Related Experiment Video
Updated: Aug 24, 2026

Studying TGF-β Signaling and TGF-β-induced Epithelial-to-mesenchymal Transition in Breast Cancer and Normal Cells
Published on: October 27, 2020
Suppression of matrix metalloproteinase-9 transcription by transforming growth factor-beta is mediated by a nuclear
Kenji Ogawa1, Feifei Chen, Chenzhong Kuang
1Department of Medical and Molecular Genetics, Walther Oncology Center, Indiana University School of Medicine and the Walther Cancer Institute, Indianapolis, IN 46202, USA.
Abstract:
TGF-beta (transforming growth factor-beta) plays a critical role in modulating the inflammatory response and other biological processes through its regulation of the production of MMPs (matrix metalloproteinases). In both Mono-Mac-6 and RAW264.7 monocyte/macrophage cells, TGF-beta abrogated lipopolysaccharide-induced increases in the enzymic activity and mRNA level of MMP-9. A fragment of the human MMP-9 promoter was used to characterize its regulation by TGF-beta signalling. In RAW264.7 cells, TGF-beta or its downstream signalling protein, Smad3 (Sma- and Mad-related protein 3), inhibited lipopolysaccharide-stimulated promoter activity. The suppressive activity of TGF-beta on the MMP-9 promoter was abrogated by an inhibitory Smad, Smad7. The MMP-9 promoter contains a putative TIE (TGF-beta inhibitory element). However, neither mutation nor deletion of the TIE had any effect on the inhibitory activity of TGF-beta on MMP-9 transcription, indicating that the consensus TIE is not required for this effect of TGF-beta. Analysis using a series of deletion mutants of the MMP-9 promoter revealed that a region containing a consensus NF-kappaB (nuclear factor-kappaB) site is required for the basal activity and TGF-beta-mediated suppression of the promoter. Mutation of the putative NF-kappaB site not only markedly reduced the basal transcriptional activity of the promoter, but also abrogated the responsiveness of the promoter to TGF-beta. In addition, a minimal promoter containing one copy of the NF-kappaB sequence was responsive to TGF-beta treatment. Furthermore, an electrophoretic mobility shift assay was performed with the nuclear extracts from RAW264.7 cells, and it was found that TGF-beta treatment did not disrupt the binding of NF-kappaB p50 and p65 proteins to the NF-kappaB sequence. Taken together, these studies indicate that the NF-kappaB site is indispensable for the suppressive activity of TGF-beta in the regulation of MMP-9 transcription.
Related Concept Videos
TGF - β Signaling Pathway
NF-κB-dependent Signaling Pathway
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...
Co-activators and Co-repressors
Role of Matrix Metalloproteases in Degradation of ECM
A...
Eukaryotic Transcription Inhibitors
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
MAPK Signaling Cascades

