Project description:Neuroblastoma is an embryonal tumor arising from the neural crest. It can be mimicked in mice by neural crest-specific overepxression of oncogenes such as MYCN or mutated ALK. Expression profiling of murine neuroblastoma driven by MYCN were compared to those driven by mutated ALK and to mouse normal adrenal tissue.
Project description:Neuroblastoma is a common childhood malignant tumor of neural crest origin with remarkable heterogeneity in outcomes. Amplification of the oncogene MYCN is strongly associated with highly malignant behaviour and poor prognosis. Here, we used human ESC-derived neural crest model to recapitulate the initiation of MYCN-driven neuroblastoma and to identify MYCN downstream effectors. Our results show that induced deregulation of MYCN in human neural crest progenitor cells is sufficient to induce tumors that recapitulate the pathological and molecular features of human MYCN-amplified neuroblastoma(MNA-NB). By using this platform, we are able to identify a group of 28 genes that are associated with MYCN expression level only in MNA-NB.
Project description:Bone morphogenetic proteins (BMPs) trigger as cell-extrinsic signals the differentiation of neural crest progenitor cells to the sympathoadrenal cell lineage. Human neuroblastoma derives from aberrant neural crest progenitor cells. We here show that histone deacetylase 11 (HDAC11), the most recently identified family member with, as yet, largely unknown function, is recruited to the BMP4 gene promoter and represses its transcription in neuroblastoma. Both HDAC11 depletion and enzymatic inhibition revert the epigenetic silencing of BMP4, thereby blocking a critical oncogenic function of HDAC11. Activated BMP4 signaling through targeting of HDAC11 induces a transcriptional profile predictive of favorable prognosis for patients when expressed in the tumors, indicating that the HDAC11-BMP4 axis plays a critical role for neuroblastoma biology. Furthermore, pathway activation causes MYCN proto-oncogene repression on a molecular level and anti-proliferative effects in functional assays in neuroblastoma cell lines and primary sphere cultures as well as strongly inhibiting tumor formation and growth of subcutaneous neuroblastoma xenografts in mice. For high-risk neuroblastoma, with cure rates below 30% using current treatment strategies, our work suggests a novel targeted therapeutic approach that would reactivate the developmental pathway inducing normal differentiation of neural crest progenitor cells.
Project description:Circular RNAs (circRNAs), a noncoding RNA class originating from alternative splicing, are highly abundant in neural tissues and were shown to regulate gene expression e.g. by interacting with microRNAs and RNA-binding proteins. Neuroblastoma is an embryonal neoplasia, which arises from undifferentiated neural crest cells. Here, we aimed to explore, whether circRNAs influence the pathogenesis of high-risk neuroblastoma. We performed whole-transcriptome sequencing of 104 primary neuroblastoma samples of all risk-groups and identified 5,203 unique circRNAs involving 2,302 genes. Candidate circRNA expression did not correlate with host gene expression, indicating independent regulatory mechanisms. circRNAs were significantly downregulated in the MYCN-amplified high-risk tumors. These findings were independently reproduced in a tetracycline-inducible MYCN-overexpression system based on a non MYCN-amplified neuroblastoma cell line, suggesting that MYCN drives this global circRNA repression. We identified the RNA helicase DHX9 as a mediator of this global suppressive effect of MYCN on circRNAs. Comparing our RNA sequencing data with other cancers and controls revealed a circRNA subset specifically upregulated in neuroblastoma that included a circRNA derived from the ARID1A tumor suppressor gene. Specific circARID1A knockdown resulted in reduced proliferation, cell numbers and viability, prompted apoptosis and induced a differentiated phenotype. Neither knockdown, nor overexpression of circARID1A influenced ARID1A mRNA and protein levels significantly. To dissect the potential mode of function, we performed a pulldown assay with subsequent mass spectrometry. We identified the RNA-binding protein KHSRP as an interaction partner that participates in the mechanism of action of circARID1A. In summary, this study highlights an important role of circRNAs in neuroblastoma biology and may establish this RNA class as a future therapeutic target and biomarker.
Project description:Neural crest cells are migratory progenitor cells that contribute to nearly all tissues and organs throughout the body. Their formation, migration and differentiation are regulated by a multitude of signaling pathways, that when disrupted can lead to disorders termed neurocristopathies. While work in avian and amphibian species has revealed essential factors governing the specification and induction of neural crest cells during gastrulation and neurulation in non-mammalian species, their functions do not appear to be conserved in mice, leaving major gaps in our understanding of neural crest cell formation in mammals. Here we describe Germ Cell Nuclear Factor (GCNF/Nr6a1), an orphan nuclear receptor, as a critical regulator of neural crest cell formation in mice. Gcnf null mutant mice, exhibit a major disruption of neural crest cell formation. The purpose of this experiment is to examine gene expression changes in response to Gcnf mutation in E9.0 mouse embryos.
Project description:Neuroblastoma is an embryonal tumor arising from the neural crest. It can be mimicked in mice by neural crest-specific overepxression of oncogenes such as MYCN or mutated ALK.
