Abstract: ObjectiveTo explore effects of celecoxib on proliferation,apoptosis and VEGF expression in acute promyelocytic leukemia cell (NB4). Methods After acute promyelocytic leukemia cell line NB4 was treated by different concentrations of celecoxib,cell proliferation was detected by MTT assay.NB4 cell cycle distribution and apoptosis were measured by flow cytometry.Apoptosis related protein,the Bcl-2 expression and VEGF,HIF-1α mRNA levels were detected by Western blot and RT-PCR,respectively. Results The proliferation of NB4 cells was significantly inhibited by celecoxib.Celecoxib could increase the percentage of G₀/G₁ cells and decrease S phase cells.The rate of apoptosis cell was increased in NB4 cells with 20-80 μmol/L celecoxib treatment for 24h.Celecoxib significantly induced apoptosis,and down-regulated Bcl-2 protein (P＜0.05).VEGF and HIF-1α mRNA levels were inhibited in NB4 cells after celecoxib treatment. Conclusion Celecoxib could inhibit cell proliferation,arrest cycles and induce apoptosis,through down-regulation of VEGF and HIF-1α in acute promyelocytic leukemia cells in vitro.