Medulloblastoma: Molecular Classification-Based Personal Therapeutics

miR-124-3p and miR-194-5p regulation of the PI3K/AKT pathway via ROR2 in medulloblastoma progression

Medulloblastoma (MB), a prevalent pediatric central nervous system tumor, is influenced by microRNAs (miRNAs) that impact tumor initiation and progression. However, the specific involvement of miRNAs in MB tumorigenesis remains unclear. Using single-cell RNA sequencing, we identified ROR2 expression in normal human fetal cerebellum. Subsequent analyses, including immunofluorescence, quantitative real-time PCR (qRT-PCR), and Western blot, assessed ROR2 expression in MB tissues and cell lines. We investigated miR-124-3p and miR-194-5p and their regulatory role in ROR2 expression through the dual-luciferase reporter, qRT-PCR, and western blot assays. Mechanistic insights were gained through functional assays exploring the impact of miR-124-3p, miR-194-5p, and ROR2 on MB growth in vitro and in vivo. We observed significantly reduced miR-124-3p and miR-194-5p expression and elevated ROR2 expression in MB tissues and cell lines. High ROR2 expression inversely correlated with overall survival in WNT and SHH subgroups of MB patients. Functionally, overexpressing miR-124-3p and miR-194-5p and inhibiting ROR2 suppressed in vitro malignant transformation and in vivo tumorigenicity. Mechanistically, miR-124-3p and miR-194-5p synergistically regulated the ROR2/PI3K/Akt pathway, influencing MB progression. Our findings indicate that miR-124-3p and miR-194-5p function as tumor suppressors, inhibiting MB progression via the ROR2/PI3K/Akt axis, suggesting a key mechanism and therapeutic targets for MB patients.

Preclinical assessment of MAGMAS inhibitor as a potential therapy for pediatric medulloblastoma

Medulloblastoma, the most common pediatric brain malignancy, has Sonic Hedgehog (SHH) and non-SHH group3 subtypes. MAGMAS (Mitochondrial Associated Granulocyte Macrophage colony-stimulating factor Signaling molecules) encode for mitochondrial import inner membrane translocase subunit and is responsible for translocation of matrix proteins across the inner membrane. We previously reported that a small molecule MAGMAS inhibitor, BT9, decreases cell proliferation, migration, and oxidative phosphorylation in adult glioblastoma cell lines. The aim of our study was to investigate whether the chemotherapeutic effect of BT9 can be extended to pediatric medulloblastoma.

Methods

Multiple in vitro assays were performed using human DAOY (SHH activated tp53 mutant) and D425 (non-SHH group 3) cells. The impact of BT9 on cellular growth, death, migration, invasion, and metabolic activity were quantified using MTT assay, TUNEL staining, scratch wound assay, Matrigel invasion chambers, and seahorse assay, respectively. Survival following 50mg/kg BT9 treatment was assessed in vivo in immunodeficient mice intracranially implanted with D425 cells.

Results

Compared to control, BT9 treatment led to a significant reduction in medulloblastoma cell growth (DAOY, 24hrs IC50: 3.6uM, 48hrs IC50: 2.3uM, 72hrs IC50: 2.1uM; D425 24hrs IC50: 3.4uM, 48hrs IC50: 2.2uM, 72hrs IC50: 2.1uM) and a significant increase in cell death (DAOY, 24hrs p=0.0004, 48hrs p<0.0001; D425, 24hrs p=0.0001, 48hrs p=0.02). In DAOY cells, 3uM BT9 delayed migration, and significantly decreased DAOY and D425 cells invasion (p < 0.0001). Our in vivo study, however, did not extend survival in xenograft mouse model of group3 medulloblastoma compared to vehicle-treated controls.

Conclusions

Our in vitro data showed BT9 antitumor efficacy in DAOY and D425 cell lines suggesting that BT9 may represent a promising targeted therapeutic in pediatric medulloblastoma. These data, however, need to be further validated in animal models.

Heterogeneity and tumoral origin of medulloblastoma in the single-cell era

Medulloblastoma is one of the most common malignant pediatric brain tumors derived from posterior fossa. The current treatment includes maximal safe surgical resection, radiotherapy, whole cranio-spinal radiation and adjuvant with chemotherapy. However, it can only limitedly prolong the survival time with severe side effects and relapse. Defining the intratumoral heterogeneity, cellular origin and identifying the interaction network within tumor microenvironment are helpful for understanding the mechanisms of medulloblastoma tumorigenesis and relapse. Due to technological limitations, the mechanisms of cellular heterogeneity and tumor origin have not been fully understood. Recently, the emergence of single-cell technology has provided a powerful tool for achieving the goal of understanding the mechanisms of tumorigenesis. Several studies have demonstrated the intratumoral heterogeneity and tumor origin for each subtype of medulloblastoma utilizing the single-cell RNA-seq, which has not been uncovered before using conventional technologies. In this review, we present an overview of the current progress in understanding of cellular heterogeneity and tumor origin of medulloblastoma and discuss novel findings in the age of single-cell technologies.

Development and validation of a 23-gene expression signature for molecular subtyping of medulloblastoma in a long-term Chinese cohort

PURPOSE

Medulloblastoma is the most common childhood malignant brain tumor and is a leading cause of cancer-related death in children. Recent transcriptional studies have shown that medulloblastomas comprise at least four molecular subgroups, each with distinct demographics, genetics, and clinical outcomes. Medulloblastoma subtyping has become critical for subgroup-specific therapies. The use of gene expression assays to determine the molecular subgroup of clinical specimens is a long-awaited application of molecular biology for this pediatric cancer.

METHODS

In the current study, we established a medulloblastoma transcriptome database of 460 samples retrieved from three published datasets (GSE21140, GSE37382, and GSE37418). With this database, we identified a 23-gene signature that is significantly associated with the medulloblastoma subgroups and achieved a classification accuracy of 95.2%.

RESULTS

The 23-gene signature was further validated in a long-term cohort of 142 Chinese medulloblastoma patients. The 23-gene signature classified 21 patients as WNT (15%), 41 as SHH (29%), 16 as Group 3 (11%), and 64 as Group 4 (45%). For patients of WNT, SHH, Group 3, and Group 4, 5-year overall-survival rate reached 80%, 62%, 27%, and 47%, respectively (p < 0.0001), meanwhile 5-year progression-free survival reached 80%, 52%, 27%, and 45%, respectively (p < 0.0001). Besides, SHH/TP53-mutant tumors were associated with worse prognosis compared with SHH/TP53 wild-type tumors and other subgroups. We demonstrated that subgroup assignments by the 23-gene signature and Northcott's NanoString assay were highly comparable with a concordance rate of 96.4%.

CONCLUSIONS

In conclusion, we present a novel gene signature that is capable of accurately and reliably assigning FFPE medulloblastoma samples to their molecular subgroup, which may serve as an auxiliary tool for medulloblastoma subtyping in the clinic. Future incorporation of this gene signature into prospective clinical trials is warranted to further evaluate its clinical.

Survival nomogram for medulloblastoma and multi-center external validation cohort

Background: Medulloblastoma (MB) is a highly malignant neuroepithelial tumor occurring in the central nervous system. The objective of this study was to establish an effective prognostic nomogram to predict the overall survival (OS) of MB patients. Materials and methods: The nomogram was developed using data from a retrospective cohort of 280 medulloblastoma patients (aged 3-18 years) identified from Beijing Tiantan Hospital between 2016 and 2021 as the training cohort. To validate the performance of the nomogram, collaborations were formed with eight leading pediatric oncology centers across different regions of China. A total of 162 medulloblastoma patients meeting the inclusion criteria were enrolled from these collaborating centers. Cox regression analysis, best subsets regression, and Lasso regression were employed to select independent prognostic factors. The nomogram's prognostic effectiveness for overall survival was assessed using the concordance index, receiver operating characteristic curve, and calibration curve. Results: In the training cohort, the selected variables through COX regression, best subsets regression, and Lasso regression, along with their clinical significance, included age, molecular subtype, histological type, radiotherapy, chemotherapy, metastasis, and hydrocephalus. The internally and externally validated C-indexes were 0.907 and 0.793, respectively. Calibration curves demonstrated the precise prediction of 1-, 3-, and 5-year OS for MB patients using the nomogram. Conclusion: This study developed a nomogram that incorporates clinical and molecular factors to predict OS prognosis in medulloblastoma patients. The nomogram exhibited improved predictive accuracy compared to previous studies and demonstrated good performance in the external validation cohort. By considering multiple factors, clinicians can utilize this nomogram as a valuable tool for individualized prognosis prediction and treatment decision-making in medulloblastoma patients.

Capturing evolving definitions of 12 select rare CNS tumors: a timely report from CBTRUS and NCI-CONNECT

PURPOSE

Incidence, prevalence, and survival are population-based statistics describing cancer burden. The National Cancer Institute's (NCI) Comprehensive Oncology Network Evaluating Rare CNS Tumors (NCI-CONNECT) specializes in tumor biology and outcomes for 12 rare CNS tumor types selected for their importance in adults, research interest, or potential for targeted treatment. The aim of this study was to update incidence, prevalence, and survival statistics for these tumors.

