Low-dose 5-fluorouracil sensitizes HepG2 cells to TRAIL through TRAIL receptor DR5 and survivin-dependent mechanisms.

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising candidate for cancer treatment due to its highly selective apoptosis-inducing action on tumour cells without harming normal cells. However, because of TRAIL resistance by some cancer cells, combined treatment with sensitizing agents is required to enhance the anticancer potential of TRAIL. In the present study, we investigated the sensitizing effect of 5-fluorouracil (5-FU) on TRAIL-induced apoptosis in TRAIL-resistant HepG2 hepatocarcinoma cells. The results show that 5-FU pretreatment could sensitize HepG2 cells to TRAIL-mediated apoptosis. The enhanced induction of cell death by the 5-FU/TRAIL combination was mediated by DR5 up-regulation and survivin down-regulation. Furthermore, this combination treatment significantly inhibited the growth of human xenografts in vivo. In conclusion, this study demonstrates that the combination of a sensitizing agent and TRAIL may be a novel and effective therapeutic regimen for treating human hepatocellular carcinoma.