Diallyl Disulfide Up-regulating MiR-7 To Influence Chemosensitivity Of Human Gastric Cancer SGC7901 Cell

Objective: This study on the basis of previous experiments,after treatment of gastric cancer cells with diallyl disulfide(DADS),the expression of miR-7 was up-regulated significantly,which may associated with the chemosensitivity of gastric cancer cell.To study the effect of miR-7,which up-regulated by DADS,on chemosensitivity of human gastric cancer SGC7901 cell line and its related molecular mechanism.In order to show that mi R-7 was one of the targets of DADS,which can enhance the chemosensitivity of gastric cancer.Methods: By cultivating the laboratory has constructed low virus mir-7 stable overexpression SGC7901 cell line(SGC7901/miR-7),and SGC7901,SGC7901/VCR,which were stored by our laboratory cell bank.After treated with DADS,MTT assay was used to detect the chemosensitivity of 5-Fu for each cell line.The changes of EGFR,XIAP,Caspase-3,Bcl-2,P-gp protein and mRNA expression in SGC7901,SGC7901/VCR,and SGC7901/miR-7 were detected by Western blot,immunofluorescence and qRT-PCR.The apoptosis rate of each group was detected by flow cytometry.Results: 1.The difference of each group to 5-Fu chemotherapy sensitivity.MTT assays showed that after the treatment with DADS(non cytotoxic dose 8mg/L)could enhance the sensitivity of SGC7901 and SGC7901/VCR to 5Fu(P<0.05),And mi R-7 overexpression group can also enhance the cytotoxicity of 5Fu compared with negative control group(P<0.05).2.The apoptosis rate of each group was detected by flow cytometry.The flow cytometry showed that after the treatment with DADS,the apoptosis rate of SGC7901/VCR and SGC7901 increased significantly compared with the untreated group(P<0.05).Compared with the normal SGC7901 and negative transfection group,the apoptosis rate of SGC7901/miR-7 group was increased significantly(P<0.05),while there was no significant difference between negative transfection group and normal SGC7901(P > 0.05).3.The changes of EGFR,XIAP,Caspase-3,Bcl-2,P-gp protein and mRNA expression in each groups.The cell immunofluorescence showed that EGFR,XIAP,Caspase-3,Bcl-2,P-gp in SGC7901 cells were mainly distributed in the cytoplasm.Meanwhile,cell immunofluorescence and Western blot showed that after treatment SGC7901 and SGC7901/VCR cell lines with DADS(30ug/mL),the protein of EGFR,XIAP,Bcl-2,P-gp were significantly decreased,Caspase-3 was significantly increased,compared with the untreated group(P<0.05).And compared with the negative transfection group,EGFR,XIAP,Bcl-2,P-gp protein also showed significantly decreased,Caspase-3 significantly increased in miR-7 overexpression group.The results of qRT-PCR were consistent with Western blot and cell immunofluorescence.Conclusion:1.DADS enhance the sensitivity to 5-FU and increase the apoptosis rate of SGC7901 was associated with up regulation of miR-7.2.DADS and miR-7 can upregulating the expression of Caspase-3 and down-regulating EGFR,XIAP,Bcl-2,P-gp.