Chinese Compound May Prevent Breast Cancer

A derivative of the sweet wormwood plant, used since ancient times to combat malaria, has been shown to accurately target and kill cancer cells and may soon help in stopping breast cancer before it gains ground.

In a new study, two University of Washington (UW; Seattle, WA, USA) bioengineers discovered that the compound, artemisinin, seemed to prevent the onset of breast cancer in lab rats that had been given a cancer-causing agent. The study was published in the January 8, 2006, issue of the journal Cancer Letters.

"Based on earlier studies, artemisinin is selectively toxic to cancer cells and is effective orally,” said Dr. Henry Lai, research professor in the department of bioengineering, who performed the study with fellow UW bioengineer Dr. Narendra P. Singh, a research associate professor in the department. "With the results of this study, it's an attractive candidate for cancer prevention.”

The characteristics that make artemisinin an effective antimalarial agent also appear responsible for its anti-cancer abilities. When artemisinin comes into contact with iron, a chemical reaction occurs that generates free radicals--highly reactive chemicals that, when formed inside a cell, attack the cell membrane and other structures, killing the cell. The malaria parasite cannot eliminate iron in the blood cells it eats, and stores it. Artemisinin makes that stored iron toxic to the parasite.

The same process appears to be true for cancer. Because they multiply so fast, most cancer cells have a high rate of iron uptake. Their surfaces have large numbers of receptors, which transport iron into the cells. That appears to allow the artemisinin to selectively target and kill the cancer cells, based on their higher iron content. In the latest study, the researchers administered to rats a single oral dose of a substance known to induce multiple breast tumors: 7,12-dimethylbenz[a]anthracene. Half of the rats then were fed regular food, while the other half were fed food with 0.02% artemisinin added. For 40 weeks, researchers evaluated each group for the formation of breast tumors.

Among the rats that did not receive artemisinin, 96% developed tumors. In comparison, 57% of the artemisinin-fed rats developed tumors. Furthermore, the investigators reported, tumors that did develop in the artemisinin-fed rats were both "significantly fewer and smaller in size when compared with controls.”

The cause for artemisinin's apparent preventative effect may be twofold, according to the researchers. The substance may destroy precancerous cells, which also tend to use more iron than ordinary cells, before those cells develop into a tumor. Artemisinin also may suppress angiogenesis, or a tumor's ability to grow networks of blood vessels that allow it to grow. Because artemisinin is widely used in Asia and Africa as an anti-malarial, it is known to be comparatively safe and causes no known side effects, according to Dr. Lai. "The present data indicate that it may be a potent cancer-chemoprevention agent. Additional studies are needed to investigate whether the breast cancer prevention property of artemisinin can be generalized to other types of cancer.”

Chongqing Holley Holdings (Chongqing, China), and Holley Pharmaceuticals (Fullerton, CA, USA), its U.S. subsidiary, supported the research. The company is a world leader in farming, extracting, and manufacturing artemisinin, its derivatives, and artemisinin-based anti-malaria drugs.


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