Anti-tumor effects of various interferons-alpha +5-fluorouracil via downregulation of dihydropyrimidine dehydrogenase in hepatoma cells

BACKGROUND AND AIMS: Systemic chemotherapy has not seen widespread use in the treatment for hepatocellular carcinoma (HCC). Recently, it was reported that combination treatment of 5-fluorouracil (5-FU) and interferon (IFN)-alpha was effective for non-resectable HCC. The effect of 5-FU treatment is influenced by the activities of pyrimidine catabolic enzymes. The aim of this study was to investigate which IFN-alphais most effective in combination therapy via downregulation of dihydropyrimidine dehydrogenase (DPD). METHODS: Cell proliferation assay in human hepatoma cells (HepG 2) was performed using 5-FU and/or various IFNs-alpha (C-IFN, Intron A, OIF). At the same time,DPD mRNA levels were quantified by real-time polymerase chain reaction. RESULTS: 5-FU alone but not all the IFNs showed anti-cancer effects, and the combination of each IFN +5-FU had a greater anti-cancer effect than 5-FU alone. C-IFN +5-FU most effectively prevented cancer cell proliferation (p < 0.05). Also, the combination of C-IFN +5-FU most downregulated DPD mRNA expression. CONCLUSION: The combination of each IFN-alpha +5-FU showed anti-cancer effects for HCC via downregulation of DPD. C-IFN may be most effective in the combination therapy of IFN-alpha +5-FU for HCC.