The Influence Of SiRNA Targeting LMP1 Gene On Expression Of AP-1 And Its Related Factors

Epstein-Barr(EBV) is an important DNA tumor virus,which has close relationship with many kinds of human lymphocytic system malignant tumor,for example,Burkitt's lymphoma,transplant B lymphocytoma,Hodgkin's disease,and T lymphocytoma;It also takes an important part in the development of epithelial tumour.The relationship with nasopharyngeal carcinoma(NPC) has been confirmed.Latent membrane protein(LMP1), an admitted EBV tumorigenesis protein,one of the protein encoded by EBV latent gene BNLF1 located in BamH I Nhet,was able to transform cell lines and alter the phenotype of cells due to its oncogenic potential.LMP1 could transform rodent animal fibroblast in vitro and could mediate cell proliferation,inhibit cell apoptosis and cell differentiation.LMP1 is relevant with NPC poor diffferention and promotes tumor invasion and metastasis.It has been showen that EBV genome could be found in all EBV positive carcinoma tissues but couldn't be found in EBV negative carcinoma tissues, which suggests EBV might be the perfect target and we could selectively kill EBV positive carcinoma cells by some way.Objective To investigate the influence of LMP1 silence on AP-1 signal transduction pathway and its downstream factors involved with cell transformation, proliferation and apoptosis.Methods The chemically synthetic siRNA targeting LMP1 was transfected into EBV positive gastric carcinoma epithelial cell line by lipofectamine 2000 at 50nM final concentration.The protein expression of c-Jun,JunB and CDK4 was tested by Western blotting.The mRNA of c-Jun,Survivin,CDK4 and MMP9 were tested by RT-PCR.The expression of Survivin were tested by immunohistochemmistry.Results Compared with the cell control,CDK4 mRNA was upregulated (P＜0.05),c-Jun mRNA and Survivin mRNA were downregulated siRNA 24h,48h,72h, 96h and 120h post-transfection(P＜0.05).The level of c-Jun and Survivin mRNA was much lower siRNA 24h and 48h post-transfection respectively.MMP9 mRNA was also downregulated during the first 3 days(P＜0.05),degraded obviously siRNA 48h post-transfection(P＜0.05).CDK4 protein expression was also upregulatede at each time,c-Jun and JunB protein expression was downregnlated siRNA 24h,48h,72h and 96h post-transfection,compared with cell control.Immunohistochemmistry results showed that the Survivin expression was down 24h,48h and 72h post-transfection (P＜0.05).Conclusion The specific silence of LMP1 could influence AP-1 signal transduction pathway and its related factors,then inhibit cell proliferation and promote cell apoptosis.