Modeling pediatric medulloblastoma.
Ontology highlight
ABSTRACT:
SUBMITTER: Roussel MF
PROVIDER: S-EPMC7317774 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Medulloblastoma is the most common malignant brain tumor affecting children. These tumors are high grade with propensity to metastasize within the central nervous system and, less frequently, outside the neuraxis. Recent advancements in molecular subgrouping of medulloblastoma refine diagnosis and improve counseling in regards to overall prognosis. Both are predicated on the molecular drivers of each subgroup-WNT-activated, SHH-activated, group 3, and group 4. The traditional therapeutic mainstay for medulloblastoma includes a multimodal approach with surgery, radiation, and multiagent chemotherapy. As we discover more about the molecular basis of medulloblastoma, efforts to adjust treatment approaches based on molecular risk stratification are under active investigation. Certainly, the known neurological, developmental, endocrine, and psychosocial injury related to medulloblastoma and its associated therapies motivate ongoing research towards improving treatment for this life-threatening tumor while at the same time minimizing long-term side effects.
| S-EPMC5909805 | biostudies-literature
Project description:Epigenetics is the process by which gene expression is regulated by events other than alterations of the genome. This includes DNA methylation, histone modifications, chromatin remodeling, microRNAs, and long non-coding RNAs. Methylation of DNA, chromatin remodeling, and histone modifications regulate the chromatin and access of transcription factors to DNA and in turn gene transcription. Alteration of chromatin is now recognized to be deregulated in many cancers. Medulloblastoma is an embryonal tumor of the cerebellum and the most common malignant brain tumor in children, that occurs only rarely in adults. Medulloblastoma is characterized by four major molecularly and histopathologically distinct groups, wingless (WNT), sonic hedgehog (SHH), group 3 (G3), and group 4 (G4), that, except for WNT, are each now subdivided in several subgroups. Gene expression array, next-generation sequencing, and methylation profiling of several hundred primary tumors by several consortia and independent groups revealed that medulloblastomas harbor a paucity of mutations most of which occur in epigenetic regulators, genetic alterations in oncogenes and tumor suppressors, in addition to copy number alterations and chromosome gains and losses. Remarkably, some tumors have no reported mutations, suggesting that some genes required for oncogenesis might be regulated by epigenetic mechanisms which are still to be uncovered and validated. This review will highlight several epigenetic regulators focusing mainly on histone modifiers identified in medulloblastoma.
| S-EPMC5807456 | biostudies-literature
Project description:Medulloblastoma (MB) is one of the most common malignant pediatric brain tumor. The aim of our study was to understand which mechanisms are involved in aberrant activation of Wnt pathway and its association with MB tumor development. We studied the expression profiles of 19 MBs tumors using a genome-wide approach, furthermore we have included the data obtained from four independent public Datasets of gene expression (see README file below) to increase the statistical power of the study. The expression profiles identified the Wnt inhibitor gene, DKK3, significant down-regulated. DKK3 down-regulation was confirmed by qPCR in 80% of samples (27/33 MB tumors and in 3/5 MB human cell lines). Since DKK3 was found methylated in several cancers we also investigated the status of methylated CpG sites within the three promoters by a combination of two approaches: the MSP and pyrosequencing. MSP showed no methylation in all promoters while the pyrosequencing, a quantitative technique, indicated a very low level of methylation. To verify the epigenetic involvement on DKK3 silencing, we also studied the effect of Trichostatin A (TSA) in 4 MB cell lines (DAOY; D283; D425; D458). After TSA treatment we observed a significant DKK3 mRNA expression increase in 3/4 cell lines compared to the no treated cells. DAOY cells, that have a normal DKK3 expression value, did not change significantly the DKK3 expression after TSA treatment. To further validate the role of histone tail modifications as an epigenetic silencing mechanism for DKK3 in MB, we performed Chromatin Immunoprecipitation (ChIP) experiment using antibodies against acetylated histones. According to our earlier results, TSA treatment increased the signal of the histone modification meH3K4 which is related to a transcriptionally active gene respect to the untreated controls. Finally, we evaluated the DKK3 protein in three MB cell lines (DAOY; D283; D425) after 24h of TSA treatment, by immunofluorescence. We analysed 19 Medulloblastoma tumor from pediatric patients, a commercial pool (Clontech) of 24 normal cerebellum from female and male Caucasians (ages: 16-70 years; cause of death: sudden death) and a pool of 10 normal cerebellum from children (6 Caucasians and 4 African Americans; ages: 0-16 years; cause of death: sudden death) using 44K whole genome oligonucleotids microarray
| S-ECPF-GEOD-39182 | biostudies-other
Project description:Whole-genome screening of CpG Island methylation status by array-based profiling of absolute methylation status (array-PAMS). Methylation-specifically digested DNA (Cy3) was hybridized against methylation-sensitively digested DNA (Cy5) from the same sample. CGI methylation in 20 pediatric medulloblastomas (M) and normal cerebellum (Cb, pool of five unaffected donors, age 25â33 years)
2010-06-30 | E-GEOD-4857 | biostudies-arrayexpress
Project description:Whole-genome screening of CpG Island methylation status by array-based profiling of absolute methylation status (array-PAMS). Keywords: methylation profiling, pediatric medulloblastoma, single sample
2007-07-31 | GSE4857 | GEO
Project description:Medulloblastoma is one of the most frequent among pediatric brain tumors, and it has been classified in various subgroups. Some of them already benefit from quite good therapeutic options, whereas others urgently need novel therapeutic approaches. Epigenetic modulators have long been studied in various types of cancer. Within this review, we summarize the main preclinical studies regarding epigenetic targets (such as HDAC, SIRT, BET, EZH2, G9a, LSD1, and DNMT) inhibitors in medulloblastoma. Furthermore, we shed light on the increasing number of applications of drug combinations as well as hybrid compounds involving epigenetic mechanisms. Nevertheless, in the studies published so far, mainly un-specific or old modulators have been used, and the PKs (brain permeability) have not been well-evaluated. Thus, these findings should be considered as a starting point for further improvement and not as a final result.
| S-EPMC6286966 | biostudies-literature
Project description:Background/aimMedulloblastoma (MBL), an archetypal primitive neuroectodermal tumor of the cerebellum, is the most common pediatric central nervous system malignancy representing approximately 20% of all childhood brain tumors. Herein, we report on a new xenotransplantable tumor cell line, derived from a 6-year-old female patient with cerebellar medulloblastoma, and the completele proteome molecular characterization of subsequent tumors from MBL xenotrasplanted mice.Materials and methodsTumors were grown in nude mice as subcutaneous xenografts (MBLX) composed of small round cells with hyperchromatic nuclei and scant cytoplasm. Tumor specimen were extracted from animals upon their sacrifice and their molecular proteomic content was analyzed by 2-DE coupled to MALDI-TOF MS analysis.ResultsAltogether 350 single-gene products were identified through the current approach, reported as the MBLX database.ConclusionThis new xenotransplantable tumor model, offers the scientific community valuable insight on the validity of xenografts altogether, while providing the means for a novel experimental model towards the study of human MBL.
