Inhibitory Effects Of Cyclooxygenase-2 Selective Inhibitor Celecoxib On Human Endometrium Adenocarcinoma

Objective:To investigate the in-vitro and in-vivo inhibitory effect of Cyclooxygenase-2 selective inhibitor Celecoxib on human endometrium adenocarcinoma and the mechanism, providing theoretical basis for the treatment of human endometrium adenocarcinoma.Methods:1.The HEC-1B cells were treated with different concentrations of celecoxib(25-200umol/L)for different times,the cells proliferation was examined by MTT assay,the cell cycle and apoptosis were detected by flow cytometry,the change of cells ultramicrostructure were observed by transmission electron microscope,the cells invasiveness were detected by transwell chamber,the expression of COX-2 mRNA was analyzed by RT-PCR.2.Thirty nude mice were subcutaneously implanted with HEC-1B cells to establish human endometrium adenocarcinoma xenografts in nude mice. When the diameter of tumor was about 5mm,they were divided randomely into three groups,treated with normal sodium,low dose(2mg/d)of celecoxib and high dose(4mg/d) of celecoxib for two weeks.3.The volume of the tumors were calculated every 3 days and then describe the tumor growth curve;after finishing the treatment,the nude mice were killed and the weight of implanted tumors were measured,the tumor inhibition rates were calculated.The expression of COX-2 mRNA in tumor samples was analyzed by RT-PCR,the expression of COX-2 protein and microvessel density in tumor samples were examined by immunohistochemistry. Results:1.MTT results indicate that celecoxib can inhibit HEC-1B cells proliferation in a time- and dose-dependent manner, Flow cytometry results indicate that the cell percent of G0/G1 phase increases, and the cell percent of S and G2/M phase decreases, cell apoptosis rate also increases, there is significant difference contrast with control group(P<0.05).Transmission electron microscope results indicate that there are characteristic apoptosis changes in HEC-1B cells. Transwell chamber assay indicates that the cells invasiveness gradually decrease with the increase of celecoxib dose(50-200umol/L)(P<0.05).RT-PCR results indicate that the expression of COX-2 mRNA gradually decreases with the increase of celecoxib dose(50-200umol/L)(P<0.05).2.There is signifficant inhibitory effect of celecoxib on xenografts in nude mice, with the increase of celecoxib dose the inhibitory rates also gradually improve(respectively 32.4% and 48.6%). RT-PCR results indicate that the expression of COX-2 mRNA gradually decreases with the increase of celecoxib dose. Immunohisto- chemistry results indicate that the expression of COX-2 protein and microvessel density in tumor samples gradually decrease with the increase of celecoxib dose. There is significant difference contrast between test and control groups, as well as between two test groups(P<0.05).Conclusions:Cyclooxygenase-2 selective inhibitor Celecoxib can inhibit Human Endometrium Adenocarcinoma in vitro and in vivo, The mechanism may be associated with down-regulation of COX-2 expression and decrease of microvessel density in tumor tissue.