METHODS: The resistance index was calculated. Bioinformatic techniques were applied to predict the transcription factors that bind and their binding sites on the c-Met promoter. Chromatin immunoprecipitation assays were implemented to verify the prediction results. To determine the regulatory mechanisms and effects of c-Met on sorafenib resistance in HCC, c-Met expression and activation were down-regulated by siRNA and inhibitor in in vivo and vitro experiments, while a parental cell line (Huh-7) was transfected with the adenovirus that upregulated c-Met expression.
RESULTS: c-Met expression was increased in HCC sorafenib-resistant cells. Functional findings suggested that c-Met overexpression and activation drive HCC tumor progression and sorafenib resistance by promoting cell proliferation, migration, and stopping apoptosis. Molecular mechanism findings demonstrated that the MEK/ERK signaling pathway activated the expression and activity of ETS-1 mediated by p-ERK, which led to its binding to the c-Met gene promoter and upregulation of c-Met transcriptional expression. The activation of the HGF/c-Met pathway drives sorafenib resistance in HCC cells by activating the Ras/Raf/ERK and PI3K/Akt signaling pathways, which regulate biologic processes, including cell proliferation, migration and anti-apoptosis.
CONCLUSIONS: c-Met overexpression and activation is an essential mechanism of sorafenib resistance in HCC. Combination therapy of sorafenib plus c-Met inhibitor overcame the resistance of sorafenib-targeted therapy for HCC.
方法:计算抗性指数。应用生物信息学技术来预测结合的转录因子及其在c-Met启动子上的结合位点。实施染色质免疫沉淀测定以验证预测结果。探讨c-Met对肝癌患者索拉非尼耐药的调控机制和作用。在体内和体外实验中,siRNA和抑制剂下调c-Met的表达和激活,而亲本细胞系(Huh-7)用上调c-Met表达的腺病毒转染。
结果:c-Met表达在肝癌索拉非尼耐药细胞中增加。功能研究结果表明,c-Met过表达和激活通过促进细胞增殖驱动HCC肿瘤进展和索拉非尼耐药,迁移,停止细胞凋亡。分子机制研究表明,MEK/ERK信号通路激活了p-ERK介导的ETS-1的表达和活性,这导致其与c-Met基因启动子结合并上调c-Met转录表达。HGF/c-Met通路的激活通过激活Ras/Raf/ERK和PI3K/Akt信号通路驱动HCC细胞中的索拉非尼耐药,调节生物过程,包括细胞增殖,迁移和抗凋亡。
结论:c-Met过表达和激活是肝癌中索拉非尼耐药的重要机制。索拉非尼联合c-Met抑制剂的联合治疗克服了索拉非尼靶向治疗肝癌的耐药性。