Figure 7.

Changes of regulatory molecules. (A) Induction of p21 by β-lapachone. Human DU145 prostate cancer cells were treated with various concentrations of β-lapachone for 4 h and further incubated with drug-free medium for 20 h. Total RNA was extracted, and Northern blotting was performed as described (15). p21 protein levels were determined by Western blotting (19). Lane 1, control; lane 2, 0.2 μM; lane 3, 1 μM; lane 4, 5 μM β-lapachone. (B) Changes of cyclins. Human prostate cancer cells (PC-3) were treated with β-lapachone and/or taxol as described above. Nuclear extracts were prepared. Cyclin-associated kinase activities were determined by immunoprecipitation as described (14). Lane 1, control cells; lane 2, 4 μM β-lapachone; lane 3, 0.02 μM taxol; lane 4, 4 μM β-lapachone plus 0.02 μM taxol; lane 5, control antibody.