The naked mole rat is of particular interest to longevity researchers. The animals live 10 times as long as their cousin rodents, more than 30 years. They are resistant to disease and in particular never get cancer.
Researchers have been trying to uncover the mechanisms by which the animals don’t get cancer. In a new study published in the journal Nature scientists report a striking new finding.
In previous research the group found that naked mole rat cells were inhibited from growing when they came in contact with other cells in culture at a much lower density than cells from other animals. The mechanism of this contact-inhibition cancer resistance was unknown. The researchers observed however that the naked mole rat cultures became very viscous over time.
They discovered the reason for this viscosity was that the naked mole rat cells made a unique version of a particular protein called hyaluronan. This is a molecule found in the spaces around cells that keeps tissue firm and flexible. The naked mole rat has a highly unusual high molecular weight variant of the molecule, quite different than what is found in humans, and became named HMM-HA.
The researcher discovered if they removed this hyaluronan from cell cultures, the naked mole rat cells could turn cancerous, proving this specialized hyaluronan was the reason these animals did not get cancer.
Interestingly these animals normally live in tightly packed underground tunnels so their tissue needs to be very springy such that they can squeeze through the tunnels without getting stuck. It is possible natural selection favored the development of this specialized hyaluronan which coincidentally also prevents cancer.
They also showed the cancer preventing effects of the hyaluronan was mediated by the CD44 receptor on the cells to which it binds.
The authors conclude:
Using naked mole-rat HMM-HA in the clinic or targeting the HA–CD44 signalling pathway, opens new avenues for cancer prevention and life extension.