The Regulation Of COX-2 And Its Inhibitor On Apoptosis Effect In Human Cervical Carcinoma Cells

Cervical carcinoma is one of the most common tumor of women.Every year,there are 471 thousand new cases in the world,and about 200 thousand women died in the disease. The research of prevention and cure are always attached importance to by people.Now,the aim of anti-tumor therapy is the general therapy including surgical,radiation therapy,chemotherapy and biological therapy. So exploring an efficient anti-tumor medicine has become a hotspot in the areas of tumor prevention and trerapy in recent years.Recent epidemiological studies indicate that regular intake of aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce the risk of gastrointestinal tract carcinomas such as colorectal carcinoma, esophageal carcinoma, etc.A number of studies have strongly implicated that NSAIDs play a role for inhibition of COX-2 in tumor prevention. It's well known that cyclooxygenase is expressed in mammalian cells in two distinct isoforms : COX-1 and COX-2. Cox-1 gene is a constitutively expressded one that related to housekeeping function in most tissue and it mediates the synthesis of PGs required for normal physiological function. Cyclooxygenase-2 gene is regarded as a rapidly response gene and its expression can be elevated induced by inflammation,ulcer ,various tumor and many regulatory factors. It also plays a role in some pathological process such asinflammation,carcinogenesis and etc.Overwhelming evidence suggests that COX-2 play important roles in inhibition of tumor apoptosis. However, the underlying mechanisms remain unknown. Elucidating the effects of COX-2 in inhibition of cervical cancer apoptosis will further our understanding of the functions of COX-2 and provide the premise to develop novel methods to combat cervical cancer by using selective COX-2 inhibitor.AIM: To detect the expression of COX-2 in the level of tissue and cells of cervical carcinoma,and to study the effects of celecoxib on apoptosis in human cervical carcinoma cells and its possible mechanisms.METHODS: Our research work was divided into three parts. The first, detect the protein and mRNAs expression of COX-2 by immunohistochemistry and in situ hybridization.The second, The amount of apoptotic cells was measured by flow cytometry. The expressions of COX-2 and caspase-3 were detected by fluorescent immunohistochemistry , and the expressions of Bcl-2 and Bax-mRNA by RT-PCR.The last,inhibition of proliferation was measured by MTT assay. Implanted tumors were observed in nude mice administered celecoxib.The data was analyzed with SPSS 11.0 statistical software.RESULTS: Our results were spread out below:1. The overall positive expression rate of COX-2 in cervical cancer was 75.9%,higher than that in CIN,chronic cervitis and normal cervix (P<0.05).2. The intensity of expression of COX-2 in cervical cancer was not related to tumor stage and histologic type(P>0.05),and the expression of COX-2 was associated with tumor differentiation and lymph node involvement and mymometrial invasion(P<0.05).3. The overall positive expression of COX-2 protein and mRNA was observed in HeLa cells and SiHa cells,the intensity of expression of COX-2 was no significant difference.4. Apoptosis rate were 3.6%(control group), 21.8%( carbo group), 40.11%( celecoxib group),47.83%( celecoxib and carbo group), respectively. There was statistically significant difference(P<0.001).5. FACS analysis of cell cycle exhibited that the percentage of HeLa cells in G₀/G₁ phase was increased by celecoxib(from 59.1 % to 73.9 %),while in G₂/M and S phase was decreased.6. Celecoxib could induce an enhancement of the expression of Cleaved caspase-3 and decrease the expression of COX-2 in HeLa cells.7. Celecoxib could induce apoptosis in cervical cancer cell. It was found characteristic signs of apoptosis by using electromicroscopy.8. After exposuring to celecoxib, the expression of apoptosis-related Bcl-2, Bax genes did not changed by RT-PCR (P>0.05).9. Celecoxib could remarkably inhibit the growth of cervical cancer cell lines,the inhibiting effect of celecoxib was dose-dependent and time-dependent,and there was no statistically significant difference on two cell lines(P>0.05).10. In tumor implantation studies, implanted tumor in nude mice orally administrated celecoxib had a lower growth rate compared to that of vehicle control(P<0.001).CONCLUSION:1. The expressions of COX-2 can be detected in cervical tumor tissues and it is related to onset and progression and prognosis of the disease.2. The overall positive expression of COX-2 protein and mRNA was observed in HeLa cells and SiHa cells,the intensity of expression of COX-2 was no...