Fig. 4
Induction of the tumor suppressor p53 and cyclin-CDK inhibitor p21(waf1/cip1) expression by FTS. 5 × 105 SW480 cells were plated on a 10-cm dish. After 20 hr and thereafter daily, media containing FTS (100 yM) or control solvent was added. Cells were harvested and immunoblotted for p53 and p21(waf1/cip1) protein levels after 4 days of treatment. Actin served as an internal control to demonstrate equal protein amounts in the respective lanes. Densitometric analysis showed a 1.6-fold induction of p53 expression and a 3.7-fold increase of p21(waf1/cip1) protein in FTS-treated cells.