Being a naked mole-rat sure has its ups and downs. Resembling a saber-toothed sausage would have to go down as one of the negatives, but on the plus side you get to outlive all other rodents, lack sensitivity to pain, and never have to worry about cancer. Researchers have spent years trying to figure out what makes these unsightly subterranean creatures so cancer-resistant, and a new study in the journal Nature may have just revealed a vital piece of the puzzle.
Aside from being the only cold-blooded mammal, naked mole-rats are remarkable for their longevity. While a typical mouse of a similar size would be lucky to live past the age of four, these wrinkly tunnellers can survive for an incredible 30 years.
Their avoidance of the Grim Reaper is helped by their apparent immunity to cancer, and scientists are now locked in a debate over the mechanisms behind this magnificent advantage. A study that came out in 2013 found that naked mole-rat cells secrete a substance called hyaluronan (HA) that is five times longer than that produced by humans. Because HA acts as a kind of scaffold that supports cells and moderates their proliferation, the researchers concluded that this unusually robust HA makes the animals’ cells completely invulnerable to cancer.
To test this, the authors of the new study created numerous cell lines from tissue extracted from naked mole-rats and exposed them to genes that are known to cause cancer in other rodents. In the petri dish, these naked mole-rat cells became cancerous and then developed into tumors when transplanted into living mice.
The authors therefore conclude that naked mole-rat cells are not inherently immune to cancer, but that the rodent’s freedom from the disease must be due to “a non-cell autonomous mechanism,” possibly involving an effective immune system response to cancer.
Commenting on this finding, study author Dr Walid Khaled said in a statement that “if we can understand what’s special about these animals’ immune systems and how they protect them from cancer, we may be able to develop interventions to prevent the disease in people.”
While this sounds like progress, the authors of the 2013 study are unconvinced by these new findings and published a response stating that these results only prove that naked mole-rat cells can become cancerous when exposed to “artificially high” levels of cancer genes. They maintain, however, that naked mole-rat cells remain inherently resistant to cancer when these genes are expressed at a natural rate.
Clearly, certain big questions have not yet been answered to everyone’s satisfaction, but if further research into the naked mole-rat’s lack of vulnerability to cancer can produce a scientific consensus, then we may be on our way to understanding how to better treat the illness in humans.
4
