Stabilization of the Max Homodimer with a Small Molecule Attenuates Myc-Driven Transcription

Cell Chem Biol. 2019 May 16;26(5):711-723.e14. doi: 10.1016/j.chembiol.2019.02.009. Epub 2019 Mar 14.

Abstract

The transcription factor Max is a basic-helix-loop-helix leucine zipper (bHLHLZ) protein that forms homodimers or interacts with other bHLHLZ proteins, including Myc and Mxd proteins. Among this dynamic network of interactions, the Myc/Max heterodimer has crucial roles in regulating normal cellular processes, but its transcriptional activity is deregulated in a majority of human cancers. Despite this significance, the arsenal of high-quality chemical probes to interrogate these proteins remains limited. We used small molecule microarrays to identify compounds that bind Max in a mechanistically unbiased manner. We discovered the asymmetric polycyclic lactam, KI-MS2-008, which stabilizes the Max homodimer while reducing Myc protein and Myc-regulated transcript levels. KI-MS2-008 also decreases viable cancer cell growth in a Myc-dependent manner and suppresses tumor growth in vivo. This approach demonstrates the feasibility of modulating Max with small molecules and supports altering Max dimerization as an alternative approach to targeting Myc.

Keywords: Max; Myc; chemical probe; small molecule microarray; transcription.

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

  • Animals
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / chemistry
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / genetics
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism*
  • Cell Line
  • Dimerization
  • Disease Models, Animal
  • Humans
  • Lactams / chemical synthesis
  • Lactams / pharmacology*
  • Lactams / therapeutic use
  • Male
  • Mice
  • Mice, Inbred NOD
  • Mice, SCID
  • Neoplasms / drug therapy
  • Polycyclic Compounds / chemical synthesis
  • Polycyclic Compounds / pharmacology*
  • Polycyclic Compounds / therapeutic use
  • Promoter Regions, Genetic
  • Protein Binding
  • Proto-Oncogene Proteins c-myc / genetics*
  • Proto-Oncogene Proteins c-myc / metabolism
  • Rats
  • Repressor Proteins / chemistry
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Small Molecule Libraries / pharmacology*
  • Small Molecule Libraries / therapeutic use
  • Transcription, Genetic / drug effects*
  • Ultraviolet Rays

Substances

  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • KI-MS2-008
  • Lactams
  • MNT protein, human
  • Polycyclic Compounds
  • Proto-Oncogene Proteins c-myc
  • Repressor Proteins
  • Small Molecule Libraries