Nox4 involvement in TGF-beta and SMAD3-driven induction of the epithelial-to-mesenchymal transition and migration of breast epithelial cells.

Autor: Boudreau HE; Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12441 Parklawn Drive, Rockville, MD, USA., Casterline BW, Rada B, Korzeniowska A, Leto TL
Jazyk: angličtina
Zdroj: Free radical biology & medicine [Free Radic Biol Med] 2012 Oct 01; Vol. 53 (7), pp. 1489-99. Date of Electronic Publication: 2012 Jun 19.
DOI: 10.1016/j.freeradbiomed.2012.06.016
Abstrakt: The epithelial-to-mesenchymal transition (EMT) is the development of increased cell plasticity that occurs normally during wound healing and embryonic development and can be coopted for cancer invasion and metastasis. TGF-beta induces EMT but the mechanism is unclear. Our studies suggest that Nox4, a member of the NADPH oxidase (Nox) family, is a source of reactive oxygen species (ROS) affecting cell migration and fibronectin expression, an EMT marker, in normal and metastatic breast epithelial cells. We found that TGF-beta induces Nox4 expression (mRNA and protein) and ROS generation in normal (MCF10A) and metastatic (MDA-MB-231) human breast epithelial cells. Conversely, cells expressing a dominant-negative form of Nox4 or Nox4-targeted shRNA showed significantly lower ROS production on TGF-beta treatment. Expression of a constitutively active TGF-beta receptor type I significantly increased Nox4 promoter activity, mRNA and protein expression, and ROS generation. Nox4 transcriptional regulation by TGF-beta was SMAD3 dependent based on the effect of constitutively active SMAD3 increasing Nox4 promoter activity, whereas dominant-negative SMAD3 or SIS3, a SMAD3-specific inhibitor, had the opposite effect. Furthermore, Nox4 knockdown, dominant-negative Nox4 or SMAD3, or SIS3 blunted TGF-beta induced wound healing and cell migration, whereas cell proliferation was not affected. Our experiments further indicate that Nox4 plays a role in TGF-beta regulation of fibronectin mRNA expression, based on the effects of dominant-negative Nox4 in reducing fibronectin mRNA in TGF-beta-treated MDA-MB-231and MCF10A cells. Collectively, these data indicate that Nox4 contributes to NADPH oxidase-dependent ROS production that may be critical for the progression of the EMT in breast epithelial cells, and thereby has therapeutic implications.
(Published by Elsevier Inc.)
Databáze: MEDLINE
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