Figure 5

Effects of expression level of Skp2 or p27Kip1 on salinomycin-induced G1 cell cycle arrest and cell growth inhibition. (a) DXR cells were transfected with si-Cont, Skp2, or p27Kip1. After 24 h of transfection, cells were treated without or with 4 μM salinomycin for 24 h, and equal amounts of cell lysates were subjected to immunoblot analysis using the indicated antibodies. (b) DXR cells were transfected with siRNA and then treated with salinomycin as in panel a, and cell cycle was analyzed by flow cytometer. The percentage of cells in G1 phase is annotated in each column. Data are presented as averages of triplicate measurements, with error bars representing standard deviations. These experiments were performed three times with comparable results. (c) MCF-7, SK-BR-3, and MDA-MB-468 cells were treated with 0–4 μM salinomycin for 24 h, and equal amounts of cell lysates were subjected to immunoblot analysis using the indicated antibodies. (d) MCF-7, SK-BR-3, and MDA-MB-468 cells were treated with 0–2 μM salinomycin for 72 h, and cell survival was determined by MTS assay. Data are presented as averages of triplicate measurements, with error bars representing standard deviations. These experiments were performed three times with comparable results. *P<0.05, **P<0.005, and ***P<0.0005. (e) A549 cells were treated without or with 4 μM salinomycin for 24 h, and equal amounts of cell lysates were subjected to immunoblot analysis using the indicated antibodies (upper panel). A549 cells were treated with 0–8 μM salinomycin for 72 h, and cell survival was determined by MTS assay (lower panel). Data are presented as averages of triplicate measurements, with error bars representing standard deviations. These experiments were performed three times with comparable results **P<0.005 and ***P<0.0005