Upregulation of interleukin-1 by Epstein-Barr virus latent membrane protein 1 and its possible role in nasopharyngeal carcinoma cell growth.

Abstract

Nasopharyngeal carcinoma (NPC) is associated with Epstein-Barr virus (EBV) infection. We previously found that interleukin (IL)-1alpha and IL-1beta significantly increased in NPC tissues. This study investigated what EBV-encoded proteins were involved in such IL-1 production. IL-1alpha and IL-1beta messenger ribonucleic acids (mRNAs) were detected in the EBV latent membrane protein 1 (LMP1) transfectant (LMP135) only by reverse transcriptase-polymerase chain reaction (RT-PCR). LMP1-mediated IL-1alpha and IL-1beta production could be enhanced by tumor necrosis factor alpha (TNF-alpha), determined by enzyme-linked immunosorbent assay (ELISA). Moreover, IL-1alpha and IL-1beta mRNAs and proteins were increased in a dose-dependent manner in epithelial cells transiently transfected by an LMP1 plasmid. Besides, immortalized human epidermal keratinocyte (RHEK-1) epithelial cells could be enhanced to proliferate by IL-1alpha and IL-1beta determined by water-soluble tetrazolium salt (WST-1) assay. EBV LMP1 is capable of upregulating IL-1alpha and IL-1beta secretions from epithelial cells and positively modulated by TNF-alpha. This may consequently contribute to tumor growth in patients with NPC.