Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 196
Filter
1.
J Clin Oncol ; 40(1): 83-95, 2022 01 01.
Article in English | MEDLINE | ID: mdl-34714708

ABSTRACT

PURPOSE: To characterize the association between neurocognitive outcomes (memory and processing speed) and radiation (RT) dose to the hippocampus, corpus callosum (CC), and frontal white matter (WM) in children with medulloblastoma treated on a prospective study, SJMB03. PATIENTS AND METHODS: Patients age 3-21 years with medulloblastoma were treated at a single institution on a phase III study. The craniospinal RT dose was 23.4 Gy for average-risk patients and 36-39.6 Gy for high-risk patients. The boost dose was 55.8 Gy to the tumor bed. Patients underwent cognitive testing at baseline and once yearly for 5 years. Performance on tests of memory (associative memory and working memory) and processing speed (composite processing speed and perceptual speed) was analyzed. Mixed-effects models were used to estimate longitudinal trends in neurocognitive outcomes. Reliable change index and logistic regression were used to define clinically meaningful neurocognitive decline and identify variables associated with decline. RESULTS: One hundred and twenty-four patients were eligible for inclusion, with a median neurocognitive follow-up of 5 years. Mean right and left hippocampal doses were significantly associated with decline in associative memory in patients without posterior fossa syndrome (all P < .05). Mean CC and frontal WM doses were significantly associated with decline in both measures of processing speed (all P < .05). Median brain substructure dose-volume histograms were shifted to the right for patients with a decline in associative memory or processing speed. The odds of decline in associative memory and composite processing speed increased by 23%-26% and by 10%-15% for every 1-Gy increase in mean hippocampal dose and mean CC or frontal WM dose, respectively. CONCLUSION: Increasing RT dose to the CC or frontal WM and hippocampus is associated with worse performance on tests of processing speed and associative memory, respectively. Brain substructure-informed RT planning may mitigate neurocognitive impairment.


Subject(s)
Brain/radiation effects , Cerebellar Neoplasms/radiotherapy , Cognition/radiation effects , Cranial Irradiation , Dose Fractionation, Radiation , Medulloblastoma/radiotherapy , Radiation Dosage , Adolescent , Adolescent Behavior/radiation effects , Adolescent Development/radiation effects , Age Factors , Brain/diagnostic imaging , Brain/growth & development , Cerebellar Neoplasms/diagnostic imaging , Cerebellar Neoplasms/physiopathology , Child , Child Behavior/radiation effects , Child Development/radiation effects , Child, Preschool , Clinical Trials, Phase III as Topic , Cranial Irradiation/adverse effects , Female , Humans , Male , Medulloblastoma/diagnostic imaging , Medulloblastoma/physiopathology , Memory/radiation effects , Neuropsychological Tests , Radiotherapy Planning, Computer-Assisted , Retrospective Studies , Time Factors , Treatment Outcome , Young Adult
2.
Mol Cancer Res ; 19(11): 1831-1839, 2021 11.
Article in English | MEDLINE | ID: mdl-34330843

ABSTRACT

Medulloblastoma is the most common malignant pediatric brain tumor and there is an urgent need for molecularly targeted and subgroup-specific therapies. The stem cell factor SOX9, has been proposed as a potential therapeutic target for the treatment of Sonic Hedgehog medulloblastoma (SHH-MB) subgroup tumors, given its role as a downstream target of Hedgehog signaling and in functionally promoting SHH-MB metastasis and treatment resistance. However, the functional requirement for SOX9 in the genesis of medulloblastoma remains to be determined. Here we report a previously undocumented level of SOX9 expression exclusively in proliferating granule cell precursors (GCP) of the postnatal mouse cerebellum, which function as the medulloblastoma-initiating cells of SHH-MBs. Wild-type GCPs express comparatively lower levels of SOX9 than neural stem cells and mature astroglia and SOX9low GCP-like tumor cells constitute the bulk of both infant (Math1Cre:Ptch1lox/lox ) and adult (Ptch1LacZ/+ ) SHH-MB mouse models. Human medulloblastoma single-cell RNA data analyses reveal three distinct SOX9 populations present in SHH-MB and noticeably absent in other medulloblastoma subgroups: SOX9 + MATH1 + (GCP), SOX9 + GFAP + (astrocytes) and SOX9 + MATH1 + GFAP + (potential tumor-derived astrocytes). To functionally address whether SOX9 is required as a downstream effector of Hedgehog signaling in medulloblastoma tumor cells, we ablated Sox9 using a Math1Cre model system. Surprisingly, targeted ablation of Sox9 in GCPs (Math1Cre:Sox9lox/lox ) revealed no overt phenotype and loss of Sox9 in SHH-MB (Math1Cre:Ptch1lox/lox;Sox9lox/lox ) does not affect tumor formation. IMPLICATIONS: Despite preclinical data indicating SOX9 plays a key role in SHH-MB biology, our data argue against SOX9 as a viable therapeutic target.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/metabolism , Hedgehog Proteins/metabolism , Medulloblastoma/genetics , SOX9 Transcription Factor/metabolism , Animals , Cell Proliferation , Disease Models, Animal , Humans , Medulloblastoma/physiopathology , Mice , Signal Transduction
3.
Commun Biol ; 4(1): 552, 2021 05 11.
Article in English | MEDLINE | ID: mdl-33976373

