ANALYTICAL CHEMISTRY/MEDICINAL CHEMISTRY427 doi:10.2533/chimia.2007.427 CHIMIA 2007, 61,No. 7/8
Analytical Chemistry 41 Analytical Chemistry 42
Sensor Arrays forthe Analysis of Sugars in Aqueous Solution Investigation of Hypericum species by LC/MS
Friederike Zaubitzer,Kay Severin G. Sibailly,K.Ndjoko,A.Marston, andK.Hostettmann* Institutdes Sciences et Ingénerie Chimiques, Ecole Polytechnique Fédérale LaboratoryofPharmacognosyand Phytochemistry, School of de Lausanne (EPFL),CH-1015 Lausanne, Switzerland Pharmaceutical Sciences,University of Geneva, University of Lausanne, Fluorescence sensors for sugars havereceived enormous interestinrecent Quai Ernest-Ansermet 30,CH-1211 Geneva 4, Switzerland years. Most efforts have focused on the development of sensors with a highly selectivityfor aparticular sugar. This is generally accomplished with thehelp of synthetic receptors, which display ahigh specificity. An interest- Acharacteristic of plant species fromthe genus Hypericum (Hypericaceae) ing alternative is the utilization of asensor array technology. In asensor is the presence of pigments belonging to the class of naphthodianthrones. array, severalnon-specific sensorsare combined and the analyteisthen Theseplants havemany traditional uses and, notably, Hypericum perfora- identified with patternrecognition tools. This technique has successfully tum is employedfor the treatment of mild depression. Severalstudiesdeal been appliedfor different analytical problems [1], but the utilization of sen- with the activitiesofthe numerous constituentsofthe genus or compare sor arrays for sugars is virtually unexplored [2]. We describeasensor array, different Hypericum species [1,2]. Thegenus is alsoreputed forcases of which is based on the reversible coupling of fluorescent hydrazides with the poisoningincattle(hypericism) which alsohave their origin in the presence aldehyde group of reducing sugars. of thesecompounds.Morerecently, the naphthodianthrones have assumed importance forthe photodynamic therapy of cancer. O O N In order to determine the relative contents of hypericin and pseudohypericin Fluorophore NH NH + O Sugar Fluorophore N Sugar 2 H Fluorophore in theseplants,extraction of several species of St.-John's wortwas per- Fig.1.: Schematic representation of afluorescence sensor for sugars formedbydifferent proceduresinordertooptimizethe yield of the active constituents. Discrimination is achieved by exploitation of differences in fluorescence HPLC-UV/DAD and HPLC-MS methods werethen developed forthe emission intensities whichdependonthe nature of the dye-sugar derivate analysis of naphthodianthrones in the plants. It was found that Hypericum and the reaction equilibria in solution. calycinum L. does not contain this classofcompounds.
[1]K.J.Albert, N. S. Lewis, C. L. Schauer, G. A. Sotzing, S. E. Stitzel, [1] FicoG., VitaliniS., Colombo N.,TomeF., Hypericum perforatum L.,H. T.P. Vaid,D.R.Walt, Chem.Rev. 2000,100, 2595. maculatum Crantz. ,H.calycinum L .and H. pulchrum L .: phytochemical [2] J. W. Lee, J.-S. Lee, Y.-T. Chang, Angew. Chem. Int. Ed. 2006,45, andmorphological studies., 2006,1,1129-1132. 6485. [2]OzturkY., Testing the andipressant effects of Hypericum specieson animal models,Pharmacopsychiatry, 1998,31, 37.
Medicinal Chemistry 43 Medicinal Chemistry 44
Thermodynamic and KineticConsiderations of theBinding Processof Novelguanidine-type 5-HT5A receptorantagonists MAG-Antagonists Jens-Uwe Peters ,* Alexander Alanine,AndreAlker,Francesca Blasco, StefanieMesch,DanielStrasser, Morena Spreafico, BrianCutting, Arnulf Dorn, Alain Gast, Luca Gobbi,Sabine Kolczewski, Nicole SachinShelke, Oliver Schwardt,Beat Ernst Kratochwil,Thomas Lübbers, PariMalherbe, Eric Prinssen, Diana Schuhbauer,Lucinda Steward Institute of MolecularPharmacy,University of Basel, Klingelbergstr. 50, 4050 Basel, Switzerland *Discovery Chemistry, F. Hoffmann-La Roche Ltd, CH-4070 Basel
Theinjured adult mammalian central nervous system is an inhibitoryenvi- ronment foraxon regeneration due to specific inhibitoryproteins.The mye- Cl Cl lin-associated glycoprotein (MAG)[1] wasidentified as oneoftheseneurite NH Cl NH NH outgrowth inhibitory proteins [2]. It belongs to the siglec family (sialic-acid N N F H N NH N N bindingimmunoglobulin-like lectin). In earlier studies,weidentified the 2 H F lead structure 1 [3], which was further optimized yielding antagonists with 1 2 3 nM affinities. K i (5-HT 5A)=160 nM K i (5-HT 5A)=2nM K i (5-HT 5A)=3nM screening hit brain/plasma ~0.2 brain/plasma ~4 Cl H N OH COOH Theexpression of the 5-HT receptor in the limbic brain areas suggestsa OH 5A potential role in the modulation of psychiatric diseases. 1 Howeveruntil re- O O O AcHN cently, no selective 5-HT5A receptor ligands were available to study its HO pharmacology in detail. We screened the Roche compound librarytoiden- tifyselective antagonists forthis target, and found several guanidines such 1 as 1 among the mostselective compounds.Asystematic exploration of small substituents (Cl, Me,MeO,F)around the core structureled to 2 with
Thekinetic and thermodynamic propertiesofthese high affinity ligands potent 5-HT5A antagonistic affinity in vitro ,and improved selectivity, apart wereelucidatedbyBiacorestudies.Inaddition, the binding mode wasex- from5-HT 7 .Compound 2 had good PK properties, however alow brain- amined through STDNMR experiments and docking studies. plasma ratio. Thebrain penetration was improved by the introduction of electron-withdrawing substituents,which afforded acompound with in- [1]Quarles, R. H., J. Neurochem. 2007, 100,1431. creased lipophilicity,and reduced basicity, 3 .The series refinement and [2]Crocker,R.H., Curr.Opin. Struct.Biol. 2002, 12,609. structure activity relationship elucidatedinprogressing from the initialhit 1 [3]Shelke, S.,Gao,G-P., Mesch, S.,Gäthje, H.,Kelm, S.,Schwardt, O., to lead compound 3 will be furtherdescribed in the presentation. Ernst, B., Bioorg. Med. Chem, in press . [1]Thomas,D.R. Pharmacol.Ther. 2006, 111(3), 707-714. MEDICINAL CHEMISTRY428 CHIMIA 2007, 61,No. 7/8
Medicinal Chemistry 45 Medicinal Chemistry 46
