Skip to comments.Brain's Stem Cells Hold Clues to Cancer
Posted on 07/23/2006 11:33:14 AM PDT by neverdem
THURSDAY, July 20 (HealthDay News) -- Researchers say they're gaining greater insight into how the brain's own stem cells may trigger one of the deadliest forms of cancer.
The stem cells -- which can turn into a variety of brain cells -- appear to carry a receptor that pulls in a specific chemical. If the cells get over-stimulated by the chemical, that may lead to tumor formation.
The discovery, "might lead to better understanding of early growth" of brain malignancies, said study co-author Arturo Alvarez-Buylla, a professor of neurological surgery at the University of California, San Francisco. As a result, he said, "We might be able to make some headway in diagnosing cases early," when they are most receptive to treatment.
At issue are brain tumors called malignant gliomas. Brain tumors are routinely fatal, but malignant gliomas are especially deadly because they're often not discovered until they've grown significantly, sometimes becoming as large as a fist, Alvarez-Buylla said.
Other factors conspire to make malignant gliomas incurable in adults for "all practical purposes," said Charles D. Stiles, a professor of microbiology and molecular genetics at Harvard Medical School. The tumors are hard to find, are often in areas of the brain that surgeons can't reach, and are "notoriously resistant to radiation therapy," Stiles said.
In the new study, which received partial funding from the federal government, Alvarez-Buylla and colleagues examined non-embryonic, neural stem cells called "B cells" in mice and tried to determine how they function.
Reporting in the July 20 issue of Neuron, the researchers found that B cells in mice and humans have a receptor for a chemical called platelet-derived growth factor.
When the cells are "stimulated" with the chemical in mice, they began to grow tumor-like masses, Alvarez-Buylla said. On the other hand, when this growth factor is removed, "the cells stop growing and the tissue recovers."
The research suggests that the growth factor can trigger the cells in humans to "grow in a very abnormal manner and invade the tissue around them," Alvarez-Buylla said.
What's next? More research could give scientists a greater understanding of the brain cancer process, Alvarez-Buylla said.
But, for now, the research has no direct impact on the treatment of glioma patients, said Stiles, who co-wrote a commentary accompanying the study. Indeed, he said, one clinical trial has already shown that inhibiting the growth factor won't help patients with recurrent tumors.
Even so, Stiles said, the "line of attack" suggested in the study should be "reexamined and pursued."
Learn more about brain malignancies at the American Cancer Society.
Neural stem cells in the mammalian brain persist and are functional well into adulthood. There is, however, little insight into mechanisms that control adult neural stem cell survival. Mice deficient in the proapoptotic molecule Bax exhibit increased numbers of multipotent progenitor cells in the adult subventricular zone. In vitro, these progenitors behave as neural stem cells and utilize Bax and caspase activation to direct cell death. We demonstrate that the predominate mechanism underlying caspase and Bax-mediated adult neural stem cell death lies in the modulation of calcium flux through interaction with the IP3 receptor.
Oops - the Bush Administration is supporting stem cell research? Wait - it's Forbes, so I guess the truth will be reported.
Thanks for the ping.
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