title: Detection of increased 64Cu uptake by human copper transporter 1 gene overexpression using PET with 64CuCl2 in human breast cancer xenograft model.
abstract: Copper is an essential cofactor for a variety of biochemical processes including oxidative phosphorylation, cellular antioxidant activity, and elimination of free radicals. The copper transporter 1 is known to be involved in cellular uptake of copper ions. In this study, we evaluated the utility of human copper transporter 1 (hCTR1) gene as a new reporter gene for (64)Cu PET imaging.
  
  
  METHODS
  Human breast cancer cells (MDA-MB-231) were infected with a lentiviral vector constitutively expressing the hCTR1 gene under super cytomegalovirus promoter, and positive clones (MDA-MB-231-hCTR1) were selected. The expression of hCTR1 gene in MDA-MB-231-hCTR1 cells was measured by reverse transcription polymerase chain reaction, Western blot, and (64)Cu uptake assay. To evaluate the cytotoxic effects induced by hCTR1 expression, the dose-dependent cell survival rate after treatment with cisplatin (Cis-diaminedichloroplatinum (II) [CDDP]) was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and trypan blue dye exclusion. Small-animal PET images were acquired in tumor-bearing mice from 2 to 48 h after an intravenous injection of (64)Cu.
  
  
  RESULTS
  The hCTR1 gene expression in MDA-MB-231-hCTR1 cells was confirmed at the RNA and protein expression and the cellular (64)Cu uptake level. MTT assay and trypan blue dye exclusion showed that the cell viability of MDA-MB-231-hCTR1 cells decreased more rapidly than that of MDA-MB-231 cells after treatment with CDDP for 96 or 72 h, respectively. Small-animal PET imaging revealed a higher accumulation of (64)Cu in MDA-MB-231-hCTR1 tumors than in MDA-MB-231 tumors. With respect to the biodistribution data, the percentage injected dose per gram of (64)Cu in the MDA-MB-231 tumors and MDA-MB-231-hCTR1 tumors at 48 h after (64)Cu injection was 2.581 ± 0.254 and 5.373 ± 1.098, respectively.
  
  
  CONCLUSIONS
  An increase in (64)Cu uptake induced by the expression of hCTR1 gene was demonstrated in vivo and in vitro, suggesting the potential use of hCTR1 gene as a new imaging reporter gene for PET with (64)CuCl2.
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Korea; and.
authors.forename: Kwang Il
authors.initials: KI
authors.lastname: Kim
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Korea; and.
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Jang
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Korea; and.
authors.forename: Ju Hui
authors.initials: JH
authors.lastname: Park
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Korea; and.
authors.forename: Yong Jin
authors.initials: YJ
authors.lastname: Lee
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Korea; and.
authors.forename: Tae Sup
authors.initials: TS
authors.lastname: Lee
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Korea; and.
authors.forename: Kwang Sun
authors.initials: KS
authors.lastname: Woo
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Korea; and.
authors.forename: Hyun
authors.initials: H
authors.lastname: Park
authors.affiliation: Department of Nuclear Medicine, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea.
authors.forename: Jae Gol
authors.initials: JG
authors.lastname: Choe
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Korea; and kang2325@kirams.re.kr gwangil@kirams.re.kr.
authors.forename: Gwang Il
authors.initials: GI
authors.lastname: An
authors.affiliation: Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul, Korea; and kang2325@kirams.re.kr gwangil@kirams.re.kr.
authors.forename: Joo Hyun
authors.initials: JH
authors.lastname: Kang
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D027682:Cation Transport Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology; D003300:Copper / Q000493:pharmacokinetics; D003301:Copper Radioisotopes / Q000493:pharmacokinetics*; D000079923:Copper Transporter 1; D015972:Gene Expression Regulation, Neoplastic; D017930:Genes, Reporter; D006801:Humans; D007700:Kinetics; D051379:Mice; D049268:Positron-Emission Tomography / Q000379:methods*; D013778:Tetrazolium Salts; D013844:Thiazoles; D023041:Xenograft Model Antitumor Assays
chemical_list: D027682:Cation Transport Proteins; D003301:Copper Radioisotopes; D000079923:Copper Transporter 1; C490079:SLC31A1 protein, human; D013778:Tetrazolium Salts; D013844:Thiazoles; D003300:Copper; C022616:thiazolyl blue; D002945:Cisplatin; C029892:cupric chloride
keywords: 64Cu; PET; cisplatin; hCTR1; reporter gene