Identification of NovelMulti-functional Compounds for the Treatment Medicinal chemistryefforts towardsthe identificationand development of some Aging Related NeurodegenerativeDiseases of inhibitorsofphosphatidylinositol 3-kinases (PI3Ks)and related proteinkinases forcancer treatment. Juan Bravo,Saviana Di Giovanni,Delphine Cressend, Francesca Bertolini; Laura Novaroli,Antoine Daina,Marianne Reist, Pierre-Alain Carrupt Frédéric Stauffer ,CarlosGarcia-Echeverria, Pascal Furet, Hans-GeorgCapraro,Philipp Holzer,Christian Schnell, Unité de Pharmacochimie, Section dessciences pharmaceutiques, ChristineM.Fritsch &MichelMaira. Université de Genève,Université de Lausanne, Quai Ernest-Ansermet 30, CH-1211 Genève 4, Suisse Novartis Institutes forBioMedical Research, Klybeckstrasse 141, 4057 Basel, Switzerland. Aging related neurodegenerative disorders such as Parkinsondisease (PD) and Alzheimers disease(AD) arethe result of multiple pathophysi- Constitutive activation of the PI3K-pathwayseemstobeaprerequisite for a ological pathways that contribute to theneurodegenerativecascade. Hence, wide spectrumofcancers, either by loss /mutationsofPTEN,acquisition of multi-functionaldrug candidatesabletointeract with severaltargets areof activating mutations in the PI3K catalytic subunit, or amplification /over- great interest forthe treatment of such diseases.Therefore,anexperimental expression of receptor tyrosine kinases upstream of PI3K.Inthisrespect, andvirtualscreening pathwaytogeneratemulti-functionalhits promising components of the PI3K/PKB/mTor pathway such as membersofthe classI forthe treatment of PD or AD was suggested[1]. PI3Ks represent wellvalidated therapeutic targetsfor thediscoveryand de- Among the numerous potentialtargets,fivewereselected; two are velopment of new anticancer drugs.Although theyhave sub-optimal phar- common to both diseases,namely monoamine oxidaseB(MAO B) and oxi- maceutical properties,PI3Kinhibitors like the fungal metabolite wortman- dativestress, and threeare specificfor onlyone of thetwo disorders, nin and the morpholino derivative LY294002 have shown that this classof catechol-O-methyltransferase (COMT) forPDand acetylcholinesterase lipid kinasesis"drug-able".Inactivators of the TORC1 complex- (AChE)aswellas -amyloid deposition forAD, respectively. mTor/Raptor-, such as the rapamicinederivative RAD001, have shown anti- Suitable experimental and virtual screening methods to rapidly test cancer activity in clinical trials.Inaddition to TORC1,the TORC2 complex pre-focused compound librariesweredeveloped and validated. Thepro- -mTor/Rictor-has recently been linked to PKBphosphorylation and activa- posed rationalscreening strategy wasappliedtoalibrary of naturalcom- tion.1 pounds and some focusedsynthetic libraries, leading to some interesting Our medicinalchemistry efforts using the privilege kinaseinhibitor scaffold multi-functionalhits.Refinedmolecularmodelling approaches were also imidazo[4,5-c]quinoline to identify andoptimizenew inhibitors of the used to identifytheir binding modes and to suggestsome guidelinesfor the PI3K/PKB/mTor-pathwaywill be disclosed.From this chemotype,aclinical pharmacomodulation of retained hits in order to obtain multifunctional vir- candidatehas been selected. This inhibitor,which has suitablepharmacol- tual lead compounds. ogical properties forclinical development, shows an efficient controlofthe PI3K-pathway in tumor cells by inhibiting the phosphorylation and activa- tion of PKB in cellularand in vivo settings. [1]L.Novaroli et al, Chimia. 2005, 59,315-320. [1] Sarbassov, D. D.;Guertin, D. A.,; Ali,S.M.; Sabatini, D. M.; Science 2005, 307,1098.
Medicinal Chemistry 47 Medicinal Chemistry 48
Receptor-MediatedTargetingofMetastaticMelanomawith VesicleFormation in Aqueous Solution Radiolabeled DOTA- -MSH Analogs Driven by Selective Non-Covalent Interactions
Jean-Philippe Bapst ,Martine Calame-Christe,Heidi Tanner JessicaGrun a ,Corinne Vebert*b ,Matteo Conzaa , and Alex N. Eberle Wolfgang Meierb ,Helma Wennemers* a
University HospitalBasel,Department of Research,Hebelstrasse 20, a OrganicChemistry,University of Basel, St.Johanns-Ring 19,CH-4056 Basel, Switzerland CH-4031 Basel, Switzerland b Physical Chemistry, UniversityofBasel,Kingelbergstr.80, CH-4056 Basel, Switzerland
Melanotic andamelanoticmelanomas expressreceptorsfor -melanocyte- TheWennemersgroup has recently developedtwo-armed diketopiperazine stimulating hormone ( -MSH;receptor name: MC1R) .Radiolabeled - receptorsthat bind peptides with high bindingselectivities andaffinities.[1] MSHanalogs arepotentialcandidates forreceptor-mediated melanomatar- Thehighly selective intermolecularinteraction between the diketopiperazine geting (diagnosis and therapy).Several short -MSH peptides werede- receptor 1 and the peptide,Ac-D -Val- D -Val- D -His-resin, was used to induce signed and testedinthe past, which showed high affinity forthe MC1R in supramolecular assemblies by functionalizingthe peptidewith aPEG-chain. vitro ,aswell as agood incorporation in tumor xenografts in vivo,but also In chloroform, diketopiperazine receptor 1 mixed with the peptide-PEG considerable uptake by the kidneys. conjugate 2 [2], formsagel. In aqueous solution, the formation of vesicles 4 5 7 was observed and studied using dynamic lightscattering(DLS),transmis- We now investigate glycosylated analogs of [Nle ,Asp ,D-Phe ]- -MSH4-11 (NAPamide) [1], as glycosylation had been showntoimprove tumor-to- sion electron (TEM)and atomic forcemicroscopy (AFM), surface pressure kidney ratios in the caseofsomatostatin. Carbohydrate moieties such as measurements, as well as,NMR titration. glucose, galactoseand maltotriosewereintroduced at various positions on Phe Tyr(Dye) O O H H the MSHpeptide carrying the metalchelatorDOTA(1,4,7,10- N N N N 111 H H tetraazacyclododecane-1,4,7,10-tetraacetic acid) forlabeling with In.The O O Gln(Trt) N H O O H H peptides wereevaluated in vitro forMC1Rbindingand cellular localization, 1 O O N N (OCH CH ) -OCH N N 2 2 16 3 H N Gln(Trt) H H and in vivo fortissuedistribution. Thetumor-to-kidneyratio forGal- O O O O H H N N N 2 NAPamide(1.85),bearinganN-terminal galactosemoiety, wascomparable N N H H N O O with that of NAPamide (1.92).Other glycopeptides showed verygood bind- Phe Tyr(Dye) H ing affinitiesbut lowerselectivity in vivo. This workisthe firstexample of vesicle formationbased on selective non- Additionally, aclassofnon-glycosylated dimericderivatives,bearing one or covalentinteractions. We envisionthis concepttobeofinterest for encapsu- two moietiesofthe chelator complex, was developedand is currently being lation and drug delivery. tested. [1] (a)H.Wennemers,M.Conza, M. Nold, P. Krattiger, Chem.Eur.J. 2001, 7 ,3342; (b) M. Conza, H. Wennemers, J. Org. Chem. 2002, 67,2696; (c)M.Conza, H. Wennemers, [1]Froidevaux S, Calame-Christe M, Tanner H, Sumanovski L, Eberle Chem. Commun. 