ABSTRACT

During mammalian brain development, neural progenitor cells proliferate extensively but can ensure the production of correct numbers of various types of mature cells by balancing symmetric proliferative versus asymmetric differentiative cell divisions. This process of cell fate determination may be harnessed for developing cancer therapy. Here, we test this idea by targeting KIF20A, a mitotic kinesin crucial for the control of cell division modes, in a genetic model of medulloblastoma (MB) and human MB cells. Inducible Kif20a knockout in both normal and MB-initiating granule neuron progenitors (GNPs) causes early cell cycle exit and precocious neuronal differentiation without causing cytokinesis failure and suppresses the development of Sonic Hedgehog (SHH)-activated MB. Inducible KIF20A knockdown in human MB cells inhibits proliferation both in cultures and in growing tumors. Our results indicate that targeting the fate specification process of nascent daughter cells presents a novel avenue for developing anti-proliferation treatment for malignant brain tumors.


Subject(s)
Kinesins/metabolism , Medulloblastoma/metabolism , Neural Stem Cells/metabolism , Animals , Cell Cycle/genetics , Cell Differentiation/physiology , Cell Proliferation/physiology , Cerebellar Neoplasms/genetics , Cerebellar Neoplasms/pathology , Hedgehog Proteins/metabolism , Kinesins/genetics , Kinesins/physiology , Medulloblastoma/physiopathology , Mice , Mice, Knockout , Neural Stem Cells/physiology , Neurons/metabolism , Signal Transduction/physiology , Stem Cells/metabolism
4.
PLoS One ; 15(12): e0243272, 2020.
Article in English | MEDLINE | ID: mdl-33270750

ABSTRACT

Cluster of differentiation (CD) 166 or activated leukocyte cell adhesion molecule (ALCAM) is a transmembrane molecule known to be an intercellular adhesion factor. The expression and function of ALCAM in medulloblastoma (MB), a pediatric brain tumor with highly advanced molecular genetics, remains unclear. Therefore, this study aimed to clarify the significance and functional role of ALCAM expression in MB. ALCAM expression in 45 patients with MB was evaluated by immunohistochemical analysis of formalin-fixed paraffin-embedded clinical specimens and the relationship between ALCAM expression and pathological type/molecular subgroup, such as WNT, SHH, Group 3, and Group 4, was examined. Eight ALCAM positive (18%), seven partially positive (16%), and 30 negative (67%) cases were detected. All seven cases of the WNT molecular subgroup were ALCAM positive and ALCAM expression strongly correlated with this subgroup (P < 0.0001). In addition, functional studies using MB cell lines revealed ALCAM expression affected proliferation and migration as a positive regulator in vitro. However, ALCAM silencing did not affect survival or the formation of leptomeningeal dissemination in an orthotopic mouse model, but did induce a malignant phenotype with increased tumor cell invasion at the dissemination sites (P = 0.0029). In conclusion, our results revealed that ALCAM exhibited highly specific expression in the WNT subgroup of MB. Furthermore, we demonstrated that the cell kinetics of MB cell lines can be altered by the expression of ALCAM.


Subject(s)
Antigens, CD/metabolism , Cell Adhesion Molecules, Neuronal/metabolism , Fetal Proteins/metabolism , Medulloblastoma/metabolism , Wnt Proteins/metabolism , Activated-Leukocyte Cell Adhesion Molecule/genetics , Adolescent , Animals , Antigens, CD/physiology , Biomarkers, Tumor/metabolism , Brain Neoplasms/genetics , Cell Adhesion/genetics , Cell Adhesion Molecules, Neuronal/physiology , Cell Movement/genetics , Cell Proliferation/genetics , Cerebellar Neoplasms/genetics , Child , Child, Preschool , Female , Fetal Proteins/physiology , Gene Expression/genetics , Gene Expression Profiling , Humans , Infant , Japan/epidemiology , Male , Medulloblastoma/physiopathology , Mice , Neoplasm Invasiveness , RNA, Messenger/genetics , Wnt Proteins/genetics , Young Adult
5.
J Investig Med ; 68(6): 1179-1185, 2020 08.
Article in English | MEDLINE | ID: mdl-32690599

