Effect of echinomycin on the cell viability of PC12 cells after it inhibits hypoxia inducible factor-1α

Objective To clarify the role of hypoxia inducible factor(HIF)-1α in the process of hypoxia-induced cell death through inhibiting its transcription activity.Methods ① PC12 cells were seeded in the 12-well plate and treated for 24 h in normoxia(20% O2) or hypoxia(3% O2).Then photomicrographs under light microscope were taken and analyzed for situation of cell growth by cell-counting method.② PC12 cells were seeded in 96-well plate and treated for 24 h in 20% O2 or 3% O2.A test for cell survival called MTS was further used to detect the cell viability of PC12 cells.③ PC12 cells were treated with HIF-1α inhibitor-echinomycin for 24 h or 48 h at 5 nmol/L,50 nmol/L and 500 nmol/L,respectively.Then MTS was used to detect the cell viability.Results ① 3% O2 induced the death of PC12 cells significantly contrary to 20% O2.② Echinomycin administration eliminated the cell survival difference between 20% O2 and 3% O2 at 24 h.③ After a 48 h-treatment with echinomycin,it even reversed the hypoxia-enhanced cell death relative to normoxia.Conclusion Hypoxia could promote the death of PC 12 cells.After we used HIF-1α inhibitor echinomycin for 24 h,the death-promotion role of hypoxia was weakened.It even reversed the hypoxia-enhanced cell death after a 48 h-treatment with echinomycin.All these data suggested that the excessive transcription activation during hypoxia was detrimental to PC 12 cells.