Abstract. Hepatocellular carcinoma remains one of the most prevalent malignancies worldwide. Curcuma aromatica and Polygonum cuspidatum are one of the commonly used pairedherbs for liver cancer treatment. Curcumin and resveratrol are the major anticancer constituents of Curcuma aromatica and Polygonum cuspidatum, respectively. Curcumin and resveratrol have been found to exhibit a synergistic anticancer effect in colon cancer. However, the combined effect of curcumin and resveratrol against hepatocellular carcinoma remains unknown. In the present study, we evaluated the combined effects of curcumin and resveratrol in hepatocellular carcinoma Hepa1-6 cells. The results showed that curcumin and resveratrol significantly inhibited the proliferation of Hepa1-6 cells in a dose-and time-dependent manner. The combination treatment of curcumin and resveratrol elicited a synergistic antiproliferative effect in Hepa1-6 cells. The apoptosis of Hepa1-6 cells induced by the combination treatment with curcumin and resveratrol was accompanied by caspase-3, -8 and -9 activation, which was completely abrogated by a pan caspase inhibitor, Z-VAD-FMK. Combination of curcumin and resveratrol upregulated intracellular reactive oxygen species (ROS) levels in Hepa1-6 cells. The ROS scavenger, NAC, partially attenuated the apoptosis and caspase activation induced by the combination treatment of curcumin and resveratrol. In addition, the combination of curcumin and resveratrol downregulated XIAP and survivin expression. These data suggest that the combination treatment of curcumin and resveratrol is a promising novel anticancer strategy for liver cancer. The present study also provides new insights into the effective mechanism of paired-herbs in Traditional Chinese Medicine.
IntroductionLiver cancer is the fifth most prevalent malignancy in men and the seventh in women worldwide (1). The incidence of liver cancer is increasing possibly due to the epidemic of obesity and the rise in hepatitis C virus infection (1). Current treatment for liver cancer includes surgical resection, liver transplantation, local ablation, transarterial chemoembolization and radioembolization, and targeted molecular therapy (2,3). Despite improved therapeutic methods, the curative outcome of advanced liver cancer patients remains elusive. Liver cancer remains the second leading cause of cancer-related death in men and the sixth in women (1). The overall 5-year survival rate of liver cancer patients has remained below 12% in the United States (3). Thus, there is a great need to develop novel agents or alternative strategy to treat liver cancer.In China, Traditional Chinese Medicine (TCM) has played a positive role in liver cancer treatment (4). Based on varied syndromes, different therapeutic methods and Chinese herbs can be employed to ameliorate clinical symptoms and local disease focus. Yujin (Curcuma aromatica) is a commonly used Chinese herb for treating liver cancer with blood-stasis and depressed liver-Qi with or without jaundice. Curcuma aromatica possesse...