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Induction and Analysis of Epithelial to Mesenchymal Transition
10:37

Induction and Analysis of Epithelial to Mesenchymal Transition

Published on: August 27, 2013

SIP1/ZEB2 induces EMT by repressing genes of different epithelial cell-cell junctions

Cindy Vandewalle1, Joke Comijn, Bram De Craene

  • 1Unit of Molecular and Cellular Oncology, Department for Molecular Biomedical Research, VIB-Ghent University, Belgium.

Nucleic Acids Research
|November 30, 2005
PubMed

Insights

Smad Interacting Protein 1 (SIP1) drives epithelial mesenchymal transition (EMT) by repressing key cell junctional proteins. This transcription factor coordinates gene silencing, promoting a dedifferentiated state in human epithelial cells.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Cancer Research

Background:

  • Smad Interacting Protein 1 (SIP1), a deltaEF-1 family transcription factor, is linked to epithelial mesenchymal transitions (EMT).
  • SIP1 expression is observed in certain breast cancers and gastric carcinomas, correlating inversely with E-cadherin levels.
  • EMT is a developmental process where cells lose epithelial characteristics and gain migratory mesenchymal traits.

Purpose of the Study:

  • To investigate the role of SIP1 in inducing morphological changes from epithelial to mesenchymal phenotypes in human cells.
  • To identify the downstream targets of SIP1 and elucidate the mechanism of transcriptional repression.
  • To understand how SIP1 contributes to the dedifferentiated state during EMT.

Main Methods:

  • Induction of SIP1 expression in human epithelial cells.
  • Analysis of morphological changes and cell junctional protein expression.
  • Quantitative assessment of mRNA levels for cell junctional proteins.
  • Luciferase reporter assays and chromatin immunoprecipitation to study promoter activity and direct binding of SIP1.

Main Results:

  • SIP1 expression induced a clear morphological shift from epithelial to mesenchymal phenotype.
  • SIP1 repressed multiple cell junctional proteins, including E-cadherin, and their corresponding mRNA levels.
  • SIP1 was shown to directly repress the transcription of genes encoding tight junction, desmosome, and gap junction proteins.
  • Evidence suggests a general mechanism of repression mediated by SIP1-binding sites on target gene promoters.

Conclusions:

  • SIP1 acts as a transcriptional repressor that orchestrates the downregulation of junctional protein genes during EMT.
  • SIP1 directly mediates the repression of these genes, contributing to the dedifferentiated state.
  • The findings highlight a coordinated mechanism by which SIP1 drives epithelial dedifferentiation through transcriptional control.

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