Objective      To investigate the inhibitory effect of thiostrepton (TST) on human nasopharyngeal carcinoma transplanted in nude mice through inhibiting forkhead box M1 (FoxM1) expression.       Methods      Human nasopharyngeal carcinoma cells CNE-2 were xenografted into nu

de mice

and then the tumor-bearing mice were randomly divided into control group and TST treatment group (200 μg/kg). The control group was treated with dimethyl sulfoxide (DMSO) solution

while the TST treatment group was administrated with DMSO solution containing TST by peritoneal injection. Tumor growth was observed

and the tumor was weighed to calculate tumor inhibitory rate. The apoptotic rate and cell cycle changes were analyzed by flow cytometry. Expression of FoxM1 protein and apoptosis associated proteins were detected by Western blotting.       Results      The mean tumor volume in the TST treatment group was significantly smaller than that in the control group (P0.05). The tumor was 0.582±0.172 g in the TST treatment group and 1.118±0.159 g in the control group

and the tumor inhibitory rate of the TST treatment group was 47.94% (P0.05). Flow cytometry indicated that the apoptotic rate [(16.99±1.75)%

]

and the percentage [(66.44±3.65)%

]

of G

1

-phase cells in the TST treatment group were significantly higher than those in the control group [（6.12±0.95)%

F=179.1

P0.01; (47.23±5.68)%

F=48.6

P0.01

]

. Western blotting showed that the expression of FoxM1 protein and apoptosis associated proteins (Cyclin D1 and Skp2) was decreased

but that of P27 protein was increased in the TST treatment group.       Conclusion      TST can effectively inhibit human nasopharyngeal carcinoma (CNE-2 cell line) transplanted in nude mice through down-regulating FoxM1 expression.