Assay development and high-throughput screening of small molecular c-Abl kinase activators

J Biomol Screen. 2011 Jan;16(1):53-64. doi: 10.1177/1087057110384133. Epub 2010 Oct 11.

Abstract

A 2-step kinase assay was developed and used in a high-throughput screen (HTS) of more than 1 million compounds in an effort to identify c-Abl tyrosine kinase activators. This assay employed a 2-step phosphorylation reaction: in the first step, purified recombinant c-Abl was activated by incubating with compound in the presence of adenosine triphosphate (ATP). In the second step, the TAMRA-labeled IMAP Abltide substrate was added to allow phosphorylation of the substrate to occur. The assay was calibrated such that inactive c-Abl protein was activated by ATP alone to a degree that it not only demonstrated a measurable c-Abl activity but also maintained a robust assay window for screening. The screen resulted in 8624 primary hits with >30% response. Further analysis showed that 1024 had EC(50) <10 µM with a max % response of >50%. These hits were structurally and chemically diverse with possibly different mechanisms for activating c-Abl. In addition, selective hits were shown to be cell permeable and were able to induce c-Abl activation as determined by In-Cell Western (ICW) analysis of HEK-MSRII cells transduced with BacMam virus expressing full-length c-Abl.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Baculoviridae / genetics
  • Biological Assay
  • Drug Discovery
  • Enzyme Activators / pharmacology*
  • Genetic Vectors / genetics
  • HEK293 Cells
  • High-Throughput Screening Assays / methods*
  • Humans
  • Phosphorylation
  • Proto-Oncogene Proteins c-abl / agonists*
  • Proto-Oncogene Proteins c-abl / metabolism*
  • Small Molecule Libraries / pharmacology
  • Transfection

Substances

  • Enzyme Activators
  • Small Molecule Libraries
  • Adenosine Triphosphate
  • Proto-Oncogene Proteins c-abl