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EDITIONS
 Monday, 20 January, 2003, 18:59 GMT
Discovery may combat resistant tumours
Lab work
Scientists have identified a key molecule
Scientists have uncovered a possible reason why some tumours respond less well to drug treatment.

They have found that high levels of specific molecule within cancer cells seem to block the effect of drugs such as Taxol, which are used to treat a number of cancers in their later stages.

Testing tumours for the molecule might help us to predict how effective Taxol treatment is likely to be

Professor Ashok Venkitaraman
So far the work has been carried out in the laboratory, but tests will now take place on cancer patients.

If confirmed, it could lead to a new test to predict whether drugs such as Taxol are likely to be effective on individual patients.

And it might also lead to new forms of treatment.

Drug resistance is one of the biggest problems facing cancer doctors.

Supplementary drugs aimed at increasing the effectiveness of chemotherapy could save many lives.

Genetic engineering

The researchers focused on a molecule called AURORA-A which is found at higher than normal levels in up to half of breast and bowel tumours, and in many other kinds of cancer.

They genetically engineered cervical cancer cells with the gene for AURORA-A in order to increase levels of the molecule.

When treated with Taxol, only about half as many engineered cells were killed by the drug as non-engineered cells.

Lead researcher Professor Ashok Venkitaraman said: "High amounts of AURORA-A seemed to make cancer cells less sensitive to treatment.

"Testing tumours for the molecule might help us to predict how effective Taxol treatment is likely to be.

"Of course, our findings will need to be confirmed in cancer patients before it is clear that such a test will work.

"Our work raises the additional possibility that new drugs which inactivate the molecule could boost the response of cancer cells to treatment."

Alarm mechanism

Normally, a cell can only divide if it has correctly shared out all its genes, ensuring each new cell receives a complete set.

If there is a problem with the process of sharing out genes, an alarm will be triggered and the cell will not divide.

Drugs like Taxol work by attacking the system responsible for sharing out genes and so triggering the alarm, sending cancer cells to their deaths.

But in the study, cells with high amounts of AURORA-A seemed to over-ride the alarm and continue to divide, even when their genes were not correctly shared out.

This ability to ignore the alarm could make them resistant to Taxol-type drugs.

Sir Paul Nurse, chief executive of Cancer Research UK, said: "Taxol is a valuable drug for many patients with late-stage cancer, so finding ways of improving its effectiveness would be an important development."

The research is published in the journal Cancer Cell.

See also:

30 Mar 00 | Health
23 Sep 02 | England
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