Targeting glioblastoma stem-like cells with custom-designed viral vectors

Abstract GlioblastomaGBMis the most lethal form of adult brain cancers with a median survival of andltmonths despite aggressive standard chemoradiationGBM are formed by GBM stem like cellsGSCsa major contributor to tumor recurrence and a natural focus for therapeutic developmentThere are two main reasons responsible for treatment failurehigh intraand inter tumor cellular and molecular heterogeneity with multiple subclones possessing distinct genetic determinantsGSCs exhibit multiple redundant signaling pathways requiring simultaneous targeting of overlapping pathwaysWe have invented and biologically validated a novel tandem computational platformGeneRep nSCORE that integrates large scale gene expression profiles with genomic changes to identify common founding alterations or master regulators of GSCs that span a large numberif not allGSC subclones within and across GBM tumorsWe discovered such a core set of four common master regulators in GCSs that are outstanding targets for clinical developmentExpression of these four factors was sufficient to reprogram normal astrocytes to GSCswhereas their depletion profoundly abrogated GSCsand thus tumor development in vivoin all eight lines of patient derived GSCs of varied genetic and molecular backgrounds examined to dateThe goal of this application is to develop a customized set of Adeno associated virusAAVbased genetic tools to target the whole spectrum of GSCsPhase Ifor the purpose of delivering targeting constructs to deplete the four common master regulators responsible for malignant transformation and proliferation in GSCsPhase IIThe specific objectives of this proposal areiusing directed evolution and available combinatorial AAV capsid libraryand for the first timeintroducing a dynamic mode of administration of a library reagent over the time course of tumor progressionto greatly increase the probability of identifying novel AAV variants specifically targeting slowand fast cycling GSCs in patient derived xenograft modelsPDXPhase IiiTo design and validate a panel of AAV vectors that express shRNAs targeting core master regulators of GSCs to identify leads for preclinical testingiiiTo optimize modes of viral deliverypharmacokinetics and pharmacodynamics parametersand safety and toxicity in normal and PDX treated with lead targeting AAV cassettesandivBased on these resultstools and basic DMPK data createdto conduct preclinical efficacy studies in PDX treated with lead targeting AAV cassettes either alone or in combination with standard chemoradiotherapyPhase IIto prepare for an investigative new drug application for clinical testing in patients with GBMand for commercial development of this novel technology Narrative GlioblastomaGBMis the most lethal form of adult human brain cancersThe goal of this proposal is to develop a customized set of viral vectors specifically targeting GBM stem like cellsThese novel viral vectors will express targeting constructs to deplete common master regulators responsible for malignant transformation and proliferation of these GBM stem cells such as tumor control and survival can be improved