Fig. 2.

Doxorubicin induces early activation of ERK1/2 (A) and p53 (B) in H9c2 cells, beginning at 1 and 3 h of incubation, respectively. Cells were treated with 1 μM doxorubicin for the indicated times. Whole cell lysates were processed for Western blot analysis to detect changes in ERK1/2, phospho (p)-ERK1/2, p53, and p-p53. β-actin was used as an equal loading control. Representative Western blots are shown at left. The optical density is expressed in arbitrary units normalized against a control sample. Data in histograms represent means ± SE from 6 experiments. *P < 0.05, compared with control (0 h).