Transcriptional activation of NF-κB activity by Epstein–Barr virus (EBV) LMP1 as a selective therapeutic strategy for EBV-associated diseases

Abstract

Epstein-Barr virus (EBV) has been known to be associated genes were subjected to the GCV sensitivity test. Results with many malignant tumors, including nasopharyngeal showed that cells expressing both the LMP1 and the HSVtk carcinoma (NPC). Previous studies have indicated that an genes were highly sensitive to GCV treatment. These cells EBV-encoded oncoprotein, latent membrane protein 1 were introduced into nude mice subcutaneously and (LMP1), is expressed in many NPC tissues. LMP1 has tumors became palpable within 2 weeks. GCV was then been shown to stimulate HIV LTR through the two NF-B introduced intraperitoneally to these mice and the sizes of binding sites within this promoter. In this study, we examthe tumors were measured daily. Results showed that the ined the feasibility of using this property of LMP1 as a tumors regressed in the group of mice carrying cells that therapeutic strategy for the treatment of NPC. This therapy stably expressed both the LMP1 and the HSVtk genes, but consists of the preferential killing of the LMP1-expressing not in mice carrying cells containing LMP1 or HSVtk alone. cells by gene transfer using the NF-B-mediated herpes Our data indicate that the HSVtk gene expressed from a simplex virus thymidine kinase (HSVtk)/ganciclovir (GCV) NF-B-binding motif-containing promoter that is regulated system. The 800-bp HIV-LTR, which contains two NF-B by LMP1 may be used as an in vivo gene therapy strategy binding sites, was used to drive the HSVtk gene. Stable of EBV LMP1-expressing cancers such as NPC. C33A cell clones expressing the LMP1 and the HSVtk

Electroporation-mediated and EBV LMP1-regulated gene therapy in a syngenic mouse tumor model

“…15 In this study, we improved the system by custom-designing a transcriptional cassette containing an epithelial-specific Balb/c mice were inoculated with 1x10 5 CT-26-NLMP1 or CT-26 cells to induce tumors. Mice were divided into six groups, each comprising six animals.…”

“…LMP1 activates HIV-LTR-regulated HSVtk gene expression via two copies of the NF-kB-binding motif, and tumors expressing LMP1 and HSVTK are sensitive to GCV treatment in nude mice. 15 However, HIV-LTR may not be an ideal promoter to direct the expression of therapeutic genes, as it may integrate into the genome and result in the activation of cellular genes that are initially in an inactivated state. To circumvent this problem, we replaced HIV-LTR with EBV ED-L1E, an upstream promoter of the LMP1 gene.…”

“…Plasmids p2kB-EDL1E-tk and p6kB-EDL1E-tk were generated by insertion of an B0.8 kb SmaI-BglII fragment (containing two or six copies of the NF-kB-binding motif and ED-L1E promoter) of p2kB-EDL1E-Luc and p6kB-EDL1E-Luc into ClaI-BglII-digested pHSV-106 (GibcoBRL). The pLTR-tk plasmid is described by Wu et al 15 …”

“…As shown in Fig 5, tissues injected with p6kB-EDL1E-tk displayed Bthree-fold higher TK activity than those treated with p2kB-EDL1E-tk, and Btwofold higher activity than previously examined HIVLTRtk. 15 In vivo effect of a combination of GCV and kB-mediated TK activation on LMP1-expressing tumor growth…”

“…15 The HSVtk gene in the earlier study was expressed from the HIVLTR sequence containing two copies of the NF-kB motif, and activated by NPC-derived LMP1 (NLMP1). 16 Cells expressing both NLMP1 and HSVtk genes were highly sensitive to GCV treatment, and tumors induced in nude mice regressed.…”