Fig. 4

Tg-induced caspase activation requires PERK, ATF4 and CHOP, whereas Tg-mediated upregulation DR5 and LC3B protein levels depends on individual contributions from ATF4 and CHOP, but not PERK. a LNCaP cells were transfected for 2 d with the indicated siRNAs (siCtrl = non-targeting control siRNA), employing two different siRNA oligoes for each target (designated by − 1 and − 2). After 30 h of treatment with 100 nM Tg or 0.02% DMSO vehicle control (also transfected with siCtrl), whole cell lysates were prepared and subjected to western blotting with the indicated antibodies; Casp3 = caspase-3 (only cleaved caspase-3 bands are shown), cl-PARP = cleaved PARP. The positions of molecular weight markers are indicated to the left. The shift towards the slower migrating PERK band in Tg-treated cells reflects induction of PERK phosphorylation by Tg. One representative blot out of at least 3 independent experiments. b-g Quantifications of western blots from a, normalized to the tubulin loading control and then to the siCtrl+Tg condition. Mean ± SEM from 4 (b-d, f, and g) or 3 (e) independent experiments. Dots represent individual values, with a separate colour for each experiment. *P < 0.05, **P < 0.01, ***P < 0.001, ns; not significant, One-way ANOVA compared to the Tg + siCtrl condition