METHODS

The Central Brain Tumor Registry of the United States (CBTRUS) database, a combined dataset of Centers for Disease Control and Prevention's (CDC) National Program of Cancer Registries (NPCR) and NCI's Surveillance, Epidemiology and End Results (SEER) data, was used to calculate average annual age-adjusted incidence rates (AAAIR) per 100,000 population overall and by sex, race-ethnicity, and age for diagnosis years 2008-2019. Incidence time trends were calculated for diagnosis years 2004-2019. NPCR data were used to calculate relative survival rates. Point prevalence on December 31, 2019 was estimated using annual age-specific incidence and survival.

RESULTS

AAAIR was 1.47 per 100,000 for these tumors combined, with highest incidence in ependymomas (AAAIR = 0.41/100,000). Most tumor types were more common in males, adults (ages 40 + years) or children (ages < 15 years), and non-Hispanic White individuals. Ependymomas were the most prevalent tumor type (19,320 cases) followed by oligodendrogliomas (14,900 cases). Ependymomas had the highest five-year survival (90.6%) and primary CNS sarcomas the lowest (7.7%).

CONCLUSIONS

These data provide means to measure the impact of clinical care and evaluate new therapies and the evolving histopathology definitions in rare CNS tumor types.

Lysine-specific demethylase 7A (KDM7A): A potential target for disease therapy

Histone demethylation is a kind of epigenetic modification mediated by a variety of enzymes and participates in regulating multiple physiological and pathological events. Lysine-specific demethylase 7A is a kind of α-ketoglutarate- and Fe(II)-dependent demethylase belonging to the PHF2/8 subfamily of the JmjC demethylases. KDM7A is mainly localized in the nucleus and contributes to transcriptional activation via removing mono- and di-methyl groups from the lysine residues 9 and 27 of Histone H3. Mounting studies support that KDM7A is not only necessary for normal embryonic, neural, and skeletal development, but also associated with cancer, inflammation, osteoporosis, and other diseases. Herein, the structure of KDM7A is described by comparing the similarities and differences of its amino acid sequences of KDM7A and other Histone demethylases; the functions of KDM7A in homeostasis and dyshomeostasis are summarized via documenting its content and related signaling; the currently known KDM7A-specific inhibitors and their structural relationship are listed based on their structure optimization and pharmacological activities; and the challenges and opportunities in exploring functions and developing targeted agents of KDM7A are also prospected via presenting encountered problems and potential solutions, which will provide an insight in functional exploration and drug discovery for KDM7A-related diseases.

The role of chromatin remodeler SMARCA4/BRG1 in brain cancers: a potential therapeutic target

The chromatin remodeler SMARCA4/BRG1 is a key epigenetic regulator with diverse roles in coordinating the molecular programs that underlie brain tumour development. BRG1 function in brain cancer is largely specific to the tumour type and varies further between tumour subtypes, highlighting its complexity. Altered SMARCA4 expression has been linked to medulloblastoma, low-grade gliomas such as oligodendroglioma, high-grade gliomas such as glioblastoma and atypical/teratoid rhabdoid tumours. SMARCA4 mutations in brain cancer predominantly occur in the crucial catalytic ATPase domain, which is associated with tumour suppressor activity. However, SMARCA4 is opposingly seen to promote tumourigenesis in the absence of mutation and through overexpression in other brain tumours. This review explores the multifaceted interaction between SMARCA4 and various brain cancer types, highlighting its roles in tumour pathogenesis, the pathways it regulates, and the advances that have been made in understanding the functional relevance of mutations. We discuss developments made in targeting SMARCA4 and the potential to translate these to adjuvant therapies able to enhance current methods of brain cancer treatment.

Radiomics-based machine learning models for prediction of medulloblastoma subgroups: a systematic review and meta-analysis of the diagnostic test performance

BACKGROUND

Medulloblastomas are a major cause of cancer-related mortality in the pediatric population. Four molecular groups have been identified, and these molecular groups drive risk stratification, prognostic modeling, and the development of novel treatment modalities. It has been demonstrated that radiomics-based machine learning (ML) models are effective at predicting the diagnosis, molecular class, and grades of CNS tumors.

PURPOSE

To assess radiomics-based ML models' diagnostic performance in predicting medulloblastoma subgroups and the methodological quality of the studies.

MATERIAL AND METHODS

A comprehensive literature search was performed on PubMed; the last search was conducted on 1 May 2022. Studies that predicted all four medulloblastoma subgroups in patients with histopathologically confirmed medulloblastoma and reporting area under the curve (AUC) values were included in the study. The quality assessments were conducted according to the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and Checklist for Artificial Intelligence in Medical Imaging (CLAIM). A meta-analysis of radiomics-based ML studies' diagnostic performance for the preoperative evaluation of medulloblastoma subgrouping was performed.

RESULTS

Five studies were included in this meta-analysis. Regarding patient selection, two studies indicated an unclear risk of bias according to the QUADAS-2. The five studies had an average CLAIM score and compliance score of 23.2 and 0.57, respectively. The meta-analysis showed pooled AUCs of 0.88, 0.82, 0.83, and 0.88 for WNT, SHH, group 3, and group 4 for classification, respectively.

CONCLUSION

Radiomics-based ML studies have good classification performance in predicting medulloblastoma subgroups, with AUCs >0.80 in every subgroup. To be applied to clinical practice, they need methodological quality improvement and stability.

IGFBP2 promotes proliferation and cell migration through STAT3 signaling in Sonic hedgehog medulloblastoma

Medulloblastoma (MB) is the most common pediatric brain malignancy and is divided into four molecularly distinct subgroups: WNT, Sonic Hedgehog (SHHp53mut and SHHp53wt), Group 3, and Group 4. Previous reports suggest that SHH MB features a unique tumor microenvironment compared with other MB groups. To better understand how SHH MB tumor cells interact with and potentially modify their microenvironment, we performed cytokine array analysis of culture media from freshly isolated MB patient tumor cells, spontaneous SHH MB mouse tumor cells and mouse and human MB cell lines. We found that the SHH MB cells produced elevated levels of IGFBP2 compared to non-SHH MBs. We confirmed these results using ELISA, western blotting, and immunofluorescence staining. IGFBP2 is a pleiotropic member of the IGFBP super-family with secreted and intracellular functions that can modulate tumor cell proliferation, metastasis, and drug resistance, but has been understudied in medulloblastoma. We found that IGFBP2 is required for SHH MB cell proliferation, colony formation, and cell migration, through promoting STAT3 activation and upregulation of epithelial to mesenchymal transition markers; indeed, ectopic STAT3 expression fully compensated for IGFBP2 knockdown in wound healing assays. Taken together, our findings reveal novel roles for IGFBP2 in SHH medulloblastoma growth and metastasis, which is associated with very poor prognosis, and they indicate an IGFBP2-STAT3 axis that could represent a novel therapeutic target in medulloblastoma.

Identification of CD114 Membrane Receptors as a Molecular Target in Medulloblastomas

Medulloblastomas are the most common solid tumors in children, accounting for 8–30% of pediatric brain cancers. It is a high-grade tumor with aggressive behavior and a typically b poor prognosis. Its treatment includes surgery, chemotherapy, and radiotherapy, and presents high morbidity. Significant clinical, genetic, and prognostic differences exist between its four molecular subgroups: WNT, SHH, Group 3, and Group 4. Many studies seek to develop new chemotherapeutic agents for medulloblastomas through the identification of genes whose expressions are new molecular targets for drugs, such as membrane receptors associated with cell replication. This study aimed to assess the association of CD114 expression with mortality in patients with medulloblastoma. Databases from the Medulloblastoma Advanced Genomics International Consortium (MAGIC) were analyzed, focusing on the expression of the CD114 membrane receptor in different molecular types and its possible association with mortality. Our findings showed different CD114 expressions between Group 3 and other molecular groups, as well as between the molecular subtypes SHH γ and Group 3 α and Group 3 β. There was no statistically significant difference between the other groups and subtypes. Regarding mortality, this study did not find statistical significance in the association between low and high CD114 expressions and mortality. Medulloblastoma is a heterogeneous disease with many subtype variations of its genetic and intracellular signaling pathways. Similarly to this study, which could not demonstrate different CD114 membrane receptor expression patterns between groups, others who sought to associate CD114 expression with mortality in other types of cancer failed to establish a direct association. Since many indications point to the relation of this gene with cancer stem cells (CSCs), it may be part of a more extensive cellular signaling pathway with an eventual association with tumor recurrence. This study found no direct relationship between CD114 expression and mortality in patients with medulloblastoma. Further studies are needed on the intracellular signaling pathways associated with this receptor and its gene (the CSF3R).

Infrared Spectroscopy as a Potential Diagnostic Tool for Medulloblastoma

INTRODUCTION

Medulloblastoma (MB) is the most common malignant tumor of the central nervous system in childhood. FTIR spectroscopy provides a holistic view of the chemical composition of biological samples, including the detection of molecules such as nucleic acids, proteins, and lipids. This study evaluated the applicability of FTIR spectroscopy as a potential diagnostic tool for MB.

