title: Evaluation of the therapeutic efficacy of a VEGFR2-blocking antibody using sodium-iodide symporter molecular imaging in a tumor xenograft model.
abstract: OBJECTIVE
  Vascular endothelial growth factor receptor 2-blocking antibody (DC101) has inhibitory effects on tumor growth and angiogenesis in vivo. The human sodium/iodide symporter (hNIS) gene has been shown to be a useful molecular imaging reporter gene. Here, we investigated the evaluation of therapeutic efficacy by molecular imaging in reporter gene transfected tumor xenografts using a gamma imaging system.
  
  
  METHODS
  The hNIS gene was transfected into MDA-MB-231 cells using Lipofectamine. The correlation between the number of MDA-MB-231-hNIS cells and the uptake of (99m)Tc-pertechnetate or (125)I was investigated in vitro by gamma imaging and counting. MDA-MB-231-hNIS cells were injected subcutaneously into mice. When the tumor volume reached 180-200 mm(3), we randomly assigned five animals to each of three groups representing different tumor therapies; no DC101 (control), 100 μg, or 150 μg DC101/mouse. One week and 2 weeks after the first injection of DC101, gamma imaging was performed. Mice were sacrificed 2 weeks after the first injection of DC101. The tumor tissues were used for reverse transcriptase-polymerase chain reaction (RT-PCR) and CD31 staining.
  
  
  RESULTS
  Uptake of (125)I and (99m)Tc-pertechnetate into MDA-MB-231-hNIS cells in vitro showed correlation with the number of cells. In DC101 treatment groups, the mean tumor volume was smaller than that of the control mice. Furthermore, tumor uptake of (125)I was lower than in the controls. The CD31 staining and RT-PCR assay results showed that vessel formation and expression of the hNIS gene were significantly reduced in the tumor tissues of treatment groups.
  
  
  CONCLUSIONS
  This study demonstrated the power of molecular imaging using a gamma imaging system for evaluating the therapeutic efficacy of an antitumor treatment. Molecular imaging systems may be useful in evaluation and development of effective diagnostic and/or therapeutic antibodies for specific target molecules.
authors.affiliation: Department of Nuclear Medicine, Chonbuk National University Medical School, Jeonju-si, Jeonbuk 561-712, Republic of Korea.
authors.forename: Su-Jin
authors.initials: SJ
authors.lastname: Cheong
authors.forename: Chang-Moon
authors.initials: CM
authors.lastname: Lee
authors.forename: Eun-Mi
authors.initials: EM
authors.lastname: Kim
authors.forename: Tai-Boong
authors.initials: TB
authors.lastname: Uhm
authors.forename: Hwan-Jeong
authors.initials: HJ
authors.lastname: Jeong
authors.forename: Dong Wook
authors.initials: DW
authors.lastname: Kim
authors.forename: Seok Tae
authors.initials: ST
authors.lastname: Lim
authors.forename: Myung-Hee
authors.initials: MH
authors.lastname: Sohn
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000494:pharmacology* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000098:blood supply / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D002452:Cell Count; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D057054:Molecular Imaging / Q000379:methods*; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000378:metabolism; D051381:Rats; D027981:Symporters / Q000378:metabolism*; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden / Q000187:drug effects; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000276:immunology*; D023041:Xenograft Model Antitumor Assays; D000099209:Sodium-Iodide Symporters
chemical_list: D000911:Antibodies, Monoclonal; D027981:Symporters; D040301:Vascular Endothelial Growth Factor Receptor-2; D000099209:Sodium-Iodide Symporters; C511761:DC101 monoclonal antibody