2003,866;(d) P. Krattiger,H.Wennemers, Synlett 2005, 4 ,706. AN. JNuclMed. 2002, 43,1699 [2]J.Grun, J. D. Revell,M.Conza, H. Wennemers, Bioorg. Med.Chem. 2006, 14,6197. MEDICINAL CHEMISTRY429 CHIMIA 2007, 61,No. 7/8
Medicinal Chemistry 49 Medicinal Chemistry 50
HypermodifiedEpothilone Analogs as New LeadStructures forAnti- Synthesis of aC-linked Disaccharide Analogue of theThomsen- Cancer DrugDiscovery Friedenreich (TF)-Epitope andFormationofaClustery form as aPotential Anticancer Vaccine ChristianKuzniewski ,Karl-HeinzAltmann Loay Awad,and Pierre Vogel*
Department of Chemistryand Applied Biosciences,ETH Zürich, LGSA, BCH,EPFL, CH-1015 Lausanne, Switzerland Wolfgang-Pauli-Strasse 10, HCI, CH-8093 Zurich, Switzerland TheThomsen-Friedenreich antigen (T antigen) is acancer-associated disac- Epothilones aremicrotubule-stabilizing agents with potent in vitro and in charide whichplays an important role in tumor cell-cellrecognition. The vivo antitumor activity. Although the SAR of thishighly promising com- immunodominant partofthe Tantigen consists of the disaccharide poundclasshas been extensively investigated, specific aspectsstill remain Gal 1 3GalNAc Olinked to serine or threonine. Thegreat potential of unaddressed [1] .Benzimidazole-basedanalogsofepothilonesexhibit en- clusteredantigenmotifs such as 1 forantitumorvaccines has been demon- hanced antiproliferative activity againstdrug-sensitive cancer cells;however strated. [1] they alsoshow increasedsusceptibility to P-gp170-mediated drug efflux[1,2] . In contrast, the corresponding cyclopropane analogs arepoor substrates for P-gp-mediateddrugefflux[3] .The major objective of this project is the de- velopment of an efficient synthesis forepothilone analogues of type 1 ,that allow for the combinedexploitation of the potent biological activity of the 3-deoxy trans-epothilone Ascaffold and an activity-enhancing dimethyl- benzimidazole side chain. To circumvent drug efflux, the epoxide moiety is C-linked disaccharide analogues offerstability towards hydrolysis which is replaced by an isostericcyclopropane ring. Thesestructuralchanges lead to catalysed by ubiquitous glycosidases.Wewishtopresent here the extension hypermodifiedanalogues with little structural resemblance to the original of our previous efforts [2] towards the synthesis of C-disaccharide analogues epothilone scaffold. Thesynthesis of 1 is based on the assembly of frag- of the Tantigen based on aBaylis-Hillman type of condensationbetween a [3-4] ments 2 and 3 via an esterification/ring-closing-metathesis sequence. The D -galactose-derived aldehydeand isolevoglucosenone. preparation of thesebuilding blocks andtheir elaboration into targetstruc- ture 1 willbedescribed in detail. [1]S.D.Kuduk, J. B. Schwarz, X.-T.Chen,P.W.Glunz, D. Sames,G.Ra- gupathi, P. O. Livingston, S. J. Danishefsky, J. Am.Chem. Soc. 1998, 120, 12474. HO N TBSO N [2]Y.-H. Zhu, P. Vogel, Synlett 2001,79 . O OH N [3]Y.-H. Zhu, P. Vogel, Tetrahedron Lett. 1998, 39,31; Y.-H.Zhu, R. De- N O mange, P. Vogel, Tetrahedron: Asymmetry 2000, 11,263; O O OH [1]F.Cachoux et al. , Angew. Chem. Int. Ed. 2005, 44,7469. O [2]F.Cachoux et al., ChemBioChem 2006, 7 ,54. [3]K.C.Nicolaou et al. , J. Am.Chem. Soc. 2001, 123,9313.
Medicinal Chemistry 51 Medicinal Chemistry 52
Vitamin B as atrojan-horseintherapy 12 From ASAtoSAM: Introducing the PAMPAdiagnostic mode
PilarRuiz-Sánchez,BernhardSpingler,Roger Alberto Frank Senner University of Zürich,Winterthurerstr.190, CH-8057Zürich, Switzerland F. Hoffmann-La Roche Ltd.,Grenzacherstrasse,4070 Basel, Switzerland We have synthesized and characterized aseriesofPt(II)complexes contain- PAMPA is a1st line permeability screen forpharmaceutical drugs [1-7]. ing vitamin B as aligand.1 Theprecursors [PtCl L]- {L=NH ,antibiotics 12 3 3 When introduced firstin1998 it has been used to predict oral absorption in (norfloxacin, ciprofloxacin) or fluorescentmarkers (dansylimidazole,dan- humans. Later on its application area hasbeen extended to blood brain bar- syl-L-lysine )}, react with thecyanide of vitamin B to form the{Co- 12 rier (BBB) penetrationand even skin permeation[8]. C N-Pt} conjugates, with abehaviour similartothatofcisplatin (example: Nowadays ashift fromAllScreenAll (ASA) to Selected Assays and compound 1 ). Molecules (SAM) is becoming moreand moreimportant in order to sup- Enzymatic corrinoid adenosylation assays2 of theseadducts showed recogni- tion andconversion to adenosylcobalamin and releaseofPt(II)species. portfasterdecisionmaking in early drug development (LI, LO,CLS). Thesenovel derivatives can be used forspecific targeting of cancer cells or PAMPA diagnostic mode is such an examplefor SAM. By applying a donor pH profile and acceptor sink conditions (blood pH 7.4, protein bind- bacterialinfections,since fast proliferationcells arehighB12 consumers. Preliminary bacterialand cancer celluptake studieswill be discussed. ingeffects) lowpermeableand lowsolublemolecules arecharacterized in detail. Further extensions arepossible. Thekeywords are: excipient screen- Cl L ing and reduction of sample consumption (DiFi plates). LCPt l H NOC 2 N CONH 2 H NOC CH 2 3 NH3 anticanceractivity C CH3 H C [1]Kansy, Manfred; Senner,Frank; Gubernator,Klaus,J.ofMed.Chem. 3 CONH N N 2 O H 3 C H Co F COOH 1998,41(7),1007. N N H NOC CH3 N N [2]Avdeef,Alex, Cur.Top.inMed.Chem. 2001,1(4), 277. 