Oncotarget

Research Papers:

FGFR signaling maintains a drug persistent cell population following epithelial-mesenchymal transition

Wells S. Brown, Saeed Salehin Akhand, Michael K. Wendt _

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Abstract

Wells S. Brown1, Saeed Salehin Akhand1, Michael K. Wendt1

1Purdue University Center for Cancer Research, Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, USA

Correspondence to:

Michael K. Wendt, email: mwendt@purdue.edu

Keywords: breast cancer, Her2 resistance, FGFR, EMT, covalent kinase inhibitor

Received: August 25, 2016     Accepted: October 13, 2016     Published: November 04, 2016

ABSTRACT

An emerging characteristic of drug resistance in cancer is the induction of epithelial-mesenchymal transition (EMT). However, the mechanisms of EMT-mediated drug resistance remain poorly defined. Therefore, we conducted long-term treatments of human epidermal growth factor receptor-2 (Her2)-transformed breast cancer cells with either the EGFR/Her2 kinase inhibitor, Lapatinib or TGF-β, a known physiological inducer of EMT. Both of these treatment regimes resulted in robust EMT phenotypes, but upon withdrawal a subpopulation of TGF-β induced cells readily underwent mesenchymal-epithelial transition, where as Lapatinib-induced cells failed to reestablish an epithelial population. The mesenchymal population that remained following TGF-β stimulation and withdrawal was quickly selected for during subsequent Lapatinib treatment, manifesting in inherent drug resistance. The Nanostring cancer progression gene panel revealed a dramatic upregulation of fibroblast growth factor receptor 1 (FGFR1) and its cognate ligand FGF2 in both acquired and inherent resistance. Mechanistically, FGF:Erk1/2 signaling functions to stabilize the EMT transcription factor Twist and thus maintain the mesenchymal and drug resistant phenotype. Finally, Lapatinib resistant cells could be readily eliminated using recently characterized covalent inhibitors of FGFR. Overall our data demonstrate that next-generation targeting of FGFR can be used in combination with Her2-targeted therapies to overcome resistance in this breast cancer subtype.

Author Information

Wells S. Brown

Saeed Salehin Akhand

Michael K. Wendt
Primary Contact  _


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