Figure 4.

Dose response of sulindac sulfone inhibition of EGFR. HT29 cells were grown to 80% confluence in medium containing 10% FBS then serum deprived for 24 h before addition of drug. Cells were then treated with vehicle (0.2% DMSO), 200, 400, 600, or 800 μM sulindac sulfone, drug doses previously shown to induce apoptotic cell death in these cells. Twenty four hours after drug treatment, vehicle or 10 ng/ml EGF was added and cells were harvested 10 min later. (A) Immunoblots were performed on cell lysates with antibodies raised against pEGFR (pY1068), total EGFR, pERK1/2, total ERK1/2, and caspase-3; total ERK1/2 immunoblots served as loading controls. The graphs show the densitometry results of the pEGFR bands (B) and total EGFR bands (C). Results shown in figure are representative of 3 separate experiments.