Identification and validation of novel small molecule disruptors of HuR-mRNA interaction

ACS Chem Biol. 2015 Jun 19;10(6):1476-84. doi: 10.1021/cb500851u. Epub 2015 Mar 17.

Abstract

HuR, an RNA binding protein, binds to adenine- and uridine-rich elements (ARE) in the 3'-untranslated region (UTR) of target mRNAs, regulating their stability and translation. HuR is highly abundant in many types of cancer, and it promotes tumorigenesis by interacting with cancer-associated mRNAs, which encode proteins that are implicated in different tumor processes including cell proliferation, cell survival, angiogenesis, invasion, and metastasis. Drugs that disrupt the stabilizing effect of HuR upon mRNA targets could have dramatic effects on inhibiting cancer growth and persistence. In order to identify small molecules that directly disrupt the HuR-ARE interaction, we established a fluorescence polarization (FP) assay optimized for high throughput screening (HTS) using HuR protein and an ARE oligo from Musashi RNA-binding protein 1 (Msi1) mRNA, a HuR target. Following the performance of an HTS of ∼6000 compounds, we discovered a cluster of potential disruptors, which were then validated by AlphaLISA (Amplified Luminescent Proximity Homogeneous Assay), surface plasmon resonance (SPR), ribonucleoprotein immunoprecipitation (RNP IP) assay, and luciferase reporter functional studies. These compounds disrupted HuR-ARE interactions at the nanomolar level and blocked HuR function by competitive binding to HuR. These results support future studies toward chemical probes for a HuR function study and possibly a novel therapy for HuR-overexpressing cancers.

Publication types

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

MeSH terms

  • Binding Sites / drug effects
  • Cell Line
  • Cell Survival / drug effects
  • ELAV-Like Protein 1 / antagonists & inhibitors*
  • ELAV-Like Protein 1 / genetics
  • ELAV-Like Protein 1 / metabolism
  • Epithelial Cells / cytology
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism
  • Fibroblasts / cytology
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Gene Expression Regulation
  • Genes, Reporter
  • HCT116 Cells
  • High-Throughput Screening Assays
  • Humans
  • Immunoprecipitation
  • Luciferases / genetics
  • Luciferases / metabolism
  • Molecular Probes / chemistry
  • Nerve Tissue Proteins / antagonists & inhibitors*
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Protein Binding / drug effects
  • RNA, Messenger / antagonists & inhibitors*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA-Binding Proteins / antagonists & inhibitors*
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism
  • Response Elements / drug effects*
  • Signal Transduction
  • Small Molecule Libraries / chemistry
  • Small Molecule Libraries / pharmacology*
  • Surface Plasmon Resonance

Substances

  • ELAV-Like Protein 1
  • ELAVL1 protein, human
  • MSI1 protein, human
  • Molecular Probes
  • Nerve Tissue Proteins
  • RNA, Messenger
  • RNA-Binding Proteins
  • Small Molecule Libraries
  • Luciferases