Induction of Epstein-Barr virus lytic replication by recombinant adenoviruses expressing the zebra gene with EBV specific promoters

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 lyric 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 lyric 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.