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Asked by lindseymerrygold to Christine, Edd, Jess, Nicolas, Zara on 14 Jun 2011.
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Edward Codling answered on 10 Jun 2011:
Wooaah hold on there – that’s three questions in one! 😛
1. I am not sure what is going on with Pi but it is a really interesting number – almost magical! If you study maths to a high level you’ll find it appears everywhere. You might know it from geometry of a circle (area, radius, circumference etc) but it crops up in all the different areas of maths. Did you know that Pi is an irrational and transcendental number? (This means we can never write it down exactly!)
2/3. I don’t know much about the science of aging but as I understand things we age basically because the body stops being able to do the cell reproduction and repair that happens automatically earlier in life. Similarly, cancerous cells are basically formed when the body incorrectly replicates healthy cells and they then cause problems within the body.
Studying these processes is extremely important and many scientists are studying these things at the moment. Clearly whatever results they find could have very important consequences for all of us. Some people say that (in theory at least) we could possibly all live to about 900 years old. Do you think this would be a good thing? (what about over-population etc?)
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Jessica Chu answered on 11 Jun 2011:
Hi,
Like what Ed has said, there are a lot of researches going on in this area but it is still in the early stages so no one can give us a answer for that yet! Someone asked a similar question about why people age so I hope you don’t mind me using a bit of that answer to your question 🙂
Question 2)
I don’t know an awful lot about this area of science but I will try tell you a few things I think which might be related 🙂Everyone cells’ go through ageing! Things like free radicals (an atom or a group of atom that have loss one of its electrons so they are highly reactive and will react with anything in our body) can promote ageing as reported by some researchers.
Natural processes that goes on inside our body such as enzyme reactions and phagocytosis (when white blood cells are getting rid of alien molecules that enter our bodies) – these process as well as many more produces free radicals so it will have an impact on ageing!
Free radicals can also be just present in the environment- UV light (sun), ozone, and air pollution (chemicals released from industrial sites). Another thing that will really increase the level of free radicals is by smoking.
The term is Senescence is used to describe cells going through ageing. Not much is known- it could be coded in our genes (short lengths of DNA) and off-set at a certain time.
Also, at the end of every chromosome (DNA that are packed in an ordered way) contain something that is called the telomere.
Telomere is very important because it will shorten after every round of mitosis (cell cycle which involves cell growing bigger, making a new copy of DNA and dividing to produce a new daughter cell). And when there is no more telomere left at the end of a chromosome, the DNA is no longer protected so it breaks down- and the cell dies. The Hayflick limit is the number of division a cell can undergo before it stops so this will have some links with aging.Question 3)
As to your third question- which is very interesting because there a lots of answers to this and many of the possible answers are still being proved by doing more research 🙂Cancer is not a single disease, it is a group of diseases because cancer of the lung and cancer of the brain are very different – they look and grow differently to each other, respond to different proteins signals, requires different treatment and affects the body in different ways.
Some of the main reasons described by D. Hanahan and R.A. Weinberg about why cells become cancerous is because:
1. the cell’s growth signals have gone out of control
The cancer cells are able to make their own growth factors (proteins that send signals to the cell to divide and grow) rather than relying growth factors made from other cells. Or the cells have mutations in the genes that will allow it to keep growing!2. Not responding to growth stopping signals
Normal cells can stop growing when they receive signals from outside the cell tells them to stop. However, cancer cells do not listen to these signals and do quite the opposite, which is to keep growing indefinitely!!! rebellious cells!!3. Fighting cell death signals
Usually, a damaged normal cell will try to fix itself unless the damage is so great that it is impossible to do so then the cell will receive signals to undergo apoptosis (a fancy word but it basically mean cell death). It is normally damage in the DNA (genetic codes).
Cancer cells will not listen to these cell death signals and keep growing with the damaged DNA.4. Unlimited potential to divide
Remember I mentioned those things called Telomeres at the end of chromosomes in cell ageing. Well they have a big role in cancer cells too! Normal cells will stop dividing after they have reached their own Hayflick limit (number of cell division) because telomeres get shorter and shorter after each round of DNA replication until no more telomeres are protecting the chromosome anymore then it will die. Cancer cells can produce its own telomere making enzymes (telomerase) and tell them to keep adding telomeres on to the end of chromosomes after each DNA replication so the cell never have to die!!People in my lab are making drugs to target the enzyme, telomerase!
5. Making new blood vessels
Like normal cells, cancer cells need food and oxygen delivered to them via the blood vessels in order to keep growing.
