Researchers at the Johns Hopkins School of Medicine have discovered that a natural product isolated from a traditional Chinese medicinal plant commonly known as thunder god vine, or lei gong teng, and used for hundreds of years to treat many conditions including rheumatoid arthritis works by blocking gene control machinery in the cell. The report, published as a cover story of the March issue of Nature Chemical Biology, suggests that the natural product could be a starting point for developing new anticancer drugs.
"Extracts of this medicinal plant have been used to treat a whole host of conditions and have been highly lauded for anti-inflammatory, immunosuppressive, contraceptive and antitumor activities," says Jun O. Liu, Ph.D., a professor of pharmacology and molecular sciences at Johns Hopkins. "We've known about the active compound, triptolide, and that it stops cell growth, since 1972, but only now have we figured out what it does."
Triptolide, the active ingredient purified from the plant Tripterygium wilfordii Hook F, has been shown in animal models to be effective against cancer, arthritis and skin graft rejection. In fact, says Liu, triptolide has been shown to block the growth of all 60 U.S. National Cancer Institute cell lines at very low doses, and even causes some of those cell lines to die. Other experiments have suggested that triptolide interferes with proteins known to activate genes, which gives Liu and colleagues an entry point into their research.
The team systematically tested triptolide's effect on different proteins involved with gene control by looking at how much new DNA, RNA and protein is made in cells. They treated HeLa cells with triptolide for one hour, compared treated to untreated cells and found that triptolide took much longer to have an effect on the levels of newly made proteins and DNA, yet almost immediately blocked manufacture of new RNA. The researchers then looked more closely at the
|Contact: Audrey Huang|
Johns Hopkins Medical Institutions