Oneofthegreatestchallengesincancerbiologyishowtoovercomeissuesoftumorheterogeneityanda dynamicmicroenvironmenttoselecteffectivetherapeutictreatments,reducetherapyresistance,andproduce betterpatientoutcomes.Whilegeneticsequencingasstandardofcareforsolidtumorshasexpandedthe therapeutictoolbox,themolecularmechanismsunderlyingtumorheterogeneity,metastasis,anddrug resistanceremainpoorlyunderstood.Forexample,failuresoftargetedtherapieslikePI3kinaseinhibitors highlighttheneedforbetterunderstandingofhowgeneticandphenotypicheterogeneityworkinconcertwith microenvironmentpressurestoenablecancercellsurvival,metastasis,andevolution.Althoughlesswell studiedintermsofheterogeneity,increasedintracellularpH(pHi)isafeatureofmostcancersandenablesa hostofcancerphenotypes,includingincreasedcellproliferation,metastasis,evasionfromapoptosis, migration,anddrugresistance.WhiletheconstitutivelyhigherpHiofcancerhasbeenshowntoenablethese behaviorsonapopulationlevelinvariousmodels,littleisknownabouthowsingle-cellspatiotemporalpHi dynamicsorpHheterogeneitymightinfluenceordrivesingle-cellcancerphenotypes.Here,Iwillusean innovativeoptogenetictooltospatiotemporallymanipulatepHiinlivingcellsandelucidatetheroleofpHi dynamicsininitiatingorsupportingsingle-cellcancerbehaviors.IhypothesizethatincreasedpHiisacritical indicatorofcancercellfunctionanddirectlyrelevanttopromotingsingle-cellinvasionanddrugresistance. Furthermore,IpredictthatpHiheterogeneitycorrelateswithothermorecrypticmarkersofheterogeneity includingmetabolicchanges,stemcellmarkers,andepithelialandmesenchymalmarkers.Inthiswork,I proposetherigorousinvestigationoftherolesofpHiinsupportingcancercellbehaviorsthroughtwo complementaryapproaches.First,IwilluseanoptogenetictooltoincreasepHiinsinglecellstodetermine whetherincreasedpHiissufficienttodrivesingle-cellinvasionanddrugresistancein2Dand3Dcancer models.Second,IwillobtainpHiheterogeneitymapsof3DcancermodelstodetermineifmonitoringpHi increasescanbepredictiveofindividualcellsthatarelikelytomigrate,invade,oracquiredrugresistance.The abilitytodynamicallymeasurepHiinlivingcellsmakespHianattractivebiomarkerforaggressivetumor subpopulations.CompletionofthesestudieswilltransformourunderstandingofhowpHdynamicssupportand promotecancerprogressionwhilerevealingnewroutesformonitoringpHiasadiagnosticorprognostictoolor foridentifyingappropriatetherapeuticinterventions.
Improvementofcancerpatientoutcomesrequiresearlierdetection,bettertargetedtherapeutics,andreduction ofrecurrence.WewillstudyhowtheincreasedintracellularpHofcancerpromotescancercellmigrationand drugresistanceatthesingle-celllevel.WewillalsodeterminewhetherpHiheterogeneitycanreveal informationaboutthelikelihoodofasinglecancercelltometastasizeorsurvivedrugtreatment.
