Clue to "blocking" bowel cancer

Scientists say they have found a way to prevent bowel cancer from growing.

The removal of a cell "switch" in mice stopped growth of lesions in the bowel that can turn cancerous with time.

The Vanderbilt University team hopes a drug that blocks this switch, which has been developed in France, could have the same effect in humans.

The scientists told Cancer Cell journal they planned to test this drug in mice. Cancer Research UK said it was a long way from human therapy.

Blocking cancer growth

Cells have receptors that can be turned on and off to control different processes in the body.

A receptor called PPARdelta is thought to be important for the development of tag-like lesions of bowel tissue called polyps.

Bowel polyps are generally harmless but can become cancerous with time, leading to full-blown bowel cancer.

A hormone-like substance called prostaglandin E2 (PGE2) has also been linked to the development of polyps and bowel cancer.

Dr Raymond DuBois and colleagues investigated the relationship of these receptors and substances in mice.

They bred mice with a certain genetic mutation that made them prone to developing polyps in the bowel.

When these mice were exposed to PGE2 they had many more polyps than they normally would have.

The scientists then mated these mice with mice that lacked a gene for PPARdelta.

The offspring would then be able to develop polyps but these polyps would not contain any PPARdelta receptor, they reasoned.

When these mice were exposed to PGE2 they had the usual number of polyps.

This shows PPARdelta is important for PGE2 to encourage polyp growth and, therefore, cancer growth, according to the scientists.

Drug research

"Now we can really focus on key components," said Dr DuBois.

His team plan to test a French drug that has the same effect as knocking out the gene for PPARdelta. This work will begin in mice.

Dr Elaine Vickers, science information officer at Cancer Research UK, said: "Several scientific studies have suggested a role for PPARdelta in the development of polyps in the bowel.

"This work has increased the evidence that PPARdelta is important in polyp formation.

"But this research is still at an early stage, and there is a long way to go before this work could be applied to humans."

Colon Cancer Concern welcomed the study and said it would be important for people who are prone to bowel cancer.

A spokeswoman said: "Genetic or familial cancers are particularly challenging and require as much research as possible to improve the long term survival for these specific patients."

Source: BBC News