2 N antibiotic activity CH3 H 3 C [3]Wohnsland, Frank; Faller, Bernard, J. of Med. Chem. 2001,44(6),923. CH3 Norfloxacin [4]Sugano Kiyohiko; Nabuchi Yoshiaki; Machida Minoru; AsoYoshinori, CONH 2 O CH HN N 3 N H C Int. J. of Pharm. 2003,257(1-2), 245. 3 HO O N CH H 3 N S fluorescent [5]Kansy, Manfred; Avdeef,Alex; Fischer,Holger, Drug Disc. Today: O O N O P O Dansylimidazole Tech. 2004,1(4), 349. O O OH [6]Avdeef,Alex, Exp. Op.onDrugMet.&Tox. 2005,1(2), 325. 1 [7] Bendels,Stefanie; Tsinman, Oksana; Wagner, Bjoern; Lipp, Dana;Par- [1]Mundwiler,S.; Spingler,B.; Kurz, P.;Kunze, S.;Alberto,R. Angew. rilla,Isabelle;Kansy,Manfred; Avdeef,Alex, Pharm.Res. 2006, Chem.Int.Edit. 2005, 11,4089. 23(11),2525. [2]Fonseca, M.V.;Escalante-Semerena, J.C. J. Biol.Chem. 2001, 276, [8]Ottaviani, Giorgio; Martel, Sophie; Carrupt,Pierre-Alain, J. of Med. 32101. Chem. 2006,49(13),3948. MEDICINAL CHEMISTRY430 CHIMIA 2007, 61,No. 7/8
Medicinal Chemistry 53 Medicinal Chemistry 54
Orexin Receptor Antagonists:ANew TherapeuticPrinciple in Efficient ligand affinity calculations using Neurology and Psychiatry? novelcomputational methods
Hamed Aissaoui, Christoph Boss, Thierry Sifferlen,Markus Gude, Thomas HolmfridurB.Thorsteinsdottir,Michael Podvinec, Weller,Catherine Brisbare-Roch, François Jenck, John Gatfield, Roberto Torsten Schwede, Markus Meuwly Bravo, Ralf Koberstein University of Basel, Klingelbergstrasse 50/70,CH-4056 Basel, Switzerland Drug Discovery, ActelionPharmaceuticalsLtd., Gewerbestrasse16, 4123 Allschwil, Switzerland
Orexins arehypothalamic peptides that play an importantrole in main- In recent yearsvirtual screening toolsare becomingincreasinglyimportant taining wakefulness in mammals.Permanent deficit in orexinergic function forthe drug discoveryprocess. However,the scoring functions many of is apathophysiological hallmarkofrodent, canine and human narcolepsy. thesemethods useare often found to be lacking in accuracy. Previously a Herewereportthat in rats,somnolencewithout cataplexy is induced by MM-GBSA method to calculate binding freeenergies has been validated usingthe well characterized HIV-1proteaseand 16 known ligands as atest pharmacological blockade of both orexin OX1 andOX 2 receptors. We de- scribe the medicinalchemistry efforts thatled fromthe initiallead structure system [1]. We would like to extend this methodtoimprove poses gener- ( 1 )tothe clinical candidate ACT-078573 ( 2 ). ated fromvirtual screening methods by molecular dynamics simulations and O O useMM-GBSAasamore advanced scoring technique to obtain better rank- O O N N ing of ligands. O N N ON O H H One of the main obstaclesinthe routine application of molecular dynamics O LEAD simulations in large-scalevirtualscreening projectsisthe calculation time 1 DRUG that is required.GRIDcomputing is apossible solution to this problem, but CF3 2 molecularsimulations arenot well adaptedtothe parallelization requiredfor Thespecific challenge in this project was to find acompound, which crosses calculations on aGRID. This workaims to develop amethod forparalleli- theblood-brain-barrier (BBB) in order to interact with theorexinreceptors zation andshow that parallelized molecular dynamics is able to reproduce in the brain. It alsoneeded to be devoid of cytochrome inhibition and to binding freeenergies in acomparable way to classical molecular dynamics exhibit appropriate pharmacokinetic properties. Objective is to improve simulations and can thereforebeapplied to virtual screening projects. next-day performance that is often impaired with other insomniadrugs.The results found during preclinical and clinical investigations open new per- spectives forstudying the role of endogenous orexinsinsleep-wake regula- [1] HB.Thorsteinsdottir, T. Schwede,V.Zoete,M.Meuwly, Proteins. tion. 2006,65, 407 [1]Catherine Brisbare-Roch et al, NatureMedicine 2007, 13,150-155. [2] Ralf Koberstein et al, Chimia 2003, 57,270.
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Ruthenium(II) 6 -AreneImidazoleComplexes: ThePreorganization of theTrisaccharide Core of Sialyl Lewisx ANew Promising ClassofOrganometallic Compounds in Anticancer Is Essential for Binding to E-selectin Therapy Alexander Titz,Beatrice Wagner,Beat Ernst Carsten A. Vock and Paul J. Dyson Institute of MolecularPharmacy,University of Basel Institut desSciences et IngénierieChimiques, Ecole Polytechnique Klingelbergstrasse 50, CH-4056 Basel FédéraledeLausanne (EPFL), CH-1015 Lausanne, Switzerland Theselectins playakeyrole in theinflammatory process. Sincethe physio- Duringthe last decade, ruthenium-based anticancer drugs have becomean logical ligands of theselectinsall containthe tetrasaccharideepitope sialyl important fieldofresearch in organometallic chemistry. Ruthenium(III) Lewis x (sLex ), this epitope served as lead structureinthe search forE- complexeslike NAMI-A[1] or KP1019[2] have shown promising antimeta- selectin antagonists.Ithas been shown that the preorganization of the core static activity andhavesuccessfully completedphase Iclinical trials.Al- in the bioactive conformation [ 1 ] contributessubstantially to the affinity of though imidazole ligands arefrequently used with ruthenium(III) drugs, E-selectin antagonists [ 2 ] . onlyafew examples of ruthenium(II) 6 -arene imidazole complexesare In additiontothe exoanomeric effects, thereare twofactorsthatstabilizethe known, and none of them has been biologically evaluatedsofar. coreconformation of sLe x :(i) by steric compression with sterically demand- ingsubstituents of the GlcN Ac moiety and (ii) by lipophilic interaction be- Therefore, with theintentiontocombine aspectsofbothruthenium(III) and tween thealpha-face of fucosewith thebeta-face of galactose. ruthenium(II) 6 -arene anticancer drugs,our research has focussedonthe synthesis,characterisation and biological evaluation of ruthenium(II) 6 - areneimidazole complexes.[3] Furthermore,the imidazole strategy has been used to attach bioactiveorganicligands to ruthenium(II) 6 -arene fragments in order to obtain newand morepowerfuldrugs. [4] Thepresenta- tion will give asummary of ourresearch in this field.
