Abstract
Protein kinase B/Akt (PKB) is an anti-apoptotic protein kinase that has strongly elevated activity in human malignancies. We therefore initiated a program to develop PKB inhibitors, "Aktstatins". We screened about 500 compounds for PKB inhibitors, using a radioactive assay and an ELISA assay that we established for this purpose. These compounds were produced as combinatorial libraries, designed using the structure of the selective PKA inhibitor H-89 as a starting point. We have identified a successful lead compound, which inhibits PKB activity in vitro and in cells overexpressing active PKB. The new compound shows reversed selectivity to H-89: In contrast to H-89, which inhibits PKA 70 times better than PKB, the new compound, NL-71-101, inhibits PKB 2.4-fold better than PKA. The new compound, but not H-89, induces apoptosis in tumor cells in which PKB is amplified. We have identified structural features in NL-71-101 that are significant for the specificity and that can be used for future development and optimization of PKB inhibitors.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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3T3 Cells
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Adenosine Triphosphate / chemistry
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Animals
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Apoptosis
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Binding, Competitive
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Calcium-Calmodulin-Dependent Protein Kinases / antagonists & inhibitors
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Calcium-Calmodulin-Dependent Protein Kinases / chemistry
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Cell Line
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Combinatorial Chemistry Techniques / methods
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Cyclic AMP-Dependent Protein Kinases / antagonists & inhibitors*
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Cyclic AMP-Dependent Protein Kinases / chemistry
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Enzyme Inhibitors / chemical synthesis*
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Enzyme Inhibitors / chemistry
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Glycogen Synthase Kinase 3
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Humans
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Isoquinolines / chemical synthesis*
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Isoquinolines / chemistry
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Mice
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Phosphorylation
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Protein Serine-Threonine Kinases / antagonists & inhibitors*
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Protein Serine-Threonine Kinases / chemistry
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Proto-Oncogene Proteins / antagonists & inhibitors*
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Proto-Oncogene Proteins / chemistry
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Proto-Oncogene Proteins c-akt
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Structure-Activity Relationship
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Substrate Specificity
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Sulfonamides*
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Tumor Cells, Cultured / enzymology
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Tumor Cells, Cultured / pathology
Substances
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Enzyme Inhibitors
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Isoquinolines
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NL-71-101
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Proto-Oncogene Proteins
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Sulfonamides
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Adenosine Triphosphate
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AKT1 protein, human
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-akt
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Cyclic AMP-Dependent Protein Kinases
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Calcium-Calmodulin-Dependent Protein Kinases
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Glycogen Synthase Kinase 3
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N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide