Figure 2

Dose-effect analysis and the combination effect of tamoxifen and SCS. Dose-effect analysis was performed using 8.5-12.5 μg/ml SCS and 2.5-15 μM tamoxifen, for 24 h. Dose-effect curve of each agent alone for MCF-7 cells (A) and MDA-MB-231 cells (C) is representative of three independent experiments. EC₅₀ concentrations of SCS and 2.5-15 μM tamoxifen were used for combination effect analysis using the CalcuSyn program and normalized isobolograms for MCF-7 (B) and MDA-MB-231 (D) cells are shown. Diagonal line is the additivity line and data points below this line correspond to a synergistic effect. The concentration ratios between SCS and tamoxifen are indicated below the isobologram.