timeworn A drug once used to fight against a kind of worm infection may find himself called into service against a new enemy - cancer liver. According to a report in the Feb. 17 issue of Journal of the National Cancer Institute oltipraz the drug can help detoxify aflatoxin, a carcinogen common in the tropics.
Liver cancer is relatively rare in North America and Europe, is the most common type of cancer in parts of Africa and East Asia, which represents up to 15 % of all deaths. A major risk factor is aflatoxin ingestion years, an aromatic compound produced by the fungus Aspergillus , which often contaminate the soybeans, peanuts and corn. Many human enzymes metabolize aflatoxin; some convert epoxy aflatoxin, a potent DNA damaging agent; others attach a chemical tag to aflatoxin to banish to the kidneys where it is excreted as mercapturic acid. In theory, aflatoxin damage can be checked by blocking enzymes "bad" and strengthen "good".
theredecades developed to treat parasitic infection schistosomiasis, oltipraz has since been replaced by more effective drugs. But the drug is known to increase levels of a small peptide, glutathione, inside cells. Because glutathione is involved in the elimination of toxic substances, scientists have questioned whether oltipraz may protect against cancer by helping the excretion of aflatoxin. In a previous study, toxicologists John Groopman and Thomas Kensler of Johns Hopkins School of Public Health in Baltimore found that giving rats oltipraz protected them from liver cancer induced by aflatoxin limiting enzymes "bad", mainly P450 cytochrome, and strengthening eliminators.
in the new study, the team administered oltipraz to 233 men and women in Qidong, China, who had detectable levels of aflatoxin in their blood. Low doses led to an increase of 2.6 times in the mercapturic acid, while higher doses led to a double reduction of a by-product of carcinogenic metabolite. Kensler says the results show that oltipraz can both inhibit the conversion of aflatoxin in carcinogenic detoxification and promote its -. And may protect people against cancer
"This is a truly novel approach to interfere with a natural carcinogen," said John Hayes, a cancer expert at the Center for Biomedical Research of the University of Dundee in Scotland. But he warned that "people are skeptical" when it comes to cancer prevention with chemicals, because of doubts about their effectiveness and the risk of long term side effects. As a short-term treatment is sufficient to cure schistosomiasis, nobody knows what the risks of prolonged use are oltipraz. Kensler said his group will begin a 12-month trial in March to explore.
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