x [1]J.M.Rademaker-Lakhai, D. van denBongard, D. Pluim, J. H. Beijnen, Stabilizing interactions of the bioactive conformation of sLe J. H. Schellens, Clin. Cancer Res. 2004, 10,37173727. [2]M.A.Jakupec, V. B. Arion, S. Kapitza, E. Reisner, A. Eichinger, M. In order to verifythe above considerations,aseries of E-selectin antagonists Pongratz, B. Marian, N. Graf von Keyserlingk, B. K. Keppler, Int. J. weresynthesized and biologically evaluated. Clin. Pharm. Ther. 2005, 43,595596. [3] C. A. Vock, C. Scolaro,A.D.Phillips, R. Scopelliti, G. Sava,P.J. [ 1 ] Scheffler,L.; Ernst, B. et al. Angew. Chem. Int. Ed. 1995, 34,1841. Dyson, J. Med. Chem. 2006, 49,55525561. Rinnbauer,M.; Ernst, B. et al.Glycobiology 2003, 13,435. [4]C.A.Vock, W. H. Ang, C. Scolaro, A. D. Phillips,L.Lagopoulos,G. [ 2 ] Kolb, H. C.;Ernst,B. Chem. Eur. J. 1997,3,1571. Thoma, G. et al. Sava,L.Juillerat-Jeanneret, P. J. Dyson, J. Med. Chem.,ASAP. Angew. Chem.lnt.Ed. 2001,40 ,1941. MEDICINAL CHEMISTRY431 CHIMIA 2007, 61,No. 7/8
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NVP-AEB071: Oral and Specific InhibitorofTcell Activation forthe Structural and Functional Studiesofthe N-terminal domain Prevention of GraftRejectionand theTreatment of of theY4GPCR Autoimmune Diseases Chao Zou ,Stefan Markovic, Reto Walser,OliverZerbe* Rainer Albert, Marc Bigaud, Nigel Cooke, Sylvain Cottens,Jean-Pierre Evenou, Randall Morris,Charles Pally,RichardSedrani, Walter Schuler, Institute of Organic Chemistry, 8057 Zurich, Switzerland Maurice van Eis, Jürgen Wagner,Gerhard Zenke, Peter von Matt G-protein coupled receptors(GPCRs)comprises 2% of the human genome, ATDA andGlobalDiscovery Chemistry, Novartis Institutesfor BioMedical andalmostone thirdofthe drugs on the markettargetGPCRs.Neuropeptide Research, Postfach, 4002 Basel, Switzerland Y(NPY) receptors(Yreceptors) areimportant in the regulation of blood pressure,memoryretention and food intake[1]. In human organisms func- tional Y1, Y2, Y4 and Y5 subtypes have been identified. While NPY and Immunosuppressants with an improved therapeuticwindow represent ahigh PYY targetall subtypeswith nanomolaraffinities, the pancreatic peptide medicalneed. Thesearch fornovel approaches to blockT-cell activation led (PP) preferentially binds to the Y4 receptor.Wehaveproposed that peptides to NVP-AEB071, aselective and potent inhibitor of classicaland novel pro- from the NPY family associatewith themembrane prior to binding to the tein kinase C(PKC)isoforms with K valuesinthe low nM range. i receptor[2]. Herein, we have structurally characterized theN-terminal ex- H N tracellulardomainofthe Y4 (N-Y4) receptor and determined whether the OO hormones bind to the isolated domain:
N N N H N
N NVP-AEB071
T-cellactivation is effectively blockedasdetermined by inhibition of IL-2 N-Y4 wasproduced both by solid phasepeptide synthesis and recombinant production (IC50 ~5nM).Incontrast,IL-2-dependent Tcell proliferation is not affected. NVP-AEB071 dose-dependently prolongs Brown-Norway techniques in 15N-labeledin E.coli .Wecomparedthe structureofN-Y4in heartgraftsinLewis rats with all animals reaching28days without clinical solution in the presence and absence of phospholidmicelles by NMR. Bind- adverse events at an oral doseof30mg/kg bid. ing affinitiesofpeptidesfrom the NPY family to N-Y4 have been measured by SPR and mutagenesis experiments revealed the interaction sites. This lecturedescribes the medicinal chemistry programthatled to NVP- AEB071 and highlights its effectivenessasanovel immunosuppressant in [1]Grundemar,L., and Bloom, S. R. (eds). Neuropeptide Yand drug de- animalmodels of transplantation andits tolerabilityinaPh Iclinical trial. velopment, 1997,Academic Press. [2]Bader,R., Zerbe, O. ChemBioChem, 2005,6,1520-1534.
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Non-phosphate inhibitorsofIspE, akinaseinthe non-mevalonate TheRole of Sphingosine-1-PhosphateReceptor Modulators in the pathway andapotentialtargetfor antimalarial therapy Prevention of Transplant Rejectionand Autoimmunity
Anna K. H. Hirsch ,S.Lauw, P. Gersbach, W. BerndSchweizer,F.Rohdich, R. Albert, C. Beerli, M. Bigaud, V. Brinkmann, C. Bruns,N.Cooke, N. W. Eisenreich, A. Bacher,F.Diederich Gray, D. Guerini,K.Hinterding, B. Nüsslein-Hildesheim, C. Pally,S.Pan, C. Spanka,MStreiff, F. Zécri Laboratorium fürOrganischeChemie,ETH Zurich,8093 Zurich, Switzerland Novartis Institutesfor BioMedical Research, Autoimmune Disease&Transplantation, CH-4002 Basel, Switzerland Malaria remains the mostimportant and devastating tropical disease known with 300-500 millionclinical cases and around one million deaths ayear. FTY720 is anovel immunomodulator which is highly effective in animal Theemergence of drug and insecticideresistance theneed formedicines models of organtransplantation andautoimmunity.Phase III clinical trials with anovel mode of action has become increasingly important. for de novo kidneytransplantationwererecently discontinued, while Plasmodium parasites,the causative agents of malaria,use the non- FTY720 successfully completed PhaseIIclinical trials forrelapsing- mevalonate pathway forthe biosynthesisofthe common isoprenoid precur- remitting multiple sclerosis and recently entered PhaseIII forthisindica- sors,whichisdistinctfrom thatusedbyhumans.Hence, the enzymesofthis tion. FTY720-phosphate, the activemetabolite generated upon in vivo phos- pathwayare ideal targets in thefight againstthis important infectious dis- phorylation, acts as apotent agoniston4ofthe 5known sphingosine-1- ease[1]. phosphate (S1P)receptors. ThekinaseIspE, at the center of thenon-mevalonate pathway, was chosen as thetargetofastructure-based drug designproject leading to potent com- H O H O F F OH F petitive inhibitors with K i values in the nanomolar range [2]. Thesyntheses H N H N 2 2 O N and biological activities of thesecompounds will be presented. H OH C H O(CH ) C F 8 17 2 3 2 5 S
FTY720 NIBR713 AUY954
NIBR713,showsselectivity overthe S1P3 receptor while retaining its abil- ity to reduce peripheral lymphocyte counts both in rats and monkeys after p.o. application. AUY954,isamonoselective S1P1agonistwith nanomolar potency and good pharmacokinetic properties both in rats and monkeys in- [1]H.Jomaa et al. , Science 1999, 285,1573. ducing aprofound and reversible reduction of lymphocyte countsand pro- [2]A.K.H.Hirsch, S. Lauw, P. Gersbach, W. B. Schweizer,F.Rohdich, longed survival of cardiac allografts in rats.This demonstrates that targeting W. Eisenreich, A. Bacher,F.Diederich, ChemMedChem 2007,DOI: S1P1 is sufficient to achieve immunomodulation in vivo. 10.1002/cmdc.200700014 MEDICINAL CHEMISTRY432 CHIMIA 2007, 61,No. 7/8
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Structure-guided OptimizationofAminobenzoquinolizines Towards Ruthenium-PorphyrinCompounds forPhotodynamicCancer Therapy LowNanomolar DPP-IV Inhibitors Bruno Therrien Markus Böhringer,Holger Fischer,Luca Gobbi, Michael Hennig, Jörg Huwyler, BerndKuhn,Bernd Löffler,ThomasLübbers, Patrizio Institut de Chimie, Université de Neuchâtel,CasePostale 158, CH-2009 Mattei, RobertNarquizian, Jörgen Nielsen, Hans PeterWessel, Pierre Wyss Neuchâtel, Switzerland.
