• Question: Would it be possible to use the gene that naked mole rats have that make them immune to cancer to help find a cure for cancer in humans?

    Asked by ted14 to Chris, Dave, David, Fiona, Jack on 24 Jun 2013.
    • Photo: David Freeborn

      David Freeborn answered on 24 Jun 2013:


      Hi ted14,

      Yes: it’s very likely this could help, but not certain!

      When scientists tried to grow naked moler rat cells in the lab, they found the equipment kept clogging up with a “mysterious goo”. This turns out to be a chemical called hyaluronan, or HMW-HA, a sugary substance that fills the gaps between cells in all mammals. But naked mole rats produce 5 times as much as other mammals, due to a particular gene, HAS2.

      The HMW-HA activates another gene, which kills off overcrowding cells. This is precisely what cancer cells do, so the naked mole rat gene will kill off any cancers before they can even form tumours.

      It might be possible that supplanting the gene in humans would make us very cancer-resistant. But there’s probably an easier alternative! We already inject people with HMW-HA to prevent wrinkles or relieve pain from arthritis. So we might be able to inject humans with huge quantities of this stuff to prevent cancer as well. It’s very likely that it could have a similar effect in humans, but not yet certain.

      In the future, perhaps we will genetically modify humans to have this gene too- if it works.

      ***

      There’s some interesting evolutionary science about why naked mole rats might have this gene.

      Most animals in the wild die from being eaten or from accidents. For example, in elephants the age is up to about 60 years, very long, while in mice it is under a year. For early homo sapiens it was probably about 30 years.

      Most animals begin ageing at about double this average age of predation, because it is no longer evolutionarily efficient for the body to fight back against the ageing process- because most animals will probably be dead by this point anyway. So humans begin to age significantly by about the age of 60, and if you had a pet mouse, it would start to show significant signs of ageing after just a couple of years.

      Naked mole rats live in huge underground colonies, and so they have very few natural predators. As a result, they have avery long life expectancy, for a rodent, of about 30 years. That’s about 10 times longer than other rodents of a similar size. They’ve had to evolve a lot of mechanisms to fight back the effects of long-life, and this anti-cancer gene might be part of that.

    • Photo: Dave Farmer

      Dave Farmer answered on 24 Jun 2013:


      Hello ted,

      Having looked into it a little bit, it appears that there are a few possible reasons that the naked mole rats are apparently resistant to cancer, so it might not be as simple as a single gene.

      In answer to your question, yes I believe it’s possible that it will help, although it is improbable that this will result in a complete cure for cancer in humans. Certainly understanding how they are immune might give us new ideas for cancer prevention in humans, but it is unlikely that we’ll be able to directly carry across the mole rat’s method into humans. We are very different physiologically after all (good job too, they’re ugly little so and so’s!).

      One thing to be aware of in general is the trend in the media to jump on a scientific discovery and to speculate far beyond what is sensible as to the possible applications of said discovery. Scientists often don’t help themselves with this, as it’s part of our job to try make our research sound exciting and worthwhile! ‘Cures’ for cancer seem particularly prone to this sort of overselling. It’s always best to bear in mind this:

      http://xkcd.com/1217/

      Dave

    • Photo: Jack Miller

      Jack Miller answered on 24 Jun 2013:


      Hi Ted14,

      Cancer’s a really hard problem. It’s best to look at it from an evolutionary perspective: at some point in the distant past, cells went from competing against each other individually (and reproducing individually) to living in colonies, where reproduction had to be closely monitored. It’s quite a sacrifice, and quite an interesting one to think about — the common advantages outweigh the cost to each cell. Cellular reproduction in organisms such as us is highly regulated, and if anything goes wrong cells that behave abnormally get dispatched, usually by the immune system (there’s a type of immune cell called ‘natural killer’ cells to do just this — great name!).

      Cancer is a disorder of cellular reproduction. Unfortunately, cellular reproduction’s really bloody complicated, and cancer predominantly affects those people who are older (and whose cells have divided a lot more). This complicates the matter even further, as it’s really hard to understand what drives the transition from normal cells to cancer cells in people. There’s also another really important point here: the reason we get cancer later in life is because we haven’t been subject to evolutionary pressures in later life. We just simply haven’t been alive into our seventies until very recently, and, moreover, we don’t have children when we’re in our seventies (most of the time, at least…), and so there’s no biological incentive _not_ to get cancer.

      This is highlighted in rats of the more normal variety. If you had a pet rat, you’d find it hard to keep him or her alive for more than about three years. The simple reason is that, over evolutionary time, rats just don’t live that long — they go ‘crunch’ as lunch for something else well before that point — and so they get all sorts of diseases that tend to affect humans in later life (cancer and heart disease are two big ones).

      As David says, naked mole rats do probably live a long time in underground colonies. So, it’s not surprising they’ve worked out ways of dealing with these problems (our bodies have too). I’m sure that people are actively researching what’s going on, and will be trying to use anything they can to create another useful tool in the fight against cancer.

      — Jack

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