ABSTRACT

Medulloblastoma (MB) is the most common malignant brain tumors among children. MiR-30b-5p is a potential tumor suppressor in a variety of human cancers. However, its expression and function in MB remain poorly understood. This study aimed to investigate the expression, role and regulatory mechanism of miR-30b-5p in MB. The expression of miR-30b-5p in MB tissues and cell lines was detected by real-time PCR. The effects of miR-30b-5p on cell proliferation and apoptosis were monitored by CCK-8 (Cell Counting Kit-8) assay, colony formation assay and flow cytometry, respectively. Bioinformatics database TargetScan predicted the target genes of miR-30b-5p. The interaction between miR-30b-5p and MYB proto-oncogene Like 2 (MYBL2) was determined by luciferase reporter gene assay. We demonstrated that the expression of miR-30b-5p was significantly downregulated in MB. Upregulated miR-30b-5p could inhibit the proliferation and induce apoptosis of MB.Moreover, overexpressed miR-30b-5p could increase the expression of BAX but decrease that of Bcl-2. Downregulated miR-30b-5p exerted the opposite effect. MYBL2 was proved to be the target gene of miR-30b-5p and was negatively regulated by miR-30b-5p. These results indicate that miR-30b-5p inhibits the progression of MB via targeting the expression of MYBL2.


Subject(s)
Apoptosis , Brain Neoplasms/physiopathology , Cell Cycle Proteins/metabolism , Cell Proliferation/physiology , Medulloblastoma/physiopathology , Trans-Activators/metabolism , Apoptosis/genetics , Brain Neoplasms/genetics , Brain Neoplasms/pathology , Cell Line, Tumor , Down-Regulation , Humans , Medulloblastoma/genetics , Medulloblastoma/pathology , MicroRNAs/genetics , MicroRNAs/metabolism , Proto-Oncogene Mas , RNA/metabolism , Real-Time Polymerase Chain Reaction , Transfection
6.
J Pediatr ; 223: 141-147.e4, 2020 08.
Article in English | MEDLINE | ID: mdl-32532646

ABSTRACT

OBJECTIVE: To examine the contribution of anesthesia exposure during treatment for childhood medulloblastoma to neurocognitive outcomes 3 years after tumor diagnosis. STUDY DESIGN: In this retrospective study, anesthesia data were abstracted from medical records for 111 patients treated with risk-adapted protocol therapy at St Jude Children's Research Hospital. Neurocognitive testing data were obtained for 90.9% of patients. RESULTS: For the 101 patients (62.4% male) who completed testing, mean age at diagnosis was 10.1 years, and 74.3% were staged to have average-risk disease. Anesthesia exposure during treatment ranged from 1 to 52 events (mean = 19.9); mean cumulative duration per patient was 21.1 hours (range 0.7-59.7). Compared with normative expectations (16%), the group had a significantly greater frequency of at-risk scores (<1 SD) on measures of intelligence (28.7%), attention (35.2%), working memory (26.6%), processing speed (46.7%), and reading (25.8%). Including anesthesia exposure duration to linear regression models accounting for age at diagnosis, treatment intensity, and baseline IQ significantly increased the predicted variance for intelligence (r2 = 0.59), attention (r2 = 0.29), working memory (r2 = 0.31), processing speed (r2 = 0.44), and reading (r2 = 0.25; all P values <.001). CONCLUSIONS: In survivors of childhood medulloblastoma, a neurodevelopmentally vulnerable population, greater exposure to anesthesia significantly and independently predicts deficits in neurocognitive and academic functioning. When feasible, anesthesia exposure during treatment should be reduced.


Subject(s)
Anesthesia/methods , Attention/physiology , Cerebellar Neoplasms/therapy , Cognition Disorders/etiology , Medulloblastoma/therapy , Memory, Short-Term/physiology , Precursor Cell Lymphoblastic Leukemia-Lymphoma/therapy , Adolescent , Cerebellar Neoplasms/complications , Cerebellar Neoplasms/physiopathology , Child , Child, Preschool , Cognition Disorders/diagnosis , Cognition Disorders/physiopathology , Combined Modality Therapy/methods , Female , Humans , Male , Medulloblastoma/complications , Medulloblastoma/physiopathology , Mental Status and Dementia Tests , Precursor Cell Lymphoblastic Leukemia-Lymphoma/complications , Precursor Cell Lymphoblastic Leukemia-Lymphoma/physiopathology , Prognosis , Retrospective Studies , Risk Factors , Young Adult
7.
PLoS One ; 15(1): e0227693, 2020.
Article in English | MEDLINE | ID: mdl-31971950

