X-ray beam boosts cancer therapy

X-rays could kick-start genes into fighting cancer, research suggests.

Cancer Research UK scientists have used gene therapy to enhance the effects of radiotherapy and to encourage cancer cells to commit suicide. By using a precise x-ray beam, they ensured the treatment killed only cancerous cells, leaving healthy ones untouched. The research is published in the Journal of Gene Medicine. It is now planned to start clinical trials. That means doctors could achieve the same radiotherapy benefit using much less radiation Professor David Hirst The researchers, based at the University of Ulster in Newtownabbey, used gene therapy to increase levels of a nitric oxide in tumour cells. Nitric oxide performs a range of important functions in the body, but can also kill cancer cells, and enhance the effect of radiotherapy treatment. Raising levels of the molecule throughout the body could be dangerous, so the researchers incorporated a “switch” to make it possible to turn the gene on only in cancer cells. The trigger for the switch was exposure to an x-ray beam used routinely in radiotherapy. The technique was tested in the laboratory on bowel cancer and fibrosarcomas – tumours in the fibrous tissue which holds bones, muscles, and other organs in place. Lead researcher Professor David Hirst said: “We saw up to a two-fold increase in the effectiveness of radiotherapy on tumours. “That means doctors could achieve the same radiotherapy benefit using much less radiation than they would otherwise use, so reducing the side effects of treatment. “Alternatively, they could use the same dose of radiation and kill more cancer cells.” Well targeted The researchers also measured the amounts of nitric oxide in both cancerous and normal cells to see how well they had been able to target the gene therapy. They found that production of the molecule had only been enhanced in tumour cells and the cells immediately surrounding them. Professor Hirst said: “Many scientists researching gene therapy use viruses to deliver genes to cells. “We tried a different approach – using tiny spheres of lipid called liposomes, which interact in a natural way with the lipids in a cell’s membrane. “Each method of delivery has advantages and disadvantages and extensive research on each will tell us which will work best in patients.” The researchers hope their technique will also enhance the effect of chemotherapy. Professor Robert Souhami, Cancer Research UK’s director of clinical and external affairs, said: “Cancer is a complex disease and we need imaginative approaches to combat it.”(Source: Journal of Gene Medicine: BBC News: June 2004)