PKR-NF-κB Pathway Upstream of IFN-β Induction Is Dysregulated in Oncolytic Sindbis Virus-infected HeLa Cells.

Abstract

Sindbis virus (SINV) is a naturally occurring oncolytic virus that kills cancer cells and is less harmful to normal cells. In this study, a recombinant SINV, which expressed green and blue fluorescent proteins, was used to precisely analyze SINV infection and replication. Antiviral responses, including IFN-β mRNA, protein kinase R (PKR), NF-B, and caspase 3/7, were analyzed in SINV-infected cancerous HeLa cells and normal human fibroblast TIG-1-20 cells. SINV could infect, replicate, and proliferate both in HeLa and TIG-1-20 cells, causing lytic infection only in HeLa cells. SINV grew preferentially in HeLa cells causing remarkable apoptosis. IFN-β mRNA expression was suppressed in SINV-infected HeLa cells compared to that in TIG-1-20 cells. Further analyses of PKR and NF-B upstream of IFN-β induction revealed that the compromised response in the PKR-NF-B pathway during early infection coincided with IFN induction suppression in HeLa cells. Dysregulation of PKR in HeLa cells is the determinant of SINV oncolysis.