Aim: To evaluate the therapeutic efficiency of Tumor Necrosis Factor-related Apoptosis-inducing Ligand (TRAIL) gene on human colorectal cancer cell line HT29.
Methods: Human embryonal kidney cells transformed by introducing sheared fragments of Ad5 DNA (293 cell) were used for amplification of adenoviral vectors: Ad/GT-TRAIL,Ad/GT-Bax, Ad/GT-LacZ and Ad/PGK-GV16. Human colorectal cancer cell line HT29 was transfected with binary adenovirus-mediated TRAIL gene. Bax gene was used as positive control, LacZ gene was used as the vector control,and cells treated with PBS only were used as a mock control. The morphological changes, cell growth and apoptosis were measured by reversmicroscope, MTT method and flow cytometry.
Results: All adenoviral vectors titer determined by optical absorbency at A260nm were 1X10(10) viral particle/ml(vp/ml). Obviously morphological changes of HT29 cells were observed when infected with Ad/GT-TRAIL, and these changes were much more obviously when Ad/PGK-GV16 was coinfected. The cell suppression percentage and the percentage of apoptotic cells were 52.5 % and 16.5 % respectively when infected with Ad/GT-TRAIL alone, while combining with Ad/PGK-GV16, the growth of HT29 was suppressed by 85.2 % and the percentage of apoptotic cells was 35.9 %. It showed a significantly enhanced therapeutic efficiency with binary system (P<0.05).
Conclusion: A binary adenoviral vector system provides an effective approach to amplify viral vectors that express potentially toxic gene, TRAIL. Ad/GT-TRAIL showed a significantly enhanced therapeutic efficiency for HT29 when coinfected with Ad/PGK-GV16. Ad/GT-TRAIL could induce apoptosis of HT29 and inhibit its growth.