[Effect of MAPK/NF-kappaB signaling pathway on extracellular release of HMGB1 induced by hypoxia in laryngeal Hep-2 carcinoma cells].

OBJECTIVE: To investigate the extracellular release of high mobility group box 1 (HMGB1) in laryngeal Hep-2 carcinoma cells induced by hypoxia and its possible mechanism. METHOD: The changes of HMGB1 concentration in the culture medium as well as HMGB1 protein and mRNA expression in Hep-2 cells were investigated after the cells were cultured with 1% O2 for different durations. Inhibitory effects of MAPK pathway inhibitors (PD98059. SP600125, and SB202190) and nuclear NF-kappaB pathway inhibitor (PDTC) with various concentrations on extracellular HMGB1 release were observed in hypoxia-induced Hep-2 cells. The HMGB1 concentration and HMGB1 protein expression were measured by enzyme-linked immunosorbent assay (ELISA) and western blot, respectively. The HMGB1 mRNA expression was determined by real-time quantitative PCR(RT-PCR). RESULT: The HMGB1 concentration in the culture medium and the HMGB1 protein expression in Hep-2 cells increased after the cells were subjected to hypoxia culture for 12 h in a time-dependent manner. The level of HMGB1 mRNA expression in Hep-2 cells increased after the cells were induced by hypoxia for 6h PD98059 and SP600125 with 20 micromol/ L and PDTC with 50 mg/L partly inhibited extracellular release of HMGB1 in hypoxia-cultured Hcp-2 cells. CONCLUSION: Hypoxia induces laryngeal carcinoma cells to release HMGH1. which may be related to MAPK/NF-kappaB signaling pathway.