Abstract:Objective ：To investigate the antitumor effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene transfection mediated by adenovirus into human pancreatic carcinoma cell line Panc-1, and the mechanisms involved in this effect. Methods ：TRAIL gene was transfected into pancreatic cancer cell line Panc-1 by an adenovirus vector (Ad-TRAIL). Level of TRAIL mRNA expression was determined using RT-PCR, and TRAIL protein synthesis was evaluated with Western blot. Cell-growth activities were determined by MTT assay. The bystander effect was observed by co-culturing the Panc-1 cells with and without the transfected TRAIL gene at different ratios. Apoptosis in pancreatic cancer cells was detected by flow cytometry. Proaspase-8 and procaspase-3 proteins were determined by Western blot. Results ：The stable overexpression of TRAIL was detected in Panc-1 cells transfected by Ad-TRAIL. Ad-TRAIL significantly inhibited cell viability of Panc-1 cells. Furthermore, co-culture of cancer cells transfected with TRAIL resulted in the nontransfected cell inhibition by bystander effect. Moreover, the percentage of apoptotic cells was significantly higher in the Ad-TRAIL-treatment group compared to the control groups ( P <0.01), and there was a diminished amount of procaspase-8 and procaspase-3 after infection with Ad-TRAIL transfection. Conclusions ：The overexpression of TRAIL gene in Panc-1 cells by Ad-TRAIL exerts a marked antitumor effect, and the mechanisms involved in this effect may be related to proapoptosis and bystander effect.