101
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Wolfe KR, Madan-Swain A, Kana RK. Executive dysfunction in pediatric posterior fossa tumor survivors: a systematic literature review of neurocognitive deficits and interventions. Dev Neuropsychol 2012; 37:153-75. [PMID: 22339228 DOI: 10.1080/87565641.2011.632462] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Improved medical therapies have increased survivorship rates for children with posterior fossa tumors; resultantly, morbidities associated with survivorship, such as executive function deficits, have become increasingly important to identify and address. Executive dysfunction can impact academic achievement as well as functional outcomes. We summarize studies describing executive functioning deficits in pediatric posterior fossa tumor survivors who received cranial radiation therapy and intervention studies that have targeted executive functioning deficits. Previous theoretical models describing the etiology of these deficits are reviewed, and a new, more comprehensive model is proposed. Future research should move toward incorporating neuroimaging, longitudinal designs, and multiple informants.
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Affiliation(s)
- Kelly R Wolfe
- Department of Psychology, University of Alabama, Birmingham, USA.
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102
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Smits M, van Rijn S, Hulleman E, Biesmans D, van Vuurden DG, Kool M, Haberler C, Aronica E, Vandertop WP, Noske DP, Würdinger T. EZH2-regulated DAB2IP is a medulloblastoma tumor suppressor and a positive marker for survival. Clin Cancer Res 2012; 18:4048-58. [PMID: 22696229 DOI: 10.1158/1078-0432.ccr-12-0399] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE Medulloblastoma is the most common malignant brain tumor in children. Despite recent improvements, the molecular mechanisms driving medulloblastoma are not fully understood and further elucidation could provide cues to improve outcome prediction and therapeutic approaches. EXPERIMENTAL DESIGN Here, we conducted a meta-analysis of mouse and human medulloblastoma gene expression data sets, to identify potential medulloblastoma tumor suppressor genes. RESULTS We identified DAB2IP, a member of the RAS-GTPase-activating protein family (RAS GAP), and showed that DAB2IP expression is repressed in medulloblastoma by EZH2-induced trimethylation. Moreover, we observed that reduced DAB2IP expression correlates significantly with a poor overall survival of patients with medulloblastoma, independent of metastatic stage. Finally, we showed that ectopic DAB2IP expression enhances stress-induced apoptosis in medulloblastoma cells and that reduced expression of DAB2IP in medulloblastoma cells conveys resistance to irradiation-induced cell death. CONCLUSION These results suggest that repression of DAB2IP may at least partly protect medulloblastoma cells from apoptotic cell death. Moreover, DAB2IP may represent a molecular marker to distinguish patients with medulloblastoma at high risk from those with a longer survival prognosis.
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Affiliation(s)
- Michiel Smits
- Neuro-oncology Research Group, Department of Neurosurgery, Cancer Center Amsterdam, VU University Medical Center, Amsterdam, The Netherlands
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103
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Nageswara Rao AA, Packer RJ. Impact of molecular biology studies on the understanding of brain tumors in childhood. Curr Oncol Rep 2012; 14:206-12. [PMID: 22237928 DOI: 10.1007/s11912-012-0214-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Pediatric brain tumors are the second most common form of childhood malignancy. Brain tumors are a very heterogenous group of tumors and the pathogenesis of many of these tumors is yet to be clearly elucidated. Current diagnostic tools include histopathology and immunohistochemistry, but classification based on these means has significant limitations. As our understanding of the molecular biology of individual tumors continues to increase it has led to the identification of reliable and increasingly available molecular biomarkers. Molecular techniques are likely to complement current standard means of investigation and help not only overcome diagnostic challenges but may also result in better disease classification and risk stratification, leading to more personalized therapeutic approaches.
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Affiliation(s)
- Amulya A Nageswara Rao
- Division of Pediatric Hematology/Oncology, Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, MN 55905, USA.
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104
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Markant SL, Wechsler-Reya RJ. Personalized mice: modelling the molecular heterogeneity of medulloblastoma. Neuropathol Appl Neurobiol 2012; 38:228-40. [DOI: 10.1111/j.1365-2990.2011.01235.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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105
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Abstract
Stem cells of normal mammalian tissues are defined as nonspecialized cells that have two critical properties: (a) the ability to renew themselves through cell division and (b) the potency to differentiate into other cell types. Therefore, they play a crucial role in development and in tissue homeostasis during adult life. Being long-lived, they can be the targets of environmental carcinogens leading to the accumulation of consecutive genetic changes. Hence, the genome of stem cells must be exceptionally well protected, and several protective mechanisms have evolved to ensure the genetic integrity of the stem cell compartment in any given tissue. Ionizing radiation exposure can disrupt tissue homeostasis both through the induction of cell killing/depletion of radiosensitive stem cells, leading to loss of tissue functionality and by genotoxic damage, increasing overall risk of cancer. We will review the current knowledge about radiation effects in adult stem cells of specific normal tissues, including skin, breast, and brain, examine parallels, as well as differences with cancer stem cells, and discuss the relevance of stem cell effects to radiation risk and radiotherapy.
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Affiliation(s)
- Kevin M Prise
- Centre for Cancer Research & Cell Biology, Queen's University Belfast, Belfast, United Kingdom.
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106
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Cage TA, Louie JD, Liu SR, Alvarez-Buylla A, Gupta N, Hyer J. Distinct patterns of human medulloblastoma dissemination in the developing chick embryo nervous system. Clin Exp Metastasis 2012; 29:371-80. [PMID: 22322278 DOI: 10.1007/s10585-012-9456-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 01/21/2012] [Indexed: 11/29/2022]
Abstract
Medulloblastoma (MB) is the most common malignant primary brain tumor in children. Aggressive tumors that disseminate along the leptomeninges carry extremely poor prognoses. Mechanisms that predict dissemination are poorly understood. Our objective was to develop a reliable and reproducible model to study MB dissemination. We have created a chicken-human xenograft to study features of MB with leptomeningeal dissemination. Human MB cell lines (D283, Daoy), primary human MB cells (SF8113), and primary genetic mouse model (Math1cre:SmoM2 flox/flox) MB cells were either transfected to express green fluorescent protein (GFP) or were labeled with a membrane permeable green fluorescent probe. Cells were then injected as aggregates or implanted as pellets into the developing chicken brain immediately after neural tube closure at embryonic day 2 (E2). Most embryos were harvested three days after implantation (E5) though some were harvested up to E15. The developing brain was analyzed via whole mount fluorescent imaging and tissue section immunohistochemistry. Human and mouse MBs survived in the developing chicken central nervous system (CNS). They exhibited distinct patterns of incorporation and dissemination into the CNS that were consistent with observed phenotypes of the corresponding human patient or mouse host. Specifically, metastatic D283 cells disseminated along the leptomeninges whereas Daoy, primary mouse MB, and primary human MB cells did not. This work supports an avian-human xenograft as a successful model to study patterns of MB dissemination. Our model provides a basis for manipulating cell signaling mechanisms to understand critical targets involved in MB dissemination.
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Affiliation(s)
- Tene A Cage
- Department of Neurological Surgery, University of California, San Francisco, 513 Parnassus Ave, San Francisco, CA 94143-0112, USA
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107
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FISH and chips: the recipe for improved prognostication and outcomes for children with medulloblastoma. Cancer Genet 2012; 204:577-88. [PMID: 22200083 DOI: 10.1016/j.cancergen.2011.11.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 11/03/2011] [Accepted: 11/07/2011] [Indexed: 11/20/2022]
Abstract
Rapidly evolving genomic technologies have permitted progressively detailed studies of medulloblastoma biology in recent years. These data have increased our understanding of the molecular pathogenesis of medulloblastoma, identified prognostic markers, and suggested future avenues for targeted therapy. Although current randomized trials are still stratified based largely on clinical variables, the use of molecular markers is approaching routine use in the clinic. In particular, integrated genomics has uncovered that medulloblastoma comprises four distinct molecular and clinical variants: WNT, sonic hedgehog (SHH), group 3, and group 4. Children with WNT medulloblastoma have improved survival, whereas those with group 3 medulloblastoma have a dismal prognosis. Additionally, integrated genomics has shown that adult medulloblastoma is molecularly and clinically distinct from the childhood variants. Prognostic and predictive markers identified by genomics should drive changes in stratification of treatment protocols for medulloblastoma patients on clinical trials once they can be demonstrated to be reliable, reproducible, and practical. Cases with excellent prognoses (WNT cases) should be considered for therapy de-escalation, whereas those with bleak prognoses (group 3 cases) should be prioritized for experimental therapy. In this review, we will summarize the genomic data published over the past decade and attempt to interpret its prognostic significance, relevance to the clinic, and use in upcoming clinical trials.
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108
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GU C, YOKOTA N, GAO Y, AMANO S, KOIZUMI S, TOKUYAMA T, NAMBA H. Molecular Targeting Therapy Against Promyelocytic Leukemia Protein Using Arsenic Acids in Experimental Intracranial Medulloblastoma. Neurol Med Chir (Tokyo) 2012; 52:62-7. [DOI: 10.2176/nmc.52.62] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Chunyu GU
- Department of Neurosurgery, Hamamatsu University School of Medicine
- Department of Neurosurgery, Shengjing Hospital of China Medical University
| | - Naoki YOKOTA
- Department of Neurosurgery, Hamamatsu University School of Medicine
- Yokohama CyberKife Center
| | - Yun GAO
- Department of Neurosurgery, Hamamatsu University School of Medicine
| | - Shinji AMANO
- Department of Neurosurgery, Hamamatsu University School of Medicine
| | | | - Tsutomu TOKUYAMA
- Department of Neurosurgery, Hamamatsu University School of Medicine
| | - Hiroki NAMBA
- Department of Neurosurgery, Hamamatsu University School of Medicine
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109
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Stockhausen MT, Kristoffersen K, Poulsen HS. Notch signaling and brain tumors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 727:289-304. [PMID: 22399356 DOI: 10.1007/978-1-4614-0899-4_22] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Human brain tumors are a heterogenous group of neoplasms occurring inside the cranium and the central spinal cord. In adults and children, astrocytic glioma and medulloblastoma are the most common subtypes of primary brain tumors. These tumor types are thought to arise from cells in which Notch signaling plays a fundamental role during development. Recent findings have shown that Notch signaling is dysregulated and contributes to the malignant potential of these tumors. Growing evidence point towards an important role for cancer stem cells in the initiation and maintenance of glioma and medulloblastoma. In this chapter we will cover the present findings of Notch signaling in human glioma and medulloblastoma and try to create an overall picture of its relevance in the pathogenesis of these tumors.
