p53 by Sue Armstrong

Author:Sue Armstrong [Armstrong, Sue]
Language: eng
Format: epub
ISBN: 9781472910530
Publisher: Bloomsbury Publishing

A FINE BALANCE BETWEEN LIFE AND DEATH

Evan had met even stronger resistance to his ideas some years earlier when his research into oncogenes suggested to him that all our cells contain both growth and suicide programmes that are in constant, hair-trigger competition. Which course of action a cell takes is essentially controlled by its environment and the signals it receives from its neighbours: is it in the right place and at the right time? Is it behaving normally? If so, it will receive ‘stay alive’ signals; if not, it will be instructed to abort. This is an inbuilt defence mechanism and one of the reasons cancer is so rare, believes Evan.

Since this story takes us back among the Petri dishes in the lab, it may seem like a diversion from the topic in hand, animal models. But besides describing another pivotal moment in cancer research, it helps show why it is so important that experiments are performed in living organisms as well as in cell and tissue cultures. It begins in the late 1980s, when Evan, newly recruited to the ICRF in London, was doing some experiments with the powerful oncogene Myc, looking at how it drives cell proliferation. ‘I made this bizarre observation that when you expressed Myc at high levels in cells they did indeed proliferate – but when you looked a couple of days later, there were fewer cells than before,’ he explains. ‘I’m a great believer in personal observation – observing things, you ask questions of what you can actually see. So we took these cells and we put them under a microscope and we used time-lapse video to take one frame every three minutes. Then you speed it up and watch what happens over three or four days in just two or three minutes. And there we saw this amazing phenomenon . . . the cells were replicating, but also they were dying by apoptosis.’

This was exciting, but it didn’t make sense. Then a thought struck Evan that drew on his early training in immunology, where a common theory was that the immune system plays a part in protecting us from cancer by eliminating rogue cells that it recognises as foreign. ‘I thought what if, instead of the immune system acting as a police service to find aberrantly proliferating cells, there is, hard-wired into the very warp and weft of how cells proliferate, an abort programme? Every time you pick up the machinery to proliferate, you also pick up the machinery to kill yourself?’

If that were the case, he reasoned, there must be something that tells the cells whether to live or die, and here he found a clue in the growth medium he was using for his experiments. Most of the time, he used serum – the colourless liquid the body produces at the site of a wound that makes it ‘weep’ – because serum contains substances that promote clotting of blood, and survival, growth and proliferation of cells to help in the recovery and regeneration of injured tissue.

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