Snake Venom for Breast Cancer?
A health report by a Florida television station has created a flurry of attention about a controversial approach to treating breast cancer-snake venom.
WKMG News in Orlando recently did a story on Bill Haast, a 90-year-old researcher who has spent a career studying venoms from some of the world's most poisonous snakes. Haast made a mark in polio research when he discovered that cobra venom affected the same nerve endings as the polio virus. As a result, he helped develop the medicine that is used today to treat the disease.
Recently Haast has turned his attention to copperhead snake venom and its potential impact for treating breast cancer. He refers in the interview to "articles by the hundreds, stories where people were improving miraculously almost." However, he goes on to acknowledge that "red tape" and the Food and Drug Administration have stymied his research.
Interestingly enough, in a presentation at the 1998 annual meeting of the American Chemical Society, Francis Markland, Ph.D. of the University of Southern California School of Medicine reported on his study of a specific protein in copperhead snake venom that may indeed have an impact on tumor growth.
Markland isolated the protein contortrostatin (CN) from purified snake venom and injected it into mice implanted with human breast cancer cells. He found a 60-70 percent reduction in the growth rate of the breast tumors and a 90 percent reduction in tumor metastases (spread) to the lungs.
CN belongs to a class of proteins known as disintegrins, so-named because they disrupt the function of certain other proteins called integrins, which are located on the surface of cells. Integrins are involved in the cell adhesion process.
Markland said that CN appears to inhibit the ability of breast cancer cells to adhere to and invade normal cells in the surrounding tissue. CN also seems to restrict new blood vessel development in tumors, thus starving them of the nutrients they need to grow.
Clearly the use of snake venom to treat breast cancer is controversial, and venom that has not been purified within a controlled laboratory setting can be dangerous.
Currently, the Food and Drug Administration is considering a snake venom trial to treat stroke victims. Ancrod, an experimental drug made from the venom of the Malaysian Pit Viper, may have a benefit for preventing blood from clotting.
And a recent article by University of California, Irvine researchers in the journal Molecular Pharmacology noted that snake venom (and frog skin) may have potential for treating common digestive diseases like irritable bowel syndrome and acid reflux disease.
In the past decades some remarkable medicines have evolved from natural sources. Could snake venom hold the next miracle cure? It will be years before researchers know for sure. In the interim, it clearly remains an extremely risky alternative treatment.
SOURCES:
WKMG, Orlando, Florida (http://www.wkmg.com)
Annual meeting of the American Chemical Society, August 26, 1998, Boston, Mass.
Molecular Pharmacology, April 2001; 59:692-698