索拉非尼因可阻断Raf信号等已成为晚期肝癌治疗一线药物，但其客观反应率仅41.6%，学者认为此与耐药有关。我们前期研究证实高Cryab表达肝癌细胞对其耐药(Hepatology,2013)；最近用激光显微切割后iTRAQ检测等发现KSR1在索拉非尼耐药肝癌组织与细胞系中表达显著高于非耐药组，且免疫组化/荧光显示p-KSR1核表达更为明显，这与p-KSR1通过影响胞浆Raf信号获得功能相饽。为此我们提出假说：KSR1通过Raf或磷酸化后核易位介导肝癌索拉非尼耐药。故我们通过检测肝癌组织KSR1与p-KSR1表达，明确其与索拉非尼耐药关系；调节肝癌KSR1表达，用免疫共沉淀结合质谱筛选、KEGG分析、pull-down及构建KSR1不同结构域质粒等探讨KSR1诱导索拉非尼耐药机制；体内验证。本研究将从KSR1不同亚细胞定位这个新视点揭示肝癌索拉非尼耐药机制，为索拉非尼耐药患者提供新治疗靶点。

Sorafenib has become the first-line drugs for advanced hepatocellular carcinoma due to blockage of Raf signal, but its objective response rate is only 41.6%, which is probably related to resistance. Our previous series of studies focused on the role of sorafenib in HCC and mechanisms of drug resistance. We found that HCC cells with high level of Cryab often expressed sorafenib resistance (Hepatology, 2013). Recently, we found that KSR1 expression in HCC tissues and cell lines with sorafenib resistance was significantly higher than that of non-resistance group using iTRAQ technology followed by laser capture microdissection,and p-KSR1 nuclear translocation using immunohistochemistry or immunocytochemistry. Existing theory about the role of KSR1 in Raf signal can not explain the reasons for resistance, and the role and mechanism of nuclear translocation of p-KSR1 is not clear.Therefore, we suppose that KSR1 mediate sorafenib resistance in HCC through Raf activation or neuclear translocation after phosphoration. Our aims are to detect expression of KSR1 and p-KSR1 in HCC tissues and analyze the relationship among their expression, progression of HCC and sorafenib resistance. After modification of KSR1 expression in HCC cells we investigate the biological function of HCC cells and the relationship between KSR1 expression and drug sorafenib. Combination co-immunoprecipitation and mass spectrometry, KEGG analysis and pull-down technology, we screen and verify its interacting protein. We construct different domains of plasmid of KSR1 and detect its functional domain. In vivo and in vitro experimental study are use to reveal the role of nuclear translocation of p-KSR1 and its mechanism. Above all, This study will further disclose the role and mechanism of KSR1 in HCC cells from new view of different subcellular location and provide a new target for HCC patients with sorafenib resistance.