MATERIALS AND METHODS

FTIR spectra of MB samples from 40 children (boys/girls: 31/9; age: median 7.8 years, range 1.5-21.5 years) treated in the Oncology Department of the Children's Memorial Health Institute in Warsaw between 2010 and 2019 were analyzed. The control group consisted of normal brain tissue taken from four children diagnosed with causes other than cancer. Formalin-fixed and paraffin-embedded tissues were sectioned and used for FTIR spectroscopic analysis. The sections were examined in the mid-infrared range (800-3500 cm^-1) by ATR-FTIR. Spectra were analysed using a combination of principal component analysis, hierarchical cluster analysis, and absorbance dynamics.

RESULTS

FTIR spectra in MB were significantly different from those of normal brain tissue. The most significant differences related to the range of nucleic acids and proteins in the region 800-1800 cm^-1. Some major differences were also revealed in the quantification of protein conformations (α-helices, β-sheets, and others) in the amide I band, as well as in the absorbance dynamics in the 1714-1716 cm^-1 range (nucleic acids). It was not, however, possible to clearly distinguish between the various histological subtypes of MB using FTIR spectroscopy.

CONCLUSIONS

MB and normal brain tissue can be distinguished from one another to some extent using FTIR spectroscopy. As a result, it may be used as a further tool to hasten and enhance histological diagnosis.

Superenhancers as master gene regulators and novel therapeutic targets in brain tumors

Transcriptional deregulation, a cancer cell hallmark, is driven by epigenetic abnormalities in the majority of brain tumors, including adult glioblastoma and pediatric brain tumors. Epigenetic abnormalities can activate epigenetic regulatory elements to regulate the expression of oncogenes. Superenhancers (SEs), identified as novel epigenetic regulatory elements, are clusters of enhancers with cell-type specificity that can drive the aberrant transcription of oncogenes and promote tumor initiation and progression. As gene regulators, SEs are involved in tumorigenesis in a variety of tumors, including brain tumors. SEs are susceptible to inhibition by their key components, such as bromodomain protein 4 and cyclin-dependent kinase 7, providing new opportunities for antitumor therapy. In this review, we summarized the characteristics and identification, unique organizational structures, and activation mechanisms of SEs in tumors, as well as the clinical applications related to SEs in tumor therapy and prognostication. Based on a review of the literature, we discussed the relationship between SEs and different brain tumors and potential therapeutic targets, focusing on glioblastoma.

Preoperative prediction of sonic hedgehog and group 4 molecular subtypes of pediatric medulloblastoma based on radiomics of multiparametric MRI combined with clinical parameters

Purpose

To construct a machine learning model based on radiomics of multiparametric magnetic resonance imaging (MRI) combined with clinical parameters for predicting Sonic Hedgehog (SHH) and Group 4 (G4) molecular subtypes of pediatric medulloblastoma (MB).

Methods

The preoperative MRI images and clinical data of 95 patients with MB were retrospectively analyzed, including 47 cases of SHH subtype and 48 cases of G4 subtype. Radiomic features were extracted from T1-weighted imaging (T1), contrast-enhanced T1 weighted imaging (T1c), T2-weighted imaging (T2), T2 fluid-attenuated inversion recovery imaging (T2FLAIR), and apparent diffusion coefficient (ADC) maps, using variance thresholding, SelectKBest, and Least Absolute Shrinkage and Selection Operator (LASSO) regression algorithms. The optimal features were filtered using LASSO regression, and a logistic regression (LR) algorithm was used to build a machine learning model. The receiver operator characteristic (ROC) curve was plotted to evaluate the prediction accuracy, and verified by its calibration, decision and nomogram. The Delong test was used to compare the differences between different models.

Results

A total of 17 optimal features, with non-redundancy and high correlation, were selected from 7,045 radiomics features, and used to build an LR model. The model showed a classification accuracy with an under the curve (AUC) of 0.960 (95% CI: 0.871-1.000) in the training cohort and 0.751 (95% CI: 0.587-0.915) in the testing cohort, respectively. The location of the tumor, pathological type, and hydrocephalus status of the two subtypes of patients differed significantly (p < 0.05). When combining radiomics features and clinical parameters to construct the combined prediction model, the AUC improved to 0.965 (95% CI: 0.898-1.000) in the training cohort and 0.849 (95% CI: 0.695-1.000) in the testing cohort, respectively. There was a significant difference in the prediction accuracy, as measured by AUC, between the testing cohorts of the two prediction models, which was confirmed by Delong's test (p = 0.0144). Decision curves and nomogram further validate that the combined model can achieve net benefits in clinical work.

Conclusion

The combined prediction model, constructed based on radiomics of multiparametric MRI and clinical parameters can potentially provide a non-invasive clinical approach to predict SHH and G4 molecular subtypes of MB preoperatively.

Radiotherapy-Induced Neurocognitive Dysfunction in Brain Tumor Survivors: Burden and Rehabilitation

Radiotherapy-induced neurocognitive dysfunction after cranial irradiation has an incidence of 40-100%. It may affect both children and adults, and represents a significant burden not only on ill individuals and their caregivers but also on the health care system and society in general. Multiple patient-, tumor-, and treatment-related factors may contribute to development of this complication, but its pathophysiological mechanisms are still not understood clearly. It is hoped that introduction of more advanced techniques for conformal irradiation, optimized dosimetry, and specific prophylactic measures will decrease the risk of neurocognitive decline in brain tumor survivors in the future.

O-GlcNAcylation promotes cerebellum development and medulloblastoma oncogenesis via SHH signaling

Cerebellar development relies on a precise coordination of metabolic signaling, epigenetic signaling, and transcriptional regulation. Here, we reveal that O-GlcNAc transferase (OGT) regulates cerebellar neurogenesis and medulloblastoma growth via a Sonic hedgehog (Shh)-Smo-Gli2 pathway. We identified Gli2 as a substrate of OGT, and unveiled cross-talk between O-GlcNAc and epigenetic signaling as a means to regulate Gli2 transcriptional activity. Moreover, genetic ablation or chemical inhibition of OGT significantly suppresses tumor progression and increases survival in a mouse model of Shh subgroup medulloblastoma. Taken together, the data in our study provide a line of inquiry to decipher the signaling mechanisms underlying cerebellar development, and highlights a potential target to investigate related pathologies, such as medulloblastoma.

Sonic hedgehog (Shh) signaling plays a critical role in regulating cerebellum development by maintaining the physiological proliferation of granule neuron precursors (GNPs), and its dysregulation leads to the oncogenesis of medulloblastoma. O-GlcNAcylation (O-GlcNAc) of proteins is an emerging regulator of brain function that maintains normal development and neuronal circuitry. Here, we demonstrate that O-GlcNAc transferase (OGT) in GNPs mediate the cerebellum development, and the progression of the Shh subgroup of medulloblastoma. Specifically, OGT regulates the neurogenesis of GNPs by activating the Shh signaling pathway via O-GlcNAcylation at S355 of GLI family zinc finger 2 (Gli2), which in turn promotes its deacetylation and transcriptional activity via dissociation from p300, a histone acetyltransferases. Inhibition of OGT via genetic ablation or chemical inhibition improves survival in a medulloblastoma mouse model. These data uncover a critical role for O-GlcNAc signaling in cerebellar development, and pinpoint a potential therapeutic target for Shh-associated medulloblastoma.

LC–MS-Based Urine Metabolomics Analysis for the Diagnosis and Monitoring of Medulloblastoma

Medulloblastoma (MB) is the most common type of brain cancer in pediatric patients. Body fluid biomarkers will be helpful for clinical diagnosis and treatment. In this study, liquid chromatography–mass spectrometry (LC–MS)-based metabolomics was used to identify specific urine metabolites of MB in a cohort, including 118 healthy controls, 111 MB patients, 31 patients with malignant brain cancer, 51 patients with benign brain disease, 29 MB patients 1 week postsurgery and 80 MB patients 1 month postsurgery. The results showed an apparent separation for MB vs. healthy controls, MB vs. benign brain diseases, and MB vs. other malignant brain tumors, with AUCs values of 0.947/0.906, 0.900/0.873, and 0.842/0.885, respectively, in the discovery/validation group. Among all differentially identified metabolites, 4 metabolites (tetrahydrocortisone, cortolone, urothion and 20-oxo-leukotriene E4) were specific to MB. The analysis of these 4 metabolites in pre- and postoperative MB urine samples showed that their levels returned to a healthy state after the operation (especially after one month), showing the potential specificity of these metabolites for MB. Finally, the combination of two metabolites, tetrahydrocortisone and cortolone, showed diagnostic accuracy for distinguishing MB from non-MB, with an AUC value of 0.851. Our data showed that urine metabolomics might be used for MB diagnosis and monitoring.

