High-throughput cell-based screening for hepatitis C virus NS3/4A protease inhibitors

Area of Science:

• Virology
• Biochemistry
• Drug Discovery

Background:

• Hepatitis C virus (HCV) nonstructural (NS)3/4A protease is crucial for viral maturation and a target for antiviral therapies.
• Previous attempts to develop NS3/4A protease inhibitors have not yet yielded successful anti-HCV treatments.
• A reporter system, EG(delta4AB)SEAP, was previously developed to monitor NS3/4A protease activity within cells.

Purpose of the Study:

• To generate and characterize a stable cell line for monitoring Hepatitis C virus (HCV) NS3/4A protease activity.
• To validate the utility of this cell line for drug screening against HCV.
• To establish a high-throughput screening method for identifying novel anti-HCV compounds.

Main Methods:

• Generation of a stable cell line (293EEG(delta4AB)SEAP-NS3/4A) constitutively expressing the EG(delta4AB)SEAP reporter and NS3/4A protease.
• Validation of the reporter assay using BILN 2061, a known NS3 protease inhibitor.
• Assessment of the cell line's performance in a 96-well plate format for screening.

Main Results:

• The stable cell line successfully expresses both the reporter and the viral protease.
• The reporter assay demonstrated high efficiency in reflecting NS3/4A proteolytic activity.
• The cell-based assay achieved a Z factor >0.6, indicating suitability for high-throughput screening.
• Validation with BILN 2061 confirmed the assay's ability to detect protease inhibition.

Conclusions:

• The developed stable cell line is a robust tool for studying NS3/4A protease activity.
• This cell-based assay facilitates high-throughput screening of chemical libraries for potential anti-HCV drug discovery.
• The system offers a promising avenue for identifying novel therapeutic agents against Hepatitis C virus.