title: Sunitinib exerts only limited effects on the proliferation and differentiation of anaplastic thyroid cancer cells.
abstract: BACKGROUND
  Novel molecularly targeted drugs are undergoing preclinical and clinical testing to assess their efficacy against refractory thyroid carcinomas. The multikinase inhibitor Sunitinib has been shown to inhibit the kinase activity of the RET oncogene and reduce proliferation in differentiated thyroid cancer cells harboring the RET/PTC rearrangement. In this study, we evaluated its effects in human cell lines derived from differentiated (TPC-1) and anaplastic (8505C, CAL-62, and C643) thyroid cancers.
  
  
  METHODS
  The cells exposed to various concentrations of Sunitinib were examined for: (1) cell viability and presence of apoptosis, analyzed by cell counts, MTT assay, trypan blue exclusion assay, western blotting, and immunofluorescence; (2) expression of cyclin D1 and phosphorylated and nonphosphorylated extracellular signal-regulated kinase (ERK) and Akt proteins, analyzed by western blotting; and (3) transcription of genes encoding thyrocyte differentiation markers (thyroid-stimulating hormone receptor, sodium/iodide symporter, thyroglobulin, and thyroperoxidase) and proangiogenic factors (vascular endothelial growth factor A, platelet-derived growth factors A and B), measured by quantitative reverse transcriptase-polymerase chain reaction.
  
  
  RESULTS
  Exposure to nanomolar concentrations of Sunitinib significantly reduced cell viability in only TPC-1 cells, and this effect was paralleled by reduction of cyclin D1 levels. Western blotting revealed reduced phosphorylation of ERK and Akt after 3 and 6 hours of drug exposure. In contrast, the growth of 8505C, CAL-62, and C-643 cells was significantly reduced only by micromolar concentrations of Sunitinib, mainly due to induced necrotic rather than apoptotic death. In these cells, Sunitinib exerted a few significant effects on the transcription of angiogenic factors or thyrocyte differentiation markers.
  
  
  CONCLUSIONS
  Sunitinib has little or no effect on the growth or differentiation of anaplastic thyroid cancer cells, thus suggesting that it is unlikely to be effective in the treatment of anaplastic thyroid cancer.
authors.affiliation: Department of Pharmacobiological Sciences, University of Catanzaro Magna Graecia, Catanzaro, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: D'Agostino
authors.forename: Pasquale
authors.initials: P
authors.lastname: Voce
authors.forename: Marilena
authors.initials: M
authors.lastname: Celano
authors.forename: Marialuisa
authors.initials: M
authors.lastname: Sponziello
authors.forename: Sonia
authors.initials: S
authors.lastname: Moretti
authors.forename: Valentina
authors.initials: V
authors.lastname: Maggisano
authors.forename: Antonella
authors.initials: A
authors.lastname: Verrienti
authors.forename: Cosimo
authors.initials: C
authors.lastname: Durante
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Filetti
authors.forename: Efisio
authors.initials: E
authors.lastname: Puxeddu
authors.forename: Diego
authors.initials: D
authors.lastname: Russo
mesh_terms: D043925:Angiogenesis Inducing Agents / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D019938:Cyclin D1 / Q000032:analysis; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D007453:Iodide Peroxidase / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D051058:Oncogene Protein v-akt / Q000378:metabolism; D010766:Phosphorylation; D011758:Pyrroles / Q000494:pharmacology*; D011989:Receptors, Thyrotropin / Q000378:metabolism; D000077210:Sunitinib; D027981:Symporters / Q000378:metabolism; D013954:Thyroglobulin / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000188:drug therapy*; D000099209:Sodium-Iodide Symporters
chemical_list: D043925:Angiogenesis Inducing Agents; D000970:Antineoplastic Agents; D019938:Cyclin D1; D007211:Indoles; D007453:Iodide Peroxidase; D051058:Oncogene Protein v-akt; D011758:Pyrroles; D011989:Receptors, Thyrotropin; D000077210:Sunitinib; D027981:Symporters; D013954:Thyroglobulin; D000099209:Sodium-Iodide Symporters