[Caspase-3 antisense oligodeoxynucleotides inhibit caspase-3 expression and apoptosis of gamma-irradiated HL-60 cells].

It has been shown that gamma -irradiation induces apoptosis of the human promyeloid leukemia cell line HL-60, but the mechanism remains unclear. To explore the effect of caspase-3 in this apoptotic model, antisense oligodeoxynucleotides (ASODNs) targeting 5'-noncoding region (ASODN-1) and initial translation region (ASODN-2) of caspase-3 mRNA were designed, synthesized and introduced into HL-60 cells by means of liposome-mediated transfection followed by gamma-irradiation in the present study. The TUNEL assay was used for morphological analysis of HL-60 cell apoptosis. Immunocytochemical staining, Western blotting and RT-PCR were, respectively, performed for detecting expression of caspase-3 and its mRNA. HL-60 cells transfected with mismatched oligodeoxynucleotide (MODN) or untransfected were taken as the control groups. The TUNEL assay showed that the percentages of HL-60 cell apoptosis induced by gamma-Irradiation in both ASODN-1 and ASODN-2 groups were significantly reduced compared with those in the control group (P<0.01) when the final transfection concentration was > or = 3 micromol/L. Immunocytochemistry demonstrated that in the ASODN-1 and ASODN-2 groups, caspase-3 positive cell percentages were reduced and average gray values of the positive cells increased significantly compared with those in the control group (P<0.01). Western blotting found that procaspase-3 expression in HL-60 cells of the ASODNs groups was decreased,and it was lower in the ASODN-1 group than in the ASODN-2 group. RT-PCR revealed marked expression of caspase-3 mRNA in HL-60 cells of the control group. Expression of caspase-3 mRNA was decreased after ASODNs transfection. Furthermore, ASODN-1 was more effective in inhibiting HL-60 cell apoptosis (P<0.05) and caspase-3 expression (P<0.01) than ASODN-2. These results indicate that caspase-3 mRNA ASODNs prevent HL-60 cells from apoptosis induced by gamma-radiation,and reduce expression of caspase-3 and its mRNA. These effects are dose dependent in a certain range.