The Molecular Mechanism Of Celecoxib Regulating Apoptosis In Gastric Cancer Cells Via PI3K/Akt Pathway

Objective:To investigate the mechanism of celecoxib regulates apoptosis in human gastric cancer cell line SGC-7901 via PI3K/Akt signaling pathway.Methods:The effect of celecoxib on the growth of human gastric cancer cell line SGC-7901 were studied by MTT assay. Acridine orange staining was used to abserve the morphological changes of cell. Transmission electron microscopy(TEM) was used to abserve the structure changes of cell. Apoptosis was assessed by terminal deoxynucleotidyl transferse-mediated dUTP nick and labeling(TUNEL). The apoptotic rate was observed by flow cytometry(FCM). Real time quantitative RT-PCR and western blot were used to analyse the changes of caspase-8,caspase-9,Akt mRNA and protein levels in SGC-7901 cell after treatmented with celecoxib.Results:The proliferation of SGC-7901 cells were deareased in celecoxib-treated group, This changes were in a time-and dose-dependent manner. Apoptotic bodies were observed by acridine orange staining. A lot of apoptotic tumer cells were measured by TUNEL. Typical apoptotic changes such as nuclear membrane shrinkage,chromatin condensation,chromatin marginalized and apoptotic bodies were observed by TEM. Interestingly, intense autophagic vacuolization and autophagosome was detected in distinct cytoplasmic areas of the affected cell. The SGC-7901 cell treated with celecoxib for 72h, FCM showed the apoptotic rate increased from 2.24% to 35.67%. The expression of Akt mRNA have no significant changes, p-Akt protein was decreased in treated cells. This changes were in a time-and dose-dependent manner(P<0.05). The expression of caspase-8 mRNA was increased sharply in SGC-7901 cell treated with celecoxib. This changes were in a time-and dose-dependent manner(P<0.05). The expression of caspase-9 mRNA was increased in SGC-7901 cell treated with celecoxib,but the changes of caspase-9 mRNA treated with 125μmol/L celecoxib 24 hours compared with control group have no difference. There is difference between the expression of caspase-9 mRNA treated with 125μmol/L celecoxib 48 hours and 72 hours compared with control group(P<0.05). The changes of caspase-9 mRNA treated with 75μmol/L celecoxib 72 hours compared with control group have no difference. There is difference between the expression of caspase-9 mRNA treated with 100μmol/L and 125μmol/L celecoxib 72 hours compared with control group(P<0.05). This changes were in a time-and dose-dependent manner. The expression of procaspase-8,procaspase-9 protein were decreased sharply in SGC-7901 cell treated with celecoxib. This changes were in a time-and dose-dependent manner(P<0.05).Conclusions:1. The anti-cancer effect of celecoxib on gastric cancer cell line SGC-7901 might be partly medicate by apoptosis and autophagic cell death via PI3K/Akt signaling pathway. 2. The proliferation of SGC-7901 cells was dearease in celecoxib-treated group.3. The molecular mechanism of celecoxib regulates apoptosis are death-receptor pathway and mitochondtrial pathway.