Impact of salinomycin on caspase activation.

<p>Caspase activities were measured after treatment of breast and colon cancer cell lines with salinomycin for 28 hours. (<b>A</b>) Caspase 9 activity measured with Z-LEHD-aminoluciferin as a substrate; (<b>B</b>) Caspase 8 activity measured with Z-LETD-aminoluciferin as a substrate; (<b>C</b>) Caspase 3/7 activity measured in colon cancer cell lines with Z-DEVD-aminoluciferin as a substrate. Measurements were in MCF-7 cells were omitted as these cells are caspase 3-negative. Significant increases in measured luminescence in comparison to the untreated cells are indicated in the graphs (*: p<0.05; **: p<0.01, ***: p<0.001 by t-test). RKO cells were most sensitive to salinomycin treatment for all the measured caspases. (<b>D</b>) Western blot analysis of caspase status. Procaspase 3 and procaspase 9 expression were determined in SW480, SW620, RKO, and MCF-7 cells. β-Actin was used as a loading control. (<b>E</b>) Caspase 3 status in T47D and MDA-MB-453 cells. Procaspase 3 expression was determined by Western blot; α-Tubulin was used as a loading control. (<b>F</b>) Caspase 3/7 activity measured in breast cancer cell lines with Z-DEVD-aminoluciferin as a substrate. Caspase 3 activity was not measured in MCF-7 as these cells are caspase 3-negative.