Project description:Ptch+/- mice, which are predisposed to SHH subgroup medulloblastoma, were mutagenised using the Sleeping Beauty transposon to identify genes which increase the frequency of medulloblastoma formation. Gene expression in tumours was assessed both to investigate their relationship to human subgroup tumours, and to identify genes where expression was altered by mutagenesis. Total RNA isolated from tumours induced by SB mutagenesis were compared to normal cerebellum, tumours induced witout SB mutagenesis, and tumours from a distinct model of disease (GTML).
Project description:Ptch+/- mice, which are predisposed to SHH subgroup medulloblastoma, were mutagenised using the Sleeping Beauty transposon to identify genes which increase the frequency of medulloblastoma formation. Gene expression in tumours was assessed both to investigate their relationship to human subgroup tumours, and to identify genes where expression was altered by mutagenesis.
Project description:Thymic lymphomas were generated by inducing Sleeping Beauty transposon mutagenesis at different stages of T-cell development. This dataset includes exon array results from 14 tumor samples from two different Sleeping Beauty models of T-ALL (7 Vav-SB and 7 CD4-SB samples).
Project description:While medulloblastoma, a pediatric tumor of the cerebellum, is characterized by aberrations in developmental pathways, the majority of genetic determinants remain unknown. An unbiased Sleeping Beauty transposon screen revealed MyoD as a putative medulloblastoma tumor suppressor. This was unexpected, as MyoD is a muscle differentiation factor and not previously known to be expressed in cerebellum or medulloblastoma. In response to deletion of one allele of MyoD, two other Sonic hedgehog-driven mouse medulloblastoma models showed accelerated tumor formation and death, confirming MyoD as a tumor suppressor in these models. In normal cerebellum, MyoD was expressed in the proliferating granule neuron progenitors that are thought to be precursors to medulloblastoma. Similar to some other tumor suppressors that are induced in cancer, MyoD was expressed in proliferating medulloblastoma cells in three mouse models and in human medulloblastoma cases. This suggests that although expression of MyoD in a proliferating tumor is insufficient to prevent tumor progression, its expression in the cerebellum hinders medulloblastoma genesis. The goal of the gene expression analysis was to determine whether the canonical myogenic differentiation program was involved in increased tumorigenicity following loss of MyoD in the SHH-driven mouse models of medulloblastoma. We compared MyoD+/+; SmoA2 (n=3) with MyoD+/- ;SmoA2 mouse medulloblastoma tumors (n=2).
Project description:Single cell transposon insertion site profiles were generated from A375 xenograft tumors that had aquired BRAF inhibitor resistance in vivo as a consequence of Sleeping Beauty transposon mutagenesis.
Project description:Creating spontaneous yet genetically tractable human tumors from normal cells presents a fundamental challenge. Retroviruses and transposons have been separately used as somatic cell insertional mutagens to identify cancer drivers in model organisms. Here we combined these mutagenic elements to enable cancer gene discovery starting with normal human cells. Lentivirus was used to seed gain- and loss-of-function gene disruption elements which were further deployed by Sleeping Beauty transposons throughout the genome of human bone explant mesenchymal cells. De novo tumors rapidly generated in this context were high-grade sarcomas corresponding to the spectrum of myxofibrosarcoma and undifferentiated pleomorphic sarcoma, aggressive neoplasms with a predilection for older adults. Tumor insertion sites were genome-wide and enriched in regions of recurrent somatic copy number alteration found in multiple cancers, with a bias towards those of sarcomas. Novel driver genes which sustain somatic alterations in cancer patients were pinpointed. We identify the gene HDLBP, which codes for the RNA binding protein vigilin, as a candidate tumor suppressor deleted at 2q37.3 in greater than one in ten tumors across multiple tissues of origin. Hybrid viral-transposon systems will accelerate the functional annotation of cancer genomes by enabling insertional mutagenesis screens in higher eukaryotes that are not amenable to germline transgenesis. Lentivirus was used to seed gain- and loss-of-function gene disruption elements which were further deployed by Sleeping Beauty (SB) transposons throughout the genome of human bone explant mesenchymal cells. Genomic locations of LV (lentiviral backbone) and SB insertion sites were mapped by a pooled strategy utilizing linear amplification mediated PCR (LAM-PCR), followed by Illumina next generation sequencing of the product pool.