Integrated Analysis of Transcriptome Data Revealed AURKA and KIF20A as Critical Genes in Medulloblastoma Progression

Medulloblastoma is the neuroepithelial tumor with the highest degree of malignancy in the central nervous system, accounting for about 8% to 10% of children’s brain tumors. It has a high degree of malignancy and is easily transmitted through cerebrospinal fluid, with a relatively poor prognosis. Although medulloblastoma has been widely studied and treated, its molecular mechanism remains unclear. To determine which gene plays a crucial role in medulloblastoma development and progression, we analyzed three microarray datasets from Gene Expression Omnibus. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes were used to detect and evaluate differentially expressed genes. Protein interaction network was established, and the hub genes were determined in cytoHubba through various assessment methods, while the target genes were screened out using survival analysis. Ultimately, human medulloblastoma samples were utilized to confirm target gene expression. In conclusion, This study found that aurora kinase A (AURKA) and kinesin family member 20A (KIF20A) may be involved in the initiation and development of medulloblastoma, have a close association with prognosis, and may become a potential therapeutic target and prognostic marker of MED.

Inhibiting ALK2/ALK3 Signaling to Differentiate and Chemo-Sensitize Medulloblastoma

Simple Summary

Many cancers re-emerge after treatment, despite the sensitivity of the bulk of tumor cells to treatments. This observation has led to the ‘cancer stem cell’ (CSCs) hypothesis, stating that a subpopulation of cancer cells survive therapy and lead to tumor relapse. However, the lack of universal markers to target CSCs is the main constraint to fully eradicate the CSC pool. Differentiation therapy (DT) might in principle suppress tumorigenesis through conversion of undifferentiated cancer cells of high malignancy into differentiated cells of low tumorigenic potential. Here, we provide evidence that CSCs of medulloblastoma can be forced to resume their differentiation potential by inhibiting the BMP4–ALK2/3 axis, providing a new entry point for medulloblastoma treatment.

Abstract

Background: Medulloblastoma (MB) is a malignant pediatric brain tumor, and it represents the leading cause of death related to cancer in childhood. New perspectives for therapeutic development have emerged with the identification of cancer stem cells (CSCs) displaying tumor initiating capability and chemoresistance. However, the mechanisms responsible for CSCs maintenance are poorly understood. The lack of a universal marker signature represents the main constraints to identify and isolate CSCs within the tumor. Methods: To identify signaling pathways promoting CSC maintenance in MB, we combined tumorsphere assays with targeted neurogenesis PCR pathway arrays. Results: We showed a consistent induction of signaling pathways regulating pluripotency of CSCs in all the screened MB cells. BMP4 signaling was consistently enriched in all tumorsphere(s) independently of their specific stem-cell marker profile. The octamer-binding transcription factor 4 (OCT4), an important regulator of embryonic pluripotency, enhanced CSC maintenance in MBs by inducing the BMP4 signaling pathway. Consistently, inhibition of BMP4 signaling with LDN-193189 reduced stem-cell traits and promoted cell differentiation. Conclusions: Our work suggests that interfering with the BMP4 signaling pathway impaired the maintenance of the CSC pool by promoting cell differentiation. Hence, differentiation therapy might represent an innovative therapeutic to improve the current standard of care in MB patients.

Inhibition of lncRNA NEAT1 sensitizes medulloblastoma cells to cisplatin through modulating the miR-23a-3p-glutaminase (GLS) axis

Medulloblastoma (MB) is a commonly occurring brain malignancy in adolescence. Currently, the combination of chemotherapy with subsequent irradiation is a regular therapeutic strategy. However, high dosage of chemotherapy is associated with drug resistance and side effects. The long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1), which is frequently overexpressed in diverse human tumors, is correlated with worse survival rate in cancer patients. Currently, the precise roles of NEAT1 in MB and chemoresistance remain unclear. Our study aimed to investigate the biological functions of NEAT1 in cisplatin-resistant medulloblastoma. We report that NEAT1 was significantly upregulated in medulloblastoma patient specimens. Silencing NEAT1 significantly suppressed MB cell proliferation and sensitized MB cells to cisplatin. In cisplatin-resistant MB cell line, DAOY Cis R, NEAT1 expression, and glutamine metabolism were remarkably upregulated in cisplatin-resistant cells. Under low glutamine supply, cisplatin-resistant cells displayed increased cisplatin sensitivity. Bioinformatical analysis and luciferase assay uncovered that NEAT1 functions as a ceRNA of miR-23a-3p to downregulate its expressions in MB cells. Moreover, miR-23a-3p was apparently downregulated in MB patient tissues and cisplatin resistant MB cells. We identified GLS (glutaminase), a glutamine metabolism enzyme, was directly targeted by miR-23a-3p in MB cells. Rescue experiments demonstrated restoration of miR-23a-3p in NEAT1-overexpressing DAOY cisplatin resistant cells successfully overcame the NEAT1-promoted cisplatin resistance by targeting GLS. In general, our results revealed new molecular mechanisms for the lncRNA-NEAT1-mediated cisplatin sensitivity of MB.

Risk Factors for Survival in Patients With Medulloblastoma: A Systematic Review and Meta-Analysis

Background

Conventional parameters show limited and unreliable correlations with medulloblastoma prognosis.

Aim

To evaluate the factors influencing overall survival (OS), event-free survival (EFS), and progression-free survival (PFS) in patients with medulloblastoma.

Methods

PubMed, EMBASE, the Cochrane Library, and Web of Science were searched for studies published up to May 2021. The associations between various clinical and treatment factors and survival parameters were assessed.

Results

Twenty-nine studies (8455 patients) were included. Desmoplastic medulloblastoma (HR=0.41, 95%CI: 0.31-0.56), M0 disease (HR=2.07, 95%CI: 1.48-2.89), WNT, SSH, group 4 (all P<0.05 vs. group 3), GTR vs. STR (HR=1.37, 95%CI: 1.04-1.08), radiotherapy (HR=0.45, 95%CI: 0.20-0.80), craniospinal irradiation (HR=0.49, 95%CI: 0.38-0.64), and high 5hmC levels (HR=2.90, 95%CI: 1.85-4.55) were associated with a better OS. WNT, SSH, group 4 (all P<0.05 vs. group 3), residual tumor ≤1.5 cm2 (HR=2.08, 95%CI: 1.18-3.68), GTR vs. STR (HR=1.31, 95%CI: 1.03-1.68), craniospinal irradiation (HR=0.46, 95%CI: 0.37-0.57), high 5hmC levels (HR=3.10, 95%CI: 2.01-4.76), and <49 days between resection and radiotherapy (HR=2.54, 95%CI: 1.48-4.37) were associated with better PFS. Classic vs. desmoplastic medulloblastoma (HR=1.81, 95%CI: 1.04-3.16), SSH, WNT (both P<0.05 vs, non-SSH/non-WNT), GTR vs. STR (HR=2.01, 95%CI: 1.42-2.85), and radiotherapy (HR=0.31, 95%CI: 0.15-0.64) were associated with a better EFS.

Conclusion

Histology, molecular subgroup, GTR, and radiotherapy are significantly associated with survival parameters in patients with medulloblastoma. Nevertheless, high-quality prospective cohort studies are necessary to improve the conclusions.

Identification of Potential Key Genes and Molecular Mechanisms of Medulloblastoma Based on Integrated Bioinformatics Approach

Background

Medulloblastoma (MB) is the most occurring brain cancer that mostly happens in childhood age. This cancer starts in the cerebellum part of the brain. This study is designed to screen novel and significant biomarkers, which may perform as potential prognostic biomarkers and therapeutic targets in MB.

Methods

A total of 103 MB-related samples from three gene expression profiles of GSE22139, GSE37418, and GSE86574 were downloaded from the Gene Expression Omnibus (GEO). Applying the limma package, all three datasets were analyzed, and 1065 mutual DEGs were identified including 408 overexpressed and 657 underexpressed with the minimum cut-off criteria of ∣log fold change | >1 and P < 0.05. The Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and WikiPathways enrichment analyses were executed to discover the internal functions of the mutual DEGs. The outcomes of enrichment analysis showed that the common DEGs were significantly connected with MB progression and development. The Search Tool for Retrieval of Interacting Genes (STRING) database was used to construct the interaction network, and the network was displayed using the Cytoscape tool and applying connectivity and stress value methods of cytoHubba plugin 35 hub genes were identified from the whole network.

Results

Four key clusters were identified using the PEWCC 1.0 method. Additionally, the survival analysis of hub genes was brought out based on clinical information of 612 MB patients. This bioinformatics analysis may help to define the pathogenesis and originate new treatments for MB.

Effects of Lovastatin on Brain Cancer Cells

Although brain tumors occur less frequently than other forms of cancer, they have one of the bleakest prognoses with low survival rates. The conventional treatment for brain tumors includes surgery, radiotherapy, and chemotherapy. However, resistance to treatment remains a problem with recurrence shortly following. The resistance to treatment may be caused by cancer stem cells (CSCs), a subset of brain tumor cells with the affinity for self-renewal and differentiation into multiple cell lineages. An emerging approach to targeting CSCs in brain tumors is through repurposing the lipid-lowering medication, lovastatin. Lovastatin is a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor that impacts the mevalonate pathway. The inhibition of intermediates in the mevalonate pathway affects signaling cascades and oncogenes associated with brain tumor stem cells (BTSC). In this review, we show the possible mechanisms where lovastatin can target BTSC for different varieties of malignant brain tumors.

