Fig. 4

MUFA/SFA ratio alteration induced by SCD1 inhibition leads to ER stress-mediated apoptosis. (A) PA-1 and SKOV-3 cells were treated with the IC50 value of CAY10566 for PA-1 cells (20 nM) for 48 h. Desaturase activity of SCD1 was estimated as the ratios of palmitoleic acid (C16:1n7) to palmitic acid (C16:0) and oleic acid (C18:1n9c) to stearic acid (C18:0) using gas chromatography. The statistical analysis was conducted using a two-way ANOVA followed by Šídák’s multiple comparisons test. (B) PA-1 cells were transfected with SCD1 siRNA (100 nM) or treated with CAY10566 (20 nM) for 48 h. The percentage of apoptotic cells was determined by flow cytometry analysis using Annexin V-FITC and PI staining. (C) PA-1 cells were transfected with SCD1 siRNA (100 nM) or treated with CAY10566 (20 nM) for 48 h. The expression levels of apoptosis marker proteins, PARP and cleaved caspase-3, were detected by western blot analysis. GAPDH was used as a loading control. (D) PA-1 cells were transfected with SCD1 siRNA (100 nM) or treated with CAY10566 (20 nM) for 48 h. The expression levels of ER stress marker proteins, p-PERK, IRE1α, ATF4, and CHOP, were examined by western blot analysis. GAPDH was used as a loading control. All data were described as mean ± SEM of three independent experiments (**p < 0.01; ***p < 0.001; ****p < 0.0001)