ABSTRACT

Young children with brain tumours are at high risk of developing treatment-related sequelae. We aimed to assess neuropsychological outcomes 5 years after treatment. This cross-sectional study included children under 4 years of age with medulloblastoma (MB) or ependymoma (EP) enrolled in the German brain tumour trials HIT2000 and HIT-REZ2005. Testing was performed using the validated Wuerzburg Intelligence Diagnostics (WUEP-D), which includes Kaufman-Assessment-Battery, Coloured Progressive Matrices, Visual-Motor Integration, finger tapping "Speed", and the Continuous Performance Test. Of 104 patients in 47 centres, 72 were eligible for analyses. We assessed whether IQ was impacted by disease extent, disease location, patient age, gender, age at surgery, and treatment (chemotherapy with our without craniospinal irradiation [CSI] or local radiotherapy [LRT]). Median age at surgery was 2.3 years. Testing was performed at a median of 4.9 years after surgery. Patients with infratentorial EPs (treated with LRT) scored highest in fluid intelligence (CPM 100.9±16.9, mean±SD); second best scores were achieved by patients with MB without metastasis treated with chemotherapy alone (CPM 93.9±13.2), followed by patients with supratentorial EPs treated with LRT. In contrast, lowest scores were achieved by patients that received chemotherapy and CSI, which included children with metastasised MB and those with relapsed MB M0 (CPM 71.7±8.0 and 73.2±21.8, respectively). Fine motor skills were reduced in all groups. Multivariable analysis revealed that type of treatment had an impact on IQ, but essentially not age at surgery, time since surgery or gender. Our results confirm previous reports on the detrimental effects of CSI in a larger cohort of children. Comparable IQ scores in children with MB treated only with chemotherapy and in children with EP suggest that this treatment strategy represents an attractive option for children who have a high chance to avoid application of CSI. Longitudinal follow-up examinations are warranted to assess long-term neuropsychological outcomes.


Subject(s)
Brain Neoplasms/therapy , Ependymoma/therapy , Medulloblastoma/therapy , Brain Neoplasms/pathology , Brain Neoplasms/physiopathology , Child , Child, Preschool , Cohort Studies , Combined Modality Therapy , Craniospinal Irradiation/adverse effects , Cross-Sectional Studies , Ependymoma/pathology , Ependymoma/physiopathology , Female , Follow-Up Studies , Germany , Humans , Infant , Intelligence , Male , Medulloblastoma/physiopathology , Medulloblastoma/psychology , Motor Skills , Multivariate Analysis , Neuropsychological Tests , Treatment Outcome
8.
Gene Expr Patterns ; 34: 119068, 2019 12.
Article in English | MEDLINE | ID: mdl-31437514

ABSTRACT

Cerebellar granule cell precursors (GCPs) and granule cells (GCs) constitute a good model system to investigate proliferation of neural precursors and differentiation of neurons. During development, GCPs proliferate in the outer external granule cell layer (outer EGL) and then exit the cell cycle in the inner EGL to become GCs, which inwardly migrate to the inner granule cell layer (IGL). Misregulation of GCP proliferation or GC differentiation leads to maldevelopment of the cerebellum and the formation of a cerebellar tumor, medulloblastoma. Despite many efforts in this field, the mechanisms underlying GC development remain elusive. In this study, we performed detailed immunostaining in the developing cerebellum, with particular focus on GCPs and GCs, looking at several transcription factors, signaling molecules, cell cycle regulators, some of which are known to regulate neural development. Interestingly, we found distinct distribution patterns of certain proteins within the outer and inner EGL, suggesting the existence of subpopulations of GCPs and GCs in those layers. This study provides a basis for future studies on the cerebellar GC development and medulloblastoma.


Subject(s)
Cerebellum/metabolism , Neurons/metabolism , Transcription Factors/metabolism , Animals , Basic Helix-Loop-Helix Transcription Factors/metabolism , Cell Cycle , Cell Differentiation/physiology , Cell Division , Cell Proliferation , Immunohistochemistry/methods , Ki-67 Antigen/metabolism , Medulloblastoma/metabolism , Medulloblastoma/physiopathology , Mice , Mice, Inbred ICR , Neurogenesis/physiology , Signal Transduction
10.
Psychooncology ; 28(1): 131-138, 2019 01.
Article in English | MEDLINE | ID: mdl-30315720

ABSTRACT

OBJECTIVE: Impaired neurocognitive function (NCF) is a well-established consequence of pediatric medulloblastoma (MB) and its treatments. However, the frequency and features of neurocognitive dysfunction in adult-onset MB patients are largely unknown. METHODS: Adult patients (≥ 18 years) with MB who had received formal neurocognitive evaluation (N = 27) were identified. Demographic, medical, and treatment histories were extracted from the medical record. Lesion properties on MRI were analyzed and used to evaluate lesion-symptom mapping further. Demographically adjusted z-scores were calculated for each neurocognitive test and used to assess impairment frequency. Regression analyses were conducted to identify clinical and paraclinical factors associated with impaired NCF. RESULTS: Mean age of the patient sample was 33 years (SD = 11) at the time of MB diagnosis. Prior therapy included surgical resection (89%), radiation (70%), and chemotherapy (26%). A significant proportion of patients were impaired on tests of verbal learning and memory (32%), executive function (29%), and naming (18%). Age, education, lesion size, time from surgery, and number of chemotherapy cycles had the greatest contribution to test performance in random-forest regression models. CONCLUSION: This study identifies frequent impairment of NCF in adult patients with MB, particularly in the domains of learning and memory and executive function. Neurocognitive impairment is influenced by patients' demographic, disease, and treatment history. Further study is warranted to characterize the clinical impact of adult MB more fully.