Role of MicroRNAs in the Development and Progression of the Four Medulloblastoma Subgroups

Medulloblastoma is the most frequent malignant brain tumour in children. Medulloblastoma originate during the embryonic stage. They are located in the cerebellum, which is the area of the central nervous system (CNS) responsible for controlling equilibrium and coordination of movements. In 2012, medulloblastoma were divided into four subgroups based on a genome-wide analysis of RNA expression. These subgroups are named Wingless, Sonic Hedgehog, Group 3 and Group 4. Each subgroup has a different cell of origin, prognosis, and response to therapies. Wingless and Sonic Hedgehog medulloblastoma are so named based on the main mutation originating these tumours. Group 3 and Group 4 have generic names because we do not know the key mutation driving these tumours. Gene expression at the post-transcriptional level is regulated by a group of small single-stranded non-coding RNAs. These microRNA (miRNAs or miRs) play a central role in several cellular functions such as cell differentiation and, therefore, any malfunction in this regulatory system leads to a variety of disorders such as cancer. The role of miRNAs in medulloblastoma is still a topic of intense clinical research; previous studies have mostly concentrated on the clinical entity of the single disease rather than in the four molecular subgroups. In this review, we summarize the latest discoveries on miRNAs in the four medulloblastoma subgroups.

Effects of different molecular subtypes and tumor biology on the prognosis of medulloblastoma

PURPOSE

Medulloblastoma is one of the most common malignant brain tumors in the pediatric population. Recent studies identified four distinct medulloblastoma subgroups with different molecular alterations and pathways, and natural courses and outcomes. To evaluate the results of surgical and medical treatments of patients with medulloblastoma and compare them among the medulloblastoma subgroups.

METHODS

The clinical and radiological features, medical and surgical management and treatment outcomes and their correlation with molecular subgroups of 58 patients treated for medulloblastoma in the last 20 years were evaluated.

RESULTS

Fifty-eight patients, of whom 35 were male and 23 were female, were evaluated. The median age was 6 years (range, 1-19 years). The most common symptoms were nausea and vomiting (60%). Forty-three percent of the patients had headache and 40% had ataxia. Previous pathology reports revealed that 43 (74%), eight (14%), five (8%), and two (3%) had classic, desmoplastic, desmoplastic/nodular, and anaplastic morphologies, respectively. After the subgroup analyses, five patients (12%) were attributed to the wingless subgroup (WNT) group; 14 (32.5%), to the sonic hedgehog subgroup (SHH) group; and 24 (56%), to the non-WNT non-SHH group. On the basis of immunohistochemical analysis results, 15 patients could not be attributed to any subgroups. The clinical risk groups (average vs high-risk) and age at diagnosis (≥ 3 years vs < 3 years of age) were significant for 5-year event free survival (86% vs 43%, p:0.011 and 59% vs 36%, p:0.039). There was no significant difference in survival or event free survival according to molecular subtypes in this cohort.

CONCLUSION

In corporation of molecular features to the clinicopathologic classification leads to risk-adapted treatment. Although the molecular subgroups did not affect outcome significantly in this study, more studies with larger numbers of patients are needed to understand the tumor pathophysiology of medulloblastoma and design the future medical practice.

Clinical applications of artificial intelligence and radiomics in neuro-oncology imaging

This article is a comprehensive review of the basic background, technique, and clinical applications of artificial intelligence (AI) and radiomics in the field of neuro-oncology. A variety of AI and radiomics utilized conventional and advanced techniques to differentiate brain tumors from non-neoplastic lesions such as inflammatory and demyelinating brain lesions. It is used in the diagnosis of gliomas and discrimination of gliomas from lymphomas and metastasis. Also, semiautomated and automated tumor segmentation has been developed for radiotherapy planning and follow-up. It has a role in the grading, prediction of treatment response, and prognosis of gliomas. Radiogenomics allowed the connection of the imaging phenotype of the tumor to its molecular environment. In addition, AI is applied for the assessment of extra-axial brain tumors and pediatric tumors with high performance in tumor detection, classification, and stratification of patient's prognoses.

Gene clusters based on OLIG2 and CD276 could distinguish molecular profiling in glioblastoma

Background

The molecular profiling of glioblastoma (GBM) based on transcriptomic analysis could provide precise treatment and prognosis. However, current subtyping (classic, mesenchymal, neural, proneural) is time-consuming and cost-intensive hindering its clinical application. A simple and efficient method for classification was imperative.

Methods

In this study, to simplify GBM subtyping more efficiently, we applied a random forest algorithm to conduct 26 genes as a cluster featured with hub genes, OLIG2 and CD276. Functional enrichment analysis and Protein–protein interaction were performed using the genes in this gene cluster. The classification efficiency of the gene cluster was validated by WGCNA and LASSO algorithms, and tested in GSE84010 and Gravandeel’s GBM datasets.

Results

The gene cluster (n = 26) could distinguish mesenchymal and proneural excellently (AUC = 0.92), which could be validated by multiple algorithms (WGCNA, LASSO) and datasets (GSE84010 and Gravandeel’s GBM dataset). The gene cluster could be functionally enriched in DNA elements and T cell associated pathways. Additionally, five genes in the signature could predict the prognosis well (p = 0.0051 for training cohort, p = 0.065 for test cohort).

Conclusions

Our study proved the accuracy and efficiency of random forest classifier for GBM subtyping, which could provide a convenient and efficient method for subtyping Proneural and Mesenchymal GBM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03083-y.

Long non-coding RNAs as a predictive markers of group 3 medulloblastomas

ObjectiveThe appropriate treatments for the different molecular subgroups of medulloblastomas are challenging to determine. Hence, this study aimed to examine the expression profiles of long non-coding RNAs (LncRNAs) to determine a marker that may be important for treatment selection in these subgroups.MethodsChanges in the expression of LncRNAs in the tissues of patients with medulloblastoma, which are classified into four subgroups according to their clinical characteristics and gene expression profiles, were examined via reverse transcription polymerase chain reaction. Moreover, there association with patient prognosis was evaluated.ResultsThe expression levels of MALAT1 and SNGH16 were significantly higher in patients with group 3 medulloblastoma than in those with other subtypes. Patients with high expression levels of MALAT1 and SNGH16 had a relatively shorter overall survival than those with low expression levels.ConclusionsPatients with group 3 medulloblastoma have a high MALAT1 level, which is associated with poor prognosis. Therefore, MALAT1 can be a new therapeutic target in medulloblastoma.

Updates on the 2016 World Health Organization Classification of Pediatric Tumors of the Central Nervous System - a systematic review

Tumors of the central nervous system (CNS) represent the main cause of death through solid tumors in children and the second most frequent neoplasm in this patient group. The poor survival rate is due to many factors, such as the large diversity of morphological features, the particular micro-environmental characteristics of the nervous tissue, the relative rareness in relation to other childhood diseases, which leads to late diagnosis and the limited effectiveness of the available treatment options. Up until 2016, brain tumors were classified according to their histologic features. The new 2016 World Health Organization (WHO) Classification of CNS tumors incorporates molecular features, alongside the immunohistology, in order to provide a more accurate understanding of the disease. The treatment consists of surgery, radiation therapy and chemotherapy. We decided to review the literature on this pathology, in order to show the importance of the recent discoveries in this field.

Multi-omics analysis of intertumoral heterogeneity within medulloblastoma uncharted-pathway subtypes

Medulloblastoma is a common pediatric malignant brain tumor. There were four consensus molecular subgroups (WNT, SHH, Group3 and Group4). Group 3 and Group 4 tumors exhibited a great degree of transcriptional overlap, and were neither derived from exact pathway aberration. We investigated transcriptional and chromatin accessibility of medulloblastoma by multi-omics single-cell analysis. Our work identified inter- and intra-tumoral heterogeneity within the Group 3, Group 4 and Group 3/4 intermediate subgroups. Unsupervised cluster of each tumor identified 9 cell clusters with transcriptional profiles and 6 cell clusters with chromatin accessibility profiles. OTX2 had the highest activity and expression level across the clusters in a special cluster based on open chromatin single-cell profilings. We identified multiple genes as a significant targeted gene within the OTX2 target genes, which made sense in prognosis. We analyzed the copy-number-variations which presented with expected subgroup distribution from transcriptional and chromatin accessibility profiles. Collectively, these data provide novel insights into Group 3 and Group 4 medulloblastoma and provide a potential therapeutic target.

