[en] Objective: To investigate the effect and mechanism of programmed cell death 4 (PDCD4) on radiosensitivity of pancreatic cancer cells. Methods: Pancreatic cancer tissues and corresponding adjacent tissues were collected, the expression level of PDCD4 was detected by RT-PCR and Western blot. Human pancreatic cancer cells Sw1990 were transfected with PDCD4 overexpression vector (group pIRES2-PDCD4), empty vector (pIRES2 group), and treated with transfection reagent, respectively. The expression level of PDCD4 was detected by RT-PCR and Western blot. After radiation treatment, cell apoptosis was detected by flow cytometry, cell survival was detected by clone assay, and the expression levels of β-catenin, c-myc and Cleaved Caspase-3 were detected by Western blot. Results: The expression of PDCD4 mRNA and protein in pancreatic cancer tissues was significantly lower than that in adjacent tissues (t = 4.869, 9.208, P < 0.05). The expression of PDCD4 mRNA and protein in pIRES2-PDCD4 group was significantly lower than that in the non-transfection group (t = 9.074, 18.927, P < 0.05). After radiation, the apoptosis rate and Cleaved Caspase-3 level in the pIRES2-PDCD4 group were significantly higher than those in the non-transfection group (t = 3.670, 4.086, P < 0.05), while the expression levels of β-catenin and c-myc in the cells were significantly lower than those in the non-transfection group (t = 9.242, 17.644, P < 0.05). The radiosensitivity of pIRES2-PDCD4 group was higher than that of non-transfection group, and the sensitization ratio was 1.843. Conclusions: PDCD4 can increase radiosensitivity and promote apoptosis of pancreatic cancer cells, to which the Wnt signaling pathway may be related. (authors)