Figure 1.

(a) Effect of NS‐398 (10 µm) treatment for 24 h on COX‐2 expression in HT29, HCA7 and HCT116 cell lines. Lysates of 2 × 10⁶ cells from untreated (C) and NS‐398 treated (NS) cultures were resolved by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis and were probed with anti‐COX‐2 monoclonal antibody (72 kDa). Protein levels were determined by Western immunoblotting. Blots were re‐probed with anti‐α‐tubulin to confirm equal loading. (b) Effect of NS‐398 (5 and 10 µm) on apoptosis in colorectal cancer cell lines. Results expressed as percentage of apoptotic cells (annexin V, positive/7‐amino‐actinomycin, negative). NS‐398 treatment did not increase the percentage of apoptotic cells. Values are expressed as mean (SEM) from three different experiments. (c) Inhibition of PGE₂ secretion by NS‐398 treatment. HT29, HCA7 and HCT116 colonic carcinoma cell lines were treated with solvent, control and 5 or 10 µm of NS‐398 for 24 h. NS‐398 significantly reduced PGE₂ levels in HT29 and HCA7 cells. Data shown are results of duplicate measurements.