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Last Updated: Friday, 18 January 2008, 15:34 GMT
Lifestyle 'a big impact on drugs'
Chemotherapy
Diet may affect the way drugs work
Lifestyle could play a big role in the effectiveness of the latest generation of drugs aimed at treating cancer, a scientist has suggested.

Tests on yeast found knocking out key genes could harm it, or make it thrive, depending on the surrounding chemicals.

The Manchester University research, published in Nature Genetics, implies diet might affect the way gene-blocking drugs work in us.

Other experts point out that the theory has yet to be proven in humans.

It is possible that a human diet could change the cell environment and perhaps have some effect
Dr Daniela Delneri
Manchester University

The research centres around an region of the cell's genetic code called the proteasome.

While its function isn't fully understood, it helps keep the cell working properly by getting rid of unwanted proteins.

In some cancer cells, this regulation role appears to have gone wrong, and some modern types of cancer drugs - 'proteasome inhibitors' - work by blocking the action of some of its genes.

The Manchester University researchers looked at the way that this drop in "gene dosage" worked using an experiment in baker's yeast, which shares many genes with humans.

Every cell has two copies of each gene, but they changed the cell so that it had only one of each, then placed it in a number of different environments, rich or poor in different chemicals.

The expectation was that the cells with only half their normal complement of genes would not fare well, but in some cases, the reverse was true.

If there was plenty of nitrogen available to the yeast cell, the removal of the genes caused it to struggle, whereas a lack of nitrogen led to a thriving cell, despite the lack of genes.

Protein-rich

Dr Daniela Delneri, who led the study, said she was "very surprised" to see this.

She said that it opened the theoretical possibility that human cancer cells might be able to cope better with the proteasome inhibitors depending on the amount of nitrogen available to them.

This is an interesting piece of science, but it's far from certain whether its findings will hold true in humans
Cancer Research UK spokesman

If this were true, a protein-rich diet, she said, might increase the effect of anti-cancer drugs, whereas not eating enough protein could do the reverse.

"What this shows clearly is that changing the environment can have a significant effect on the outcome.

"It is possible that a human diet could change the cell environment and perhaps have some effect."

She said the next step would be to try the same experiment using actual proteasome-inhibiting drugs to see if the same effect could be found, before conducting animal experiments.

Big differences

A spokesman for Cancer Research UK said that it was important to remember the differences between a yeast cell in the laboratory and a cancer cell deep inside a human.

"This is an interesting piece of science, but it's far from certain whether its findings will hold true in humans.

"Yeast are simple, single-celled organisms that have to respond quickly to changes in their surroundings.

"But humans are vastly more complicated and devote a lot of energy to maintaining a stable internal environment.

"This might mean that the way our cells respond to nutrients is very different, despite the many basic similarities between individual human and yeast cells."

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