Morrison's group experimented with several different chemical complexes that use rhodium, a rare metal, instead of platinum. Eventually they found one compound that was able to damage DNA in living cells in a manner similar to platinum chemotherapy drugs, but with one exception - it remains benign until irradiated with a light beam.
"Anticancer therapies could, in theory, be developed using such photo-activated rhodium complexes," Morrison said. "The interior of the body is dark, but it might be possible to thread a fiberoptic cable through the arteries and flood a tumor with light. Some lasers are also capable of shining through tissue without damaging it, and they might also be candidates for light delivery."
The compound - known as DPPZPHEN, an abbreviation of its long chemical name - also has potential as an antiviral or blood sterilizing agent because it is lethal to any nucleic acid it encounters, including the RNA found in viruses.
"Our study also found the rhodium complex capable of rendering the Sindbis virus inert," Morrison said. "Since blood cells and platelets do not themselves have nucleic acid, they are safe from the compound. But it is potentially possible to purify blood of foreign organisms and viral particles with the rhodium complex and light exposure before it is used in transfusions. It could make for a safer blood supply."
Each of these applications, however, is likely years from development, Morrison said.
"We have only proven in principle that such therapies are possible," he said. "But our experiments have only been on tumor cells in the laboratory, not in living animals
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Contact: Chad Boutin
cboutin@purdue.edu
765-494-2081
Purdue University
24-Aug-2004