Fig. 6

ERK induces cell death through the induction of stress response. M238 cells were treated in triplicates with A. ISRIB (1 µM), an inhibitor of stress response induction, or B. Z-IETD-FMK (50 µM), a Caspase 8 inhibitor (Casp8i), in the presence or absence of IFNγ. Cells were stained on day 5 and imaged using the IncuCyte Zoom instrument to enumerate total DNA-containing objects (left panels) and those with caspase 3/7 activity. Caspase activity counts were normalized to the total DNA-containing object counts, and means were plotted in the right panels. Error bars indicate SEM. Results are representative of 3 and 2 independent experiments, respectively. Stable cell lines expressing shRNAs against GFP (control) and C. DR5, or D. NOXA, were treated with or without IFNγ in triplicate wells per condition. Cells were stained as in panel A on day 5 of treatment, and mean values for cell growth (left) and cell death (right) were plotted for each condition. Error bars indicate SEM. Results are representative of 3 independent experiments. Statistically significant differences in cell death as compared to the IFNγ-treated sample (panels A and B) and shGFP plus IFNγ sample (panels C and D) are indicated by an asterisk: * P < 0.05, ** P < 0.01. See also Fig. S14