Inhibition of cytotoxicity of cisplatin by cyclooxygenase-2 inhibitor nimesulide in head and neck cancer cell lines.

Although head and neck cancer is a common malignancy, investigations have not yet improved the poor prognosis of patients. Therefore, it is important to find new cancer treatment modalities. Recent studies showed that cyclooxygenase, especially its isoform cyclooxygenase-2, is involved in tumorigenesis, tumor growth and metastasis. Inhibition of this enzyme by cyclooxygenase inhibitors has been shown to be antiproliferative in numerous cancer cell lines. The aim of this study was to investigate if the selective cyclooxygenase-2 inhibitor nimesulide could enhance cytotoxicity of the standard chemotherapeutic agent cisplatin. Head and neck squamous cell cancer cells were incubated with nimesulide and/or cisplatin, and counted after 24, 48 and 72 h treatment. Visualization of apoptotic cells was done by immunohistochemistry. We demonstrated that nimesulide inhibits the cytotoxic effect of cisplatin in HNSCC cells. Therefore, COX-2 inhibitor nimesulide may not be a good partner for cisplatin in combination therapy for cancer.