Figure 9

CHOP-mediated DR5 upregulation is critical for thapsigargin-stimulated TRAIL-induced apoptosis in ESCC cells.

(A) Viability is shown as OD values. (B) Apoptosis is shown as apoptotic index. (C) ROS concentrations are shown. (D) The intracellular Caspase 9 activity levels are shown. The two indexes in the control group were defined as 100%. (E) Representative Western blot results of the key proteins, including CHOP, p-AMPK, DR5, Caspase 9, Bcl2, and Bax are shown. Membranes were re-probed for β-actin expression to show that similar amounts of protein were loaded in each lane. (F) Schematic diagram of the DR5 promoter constructs used for the luciferase activity assay (top). ESCC cells were transfected with pDR5-605-WT or pDR5-605-mCHOP promoter constructs and β-gal plasmid and then treated with thapsigargin (1 μM) plus TRAIL (100 ng/ml) for 24 hours and cells were lysed for luciferase assay (EC109 as middle, TE12 as bottom). The results are expressed as the mean ± SD; n = 6. ^aP < 0.05 vs. the control siRNA group in EC109 cells, ^abP < 0.05 vs. the control siRNA group in TE12 cells.