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Updated: Sep 28, 2026

Studying TGF-β Signaling and TGF-β-induced Epithelial-to-mesenchymal Transition in Breast Cancer and Normal Cells
06:54

Studying TGF-β Signaling and TGF-β-induced Epithelial-to-mesenchymal Transition in Breast Cancer and Normal Cells

Published on: October 27, 2020

Autocrine transforming growth factor-beta signaling mediates Smad-independent motility in human cancer cells

Nancy Dumont1, Andrei V Bakin, Carlos L Arteaga

  • 1Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.

The Journal of Biological Chemistry
|November 8, 2002
PubMed

Insights

Transforming growth factor-beta (TGF-beta) can drive tumor cell motility through non-Smad pathways. Blocking TGF-beta receptor II impairs migration, suggesting novel therapeutic targets for breast cancer metastasis.

Area of Science:

  • Cell Biology
  • Molecular Oncology
  • Cancer Signaling

Background:

  • Transforming growth factor-beta (TGF-beta) is crucial for cell regulation.
  • Loss of TGF-beta sensitivity in cancer cells may promote motility via autocrine signaling.
  • Understanding these mechanisms is key to targeting cancer invasion.

Purpose of the Study:

  • To investigate the molecular mechanisms of autocrine TGF-beta in promoting breast cancer cell motility.
  • To determine the role of Smad-dependent and -independent pathways in TGF-beta-induced cell migration.

Main Methods:

  • Generated MDA-MB-231 breast cancer cells expressing a kinase-inactive TGF-beta receptor type II (T beta RII-K277R).
  • Assessed T beta RII-K277R expression, receptor association, and signaling pathway inhibition.
  • Utilized wound closure and transwell migration assays to evaluate cell motility.
  • Restored TGF-beta signaling using constitutively active TGF-beta type I receptor (ALK5(TD)) or Smad expression.

Main Results:

  • T beta RII-K277R expression successfully blocked TGF-beta signaling pathways.
  • Cells expressing T beta RII-K277R exhibited significantly impaired basal motility.
  • Motility was restored by ALK5(TD) but not by Smad2/4 or Smad3/4 reconstitution.
  • Restored motility correlated with increased Akt and ERK1/2 phosphorylation, independent of Smad2 phosphorylation.

Conclusions:

  • TGF-beta promotes breast cancer cell motility through Smad-independent signaling pathways.
  • Distinct signaling pathways may require different TGF-beta activation thresholds.
  • The phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase pathways are implicated in TGF-beta-driven motility.

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