Biologists at the University of Rochester have found that small-bodied rodents with long lifespans have evolved a previously unknown anti-cancer mechanism that appears to be different from any anticancer mechanisms employed by humans or other large mammals. The findings are published in today's issue of Aging Cell.
Understanding this mechanism may help prevent cancer in humans because many human cancers originate from stem cells and similar mechanisms may regulate stem cell division.
"We haven't come across this anticancer mechanism before because it doesn't exist in the two species most often used for cancer research: mice and humans," says Vera Gorbunova, assistant professor of biology at the University of Rochester, a principal investigator of this study. "Mice are short-lived and humans are large-bodied. But this mechanism appears to exist only in small, long-lived animals."
Gorbunova believes that cells of long-lived, small-bodied rodents are hypersensitive to cues from the surrounding tissue. If the cells sense that conditions are inappropriate for growth, they slow down cell division. Such a mechanism would arrest tumor growth and prevent metastases.
Gorbunova's team has worked at length investigating the links between body size and lifespan in rodents because rodents range in size from tiny field mice to the human-sized capybara of Brazil. She can use them to compare size and lifespan across several different-sized but closely related animals. She discovered that telomerasean enzyme that can lengthen the lives of cells, but can also increase the rate of canceris highly active in small rodents, but not in large ones.
Until Gorbunova's research, the prevailing wisdom has assumed that an animal that lived as long as we humans do needed to suppress telomerase activity to guard against cancer. Telomerase helps cells reproduce, and cancer is essentially runaway cellular reproduction, so an animal living for 70 years has
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University of Rochester