Western blot analysis of lamin B in extracts from control and treated cells. Cells were incubated for 5-days in 75 cm2 flasks with 500 nM (HCT-116), 7.1 μM (A-549) or 1.2 μM (MiAPaCa-2) RPR-130401. A blank was also prepared for each cell line. The number of cells at the time of cell lysis, was in the range 107. At the end of treatment, the flasks were rinsed twice with ice-cold PBS and cells lysed in PHEM buffer as described under Materials and Methods. An aliquot of each extract (20 μg total protein) was loaded in the wells of a 7.5% polyacrylamide gel and electrophoresis was performed under usual conditions with molecular weight standards, followed by transfer to a nitrocellulose membrane. The membrane was incubated with a mouse monoclonal antibody directed against human lamin B and revealed through chemiluminescence detection (see Materials and Methods).