Highly Multiplexed Nanoscale Mass Spectrometric Imaging of Cancer Tissues

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Molecular & Cellular Analysis Technologies
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Not Applicable
SUMMARY/ABSTRACTMass spectrometry (MS) has played a leading role in the past three decades in the field of proteomics. A combinationof innovative MS-based techniques has provided powerful tools for proteomic discovery including the ability toidentify protein biomarkers in a complex sample, quantify changes in protein expression under different conditionsincluding those related to disease, and characterize protein-protein interactions which play a key role in complexcellular pathways. A second important advance in MS has been the introduction of mass spectrometric imaging(MSI) which extends MS to the spatial dimension, allowing mapping of the distribution of biomolecules includingproteins, nucleic acids, metabolites and even small drug compounds in complex tissues. The goal of this Phase Iproject is to enable MSI to perform highly multiplexed, nanoscale imaging of targeted biomolecules inbiospecimens. Such a capability would provide a major tool for systems biology, which requires detailed knowledgeof the structure and structural changes of complex tissues at the molecular, subcellular and cellular levels. It wouldalso provide critical new information for cancer research and for therapeutics, diagnostics and monitoring of cancerpatients where targeted biomolecules in fresh frozen (FF) or formalin fixed paraffin embedded (FFPE) thin sectionsof cancer tissue are imaged. However, several difficult challenges remain before routine, highly multiplexednanoscale MALDI-MSI of biospecimens is possible including: i) developing highly sensitive and selective MSI-compatible multiplex mass-tag probes for hundreds of biomolecules including proteins and miRNAs and ii)developing methods to obtain nanoscale resolution with MSI. In order to solve these problems, we will explore theuse of our newly developed class of improved photocleavable mass-tags (iPC-MTs) during Phase I. Initial studiesshow that iPC-MTs have superior properties such as higher sensitivity compared to earlier developed mass-tagsand can facilitate simultaneous identification of hundreds of targeted biomolecules in standard FF and FFPE tissueslices. In contrast, conventional immunofluorescent antibodies and fluorescently labeled DNA/RNA hybridizationprobes used with light microscopy can only detect a few target biomolecules simultaneously. In addition, iPC-MTscan incorporate ?polymer tethering? groups making them compatible with the newly developed method ofexpansion microscopy (ExM) which offers the potential to obtain nanometer spatial resolution using MSI. Thisapproach involves the physical isotropic swelling of biospecimens such as FFPE thin sections by embedding intothem hydrogel polymers. The application of iPC-MTs can thus enable multiplexed nanoscale MSI imaging. Thiswork will be facilitated by our collaboration with leading experts in the MALDI-MSI and ExM fields including Drs.Cathy Costello (BU, William Fairfield Warren Distinguished Professor, Director of BU Center for Biomedical MassSpectrometry), Ed Boyden (MIT, Y. Eva Tan Professor of Neurotechnology) and Jason Amsden (Duke University,Assistant Research Professor, Nanomaterials and Thin Films Lab at the Pratt School of Engineering).