIXa) inhibitors.

PubMed

Wang, Shouming; Beck, Richard; Burd, Andrew; Blench, Toby; Marlin, Frederic; Ayele, Tenagne; Buxton, Stuart; Dagostin, Claudio; Malic, Maja; Joshi, Rina; Barry, John; Sajad, Mohammed; Cheung, Chiming; Shaikh, Shaheda; Chahwala, Suresh; Chander, Chaman; Baumgartner, Christine; Holthoff, Hans-Peter; Murray, Elizabeth; Blackney, Michael; Giddings, Amanda

2010-02-25

On the basis of our understanding on the binding interactions of the benzothiophene template within the FIXa active site by X-ray crystallography and molecular modeling studies, we developed our SAR strategy by targeting the 4-position of the template to access the S1 beta and S2-S4 sites. A number of highly selective and potent factor Xa (FXa) and FIXa inhibitors were identified by simple switch of functional groups with conformational changes toward the S2-S4 sites.

Discovery of a Potent Free Fatty Acid 1 Receptor Agonist with Low Lipophilicity, Low Polar Surface Area, and Robust in Vivo Efficacy.

PubMed

Hansen, Steffen V F; Christiansen, Elisabeth; Urban, Christian; Hudson, Brian D; Stocker, Claire J; Due-Hansen, Maria E; Wargent, Ed T; Shimpukade, Bharat; Almeida, Reinaldo; Ejsing, Christer S; Cawthorne, Michael A; Kassack, Matthias U; Milligan, Graeme; Ulven, Trond

2016-03-24

The free fatty acid receptor 1 (FFA1 or GPR40) is established as an interesting potential target for treatment of type 2 diabetes. However, to obtain optimal ligands, it may be necessary to limit both lipophilicity and polar surface area, translating to a need for small compounds. We here describe the identification of 24, a potent FFA1 agonist with low lipophilicity and very high ligand efficiency that exhibit robust glucose lowering effect.

Development of a potent and selective FLT3 kinase inhibitor by systematic expansion of a non-selective fragment-screening hit.

PubMed

Nakano, Hirofumi; Hasegawa, Tsukasa; Imamura, Riyo; Saito, Nae; Kojima, Hirotatsu; Okabe, Takayoshi; Nagano, Tetsuo

2016-05-01

A non-selective inhibitor (1) of FMS-like tyrosine kinase-3 (FLT3) was identified by fragment screening and systematically modified to afford a potent and selective inhibitor 26. We confirmed that 26 inhibited the growth of FLT-3-activated human acute myeloid leukemia cell line MV4-11. Our design strategy enabled rapid development of a novel type of FLT3 inhibitor from the hit fragment in the absence of target-structural information. Copyright © 2016 Elsevier Ltd. All rights reserved.

High Throughput Ambient Mass Spectrometric Approach to Species Identification and Classification from Chemical Fingerprint Signatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Musah, Rabi A.; Espinoza, Edgard O.; Cody, Robert B.

A high throughput method for species identification and classification through chemometric processing of direct analysis in real time (DART) mass spectrometry-derived fingerprint signatures has been developed. The method entails introduction of samples to the open air space between the DART ion source and the mass spectrometer inlet, with the entire observed mass spectral fingerprint subjected to unsupervised hierarchical clustering processing. Moreover, a range of both polar and non-polar chemotypes are instantaneously detected. The result is identification and species level classification based on the entire DART-MS spectrum. In this paper, we illustrate how the method can be used to: (1) distinguishmore » between endangered woods regulated by the Convention for the International Trade of Endangered Flora and Fauna (CITES) treaty; (2) assess the origin and by extension the properties of biodiesel feedstocks; (3) determine insect species from analysis of puparial casings; (4) distinguish between psychoactive plants products; and (5) differentiate between Eucalyptus species. An advantage of the hierarchical clustering approach to processing of the DART-MS derived fingerprint is that it shows both similarities and differences between species based on their chemotypes. Furthermore, full knowledge of the identities of the constituents contained within the small molecule profile of analyzed samples is not required.« less

High Throughput Ambient Mass Spectrometric Approach to Species Identification and Classification from Chemical Fingerprint Signatures

DOE PAGES

Musah, Rabi A.; Espinoza, Edgard O.; Cody, Robert B.; ...

2015-07-09

A high throughput method for species identification and classification through chemometric processing of direct analysis in real time (DART) mass spectrometry-derived fingerprint signatures has been developed. The method entails introduction of samples to the open air space between the DART ion source and the mass spectrometer inlet, with the entire observed mass spectral fingerprint subjected to unsupervised hierarchical clustering processing. Moreover, a range of both polar and non-polar chemotypes are instantaneously detected. The result is identification and species level classification based on the entire DART-MS spectrum. In this paper, we illustrate how the method can be used to: (1) distinguishmore » between endangered woods regulated by the Convention for the International Trade of Endangered Flora and Fauna (CITES) treaty; (2) assess the origin and by extension the properties of biodiesel feedstocks; (3) determine insect species from analysis of puparial casings; (4) distinguish between psychoactive plants products; and (5) differentiate between Eucalyptus species. An advantage of the hierarchical clustering approach to processing of the DART-MS derived fingerprint is that it shows both similarities and differences between species based on their chemotypes. Furthermore, full knowledge of the identities of the constituents contained within the small molecule profile of analyzed samples is not required.« less

Chemical composition and therapeutic effects of Lippia alba (Mill.) N. E. Brown leaves hydro-alcoholic extract in patients with migraine.

PubMed

Conde, Raul; Corrêa, Valéria S C; Carmona, Fabio; Contini, Silvia H T; Pereira, Ana M S

2011-11-15

There is no universally accepted and effective prophylaxis of migraine headache episodes. Thus we aimed to investigate the effects of Lippia alba (Mill.) N. E. Brown, an herb with many effects on central nervous system, on pain frequency and intensity of migraine patients. Patients were enrolled in a prospective, phase 2, non-controlled cohort study to orally receive hydro-alcoholic extract of L. alba leaves. Headache intensity and frequency of episodes were recorded before and after 30-60 days of treatment. We also studied the chemical composition of its essential oil by gas chromatography-mass spectrometry. We described for the first time a particular L. alba chemotype with geranial and carvenone as major compounds. With treatment, both frequency and intensity of pain episodes significantly decreased from baseline to first reassessment date. More than 80% of patients experienced a minimum 50% reduction on pain intensity and frequency. No side effects were reported. Treatment with a geranial plus carvenone chemotype of L. alba hydro-alcoholic extract is a cheap, widely available, highly effective therapy to reduce both the intensity and the frequency of headache episodes of migraine patients with no side effects. Copyright © 2011 Elsevier GmbH. All rights reserved.

A High Throughput Ambient Mass Spectrometric Approach to Species Identification and Classification from Chemical Fingerprint Signatures

PubMed Central

Musah, Rabi A.; Espinoza, Edgard O.; Cody, Robert B.; Lesiak, Ashton D.; Christensen, Earl D.; Moore, Hannah E.; Maleknia, Simin; Drijfhout, Falko P.

2015-01-01

A high throughput method for species identification and classification through chemometric processing of direct analysis in real time (DART) mass spectrometry-derived fingerprint signatures has been developed. The method entails introduction of samples to the open air space between the DART ion source and the mass spectrometer inlet, with the entire observed mass spectral fingerprint subjected to unsupervised hierarchical clustering processing. A range of both polar and non-polar chemotypes are instantaneously detected. The result is identification and species level classification based on the entire DART-MS spectrum. Here, we illustrate how the method can be used to: (1) distinguish between endangered woods regulated by the Convention for the International Trade of Endangered Flora and Fauna (CITES) treaty; (2) assess the origin and by extension the properties of biodiesel feedstocks; (3) determine insect species from analysis of puparial casings; (4) distinguish between psychoactive plants products; and (5) differentiate between Eucalyptus species. An advantage of the hierarchical clustering approach to processing of the DART-MS derived fingerprint is that it shows both similarities and differences between species based on their chemotypes. Furthermore, full knowledge of the identities of the constituents contained within the small molecule profile of analyzed samples is not required. PMID:26156000

A High Throughput Ambient Mass Spectrometric Approach to Species Identification and Classification from Chemical Fingerprint Signatures

NASA Astrophysics Data System (ADS)

Musah, Rabi A.; Espinoza, Edgard O.; Cody, Robert B.; Lesiak, Ashton D.; Christensen, Earl D.; Moore, Hannah E.; Maleknia, Simin; Drijfhout, Falko P.

2015-07-01

A high throughput method for species identification and classification through chemometric processing of direct analysis in real time (DART) mass spectrometry-derived fingerprint signatures has been developed. The method entails introduction of samples to the open air space between the DART ion source and the mass spectrometer inlet, with the entire observed mass spectral fingerprint subjected to unsupervised hierarchical clustering processing. A range of both polar and non-polar chemotypes are instantaneously detected. The result is identification and species level classification based on the entire DART-MS spectrum. Here, we illustrate how the method can be used to: (1) distinguish between endangered woods regulated by the Convention for the International Trade of Endangered Flora and Fauna (CITES) treaty; (2) assess the origin and by extension the properties of biodiesel feedstocks; (3) determine insect species from analysis of puparial casings; (4) distinguish between psychoactive plants products; and (5) differentiate between Eucalyptus species. An advantage of the hierarchical clustering approach to processing of the DART-MS derived fingerprint is that it shows both similarities and differences between species based on their chemotypes. Furthermore, full knowledge of the identities of the constituents contained within the small molecule profile of analyzed samples is not required.

Highly Stereoselective Synthesis of a Compound Collection Based on the Bicyclic Scaffolds of Natural Products.

PubMed

Annamalai, Murali; Hristeva, Stanimira; Bielska, Martyna; Ortega, Raquel; Kumar, Kamal

2017-05-18

Despite the great contribution of natural products in the history of successful drug discovery, there are significant limitations that persuade the pharmaceutical industry to evade natural products in drug discovery research. The extreme scarcity as well as structural complexity of natural products renders their practical synthetic access and further modifications extremely challenging. Although other alternative technologies, particularly combinatorial chemistry, were embraced by the pharmaceutical industry to get quick access to a large number of small molecules with simple frameworks that often lack three-dimensional complexity, hardly any success was achieved in the discovery of lead molecules. To acquire chemotypes beholding structural features of natural products, for instance high sp ³ character, the synthesis of compound collections based on core-scaffolds of natural products presents a promising strategy. Here, we report a natural product inspired synthesis of six different chemotypes and their derivatives for drug discovery research. These bicyclic hetero- and carbocyclic scaffolds are highly novel, rich in sp ³ features and with ideal physicochemical properties to display drug likeness. The functional groups on the scaffolds were exploited further to generate corresponding compound collections. Synthesis of two of these collections exemplified with ca. 350 compounds are each also presented. The whole compound library is being exposed to various biological screenings within the European Lead Factory consortium.

Chemical Polymorphism of Origanum compactum Grown in All Natural Habitats in Morocco.

PubMed

Aboukhalid, Kaoutar; Lamiri, Abdeslam; Agacka-Mołdoch, Monika; Doroszewska, Teresa; Douaik, Ahmed; Bakha, Mohamed; Casanova, Joseph; Tomi, Félix; Machon, Nathalie; Faiz, Chaouki Al

2016-09-01

Origanum compactum L. (Lamiaceae) is one of the most important medicinal species in term of ethnobotany in Morocco. It is considered as a very threatened species as it is heavily exploited. Its domestication remains the most efficient way to safeguard it for future generations. For this purpose, wide evaluation of the existing variability in all over the Moroccan territory is required. The essential oils of 527 individual plants belonging to 88 populations collected from the whole distribution area of the species in Morocco were analyzed by GC/MS. The dominant constituents were carvacrol (0 - 96.3%), thymol (0 - 80.7%), p-cymene (0.2 - 58.6%), γ-terpinene (0 - 35.2%), carvacryl methyl ether (0 - 36.2%), and α-terpineol (0 - 25.8%). While in the Middle Atlas region and the Central Morocco mainly carvacrol type samples were found, much higher chemotypic diversity was encountered within samples from the north part of Morocco (occidental and central Rif regions). The high chemical polymorphism of plants offers a wide range for selection of valuable chemotypes, as a part of breeding and domestication programs of this threatened species. © 2016 Wiley-VHCA AG, Zürich.

Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects

PubMed Central

Russo, Ethan B

2011-01-01

Tetrahydrocannabinol (THC) has been the primary focus of cannabis research since 1964, when Raphael Mechoulam isolated and synthesized it. More recently, the synergistic contributions of cannabidiol to cannabis pharmacology and analgesia have been scientifically demonstrated. Other phytocannabinoids, including tetrahydrocannabivarin, cannabigerol and cannabichromene, exert additional effects of therapeutic interest. Innovative conventional plant breeding has yielded cannabis chemotypes expressing high titres of each component for future study. This review will explore another echelon of phytotherapeutic agents, the cannabis terpenoids: limonene, myrcene, α-pinene, linalool, β-caryophyllene, caryophyllene oxide, nerolidol and phytol. Terpenoids share a precursor with phytocannabinoids, and are all flavour and fragrance components common to human diets that have been designated Generally Recognized as Safe by the US Food and Drug Administration and other regulatory agencies. Terpenoids are quite potent, and affect animal and even human behaviour when inhaled from ambient air at serum levels in the single digits ng·mL−1. They display unique therapeutic effects that may contribute meaningfully to the entourage effects of cannabis-based medicinal extracts. Particular focus will be placed on phytocannabinoid-terpenoid interactions that could produce synergy with respect to treatment of pain, inflammation, depression, anxiety, addiction, epilepsy, cancer, fungal and bacterial infections (including methicillin-resistant Staphylococcus aureus). Scientific evidence is presented for non-cannabinoid plant components as putative antidotes to intoxicating effects of THC that could increase its therapeutic index. Methods for investigating entourage effects in future experiments will be proposed. Phytocannabinoid-terpenoid synergy, if proven, increases the likelihood that an extensive pipeline of new therapeutic products is possible from this venerable plant. LINKED ARTICLES This article is part of a themed issue on Cannabinoids in Biology and Medicine. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2011.163.issue-7 PMID:21749363

Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects.

