Register for Not all herbal mixtures have same effects
Prostate CancerMarch 24, 2003
Billions of dollars have been spent by U.S. consumers on alternative herbal therapies for the treatment of prostate cancer, which killed more than 30,000 American men last year, according to the U.S. Centers for Disease Control and Prevention.
Now, a new study on the cancer-fighting properties of these supplements by investigators at the University of Virginia (U.Va.) Health System shows that not all work the same biologically, even though they contain the same ingredients. Their research is published in Oncogene.
The research team, led by Dr. Dan Theodorescu, professor of molecular physiology and urology at U.Va., compared the herbal extract PC-SPES with a similar product called PC-CARE and found the two mixtures have different biological actions. PC-SPES is an abbreviation for "prostate cancer hope" ('spes' is hope in Latin) and is made up of a special blend of eight Chinese herbs. In some clinical trials, the mixture lowered a patient's level of prostate specific antigen (PSA) by up to 50% and had better results than a synthetic estrogen, diethylstilbestrol (DES), which is also used in prostate cancer patients.
PC-SPES was taken off the market a year ago, according to the Food and Drug Administration, after investigators found it some lots were contaminated with prescription drugs, including DES, a blood thinner and an anti-inflammatory drug.
Some cancer patients are rationing their PC-SPES pills as a result, according to news reports. The manufacturer has also gone out of business, causing other companies to make and market several other herbal mixtures with the same ingredients.
Using gene expression profiling, Theodorescu and his team found that the action of PC-CARE on prostate cancer cells was almost identical to DES, which blocks the male hormones that cause prostate cancer. The U.Va. researchers found, on the other hand, that PC-SPES affects completely different genes than DES, suggesting that estrogen is not the primary ingredient that acts on prostate cancer.
"This approach can be used to compare mixtures blended by different manufacturers using similar ingredients to see if they affect similar genes and are likely to have the same effect in patients with prostate cancer," Theodorescu said. "The results also highlight the fact that not all botanical formulations, even if they have the same basic ingredients, necessarily act the same on prostate cancer. This has been known for some time by patients and physicians but had not been evaluated using molecular tools."
Researchers identified several genes involved in the cell cycle of prostate cancer that are affected by PC-SPES. One gene, called NIMA-related kinase 2, is induced by PC-SPES and may be associated with arresting growth in cancer cells. By understanding the gene expression fingerprint induced by herbal mixtures, researchers at U.Va. are developing tools to identify which ingredients have the most beneficial effect on prostate cancer. "We may also eventually use this information to develop new drugs. That's what we're hoping for," Theodorescu said. This article was prepared by Cancer Weekly editors from staff and other reports.
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