Objective: To construct self-inactivating (SIN) lentiviral vector carrying human soluble tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) gene and to observe the effects of sTRAIL gene on apoptosis in SGC-7901 cells, so as to assess the value of sTRAIL in gene therapy for gastric cancer.
Methods: The bicistronic SIN lentiviral transfer plasmid containing sTRAIL gene and internal ribosomal entry site-green fluorescent protein gene (IRES-GFP) was constructed. Recombinant lentivirus containing sTRAIL were packaged using liposome by lentiviral packing system. Several cell lines including HL-7702, HLF-1 and SGC-7901 cells were infected with the viral supernatant. Flow cytometry was used to measure apoptosis of cells and recombinant sTRAIL. protein was assayed by ELISA at 24 h after infection.
Results: The lentiviral transfer plasmid pXZ208-sTRAIL was constructed, and the virus titres were above 10(6) IU/mL in the supernatant. SGC-7901 cells were efficiently infected by recombinant virus. The apoptosis rate of SGC-7901 cells was increased with the virus multiplicity of infection (MOI) increasing. When the MOI was > or = 0.5, a dose-dependent apoptosis rate was observed. At MOI of 6.0, the highest apoptosis rate (29.12 +/- 2.87)% was observed, while the expression of sTRAIL in the supernatant was only (34.08 +/- 3.43) ng/mL. However, no significant apoptosis was observed in HL-7702 cells and HLF-1 cells.
Conclusion: Recombinant lentivirus carrying human sTRAIL gene can efficiently infected SGC-7901 cells, which induced apoptosis in SGC-7901 cells in vitro by secreting bioactive sTRAIL protein. However, this effect is not seen in normal cells.