Synergistic effect of CGS16949A and 5-fluorouracil on a human breast cancer cell line

The effects of the aromatase inhibitor, CGS16949A, and the fluoropyrimidine, 5-fluorouracil (5-FU), on cell cycle distribution and growth were studied using FACS analysis and MTT assay in the human breast cancer cell line, SK-BR-3. CGS16949A induced an increase in the G0-G1 fraction on SK-BR-3 cells, and the growth inhibition rate of the combination of both (65.7 +/- 3.0%) was significantly higher than 10 nM CGS16949A (37.9 +/- 6.9%) or 100 microg/ml 5-FU (45.6 +/- 4.5%); p < 0.01). Administering 5-FU after preincubation with CGS16949A significantly increased the combined cytotoxic efficacy, suggesting that clinical therapy using this combined therapy may be more efficient.