Programmed cell death 4 enhances radiosensitivity of pancreatic cancer cells

Abstract

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. Key words: Pancreatic cancer; Radiosensitivity; Programmed cell death 4; β-catenin; c-myc