The Oncologist ® Endocrinology Targeting BRAF V600E with PLX4720 Displays Potent Antimigratory and Anti-invasive Activity in Preclinical Models of Human Thyroid Cancer CARMELO NUCERA,a,e MATTHEW A. NEHS,a SUSHRUTA S. NAGARKATTI,a PETER M. SADOW,b MICHAL MEKEL,a ANDREW H. FISCHER,c PAUL S. LIN,d GIDEON E. BOLLAG,d JACK LAWLER,e RICHARD A. HODIN,a SAREH PARANGIa aThyroid Cancer Research Laboratory, Endocrine Surgery Unit, and bDepartment of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA; cDepartment of Pathology, University of Massachusetts, Worcester, Massachusetts, USA; dPlexxikon Inc., Berkeley, California, USA; eDivision of Cancer Biology and Angiogenesis, Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA Key Words. BRAFV600E inhibitor Anaplastic thyroid cancer Metastasis Invasion Orthotopic Primary human normal thyroid follicular cells Mutation Disclosures: Carmelo Nucera: None; Matthew A. Nehs: None; Sushruta S. Nagarkatti: None; Peter M. Sadow: None; Michal Mekel: None; Andrew H. Fischer: None; Paul S. Lin: Employment/leadership position: Plexxikon Inc.; Ownership interest: Plexxikon Inc.; Gideon E. Bollag: Employment/leadership position: Plexxikon Inc.; Intellectual property rights/inventor/patent holder: filings through Plexxikon Inc.; Ownership interest: Plexxikon Inc.; Jack Lawler: None; Richard A. Hodin: None; Sareh Parangi: None. The content of this article has been reviewed by independent peer reviewers to ensure that it is balanced, objective, and free from commercial bias. No financial relationships relevant to the content of this article have been disclosed by the independent peer reviewers. ABSTRACT Purpose. B-RafV600E may play a role in the progression from papillary thyroid cancer to anaplastic thyroid can- cer (ATC). We tested the effects of a highly selective B-RafV600E inhibitor, PLX4720, on proliferation, migra- tion, and invasion both in human thyroid cancer cell lines (8505cB-RafV600E and TPC-1RET/PTC-1 and wild-type B-Raf) and in primary human normal thyroid (NT) follicular cells engineered with or without B-RafV600E. Experimental Design. Large-scale genotyping analysis by mass spectrometry was performed in order to ana- lyze >900 gene mutations. Cell proliferation and migra- tion/invasion were performed upon PLX4720 treatment in 8505c, TPC-1, and NT cells. Orthotopic implantation of either 8505c or TPC-1 cells into the thyroid of severe combined immunodeficient mice was performed. Gene validations were performed by quantitative polymerase chain reaction and immunohistochemistry. Results. We found that PLX4720 reduced in vitro cell proliferation and migration and invasion of 8505c cells, causing early downregulation of genes involved in tu- mor progression. PLX4720-treated NT cells overex- pressing B-RafV600E (heterozygous wild-type B-Raf/ Correspondence: Sareh Parangi, M.D., Harvard Medical School, Massachusetts General Hospital, Unit of Endocrine Surgery, Wang ACC 460, 15 Parkman Street, Boston, Massachusetts 02115, USA. Telephone: 617-643-4806; Fax: 617-643-4802; e-mail: sparangi@partners.org Received September 19, 2010; accepted for publication January 20, 2011; first published online in The Oncol- ogist Express on February 25, 2011; available online without subscription through the open access option. ©AlphaMed Press 1083-7159/ 2011/$30.00/0 doi: 10.1634/theoncologist.2010-0317 The Oncologist 2011;16:296 –309 www.TheOncologist.com