Targeted inhibition of XIAP expression reverses resistance of colon cancer cells to TNF-related apoptosis-inducing ligand

Objective To study the resistance changes of colon cancer cells SW1116 to TNF-related apoptosis-inducing ligand ( TRAIL) after targeted inhibition of X-linked inhibitor of apoplosis protein (XIAP) expression by small hoop RNA plasmid. Methods Colon cancer cells were transfected by XIAP short hairpin RNA (shRNA) plasmid with liposorae. Inhibition rate and cell viability were examined 48 h post-transfection. SW1116 cells were exposed to TRAIL at concentrations of 25, 50, 100, 200 μLg/L, and their sensitivity to TRAIL was evaluated after inhibition of the XIAP expression. Caspase-3 activity in tumor cells was also evaluated by Western blotting. Results XIAP expression was decreased significantly after XIAP shRNA transfection (inhibition rate 60% ) , cell growing rate was inhibited (inhibition rate 24% ) , resistance to TRAIL was reversed, sensitivity to TRAIL was increased, cell growing inhibition rate reached 64% in 200 μg/L of TRAIL, and Caspase-3 activity was increased in tumor cells. Conclusion Targeted inhibition of XIAP expression restored and increased sensitivity of colon cancer cells to TRAIL. Key words: Colon carcinoma;  RNAi;  XIAP