ETS-1/c-Met drives resistance to sorafenib in hepatocellular carcinoma.

backgroundThe purpose of this study was to clarify the molecular regulatory mechanism of c-Met up-regulated expression and elucidate the molecular mechanisms by which c-Met overexpression and activation drive progression and sorafenib resistance in hepatocellular carcinoma (HCC).

methodsThe 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.

resultsc-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.

conclusionc-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.