title: The Effect of Tanespimycin (17-AAG) on Radioiodine Accumulation in Sodium-Iodide Symporter Expressing Cells.
abstract: OBJECTIVE
  The heat shock protein 90 inhibitor, tanespimycin, is an anticancer agent known to increase iodine accumulation in normal and cancerous thyroid cells. Iodine accumulation is regulated by membrane proteins such as sodium iodide symporter (NIS) and pendrin (PDS), and thus we attempted to characterize the effects of tanespimycin on those genes.
  
  
  METHODS
  Cells were incubated with tanespimycin in order to evaluate (125)I accumulation and efflux ability. Radioiodine uptake and efflux were measured by a gamma counter and normalized by protein amount. RT-PCR were performed to measure the level of gene expression.
  
  
  RESULTS
  After tanespimycin treatment, (125)I uptake was increased by ∼2.5-fold in FRTL-5, hNIS-ARO, and hNIS-MDA-MB-231 cells, but no changes were detected in the hNIS-HeLa cells. Tanespimycin significantly reduced the radioiodine efflux rate only in the FRTL-5 cells. In the FRTL-5 and hNIS-ARO cells, PDS mRNA levels were markedly reduced; the only other observed alteration in the levels of NIS mRNA after tanespimycin treatment was an observed increase in the hNIS-ARO cells.
  
  
  CONCLUSIONS
  These results indicate that cellular responses against tanespimycin treatment differed between the normal rat thyroid cells and human cancer cells, and the reduction in the (125)I efflux rate by tanespimycin in the normal rat thyroid cells might be attributable to reduced PDS gene expression.
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, #207-4, Samsung Cancer Research Building, 28 Yeongeon-dong, Jongno-gu, Seoul, 110-744 Korea ; Department of Tumor Biology, Seoul National University College of Medicine, Seoul, Korea ; Laboratory of Molecular Imaging and Therapy, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Kyoung Hyun
authors.initials: KH
authors.lastname: Yu
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, #207-4, Samsung Cancer Research Building, 28 Yeongeon-dong, Jongno-gu, Seoul, 110-744 Korea ; Laboratory of Molecular Imaging and Therapy, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea ; Cancer Imaging Center, Seoul National University Cancer Hospital, Seoul, Korea.
authors.forename: Hyewon
authors.initials: H
authors.lastname: Youn
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, #207-4, Samsung Cancer Research Building, 28 Yeongeon-dong, Jongno-gu, Seoul, 110-744 Korea ; Department of Tumor Biology, Seoul National University College of Medicine, Seoul, Korea ; Laboratory of Molecular Imaging and Therapy, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Myung Geun
authors.initials: MG
authors.lastname: Song
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, #207-4, Samsung Cancer Research Building, 28 Yeongeon-dong, Jongno-gu, Seoul, 110-744 Korea ; Department of Molecular Medicine and Biopharmaceutical Science, WCU Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Korea.
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Lee
authors.affiliation: Department of Nuclear Medicine, Seoul National University College of Medicine, #207-4, Samsung Cancer Research Building, 28 Yeongeon-dong, Jongno-gu, Seoul, 110-744 Korea ; Department of Tumor Biology, Seoul National University College of Medicine, Seoul, Korea ; Laboratory of Molecular Imaging and Therapy, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: June-Key
authors.initials: JK
authors.lastname: Chung
keywords: Pendrin; Radioiodine therapy; Sodium-iodide symporter; Tanespimycin (17-AAG); Thyroid cancer