Genetic Screen for Hepatitis C virus (HCV) Protease Inhibitors

Invention A novel in vivo genetic screen for Hepatitis C virus (HCV) Protease Inhibitors has been developed based on the concerted co-expression of a reporter gene, recombinant Hepatitis C virus (HCV) non-structural 3 (NS3) protease and a potential inhibitor within a bacterial host. Potential inhibitors may be selected from a library of stabilized peptides or from a library of recombinant antibodies. The assay affords simple blue/white selection coupled with enrichment of cells expressing protease inhibitors by virtue of their faster growth on minimal media. Selected inhibitors of NS3 protease may be used as lead molecules for the development of anti-HCV therapies based on their ability to inhibit HCV replication and inhibition of disease progression.
The Need Hepatitis C virus (HCV) infection is a major world-wide health problem, causing chronic hepatitis, liver cirrhosis and primary liver cancer (HCC). Currently there is no anti HCV vaccine, and even the most effective HCV therapy with PEGylated interferon- in combination with ribavirin, a nucleoside analog with antiviral activity, is effective in <50% of infected individuals. The high frequency of treatment failure points to the need for more specific, less toxic and more active antiviral therapies for HCV.
Potential Applications o Selection of peptide inhibitors for the NS3 HCV protease

o Selection of non-peptide inhibitors for HCV protease

o The approach may be extended to screen for inhibitors of other proteases such as the HIV protease, caspases and others, as long as their recognition site may be contained in a sequential peptide sequence.
Advantages o Self-contained high through-put approach for selection of peptide inhibitors

o Simple one-step purification of selected peptides

o Small molecules can be simultaneously screened for toxicity and successful cell penetration using modified assay conditions where potential inhibitors are added to the culture media rather than co-expressed intracellularly.
Stage An in vitro fluorometric enzymatic assay for NS3 was developed. The assay has been tested with extracts obtained from natural Indian Siddha medicinal plants. Several NS3 serine protease inhibitors were identified The genetic screen for the isolation of NS3-inhibitors was tested with in vivo expressed single-chain antibodies (scFvs) from an antibody expression library. Some inhibitory scFvs were identified with this method results were confirmed by ELISA.
References Berdichevsky Y, Zemel R, Bachmatov L, Abramovich A, Koren R, Sathiyamoorthy P, Golan-Goldhirsh A, Tur-Kaspa R, Benhar I. A novel high throughput screening assay for HCV NS3 serine protease inhibitors. J Virol Methods. 2003 107:245-55
Patent no patent filed Tech Transfer Officer Ms. Irit Ben-Chlouch Office: +972-3-6406601 Fax: +972-3-6406675 Mail: [email protected]

Inventor(s): Itai Benhar, Ran Tur-Kaspa

Type of Offer: Licensing



« More Pharmaceutical Patents

---