Thursday August 30 6:27 PM ET
"Study Suggests New Way to Fight Deadly Brain Tumor"
Study Suggests New Way to Fight Deadly Brain Tumor
NEW YORK (Reuters Health) - New York researchers may have
discovered how a type of deadly brain cancer spreads quickly
through the brain. They say the findings could lead to improved
treatment, since existing drugs may be able to block this
Malignant glioma is an aggressive type of brain cancer that
does not respond well to treatment. Most people with the
disease die within a year of being diagnosed. Exactly how the
deadly disease spreads through the brain has been a mystery.
Laboratory tests have shown that glioma tumors can release
a substance called glutamate, and high levels of glutamate have
been detected around gliomas in the brain. This brain chemical,
known as a neurotransmitter, helps different parts of the brain
communicate with each other. The release of too much glutamate,
however, can destroy brain cells.
A team led by Dr. Maiken Nedergaard at the New York Medical
College in Valhalla suspected that gliomas might spread by
releasing glutamate to destroy surrounding brain cells.
In samples of brain tissue, the researchers detected signs
of glutamate release in areas surrounding gliomas. They also
detected high levels of neuron destruction around gliomas,
suggesting that the release of glutamate paves the way for the
spread of a brain tumor.
In fact, the investigators found that the more glutamate
released by glioma cells, the faster the tumor cells grew.
Moreover, when the scientists treated the cells with
compounds that act against glutamate--including memantine, an
experimental drug that has been tested in patients with
Alzheimer's disease (news - web sites) and other neurological disorders--they were
able to slow down the growth of gliomas.
"Our study indicates that inhibition of glioma glutamate
release or blockade of glutamate receptors may serve as an
alternative strategy in the management of patients with
malignant gliomas," the authors write in the September issue of
But further research is needed, since it is uncertain
whether the findings apply to different types of glioma cells,
according to Drs. Jeffrey D. Rothstein and Henry Brem at Johns
Hopkins University in Baltimore, Maryland.
Still, the findings do "open up an entirely new treatment
approach to fatal central nervous system tumors--glutamate
therapy," they write in an accompanying editorial.
The editorialists point out that one glutamate blocker,
riluzole, is already approved for treating the fatal
neurological disease amyotrophic lateral sclerosis. And, they
add, it is also worth testing the anti-glioma effects of
several experimental glutamate-blocking drugs that have not
proven effective in clinical trials of stroke patients.
SOURCE: Nature Medicine 2001;7:994-995, 1010-1015.
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