UV light may offer "double whammy" for cancer

LONDON (Reuters) - Using ultraviolet light may one day offer a “double whammy” to kill cancer cells by better focusing antibody-based drugs and triggering the body’s own defenses to eliminate tumors, researchers said on Tuesday.

In two studies with mice, a British team cloaked antibodies -- the immune system proteins that tag germs and cancer cells for elimination -- with an organic oil that blocked them from reacting until illuminated with ultraviolet light.

The researchers used engineered immune system proteins called monoclonal antibodies. They are made to home in on proteins known to be overactive in tumor cells.

When the light unblocked the organic coating, the antibodies switched on and attracted killer T-cells to attack the tumor, said Colin Self, a researcher at Newcastle University, who led the studies.

The technique can help prevent damage to healthy tissue because the covered antibodies are dormant in the body unless lit up, Self said.

“What happens in cancer is the body can’t mount a response to cure cancer,” he said. “This is a way of waking the system up. The antibodies will have their local effect but the hope in all of this is you are bringing in the whole immune system.”

So far there are about 20 approved monoclonal antibody-based drugs used to fight cancer and other diseases.

The technique could work with any of these treatments to fight a whole range of cancers, so long as doctors are able to find a way to shine a light on a tumor, Self said.

“You are getting a double whammy,” he said. “A stronger effect and you can direct the antibody.”

While the studies show promise, the technique is years away for human use and faces a long regulatory road and tough clinical trials before any approval, said David Glover, an independent pharmaceutical consultant.

“There are a lot of hurdles ahead,” Glover told a news conference. “We do not want people to think there is a magic bullet right around the corner.

The next step is initial clinical trials in skin cancer patients, which Self said he hoped to begin early in 2008 provided he could find funding for the research.