Role Of Tegafur Gimeracil Oteracil Potassium Combined With Celecoxib On Human Gastric Cancer Cell Lines And Its Mechanism Of Cooperative Effect In Nude Mice

ObjectiveTo investigate the anti-tumor effect and the possible mechanism ofcelecoxib(selective Cyclooxygenase-2inhibitor) combined withchemotherapy drug Tegafur Gimeracil Oteracil Potassium on subcutaneousxenograft tumor of human gastric cancer in nude mice.Methods(1) To identity whether COX-2and VEGF-C expressed in humangastric cancer SGC-7901cell with immunocytochemistry method.(2) Human gastric cancer SGC-7901cells were inoculated subcutane-ously in nude mice to establish a xenograft tumor model of gastric cancer.After the largest diameter of tumors reached about5mm,the nude mice wererandomly divided into four groups: the control group, the celecoxib group,the Tegafur Gimeracil Oteracil Potassium group, and the combination group.The drug was administerd respectively for21days. After treatment tumor tissues were collected, the weight change of the nude mice before and aftertreatment was measured, tumor volume、tumor weight were measured, andtumor inhibition rate was calculated, and the side effect of drug therapy wasassessed.Apoptosis was determined by TUNEL assay, the expression levelof PCNA、Bcl-2、Caspase-3、COX-2、VEGF-C protein were determinedby immunohistochemistry. Using Podoplanin to label lymph vessels,calculated the lymphatic vessel density.Results(1) Tumor formation rate: The largest diameter of tumors in tweenty-sixnude mice reached about5mm after eighteen days of inoculation,other fivenude mice’s didn’t. Tumor formation rate was83.9%.(2) Tumor volume、tumor weight、tumor inhibition rate: There wasn’tobvious side effect and the nude mice’s body weight were higher after thetreatment(P<0.05).After the treatment, tumor volume in four groups were asfollows: the control group(2288.67±753.87)mm3、 the celecoxibgroup(1583.75±345.25)mm3、the Tegafur Gimeracil Oteracil Potassiumgroup(1142.42±229.17)mm3、the combination group（485.00±255.25）mm3.Compared with the control group, tumor volume in the treatmentgroups was smaller(P<0.05).Tumor volume of the combination group wassmaller than the celecoxib group and the Tegafur Gimeracil OteracilPotassium group(P<0.05).The tumor volume inhibition rate of the celecoxibgroup、the Tegafur Gimeracil Oteracil Potassium group、the combination group were30.8%,50.1%,78.8%, respectively.After the treatment, tumorweight in different groups were as follows: the control group（2.14±0.79）g、the celecoxib group（1.44±0.50）g、the Tegafur Gimeracil OteracilPotassium group（1.11±0.34）g、the combination group（0.44±0.27）g.Compared with the control group, tumor weight in the treatment groups waslighter(P<0.05).Tumor weight of the combination group was lighter than thecelecoxib group and the Tegafur Gimeracil Oteracil Potassiumgroup(P<0.05). The tumor weight inhibition rate of the celecoxib group、theTegafur Gimeracil Oteracil Potassium group、the combination group were32.71%,48.13%,79.44%, respectively.(3) Apoptosis rate: The apoptosis rate of the control group、 thecelecoxib group、the Tegafur Gimeracil Oteracil Potassium group、thecombination group were as follows：11.19%±1.73%、30.98%±2.00%、39.16%±2.74%、58.93%±3.70%.The treatment groups’ apoptosis rate washigher than the control group’s obviously(P<0.01)，the combination group’swas higher than the celecoxib group and the Tegafur Gimeracil OteracilPotassium group(P<0.01).(4) Protein expression: COX-2and VEGF-C expressed in humangastric cancer SGC-7091cell before treatment.The expression of PCNA、Bcl-2in the treatment groups were lower than the control group(P<0.01),andthe combination group was lower than single drug group(P<0.05). Theexpression of Caspase-3in treatment groups were higher than the control group(P<0.05),and the combination group was higher than single druggroup(P<0.01). The expression of COX-2、VEGF-C in the celecoxib groupand the combination group were lower than the control group(P<0.05),butthere was no significant difference between the Tegafur Gimeracil OteracilPotassium group and the control group(P>0.05). and there was no significantdifference between the combination group and the celecoxib group(P>0.05).The lymphatic vessel density of the control group、the celecoxib group、theTegafur Gimeracil Oteracil Potassium group、the combination group were asfollows：（8.60±1.52）/HF、（4.60±1.14）/HF、（8.00±1.58）/HF、（3.80±1.30）/HF. The lymphatic vessel density of the celecoxib group and thecombination group were lower than the control group and the TegafurGimeracil Oteracil Potassium group (P<0.05), but there was no significantdifference between the Tegafur Gimeracil Oteracil Potassium group and thecontrol group(P>0.05). And there was no significant difference between thecombination group and the celecoxib group(P>0.05).Conclusion(1) COX-2and VEGF-C expressed in human gastric cancer SGC-7091cell.(2) Celecoxib、Tegafur Gimeracil Oteracil Potassium both showedobvious anti-tumor effect when administrated alone on subcutaneousxenograft tumor model of human gastric cancer in nude mice. The possiblemechanism was that celecoxib reduced the expression of COX-2、VEGF-C 、Bcl-2protein,up-regulatedtheexpressionofCaspase-3protein,asaresultdecreased lymphatic vessel density, inhibited proliferation and promotedapoptosis of the tumor cell.(3) The antitumor effect of the combination group was better than theTegafur Gimeracil Oteracil Potassium group and acted synergistically in thecombination group. The possible mechanism was that celecoxib reduced theexpression of COX-2、VEGF-C、Bcl-2protein, up-regulated the expressionof Caspase-3protein, decreased lymphatic vessel density.When combinedwith Tegafur Gimeracil Oteracil Potassium,the anti-tumor effect ofinhibiting proliferation and promoting apoptosis of the tumor cell andinhibiting lymphangiogenesis was amplificated and enhanced obviously, soas to realize the inhibitory effect on growth and metastasis of gastric cancer.This research provided a new theoretical basis for celecoxib using for gastriccancer’s comprehensive treatment in clinical.