Subject(s)
Cerebellar Neoplasms/physiopathology , Cognitive Dysfunction/ethnology , Medulloblastoma/physiopathology , Adult , Cerebellar Neoplasms/complications , Cognition Disorders/etiology , Cognitive Dysfunction/psychology , Executive Function , Female , Humans , Learning , Male , Medulloblastoma/complications , Memory/physiology , Neuropsychological Tests , Young Adult
11.
J Neurooncol ; 140(2): 209-224, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30132166

ABSTRACT

BACKGROUND: Group 3 tumors account for approximately 25-30% of medulloblastomas and have the worst prognosis. UAB30 is a novel synthetic rexinoid shown to have limited toxicities in humans and significant efficacy in the pediatric neuroectodermal tumor, neuroblastoma. We hypothesized that treatment with UAB30 would decrease tumorigenicity in medulloblastoma patient-derived xenografts (PDXs). METHODS: Three group 3 medulloblastoma PDXs (D341, D384 and D425) were utilized. Cell viability, proliferation, migration and invasion assays were performed after treatment with UAB30 or 13-cis-retinoic acid (RA). Cell cycle analysis was completed using flow cytometry. A flank model, a cerebellar model, and a model of leptomeningeal metastasis using human medulloblastoma PDX cells was used to assess the in vivo effects of UAB30 and RA. RESULTS: UAB30 treatment led to cell differentiation and decreased medulloblastoma PDX cell viability, proliferation, migration and invasion and G1 cell cycle arrest in all three PDXs similar to RA. UAB30 and RA treatment of mice bearing medulloblastoma PDX tumors resulted in a significant decrease in tumor growth and metastasis compared to vehicle treated animals. CONCLUSIONS: UAB30 decreased viability, proliferation, and motility in group 3 medulloblastoma PDX cells and significantly decreased tumor growth in vivo in a fashion similar to RA, suggesting that further investigations into the potential therapeutic application of UAB30 for medulloblastoma are warranted.


Subject(s)
Antineoplastic Agents/pharmacology , Carcinogenesis/drug effects , Cerebellar Neoplasms/drug therapy , Fatty Acids, Unsaturated/pharmacology , Medulloblastoma/drug therapy , Meningeal Carcinomatosis/drug therapy , Naphthalenes/pharmacology , Animals , Carcinogenesis/pathology , Cells, Cultured , Cerebellar Neoplasms/pathology , Cerebellar Neoplasms/physiopathology , Female , Humans , Isotretinoin/pharmacology , Medulloblastoma/pathology , Medulloblastoma/physiopathology , Meningeal Carcinomatosis/pathology , Meningeal Carcinomatosis/physiopathology , Mice, Nude , Neoplasm Transplantation , Random Allocation , Retinoid X Receptors/agonists , Retinoid X Receptors/metabolism
12.
J Cell Biochem ; 119(12): 9866-9877, 2018 12.
Article in English | MEDLINE | ID: mdl-30156009

ABSTRACT

Medulloblastoma is a primitive neuroectodermal-derived brain tumor and the most common malignant brain tumor in children. Triptolide (TPL) is the major active component extracted from Tripterygium wilfordii Hook F. This study aimed to explore the effects of TPL on medulloblastoma cell proliferation, migration, and apoptosis, as well as the underlying possible molecular mechanism. Viability, proliferation, and apoptosis of Daoy cells were measured using cell counting kit-8 assay, 5-bromo-2'-deoxyuridine incorporation assay, and Guava Nexin assay, respectively. Cell migration was detected using two-chamber transwell assay and wound healing assay. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to determine the relative expression of microRNA-138 (miR-138) in Daoy cells. Cell transfection was used to change the expression of miR-138 in cells. Western blot analysis was used to analyze the expression of key factors involved in cell apoptosis, cell migration, the phosphatidylinositol 3-kinase (PI3K)/protein kinase 3 (AKT) pathway, and the Notch pathway in Daoy cells. We found that TPL significantly inhibited the viability, proliferation, and migration of Daoy cells but promoted Daoy cell apoptosis. The expression levels of matrix metalloproteinases (MMP)-2 and MMP-9 after TPL treatment were decreased. The expression of miR-138 in Daoy cells after TPL treatment was increased. Suppression of miR-138 obviously reversed the TPL-induced Daoy cell proliferation, migration inhibition, and cell apoptosis enhancement, as well as the inactivation of the PI3K/AKT and Notch pathways. Cyclin-dependent kinase 6 (CDK6) was a direct target gene of miR-138, which might be involved in the antitumor effects of TPL on Daoy cells. In conclusion, our study verified that TPL exerted anticancer effects on medulloblastoma cells possibly via upregulating miR-138 and inactivating the PI3K/AKT and Notch pathways.


