Here’s a riddle for you – what does DNA and an MRI have in common? Both are very tasty when the researchers from Oxford Cancer Research UK centre take their science know-how into the kitchen. This is the Great Science Cake Off Explained – Oxford.
This month saw the first ever CRUK Great Science Cake Off and I am delving into the science behind these amazing creations. Today we are drooling over the cakes from Oxford’s CRUK centre where research focuses on breast, skin, gastrointestinal and urological cancers (bladder, prostate, kidney and testicular cancers). Researches in the Oxford centre also have expertise in radiotherapy research and the genetic and lifestyle factors that put us at risk of cancer. Now’s the time to find out what all that brain power can do in the kitchen.
Our first cake looks at how DNA is packaged in our cells. It has been calculated that if you unravelled the DNA in a single human cell it would stretch to the moon, so how can it all fit into a single cells that is so small you could fit tens of thousands on the head of a pin, and how does it not get tangled? The answer is packaging proteins that the DNA is wrapped around, it is a bit like the spool that sewing tread is spun around. If you took all the tread off a spool it would probably end up with a few knots in and take up more space than when it was packaged.
The spool that helps wrap up and package your DNA is actually made out of a type of protein called histones. Eight of these histone proteins are required to make up the octamer that the DNA is wrapped around. Each layer of this cake has four “histone” quarters in pink, blue yellow and green and the white DNA strand is wrapped around two layers of cake. But the histone protein isn’t just made up of the cake quarter, it also has a cupcake “tail” that has an important role in for how the histone packages DNA. Finally on top of the cake the “double-helix” structure of DNA is shown in more detail.
It has been calculated that if you unravelled the DNA in a single human cell it would stretch to the moon…
We now know that the way the DNA is packaged affects how easily it can be used to make proteins. If you imagine you have a bookshelf with lots of cook books but only one in reach – the others are too high up to get down – you are more likely to cook something from that book. In the cell, if the DNA is the “recipe” with the information for how to make all the different proteins in the cell, the DNA that is less tightly packaged is more likely to be used to makes the proteins. Scientists now know that alterations in the way the DNA is packaged – called “epigenetic” modifications – can contribute to cancer and researchers in Oxford have been studying the enzymes that change the “tail” of the histone proteins, which effect the way the DNA is packaged, and lead to cancer.
The next cake we are going to ‘sink our teeth into’ is looking at the sub-cellular (smaller than a cell) level – zooming in on a single protein to investigate what it look like. Scientists have a few clever techniques to look at the structure of proteins – but that will have to be a topic for another blog post.
Understanding what a protein looks like can help scientists to figure out how the protein works and, and in the case of cancer, why it is now working properly. This cake shows a protein that is made of two parts – a green and blue part. Both parts of this “dimer” protein are helical and look like a cork screw. We also know from this cake that the protein dimer lives in the cell membrane.
Cell membranes act like the rubber of a balloon that keeps the air in. The membrane is made of lots of molecules that have two parts – a lipid head (red) and fatty acid tail (yellow). These molecules form a layer a bit like a butter sandwich with the yellow fatty acid part of the molecule on the inside and lipid bread part on the outside. This protein sits in the middle of that membrane sandwich like a skewer. Scientists in Oxford have managed to find out what this protein dimer looks like in the hope they can better understand what role it has in breast cancer.
Zooming out to have a look at some cancer cells in the next cake. Recently scientists have learnt that not all cancer cells are the same. Some cells in a tumour have different characteristics such as an increased resistance to radiotherapy and ability to make other cancer cells. These cells are called cancer stem cells and they are also better at moving to other areas of the body by squeezing between cells and invading surrounding tissue. In this cake we can see these special cancer stem cells as green rectangles amongst other normal cancer cells (orange). The green special cells in this cake are also making little green dots or “exosomes” that they release to help communicate with other cells.One of the challenges that scientists now face is to better understand the different cells in a tumour so the therapies that are developed can better kill every last cancer cell and reduce the chance of the cancer coming back.
The final cake we are going to look at from Oxford is representing the ARC-II clinical trial. This trial aims to combine radiotherapy with the chemotherapy drug nelfinavir to treat pancreatic cancer. The cake shown a MRI image through the body from above the belly button (top of cake) to the back – you can see the spine in white at the bottom of the cake. In the middle of the cake we can see an abnormal red dot in the middle of the pancreas – this pancreatic cancer has been circled in yellow. The clinical trial is hoping to find out if the chemotherapy drug makes cancer cells more sensitive to radiotherapy. And, if so, the researchers hope to demonstrate that they can improve the treatment of pancreatic cancer. You can find out more about the ARC-II clinical trial on the Oxford University webpages.
Congratulations to all the bakers, all the cakes from Oxford were amazing and demonstrated some really tough science. This blog will continue as we look at the entries from CRUK centres in Manchester, Birmingham, Glasgow, London, East Scotland, Cardiff, and Southampton delving further into the wierd and wonderful world of cancer biology. Can’t wait for the next post? You can view all the cakes in the 2013 Great Science Cake Off on Pinterest.
@Beckieport is a CRUK funded PhD student in the final stages of her doctorate studying how viruses cause cancer. If you want to know more about the research and events happening at the CRUK centre in Oxford you can follow Rebecca (the research engagement manager) on twitter, @CRUKOxford, or find out more about their world class research on the centre website. As always comments and suggestions on this blog are encouraged. This is a personal blog and is not endorsed by CRUK – however I hope you like it anyway.