RESUMO
<p><b>OBJECTIVE</b>To study the radiosensitizing effect of gefitinib on nasopharyngeal carcinoma cell line CNE2 in vitro.</p><p><b>METHODS</b>Nasopharyngeal carcinoma cell line CNE2 was cultured in RP2MI 1640. MTT assay was performed to evaluate the cell proliferation changes in response to gefitinib treatment and the radiosensitizing effect of gefitinib. The cell survival curves and sensitive enhancement ratio (SERs) were obtained with a clonogenic assay. Flow cytometry analysis was applied to detect the cell cycle changes and cell apoptosis.</p><p><b>RESULTS</b>MTT assay showed that cells exposed to gefitinib and radiation had a significantly lower survival ratio compared to the cells with radiation exposure only (0.582∓0.012 vs 0.398∓0.016, P=0.002), with a SER of 1.535∓0.134. The S phase cell percentage was significantly decreased and G(2)-M phase cells increased in gefitinib plus radiation group (P=0.000), suggesting a synergistic effect of gefitinib and radiation.</p><p><b>CONCLUSION</b>Gefitinib can enhance the radiosensitivity of nasopharyngeal carcinoma CNE2 cells in vitro possibly by inhibiting cell proliferation, inducing cell apoptosis, and causing changes in the cell cycle distribution.</p>