Telomerase fully active in these animals, but they don’t develop the disease, according to Aging Cell study.



Researchers have discovered that small-bodied rodents with long lifespans have evolved an anticancer mechanism that appears to be different from any anticancer mechanisms employed by humans or other large mammals. Investigators noticed that telomerase, an enzyme that can lengthen the lives of cells but can also increase the rate of cancer, is highly active in small rodents but not in large ones.


“Short-lived small species display continuous rapid proliferation of their cells, but these long-lived rodents have somehow found a way to slow down that proliferation when they need to,” says Vera Gorbunova, Ph.D., assistant professor of biology at the University of Rochester.


Before this discovery, scientists assumed that an animal who lived as long as humans needed to suppress telomerase activity to guard against cancer. Since a mouse’s life expectancy is shortened by factors in nature such as predation, it was thought the mouse could afford the slim cancer risk to gain the benefit from telomerase’s ability to speed healing.


However the research team showed that it was body mass not life expectancy that regulated the expression of telomerase. This discovery made researchers question why cancer isn’t rampant in small animals like the common grey squirrel that lives for 24 years or more.


The group found that squirrels, naked mole-rats, chipmunks, muskrats, and chinchillas do express high levels of telomerase. They hypothesize that these species have developed a hypersensitive monitoring function within their cells that senses appropriate and inappropriate cell division. This mechanism would counteract the high telomerase activity and allows them to remain cancer free for the duration of their lifespans.


The study was conducted by researchers at the University of Rochester, the University of San Paulo, and Vanderbilt University.


The findings are published in today’s issue of Aging Cell.








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