[Effect of Hypoxia on the Proliferation and Hypoxia Inducible Factor-1α Expression in Human Leukemia K562 Cells]

To explore the effect of hypoxia on the cell proliferation and expression of hypoxia-inducible factor-1α(HIF-1α) of human leukemia K562 cells.

The leukemia cells were divided into 2 groups: hypoxia-treated group and conventional oxygen group as control. The K562 cells in hypoxia-treated group were treated with 50, 200, 400 and 800 µmol/L of CoCl₂, while the K562 cells in control group were cultured in conventional oxygen condition, then the K562 cells in 2 groups were colleted after treatment for 24, 48 and 72 hours. The morphological changes of cells were observed by the inverted phase-contrast microscopy, the proliferation-inhibitory rates of cells was detected by MTT method, the expression of HIF-1α at transcription level was detected by real-time fluorescent quantitative PCR.

The cell morphology was changed with increase of CoCl₂ concentration and prolonging of treatment time of CoCl₂. The MTT assay showed that the inhibitory rate of cell proliferation was enhanced also with increase of CoCl₂ concentration and prolonging of treatment time of CoCl₂(r=0.435, r=0.389, P<0.05). The real-time fluorescent quantitative PCR showed that the mRNA expression of HIF-1α in K562 cells of hypoxia group was up-regulated in concentration- and time- dependant manners. and displayed the positive correlation with concentration of CoCl₂ and treatment time (r=0.954, r=0895).

The hypoxia can inhibit the proliferation of K562 cells and up-requlate the expression of HIF-1α in cells, but does not induce cell differentiation.