A virtual screening platform identifies chloroethylagelastatin a as a potential ribosomal inhibitor

Thomas R. Caulfield, Mayo Clinic in Jacksonville, Florida
Karen E. Hayes
Yushi Qiu, Mayo Clinic in Jacksonville, Florida
Mathew Coban, Mayo Clinic in Jacksonville, Florida
Joon Seok Oh, University of North Florida
Amy L. Lane, Mayo Clinic in Jacksonville, Florida
Takehiko Yoshimitsu, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
Lori Hazlehurst, West Virginia University
John A. Copland, Mayo Clinic in Jacksonville, Florida
Han W. Tun, Mayo Clinic in Jacksonville, Florida

Abstract

Chloroethylagelastatin A (CEAA) is an analogue of agelastatin A (AA), a natural alkaloid derived from a marine sponge. It is under development for therapeutic use against brain tumors as it has excellent central nervous system (CNS) penetration and pre-clinical therapeutic activity against brain tumors. Recently, AA was shown to inhibit protein synthesis by binding to the ribosomal A-site. In this study, we developed a novel virtual screening platform to perform a comprehensive screening of various AA analogues showing that AA analogues with proven therapeutic activity including CEAA have significant ribosomal binding capacity whereas therapeutically inactive analogues show poor ribosomal binding and revealing structural fingerprint features essential for drug-ribosome interactions. In particular, CEAA was found to have greater ribosomal binding capacity than AA. Biological tests showed that CEAA binds the ribosome and contributes to protein synthesis inhibition. Our findings suggest that CEAA may possess ribosomal inhibitor activity and that our virtual screening platform may be a useful tool in discovery and development of novel ribosomal inhibitors.