Atypical teratoid/rhabdoid tumor (ATRT) is a highly malignant CNS neoplasm whichprimarily occurs in children under three years of age. Due to poor outcomes with intense and toxicmultimodality treatment, new therapies are urgently needed. Histone deacetylase inhibitors (HDIs)have been evaluated as novel agents for multiple malignancies and have been shown to function asradiosensitizers. They act as epigenetic modifiers and lead to re-expression of inappropriatelyrepressed genes, proteins, and cellular functions. Due to the underlying chromatin remodeling genemutation in ATRT, HDIs are ideal candidates for therapeutic evaluation. To evaluate the role of HDIsagainst ATRT in vitro, we assessed the effect of drug treatment on proliferation, apoptosis, and geneexpression. Additionally, we examined HDI pretreatment as a radiosensitization strategy for ATRT.MTS and clonogenic assays demonstrated that HDI treatment significantly reduces the proliferativecapacity of BT-12 and BT-16 ATRT cells. Also, the HDI SNDX-275 was able to induce apoptosis in bothcell lines and induced p21Waf1/Cip1 protein expression as measured by Western blot. Evaluation ofdifferential gene expression by microarray and pathway analysis after HDI treatment demonstratedalterations of several key ATRT cellular functions. Finally, we showed that HDI pretreatmenteffectively potentiates the effect of ionizing radiation on ATRT cells as measured by clonogenic assay.These findings suggest that the addition of HDIs to ATRT therapy may prove beneficial, especiallywhen administered in combination with current treatment modalities such as radiation.
Histone deacetylase inhibition decreases proliferation and potentiates the effect of ionizing radiation in atypical teratoid/rhabdoid tumor cells.
Specimen part, Cell line
View SamplesMost human tumors have abnormal numbers of chromosomes, a condition known as aneuploidy. The mitotic checkpoint is an important mechanism that prevents aneuploidy through restraining the activity of the anaphase-promoting complex (APC). USP44 was identified as a key regulator of APC activation that maintains the association of MAD2 with the APC co-activator Cdc20. However, the physiological importance of USP44 and its impact on cancer biology are unknown. Here, we show that USP44 is required to prevent tumors in mice and is frequently down-regulated in human lung cancer. USP44 inhibits chromosome segregation errors independently of its role in the mitotic checkpoint by regulating proper centrosome separation, positioning, and mitotic spindle geometry, functions that require direct binding to the centriole protein, centrin. These data reveal a new role for the ubiquitin system in mitotic spindle regulation and underscore the importance of USP44 in the pathogenesis of human cancer.
USP44 regulates centrosome positioning to prevent aneuploidy and suppress tumorigenesis.
Sex, Disease, Disease stage
View SamplesThe characteristics of immune cells infiltrating pediatric brain tumors is largely unexplored. A better understanding of these characteristics will provide a foundation for development of immunotherapy for pediatric brain tumors.
Characterization of distinct immunophenotypes across pediatric brain tumor types.
Specimen part, Disease, Disease stage
View SamplesCongenital glioblastoma multiforme (cGBM) historically has been considered an aggressive tumor of infancy requiring extensive chemotherapy to achieve cure. We report on 4 patients at our institution with cGBMs who were treated with surgery and chemotherapy (carboplatin and etoposide every 21 days for 2-6 cycles). Four of four patients are progression free at a median time of 27.5 months (22-103 months). To characterize the molecular biology of cGBM, we compared the gene expression profiles of 3 cGBMs to 12 pediatric and 6 primary adult glioblastomas collected at our institution. Unsupervised hierarchical clustering showed cGBMs grouped together with other high-grade gliomas. cGBMs demonstrated marked similarity to both pediatric and adult GBMs, with only a total of 31 differentially expressed genes identified (FDR < 0.05). Unique molecular features of congenital GBMs identified included over-expression of multiple genes involved in glucose metabolism and tissue hypoxia pathways. Four tyrosine kinases were also mong the up-regulated genes (RET, RASGRF2, EFNA5, ALK). Thus, at our institution congenital GBMs, while similar both histologically and molecularly to other GBMs, appear to have a good prognosis with surgery in combination with relatively moderate chemotherapy. Further study is needed to determine if the few gene expression differences that were identified may contribute to the better survival seen in these tumors compared to pediatric or adult GBMs.
Clinical and molecular characteristics of congenital glioblastoma.