Epigenetic regulation in medulloblastoma pathogenesis revealed by genetically engineered mouse models

Medulloblastoma is the most common malignant cerebellar tumor in children. Recent technological advances in multilayered ’omics data analysis have revealed 4 molecular subgroups of medulloblastoma (Wingless/int, Sonic hedgehog, Group3, and Group4). (Epi)genomic and transcriptomic profiling on human primary medulloblastomas has shown distinct oncogenic drivers and cellular origin(s) across the subgroups. Despite tremendous efforts to identify the molecular signals driving tumorigenesis, few of the identified targets were druggable; therefore, a further understanding of the etiology of tumors is required to establish effective molecular‐targeted therapies. Chromatin regulators are frequently mutated in medulloblastoma, prompting us to investigate epigenetic changes and the accompanying activation of oncogenic signaling during tumorigenesis. For this purpose, we have used germline and non‐germline genetically engineered mice to model human medulloblastoma and to conduct useful, molecularly targeted, preclinical studies. This review discusses the biological implications of chromatin regulator mutations during medulloblastoma pathogenesis, based on recent in vivo animal studies.

WNT-activated Pediatric Medulloblastoma Associated With Metastasis to the Suprasellar Region and Hypopituitarism

We report on a rare association of WNT-activated medulloblastoma with metastasis to the suprasellar region. Medulloblastoma is the commonest brain tumor in children, and the most common pattern of metastatic disease is that of leptomeningeal involvement and spinal metastasis. Historically, medulloblastoma patients were categorized into different risk groups on the basis of age, histology, size of residium after surgery, and metastatic status, but the discovery of at least 4 molecular subgroups has changed the way these tumors are now treated. We report a 6-year-old patient who had a rare association of WNT-activated medulloblastoma with suprasellar metastasis and went on to develop hypopituitarism during the course of treatment. He remains alive 1 year after completing treatment.

Radiation-induced intracranial aneurysm presenting with acute hemorrhage in a child treated for medulloblastoma

Radiation-associated aneurysms are rare, difficult to treat, and associated with high morbidity and mortality when ruptured, compared with aneurysms unrelated to radiation treatment. We present a 16-year-old patient with a radiation-induced intracranial aneurysm arising from the left posterior inferior cerebellar artery (PICA), 10 years following radiotherapy for medulloblastoma. The patient successfully underwent endovascular coil embolization of the parent artery across the neck of the aneurysm. CT angiography and MRI in the days following the procedure demonstrated maintained flow in the anterior and lateral medullary PICA segments with no brainstem infarct.

Loss of 5-Hydroxymethylcytosine as an Epigenetic Signature That Correlates With Poor Outcomes in Patients With Medulloblastoma

Medulloblastoma, as the most common malignant brain tumor in children, exhibits highly dysregulated DNA methylation. The novel epigenetic marker—5-hydroxymethylcytosine (5hmC) plays essential role in gene regulation during brain development and in brain tumors. However, the biological and clinical implications of 5hmC in medulloblastoma are still unclear. Here, we detected global 5hmC levels in two independent medulloblastoma patient cohorts (discovery cohort: n = 81; validation cohort: n = 171) using ultra-high performance liquid chromatography-tandem mass spectrometry analysis. Immunohistochemistry was used to identify the cell proliferation and expression of Ten-eleven translocation 1 and 2 (TET1/2). The prognostic impacts of covariates on progression-free survival (PFS) and overall survival (OS) were evaluated using multivariate Cox hazards regression models. We observed that global 5hmC levels were decreased in medulloblastomas compared to normal cerebellums (P < 0.001). Multivariate analysis showed that low global 5hmC levels correlated with poor PFS and OS rates (discovery cohort: PFS: P = 0.003, OS: P = 0.002; validation cohort: PFS: P = 0.0002, OS: P = 0.001). Immunohistochemistry showed an inverse correlation between 5hmC score and Ki-67 index (r = -0.747, P < 0.0001). Moreover, 5hmC score in MB samples was associated with nuclear expression of TET1 (r = -0.419, P = 0.003) and TET2 (r = -0.399, P = 0.005) proteins. Our study demonstrates that loss of 5hmC is an epigenetic biomarker in medulloblastomas. Our results indicate that 5hmC could be a candidate prognostic indicator for improving survival prediction of risk stratification in patients with medulloblastoma.

Ubiquitin ligases and medulloblastoma: genetic markers of the four consensus subgroups identified through transcriptome datasets

The ubiquitin proteasome system regulates key cellular processes in normal and in cancer cells. Herein, we review published data on the role of ubiquitin ligases in the four major subgroups of medulloblastoma (MB). While conventional literature serves as an initial source of information on cellular pathways in MB, large publicly available datasets of gene expression can be used to add information not previously identified in the literature. By analysing the publicly available Cavalli dataset, we show that increased expression of ZNRF3 characterizes the WNT subgroup of MB. The ZNRF3 gene codes for an E3 ligase associated with WNT receptors. Loss of a copy of chromosome 6 in a subtype of the WNT group was associated with decreased expression of the gene encoding the E3 ligase RNF146. While the E3 ligase SMURF regulates SHH receptors, increased expression of the gene encoding the Cullin Ring E3 adaptor PPP2R2C was statistically a better genetic marker of the SHH group. Genes whose expression was statistically strongly related to Group 3 included the E3 ligase gene TRIM58, and the gene for the E3 ligase adaptor, PPP2R2B. Group 4 MB was associated with expression of genes encoding several E3 ligases and E3 ligase adaptors involved in ribosome biogenesis. Increased expression of the genes encoding the E3 ligase adaptors and transcription repressors ZBTB18 and ZBTB38 were also noted in subgroup 4. These data suggest that several E3 ligases and their adaptors should be investigated as therapeutic targets for subgroup specific MB brain tumors.

Updates in Pediatric Malignant Gliomas

Malignant gliomas constitute a smaller portion of brain tumors in children compared with adults. Nevertheless, they can be devastating tumors with poor prognosis. Recent advances and improved understanding of the genetic and molecular characterization of pediatric brain tumors, including those of malignant gliomas, have led to the reclassification of many pediatric brain tumors and new entities have been defined. In this paper, we will present some of the more recent characterization and pertinent changes in pediatric high-grade gliomas, along with the conventional and advanced imaging features associated with these entities. Implications of the recent changes in pediatric malignant glioma classifications will also be discussed.

Medulloblastoma malignant biological behaviors are associated with HOTAIR/miR-483-3p/CDK4 axis

BACKGROUND

Medulloblastoma is the most common malignant brain tumor in children. Although the 5-year survival rate is high, patients with relapsed medulloblastoma have a guarded prognosis. HOX transcript antisense RNA (HOTAIR) has been proved to be related to the metastasis of various tumors. Therefore, the molecular mechanism of HOTAIR in medulloblastoma cells was investigated in this study.

METHODS

HOTAIR was stably silenced in medulloblastoma cells (Daoy and D341). Cell proliferation and apoptosis were detected by 5'-Bromo-2'-deoxyuridine (BrdU) staining, Hoechst 33342 staining, immunohistochemical (IHC), Terminal-deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) and flow cytometry, respectively. The targeted relationship between HOTAIR/Cyclin-dependent kinase 4 (CDK4) and miR-483-3p were predicted by bioinformatics and confirmed by luciferase reporter assay. Balb/C nude mice were inoculated with shRNA-HOTAIR transfected Daoy cells.

RESULTS

We found that the down-regulation of HOTAIR inhibited proliferation and induced apoptosis. Sh-RNA-HOTAIR also inhibited the expression of CKD4. The CDK4 dependent increase of cell proliferation and decrease of cell apoptosis were reversed by shRNA-HOTAIR. Finally, a xenograft model of medulloblastoma in nude mice was built, and the effect of shRNA-HOTAIR on the growth of tumors was analyzed by RT-PCR, immunofluorescence staining, and TUNEL staining. The data suggested interference of HOTAIR inhibited the growth, tumor weight, cell proliferation, and promoted cell apoptosis.

CONCLUSIONS

Our study altogether demonstrated HOTAIR influence cell proliferation and apoptosis by regulation of miR-483-3p and CDK4 in medulloblastoma cells. HOTAIR can be used as a candidate for potential applications in the treatment of medulloblastoma.

Molecular subgrouping of medulloblastoma based on few-shot learning of multitasking using conventional MR images: a retrospective multicenter study

Background

The determination of molecular subgroups—wingless (WNT), sonic hedgehog (SHH), Group 3, and Group 4—of medulloblastomas is very important for prognostication and risk-adaptive treatment strategies. Due to the rare disease characteristics of medulloblastoma, we designed a unique multitask framework for the few-shot scenario to achieve noninvasive molecular subgrouping with high accuracy.

Methods

We introduced a multitask technique based on mask regional convolutional neural network (Mask-RCNN). By effectively utilizing the comprehensive information including genotyping, tumor mask, and prognosis, multitask technique, on the one hand, realized multi-purpose modeling and simultaneously, on the other hand, promoted the accuracy of the molecular subgrouping. One hundred and thirteen medulloblastoma cases were collected from 4 hospitals during the 8-year period in the retrospective study, which were divided into 3-fold cross-validation cohorts (N = 74) from 2 hospitals and independent testing cohort (N = 39) from the other 2 hospitals. Comparative experiments of different auxiliary tasks were designed to illustrate the effect of multitasking in molecular subgrouping.

