Anti-EBV Latent Membrane Protein 1 monoclonal antibody, clone ES3,ES4,ES5,ES6

Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) activation of NF-kappa B is pivotal for EBV-infected B lymphocyte survival. Herein, we found that LMP1 markedly rescued the suppressed the proliferation of several nasopharyngeal carcinoma (NPC) cell lines caused by a Toll-like receptor 3 (TLR3) ligand poly (I:C). We profiled the expression alterations of TLR3 and LMP1 within these NPC cell lines in response to poly (I:C) treatment, and found a high correlation between them ws found, suggesting potential involvement of TLR3 in LMP1 signaling. Then, cells deficient in TLR3 were used to assess its role in poly (I:C)-induced inhibition of cell proliferation and LMP1-mediated NF-kappa B activation. NF-kappa B p65 activation and the consequent pro-inflammatory responses were unresponsive to poly (I:C) stimulation after TLR3 knockdown (KD), and NOS2 and MMP9 were substantially suppressed in CNE1-745, but nearly normal in LMP1-overexpressed CNE1-LM P1-745 cells. This suggests an alternative pathway that LMP1 may depend on, in terms of NOS2 and MMP9 regulation, whereas an unusual TLR3-dependent expression of c-Myc was identified. Consistently, poly (I:C)-induced retarded growth was reversed by TLR3 silencing, which was especially enhanced in LMP1-overexpressed cells. TLR3 is essential for poly (I:C)-incited NPC cell death, and occupies a critical role in LMP1-mediated NF-KB activation. Our findings provide new insight into the mechanism underlying LMP1-involved EBV-associated pathogenesis of refractory NPC, thereby potentially improving treatment outcome.

Nasopharyngeal carcinoma (NPC) is an aggressive head and neck cancer characterized by Epstein-Barr virus (EBV) infection and dense lymphocyte infiltration. The scarcity of NPC genomic data hinders the understanding of NPC biology, disease progression and rational therapy design. Here we performed whole-exome sequencing (WES) on 111 micro-dissected EBV-positive NPCs, with 15 cases subjected to further whole-genome sequencing (WGS), to determine its mutational landscape. We identified enrichment for genomic aberrations of multiple negative regulators of the NF-kappa B pathway, including CYLD, TRAF3, NFKBIA and NLRC5, in a total of 41% of cases. Functional analysis confirmed inactivating CYLD mutations as drivers for NPC cell growth. The EBV oncoprotein latent membrane protein 1 (LMP1) functions to constitutively activate NF-kappa B signalling, and we observed mutual exclusivity among tumours with somatic NF-kappa B pathway aberrations and LMP1-overexpression, suggesting that NF-kB activation is selected for by both somatic and viral events during NPC pathogenesis.