PubMed

Russo, Ethan B

2011-08-01

Tetrahydrocannabinol (THC) has been the primary focus of cannabis research since 1964, when Raphael Mechoulam isolated and synthesized it. More recently, the synergistic contributions of cannabidiol to cannabis pharmacology and analgesia have been scientifically demonstrated. Other phytocannabinoids, including tetrahydrocannabivarin, cannabigerol and cannabichromene, exert additional effects of therapeutic interest. Innovative conventional plant breeding has yielded cannabis chemotypes expressing high titres of each component for future study. This review will explore another echelon of phytotherapeutic agents, the cannabis terpenoids: limonene, myrcene, α-pinene, linalool, β-caryophyllene, caryophyllene oxide, nerolidol and phytol. Terpenoids share a precursor with phytocannabinoids, and are all flavour and fragrance components common to human diets that have been designated Generally Recognized as Safe by the US Food and Drug Administration and other regulatory agencies. Terpenoids are quite potent, and affect animal and even human behaviour when inhaled from ambient air at serum levels in the single digits ng·mL(-1) . They display unique therapeutic effects that may contribute meaningfully to the entourage effects of cannabis-based medicinal extracts. Particular focus will be placed on phytocannabinoid-terpenoid interactions that could produce synergy with respect to treatment of pain, inflammation, depression, anxiety, addiction, epilepsy, cancer, fungal and bacterial infections (including methicillin-resistant Staphylococcus aureus). Scientific evidence is presented for non-cannabinoid plant components as putative antidotes to intoxicating effects of THC that could increase its therapeutic index. Methods for investigating entourage effects in future experiments will be proposed. Phytocannabinoid-terpenoid synergy, if proven, increases the likelihood that an extensive pipeline of new therapeutic products is possible from this venerable plant. http://dx.doi.org/10.1111/bph.2011.163.issue-7. © 2011 The Author. British Journal of Pharmacology © 2011 The British Pharmacological Society.

P2X-selective purinergic antagonists are strong inhibitors of HIV-1 fusion during both cell-to-cell and cell-free infection.

PubMed

Swartz, Talia H; Esposito, Anthony M; Durham, Natasha D; Hartmann, Boris M; Chen, Benjamin K

2014-10-01

Human immunodeficiency virus type 1 (HIV-1) infection is chronic and presently still incurable. Antiretroviral drugs effectively suppress replication; however, persistent activation of inflammatory pathways remains a key cause of morbidity. Recent studies proposed that purinergic signaling is required for HIV-1 infection. Purinergic receptors are distributed throughout a wide variety of tissue types and detect extracellular ATP as a danger signal released from dying cells. We have explored how these pathways are involved in the transmission of HIV-1 from cell to cell through virological synapses. Infection of CD4+ T lymphocytes with HIV-1 in the presence of an inhibitor of P2X receptors effectively inhibited HIV-1 infection through both cell-free and cell-to-cell contact in a dose-dependent manner. Inhibition of direct cell-to-cell infection did not affect the formation of virological synapses or the subsequent cell-to-cell transfer of HIV-1. During both cell-free and cell-to-cell CD4+ T lymphocyte infection, purinergic antagonists blocked infection at the level of viral membrane fusion. During cell-to-cell transmission, we observed CXCR4 colocalization with the newly internalized virus particles within target lymphocytes and found that the purinergic antagonists did not impair the recruitment of the coreceptor CXCR4 to the site of Gag internalization in the target cell. In a screen of a library of purinergic antagonists, we found that the most potent inhibitors of HIV-1 fusion were those that target P2X receptors, while P2Y-selective receptor antagonists or adenosine receptor antagonists were ineffective. Our results suggest that P2X receptors may provide a therapeutic target and that purinergic antagonists may have potent activity against viral infection of CD4+ T lymphocytes by both cell-free and cell-to-cell transmission. This study identifies purinergic antagonists to be potent inhibitors of HIV-1 cell-free and cell-to-cell-mediated infection and provides a stepwise determination of when these compounds inhibit HIV-1 infection. These data provide a rationale for the development of novel antiretroviral therapies that have a dual role in both direct antiviral activity and the reduction of HIV-associated inflammation. Purinergic antagonists are shown here to have equivalent efficacy in inhibiting HIV infection via cell-free and cell-to-cell infection, and it is shown that purinergic receptors could provide an attractive therapeutic anti-HIV target that might avoid resistance by targeting a host signaling pathway that potently regulates HIV infection. The high-throughput screen of HIV-1 fusion inhibitors further defines P2X-selective compounds among the purinergic compounds as being the most potent HIV entry inhibitors. Clinical studies on these drugs for other inflammatory indications suggest that they are safe, and thus, if developed for use as anti-HIV agents, they could reduce both HIV replication and HIV-related inflammation. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Fragment Linking and Optimization of Inhibitors of the Aspartic Protease Endothiapepsin: Fragment-Based Drug Design Facilitated by Dynamic Combinatorial Chemistry.

PubMed

Mondal, Milon; Radeva, Nedyalka; Fanlo-Virgós, Hugo; Otto, Sijbren; Klebe, Gerhard; Hirsch, Anna K H

2016-08-01

Fragment-based drug design (FBDD) affords active compounds for biological targets. While there are numerous reports on FBDD by fragment growing/optimization, fragment linking has rarely been reported. Dynamic combinatorial chemistry (DCC) has become a powerful hit-identification strategy for biological targets. We report the synergistic combination of fragment linking and DCC to identify inhibitors of the aspartic protease endothiapepsin. Based on X-ray crystal structures of endothiapepsin in complex with fragments, we designed a library of bis-acylhydrazones and used DCC to identify potent inhibitors. The most potent inhibitor exhibits an IC50 value of 54 nm, which represents a 240-fold improvement in potency compared to the parent hits. Subsequent X-ray crystallography validated the predicted binding mode, thus demonstrating the efficiency of the combination of fragment linking and DCC as a hit-identification strategy. This approach could be applied to a range of biological targets, and holds the potential to facilitate hit-to-lead optimization. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

The effect of oxidant on resputtering of Bi from Bi-Sr-Ca-Cu-O films

NASA Astrophysics Data System (ADS)

Grace, J. M.; McDonald, D. B.; Reiten, M. T.; Olson, J.; Kampwirth, R. T.; Gray, K. E.

1991-09-01

The type and partial pressure of oxidant mixed with argon can affect the selective resputtering of Bi in composite-target, magnetron-sputtered Bi-Sr-Ca-Cu-O films. Comparative studies using oxygen and ozone show that ozone is a more potent oxidant, as well as a more potent source of resputterers, than is oxygen. Severe resputtering from ozone is significantly reduced by a -40 V potential on the sample block. We suggest that oxygen causes resputtering by forming O2(+)p , which interacts with the target to produce energetic O(-). In contrast, ozone may form lower-energy O(-) by electron impact in the dark space. Negative oxygen ions from the target itself may be responsible for a background resputtering effect. Our results and those found for Y-Ba-Cu-O by others are comparable. Bi in Bi-Sr-Ca-Cu-O behaves as Ba in Y-Ba-Cu-O, with regard to selective resputtering; furthermore, the response of Sr, Ca, and Cu to oxygen in sputtered Bi-Sr-Ca-Cu-O is similar to what is observed for Cu in Y-Ba-Cu-O.

Design, Synthesis, and Pharmacokinetics of a Bone-Targeting Dual-Action Prodrug for the Treatment of Osteoporosis.

PubMed

Xie, Haibo; Chen, Gang; Young, Robert N

2017-08-24

A dual-action bone-targeting prodrug has been designed, synthesized, and evaluated for in vitro and in vivo metabolic stability, in vivo tissue distribution, and rates of release of the active constituents after binding to bones through the use of differentially double-labeled derivatives. The conjugate (general structure 7) embodies the merger of a very potent and proven anabolic selective agonist of the prostaglandin EP4 receptor, compound 5, and alendronic acid, a potent inhibitor of bone resorption, optimally linked through a differentially hydrolyzable linker unit, N-4-carboxymethylphenyl-methyloxycarbonyl-leucinyl-argininyl-para-aminophenylmethylalcohol (Leu-Arg-PABA). Optimized conjugate 16 was designed so that esterase activity will liberate 5 and cathepsin K cleavage of the Leu-Arg-PABA element will liberate alendronic acid. Studies with doubly radiolabeled 16 provide a proof-of-concept for the use of a cathepsin K cleavable peptide-linked conjugate for targeting of bisphosphonate prodrugs to bone and slow release liberation of the active constituents in vivo. Such conjugates are potential therapies for the treatment of bone disorders such as osteoporosis.

1H-NMR and UPLC-MS metabolomics: Functional tools for exploring chemotypic variation in Sceletium tortuosum from two provinces in South Africa.

PubMed

Zhao, Jianping; Khan, Ikhlas A; Combrinck, Sandra; Sandasi, Maxleene; Chen, Weiyang; Viljoen, Alvaro M

2018-05-17

Sceletium tortuosum (Aizoaceae) is widely recognised for the treatment of stress, anxiety and depression, as well as for obsessive compulsive disorders. A comprehensive intraspecies chemotypic variation study, using samples harvested from two distinct regions of South Africa, was done using both proton nuclear magnetic resonance ( 1 H-NMR) spectroscopy of methanol extracts (N = 145) and ultra performance liquid chromatography-mass spectrometry (UPLC-MS) of acid/base extracts (N = 289). Chemometric analysis of the 1 H-NMR data indicated two main clusters that were region-specific (Northern Cape and Western Cape provinces). Two dimensional (2D) NMR was used to identify analytes that contributed to the clustering as revealed by the S-plot. The sceletium alkaloids, pinitol and two alkylamines, herein reported for the first time from S. tortuosum, were identified as markers that distinguished the two groups. Relative quantification of the marker analytes conducted by qNMR indicated that samples from the Northern Cape generally contained higher concentrations of all the markers than samples from the Western Cape. Quantitative analysis of the four mesembrine alkaloids using a validated UPLC-photo diode array (PDA) detection method confirmed the results of qNMR with regard to the total alkaloid concentrations. Samples from the Northern Cape Province were found to contain, on average, very high total alkaloids, ranging from 4938.0 to 9376.8 mg/kg dry w. Regarding the Western Cape samples, the total yields of the four mesembrine alkaloids were substantially lower (averages 16.4-4143.2 mg/kg). Hierarchical cluster analysis of the UPLC-MS data, based on the alkaloid chemistry, revealed three branches, with one branch comprising samples primarily from the Northern Cape that seemed somewhat chemically conserved, while the other two branches represented mainly samples from the Western Cape. The construction of an orthogonal projections to latent structures-discriminant analysis model and subsequent loadings plot, allowed alkaloid markers to be identified for each cluster. The diverse sceletium alkaloid chemistry of samples from the three clusters may facilitate the recognition of alkaloid profiles, rather than individual compounds, that exert targeted effects on various brain receptors involved in stress, anxiety or depression. Copyright © 2018 Elsevier Ltd. All rights reserved.

Targeting Alpha5 Beta1 Integrin to Prevent Metastatic Breast Cancer Cell Invasion: PhScN Target Site Definition and Plasma Stability

DTIC Science & Technology

2013-09-01

12192595 12. Yao, H., D. Veine, K. Fay, E. Staszewski, et al., The PHSCN dendrimer as a more potent inhibitor of human breast cancer cell...Z.Z. Zeng, K.S. Fay, et al., Increased potency of the PHSCN dendrimer as an inhibitor of human prostate cancer cell invasion, extravasation, and lung

Targeting Alpha5 Beta1 Integrin to Prevent Metastatic Breast Cancer Cell Invasion: PhScN Target Site Definition and Plasma Stability

DTIC Science & Technology

2014-09-01

dendrimer as a more potent inhibitor of human breast cancer cell invasion, extravasation, and lung colony formation. Breast Cancer Research and Treatment...2011. 125: p. 363-375. PMID: 20300829 13. Yao, H., D.M. Veine, Z.Z. Zeng, K.S. Fay, et al., Increased potency of the PHSCN dendrimer as an inhibitor of

Discovery of PF-04620110, a Potent, Selective, and Orally Bioavailable Inhibitor of DGAT-1

PubMed Central

2011-01-01

Acyl-CoA:diacylglycerol acyltransferase-1 (DGAT-1) catalyzes the final committed step in the biosynthesis of triglycerides. DGAT-1 knockout mice have been shown to be resistant to diet-induced obesity and have increased insulin sensitivity. Thus, inhibition of DGAT-1 may represent an attractive target for the treatment of obesity or type II diabetes. Herein, we report the discovery and characterization of a potent and selective DGAT-1 inhibitor PF-04620110 (3). Compound 3 inhibits DGAT-1 with an IC50 of 19 nM and shows high selectivity versus a broad panel of off-target pharmacologic end points. In vivo DGAT-1 inhibition has been demonstrated through reduction of plasma triglyceride levels in rodents at doses of ≥0.1 mg/kg following a lipid challenge. On the basis of this pharmacologic and pharmacokinetic profile, compound 3 has been advanced to human clinical studies. PMID:24900321

Discovery of PF-04620110, a Potent, Selective, and Orally Bioavailable Inhibitor of DGAT-1.

