The Inhibition Of Celecoxib Combined With PDTC On SGC-7901Gastric Cancer Cells

Objective To investigate the effect of inhibition and its mechanism about the selective COX-2inhibitor celecoxib,and NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) on human gastric cancer cell line SGC-7901. Then supply the experimental and theoretical basis for the treatment of gastric cancer.Methods SGC-7901cells were respectively treated in vitro with celecoxib (50,100μmol/l)and PDTC(50、100μmol/l) or combination (25/25、50/50μmol/l).The methyl thiazolyl tetrazolium (MTT) assays were used to measure the growth inhibition rate of cells. TUNEL assays were used to measure the in situ apoptosis of gastric cancer cells.RT-PCR assays the expression levels of COX-2、NF-κB、 caspase-3. Through the comparison of cell apoptosis and gene expression of SGC-7901treated by single-agent and combined treatment,Analysis the growth inhibition of the combination drugs on gastric cancer cells.Result:1. The growth inhibition of gastric cancer cells by MTT.(1)The groups of celecoxib:after treated cells by different times,the growth inhibition of celecoxib groups with100μmol/l were higher than the celecoxib groups with50μmol/l,the difference was statistically significant (P<0.05).(2)The groups of PDTC:after treated teh cells for72h, the growth inhibition of PDTC groups with100μmol/l were higher than the PDTC groups with50μmol/l,the difference was statistically significant (P<0.05).(3)The celecoxib groups compared with the combination groups:after treated the cells for72h,The growth inhibition of the celecoxib group with50μmol/l had no difference compared with the combination group(25/25μmol/l)(P>0.05). While the combination groups(50/50μmol/l) compared with the celecoxib groups(100μmol/l),the growth inhibition of the former were higher than the latter, the difference was statistically significant(P<0.05).(4)The PDTC groups compared with the combination groups:after treated teh cells for72h,the growth inhibition of the PDTC treated groups with the concentration of50μmol/l were lower than the combination groups(25/25μmol/l),the difference was statistically significant (P<0.05).While the combination groups(50/50μmol/l) compared with the PDTC groups(100μmol/l),the growth inhibition of the former were higher than the latter, the difference was statistically significant(P<0.05).(5)The combination treatment groups:after treated cells by different times, the growth inhibition of the combination groups with50/50μmol/l were higher than the combination groups with25/25μmol/l,the difference was statistically significant (P <0.05).2. The comparison of apoptotic index.After treated24hours by the groups of celecoxib (100μmol/l) with the apoptosis index (31.67±4.04%), PDTC (100μmol/1) with the apoptosis index (39.33±5.13%),or combination groups (50/50μmol/1) with the apoptosis index (58.00±7.00%), the apoptotic index of experimental group was significantly different compared with negative control which apoptosisis index is (1.03±0.21%)(P<0.05).3. The expression level of NF-κB,caspase-3and COX-2mRNA in each group. The expression level of NF-κB and caspase-3in the drug group of celecoxib(50μmol/l) had no difference compared with the negative control group,while the expression level of COX-2had decreased,the difference was statistically significant(P<0.05).The expression of NF-κB,caspase-3and COX-2treated by celecoxib(100μmol/l) or PDTC(100μmol/l) were all different with negative control group(P<0.05).The combination group (25/25μmol/l) or (50/50μmol/l) compared with the negative control,the expression level of NF-κB and COX-2had decreased,while the expression of caspase-3had increased.the difference was statistically significant(P<0.05).Conclusions1.The drug celecoxib or PDTC alone can inhibit the proliferation of gastric cancer cells,and promote the apoptosis,and had the concentration-dependent.While combined with2drugs,the effect had a more pronounced.the mechanism may associated with inhibiting the expression of NF-κB、COX-2, then promote the expression of caspase-3.2.The expression level of NF-κB and COX-2mRNA in PDTC treated group were lower than the negative control,confirmed that PDTC can inhibite the expression of COX-2,thereby inhibiting the proliferation of gastric ancer cells. While the expression level of COX-2and NF-KBmRNA in celecoxib treated group were lower than the negative control,shows that celecoxib can also effect the activity of NF-κB,thereby effecting the apoptosis of cells.3.Celccoxib and PDTC both can inhibit the proliferation of gastric cancer cells,then induce the apoptosis,and they are non-cytotoxic drugs,maybe bring new prospects for the adjuvant treatment of gastric cancer.