Mass Spectrometric Bead-Imaging of Off-Target Drug Interactions

DESCRIPTIONprovided by applicantA fundamental challenge in the drug discovery process is to develop drugs with high efficacy and minimal sideeffectsAs an initial step this depends on identifying lead compounds which interact with high affinity and regulate the activity of specific biological drug targets such as a protein involved in a disease pathwayHowevera second equally important step is to verify that these leads do not interact and interfere with the functioning of the vast number of other proteins which comprise the human proteomeA variety of effective methods exist to perform label free high throughput screeningHTSof compound libraries against single drug targetsHoweverthe ability to perform HTS on compound librariesor even a small set of lead compoundsagainst a large library of protein targets has not yet emergedSuch high throughput multidimensional drug screeningHT MDDSwould have a significant impact of the pharmaceutical and healthcare industryMost importantlyit would facilitate proteome wide detection of off target drug protein interactionsSuch interactions often cause serious adverse drug reactionsSADRsresponsible for the overdeaths per year in the U Sexceeding the number of annual deaths due to cancerIn additionHT MDDS would provide a powerful method to discover new targets for existing FDA approved drugs by identifying off target interactions as well as to elucidate the molecular basis of side effects fro on label useIn order to meet this challengeAmberGen has explored during Phase I the use of its proprietary Bead GPS tmtechnology as a means to perform HT MDDS during lead optimizationBead GPS tmis based on MALDI mass spectrometric imagingMALDI MSIof high density random bead arrayswhere each bead in the array carries a unique protein and corresponding photocleavable mass tag for codingPC mass tagBinding of specific compounds to a specific protein is detected by measuring simultaneously the mass of the binders and the photoreleased PC mass tag sresiding on each beadOur initial results demonstrate the feasibility of using BeadGPSTM to screen a drug compound library against thousands of proteins in order to rapidly identify both onand off target interactions on a global proteome wide basisProgress during Phase I includediDevelopment of new photocleavable linkers for facile attachment of mass tags to beadsiiDemonstration of high capacity coding of protein bead libraries with single and double PC mass tagsiiiConstruction of a modelmember PC mass tag coded kinase libraryivScreening the kinase bead library with two known kinase inhibitors demonstratingspecificity and sensitivityDuring Phase IIwe will further optimize Bead GPS tmfor HT MDDS with the goal of establishing it as a standard tool for pre clinical lead optimizationFor this purposewe will construct amember PC mass tagged kinase protein bead libraryThis library will be screened by Bead GPS tmagainst compounds from a modelmember kinase inhibitor libraryOn target and off target interactions from positive hits detected by Bead GPS tmwill be further characterized for binding affinity and inhibitor activity using homogenous kinase assaysas well as by synchronization of fluorescent FRET and MALDI MS images of the random bead arrayImprovements in several aspects of the Bead GPS tmprocess including advanced MALDI MSI instrumentation and software will allowtofold improvements in sensitivity and scan speedIn order to accelerate the development and commercialization of Bead GPS tmAmberGen will work closely with DrCathy CostelloDirectorCenter for Biomedical Mass Spectrometry at the Boston University Medical School and a leading expert in the field of MALDI and its biomedical applicationsDrMarvin Vestalpioneer in MSMALDI instrumentation development and President of SimulTOF SystemsDrMichael Paviaa leader in the pharmaceutical industry and ex CTO of Millennium PharmaceuticalsDrYiwu Heformer Global Head and Senior Director of GlaxoSmithKline and currently Senior Program Officer at the Bill and Melinda Gates Foundation and DrGheorghe DorosAssociate Professor of Biostatistics at the Boston University School of Public HealthAmberGen will also explore the use of improved MALDI MSI instrumentation in collaboration with SimulTOF Systems and Bruker Daltonics