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Updated: Apr 16, 2026

An In Vitro Dormancy Model of Estrogen-sensitive Breast Cancer in the Bone Marrow: A Tool for Molecular Mechanism Studies and Hypothesis Generation
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An In Vitro Dormancy Model of Estrogen-sensitive Breast Cancer in the Bone Marrow: A Tool for Molecular Mechanism Studies and Hypothesis Generation

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Targeting rho guanine nucleotide exchange factor ARHGEF5/TIM with auto-inhibitory peptides in human breast cancer

Ou Huang1, Dandan Wu, Feiyan Xie

  • 1Department of Surgery, Ruijin Hospital, Medical School of Shanghai Jiaotong University, Shanghai, 200025, China.

Amino Acids
|March 7, 2015
PubMed

Insights

Researchers optimized ARHGEF5/TIM

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Oncology

Background:

  • ARHGEF5/TIM is an oncogenic protein overexpressed in human breast cancer and other tumors.
  • It belongs to Rho guanine nucleotide exchange factors, activating Rho GTPases.
  • TIM's activity is auto-inhibited by an N-terminal helix interacting with its Dbl homology (DH) domain.

Purpose of the Study:

  • To target the TIM DH domain using modified versions of its auto-inhibitory helix.
  • To optimize the physicochemical properties and structural conformation of the auto-inhibitory helix.
  • To investigate the binding affinity of modified peptides to the TIM DH domain.

Main Methods:

  • Bioinformatics techniques were employed to analyze intramolecular interactions.
  • Peptide optimization focused on physicochemical properties and structural conformation.
  • Affinity assays were conducted to determine binding strength (dissociation constants).

Main Results:

  • Two modified peptides, DALYEEYNLVV and EVLYEEYQLVV, showed significant binding to the TIM DH domain.
  • Dissociation constants (Kd) were determined as 0.35 µM and 2 µM, respectively.
  • Structural analysis indicated that charge neutralization and electrostatic interactions enhance complex stability.

Conclusions:

  • Modified auto-inhibitory helices can effectively target the ARHGEF5/TIM DH domain.
  • Optimized peptides demonstrate strong binding affinity, suggesting therapeutic potential.
  • Understanding these interactions aids in designing inhibitors for ARHGEF5/TIM in cancer treatment.

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