title: Optical imaging of targeted β-galactosidase in brain tumors to detect EGFR levels.
abstract: A current limitation in molecular imaging is that it often requires genetic manipulation of cancer cells for noninvasive imaging. Other methods to detect tumor cells in vivo using exogenously delivered and functionally active reporters, such as β-gal, are required. We report the development of a platform system for linking β-gal to any number of different ligands or antibodies for in vivo targeting to tissue or cells, without the requirement for genetic engineering of the target cells prior to imaging. Our studies demonstrate significant uptake in vitro and in vivo of an EGFR-targeted β-gal complex. We were then able to image orthotopic brain tumor accumulation and localization of the targeted enzyme when a fluorophore was added to the complex, as well as validate the internalization of the intravenously administered β-gal reporter complex ex vivo. After fluorescence imaging localized the β-gal complexes to the brain tumor, we topically applied a bioluminescent β-gal substrate to serial sections of the brain to evaluate the delivery and integrity of the enzyme. Finally, robust bioluminescence of the EGFR-targeted β-gal complex was captured within the tumor during noninvasive in vivo imaging.
authors.affiliation: †Department of Radiology and Radiological Sciences, ‡Center of Biomedical Imaging, and §Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina 29425, United States.|∥Department of Biomedical Engineering, ⊥Case Center for Imaging Research, and #The NFCR Center for Molecular Imaging, Case Western Reserve University, Cleveland, Ohio 44106, United States.
authors.forename: Ann-Marie
authors.initials: AM
authors.lastname: Broome
authors.affiliation: †Department of Radiology and Radiological Sciences, ‡Center of Biomedical Imaging, and §Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina 29425, United States.|∥Department of Biomedical Engineering, ⊥Case Center for Imaging Research, and #The NFCR Center for Molecular Imaging, Case Western Reserve University, Cleveland, Ohio 44106, United States.
authors.forename: Gopal
authors.initials: G
authors.lastname: Ramamurthy
authors.affiliation: †Department of Radiology and Radiological Sciences, ‡Center of Biomedical Imaging, and §Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina 29425, United States.|∥Department of Biomedical Engineering, ⊥Case Center for Imaging Research, and #The NFCR Center for Molecular Imaging, Case Western Reserve University, Cleveland, Ohio 44106, United States.
authors.forename: Kari
authors.initials: K
authors.lastname: Lavik
authors.affiliation: †Department of Radiology and Radiological Sciences, ‡Center of Biomedical Imaging, and §Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina 29425, United States.|∥Department of Biomedical Engineering, ⊥Case Center for Imaging Research, and #The NFCR Center for Molecular Imaging, Case Western Reserve University, Cleveland, Ohio 44106, United States.
authors.forename: Alexander
authors.initials: A
authors.lastname: Liggett
authors.affiliation: †Department of Radiology and Radiological Sciences, ‡Center of Biomedical Imaging, and §Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina 29425, United States.|∥Department of Biomedical Engineering, ⊥Case Center for Imaging Research, and #The NFCR Center for Molecular Imaging, Case Western Reserve University, Cleveland, Ohio 44106, United States.
authors.forename: Ian
authors.initials: I
authors.lastname: Kinstlinger
authors.affiliation: †Department of Radiology and Radiological Sciences, ‡Center of Biomedical Imaging, and §Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina 29425, United States.|∥Department of Biomedical Engineering, ⊥Case Center for Imaging Research, and #The NFCR Center for Molecular Imaging, Case Western Reserve University, Cleveland, Ohio 44106, United States.
authors.forename: James
authors.initials: J
authors.lastname: Basilion
mesh_terms: D000818:Animals; D001710:Biotin / Q000737:chemistry / Q000378:metabolism; D019921:Biotinylation; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D045744:Cell Line, Tumor; D004815:Epidermal Growth Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D066246:ErbB Receptors / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D017930:Genes, Reporter; D006639:Histidine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D057054:Molecular Imaging / Q000379:methods*; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism; D009368:Neoplasm Transplantation; D009842:Oligopeptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D061848:Optical Imaging / Q000379:methods*; D013238:Stereotaxic Techniques; D019809:Streptavidin / Q000737:chemistry / Q000378:metabolism; D001616:beta-Galactosidase / Q000235:genetics* / Q000378:metabolism
chemical_list: C471213:His-His-His-His-His-His; D009363:Neoplasm Proteins; D009842:Oligopeptides; D006639:Histidine; D004815:Epidermal Growth Factor; D001710:Biotin; D019809:Streptavidin; C512478:EGFR protein, human; D066246:ErbB Receptors; D001616:beta-Galactosidase