COX2 inhibition or the gene silencing induced cell cycle arrest and cell growth suppression. (A) UMUC2 cells were treated by the selective COX2 inhibitor, CAY10404(CAY) or DuP-697(DuP) at the indicated concentrations for 48 h, then cell viability was assessed by MTS assay. (B) At 72 h after transfection of control or COX2 siRNA at 100 nM, cell viability and COX2/COX1 expression were analyzed by MTS assay and western blotting, respectively. Actin was used for internal positive control. (C) and (D) UMUC2 cells were transfected by control or COX2 siRNA, or treated by DMSO, CAY or DUP, then cell cycle analysis was performed by flow cytometry and p27 expression was examined by western blotting. Dimethyl sulfoxide was used as control reagent.