Abstract
OBJECTIVE: To investigate whether sodium butyrate (NaB) and sorafenib synergistically induces ferroptosis to suppress proliferation of hepatocellular carcinoma cells and the possible underlying mechanisms. METHODS: CCK8 assay and colony formation assay were used to assess the effects of NaB and sorafenib, alone or in combination, on proliferation of HepG2 cells, and ferroptosis of the treated cells was detected with GSH assay and C11-BODIPY 581/591 fluorescent probe. TCGA database was used to analyze differential YAP gene expression between liver cancer and normal tissues. The effects of NaB and sorafenib on YAP and p-YAP expressions in HepG2 cells were invesitigated using Western blotting. RESULTS: NaB (2 mmol/L) significantly reduced the IC(50) of sorafenib in HepG2 cells, and combination index analysis confirmed the synergy between sorafenib and NaB. The ferroptosis inhibitor Fer-1 and the YAP activator (XMU) obviously reversed the growthinhibitory effects of the combined treatment with NaB and sorafenib in HepG2 cells. The combined treatment with NaB and sorafenib, as compared with the two agents used alone, significantly inhibited colony formation of HepG2 cells, further enhanced cellular shrinkage and dispersion, and decreased intracellular GSH and lipid ROS levels, and these effects were reversed by Fer-1 and XMU. TCGA analysis revealed a higher YAP mRNA expression in liver cancer tissues than in normal liver tissues. NaB combined with sorafenib produced significantly stronger effects than the individual agents for downregulating YAP protein expression and upregulating YAP phosphorylation level in HepG2 cells. CONCLUSION: NaB combined with sorafenib synergistically inhibit hepatocellular carcinoma cell proliferation possibly by inducing ferroptosis via inhibiting YAP expression.