GC induced signaling cascade of ERK1/2. Cells were incubated in the presence of 100nM DEX (GC) or medium (Co) for 12, 24, and 48 hours. Afterward, cells were lysed, and Western blot analysis was performed using antibodies against phosphorylated form of c-Raf, MEK1/2, ERK1/2, p90RSK, and total ERK1/2 (A). Cells were pretreated for 30 minutes in the presence of 10μM PP2, a selective inhibitor of src-family of tyrosine kinases, before stimulation with DEX (GC) or medium as a control (Co). After 16 hours of culture, cells were lysed, and immunoblotting was performed using anti-phospho ERK and total ERK antibodies (B). In parallel, cells were treated with 200nM STS (■) or left intact (□) for 6 hours. Apoptosis was assessed by determination of annexin V–positive cells (C) and cells with fragmented nuclei (D). The blots (A-B) presented are representative of 4 independent experiments. The plots (C-D) show mean ± SEM (n = 4).