Sex, Disease, Disease stage
View SamplesEpendymoma, the 3rd most common brain tumor in children, recurs in approximately 50% of patients. There is currently no robust marker that predicts for recurrence, which is a significant clinical problem
Immune gene and cell enrichment is associated with a good prognosis in ependymoma.
Specimen part
View SamplesRhabdoid tumors (RTs) are aggressive tumors of early childhood that occur most often in brain (AT/RTs) or kidney (KRTs). Regardless of location, they are characterized by loss of functional SMARCB1 protein, a component of the SWI/SNF chromatin remodeling complex. The aim of this study was to determine genes and biological process dysregulated in common to both AT/RTs and KRTs. Gene expression for AT/RTs was compared to that of other brain tumors and normal brain using microarray data from our lab. Similar analysis was performed for KRTs and other kidney tumors and normal kidney using data from GEO. Dysregulated genes common to both analyses were analyzed for functional significance. Unsupervised hierarchical clustering of RTs identified 3 major subsets: 2 comprised of AT/RTs, and 1 of KRTs. Compared to other tumors, 1187, 663 and 539 genes were dysregulated in each subset, respectively. Only 14 dysregulated genes were common to all 3 subsets. Compared to normal tissue, 5209, 4275 and 2841 genes were dysregulated in each subset, with an overlap of 610 dysregulated genes. Among these genes, processes associated with cell proliferation, MYC activation, and epigenetic dysregulation were common to all 3 RT subsets. The low overlap of dysregulated genes in AT/RTs and KRTs suggests that factors in addition to SMARCB1 loss play a role in determining subsequent gene expression. Drugs which target cell cycle or epigenetic genes may be useful in all RTs. Additionally, targeted therapies tailored to specific RT subset molecular profiles should be considered.
Pediatric rhabdoid tumors of kidney and brain show many differences in gene expression but share dysregulation of cell cycle and epigenetic effector genes.
Specimen part
View SamplesSurvival in the majority of high grade astrocytoma (HGA) patients is very poor, with only a rare population of long-term survivors. A better understanding of the biological factors associated with long-term survival in HGA would aid development of more effective therapy and prognostication.
Increased immune gene expression and immune cell infiltration in high-grade astrocytoma distinguish long-term from short-term survivors.
Specimen part
View SamplesMolecular profiling of tumors has proven a valuable tool for identification of prognostic and diagnostic subgroups in medulloblastomas, glioblastomas and other cancers. However, the molecular landscape of atypical teratoid / rhabdoid tumors (AT/RTs) remains largely unexplored. To address this issue, we used microarrays to measure the gene expression profiles of 18 AT/RTs, and performed unsupervised hierarchical clustering to determine molecularly similar subgroups. Four major subgroups (clusters) were identified. These did not conform to gender, tumor location, or presence of monosomy 22. Clusters showed distinct gene signatures and differences in enriched biological processes, including elevated expression of choroid plexus genes in Cluster 4. In addition, survival differed significantly by cluster, with shortest survival (mean 4.7 months) in both Clusters 3 and 4 compared to Clusters 1 and 2 (mean 28.1 months). Analysis showed that multiple bone morphogenetic protein (BMP) pathway genes were up-regulated in the short survival clusters, with BMP4 showing the most significant up-regulation (270-fold). Thus, high expression of BMP pathway genes was negatively associated with survival in this dataset. Our study indicates that molecular subgroups exist within AT/RTs, and that molecular profiling of these comparatively rare tumors may be of diagnostic, prognostic and therapeutic value.
High expression of BMP pathway genes distinguishes a subset of atypical teratoid/rhabdoid tumors associated with shorter survival.
Sex, Specimen part
View SamplesWe compared molecular characteristics of primary and recurrent pediatric ependymoma to identify sub-group specific differences.
Molecular sub-group-specific immunophenotypic changes are associated with outcome in recurrent posterior fossa ependymoma.
Specimen part
View SamplesInflammatory response has been identified as a molecular signature of high-risk Group A ependymoma (EPN). To better understand the biology of this phenotype and aid therapeutic development, transcriptomic data from Group A and B EPN patient tumor samples, and additional malignant and normal brain data, were analyzed to identify the mechanism underlying EPN group A inflammation.
Interleukin-6/STAT3 Pathway Signaling Drives an Inflammatory Phenotype in Group A Ependymoma.
Specimen part, Disease, Disease stage
View Samples