TY - JOUR
T1 - 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
AU - Higgins, L G
AU - Kelleher, M O
AU - Eggleston, Ian M
AU - Itoh, K
AU - Yamamoto, M
AU - Hayes, J D
PY - 2009/6/15
Y1 - 2009/6/15
N2 - Sulforphane 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 Nif2(-/-) 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 mu mol/l sulforaphane was very substantially lower in Nrf2(-/-) MEFs than in wild-type cells, and the rebound leading to a similar to 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 mu mol/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. Pretreatment 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 similar to 50% less tolerant of these agents than wildtype 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 mu mol/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.
AB - Sulforphane 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 Nif2(-/-) 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 mu mol/l sulforaphane was very substantially lower in Nrf2(-/-) MEFs than in wild-type cells, and the rebound leading to a similar to 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 mu mol/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. Pretreatment 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 similar to 50% less tolerant of these agents than wildtype 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 mu mol/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.
KW - Glutathione S-transferases
KW - Acrolein
KW - Glutathione
KW - Chlorambucil
KW - Cancer chemoprevention
KW - Menadione
UR - http://www.scopus.com/inward/record.url?scp=67349247003&partnerID=8YFLogxK
UR - http://dx.doi.org/10.1016/j.taap.2009.03.005
U2 - 10.1016/j.taap.2009.03.005
DO - 10.1016/j.taap.2009.03.005
M3 - Article
SN - 0041-008X
VL - 237
SP - 267
EP - 280
JO - Toxicology and Applied Pharmacology
JF - Toxicology and Applied Pharmacology
IS - 3
ER -