Results

Compared to the single-task framework, the multitask framework that combined 3 tasks increased the average accuracy of molecular subgrouping from 0.84 to 0.93 in cross-validation and from 0.79 to 0.85 in independent testing. The average area under the receiver operating characteristic curves (AUCs) of molecular subgrouping were 0.97 in cross-validation and 0.92 in independent testing. The average AUCs of prognostication also reached to 0.88 in cross-validation and 0.79 in independent testing. The tumor segmentation results achieved the Dice coefficient of 0.90 in both cohorts.

Conclusions

The multitask Mask-RCNN is an effective method for the molecular subgrouping and prognostication of medulloblastomas with high accuracy in few-shot learning.

Update on Pediatric Brain Tumors: the Molecular Era and Neuro-immunologic Beginnings

PURPOSE OF REVIEW

To provide an update on the current landscape of pediatric brain tumors and the impact of novel molecular insights on classification, diagnostics, and therapeutics.

RECENT FINDINGS

Scientific understanding of the genetic basis of central nervous system tumors has expanded rapidly over the last several years. The shift in classification of tumors to a molecularly based schema, accompanied by a growing number of early phase clinical trials of therapies aimed at inhibiting tumoral genetic and epigenetic programs, as well as those attempting to harness and magnify the immune response, has allowed a deeper pathophysiologic understanding of brain tumors and simultaneously provided opportunities for novel treatment. Over the last 5 years, there has been tremendous growth in the field of pediatric neuro-oncology with increasing understanding of the genetic and epigenetic heterogeneity of CNS tumors. Attempts are underway to translate these insights into tumor-specific treatments.

Identification of Core Genes and Pathways in Medulloblastoma by Integrated Bioinformatics Analysis

Medulloblastoma (MB) is one of the most common intracranial malignancies in children. The present study applied integrated bioinformatics to identify potential core genes associated with the pathogenesis of MB and reveal potential molecular mechanisms. Through the integrated analysis of multiple data sets from the Gene Expression Omnibus (GEO), 414 differentially expressed genes (DEGs) were identified. Combining the protein-protein interaction (PPI) network analysis with gene set enrichment analysis (GSEA), eight core genes, including CCNA2, CCNB1, CCNB2, AURKA, CDK1, MAD2L1, BUB1B, and RRM2, as well as four core pathways, including "cell cycle", "oocyte meiosis", "p53 pathway" and "DNA replication" were selected. In independent data sets, the core genes showed superior diagnostic values and significant prognostic correlations. Moreover, in the pan-caner data of the cancer genome atlas (TCGA), the core genes were also widely abnormally expressed. In conclusion, this study identified core genes and pathways of MB through integrated analysis to deepen the understanding of the molecular mechanisms underlying the MB and provide potential targets and pathways for diagnosis and treatment of MB.

miR-196B-5P and miR-200B-3P Are Differentially Expressed in Medulloblastomas of Adults and Children

Medulloblastoma is a highly aggressive brain tumor that typically affects children, while in adults it represents ~1% of all brain tumors. Little is known about microRNA expression profile of the rare adult medulloblastoma. The main aim of this study was to identify peculiar differences in microRNA expression between childhood and adult medulloblastoma. Medulloblastomas were profiled for microRNA expression using the Exiqon Human miRNome panel (I + II) analyzing 752 microRNAs in a training set of six adult and six childhood cases. Then, the most differentially expressed microRNAs were validated in a total of 21 adult and 19 childhood cases. Eight microRNAs (miR-196b-5p, miR-183-5p, miR-200b-3p, miR-196a-5p, miR-193a-3p, miR-29c-3p, miR-33b-5p, and miR-200a-3p) were differentially expressed in medulloblastoma of adults and children. Analysis of the validation set confirmed that miR-196b-5p and miR-200b-3p were significantly overexpressed in medulloblastoma of adults as compared with those of children. We followed an in silico approach to investigate direct targets and the pathways involved for the two microRNAs (miR-196b and miR-200b) differently expressed between adult and childhood medulloblastoma. Adult and childhood medulloblastoma have different miRNA expression profiles. In particular, the differential dysregulation of miR-196b-5p and miR-200b-3p characterizes the miRNA profile of adult medulloblastoma and suggests potential targets for novel diagnostic, prognostic, or therapeutic strategies.

Immunotherapy for Medulloblastoma: Current Perspectives

Background

Immune-mediated therapies have transformed the treatment of metastatic melanoma and renal, bladder, and both small and non-small cell lung carcinomas. However, immunotherapy is yet to demonstrate dramatic results in brain tumors like medulloblastoma for a variety of reasons. Recent pre-clinical and early phase human trials provide encouraging results that may overcome the challenges of central nervous system (CNS) tumors, which include the intrinsic immunosuppressive properties of these cancers, a lack of antigen targets, antigenic variability, and the immune-restrictive site of the CNS. These studies highlight the growing potential of immunotherapy to treat patients with medulloblastoma, a disease that is a frequent cause of morbidity and mortality to children and young adults.

Methods

We conducted an inclusive review of the PubMed-indexed literature and studies listed in clinicaltrials.gov using combinations of the keywords medulloblastoma, immunotherapy, CNS tumors, brain tumors, vaccines, oncolytic virus, natural killer, and CAR T to identify trials evaluating immunotherapy in preclinical experiments or in patients with medulloblastoma. Given a limited number of investigations using immunotherapy to treat patients with medulloblastoma, 24 studies were selected for final analysis and manuscript citation.

Results

This review presents results from pre-clinical studies in medulloblastoma cell lines, animal models, and the limited trials involving human patients.

Conclusion

From our review, we suggest that cancer vaccines, oncolytic viral therapy, natural killer cells, and CAR T therapy hold promise against the innate immunosuppressive properties of medulloblastoma in order to prolong survival. There is an unmet need for immunotherapy regimens that target overexpressed antigens in medulloblastoma tumors. We advocate for more combination treatment clinical trials using conventional surgical and radiochemotherapy approaches in the near-term clinical development.

Geniposide exhibits anticancer activity to medulloblastoma cells by downregulating microRNA-373

BACKGROUND

Medulloblastoma is a common tumor originates from central nervous system in children with metastatic potential. Geniposide is the major active ingredient separated from the fruit of Gardenia jasminoides Ellis. Herein, we tested the possible anticancer activity of geniposide on human medulloblastoma cells, as well as the potential underlying molecular mechanisms.

METHODS

Firstly, followed by geniposide incubation, cell viability, proliferation, apoptosis, migration, and invasion of medulloblastoma Daoy cells, along with microRNA-373 (miR-373) expression were tested, respectively. Then, the influences of miR-373 overexpression in the reduction of medulloblastoma cell proliferation, migration, and invasion and the elevation of apoptosis, triggered by geniposide treatment, were re-investigated. Finally, the Ras/Raf/MEK/ERK pathway activity was analyzed.

RESULTS

Geniposide treatment inhibited medulloblastoma cell viability, proliferation, migration, and invasion, but promoted cell apoptosis. Surprisingly, miR-373 expression in medulloblastoma cells was obviously downregulated by geniposide treatment. miR-373 overexpression reversed the effects of geniposide on Daoy cells. Furthermore, geniposide hindered the Ras/Raf/MEK/ERK pathway by downregulating miR-373 expression.

CONCLUSION

Geniposide exhibited anticancer activity on human medulloblastoma cells and blocked Ras/Raf/MEK/ERK pathway by downregulating miR-373 expression.

A Sexually Dimorphic Role for STAT3 in Sonic Hedgehog Medulloblastoma

Medulloblastoma is the most common malignant brain tumor in children and represents 20% of all pediatric central nervous system neoplasms. While advances in surgery, radiation and chemotherapy have improved overall survival, the lifelong sequelae of these treatments represent a major health care burden and have led to ongoing efforts to find effective targeted treatments. There is a well-recognized male bias in medulloblastoma diagnosis, although the mechanism remains unknown. Herein, we identify a sex-specific role for the transcription factor Signal Transducer and Activator of Transcription 3 (STAT3) in the Sonic Hedgehog (SHH) medulloblastoma subgroup. Specific deletion of Stat3 from granule cell precursors in a spontaneous mouse model of SHH medulloblastoma completely protects male, but not female mice from tumor initiation. Segregation of SHH medulloblastoma patients into high and low STAT3 expressing cohorts shows that low STAT3 expression correlates with improved overall survival in male patients. We observe sex specific changes in IL-10 and IL-6 expression and show that IL-6 stimulation enhances SHH-mediated gene transcription in a STAT3-dependent manner. Together these data identify STAT3 as a key molecule underpinning the sexual dimorphism in medulloblastoma.

