Prevention of cancer by agents that suppress production of oxidants
1994
Troll, W. | Lim, J.S. | Frenkel, K.
Structurally different cancer preventive agents suppress superoxide anion radical (O2-.) and hydrogen peroxide (H2O2) production by phorbol ester tumor promoter-activated human neutrophils. This inhibition of H2O2 generation can serve as a facile system for identifying and measuring the activity of cancer preventive agents. Those agents inhibit inflammation and oxidative DNA damage as well as tumor promotion. H2O2 causes formation of strand breaks in DNA and oxidation of DNA bases. Cancer preventive agents include retinoids, garlic oil, protease inhibitors (PIs) isolated from natural sources (e.g., soybeans, potatoes and tomatoes), (-).epigallocatechin gallate (EGCG) (isolated from green tea), vitamin B3 (nicotinic acid), and trans-tamoxifen (TAM). Nicotinic acid and TAM are the new additions to this growing group of inhibitors. Nicotinic acid may act through formation of the cofactor [e.g., nicotine-adenine-dinucleotide (NAD+)] of many dehydrogenases. Phorbol ester-mediated H2O2 induction in neutrophils--which is not inhibitable by estradiol--is suppressed by the antiestrogen TAM, which points to additional properties of TAM that contribute to the prevention of breast cancer but are not estrogenic in nature.
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