Led by Jeremy Rich, M.D., associate professor at the Preston Robert Tisch Brain Tumor Center at Duke University, the researchers found that a small subset of glioma cells expressed higher levels of a growth factor associated with cancer cell growth. They believe this subset could be a target for new therapies against these intractable brain tumors.
Gliomas are the most common type of brain tumor, making up about half of all diagnosed primary (or non-metastatic) brain tumors. About 17,000 people in the United States are diagnosed with a primary brain tumor each year. Patients with the most aggressive glioma, called glioblastoma, have an average life expectancy of less than one year despite advances in cancer treatment. To better treat cancer patients, laboratories like those of Rich are trying to better understand the causes of tumor growth so that gliomas can be targeted with new drugs.
"Malignant brain tumors are highly lethal, despite aggressive surgery, radiation, and chemotherapy," said Dr. Rich. "We believe targeting the cancer stem cells of brain tumors may offer a novel therapy that will help to decrease the blood supply feeding a growing tumor, and therefore decrease or stop that tumor's growth."
Researchers from other laboratories recently determined that a small fraction of all the cells in a glioma have special characteristics similar to brain stem cells. These stem cell-like glioma cells form tumors when implanted in animals. As the ability to form new blood vessels (called angiogenesis) to supply blood carrying nutrients is critical in cancer growth, Dr. Rich's team studied if the formation of tumors by stem cell-like glioma cells could be due to increased angiogenesis. Angiogenesis is often stimulated by a key growth factor called VEGF. Rich and colleagues found that stem cell-like glioma cells enhanced the angiogenesis of gliomas through increased levels of VEGF.
Using an antibody to mark the cancer stem cells in gliomas obtained from patient specimens, the Rich laboratory determined that between three-to-five percent of tumor cells were of the stem cell-like variety. They found that these stem cell-like glioma cancer cells expressed much higher levels of VEGF and formed more tumors with more blood vessels than glioma cells that did not have stem cell characteristics. Adding an antibody (bevacizumab, also known by the trade name Avastin) that blocks VEGF activity blocked new blood vessel formation and prevented tumor growth. The researchers suggest that the stem cell-like glioma cells, because of their support of angiogenesis, could hold an important target to suppressing the growth of brain cancer.
"VEGF antibodies may be effective as cancer therapies when combined with chemotherapy by improving delivery directly and specifically to stem cell-like tumor cells," said Dr. Rich. "Targeting VEGF in this way would not kill cancer cells directly, but instead would block the actions of adjacent cells that support the growth of their blood supply."
Dr. Rich's lab studies the complex relationships between cell signaling pathways and the development of cancer, especially in the nervous system. The lab is investigating a number of molecular targets that contribute to cancer growth and malignancy.
"Too often, brain tumor patients have been told there is no hope. Our overall objective is to give brain tumor patients that hope, while we do not expect to achieve instant victories in the near future," said Dr. Rich.
Warren Froelich | EurekAlert!
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The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
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The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
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Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
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The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
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