Robert Wechsler-Reya, Ph.D.[La Jolla]
Medulloblastoma and astrocytoma are the most common brain tumors in children. By examining the role stem cells play in the development of these tumors, we will deepen our understanding of how brain tumors form and can develop novel approaches to treating them.
Dr. Wechsler-Reya’s group studies the signals that control cell growth and differentiation in the nervous system.
Dr. Wechsler-Reya received his Ph.D., University of Pennsylvania, Immunology, 1995.
Identification of CD15 as a marker for tumor-propagating cells in a mouse model of medulloblastoma.
Read TA, Fogarty MP, Markant SL, McLendon RE, Wei Z, Ellison DW, Febbo PG, Wechsler-Reya RJ
Cancer Cell. 2009 Feb 3;15(2):135-47
N-myc alters the fate of preneoplastic cells in a mouse model of medulloblastoma.
Kessler JD, Hasegawa H, Brun SN, Emmenegger BA, Yang ZJ, Dutton JW, Wang F, Wechsler-Reya RJ
Genes Dev. 2009 Jan 15;23(2):157-70
Stem cells and the origin and propagation of brain tumors.
Emmenegger BA, Wechsler-Reya RJ
J Child Neurol. 2008 Oct;23(10):1172-8
Medulloblastoma can be initiated by deletion of Patched in lineage-restricted progenitors or stem cells.
Yang ZJ, Ellis T, Markant SL, Read TA, Kessler JD, Bourboulas M, Schüller U, Machold R, Fishell G, Rowitch DH, Wainwright BJ, Wechsler-Reya RJ
Cancer Cell. 2008 Aug 12;14(2):135-45
Fibroblast growth factor blocks Sonic hedgehog signaling in neuronal precursors and tumor cells.
Fogarty MP, Emmenegger BA, Grasfeder LL, Oliver TG, Wechsler-Reya RJ
Proc Natl Acad Sci U S A. 2007 Feb 20;104(8):2973-8
Hit 'em where they live: targeting the cancer stem cell niche.
Yang ZJ, Wechsler-Reya RJ
Cancer Cell. 2007 Jan;11(1):3-5
The neurobiology of neurooncology.
Read TA, Hegedus B, Wechsler-Reya R, Gutmann DH
Ann Neurol. 2006 Jul;60(1):3-11
Morphing into cancer: the role of developmental signaling pathways in brain tumor formation.
Fogarty MP, Kessler JD, Wechsler-Reya RJ
J Neurobiol. 2005 Sep 15;64(4):458-75
Isolation of neural stem cells from the postnatal cerebellum.
Lee A, Kessler JD, Read TA, Kaiser C, Corbeil D, Huttner WB, Johnson JE, Wechsler-Reya RJ
Nat Neurosci. 2005 Jun;8(6):723-9
Loss of patched and disruption of granule cell development in a pre-neoplastic stage of medulloblastoma.
Oliver TG, Read TA, Kessler JD, Mehmeti A, Wells JF, Huynh TT, Lin SM, Wechsler-Reya RJ
Development. 2005 May;132(10):2425-39
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Differential immune microenvironments and response to immune checkpoint blockade amongst molecular subtypes of murine medulloblastoma.
Pham CD, Flores C, Yang C, Pinheiro EM, Yearley JH, Sayour E, Pei Y, Moore C, McLendon RE, Huang J, Sampson JH, Wechsler-Reya RJ, Mitchell DA
Clin Cancer Res. 2015 Sep 24;
Robert Wechsler-Reya's Research Focus
Brain Cancer, Childhood Diseases
Normal development requires a delicate balance between proliferation, differentiation, and death. When these processes become dysregulated, a cell that would normally differentiate or die may divide uncontrollably, and a tumor may result. Dr. Wechsler-Reya’s research focuses on the molecular mechanisms that regulate cell growth and tumorigenesis in the nervous system. In particular, his group studies the role of the Sonic hedgehog (Shh) signaling pathway in the development of the cerebellum and in the genesis of a brain tumor called medulloblastoma.
Robert Wechsler-Reya's Research Report
Control of Neuronal Growth and Differentiation
Proper development of the nervous system requires a balance between proliferation of neuronal precursors and differentiation of these cells into neurons. This balance is particularly striking in the case of cerebellar granule cells, the most abundant neurons in the brain and a critical component of the circuitry that controls motor coordination. When granule cell precursor proliferation is disrupted and not enough granule cells are generated, cerebellar dysfunction and ataxia may result; when granule cell differentiation fails, cells that would normally become post-mitotic continue to proliferate and may give rise to cerebellar tumors. Therefore, elucidating the molecular mechanisms that control growth and differentiation is critical for understanding both normal cerebellar development and tumorigenesis.
