title: PET imaging of tenascin-C with a radiolabeled single-stranded DNA aptamer.
abstract: Tenascin-C is an extracellular matrix glycoprotein that is expressed by injured tissues and by various cancers. Recent publications showed that tenascin-C expression by cancer lesions predicts tumor growth, metastasis, and angiogenesis, suggesting tenascin-C as a potential therapeutic target. Currently there is no noninvasive method to determine tumoral tenascin-C expression in vivo. To address the need for an agent to image and quantify tenascin-C, we report the development of a radioactive PET tracer based on a tenascin-C-specific single-stranded DNA aptamer (tenascin-C aptamer).
  
  
  METHODS
  Tenascin-C aptamer was radiolabeled with (18)F and (64)Cu. PET imaging studies for the evaluation of tumor uptake and pharmacokinetics of tenascin-C aptamer were performed in comparison to a nonspecific scrambled aptamer (Sc aptamer).
  
  
  RESULTS
  The labeled tenascin-C aptamer provided clear visualization of tenascin-C-positive but not tenascin-C-negative tumors. The uptake of tenascin-C aptamer was significantly higher than that of Sc aptamer in tenascin-C-positive tumors. The labeled tenascin-C aptamer had fast clearance from the blood and other nonspecific organs through the kidneys, resulting in high tumor contrast.
  
  
  CONCLUSIONS
  Our data suggest that suitably labeled tenascin-C aptamer can be used as a PET tracer to image tumor expression of tenascin-C with a high tumor-to-background ratio and might provide insightful and personalized medical data that will help determine appropriate treatment and monitoring.
authors.affiliation: Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland.
authors.forename: Orit
authors.initials: O
authors.lastname: Jacobson
authors.affiliation: Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland Department of Radiology, The Fourth Hospital of Harbin Medical University, Harbin, Heilongjiang, China.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Yan
authors.affiliation: Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland.
authors.forename: Gang
authors.initials: G
authors.lastname: Niu
authors.affiliation: Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health, Bethesda, Maryland; and.
authors.forename: Ido D
authors.initials: ID
authors.lastname: Weiss
authors.affiliation: Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland.
authors.forename: Ying
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Positron Emission Tomography Department, Warren Grant Magnuson Clinical Center (CC), National Institutes of Health, Bethesda, Maryland.
authors.forename: Lawrence P
authors.initials: LP
authors.lastname: Szajek
authors.affiliation: Department of Radiology, The Fourth Hospital of Harbin Medical University, Harbin, Heilongjiang, China.
authors.forename: Baozhong
authors.initials: B
authors.lastname: Shen
authors.affiliation: Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland.
authors.forename: Dale O
authors.initials: DO
authors.lastname: Kiesewetter
authors.affiliation: Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland shawn.chen@nih.gov.
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Chen
mesh_terms: D000818:Animals; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D045744:Cell Line, Tumor; D003301:Copper Radioisotopes / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry; D003952:Diagnostic Imaging; D005260:Female; D005462:Fluorine Radioisotopes / Q000737:chemistry*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D008856:Microscopy, Fluorescence; D009368:Neoplasm Transplantation; D009690:Nucleic Acid Conformation; D009711:Nucleotides / Q000737:chemistry; D049268:Positron-Emission Tomography / Q000379:methods*; D011849:Radioactive Tracers; D019275:Radiopharmaceuticals; D019063:Tenascin / Q000737:chemistry*
chemical_list: D052157:Aptamers, Nucleotide; D003301:Copper Radioisotopes; D004277:DNA, Single-Stranded; D005462:Fluorine Radioisotopes; D009711:Nucleotides; D011849:Radioactive Tracers; D019275:Radiopharmaceuticals; D019063:Tenascin
keywords: DNA aptamer; PET; tenascin-C