title: Specific detection of CD133-positive tumor cells with iron oxide nanoparticles labeling using noninvasive molecular magnetic resonance imaging.
abstract: BACKGROUND
  The use of ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles to visualize cells has been applied clinically, showing the potential for monitoring cells in vivo with magnetic resonance imaging (MRI). USPIO conjugated with anti-CD133 antibodies (USPIO-CD133 Ab) that recognize the CD133 molecule, a cancer stem cell marker in a variety of cancers, was studied as a novel and potent agent for MRI contrast enhancement of tumor cells.
  
  
  METHODS
  Anti-CD133 antibodies were used to conjugate with USPIO via interaction of streptavidin and biotin for in vivo labeling of CD133-positive cells in xenografted tumors and N-ethyl-N-nitrosourea (ENU)-induced brain tumors. The specific binding of USPIO-CD133 Ab to CD133-positive tumor cells was subsequently detected by Prussian blue staining and MRI with T2-weighted, gradient echo and multiple echo recombined gradient echo images. In addition, the cellular toxicity of USPIO-CD133 Ab was determined by analyzing cell proliferation, apoptosis, and reactive oxygen species production.
  
  
  RESULTS
  USPIO-CD133 Ab specifically recognizes in vitro and labels CD133-positive cells, as validated using Prussian blue staining and MRI. The assays of cell proliferation, apoptosis, and reactive oxygen species production showed no significant differences in tumor cells with or without labeling of USPIO-CD133 Ab. In vivo imaging of CD133-positive cells was demonstrated by intravenous injection of USPIO-CD133 Ab in mice with HT29 xenografted tumors. The MRI of HT29 xenografts showed several clusters of hypotensive regions that correlated with CD133 expression and Prussian blue staining for iron. In rat, brain tumors induced by transplacental ENU mutagenesis, several clusters of hypointensive zones were observed in CD133-expressing brain tumors by MRI and intravenously administered USPIO-CD133 Ab.
  
  
  CONCLUSIONS
  Combination of USPIO-CD133 Ab and MRI is valuable in recognizing CD133-expressing tumor cells in vitro, extracellularly labeling for cell tracking and detecting CD133-expressing tumors in xenografted tumors as well as ENU-induced rat brain tumors.
authors.affiliation: National Institute of Cancer Research, National Health Research Institutes, Miaoli, Taiwan ; Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan.
authors.forename: Ya-Wen
authors.initials: YW
authors.lastname: Chen
authors.affiliation: Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli, Taiwan.
authors.forename: Gunn-Guang
authors.initials: GG
authors.lastname: Liou
authors.affiliation: Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan ; School of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Huay-Ben
authors.initials: HB
authors.lastname: Pan
authors.affiliation: School of Medicine, National Yang-Ming University, Taipei, Taiwan ; Department of Pathology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
authors.forename: Hui-Hwa
authors.initials: HH
authors.lastname: Tseng
authors.affiliation: Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan.
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Hung
authors.affiliation: Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan ; School of Medicine, National Yang-Ming University, Taipei, Taiwan ; Department of Medical Laboratory Sciences and Biotechnology, Fooyin University, Kaohsiung, Taiwan ; School of Medicine, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Chen-Pin
authors.initials: CP
authors.lastname: Chou
mesh_terms: D000071916:AC133 Antigen; D000818:Animals; D000906:Antibodies / Q000378:metabolism; D015703:Antigens, CD / Q000378:metabolism*; D001932:Brain Neoplasms / Q000175:diagnosis / Q000473:pathology; D016923:Cell Death; D003911:Dextrans / Q000737:chemistry*; D005038:Ethylnitrosourea; D006023:Glycoproteins / Q000378:metabolism*; D019073:HT29 Cells; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D051379:Mice; D057054:Molecular Imaging / Q000379:methods*; D010455:Peptides / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D013194:Staining and Labeling; D023041:Xenograft Model Antitumor Assays
chemical_list: D000071916:AC133 Antigen; D000906:Antibodies; D015703:Antigens, CD; D003911:Dextrans; D006023:Glycoproteins; D058185:Magnetite Nanoparticles; C000606023:PROM1 protein, human; D010455:Peptides; C000606024:Prom1 protein, mouse; C000606025:Prom1 protein, rat; C097921:ferumoxtran-10; D005038:Ethylnitrosourea
keywords: CD133; MRI; USPIO; USPIO-CD133 Ab; molecular imaging