By Ian Steadman, Wired UK
Blind mole rats don’t get cancer, and geneticists have worked out why: Their cells kill themselves with a poisonous protein when they multiply too much.
[partner id=”wireduk” align=”right”]Mole rats, which live in underground burrows throughout Southern and Eastern Africa, and the Middle East, are fascinating creatures. The naked mole rat, in particular, is the only cold-blooded mammal known to man, doesn’t experience pain, and is also arguably the only mammal (along with the Damaraland mole rat) to demonstrate eusociality — that is, they live in large hierarchical communities with a queen and workers, like ants or bees.
They’re also cancer-proof, which was found in 2011 to be down to a gene that stops cancerous cells from forming. The same team thought that two other cancer-proof mole rat species might have similar genes, but instead it turns out that they do develop cancerous cells. It’s just that those cells are programmed to destroy themselves if they become dangerous.
The two species examined by the University of Rochester’s Vera Gorbunova and her team were the Judean Mountains blind mole rat (Spalax judaei) and the Golan Heights blind mole rat (Spalax golani), which live within small regions of Israel. The team took cells from the rodents and put them in a culture that would force them to multiply beyond what would happen within the animals’ bodies. For the first seven to 20 multiplications, things looked fine, but beyond 20 multiplications the cells started rapidly dying off.
Examining the cells as they died revealed that they had started to produce a protein, IFN-β, that caused them to undergo “massive necrotic cell death within three days”. In effect, once the cells had detected that they had multiplied beyond a certain point, they killed themselves.
It contrasts with the self-preservation method seen in the cells of naked mole rats, which have a hypersensitivity to overcrowding, which stops them from multiplying too much. In the Proceedings of the National Academy of Sciences, Gorbunova hypothesizes that the blind mole rats’ unique habitat — almost entirely underground — might mean that they “could perhaps afford to evolve a long lifespan, which includes developing efficient anti-cancer defences”. Blind mole rats have extremely long lifespans by rodent standards, often living beyond 20 years at a time.
The reasons why this is, though, are still all hypothetical, as the precise mechanism that triggers the production of the IFN-β is still unknown. The hope is that this research could eventually lead to new therapies for cancer in humans.
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