Rapid Screening to Identify Antivirals against Persistent and Acute Coxsackievirus B3 Infection

Enteroviruses cause significant morbidity and mortality worldwide, and Coxsackievirus B3 (CVB3) is one of the most commonly reported. Coxsackieviruses establish persistent infection, characterized as infection that is not cleared from host cells generating a continuous infection. No antivirals targeting persistent or acute infection are available, and CVB3 may respond differently depending on the type of infection. Therefore, there is an urgent need for new antiviral drugs to combat acute and persistent CVB3 infection. We developed a system to study persistent CVB3 infection with pancreatic ductal cell line PANC-1, and we used an epithelial cell line, Vero-E6 cells, to study acute CVB3 infection. We maintained persistently infected cells for over a year. Now, in an effort to identify antivirals, using the National Institutes of Health's Developmental Therapeutics Program (DTP), we screened thousands of compounds for activity against acute and persistent CVB3 infection, and among the hits was Ro 5-3335, a 1,4-benzodiazepine nordazepam that acts as a RUNX1-CBFβ leukemia inhibitor. Ro 5-3335 has previously been reported to inhibit HIV-1 gene expression through interference with Tat-mediated transactivation. We confirmed Ro 5-3335's antiviral activity against CVB3 in both acute <i>and</i> persistent infection, in several cell types and at pharmacologically favorable conditions. We show that Ro 5-3335 has minimal cytotoxicity and is antiviral over several rounds of replication. We identified viral egress as a putative target. We also show efficacy against other RNA viruses, but it is ineffective against a model DNA virus. Overall, Ro 5-3335 is a promising antiviral that may target CVB3 infection.