Targets and tools: recent advances in the development of anti-HCV nucleic acids.

Hepatitis C virus (HCV), the major etiological agent of transfusion-associated non-A, non-B hepatitis, is a severe health problem affecting up to 3% of the world population. Since its identification in 1989, enormous efforts have been made to characterize the viral cycle. However, many details regarding the virus' penetration of hepatocytes, its replication and translation, and the assembling of virions remain unknown, mostly because of a lack of an efficient culture system. This has also hampered the development of fully effective antiviral drugs. Current treatments based on the combination of interferon and ribavirin trigger a sustained virological response in only 40% of infected individuals, thus the development of alternative therapeutic strategies is a major research goal. Nucleic acid based therapeutic agents may be of some potential in hepatitis C treatment. In recent years, much effort has gone into the improvement of DNA and RNA molecules as specific gene silencing tools. This review summarizes the state of the art in the development of new HCV therapies, paying special attention to those involving antisense oligonucleotides, aptamers, ribozymes, decoys and siRNA inhibitors. The identification of potential viral targets is also discussed.