Effects of small molecule inhibitors of p27 depletion (SMIPs) in prostate cancer cell lines. (a) Prostate cancer cell lines, LNCaP, PC3 and DU145 as well as HeLa and IMR90 cells were treated with vehicle (dimethyl sulfoxide; DMSO), SMIPs (40 μM) or the proteasome inhibitors, MG132 (M, 20 μM) and bortezomib (B, 100 nM) for 24 h. The levels of the indicated proteins were evaluated by immunoblotting. Asterisks denote an unspecific band. (b) The indicated cell lines were grown in soft agar and treated with vehicle (DMSO), SMIPs (40 μM), or bortezomib (100 nM) with addition of fresh compounds in three-day intervals as described in the Methods section. The images are representative of two independent experiments.