Bright Idea Could Doom
Cancer and Viruses
Behind the Cancer Headlines®
Cancer and viruses may someday find themselves blinded by
the light of therapies based on recent
A team of scientists including Harry Morrison has developed
a group of rhodium-based compounds that, when exposed to light, can kill tumor
cells and deactivate a virus closely related to the
"We have proven in principle that light and chemistry
together can destroy tumor cells and the Sindbis
virus, a member of a group of viruses that cause encephalitis, fever and
arthritis," said Morrison, who is professor of chemistry and former dean
of Purdue's School of Science. "This research offers hope that someday we
may be able to replace standard chemotherapy drugs with others that are far
less generally harmful to a patient's body and guarantee safe, sterile blood
for transfusions."
The research was published in the journal Inorganic
Chemistry.
Chemotherapy has long made use of platinum-based compounds
to poison cancer cells. These compounds bind DNA in the cellular nucleus and
render the cell unable to reproduce, effectively destroying it. The trouble is, such chemicals also kill many other healthy cells in the
body in the process.
"That's the reason cancer patients often lose their
hair," Morrison said. "Hair cells, like many others in the patient's
body, are also destroyed by these platinum-based chemotherapy drugs. So for a
long time, physicians have sought other substances they have more control over.
If we had a drug we could activate when it reached a certain place in the body
– and nowhere else – it would reduce the stress on the rest of a cancer
patient's system."
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."
SOURCES:
Inorganic Chemistry,
Purdue University (http://www.purdue.edu)