title: Thyroid stimulating hormone increases iodine uptake by thyroid cancer cells during BRAF silencing.
abstract: BACKGROUND
  The BRAF(V600E) mutation is present in 62% of radioactive iodine-resistant thyroid tumors and is associated with downregulation of the sodium-iodide symporter (NIS) and thyroid stimulating hormone receptor (TSHr). We sought to evaluate the combined effect of BRAF inhibition and TSH supplementation on (131)I uptake of BRAF(V600E)-mutant human thyroid cancer cells.
  
  
  METHODS
  WRO cells (a BRAF(V600E)-mutant follicular-derived papillary thyroid carcinoma cell line) were transfected with small interfering RNA targeting BRAF for 72 h in a physiological TSH environment. NIS and TSHr expression were then evaluated at three levels: gene expression, protein levels, and (131)I uptake. These three main outcomes were then reassessed in TSH-depleted media and media supplemented with supratherapeutic concentrations of TSH.
  
  
  RESULTS
  NIS gene expression increased 5.5-fold 36 h after transfection (P = 0.01), and TSHr gene expression increased 2.8-fold at 24 h (P = 0.02). NIS and TSHr protein levels were similarly increased 48 and 24 h after transfection, respectively. Seventy-two hours after BRAF inhibition, (131)I uptake was unchanged in TSH-depleted media, increased by 7.5-fold (P < 0.01) in physiological TSH media, and increased by 9.1-fold (P < 0.01) in supratherapeutic TSH media.
  
  
  CONCLUSIONS
  The combined strategy of BRAF inhibition and TSH supplementation results in greater (131)I uptake than when either technique is used alone. This represents a simple and feasible approach that may improve outcomes in patients with radioactive iodine-resistant thyroid carcinomas for which current treatment algorithms are ineffective.
authors.affiliation: Division of Endocrine and Minimally Invasive Surgery, Department of Surgery, New York Presbyterian Hospital-Weill Cornell Medical College, New York, New York, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Kleiman
authors.forename: Daniel
authors.initials: D
authors.lastname: Buitrago
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Crowley
authors.forename: Toni
authors.initials: T
authors.lastname: Beninato
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Veach
authors.forename: Pat B
authors.initials: PB
authors.lastname: Zanzonico
authors.forename: Moonsoo
authors.initials: M
authors.lastname: Jin
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Fahey
authors.forename: Rasa
authors.initials: R
authors.lastname: Zarnegar
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D020868:Gene Silencing / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007455:Iodine / Q000378:metabolism*; D007457:Iodine Radioisotopes; D009154:Mutation / Q000235:genetics; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D034741:RNA, Small Interfering / Q000494:pharmacology; D011989:Receptors, Thyrotropin / Q000378:metabolism; D027981:Symporters / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000378:metabolism* / Q000473:pathology; D013972:Thyrotropin / Q000494:pharmacology*; D014162:Transfection; D000099209:Sodium-Iodide Symporters
chemical_list: D007455:Iodine; D007457:Iodine Radioisotopes; D048493:Proto-Oncogene Proteins B-raf; D034741:RNA, Small Interfering; D011989:Receptors, Thyrotropin; D027981:Symporters; D013972:Thyrotropin; D000099209:Sodium-Iodide Symporters; C482119:BRAF protein, human