Fluorescent Tagged Vaccinia Virus Genome Allows Rapid and Efficient Measurement of Oncolytic Potential and Discovery of Oncolytic Modulators.

Franck Gallardo,Kerstin Bystricky,Stéphane Bertagnoli,Charlotte Quentin-Froignant,Renée Brandely,Catherine Brua,Nathalie Silvestre,Renaud Morin,Johann Foloppe,Annie Findeli,Doris Schmitt,Sokunthea Top,Jean-Michel Lagarde,Philippe Erbs,Sandrine Kappler-Gratias

doi:10.3390/biomedicines8120543

Abstract

As a live biologic agent, oncolytic vaccinia virus has the ability to target and selectively amplify at tumor sites. We have previously reported that deletion of thymidine kinase and ribonucleotide reductase genes in vaccinia virus can increase the safety and efficacy of the virus. Here, to allow direct visualization of the viral genome in living cells, we incorporated the ANCH target sequence and the OR3-Santaka gene in the double-deleted vaccinia virus. Infection of human tumor cells with ANCHOR3-tagged vaccinia virus enables visualization and quantification of viral genome dynamics in living cells. The results show that the ANCHOR technology permits the measurement of the oncolytic potential of the double deleted vaccinia virus. Quantitative analysis of infection kinetics and of viral DNA replication allow rapid and efficient identification of inhibitors and activators of oncolytic activity. Our results highlight the potential application of the ANCHOR technology to track vaccinia virus and virtually any kind of poxvirus in living cells.

Highlights

Oncolytic virotherapy has recently been recognized as a promising therapeutic approach for cancer treatment
The ANCH sequence was inserted into the I4L locus of the vaccinia virus (VACV) genome
MRC-5 cells wereattreated with increasing concentrations of vorinostat and immediately infected imaging (HCI) ANCHOR

Summary

Introduction

Oncolytic virotherapy has recently been recognized as a promising therapeutic approach for cancer treatment. Compared with other oncolytic viruses, vaccinia virus (VACV) has many unique advantages as a therapeutic vector: it has a high transduction efficiency and a rapid replication cycle, producing mature progeny in just 6 h [2]. It is very safe, replication of VACV is exclusively cytoplasmic, eliminating the risk of chromosomal integration [3]. Replication of VACV is exclusively cytoplasmic, eliminating the risk of chromosomal integration [3] It has a broad-spectrum infectivity and tumor tropism, VACV can infect almost all types of tumor cells [4]. It has a large genome that can accept large foreign DNA inserts of up Biomedicines 2020, 8, 543; doi:10.3390/biomedicines8120543 www.mdpi.com/journal/biomedicines

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