Influence of nimesulide on cyclooxygenase 2 expression and cell proliferation and apoptosis in human lung adenocarcinoma cell line A549

Aim: To study the effects of nimesulide( NIM) on cyclooxygenase 2 ( COX-2 ) expression, cell proliferation and apoptosis in human lung adenocarcinoma cell line A549. Methods: A549 cells were treated with NIM (25 μmol/L, 50 μmol/L, 100 μmol/L, 200 μmol/L) for 48 h, the expressions of COX-2 mRNA and protein of A549 cells were evaluated by RT-PCR and Western blot, respectively; the cell cycle and apoptosis rate were analysed by flow cytometry. MTT reduction assay was used to evaluate the inhibitory rate of A549 cells treated by NIM for 24 h, 48 h, 72 h. Results:COX-2 mRNA and protein expressions of A549 cells were inhibited in a concentration dependent pattern by NIM ( r = - 0. 334 and -0. 923 , respectively ,P 0.01). NIM increased the proportion of cells in the G0/G1 phase and decreased the proportion in the S phase of the cell cycle, and induced A549 cells apoptosis in a concentration dependent pattern (r = 0. 994, P 0.01). The inhibitory rate of NIM on A549 cell proliferation increased as incubated time and NIM concentration increasing. Conclusion:The inhibitive effect of NIM on COX-2 expression may be an important cause of cell proliferation inhibition and apoptosis induction in human lung adenocarcinoma A549 cell line.