Effect of Epstein-Barr virus-encoded latent membrane protein 1 on β-catenin transcriptional activity and expression in nasopharyngeal carcinoma

Abstract

To investigate the contribution of latent membrane protein (LMP)1 to nasopharyngeal carcinogenesis via Wnt/β-catenin signal pathway. The recombinant plasmid pHA2-LMP1 was constructed; immunofluorescence staining, Dual-Luciferase Reporter Assay, Western blot and immunohistochemistry staining were used to study the effect of LMP1 on the transcriptional activity and expression of β-catenin. (1) Abnormal expression of β-catenin was obtained in 38 cases (50.7%, 38/75), LMP1 expression was obtained in 38 cases (50.7%, 38/75). There was significantly positive correlation between LMP1 expression and abnormal expression of β-catenin in nasopharyngeal carcinoma tissue (P = 0.008). (2) The expression of β-catenin in nuclei of NPC cell line CNE1 and CNE2 transfected with pHA2-LMP1 plasmid dramatically increased, and the expression was remarkable in poorly-differentiated NPC cell line CNE2 than that of well-differentiated CNE1 cells. (3) LMP1 expression dramatically increased the transcriptional activity of β-catenin in CNE1 and CNE2 cells transfected with pHA2-LMP1 and was in a time-dependent. The transcriptional activity of β-catenin was higher in poorly-defferentiated cell line CNE2 than that of well-differentiated NPC cell line CNE1. (4) LMP1 expression did not affect the total protein expression level of β-catenin in both CNE1 and CNE2 cell lines. EB virus-encoded LMP1 may be involved in the pathogenesis of NPC via β-catenin signal pathway.