Role of inhibitor of apoptosis proteins in TRAIL-induced apoptosis of gastric cancer cells

Aim To explore the role of inhibitor of apoptosis proteins(IAP) in regulating the sensitivity of gastric cancer cells to tumor necrosis factor-related apoptosis-inducing ligand(TRAIL)-induced apoptosis.Methods Apoptotic cells were determined by the propidium iodide method using flow cytometry.The activation of caspase-3 and PARP cleavage were conducted by Western blot analysis.Expressions of XIAP,Survivin,cIAP1 and cIAP2 before and after treatment with TRAIL were also measured by Western blot analysis.Results TRAIL induced apoptosis in gastric cancer cells.BGC-823 cells were more sensitive to TRAIL than SGC-7901 cells.Caspse-3 activation and PARP cleavage were detected early after exposure to TRAIL.IAP family members were constitutively overexpressed in the two cell lines.The expression of XIAP was significantly downregulated in BGC-823 cells,compared with that in SGC-7901 cells,after TRAIL treatment.The expression of Survivin and cIAP1 remained unchanged.The expression of cIAP2 was slightly lowered in the two cell lines.Conclusions TRAIL-induced apoptosis of gastric cancer cells appears to be determined at the level of the effector caspase-3.XIAP protects gastric cancer cells from TRAIL-indued apoptosis.