Identification of a new membrane-permeable inhibitor against inositol-1,4,5-trisphosphate-3-kinase A

Biochem Biophys Res Commun. 2013 Sep 20;439(2):228-34. doi: 10.1016/j.bbrc.2013.08.053. Epub 2013 Aug 24.

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.

Keywords: Cellular uptake; High-throughput screening; ITPKA; ITPKA-inhibitor; InsP(3); Metastasis; Mixed inhibition type.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Cell Membrane Permeability
  • Drug Evaluation, Preclinical
  • High-Throughput Screening Assays
  • Humans
  • Phosphotransferases (Alcohol Group Acceptor) / antagonists & inhibitors*
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism*
  • Protein Kinase Inhibitors / chemistry*
  • Protein Kinase Inhibitors / pharmacokinetics*
  • Protein Kinase Inhibitors / pharmacology
  • Small Molecule Libraries / chemistry*
  • Small Molecule Libraries / pharmacokinetics*
  • Small Molecule Libraries / pharmacology

Substances

  • Protein Kinase Inhibitors
  • Small Molecule Libraries
  • Phosphotransferases (Alcohol Group Acceptor)
  • Inositol 1,4,5-trisphosphate 3-kinase