Figure 10.

ERK1/2 inhibition affects the expression of cell cycle regulatory proteins. HPAECs were treated with dimethylsulfoxide (DMSO) or 30 µM PD98059 (PD 30) for 24 h, after which whole-cell protein were extracted, and immunoblotting was performed using antibodies against the following proteins: cyclin A, cyclin D, Cdk4, p27, and β-actin. Representative immunoblots showing the expression of the above proteins (A). Densitometric analyses wherein cyclin A (B), cyclin D (C), Cdk4 (D), and p27 Kip 1 (E) band intensities were quantified and normalized to those of total β-actin. The values are presented as mean ± SD (n = 6/group). Significant differences between DMSO- and PD-treated cells are indicated by * p < 0.05 (t-test).