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Thioflavin S inhibits hepatitis C virus RNA replication and the viral helicase with a novel mechanism
Author(s) -
Frick David N,
Belon Craig A
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.lb202
Subject(s) - rna , replicon , thioflavin , ns3 , rna helicase a , microbiology and biotechnology , virology , hepatitis c virus , biology , chemistry , viral replication , helicase , virus , dna , biochemistry , gene , medicine , disease , pathology , alzheimer's disease , plasmid
The NCI mechanistic diversity set (827 compounds) was screened a with a molecular beacon helicase assay to identify inhibitors of the helicase encoded by the hepatitis C virus (HCV). All of the small molecule inhibitors identified also interacted with the DNA substrate in a direct binding assay except one, Thioflavin S. When administered to cells that have been stably transfected with a subgenomic HCV replicon Thioflavin S was not toxic, and it decreased the amount of positive sense HCV RNA by 21%. Thioflavin S was more effective when it was administered with RNA upon transfection, decreasing both positive and negative sense RNA by 42% and 85% respectively in 6 days when present at 50 μM. These decreases in HCV RNA after transfection were concentration dependent and similar to those seen when interferon was administered in the same manner to the same cells. Thioflavin S inhibited NS3 catalyzed DNA unwinding with an IC50 of 13 μM, ATP hydrolysis with and IC50 of 39 μM, and peptide cleavage by 40% when present at 15 μM, but unlike other well‐characterized helicase inhibitors, the compound did not compete with either RNA or ATP for known binding sites. The compound inhibits the NS3 protein from various HCV genotypes, Japanese encephalitis virus, and Dengue Virus, but has no discernable effects on related proteins. This study was supported by NIH grants AI052395, MH085690, & AI088001.