Fig. 4.

Effect of salubrinal, PERK or IRE1 inhibitor on the UPR and cell viability in HepG2 cells. Cells were subjected to hypoxia or tunicamycin as indicated for 48 h. a Effect on UPR marker mRNA expression by a PERK inhibitor and by an IRE1 inhibitor compared with solvent-treated cells under the same condition. b Immunoblotting for UPR markers. c Cell viability of HepG2 cells was assessed by a WST-1 assay. d Caspase-3 activity of HepG2 cells treated with the indicated compounds. These experiments were repeated six times with similar results. *p < 0.05, ***p < 0.001