Abstract

In nasopharyngeal carcinoma (NPC), COX-2 inhibitors have been reported to exhibit dose-dependent growth inhibition of these cancer cells, but their interaction with radiation has not yet been studied.  Here, we examined the effects of selective COX-2 inhibitors SC-236 and NS-398 on the radiosensitivity of NPC cells.  When  incubated  with  COX-2  inhibitors  prior  to  irradiation,  increased  radiation  cell  kill was documented. However, when the sequence of COX-2 administration was reversed, we observed radioprotection instead. Our findings  hereby  confirmed  the  enhancement  effect  of  COX-2  inhibitors  on  radiation cell kill in vitro, but this effect is critically dependent on their  sequence of administration.     

Key words: Cyclooxygenase-2, inhibitors, nasopharyngeal carcinoma,  radiosen-sitization, radioprotection