Upregulation of the chromatin remodeler HELLS is mediated by YAP1 in Sonic Hedgehog Medulloblastoma

Medulloblastoma is a malignant pediatric tumor that arises from neural progenitors in the cerebellum. Despite a five-year survival rate of ~70%, nearly all patients incur adverse side effects from current treatment strategies that drastically impact quality of life. Roughly one-third of medulloblastoma are driven by aberrant activation of the Sonic Hedgehog (SHH) signaling pathway. However, the scarcity of genetic mutations in medulloblastoma has led to investigation of other mechanisms contributing to cancer pathogenicity including epigenetic regulation of gene expression. Here, we show that Helicase, Lymphoid Specific (HELLS), a chromatin remodeler with epigenetic functions including DNA methylation and histone modification, is induced by Sonic Hedgehog (SHH) in SHH-dependent cerebellar progenitor cells and the developing murine cerebella. HELLS is also up-regulated in mouse and human SHH medulloblastoma. Others have shown that HELLS activity generally results in a repressive chromatin state. Our results demonstrate that increased expression of HELLS in our experimental systems is regulated by the oncogenic transcriptional regulator YAP1 downstream of Smoothened, the positive transducer of SHH signaling. Elucidation of HELLS as one of the downstream effectors of the SHH pathway may lead to novel targets for precision therapeutics with the promise of better outcomes for SHH medulloblastoma patients.

Single-Cell Transcriptomics in Medulloblastoma Reveals Tumor-Initiating Progenitors and Oncogenic Cascades during Tumorigenesis and Relapse

Progenitor heterogeneity and identities underlying tumor initiation and relapse in medulloblastomas remain elusive. Utilizing single-cell transcriptomic analysis, we demonstrated a developmental hierarchy of progenitor pools in Sonic Hedgehog (SHH) medulloblastomas, and identified OLIG2-expressing glial progenitors as transit-amplifying cells at the tumorigenic onset. Although OLIG2⁺ progenitors become quiescent stem-like cells in full-blown tumors, they are highly enriched in therapy-resistant and recurrent medulloblastomas. Depletion of mitotic Olig2⁺ progenitors or Olig2 ablation impeded tumor initiation. Genomic profiling revealed that OLIG2 modulates chromatin landscapes and activates oncogenic networks including HIPPO-YAP/TAZ and AURORA-A/MYCN pathways. Co-targeting these oncogenic pathways induced tumor growth arrest. Together, our results indicate that glial lineage-associated OLIG2⁺ progenitors are tumor-initiating cells during medulloblastoma tumorigenesis and relapse, suggesting OLIG2-driven oncogenic networks as potential therapeutic targets.

Simvastatin Induces Apoptosis in Medulloblastoma Brain Tumor Cells via Mevalonate Cascade Prenylation Substrates

Medulloblastoma is a common pediatric brain tumor and one of the main types of solid cancers in children below the age of 10. Recently, cholesterol-lowering “statin” drugs have been highlighted for their possible anti-cancer effects. Clinically, statins are reported to have promising potential for consideration as an adjuvant therapy in different types of cancers. However, the anti-cancer effects of statins in medulloblastoma brain tumor cells are not currently well-defined. Here, we investigated the cell death mechanisms by which simvastatin mediates its effects on different human medulloblastoma cell lines. Simvastatin is a lipophilic drug that inhibits HMG-CoA reductase and has pleotropic effects. Inhibition of HMG-CoA reductase prevents the formation of essential downstream intermediates in the mevalonate cascade, such as farnesyl pyrophosphate (FPP) and gernaylgerany parophosphate (GGPP). These intermediates are involved in the activation pathway of small Rho GTPase proteins in different cell types. We observed that simvastatin significantly induces dose-dependent apoptosis in three different medulloblastoma brain tumor cell lines (Daoy, D283, and D341 cells). Our investigation shows that simvastatin-induced cell death is regulated via prenylation intermediates of the cholesterol metabolism pathway. Our results indicate that the induction of different caspases (caspase 3, 7, 8, and 9) depends on the nature of the medulloblastoma cell line. Western blot analysis shows that simvastatin leads to changes in the expression of regulator proteins involved in apoptosis, such as Bax, Bcl-2, and Bcl-xl. Taken together, our data suggests the potential application of a novel non-classical adjuvant therapy for medulloblastoma, through the regulation of protein prenylation intermediates that occurs via inhibition of the mevalonate pathway.

Partnership for defining the impact of 12 selected rare CNS tumors: a report from the CBTRUS and the NCI-CONNECT

PURPOSE

Population-based cancer statistics, including histology-specific incidence, prevalence, and survival are essential to evaluating the total burden due to disease in a population. The National Cancer Institute's (NCI) Comprehensive Oncology Network Evaluating Rare CNS Tumors (NCI-CONNECT) was developed to better understand tumor biology and patient outcomes for 12 selected brain and other central nervous system (CNS) tumor histologies that are rare in adults to improve approaches to care and treatment. The aim of this study was to determine the incidence, prevalence, and survival of these selected rare histologies.

METHODS

Data from the Central Brain Tumor Registry of the United States (CBTRUS) from 2000 to 2014 were used to calculate average annual age-adjusted incidence rates (AAIR) per 100,000 population overall and by sex, race, ethnicity, and age. NCI's Surveillance, Epidemiology and End Results (SEER) data were used to calculate relative survival (RS) estimates. Point prevalence for 2014 was estimated using annual age-specific incidence and survival from CBTRUS and SEER, respectively.

RESULTS

Overall AAIR was 1.47 per 100,000 for all 12 rare histologies combined, with the highest histology-specific incidence in oligodendrogliomas (AAIR = 0.40/100,000). Overall, most histologies were more common in males, adults (age 40 + ), Whites, and non-Hispanics. Ependymomas were the most prevalent histology at 4.11 per 100,000; followed by oligodendrogliomas at 3.68 per 100,000. Relative survival at 1-, 5-, and 10-years was 82.3%, 64.0%, and 55.4%, respectively for all 12 selected brain and other CNS tumor types combined. Ependymomas had the highest RS (1-year = 94.2%, 5-year = 83.9%, 10-year = 78.6%) and gliosarcomas had the lowest relative survival rate (1-year = 42.5%, 5-year = 5.6%, 10-year = 2.9%) at all three time points.

CONCLUSIONS

Incidence and prevalence of these rare brain and other CNS tumor histologies have not been previously reported. Along with survival, these data provide a statistical foundation to understand the impact of these cancers and provide important disease-specific data for the design of prospective clinical trials.

Examining the biomarkers and molecular mechanisms of medulloblastoma based on bioinformatics analysis

Medulloblastoma (MB) is the most common malignant brain tumor in children. The aim of the present study was to predict biomarkers and reveal their potential molecular mechanisms in MB. The gene expression profiles of GSE35493, GSE50161, GSE74195 and GSE86574 were downloaded from the Gene Expression Omnibus (GEO) database. Using the Limma package in R, a total of 1,006 overlapped differentially expressed genes (DEGs) with the cut-off criteria of P<0.05 and |log₂fold-change (FC)|>1 were identified between MB and normal samples, including 540 upregulated and 466 downregulated genes. Furthermore, the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were also performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID) online tool to analyze functional and pathway enrichment. The Search Tool for Retrieval of Interacting Genes database was subsequently used to construct a protein-protein interaction (PPI) network and the network was visualized in Cytoscape. The top 11 hub genes, including CDK1, CCNB1, CCNB2, PLK1, CDC20, MAD2L1, AURKB, CENPE, TOP2A, KIF2C and PCNA, were identified from the PPI network. The survival curves for hub genes in the dataset GSE85217 predicted the association between the genes and survival of patients with MB. The top 3 modules were identified by the Molecular Complex Detection plugin. The results indicated that the pathways of DEGs in module 1 were primarily enriched in cell cycle, progesterone-mediated oocyte maturation and oocyte meiosis; and the most significant functional pathways in modules 2 and 3 were primarily enriched in mismatch repair and ubiquitin-mediated proteolysis, respectively. These results may help elucidate the pathogenesis and design novel treatments for MB.

Medulloblastoma: optimizing care with a multidisciplinary approach

Medulloblastoma is a malignant tumor of the cerebellum and the most frequent malignant brain tumor in children. The standard of care consists of maximal resection surgery, followed by craniospinal irradiation and chemotherapy. Such treatment allows long-term survival rates of nearly 70%; however, there are wide disparities among patient outcomes, and in any case, major long-term morbidity is observed with conventional treatment. In the last two decades, the molecular understanding of medulloblastoma has improved drastically, allowing us to revolutionize our understanding of medulloblastoma pathophysiological mechanisms. These advances led to an international consensus in 2010 that defined four prognostic molecular subgroups named after their affected signaling pathways, that is, WNT, SHH, Group 3 and Group 4. The molecular understanding of medulloblastoma is starting to translate through to clinical settings due to the development of targeted therapies. Moreover, recent improvements in radiotherapy modalities and the reconsideration of craniospinal irradiation according to the molecular status hold promise for survival preservation and the reduction of radiation-induced morbidity. This review is an overview of the current knowledge of medulloblastoma through a molecular approach, and therapeutic prospects currently being developed in surgery, radiotherapy and targeted therapies to optimize the treatment of medulloblastoma with a multidisciplinary approach will also be discussed.