PTGS2 and colonic neoplasm: We observed a significant reduction in ROS production in IL1β-treated HT29 cells in the presence of the NOX1 inhibitor GKT137831 (GKT, 5 μM), confirming the importance of the NOX1 enzyme in redox balance dysregulation of colon cancer cells (Figure 5d).To better understand the correlation between COX2 induction and ROS production promoted by IL1β treatment, we performed a Western blot and PCR analysis of COX2 expression in the presence/absence of GKT (5 μM).