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110
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Guessous F, Yang Y, Johnson E, Marcinkiewicz L, Smith M, Zhang Y, Kofman A, Schiff D, Christensen J, Abounader R. Cooperation between c-Met and focal adhesion kinase family members in medulloblastoma and implications for therapy. Mol Cancer Ther 2011; 11:288-97. [PMID: 22188814 DOI: 10.1158/1535-7163.mct-11-0490] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We previously showed the involvement of the tyrosine kinase receptor c-Met in medulloblastoma malignancy. The nonreceptor tyrosine kinases focal adhesion kinase (FAK) and Pyk2 are key players in the progression of different cancers. However, their role in medulloblastoma malignancy is not well understood. In this study, using a protein array approach, we found that c-Met induces FAK and Pyk2 phosphorylation in medulloblastoma cells. We therefore studied the interactions between c-Met and FAK/Pyk2 and their implications for medulloblastoma therapy. We found that c-Met activates FAK and Pyk2 in several medulloblastoma cell lines. We also found that FAK and Pyk2 mediate the malignant effects of c-Met on medulloblastoma cell proliferation, migration, and invasion. On the basis of these findings, we hypothesized that combined c-Met and FAK inhibitions would have additive effects on the inhibition of medulloblastoma malignancy. To test this hypothesis, we assessed the effects on medulloblastoma malignancy parameters of single or combined treatments of medulloblastoma cells with c-Met and FAK small-molecule kinase inhibitors. We found a significant increase in the inhibitory effect of both inhibitors on medulloblastoma cell migration and cell invasion as compared with single inhibitions (P < 0.05). In addition, oral gavage treatment with c-Met inhibitor of mice bearing medulloblastoma xenografts significantly reduced in vivo tumor growth. Therefore, combining c-Met inhibitors with FAK inhibitors constitutes a new potential strategy for medulloblastoma therapy. Altogether, our study describes a role for FAK and Pyk2 in medulloblastoma malignancy, uncovers new interactions between c-Met and FAK/Pyk2, and proposes for the first time combining anti-c-Met and anti-FAK inhibitors as a new strategy for medulloblastoma therapy.
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Affiliation(s)
- Fadila Guessous
- Department of Microbiology, University of Virginia, Charlottesville, VA 22908, USA
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111
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Appraisal of the current staging system for residual medulloblastoma by volumetric analysis. Childs Nerv Syst 2011; 27:2101-6. [PMID: 21814819 DOI: 10.1007/s00381-011-1533-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2011] [Accepted: 07/12/2011] [Indexed: 10/17/2022]
Abstract
AIM This study aims to investigate the accuracy of the current staging system of childhood medulloblastoma by using volumetric image analysis on immediate post-operative MRI scans. MATERIAL AND METHODS Tumour volume and maximum cross area of residual medulloblastoma were measured on immediate post-operative MR scans of 37 children operated between 1999 and 2005. RESULTS Mean preoperative volume was 32 cm(3) (range 4.5-71.9 cm(3)). Mean post-operative volume was 3.3 cm(3) (range 0-23.3 cm(3)). At mean follow-up of 50.08 months (range 6-129), 15 (40%) patients had died. Cut-off limit for residual post-operative tumour volume employed was maximum cross section of 1.5 cm(2), which corresponds to volume of 1.376 cm(3); 14 patients (38%) had no residual tumour, 7 patients (19%) had less than 1.5 cm(2) and 16 patients (43%) had more than 1.5 cm(2) residual tumour in its maximum cross section area. In three patients (8.2%) there was mismatch between the measured maximum cross section area and volume. In particular, in two patients, the cross section areas were more than 1.5 cm(2) but the residual tumour volumes were less than 1.376 cm(3) (the cross section area overestimated the residual volume) and in one case, the cross section area was less than 1.5 cm(2) but the residual tumour volume was more than 1.376 cm(3) (the cross section area underestimated the residual volume; difference statistically significant, Fisher's exact test, p < 0.01). CONCLUSIONS It appears that volumetric measurement of residual medulloblastoma on immediate post-operative MRI scans may further improve the accuracy of staging process.
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112
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Park AK, Lee SJ, Phi JH, Wang KC, Kim DG, Cho BK, Haberler C, Fattet S, Dufour C, Puget S, Sainte-Rose C, Bourdeaut F, Grill J, Delattre O, Kim SK, Park WY. Prognostic classification of pediatric medulloblastoma based on chromosome 17p loss, expression of MYCC and MYCN, and Wnt pathway activation. Neuro Oncol 2011; 14:203-14. [PMID: 22090452 DOI: 10.1093/neuonc/nor196] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pediatric medulloblastoma is considered a highly heterogeneous disease and a new strategy of risk stratification to optimize therapeutic outcomes is required. We aimed to investigate a new risk-stratification approach based on expression profiles of medulloblastoma cohorts. We analyzed gene expression profiles of 30 primary medulloblastomas and detected strong evidence that poor survival outcome was significantly associated with mRNA expression profiles of 17p loss. However, it was not supported in independent cohorts from previously published data (n = 100). We speculated that this discrepancy might come from complex conditions of two important prognostic determinants: loss of tumor suppressors (chromosome 17p) and high expression of oncogenes c-myc (MYCC) or N-myc (MYCN). When patients were stratified into 5 or 7 subgroups based on simultaneous consideration of these 2 factors while defining the Wnt group as independent, obviously different survival expectancies were detected between the subgroups. For instance, predicted 5-year survival probabilities ranged from 19% to 81% in the 5 subgroups. We also found that age became a significant prognostic marker after adjusting for 17p, MYCC, and MYCN status. Diminished survival in age <3 years was more substantial in subgroups with high expression of MYCC, MYCN, or 17p loss but not in other subgroups, indicating that poor survival outcome might be synergistically affected by these 3 factors. Here we suggest a more tailored subgrouping system based on expression profiles of chromosome 17p, MYCC, and MYCN, which could provide the basis for a novel risk-stratification strategy in pediatric medulloblastoma.
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Affiliation(s)
- Ae Kyung Park
- College of Pharmacy, Sunchon National University, Korea
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113
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Grunder E, D'Ambrosio R, Fiaschetti G, Abela L, Arcaro A, Zuzak T, Ohgaki H, Lv SQ, Shalaby T, Grotzer M. MicroRNA-21 suppression impedes medulloblastoma cell migration. Eur J Cancer 2011; 47:2479-90. [PMID: 21775132 DOI: 10.1016/j.ejca.2011.06.041] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 06/07/2011] [Accepted: 06/17/2011] [Indexed: 12/19/2022]
Abstract
Medulloblastoma (MB), the most common malignant brain tumour in children, is characterised by a high risk of leptomeningeal dissemination. But little is known about the molecular mechanisms that promote cancer cell migration in MB. Aberrant expression of miR-21 is recognised to be causatively linked to metastasis in a variety of human neoplasms including brain tumours; however its function in MB is still unknown. In this study we investigated the expression level and the role of miR-21 in MB cell migration. miR-21 was found to be up-regulated, compared to normal cerebellum, in 29/29 MB primary samples and 6/6 MB-derived cell lines. Inverse correlation was observed between miR-21 expression and the metastasis suppressor PDCD4, while miR-21 repression increased the release of PDCD4 protein, suggesting negative regulation of PDCD4 by miR-21 in MB cells. Anti-miR-21 decreased protein expression of the tumour cell invasion mediators MAP4K1 and JNK, which are also known to be negatively regulated by PDCD4, and down-regulated integrin protein that is essential for MB leptomeningeal dissemination. Moreover miR-21 knockdown in MB cells increased the expression of two eminent negative modulators of cancer cell migration, E-Cadherin and TIMP2 proteins that are known to be positively regulated by PDCD4. Finally and importantly, suppression of miR-21 decreased the motility of MB cells and reduced their migration across basement membranes in vitro. Together, these compelling data propose miR-21 pathway as a novel mechanism impacting MB cell dissemination and raises the possibility that curability of selected MB may be improved by pharmaceutical strategies directed towards microRNA-21.
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Affiliation(s)
- Eveline Grunder
- Oncology Department, University Children's Hospital of Zurich, Switzerland
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114
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Slade I, Murray A, Hanks S, Kumar A, Walker L, Hargrave D, Douglas J, Stiller C, Izatt L, Rahman N. Heterogeneity of familial medulloblastoma and contribution of germline PTCH1 and SUFU mutations to sporadic medulloblastoma. Fam Cancer 2011; 10:337-42. [PMID: 21188540 DOI: 10.1007/s10689-010-9411-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PTCH1 and SUFU are both regulators of the sonic hedgehog signalling pathway. Germline inactivating mutations in both genes are associated with multisystem phenotypes including medulloblastoma. Somatic inactivating mutations in PTCH1 and SUFU each occur in approximately 10% of medulloblastomas. Recently, SUFU mutations were reported in familial medulloblastoma pedigrees without additional phenotypic features. We sought to further investigate the contribution of germline PTCH1 and SUFU mutations to familial and sporadic medulloblastoma. We performed full-gene mutational analysis of both PTCH1 and SUFU in three familial medulloblastoma pedigrees and 83 individuals with sporadic non-familial medulloblastoma. We identified no mutations in PTCH1 or SUFU in the three familial medulloblastoma pedigrees. We identified no PTCH1 mutations and two SUFU mutations that cause premature protein truncating in the series of sporadic non-familial medulloblastomas. The SUFU mutations were identified in two of the 16 individuals with desmoplastic medulloblastomas. These data indicate that familial medulloblastoma is a genetically heterogeneous disorder with at least one further susceptibility gene to be discovered. Furthermore, although both PTCH1 and SUFU play a key role in the sonic hedgehog signalling pathway, PTCH1 does not make an appreciable contribution to non-familial sporadic medulloblastoma, whereas inactivating germline mutations of SUFU cause ~2-3% of sporadic medulloblastomas and > 10% of desmoplastic medulloblastomas.
