Abstract 2839: Antitumor activities of FGFR inhibitors in FGFR1-overexpressing hepatocellular carcinoma patient-derived xenograft tumor models

Abstract

Abstract Hepatocellular carcinoma (HCC) is intrinsically resistant to conventional chemotherapies. Developing effective therapeutics becomes critical to tackle the unmet medical need. The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling axis plays an important role in liver development and homeostasis in adults. Deregulation of the FGF/FGFR signaling pathway through genetic modification or overexpression of the receptors (or their ligands) has been increasingly recognized in HCC. Accordingly, therapeutic intervention of the pathway has been extensively explored. In this study, analysis of a panel of patient-derived xenograft (PDX) HCC models by Affymetrix human gene expression arrays revealed overexpression of FGFR1 in 13 out of 43 (30%) models. Antitumor activities of FGFR inhibitors, including lenvatinib, dovitinib, ENMD-2076, and LY2874455, were then tested in five models. Lenvatinib exhibited the most potent activity in all models, whereas LY2874455 failed to show the effect in one of models. IC50s for FGFR1 inhibition of ENMD-2076, lenvatinib, dovitinib and LY2874455 were 145 nM, 134.5 nM, 53.5 nM and 0.6 nM, respectively. In SNU-16 and NCI-H520 cell lines, IC50s of dovitinib, lenvatinib, ENMD-2076, and LY2874455 were 76/1355 nM, 94/4770 nM, 306/2280 nM, and 0.3/664 nM, respectively. Furthermore, analyses of PDX tissues by Affymetrix SNP Array 6.0 arrays revealed no amplification of FGFR1/2 genes in four models except for amplifications of FGFR3 gene in two models. Whole exome sequencing did not detect nonsynonymous genetic alterations, including SNPs and indels, in FGFR1/2 genes in these xenografts except for a few genetic variations in FGFR3/4 genes. Overall, due to the multi-targeting mechanisms of these inhibitors, in vitro inhibitory effects of the compounds on FGFR1 enzyme and cell proliferation may not correlate with the in vivo anti-tumor activities. Overexpression of FGFR1 gene may serve as a predictive biomarker for therapeutic intervention of the FGF/FGFR pathway in HCC by using lenvatinib, dovitinib and ENMD-2076. Further studies are required to define additional biomarkers for LY2874455. Thus, our findings provide the rationale for the clinical development of FGFR inhibitors in a subset of HCC patients expressing a high level of FGFR1 gene. Citation Format: Douglas D. Fang, Bin Zhang, Weiguo Xu, Kang Yan, Qingyang Gu, Qiang Xu, Yexiong Tan, Hongye Sun, Qin Luo, Weifeng Mao, Chiho Li, Jiangpeng Liao, Guibai Liang, Shu-Hui Chen, Chi-Chung Chan. Antitumor activities of FGFR inhibitors in FGFR1-overexpressing hepatocellular carcinoma patient-derived xenograft tumor models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2839. doi:10.1158/1538-7445.AM2014-2839