The cyclooxygenase-2 inhibitor nimesulide, a nonsteroidal analgesic, decreases the effect of radiation therapy in head-and-neck cancer cells.
BACKGROUND
No data are available on the effects of the cyclooxygenase-2 (COX-2) inhibitor nimesulide in combination with irradiation on the survival of head-and-neck carcinoma cells.


METHODS
Two head-and-neck carcinoma cell lines (SCC9 and SCC25) were treated with nimesulide (50-600 microM) and irradiated concomitantly or sequentially. Early effects on cell survival were investigated by counting cell numbers, long-term effects by colony-forming assays. Cell-cycle effects were analyzed 24-72 h after treatment with nimesulide by flow cytometry.


RESULTS
Unexpectedly, nimesulide solely inhibited cell proliferation without affecting colony-forming ability. In addition, no evidence for a radiosensitizing effect of nimesulide in short-term assays was seen. Nimesulide alone had no effect on clonogenic survival alone or in combination with radiation.


CONCLUSIONS
Nimesulide differentially affects cell proliferation and clonogenic survival and may decrease the efficacy of radiotherapy. Short-term assays to assess tumor growth may not correctly predict the clinically relevant long-term effect of COX-2 inhibitors.
Department of Cranio-, Maxillofacial and Oral Surgery, Medical University of Vienna, Vienna, Austria.
Cornelia
C
Czembirek
Christina
C
Eder-Czembirek
Boban M
BM
Erovic
Dritan
D
Turhani
Andreas
A
Spittler
Edgar
E
Selzer
Richard
R
Pötter
Dietmar
D
Thurnher
D000700:Analgesics / Q000008:administration & dosage; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects* / Q000528:radiation effects*; D052246:Cyclooxygenase 2 Inhibitors / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D006258:Head and Neck Neoplasms / Q000188:drug therapy / Q000503:physiopathology / Q000532:radiotherapy; D006801:Humans; D011836:Radiation Tolerance / Q000187:drug effects*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*; D013256:Steroids; D013449:Sulfonamides / Q000008:administration & dosage*
D000700:Analgesics; D052246:Cyclooxygenase 2 Inhibitors; D013256:Steroids; D013449:Sulfonamides; C012655:nimesulide