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Chemoprotection against cancer by phase 2 enzyme induction
P Talalay1, J W Fahey, W D Holtzclaw
1Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Toxicology Letters
|December 1, 1995
Summary
Mammalian cells possess protective mechanisms against carcinogens, involving Phase 2 enzymes and glutathione. Broccoli contains sulforaphane, a potent inducer of these enzymes, which blocks tumor formation.
Area of Science:
- Biochemistry
- Toxicology
- Molecular Biology
Background:
- Mammalian cells have defense systems against toxic and carcinogenic compounds.
- Phase 2 enzymes and glutathione are key in cellular protection.
- These enzymes are induced by various chemicals, blocking chemical carcinogenesis.
Purpose of the Study:
- To investigate the role of Phase 2 enzymes in cellular protection.
- To identify natural inducers of Phase 2 enzymes.
- To evaluate the anti-carcinogenic potential of plant-derived compounds.
Main Methods:
- Studied the transcriptional induction of Phase 2 enzymes via the antioxidant/electrophile response element (ARE/EpRE).
- Screened various chemical classes for their ability to induce Phase 2 enzymes.
- Isolated and identified sulforaphane from broccoli as a potent inducer.
Main Results:
- Phase 2 enzyme induction is a critical protective mechanism.
- A wide array of chemical agents, including those found in plants, can induce Phase 2 enzymes.
- Sulforaphane, isolated from broccoli, is a highly effective Phase 2 enzyme inducer and demonstrated efficacy in blocking mammary tumor formation in rats.
Conclusions:
- Phase 2 enzyme induction is a significant cellular defense against chemical carcinogens.
- Dietary components, such as sulforaphane from broccoli, can modulate these protective pathways.
- Sulforaphane shows promise as a chemopreventive agent against chemically induced cancers.