title: An in vitro and in vivo evaluation of a reporter gene/probe system hERL/(18)F-FES.
abstract: OBJECTIVE
  To evaluate the feasibility of a reporter gene/probe system, namely the human estrogen receptor ligand binding domain (hERL)/16α-[(18)F] fluoro-17β-estradiol ((18)F-FES), for monitoring gene and cell therapy.
  
  
  METHODS
  The recombinant adenovirus vector Ad5-hERL-IRES-VEGF (Ad-EIV), carrying a reporter gene (hERL) and a therapeutic gene (vascular endothelial growth factor, VEGF165) through an internal ribosome entry site (IRES), was constructed. After transfection of Ad-EIV into bone marrow mesenchymal stem cells (Ad-EIV-MSCs), hERL and VEGF165 mRNA and protein expressions were identified using Real-Time qRT-PCR and immunofluorescence. The uptake of (18)F-FES was measured in both Ad-EIV-MSCs and nontransfected MSCs after different incubation time. Micro-PET/CT images were obtained at 1 day after injection of Ad-EIV-MSCs into the left foreleg of the rat. The right foreleg was injected with nontransfected MSCs, which served as self-control.
  
  
  RESULTS
  After transfection with Ad-EIV, the mRNA and protein expression of hERL and VEGF165 were successfully detected in MSCs, and correlated well with each other (R(2) = 0.9840, P<0.05). This indicated the reporter gene could reflect the therapeutic gene indirectly. Ad-EIV-MSCs uptake of (18)F-FES increased with incubation time with a peak value of 9.13%±0.33% at 150 min, which was significantly higher than that of the control group. A far higher level of radioactivity could be seen in the left foreleg on the micro-PET/CT image than in the opposite foreleg.
  
  
  CONCLUSIONS
  These preliminary in vitro and in vivo studies confirmed that hERL/(18)F-FES might be used as a novel reporter gene/probe system for monitoring gene and cell therapy. This imaging platform may have broad applications for basic research and clinical studies.
authors.affiliation: Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Chunxia
authors.initials: C
authors.lastname: Qin
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Lan
authors.forename: Jiang
authors.initials: J
authors.lastname: He
authors.forename: Xiaotian
authors.initials: X
authors.lastname: Xia
authors.forename: Yueli
authors.initials: Y
authors.lastname: Tian
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Pei
authors.forename: Hui
authors.initials: H
authors.lastname: Yuan
authors.forename: Yongxue
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D015342:DNA Probes / Q000378:metabolism*; D004705:Endocytosis; D004958:Estradiol / Q000031:analogs & derivatives* / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D017930:Genes, Reporter; D006801:Humans; D008024:Ligands; D059630:Mesenchymal Stem Cells / Q000378:metabolism; D049268:Positron-Emission Tomography; D017434:Protein Structure, Tertiary; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D011960:Receptors, Estrogen / Q000737:chemistry* / Q000378:metabolism*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics
chemical_list: D015415:Biomarkers; D015342:DNA Probes; D008024:Ligands; D011960:Receptors, Estrogen; D042461:Vascular Endothelial Growth Factor A; D004958:Estradiol; C043436:16-fluoroestradiol