The team, led by Andrei Seluanov and Vera Gorbunova from the University of Rochester, New York, report their findings in the 19 June online issue of Nature.
The Naked Mole RatA native of East Africa, the naked mole rat (Heterocephalus glaber) is a small, short-sighted, hairless, creature that lives in underground colonies with a social structure like that of bees: each colony has a single breeding queen.
A curious fact about the naked mole rat is that it lives for about 30 years and never gets cancer. This is remarkable for a rodent: take mice, for example, they live for around 4 years and usually die of cancer.
The naked mole rat has many other unusual features: it doesn't regulate its body temperature like other mammals, and it doesn't feel pain when its skin is exposed to acid or the burn of chilli pepper.
These are some of the many things that makes the naked mole rat interesting to study in the lab.
Earlier Study Identified Gene that Makes Naked Mole Rats Cancer-ResistantIn 2009, Seluanov, Gorbunova and colleagues reported their discovery of a gene that stops naked mole rats getting cancer.
They found that the mole rat's cells express a tumor suppressor gene called p16 that stops them proliferating when too many are crowded together. The effect is to cut off runaway growth, the trademark of cancer, before it starts.
The effect of p16 is so strong, that when the team mutated the cells to induce a tumor, their growth barely changed. Yet when they did the same with mouse cells, these became fully cancerous.
Skin Goo of Naked Mole Rat Contains HMW-HAA particular feature that caught the attention of Seluanov and Gorbunova when they worked with skin cells from naked mole rats, was that they oozed a gooey substance. It had an annoying tendency to clog up vacuum pumps and tubing. Also, when growing skin cells in culture, the ones from naked mole rats were viscous, unlike cells from humans, mice, and guinea pigs.
Seluanov says in a statement:
"We needed to understand what the goo was."
They found that the goo is rich in a sugary substance called high molecular weight hyaluronan (HMW-HA).
HA makes tissue supple and helps the healing process. The researchers speculate the mole rats developed high levels of HA to give their skin the elasticity it needs to accommodate life underground.
And given the creature's reputation for being cancer-resistant, they decided to test the role HMW-HA might play in that.
Anti-Cancer Properties of HMW-HAThe team found when they removed HMW-HA from naked mole rat cells, they became susceptible to tumors, suggesting the chemical played a role in making them cancer-resistant.
And, relating back to their previous work when they identified the anti-cancer gene p16 in naked mole rats, the team found that HMW-HA triggers the anti-cancer response of p16.
They also found that a gene called HAS2 is responsible for producing HMW-HA in the naked mole rat. Other animals also have HAS2 but the gene works differently in the mole rat.
The team now wants to test HMW-HA in mice. If that goes well, they hope to try it on human cells.
"There's indirect evidence that HMW-HA would work in people," says Seluanov. "It's used in anti-wrinkle injections and to relieve pain from arthritis in knee joints, without any adverse effects. Our hope is that it can also induce an anti-cancer response."
"A lot of cancer research focuses on animals that are prone to cancer. We think it's possible to learn strategies for preventing tumors by studying animals that are cancer-proof."
Grants from the National Institutes of Health and the Ellison Medical Foundation helped pay for the study.
Some natural mechanisms that ward off cancer can contribute to other diseases. In a study reported recently, US researchers suggest Alzheimer's disease may be the result of a natural anti-cancer mechanism.
Written by Catharine Paddock PhD