4.6 Article

Hydrogen peroxide inhibits transforming growth factor-β1-induced cell cycle arrest by promoting Smad3 linker phosphorylation through activation of Akt-ERK1/2-linked signaling pathway

Journal

Publisher

ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.bbrc.2013.05.035

Keywords

H2O2; TGF-beta 1; Growth inhibition; Smad3 linker phosphorylation

Funding

  1. National R&D Program for Cancer Control, Ministry for Health and Welfare, Republic of Korea [1020420]
  2. National Research Foundation Grant of Korea (NRF)
  3. Ministry of Science, ICT & Future Planning [2009-0081 756]

Ask authors/readers for more resources

Hydrogen peroxide (H2O2) functions as a second messenger in growth factor receptor-mediated intracellular signaling cascade and is tumorigenic by virtue of its ability to promote cell proliferation; however, the mechanisms underlying the growth stimulatory action of H2O2 are less understood. Here we report an important mechanism for antagonistic effects of H2O2 on growth inhibitory response to transforming growth factor-beta 1 (TGF-beta 1). In Mv1Lu and HepG2 cells, pretreatment of H2O2 (0.05-0.2 mM) completely blocked TGF-beta 1-mediated induction of p15(INK4B) expression and increase of its promoter activity. Interestingly, H2O2 selectively suppressed the transcriptional activation potential of Smad3, not Smad2, in the absence of effects on TGF-beta 1-induced phosphorylation of the COOH-tail SSXS motif of Smad3 and its nuclear translocation. Mechanism studies showed that H2O2 increases the phosphorylation of Smad3 at the middle linker region in a concentration- and time-dependent manner and this effect is mediated by activation of extracellular signal-activated kinase 1/2 through Akt. Furthermore, expression of a mutant Smad3 in which linker phosphorylation sites were ablated significantly abrogated the inhibitory effects of H2O2 on TGF-beta 1-induced increase of p15(INK4B)-Luc reporter activity and blockade of cell cycle progression from G1 to S phase. These findings for the first time define H2O2 as a signaling molecule that modulate Smad3 linker phosphorylation and its transcriptional activity, thus providing a potential mechanism whereby H2O2 antagonizes the cytostatic function of TGF-beta 1. (C) 2013 Elsevier Inc. All rights reserved.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.6
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available