基因毒性杂质之结构警示(欧洲)

EUR23844EN-2009DevelopmentofstructuralalertsfortheinvivomicronucleusassayinrodentsRomualdoBenignia,CeciliaBossaa,OlgaTcheremenskaiaaandAndrewWorthbaIstitutoSuperiorediSanita’,EnvironmentandHealthDepartment,Rome,ItalybInstituteforHealth&ConsumerProtection,EuropeanCommission-JointResearchCentre,Ispra,ItalyThemissionoftheIHCPistoprovidescientificsupporttothedevelopmentandimplementationofEUpoliciesrelatedtohealthandconsumerprotection.TheIHCPcarriesoutresearchtoimprovetheunderstandingofpotentialhealthrisksposedbychemical,physicalandbiologicalagentsfromvarioussourcestowhichconsumersareexposed.EuropeanCommissionJointResearchCentreInstituteforHealthandConsumerProtectionContactinformationAddress:TP582E-mail:[e-mail].:[phone]Fax:[phone]://ec.europa.eu/dgs/jrc/LegalNoticeNeithertheEuropeanCommissionnoranypersonactingonbehalfoftheCommissionisresponsiblefortheusewhichmightbemadeofthispublication.AgreatdealofadditionalinformationontheEuropeanUnionisavailableontheInternet.ItcanbeaccessedthroughtheEuropaserver:OfficeforOfficialPublicationsoftheEuropeanCommunities©EuropeanCommunities,2009ReproductionisauthorisedprovidedthesourceisacknowledgedPrintedinItalyABSTRACTInvivomutagenicityandcarcinogenicitystudiesareposingahighdemandfortest-relatedresources.Amongthesestudies,themicronucleustestinrodentsisthemostwidelyused,asfollowuptopositiveinvitromutagenicityresults.Arecentsurveyofthe(Q)SARmodelsformutagenicityandcarcinogenicityhasindicatedthatno(Q)SARmodelsforinvivomicronucleusareavailableinthepublicdomain.Therefore,thedevelopmentandextensiveuseofestimationtechniquessuchas(Q)SARs,read-acrossandgroupingofchemicals,promisestohaveahugeanimalsavingpotentialforthisendpoint.Inthisreport,wedescribetheidentificationofstructuralalertsfortheinvivomicronucleusassay,andprovidethelistofunderlyingchemicalstructures.Thesestructuralalertsprovideacoarse-grainfilterforthepreliminaryscreeningofpotentialinvivomutagens.LISTOFABBREVIATIONSEPAEnvironmentalProtectionAgencyEUEuropeanUnionFDAFoodandDrugAdministrationHOMOHighestOccupiedMolecularOrbitalISSIstitutoSuperiorediSanita’JRCJointResearchCentreLUMOLowestUnccupiedMolecularOrbitalOECDOrganisationforEconomicCooperationandDevelopment(Q)SAR(Quantitative)Structure-ActivityRelationshipREACHRegistrationEvaluationandAuthorisationofCHemicalsROCReceiverOperatingCurveSAStructuralAlertSA_BBBenigni-Bossastructuralalertsformutagnicity/carcinogenicityinToxtreeSA_MicStructuralalertsrefersfortheinvivomicronucleusassayinToxtreeSA_ProtStructuralalertsforproteinbindingintheOECDQSARToolboxCONTENTS1.Introduction....................................................................................................62.Structuralalerts..............................................................................................83.Developmentofstructuralalertsfortheinvivomicronucleusassay..............104.Finalconsiderations......................................................................................205.References....................................................................................................21Appendix1..............................................................................................................2361.IntroductionMutagenicitytestingisanimportantpartoftheregulatoryhazardassessmentofchemicals.Itisundertakenfortwomainreasons:a)todetectchemicalsthatmightcausegeneticdamageingermcells,andthusincreasetheburdenofheritable(genetic)diseaseinthehumanpopulation;andb)todetectchemicalsthatmightbecarcinogenic(basedontheassumptionthatmutagenesis,forexampleinsomaticcells,isakeyeventintheprocessofcarcinogenesis).Sincenomethodisablealonetodetectallpossiblegenotoxicevents,awidearrayoftestsystemshasbeendevelopedandacceptedinternationallyinregulatoryschemes.Mostoften,thesemethodsareusedwithina2-tieredintegratedtestingapproach:Tier1includesinvivoassays,andTier2includesinvivoassays.Asamatteroffact,mutagenicitytestingwasthefirsttoxicityendpointforwhichinvivoassayswereacceptedforregulatorytesting,some25yearsago.Thelatterusuallycomprisebacterialmutagenicityandcytogeneticstests,althoughgenemutationtestinginculturedmammaliancellsissometimesalsoundertaken.Tier2ofthetestingstrategyinvolvestheuseofshort-terminvivostudies(usuallyabone-marrowcytogeneticsassay)toassesswhetheranypotentialforgenotoxicitydetectedattheTier1invivostageisactuallyexpressedinthewholeanimal.Thus,negativeresultsinvivoareusuallyconsideredsufficienttoindicatelackofmutagenicity,whereasapositiveresultisnotconsideredsufficienttoindicatethatthechemicalrepresentsamutagenichazard(i.e.itcouldbeafalsepositive).TheaboveapproachtogenotoxicitytestinghasbeenadoptedthroughouttheEU1,andhasbeenrecommendedinternationallyaspartofthestrategyforpredictingandquantifyingmutagenicandcarcinogenichazard(Ashbyetal.,1996;Combesetal.,2007;KirklandandSpeit,2008;Lilienblumetal.,2008).1