Effect of MAPK/NF-κB signaling pathway on extracellular release of HMGB1induced by hypoxia in laryngeal Hep-2carcinoma cells

Objective:To investigate the extracellular release of high mobility group box 1(HMGB1)in laryngeal Hep-2carcinoma cells induced by hypoxia and its possible mechanism.Method:The changes of HMGB1concentration in the culture medium as well as HMGB1protein and mRNA expression in Hep-2cells were investigated after the cells were cultured with 1% O2for different durations.Inhibitory effects of MAPK pathway inhibitors(PD98059,SP600125,and SB202190)and nuclear NF-κB pathway inhibitor(PDTC)with various concentrations on extracellular HMGB1release were observed in hypoxia-induced Hep-2cells.The HMGB1concentration and HMGB1protein expression were measured by enzyme-linked immunosorbent assay(ELISA)and western blot,respectively.The HMGB1mRNA expression was determined by real-time quantitative PCR(RT-PCR).Result:The HMGB1concentration in the culture medium and the HMGB1protein expression in Hep-2cells increased after the cells were subjected to hypoxia culture for 12hin a time-dependent manner.The level of HMGB1mRNA expression in Hep-2cells increased after the cells were induced by hypoxia for 6hPD98059and SP600125with 20μmol/L and PDTC with 50mg/L partly inhibited extracellular release of HMGB1in hypoxia-cultured Hep-2cells.Conclusion:Hypoxia induces laryngeal carcinoma cells to release HMGB1,which may be related to MAPK/NF-κB signaling pathway.