Proteasome inhibitors decrease coxsackieviral RNA expression, viral protein synthesis and viral progeny release in HeLa cells.

<p>HeLa cells were sham-infected with PBS or infected with CVB3 in the presence or absence of MG132 or lactacystin. (A). Seven hours post-infection (pi), positive-stranded viral RNA was determined by <i>in situ</i> hybridization using anti-sense riboprobes for CVB3 (red). Cell nuclei were counterstained with hematoxylin (blue). (B). Cell lysates were collected at 7 h pi and immunoblotted with anti-VP1 and anti-β-actin (loading control) antibodies. (C). Medium was collected from CVB3-infected cells at 16 h pi and virus titer was determined by plaque assays. The data shown are mean±SE (standard errors) from three independent experiments. ^# p<0.001 as compared to CVB3 infection without treatment. (D). Cell viability assay was performed at 16 h pi by the MTS assay which measures mitochondrial function (mean±SE, n = 3). One hundred percent survival was defined as the level of MTS in sham-infected cells in the absence of MG132. ^# p<0.001 as compared to CVB3 infection only without MG132 treatment.