Medulloblastoma (MB) is the most common malignant brain tumor in children. MB is thought to arise from progenitor cells in the developing cerebellum that fail to exit the cell division cycle properly, thus providing fertile ground for tumor formation. Many genetic anomalies have been identified in human MB, but only a few have been revealed to be causative. We have genetically engineered two different MB-prone mouse strains that lack the cyclin-D-dependent kinase inhibitor, p18lnk4c, a cell cycle regulatory and tumor suppressor protein whose expression was also revealed to be reduced or absent in human MBs.
In Specific Aim 1, we propose to document the frequency of inactivation of INK4C/CDKN2C in human MBs and to correlate its loss-of-function with other genetic mutations, gene copy number alterations, and gene expression profiles that define different human MB subsets. We will also explore the combined roles of the C-MYC oncoprotein and p53 tumor suppressor in generating a mouse model of large cell anaplastic MBs, the most aggressive and treatment-resistant form of the disease. Many mouse MBs are characterized by mutations affecting a signaling pathway dominated by the mitogen, Sonic Hedgehog (Shh);genetic alterations affecting the Shh signaling pathway have similarly been documented in a subset of human MBs. Our work has established a role for the bone morphogenic proteins (BMPs) in countering Shh signaling, thereby inhibiting proliferation of mouse MBs, and fostering their neuronal differentiation. Not only do BMPs strongly antagonize MB formation in our mouse models, but downregulation of many BMP-responsive genes is a hallmark of Shh-driven human tumors.
In Specific Aim 2, we will study Mathl, a key transcription factor regulated by BMP signaling in an'effort to discern how the activity of this protein is governed, what genes it regulates, and why its role is seemingly essential for MB development. Finally, it is now widely appreciated that small regulatory RNA species (micro-RNAs) globally regulate gene expression and thereby contribute to many forms of cancer.
In Specific Aim 3, we propose methods to characterize in detail the micro-RNAs that contribute to MB formation and tumor maintenance in both mice and humans.

Public Health Relevance

Although many MB patients are cured by combined surgery, radiotherapy and chemotherapy, these aggressive treatments often lead to devastating defects in neurocognitive functions. An improved molecular understanding of those gene products that are instrumental in causing MB should lead to the identification of new druggable targets and to advances in the treatment of this catastrophic tumor of childhood.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Program Projects (P01)
Project #
5P01CA096832-10
Application #
8459551
Study Section
Special Emphasis Panel (ZCA1-GRB-S)
Project Start
Project End
Budget Start
2013-04-01
Budget End
2014-03-31
Support Year
10
Fiscal Year
2013
Total Cost
$253,755
Indirect Cost
$85,370
Name
St. Jude Children's Research Hospital
Department
Type
DUNS #
067717892
City
Memphis
State
TN
Country
United States
Zip Code
38105
Pajtler, Kristian W; Wen, Ji; Sill, Martin et al. (2018) Molecular heterogeneity and CXorf67 alterations in posterior fossa group A (PFA) ependymomas. Acta Neuropathol 136:211-226
Teitz, Tal; Fang, Jie; Goktug, Asli N et al. (2018) CDK2 inhibitors as candidate therapeutics for cisplatin- and noise-induced hearing loss. J Exp Med 215:1187-1203
Tsang, Derek S; Burghen, Elizabeth; Klimo Jr., Paul et al. (2018) Outcomes After Reirradiation for Recurrent Pediatric Intracranial Ependymoma. Int J Radiat Oncol Biol Phys 100:507-515
Shadrick, William R; Slavish, Peter J; Chai, Sergio C et al. (2018) Exploiting a water network to achieve enthalpy-driven, bromodomain-selective BET inhibitors. Bioorg Med Chem 26:25-36
Roussel, Martine F; Stripay, Jennifer L (2018) Epigenetic Drivers in Pediatric Medulloblastoma. Cerebellum 17:28-36
Waszak, Sebastian M; Northcott, Paul A; Buchhalter, Ivo et al. (2018) Spectrum and prevalence of genetic predisposition in medulloblastoma: a retrospective genetic study and prospective validation in a clinical trial cohort. Lancet Oncol 19:785-798
El Nagar, Salsabiel; Zindy, Frederique; Moens, Charlotte et al. (2018) A new genetically engineered mouse model of choroid plexus carcinoma. Biochem Biophys Res Commun 496:568-574
Nimmervoll, Birgit V; Boulos, Nidal; Bianski, Brandon et al. (2018) Establishing a Preclinical Multidisciplinary Board for Brain Tumors. Clin Cancer Res 24:1654-1666
Vo, BaoHan T; Kwon, Jin Ah; Li, Chunliang et al. (2018) Mouse medulloblastoma driven by CRISPR activation of cellular Myc. Sci Rep 8:8733
Wei, Lei; Murphy, Brian L; Wu, Gang et al. (2017) Exome sequencing analysis of murine medulloblastoma models identifies WDR11 as a potential tumor suppressor in Group 3 tumors. Oncotarget 8:64685-64697

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