PubMed

Dow, Robert L; Li, Jian-Cheng; Pence, Michael P; Gibbs, E Michael; LaPerle, Jennifer L; Litchfield, John; Piotrowski, David W; Munchhof, Michael J; Manion, Tara B; Zavadoski, William J; Walker, Gregory S; McPherson, R Kirk; Tapley, Susan; Sugarman, Eliot; Guzman-Perez, Angel; DaSilva-Jardine, Paul

2011-05-12

Acyl-CoA:diacylglycerol acyltransferase-1 (DGAT-1) catalyzes the final committed step in the biosynthesis of triglycerides. DGAT-1 knockout mice have been shown to be resistant to diet-induced obesity and have increased insulin sensitivity. Thus, inhibition of DGAT-1 may represent an attractive target for the treatment of obesity or type II diabetes. Herein, we report the discovery and characterization of a potent and selective DGAT-1 inhibitor PF-04620110 (3). Compound 3 inhibits DGAT-1 with an IC50 of 19 nM and shows high selectivity versus a broad panel of off-target pharmacologic end points. In vivo DGAT-1 inhibition has been demonstrated through reduction of plasma triglyceride levels in rodents at doses of ≥0.1 mg/kg following a lipid challenge. On the basis of this pharmacologic and pharmacokinetic profile, compound 3 has been advanced to human clinical studies.

Discovery of multi-target receptor tyrosine kinase inhibitors as novel anti-angiogenesis agents

NASA Astrophysics Data System (ADS)

Wang, Jinfeng; Zhang, Lin; Pan, Xiaoyan; Dai, Bingling; Sun, Ying; Li, Chuansheng; Zhang, Jie

2017-03-01

Recently, we have identified a biphenyl-aryl urea incorporated with salicylaldoxime (BPS-7) as an anti-angiogenesis agent. Herein, we disclosed a series of novel anti-angiogenesis agents with BPS-7 as lead compound through combining diarylureas with N-pyridin-2-ylcyclopropane carboxamide. Several title compounds exhibited simultaneous inhibition effects against three pro-angiogenic RTKs (VEGFR-2, TIE-2 and EphB4). Some of them displayed potent anti-proliferative activity against human vascular endothelial cell (EA.hy926). In particular, two potent compounds (CDAU-1 and CDAU-2) could be considered as promising anti-angiogenesis agents with triplet inhibition profile. The biological evaluation and molecular docking results indicate that N-pyridin-2-ylcyclopropane carboxamide could serve as a hinge-binding group (HBG) for the discovery of multi-target anti-angiogenesis agents. CDAU-2 also exhibited promising anti-angiogenic potency in a tissue model for angiogenesis.

The Curcumin Analog C-150, Influencing NF-κB, UPR and Akt/Notch Pathways Has Potent Anticancer Activity In Vitro and In Vivo

PubMed Central

Hackler, László; Ózsvári, Béla; Gyuris, Márió; Sipos, Péter; Fábián, Gabriella; Molnár, Eszter; Marton, Annamária; Faragó, Nóra; Mihály, József; Nagy, Lajos István; Szénási, Tibor; Diron, Andrea; Párducz, Árpád; Kanizsai, Iván; Puskás, László G.

2016-01-01

C-150 a Mannich-type curcumin derivative, exhibited pronounced cytotoxic effects against eight glioma cell lines at micromolar concentrations. Inhibition of cell proliferation by C-150 was mediated by affecting multiple targets as confirmed at transcription and protein level. C-150 effectively reduced the transcription activation of NFkB, inhibited PKC-alpha which are constitutively over-expressed in glioblastoma. The effects of C-150 on the Akt/ Notch signaling were also demonstrated in a Drosophila tumorigenesis model. C-150 reduced the number of tumors in Drosophila with similar efficacy to mitoxantrone. In an in vivo orthotopic glioma model, C-150 significantly increased the median survival of treated nude rats compared to control animals. The multi-target action of C-150, and its preliminary in vivo efficacy would render this curcumin analogue as a potent clinical candidate against glioblastoma. PMID:26943907

Isolation of potent neutralizing antibodies from a survivor of the 2014 Ebola virus outbreak.

PubMed

Bornholdt, Zachary A; Turner, Hannah L; Murin, Charles D; Li, Wen; Sok, Devin; Souders, Colby A; Piper, Ashley E; Goff, Arthur; Shamblin, Joshua D; Wollen, Suzanne E; Sprague, Thomas R; Fusco, Marnie L; Pommert, Kathleen B J; Cavacini, Lisa A; Smith, Heidi L; Klempner, Mark; Reimann, Keith A; Krauland, Eric; Gerngross, Tillman U; Wittrup, Karl D; Saphire, Erica Ollmann; Burton, Dennis R; Glass, Pamela J; Ward, Andrew B; Walker, Laura M

2016-03-04

Antibodies targeting the Ebola virus surface glycoprotein (EBOV GP) are implicated in protection against lethal disease, but the characteristics of the human antibody response to EBOV GP remain poorly understood. We isolated and characterized 349 GP-specific monoclonal antibodies (mAbs) from the peripheral B cells of a convalescent donor who survived the 2014 EBOV Zaire outbreak. Remarkably, 77% of the mAbs neutralize live EBOV, and several mAbs exhibit unprecedented potency. Structures of selected mAbs in complex with GP reveal a site of vulnerability located in the GP stalk region proximal to the viral membrane. Neutralizing antibodies targeting this site show potent therapeutic efficacy against lethal EBOV challenge in mice. The results provide a framework for the design of new EBOV vaccine candidates and immunotherapies. Copyright © 2016, American Association for the Advancement of Science.

Converting One-Face α-Helix Mimetics into Amphiphilic α-Helix Mimetics as Potent Inhibitors of Protein-Protein Interactions.

PubMed

Lee, Ji Hoon; Oh, Misook; Kim, Hyun Soo; Lee, Huisun; Im, Wonpil; Lim, Hyun-Suk

2016-01-11

Many biologically active α-helical peptides adopt amphiphilic helical structures that contain hydrophobic residues on one side and hydrophilic residues on the other side. Therefore, α-helix mimetics capable of mimicking such amphiphilic helical peptides should possess higher binding affinity and specificity to target proteins. Here we describe an efficient method for generating amphiphilic α-helix mimetics. One-face α-helix mimetics having hydrophobic side chains on one side was readily converted into amphiphilic α-helix mimetics by introducing appropriate charged residues on the opposite side. We also demonstrate that such two-face amphiphilic α-helix mimetics indeed show remarkably improved binding affinity to a target protein, compared to one-face hydrophobic α-helix mimetics. We believe that generating a large combinatorial library of these amphiphilic α-helix mimetics can be valuable for rapid discovery of highly potent and specific modulators of protein-protein interactions.

Targeted and Nontargeted α-Particle Therapies.

PubMed

McDevitt, Michael R; Sgouros, George; Sofou, Stavroula

2018-06-04

α-Particle irradiation of cancerous tissue is increasingly recognized as a potent therapeutic option. We briefly review the physics, radiobiology, and dosimetry of α-particle emitters, as well as the distinguishing features that make them unique for radiopharmaceutical therapy. We also review the emerging clinical role of α-particle therapy in managing cancer and recent studies on in vitro and preclinical α-particle therapy delivered by antibodies, other small molecules, and nanometer-sized particles. In addition to their unique radiopharmaceutical characteristics, the increased availability and improved radiochemistry of α-particle radionuclides have contributed to the growing recent interest in α-particle radiotherapy. Targeted therapy strategies have presented novel possibilities for the use of α-particles in the treatment of cancer. Clinical experience has already demonstrated the safe and effective use of α-particle emitters as potent tumor-selective drugs for the treatment of leukemia and metastatic disease.

Targeted and Nontargeted α-Particle Therapies

PubMed Central

McDevitt, Michael R.; Sgouros, George; Sofou, Stavroula

2018-01-01

α-Particle irradiation of cancerous tissue is increasingly recognized as a potent therapeutic option. We briefly review the physics, radiobiology, and dosimetry of α-particle emitters, as well as the distinguishing features that make them unique for radiopharmaceutical therapy. We also review the emerging clinical role of α-particle therapy in managing cancer and recent studies on in vitro and preclinical α-particle therapy delivered by antibodies, other small molecules, and nanometer-sized particles. In addition to their unique radiopharmaceutical characteristics, the increased availability and improved radiochemistry of α-particle radionuclides have contributed to the growing recent interest in α-particle radiotherapy. Targeted therapy strategies have presented novel possibilities for the use of α-particles in the treatment of cancer. Clinical experience has already demonstrated the safe and effective use of α-particle emitters as potent tumor-selective drugs for the treatment of leukemia and metastatic disease. PMID:29345977

Discovery of multi-target receptor tyrosine kinase inhibitors as novel anti-angiogenesis agents

PubMed Central

Wang, Jinfeng; Zhang, Lin; Pan, Xiaoyan; Dai, Bingling; Sun, Ying; Li, Chuansheng; Zhang, Jie

2017-01-01

Recently, we have identified a biphenyl-aryl urea incorporated with salicylaldoxime (BPS-7) as an anti-angiogenesis agent. Herein, we disclosed a series of novel anti-angiogenesis agents with BPS-7 as lead compound through combining diarylureas with N-pyridin-2-ylcyclopropane carboxamide. Several title compounds exhibited simultaneous inhibition effects against three pro-angiogenic RTKs (VEGFR-2, TIE-2 and EphB4). Some of them displayed potent anti-proliferative activity against human vascular endothelial cell (EA.hy926). In particular, two potent compounds (CDAU-1 and CDAU-2) could be considered as promising anti-angiogenesis agents with triplet inhibition profile. The biological evaluation and molecular docking results indicate that N-pyridin-2-ylcyclopropane carboxamide could serve as a hinge-binding group (HBG) for the discovery of multi-target anti-angiogenesis agents. CDAU-2 also exhibited promising anti-angiogenic potency in a tissue model for angiogenesis. PMID:28332573

The Curcumin Analog C-150, Influencing NF-κB, UPR and Akt/Notch Pathways Has Potent Anticancer Activity In Vitro and In Vivo.

PubMed

Hackler, László; Ózsvári, Béla; Gyuris, Márió; Sipos, Péter; Fábián, Gabriella; Molnár, Eszter; Marton, Annamária; Faragó, Nóra; Mihály, József; Nagy, Lajos István; Szénási, Tibor; Diron, Andrea; Párducz, Árpád; Kanizsai, Iván; Puskás, László G

2016-01-01

C-150 a Mannich-type curcumin derivative, exhibited pronounced cytotoxic effects against eight glioma cell lines at micromolar concentrations. Inhibition of cell proliferation by C-150 was mediated by affecting multiple targets as confirmed at transcription and protein level. C-150 effectively reduced the transcription activation of NFkB, inhibited PKC-alpha which are constitutively over-expressed in glioblastoma. The effects of C-150 on the Akt/ Notch signaling were also demonstrated in a Drosophila tumorigenesis model. C-150 reduced the number of tumors in Drosophila with similar efficacy to mitoxantrone. In an in vivo orthotopic glioma model, C-150 significantly increased the median survival of treated nude rats compared to control animals. The multi-target action of C-150, and its preliminary in vivo efficacy would render this curcumin analogue as a potent clinical candidate against glioblastoma.

Antifungal activity of rimocidin and a new rimocidin derivative BU16 produced by Streptomyces mauvecolor BU16 and their effects on pepper anthracnose.

PubMed

Jeon, B J; Kim, J D; Han, J W; Kim, B S

2016-05-01

The objective of this study was to explore antifungal metabolites targeting fungal cell envelope and to evaluate the control efficacy against anthracnose development in pepper plants. A natural product library comprising 3000 microbial culture extracts was screened via an adenylate kinase (AK)-based cell lysis assay to detect antifungal metabolites targeting the cell envelope of plant-pathogenic fungi. The culture extract of Streptomyces mauvecolor strain BU16 displayed potent AK-releasing activity. Rimocidin and a new rimocidin derivative, BU16, were identified from the extract as active constituents. BU16 is a tetraene macrolide containing a six-membered hemiketal ring with an ethyl group side chain instead of the propyl group in rimocidin. Rimocidin and BU16 showed broad-spectrum antifungal activity against various plant-pathogenic fungi and demonstrated potent control efficacy against anthracnose development in pepper plants. Antifungal metabolites produced by S. mauvecolor strain BU16 were identified to be rimocidin and BU16. The compounds displayed potent control efficacy against pepper anthracnose. Rimocidin and BU16 would be active ingredients of disease control agents disrupting cell envelope of plant-pathogenic fungi. The structure and antifungal activity of rimocidin derivative BU16 is first described in this study. © 2016 The Society for Applied Microbiology.

