Activation of the caspase-dependent apoptotic pathway by lasiodin.

<p>(<b>A</b>), After treatment with lasiodin for 24 hr, both the adherent and floating cells were collected and stained with Annexin V-FITC and propidium iodide (PI). The apoptotic ratio was calculated in terms of the FITC-positive values of the cells. The apoptotic ratio was represented by the relative percentages of the FITC-positive cells versus the DMSO-treated cells (vehicle control). (<b>B</b>), CNE1 and CNE2 cells were treated with lasiodin at the doses of 0.8, 3.1, and 6.3 µM. After 24 hr treatment, the expressions of caspase-3, caspase-9, PARP, Bax, and Bcl-2 were determined, and the cleavage products of caspase-9, caspase-3, and PARP were detected by Western blotting. NPC cells treated with the vehicle control (DMSO) were used as the reference group. GAPDH was used as the control for sample loading. (<b>C</b>), CNE1 and CNE2 cells were treated with lasiodin at 6.3 µM. After 24 hr treatment, the releases of Cyto-C and Apaf-1 were determined by immunofluorescence imaging analysis to monitor the Cyto-C and Apaf-1 releases from inter-mitochondrial space into cytosol. NPC cells treated with the vehicle control (DMSO) were used as the reference group. The figures are representative of three experiments. The data are presented as mean ± S.D. of three separate experiments. * <i>P</i><0.05, the significant differences between treatment and control groups.