1.Epstein-Barr virus encoded latent membrane protein 1 induces TRAF1 expression to promote anti-apoptosis activity via NF-kappaB signaling pathway in nasopharyngeal carcinoma.
Chengxing WANG ; Midan AI ; Wei REN ; Hui XIAO ; Xiaoyan LI ; Faqing TANG ; Huanhua GU ; Wei YI ; Xinxian WENG ; Xiyun DENG ; Ya CAO
Chinese Medical Journal 2003;116(7):1022-1028
OBJECTIVESTo identify whether Epstein-Barr virus (EBV) encoded latent membrane protein 1 (LMP1) can induce tumor necrosis factor receptor-associated factor 1 (TRAF1) expression and promote its anti-apoptosis activity via the NF-kappaB signaling pathway, and assess that LMP1 suppresses apoptosis in nasopharyngeal carcinoma (NPC).
METHODSA stable transfected cell line HNE2-LMP1 was established by introducing LMP1 cDNA into HNE2 cells. Transactivation of TRAF1 was determined by luciferase reporter assay, while expression of TRAF1 mRNA was detected by RT-PCR and expression of TRAF1 protein and caspase 3 by Western blot analysis. Apoptosis activity was observed through fluorescence staining.
RESULTSLMP1 induced TRAF1 expression in NPC cells and caused a decrease in apoptosis. This induction could be blocked by antisense LMP1. Moreover, LMP1-mediated induction of a TRAF1 promoter-driven reporter gene was significantly impaired when the kappaB site kappaB1 or kappaB5 was disrupted, whereas mutation of kappaB3 had only a minor effect on LMP1 dependent up-regulation of the reporter gene.
CONCLUSIONLMP1 induces TRAF1 expression and promotes its anti-apoptosis activity via the NF-kappaB signaling pathway, which may be one of the mechanisms that LMP1 uses to suppress apoptosis in NPC cells.
Apoptosis ; physiology ; Humans ; NF-kappa B ; physiology ; Nasopharyngeal Neoplasms ; physiopathology ; Protein Biosynthesis ; Signal Transduction ; physiology ; TNF Receptor-Associated Factor 1 ; Tumor Cells, Cultured ; Viral Matrix Proteins ; physiology
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