Subject(s)
Cell Proliferation , Cerebellar Neoplasms/drug therapy , Diterpenes/pharmacology , Medulloblastoma/drug therapy , MicroRNAs/genetics , Phenanthrenes/pharmacology , Signal Transduction , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Cell Line, Tumor , Cell Movement , Cerebellar Neoplasms/genetics , Cerebellar Neoplasms/metabolism , Cerebellar Neoplasms/physiopathology , Diterpenes/therapeutic use , Epoxy Compounds/pharmacology , Epoxy Compounds/therapeutic use , Gene Expression Regulation, Neoplastic , HEK293 Cells , Humans , Medulloblastoma/genetics , Medulloblastoma/metabolism , Medulloblastoma/physiopathology , Phenanthrenes/therapeutic use , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Receptors, Notch/metabolism
13.
World Neurosurg ; 117: 344-349, 2018 Sep.
Article in English | MEDLINE | ID: mdl-29966776

ABSTRACT

BACKGROUND: Lhermitte-Duclos disease is an extremely rare pathologic entity characterized by a cerebellar mass composed of enlarged cerebellar folia containing abnormal ganglion cells. This entity usually presents in young and middle-aged adults and rarely in children. There is no study in the literature analyzing the long-term clinical course of this disease to assess the behavior primarily because of its rarity. CASE DESCRIPTION: We present our experience with a 7-year-old patient of Lhermitte-Duclos disease who was followed up for 5 years and found to have progressed to bilateral World Health Organization grade IV medulloblastoma. This case denotes the malignant potential of this rare disorder. CONCLUSIONS: LDD is seen rarely and demands a high degree of suspicion in patients presenting with cerebellar mass and/or imaging characteristics. It is prudent to keep these patients in close follow-up for early detection of malignant transformation.


Subject(s)
Cerebellar Neoplasms/physiopathology , Hamartoma Syndrome, Multiple/physiopathology , Medulloblastoma/physiopathology , Cerebellar Neoplasms/diagnostic imaging , Cerebellar Neoplasms/pathology , Cerebellar Neoplasms/therapy , Child , Disease Progression , Hamartoma Syndrome, Multiple/diagnostic imaging , Hamartoma Syndrome, Multiple/drug therapy , Humans , Male , Medulloblastoma/diagnostic imaging , Medulloblastoma/pathology , Medulloblastoma/therapy
14.
Elife ; 62017 11 23.
Article in English | MEDLINE | ID: mdl-29168692

ABSTRACT

Treatment for medulloblastoma, the most common malignant brain tumor in children, remains limited to surgical resection, radiation, and traditional chemotherapy; with long-term survival as low as 50-60% for Sonic Hedgehog (Shh)-type medulloblastoma. We have shown that the transcription factor Atonal homologue 1 (Atoh1) is required for Shh-type medulloblastoma development in mice. To determine whether reducing either Atoh1 levels or activity in tumors after their development is beneficial, we studied Atoh1 dosage and modifications in Shh-type medulloblastoma. Heterozygosity of Atoh1 reduced tumor occurrence and prolonged survival. We discovered tyrosine 78 of Atoh1 is phosphorylated by a Jak2-mediated pathway only in tumor-initiating cells and in human SHH-type medulloblastoma. Phosphorylation of tyrosine 78 stabilizes Atoh1, increases Atoh1's transcriptional activity, and is independent of canonical Jak2 signaling. Importantly, inhibition of Jak2 impairs tyrosine 78 phosphorylation and tumor growth in vivo. Taken together, inhibiting Jak2-mediated tyrosine 78 phosphorylation could provide a viable therapy for medulloblastoma.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/metabolism , Carcinogenesis , Janus Kinase 2/metabolism , Medulloblastoma/pathology , Medulloblastoma/physiopathology , Protein Processing, Post-Translational , Animals , Cell Line, Tumor , Disease Models, Animal , Humans , Mice , Phosphorylation
15.
Genes Dev ; 31(17): 1738-1753, 2017 09 01.
Article in English | MEDLINE | ID: mdl-28971956

ABSTRACT

Medulloblastoma is the most common solid primary brain tumor in children. Remarkable advancements in the understanding of the genetic and epigenetic basis of these tumors have informed their recent molecular classification. However, the genotype/phenotype correlation of the subgroups remains largely uncharacterized. In particular, the metabolic phenotype is of great interest because of its druggability, which could lead to the development of novel and more tailored therapies for a subset of medulloblastoma. p73 plays a critical role in a range of cellular metabolic processes. We show overexpression of p73 in a proportion of non-WNT medulloblastoma. In these tumors, p73 sustains cell growth and proliferation via regulation of glutamine metabolism. We validated our results in a xenograft model in which we observed an increase in survival time in mice on a glutamine restriction diet. Notably, glutamine starvation has a synergistic effect with cisplatin, a component of the current medulloblastoma chemotherapy. These findings raise the possibility that glutamine depletion can be used as an adjuvant treatment for p73-expressing medulloblastoma.


