Leukemiahttps://doi.org/10.1038/s41375-018-0178-xARTICLELymphomaEpstein−Barrvirus-encodedEBNA2altersimmunecheckpointPD-L1expressionbydownregulatingmiR-34ainB-celllymphomasEleniAnastasiadou1●DinaStroopinsky2●StellaAlimperti3●AlanLJiao1●AthaliaRPyzer2●ClaudiaCippitelli4●GiuseppinaPepe4●MartinaSevera5●JacalynRosenblatt2●MarilenaPEtna5●SimoneRieger6●BettinaKempkes6●ElianaMCoccia5●ShannanJHoSui7●ChristopherSChen3●StefaniaUccini4●DavidAvigan2●AlbertoFaggioni8●PankajTrivedi8●FrankJSlack1Received:28June2017/Revised:27April2018/Accepted:11May2018©TheAuthor(s)2018.ThisarticleispublishedwithopenaccessAbstractCancercellssubverthostimmunesurveillancebyalteringimmunecheckpoint(IC)proteins.SomeEpstein−Barrvirus(EBV)-associatedtumorshavehigherProgrammedCellDeathLigand,PD-L1expression.However,itisnotknownhowEBValtersICsinthecontextofitspreferredhost,theBlymphocyteandinderivedlymphomas.Here,wefoundthatlatencyIII-expressingBurkittlymphoma(BL),diffuselargeB-celllymphomas(DLBCL)ortheirEBNA2-transfectedderivativesexpresshighPD-L1.InaDLBCLmodel,EBNA2butnotLMP1issufficienttoinducePD-L1.LatencyIII-expressingDLBCLbiopsiesshowedhighlevelsofPD-L1.ThePD-L1targetingoncosuppressormicroRNAmiR-34awasdownregulatedinEBNA2-transfectedlymphomacells.WeidentifiedearlyB-cellfactor1(EBF1)asarepressorofmiR-34atranscription.ShorthairpinRNA(shRNA)-mediatedknockdownofEBF1wassufficienttoinducemiR-34atranscription,whichinturnreducedPD-L1.MiR-34areconstitutioninEBNA2-transfectedDLBCLreducedPD-L1expressionandincreaseditsimmunogenicityinmixedlymphocytereactions(MLR)andinthree-dimensionalbiomimeticmicrofluidicchips.GiventheimportanceofPD-L1inhibitioninimmunotherapyandmiR-34adysregulationincancers,ourfindingsmayhaveimportantimplicationsforcombinatorialimmunotherapy,whichincludeICinhibitingantibodiesandmiR-34a,forEBV-associatedcancers.IntroductionAmongnon-Hodgkinlymphoma(NHL),morethan95%ofendemicBLsareassociatedwithEpstein−Barrvirus(EBV).DiffuselargeB-celllymphomas(DLBCLs)con-stituteabout30%o...