F. Hoffmann-LaRoche Ltd.,PharmaceuticalsDivision, Preclinical Research Porphyrin derivatives areknown to concentrate in cancer cells and they are PRBD,CH-4070 Basel, Switzerland used as photosensitising agents in the photochemotherapy of cancer.Ruthe- nium possesses severalfavourable properties suited to rational anticancer Theserineproteasedipeptidyl peptidaseIV(DPP-IV) is aclinically vali- drug design. It is thought that ruthenium complexes reduce tumour growth dated target forthe treatment of type II diabetes and has received great in- by amechanismofinteraction with DNAalthough non-genomic targets also terestfromthe pharmaceutical industryoverthe last years[1].Concomitant appear to be important. Therefore, we wereinterestedincoordinating arene- with alarge variety of published smallmolecule DPP-IV inhibitorsacon- ruthenium units to porphyrin moiety to combine thephotodynamic action of siderable number of co-crystalstructures have been solved providing asolid porphyrin with the cytotoxicity of arene-rutheniumcomplexes.Aseries of basis forthe understanding of molecularrecognitioninthis enzyme. organo-ruthenium modifiedporphyrin compounds has been prepared and Glu 206 Tyr662 the in vitro tumourcellgrowth inhibition effectsassessed. Glu 205 NH + NH + O 3 3 R Cl R M Cl M R O N N Cl H Cl O MeO MeO N R N N H = O S1 pocket N N H MeO MeO N Cl Cl N N 1 2 M Cl M Cl R M=Ru, Rh ,Ir, Os We describeour multidisciplinaryapproach to optimize the aminobenzo- R quinolizine HTShit 1 to potent DPP-IV inhibitorsofthe general structure 2 They show astrong photodynamic activityonmelanomasafter exposureto (R =aryl, heteroaryl, 2-oxopyrrolidin-1-yl).The focus of this presentation is light. In particular,two of the eight complexeswereonly slightly cytotoxic placed in theanalysis of thecentralmolecular interactions and theirexploi- towards two metastatic cancer cell lines,unlessexposed to light. These tation by structure-based designmethods. complexesofferaconsiderablepotentialinterms of future drug andirradia- tion leveloptimisation [1]. [1]D.Hunziker,M.Hennig, J.-U. Peters, Curr. Top. Med. Chem. 2005, 5 , 1623-1637 [1]B.Therrien, P. Govindaswamy, G. Süss-Fink, W. H. Ang, P. J. Dyson, F. Schmitt, L. Juillerat-Jeanneret, submitted .
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Enzymatic Functionalizationand Radiolabeling of aTumorAffine Structural studies of fragments of Ste2p,aG-proteincoupled receptor Monoclonal Antibody Using Transglutaminase from yeast, in membrane-mimicking environments
1,2 2 2 1,2 Simone Jeger ,Alexander Hohn ,JürgenGrünberg and Roger Schibli A. Neumoin1 ,L.S.Cohen2 ,B.Arshava2 ,J.Becker3 ,F.Naider 2 1 1 Department of Chemistryand Applied Biosciences, ETHZ, 8093 Zurich, and O. Zerbe * Switzerland. 2 Center forRadiopharmaceutical Science ETH-PSI-USZ,PSI, 5232 Villigen, Switzerland 1 Institute of Organic Chemistry,University of Zurich, 2 College of Staten Island, CUNY, 3 University of Knoxville, Tennessee Antibodies (mAb) functionalized with the chelatordeferoxamine (DF) and radiolabeled with 89Zr showedpromising clinical results [1]. However, the Structural studies of G-protein coupled receptorsare often hampered by five-step coupling of DF to the lysine(Lys) side chains of the mAb by problems in expressing, purifying and reconstituting the receptorsaswell as chemical methods is laborious (see Figure, route B). Using the enzymatic activity of bacterialtransglutaminase (BTGase) we in the spectroscopy of theselarge systems.Tocircumvent some of these wereable to link the primary pentyl amino residue of unmodifiedDFto problems we have looked at fragments comprisingthe transmembrane (TM) glutamine(Gln) side chains of the tumoraffinemAb chCE7agl, via forma- segments.Hereinwereportonthe structureand dynamics of alarge seg- tion of isopeptide bonds under physiological conditions in asingle step mentsofSte2p, the G-protein coupled -factor receptorfromyeast[1],us- (route A).The ligand-to-protein ratio wasdeterminedtobebetween 2and 3, ing solution NMRspectroscopy. We investigatedthe 73-residue peptide whereas forthe chemical method the ratio was foundtobe1only. TM7consisting of the thirdextracellular loop, the 7th transmembrane helix Theimmunoconjugate was radiolabeled with 67Ga. Addition of excessDFto [ 67Ga-DF]-chCE7agl showed only slight transchelation of 67Ga, proving the and40residuesfrom the cytosolic C-terminaldomain [2] in stability andspecificity of the radiolabeling. dodecylphosphocholine (DPC)micelles.The structurereveals the presence Theimplementation of the procedurefor the functionalization of chCE7agl of an -helix forresidues 10 to 30, which is perturbed around the internal with other chelating systems suitable forradiolabeling with 67Cu (e.g. Pro24 residue. Spin-label data indicate that the -helix integratesinto DPC CPTA,DOTA),aswellasinvitro andinvivostudiesare in progress. micelles so that residues 22 to 26 arepartially exposed to solution. Moreover,the data reveal asecond site of interaction with the micelle within thecytosolic portion[3].Our present effortsare concentratedonthe structural studies of the 80-residue peptide TM1-TM2consisting of the 19 residuesfrom N-terminaldomain, the 1sttransmembrane helix, the first cytoplasmic loop, the second transmembrane helix and 7residues fromthe firstendoplasmic loop in lyso-palmitoylphosphatidylglycerol(LPPG) mi- celles. [1] N. Nakayama,A.Miyajima,K.Arai, EMBO J. 1985,10, 2643-2648. [2]R.Estephan, J. Englander,B.Arshava, K. Samples, J. Becker,F. Naider, Biochemistry 2005,44, 11795-11810. [1]Verel et al. JNucl Med , 2003, 44,1271-1281. [3]A.Neumoin, B. Arshava, J. Becker,O.Zerbe,F.Naider, Biophys.J. 2007,inpress MEDICINAL CHEMISTRY433 CHIMIA 2007, 61,No. 7/8
