title: Identification of a new membrane-permeable inhibitor against inositol-1,4,5-trisphosphate-3-kinase A.
abstract: Ectopic expression of the neuron-specific inositol-1,4,5-trisphosphate-3-kinase A (ITPKA) in lung cancer cells increases their metastatic potential because the protein exhibits two actin regulating activities; it bundles actin filaments and regulates inositol-1,4,5-trisphosphate (InsP3)-mediated calcium signals by phosphorylating InsP3. Thus, in order to inhibit the metastasis-promoting activity of ITPKA, both its actin bundling and its InsP3kinase activity has to be blocked. In this study, we performed a high throughput screen in order to identify specific and membrane-permeable substances against the InsP3kinase activity. Among 341,44 small molecules, 237 compounds (0.7%) were identified as potential InsP3kinase inhibitors. After determination of IC50-values, the three compounds with highest specificity and highest hydrophobicity (EPPC-3, BAMB-4, MEPTT-3) were further characterized. Only BAMB-4 was nearly completely taken up by H1299 cells and remained stable after cellular uptake, thus exhibiting a robust stability and a high membrane permeability. Determination of the inhibitor type revealed that BAMB-4 belongs to the group of mixed type inhibitors. Taken together, for the first time we identified a highly membrane-permeable inhibitor against the InsP3kinase activity of ITPKA providing the possibility to partly inhibit the metastasis-promoting effect of ITPKA in lung tumor cells.
authors: Institut für Biochemie und Signaltransduktion, UKE Hamburg, Martinistr. 52, 20246 Hamburg, Germany.
authors: Dominik
authors: D
authors: Schröder
authors: Christoph
authors: C
authors: Rehbach
authors: Carola
authors: C
authors: Seyffarth
authors: Martin
authors: M
authors: Neuenschwander
authors: Jens V
authors: JV
authors: Kries
authors: Sabine
authors: S
authors: Windhorst
mesh_terms: D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability; D004353:Drug Evaluation, Preclinical; D057166:High-Throughput Screening Assays; D006801:Humans; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000737:chemistry* / Q000493:pharmacokinetics* / Q000494:pharmacology; D054852:Small Molecule Libraries / Q000737:chemistry* / Q000493:pharmacokinetics* / Q000494:pharmacology
chemical_list: D047428:Protein Kinase Inhibitors; D054852:Small Molecule Libraries; D017853:Phosphotransferases (Alcohol Group Acceptor); C051038:Inositol 1,4,5-trisphosphate 3-kinase
keywords: Cellular uptake; High-throughput screening; ITPKA; ITPKA-inhibitor; InsP(3); Metastasis; Mixed inhibition type