Project description:Exploiting the full potential of insertional mutagenesis screens with retroviruses and transposons requires methods for distinguishing clonal from subclonal insertion events within heterogeneous tumor cell populations. Current protocols, based on ligation mediated PCR, depend on endonuclease based fragmentation of genomic DNA, resulting in strong biases in amplification and sequencing due to a fixed product sizes of the amplicon. We have developed a method called shear-splink, which enables the semi-quantitative high-throughput sequence analysis of insertional mutations, enabling us to count the number of cells harboring a given integration, within a heterogeneous sample. The shear-splink method enriches for (sub)clonal integrations, thereby reducing the contribution of irrelevant passenger mutations normally hampering a reliable identification of common integration sites. Additionally, this improvement allows us to identify genetic interactions between affected genes, co-occurring mutations and to study acquired resistance mechanisms both in vivo and in vitro. Sequencing of retrovrial integration sites by LM-PCR. The associated manuscript describes a new method to quantitatively determine retrovrial integration sites using an improved ligation-mediated PCR approach and subsequent 454 pyrosequencing. [GSM562151 to GSM562159]: Sequence data from different mixtures of 2 different cell lines (called AE6 and BB12) which are processed without a restriction enzyme. These cell lines are derived from an MMTV induced mammary tumor, for which we amplify the MMTV integration sites using a ligation-mediated PCR setup. We mixed these 2 cell lines, both with a different integration spectrum, to determine whether our amplification and sequencing protocol is quantitative, meaning that the coverage per integration site is decreasing upon a further dilution of the sample. [GSM641935 to GSM641950]: Unique Sleeping beauty induced lymphoma specimens (spleen) obtained from a cohort of 16 wild-type mice with the 129P2/C57BL/6J mixed background. [GSM776576 to GSM776956]: The 379 submitted specimens are originating from 127 unique leukemia/lymphoma samples, processed using 3 different techniques in order to identify Sleeping Beauty integration sites. We compared restriction enzyme based LM-PCR (RE-splink) with shearing based LM-PCR (shear-splink) on 127 unique Sleeping Beauty (SB) induced leukemia's/lymphomas. All sequence data generated by the 454 sequencing platform are submitted to GEO, including the final output of our sequence analysis pipeline (in bed format; see Supplementary files linked below). Previous submissions contained similar sequence information (integration sites of viruses or transposons driving tumorigenesis) and are all part of the same manuscript.
Project description:DDX3X is an ATP-dependent RNA helicase. Missense mutations in DDX3X gene are known to occur in WNT, SHH subgroup medulloblastomas. The role of DDX3X in medulloblastoma biology was studied by downregulating its expression in a SHH subgroup Daoy medulloblastoma cell line. DDX3X knockdown resulted in considerable reduction in proliferation, clonogenic potential and anchorage-independent growth of the medulloblastoma cells. Transcriptome analysis was performed to delineate the molecular mechanism underlying reduction in the malignant potential of the medulloblastoma cells upon DDX3X knockdown. Exogenous expression of three DDX3X missense mutants in the DDX3X knockdown cells could restore the malignant potential of the medulloblastoma cells.
Project description:We explore cellular heterogeneity in 28 childhood medulloblastoma (MB) (1 WNT, 9 SHH, 7 GP3 and 11 GP4) using single-cell RNA sequencing (scRNA-seq), immunohistochemistry and deconvolution of bulk transcriptomic data. Neoplastic cells are broadly clustered according to subgroup, and within subgroups discrete sample clustering is associated with chromosomal copy number variance. Each subgroup contains subpopulations exhibiting mitotic , undifferentiated and neuronal differentiated transcript profiles , corroborating other recent medulloblastoma scRNA-seq studies and identifying new subpopulations. We identify a photoreceptor-differentiated subpopulation that is predominantly found in GP3 medulloblastoma, and in SHH, a subpopulation that constitutes differentiating nodules . Deconvolution of a large transcriptomic dataset shows that neoplastic subpopulations are associated with major and minor subgroup subdivisions, for example, photoreceptor subpopulation cells are more abundant in GP3-alpha. This scRNA-seq dataset also demonstrates medulloblastoma subgroup-specific differences in the tumor microenvironment and immune landscape, and reveals an SHH nodule -associated myeloid subpopulation. Additionally, we perform scRNA-seq on genetically engineered mouse (GEM) models of GP3 and SHH medulloblastoma. These models specifically matched the corresponding human subgroup-specific neoplastic subpopulations. We provide an interactive online resource that facilitates exploration of these MB single cell datasets. Collectively, our findings advance our understanding of the neoplastic and immune landscape of the main medulloblastoma subgroups in both humans and GEM models.