Short chromosomes put cancer cells in forced rest

A Johns Hopkins team has stopped in its tracks a form of blood cancer in mice by engineering and inactivating an enzyme, telomerase, thereby shortening the ends of chromosomes, called telomeres. "Normally, when telomeres get critically short, the cell commits suicide as a means of protecting the body," says Carol Greider, Ph.D., the Daniel Nathans chair of molecular biology and genetics at Johns Hopkins. Her study, appearing online this month at Cancer Cell, uncovers an alternate response where cells simply - and permanently - stop growing, a process known as senescence. In an unusual set of experiments, the research team first mated mice with nonoperating telomerase to mice carrying a mutation that predisposed them to Burkitt’s lymphoma, a rare but aggressive cancer of white blood cells. Telomerase helps maintain the caps or ends of chromosomes called telomeres, which shrink each time a cell divides and eventually - when the chromosomes get too short - force the cell to essentially commit suicide. Such cell death is natural, and when it fails to happen, the result may... Whole article: "http://www.physorg.com":[ http://www.physorg.com/news96725693.html]

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