Effective suicide gene therapy in vivo by EBV-based plasmid vector coupled with polyamidoamine dendrimer

Abstract

This study demonstrates in vivo effectiveness of a nonviral vector system, Epstein-Barr virus (EBV)-based plasmid vector coupled with polyamidoamine (PAMAM) dendrimer (EBV/polyplex), in suicide gene therapy of cancer. The EBVbased vector is a plasmid vector containing EBV nuclear antigen 1 (EBNA1) gene and oriP from EBV genome. HSV-1 tk gene was transferred into Ewing's sarcoma cell lines, A4573 and KP-EWS-YI, by using an EBV-based plasmid vector, pSES.Tk, or a conventional plasmid vector, pS.Tk. Cells transfected with pSES.Tk/dendrimer showed approximately 100 times lower ID 50 to ganciclovir (GCV) compared

Targeted killing of carcinoembryonic antigen (CEA)-producing cholangiocarcinoma cells by polyamidoamine dendrimer-mediated transfer of an Epstein-Barr virus (EBV)-based plasmid vector carrying the CEA promoter

“…These observations with pSES.Tk and pS.Tk are consistent with our previous results using HCC and Ewing's sarcoma cell lines. 31,32 The pT.Tk/PAAD did not significantly affect the susceptibility of either cell line to GCV; the susceptibility curves were similar to those of mock-transfected cells (Fig 8, c and e). This observation is compatible with the results for pT.␤ (Fig 6d).…”

“…To transfer the suicide gene into EBNA1-negative cancer cells, we used an EBV-vector carrying both oriP and EBNA1 and succeeded in effectively killing the cancer cells both in vitro 31 and in vivo. 32 In previous studies, we employed a ubiquitous promoter and did not aim at targeting tumor cells. Therefore, the present study is the first in which an EBV-negative tumor was targeted by an EBV-based plasmid vector equipped with a tumor-specific promoter.…”

“…Recently, we have reported that use of the EBV-based plasmid vector combined with polyamidoamine dendrimer (PAAD) (EBV/polyplex) resulted in a markedly high expression in human HCC and Ewing's sarcoma cell lines, suggesting the potential usefulness of the EBV/polyplex system for gene therapy. 31,32 However, no study has been reported in which a tumor-specific promoter was employed in the EBVbased plasmid vector to target tumor cells. In this study, we combined the multimerized CEA promoter with the EBV/polyplex system to establish an efficient nonviral strategy to target CEA-producing cancers.…”

“…23,31,32 Cell type-specific expression of the ␤-gal gene Because pSES.␤ has a strong universal promoter (SR␣), ␤-gal was strongly expressed in both CEA-positive and -negative cell lines transfected with pSES.␤. To target CEA-producing cells, we constructed three EBV-based plasmids, pTES.␤, pSET.␤, and pTET.␤, that contain the CEA promoter upstream of the EBNA1 gene, ␤-gal gene, or both (Fig 2).…”

Highly efficient gene transfer into murine liver achieved by intravenous administration of naked Epstein–Barr virus (EBV)-based plasmid vectors

“…We have applied the EBV-plasmids to various preclinical studies of gene therapy, including those for hereditary, 21 chronic, 22,23 as well as malignant diseases. [24][25][26][27] In some of these studies, the EBV-based plasmid vectors were combined with cationic liposomes, 25,28 cationic polymers, 23,[25][26][27]29 electroporation 21 or gene gun, 30 while in the other studies, naked EBV-based plasmid was injected into the cardiac muscle. 22,29 In the present study, we transferred the naked EBV-based plasmid vectors to the liver through the intravascular route.…”