Cytolytic virus activation therapy and treatment monitoring for Epstein-Barr virus associated nasopharyngeal carcinoma in a mouse tumor model

Zlata Novalić, Sandra A. W. M. Verkuijlen, Mariska Verlaan, Jos L.H. Eersels, Inge de Greeuw, Carla F.M. Molthoff, Jaap M. Middeldorp*, Astrid E. Greijer

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Undifferentiated nasopharyngeal carcinoma (NPC) is 100% associated with Epstein-Barr virus (EBV). Expression of viral proteins in the tumor cells is highly restricted. EBV reactivation by CytoLytic Virus Activation (CLVA) therapy triggers de novo expression of early viral kinases (PK and TK) and uses antiviral treatment to kill activated cells. The mechanism of tumor elimination by CLVA was analyzed in NPC mouse model using C666.1 cells. Valproic acid (VPA) was combined with gemcitabine (GCb) to stimulate EBV reactivation, followed by antiviral treatment with ganciclovir (GCV). A single cycle of CLVA treatment resulted in specific tumor cell killing as indicated by reduced tumor volume, loss of EBV-positive cells in situ, and paralleled by decreased EBV DNA levels in circulation, which was more pronounced than treatment with GCb alone. In vivo reactivation was confirmed by presence of lytic gene transcripts and proteins in tumors 6 days after GCb/VPA treatment. Virus reactivation was visualized by [124I]-FIAU accumulation in tumors using PET-scan. This studied showed that CLVA therapy is a potent EBV-specific targeting approach for killing tumor cells. The [124I]-FIAU appears valuable as PET tracer for studies on CLVA drug dosage and kinetics in vivo, and may find clinical application in treatment monitoring.

Original languageEnglish
Pages (from-to)2207-2216
Number of pages10
JournalJournal of Medical Virology
Volume89
Issue number12
DOIs
Publication statusPublished - 1 Dec 2017

Cite this

Novalić, Z., Verkuijlen, S. A. W. M., Verlaan, M., Eersels, J. L. H., de Greeuw, I., Molthoff, C. F. M., ... Greijer, A. E. (2017). Cytolytic virus activation therapy and treatment monitoring for Epstein-Barr virus associated nasopharyngeal carcinoma in a mouse tumor model. Journal of Medical Virology, 89(12), 2207-2216. https://doi.org/10.1002/jmv.24870