A Human Fab-Based Immunoconjugate Specific for the LMP1 Extracellular Domain Inhibits Nasopharyngeal Carcinoma Growth In Vitro and In Vivo

Abstract

Nasopharyngeal carcinoma (NPC) is a major cause of cancer-related death in Southeast Asia and China. Metastasis and relapse are the primary cause of morbidity and mortality in NPC. Recent evidence suggests that the Epstein-Barr virus latent membrane protein 1 (LMP1) is exclusively expressed in most NPC and is a potential target for biotherapy. In this study, we successfully prepared a novel human antibody Fab (HLEAFab) against LMP1 extracellular domain, which was subsequently conjugated with mitomycin C (MMC), thus forming an immunoconjugate (HLEAFab-MMC). The effects of HLEAFab-MMC on proliferation and apoptosis in NPC cell lines HNE2/LMP1 and the inhibition rate of growth of NPC xenografts in nude mice were examined. The inhibition rate of HNE2/LMP1 cell proliferation was the highest for HLEAFab-MMC (76%) compared with MMC (31%) and HLEAFab (22%) at a concentration of 200 nmol/L and showed dosedependent fashion. The apoptosis rate of HNE2/LMP1 cell lines was 13.88% in HLEAFab-MMC group, 3.04% in MMC group, 2.78% in HLEAFab group, and 2.10% in negative control group at the same concentration, respectively. In vivo, the inhibition rate of growth of NPC xenografts in nude mice was 55.1% in HLEAFab-MMC group, 26.5% in MMC group, and 5.64% in HLEAFab group. In summary, our findings show that HLEAFab-MMC is a unique immunoconjugate with the potential as a novel therapeutic agent in the treatment of LMP1-expressing NPC. Mol Cancer Ther; 11(3); 594-603. Ó2011 AACR.

Epstein-Barr Virus-Specific Humoral Immune Responses in Health and Disease

“…This apparent void in the anti-EBV humoral immune repertoire may open options for de novo immunisation with peptides derived from these extracellular domains, in order to fill this immunological gap and to create therapeutic antibody responses that potentially can eliminate EBV-driven tumours expressing LMP1 and LMP2. Experiments in animal models and selection of human phage-derived antibodies are in progress and hold promise to achieve such a goal (Middeldorp 2001;Delbende et al 2009;Paramita et al 2011;Chen et al 2012). …”

LMP1 promotes nasal NK/T-cell lymphoma cell function by eIF4E via NF-κB pathway

“…Studies of LMP1 in nasopharyngeal carcinoma indicated that LMP1 can enhance nasopharyngeal carcinoma cell migration and invasion. Moreover, the human Fab-based immune-conjugate specific for the LMP1 extracellular domain can inhibit nasopharyngeal carcinoma growth both in vitro and in vivo (14,15). These finding suggest that LMP1 may play an important role in the progression of ENKTL.…”

Blockage of LMP1-modulated store-operated Ca2+ entry reduces metastatic potential in nasopharyngeal carcinoma cell

“…Human nasopharyngeal carcinoma (NPC) cell lines CNE1 (well-differentiated) and HNE2 (poorly-differentiated) stably expressing EBV-encoded LMP1 were provided by Xiangya Central Experiment Laboratory (Changsha, China), which were established by the introduction of full-length LMP1 cDNA into LMP1-negative CNE1 and HNE2 wild cells, respectively [15][16][17][18][19][20][21]. The LMP1 expression was confirmed by western blotting (anti-EBV LMP1 antibody, Abcam Corp., Cambridge, UK).…”