Abstract 4776: From in-silico screening to anti-cancer activity: The discovery of a potent inhibitor targeting the JNK-JIP interaction

Abstract

Abstract The JNK signaling pathway is related to the pathogenesis of several diseases, including cancer (JNK2 selective inhibitors have been reported as potential suppressor of breast cancer cell migration). The JNK-JIP interaction represents an attractive target for the selective inhibition of JNK-mediated signaling. Herein, we applied a Hybrid Structure-Based Virtual-Screening (VS) workflow based on a combination of 3D shape and electrostatic similarity with GOLD (Genetic Optimization in Ligand Docking) and FRED (Fast Rigid Exhaustive Docking) docking screening techniques to discover novel scaffolds for small ATP-Independent JNK inhibitor targeting the JNK-JIP interaction. The starting point for the VS here was BI78-D3, which has been reported as the first inhibitor targeting JNK-JIP interaction. Out of 750 compounds representing the highest ranked by VS of NCI (National Cancer Institute) Diversity Set (∼250,000 compounds), 352 were tested by in-vitro cell-free kinase assay. The Ability of the used VS protocol to identify selective JNK inhibitors has been tested by screening those 352 compounds against five different kinases. The two tested atypical kinases (eEF2K and TrpM7) which has the least structure similarity with MAP kinases showed very limited inhibition if compared to JNK1 and JNK2, surprisingly, ERK2 and P38-alpha, the two structurally similar to JNK, showed similar results to the alpha kinases. This has been confirmed by an enrichment experiment that has been done using 350 compounds that randomly selected from the same library without employment of virtual screening, these compounds showed very similar inhibition pattern to both JNK and TrpM7 due to the loss of JNK selectivity that established by employment of VS. To validate the efficiency of the used VS protocol to identify inhibitors that bind the JIP-JNK binding site, we developed a displacement assay using FITC (Fluorescein-isothiocyanate) labeled-JIP peptide. Most of the compounds that inhibited JNK kinase activity more than 50% were able to decrease binding of the labeled JIP-peptide to JNK, suggesting the successful targeting of the substrate-binding site of JNK by the identified inhibitors. In summary, the used VS protocol identified novel scaffolds for JNK selective small ATP-Independent inhibitors targeting the JNK-JIP interaction. These compounds will be potential candidates as inhibitors of breast cancer cell migration. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4776. doi:1538-7445.AM2012-4776