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Affiliation(s)
- Ingrid Slade
- Section of Cancer Genetics, Institute of Cancer Research and Royal Marsden Hospital, 15 Cotswold Road, Sutton, Surrey SM2 5NG, UK
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115
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Lin W, Lin Y, Li J, Harding HP, Ron D, Jamison S. A deregulated integrated stress response promotes interferon-γ-induced medulloblastoma. J Neurosci Res 2011; 89:1586-95. [PMID: 21688289 DOI: 10.1002/jnr.22693] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 04/11/2011] [Accepted: 04/15/2011] [Indexed: 01/09/2023]
Abstract
Endoplasmic reticulum (ER) stress activates pancreatic ER kinase (PERK), which coordinates an adaptive program known as the integrated stress response (ISR) by phosphorylating translation initiation factor 2α (eIF2α). There is evidence that the ISR is involved in tumor development. Recent studies also show that the ISR stimulates the expression of vascular endothelial growth factor A (VEGF-A), a master regulator of angiogenesis. Our previous studies have demonstrated that enforced expression of interferon-γ (IFNγ) in the central nervous system during development induces sonic hedgehog expression and leads to cerebellar dysplasia or medulloblastoma. Here we report that PERK was activated in cerebellar dysplasia and medulloblastoma in IFNγ-expressing mice. We found that inactivation of the growth arrest and DNA damage 34 (GADD34) gene, encoding the stress-inducible regulatory subunit of a phosphatase complex that dephosphorylates eIF2α, enhanced ISR signaling and facilitated medulloblastoma formation in IFNγ-expressing mice. Moreover, we found that the induction of VEGF-A and enhanced angiogenesis were associated with medulloblastoma formation in IFNγ-expressing mice on the GADD34 mutation background. Thus, our data provide genetic evidence that the ISR facilitates medulloblastoma development.
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Affiliation(s)
- Wensheng Lin
- Department of Cell Biology and Neuroscience, University of South Alabama College of Medicine, Mobile, Alabama, USA.
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116
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Vulcani-Freitas TM, Saba-Silva N, Cappellano A, Cavalheiro S, Toledo SRCD. PRAME gene expression profile in medulloblastoma. ARQUIVOS DE NEURO-PSIQUIATRIA 2011; 69:9-12. [PMID: 21359415 DOI: 10.1590/s0004-282x2011000100003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Accepted: 07/15/2010] [Indexed: 12/20/2022]
Abstract
Medulloblastoma is the most common malignant tumors of central nervous system in the childhood. The treatment is severe, harmful and, thus, has a dismal prognosis. As PRAME is present in various cancers, including meduloblastoma, and has limited expression in normal tissues, this antigen can be an ideal vaccine target for tumor immunotherapy. In order to find a potential molecular target, we investigated PRAME expression in medulloblastoma fragments and we compare the results with the clinical features of each patient. Analysis of gene expression was performed by real-time quantitative PCR from 37 tumor samples. The Mann-Whitney test was used to analysis the relationship between gene expression and clinical characteristics. Kaplan-Meier curves were used to evaluate survival. PRAME was overexpressed in 84% samples. But no statistical association was found between clinical features and PRAME overexpression. Despite that PRAME gene could be a strong candidate for immunotherapy since it is highly expressed in medulloblastomas.
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117
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Abstract
Medulloblastoma is the most common malignant brain tumor in children. The treatment strategy in this tumor mainly includes surgery and radiotherapy, but chemotherapy has been successfully applied in medulloblastoma. The survival rates have improved over the last decade with chemotherapy. The most important prognostic factors were the amount and the extent of metastases, surgery and age. Risk factors have been defined in recent years, but chemotherapy has not been planned according to these defined risk factors on a worldwide basis. The aim of this article was to examine the use of chemotherapy in childhood medulloblastoma according to risk group. A secondary aim was to examine high-dose chemotherapy with autologous stem cell transplantation and the treatment of infant medulloblastoma.
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Affiliation(s)
- Ali Varan
- Department of Pediatric Oncology, Hacettepe University, Institute of Oncology, 06100 Ankara, Turkey.
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118
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Priller M, Pöschl J, Abrão L, von Bueren AO, Cho YJ, Rutkowski S, Kretzschmar HA, Schüller U. Expression of FoxM1 is required for the proliferation of medulloblastoma cells and indicates worse survival of patients. Clin Cancer Res 2011; 17:6791-801. [PMID: 21918172 DOI: 10.1158/1078-0432.ccr-11-1214] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE The transcription factor Forkhead box M1 (FoxM1) is a key regulator of cell-cycle progression. It is involved in the development of multiple organs, and we have previously reported on its important role for the mitotic entry of cerebellar granule neuron precursors. Constitutive expression of FoxM1 is required for the growth of multiple cancer types. This study aimed to determine its role in medulloblastoma, the most frequent malignant brain tumor in childhood that can derive from cerebellar granule neuron precursors. EXPERIMENTAL DESIGN We evaluated the expression of FoxM1 together with its prognostic value in two independent series of human medulloblastoma samples using immunohistochemistry (n = 43) and gene expression arrays (n = 193). The functional impact of FoxM1 expression was characterized by knockdown experiments in four human medulloblastoma cell lines, and the thiazole antibiotic siomycin A was tested to downregulate FoxM1 and inhibit tumor cell growth. RESULTS FoxM1 was highly expressed in all subtypes of medulloblastoma. Importantly, expression levels of FoxM1 significantly correlated with unfavorable clinical outcome in univariate analysis (P = 0.0005), and FoxM1 was identified as an independent prognostic marker by multivariate analysis (P = 0.037). Knockdown of FoxM1 in medulloblastoma cell lines resulted in a significant decrease of cell viability which was caused by a failure in mitotic spindle formation and caspase-dependent mitotic catastrophe. Siomycin A significantly inhibited the expression of FoxM1 and the growth of medulloblastoma cells. CONCLUSIONS FoxM1 may be used as an additional prognostic marker and may represent a potential novel target to treat patients suffering from medulloblastoma.
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Affiliation(s)
- Markus Priller
- Center for Neuropathology, Ludwig-Maximilians-University, Munich, Germany
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119
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MiR-34a targeting of Notch ligand delta-like 1 impairs CD15+/CD133+ tumor-propagating cells and supports neural differentiation in medulloblastoma. PLoS One 2011; 6:e24584. [PMID: 21931765 PMCID: PMC3171461 DOI: 10.1371/journal.pone.0024584] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 08/14/2011] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Through negative regulation of gene expression, microRNAs (miRNAs) can function as oncosuppressors in cancers, and can themselves show altered expression in various tumor types. Here, we have investigated medulloblastoma tumors (MBs), which arise from an early impairment of developmental processes in the cerebellum, where Notch signaling is involved in many of the cell-fate-determining stages. Notch regulates a subset of MB cells that have stem-cell-like properties and can promote tumor growth. On the basis of this evidence, we hypothesized that miRNAs targeting the Notch pathway can regulate these phenomena, and can be used in anti-cancer therapies. METHODOLOGY/PRINCIPAL FINDINGS In a screening of potential targets within Notch signaling, miR-34a was seen to be a regulator of the Notch pathway through its targeting of Notch ligand Delta-like 1 (Dll1). Down-regulation of Dll1 expression by miR-34a negatively regulates cell proliferation, and induces apoptosis and neural differentiation in MB cells. Using an inducible tetracycline on-off model of miR-34a expression, we show that in Daoy MB cells, Dll1 is the first target that is regulated in MB, as compared to the other targets analyzed here: Cyclin D1, cMyc and CDK4. MiR-34a expression negatively affects CD133(+)/CD15(+) tumor-propagating cells, then we assay through reverse-phase proteomic arrays, Akt and Stat3 signaling hypo-phosphorylation. Adenoviruses carrying the precursor miR-34a induce neurogenesis of tumor spheres derived from a genetic animal model of MB (Patch1(+/-) p53(-/-)), thus providing further evidence that the miR-34a/Dll1 axis controls both autonomous and non autonomous signaling of Notch. In vivo, miR-34a overexpression carried by adenoviruses reduces tumor burden in cerebellum xenografts of athymic mice, thus demonstrating an anti-tumorigenic role of miR-34a in vivo. CONCLUSIONS/SIGNIFICANCE Despite advances in our understanding of the pathogenesis of MB, one-third of patients with MB remain incurable. Here, we show that stable nucleic-acid-lipid particles carrying mature miR-34a can target Dll1 in vitro and show equal effects to those of adenovirus miR-34a cell infection. Thus, this technology forms the basis for their therapeutic use for the delivery of miR-34a in brain-tumor treatment, with no signs of toxicity described to date in non-human primate trials.
