Identification of a Water-Soluble Indirubin Derivative as Potent Inhibitor of Insulin-like Growth Factor 1 Receptor through Structural Modification of the Parent Natural Molecule

J Med Chem. 2017 Jun 22;60(12):4949-4962. doi: 10.1021/acs.jmedchem.7b00324. Epub 2017 Jun 6.

Abstract

Indirubins have been identified as potent ATP-competitive protein kinase inhibitors. Structural modifications in the 5- and 3'-position have been extensively investigated, but the impact of substituents in 5'-position is not equally well-studied. Here, we report the synthesis of new indirubin 3'- and 5'-derivatives in the search of water-soluble indirubins by introducing basic centers. Antiproliferative activity of all compounds in tumor cells was evaluated along with kinase inhibition of selected compounds. The results show the 3'-position to tolerate large substituents without compromising activity, whereas bulk and rigid substituents in 5'-position appear unfavorable. Screening molecular targets of water-soluble 3'-oxime ethers revealed 6ha as preferential inhibitor of insulin-like growth factor 1 receptor (IGF-1R) in a panel of 22 protein kinases and in cells. Consistently, 6ha inhibited tumor cell growth in the NCI 60 cell line panel and induced apoptosis. The results indicate that the 5'-position provides limited space for chemical modifications and identify 6ha as a potent water-soluble indirubin-based IGF-1R inhibitor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Cell Cycle Checkpoints / drug effects
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Chemistry Techniques, Synthetic
  • Drug Screening Assays, Antitumor / methods
  • Humans
  • Indoles / chemistry
  • Oximes / chemistry
  • Protein Kinase Inhibitors / chemical synthesis
  • Protein Kinase Inhibitors / chemistry*
  • Protein Kinase Inhibitors / pharmacology*
  • Receptor, IGF Type 1 / antagonists & inhibitors*
  • Receptor, IGF Type 1 / metabolism
  • Signal Transduction / drug effects
  • Solubility
  • Structure-Activity Relationship

Substances

  • Antineoplastic Agents
  • Indoles
  • Oximes
  • Protein Kinase Inhibitors
  • Receptor, IGF Type 1
  • indirubin