Spred2 inhibits TGF-beta1-induced urokinase type plasminogen activator expression, cell motility and epithelial mesenchymal transition

Int J Cancer. 2010 Jul 1;127(1):77-85. doi: 10.1002/ijc.25045.

Abstract

TGF-beta1 is a potent inductor of malignance in cancer cells. TGF-beta1 stimulates the expression of extracellular matrix degrading proteases, cell migration and it is also involved in the epithelial-mesenchymal transition (EMT). In the present work, we analyzed the role of Spred2 in the urokinase-type plasminogen activator (uPA) stimulation, EMT and cell migration by TGF-beta1. We found that both the expression of mRNA and the protein level of Spred2 were lower in transformed keratinocytes PDV compared with immortalized keratinocytes MCA-3D. The transient ectopic expression of Spred2 in PDV cells inhibited the TGF-beta1-transactivated SRE-Luc reporter which is related with the ERK1,2 signal. The stable ectopic expression of Spred2 in PDV cells (SP cells) led to the loss of ERK 1,2 activation by TGF-beta1, although Smad2 activation was not affected, and the knockdown of Spred2 enhanced the activation of ERK1,2 signal by TGF-beta1. The increment of uPA expression induced by TGF-beta1 was suppressed in SP cells. In contrast, the stimulus on PAI-1 expression was not affected and comparable to parental PDV cells. SP cells under TGF-beta1 treatment were unable to display the EMT, since the overexpression of Spred2 abolished the TGF-beta1-induced disruption of the E-cadherin cell to cell interactions, reorganization of the actin cytoskeleton and upregulation of the mesenchymal marker vimentin. Finally, SP cells could not respond to the TGF-beta1 stimulus on cell migration. Taken together, the data in the present study suggests that Spred2 is a regulator of TGF-beta1-induced malignance in transformed keratinocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Movement / physiology*
  • DNA Primers
  • Enzyme Activation
  • Epithelial Cells / cytology*
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Fluorescent Antibody Technique
  • Gene Knockdown Techniques
  • Humans
  • Mesoderm / cytology*
  • Repressor Proteins / genetics
  • Repressor Proteins / physiology*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transforming Growth Factor beta1 / physiology*
  • Urokinase-Type Plasminogen Activator / metabolism*

Substances

  • DNA Primers
  • Repressor Proteins
  • SPRED2 protein, human
  • Transforming Growth Factor beta1
  • Extracellular Signal-Regulated MAP Kinases
  • Urokinase-Type Plasminogen Activator