Thursday 20 June 2002
A major advance at The Institute of Cancer Research, published today in the journal Nature, will help scientists to further understand how they can exploit an important difference between the chromosomes of normal and tumour cells.
Professor Stephen Neidle and colleagues at The Institute of Cancer Research, funded by Cancer Research UK, analysed the structure of telomeres (single strands of DNA located at the tips of all human chromosomes). Telomeres are degraded with time in most normal cells, but in tumour cells they are not viable. Scientists discovered that this telomeric DNA was organised in a very different way than previously thought.
Professor Neidle said, "It is crucial to study the structure of telomeric DNA because if we know how it is arranged and folded within human cells then we will have a better insight into how we might develop new drugs which could target it much more reliably and selectively than before and have an effect only in tumour cells."
"This is a significant discovery because the structure of the DNA in the telomeres is fundamentally different from what we expected from previous research. We now have a much better understanding of their architecture."
Telomeres' main function is to give protection to the ends of the chromosomes, stopping them fusing or combining inappropriately. In protecting the chromosomes, the telomeres become shorter after each round of cell division, but not in tumour cells.
The structure of telomere DNA was determined by first making crystals of the DNA involved, and then bombarding these crystals with X-rays. By analysing how the X-rays are deflected by the crystals, the physical positions of the individual atoms within the DNA were determined, and finally the complete architecture of the telomere DNA molecule could be described.
The new DNA structure suggests a straightforward path for telomere folding and unfolding. The four strands of telomeric DNA come together to form an arrangement known as a quadruplex, which the scientists found to be flat and propeller-shaped, and which can form long stacks one on top of the other with their 'blades' sticking out on all sides. This should make them easily recognizable by specific drug molecules, and is very different from the structure of the DNA double helix, which is how the rest of DNA in chromosomes is organised.
Professor Peter Rigby, Chief Executive of The Institute of Cancer Research said, "This discovery has major implications for drug development which is one of our main aims. It should accelerate the process and the discovery of new drugs that could help treat many different cancers."
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For further information on this study, contact Alison Morgan at The Institute of Cancer Research on 020 7970 6028 Out of hours: 0778 8427856
Notes to editors
- The Institute of Cancer Research is a centre of excellence with some of the world's leading scientists working on cutting edge research. It was founded in 1909 to carry out research into the causes of cancer and to develop new strategies for its prevention, diagnosis, treatment and care. The Institute works in a unique partnership with the Royal Marsden NHS Trust, which enables scientific discoveries to be translated quickly into patient care.
- Cancer Research UK is the largest independent cancer research organisation in the world, spending an annual £176 million on scientific research into the causes, treatment and prevention of cancer. The combined expertise of over 3,000 of the UK's top scientists, doctors and nurses places us at the forefront of cancer science and new treatment discovery. It supports research throughout the UK in universities, hospitals and institutes and in our own research centres. It relies almost entirely on voluntary donations to fund this work.
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