Fig. 7

ISRIB suppresses opioid-induced increase in CHOP and Bax expression. a Immunofluorescent analysis of CHOP (red) expression in MCF7 cells incubated with buffer, 2.5 µM or 25 µM DAMGO for 48 h. Blue is DAPI staining. Scale bar denotes 5 µm for all images. 2.5 µM DAMGO versus buffer, p < 0.05; 25 µM DAMGO versus buffer, p < 0.02; b MTT analysis of cells growing in the presence or absence of 2.5 µM or 25 µM DAMGO for 48 h. Graph represents mean values of delta(A₅₇₀ − A₆₃₀) (± SEM, n = 3). c Left panel, representative immunofluorescent images of CHOP (red) and Bax (green) in MCF7 cells incubated with buffer, 10 µM oxycodone, morphine or DAMGO and with or without 40 nM ISRIB. Scale bar denotes 5 µm for all images. Right panel, graphs representing mean fluorescent intensity of CHOP and Bax signals in MCF7 cells similar to experiments shown on the left panel. Red bars—CHOP; green bars—Bax. All data were normalized to buffer samples set as 1 (± SEM, n = 3). CHOP: oxycodone, morphine and DAMGO versus buffer, p < 0.01, p < 0.001, p < 0.001 respectively; oxycodone plus ISRIB versus oxycodone, p < 0.03; morphine plus ISRIB versus morphine, p < 0.008; DAMGO plus ISRIB versus DAMGO, p < 0.02. Bax: oxycodone, morphine and DAMGO versus buffer, p < 0.001 for all opioids; oxycodone plus ISRIB versus oxycodone, p < 0.04; morphine plus ISRIB versus morphine, p < 0.01; DAMGO plus ISRIB versus DAMGO, p < 0.04