Inhibition of COX-2 enhances the antitumor efficacy of AEE788 in colorectal cancer cells.

<p>A) EGF-driven cell proliferation was assayed in cells growing in the presence of EGF (100 ng/ml) and in the presence or absence of AEE788 (2.5 μM), celecoxib (10 μM) and NS-398 (10 μM). B) Analysis of cell cycle was performed by flow cytometry after 48 h of treatment with AEE788 (2.5 μM) and/or celecoxib (10 μM) of cells growing in the presence of EGF (100 ng/mL). C) Expression levels of cyclooxygenase-2 (COX-2) were analyzed by western-blot in whole cell extracts form Caco-2 and HCT-116 cells. Expression of β-actin is included as loading control. D) The phosphorylated and non-phosphorylated forms of EGFR, ERK 1/2 and Akt were detected by Western-blot using specific antibodies. Cells were grown in the presence of EGF (100 ng/mL) and treated with AEE788 (2.5 µM) and/or celecoxib (10 μM) for 6h. The expression level of -actin was included as loading control. The corresponding densitometric analysis is also shown. Data are means ± SEM of three independent experiments (*p <0.05, compared with the control; # p<0.05, compared with AEE788-treated cells).