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ISSN 1672-9145 Acta Biochim Biophys Sin 2005, 37(4): 215–220 CN 31-1940/Q

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Induction of Epstein-Barr Virus Lytic Replication by Recombinant Adenoviruses Expressing the Zebra Gene with EBV Specific Promoters

Lu CHEN, Juan YIN, Yi CHEN, and Jiang ZHONG*

Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China

Abstract The latent Epstein-Barr virus (EBV) is found in the cells of many tumors. For example, EBV is detectable in almost all cases, and in almost all tumor cells, of non-keratinizing nasopharyngeal carcinoma. Activating the latent virus, which will result in its lytic replication and the death of tumor cells, is a potential approach for the treatment of EBV-associated cancers. In this study, three recombinant adenoviruses were constructed to express the Zebra gene, an EBV gene responsible for switching from the latent state to lytic replication. EBV-specific promoters were used in order to limit Zebra expression in EBV-positive cells, and reduce the potential side effects. The EBV promoters used were Cp, Zp and a dual promoter combining both promoters, CpZp. The Zebra protein was detected in HEK293 cells as well as the EBV-positive D98-HR1 cells infected with recombinant viruses. An EBV lytic replication early antigen, EA-D, was also detected in infected D98-HR1, implying the initiation of lytic replication. In the cell viability assay, Zebra-expressing adenoviruses had little effect on EBV-negative HeLa cells, while significantly reducing the cell viability and proliferation of D98-HR1 cells. The results indicate that EBV virus promoters can be used in adenovirus vectors to express the Zebra gene and induce EBV lytic replication in D98-HR1 cells.

Key words Epstein-Barr virus; recombinant adenovirus; lytic replication; cancer

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Received: December 22, 2004 Accepted: February 18, 2005

This work was supported by a grant from the “Shuguang” Program of the Shanghai Municipal Education Foundation

*Corresponding author: Tel, 86-21-55664332; Fax, 86-21-65650149; E-mail, [email protected]