June 20, 2013
Biological Causes Of Naked Mole Rat Cancer Resistance Discovered
redOrbit Staff & Wire Reports - Your Universe Online
A team of investigators led by Andrei Seluanov and Vera Gorbunova of the University of Rochester report in this week's edition of the journal Nature that they have located a substance that makes the burrowing rodents essentially cancer-proof.
The substance, according to Elizabeth Pennisi of Science Now, is a complex sugar known as hyaluronan (HMW-HA) that keeps the naked mole rats' cells from clumping together and forming tumors. The researchers conducted laboratory tests on the skin cells of the small, hairless, subterranean rodents and discovered high levels of HMW-HA, BBC News added.
While attempting to grow naked mole rat cells in a lab dish, Seluanov and Gorbunova discovered that the cells would not move too close together, and over time the contents of the dish would become remarkably gooey. In fact, Pennisi said, it became so difficult for the scientists to work with the cells that they ultimately had to remove the goo-causing substance, hyaluronan. Doing so caused the cells to clump together, hinting that without HMW-HA, the cells might be capable of forming into tumors.
“The scientists wondered if this long hyaluronan helped naked mole rats fight cancer," explained Carl Zimmer of the New York Times. “They added hyaluronan-destroying enzymes to populations of naked mole rat cells to see what would happen. Instead of arresting their growth at a low density, the cells now grew into thick clusters, just as cancer-prone mouse cells do."
“The scientists next shut down the gene in naked mole rat cells that encodes hyaluronan. They then inserted a cancer-causing virus. Instead of resisting the virus, the hyaluronan-free cells multiplied wildly," Zimmer added. “And when the researchers moved the naked mole rat cancer cells into mice, the cells grew into full-blown tumors. Suddenly, naked mole rat cells became as vulnerable to cancer as mouse cells — or human cells."
The fact that the cells became susceptible to tumors once HWM-HA was removed demonstrates that the chemical does in fact play a role in making the East African rodents cancer-proof, the researchers explained. In addition, Seluanov and Gorbunova identified the gene responsible for making hyaluronan in the naked mole rat. That gene, which is known as HAS2, was found to be different than the same gene in other animals.
Furthermore, the naked mole rats were found to be extremely slow at recycling HMW-HA, which contributed to the accumulation of the substance in the animals' tissues. Next, the researchers will attempt to test the effectiveness of the chemical in mice, and if that proves successful, the husband-and-wife team of Seluanov and Gorbunova ultimately hope to see what impact HWM-HA would have on human cells.
“There's indirect evidence that HMW-HA would work in people," Seluanov explained Wednesday in a statement. “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," added Gorbunova.