Effects of TNF-related apoptosis-inducing ligand on cell apoptosis of pancreatic cancer

Objective To investigate the mechanism of TNF-related apoptosis-inducing ligand (TRAIL) promoting apoptosis of pancreatic cancer cells SW1990, Patu8988 and BxPC3. Methods Three kinds of pancreatic cancer cells SW1990, Patu8988 and BxPC3 were transfected with the pCA13 plasmid carrying TRAIL gene (pCA13 TRAIL group) and the blank plasmid control (pCA13 group), respectively. The expression of TRAIL mRNA in transfected cells was detected by RT-PCR, and the expression of TRAIL protein was detected by Western blot. The apoptosis rate and expression of TRAIL receptor R1 and R2 were detected by flow cytometry. Apoptosis was detected by TUNEL and Hoechst double staining, and observed by electron microscopy. The expression of caspase-3 in transfected cells was detected by immunohistochemistry. Results SW1990, Patu8988 and BxPC3 cells can expresse TRAIL mRNA and protein within 24 h after transfection. The apoptotic rate at 24 h after transfection was (27.30±5.14)%, (13.52±0.95)% and (31.40±8.70)%, respectively, which was higher than that of pCA13 group [(10.58±1.88)%, (8.42±0.46)% and (16.11±1.66)%], respectively. The expression rates of TRAIL-R1 were (61.37±3.05)%, (42.10±5.11)% and (36.64±4.84)%, respectively, and the expression rates of TRAIL-R2 were (36.20±4.83)%, (37.26±8.46)% and (24.32±3.71)%, respectively, which were higher than those of pCA13 group except PATU8988 cells. Positivity rates of caspase-3 were(14.64±5.35)%, (9.92±5.50)% and (16.12±6.74)%, which were obviously higher than(3.01±1.50)%, (1.75±0.50)% and (3.79±1.58)% in pCA13 group, and the differences were statistically significant(P<0.05). Conclusions TRAIL could up-regulate the expression of TRAIL R1 and R2 in multiple pancreatic cancer cell lines in vitro, and thus promote cell apoptosis. Key words: Pancreatic neoplasms; Receptors, TNF-related apoptosis-inducing ligand; Apoptosis