But unlike normal cells, cancer cells can send signals in its surrounding to stimulate the growth of new blood vessels so they can have food delivered straight to them!! (So like when you order a pizza from dominos- they will deliver the pizza and garlic bread straight to your door!!)6. Moving around the body
Most normal cells will stay in one place in the body until they die and again, cancer cells love doing what they are not supposed to!
So cancer cells have their own mutated enzymes (imagine the enzymes are like a pair of scissors, they are able to cut around the cancer cells from neighboring cells so they are free to move around).
As I mentioned in point 5, the cancer cells already have their own blood vessels so these cancer cells that are free to move around can travel in the blood vessels to pretty much anywhere else in the body and live there (almost like an enormous water slide!!)
At this late stage, this is when the cancer cells are at its most dangerous and can kill people ):I love google- maybe try googling the term ‘telomeres and ageing’,‘ free radicals and ageing’ or ‘carcinogenesis’ – will probably get lots of interesting results!!
I hope this helps! If I didn’t explain it well- feel free to tell me and I will try again 🙂
Jess
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Zara Gladman answered on 11 Jun 2011:
Three questions! That kept me busy!
1. Excellent question. I was never good at maths but who doesn’t have a soft spot for Pi? 😆 The singer Kate Bush wrote a song called ‘Pi’ in which she sings out the digits to music (here it is: http://www.youtube.com/watch?v=kZSHr5E7fZY). And did you know that March 14 is officially Pi day because the first three digits of Pi are 3.14? 3.14 is also the date of Albert Einstein’s birthday. Pi (π) is of course used to find out the geometry of a circle – it’s the ratio of the circumference of a circle to its diameter. For example, if a circle is 1 centimetre across the middle, then it will be Pi (3.14…) centimetres around the outside. It doesn’t matter what size the circle is, the ratio is always the same! Pi is a very old number, even the ancient Egyptians knew it (although not as well as we do now – it has now been calculated to more than one trillion digits!). Pi has real-life applications in architecture, engineering and science: it’s a very important number and remains a bit of a mystery!
2. People age for many different reasons – we still have a lot to learn on this topic! One of the most recent discoveries is that ageing is affected by things called ‘telomeres’ and cell division. Cell division is important because it allows the body grow and repair itself (e.g. get new skin and blood!). The number of times our body can do cell division is fixed, however – once it stops, we get old. Scientists recently found that telomeres – sections of DNA that protect our chromosomes during cell division – get shorter every time a cell divides. This means that a newborn baby will have much longer telomeres than you or me! Once the telomeres get too short, they can’t protect the chromosomes (which contain our important genetic code) any more, and so the DNA is damaged and cells stop dividing. Dolly the Sheep, who was cloned from an adult sheep, died at just 6 years old (most sheep live until 11 or 12). Her telomeres were much shorter than usual for her age, because she was cloned from an adult sheep. Other causes of ageing include exposure to ‘free radicals’, which damage mitochondria (mitochondria are cell ‘power plants’ that produce energy to keep things ticking over). After the mitochondria are damaged, the cell dies. Smoking is also known to speed up ageing of the skin. Making healthy lifestyle choices can help slow down the effects of ageing.
3. A cancerous cell is one that divides uncontrollably, unlike a normal cell that only divides when it needs to for growth and repair. Why does the cell divide uncontrollably? Well, if a cell’s DNA is damaged or mutated then the gene that usually controls how fast the cell divides is switched off. The cell may start to multiply out of control and this can lead to cancer. How does the cell’s DNA get damaged in the first place? Well, there’s a number of causes. Age, lifestyle, viruses, problems with the immune system, inherited genetic faults and exposure to carcinogens (e.g. tobacco, car exhaust fumes, the sun, radiation, asbestos) can all increase the risk of cancer.
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Christine Switzer answered on 14 Jun 2011:
Lots of great answers here already! When I first saw your question I wondered how you would connect pi to curing cancer. With a background in engineering, this doesn’t sound so strange to me. Pi is one of those magical numbers that seems to connect everything, so it would not surprise me at all if it could be used somehow to represent how cancerous cells form and grow or how they can be attacked in the body by a treatment. Some of the maths in my field use pi to represent how water or air moves through the ground. Pi comes from the circle, which is one of the shapes we see in the natural world. Water moving around a soil particle take a path that looks circular, which is how pi works its way into the explanation. We have to understand how water flows through soil so we can understand how contaminants move, too. Long term exposure to certain contaminants may cause cancer, so we need to know how they move in order to protect people from exposure.
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