Novel triterpenoids isolated from raisins exert potent antiproliferative activities by targeting mitochondrial and Ras/Raf/ERK signaling in human breast cancer cells.

PubMed

Liu, Juan; Wang, Yihai; Liu, Rui Hai; He, Xiangjiu

2016-07-13

Raisins are produced in many regions of the world and may be eaten raw or used in cooking, baking and brewing. Bioactivity-guided fractionation of raisins was used to determine the chemical identity of bioactive constituents. Seven triterpenoids, including three novel triterpenoids, were isolated and identified. The novel triterpenoids were elucidated to be 3β,13β-dihydroxy-12,13-dihydrooleanolic acid (1), 3β,12β,13β-trihydroxy-12,13-dihydrooleanolic acid (2, TOA), and 3β,13β-dihydroxy-12,13-dihydroursolic acid (7), respectively. TOA showed the highest antiproliferative activity against MCF-7/DOX cells, with an EC50 value of 3.60 ± 0.55 μM. Compounds 1, 3 and 7 also exhibited potent antiproliferative activity against MCF-7/DOX cells, with an EC50 value of 7.10 ± 0.65, 10.22 ± 0.90 and 8.91 ± 1.12 μM. Compounds 1 and 2 also exhibited potent antioxidant activities. Moreover, the detailed cytotoxic mechanisms of TOA were investigated by targeting the mitochondrial and protein tyrosine kinase signaling (Ras/Raf/ERK). The results strongly demonstrated that the novel triterpenoids isolated from raisins could be promising candidates for therapy of breast cancer.

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.

PubMed

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

2016-01-26

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.

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

PubMed Central

Musi, Elgilda; de Stanchina, Elisa; Schwartz, Gary K.

2016-01-01

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. PMID:26675259

Design and Discovery of N -(2-Methyl-5'-morpholino-6'-((tetrahydro-2 H -pyran-4-yl)oxy)-[3,3'-bipyridin]-5-yl)-3-(trifluoromethyl)benzamide (RAF709): A Potent, Selective, and Efficacious RAF Inhibitor Targeting RAS Mutant Cancers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nishiguchi, Gisele A.; Rico, Alice; Tanner, Huw

RAS oncogenes have been implicated in >30% of human cancers, all representing high unmet medical need. The exquisite dependency on CRAF kinase in KRAS mutant tumors has been established in genetically engineered mouse models and human tumor cells. To date, many small molecule approaches are under investigation to target CRAF, yet kinase-selective and cellular potent inhibitors remain challenging to identify. Herein, we describe 14 (RAF709) [Aversa, Biaryl amide compounds as kinase inhibitors and their preparation. WO 2014151616, 2014], a selective B/C RAF inhibitor, which was developed through a hypothesis-driven approach focusing on drug-like properties. A key challenge encountered in themore » medicinal chemistry campaign was maintaining a balance between good solubility and potent cellular activity (suppression of pMEK and proliferation) in KRAS mutant tumor cell lines. We investigated the small molecule crystal structure of lead molecule 7 and hypothesized that disruption of the crystal packing would improve solubility, which led to a change from N-methylpyridone to a tetrahydropyranyl oxy-pyridine derivative. 14 proved to be soluble, kinase selective, and efficacious in a KRAS mutant xenograft model.« less

Discovery of a tetrahydropyrimidin-2(1H)-one derivative (TAK-442) as a potent, selective, and orally active factor Xa inhibitor.

PubMed

Fujimoto, Takuya; Imaeda, Yasuhiro; Konishi, Noriko; Hiroe, Katsuhiko; Kawamura, Masaki; Textor, Garret P; Aertgeerts, Kathleen; Kubo, Keiji

2010-05-13

Coagulation enzyme factor Xa (FXa) is a particularly promising target for the development of new anticoagulant agents. We previously reported the imidazo[1,5-c]imidazol-3-one derivative 1 as a potent and orally active FXa inhibitor. However, it was found that 1 predominantly undergoes hydrolysis upon incubation with human liver microsomes, and the human specific metabolic pathway made it difficult to predict the human pharmacokinetics. To address this issue, our synthetic efforts were focused on modification of the imidazo[1,5-c]imidazol-3-one moiety of the active metabolite 3a, derived from 1, which resulted in the discovery of the tetrahydropyrimidin-2(1H)-one derivative 5k as a highly potent and selective FXa inhibitor. Compound 5k showed no detectable amide bond cleavage in human liver microsomes, exhibited a good pharmacokinetic profile in monkeys, and had a potent antithrombotic efficacy in a rabbit model without prolongation of bleeding time. Compound 5k is currently under clinical development with the code name TAK-442.

Cadmium is a potent inhibitor of PPM phosphatases and targets the M1 binding site

PubMed Central

Pan, Chang; Liu, Hong-Da; Gong, Zheng; Yu, Xiao; Hou, Xu-Ben; Xie, Di-Dong; Zhu, Xi-Bin; Li, Hao-Wen; Tang, Jun-Yi; Xu, Yun-Fei; Yu, Jia-Qi; Zhang, Lian-Ying; Fang, Hao; Xiao, Kun-Hong; Chen, Yu-Guo; Wang, Jiang-Yun; Pang, Qi; Chen, Wei; Sun, Jin-Peng

2013-01-01

The heavy metal cadmium is a non-degradable pollutant. By screening the effects of a panel of metal ions on the phosphatase activity, we unexpectedly identified cadmium as a potent inhibitor of PPM1A and PPM1G. In contrast, low micromolar concentrations of cadmium did not inhibit PP1 or tyrosine phosphatases. Kinetic studies revealed that cadmium inhibits PPM phosphatases through the M1 metal ion binding site. In particular, the negative charged D441 in PPM1G specific recognized cadmium. Our results suggest that cadmium is likely a potent inhibitor of most PPM family members except for PHLPPs. Furthermore, we demonstrated that cadmium inhibits PPM1A-regulated MAPK signaling and PPM1G-regulated AKT signaling potently in vivo. Cadmium reversed PPM1A-induced cell cycle arrest and cadmium insensitive PPM1A mutant rescued cadmium induced cell death. Taken together, these findings provide a better understanding of the effects of the toxicity of cadmium in the contexts of human physiology and pathology. PMID:23903585

Rapid profiling of RSV antibody repertoires from the memory B cells of naturally infected adult donors.

PubMed

Gilman, Morgan S A; Castellanos, Carlos A; Chen, Man; Ngwuta, Joan O; Goodwin, Eileen; Moin, Syed M; Mas, Vicente; Melero, José A; Wright, Peter F; Graham, Barney S; McLellan, Jason S; Walker, Laura M

2016-12-16

Respiratory syncytial virus (RSV) causes substantial morbidity and mortality in young children and the elderly. There are currently no licensed RSV vaccines, and passive prophylaxis with the monoclonal antibody palivizumab is restricted to high-risk infants in part due to its modest efficacy. Although it is widely agreed that an effective RSV vaccine will require the induction of a potent neutralizing antibody response against the RSV fusion (F) glycoprotein, little is known about the specificities and functional activities of RSV F-specific antibodies induced by natural infection. Here, we have comprehensively profiled the human antibody response to RSV F by isolating and characterizing 364 RSV F-specific monoclonal antibodies from the memory B cells of three healthy adult donors. In all donors, the antibody response to RSV F is comprised of a broad diversity of clones that target several antigenic sites. Nearly half of the most potent antibodies target a previously undefined site of vulnerability near the apex of the prefusion conformation of RSV F (preF), providing strong support for the development of RSV vaccine candidates that preserve the membrane-distal hemisphere of the preF protein. Additionally, the antibodies targeting this new site display convergent sequence features, thus providing a future means to rapidly detect the presence of these antibodies in human vaccine samples. Many of the antibodies that bind preF-specific surfaces are over 100 times more potent than palivizumab, and several cross-neutralize human metapneumovirus (HMPV). Taken together, the results have implications for the design and evaluation of RSV vaccine candidates and offer new options for passive prophylaxis.

Study of magnetization switching for MRAM based memory technologies

NASA Astrophysics Data System (ADS)

Pham, Huy

Amphibian alkaloids are attractive targets for synthesis due to their biological activity. An important class of amphibian alkaloids is the 2,5-disubstituted pyrrolidine-based family of compounds. There are many synthetic approaches for the preparation of the trans-2,5-disubstituted pyrrolidines, but methods for the construction of the cis-2,5-pyrrolidines are limited. Therefore, it was desired to develop an enantioselective approach for the preparation of cis-2,5-disubsituted pyrrolidines. (+)-Tropin-2-one derived from cocaine was used as starting material to exploit the inherent stereochemistry for construction of the cis-pyrrolidine ring. This permitted the unequivocal assignment of the absolute configuration of the target pyrrolidine. The structurally simple pyrrolidine alkaloid, 225H, was selected as a target to develop a general synthetic approach. The enantioselective synthesis of 225H was achieved in nine steps and good overall yield. The search for potent cannabinoid receptor partial agonist ligands as potential marijuana addiction therapeutic agents has led to an investigation of the synthesis of diaryl ether hybrid analogues of BAY 59-3074. A series of 2-(3-alkyl-5-hydroxyphenoxy)-6-(trifluoromethyl)benzonitriles, 3-(2-cyano-3-(trifluoromethyl)phenoxy)phenylalkanoates, and (3-(benzyloxy)phenoxy)-6-(trifluoromethyl)benzonitriles were synthesized and evaluated in vitro for CB1 affinity. The olivetol diaryl ether analogue was the most potent ligand of the alkyl series, but the diaryl ester analogues exhibited modest affinity for CB1 receptors. The most potent compound of the series was the 2-(3-(benzyloxy)phenoxy)-6-(trifluoromethyl)benzonitrile. Keywords. amphibian alkaloids, enantioselective synthesis, pyrrolidine, cannabinoid receptor, marijuana.

Multiparametric Phenotypic Screening System for Profiling Bioactive Compounds Using Human Fetal Hippocampal Neural Stem/Progenitor Cells.

PubMed

Tabata, Yoshikuni; Murai, Norio; Sasaki, Takeo; Taniguchi, Sachie; Suzuki, Shuichi; Yamazaki, Kazuto; Ito, Masashi

2015-10-01

Stem cell research has been progressing rapidly, contributing to regenerative biology and regenerative medicine. In this field, small-molecule compounds affecting stem cell proliferation/differentiation have been explored to understand stem cell biology and support regenerative medicine. In this study, we established a multiparametric screening system to detect bioactive compounds affecting the cell fate of human neural stem/progenitor cells (NSCs/NPCs), using human fetal hippocampal NSCs/NPCs, HIP-009 cells. We examined effects of 410 compounds, which were collected based on mechanisms of action (MOAs) and chemotypes, on HIP-009's cell fate (self-renewal, neuronal and astrocytic differentiation) and morphology by automated multiparametric assays and profiled induced cellular phenotypes. We found that this screening classified compounds with the same MOAs into subgroups according to additional pharmacological effects (e.g., mammalian target of rapamycin complex 1 [mTORC1] inhibitors and mTORC1/mTORC2 dual inhibitors among mTOR inhibitors). Moreover, it identified compounds that have off-target effects under matrix analyses of MOAs and structure similarities (e.g., neurotropic effects of amitriptyline among tri- and tetracyclic compounds). Therefore, this automated, medium-throughput and multiparametric screening system is useful for finding compounds that affect the cell fate of human NSCs/NPCs for supporting regenerative medicine and to fingerprint compounds based on human stem cells' multipotency, leading to understanding of stem cell biology. © 2015 Society for Laboratory Automation and Screening.

Novel methyl indolinone-6-carboxylates containing an indole moiety as angiokinase inhibitors.

PubMed

Qin, Mingze; Tian, Ye; Sun, Xiaoqing; Yu, Simiao; Xia, Juanjuan; Gong, Ping; Zhang, Haotian; Zhao, Yanfang

2017-10-20

A novel series of methyl indolinone-6-carboxylates bearing an indole moiety were identified as potent angiokinase inhibitors. The most active compound, A8, potently targeted the kinase activities of vascular endothelial growth factor receptors 2 and 3, and platelet-derived growth factor receptors α and β, with IC 50 values in the nanomolar range. In addition, A8 effectively suppressed the proliferation of human umbilical vein endothelial cells, and HT-29 and MCF-7 cancer cells, by inducing apoptosis. Compound A8 is thus a promising candidate for further investigation. Copyright © 2017. Published by Elsevier Masson SAS.

Pin1 inhibition exerts potent activity against acute myeloid leukemia through blocking multiple cancer-driving pathways.

