Fig. 1.

Effect of the model proteasome inhibitor MG132 on adrenocortical tumour cells. a, MG132 concentration dependent decrease of cell viability after 48 h. b, Influence of MG132 treatment on cortisol production. MG132 leads to a concentration and time dependent increase in CHOP mRNA c and XBP1 mRNA splicing d in NCI-H295R cells. e, Concentration dependent changes induced by MG132 treatment of NCI-H295 cells. M, molar concentration; CHOP, C/EBP homologous protein; eIF2α, eukaryotic translation initiation factor 2 A; P-eIF2α, phosphorylated eIF2α; HIF1α, hypoxia inducible factor 1; XBP1-s, X-Box binding protein 1, encoded by the spliced mRNA; GRP78, 78 kDa glucose-regulated protein; *, p < 0.05; **, p < 0.01; ***, p < 0.001 compared to reference treatment; experiments were performed in biological triplicates