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Integrated analysis of miRNA and mRNA expression in childhood medulloblastoma compared with neural stem cells. PLoS One 2011; 6:e23935. [PMID: 21931624 PMCID: PMC3170291 DOI: 10.1371/journal.pone.0023935] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 07/28/2011] [Indexed: 11/29/2022] Open
Abstract
Medulloblastoma (MB) is the most common malignant brain tumor in children and a leading cause of cancer-related mortality and morbidity. Several molecular sub-types of MB have been identified, suggesting they may arise from distinct cells of origin. Data from animal models indicate that some MB sub-types arise from multipotent cerebellar neural stem cells (NSCs). Hence, microRNA (miRNA) expression profiles of primary MB samples were compared to CD133+ NSCs, aiming to identify deregulated miRNAs involved in MB pathogenesis. Expression profiling of 662 miRNAs in primary MB specimens, MB cell lines, and human CD133+ NSCs and CD133− neural progenitor cells was performed by qRT-PCR. Clustering analysis identified two distinct sub-types of MB primary specimens, reminiscent of sub-types obtained from their mRNA profiles. 21 significantly up-regulated and 12 significantly down-regulated miRNAs were identified in MB primary specimens relative to CD133+ NSCs (p<0.01). The majority of up-regulated miRNAs mapped to chromosomal regions 14q32 and 17q. Integration of the predicted targets of deregulated miRNAs with mRNA expression data from the same specimens revealed enrichment of pathways regulating neuronal migration, nervous system development and cell proliferation. Transient over-expression of a down-regulated miRNA, miR-935, resulted in significant down-regulation of three of the seven predicted miR-935 target genes at the mRNA level in a MB cell line, confirming the validity of this approach. This study represents the first integrated analysis of MB miRNA and mRNA expression profiles and is the first to compare MB miRNA expression profiles to those of CD133+ NSCs. We identified several differentially expressed miRNAs that potentially target networks of genes and signaling pathways that may be involved in the transformation of normal NSCs to brain tumor stem cells. Based on this integrative approach, our data provide an important platform for future investigations aimed at characterizing the role of specific miRNAs in MB pathogenesis.
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Combination chemotherapy with ifosfamide, cisplatin, and etoposide for medulloblastoma: single-institute experience and differences in efficacy for subgroups of medulloblastoma. Childs Nerv Syst 2011; 27:1399-406. [PMID: 21590299 DOI: 10.1007/s00381-011-1485-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 05/05/2011] [Indexed: 10/18/2022]
Abstract
PURPOSE Treatment for medulloblastoma consists of surgical resection, radiation therapy, and chemotherapy. In Japan, ICE chemotherapy consisting of cisplatin, ifosfamide, and etoposide is one of the most common regimens. Here, we summarize the toxicity and efficacy of ICE chemotherapy and evaluate the usefulness of the recently introduced molecular classification scheme to predict the outcome. METHODS Seventeen patients with medulloblastoma treated by ICE chemotherapy as an initial therapy at our institute were retrospectively reviewed. Eleven were categorized in the standard-risk group and six in the high-risk group. All patients underwent maximum cytoreductive surgery, radiation therapy, and ICE chemotherapy. Operative specimens were subjected to immunohistochemical staining using four antibodies-DKK1, SFRP1, NPR3, and KCNA1-to classify the cases into four subgroups, WNT group, SHH group, group C, and group D, respectively. RESULTS ICE chemotherapy following surgery and radiation therapy was tolerable in most patients with appropriate management, although myelosuppression and hearing disturbance occurred. There was no significant difference in survival between patients with standard-risk disease and high-risk disease. Five-year survival and 5-year progression-free survival for the 17 patients were 80.7% and 63.5%, respectively. Three patients were classified as WNT group, 2 as SHH group, 1 as group C, and 11 as group D. Group D tended to have poorer prognosis after ICE chemotherapy. CONCLUSIONS ICE chemotherapy was tolerable and active against medulloblastomas. Patients categorized as group D tended to have worse outcome after ICE chemotherapy.
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Faria CMC, Rutka JT, Smith C, Kongkham P. Epigenetic mechanisms regulating neural development and pediatric brain tumor formation. J Neurosurg Pediatr 2011; 8:119-32. [PMID: 21806352 DOI: 10.3171/2011.5.peds1140] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Pediatric brain tumors are the leading cause of cancer-related death in children, and among them, embryonal tumors represent the largest group with an associated poor prognosis and long-term morbidity for survivors. The field of cancer epigenetics has emerged recently as an important area of investigation and causation of a variety of neoplasms, and is defined as alterations in gene expression without changes in DNA sequence. The best studied epigenetic modifications are DNA methylation, histone modifications, and RNA-based mechanisms. These modifications play an important role in normal development and differentiation but their dysregulation can lead to altered gene function and cancer. In this review the authors describe the mechanisms of normal epigenetic regulation, how they interplay in neuroembryogenesis, and how these can cause brain tumors in children when dysregulated. The potential use of epigenetic markers to design more effective treatment strategies for children with malignant brain tumors is also discussed.
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Affiliation(s)
- Claudia M C Faria
- Division of Neurosurgery, Department of Surgery, The University of Toronto, Ontario, Canada
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SPARC mediates Src-induced disruption of actin cytoskeleton via inactivation of small GTPases Rho-Rac-Cdc42. Cell Signal 2011; 23:1978-87. [PMID: 21798346 DOI: 10.1016/j.cellsig.2011.07.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 07/12/2011] [Indexed: 01/13/2023]
Abstract
The matricellular glycoprotein Secreted Protein Acidic and Rich in Cysteine (SPARC) plays an important role in the regulation of cell adhesion and proliferation as well as in tumorigenesis and metastasis. Earlier, we reported that, in addition to its potent anti-angiogenic functions, SPARC also induces apoptosis in medulloblastoma cells, mediated by autophagy. We therefore sought to investigate the underlying molecular mechanism through which SPARC inhibits migration and invasion of Daoy medulloblastoma cells, both in vitro and in vivo. For this study, we used SPARC-overexpressing stable Daoy medulloblastoma cells. SPARC overexpression in Daoy medulloblastoma cells inhibited migration and invasion in vitro. Additionally, SPARC overexpression significantly suppressed the activity of Rho, Rac and Cdc42, which all regulate the actin cytoskeleton. This suppression was accompanied by an increase in the phosphorylation of Src at Tyr-416, which led to a loss of actin stress fibers and focal contacts and a decrease in the phosphorylation level of cofilin. The reduced phosphorylation level of cofilin, which is indicative of receding Rho function, in turn led to inhibition of active Rho A. To confirm the role of SPARC in inhibition of migration and invasion of Daoy medulloblastoma cells, we transfected parental and SPARC-overexpressing Daoy cells with a plasmid vector carrying siRNA against SPARC. Transfection with SPARC siRNA reversed Src-mediated disruption of the cytoskeleton organization as well as dephosphorylation of cofilin and activation of Rho A. Taken together, these results establish SPARC as an effector of Src-induced cytoskeleton disruption in Daoy medulloblastoma cells, which subsequently led to decreased migration and invasion.
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Identification and characterization of KCASH2 and KCASH3, 2 novel Cullin3 adaptors suppressing histone deacetylase and Hedgehog activity in medulloblastoma. Neoplasia 2011; 13:374-85. [PMID: 21472142 DOI: 10.1593/neo.101630] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 01/27/2011] [Accepted: 01/27/2011] [Indexed: 11/18/2022] Open
Abstract
Medulloblastoma is the most common pediatric malignant brain tumor, arising from aberrant cerebellar precursors' development, a process mainly controlled by Hedgehog (Hh) signaling pathway. Histone deacetylase HDAC1 has been recently shown to modulate Hh signaling, deacetylating its effectors Gli1/2 and enhancing their transcriptional activity. Therefore, HDAC may represent a potential therapeutic target for Hh-dependent tumors, but still little information is available on the physiological mechanisms of HDAC regulation. The putative tumor suppressor REN(KCTD11) acts through ubiquitination-dependent degradation of HDAC1, thereby affecting Hh activity and medulloblastoma growth. We identify and characterize here two REN(KCTD11) homologues, defining a new family of proteins named KCASH, as "KCTD containing, Cullin3 adaptor, suppressor of Hedgehog." Indeed, the novel genes (KCASH2(KCTD21) and KCASH3(KCTD6)) share with REN(KCTD11) a number of features, such as a BTB domain required for the formation of a Cullin3 ubiquitin ligase complex and HDAC1 ubiquitination and degradation capability, suppressing the acetylation-dependent Hh/Gli signaling. Expression of KCASH2 and -3 is observed in cerebellum, whereas epigenetic silencing and allelic deletion are observed in human medulloblastoma. Rescuing KCASHs expression reduces the Hedgehog-dependent medulloblastoma growth, suggesting that loss of members of this novel family of native HDAC inhibitors is crucial in sustaining Hh pathway-mediated tumorigenesis. Accordingly, they might represent a promising class of endogenous "agents" through which this pathway may be targeted.
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Marino AM, Sofiadis A, Baryawno N, Johnsen JI, Larsson C, Vukojević V, Ekström TJ. Enhanced effects by 4-phenylbutyrate in combination with RTK inhibitors on proliferation in brain tumor cell models. Biochem Biophys Res Commun 2011; 411:208-12. [PMID: 21726539 DOI: 10.1016/j.bbrc.2011.06.141] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Accepted: 06/21/2011] [Indexed: 01/29/2023]
Abstract
We have investigated in vitro effects of anticancer therapy with the histone deacetylase inhibitor (HDACi) 4-phenylbutyrate (4-PB) combined with receptor tyrosine kinase inhibitors (RTKi) gefitinib or vandetanib on the survival of glioblastoma (U343MGa) and medulloblastoma (D324Med) cells. In comparison with individual effects of these drugs, combined treatment with gefitinib/4-PB or vandetanib/4-PB resulted in enhanced cell killing and reduced clonogenic survival in both cell lines. Our results suggest that combined treatment using HDACi and RTKi may beneficially affect the outcome of cancer therapy.
