Discovery of tricyclic indoles that potently inhibit Mcl-1 using fragment-based methods and structure-based design

J Med Chem. 2015 May 14;58(9):3794-805. doi: 10.1021/jm501984f. Epub 2015 Apr 17.


Myeloid cell leukemia-1 (Mcl-1) is an antiapoptotic member of the Bcl-2 family of proteins that is overexpressed and amplified in many cancers. Overexpression of Mcl-1 allows cancer cells to evade apoptosis and contributes to the resistance of cancer cells to be effectively treated with various chemotherapies. From an NMR-based screen of a large fragment library, several distinct chemical scaffolds that bind to Mcl-1 were discovered. Here, we describe the discovery of potent tricyclic 2-indole carboxylic acid inhibitors that exhibit single digit nanomolar binding affinity to Mcl-1 and greater than 1700-fold selectivity over Bcl-xL and greater than 100-fold selectivity over Bcl-2. X-ray structures of these compounds when complexed to Mcl-1 provide detailed information on how these small-molecules bind to the target, which was used to guide compound optimization.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Crystallography, X-Ray
  • Heterocyclic Compounds, 3-Ring / chemical synthesis
  • Heterocyclic Compounds, 3-Ring / chemistry*
  • Heterocyclic Compounds, 3-Ring / pharmacology
  • Humans
  • Indoles / chemical synthesis
  • Indoles / chemistry*
  • Indoles / pharmacology
  • K562 Cells
  • Models, Molecular
  • Molecular Conformation
  • Myeloid Cell Leukemia Sequence 1 Protein / antagonists & inhibitors*
  • Myeloid Cell Leukemia Sequence 1 Protein / metabolism
  • Protein Binding
  • Structure-Activity Relationship
  • bcl-X Protein / chemistry
  • bcl-X Protein / metabolism


  • Heterocyclic Compounds, 3-Ring
  • Indoles
  • Myeloid Cell Leukemia Sequence 1 Protein
  • bcl-X Protein

Associated data

  • PDB/4ZBI