SiRNA Interfere With The Expression Of Snail In Human Gastric Cell Line BGC-823 And The Effect On The Cell Invasion Ability By Regulating The Expression Of The Snail Gene

Objective To investigate the expression of Snail and E-cadherin protein in hunman poorly differentiated gastric adenocarcinoma BGC-823 and differentiated gastric adenocarcinoma SGC-7901; To investigate the effect on the expression of Snail and E-cadherin mRNA and protein of BGC-823 via the Snail-siRNA interference; To investigate the effect on the invasion ability of BGC-823 by regulating the expression of the Snail gene. Methods Part 1: The expreesion of Snail and E-cadherin protein was detected by using immunocytochemistry(ICC) S-P method in poorly differentiated gastric adenocarcinoma BGC-823 and differentiated gastric adenocarcinoma SGC-7901;siRNA targeting against Snail(siRNA₁,siRNA₂,siRNA₃),negative sequence siRNA and fluorescence-negative siRNA were chemical synthesized and transfected into BGC-823 cells with lipofectamine TM2000. The transfection efficiency was detected by the fluorescence microscope and flow cytometry (FCM);The expression of Snail mRNA and E-cadherin mRNA was detected by using RT-PCR;The expression of Snail protein and E-cadherin protein was detected by using Western Blot.Part 2: To regulate the expression of Snail protein,we treated BGC-823 cells with TGF-β₁ or Snail-siRNA interference. The changes of invasion ability of BGC-823 were detected by transwell cell culture chambers. Result Part 1: There were different levels of expression rate of Snail and E-cadherin in BGC-823 and SGC-7901 cells.The positive rate of Snail in BGC-823 cells was higher than that in SGC-7901 cells(P<0.05). The positive rate of E-cadherin in BGC-823 cells was lower than that in SGC-7901 cells(P<0.05) ; The transient transfection efficiency of siRNA was close to 100%;RT-PCR:The expression of Snail mRNA was lower in Snail-siRNA group(siRNA₁group,siRNA₂group,siRNA₃group) than that in blank group(P<0.05); There was no significantly different expression of Snail mRNA among the three Snail-siRNA group(P>0.05); There was no significantly different expression of Snail mRNA among the negative sequence group, the liposome group, the blank group. There was no significantly different expression of Snail mRNA between the negative sequence group and the blank group(P>0.05); There were no significantly different expression of Snail mRNA between the liposome group and the blank group(P>0.05);The expression of E-cadherin mRNA was higher in Snail-siRNA group (siRNA₁group,siRNA₂group,siRNA₃group)than that in blank group(P<0.05); There was no significantly different expression of E-cadherin mRNA among the three Snail-siRNA group(P>0.05); There was no significantly different expression of E-cadherin mRNA among the negative sequence group, the liposome group, the blank group; There was no significantly different expression of E-cadherin mRNA between the negative sequence group and the blank group(P>0.05); There was no significantly different expression of E-cadherin mRNA between the liposome group and the blank group(P>0.05).Western Blot:The expression of Snail protein was lower in siRNA₁ group than that in blank group(P<0.05);There was no significantly different expression of Snail protein between the negative sequence group and the blank group(P>0.05);The expression of E-cadherin protein was higher in siRNA 1group than that in blank group(P<0.05); There was no significantly different expression of E-cadherin protein between the negative sequence group and the blank group(P>0.05). Part 2:ICC: The expression of Snail protein was higher in TGF-β1 group than that in blank group(P<0.05); The expression of Snail protein was lower in siRNA₁ group than that in blank group(P<0.05).Transwell:The invasion ability was higher in TGF-β₁ group than that in blank group(P<0.05); The invasion ability was lower in siRNA₁ group than that in blank group(P<0.05). Conclusions(:1)BGC-823 and SGC-7901 cells had different degrees of expression of Snail and E-cadherin protein . (2) The expression of Snail gene can be effectively silenced by Snail-siRNA in gastric cancer cells BGC-823. (3) TGF-β₁ can enhance the expression of Snail protein and enhanced cell invasion ability in BGC-823 cells. (4) Snail-siRNA interference can reduce the invasive ability of the BGC-823 cells. (5) The high level of the expression of the Snail gene may be an important molecular marker of the invasion and metastasis of gastric cancer.