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Synthesis, Crystallography and BiologicalEvaluationofMonocationic Strucure baseddiscoveryofpotentselective inhibitors Complexes[Ru( 6 - p -cymene)(Racac)(PTA)][X] of Leishmnia sirtuin
(Racac =DifferentSymmetric 1,3-Diketonates; X=BPh 4 ,BF 4 ) Rameshwar U. Kadam1 ,Joana Tavares2 ,Kiran V. M 1 ,AnabelaCordeiro 2 , Carsten A. Vock, Anna K. Renfrew , Hervé Pittet, Ali Ouaissi3 ,and Nilanjan Roy 1 * Lucienne Juillerat-Jeanneret and Paul J. Dyson Centre of Pharmacoinformatics 1 ,National Institute of Pharmaceutical Edu- cation and Research, S.A.SNagar-160062,India; Faculdade de Farmacia da Institut desSciences et IngénierieChimiques, Ecole Polytechnique 2 3 Fedérale de Lausanne (EPFL), CH-1015 Lausanne Universidade do Porto ,Portugal and "Pathogeniedes Trypanosomatides ", 34394 Montpellier Cedex 5, France University Institute of Pathology, CHUV,Rue de Bugnon 25, CH-1011 Lausanne,Switzerland. In the recent yearsvisceral leishmaniasisisrapidly emerging as an oppor-
6 tunistic infection in HIV patients,inpregnancy andorgan transplant. Glob- Thedevelopmentofnew ruthenium(II) -arene complexesaspotential alizationand consequent travel of peopleacrossthe world has increased the [1,2] anticancer agentshas gainedconsiderableinterestduringthe last years. chances of spreading theinfection. Since theavailabletreatment for RAPTAcomplexeswith PTAligands (PTA =1,3,5-triaza-7-phospha- leishmaniasis poses many problems,researchersare looking fornovel tar- [1] adamantane)haveshown promising antimetastatic activity, and complexes gets in ordertodevelop newdrugs.Inthisquest,wehavebuilt homology [2] with acetylacetone ligands exhibit strong cytotoxic effects. model of LmSir2,anemergingtargetand didcomparativeanalysis of co- factor and substrate binding site of leishmania and human Sir2. Our finding indicates fewsubtle structural deference in NAD binding and catalytic do- main of LmSir2and human Sir2.1 In abid to identifycompounds selective to LmSir2, we have screened 2x10 5 NCIcompounds based on nicotina- mide fingerprintfollowed by docking in boththe active site. Thecom- pounds showed selectivity in docking study is subjected to in-vitro enzy- matic and cell killing assay. We have successfully identified fewcom- In ordertocombine both moieties, we willpresent synthetic andcrystallo- pounds which areselective against LmSir2and cankill axenic amastigotes graphic aspects forthe novel monocationic complexes [Ru( 6 - p -cymene) in culture.Our result indicates thatthis strategy canbeusedfor screening of more selective LmSir2 inhibitors. (Racac)(PTA)][X] (Racac =different symmetric 1,3-diketonates;X=BPh4 , 1400 AD- BF4 ). Results of biological in vitro studieswill be included. -N 1200 1000 NAD+
800 Control
340/460 600 2,5mMNCI 7 at [1]W.H.Ang, P. J. Dyson, Eur. J. Inorg. Chem. 2006,40034018. 400 200
0 [2]A.Habtemariam, M. Melchart, R. Fernandez, S. Parsons,I.D.H. Fluorescence Oswald, A. Parkin, F. P. A. Fabbiani, J. E. Davidson, A. Dawson, R. E. [1]Kadam, R. U.;Kiran,V.M.; Roy, N, Bioorg. Med. Chem. Lett. 2006, Aird,D.I.Jodrell, P. J. Sadler, J. Med. Chem. 2006 , 49,68586868. 16, 6013-8 .
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Nuclear targeted therapyusing 99mTc-intercalatingcomplexes Natural Product-Like Furo[3,4-c ]pyranones as Lead Structure for Novel Anticancer Agents Patricia Antunes ,Eszter Boros, Roger Alberto Cyril A. Fuhrer a ,Stephan Ruetzb ,Alina Nussbaumer a ,Fabian Wengera and Institute of Inorganic Chemistry,University of Zurich, RobertHänera Winterthurerstrasse 190, 8057 Zurich, Switzerland a Department of Chemistry, University of Bern,CH-3012 Bern,Switzerland Beside its usefulnessfor radioimaging the potential application of 99mTc for b Novartis Institutes of Biomedical Research, CH-4002 Basel, Switzerland therapeutic purposes is basedonits radiotoxicity as caused by low energy and high LETAuger electrons.Nevertheless, thetherapeutic potentialof New drugs arerequired to combat drug resistance, forthe improvement in this Auger-emitting radionuclide is critically dependent on the cellular local- the treatment of existing diseases,the treatment of newly identified diseases isation. An intranuclear decayiscrucial to provoke cellular catabolism and the production of saferdrugs by the reduction or removal of adverse through DNA damage. Forthis purpose, the conjugation of DNA targeting side effects. andbinding molecules in theligands designiscrucial.Wehave recently We have shown that natural product-like compounds can improve the drug proved theprinciple that intercalatorscan be used as carriersfor 99mTc into discovery namely the hit/lead identification process.1 In connection with this the nucleus.[1,2] In extending thisprinciple to ourwork, DNA intercalators strategy we recently reported the synthesisofdifferent natural product-like like acridine orange and Hoechstare attached to mono/bidentate ligands in furo[3,4- c ]pyranones. 2 Thesecompounds like 1 ,containing a cis -stilbene ordertotarget nuclear DNA with the corresponding Re/99mTc-complexes. motif,exhibited interesting anticancer properties in different human cancer Theremaining position should then be occupied with acell specific recep- celllines.3 Afteridentification of the cis -stilbene as pharmacophorewenow tor-targeting agent. This [2+1] methodology is used with avariety of investigate how thesubstitution pattern of this motif correlatestothe bio- monodentate ligands,including amodel dipeptide. The in vitro studies of logical activity. Ashort summary of this structure-activity relationships 99m thesenew Re/ Tc-intercalatingagentswill be presented. (SAR)study will be presented.
