Radiosensitization Of Celecoxib In Gastric Carcinoma Cell Line BGC823and Its Mechanism

Objective: To determine the radiosensitization by celecoxib, a selective cyclooxyg-enase-2(COX-2) inhibitor on human gastric carcinoma cell line BGC823and its possiblemechanism in vitro.Method: In order to measure proliferation inhibition of celecoxib and determine theconcentration IC50of celecoxib on cell line BGC823was investigated with MTT assay.The radio sensitization of celecoxib was measured by clongenic assay, and the survivalcurve was described; The following trial included a control group, celecoxibgroup(50μmol/L), radiation group(4Gy) and a combine group(drug+radiation). Cell cyclesin different groups were analyzed by flow cytometry (FCM); The expression of COX-2,VEGF were detected by RT-PCR.Result: The IC50of celecoxib treated with BGC823cells for24h was162.6μmol/L,for48h was95.4μmol/L, and for72h was62.1μmol/L. The D0, Dq, N and SF2values forirradiated BGC823cells pretreated with celecoxib were lower than those for unpretreatedones (1.705VS2.185,1.032VS2.327,1.832VS2.902,0.495VS0.745). The SER forirradiated BGC823cells pretreated with celecoxib was1.3. The result of the cell cycleshowed that BGC823cells arrest in G0/G1phase in the combination group. Celecoxibcombine with radiation inhibited expression of COX-2,VEGF (P＜0.05).Conclusion: The selective cyclooxygenase-2inhibitor, celecoxib enhanced radio-sensitization effect on human gastric carcinoma BGC823cells. The possible mechanismmay be involving repair inhibition of sublethal damage, redistribution of cell cycle andinhibit COX-2, VEGF mRNA expression.