[Inhibitory effect of genistein on hypoxia-inducible factor-1alpha expression induced by cobalt chloride in leukemia cell line K562].

This study was aimed to investigate the effect of genistein (gen) on the expression of hypoxia inducible factor-1alpha (HIF-1alpha) induced by cobalt chloride (CoCl(2)) in human leukemia cell line K562. The hypoxia condition was simulated by CoCl(2); the dose- and time-effect groups were prepared as follows: the former were exposed to 0, 50, 100 and 150 micromol/L of CoCl(2) for 72 hours, the latter were detected at 0, 24, 48 and 72 hours while treated with CoCl(2) 100 micromol/L. The gen-treated samples were divided into five groups: (1) normal control; (2) CoCl(2) 150 micromol/L; (3) CoCl(2) 150 micromol/L + gen 50 micromol/L; (4) CoCl(2) 150 micromol/L + gen 100 micromol/L; (5) CoCl(2) 150 micromol/L + gen 200 micromol/L. The HIF-1alpha mRNA and protein were detected by RT-PCR and Western blot respectively. The results indicated that the expression of HIF-1alpha protein in K562 cells induced by CoCl(2) increased in dose-and time-dependent manner (p<0.01), while the expression of HIF-1alpha mRNA in K562 cell remained the similar level (p>0.05). Gen significantly inhibited the expression of HIF-1alpha protein induced by CoCl(2) in dose-dependent manner (p<0.01) while the HIF-1alpha mRNA expression was not affected by treatment of gen (p>0.05). It is concluded that CoCl(2) dose- and time-dependently induced the HIF-1alpha protein expression; HIF-1alpha mRNA was constantly expressed regardless of normoxic conditions or in the presence of cobalt ion under normoxic conditions. Gen can inhibit HIF-1alpha expression in K562 cell induced by CoCl(2) at level of protein, but not mRNA.