Growth inhibition and radiosensitivity enhancement of lung cancer cell line by a selective cyclooxygenase-2 inhibitor

Objective To investigate the growth,apoptosis and ra diosensitivity enhancement of lung cancer cell line A549 by a selective cyclooxy genase-2 inhibitor,celecoxib. Methods The effect of celecoxib on the survival of A549 tumor cells was measured by MTT, the cell cycle and apop tosis were measured using flow cytometric method(FCM). Radiosensitivity effect o f celecoxib on A549 cells was assayed by clonal survival. Results The inhibitory rate of 50μmol/L celecoxib dealing with A549 tumor cells in 24 and 72 hours were 4.27±1.33(%) and 10.63±2.23(%) respectively, 100μmol/ L were 33.47±8.02(%), 61.97±7.32(%),respectively. This effect was mainly in hibiting proliferation, leading to arrest of cells in G0/G1 phase and cell death when 100μmol/L dealing in 72 hours. Celecoxib did not induce any apoptosis i n A549 tumor cells or render tumor cells more susceptible to radiation-induced apoptosis. The cell clonal survival assay showed that celecoxib decreased the ca lculated survival fraction (SF) for all radiation doses, especially in high dose s. The survival fractions in 2 Gy radiation dose in contrast and dealing with 10 0μmol/L celecoxib 24 and 72 hours were 0.53±0.06, 0.52±0.11 and 0.46±0.05 ,respectively; The radiation enhancement ratios in dealing 24 and 72 hours were 1.27 and 1.7(a ratio of D 0 value),respectively. Conclusion C elecoxib siginificently inhibited the growth and proliferation of A549 tumor cel ls, this effect is time and dose dependent, leading to accumulation of tumor cel ls in G 0/G 1 phase; but can not induced apoptosis. Celecoxib enhances radiose nsitivity of A549 tumor cells and is time and the dose dependent. This effect is more efficient in high radiation dose.