Relevance of anti-inflammatory and antioxidant activities of exemestane and synergism with sulforaphane for disease prevention

Hua Liu, Paul Talalay

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Exemestane (6-methyleneandrosta-1,4-diene-3,17-dione) is a synthetic steroidal inhibitor of the aromatase reaction that catalyzes the terminal and rate-limiting step of the biosynthesis of estrogens. It is active clinically in preventing, delaying progression of, and treating mammary cancers, many of which are estrogen receptor-positive. A striking feature of the structure of exemestane is an extended system of conjugated Michael reaction functions, which is also characteristic of inducers of a broad network of chemoprotective genes regulated by the Keap1 (Kelch-like ECAassociated protein)/Nrf2 (nuclear factor E2-related factor 2)/ARE (antioxidant response element) signaling system. These genes are largely involved in xenobiotic metabolism and antioxidative and anti-inflammatory protection, as well as the synthesis and reduction of glutathione. We show here that exemestane transcriptionally activates NAD(P)H:quinone oxidoreductase 1 (NQO1) and heme oxygenase 1 (HO-1), typical chemoprotective gene products, in a wide variety of mouse, rat, and human cells. It protects several cell lines against oxidative toxicity of tert-butyl hydroperoxide and 4-hydroxynonenal, against free radical damage arising from hypoxia-reoxygenation, and against UVA radiation damage. Exemestane also inhibits the inflammatory increases in inducible nitric oxide synthase (iNOS) in mouse macrophages exposed to LPS (lipopolysaccharide), thereby resembling the isothiocyanate sulforaphane derived from broccoli. Remarkably, combinations of exemestane and sulforaphane act highly synergistically, and this property is also displayed by several other phytochemicals. Thus, exemestane has a wide range of previously unrecognized protective activities, probably unrelated to aromatase inhibition. Its potential for reducing the risk, not only of breast cancer, but also of other chronic diseases that arise from inflammation, oxidative stress, and DNA-damaging electrophiles, requires exploration, particularly in view of the synergism with other phytochemicals.

Original languageEnglish (US)
Pages (from-to)19065-19070
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number47
StatePublished - Nov 19 2013

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Relevance of anti-inflammatory and antioxidant activities of exemestane and synergism with sulforaphane for disease prevention'. Together they form a unique fingerprint.

Cite this