5,7-Dihydroxyflavone Enhances the Apoptosis-Inducing Potential of TRAIL in Human Tumor Cells via Regulation of Apoptosis-Related Proteins

Figure 3

5,7-Dihydroxyflavone sensitized tumor cells to TRAIL-induced apoptosis. (A) HepG2 cells were treated with 5,7-dihydroxyflavone and/or TRAIL for 24 h. Apoptosis was assessed by propidium iodide DNA staining and flow cytometry. (B) HepG2, Jurkat or HeLa cells were treated with 5,7-dihydroxyflavone and/or TRAIL for 24 h. Apoptosis was assessed by hoechst33258 staining (×200) (HepG2 cells: a, control; b, 6 nM TRAIL; c, 20 μM 5,7-dihydroxyflavone; d, 60 nM TRAIL; e, 6 nM TRAIL + 20 μM 5,7-dihydroxyflavone; Jurkat and HeLa cells: a, control; b, 6 nM TRAIL; c, 20 μM 5,7-dihydroxyflavone; d, 6 nM TRAIL + 20 μM 5,7-dihydroxyflavone). (C) HepG2, Jurkat or HeLa cells were treated with 5,7-dihydroxyflavone and/or TRAIL for 24 h. Cell lysates were separated by SDS-PAGE, then procaspase-9, procaspase-3, and PARP proteins were detected by Western blot analysis. GADPH was used as loading control.