Effects of nimesulide on proliferation in leukemia K562 cells

Aim: To explore the effects of nimesulide, a selective COX-2 inhibitor, on the proliferation and apoptosis in leukemia K562 cells. Methods: Cell viability, cell cycle and the apoptosis of K562 were determined by MTT assay, flow cytometry and DNA ladder analysis. K562 cells were separately treated with different dosages of nimesulide (25, 50, 100 (μg·mL~(-1))) in vitro. Results: The cell proliferation was inhibited significantly by nimesulide, in a dose-dependent manner. At the middle dosage group (50 μg·mL~(-1)), the inhibitive effect of nimesulide was greater than that of adriamycin (25 μg·mL~(-1)). After exposure to different concentrations of nimesulide for 48 h, nimesulide elicited proapoptotic effects, and K562 cells were accumulated in G_0/G_1 phase, decreased in the number of cells in S phase. Its proapoptotic effect was also in a dose-dependent manner (from low to high dosage, the apoptotic rates were 3.4±2.8, 16.8±1.8 and 42.7±2.5 percent, respectively). The DNA ladder analysis further verified the proapototic effects of nimesulide. Conclusion: Nimesulide significantly inhibits the proliferation of K562 cell in vitro, and it may exert this proliferation-inhibiting action via inducing apoptosis and blocking cell cycle progression.