title: Changes in signaling pathways induced by vandetanib in a human medullary thyroid carcinoma model, as analyzed by reverse phase protein array.
abstract: BACKGROUND
  Medullary thyroid carcinoma (MTC) is a rare tumor that is caused by activating mutations in the proto-oncogene RET. Vandetanib, a tyrosine-kinase inhibitor, has been recently approved to treat adult patients with metastatic MTC. The aim of this study was to investigate changes in signaling pathways induced by vandetanib treatment in preclinical MTC models, using the reverse-phase protein array method (RPPA).
  
  
  METHODS
  The human TT cell line was used to assess in vitro and in vivo activity of vandetanib. Protein extracts from TT cells or TT xenografted mice, treated by increasing concentrations of vandetanib for different periods of time, were probed with a set of 12 antibodies representing major signaling pathways, using RPPA. Results were validated using two distinct protein detection methods: Western immunoblotting and immunohistochemistry.
  
  
  RESULTS
  Vandetanib displays antiproliferative and antiangiogenic activities and inhibits RET autophosphorylation. The MAPK and AKT pathways were the two major signaling pathways inhibited by vandetanib. Interestingly, phosphorylated levels of NFκB-p65 were significantly increased by vandetanib. Comparable results were obtained in both the in vitro and in vivo approaches, as well as for the protein detection methods. However, some discrepancies were observed between RPPA and Western immunoblotting, possibly due to lack of specificity of the primary antibodies used.
  
  
  CONCLUSIONS
  Overall, our results confirmed the interest of RPPA for screening global changes induced in signaling pathways by kinase inhibitors. MAPK and AKT were identified as the main pathways involved in vandetanib response in MTC models. Our results also suggest alternative routes for controlling the disease, and provide a rationale for the development of therapeutic combinations based on the comprehensive identification of molecular events induced by inhibitors.
authors.affiliation: 1 Genetic Stability and Oncogenesis Research Unit, National Center for Scientific Research (CNRS UMR 8200), Gustave Roussy and University of Paris-Sud , Villejuif, France .
authors.forename: Sophie
authors.initials: S
authors.lastname: Broutin
authors.forename: Frédéric
authors.initials: F
authors.lastname: Commo
authors.forename: Leanne
authors.initials: L
authors.lastname: De Koning
authors.forename: Bérengère
authors.initials: B
authors.lastname: Marty-Prouvost
authors.forename: Ludovic
authors.initials: L
authors.lastname: Lacroix
authors.forename: Monique
authors.initials: M
authors.lastname: Talbot
authors.forename: Bernard
authors.initials: B
authors.lastname: Caillou
authors.forename: Thierry
authors.initials: T
authors.lastname: Dubois
authors.forename: Anderson J
authors.initials: AJ
authors.lastname: Ryan
authors.forename: Corinne
authors.initials: C
authors.lastname: Dupuy
authors.forename: Martin
authors.initials: M
authors.lastname: Schlumberger
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Bidart
mesh_terms: D000328:Adult; D000818:Animals; D018278:Carcinoma, Neuroendocrine; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects; D051379:Mice; D010880:Piperidines / Q000627:therapeutic use*; D000090063:Proto-Oncogene Mas; D051057:Proto-Oncogene Proteins c-akt / Q000187:drug effects; D011799:Quinazolines / Q000627:therapeutic use*; D015398:Signal Transduction / Q000187:drug effects; D013964:Thyroid Neoplasms / Q000188:drug therapy*
chemical_list: C000715470:MAS1 protein, human; D010880:Piperidines; D000090063:Proto-Oncogene Mas; D011799:Quinazolines; D051057:Proto-Oncogene Proteins c-akt; C452423:vandetanib