Our previous studies demonstrated that proliferation of granule neuron precursors (GNPs) is controlled by the secreted signaling molecule Sonic hedgehog (Shh). But the signals that cause GNPs to stop proliferating, differentiate and migrate remain a mystery. Using both primary cell culture and transgenic mouse models, we are investigating the role of fibroblast growth factors, netrins, chemokines and other signals in granule cell development.
Brain Tumor Initiation and Progression
Medulloblastoma is the most common malignant brain tumor in children. Its rapid growth and tendency to spread through the nervous system make it difficult to treat, and many of the children who develop the disease die from it. In addition, patients who survive medulloblastoma treatment often suffer cognitive deficits and have a tendency to develop other cancers later in life. Improved treatment of medulloblastoma is likely to come from a deeper understanding of the signals that control normal cerebellar development, and an appreciation of how these signals are dysregulated in tumors.
To identify such signals, we have studied an animal model of medulloblastoma -- the
patched mutant mouse -- and screened for genes whose expression is altered in tumor cells compared to granule cell precursors, the cells from which the tumor is believed to arise. The genes whose expression changed most significantly included regulators of migration, apoptosis and differentiation, processes crucial for normal development but previously unrecognized for their role in medulloblastoma. Current studies in our lab are using retroviral gene transduction, cell transplantation and transgenic mice to elucidate the role of these genes in tumor initiation and progression.
Stem Cells and the Origin of Brain Tumors
Stem cells are likely to play a central role in cancer. Their long lifespan and extensive capacity for self-renewal make them particularly sensitive to transformation, so they may represent a cell of origin for many tumors. A number of recent studies have suggested that stem-like cells are present in human brain tumors, but the role of stem cells in brain tumor initiation has not been tested. Studies in our lab are aimed at examining the role of neural stem cells in the etiology of the cerebellar tumor medulloblastoma.
Recent studies from our lab have identified a population of neural stem cells in the postnatal cerebellum. These cells express the stem cell marker CD133, can form self-renewing "neurospheres" in culture, and can be induced to differentiate into neurons, astrocytes and oligodendrocytes both in vitro and following transplantation into the cerebellum. Our current research is directed at understanding the role of these cells in normal cerebellar development, and exploring the possibility that they might represent the cell of origin for some types of medulloblastoma.
About Robert Wechsler-Reya
Dr. Wechsler-Reya's research focuses on the signals that control growth and differentiation in the cerebellum, and how these signals are dysregulated in the brain tumor medulloblastoma. As a postdoc, he demonstrated that Sonic hedgehog (Shh) is a critical mitogen for neuronal precursors in the cerebellum, and that mutations in the Shh pathway predispose to medulloblastoma by activating a mitogenic pathway that normally functions only in early development. Now in his own lab, he continues to study the relationship between brain development and brain tumor formation. His lab’s contributions include identifying N-myc as a key target of the Shh pathway in neuronal precursors and in tumor cells; discovering a novel population of neural stem cells in the neonatal cerebellum; demonstrating that both neuronal precursors and stem cells can serve as cells of origin for MB; and identifying a population of cancer stem cells that is critical for propagation of Shh-associated tumors. More recently, Dr. Wechsler-Reya and his group have begun developing new models of medulloblastoma and are using them to test novel therapeutic approaches. His work has garnered several awards, including a Kimmel Scholar Award, an Award for Excellence in Pediatrics Research from the Society for Neuro-Oncology and a Leadership Award from the California Institute for Regenerative Medicine (CIRM).
Associate Professor of Pharmacology and Cancer Biology, Duke University Medical Center, 2001–2010
Postdoctoral Fellow, Stanford University, Neural Development, 1997-2001
Postdoctoral Fellow, Wistar Institute, Molecular Oncology, 1995-1996
Ph.D., University of Pennsylvania, Immunology, 1995
B.A., Harvard College, Psychology & Biology, 1986
Funding Awards and Collaborative Grants
Leadership Award from the California Institute for Regenerative Medicine (CIRM)
Honors and Recognition
W.K. Joklik Award for Excellence in Basic Cancer Research, 2007
DukeMed Scholar, 2007
Award for Excellence in Pediatrics Research, Society for Neuro-Oncology, 2006
Kimmel Scholar Award, Sidney Kimmel Foundation for Cancer Research, 2003
Brain Tumor Society Research Award, 2003
Children’s Brain Tumor Foundation Research Award, 2002
Postdoctoral Fellowship, American Cancer Society (California), 2000–2001
Postdoctoral Fellowship, Medical Research Council of Canada, 1995–1997
Award for Excellence in Scientific Writing, American Diabetes Association, 1988
John Harvard Scholarship for Academic Achievement of Highest Distinction, 1984–1985
June 21 – 24, 2012
19th International Brain Tumor Research and Therapy Conference
A University of Toronto Hosted Conference
Niagara Falls, ON
"Developmental tumors of the nervous system", to be held in Barcelona on July 2012, as part of the 8th Forum of European Neuroscience Societies.