ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effects of celecoxib combined with radiotherapy on apoptosis of CNE-2Z cell lines and the potential mechanisms.</p><p><b>METHODS</b>Four groups were used, a control, celecoxib (25 micromol/L celecoxib), irradiation (8 Gy X ray) and celecoxib plus irradiation. The radiosensitising effect was detected by clone formation experiment. Flow cytometry was used to detect the apoptosis rate of cells. The expressions of Bcl-2 and Bax were assessed by immunocytochemistry. Western blot was used to examine the expression of Caspase-3.</p><p><b>RESULTS</b>Celecoxib enhanced the radiosensitivity of CNE-2Z cells. In experimental group, the mean surviving fraction and the mean lethal dose of CNE-2Z cells were 0.50 and 2.36 respectively. Compared with the irradiated group, there was significant differences between the two groups (P < 0.01). Celecoxib combined with radiotherapy up-regulation the expression of Bax. The score of the expression of Bax in the control group and the experimental group were 1.221 +/- 0.116 and 2.758 +/- 0.256 respectively. Celecoxib combined with radiotherapy could inhibit the expression of the protein of Bcl-2. The score of the expression of Bcl-2 in the control group and the experimental group were 2.559 +/- 0.144 and 1.253 +/- 0.114 respectively, with significant differences (P < 0.01). Celecoxib combined with radiotherapy could increase the apoptosis rate of tumor cells with significant differences (F = 7.63, P < 0.01). Western blot showed that the expression of Caspase-3 was strengthened.</p><p><b>CONCLUSION</b>Celecoxib combined with radiotherapy could induce apoptosis and enhance the radiosensitivity of human nasopharyngeal carcinoma CNE-2Z cell lines.</p>