PubMed

Lian, Xiaolan; Lin, Yu-Min; Kozono, Shingo; Herbert, Megan K; Li, Xin; Yuan, Xiaohong; Guo, Jiangrui; Guo, Yafei; Tang, Min; Lin, Jia; Huang, Yiping; Wang, Bixin; Qiu, Chenxi; Tsai, Cheng-Yu; Xie, Jane; Cao, Ziang Jeff; Wu, Yong; Liu, Hekun; Zhou, Xiaozhen; Lu, Kunping; Chen, Yuanzhong

2018-05-30

The increasing genomic complexity of acute myeloid leukemia (AML), the most common form of acute leukemia, poses a major challenge to its therapy. To identify potent therapeutic targets with the ability to block multiple cancer-driving pathways is thus imperative. The unique peptidyl-prolyl cis-trans isomerase Pin1 has been reported to promote tumorigenesis through upregulation of numerous cancer-driving pathways. Although Pin1 is a key drug target for treating acute promyelocytic leukemia (APL) caused by a fusion oncogene, much less is known about the role of Pin1 in other heterogeneous leukemia. The mRNA and protein levels of Pin1 were detected in samples from de novo leukemia patients and healthy controls using real-time quantitative RT-PCR (qRT-PCR) and western blot. The establishment of the lentiviral stable-expressed short hairpin RNA (shRNA) system and the tetracycline-inducible shRNA system for targeting Pin1 were used to analyze the biological function of Pin1 in AML cells. The expression of cancer-related Pin1 downstream oncoproteins in shPin1 (Pin1 knockdown) and Pin1 inhibitor all-trans retinoic acid (ATRA) treated leukemia cells were examined by western blot, followed by evaluating the effects of genetic and chemical inhibition of Pin1 in leukemia cells on transformed phenotype, including cell proliferation and colony formation ability, using trypan blue, cell counting assay, and colony formation assay in vitro, as well as the tumorigenesis ability using in vivo xenograft mouse models. First, we found that the expression of Pin1 mRNA and protein was significantly increased in both de novo leukemia clinical samples and multiple leukemia cell lines, compared with healthy controls. Furthermore, genetic or chemical inhibition of Pin1 in human multiple leukemia cell lines potently inhibited multiple Pin1 substrate oncoproteins and effectively suppressed leukemia cell proliferation and colony formation ability in cell culture models in vitro. Moreover, tetracycline-inducible Pin1 knockdown and slow-releasing ATRA potently inhibited tumorigenicity of U937 and HL-60 leukemia cells in xenograft mouse models. We demonstrate that Pin1 is highly overexpressed in human AML and is a promising therapeutic target to block multiple cancer-driving pathways in AML.

Consensus Induced Fit Docking (cIFD): methodology, validation, and application to the discovery of novel Crm1 inhibitors

NASA Astrophysics Data System (ADS)

Kalid, Ori; Toledo Warshaviak, Dora; Shechter, Sharon; Sherman, Woody; Shacham, Sharon

2012-11-01

We present the Consensus Induced Fit Docking (cIFD) approach for adapting a protein binding site to accommodate multiple diverse ligands for virtual screening. This novel approach results in a single binding site structure that can bind diverse chemotypes and is thus highly useful for efficient structure-based virtual screening. We first describe the cIFD method and its validation on three targets that were previously shown to be challenging for docking programs (COX-2, estrogen receptor, and HIV reverse transcriptase). We then demonstrate the application of cIFD to the challenging discovery of irreversible Crm1 inhibitors. We report the identification of 33 novel Crm1 inhibitors, which resulted from the testing of 402 purchased compounds selected from a screening set containing 261,680 compounds. This corresponds to a hit rate of 8.2 %. The novel Crm1 inhibitors reveal diverse chemical structures, validating the utility of the cIFD method in a real-world drug discovery project. This approach offers a pragmatic way to implicitly account for protein flexibility without the additional computational costs of ensemble docking or including full protein flexibility during virtual screening.

Inhibitory Effect of 2,3,5,6-Tetrafluoro-4-[4-(aryl)-1H-1,2,3-triazol-1-yl]benzenesulfonamide Derivatives on HIV Reverse Transcriptase Associated RNase H Activities

PubMed Central

Pala, Nicolino; Esposito, Francesca; Rogolino, Dominga; Carcelli, Mauro; Sanna, Vanna; Palomba, Michele; Naesens, Lieve; Corona, Angela; Grandi, Nicole; Tramontano, Enzo; Sechi, Mario

2016-01-01

The HIV-1 ribonuclease H (RNase H) function of the reverse transcriptase (RT) enzyme catalyzes the selective hydrolysis of the RNA strand of the RNA:DNA heteroduplex replication intermediate, and represents a suitable target for drug development. A particularly attractive approach is constituted by the interference with the RNase H metal-dependent catalytic activity, which resides in the active site located at the C-terminus p66 subunit of RT. Herein, we report results of an in-house screening campaign that allowed us to identify 4-[4-(aryl)-1H-1,2,3-triazol-1-yl]benzenesulfonamides, prepared by the “click chemistry” approach, as novel potential HIV-1 RNase H inhibitors. Three compounds (9d, 10c, and 10d) demonstrated a selective inhibitory activity against the HIV-1 RNase H enzyme at micromolar concentrations. Drug-likeness, predicted by the calculation of a panel of physicochemical and ADME properties, putative binding modes for the active compounds, assessed by computational molecular docking, as well as a mechanistic hypothesis for this novel chemotype are reported. PMID:27556447

Combination of Pharmacophore Matching, 2D Similarity Search, and In Vitro Biological Assays in the Selection of Potential 5-HT6 Antagonists from Large Commercial Repositories.

PubMed

Dobi, Krisztina; Flachner, Beáta; Pukáncsik, Mária; Máthé, Enikő; Bognár, Melinda; Szaszkó, Mária; Magyar, Csaba; Hajdú, István; Lőrincz, Zsolt; Simon, István; Fülöp, Ferenc; Cseh, Sándor; Dormán, György

2015-10-01

Rapid in silico selection of target-focused libraries from commercial repositories is an attractive and cost-effective approach. If structures of active compounds are available, rapid 2D similarity search can be performed on multimillion compound databases, but the generated library requires further focusing. We report here a combination of the 2D approach with pharmacophore matching which was used for selecting 5-HT6 antagonists. In the first screening round, 12 compounds showed >85% antagonist efficacy of the 91 screened. For the second-round (hit validation) screening phase, pharmacophore models were built, applied, and compared with the routine 2D similarity search. Three pharmacophore models were created based on the structure of the reference compounds and the first-round hit compounds. The pharmacophore search resulted in a high hit rate (40%) and led to novel chemotypes, while 2D similarity search had slightly better hit rate (51%), but lacking the novelty. To demonstrate the power of the virtual screening cascade, ligand efficiency indices were also calculated and their steady improvement was confirmed. © 2015 John Wiley & Sons A/S.

Finding Inspiration in the Protein Data Bank to Chemically Antagonize Readers of the Histone Code.

PubMed

Campagna-Slater, Valérie; Schapira, Matthieu

2010-04-12

Members of the Royal family of proteins are readers of the histone code that contain aromatic cages capable of recognizing specific sequences and lysine methylation states on histone tails. These binding modules play a key role in epigenetic signalling, and are part of a larger group of epigenetic targets that are becoming increasingly attractive for drug discovery. In the current study, pharmacophore representations of the aromatic cages forming the methyl-lysine (Me-Lys) recognition site were used to search the Protein Data Bank (PDB) for ligand binding pockets possessing similar chemical and geometrical features in unrelated proteins. The small molecules bound to these sites were then extracted from the PDB, and clustered based on fragments binding to the aromatic cages. The compounds collected are numerous and structurally diverse, but point to a limited set of preferred chemotypes; these include quaternary ammonium, sulfonium, and primary, secondary and tertiary amine moieties, as well as aromatic, aliphatic or orthogonal rings, and bicyclic systems. The chemical tool-kit identified can be used to design antagonists of the Royal family and related proteins. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synergistic Effect of MiR-146a Mimic and Cetuximab on Hepatocellular Carcinoma Cells

PubMed Central

Huang, Suning; Rong, Minhua; Dang, Yiwu

2014-01-01

Previously, we found that the expression of microRNA-146a (miR-146a) was downregulated in hepatocellular carcinoma (HCC) formalin-fixed paraffin-embedded (FFPE) tissues compared to the adjacent noncancerous hepatic tissues. In the current study, we have explored the in vitro effect of miR-146a on the malignant phenotypes of HCC cells. MiR-146a mimic could suppress cell growth and increase cellular apoptosis in HCC cell lines HepG2, HepB3, and SNU449, as assessed by spectrophotometry, fluorimetry, and fluorescence microscopy, respectively. Furthermore, western blot showed that miR-146a mimic downregulated EGFR, ERK1/2, and stat5 signalings. These effects were less potent compared to that of a siRNA targeting EGFR, a known target gene of miR-146a. Moreover, miR-146a mimic could enhance the cell growth inhibition and apoptosis induction impact of various EGFR targeting agents. The most potent combination was miR-146a mimic with cetuximab, presenting a synergistic effect. In conclusion, miR-146a plays a vital role in the cell growth and apoptosis of HCC cells and inducing miR-146a level might be a critical targeted molecular therapy strategy for HCC. PMID:24895573

Synergistic effect of MiR-146a mimic and cetuximab on hepatocellular carcinoma cells.

PubMed

Huang, Suning; He, Rongquan; Rong, Minhua; Dang, Yiwu; Chen, Gang

2014-01-01

Previously, we found that the expression of microRNA-146a (miR-146a) was downregulated in hepatocellular carcinoma (HCC) formalin-fixed paraffin-embedded (FFPE) tissues compared to the adjacent noncancerous hepatic tissues. In the current study, we have explored the in vitro effect of miR-146a on the malignant phenotypes of HCC cells. MiR-146a mimic could suppress cell growth and increase cellular apoptosis in HCC cell lines HepG2, HepB3, and SNU449, as assessed by spectrophotometry, fluorimetry, and fluorescence microscopy, respectively. Furthermore, western blot showed that miR-146a mimic downregulated EGFR, ERK1/2, and stat5 signalings. These effects were less potent compared to that of a siRNA targeting EGFR, a known target gene of miR-146a. Moreover, miR-146a mimic could enhance the cell growth inhibition and apoptosis induction impact of various EGFR targeting agents. The most potent combination was miR-146a mimic with cetuximab, presenting a synergistic effect. In conclusion, miR-146a plays a vital role in the cell growth and apoptosis of HCC cells and inducing miR-146a level might be a critical targeted molecular therapy strategy for HCC.

Galactose Derivative-Modified Nanoparticles for Efficient siRNA Delivery to Hepatocellular Carcinoma.

PubMed

Huang, Kuan-Wei; Lai, Yu-Tsung; Chern, Guann-Jen; Huang, Shao-Feng; Tsai, Chia-Lung; Sung, Yun-Chieh; Chiang, Cheng-Chin; Hwang, Pi-Bei; Ho, Ting-Lun; Huang, Rui-Lin; Shiue, Ting-Yun; Chen, Yunching; Wang, Sheng-Kai

2018-05-29

Successful siRNA therapy requires suitable delivery systems with targeting moieties such as small molecules, peptides, antibodies, or aptamers. Galactose (Gal) residues recognized by the asialoglycoprotein receptor (ASGPR) can serve as potent targeting moieties for hepatocellular carcinoma (HCC) cells. However, efficient targeting to HCC via galactose moieties rather than normal liver tissues in HCC patients remains a challenge. To achieve more efficient siRNA delivery in HCC, we synthesized various galactoside derivatives and investigated the siRNA delivery capability of nanoparticles modified with those galactoside derivatives. In this study, we assembled lipid/calcium/phosphate nanoparticles (LCP NPs) conjugated with eight types of galactoside derivatives and demonstrated that phenyl β-d-galactoside-decorated LCP NPs (L4-LCP NPs) exhibited a superior siRNA delivery into HCC cells compared to normal hepatocytes. VEGF siRNAs delivered by L4-LCP NPs downregulated VEGF expression in HCC in vitro and in vivo and led to a potent antiangiogenic effect in the tumor microenvironment of a murine orthotopic HCC model. The efficient delivery of VEGF siRNA by L4-LCP NPs that resulted in significant tumor regression indicates that phenyl galactoside could be a promising HCC-targeting ligand for therapeutic siRNA delivery to treat liver cancer.

EF24 induces ROS-mediated apoptosis via targeting thioredoxin reductase 1 in gastric cancer cells

PubMed Central

Chen, Weiqian; Chen, Xi; Ying, Shilong; Feng, Zhiguo; Chen, Tongke; Ye, Qingqing; Wang, Zhe; Qiu, Chenyu; Yang, Shulin; Liang, Guang

2016-01-01

Gastric cancer (GC) is one of the leading causes of cancer mortality in the world, and finding novel agents for the treatment of advanced gastric cancer is of urgent need. Diphenyl difluoroketone (EF24), a molecule having structural similarity to curcumin, exhibits potent anti-tumor activities by arresting cell cycle and inducing apoptosis. Although EF24 demonstrates potent anticancer efficacy in numerous types of human cancer cells, the cellular targets of EF24 have not been fully defined. We report here that EF24 may interact with the thioredoxin reductase 1 (TrxR1), an important selenocysteine (Sec)-containing antioxidant enzyme, to induce reactive oxygen species (ROS)-mediated apoptosis in human gastric cancer cells. By inhibiting TrxR1 activity and increasing intracellular ROS levels, EF24 induces a lethal endoplasmic reticulum stress in human gastric cancer cells. Importantly, knockdown of TrxR1 sensitizes cells to EF24 treatment. In vivo, EF24 treatment markedly reduces the TrxR1 activity and tumor cell burden, and displays synergistic lethality with 5-FU against gastric cancer cells. Targeting TrxR1 with EF24 thus discloses a previously unrecognized mechanism underlying the biological activity of EF24, and reveals that TrxR1 is a good target for gastric cancer therapy. PMID:26919110

Specificity in the interaction of natural products with their target proteins--a biochemical and structural insight.