Project description:Amplification of MYCN is the most prominent genetic marker of high-stage neuroblastoma, a childhood tumor originating from the neural crest. We generated a transgenic mouse with Cre-conditional induction of MYCN in dopamine beta hydroxylase expressing cells that develops murine neuroblastomas.
Project description:To confirm the neuroblastomas (NB) identity of human neuroblastomas from mouse-human neural crest chimeric mice model (CHNBs) we characterized their gene expression profiles by RNA-Seq (CHNBs MYCN+ALKF1174L; n=8). For a global comparison of gene expression profiles of CHNBs with other NB models, we further collected RNA-seq data from patient derived xenografts of neuroblastoma (PDX NBs ; MYCNamp+ALKwt PDX; n=2, and MYCNamp+ALKF1174L PDX; n=3), neuroblastomas from genetically engineered mouse model (GEMM NBs; Th-MYCN+ALKF1174L; n=3), neuroblastoma established cell lines (n=2; Kelly, MYCNamp+ALKF1174L; SH-SY5Y, MYCNwt+ ALKF1174L), human pluripotent derived human neural crest cells (hNCCs; wt hNCCs; n=2, and MYCN+ALKF1174L hNCCs, with Dox; n=2) and from hNCC xenografts (MYCN+ALKF1174L; n=5).
Project description:In neuroblastoma, amplification of the oncogenic basic helix-loop-helix (bHLH) transcription factor (TF) MYCN is the defining prognosticator of high-risk disease, occurs in one-third of neuroblastoma, and drastically reduces overall survival rates. As a proto-oncogene, targeted MYCN overexpression in peripheral neural crest is sufficient to initiate disease in mouse models. In MYCN amplified neuroblastoma, elevated expression of the factor is crucial to maintain tumor stemness and is associated with increased proliferation and aberrant cell cycle progression, as these tumors lack the ability to arrest in G1 in response to irradiation. MYCN down-regulation broadly reverses these oncogenic phenotypes in a variety of neuroblastoma models and recent thereapeutic strategies to indirectly target MYCN production or protein stability have reduced tumor growth in vivo. These observations motivate an investigation of MYCN binding in MYCN amplified tumors as it remains fundamentally unclear how elevated levels of the factor occupy the genome and alter transcriptional programs in neuroblastoma. Here we present the first dynamic chromatin and transcriptional landscape of direct MYCN perturbation in neuroblastoma. We find that at oncogenic levels, MYCN associates with E-box (CANNTG) binding motifs in an affinity dependent manner across most active cis-regulatory promoters and enhancers. MYCN shutdown globally reduces histone acetylation and transcription, consistent with prior descriptions of MYC proteins as non-linear amplifiers of gene expression. We establish that MYCN load at the promoter and proximal enhancers predicts transcriptional responsiveness to MYCN shutdown and that MYCN enhancer binding occurs prominently at the most strongly occupied and down-regulated genes, suggesting a role for these tissue specific elements in predicating MYCN responsive âtargetâ genes. At these invaded enhancers, we identify the lineage specific bHLH TWIST1 as a key collaborator and dependency of oncogenic MYCN. These data suggest that MYCN enhancer invasion helps shape transcriptional amplification of the neuroblastoma gene expression program to promote tumorigenesis. ChIP-Seq in SHEP21, BE2C, KELLY, and NGP neuroblastoma cell lines for H3K27ac, H3K4me3, RNA PolII, MYCN, BRD4, or TWIST1
Project description:Neuroblastoma is an embryonic solid tumor of neural crest origin and accounts for 11% of all cancer-related deaths in children. Novel therapeutic strategies are therefore urgently required. MYCN oncogene amplification, which occurs in 20% of neuroblastomas, is a hallmark of high risk. Here we aimed to exploit molecular mechanisms that can be pharmacologically addressed with epigenetically modifying drugs, such as histone deacetylase (HDAC) inhibitors. GRHL1, a gene critical for Drosophila neural development, belonged to the genes most strongly responding to HDAC inhibitor treatment of neuroblastoma cells in a genome- wide screen. An increase in the histone H4 pan-acetylation associated with its promoter preceded transcriptional activation. Physically adjacent, HDAC3 and MYCN co-localized to the GRHL1 promoter and repressed its transcription. High-level GRHL1 expression in primary neuroblastomas correlated on transcriptional and translational levels with favorable patient survival and established clinical and molecular markers for favorable tumor biology, including lack of MYCN amplification. Enforced GRHL1 expression in MYCN-amplified neuroblastoma cells with low endogenous GRHL1 levels abrogated anchorage-independent colony formation, inhibited proliferation and retarded xenograft growth in mice. GRHL1 regulated 170 genes genome-wide, and most were involved in pathways regulated during neuroblastomagenesis, including nervous system development, proliferation, cell-cell adhesion, cell spreading and cellular differentiation. In summary, the data presented here indicate a significant role of HDAC3 in the MYCN-mediated repression of GRHL1 and suggest drugs that block HDAC3 activity and suppress MYCN expression as promising candidates for novel treatment strategies of high-risk neuroblastoma. Twelve samples were analyzed. Each 2 replicated of paired empty vector control and GRHL1 forced expression at 3 different time points.