Involvement of both caspase-8 and Noxa-activated pathways in endoplasmic reticulum stress-induced apoptosis in triple-negative breast tumor cells

Apoptosis was measured after 3 days of treatment by subG1 analysis as described under Materials and methods section. Error bars represent standard error of the mean (SEM) from at least three independent experiments. *P？<？0.05; **P？<？0.01; ***P？<？0.001. A) Dose–response of thapsigargin (TG) in apoptosis in TNBC (red lines) and non-TNBC (blue lines) cells. B) Kinetics of apoptosis induction by TG (100？nM) in TNBC (MDA-MB231 and BT549) and non-TNBC (T47D) cell lines. C) MDA-MB231 and T47D were treated with TG (100？nM) for the indicates times. Kinetics of caspase processing and Bid loss were determined in whole-cell extracts by western blotting. Tubulin levels were used as protein-loading controls. D) Apoptosis was assessed in Bcl-XL-overexpressing MDA-MB231 cells treated with 100？nM TG or 1？μg/ml tunicamycin (TN). Bcl-XL expression was assessed by western blotting. Tubulin expression was used as a protein-loading contro