Figure 3.

Effect of in vivo inhibition of ERK1/2 phosphorylation using MEK-specific inhibitor, ARRY, attenuates TGF-α–induced lung cell proliferation and expression of matrix genes. Effect of ARRY on ERK (A) and Akt (B) phosphorylations. CCSP/- and CCSP/TGF-α mice on Dox for 4 days were cotreated with vehicle or ARRY (12.5 mg/kg twice daily). Total lung lysates were analyzed by immunoblotting. Treatment with ARRY inhibited pERK1/2, but had no effect on pAKT. For the gels illustrated in this figure, phosphorylated and total proteins were run on the same samples on separate gels under the same conditions and are combined for illustrative purposes. (C) Effect of ARRY on lung cell proliferation. CCSP/- and CCSP/TGF-α mice on Dox for 4 days were cotreated with vehicle or different doses of ARRY (12.5, 25, and 37.5 mg/kg twice daily). Proliferation was assessed at Day 4 using immunohistochemistry for the proliferation marker, Ki67. Data are percent of Ki67 cells per total lung cells in randomly counted lung fields. Data shown are mean values (±SEM). (D–F) Effect of ARRY on expression of extracellular matrix genes, col1a, col3a, and elastin. Real-time PCR analysis was performed in the lungs of CCSP/- and CCSP/TGF-α mice on Dox for 4 days and treated with vehicle or ARRY (37.5 mg/kg twice daily) for 4 days. The fold change was obtained by normalizing the gene expression number to those of HPRT, then comparing the samples to the CCSP/- mice treated with vehicle for 4 days. Data shown are mean values (±SEM) (n = 6–10/group). Statistical significance for data was measured using one-way ANOVA (n = 4–5/group).