Subject(s)
Cerebellar Neoplasms/diet therapy , Cerebellar Neoplasms/physiopathology , Glutamine/metabolism , Medulloblastoma/diet therapy , Medulloblastoma/physiopathology , Tumor Protein p73/genetics , Tumor Protein p73/metabolism , AMP-Activated Protein Kinases/metabolism , Animals , Cell Line, Tumor , Cell Proliferation/genetics , Disease Models, Animal , Gene Expression Regulation, Neoplastic/genetics , Glutaminase/genetics , Glutaminase/metabolism , Heterografts , Humans , Mice , Mitochondria/genetics , Mitochondria/metabolism , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Survival Analysis , TOR Serine-Threonine Kinases/metabolism , Treatment Outcome , Tumor Cells, Cultured
16.
J AAPOS ; 21(5): 375-379, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28867398

ABSTRACT

PURPOSE: To describe the clinical characteristics and visual and ocular motor outcomes of a large cohort of pediatric patients treated for tumors of the posterior cranial fossa. METHODS: The medical records of all patients with posterior fossa tumors evaluated by the ophthalmology services at two large tertiary care academic hospitals between 2005 and 2011 were reviewed retrospectively. Data abstracted for each study patient included demographic information, presenting signs and symptoms, pathologic diagnosis, and results of the most recent ophthalmology examination. RESULTS: A total of 139 patients were included. Visual outcomes were categorized as "good" (bilateral acuity of 20/20-20/40) in 101 patients (72.7%), "fair" (<20/40-20/200 in one or both eyes) in 12 patients (8.6%), or "poor" (<20/200 in one or both eyes) in 9 patients (6.5%). Patients with medulloblastoma and ependymoma had a significantly greater risk of a poor or fair visual outcome than those with juvenile pilocytic astrocytoma (both P < 0.05), independent of age and sex. Thirty-two patients (23.0%) developed nystagmus, and 59 patients (42.4%) developed strabismus. Twenty-four patients (17.3%) underwent eye muscle surgery for persistent strabismus. CONCLUSIONS: The majority of patients had good visual outcomes, although ocular motor abnormalities were common. Tumor type was a significant risk factor for permanent vision loss.


Subject(s)
Astrocytoma/therapy , Ependymoma/therapy , Infratentorial Neoplasms/therapy , Medulloblastoma/therapy , Oculomotor Muscles/physiopathology , Visual Acuity/physiology , Adolescent , Astrocytoma/diagnostic imaging , Astrocytoma/physiopathology , Child , Child, Preschool , Ependymoma/diagnostic imaging , Ependymoma/physiopathology , Female , Humans , Infant , Infratentorial Neoplasms/diagnostic imaging , Infratentorial Neoplasms/physiopathology , Magnetic Resonance Imaging , Male , Medulloblastoma/diagnostic imaging , Medulloblastoma/physiopathology , Nystagmus, Pathologic/physiopathology , Nystagmus, Pathologic/surgery , Retrospective Studies , Strabismus/physiopathology , Strabismus/surgery
17.
Semin Pediatr Neurol ; 24(2): 100-103, 2017 05.
Article in English | MEDLINE | ID: mdl-28941523

ABSTRACT

Tumors of the posterior fossa represent the most common solid malignancy of childhood and can affect the visual system in several ways. This article outlines the relevant visual anatomy affected by these tumors and reviews the visual and oculomotor outcomes associated with the following 3 most common tumor types-medulloblastoma, juvenile pilocytic astrocytoma, and ependymoma. The available data suggest that the rate of permanent vision loss is low (5.9%-8.3%), with patients having juvenile pilocytic astrocytoma demonstrating the best outcomes. The rate of long-term strabismus (25%-29.1%) and nystagmus (12.5%-18%) is higher and associated with significant morbidity.


Subject(s)
Eye Movements , Infratentorial Neoplasms/physiopathology , Infratentorial Neoplasms/therapy , Visual Perception , Astrocytoma/epidemiology , Astrocytoma/pathology , Astrocytoma/physiopathology , Astrocytoma/therapy , Child , Ependymoma/epidemiology , Ependymoma/pathology , Ependymoma/physiopathology , Ependymoma/therapy , Eye Movements/physiology , Humans , Infratentorial Neoplasms/epidemiology , Infratentorial Neoplasms/pathology , Medulloblastoma/epidemiology , Medulloblastoma/pathology , Medulloblastoma/physiopathology , Medulloblastoma/therapy , Visual Perception/physiology
18.
Biochem Pharmacol ; 138: 1-6, 2017 08 15.
Article in English | MEDLINE | ID: mdl-28389227

ABSTRACT

Sonic hedgehog (Shh) signaling plays a key role in regulation of normal development. The negative feedback mechanism mediated by the transcriptional factor, Gli3, acts to finely tune Shh signaling, providing tight control of normal developmental processes. Hyperactivation of Shh signaling often leads to many human malignancies, including basal cell carcinoma and medulloblastoma (MB). However, how tumor cells sustain the aberrant activation of Shh signaling is still not completely understood. We recently revealed that during MB formation, tumor cells express Nestin, a type VI intermediate filament protein, which maintains uncontrolled Shh signaling by abolishing negative feedback by Gli3. Therefore, Nestin expression is a necessary step for MB formation. These findings highlight the novel function of Nestin in regulating Shh signaling, as well as the important role of a disrupted negative feedback mechanism in MB tumorigenesis. Further, restoration of the intrinsic negative feedback by repressing Nestin expression represents a promising approach to treat MB as well as other Shh signaling associated malignancies.