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Affiliation(s)
- Ana-Maria Marino
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Abstract
Bmi1 is a key stem cell regulatory gene implicated in the pathogenesis of many aggressive cancers, including medulloblastoma. Overexpression of Bmi1 promotes cell proliferation and is required for hedgehog (Hh) pathway-driven tumorigenesis. This study aimed to determine if Sonic hedgehog (Shh) modulates the key stem cell regulatory gene Bmi1 in childhood medulloblastoma brain tumor-initiating cells (BTICs). Although current literature suggests that there is a correlation between Shh pathway genes and Bmi1 expression, it is unclear whether there is indeed a direct regulatory mechanism. To address whether Shh induces expression of Bmi1, stem cell-enriched populations from medulloblastoma cell lines and primary samples were treated with Shh ligand and KAAD-cyclopamine (Shh antagonist). Our data indicate that Bmi1 expression positively correlates with increasing Shh ligand concentrations. Chromatin immunoprecipitation reveals that Gli1 preferentially binds to the Bmi1 promoter, and Bmi1 transcript levels are increased and decreased by Gli1 overexpression and downregulation, respectively. Knockdown experiments of Bmi1 in vitro and in vivo demonstrate that Hh signaling not only drives Bmi1 expression, but a feedback mechanism exists wherein downstream effectors of Bmi1 may, in turn, activate Hh pathway genes. These findings implicate Bmi1 and Hh as mutually indispensable pathways in medulloblastoma BTIC maintenance. Recent molecular characterization of medulloblastoma also reveals that Bmi1 is overexpressed across all subgroups of medulloblastoma, particularly in the most aggressive subtypes. Lastly, despite recent identification of BTIC markers, the molecular characterization of these cell populations remains unclear. In this work, we propose that the BTIC marker CD133 may segregate a cell population with a Hh-receptor phenotype, thus demonstrating a cell-cell interaction between the CD133+ Hh receptor cells and the CD133- Hh-secreting cells.
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Faccion RS, Ferreira RM, Grabois MF, Fonseca TC, de Oliveira JA, Maia RC. Lack of Prognostic Significance of Survivin in Pediatric Medulloblastoma. Pathol Oncol Res 2011; 17:899-908. [DOI: 10.1007/s12253-011-9401-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 04/06/2011] [Indexed: 11/29/2022]
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Bhoopathi P, Chetty C, Dontula R, Gujrati M, Dinh DH, Rao JS, Lakka SS. SPARC stimulates neuronal differentiation of medulloblastoma cells via the Notch1/STAT3 pathway. Cancer Res 2011; 71:4908-19. [PMID: 21613407 DOI: 10.1158/0008-5472.can-10-3395] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Secreted protein acidic and rich in cysteine (SPARC) participates in the regulation of morphogenesis and cellular differentiation through its modulation of cell-matrix interactions. We previously reported that SPARC expression significantly impairs medulloblastoma tumor growth in vivo. In this study, we show that adenoviral-mediated overexpression of SPARC cDNA (Ad-DsRed-SP) elevated the expression of the neuronal markers NeuN, nestin, neurofilament, and MAP-2 in medulloblastoma cells and induced neuron-like differentiation. SPARC overexpression decreased STAT3 phosphorylation; constitutive expression of STAT3 reversed SPARC-mediated expression of neuronal markers. We also show that Notch signaling is suppressed in the presence of SPARC, as well as the Notch effector basic helix-loop-helix (bHLH) transcription factor hairy and enhancer of split 1 (HES1). Notch signaling was found to be responsible for the decreased STAT3 phosphorylation in response to SPARC expression. Furthermore, expression of SPARC decreased the production of interleukin 6 (IL-6) and supplemented IL-6-abrogated, SPARC-mediated suppression of Notch signaling and expression of neuronal markers. Immunohistochemical analysis of tumor sections from mice treated with Ad-DsRed-SP showed increased immunoreactivity for the neuronal markers and a decrease in Notch1 expression and phosphorylation of STAT3. Taken together, our results suggest that SPARC induces expression of neuronal markers in medulloblastoma cells through its inhibitory effect on IL-6-regulated suppression of Notch pathway-mediated STAT3 signaling, thus giving further support to the potential use of SPARC as a therapeutic candidate for medulloblastoma treatment. Findings show that SPARC-induced neuronal differentiation can sensitize medulloblastoma cells for therapy.
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Affiliation(s)
- Praveen Bhoopathi
- Program of Cancer Biology, Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, IL 61605, USA
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Expression of BARHL1 in medulloblastoma is associated with prolonged survival in mice and humans. Oncogene 2011; 30:4721-30. [PMID: 21602885 DOI: 10.1038/onc.2011.173] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Medulloblastoma is the most common malignant brain tumor in childhood, and development of targeted therapies is highly desired. Although the molecular mechanisms of malignant transformation are not fully understood, it is known that medulloblastomas may arise from cerebellar granule neuron precursors. The homeodomain transcription factor Barhl1 is known to regulate migration and survival of granule cell precursors, but its functional role in medulloblastoma is unknown. We show here that the expression of BARHL1 is significantly upregulated during human cerebellar development and in human medulloblastoma samples as compared with the normal adult cerebellum. We also detected high levels of Barhl1 expression in medulloblastomas of Math1-cre:SmoM2 mice, a mouse model for Sonic hedgehog-associated medulloblastomas that we developed previously. To investigate Barhl1 function in vivo during tumor development, we generated Barhl1(-/-)Math1-cre:SmoM2 mice. Interestingly, tumors that developed in these mice displayed increased mitotic activity and decreased neuronal differentiation. Moreover, survival of these mice was significantly decreased. Similarly, low expression of BARHL1 in human medulloblastoma cases was associated with a less favorable prognosis for patients. These results suggest that the expression of Barhl1 decelerates tumor growth both in human and in murine medulloblastomas and should be further investigated with respect to potential implications for individualized therapeutic strategies.
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Gupta T, Jalali R. Molecular biology of medulloblastoma: bridging the gap between research and practice. Expert Rev Neurother 2011; 11:491-4. [DOI: 10.1586/ern.11.22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Menghi F, Jacques TS, Barenco M, Schwalbe EC, Clifford SC, Hubank M, Ham J. Genome-wide analysis of alternative splicing in medulloblastoma identifies splicing patterns characteristic of normal cerebellar development. Cancer Res 2011; 71:2045-55. [PMID: 21248070 PMCID: PMC3060131 DOI: 10.1158/0008-5472.can-10-2519] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Alternative splicing is an important mechanism for the generation of protein diversity at a post-transcriptional level. Modifications in the splicing patterns of several genes have been shown to contribute to the malignant transformation of different tissue types. In this study, we used the Affymetrix Exon arrays to investigate patterns of differential splicing between pediatric medulloblastomas and normal cerebellum on a genome-wide scale. Of the 1,262 genes identified as potentially generating tumor-associated splice forms, we selected 14 examples of differential splicing of known cassette exons and successfully validated 11 of them by reverse transcriptase PCR. The pattern of differential splicing of three validated events was characteristic for the molecular subset of sonic hedgehog (Shh)-driven medulloblastomas, suggesting that their unique gene signature includes the expression of distinctive transcript variants. Generally, we observed that tumor and normal fetal cerebellar samples shared significantly lower exon inclusion rates than normal adult cerebellum. We investigated whether tumor-associated splice forms were expressed in primary cultures of Shh-dependent mouse cerebellar granule cell precursors (GCP) and found that Shh caused a decrease in the cassette exon inclusion rate of five of the seven tested genes. Furthermore, we observed a significant increase in exon inclusion between postnatal days 7 and 14 of mouse cerebellar development, at the time when GCPs mature into postmitotic neurons. We conclude that inappropriate splicing frequently occurs in human medulloblastomas and may be linked to the activation of developmental signaling pathways and a failure of cerebellar precursor cells to differentiate.
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Affiliation(s)
- Francesca Menghi
- Molecular Haematology and Cancer Biology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
| | - Thomas S. Jacques
- Neural Development Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
- Department of Histopathology, Great Ormond Street Hospital for Children NHS Trust, London, WC1N 3JH, UK
| | - Martino Barenco
- Molecular Haematology and Cancer Biology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
| | - Ed C. Schwalbe
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Steven C. Clifford
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Mike Hubank
- Molecular Haematology and Cancer Biology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
| | - Jonathan Ham
- Molecular Haematology and Cancer Biology Unit, UCL Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK
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GU CHUNYU, YOKOTA NAOKI, GAO YUN, YAMAMOTO JUNKOH, TOKUYAMA TSUTOMU, NAMBA HIROKI. Gene expression of growth signaling pathways is up-regulated in CD133-positive medulloblastoma cells. Oncol Lett 2011; 2:357-361. [PMID: 22866088 PMCID: PMC3410605 DOI: 10.3892/ol.2011.235] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 12/30/2010] [Indexed: 12/31/2022] Open
Abstract
Medulloblastoma (MB) is the most common malignant brain tumor in children. Cancer initiating cells (CICs) have been proposed to be involved in the development of brain tumors including MB. Prominin-1 antigen (CD133) is a candidate surface molecular marker for CICs. In the present study, CD133-positive cells were isolated from human Daoy MB cells and their gene expression was compared with that of control Daoy cells. DNA microarray analysis revealed that there were 398 up-regulated genes (>2-fold increase) and 318 down-regulated genes (<50% decrease) in the CD133-positive cell-enriched fractions. Up-regulated genes included neuregulin-1, cyclin D1, cyclin-dependent kinase 6, vascular endothelial growth factor, inhibin β A, promyelocytic leukemia gene, MYC, and hairy enhancer of split-1, which are components of growth signaling pathways. Molecular studies suggest that developmentally regulated signals important for stem cell maintenance are also involved in MB tumorigenesis. Moreover, these molecules can serve as novel targets for MB treatment.
