I am optimistic that we could soon have targeted treatments that spare cancer patients the side-effects that many suffer today

Dr Nicol Keith

Designed by a team of scientists funded by the Cancer Research Campaign, the gene therapy system appears to target cancer cells while leaving healthy tissue unharmed.

Optimistic

Team leader, Dr Nicol Keith, said: "I feel very strongly that our research represents a potential breakthrough, with implications for the treatment of a variety of common cancers.

"People have discussed similar kinds of gene therapy system before, but we have now made significant progress by moving from talking about the theory to actually killing cancer cells in a very efficient manner.

"With a bit of genetic trickery, we have managed to fool cancer cells to their doom without harming normal cells.

"I am optimistic that we could soon have targeted treatments that spare cancer patients the side-effects that many suffer today."

Certainly gene therapy holds the promise of saving many lives from cancer in the future

Professor Nick Lemoine

The technique works by fooling a cancer cell into "switching-on", or activating, a gene which will in fact destroy it.

In 80% of human cancers the gene telomerase is switched on to ensure the cell's survival and to allow it to divide beyond its allotted time span.

The scientists, from the Beatson Laboratories at Glasgow University, took a copy of the "on-switch" for telomerase and wired it to another gene, called nitroreductase.

The cancer cells were then tricked into switching on the nitroreductase, which is a very effective cancer treatment, thinking it was telomerase.

Nitroreductase works by converting the normally harmless drug CB1954 into a toxic product which rapidly kills cancer cells.

But non-cancerous cells are not able to "switch-on" telomerase and therefore are unable to switch on the genetic treatment either - saving them from damage.

'Realistic treatment

Dr Keith said: "Using a sleight of hand we can convince cancer cells that they are switching on the telomerase - which is essential to their survival - when in fact they are actually switching on a gene that will ultimately kill them."

Professor Nick Lemoine, head of Molecular Oncology at Imperial Cancer Research said: "This research is positive progress towards making gene therapy a realistic treatment in the clinic.

"Using the telomerase gene is an interesting area of research and the next step forward will be to prove we can target cancer cells selectively in people.

"Certainly gene therapy holds the promise of saving many lives from cancer in the future."

The system was also shown to work with other genes apart from nitroreductase, also making it very versatile.