RecombinantTAT–geloninfusiontoxin:Synthesisandcharacterizationofheparin/protamine-regulatedcelltransductionMeongCheolShin,1,2*JingwenZhao,3*JianZhang,4YongzhuoHuang,5HuiningHe,1MeiWang,6KyoungAhMin,2VictorC.Yang1,21TianjinKeyLaboratoryonTechnologiesEnablingDevelopmentofClinicalTherapeuticsandDiagnosis,SchoolofPharmacy,TianjinMedicalUniversity,Tianjin300070,China2DepartmentofPharmaceuticalSciences,CollegeofPharmacy,UniversityofMichigan,428ChurchSt.,AnnArbor,Michigan481093DepartmentofMolecularandCellularPharmacology,SchoolofPharmaceuticalScienceandTechnology,TianjinUniversity,Tianjin300072,China4BiomedicalPolymersLaboratory,andJiangsuKeyLaboratoryofAdvancedFunctionalPolymerDesignandApplication,DepartmentofPolymerScienceandEngineering,CollegeofChemistry,ChemicalEngineeringandMaterialsScience,SoochowUniversity,Suzhou215123,China5ShanghaiInstituteofMateriaMedica,ChineseAcademyofSciences,501Hai-keRd,Shanghai201203,China6CollegeofPharmacy,XinjiangMedicalUniversity,393XinyiRoad,Urumqi830011,ChinaReceived9March2014;accepted31March2014Publishedonline00Month2014inWileyOnlineLibrary(wileyonlinelibrary.com).DOI:10.1002/jbm.a.35188Abstract:Proteintoxins,suchasgelonin,arehighlydesirableanti-cancerdrugcandidatesduetotheirunparalleledpotencyandrepetitivereactionmechanismininhibitingproteintrans-lation.However,foritspotentialapplicationincancerther-apy,thereremainsthecellmembranebarrierthatallowspermeationofonlysmallmolecules,whichmustbeover-come.Toaddressthischallenge,weconjugatedgeloninwithaproteintransductiondomain(PTD),theTATpeptide,viageneticrecombination.ThechimericTAT–geloninfusionpro-tein(TAT-Gel)retainedequipotentN-glycosidaseactivityyetdisplayedgreatercelluptakethanunmodifiedrecombinantgelonin(rGel),therebyyieldingasignificantlyaugmentedcytotoxicactivity.Remarkably,TAT-Geldisplayedupto177-foldlowerIC50(avg.54.3nM)thanrGel(avg.IC50:3640nM)intestedcelllines.Thisenhancedcytotoxicity,however,alsoraisedpotentialtoxicityconcernsduetothenon-selectivityofPTDinitsmediatedcelltr...
