Transcription factor Nrf2 mediates an adaptive response to sulforaphane that protects fibroblasts in vitro against the cytotoxic effects of electrophiles, peroxides and redox-cycling agents.
Cast your vote
You can rate an item by clicking the amount of stars they wish to award to this item.
When enough users have cast their vote on this item, the average rating will also be shown.
Your vote was cast
Thank you for your feedback
Thank you for your feedback
AuthorsHiggins, Larry G.
Kelleher, Michael O.
Eggleston, Ian M.
Hayes, John D.
MetadataShow full item record
AbstractSulforaphane can stimulate cellular adaptation to redox stressors through transcription factor Nrf2. Using mouse embryonic fibroblasts (MEFs) as a model, we show herein that the normal homeostatic level of glutathione in Nrf2(-/-) MEFs was only 20% of that in their wild-type counterparts. Furthermore, the rate of glutathione synthesis following its acute depletion upon treatment with 3 micromol/l sulforaphane was very substantially lower in Nrf2(-/-) MEFs than in wild-type cells, and the rebound leading to a approximately 1.9-fold increase in glutathione that occurred 12-24 h after Nrf2(+/+) MEFs were treated with sulforaphane was not observed in Nrf2(-/-) fibroblasts. Wild-type MEFs that had been pre-treated for 24 h with 3 micromol/l sulforaphane exhibited between 1.4- and 3.2-fold resistance against thiol-reactive electrophiles, including isothiocyanates, alpha,beta-unsaturated carbonyl compounds (e.g. acrolein), aryl halides and alkene epoxides. Pre-treatment of Nrf2(+/+) MEFs with sulforaphane also protected against hydroperoxides (e.g. cumene hydroperoxide, CuOOH), free radical-generating compounds (e.g. menadione), and genotoxic electrophiles (e.g. chlorambucil). By contrast, Nrf2(-/-) MEFs were typically approximately 50% less tolerant of these agents than wild-type fibroblasts, and sulforaphane pre-treatment did not protect the mutant cells against xenobiotics. To test whether Nrf2-mediated up-regulation of glutathione represents the major cytoprotective mechanism stimulated by sulforaphane, 5 micromol/l buthionine sulfoximine (BSO) was used to inhibit glutathione synthesis. In Nrf2(+/+) MEFs pre-treated with sulforaphane, BSO diminished intrinsic resistance and abolished inducible resistance to acrolein, CuOOH and chlorambucil, but not menadione. Thus Nrf2-dependent up-regulation of GSH is the principal mechanism by which sulforaphane pre-treatment induced resistance to acrolein, CuOOH and chlorambucil, but not menadione.
CitationToxicol. Appl. Pharmacol. 2009, 237 (3):267-280
SponsorsWe wish to thank Dr Lesley I. McLellan and Dr Mike McMahon for considerable help and critical advice throughout this study, and also Prof C Roland Wolf for his enthusiastic support. The Association for International Cancer Research (grant no 05-154) and Cancer Research UK (grant no C4909/A7161) are acknowledged for funding this work. Also, a portion of the study was funded by ECNIS (EU network of excellence, contract no. 513943).
- Characterization of the cancer chemopreventive NRF2-dependent gene battery in human keratinocytes: demonstration that the KEAP1-NRF2 pathway, and not the BACH1-NRF2 pathway, controls cytoprotection against electrophiles as well as redox-cycling compounds.
- Authors: MacLeod AK, McMahon M, Plummer SM, Higgins LG, Penning TM, Igarashi K, Hayes JD
- Issue date: 2009 Sep
- Nrf2-regulated glutathione recycling independent of biosynthesis is critical for cell survival during oxidative stress.
- Authors: Harvey CJ, Thimmulappa RK, Singh A, Blake DJ, Ling G, Wakabayashi N, Fujii J, Myers A, Biswal S
- Issue date: 2009 Feb 15
- Induction of cancer chemopreventive enzymes by coffee is mediated by transcription factor Nrf2. Evidence that the coffee-specific diterpenes cafestol and kahweol confer protection against acrolein.
- Authors: Higgins LG, Cavin C, Itoh K, Yamamoto M, Hayes JD
- Issue date: 2008 Feb 1
- Adaptive response to GSH depletion and resistance to L-buthionine-(S,R)-sulfoximine: involvement of Nrf2 activation.
- Authors: Lee HR, Cho JM, Shin DH, Yong CS, Choi HG, Wakabayashi N, Kwak MK
- Issue date: 2008 Nov