In all the years that biologists have studied the naked mole rat, they’ve yet to detect a single incidence of cancer. That’s amazing. And pretty damned important to understand. A recent experiment has offered an important clue as to how this extraordinary rodent pulls off this feat — and it has to do with its penchant for nudity.
Just looking at these things you know naked mole rats aren’t like other mammals.
As their appearance and behavior suggests, these hairless creatures can’t figure out if they’re rodents, insects, or lizards. They spend their entire lives underground engaging in a kind of insectoid existence; it’s a species that’s adapted to colonial life. The queen is the only female that breeds, and her offspring spend their days either protecting the colony or digging burrows with their powerful incisors. And because they can't maintain a steady body temperature, they may as well be considered a cold-blooded mammal.
But not only that, they’re exceptionally long lived. Like ridiculously long lived — especially for an animal with such a small body mass. Unlike mice, which live about three to four years, naked mole rats can live an astounding 30 years!
The reason for the naked mole rat’s remarkable longevity may have something to do with its unusual resistance to cancer — and it might be on account of its unique subterranean lifestyle.
Or at least, one particular adaptation it’s had to make to live a life underground.
Specifically, naked mole rats have skin cells that are high in a natural sugary substance that stops tumors from developing. It’s called hyaluronan (HMW-HA), and it produces a version of this sugar that’s over five times bigger than ours — and at significant quantities.
Hyaluronan works as a kind of thickening agent, and it’s common in the skin, cartilage, and other connective tissues. Its anti-cancer qualities may have something to do with the way it prevents cells from breaking free and growing into tumors. It may also prevent cells from dividing when they become too crowded (a process called contact inhibition).
Experiments conducted by researchers from the University of Rochester, New York, showed that when hyaluronan is removed from naked mole rat cells, they become susceptible to tumors.
The researchers speculate that the naked mole rats evolved higher concentrations of HA in the skin to provide the skin elasticity needed for life in underground tunnels. It’s just a coincidence that it also happens to be a powerful anti-cancer agent.
The next step is to test the chemical in mice, and then humans. Lead scientist Andrei Seluanov says there’s direct evidence that HMW-HA would work in people, too.
Interestingly, a similar version of the chemical is used as a medicine to treat arthritis and in anti-wrinkle jabs.
Read the entire study at Nature: “High-molecular-mass hyaluronan mediates the cancer resistance of the naked mole rat.”
Top image: San Diego Zoo.