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Affiliation(s)
- CHUNYU GU
- Department of Neurosurgery, Hamamatsu University School of Medicine, Higashi-ku, Hamamatsu 431-3192
| | - NAOKI YOKOTA
- Department of Neurosurgery, Hamamatsu University School of Medicine, Higashi-ku, Hamamatsu 431-3192
- Yokohama CyberKnife Center, Asahi-ku, Yokohama 241-0014, Japan
| | - YUN GAO
- Department of Neurosurgery, Hamamatsu University School of Medicine, Higashi-ku, Hamamatsu 431-3192
| | - JUNKOH YAMAMOTO
- Department of Neurosurgery, Hamamatsu University School of Medicine, Higashi-ku, Hamamatsu 431-3192
| | - TSUTOMU TOKUYAMA
- Department of Neurosurgery, Hamamatsu University School of Medicine, Higashi-ku, Hamamatsu 431-3192
| | - HIROKI NAMBA
- Department of Neurosurgery, Hamamatsu University School of Medicine, Higashi-ku, Hamamatsu 431-3192
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Tamayo P, Cho YJ, Tsherniak A, Greulich H, Ambrogio L, Schouten-van Meeteren N, Zhou T, Buxton A, Kool M, Meyerson M, Pomeroy SL, Mesirov JP. Predicting relapse in patients with medulloblastoma by integrating evidence from clinical and genomic features. J Clin Oncol 2011; 29:1415-23. [PMID: 21357789 DOI: 10.1200/jco.2010.28.1675] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
PURPOSE Despite significant progress in the molecular understanding of medulloblastoma, stratification of risk in patients remains a challenge. Focus has shifted from clinical parameters to molecular markers, such as expression of specific genes and selected genomic abnormalities, to improve accuracy of treatment outcome prediction. Here, we show how integration of high-level clinical and genomic features or risk factors, including disease subtype, can yield more comprehensive, accurate, and biologically interpretable prediction models for relapse versus no-relapse classification. We also introduce a novel Bayesian nomogram indicating the amount of evidence that each feature contributes on a patient-by-patient basis. PATIENTS AND METHODS A Bayesian cumulative log-odds model of outcome was developed from a training cohort of 96 children treated for medulloblastoma, starting with the evidence provided by clinical features of metastasis and histology (model A) and incrementally adding the evidence from gene-expression-derived features representing disease subtype-independent (model B) and disease subtype-dependent (model C) pathways, and finally high-level copy-number genomic abnormalities (model D). The models were validated on an independent test cohort (n = 78). RESULTS On an independent multi-institutional test data set, models A to D attain an area under receiver operating characteristic (au-ROC) curve of 0.73 (95% CI, 0.60 to 0.84), 0.75 (95% CI, 0.64 to 0.86), 0.80 (95% CI, 0.70 to 0.90), and 0.78 (95% CI, 0.68 to 0.88), respectively, for predicting relapse versus no relapse. CONCLUSION The proposed models C and D outperform the current clinical classification schema (au-ROC, 0.68), our previously published eight-gene outcome signature (au-ROC, 0.71), and several new schemas recently proposed in the literature for medulloblastoma risk stratification.
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Affiliation(s)
- Pablo Tamayo
- Eli and Edythe Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02142, USA
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Coco S, Valdora F, Bonassi S, Scaruffi P, Stigliani S, Oberthuer A, Berthold F, Andolfo I, Servidei T, Riccardi R, Basso E, Iolascon A, Tonini GP. Chromosome 9q and 16q loss identified by genome-wide pooled-analysis are associated with tumor aggressiveness in patients with classic medulloblastoma. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2011; 15:273-80. [PMID: 21348762 DOI: 10.1089/omi.2010.0103] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Medulloblastoma (MB) is one of the most aggressive pediatric brain tumor. We report genome-wide pooled-analysis of classic MB variant of patients over 3 years of age at diagnosis. We combined array comparative genomic hybridization (aCGH) results from experimental analysis (31 cases) with two public databases (55 cases) in a final evaluation of 86 MBs. The most common chromosome structural aberrations were gains of 17q (45.3%), 1q (22.1%), and losses of 8p (15.1%), 10q (19.8%), 17p (37.2%), and 16q (16.3%). Isochromome (17q) was observed in 29.1% MBs. A significant association between poor patients survival and losses of 9q (p < 0.0023), 10q (p < 0.012), and 16q (p < 0.036) was observed. Univariate analysis showed association of 9q loss (p < 0.008) and 16q loss (p = 0.05) with adverse overall survival (OS). Chromosome 6 monosomy was a protective event although statistically borderline (p = 0.066). After adjusting for confounding factors, a poor OS was found for patients whose tumor has 9q loss [hazard ratio (HR) = 3.97; p < 0.006) or 16q loss (HR = 2.41; p = 0.038). Our results highlight the importance of genomic studies in different MB histological variants and indicate a genotype-phenotype correlation.
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Affiliation(s)
- Simona Coco
- Translational Oncopathology, National Cancer Research Institute (IST), Genoa, Italy
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Bone morphogenetic protein-7 is a MYC target with prosurvival functions in childhood medulloblastoma. Oncogene 2011; 30:2823-35. [PMID: 21317922 DOI: 10.1038/onc.2011.10] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Medulloblastoma (MB) is the most common malignant brain tumor in children. It is known that overexpression and/or amplification of the MYC oncogene is associated with poor clinical outcome, but the molecular mechanisms and the MYC downstream effectors in MB remain still elusive. Besides contributing to elucidate how progression of MB takes place, most importantly, the identification of novel MYC-target genes will suggest novel candidates for targeted therapy in MB. A group of 209 MYC-responsive genes was obtained from a complementary DNA microarray analysis of a MB-derived cell line, following MYC overexpression and silencing. Among the MYC-responsive genes, we identified the members of the bone morphogenetic protein (BMP) signaling pathway, which have a crucial role during the development of the cerebellum. In particular, the gene BMP7 was identified as a direct target of MYC. A positive correlation between MYC and BMP7 expression was documented by analyzing two distinct sets of primary MB samples. Functional studies in vitro using a small-molecule inhibitor of the BMP/SMAD signaling pathway reproduced the effect of the small interfering RNA-mediated silencing of BMP7. Both approaches led to a block of proliferation in a panel of MB cells and to inhibition of SMAD phosphorylation. Altogether, our findings indicate that high MYC levels drive BMP7 overexpression, promoting cell survival in MB cells. This observation suggests the potential relevance of targeting the BMP/SMAD pathway as a novel therapeutic approach for the treatment of childhood MB.
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Wu H, Pomeroy SL, Ferreira M, Teider N, Mariani J, Nakayama KI, Hatakeyama S, Tron VA, Saltibus LF, Spyracopoulos L, Leng RP. UBE4B promotes Hdm2-mediated degradation of the tumor suppressor p53. Nat Med 2011; 17:347-55. [PMID: 21317885 DOI: 10.1038/nm.2283] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Accepted: 11/30/2010] [Indexed: 11/09/2022]
Abstract
The TP53 gene (encoding the p53 tumor suppressor) is rarely mutated, although frequently inactivated, in medulloblastoma and ependymoma. Recent work in mouse models showed that the loss of p53 accelerated the development of medulloblastoma. The mechanism underlying p53 inactivation in human brain tumors is not completely understood. We show that ubiquitination factor E4B (UBE4B), an E3 and E4 ubiquitin ligase, physically interacts with p53 and Hdm2 (also known as Mdm2 in mice). UBE4B promotes p53 polyubiquitination and degradation and inhibits p53-dependent transactivation and apoptosis. Notably, silencing UBE4B expression impairs xenotransplanted tumor growth in a p53-dependent manner and overexpression of UBE4B correlates with decreased expression of p53 in these tumors. We also show that UBE4B overexpression is often associated with amplification of its gene in human brain tumors. Our data indicate that amplification and overexpression of UBE4B represent previously undescribed molecular mechanisms of inactivation of p53 in brain tumors.
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Affiliation(s)
- Hong Wu
- Heritage Medical Research Center, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
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Inhibition of NF-κB signaling commits resveratrol-treated medulloblastoma cells to apoptosis without neuronal differentiation. J Neurooncol 2010; 104:169-77. [PMID: 21161674 DOI: 10.1007/s11060-010-0496-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 12/03/2010] [Indexed: 01/05/2023]
Abstract
Resveratrol promotes differentiation and apoptosis of medulloblastoma cells by suppressing STAT3 signaling and a range of cancer-associated gene expression. However, Bcl-2, a common target of STAT3 and NF-κB signaling, is distinctly up-regulated in resveratrol-treated medulloblastoma cells, indicating potential effects of NF-κB in Bcl-2 expression and anti-medulloblastoma efficiency of resveratrol. To clarify this point, the status of NF-κB signaling and the consequence of NF-κB inhibition in UW228-2 and UW228-3 medulloblastoma cells without and with resveratrol treatment were evaluated by several experimental approaches. The results revealed that resveratrol activated NF-κB signaling in both cell lines at the 4-h treatment point, and the treated cells sequentially exhibited Bcl-2 up-regulation, neuronal-like phenotype with synaptophisin expression, and, eventually, apoptosis. Pyrrolidine dithiocarbamate (PDTC) treatment inhibited NF-κB activation and Bcl-2 expression and committed resveratrol-treated cells to apoptosis at the 8-h time point without the step of neuron-oriented differentiation. On the other hand, a single 50 μg/ml lipopolysaccharide (LPS) treatment activated NF-κB signaling accompanied with sustained proliferation and neuron-like differentiation. Tissue microarray-based immunohistochemical staining showed significantly different (P < 0.001) p65 nuclear translocation between the neurons of tumor-surrounding cerebella (10/10; 100%) and medulloblastoma tissues (20/117; 17.09%). Additionally, synaptophysin production was found in 83.64% of p65-positive and in 40.35% of p65-negative medulloblastoma cases. Our in-vitro and in-vivo results thus demonstrate the dual effects of NF-κB signaling on medulloblastoma cells by delaying resveratrol-induced apoptosis by up-regulating Bcl-2 expression or by involvement in neuronal-like differentiation in the absence of resveratrol. Therefore, appropriate inhibition of NF-κB activation may enhance the anti-medulloblastoma efficacy of resveratrol.
