<p>Supplementary Figure 1. Supplementary Figure S1. Dovitinib inhibits RET kinase and its downstream signaling in lung cancer cells harboring RET rearrangement A, Western blot analysis of indicated markers in LC-2/ad cells after treated with indicated dose of dovitinib for 4hr. B. Western blot analysis to measure the levels of total FGFR3, FLT3, RET, and KIT upon siRNA treatment in LC-2/ad cell line. Cells were transfected with indicated siRNA for 48hr.</p>
ARTICLE ABSTRACT
RET rearrangement is a newly identified oncogenic mutation in lung adenocarcinoma (LADC). Activity of dovitinib (TKI258), a potent inhibitor of FGFR, VEGFR, and PDGFR, in RET-rearranged LADC has not been reported. The aims of the study are to explore antitumor effects and mechanisms of acquired resistance of dovitinib in RET-rearranged LADC. Using structural modeling and in vitro analysis, we demonstrated that dovitinib induced cell-cycle arrest at G0–G1 phase and apoptosis by selective inhibition of RET kinase activity and ERK1/2 signaling in RET-rearranged LC-2/ad cells. Strong antitumor effect of dovitinib was observed in an LC-2/ad tumor xenograft model. To identify the acquired resistance mechanisms to dovitinib, LC-2/ad cells were exposed to increasing concentrations of dovitinib to generate LC-2/ad DR cells. Gene-set enrichment analysis of gene expression and phosphor-kinase revealed that Src, a central gene in focal adhesion, was activated in LC-2/ad DR cells. Saracatinib, an src kinase inhibitor, suppressed ERK1/2 phosphorylation and growth of LC-2/ad DR cells. Taken together, these findings suggest that dovitinib can be a potential therapeutic option for RET-rearranged LADC, in which acquired resistance to dovitinib can be overcome by targeting Src. Mol Cancer Ther; 14(10); 2238–48. ©2015 AACR.
