Objective:To explore the effect of inhibiting c-raf-1 by antisense technology on radiosensitivity in human cervical carcinoma cell line HeLa.Methods:There were four groups in the study:control group

lipofectin group

sense oligodexynucleotides(S-ODN) group

antisense oligodexynucleotides(AS-ODN) group.The expression of c-raf-1 was detected by means of RT-PCR

Cellular response to irradiation was evaluated by the colony forming test

Apoptosis was observed by fluorescent staining.Bcl-2 protein expression was determined by flow cytometry.Results:AS-ODN group could significantly decreased the proliferation rate and increasing the apoptosis rate

significantly downregulating the expression of Bcl-2 of irradiated human cervical carcinoma cells

(vs lipofectin group or S-ODN group

P<0.01).Conclusion:c-raf-1 antisense oligodexynucleotides sensitized the HeLa to ionizing irradiation through decreasing the expression of c-raf-1

which might be related to inhibiting the celluar radiation-resistant signal transduction pathway and increasing the apoptosis rate of HeLa cells.