Fig. 6.

The effect of high-dose PDE inhibitors on proliferation/survival signaling in colon cancer cell lines. (A) LS174T and Caco2 colon cancer cells were treated with 200 µM Sildenafil (Sil), 100 µM PF-04447943 (PF), or 100 µM TAK-063 (TAK) for different times as indicated. The effects of treatment on ERK, AKT, and β-catenin were determined by immunoblotting. (B) Densitometric analysis of blots, where ratios of band intensities for ERK-P/ERK, AKT-P/AKT, and β-catenin/β-actin were calculated and expressed as a percent of the basal level (0 hour time point; dashed line).