Cox-1 but not Cox-2 enzyme regulates LTα production in HRS cells. (A) Indomethacin treatment at 0.1 and 0.3 mM effectively reduced LTα production by KM-H2 cells. (B) KM-H2 cells treated with Celecoxib at 25, 50, and 75 μM showed minimum reduction in LTα production. (C) Viability of L929 cells exposed to C/S derived from KM-H2 cells treated simultaneously with 60 µM SP600125 (SP) and 0.3 mM Indomethacin (Indo) was not significantly improved compared with L929 cells incubated with C/S derived from KM-H2 cells treated with indomethacin alone. Lowest L929 cell viability was seen in the presence of C/S derived from untreated KM-H2 cells and KM-H2 cells treated with DMSO. Values shown are the mean ± SEM from 3 different experiments. *Significant difference compared with untreated (UT) KMH2 cells at P ≤ .05.