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April 18, 2005 -- The key chemical in a traditional Chinese herbal medicine, danggui longhui wan, may prove useful against cancer, says a study in Proceedings of the National Academy of Sciences of the United States of America.
Danggui longhui wan "has been widely used as a traditional Chinese treatment for chronic myelogenous leukemia," write the researchers, whoincluded Richard Jove, PhD. Jove leads the molecular oncology program at the H. Lee Moffitt Cancer Center & Research Institute in Tampa, Fla.
"It has potent growth inhibitory effects in human tumor cells," they write.
Jove and colleagues condensed the herbal medicine's active ingredients, called indirubins, and made versions to use in their experiment.
The tests were not done on living people or lab animals. Instead, human breast cancer and prostate cancer cells were used.
Tumor-Fighting Effects
Indirubins had already shown potential to fight cancer tumors in past studies, say the researchers. They have been found to display antitumor properties and relatively low toxicity in animal studies.
Now, the researchers think they know a little more about how that happens. Ten different indirubin derivatives were tested.
One particular indirubin derivative dubbed E804 prompted the breast cancer cells to die. Apparently, it blocked a certain gene, known as needed to trigger the start and spread of common cancers in men and woman. By inhibiting the gene, it lowered levels of two proteins needed to prevent cancer cells from self-destructing, say the researchers.
Once these proteins were lowered, cancer cells were able to self-destruct. They say that Stat3 has important implications as a promising target for cancer therapy.
Researchers also call E804 "a potent inhibitor of the Src-Stat3 signaling pathway" that has potential as a tumor-fighting drug.
Cautions for Patients
The study does not recommend the herbal medicine for cancer patients. The indirubin derivatives used in the study aren't commercially available and haven't been tested on people.
People considering using complementary or alternative medicines of any kind -- for any reason --are advised to get safety and effectiveness information and discuss it with their doctor first. That tip comes from the National Center for Complementary and Alternative Medicine, a branch of the National Institutes of Health.
SOURCES: Nam, S. Proceedings of the National Academy of Sciences of the United States of America, April 26, 2005; vol 102: pp 5998-6003. News release, Proceedings of the National Academy of Sciences of the United States of America. National Center for Complementary and Alternative Medicine, "Are You Considering Using Complementary and Alternative Medicine?"