Transcriptional Inhibition of MicroRNA miR-122 by Small Molecules Reduces Hepatitis C Virus Replication in Liver Cells

MicroRNAs (miRNAs) are noncoding RNA molecules of 22–24
nucleotides that are estimated to regulate thousands of genes in humans,
and their dysregulation has been implicated in many diseases. MicroRNA-122
(miR-122) is the most abundant miRNA in the liver and has been linked
to the development of hepatocellular carcinoma and hepatitis C virus
(HCV) infection. Its role in these diseases renders miR-122 a potential
target for small-molecule therapeutics. Here, we report the discovery
of a new sulfonamide class of small-molecule miR-122 inhibitors from
a high-throughput screen using a luciferase-based reporter assay.
Structure–activity relationship (SAR) studies and secondary
assays led to the development of potent and selective miR-122 inhibitors.
Preliminary mechanism-of-action studies suggest a role in the promoter-specific
transcriptional inhibition of miR-122 expression through direct binding
to the liver-enriched transcription factor hepatocyte nuclear factor
4α. Importantly, the developed inhibitors significantly reduce
HCV replication in human liver cells.