Description
In this report we utilized zebrafish (Danio rerio) embryos in a phenotypical high-content screen (HCS) to identify novel leads in a cancer drug discovery program. We initially validated our HCS model using the flavin adenosine dinucleotide (FAD) containing endoplasmic reticulum (ER) enzyme, endoplasmic reticulum oxidoreductase (ERO1) inhibitor EN460. EN460 showed a dose response effect on the embryos with a dose of 10muM being significantly lethal during early embryonic development. The HCS campaign which employed a small library identified a promising lead compound, a naphthyl-benzoic acid derivative coined compound 1 which had significant dosage and temporally dependent effects on notochord and muscle development in zebrafish embryos. Screening a 369 kinase member panel we show that compound 1 is a PIM3 kinase inhibitor (IC50=4.078muM) and surprisingly a DAPK1 kinase agonist/activator (EC50=39.525muM). To our knowledge this is the first example of a small molecule activating DAPK1 kinase. We provide a putative model for increased phosphate transfer in the ATP binding domain when compound 1 is virtually docked with DAPK1. Our data indicate that observable phenotypical changes can be used in future zebrafish screens to identify compounds acting via similar molecular signaling pathways.
Subject
*Cancer; *Compound library; *Kinase; *Notochord; *Phenotypic screen; *Somites; *Zebrafish; Animals; Antineoplastic Agents/chemistry/pharmacology; Antitumor/methods; Benzoic Acid/chemistry/pharmacology; Death-Associated Protein Kinases/metabolism; Drug Discovery/*methods; Drug Screening Assays; Embryo; Enzyme Activation/drug effects; Enzyme Activators/*chemistry/*pharmacology; Neoplasms/drug therapy/enzymology; Nonmammalian/*drug effects/enzymology; Protein Kinase Inhibitors/*chemistry/*pharmacology; Protein-Serine-Threonine Kinases/antagonists & inhibitors/metabolism; Zebrafish Proteins/antagonists & inhibitors/metabolism; Zebrafish/*embryology