GC7 blocks epithelial-mesenchymal transition and reverses hypoxia-induced chemotherapy resistance in hepatocellular carcinoma cells

Hypoxia is common in solid tumors and results in the activation of hypoxia-response genes. Hypoxia-inducible factor-1α (HIF-1α) is thought to reflect major cellular adaptation to hypoxia and contributes to chemoresistance in various tumors including hepatocellular carcinoma (HCC). N1-guanyl-1,7-diaminoheptane (GC7) is an inhibitor which suppresses the active eukaryotic translation initiation factor 5A-2 (eIF5A2), preventing epithelial-mesenchymal transition (EMT) in chemoresistance. In this study, we investigated the role of GC7 in the therapeutic effect of doxorubicin in hypoxia in HCC. We utilized four types of HCC cell line (Huh7, Hep3B, SNU387 and SNU449) in this study. Western blot and immunofluorescence were used to detect expression of epithelial/mesenchymal markers for EMT evaluation and HIF-1α was knocked down using HIF-1α-siRNA. Hypoxia-induced EMT contributed to doxorubicin chemoresistance in HCC cells. Low concentrations of GC7 sensitized Huh7 and Hep3B to doxorubicin by reversing EMT. Knockdown of HIF-1α attenuated hypoxia-induced EMT and abolished the unique feature of GC7. GC7 enhanced sensitivity to doxorubicin in HCC by reversing hypoxia-induced EMT via the HIF-1α-mediated signaling pathway. We suggest a new method of enhancing cytotoxicity of chemotherapy and improving the long-term survival rate in HCC.