Fig. 5.

Treatment of cells with DHCB induced the expression of p53 and p21. A: Cells were treated with DHCB for 24 hours and the expression of p53 and p21 was determined by immunoblotting. B: p21 transcriptional analysis in HCT116 and Hke3 cells. Cells were transfected with the p21promoter reporter gene and were treated with DHCB as indicated for 18 hours. The luciferase and renilla activities were determined as described in Materials and Methods. C: HCT116 and HCT116 p53 ^−/− were treated with DHCB for 72 hours and immunoblotting was performed with antibodies specific for p53, gelsolin, p21 and tubulin. D: p21 transcriptional activity in HCT116 and in HCT116 p53^−/− cells. Cells were transfected with p21 promoter reporter plasmid and were treated with DHCB as indicated for 18 hours.