Knockdown of B-cell lymphoma-extra large (Bcl-xL) enhances the effect of glycogen synthase kinase 3 β (GSK-3β) inhibitor on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. HuH-7 cells were divided into five groups of cells treated with: a, Blank control; b, Ad5.TRAIL and short hairpin (sh)Bcl-xL; c, Ad5.TRAIL and sh cellular inhibitor of apoptosis protein 2 (cIAP2); d, Ad5.TRAIL, shBcl-xL and GSK-3β inhibitor; and e, Ad5.TRAIL, shcIAP2 and GSK-3β inhibitor. (A) Detection of apoptotic HuH-7 cells by flow cytometric assay. (B) Apoptosis index demonstrating that the apoptosis of cells treated with Ad5.TRAIL, shBcl-xL and GSK-3β inhibitor were significantly enhanced. **P<0.05. PI, propidium iodide.