title: Discovery of diverse small molecule chemotypes with cell-based PKD1 inhibitory activity.
abstract: Protein kinase D (PKD) is a novel family of serine/threonine kinases regulated by diacylglycerol, which is involved in multiple cellular processes and various pathological conditions. The limited number of cell-active, selective inhibitors has historically restricted biochemical and pharmacological studies of PKD. We now markedly expand the PKD1 inhibitory chemotype inventory with eleven additional novel small molecule PKD1 inhibitors derived from our high throughput screening campaigns. The in vitro IC(50)s for these eleven compounds ranged in potency from 0.4 to 6.1 µM with all of the evaluated compounds being competitive with ATP. Three of the inhibitors (CID 1893668, (1Z)-1-(3-ethyl-5-methoxy-1,3-benzothiazol-2-ylidene)propan-2-one; CID 2011756, 5-(3-chlorophenyl)-N-[4-(morpholin-4-ylmethyl)phenyl]furan-2-carboxamide; CID 5389142, (6Z)-6-[4-(3-aminopropylamino)-6-methyl-1H-pyrimidin-2-ylidene]cyclohexa-2,4-dien-1-one) inhibited phorbol ester-induced endogenous PKD1 activation in LNCaP prostate cancer cells in a concentration-dependent manner. The specificity of these compounds for PKD1 inhibitory activity was supported by kinase assay counter screens as well as by bioinformatics searches. Moreover, computational analyses of these novel cell-active PKD1 inhibitors indicated that they were structurally distinct from the previously described cell-active PKD1 inhibitors while computational docking of the new cell-active compounds in a highly conserved ATP-binding cleft suggests opportunities for structural modification. In summary, we have discovered novel PKD1 inhibitors with in vitro and cell-based inhibitory activity, thus successfully expanding the structural diversity of small molecule inhibitors available for this important pharmacological target.
authors: Department of Pharmacology, University of Virginia, Charlottesville, Virginia, United States of America. ers7g@virginia.edu
authors: Elizabeth R
authors: ER
authors: Sharlow
authors: Gabriela
authors: G
authors: Mustata Wilson
authors: David
authors: D
authors: Close
authors: Stephanie
authors: S
authors: Leimgruber
authors: Manuj
authors: M
authors: Tandon
authors: Robyn B
authors: RB
authors: Reed
authors: Tong Ying
authors: TY
authors: Shun
authors: Q Jane
authors: QJ
authors: Wang
authors: Peter
authors: P
authors: Wipf
authors: John S
authors: JS
authors: Lazo
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001667:Binding, Competitive; D020134:Catalytic Domain; D045744:Cell Line, Tumor; D017124:Conserved Sequence; D004305:Dose-Response Relationship, Drug; D055808:Drug Discovery / Q000379:methods*; D004789:Enzyme Activation / Q000187:drug effects; D057166:High-Throughput Screening Assays; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010703:Phorbol Esters / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D015203:Reproducibility of Results; D054852:Small Molecule Libraries / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D010703:Phorbol Esters; D047428:Protein Kinase Inhibitors; D054852:Small Molecule Libraries; D000255:Adenosine Triphosphate; C089212:protein kinase D; D011493:Protein Kinase C