OBJECTIVETo investigate the role of COX-2 inhibitor celecoxib in enhancing the lethal effects of bleomycin in Tca8113 cell line.

METHODSTca8113 cells were treated with different concentrations of celecoxib and bleomycin for 24, 48, 72 h. Methyl thiazolyl tetrazolium assay was used to calculate cell growth inhibition rate and Jin Zheng Jun's method was used to evaluate the interaction of celecoxib and bleomycin on Tca8113 cells. Flow cytometry was used to evaluate the effects of combined use of celecoxib and bleomycin on cell cycle progress and apoptosis.

RESULTSLow dose of celecoxib (10 micromol/L, < IC(50)) combined with bleomycin showed synergism or additive lethal effect on Tca8113 cell line. Celecoxib could notably enhance the inhibitory effect of bleomycin on Tca8113 cells by blocking cell cycle progress and thus resulting in the increasing G(0)/G(1) cells [(60.93 +/- 0.32)%] distribution and inducing apoptosis [(1.87 +/- 0.11)%].

CONCLUSIONSLow doses of celecoxib could significantly enhance the lethal effect of bleomycin on Tca8113 cells by inhibiting cell growth and proliferation through blocking cell cycle progress and inducing apoptosis. The ways of these interactions on inhibiting Tca8113 cell growth were synergistic or/and additive.