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Guggulsterone induces heme oxygenase-1 expression through activation of Nrf2 in human mammary epithelial cells: PTEN as a putative target

Cited 21 time in Web of Science Cited 25 time in Scopus
Authors
Almazari, Inas; Park, Jong-Min; Park, Sin-Aye; Suh, Jin-Young; Na, Hye-Kyung; Cha, Young-Nam; Surh, Young-Joon
Issue Date
2012-02
Citation
Carcinogenesis, Vol.33 No.2, pp.368-376
Abstract
Guggulsterone (GS) [4,17(20)-pregnadiene-3,16-dione] is a phytosterol found in the gum resin of the Commiphora mukul. GS exists naturally in two stereoisomers: E-GS (cis-GS) and Z-GS (trans-GS). In this study, the effects of both isomers on expression of the cytoprotective enzyme heme oxygenase-1 (HO-1) were evaluated in human mammary epithelial (MCF10A) cells. NF-E2-related factor 2 (Nrf2) is considered a master regulator in activating antioxidant response element (ARE)-driven expression of HO-1 and many other antioxidant/cytoprotective proteins. cis-GS upregulated the transcription and protein expression of HO-1 to a greater extent than did trans-GS. cis-GS treatment enhanced nuclear translocation and ARE-binding activity of Nrf2. MCF10A cells transfected with an ARE luciferase construct exhibited significantly elevated Nrf2 transcriptional activity upon cis-GS treatment compared with cells transfected with the control vector. In addition, silencing of the Nrf2 gene abrogated cis-GS-induced expression of HO-1. Incubation of MCF10A cells with cis-GS increased phosphorylation of Akt. The pharmacological inhibition of phosphoinositide 3-kinase (PI3K), an upstream kinase responsible for Akt phosphorylation, abrogated cis-GS-induced Nrf2 nuclear translocation. Pretreatment with the thiol-reducing agents attenuated Akt phosphorylation, Nrf2 activation and HO-1 expression, suggesting that cis-GS may cause thiol modification of an upstream signaling modulator. Phosphatase and Tensin Homologue Deleted on Chromosome 10 (PTEN) is a negative regulator of the PI3K-Akt axis. The mutation in cysteine 124 present in the catalytic domain of PTEN abolished cis-GS-induced HO-1 expression as well as Akt phosphorylation. Whether this cysteine is a 'bona fide' target of cis-GS in its activation of Nrf2 needs additional investigation.
ISSN
0143-3334
URI
https://hdl.handle.net/10371/172710
DOI
https://doi.org/10.1093/carcin/bgr259
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Graduate School of Convergence Science and Technology (융합과학기술대학원)Dept. of Molecular and Biopharmaceutical Sciences (분자의학 및 바이오제약학과)Journal Papers (저널논문_분자의학 및 바이오제약학과)
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