Small molecule modifiers of microRNA miR-122 function for the treatment of hepatitis C virus infection and hepatocellular carcinoma.

MicroRNAs are a recently discovered new class of important endogenous regulators of gene function. Aberrant regulation of microRNAs has been linked to various human diseases, most importantly cancer. Small molecule intervention of microRNA misregulation has the potential to provide new therapeutic approaches to such diseases. Here, we report the first small molecule inhibitors and activators of the liver-specific microRNA miR-122. This microRNA is the most abundant microRNA in the liver and is involved in hepatocellular carcinoma development and hepatitis C virus (HCV) infection. Our small molecule inhibitors reduce viral replication in liver cells and represent a new approach to the treatment of HCV infections. Moreover, small molecule activation of miR-122 in liver cancer cells selectively induced apoptosis through caspase activation, thus having implications in cancer chemotherapy. In addition to providing a new approach for the development of therapeutics, small molecule modifiers of miR-122 function are unique tools for exploring miR-122 biogenesis.