Luteolin-treatment induces caspase 3, 8 and 9 activation in the presence of TNFα in HT29 cells.

<p>HT29 cells were treated with luteolin (100 µM) alone or in combination with TNFα (20 ng/ml) for 12 h. Cells were lysed, protein extracts (20 µg) were subjected to SDS-PAGE (13%) and caspase 3, 8 and 9 processing was evaluated by Western blot using specific antibodies for cleaved caspases 3, 8 and 9. Immunoreactive proteins were detected using the enhanced chemiluminescence (ECL) technique. Representative results of at least 3 independent experiments are shown (A). Cells were treated as described above for 12 and 24 h. Cells were lysed and caspase 3 activity was quantified using a fluorescence-based assay as described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0000596#s2" target="_blank">Method</a> section. Representative results of at least 3 independent experiments are shown (* p<0.01 versus TNFα alone at 24 h) (B).