Small interfering RNA against the 2C genomic region of coxsackievirus B3 exerts potential antiviral effects in permissive HeLa cells.

Coxsackievirus B3 (CVB3) is the most important causal agent of viral heart muscle disease, but no specific antiviral drug is currently available. Small interfering RNA (siRNA) has been used as an antiviral therapeutic strategy via posttranscriptional gene silencing. In this study, eleven siRNAs were designed to target seven distinct regions of the CVB3 genome including VP1, VP2, VP3, 2A, 2C, 3C, and 3D. All of the siRNAs were individually transfected into HeLa cells, which were subsequently infected with CVB3. The impacts of RNA interference (RNAi) on viral replication were evaluated using five measures: cytopathic effect (CPE), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, 50% tissue culture infectious dose (TCID(50)), real-time RT-PCR, and Western blot. Five of the eleven siRNAs were highly efficient at inhibiting viral replication. This was especially true for siRNA-5, which targeted the ATPase 2C. However, antiviral activity varied significantly among siRNA-9, -10, and -11 even though that they all targeted the 3D region. Our results revealed several effective targets for CVB3 silencing, and provided evidence that sequences except CRE within the 2C region may also be potential targets for CVB3-specific siRNAs design. These data supported a potential role of RNA interference in future antiviral intervention therapies.