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Author Notes:

Correspondence: Dr RC Castellino, Department of Pediatrics, Emory University School of Medicine, 1760 Haygood Drive NE, HSRB, Room E394, Atlanta, GA 30322, USA. E-mail: rccaste@emory.edu

We thank Drs Jeffrey Benovic, Lawrence Donehower, H Trent Spencer, Laurent Brault, Jürg Schwaller and Rita Nahta for gene expression constructs, Gregory Doho for assistance with analysis of microarrays, and Dr Rita Nahta for editorial assistance.

Dr Castellino’s and Dr Taylor’s work has been funded by the NIH. Other authors declare no conflict of interest.

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.


Research Funding:

This work was supported by grants from the NIH (1R01CA172392–01, RCC; CA159859, MD Taylor), St Baldrick’s Foundation (RCC), CURE Childhood Cancer Foundation (RCC), Southeastern Brain Tumor Foundation (RCC), the Emory Egleston Children’s Research Center (RCC) and the Dr Mildred-Scheel Foundation (MR).

Research reported in this publication was supported in part by the NIH/NCI under award number P30CA138292.


  • Science & Technology
  • Life Sciences & Biomedicine
  • Biochemistry & Molecular Biology
  • Oncology
  • Cell Biology
  • Genetics & Heredity
  • PPM1D

The WIP1 oncogene promotes progression and invasion of aggressive medulloblastoma variants


Journal Title:



Volume 34, Number 9


, Pages 1126-1140

Type of Work:

Article | Post-print: After Peer Review


Recent studies suggest that medulloblastoma, the most common malignant brain tumor of childhood, is comprised of four disease variants. The WIP1 oncogene is overexpressed in Group 3 and 4 tumors, which contain medulloblastomas with the most aggressive clinical behavior. Our data demonstrate increased WIP1 expression in metastatic medulloblastomas, and inferior progression-free and overall survival of patients with WIP1 high-expressing medulloblastoma. Microarray analysis identified upregulation of genes involved in tumor metastasis, including the G protein-coupled receptor CXCR4, in medulloblastoma cells with high WIP1 expression. Stimulation with the CXCR4 ligand SDF1α activated PI-3 kinase signaling, and promoted growth and invasion of WIP1 highexpressing medulloblastoma cells in a p53-dependent manner. When xenografted into the cerebellum of immunodeficient mice, medulloblastoma cells with stable or endogenous high WIP1 expression exhibited strong expression of CXCR4 and activated AKT in primary and invasive tumor cells. WIP1 or CXCR4 knockdown inhibited medulloblastoma growth and invasion. WIP1 knockdown also improved the survival of mice xenografted with WIP1 high-expressing medulloblastoma cells. WIP1 knockdown inhibited cell surface localization of CXCR4 by suppressing expression of the G protein receptor kinase 5, GRK5. Restoration of wild-type GRK5 promoted Ser339 phosphorylation of CXCR4 and inhibited the growth of WIP1-stable medulloblastoma cells. Conversely, GRK5 knockdown inhibited Ser339 phosphorylation of CXCR4, increased cell surface localization of CXCR4 and promoted the growth of medulloblastoma cells with low WIP1 expression. These results demonstrate crosstalk among WIP1, CXCR4 and GRK5, which may be important for the aggressive phenotype of a subclass of medulloblastomas in children.

Copyright information:

© 2015 Macmillan Publishers Limited.

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