Finding may spike cancer cells

British scientists have unravelled a key mechanism in cancerous cells that could help them to overcome drug-resistant tumours.

They have identified the structure of a molecule called P-glycoprotein, which, like a miniature machine, pumps chemotherapy drugs out of cancerous cells before they have a chance to kill them.

"If we could understand and then disrupt the machine's mechanism, we could have an effective way of knocking out the pumping action," said Professor Chris Higgins, of Imperial College, London.

"Without the ability to get rid of anti-cancer drugs, tumours would once again be vulnerable to attack."

Most types of cancerous tumour respond to chemotherapy, but they can later develop resistance to the toxic drugs.

In research published in the European Molecular Biology Organisation Journal, Professor Higgins and a team of scientists describe the three-dimensional structure of the P-glycoprotein for the first time.

Their knowledge of its structure will allow scientists to develop drugs to block its action.

"There is nothing more frustrating than treating cancer cells with drugs that we know can be effective, only to watch them get pumped out of the cells before they have a chance to work," said Oxford University's Dr Mark Rosenberg, who collaborated on the molecular research.

"But now that we know the exact three-dimensional structure of one of cancer's pumps, we can start designing drugs to lock on to the molecule and stop it from working."

Cancer is a leading cause of death in most industrialised countries.

Worldwide, an estimated 10 million people are diagnosed with cancer each year and about 6.2 million people die of the disease, says the World Health Organisation.

Lung, stomach, liver, colo-rectal and breast cancer are the biggest killers.

Surgery, radiotherapy, chemotherapy and hormonal treatments are the main ways of tackling the disease.

- REUTERS

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