Selective inhibition of TGF-β responsive genes by Smad-interacting peptide aptamers from FoxH1, Lef1 and CBP

Qiqi Cui, Sang Kyun Lim, Bryan Zhao, Francis Michael Hoffmann

Research output: Contribution to journalArticle

46 Scopus citations

Abstract

Transforming growth factor beta (TGF-β) stimulation results in the assembly of Smad-containing protein complexes that mediate activation or repression of TGF-β responsive genes. To determine if disruption of specific Smad protein-protein interactions would selectively inhibit responses to TGF-/β or generally interfere with Smad-dependent signaling, we developed three Smad-binding peptide aptamers by introducing Smad interaction motifs from Smad-binding proteins CBP, FoxH1 and Lef1 into the scaffold protein E. coli thioredoxin A (Trx). All three classes of aptamers bound to Smads by GST pulldown assays and co-immunoprecipitation from mammalian cells. Expression of the aptamers in HepG2 cells did not generally inhibit Smad-dependent signaling as evaluated using seven TGF-β responsive luciferase reporter genes. The Trx-xFoxH1b aptamer inhibited TGF-β-induced expression from a reporter dependent on the Smad-FoxH1 interaction, A3-lux, by 50%. Trx-xFoxH1b also partially inhibited two reporters not dependent on a Smad-FoxH1 interaction, 3TP-lux and Twntop, and endogenous PAI-1 expression. Trx-Lef1 aptamer only inhibited expression of the Smad-Lef1 responsive reporter gene TwnTop. The Trx-CBP aptamer had no significant effect on reporter gene expression. The results suggest that Smad-binding peptide aptamers can be developed to selectively inhibit TGF-β-induced gene expression.

Original languageEnglish (US)
Pages (from-to)3864-3874
Number of pages11
JournalOncogene
Volume24
Issue number24
DOIs
StatePublished - Jun 2 2005

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Keywords

  • FoxH1
  • Lef1
  • Peptide aptamer
  • Smad
  • TGF-beta

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research

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