PubMed

Venkatraman, Prasanna

2010-06-01

Natural products are an abundant source of anti cancer agents. They act as cytotoxic drugs, and inhibitors of apoptosis, transcription, cell proliferation and angiogenesis. While pathways targeted by natural products have been well studied, there is paucity of information about the in vivo molecular target/s of these compounds. This review summarizes some of the natural compounds for which the molecular targets, mechanism of action and structural basis of specificity have been well documented. These examples illustrate that 'off target' binding can be explained on the basis of diversity inherent to biomolecular interactions. There is enough evidence to suggest that natural compounds are potent and versatile warheads that can be optimized for a multi targeted therapeutic intervention in cancer.

Temporal dynamics and population genetic structure of Fusarium graminearum in the upper Midwestern United States.

PubMed

Liang, J M; Xayamongkhon, H; Broz, K; Dong, Y; McCormick, S P; Abramova, S; Ward, T J; Ma, Z H; Kistler, H C

2014-12-01

Fusarium graminearum sensu stricto causes Fusarium head blight (FHB) in wheat and barley, and contaminates grains with several trichothecene mycotoxins, causing destructive yield losses and economic impact in the United States. Recently, a F. graminearum strain collected from Minnesota (MN) was determined to produce a novel trichothecene toxin, called NX-2. In order to determine the spatial and temporal dynamics of NX-2 producing strains in MN, North Dakota (ND) and South Dakota (SD), a total of 463 F. graminearum strains were collected from three sampling periods, 1999-2000, 2006-2007 and 2011-2013. A PCR-RFLP based diagnostic test was developed and validated for NX-2 producing strains based on polymorphisms in the Tri1 gene. Trichothecene biosynthesis gene (Tri gene)-based polymerase chain reaction (PCR) assays and ten PCR-restriction fragment length polymorphism (RFLP) markers were used to genotype all strains. NX-2 strains were detected in each sampling period but with a very low overall frequency (2.8%) and were mainly collected near the borders of MN, ND and SD. Strains with the 3ADON chemotype were relatively infrequent in 1999-2000 (4.5%) but increased to 29.4% in 2006-2007 and 17.2% in 2011-2013. The distribution of 3ADON producing strains also expanded from a few border counties between ND and MN in 1999-2000, southward toward the border between SD and MN in 2006-2007 and westward in 2011-2013. Genetic differentiation between 2006-2007 and 2011-2013 populations (3%) was much lower than that between 1999-2000 and 2006-2007 (22%) or 1999-2000 and 2011-2013 (20%) suggesting that most change to population genetic structure of F. graminearum occurred between 1999-2000 and 2006-2007. This change was associated with the emergence of a new population consisting largely of individuals with a 3ADON chemotype. A Bayesian clustering analysis suggested that NX-2 chemotype strains are part of a previously described Upper Midwestern population. However, these analyses also suggest that the NX-2 isolates could represent a distinct population, but that interpretations of population assignment are influenced by the small number of NX-2 strains available for analysis. Published by Elsevier Inc.

Discovery of novel selenium derivatives as Pin1 inhibitors by high-throughput screening

DOE Office of Scientific and Technical Information (OSTI.GOV)

Subedi, Amit; Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570; Shimizu, Takeshi

2016-06-03

Peptidyl prolyl cis/trans isomerization by Pin1 regulates various oncogenic signals during cancer progression, and its inhibition through multiple approaches has established Pin1 as a therapeutic target. However, lack of simplified screening systems has limited the discovery of potent Pin1 inhibitors. We utilized phosphorylation-dependent binding of Pin1 to its specific substrate to develop a screening system for Pin1 inhibitors. Using this system, we screened a chemical library, and identified a novel selenium derivative as Pin1 inhibitor. Based on structure-activity guided chemical synthesis, we developed more potent Pin1 inhibitors that inhibited cancer cell proliferation. -- Highlights: •Novel screening for Pin1 inhibitors basedmore » on Pin1 binding is developed. •A novel selenium compound is discovered as Pin1 inhibitor. •Activity guided chemical synthesis of selenium derivatives resulted potent Pin1 inhibitors.« less

Synthesis and biological evaluation of novel alkyl diamine linked bivalent β-carbolines as angiogenesis inhibitors.

PubMed

Chen, Wei; Zhang, Guoxian; Guo, Liang; Fan, Wenxi; Ma, Qin; Zhang, Xiaodong; Du, Runlei; Cao, Rihui

2016-11-29

We have synthesized and evaluated a series of novel alkyl diamine linked bivalent β-carbolines as potent angiogenesis inhibitors. The results demonstrated that most bivalent β-carbolines exhibited significant antiproliferative effects against human umbilical vein cell lines EA.HY926. Compound 4m was found to be the most potent antiproliferative agent with IC 50 value of 2.16 μM against EA.HY926 cell lines. Mechanism investigations revealed that compound 4m could significantly inhibit EA.HY926 cells migration and tube formation in a dose-dependent manner. Moreover, compound 4m also showed obvious angiogenesis inhibitory effects in CAM assay, and the antiangiogenetic potency was more potent than the reference drug Endostar. The bivalent β-carbolines might be served as candidates for the development of vascular targeting antitumor drugs. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Discovery of novel high potent and cellular active ADC type PTP1B inhibitors with selectivity over TC-PTP via modification interacting with C site.

PubMed

Du, Yongli; Zhang, Yanhui; Ling, Hao; Li, Qunyi; Shen, Jingkang

2018-01-20

PTP1B serving as a key negative regulator of insulin signaling is a novel target for type 2 diabetes and obesity. Modification at ring B of N-{4-[(3-Phenyl-ureido)-methyl]-phenyl}-methane-sulfonamide template to interact with residues Arg47 and Lys41 in the C site of PTP1B by molecular docking aided design resulted in the discovery of a series of novel high potent and selective inhibitors of PTP1B. The structure activity relationship interacting with the C site of PTP1B was well illustrated. Compounds 8 and 18 were shown to be the high potent and most promising PTP1B inhibitors with cellular activity and great selectivity over the highly homologous TCPTP and other PTPs. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Optimization of 2-Anilino 4-Amino Substituted Quinazolines into Potent Antimalarial Agents with Oral in Vivo Activity.

PubMed

Gilson, Paul R; Tan, Cyrus; Jarman, Kate E; Lowes, Kym N; Curtis, Joan M; Nguyen, William; Di Rago, Adrian E; Bullen, Hayley E; Prinz, Boris; Duffy, Sandra; Baell, Jonathan B; Hutton, Craig A; Jousset Subroux, Helene; Crabb, Brendan S; Avery, Vicky M; Cowman, Alan F; Sleebs, Brad E

2017-02-09

Novel antimalarial therapeutics that target multiple stages of the parasite lifecycle are urgently required to tackle the emerging problem of resistance with current drugs. Here, we describe the optimization of the 2-anilino quinazoline class as antimalarial agents. The class, identified from publicly available antimalarial screening data, was optimized to generate lead compounds that possess potent antimalarial activity against P. falciparum parasites comparable to the known antimalarials, chloroquine and mefloquine. During the optimization process, we defined the functionality necessary for activity and improved in vitro metabolism and solubility. The resultant lead compounds possess potent activity against a multidrug resistant strain of P. falciparum and arrest parasites at the ring phase of the asexual stage and also gametocytogensis. Finally, we show that the lead compounds are orally efficacious in a 4 day murine model of malaria disease burden.

Recent progress of the development of dipeptidyl peptidase-4 inhibitors for the treatment of type 2 diabetes mellitus.

PubMed

Li, Ning; Wang, Li-Jun; Jiang, Bo; Li, Xiang-Qian; Guo, Chuan-Long; Guo, Shu-Ju; Shi, Da-Yong

2018-05-10

Diabetes is a fast growing chronic metabolic disorder around the world. Dipeptidyl peptidase-4 (DPP-4) is a new promising target during type 2 diabetes glycemic control. Thus, a number of potent DPP-4 inhibitors were developed and play a rapidly evolving role in the management of type 2 diabetes in recent years. This article reviews the development of synthetic and natural DPP-4 inhibitors from 2012 to 2017 and provides their physico-chemical properties, biological activities against DPP-4 and selectivity over dipeptidyl peptidase-8/9. Moreover, the glucose-lowering mechanisms and the active site of DPP-4 are also discussed. We also discuss strategies and structure-activity relationships for identifying potent DPP-4 inhibitors, which will provide useful information for developing potent DPP-4 drugs as type 2 diabtes treatments. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Inhibitors of plasmodial serine hydroxymethyltransferase (SHMT): cocrystal structures of pyrazolopyrans with potent blood- and liver-stage activities.

PubMed

Witschel, Matthias C; Rottmann, Matthias; Schwab, Anatol; Leartsakulpanich, Ubolsree; Chitnumsub, Penchit; Seet, Michael; Tonazzi, Sandro; Schwertz, Geoffrey; Stelzer, Frank; Mietzner, Thomas; McNamara, Case; Thater, Frank; Freymond, Céline; Jaruwat, Aritsara; Pinthong, Chatchadaporn; Riangrungroj, Pinpunya; Oufir, Mouhssin; Hamburger, Matthias; Mäser, Pascal; Sanz-Alonso, Laura M; Charman, Susan; Wittlin, Sergio; Yuthavong, Yongyuth; Chaiyen, Pimchai; Diederich, François

2015-04-09

Several of the enzymes related to the folate cycle are well-known for their role as clinically validated antimalarial targets. Nevertheless for serine hydroxymethyltransferase (SHMT), one of the key enzymes of this cycle, efficient inhibitors have not been described so far. On the basis of plant SHMT inhibitors from an herbicide optimization program, highly potent inhibitors of Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) SHMT with a pyrazolopyran core structure were identified. Cocrystal structures of potent inhibitors with PvSHMT were solved at 2.6 Å resolution. These ligands showed activity (IC50/EC50 values) in the nanomolar range against purified PfSHMT, blood-stage Pf, and liver-stage P. berghei (Pb) cells and a high selectivity when assayed against mammalian cell lines. Pharmacokinetic limitations are the most plausible explanation for lack of significant activity of the inhibitors in the in vivo Pb mouse malaria model.

Discovery of potent NEK2 inhibitors as potential anticancer agents using structure-based exploration of NEK2 pharmacophoric space coupled with QSAR analyses.

PubMed

Khanfar, Mohammad A; Banat, Fahmy; Alabed, Shada; Alqtaishat, Saja

2017-02-01

High expression of Nek2 has been detected in several types of cancer and it represents a novel target for human cancer. In the current study, structure-based pharmacophore modeling combined with multiple linear regression (MLR)-based QSAR analyses was applied to disclose the structural requirements for NEK2 inhibition. Generated pharmacophoric models were initially validated with receiver operating characteristic (ROC) curve, and optimum models were subsequently implemented in QSAR modeling with other physiochemical descriptors. QSAR-selected models were implied as 3D search filters to mine the National Cancer Institute (NCI) database for novel NEK2 inhibitors, whereas the associated QSAR model prioritized the bioactivities of captured hits for in vitro evaluation. Experimental validation identified several potent NEK2 inhibitors of novel structural scaffolds. The most potent captured hit exhibited an [Formula: see text] value of 237 nM.

Substrate-based inhibitors exhibiting excellent protective and therapeutic effects against Botulinum Neurotoxin A intoxication.

PubMed

Guo, Jiubiao; Wang, Jinglin; Gao, Shan; Ji, Bin; Waichi Chan, Edward; Chen, Sheng

2015-11-20

Potent inhibitors to reverse Botulinum neurotoxins (BoNTs) activity in neuronal cells are currently not available. A better understanding of the substrate recognition mechanism of BoNTs enabled us to design a novel class of peptide inhibitors which were derivatives of the BoNT/A substrate, SNAP25. Through a combination of in vitro, cellular based, and in vivo mouse assays, several potent inhibitors of approximately one nanomolar inhibitory strength both in vitro and in vivo have been identified. These compounds represent the first set of inhibitors that exhibited full protection against BoNT/A intoxication in mice model with undetectable toxicity. Our findings validated the hypothesis that a peptide inhibitor targeting the two BoNT structural regions which were responsible for substrate recognition and cleavage respectively could exhibit excellent inhibitory effect, thereby providing insight on future development of more potent inhibitors against BoNTs.

Discovery of potent and selective rhodanine type IKKβ inhibitors by hit-to-lead strategy.

PubMed

Song, Hyeseung; Lee, Yun Suk; Roh, Eun Joo; Seo, Jae Hong; Oh, Kwang-Seok; Lee, Byung Ho; Han, Hogyu; Shin, Kye Jung

2012-09-01

Regulation of NF-κB activation through the inhibition of IKKβ has been identified as a promising target for the treatment of inflammatory and autoimmune disease such as rheumatoid arthritis. In order to develop novel IKKβ inhibitors, we performed high throughput screening toward around 8000 library compounds, and identified a hit compound containing rhodanine moiety. We modified the structure of hit compound to obtain potent and selective IKKβ inhibitors. Throughout hit-to-lead studies, we have discovered optimized compounds which possess blocking effect toward NF-κB activation and TNFα production in cell as well as inhibition activity against IKKβ. Among them, compound 3q showed the potent inhibitory activity against IKKβ, and excellent selectivity over other kinases such as p38α, p38β, JNK1, JNK2, and JNK3 as well as IKKα. Copyright © 2012 Elsevier Ltd. All rights reserved.

