The apoptosis of 293 cell induced by cadmium associated with the expression of Caspase-3 and p53

Objective To study the relationship between the apoptosis of 293 cell induced by cadmium and the expression of Caspase-3 and p53.Methods Transformed human embryonic kidney 293 cell line were incubated with 40 μmol/L CdCl2 for 0~24 hours. The cells in the groups of NAC and Z-DEVD-fmk pretreatment were treated with 5.0 mmol/L NAC and 0.1 μmol/L Z-DEVD-fmk before incubated with 40 μmol/L CdCl2. The expressions of Caspase-3 and p53 gene in 293 cell after treated with cadmium were determined by the methods of reverse transcription polymerase chain reaction (RT-PCR) and Western-blot analysis. And the occurrence of apoptosis was determined by flowcytometry. Results RT-PCR analysis revealed that incubated cells with 40 μmol/L cadmium 6~24 hours, the expression of Caspase-3 mRNA were increased obviously when compared with the controls. The pretreatment of NAC and Z-DEVD-fmk increased the expression of Caspase-3 mRNA compared with the cells with 40 μmol/L cadmium only. The expression of p53 mRNA had no changes between 0~24 hours incubated cells with 40 μmol/L cadmium. Western-blot analysis revealed that Caspase-3 20 000 u and p53 protein were increased 6 hours after cells incubated with 40 μmol/L cadmium. Pretreatment with NAC decreased the Caspase-3 20 000 u while pretreatment with Z-DEVD-fmk had no effects on it. Both NAC and Z-DEVD-fmk had no effects on the expression of p53 protein. Conclusion It was suggested that Caspase-3 could play a key role in cadmium-induced cell apoptosis.