Source: www.telegraph.co.uk
Author: staff

The space-age technology, which uses microscopic iron particles to heat up and destroy tumours, may be ready for clinical trials in as little as three years.

Different teams of UK scientists have been working together on the research, which could bring new hope to patients who are no longer responding to standard therapy.
In future the ”nanomagnet” cancer treatment may even be administered in GP surgeries or out-patient clinics. Crucially, the scientists believe it will be highly cost-effective.

The technique literally ”cooks” cancer cells as if they were in a microwave oven. But instead of microwaves, a rapidly changing magnetic field is generated by the paddle-shaped ”wand”. This heats up thousands of iron oxide ”nanoparticles” placed inside the tumours. Heating the cells by only 5-6C is enough to send them into shock and kill them. Meanwhile, surrounding healthy tissue in which the iron oxide particles are absent is left unharmed.

A major part of the research has involved finding ways to target tumours with the nanoparticles. Two approaches have been explored, one using bone marrow stem cells and the other using antibodies to ferry the particles to cancer sites.

A major advantage of using a biological version of ”iron filings” in the therapy is that they can easily be tracked by a magnetic resonance imaging (MRI) scanner. Doctors will be able to map exactly where the nanoparticles – and the cancer – are situated in the body. The ”wand” can then be held over the hidden tumours to destroy them.

An average weekly treatment session with the ”wand” might take half an hour. Professor Kerry Chester, one of the scientists at the University College London Cancer Institute, said: ”We know that heat kills cancer cells, but you can’t use it systematically without killing the patient.

”The important thing with this approach is that you can see where the nanoparticles go. You can see them and use them for targeted therapy.”

Colleague Quentin Pankhurst, professor of physics at University College London and director of the Davy-Faraday Research Laboratories at the Royal Institution, said: ”Once the iron oxide particles are there the treatment can be repeated again and again.

”I would love to see this technique used in GP surgeries or out-patient clinics. It would make the whole business of treating cancer much easier.”

Iron is generally non-toxic and involved in a plethora of natural processes in the body. It plays a key role in transporting oxygen through the blood. The new therapy would employ tens of thousands of iron oxide nanoparticles, but since each one measures eight to 10 millionths of a millimetre, the total amounts are very small. Around half a milligram of iron might be used to heat-treat an average tumour. In comparison, the human body normally contains the equivalent of a six inch nail’s worth of iron.

For reasons scientists do not fully understand, stem cells – the immature ”mother” cells that develop into different kinds of tissue – have an affinity for cancer. The scientists are exploiting this property in bone marrow ”mesenchymal” stem cells to deliver the iron oxide particles.

They found that the stem cells naturally absorb the particles when they are ”fed” them in their culture medium. Injected into the bloodstream, the stem cells head for cancer sites and integrate themselves into the tumours, carrying the nanoparticles with them. In experiments with mice, the researchers have used iron-packed mesenchymal stem cells to target and heat up tumours under the skin. A variation of the research has involved using the same stem cells to transport a cancer-killing protein to tumours. This treatment was able to eliminate the spread of lung cancer in 40% of mice with the disease.

Another strategy is to use fragments of antibodies – proteins used by the immune system to attack foreign invaders – to carry the nanoparticles. Antibodies can be designed to attach themselves onto specific molecular sites on cancer cells.
The antibody agents, made in yeast, are covered in a special ”stealth” coating which prevents them being spotted and attacked by the immune system.

The three-year research project has been financed with a £1.6 million ”Grand Challenge” grant from Research Councils UK. Although the work is still at a very early stage, the scientists expect to be ready to test the treatment on cancer patients at the end of that time.

Lung and head and neck cancer patients are likely to be the first to receive the therapy. Both have a poor prognosis once the cancer has reached an advanced stage and is no longer responding to standard chemotherapy. It’s thought nanomagnet treatment would provide a potential extra life-line after other strategies have failed.