To: George Leeper who wrote (2273 ) 2/21/2000 7:52:00 PM From: Asymmetric Respond to of 3576
Researchers Find Telomerase Enzyme Can Shield Mice Against a Cirrhosis The Wall Street Journal Interactive Edition -- February 18, 2000 By LAURA JOHANNES / THE WALL STREET JOURNAL BOSTON -- Researchers at Dana-Farber Cancer Institute found that an enzyme that repairs tiny cellular clocks called telomeres can protect mice against liver cirrhosis. The paper, published in Friday's issue of the journal Science, is the most dramatic demonstration to date that boosting cellular levels of the enzyme, called telomerase, may be useful in treating disease. Previously, interest in telomerase and telomeres has focused on the notion that they could somehow be used to lengthen life spans generally. Although that hope has so far proven elusive,the cirrhosis news is likely to heighten the interest of biotechnology companies in finding telomerase-boosting drugs for a wide variety of conditions. Already, a handful of companies, including Geron Corp., Menlo Park, Calif., have active telomerase research programs. "Cirrhosis is one of several disorders, including multiple sclerosis and AIDS, where cells lose their ability to regenerate," says Jerry Shay, a professor of cell biology at the Univ of Texas Southwestern Medical Center. "Telomerase may be able to restore that ability." Telomeres, or "end parts" in Greek, are protective caps on the ends of chromosomes, the gene-bearing cellular structures. Some of the most intriguing and mysterious parts of the cell, telomeres appear to get shorter with each generation of cell division. What they do has been a source of controversy, but some scientists believe they serve as little fuses that tell cells when to stop reproducing themselves. Cirrhosis is a fatal condition often related to hepatitis or alcoholism in which the liver, the organ that removes toxins from the blood, stops working properly. After continued destruction, "liver cells run out of telomeres and lose their ability to regenerate," says Dr. Ron DePinho, a researcher at Dana-Farber. The Dana-Farber researchers, working with colleagues at the Albert Einstein College of Medicine, the Bronx, N.Y., created a strain of mice with exceptionally short telomeres. Then they attempted to cause cirrhosis in the mice with various methods, including giving them a poison that affects the liver and removing two-thirds of their livers surgically. The scientists found that the short-telomered mice were dramatically more likely to develop cirrhosis than normal mice, which are notoriously resistant to the disease. Moreover, when the researchers used gene therapy to insert telomerase into the cells of the special strain of short-telomered mice, these mice also proved remarkably resistant to cirrhosis. Before telomerase can be tested in humans for cirrhosis, scientists must figure out how to deliver it into cells and then establish its safety. Some scientists fear that telomerase therapy, by allowing cells to divide indefinitely, could spur cancer. But Dr. Shay argues that so many things contribute to tumor formation that "there is no reason to say that telomerase alone is going to cause cancer." It will take at least five to 10 years until telomerase therapy can be tested in humans for cirrhosis, but "we're extremely motivated to move this into the clinic," says Dr. DePinho, who plans more mouse experiments to confirm the discovery. Write to Laura Johannes at laura.johannes@wsj.com