the EBV-encoded latent membrane proteins have been associated with activation of PI3K/Akt and extracellular signal-regulated kinase /MAPK, and LMP2A has been shown to activate the protooncogenic Wnt signalling pathway. However, there is scant literature addressing the role of GSK3b in the signalling pathways underlying the carcinogenesis of NPC. In a previous study, we demonstrated that GSK3b inactivation is associated with tumour stage of NPC through regulation of PMS2. Similarly, Morrison et al. established the significance of GSK3b inactivation in the ubiquitin-mediated degradation and stabilisation of b-catenin production and NPC progression. In this study, although we were unable to identify the specific 284661-68-3 citations phosphorylation site of EZH2, but the observed interaction of GSK3b and EZH2 in NPC cells prompted us to further investigate the regulatory effect of GSK3b on EZH2 production in vitro. For this reason, we then transfected GSK3b-CA or GSK3b-KD plasmid or used Potassium clavulanate:cellulose (1:1) lithium as a specific inhibitor to regulate GSK3b activity in cell lines. Since we observed significant change in halflife of EZH2 protein but not mRNA expression in response to GSK3b transfection, we concluded that GSK3b may exert its effect on EZH2 expression in the protein level. When GSK3b activity was enhanced by transfection with GSK3b-CA, we observed that active GSK-3b production was significantly upregulated and EZH2 production was significantly inhibited in CNE-1 and CNE-2 cells. Moreover, when GSK3b activity was inhibited upon transfection with GSK3b-KD or lithium treatment, both p-GSK3b and EZH2 were significantly upregulated in CNE-1 and CNE-2 cells. This finding suggested there may exist a balance between activated and inactivated form of GSK3b, and the mechanism still need further investigation. Although we did not exclude other pathways that may be involved in EZH2 overexpression in human NPC tissues, our finding provided the preliminary evidence that EZH2 expression is regulated by GSK3b with phosphorylation on Ser9. EZH2 belongs to the family of polycomb group proteins and plays a master regulatory role in many important cellular processes. There is increasing evidence that overexpression of the EZH2 gene occurs in a variety of hum
