Using an imaging technique that records movies of microscopic processes inside living cells, scientists are learning new information about how mutations in certain genes cause cancer and how cancer-fighting drugs work. The procedure also shows promise as a way to rapidly screen compounds for potential use as anticancer drugs, said William Sullivan, professor of molecular, cell and developmental biology at the University of California, Santa Cruz. Sullivan developed the procedure as part of his research on the cell cycle, the process of cell growth and division, and how it is regulated. Mutations in genes that regulate the cell cycle can cause cancer, or unregulated cell proliferation. Drugs used in cancer chemotherapy interfere with the progression of the cell cycle in various ways. Using advanced microscopy and fluorescent labeling techniques, Sullivan is able to observe chromosomes and other key structures within cells as they progress through the phases of the cell cycle. Movies of normal cells show bright blue chromosomes lining up and separating neatly into two daughter cells. When something disrupts the cell cycle, the movies show exactly what part of the cycle has been affected and how.
KEY ANSWERS ON INFLAMMATION
Ten years of research have paid off for Michail Sitkovsky and coworkers at the National Institute of Allergy and Infectious Diseases. They appear to have answered one of the most perplexing questions in immunology: how the body limits inflammation. The finding, reported in the journal Nature, indicates particular cell surface molecules sense runaway inflammation and tissue damage. The tissue swelling, pain and heat are the body's response to a number of situations. These may include invasion by bacteria or viruses, injury or reactions to one's own tissues. Usually, inflammation helps the body fight off invaders. But left unchecked, inflammation can prove dangerous. Chronic inflammation is characteristic of such disorders as asthma, chronic hepatitis, lupus and rheumatoid arthritis. Although many drugs lessen or halt inflammation, very little is known about the body's own mechanism for controlling inflammation and the tissue damage that accompanies it, researchers said. Whatever the signal, its intent is to abate the infection, Sitkovsky said.
ANIMALS AS FACTORIES OF MALARIA VACCINES
Researchers have developed a strain of mice that have a malaria vaccine in their milk. In their study in The Proceedings of the National Academy of Sciences, researchers said that when the purified candidate vaccine was injected into monkeys, it protected four out of five animals from a lethal dose of the malaria parasite. If the process can be enlarged to include such animals as goats, livestock might prove to be inexpensive, high-yield malaria vaccine factories. "A vaccine must not only be effective, it must be cheap to manufacture if it is to be used in those countries hit hardest by malaria," says lead author Anthony Stowers, a malaria researcher at the National Institute of Allergy and Infectious Diseases. "Using transgenic animals to achieve both ends is an exciting possibility. If it works, a herd of several goats could conceivably produce enough vaccine for all of Africa."
NEW CANCER CHEMOTHERAPY TARGET FOUND
Researchers at the University of California, San Diego, School of Medicine and Lund University in Sweden have identified a promising target for cancer chemotherapy. The advance could affect tumor formation and metastasis by stopping cell growth. The findings, reported in The Proceedings of the National Academy of Sciences, show tumors did not grow in the lab dish and in lab mice because the new method interfered with a cell's ability to supply itself with vital subtances called polyamines. Cells depend on polyamines for growth. These substances play a key role in cell proliferation. Cells produce their own and they gather circulating polyamines that come from dietary sources, such as intestinal bacteria, and those excreted by other cells. The scientists also found that a cell-surface sugar molecule called heparan sulfate is critical to the cell's uptake of circulating polyamines. "This paper demonstrates the principle that inhibiting the production of heparan sulfate and blocking the pathway of polyamine formation provides a combination therapy for treating tumors," said study author Jeffrey Esko, member of the Rebecca and John Moores UCSD Cancer Center. "The heparan sulfate inhibitor that we developed worked reasonably well. Now that we've proven the principle, we need to develop better inhibitors."
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