Research Article

Activations of Both Extrinsic and Intrinsic Pathways in HCT 116 Human Colorectal Cancer Cells Contribute to Apoptosis through p53-Mediated ATM/Fas Signaling by Emilia sonchifolia Extract, a Folklore Medicinal Plant

Figure 3

ESE affected the activities and protein levels of caspase-3, -8, and -9 in HCT 116 cells. Cells were treated with 50 μg/mL of ESE for 6, 12, and 24 h. (a) ESE stimulated the activities of caspase-3, caspase-8, and caspase-9 in HCT cells as described in Section 2. The values presented are the mean ± S.D. (n = 3) from three independent experiments. *** indicates a significant different when compared to control (0 h) sample. (b) The total proteins were harvested from ESE (50 μg/mL) treated HCT 116 cells for 0, 6, 12, and 24 h and determined the protein levels of pro-caspase-3, pro-caspase-8, and pro-caspase-9 by Western blotting. Actin was used as a loading control. (c) ESE stimulated the translocation of caspase-3 trafficking to nuclei in HCT 116 cells by confocal laser scanning microscope as described in Section 2. Cells were pre-incubated with or without specific inhibitors of caspase-3 (Z-DEVD-FMK), caspase-8 (Z-IETD-FMK), and caspase-9 (Z-LEHD-FMK), respectively, and then treated with ESE-(50 μg/mL) for 24 h. The cellular viability was assessed by MTT assay (d) and apoptotic cells were assessed by TUNEL assay and flow cytometric analysis (e). The values presented are the mean ± S.D. (n = 3) from three independent experiments. ***P < 0.001 shows a significant different when compared to ESE treatment.
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