α-Hederin Potentiates 5-FU Antitumor Activity in Human Colon Adenocarcinoma Cells

The aim of this study was to investigate the ability of a-hederin to improve the efficacy of widely prescribed 5-fluorouracil (5-FU) in a human colon adenocarcinoma model. Drug combinations of a-hederin and 5-FU using both fixed-concentration and combination index methods were performed in vitro in HT-29 cells. The results showed that alpha-hederin at sub-IC50 cytotoxic concentrations enhanced 5-FU cytotoxicity about 3.3-fold (p < 0.001). Simultaneous combination of alpha-hederin and 5-FU at their IC50 ratio showed either a synergistic effect at a moderate cytotoxic range (25% of cell growth inhibition) or an antagonistic effect at a high level of growth inhibition. The data indicate therefore that it is possible to optimize colorectal cancer cell sensitivity to 5-FU with a-hederin. Copyright (C) 2008 John Wiley & Sons, Ltd.