Naked role mats are a species which is immune from cancer, and now we know why. The odd-looking rodent produces a unique chemical that protects the animals against the disease.
Vera Gorbunova and Andrei Seluanov are a married pair of biologists who also work together at the University of Rochester. They run a small zoo at the school, featuring a wide variety of rodents, including guinea pigs, mice and naked mole rats.
The species is originally from East Africa, and are more closely related to porcupines than rats. They are odd that they also cannot feel burning from acid or capsasin, it is one of the only two mammals that serves a single breeding queen like a bee, and it is the only mammal that cannot regulate its own body temperature.
Naked mole rats are known to live to be over 30 years old, and so far, no scientist has ever seen cancer develop in a member of that species. On the other hand, 47 percent of typical lab rats develop one kind of tumor or another at some point in their lives, and seldom live beyond the age of four. Even when researchers inject naked mole rats with viruses which usually cause cancer every time in other rodents, naked mole rats are immune from tumors.
In mice and humans, our cells grow and divide until they touch other cells. But the naked mole rat only grows cells to about one-third the density of the cells in our species. The chemical triggering the cells to stop growing, hyaluronan, is what gives naked mole rats their distinctive stretchy skin. The naked mole rat also recycles the chemical very slowly, leading to a buildup of the substance in their bodies. It is believed this is the chemical which prevents the growth of cancer in the species. The two biologists are currently working to see if the adpatation could be imported into another species - mice. The research may go further.
"We think this mechanism could be moved into humans," Dr. Gorbunova said. Hyaluronan is already being used in humans in anti-wrinkle injections and to reduce pain from arthritis in knee joints.
Humans also produce a form of this thick, sugary chemical, but the variety found in human bodies is much shorter than that of the naked mole rat. Hyaluronan latches onto a receptor called CD44 to tell the cell to stop reproducing. In petri dishes growing cells from naked mole rats, the medium turns to a syrupy consistency.
"Our lab technician was unhappy because she needed to disassemble the system and clean all this gooey stuff. I told my graduate student that we have to find out what the gooey substance is - it should be related to their cancer resistance. Of course, at that time it was just a wild guess," Seluanov said.
The hyaluronan adaptation likely evolved to make it easier for the small rodents to make their way underground.
The research behind the discovery was profiled in the journal Nature June 19.
