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Rac-specific guanine nucleotide exchange factor DOCK1 is a critical regulator of HER2-mediated breast cancer

Mélanie Laurin1, Jennifer Huber, Ariane Pelletier

  • 1Institut de Recherches Cliniques de Montréal, Montréal, QC, Canada H2W 1R7.

Proceedings of the National Academy of Sciences of the United States of America
|April 18, 2013
PubMed

Insights

Dedicator of Cytokinesis 1 (DOCK1) promotes HER2-driven breast cancer metastasis by activating Rac signaling. Inactivating DOCK1 reduces tumor growth and spread, offering a potential therapeutic target for metastatic breast cancer.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cell Biology

Background:

  • Metastasis of solid tumors is a primary cause of cancer mortality.
  • Understanding metastasis mechanisms is crucial for developing effective antimetastatic treatments.
  • Human epithelial growth factor receptor 2 (HER2) signaling plays a role in cancer progression.

Purpose of the Study:

  • To identify Rac activators downstream of HER2 that drive metastasis.
  • To investigate the role of Dedicator of Cytokinesis 1 (DOCK1) in HER2-mediated breast cancer metastasis.
  • To explore DOCK1 as a potential therapeutic target for limiting cancer spread.

Main Methods:

  • Correlative analysis of DOCK1 expression with patient survival in HER2(+) and basal breast cancer subtypes.
  • In vitro studies on DOCK1 interaction with HER2 and its effect on Rac activation and cell migration.
  • Development and analysis of a HER2 breast cancer mouse model with mammary-gland-specific DOCK1 inactivation.
  • Gene profiling to identify DOCK1-associated genes and signaling pathways.

Main Results:

  • High DOCK1 expression correlates with poorer survival in HER2(+) and basal breast cancer patients.
  • DOCK1 physically interacts with HER2, enhancing HER2-induced Rac activation and cell migration.
  • Mammary-gland-specific DOCK1 inactivation in a HER2 mouse model significantly reduced tumor growth and lung metastasis.
  • DOCK1 is essential for the activation of HER2 effectors c-JUN and STAT3.
  • A DOCK1-associated gene signature, including RTP4 and STAT1, can predict breast cancer outcomes.

Conclusions:

  • DOCK1-Rac signaling is a critical HER2 effector pathway driving breast cancer metastasis.
  • DOCK1 inactivation presents a promising therapeutic strategy to inhibit breast cancer progression and metastasis.
  • Specific DOCK1-associated genes may serve as independent biomarkers for predicting breast cancer patient outcomes.

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