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138
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Stereotactic radiotherapy and radiosurgery in pediatric patients: analysis of indications and outcome. Childs Nerv Syst 2010; 26:1785-93. [PMID: 20668863 DOI: 10.1007/s00381-010-1134-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 03/18/2010] [Indexed: 10/19/2022]
Abstract
INTRODUCTION We describe indications, outcomes, and risk profiles of fractionated stereotactic radiotherapy (SRT) and single fraction "radiosurgery" (SRS) in pediatric patients compared to the adult population and evaluate the causal role of SRS and SRT in inducing new neurological complications. MATERIALS AND METHODS Six children with AVMs and 12 children with neoplastic diseases were prospectively followed for >2 years after SRT/S. The survival, control of pathology, and specified neurological complications were analyzed. In tumor patients, the median overall survival time was 45 months (range 5-103) and the median progression free survival time was 35 months (range 5-98). RESULTS Control or regression of the tumor was obtained in 83% of patients with neoplastic disease. Three patients with malignant tumors died from disease progression. In AVMs the median time follow up was 52 months (range 27-100). All AVMs were obliterated. New neurological deficits occurred in 67%. SRT/S was considered the direct cause in 25%. All the neurological deficiencies related to SRT/S were focal and related to the irradiated areas. In tumor patients, midline lesions, malignant diagnosis, and additional treatment with surgery, chemotherapy, and craniospinal irradiation seemed to increase the risk of new deficits after SRT/S. In AVM patients, a high Spetzler-Martin grade seemed to carry a higher complication risk. CONCLUSION The risk of uncontrolled tumor disease or the risk of hemorrhage of non-obliterated AVM must be balanced against the overall risks and benefits of SRT/S. Following SRT/S, the risk of worsening pre-existing deficits is relatively high. The risk of inducing new long-term deficits is relatively low.
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139
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Moreno L, Chesler L, Hargrave D, Eccles SA, Pearson ADJ. Preclinical drug development for childhood cancer. Expert Opin Drug Discov 2010; 6:49-64. [DOI: 10.1517/17460441.2011.537652] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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140
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Molecular diagnostics of CNS embryonal tumors. Acta Neuropathol 2010; 120:553-66. [PMID: 20882288 DOI: 10.1007/s00401-010-0751-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Revised: 09/20/2010] [Accepted: 09/22/2010] [Indexed: 12/18/2022]
Abstract
Tremendous progress has recently been made in both molecular subgrouping, and the establishment of prognostic biomarkers for embryonal brain tumors, particularly medulloblastoma. Several prognostic biomarkers that were initially identified in retrospective cohorts of medulloblastoma, including MYC and MYCN amplification, nuclear β-catenin accumulation, and chromosome 17 aberrations have now been validated in clinical trials. Moreover, molecular subgroups based on distinct transcriptome profiles have been consistently reported from various groups on different platforms demonstrating that the concept of distinct medulloblastoma subgroups is very robust. Well-described subgroups of medulloblastomas include tumors showing wingless signaling pathway (Wnt) activation, and another characterized by sonic hedgehog pathway activity. Two or more additional subgroups were consistently reported to contain the vast majority of high-risk tumors, including most tumors with metastatic disease at diagnosis and/or large cell/anaplastic histology. Several years ago, atypical teratoid rhabdoid tumor (AT/RT) was recognized as a separate entity based on its distinct biology and particularly aggressive clinical behavior. These tumors may occur supra or infratentorially and are usually found to have genetic alterations of SMARCB1 (INI1/hSNF5), a tumor suppressor gene located on chromosome 22q. Subsequent loss of SMARCB1 protein expression comprises a relatively specific and sensitive diagnostic marker for AT/RT. For CNS primitive neuroectodermal tumors (CNS PNETs), a consistent finding has been that they are molecularly distinct from medulloblastoma. Furthermore, a distinct fraction of CNS PNETs with particularly poor prognosis only occurring in young children was delineated, which was previously labeled ependymoblastoma or embryonal tumor with abundant neuropil and true rosettes (ETANTR) and which is morphologically characterized by the presence of multilayered "ependymoblastic" rosettes. This group of tumors shows a unique cytogenetic abnormality not seen in other brain tumors: focal amplification of a micro-RNA cluster at chromosome 19q13.42, which has never been found to be amplified in other CNS PNETs, medulloblastoma or AT/RT. In summary, these consistent findings have significantly contributed to our ability to sub-classify embryonal brain tumors into clinically and biologically meaningful strata and, for some of the subgroups, have led to the identification of specific targets for future development of molecularly targeted therapies.
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Nalla AK, Asuthkar S, Bhoopathi P, Gujrati M, Dinh DH, Rao JS. Suppression of uPAR retards radiation-induced invasion and migration mediated by integrin β1/FAK signaling in medulloblastoma. PLoS One 2010; 5:e13006. [PMID: 20886051 PMCID: PMC2945321 DOI: 10.1371/journal.pone.0013006] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 08/30/2010] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Despite effective radiotherapy for the initial stages of cancer, several studies have reported the recurrence of various cancers, including medulloblastoma. Here, we attempt to capitalize on the radiation-induced aggressive behavior of medulloblastoma cells by comparing the extracellular protease activity and the expression pattern of molecules, known to be involved in cell adhesion, migration and invasion, between non-irradiated and irradiated cells. METHODOLOGY/PRINCIPAL FINDINGS We identified an increase in invasion and migration of irradiated compared to non-irradiated medulloblastoma cells. RT-PCR analysis confirmed increased expression of uPA, uPAR, focal adhesion kinase (FAK), N-Cadherin and integrin subunits (e.g., α3, α5 and β1) in irradiated cells. Furthermore, we noticed a ∼2-fold increase in tyrosine phosphorylation of FAK in irradiated cells. Immunoprecipitation studies confirmed increased interaction of integrin β1 and FAK in irradiated cells. In addition, our results show that overexpression of uPAR in cancer cells can mimic radiation-induced activation of FAK signaling. Moreover, by inhibiting FAK phosphorylation, we were able to reduce the radiation-induced invasiveness of the cancer cells. In this vein, we studied the effect of siRNA-mediated knockdown of uPAR on cell migration and adhesion in irradiated and non-irradiated medulloblastoma cells. Downregulation of uPAR reduced the radiation-induced adhesion, migration and invasion of the irradiated cells, primarily by inhibiting phosphorylation of FAK, Paxillin and Rac-1/Cdc42. As observed from the immunoprecipitation studies, uPAR knockdown reduced interaction among the focal adhesion molecules, such as FAK, Paxillin and p130Cas, which are known to play key roles in cancer metastasis. Pretreatment with uPAR shRNA expressing construct reduced uPAR and phospho FAK expression levels in pre-established medulloblastoma in nude mice. CONCLUSION/SIGNIFICANCE Taken together, our results show that radiation enhances uPAR-mediated FAK signaling and by targeting uPAR we can inhibit radiation-activated cell adhesion and migration both in vitro and in vivo.
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Affiliation(s)
- Arun Kumar Nalla
- Department of Cancer Biology & Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois, United States of America
| | - Swapna Asuthkar
- Department of Cancer Biology & Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois, United States of America
| | - Praveen Bhoopathi
- Department of Cancer Biology & Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois, United States of America
| | - Meena Gujrati
- Department of Pathology, University of Illinois College of Medicine at Peoria, Peoria, Illinois, United States of America
| | - Dzung H. Dinh
- Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, Illinois, United States of America
| | - Jasti S. Rao
- Department of Cancer Biology & Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois, United States of America
- Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, Illinois, United States of America
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142
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Menda Y, O'Dorisio MS, Kao S, Khanna G, Michael S, Connolly M, Babich J, O'Dorisio T, Bushnell D, Madsen M. Phase I trial of 90Y-DOTATOC therapy in children and young adults with refractory solid tumors that express somatostatin receptors. J Nucl Med 2010; 51:1524-31. [PMID: 20847174 DOI: 10.2967/jnumed.110.075226] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED The purpose of this study was to conduct a phase I trial of (90)Y-DOTATOC to determine the dose-toxicity profile in children and young adults with somatostatin receptor-positive tumors. METHODS A 3 × 3 design was used to determine the highest tolerable dose of (90)Y-DOTATOC, with administered activities of 1.11, 1.48, and 1.85 GBq/m(2)/cycle given in 3 cycles at 6-wk intervals. An amino acid infusion was coadministered with the radiopharmaceutical for renal protection. Eligibility criteria included an age of 2-25 y, progressive disease, a positive lesion on (111)In-diethylenetriaminepentaacetic acid-D-Phe(1)-octreotide scanning, a glomerular filtration rate of 80 mL/min/1.73 m(2) or more, bone marrow cellularity of 40% or more or stored autologous hematopoietic stem cells, 60% or more on the Lansky Play Scale, and informed consent. RESULTS Seventeen subjects (age, 2-24 y) received at least 1 dose of (90)Y-DOTATOC; diagnoses included neuroblastoma, embryonal and astrocytic brain tumors, paraganglioma, multiple endocrine neoplasia IIB, and neuroendocrine tumors. No dose-limiting toxicities and no individual dose reductions due to renal or hematologic toxicity were noted. No complete responses were observed; 2 subjects experienced partial response, 5 had minor responses, 6 experienced stable disease, 2 had progressive disease, and 2 withdrew. CONCLUSION Peptide receptor radionuclide therapy with (90)Y-DOTATOC is safe in children and young adults and demonstrated a 12% partial response plus 29% minor response rate in patients with somatostatin receptor-positive tumors. No dose-limiting toxicities were observed. The recommended phase II dosing is 3 cycles of 1.85 GBq/m(2)/dose of (90)Y-DOTATOC coadministered with amino acids.
