Cancer treatments can be delivered straight to tumour cells using tiny magnets, saving healthy cells from their toxic side-effects, researchers said yesterday.
The new drug delivery method is expected to begin human trials within two years, and could dramatically improve the experience of chemotherapy.
In experiments on mice, researchers filled immune cells with iron particles and were able to guide them in large numbers around the body towards tumour cells.
They said the immune cells could be modified to deliver standard chemotherapy drugs or even emerging treatments such as gene therapy, and could also be used to treat other diseases. This would make sure drugs were focused in the places they were needed in the body, reducing the dose needed and the side-effects.
Chemotherapy usually involves flooding the body with toxic drugs that kill rapidly dividing cells more effectively than healthy cells. Gene therapy, on the other hand, is aimed at delivering DNA to tumours which then produces toxic proteins that kill cancerous cells.
Scientists from the universities of Sheffield, Keele and Nottingham used monocytes, white blood cells that attack cancers, to carry therapeutic genes into tumours. In addition, the monocytes were filled with iron particles.
"Monocytes go around the body engulfing foreign particles - that's their job, and they'll engulf the [iron] particles very readily," said Claire Lewis, of the University of Sheffield. "When you reintroduce them into the body, they will circulate naturally in the bloodstream. You can pull a lot more of them up into the tumour by creating a magnetic field around the tumour."
The next step in the experiments, described in the latest edition of the journal Gene Therapy, is to use MRI techniques to create a magnetic field around deep tumours in the liver, kidneys or brain, "so that we can target these therapeutic cells to areas that are normally quite resistant and are fatal for the patient," Lewis said.