Abstract: To investigate the effect of cyclooxygenase2 (Cox2) inhibitor on leukemia HL60 (human acute promylocytic leukeamia cell line) cells. Methods: HL60 cells in culture medium were treated with different concentrations of Cox2 inhibitor, Celecoxib in vitro. MTT assay was used to detect the cell inhibition effect, and flow cytometry (FCM) was used to explore the cell apoptosis. The morphology of cell apoptosis was observed by Hoechst 33258 staining, and the activity of Caspase3 was detected before and after apoptosis. Results: Celecoxib revealed significant antiproliferation and apoptosis inducing effects on HL60 cells in vitro, and the activity of Caspase3 was upregulated remarkably in time and dosedependent manner. Conclusion: Celecoxib has significant antiproliferation and apoptosis inducing effects on HL60 cells, which may closely relate to the increasing of Caspase

Key words: Cyclooxygenase2, Caspases3, Apoptosis