To investigate the proliferation and apoptosis of HepG2 cell under hypoxia induced by cobalt-chloride.

HepG2 cells were deal with CoCl₂ which was adopted to simulate low oxygen environment. The expression level of cytoplasmic protein Caspase 3 was measured by Western Blotting. The cell proliferation was detected by MTT assay. AnnexinV-FITC/PI double labeling staining and flow cytometry were used to test tumor cell apoptosis under oxygen deficiency with different CoCl₂ concentration.

The cytoplasmic Caspase 3 activity increased after low oxygen treatment, and expression suggested concentration-dependency, the same with the inhibition on the proliferative capabilities of HepG2 cells. Flow cytometry showed that the cell apoptosis rates of control group, the hypoxic groups of 50, 100, 200, 300, 500 μmol/L CoCl₂ were (0.42 ± 0.21)%, (1.22 ± 0.41)%, (7.61 ± 0.66)%, (13.31 ± 0.97)%, (20.41 ± 0.78)% and (28.56 ± 0.96)%.

Caspase-3 may play an important role in the development of liver cancers. Under hypoxic condition, it can regulate cell growth and differentiation. CoCl₂ inhibits the HepG2 cells proliferation and stimulates their apoptosis by up-regulating Caspase-3.