This Project pursues recent advances in the cell biology of medulloblastomas (MBs) and related central nervous system (CNS) primitive neuroectodermal tumors (PNETs) by studying neurotrophins and their cognate receptors (trkA, trkB or trkC) to gain insights into the role of neurotrophins in the progression of these common pediatric brain tumors. MB cells resemble immature CNS neurons or their progenitors, and MBs primarily occur in the first decade of life when heterotopic immature neurons and/or neuroectodermal progenitor cells are most abundant in cerebellum where most MBs arise. The relevant CNS neurotrophins that might regulate the behavior of neuroectodermal progenitors as well as MBs and PNETs are nerve growth factor (NGF) and related neurotrophins, i.e. brain derived neurotrophic factor (BDNF), NT3 and NT4/5. These factors bind to the low affinity NGF receptor (LNGFR), but the effects of NGF, BDNF NT3 and NT4/5 are thought to be mediated primarily by high affinity receptors, i.e.. trkA (NGF, NT4/5), trkB (BDNF, NT4/5) or trkC (NT3). Studies from our laboratory indicate that trk receptor proteins are expressed in the developing and mature human cerebellum, and that MBs, PNETs and cell lines derived therefrom express trk proteins. Thus, we hypothesize that MBs arise from the failure of neuroectodermal progenitors to respond to endogenous neurotrophins. Instead of undergoing normal cell death or completing a normal program of neuronal differentiation, these progenitors may persist in the immature postnatal brain and sustain genetic mutations that result in MBs and related PNETs. Accordingly, this Project will investigate these issues by identifying the neurotrophin receptor/neurotrophin signaling pathways that may be involved in the emergence and progression of human MBs and related PNETs of the CNS.

Project Start
1998-05-01
Project End
1999-04-30
Budget Start
1997-10-01
Budget End
1998-09-30
Support Year
3
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Children's Hospital of Philadelphia
Department
Type
DUNS #
073757627
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Ho, Ruth; Eggert, Angelika; Hishiki, Tomoro et al. (2002) Resistance to chemotherapy mediated by TrkB in neuroblastomas. Cancer Res 62:6462-6
Eggert, A; Grotzer, M A; Zuzak, T J et al. (2002) Expression of Apo-3 and Apo-3L in primitive neuroectodermal tumours of the central and peripheral nervous system. Eur J Cancer 38:92-8
Tang, X X; Evans, A E; Zhao, H et al. (2001) Association among EPHB2, TrkA, and MYCN expression in low-stage neuroblastomas. Med Pediatr Oncol 36:80-2
Eggert, A; Grotzer, M A; Zuzak, T J et al. (2001) Resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in neuroblastoma cells correlates with a loss of caspase-8 expression. Cancer Res 61:1314-9
Grotzer, M A; Wiewrodt, R; Janss, A J et al. (2001) High microvessel density in primitive neuroectodermal brain tumors of childhood. Neuropediatrics 32:75-9
Grotzer, M A; Janss, A J; Fung, K M et al. (2001) Abundance of apoptotic neoplastic cells in diagnostic biopsy samples is not a prognostic factor in childhood primitive neuroectodermal tumors of the central nervous system. J Pediatr Hematol Oncol 23:25-9
Grotzer, M A; Geoerger, B; Janss, A J et al. (2001) Prognostic significance of Ki-67 (MIB-1) proliferation index in childhood primitive neuroectodermal tumors of the central nervous system. Med Pediatr Oncol 36:268-73
Geoerger, B; Kerr, K; Tang, C B et al. (2001) Antitumor activity of the rapamycin analog CCI-779 in human primitive neuroectodermal tumor/medulloblastoma models as single agent and in combination chemotherapy. Cancer Res 61:1527-32
Evans, A E; Kisselbach, K D; Liu, X et al. (2001) Effect of CEP-751 (KT-6587) on neuroblastoma xenografts expressing TrkB. Med Pediatr Oncol 36:181-4
Eggert, A; Grotzer, M A; Ikegaki, N et al. (2001) Expression of the neurotrophin receptor TrkB is associated with unfavorable outcome in Wilms' tumor. J Clin Oncol 19:689-96

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