The mitogen-activated protein kinase pathway facilitates resistance to the src inhibitor dasatinib in thyroid cancer

Thomas C. Beadnell, Katie M. Mishall, Qiong Zhou, Stephen M. Riffert, Kelsey E. Wuensch, Brittelle E. Kessler, Maia L. Corpuz, Xia Jing, Jihye Kim, Guoliang Wang, Aik Choon Tan, Rebecca E. Schweppe

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

Advanced stages of papillary and anaplastic thyroid cancer represent a highly aggressive subset, in which there are currently few effective therapies. We and others have recently demonstrated that c-SRC is a key mediator of growth, invasion, and metastasis, and therefore represents a promising therapeutic target in thyroid cancer. However, clinically, Src inhibitor efficacy has been limited, and therefore further insights are needed to define resistance mechanisms and determine rational combination therapies. We have generated four thyroid cancer cell lines with a greater than 30-fold increase in acquired resistance to the Src inhibitor dasatinib. Upon acquisition of dasatinib resistance, the two RAS-mutant cell lines acquired the c-SRC gatekeeper mutation (T341M), whereas the two BRAF-mutant cell lines did not. Accordingly, Src signaling was refractory to dasatinib treatment in the RAS-mutant dasatinibresistant cell lines. Interestingly, activation of the MAPK pathway was increased in all four of the dasatinib-resistant cell lines, likely due to B-Raf and c-Raf dimerization. Furthermore, MAP2K1/MAP2K2 (MEK1/2) inhibition restored sensitivity in all four of the dasatinib-resistant cell lines, and overcame acquired resistance to dasatinib in the RAS-mutant Cal62 cell line, in vivo. Together, these studies demonstrate that acquisition of the c-SRC gatekeeper mutation and MAPK pathway signaling play important roles in promoting resistance to the Src inhibitor dasatinib. We further demonstrate that up-front combined inhibition with dasatinib and MEK1/2 or ERK1/2 inhibitors drives synergistic inhibition of growth and induction of apoptosis, indicating that combined inhibition may overcome mechanisms of survival in response to single-agent inhibition.

Original languageEnglish
Pages (from-to)1952-1963
Number of pages12
JournalMolecular cancer therapeutics
Volume15
Issue number8
DOIs
Publication statusPublished - 2016 Aug

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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