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Asked by amberhoward to Anouk, Chris, Judith, Leisha, Seyyed on 11 Jun 2012.
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Judith Sleeman answered on 11 Jun 2012:
Yes, cells absolutely can kill themselves. They use a process called ‘apoptosis’ to die quickly and quietly without leaving any toxins behind them to damage any other cells. It’s really important that cells die at the right time and place when an embryo is developing, otherwise we’d end up (for example) with big flat spade-hands instead of fingers. It’s also an important way for the body to defend against cancer: if cells don’t die when they are supposed to and keep multiplying to make new cells it can lead to a tumour.
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Anouk Gouvras answered on 11 Jun 2012:
I didn’t know that answer to this question (good question) as I had forgotten about ‘apoptosis’. Thanks very much Judith! Aren’t cells amazing!
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Chris Kettle answered on 12 Jun 2012:
Yes and imagine if cells didn’t….. did you see the episodes of Torchwood where no one died? The planet became overrun with sick people.
If cells didn’t die this would happen to our bodies. Cells can be damaged in soooooo many ways, UV radiation, chemicals, even caffiene. Cells have “Checkpoints” that can stop a cell from dividing. Imagine the checkpoints like a security at an airport and the damage is a bomb in a suitcase. The security see the bomb and stop it going any further. It is then taken way and blown up. Cells who carry damage to DNA will not get passed a checkpoint and this will start a cascade of protein interactions resulting in cell death.
When these checkpoints go wrong, thats when cancer can occur. Its not just damage to the cells either – if the checkpoints go wrong then cells that should have died continue to divide. Imagine the security guard at the bag scanner suddenly dissapeared, the bomb will get through that checkpoint every time. The tumour suppressor protein TP53 is one of these checkpoint proteins and when it is damaged or lost the cell can not stop cell division and the cell keeps on dividing and dividing and dividing resulting in cancer. Thats all cancer is – uncontrolled division of usually controlled cells.
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Leisha Nolen answered on 12 Jun 2012:
Cells can definitely kill themselves and we better be happy they do! Did you know there were webs between your fingers before you were born? Like a duck, we all have skin between our fingers before we are born. As time goes by the cells in this extra skin die and by the time we are born we have normal fingers!
Comments
Austin commented on :
Nice summary, Judith.
Apoptosis is incredibly important, and one of the biggest ‘new’ discoveries (or at least ‘things we didn’t realise were important, but that we now can see are’) over the thirty years I’ve been working in science.
A lot of what we know about it started with people studying the nematode worm C Elegans – the worm only has about 1000 cells and scientists have counted all of them (!), including the ones that die off / commit suicide as part of normal development. Counting the cells (down a microscope) is actually what Sir John Sulston won the Nobel Prize for, though he is much more famous for running the British end of the Human Genome Project.
The coolest apoptosis experiment I ever read about (and used to talk about in my lectures) was one where they deleted one of the key genes for apoptosis in cancer cells, and showed that cells then couldn’t kill themselves properly when they were damaged (e.g. by anti-cancer drugs). But then if they put the WORM version of the gene into the HUMAN cell (to replace the human gene they’d deleted) then the cell could commit suicide (apoptosis) just fine. I always thought that was an amazing demonstration of how similar the worm and the human gene/protein were. If you think of all the evolution that divides humans from a 1000 cell flatworm, to think that that gene is so similar that the worm version can ‘sub in’ for the human one is… mind-blowing.
Judith commented on :
Anouk, I wouldn’t DARE forget about apoptosis or p53 (TP53) as it was discovered by David Lane, a former colleague in Dundee! So I had an unfair advantage on that question!
Judith commented on :
Had completely forgotten just how cool apoptosis is:
http://www.youtube.com/watch?v=xdLPpdoU2Nc
And I meant that David discovered p53, not apoptosis itself. Just to be pedantic….
Anouk commented on :
I love that I’m learning stuff too 🙂