• Question: I would like to ask all the scientists, however, this question is for Mariana and Susanne in particular, as it especially coincides with their fields of work. Mole rats have developed a somewhat immunity to cancer, and different species of mole rat have themselves done this in unique ways. The Blind Mole Rat, for example, controls its cellular division; any division above a certain rate triggers immediate apoptosis of the uncontrollably dividing cells and other cells in the immediate vicinity. Susanna, could a similar response in humans potentially solve the problem of tumours ‘walking’ around in the brain? More relevant to Mariana, though, is the Naked Mole Rat, which has developed an immunity to cancer because its cells are sensitive to overcrowding. Once they have divided to a certain extent they will no longer divide as they are under too much pressure. The cells know what size is ‘too big’. Is this a similar concept to that of the growth of our own organs and could this potentially become a cancer preventing trait in humans? For many years scientists have sort a way to regrow tissues and limbs in humans, as is seen in many other animals. Most relevant is the Spiny Mouse, which is another mammal capable of this regrowth, showing that humans may potentially have this ability dormant within their genes. If we analysed how mole rats control and prevent cancerous cells and were to use this in tandem with research on the regenerative properties shown by the Spiny Mouse, would it be plausible to think we could harness cancer as a way of regenerating damaged tissues and lost limbs, and at a rapid rate?

    Asked by murtagh to Clare, Mariana, Pedro, Robert, Susanne on 9 Nov 2012.
    • Photo: Robert Insall

      Robert Insall answered on 9 Nov 2012:

      Nope.

      Actually the way you put it is very clear (you’ve plainly been reading), but illustrates the problem. Bad stuff happens. You can guard against it at a cost, but you have to pick how much you’re willing to pay. Your body could repair its genes far more carefully, at a large cost in energy, then you’d get cancer less often – but it would cost so much energy you’d have fewer babies, go slower, and generally work less well. Our bodies are actually very well tuned to balance these things.

      Our bodies could also keep lots more stem cells around, ready to regenerate body parts if we had an accident. The stem cells are the key to regeneration because they can make new structures rather than maintain old ones. But stem cells are central to cancer too – if you have more stem cells, you regenerate better, but you get more cancers. Again, we’re fairly well tuned, though it would be nice to turn it on and off a bit more easily if we wanted to.

    • Photo: Susanne Muekusch

      Susanne Muekusch answered on 10 Nov 2012:

      Hello murtagh,

      oh wow, what a complicated multiparte question- I am impressed! I needed to read it twice.
      To stop the cells from migrating through the brain and to stop them from dividing are really two very different things. There is even evidence that brain cancer cells either divide or migrate. If you can keep the cancer cells from dividing, the ones that are migrating will continue to do so. Of course, if you find a way to stop the cells from dividing that would cure every kind of cancer. But we are no mole rats, so our cells do not have the same internal control systems. But being human certainly comes with its own benefits 😉

      More of an overall comment on the “different species and cancer theme”: It is well known that some species are more suscebtible to cancer than others. Most of the time it is not known why. For example plants virtually never get endogenous cancers (that is, cancers which are not caused by other organisms such as bacteria). Plants can get really old plus they continue growing for a lifetime and are masters of regeneration. Some reptiles, like lizards, can regenerate whole limbs, but are relatively cancer resistant.

      Even if we do understand what is happening in other species (and I don’t think that mole rat story is even close to complete)- we are still human! I don’t see that we can combine regenerative properties from one species and growth control from another species, or even use one of them on human cells. These processes are very complicated and rely on inherent properties of the cells, which human cells just do not have. For example, it has long been known (for at least 30 years) that fish can regrow nerve cell endings through spinal transections. Still, we cannot use this knowledge to help paraplegic patients after spinal chord injury.

    • Photo: Clare Taylor

      Clare Taylor answered on 13 Nov 2012:

      Twice?? I had to read your question three times! I think both Robert and Susanne have made some really interesting points. There’s been some interesting work done on mole rats recently – researchers have been trying to grow cells from the blind mole rat in the lab and observed mass cell suicide – the apoptosis that you mention. But of course, in order to study the cells to try to understand what is happening, researchers need to keep the cells alive in the lab, which they currently can’t do. It’ll be interesting to see if they can figure it out!

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