Li, Fang, Li, Xiaoyan, Ruddy, David, Tam, Angela, Rakiec, Daniel, Battalagine, Linda, Schlegel, Robert, Monahan, John and Huang, Alan (2015) FGFR-Mediated Reactivation of MAPK Signaling Attenuates Antitumor Effects of Imatinib in Gastrointestinal Stromal Tumors. Cancer Discovery.

Abstract

Activating mutations in either KIT or PDGFRA are present in approximately 90% of gastrointestinal stromal tumors (GISTs). Although treatment with the KIT and PDGFR inhibitor imatinib can control advanced disease in about 80% of GIST patients, the beneficial effect is not durable. Here, we report that ligands from the FGF family reduced the effectiveness of imatinib in GIST cells, and FGF2 and FGFR1 are highly expressed in all primary GIST samples examined. The combination of KIT and FGFR inhibition showed increased growth inhibition in imatinib-sensitive GIST cell lines in the presence or absence of added FGF2. In addition, inhibition of mitogen-activated protein kinase (MAPK) signaling by imatinib was not sustained in GIST cells. An extracellular signal-regulated kinase (ERK) rebound occurred through activation of FGF signaling, and was repressed by FGFR inhibition. Downregultation of Sprouty proteins played a role in the imatinib-induced feedback activation of FGF signaling in GIST cells.

Item Type:	Article
Date Deposited:	02 May 2016 23:45
Last Modified:	02 May 2016 23:45
URI:	https://oak.novartis.com/id/eprint/21812