Abstract
BackgroundMedulloblastoma (MB) is an aggressive pediatric tumor of the Central Nervous System (CNS) usually treated according to a refined risk stratification. The study of cancer stem cells (CSC) in MB is a promising approach aimed at finding new treatment strategies.Methodology/Principal FindingsThe CSC compartment was studied in three characterized MB cell lines (DAOY, UW228 and ONS-76) grown in standard adhesion as well as being grown as spheres, which enables expansion of the CSC population. MB cell lines, grown in adherence and as spheres, were subjected to morphologic analysis at the light and electron microscopic level, as well as cytofluorimetric determinations. Medullospheres (MBS) were shown to express increasingly immature features, along with the stem cells markers: CD133, Nestin and β-catenin. Proteomic analysis highlighted the differences between MB cell lines, demonstrating a unique protein profile for each cell line, and minor differences when grown as spheres. In MBS, MALDI-TOF also identified some proteins, that have been linked to tumor progression and resistance, such as Nucleophosmin (NPM). In addition, immunocytochemistry detected Sox-2 as a stemness marker of MBS, as well as confirming high NPM expression.Conclusions/SignificanceCulture conditioning based on low attachment flasks and specialized medium may provide new data on the staminal compartment of CNS tumors, although a proteomic profile of CSC is still elusive for MB.
Highlights
Medulloblastoma (MB) is an aggressive pediatric tumor of the cerebellum with ‘‘embryonal’’ features and early leptomeningeal spreading.A dramatic increase in crude survival has been associated with relevant toxicity as a result of chemotherapy and/or radiation therapy effects on the developing brain.A wealth of new data, from the new pathological classification [1] to genetic studies based on gene expression and Comparative Genomic Hybridization [2], as well as Proteomics [3], has permitted the identification of molecular subgroups with different gene expression profiles and protein expression
UW228 and ONS-76 showed a different trend, with the number of spheres decreasing from the second passage onwards (Fig. 1B)
Morphological and molecular heterogeneity of this malignant childhood brain tumor has been deeply investigated, and activation of gene and protein expression may allow molecular sub-grouping and dissection of the signaling pathways involved in tumor growth and progression [2,3]
Summary
Medulloblastoma (MB) is an aggressive pediatric tumor of the cerebellum with ‘‘embryonal’’ features and early leptomeningeal spreading.A dramatic increase in crude survival has been associated with relevant toxicity as a result of chemotherapy and/or radiation therapy effects on the developing brain.A wealth of new data, from the new pathological classification [1] to genetic studies based on gene expression and Comparative Genomic Hybridization [2], as well as Proteomics [3], has permitted the identification of molecular subgroups with different gene expression profiles and protein expression. A therapeutic approach based on the risk stratification of patients may ensure a better quality of life to children that are treated in order to avoid over-treatment. A better understanding of the role of Cancer Stem Cells (CSC), (recently referred as brain tumor-initiating cells) may be of peculiar interest in MB, a tumor with relevant molecular heterogeneity [4]. Nestin and SOX-2 play a role in neurogenesis and are considered to be markers of neural stem cells in brain development [12]. Medulloblastoma (MB) is an aggressive pediatric tumor of the Central Nervous System (CNS) usually treated according to a refined risk stratification. The study of cancer stem cells (CSC) in MB is a promising approach aimed at finding new treatment strategies
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