Novel Targeting Approach for Breast Cancer Gene Therapy

DTIC Science & Technology

2010-09-01

haloperidol and ibogaine)- conjugated polyamidoamine (PAMAM) dendrimers Poly(amidoamine) (PAMAM) dendrimers of 3.5 generation with carboxylate surface...Mukherjee A, Prasad TK, Rao NM, Banerjee R. Haloperidol associated stealth liposomes. A potent carrier for delivering genes to human breast cancer cells

Structural Biology and Molecular Modeling in the Design of Novel DPP-4 Inhibitors

NASA Astrophysics Data System (ADS)

Scapin, Giovanna

Inhibition of dipeptidyl peptidase IV (DPP-4) is a promising new approach for the treatment of type 2 diabetes. DPP-4 is the enzyme responsible for inactivating the incretin hormones glucagon-like peptide 1 (GLP-1) and glucose dependent insulinotropic polypeptide (GIP), two hormones that play important roles in glucose homeostasis. The potent, orally bioavailable and highly selective small molecule DPP-4 inhibitor sitagliptin has been approved by the FDA as novel drug for the treatment of type 2 diabetes. The comparison between the binding mode of sitagliptin (a β-amino acid) and that of a second class of inhibitors (α-amino acid-based) initially led to the successful identification and design of structurally diverse and highly potent DPP-4 inhibitors. Further analysis of the crystal structure of sitagliptin bound to DPP-4 suggested that the central β-amino butanoyl moiety could be replaced by a rigid group. This was confirmed by molecular modeling, and the resulting cyclohexylamine analogs were synthesized and found to be potent DPP-4 inhibitors. However, the triazolopyrazine was predicted to be distorted in order to fit in the binding pocket, and the crystal structure showed that multiple conformations exist for this moiety. Additional molecular modeling studies were then used to improve potency of the cyclohexylamine series. In addition, a 3-D QSAR method was used to gain insight for reducing off-target DPP-8/9 activities. Novel compounds were thus synthesized and found to be potent DPP-4 inhibitors. Two compounds in particular were designed to be highly selective against off-target "DPP-4 Activity- and/or Structure Homologues" (DASH) enzymes while maintaining potency against DPP-4.

Diverse heterocyclic scaffolds as dCTP pyrophosphatase 1 inhibitors. Part 1: Triazoles, triazolopyrimidines, triazinoindoles, quinoline hydrazones and arylpiperazines.

PubMed

Llona-Minguez, Sabin; Häggblad, Maria; Martens, Ulf; Throup, Adam; Loseva, Olga; Jemth, Ann-Sofie; Lundgren, Bo; Scobie, Martin; Helleday, Thomas

2017-08-15

A high-throughput screening campaign using a commercial compound library (ChemBridge DiverSET) revealed diverse chemotypes as inhibitors of the human dCTP pyrophosphatase 1 (dCTPase). Triazole, triazolopyrimidine, triazinoindole, quinoline hydrazone and arylpiperazine hits were clustered, confirmed by IC 50 determinations, and their preliminary structure-activity-relationships (SAR) and ligand efficiency scores are discussed in this letter. Copyright © 2017. Published by Elsevier Ltd.

Potential of targeting TGF-β for organ transplant patients

PubMed Central

Iwashima, Makio; Love, Robert

2015-01-01

TGF-β was originally considered as an immunoregulatory cytokine, but accumulating data demonstrate that it also plays a critical role in development of effector immunity. Since TGF-β has a potent ability to alter immune responses, modulation of the TGF-β pathway for treatment of transplantation patients could be effective if carried out in a target selective manner. This review will focus on the role of TGF-β in T cell differentiation and discuss the prospect of TGF-β as the therapeutic target of lung transplantation acceptance. PMID:23464518

Metabolomics assisted fingerprint of Hypericum perforatum chemotypes and assessment of their cytotoxic activity.

PubMed

Sarrou, Eirini; Giassafaki, Lefki-Pavlina; Masuero, Domenico; Perenzoni, Daniele; Vizirianakis, Ioannis S; Irakli, Maria; Chatzopoulou, Paschalina; Martens, Stefan

2018-04-01

Hypericum perforatum is known as an important medicinal plant, used for the treatment of several diseases, while its pharmacological properties are attributed to the presence of a wide range of secondary metabolites. Due to the great chemotypic variability of Hypericum species in the nature, and the demand for standardized herbal products, a detailed phytochemical investigation was carried out on different parts (herba, leaf, flowers) from wild collected and cultivated populations, using advanced chromatographic tools. Liquid Chromatographic analysis (LC-MS/MS MRM) revealed significant variability in the secondary metabolites content of the examined methanolic extracts. The most common derivatives belong to 9 groups i.e. benzoic acids, phenylpropanoids, coumarins, flavones, flavonols, flavan-3-ols, anthocyanins, phloroglucinols and naphtodianthrones. The main polyphenolic compounds were catechin, epicatechin, quercetin, quercetin 3-O-rhamnoside, quercetin 3-O-glucoside, neochlorogenic acid, proanthocyanidins (A and B series) and cyanidin-3-O-glucoside. In addition, the content of the characteristic compounds hypericin and hyperforin in herba crude extracts ranged between 0.5 and 1.7 mg/g and 0.6-3.3 mg/g respectively. The cytotoxic activity of the crude extracts was assessed at concentrations ranged between 0.01 and 100 μg/mL, on Caco-2 intestinal cancer cell cultures, and a cytotoxic behavior was shown only at the highest concentration of 100 μg/mL. Copyright © 2018 Elsevier Ltd. All rights reserved.

Pinus halepensis, Pinus pinaster, Pinus pinea and Pinus sylvestris Essential Oils Chemotypes and Monoterpene Hydrocarbon Enantiomers, before and after Inoculation with the Pinewood Nematode Bursaphelenchus xylophilus.

PubMed

Rodrigues, Ana M; Mendes, Marta D; Lima, Ana S; Barbosa, Pedro M; Ascensão, Lia; Barroso, José G; Pedro, Luis G; Mota, Manuel M; Figueiredo, A Cristina

2017-01-01

Pinewood nematode (PWN), Bursaphelenchus xylophilus, is the causal agent of pine wilt disease, a serious threat to global forest populations of conifers, especially Pinus spp. A time-course study of the essential oils (EOs) of 2-year-old Pinus halepensis, Pinus pinaster, Pinus pinea and Pinus sylvestris following inoculation with the PWN was performed. The constitutive and nematode inoculation induced EOs components were analyzed at both the wounding or inoculation areas and at the whole plant level. The enantiomeric ratio of optically active main EOs components was also evaluated. External symptoms of infection were observed only in P. pinaster and P. sylvestris 21 and 15 days after inoculation, respectively. The EO composition analysis of uninoculated and unwounded plants revealed the occurrence of chemotypes for P. pinaster, P. halepensis and P. sylvestris, whereas P. pinea showed a homogenous EO composition. When whole plants were evaluated for EO and monoterpene hydrocarbon enantiomeric chemical composition, no relevant qualitative and quantitative differences were found. Instead, EO analysis of inoculated and uninoculated wounded areas revealed an increase of sesquiterpenes and diterpenic compounds, especially in P. pinea and P. halepensis, comparatively to healthy whole plants EOs. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

Ethnopharmacological study of two Lippia species from Oriximiná, Brazil.

PubMed

Oliveira, Danilo R; Leitão, Gilda G; Santos, Stela S; Bizzo, Humberto R; Lopes, Daíse; Alviano, Celuta S; Alviano, Daniela S; Leitão, Suzana G

2006-11-03

Lippia alba (Miller) N.E. Brown is an aromatic herb that occurs in practically all regions of Brazil and has a large importance in Brazilian folk medicine. This species is characterized by a variability in morphology and in the chemical composition of the essential oil. The present work focused on the ethnopharmacological investigation of Lippia alba, locally known as "erva-cidreira" and Lippia alba f. intermedia, known as "carmelitana". In addition, the chemical composition and antimicrobial activity of their essential oils was investigated in order to correlate to their traditional uses. The ethnopharmacological study showed a good agreement of the major use (MUA) of Lippia alba (MUA=92.0%) and to a lesser extent, for Lippia alba f. intermedia (MUA=66.7%), as sedatives. The analyses of the essential oils allowed the identification of Lippia alba as a myrcene-citral chemotype (15% and 37.1%, respectively) and Lippia alba f. intermedia as a citral chemotype (22.1%). The essential oils of both species were active against all microorganisms assayed (bacteria and fungi) by the drop test, with inhibition halos ranging from 1.1 to 5.0 cm, probably due to the high content of oxygenated monoterpenes (51.0% and 40.1%, respectively), specially represented by aldehydes and alcohols. The chemical and pharmacological data of Lippia alba are in agreement with the ethnobotanical survey.

Comprehensive quality evaluation of medical Cannabis sativa L. inflorescence and macerated oils based on HS-SPME coupled to GC-MS and LC-HRMS (q-exactive orbitrap®) approach.

PubMed

Calvi, Lorenzo; Pentimalli, Daniela; Panseri, Sara; Giupponi, Luca; Gelmini, Fabrizio; Beretta, Giangiacomo; Vitali, Davide; Bruno, Massimo; Zilio, Emanuela; Pavlovic, Radmila; Giorgi, Annamaria

2018-02-20

There are at least 554 identified compounds in C. sativa L., among them 113 phytocannabinoids and 120 terpenes. Phytocomplex composition differences between the pharmaceutical properties of different medical cannabis chemotype have been attributed to strict interactions, defined as 'entourage effect', between cannabinoids and terpenes as a result of synergic action. The chemical complexity of its bioactive constituents highlight the need for standardised and well-defined analytical approaches able to characterise the plant chemotype, the herbal drug quality as well as to monitor the quality of pharmaceutical cannabis extracts and preparations. Hence, in the first part of this study an analytical procedures involving the combination of headspace-solid-phase microextraction (HS-SPME) coupled to GC-MS and High Resolution Mass-Spectrometry LC-HRMS (Orbitrap ® ) were set up, validated and applied for the in-depth profiling and fingerprinting of cannabinoids and terpenes in two authorised medical grade varieties of Cannabis sativa L. inflorescences (Bedrocan ® and Bediol ® ) and in obtained macerated oils. To better understand the trend of all volatile compounds and cannabinoids during oil storage a new procedure for cannabis macerated oil preparation without any thermal step was tested and compared with the existing conventional methods to assess the potentially detrimental effect of heating on overall product quality. Copyright © 2017 Elsevier B.V. All rights reserved.

Genetic and metabolite diversity of Sardinian populations of Helichrysum italicum.

PubMed

Melito, Sara; Sias, Angela; Petretto, Giacomo L; Chessa, Mario; Pintore, Giorgio; Porceddu, Andrea

2013-01-01

Helichrysum italicum (Asteraceae) is a small shrub endemic to the Mediterranean Basin, growing in fragmented and diverse habitats. The species has attracted attention due to its secondary metabolite content, but little effort has as yet been dedicated to assessing the genetic and metabolite diversity present in these populations. Here, we describe the diversity of 50 H. italicum populations collected from a range of habitats in Sardinia. H. italicum plants were AFLP fingerprinted and the composition of their leaf essential oil characterized by GC-MS. The relationships between the genetic structure of the populations, soil, habitat and climatic variables and the essential oil chemotypes present were evaluated using Bayesian clustering, contingency analyses and AMOVA. The Sardinian germplasm could be partitioned into two AFLP-based clades. Populations collected from the southwestern region constituted a homogeneous group which remained virtually intact even at high levels of K. The second, much larger clade was more diverse. A positive correlation between genetic diversity and elevation suggested the action of natural purifying selection. Four main classes of compounds were identified among the essential oils, namely monoterpenes, oxygenated monoterpenes, sesquiterpenes and oxygenated sesquiterpenes. Oxygenated monoterpene levels were significantly correlated with the AFLP-based clade structure, suggesting a correspondence between gene pool and chemical diversity. The results suggest an association between chemotype, genetic diversity and collection location which is relevant for the planning of future collections aimed at identifying valuable sources of essential oil.

Identification of Pathogenic Fusarium spp. Causing Maize Ear Rot and Potential Mycotoxin Production in China

PubMed Central

Duan, Canxing; Qin, Zihui; Yang, Zhihuan; Li, Weixi; Sun, Suli; Zhu, Zhendong; Wang, Xiaoming

2016-01-01

Ear rot is a serious disease that affects maize yield and grain quality worldwide. The mycotoxins are often hazardous to humans and livestock. In samples collected in China between 2009 and 2014, Fusarium verticillioides and F. graminearum species complex were the dominant fungi causing ear rot. According to the TEF-1α gene sequence, F. graminearum species complex in China included three independent species: F. graminearum, F. meridionale, and F. boothii. The key gene FUM1 responsible for the biosynthesis of fumonisin was detected in all 82 F. verticillioides isolates. Among these, 57 isolates mainly produced fumonisin B1, ranging from 2.52 to 18,416.44 µg/g for each gram of dry hyphal weight, in vitro. Three different toxigenic chemotypes were detected among 78 F. graminearum species complex: 15-ADON, NIV and 15-ADON+NIV. Sixty and 16 isolates represented the 15-ADON and NIV chemotypes, respectively; two isolates carried both 15-ADON and NIV-producing segments. All the isolates carrying NIV-specific segment were F. meridionale. The in vitro production of 15-ADON, 3-ADON, DON, and ZEN varied from 5.43 to 81,539.49; 6.04 to 19,590.61; 13.35 to 19,795.33; and 1.77 to 430.24 µg/g of dry hyphal weight, respectively. Altogether, our present data demonstrate potential main mycotoxin production of dominant pathogenic Fusarium in China. PMID:27338476

Phenolic chemistry of the seagrass Zostera noltei Hornem. Part 1: First evidence of three infraspecific flavonoid chemotypes in three distinctive geographical regions.

