Age link to gene that fights tumours

A gene that prevents cancer can cause premature ageing symptoms when it goes into overdrive, say researchers.

Mice genetically engineered to have an over-active version of the gene, called p53, developed fewer tumours, but they also died younger than normal mice, the researchers found.

"Ageing and tumour suppression may be opposite sides of the same coin," said Dr Lawrence Donehower of the Baylor College of Medicine in Houston, Texas, who led the study.

The p53 gene is known to be involved in a range of cancers and stops a cell from dividing.

When it gets damaged, a cell can divide uncontrollably, growing into a tumour.

Dr Donehower and colleagues developed mice with an over-active gene. suffered fewer tumours than normal mice. But there was a price.nte

They lived just 96 weeks, compared with 118 weeks for normal mice of the same breed.

The findings are reported in the latest issue of the science journal Nature.

The mutants also looked old - they were thin and had reduced muscle mass, they developed hunched backs, brittle bones and any wounds they had healed slowly.

"These mutant mice show a lot of reduced cells in their organs - the organs become smaller with age," Dr Donehower said.

He believed p53 might be involved in the activity of stem cells, the body's master cells that are the source of replacement cells and tissues.

"P53 may become active in stem cells and may reduce division later in life," he said.

"We think as the animals get older, more aggressive p53 in the mice may prevent the stem cells from replenishing."

So as the p53 gene stopped cells from becoming cancerous, as a side-effect it could also stop new cells from being born.

More experiments must be done to pin this down, but it showed an intriguing role for p53.

Other experts said the implications could mean bad news for young cancer patients.

"These results raise the disturbing possibility that the genotoxic agents used to treat cancer in young individuals might accelerate age-related disorders later on," wrote Gerardo Ferbeyre, of the Universite de Montreal in Canada, and Scott Lowe, of Cold Spring Harbour Laboratory in New York.

Dr Donehower said he doubted that.

"It makes a certain amount of sense but cancer treatments are so transient, so short term, that I don't think they are going to have any major effects."

- REUTERS

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