Figure 2.

Dox activates cell signaling proteins and survival factors in HMESO and H2373 cells. Western blot analysis was performed using specific antibodies for each cell signaling protein. Activation of extracellular signal-regulated kinase (ERK)1, ERK2, ERK5, and cyclic AMP response element binding protein (CREB) was determined after treatment with 1, 5, and 25 μM Dox for 24 hours in HMESO cells (A–E) and in H2373 cells (F–J). Data are expressed as the ratio of phosphorylated to unphosphorylated levels of proteins. *P ≤ 0.05 as compared with control (0) (n = 2 per group/experiment). pCREB, phosphorylated CREB; pERK, phosphorylated ERK.