Cell cycle effects of the CTet in MCF-7 and MDA-MB-231 cell lines. DNA content profiles of cells that were exposed for 24 and 48 hours to 4 and 8 μM CTet or γ-cyclodextrin solution (CTR), stained with propidium iodide, and analyzed by flow cytometry are shown. Data are from one representative experiment. The percentages of cells in the different phases of the cell cycle are presented as the mean of three experiments ± standard error of the mean. Asterisks indicate statistically significant values with respect to CTR (one-way analysis of variance followed by Tukey post hoc test; P < 0.05). CTet, indole-3-carbinol cyclic tetrameric derivative.