January 24, 2007

'Super-chickens' offer hope of cheap drugs

A FLOCK of chickens genetically modified to lay eggs that could help produce cancer-fighting drugs, has been bred by a team of Scottish scientists, it emerged yesterday.

Researchers at the Roslin Institute near Edinburgh have successfully bred three generations of hens, each capable of producing eggs containing high levels of proteins that could be the basis of new drugs.

Experts believe the breakthrough could allow the production of treatments for cancer, MS and other illnesses at a fraction of the price the NHS pays now.

But anti-GM campaigners expressed concern over the so-called transgenic hens, details of which are published in the Proceedings of the National Academy of Sciences.

The scientists at the Roslin Institute - where the cloned sheep Dolly was created - used a common breed of egg-laying hen known as ISA browns. The aim was to create a chicken capable of laying eggs containing medicinal proteins that could be used to make drugs.

The team, led by Dr Helen Sang, created an artificial gene containing the human protein they wanted to reproduce in the eggs. This was put into a virus which was injected into the embryo inside an egg.

Dr Sang said the team was trying to put a new gene into the chicken to mimic human DNA, to create proteins useful in the treatment of human disease. Some of the chickens born as a result of the technique will be able to lay eggs that contain the desired proteins. The proteins could then be extracted from the white of the egg and used to develop drugs.

The team has so far focused its efforts on creating proteins which could be used to treat MS and skin cancer.

Dr Sang said chickens producing high levels of the proteins in their eggs had been bred several generations on from the original hen. "It does take a long time to do this kind of work, and then you suddenly realise you have actually achieved something important," she said.

But Dr Sang said it could be some time before drugs created using the technique were on the market. "It is a long process and clinical trials of drugs take at least five years," she said.

The Biotechnology and Biological Sciences Research Council (BBSRC), which sponsors the Roslin Institute, welcomed the developments.

Professor Nigel Brown, director of science and technology at the council, said: "I am delighted to see the practical outcomes of Dr Sang's work, the original development of which was funded by BBSRC more than a decade ago.

"To have developed a genetically stable line of chickens producing a therapeutic protein is a significant achievement.

"It bodes well for the future risk-free production of therapeutic products that are identical with a natural human protein."

But Pete Riley, from GM Freeze, which highlights concerns about genetic modification of food and animals, expressed doubts about the work.

"We are very concerned about this from an animal-welfare point of view," he said. "Dolly the sheep had a very short life and suffered serious health problems.

"We need to know a lot more about what we are doing with this type of technique. We would be very, very cautious.

"There are some major moral and ethical issues that need to be debated."

Mr Riley said scientists needed to look for ways of preventing diseases rather than focus on using GM to find treatments.

"We need to look at lifestyles, diet and the environment to look at the causes of cancer, and not be swept along by scientific euphoria about the drugs," he said.

But Dr Mark Matfield, scientific advisor for the Association for International Cancer Research, said such work was necessary to find new treatments for cancer. "I can understand people's concerns, but they are misguided. Nature has been genetically modifying plants for all of evolution," he said.

Dr Matfield said the research was "very promising".

He added: "A big area for cancer treatments is what we call biological drugs. These are drugs that come from a natural source, in this case chickens, rather than synthesised molecules. After proper safety testing, these drugs could be available in just a few years.

"The potential to produce lower-cost drugs is also a big plus for the NHS."

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