Data Availability StatementNot applicable. demonstrated that FGF19, when overexpressed, inhibited the effect of sorafenib on ROS generation and apoptosis in HCC. In contrast, loss of FGF19 or its receptor FGFR4 led to a impressive increase in sorafenib-induced ROS generation and apoptosis. In addition, knockdown of FGF19 in sorafenib-resistant HCC cells significantly enhanced the level of sensitivity to sorafenib. Importantly, focusing on FGF19/FGFR4 axis by ponatinib, a third-generation inhibitor of chronic myeloid leukemia, overcomes HCC resistance of sorafenib by enhancing ROS-associated apoptosis in sorafenib-treated SGK1-IN-1 HCC. Summary Our results provide the first evidence that inhibition of FGF19/FGFR4 signaling significantly overcomes sorafenib resistance in HCC. Co-treatment of ponatinib and sorafinib may represent an effective restorative approach for eradicating HCC. Electronic supplementary material The online version of this article (doi:10.1186/s13046-016-0478-9) contains supplementary material, which is available to authorized users. strong class=”kwd-title” Keywords: FGF19, FGFR4, Hepatocellular carcinoma, Drug resistance, Sorafenib, Synergistic effect Background Hepatocellular carcinoma (HCC) is the PEPCK-C sixth common malignancies worldwide and the third leading cause of cancer-associated mortality [1C5]. Although improvements in diagnostic techniques and instrumentation of oncology have improved the early analysis of HCC, the median survival of individuals with this disease is still low. Recently, a number of molecular targeted medicines have been illustrated to be promising providers in prolonging the overall survival of patients with advanced HCC. Particularly, as a multikinase inhibitor of Raf/MEK/ERK signaling and the receptor tyrosine kinases (RTKs), sorafenib leads to a survival benefit for patients through reducing tumor angiogenesis and increasing cancer cell apoptosis [6C9]. However, its use is often hampered by the occurrence of drug resistance [10C12]. Urgently needed to resolve the problem is to explore the mechanisms of resistance on sorafenib and seek an effective systemic therapy SGK1-IN-1 for patients after failure of sorafenib treatment. FGF19 is a metabolic regulator gene belonging to the hormone-like FGF family of signal molecules, and has activity as an ileum-derived postprandial hormone [13, 14]. Genomic and functional analyses SGK1-IN-1 show that FGF19 acts as an oncogenic driver in HCC [15C17]. FGFR4 is the predominant FGFR isoform in FGFRs in human hepatocytes and both FGF19 and FGFR4 are highly expressed in primary HCC . FGF19 has unique specificity for FGFR4 , and through binding to it, FGF19 activates different intracellular pathways, including GSK3/-catenin/E-cadherin signaling . Emerging studies indicate a focal, high-level amplification frequency of FGF19 in HCC clinical samples, which can be correlated with tumor size favorably, pathological stage and poor prognosis [15, 21C23]. Lately, HCC responder instances to sorafenib had been gathered to explore the association between your effectiveness of sorafenib and gene modifications . Using following era duplicate and sequencing quantity assay, an FGF19 duplicate quantity gain was recognized even more among full response instances than among non-complete response instances regularly, recommending FGF19 amplification may be a predictor of a reply to sorafenib . Therefore, improved knowledge of the medical relevance of FGF19 may bring molecular insights in to the treatment and pathogenesis of HCC. In this ongoing work, we established the need for FGF19 in sorafenib-induced cell viability, apoptosis, and build up of mitochondrial reactive oxidative varieties (ROS). We also examined the part of FGF19/FGFR4 and FGF19 axis in sorafenib level of resistance, and established the synergistic aftereffect of sorafenib and FGFR inhibitor ponatinib on sorafenib-resistant HCC cells. Our data reveal that FGF19 is vital for sorafenib level of resistance and effectiveness in the treating HCC. This research provides critical rationale to test the inhibition of FGF19 signaling in patients with sorafenib-resistant HCC. Methods Cell lines, reagents and standard assays HCC cell lines (MHCC97L, MHCC97H, HepG2, and SMMC7721) were directly obtained from American Type Culture Collection (ATCC, Rockville, MD). Sorafenib and ponatinib were purchased from Selleckchem (Houston, TX, USA). Superoxide dismutase (SOD), DMSO and DAPI were purchased from Sigma-Aldrich (St. Louis, MO). Standard cell culture, transient transfections, lentiviral transduction, quantitative RT-PCR (qRT-PCR), western blot, and cell viability assays were carried out as described previously . Antibodies and constructs Antibodies raised against FGF19 and FGFR4 were purchased from Abcam (Cambridge, MA), -actin was from Sigma-Aldrich (St Louis, MO), and cleaved PAPR (c-PARP) was from Cell Signaling (Beverly, MA). The full-length of human FGF19 and FGFR4 cDNA were cloned into pcDNA3.1(+) expression vector (Life technologies, Carlsbad, CA). Lentiviral vectors harboring shRNAs targeting.