| S-EPMC5572304 | biostudies-literature
Project description:BackgroundMedulloblastoma (MB) is one of the most common malignant cancers in children. MB is primarily classified into four subgroups based on molecular and clinical characteristics as (1) WNT (2) Sonic-hedgehog (SHH) (3) Group 3 (4) Group 4. Molecular characteristics used for MB classification are based on genomic and mRNAs profiles. MB subgroups share genomic and mRNA profiles and require multiple molecular markers for differentiation from each other. Long non-coding RNAs (lncRNAs) are more than 200 nucleotide long RNAs and primarily involve in gene regulation at epigenetic and post-transcriptional levels. LncRNAs have been recognized as diagnostic and prognostic markers in several cancers. However, the lncRNA expression profile of MB is unknown.MethodsWe used the publicly available gene expression datasets for the profiling of lncRNA expression across MB subgroups. Functional analysis of differentially expressed lncRNAs was accomplished by Ingenuity pathway analysis (IPA).ResultsIn the current study, we have identified and validated the lncRNA expression profile across pediatric MB subgroups and associated molecular pathways. We have also identified the prognostic significance of lncRNAs and unique lncRNAs associated with each MB subgroup.ConclusionsIdentified lncRNAs can be used as single biomarkers for molecular identification of MB subgroups that warrant further investigation and functional validation.
| S-EPMC7318516 | biostudies-literature
Project description:The main cause of death in medulloblastoma is recurrence associated with leptomeningeal dissemination. Although the molecular basis of medulloblastoma has received considerable attention over the past decade, the role of microRNAs (miRNAs) in the acquisition of metastatic phenotype remains poorly understood. This study aimed to identify miRNA involved in leptomeningeal dissemination and to elucidate its target mechanisms. We analyzed miRNA expression profiles of 29 medulloblastomas according to the presence of cerebrospinal fluid (CSF) seeding. The differential expressed miRNAs (DEmiRNAs) were validated on 29 medulloblastoma tissues and three medulloblastoma cells. The biological function of the selected miRNA was evaluated using in vitro studies. A total of 12 DEmiRNAs were identified including miRNA-192 in medulloblastoma with seeding. The reduced expression of miRNA-192 was confirmed in tumor seeding group and the medulloblastoma cells. Overexpression of miRNA-192 inhibited cellular proliferation targeting dihydrofolate reductase (DHFR). MiRNA-192 decreased cellular anchoring via repression of integrin subunits (αV, β1, and β3) and CD47. Medulloblastoma with seeding showed specific DEmiRNAs compared with those without seeding. MicroRNA-192 suppresses leptomeningeal dissemination of medulloblastoma through modulating cell proliferation and anchoring ability. leptomeningeal dissemination in 29 pediatric medulloblastoma patients
2015-12-31 | E-GEOD-66968 | biostudies-arrayexpress
Project description:PurposeMedulloblastoma is the most common malignant brain tumor occurring in childhood and is a significant cause of morbidity and mortality in pediatric oncology. More intense treatment strategies are recommended for patients displaying high-risk factors; however, considerable variation in outcome remains, indicating a need for improved predictive markers. In this study, 1H magnetic resonance spectroscopy (MRS) was used to investigate noninvasive molecular biomarkers of survival in medulloblastoma.Experimental designMRS was performed on a series of 35 biopsy-confirmed medulloblastoma cases. One case was excluded because of poor quality MRS. The prognostic value of MRS detectable biomarkers was investigated using Cox regression, retrospectively (N=15). A subsequent validation analysis (N=19) was also performed to reduce the chance of type I errors. Where available, high-resolution ex vivo MRS of biopsy tissue was used to confirm biomarker assignments.ResultsThe retrospective analysis revealed that creatine, glutamate, and glycine were markers of survival (P<0.01). The validation analysis showed that glutamate was a robust marker, with a hazard ration (HR) of 8.0 for the full dataset (P=0.0003, N=34). A good correlation between in vivo and ex vivo MRS glutamate/total-choline was found (P=0.001), validating the in vivo assignment. Ex vivo glutamate/total-choline was also associated with survival (P<0.01).ConclusionThe identification of glutamate as a predictive biomarker of survival in pediatric medulloblastoma provides a clinically viable risk factor and highlights the importance of more detailed studies into the metabolism of this disease. Noninvasive biomarker detection using MRS may offer improved disease monitoring and potential for widespread use following multicenter validation.
| S-EPMC4154860 | biostudies-literature