Figure 8
The induction of apoptosis from vesicular overexpressed in cancer prosurvival protein 1 (VOPP1) knockdown seen at 72 h post-siRNA transfection is abrogated with the use of the thiol-antioxidant N-acetyl cysteine (NAC) in a dose-dependent manner. (a) On the left axis, caspase-3/7 activity in arbitrary luminescence units is shown for control or VOPP1 siRNAs with or without 2.5 mM NAC in squamous cell carcinoma (SCC)-9 cells. These data are from an independent experiment conducted in quadruplicate for all conditions. On the right axis, the normalized data for the two VOPP1 small interfering (si)RNAs is re-plotted as percent caspase-3/7 activation relative to baseline (no NAC treatment). The asterisks denoted the significant decrease seen with both VOPP1 targeting siRNAs (P<10−4, bootstrap analysis), indicating that the thiol antioxidant NAC can abrogate the induction of apoptosis observed with VOPP1 knockdown 72 h post-transfection. (b) NAC is titrated from 2.5 mM down to zero and the percent caspase-3/7 activation, as in (a), is shown relative to control, no NAC. These data are from an independent experiment conducted in sextuplicate for all conditions shown in (b). The solid black line represents the linear regression of the trend observed in (b), with Pearson's correlation coefficient (r) and corresponding P-value of significance (P) shown. The abrogation of VOPP1 knockdown-induced apoptosis by NAC is dose responsive. All error bars in the figure represent the 95% confidence intervals.
