FGFR2融合基因在肝癌索拉非尼获得性耐药中的作用及其分子机制

Sorafenib is the only FDA-approved first-line targeted drug for the treatment of advanced hepatocellular carcinoma. However, acquired drug resistance serves as the key restriction on effects of Sorafenib. Based on the successful establishment of the PDX (patient derived xenograft) model for sorafenib acquired resistance previously, we mapped evolution of acquired resistance-driven gene mutations of sorafenib under a new perspective of tumor evolution. We performed a multiple sites, integrated sequencing strategy in each generation of PDX tumor passage and found FGFR2-CCDC6 fusion gene as the driven gene for acquired sorafenib resistance. Preliminary results indicated that the potential mechanism for the acquired sorafenib resistance could be abnormal activation of MAPK signaling pathway by this fusion gene. Based on the previous data, we plan to screen the key molecules which are critical to MAPK signaling activated by FGFR2-CCDC6 fusion gene with genomics/proteomics method and further dig out the molecular regulation mechanism and its effect on acquired drug resistance. We will then study the effectiveness of reversing acquired drug resistance by targeting FGFR2-TK activity. We will also evaluate the method of forecasting acquired drug resistance by monitoring the dynamic changes of FGFR2-CCDC6 fusion ctDNA. Based on this study, we will demonstrate molecular mechanism of how FGFR2-CCDC6 fusion gene promote acquired drug resistance and provide novel, sensitive methods for the monitoring drug resistance in liver cancer. Present study will provide new strategy as well as approach for reversing acquired drug resistance in HCC，which has very important theoretical and clinical value.

索拉非尼目前是唯一用于晚期肝癌治疗一线靶向药物，获得性耐药是限制其疗效关键。我们在前期成功建立索拉非尼获得性耐药异种移植瘤模型(PDX)基础上，以肿瘤进化新视角绘制获得性耐药驱动基因变异进化图谱，对PDX连续传代过程中每代肿瘤进行多位点整合测序，筛选出FGFR2-CCDC6融合基因作为索拉非尼获得性耐药关键驱动基因，其潜在机制是MAPK信号通路异常激活。本研究拟在前期基础上，通过多组学技术深入探讨此融合基因激活MAPK通路驱动索拉非尼获得性耐药的机制；利用获得性耐药肝癌细胞系及PDX模型探索靶向FGFR2-TK活性对逆转获得性耐药的作用；最后通过监测其融合性ctDNA动态变化，评估其预警获得性耐药的价值。通过本研究可初步阐明FGFR2-CCDC6融合基因促进索拉非尼获得性耐药的分子机制并提出预警获得性耐药发生的敏感标志物，为逆转肝癌获得性耐药提供新策略和新方法，具有重要的理论与转化价值。

索拉非尼目前是用于晚期肝癌治疗一线靶向药物，获得性耐药是限制其疗效关键。本研究在成功建立索拉非尼获得性耐药异种移植瘤模型(PDX)基础上，以肿瘤进化新视角绘制获得性耐药驱动基因变异进化图谱，对PDX连续传代过程中每代肿瘤进行多位点整合测序，筛选出FGFR2-CCDC6融合基因作为索拉非尼获得性耐药关键驱动基因。我们通过免疫沉淀联合质谱对FGFR2-CCDC6融合蛋白具有相互作用的特异性蛋白质进行筛选并采用western blot进行验证后发现，FGFR2-CCDC6主要通过诱导MEK1发生磷酸化修饰结合，进而激活MEK1，从而产生ERK信号，最终促进索拉非尼耐药的产生。本研究拟在前期基础上，通过多组学技术深入探讨此融合基因激活MAPK通路驱动索拉非尼获得性耐药的机制。通过FISH检测根治性切除术后接受索拉非尼治疗的肝癌患者FGFR2-CCDC6融合基因的表达情况，发现索拉非尼敏感与耐药组之间FGFR2-CCDC6融合基因阳性患者较阴性患者总体生存时间显著缩短。最后，我们成功制备特异性靶向FGFR2-CCDC6融合基因的中和抗体，该抗体可逆转肝癌细胞系及PDX模型对索拉非尼的耐药。本研究初步阐明FGFR2-CCDC6融合基因促进索拉非尼获得性耐药的分子机制并提出预警获得性耐药发生的敏感标志物，为逆转肝癌获得性耐药提供新策略和新方法，具有重要的理论与转化价值。