Fig. 8

Oxycodone activates the integrated stress response in MCF7 cells. Western blot analysis of phosphorylated and total eIF2α, ATF4, BiP, hsp70, and actin in MCF7 cell lysates treated with water and vehicle (None), 10 μM naloxone and vehicle (Nx), water and 5 μM oxycodone (Oxy) or combination of 10 μM naloxone and 5 μM oxycodone (Oxy + Nx). Left the representative images of western blots of corresponding proteins. Right graphs of the densitometric analysis of western blots. The graphs represent the mean ratio of signal of phosphorylated to total eIF2α, and ATF4, BiP, and hsp70 to actin obtained from three individual experiments using separate cell cultures. “Oxy”, “Nx”, and “Oxy + Nx” data were normalized to the “None” value set as one (±SEM). To determine statistical significance, data was analyzed by Student’s t test: Oxy vs None: P-eIF2α, BiP, ATF4, and hsp70, p < 0.05. Nx vs None: BiP, p < 0.001. Oxy ± Nx vs Oxy: P-eIF2α, p < 0.05; BiP, ATF4, and hsp70, p > 0.18