Figure 6

Potential involvement of estrogen-mediated signaling on doxorubicin-induced Akt phosphorylation. (a) MCF7 cells grown to subconfluence were exposed to 1 μM ICI 182,780 (an estrogen receptor antagonist) or the vehicles (dimethyl sulfoxide [DMSO] and ethanol [EtOH]) for 30 min, and then treated with or without 10 nM estradiol (E2) for a further 30 min. Cell lysates were prepared for Western blot analysis with antibodies against Ser473-phosphorylated Akt (p-Akt) and total Akt. (b) MCF7 cells were cultured in regular 0.5% fetal bovine serum (FBS) medium, charcoal-stripped (CS) FBS medium, or regular 0.5% FBS plus 1 μM ICI 182,780. The cells were then treated with 0.25 to 1 μM doxorubicin (Doxo) for 24 hours. After treatment the cells were harvested, lysed and subjected to Western blot analyses with antibodies against p-Akt and total Akt.