Designed BH3 peptides with high affinity and specificity for targeting Mcl-1 in cells

ACS Chem Biol. 2014 Sep 19;9(9):1962-8. doi: 10.1021/cb500340w. Epub 2014 Jul 23.

Abstract

Mcl-1 is overexpressed in many cancers and can confer resistance to cell-death signaling in refractory disease. Molecules that specifically inhibit Mcl-1 hold potential for diagnosing and disrupting Mcl-1-dependent cell survival. We selected three peptides from a yeast-surface display library that showed moderate specificity and affinity for binding to Mcl-1 over Bfl-1, Bcl-xL, Bcl-2, and Bcl-w. Specificity for Mcl-1 was improved by introducing threonine at peptide position 2e. The most specific peptide, MS1, bound Mcl-1 with 40-fold or greater specificity over four other human Bcl-2 paralogs. In BH3 profiling assays, MS1 caused depolarization in several human Mcl-1-dependent cell lines with EC50 values of ∼3 μM, contrasted with EC50 values of >100 μM for Bcl-2-, Bcl-xL-, or Bfl-1-dependent cell lines. MS1 is at least 30-fold more potent in this assay than the previously used Mcl-1 targeting reagent NoxaA BH3. These peptides can be used to detect Mcl-1 dependency in cells and provide leads for developing Mcl-1 targeting therapeutics.

Publication types

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

MeSH terms

  • Apoptosis Regulatory Proteins / chemistry
  • Apoptosis Regulatory Proteins / metabolism
  • Bcl-2-Like Protein 11
  • Cell Line / drug effects
  • Cell Surface Display Techniques / methods
  • Fluorescence Polarization
  • Humans
  • Membrane Proteins / chemistry
  • Membrane Proteins / metabolism
  • Minor Histocompatibility Antigens
  • Molecular Targeted Therapy / methods*
  • Myeloid Cell Leukemia Sequence 1 Protein / antagonists & inhibitors
  • Myeloid Cell Leukemia Sequence 1 Protein / metabolism*
  • Peptide Fragments / chemistry
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism*
  • Peptides / chemistry*
  • Peptides / metabolism*
  • Peptides / pharmacology
  • Proto-Oncogene Proteins / chemistry
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Threonine / chemistry
  • Threonine / metabolism
  • bcl-X Protein / metabolism

Substances

  • Apoptosis Regulatory Proteins
  • BCL2-related protein A1
  • BCL2L1 protein, human
  • BCL2L11 protein, human
  • BCL2L2 protein, human
  • Bax protein (53-86)
  • Bcl-2-Like Protein 11
  • MCL1 protein, human
  • Membrane Proteins
  • Minor Histocompatibility Antigens
  • Myeloid Cell Leukemia Sequence 1 Protein
  • Peptide Fragments
  • Peptides
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-bcl-2
  • bcl-X Protein
  • Threonine