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Affiliation(s)
- Yusuf Menda
- Department of Radiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
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143
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MacDonald T. Pediatric Cancer: A Comprehensive Review. Part II: Chemotherapy, Monoclonal Antibodies and Tyrosine Kinase Inhibitors. Can Pharm J (Ott) 2010. [DOI: 10.3821/1913-701x-143.5.240] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Tamara MacDonald
- From the Faculties of Medicine and Health Professions, IWK Health Centre and Dalhousie University, Halifax, NS. Contact
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144
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Coon V, Laukert T, Pedone CA, Laterra J, Kim KJ, Fults DW. Molecular therapy targeting Sonic hedgehog and hepatocyte growth factor signaling in a mouse model of medulloblastoma. Mol Cancer Ther 2010; 9:2627-36. [PMID: 20807782 DOI: 10.1158/1535-7163.mct-10-0486] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The use of genetically engineered mice has provided insights into the molecular pathogenesis of the pediatric brain tumor medulloblastoma and revealed promising therapeutic targets. Ectopic expression of Sonic hedgehog (Shh) in cerebellar neural progenitor cells induces medulloblastomas in mice, and coexpression of hepatocyte growth factor (HGF) enhances Shh-induced tumor formation. To determine whether Shh + HGF-driven medulloblastomas were responsive to Shh signaling blockade and whether treatment response could be enhanced by combination therapy targeting both HGF and Shh signaling pathways, we carried out a survival study in mice. We induced medulloblastomas by retrovirus-mediated expression of Shh and HGF, after which we treated the mice systemically with (a) HGF-neutralizing monoclonal antibody L2G7, (b) Shh signaling inhibitor cyclopamine, (c) Shh-neutralizing monoclonal antibody 5E1, (d) L2G7 + cyclopamine, or (e) L2G7 + 5E1. We report that monotherapy targeting either HGF signaling or Shh signaling prolonged survival and that anti-HGF therapy had a more durable response than Shh-targeted therapy. The effect of L2G7 + 5E1 combination therapy on cumulative survival was equivalent to that of L2G7 monotherapy and that of L2G7 + cyclopamine therapy was worse. The principal mechanism by which Shh- and HGF-targeted therapies inhibited tumor growth was a potent apoptotic death response in tumor cells, supplemented by a weaker suppressive effect on proliferation. Our observation that combination therapy either failed to improve or even reduced survival in mice bearing Shh + HGF-induced medulloblastomas compared with monotherapy underscores the importance of preclinical testing of molecular-targeted therapies in animal models of tumors in which the targeted pathways are known to be active.
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Affiliation(s)
- Valerie Coon
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah 84132, USA
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Heretsch P, Tzagkaroulaki L, Giannis A. Cyclopamine and hedgehog signaling: chemistry, biology, medical perspectives. Angew Chem Int Ed Engl 2010; 49:3418-27. [PMID: 20429080 DOI: 10.1002/anie.200906967] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
When Odysseus left the devastated city of Troy after ten years of siege he could not foresee the perils he still had to face. The encounter with the cyclops, a giant with only one eye placed in the middle of its forehead, was doubtlessly one of the creepiest and most dangerous of his adventures. In the end, Odysseus could only escape with the help of a sheep. Whether Homers cyclops was inspired by the observation of terribly malformed neonates remains speculative. However, when sheep herders in Idaho in the middle of the 20th century faced an increasing number of cyclops-like sheep in their herds, a unique cascade of chemical, biological, and medicinal discoveries was initiated. This Minireview tells this story and shows its impact on modern biomedical research.
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Affiliation(s)
- Philipp Heretsch
- Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
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146
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Onvani S, Etame AB, Smith CA, Rutka JT. Genetics of medulloblastoma: clues for novel therapies. Expert Rev Neurother 2010; 10:811-23. [PMID: 20420498 DOI: 10.1586/ern.10.31] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Medulloblastoma is the most common malignant brain tumor in children. Current medulloblastoma therapy entails surgery, radiation and chemotherapy. The 5-year survival rate for patients ranges from 40 to 70%, with most survivors suffering from serious long-term treatment-related sequelae. Additional research on the molecular biology and genetics of medulloblastoma is needed to identify robust prognostic markers for disease-risk stratification, to improve current treatment regimes and to discover novel and more effective molecular-targeted therapies. Recent advances in molecular biology have led to the development of powerful tools for the study of medulloblastoma tumorigenesis, which have revealed new insights into the molecular underpinnings of this disease. Here we discuss the signaling pathway alterations implicated in medulloblastoma pathogenesis, the techniques used in molecular profiling of these tumors and recent molecular subclassification schemes. Particular emphasis is given to the identification of novel molecular targets for less toxic, patient-tailored therapeutic approaches.
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Affiliation(s)
- Sara Onvani
- The Hospital for Sick Children, Ontario, Canada
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147
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Ohshima-Hosoyama S, Hosoyama T, Nelon LD, Keller C. IGF-1 receptor inhibition by picropodophyllin in medulloblastoma. Biochem Biophys Res Commun 2010; 399:727-32. [PMID: 20692232 DOI: 10.1016/j.bbrc.2010.08.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2010] [Accepted: 08/03/2010] [Indexed: 11/16/2022]
Abstract
The insulin-like growth factor-1 receptor (Igf1r) is a multifunctional membrane-associated tyrosine kinase associated with regulation of transformation, proliferation, differentiation and apoptosis. Increased IGF pathway activity has been reported in human and murine medulloblastoma. Tumors from our genetically-engineered medulloblastoma mouse model over-express Igf1r, and thus this mouse model is a good platform with which to study the role of Igf1r in tumor progression. We hypothesize that inhibition of IGF pathway in medulloblastoma can slow or inhibit tumor growth and metastasis. To test our hypothesis, we tested the role of IGF in tumor growth in vitro by treatment with the tyrosine kinase small molecule inhibitor, picropodophyllin (PPP), which strongly inhibits the IGF pathway. Our results demonstrate that PPP-mediated downregulation of the IGF pathway inhibits mouse tumor cell growth and induces apoptotic cell death in vitro in primary medulloblastoma cultures that are most reflective of tumor cell behavior in vivo.
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Affiliation(s)
- Sachiko Ohshima-Hosoyama
- Greehey Children's Cancer Research Institute, University of Texas Health Science Center, San Antonio, TX 78229, USA
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148
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Heretsch P, Tzagkaroulaki L, Giannis A. Modulators of the hedgehog signaling pathway. Bioorg Med Chem 2010; 18:6613-24. [PMID: 20708941 DOI: 10.1016/j.bmc.2010.07.038] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 07/14/2010] [Accepted: 07/15/2010] [Indexed: 12/12/2022]
Abstract
Since its discovery by C. Nüsslein-Volhard and E. F. Wieschaus, hedgehog (hh) signaling has come a long way. Today it is regarded as a key regulator in embryogenesis where it governs processes like cell proliferation, differentiation, and tissue patterning. Furthermore, in adults it is involved in the maintenance of stem cells, and in tissue repair and regeneration. But hh signaling has a second-much darker-face: it plays an important role in several types of human cancers where it promotes growth and enables proliferation of tumor stem cells. The etiology of medulloblastoma and basal cell carcinoma is tightly linked to aberrant hh activity, but also cancers of the prostate, the pancreas, the colon, the breasts, rhabdomyosarcoma, and leukemia, are dependent on irregular hh activity. Recent clinical studies have shown that hh signaling can be the basis of an important new class of therapeutic agents with far-reaching implications in oncology. Thus, modulation of hh signaling by means of small molecules has emerged as a valuable tool in combating these hh-dependent cancers. Cyclopamine, a unique natural product with a fascinating history, was the first identified inhibitor of hh signaling and its story is closely linked to the progress in the whole field. In this review we will trace the story of cyclopamine, give an overview on the biological modes of hh signaling both in untransformed and malignant cells, and finally present potent modulators of the hh pathway-many of them already in clinical studies. For more than 30 years now the knowledge on hh signaling has grown steadily-an end to this development is far from being conceivable.
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Affiliation(s)
- Philipp Heretsch
- Institut for Organische Chemie, Universität Leipzig, Leipzig, Germany
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149
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Zitterbart K, Filkova H, Tomasikova L, Necesalova E, Zambo I, Kantorova D, Slamova I, Vranova V, Zezulkova D, Pesakova M, Pavelka Z, Veselska R, Kuglik P, Sterba J. Low-level copy number changes of MYC genes have a prognostic impact in medulloblastoma. J Neurooncol 2010; 102:25-33. [PMID: 20607354 DOI: 10.1007/s11060-010-0289-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 06/21/2010] [Indexed: 01/22/2023]
Abstract
High-level amplifications of MYC genes are associated with poor outcomes in childhood medulloblastoma (MB). However, the occurrence of MYCN and MYCC copy number increases below the intense amplification pattern is rarely reported, and its clinical impact has not yet been determined. Here, we describe this phenomenon and its prognostic significance in a cohort of 29 MB patients. Using interphase fluorescence in situ hybridization (I-FISH), low-level copy number alterations, i.e. gain of MYCN, were shown in 5/27 (19%) samples, whereas amplification was revealed in only 1/27 (4%) samples. MYCC gain was revealed in 6/29 (21%) MB, while amplification was disclosed in only 2/29 (7%). Hyperploidy and co-incidence of gains in both MYC loci were frequently observed in samples with copy number aberrations. Survival analysis has clearly shown that MYC copy number increases are associated with lowered event-free survival and overall survival in MB. In the case of MYCN, this negative correlation was statistically significant. We conclude that limited numerical alterations in loci 2p24 (MYCN) and 8q24 (MYCC), as assessed by I-FISH, are present in MB with a higher frequency than high-level amplifications. Poor prognoses were observed in patients with copy number increases in MYC genes. Our data illustrate the importance of further investigations in multicenter trials to better refine the emerging genomic-based prognostic stratification in MB.
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Affiliation(s)
- Karel Zitterbart
- Department of Pediatric Oncology, University Hospital Brno, Masaryk University, Cernopolni 9, 613 00 Brno, Czech Republic.
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150
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Medulloblastoma: atypical CT and MRI findings in children. Pediatr Radiol 2010; 40:1254-62. [PMID: 20386894 DOI: 10.1007/s00247-009-1429-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 09/12/2009] [Accepted: 09/24/2009] [Indexed: 10/19/2022]
Abstract
Posterior fossa mass lesions in children usually present a diagnostic challenge despite their high frequency and the limited number of differential diagnostic possibilities. Consideration of medulloblastoma within the differential diagnosis of such lesions mandates an aggressive surgical approach as residual tumor is a known risk factor for poor prognosis. Preoperative imaging of the entire neuroaxis is critical given the high propensity of drop metastases. In this pictorial presentation, we review and demonstrate less common features of medulloblastomas to facilitate diagnosis in challenging cases.
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