Highly Multiplexed Nanoscale Mass Spectrometric Imaging of Cancer Tissues

SUMMARY ABSTRACT Mass spectrometryMShas played a leading role in the past three decades in the field of proteomicsA combination of innovative MS based techniques has provided powerful tools for proteomic discovery including the ability to identify protein biomarkers in a complex samplequantify changes in protein expression under different conditions including those related to diseaseand characterize protein protein interactions which play a key role in complex cellular pathwaysA second important advance in MS has been the introduction of mass spectrometric imagingMSIwhich extends MS to the spatial dimensionallowing mapping of the distribution of biomolecules including proteinsnucleic acidsmetabolites and even small drug compounds in complex tissuesThe goal of this Phase I project is to enable MSI to perform highly multiplexednanoscale imaging of targeted biomolecules in biospecimensSuch a capability would provide a major tool for systems biologywhich requires detailed knowledge of the structure and structural changes of complex tissues at the molecularsubcellular and cellular levelsIt would also provide critical new information for cancer research and for therapeuticsdiagnostics and monitoring of cancer patients where targeted biomolecules in fresh frozenFFor formalin fixed paraffin embeddedFFPEthin sections of cancer tissue are imagedHoweverseveral difficult challenges remain before routinehighly multiplexed nanoscale MALDI MSI of biospecimens is possible includingideveloping highly sensitive and selective MSIcompatible multiplex mass tag probes for hundreds of biomolecules including proteins and miRNAs and iideveloping methods to obtain nanoscale resolution with MSIIn order to solve these problemswe will explore the use of our newly developed class of improved photocleavable mass tagsiPC MTsduring Phase IInitial studies show that iPC MTs have superior properties such as higher sensitivity compared to earlier developed mass tags and can facilitate simultaneous identification of hundreds of targeted biomolecules in standard FF and FFPE tissue slicesIn contrastconventional immunofluorescent antibodies and fluorescently labeled DNA RNA hybridization probes used with light microscopy can only detect a few target biomolecules simultaneouslyIn additioniPC MTs can incorporatepolymer tetheringgroups making them compatible with the newly developed method of expansion microscopyExMwhich offers the potential to obtain nanometer spatial resolution using MSIThis approach involves the physical isotropic swelling of biospecimens such as FFPE thin sections by embedding into them hydrogel polymersThe application of iPC MTs can thus enable multiplexed nanoscale MSI imagingThis work will be facilitated by our collaboration with leading experts in the MALDI MSI and ExM fields including DrsCathy CostelloBUWilliam Fairfield Warren Distinguished ProfessorDirector of BU Center for Biomedical Mass SpectrometryEd BoydenMITYEva Tan Professor of Neurotechnologyand Jason AmsdenDuke UniversityAssistant Research ProfessorNanomaterials and Thin Films Lab at the Pratt School of EngineeringNARRATIVE Mass spectrometric imagingMSIextends the power of mass spectrometry to the spatial dimensionallowing mapping of the distribution of biomolecules including proteinsnucleic acidsmetabolites and even small drug compounds in complex tissuesThe goal of this Phase I project is to enable MSI to perform highly multiplexednanoscale imaging of biospecimens including cancer tissuesThis will be accomplished through the utilization of novel photocleavable mass tags developed by us which possess improved imaging and molecular selectivity characteristics as well as compatibility with the new method of expansion microscopyThis new capability will provide critical information for cancer researchers and for therapeuticsdiagnostics and monitoring of cancer patients