Fig. 6.

NOC reduced protein synthesis and increased P-eIF2α levels, whereas ST-401 only induced such responses transiently. a, b Changes in the expression of mRNA coding for the cytosolic ribosomal machinery after 8 (a) and 24 h (b) treatment with NOC (100 nM) and ST-401 (100 nM). The x-axis represents the normalized effect size (normalized β coefficient) relative to vehicle (CTR) in response to treatment. c, d Change in the expression of mRNAs involved in the ISR following 8 h and 24 h treatments with NOC (100 nM) (c) or ST-401 (100 nM) (d). The x-axis represents the normalized effect size (β coefficient) relative to vehicle (CTR) in response to treatment. Statistics (a–d) Gray zone shows filtered for significance (from − 0.2 to 0.2). e–f Western blot analysis of puromycin staining of protein in CTR, NOC (100 nM) and ST-401 (100 nM) treated cells (e) and its quantification normalized by the total amount of protein using Ponceau staining (Additional file 1: Fig. S6a). Statistics (e, f): Data are expressed as means of 3 independent experiments. Ordinary one-way ANOVA analysis (followed by Tuckey). *P < 0.05 and **P < 0.01 significantly different from corresponding CTR. g Western blot analysis (top) and quantification (bottom) of P-eIF2α levels normalized by total amount of protein using Ponceau staining (Additional file 1: Fig. S6b). Statistics (g): Data are expressed as means of 3 independent experiments. Ordinary one-way ANOVA analysis (followed by Dunnett’s). *P < 0.05 and **P < 0.01 significantly different from corresponding CTR. h Stress granules labeled with G3BP1 and visualized by fluorescence microscopy. Representative images of HCT116 cells treated for 24 h with vehicle (DMSO 0.1%, CTR), NOC (100 nM) or ST-401 (100 nM) and stained with G3BP1 to visualize stress granules. Positive control: NaAsO₂ (500 µM). Scale bar = 10 µM