Hopes boosted for anti-cancer drugs

Fresh research could improve the action of anti-cancer drugs by keeping them inside tumour cells for longer.

Scientists have worked out the structure of a molecular pump which cancer cells use to dump toxic chemicals. The pump helps protect tumours from chemotherapy, eventually getting rid of anti-cancer drugs as quickly as they are administered. The ability to block them would greatly enhance the chances of successful treatment.

Scientists supported by the United Kingdom's Cancer Research Campaign and Medical Research Council have now taken a major step towards this goal. They have identified the structure of a pump molecule called P-glycoprotein which is present in small amounts in healthy tissue where it plays a role in normal metabolic processes.

Some cancer cells develop high amounts of P-glycoprotein which protect them from chemotherapy drugs. Until now, scientists had only a vague idea what the molecule looked like and even less understanding of how it worked. In the new study, researchers examined tiny crystals of P-glycoprotein under powerful electron microscopes to discover its size and shape for the first time.

Dr Mark Rosenberg, one of the investigators at the University of Manchester Institute of Science and Technology, England, said: "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.

''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. We have also gained a detailed understanding of how the pump works and this too will have implications for drug design.''

For more information got to the University of Manchester Institute of Science and Technology website.