PubMed

Grignon-Dubois, Micheline; Rezzonico, Bernadette

2018-02-01

The flavonoid content of Zostera noltei leaves was investigated over a broad spatial scale using chromatographic and spectroscopic techniques (HPLC-DAD, LC/MS and NMR). Samples were collected at fifteen localities covering Mediterranean Sea and NE Atlantic coast, and representative of three types of coastal ecosystems: mesotidal bays, coastal lagoons, and open-sea. Three geographically distinct flavonoid chemotypes were identified on the basis of their respective major compound. One is characterized by apigenin 7-sulfate (Eastern part of Gulf of Cadiz), one by diosmetin 7-sulfate (French Atlantic coast and Mediterranean Sea), and the third contained similar quantities of the above two compounds (Mauritania and South Portugal). Our results show that metabolomic profiling using a combination of analytical techniques is a tool of choice to characterize chemical phenotype accurately. This work emphasizes for the first time the spatial variability in the flavonoid chemistry of Z. noltei throughout Atlantic and Mediterranean range, and constitutes the first report of chemical races in the Zosteraceae family. This infraspecific chemical differentiation should be considered when dealing with the role of Z. noltei in coastal ecosystems or in the selection of the best population donor for Z. noltei beds restoration. Combined with molecular identification, phenolic fingerprinting might be helpful to elucidate the evolutionary history of Z. noltei. Copyright © 2017 Elsevier Ltd. All rights reserved.

Metabolic chemotypes of CITES protected Dalbergia timbers from Africa, Madagascar, and Asia.

PubMed

McClure, Pamela J; Chavarria, Gabriela D; Espinoza, Edgard

2015-05-15

The genus Dalbergia includes approximately 250 species worldwide. Of these, 58 species are of economic importance and listed under CITES. Identification of illegal transnational timber trade is a challenge because logs or boards lack the typical descriptors used for species identification such as leaves and flowers; therefore, frequently the lowest taxonomic determination of these tree byproducts is genus. In this study, we explore the use of Direct Analysis in Real Time (DART) Time-Of-Flight Mass Spectrometry (TOFMS) in making species determinations of protected Dalbergia trees from Africa, Madagascar, and Asia. Metabolic profiles were collected using DART TOFMS from the heartwood of seven species and the sapwood of 17 species of Dalbergia. Also included in this study are 85 Dalbergia heartwood samples from Madagascar that were only identified to genus. In all, 21 species comprising 235 specimens were analyzed, the metabolic chemotypes were interpreted, and the spectra were analyzed using chemometric tools. Dalbergia cochinchinensis and Dalbergia spp. from Madagascar (both CITES Appendix II) could be differentiated from each other and from the non-protected Dalbergia latifolia and Dalbergia melanoxylon. DART TOFMS is a valuable high-throughput tool useful for making phytochemical classifications of Dalbergia spp. The data produced allows the protected Dalbergias from Madagascar to be distinguished and can differentiate closely related rosewood trees. Published in 2015. This article is a U.S. Government work and is in the public domain in the USA.

Analysis of deoxynivalenol and deoxynivalenol-3-glucosides content in Canadian spring wheat cultivars inoculated with Fusarium graminearum.

PubMed

Amarasinghe, Chami C; Simsek, Senay; Brûlé-Babel, Anita; Fernando, W G Dilantha

2016-07-01

Contamination of wheat grains with Fusarium mycotoxins and their modified forms is an important issue in wheat industry. The objective of this study was to analyse the deoxynivalenol (DON) and deoxynivalenol-3-glucosides (D3G) content in Canadian spring wheat cultivars grown in two locations, inoculated with a mixture of 3-acetyldeoxynivalenol (3-ADON)-producing Fusarium graminearum strains and a mixture of 15-acetlyldeoxynivalenol (15-ADON)-producing F. graminearum strains. According to the analysis of variance, significant differences were observed among the cultivars for Fusarium head blight (FHB) disease index, Fusarium-damaged kernel percentage (%FDK), DON content and D3G content. When the effect of chemotype was considered, significant differences were observed for FHB disease index, FDK percentage and DON content. The D3G content and D3G/DON ratio were not significantly different between the chemotypes, except for D3G content at the Winnipeg location. The Pearson correlation coefficient between DON and D3G was 0.84 and 0.77 at Winnipeg and Carman respectively. The highest D3G/DON ratio was observed in cultivars Carberry (44%) in Carman and CDC Kernen (63.8%) in Winnipeg. The susceptible cultivars showed lower D3G/DON ratio compared with the cultivars rated as moderately resistant and intermediate. The current study indicated that Canadian spring cultivars produce D3G upon Fusarium infection.

Targeting the NF-κB and mTOR pathways with a quinoxaline urea analog that inhibits IKKβ for pancreas cancer therapy.

PubMed

Radhakrishnan, Prakash; Bryant, Vashti C; Blowers, Elizabeth C; Rajule, Rajkumar N; Gautam, Nagsen; Anwar, Muhammad M; Mohr, Ashley M; Grandgenett, Paul M; Bunt, Stephanie K; Arnst, Jamie L; Lele, Subodh M; Alnouti, Yazen; Hollingsworth, Michael A; Natarajan, Amarnath

2013-04-15

The presence of TNF-α in approximately 50% of surgically resected tumors suggests that the canonical NF-κB and the mTOR pathways are activated. Inhibitor of IκB kinase β (IKKβ) acts as the signaling node that regulates transcription via the p-IκBα/NF-κB axis and regulates translation via the mTOR/p-S6K/p-eIF4EBP axis. A kinome screen identified a quinoxaline urea analog 13-197 as an IKKβ inhibitor. We hypothesized that targeting the NF-κB and mTOR pathways with 13-197 will be effective in malignancies driven by these pathways. Retrospective clinical and preclinical studies in pancreas cancers have implicated NF-κB. We examined the effects of 13-197 on the downstream targets of the NF-κB and mTOR pathways in pancreatic cancer cells, pharmacokinetics, toxicity and tumor growth, and metastases in vivo. 13-197 inhibited the kinase activity of IKKβ in vitro and TNF-α-mediated NF-κB transcription in cells with low-μmol/L potency. 13-197 inhibited the phosphorylation of IκBα, S6K, and eIF4EBP, induced G1 arrest, and downregulated the expression of antiapoptotic proteins in pancreatic cancer cells. Prolonged administration of 13-197 did not induce granulocytosis and protected mice from lipopolysaccharide (LPS)-induced death. Results also show that 13-197 is orally available with extensive distribution to peripheral tissues and inhibited tumor growth and metastasis in an orthotopic pancreatic cancer model without any detectable toxicity. These results suggest that 13-197 targets IKKβ and thereby inhibits mTOR and NF-κB pathways. Oral availability along with in vivo efficacy without obvious toxicities makes this quinoxaline urea chemotype a viable cancer therapeutic.

Identification of Ponatinib as a potent inhibitor of growth, migration and activation of neoplastic eosinophils carrying FIP1L1-PDGFRA

PubMed Central

Sadovnik, Irina; Lierman, Els; Peter, Barbara; Herrmann, Harald; Suppan, Verena; Stefanzl, Gabriele; Haas, Oskar; Lion, Thomas; Pickl, Winfried; Cools, Jan; Vandenberghe, Peter; Valent, Peter

2015-01-01

In chronic eosinophilic leukemia (CEL), the transforming oncoprotein FIP1L1-PDGFRA is a major target of therapy. In most patients, the tyrosine kinase inhibitor (TKI) imatinib induces complete remission. For patients who are intolerant or resistant, novel TKI have been proposed. We examined the in vitro effects of 14 kinase blockers on growth and function of EOL-1 cells, a FIP1L1-PDGFRA+ eosinophil cell line. Major growth-inhibitory effects were seen with all PDGFR-blocking agents, with IC50 values in the low nM-range: ponatinib: 0.1-0.2 nM, sorafenib: 0.1-0.2 nM, masitinib: 0.2-0.5 nM, nilotinib: 0.2-1 nM, dasatinib: 0.5-2 nM, sunitinib: 1-2 nM, midostaurin: 5-10 nM. These drugs were also found to block activation of PDGFR-downstream signaling molecules, including Akt, S6, and STAT5 in EOL-1 cells. All effective TKI produced apoptosis in EOL-1 cells as determined by microscopy, Annexin-V/PI, and caspase-3-staining. In addition, PDGFR-targeting TKI were found to inhibit cytokine-induced migration of EOL-1 cells. In all bioassays employed, ponatinib was found to be the most potent compound in EOL-1 cells. In addition, ponatinib was found to downregulate expression of the activation-linked surface antigen CD63 on EOL-1 cells, and to suppress growth of primary neoplastic eosinophils. We also examined drug effects on Ba/F3 cells expressing two clinically relevant imatinib-resistant mutant-forms of FIP1L1-PDGFRA, namely T674I and D842V. Strong inhibitory effects on both mutants were only seen with ponatinib. In summary, novel PDGFR-targeting TKI may be alternative agents for the treatment of patients with imatinib-resistant CEL. Although several different PDGFR-targeting agents are effective, the most potent drug appears to be ponatinib. PMID:24407160

Characterization of the biological activity of a potent small molecule Hec1 inhibitor TAI-1

PubMed Central

2014-01-01

Background Hec1 (NDC80) is an integral part of the kinetochore and is overexpressed in a variety of human cancers, making it an attractive molecular target for the design of novel anticancer therapeutics. A highly potent first-in-class compound targeting Hec1, TAI-1, was identified and is characterized in this study to determine its potential as an anticancer agent for clinical utility. Methods The in vitro potency, cancer cell specificity, synergy activity, and markers for response of TAI-1 were evaluated with cell lines. Mechanism of action was confirmed with western blotting and immunofluorescent staining. The in vivo potency of TAI-1 was evaluated in three xenograft models in mice. Preliminary toxicity was evaluated in mice. Specificity to the target was tested with a kinase panel. Cardiac safety was evaluated with hERG assay. Clinical correlation was performed with human gene database. Results TAI-1 showed strong potency across a broad spectrum of tumor cells. TAI-1 disrupted Hec1-Nek2 protein interaction, led to Nek2 degradation, induced significant chromosomal misalignment in metaphase, and induced apoptotic cell death. TAI-1 was effective orally in in vivo animal models of triple negative breast cancer, colon cancer and liver cancer. Preliminary toxicity shows no effect on the body weights, organ weights, and blood indices at efficacious doses. TAI-1 shows high specificity to cancer cells and to target and had no effect on the cardiac channel hERG. TAI-1 is synergistic with doxorubicin, topotecan and paclitaxel in leukemia, breast and liver cancer cells. Sensitivity to TAI-1 was associated with the status of RB and P53 gene. Knockdown of RB and P53 in cancer cells increased sensitivity to TAI-1. Hec1-overexpressing molecular subtypes of human lung cancer were identified. Conclusions The excellent potency, safety and synergistic profiles of this potent first-in-class Hec1-targeted small molecule TAI-1 show its potential for clinically utility in anti-cancer treatment regimens. PMID:24401611

Discovery of Novel ROCK1 Inhibitors via Integrated Virtual Screening Strategy and Bioassays

PubMed Central

Shen, Mingyun; Tian, Sheng; Pan, Peichen; Sun, Huiyong; Li, Dan; Li, Youyong; Zhou, Hefeng; Li, Chuwen; Lee, Simon Ming-Yuen; Hou, Tingjun

2015-01-01

Rho-associated kinases (ROCKs) have been regarded as promising drug targets for the treatment of cardiovascular diseases, nervous system diseases and cancers. In this study, a novel integrated virtual screening protocol by combining molecular docking and pharmacophore mapping based on multiple ROCK1 crystal structures was utilized to screen the ChemBridge database for discovering potential inhibitors of ROCK1. Among the 38 tested compounds, seven of them exhibited significant inhibitory activities of ROCK1 (IC50 < 10 μM) and the most potent one (compound TS-f22) with the novel scaffold of 4-Phenyl-1H-pyrrolo [2,3-b] pyridine had an IC50 of 480 nM. Then, the structure-activity relationships of 41 analogues of TS-f22 were examined. Two potent inhibitors were proven effective in inhibiting the phosphorylation of the downstream target in the ROCK signaling pathway in vitro and protecting atorvastatin-induced cerebral hemorrhage in vivo. The high hit rate (28.95%) suggested that the integrated virtual screening strategy was quite reliable and could be used as a powerful tool for identifying promising active compounds for targets of interest. PMID:26568382