Gene therapy of pancreatic cancer with green fluorescent protein and tumor necrosis factor-related apoptosis-inducing ligand fusion gene expression driven by a human telomerase reverse transcriptase promoter

Background: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in malignant cells but not in normal cells. Ad/g-TRAIL, an adenoviral vector in which expression of green fluorescent protein (GFP) and TRAIL is driven by a human telomerase reverse transcriptase promoter, has shown promise as a targeted antitumor agent. Methods: To investigate the effects of TRAIL gene therapy on pancreatic cancer, BxPC-3, MIA-PaCa-2, Panc-1, and ASPC-1 cells were treated with Ad/g-TRAIL. Transfection and protein expression were determined by using immunoblotting and identification of GFP with fluorescent microscopy and flow cytometry. Cell viability was determined by proliferation assay. Cell-cycle analysis and quantification of caspase-3 were used to identify apoptosis. The in vivo efficacy of Ad/g-TRAIL was characterized in a novel red fluorescent protein murine model of MIA-PaCa-2 pancreatic cancer. Results: Cells treated with Ad/g-TRAIL expressed GFP and exhibited apoptotic morphology within 2 days of treatment. Treatment with this vector in vitro resulted in less cell viability, increased caspase-3 activity, and a greater apoptotic fraction than treatment with controls. In vivo, treatment with Ad/g-TRAIL significantly suppressed tumor growth. Conclusions: TRAIL gene therapy induces apoptosis of pancreatic tumor cells both in vitro and in vivo and is a promising therapy in the treatment of pancreatic cancer.