From beer and bread to cancer research: using brewers yeast to unlock the secrets of cancer genetics

Alexandra Weirich, our SIN Intern, guest blogs about a recent UK researcher’s visit to the University of Ottawa:

 Dr. John Diffley from the UK’s London Research Institute, travelled to Montreal and Ottawa last week to meet with scientists at the University of Ottawa and McGill and discuss their research findings. Dr. Diffley shared what he has discovered about DNA replication (how cells create copies of their DNA) by studying how this occurs in brewing yeast. He says that this process is so exact and complex he finds it amazing that two thirds of the population don’t develop cancer.

All the genes that define your characteristics, from your eye colour to whether, or not, you are likely to develop cancer, are encoded in the DNA inside each of your cells (each cell contains a full copy of your DNA, or to look at it another way, instructions on how to create another you). Every day, most (but not all) of your cells will replicate (create a new, perfect copy of themselves), copying the entire 2 meters of DNA they contain exactly once.  During this process, the cell will divide that DNA exactly in half so that at the end of the process there are two cells that are healthy exact copies of each other. For reasons that scientists haven’t completely figured out, sometimes cells don’t do this exactly right, resulting in genes that are lost, moved around, or copied too many times. This can lead to the development of cancers that are difficult to treat.

Dr. John Diffley is the director of Clare Hall Laboratories at the London Research Institute. This group is investigating the different mechanisms/machinery of DNA replication in hopes of understanding how this process can go wrong and result in cancer. Dr. Diffley’s group is using budding yeast (also used to brew beer and make bread) as a model for how human cells copy their DNA.  They try to understand how the machinery that builds new DNA is turned on and off. Dr. Diffley explained that he works in yeast because it is simpler and faster to do experiments on yeast cells than it is in mammalian cells grown in the laboratory (tissue culture). A population of yeast will double in 70 minutes while it take mammalian cells ~ 24-48 hours. When his lab makes a discovery in yeast, it is verified in tissue culture, to see if the findings hold true in mammalian cells. If all these experiments had to be done directly in tissue culture, it would take us another 30 years to figure out what we already know about DNA replication and cancer.

Dr. Diffley’s work is considered ‘basic research’ because it has no direct medical application; he tries to understand how cells grow and make copies of themselves rather than testing how well treatments can kill cancer. Although some controversy exists over whether governments should fund basic (blue skies) research, Dr. Diffley explains that we can’t anticipate how important discoveries in basic science will be. He points to Ribonucleic Acid interference (RNAi) as an example. RNAi is a molecular chain that can interrupt the cellular machinery that expresses genes, like throwing a wrench in the works. It is a very specific way of turning certain genes off. The right wrench could be used to turn off cancer genes or viruses. This is a naturally occurring process in the cell but nobody had a clue about it until it was discovered in 1998 through basic research on a microscopic worm (C. elegans). Now, this is being investigated as a possible treatment for cancer, viral infections like HIV, and gene therapy.

Scientific discoveries like these rely heavily on international collaboration to advance. No single research group has all the expertise and resources to take an experiment from the basic level of yeast and/or worm research to treatments for disease in clinic. The UK and Canada Prime Ministers recently endorsed a joint declaration that aims, in part, to encourage future collaboration on research and stimulate scientific advancement for economic growth.

* – RNA, or RiboNucleic Acid is a molecular chain very similar to DNA. If DNA is a library of all your genes, RNA is like a photocopy of pages in the library. The RNA photocopy is used as instructions to tell the manufacturing machinery of the cell what to build.