Figure 1.
5,5′-DibromoDIM inhibits colon cancer cell proliferation and induces p21. Decreased proliferation of RKO (A) and HT-29 (B) cells. Cells were treated with DMSO or 5,5′-dibromoDIM (5, 10, or 15 μmol/L) for 24, 48, or 72 h, and cells were counted as described in Materials and Methods. The percent survival of treated cells was compared with DMSO (set at 100%). Mean ± SD of three determinations for each treatment. *, P < 0.05, significantly decreased survival. C, cell cycle progression. RKO cells were treated with DMSO or 15 μmol/L 5,5′-dibromoDIM for 24 h and analyzed by fluorescence-activated cell sorting as described in Materials and Methods. Mean ± SD of three determinations. *, significant 5,5′-dibromoDIM-induced changes. D, induction of p21 protein. RKO and HT-29 cells were treated with DMSO and different concentrations of 5,5′-dibromoDIM for 24 h, and p21 expression was determined by Western blot analysis as described in Materials and Methods.