ERK1/2 signalling protects against apoptosis following endoplasmic reticulum stress but cannot provide long-term protection against BAX/BAK-independent cell death
Fig 5
The PERK inhibitor GSK2606414 exacerbates ER stress-induced apoptosis.
(A) HCT116 cells were pre-treated for 1 h with 100 nM GSK2606414 prior to addition of the indicated concentration of Tm for 48 h. Cells were fixed, stained with propidium iodide and the proportion of cells with sub-G1 DNA was measured by flow cytometry. Results shown are the means ± S.D. of 3 independent experiments each performed in technical triplicate. Statistics represent the results of two-way ANOVA and Bonferroni post-tests; ***, p < 0.001. (B) HCT116 cells were treated as in (A) for 6 h (top panel) or 24 h (bottom panel). Whole cell lysates were analysed by immunoblotting using the indicated antibodies following separation by SDS-PAGE. Results shown are representative of 3 independent experiments. (C) HCT116 and HCT116 BAK-/-, BAX-/- (DKO) cells were pre-treated for 1 h with 100 nM GSK2606414 (GSK) before 48 h treatment with 0.1 μg ml-1 Tm. Cells were fixed, stained with propidium iodide and the proportion of cells with sub-G1 DNA was measured by flow cytometry. (D) HCT116 cells were pre-treated for 1 h with 100nM GSK2606414 prior to addition of 0.1 μg ml-1 Tm and 10 μM QVD-oPh (QVD), as indicated, for 48 h. Cells were fixed, stained with propidium iodide and the proportion of cells with sub-G1 DNA was measured by flow cytometry. Results shown in (C) and (D) are the means ± S.D. of 3 independent experiments performed in technical triplicate. Statistics represent the results of Student’s unpaired t-tests; **, p < 0.01.