a) b) N N N R''' R O 4 R' O 1 HN O O H N (+/-) H HN N R'' OH N H N N O O N O Acridine Orange a) andHoechst b) basedligands [1]R.Messer,C.A.Fuhrer,R.Häner, Curr. Opin.Chem. Biol. 2005, 9 , 259-265. [1]P.Haefliger,N.Agorastos,A.Renard, G. Giambonini-Brugnoli, [2]C.A.Fuhrer,R.Messer,R.Häner, Tetrahedron Lett. 2004, 45,4297- C. Marty, and R. Alberto, Bioconjugate Chem. 2005 , 16,582. 4300. [2]N.Agorastos,L.Borsig, A. Renard, P. Antoni, G. Viola, B. Spingler, [3]C.A.Fuhrer,E.Grüter, S. Ruetz,R. Häner, ChemMedChem 2007, 2 , P. Kurz,and R. Alberto, Chem. Eur. J. 2007,000. 441-444. MEDICINAL CHEMISTRY434 CHIMIA 2007, 61,No. 7/8
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Combinatorial Variation of BranchingLengthand Multivalency in a FactorsModulating Time-Dependent DistributionofChlorin Deriva- Large (390'625 Member) Glycopeptide DendrimerLibrary: tivesinPhospholipid Membranes Ligands forFucose-specificLectins MartinaVermathen,Peter Bigler Emma M. V. Johansson ,Tamis Darbre,Jean-LouisReymond* University of Berne,Department of Chemistry andBiochemistry, Freiestrasse 3, 3012 Bern,Switzerland Department of Chemistryand Biochemistry, University of Berne, Freiestrasse 3, 3012 Berne, Switzerland Membranepenetration of porphyrinic drugs is believed to be one of the cru- cial factorsfor theirefficiency in Photodynamic Therapy (PDT)ofdiseased Theantibiotic-resistant pathogenic pseudomonas aeruginosa bacterium tissues,since singlet oxygen, the actual cytotoxic species,unfolds its effect causes lethal respiratorytract infections in cystic fibrosis patients.The fu- mainly in the immediate surrounding of the location whereitisgenerated, cose specific lectin PA-IIL (LecB)mediatestissueattachment andbiofilm [1] i.e. the location of the excited photosensitizer [1]. In this study previous formation and can be inhibited by fucose. We have discovered high- NMR-spectroscopic kinetic studies of chlorin e6 (CE) and mono-L-aspartyl affinity ligands forPA-IILbyscreening combinatorialfucosyl-peptide den- chlorin e6 (MACE) transition across the phospholipid (PL)-bilayer [2]were drimerlibraries.[2] Here we reportastudy of multivalency effects in these [3] extended to further determine the factorswhich modulatethis distribution ligandsusing an innovative combinatorial approach. process. Addition of CE or MACE resultedincharacteristic changesinthe 1 HNMR spectrum of dioleoylphosphatidyl choline(DOPC)vesicles,most (X) (X) (X) n (X)n n n pronounced being asplit of the PL-choline resonances.Atneutral pH CO2 H (X) n (X)n (X)n MACE remained surface attached while CE slowlydistributed acrossthe H C O (X)n + 3 OH bilayer[2].For CE an exponential relationship wasfound between the tran- (X)n OH OH (X) n (X) n sition rate constant and the pH of the surrounding medium, while forMACE (X) (X) 1 (= ) n n reduction of the pH hadonly little effect.Inaddition, the rate constant was (X) n Tripod library (X) (390'536 structures) n found to depend on chlorin concentration. Increase in membranerigidity reduced the transition rate of CE as was derived fromstudies performed bis- to penta-valentglycodendrimers with cholesterol containing DOPC vesicles. In conclusion, the above results demonstrate that membranelocalization anddistribution of the porphyrinic [1]D.Tielker et al., Microbiol. 2005, 151,1313. compound canbeverysensitive to small changesinthe physico-chemical [2] E. Kolomiets, E. M. V. Johansson, O. Renaudet, T. Darbre, propertiesofthe chlorin vesicle system. J.L.Reymond, Org. Lett. 2007, 9 ,1465-1468. [3]E.M.V.Johansson, E. Kolomiets, D. Tielker,K.-M. Bartels, [1]A.Castano, T.N.Demidova, M.R. Hamblin, Photodiagnosis and Pho- F. Rosenau, K.-E.Jäger,T.Darbre, J.-L.Reymond, N. J. Chem. 2007, todynamic Therapy 2004, 1 ,279. DOI:10.1039/b616051b. [2]M. Vermathen, U. Simonis, P. Bigler, J. Porphyrins Phthalocyanines 2006, 10,519.
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AComputational Study on theDimerization of Insulin Studies on theTotal Synthesis of Resorcyclic Lactone LE-783,277 ANew Lead Structure for KinaseInhibition Manuela Koch,Markus Meuwly Tatjana Hofmann,Karl-Heinz Altmann University of Basel, Klingelbergstrasse 80, CH-4056 Basel,Switzerland Institute of Pharmaceutical Sciences,ETH Zurich, In recent years the number of social diseases has steadily increased. Dia- Wolfgang-Pauli-Strasse 10, 8093 Zurich,Switzerland betes mellitus is one of thebiggest impacts on adults of working age and is reaching epidemic proportions in industrial countries.1 , 2 Kinaseshave emerged as important drug targets in cancer andinflammatory Patients suffering from Diabetes mellitus are not able to either produce diseaseand several low-molecular-weight kinaseinhibitorshave now been or to assimilate insulin and have to be treated with insulin shots. Insulin introduced into clinical practice.[1]The natural product L-783,277 ( 1 ) is apeptide hormone whichcontrols the concentration of glucose in the belongs to the family of resorcyclic acid lactones (RALs),which includes compounds such as zearalenone, C292 (LL-Z1640-2),hypothemycin,or blood stream. In its nativeform insulin aggregates immediately into a Radicicol,and whichexhibit adiverserange of biological activities.[2] hexamer under physiological conditions. In the human body only the L-783,277 ( 1 )isapotent inhibitor of the Ser/Thr kinase MEK.[3] No total monomeric form binds to the receptor what causes severe problems in synthesis of 1 has been reported so farand the biological activity of the insulin therapy. Experimentally,itwas found that mutations at theend compound has not been characterized beyond itsability to inhibit afew of the Bchainofthe protein, especially at position B243 have asignifi- selected kinases.The development of an efficient enantioselectivesynthesis cant influence on thereceptor binding potency. 4 of 1 and amoredetailedcharacterizationofits biological effectsare the primarygoals of this research project. Thesynthesis of macrolactone 1 is In this study twoB24-insulin monomer anddimer mutants were investi- based on theconsecutive assembly of thekey fragments A and B ,whose gated using atomistically detailed computer simulations. Moleculardy- synthesis is already implemented. Thepreparationofthe advanced interme- namics simulations forthe nativeand the twomutatedforms showed diate C as well as their ongoing assembly will be described in detail. This differences in flexibilityinparticular at thedimerization interface. As approach will enable the synthesisofanalogsfor SAR studiesand also ameasure for aggregation potency the dimerization energies were calcu- biophysical investigations,inorder to assess its usefulnessasapotential lated andwerecompared to the calculated energy of thenativeform and lead structurefor drug discovery. to the experimentrespectively.
[1] World Health Org. http://www.who.int/diabetes/facts/en.2006 [2] WicoxG., Clin. Biochem. Rev , 2005, 26,19. [3] Hua Q. X., Shoelson S. E.,InouyeK., Weiss M., Proc.Natl. Acad. Sci., 1993, 90,582. [4] DeFelippis M.R., Chance R. E., Frank B. H., Critical Reiews [1]Krause, D. S. and Van Etten, R. H. N. Engl.J.Med. 2005,353, 172-187. in TherapeuticalDrug Carrier Systems, 2001, 18,201. [2]Winssinger,N.and Barluenga, S. Chem. Commun. 2007, 1 ,22-36. [3] Zhao,A.; Lee, S. H.;Mojena,M.; Jenkins,R.G.; Patrick, D. R.;Huber, H. E.; Goetz, M. A.;Hensens,O.D.; Zink,D.L.; Vilella, D.;Dombrowski, A. W.;Lingham, R. B.;Huang, L. J. Antibiot. 1999,52 (12),1086-1094 MEDICINAL CHEMISTRY435 CHIMIA 2007, 61,No. 7/8
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Interactions of abacterial lipopolysaccharide with antibacterial Novel BisubstrateInhibitors of Catechol- O -Methyltransferase peptides (COMT): Investigation of theRiboseStructural Unit