Subject(s)
Antineoplastic Agents/therapeutic use , Cerebellar Neoplasms/drug therapy , Hedgehog Proteins/metabolism , Kruppel-Like Transcription Factors/metabolism , Medulloblastoma/drug therapy , Models, Biological , Nerve Tissue Proteins/metabolism , Nestin/antagonists & inhibitors , Animals , Cerebellar Neoplasms/metabolism , Cerebellar Neoplasms/pathology , Cerebellar Neoplasms/physiopathology , Disease Progression , Feedback, Physiological/drug effects , Humans , Medulloblastoma/metabolism , Medulloblastoma/pathology , Medulloblastoma/physiopathology , Molecular Targeted Therapy , Neoplasm Proteins/antagonists & inhibitors , Neoplasm Proteins/metabolism , Nerve Tissue Proteins/antagonists & inhibitors , Nestin/metabolism , Signal Transduction/drug effects , Tumor Burden , Zinc Finger Protein Gli3
19.
J Pediatr ; 185: 173-180.e3, 2017 06.
Article in English | MEDLINE | ID: mdl-28187964

ABSTRACT

OBJECTIVE: To compare cerebral perfusion and diffusion in survivors of childhood posterior fossa brain tumor with neurologically normal controls and correlate differences with cognitive dysfunction. STUDY DESIGN: We analyzed retrospectively arterial spin-labeled cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) in 21 patients with medulloblastoma (MB), 18 patients with pilocytic astrocytoma (PA), and 64 neurologically normal children. We generated ANCOVA models to evaluate treatment effects on the cerebral cortex, thalamus, caudate, putamen, globus pallidus, hippocampus, amygdala, nucleus accumbens, and cerebral white matter at time points an average of 5.7 years after original diagnosis. A retrospective review of patient charts identified 12 patients with neurocognitive data and in whom the relationship between IQ and magnetic resonance imaging variables was assessed for each brain structure. RESULTS: Patients with MB (all treated with surgery, chemotherapy, and radiation) had significantly lower global CBF relative to controls (10%-23% lower, varying by anatomic region, all adjusted P?

Subject(s)
Brain/pathology , Cerebrovascular Circulation/physiology , Infratentorial Neoplasms/physiopathology , Adolescent , Astrocytoma/physiopathology , Astrocytoma/therapy , Brain/diagnostic imaging , Case-Control Studies , Child , Child, Preschool , Cross-Sectional Studies , Female , Humans , Infratentorial Neoplasms/therapy , Magnetic Resonance Imaging , Male , Medulloblastoma/physiopathology , Medulloblastoma/therapy , Neuropsychological Tests , Regional Blood Flow/physiology , Retrospective Studies , Young Adult
20.
Pediatr Blood Cancer ; 64(6)2017 06.
Article in English | MEDLINE | ID: mdl-27917595

ABSTRACT

PURPOSE: Medulloblastoma is the most prevalent childhood brain cancer. Children with medulloblastoma typically receive a combination of surgery, radiation, and chemotherapy. The survival rate is high but survivors often have sequelae from radiotherapy of the entire developing brain and spinal cord. Ongoing genetic studies have suggested that decreasing the dose of radiation might be possible among children with favorable molecular variants; however, this may result in an increased disease recurrence. As such, there is a need to investigate the nature of trade-offs that individuals are willing to make regarding the treatment of medulloblastoma. METHOD: We used best-worst scaling to estimate the importance of attributes affecting the general public's decision making around the treatment of medulloblastoma. After conducting focus groups, we selected three relevant attributes: (1) the accuracy of the genetic test; (2) the probability of serious adverse effects of the treatment(s); and (3) the survival rate. Using the paired method, we applied a conditional logit model to estimate preferences. RESULTS: In total, 3,006 respondents (51.3% female) with an average age of 43 years answered the questionnaires. All coefficients were statistically significantly different from zero and the attribute levels of adverse effects and the survival rate had the most impact on individuals' stated decision making. CONCLUSION: Overall, respondents showed high sensitivity to children experiencing disability particularly in the setting of a good prognosis. However, among children with poor prognostic molecular variants, participants showed tolerance about having a child with mild and partial disability compared to a low rate of survival.


Subject(s)
Brain Neoplasms , Medulloblastoma , Quality of Life , Adult , Age Factors , Brain Neoplasms/mortality , Brain Neoplasms/physiopathology , Brain Neoplasms/therapy , Disease-Free Survival , Female , Humans , Male , Medulloblastoma/mortality , Medulloblastoma/physiopathology , Medulloblastoma/therapy , Middle Aged , Risk Factors , Socioeconomic Factors , Survival Rate
SELECTION OF CITATIONS
SEARCH DETAIL