Epstein-Barr virus encoded latent membrane protein 1 induces TRAF1 expression to promote anti-apoptosis activity via NF-κB signaling pathway in nasopharyngeal carcinoma

摘要

Objectives To 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-κB signaling pathway, and assess that LMP1 suppresses apoptosis in nasopharyngeal carcinoma (NPC). Methods A 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. Results LMP1 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 κB site κB1 or κB5 was disrupted, whereas mutation of κB3 had only a minor effect on LMP1 dependent up-regulation of the reporter gene. Conclusion LMP1 induces TRAF1 expression and promotes its anti-apoptosis activity via the NF-κB signaling pathway, which may be one of the mechanisms that LMP1 uses to suppress apoptosis in NPC cells.