title: Optical bioluminescence and positron emission tomography imaging of a novel fusion reporter gene in tumor xenografts of living mice.
abstract: Noninvasive imaging of reporter gene expression using various imaging modalitiesis playing an increasingly important role in defining molecular events in the field of cancer biology, cell biology, and gene therapy. In this study, a novel reporter vector was constructed encoding a fusion protein comprised of a mutant herpes simplex virus type 1 thymidine kinase (HSV1-sr39tk) (tk), a positron emission tomography (PET) reporter gene, and renilla luciferase (rl), a bioluminescence optical reporter gene joined by a 20 amino acid long spacer sequence. We validated the activity of the two enzymes encoded by the fusion protein (tk(20)rl) in cell culture. Then, tumors stably expressing the tk(20)rl fusion gene were imaged both by microPET and optically using a cooled charge coupled device camera in xenograft-bearing living mice. Using a single fusion reporter (PET/optical) gene should accelerate the validation of reporter gene approaches developed in cell culture for translation into preclinical and clinical models.
authors.affiliation: Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, David Gefen School of Medicine, University of California, Los Angeles, California 90095, USA.
authors.forename: Pritha
authors.initials: P
authors.lastname: Ray
authors.forename: Anna M
authors.initials: AM
authors.lastname: Wu
authors.forename: Sanjiv S
authors.initials: SS
authors.lastname: Gambhir
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D003063:Cnidaria / Q000201:enzymology; D015870:Gene Expression; D017930:Genes, Reporter; D005910:Glioma / Q000000981:diagnostic imaging / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008156:Luciferases / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D008163:Luminescent Measurements; D051379:Mice; D008969:Molecular Sequence Data; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging* / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000000981:diagnostic imaging / Q000378:metabolism / Q000502:physiology; D055095:Optics and Photonics; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D013937:Thymidine Kinase / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D014055:Tomography, Emission-Computed / Q000379:methods; D014162:Transfection; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured
chemical_list: D011993:Recombinant Fusion Proteins; D008156:Luciferases; D013937:Thymidine Kinase