title: Dedifferentiation of differentiated thyroid carcinoma cell line FTC-133 is enhanced by 131I pretreatment.
abstract: BACKGROUND
  Differentiated thyroid carcinoma (DTC) usually has a high iodine uptake. However, dedifferentiation of DTC with decreased or no radioiodine ((131)I) uptake is observed in clinical practice, with poor prognosis. The aim of this study was to investigate the effects of (131)I radiation on radioiodine uptake (RAIU) and the expression of thyroid-specific molecules.
  
  
  METHODS
  FTC-133 cells were treated with (131)I, the dosage dictated by methylthiazol tetrazolium test results and preliminary experiments. The experimental cell group was incubated with (131)I for 48 h and then cultured for 3 months in (131)I-free medium. The control group was set without (131)I. Primary cells were defined as the blank group. Following treatment, RAIU was measured with a gamma counter as the counts/cell number. Na(+)/I(-) symporter (NIS), thyroid-stimulating hormone receptor (TSHR), thyroid peroxidase (TPO) and thyroglobulin (Tg) levels were detected by Western blotting and radioimmunoassay, and their mRNAs were detected by real-time polymerase chain reaction.
  
  
  RESULTS
  RAIU of FTC-133 cells decreased gradually after coincubation with (131)I and did not recover even if (131)I was removed. The relative RAIU of the control and experimental groups was 0.567 and 0.182, respectively, a statistically significant difference (P<.01). Expression of NIS, TSHR, TPO and Tg decreased in the experimental group to a statistically significant degree compared to that of controls (P<.05).
  
  
  CONCLUSIONS
  Changes in the mRNA levels were in accordance with the expression of thyroid-specific proteins. Thus, FTC-133 cells undergo dedifferentiation during long-term culture in vitro, and (131)I may promote this progress.
authors: Department of Nuclear Medicine, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
authors: Fang
authors: F
authors: Feng
authors: Hui
authors: H
authors: Wang
authors: Hongliang
authors: H
authors: Fu
authors: Shuqi
authors: S
authors: Wu
authors: Zhiyi
authors: Z
authors: Ye
authors: Suyun
authors: S
authors: Chen
authors: Jianing
authors: J
authors: Li
mesh_terms: D001692:Biological Transport / Q000528:radiation effects; D054337:Cell Dedifferentiation / Q000528:radiation effects*; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000528:radiation effects; D015972:Gene Expression Regulation, Neoplastic / Q000528:radiation effects; D006801:Humans; D007453:Iodide Peroxidase / Q000235:genetics; D007457:Iodine Radioisotopes / Q000009:adverse effects / Q000378:metabolism / Q000627:therapeutic use; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011989:Receptors, Thyrotropin / Q000235:genetics; D027981:Symporters / Q000235:genetics; D013954:Thyroglobulin / Q000235:genetics; D013964:Thyroid Neoplasms / Q000235:genetics / Q000473:pathology* / Q000532:radiotherapy*; D000099209:Sodium-Iodide Symporters
chemical_list: D007453:Iodide Peroxidase; D007457:Iodine Radioisotopes; D012333:RNA, Messenger; D011989:Receptors, Thyrotropin; D027981:Symporters; D013954:Thyroglobulin; D000099209:Sodium-Iodide Symporters