ABSTRACT
PURPOSE: In the present study the effects of amiloride on the growth of human gastric adenocarcinoma cell line, AGS cells were examined with or without the addition of 5-fluorouracil (5-FU) in vitro. MATERIALS AND METHODS: The growth of AGS cells was examined by counting number of cells on two and four days post-treatment with 50 micrometer, 100 micrometer, 200 micrometer, 400 micrometer, 800 micrometer, amiloride, and 0.1 microgram/ml, 0.3 microgram/ml 5-FU, after plating AGS cells into 6 well plates at a density of 10 x 10(4) cells/well. The reversibility of the effects of amiloride was examined on two to eight days post-treatment with 400 micrometer amiloride after seeding 2 x 10(4) cells/dish. Cell cycle analysis was performed after four day-treatment with 400 micrometer amiloride. RESULTS: Amiloride (50~800 micrometer) significantly inhibited the growth of AGS in a dose-dependent fashion (p<0.05). The inhibitory effect of amiloride on growth of AGS was reversible since removal of amiloride after 24 hours treatment led to resumption of rapid growth up to control levels. Amiloride combined with 5-FU markedly inhibited the growth of AGS in a dose-dependent fashion compared to that of amiloride or 5-FU alone (p<0.05). The fraction of S phase, G0-G1 phase and G2-M phase was 19.3%, 55.7%, 18.8%, in the amioride group (400 micrometer) and 43.9%, 37.4%, 25.1% in the control group, respectively, showing significantly higher G1 fraction in amiloride group compared to control. CONCLUSION: This is the first paper which reported that amiloride inhibited in vitro growth of human gastric adenocarcinoma cells and that its effect of growth inhibition may be synergistic with 5-FU. Amiloride given with or without 5-FU may be useful agent in the treatment of gastric carcinomas. The inhibitory effects of amiloride on the growth of AGS may be mediated in part by blocking G1-S transition of cell cycle.