Project description:<p>The UCSF Adult Glioma Study is a case-control study conducted at the University of California, San Francisco. The goals of the study were to discover inherited (genetic), developmental, immunologic and other risk factors for glioma and to determine molecular level tumor markers that would be helpful in classifying glioma into more homogeneous groups.</p>
Project description:Developing a classification model based on differential expression miRNAs profile in serum WHO CNS5 adult-type diffuse glioma samples to improve of diagnosis of grade 4 glioma.
Project description:Glioblastoma, the most common and malignant brain tumor, harbors stem-like cells that self-renew and propagate upon serial transplantation. Although they share functional, morphological and developmental similarities to adult brain neural stem cells, stem cell characteristic pathways contributing to glioblastoma stem-like cells have not been consistently determined. Towards this goal we have provided an internally coherent molecular reference that compares adult neural and glioblastoma stem cells cultivated under identical conditions. Genes dysregulated between these populations are correlated with clinical outcome in glioblastoma, and are highly expressed in embryonic and induced pluripotent stem cells. The resource yields a key role for Wnt and a core group of dysregulated pathways. We have verified the contribution to proliferation and sphere formation of Wnt- differentially activated genes through the Wnt inhibitor SFRP1. The glioblastoma and neural stem cell gene-expression and pathway comparative resource provides a powerful new tool for the identification of potential therapeutic targets. 14 samples was analyzed; 5 individual samples of adult neural stem cells and 9 individual samples of glioma stem cells
Project description:Primary glioblastoma, representing over 90% of adult glioblastoma, develop rapidly without preexisting lower-grade glioma. We have generated a mouse model of primary glioblastoma driven by a single p53 mutation. These p53-mutant gliomas lose the syntenic region of human chromosome 10q, which is mapped to mouse chr19 and chr7. Loss of mouse chr19, containing Pten, activates PI3K/Akt signaling. Rictor/mTORC2 deletion inhibits Akt signaling, causing a significant delay in p53-mutant driven glioma formation. Unexpectedly, Rictor/mTORC2 loss promotes p53-mutant driven medulloblastomas with unique features of pediatric SHH medulloblastoma. Mechanistically, Rictor/mTORC2 loss inhibits the generation of glioma precursor cells from neural stem/progenitor cells in the adult brain, while causing a delay in differentiation of granule cell precursors in the developing brain, a cell-of-origin of SHH medulloblastoma.
Project description:In human, the 39 coding HOX genes and 18 referenced non-coding antisense transcripts are arranged in four genomic clusters named HOXA, B, C, and D. This highly conserved family belongs to the homeobox class of genes that encode transcription factors required for normal development. Therefore, HOX gene deregulation might contribute to the development of many cancer types. Here, we study HOX gene deregulation in adult glioma, a common type of primary brain tumor. We performed extensive molecular analysis of tumor samples, classified according to their isocitrate dehydrogenase (IDH1) gene mutation status, and of glioma stem cells. We found widespread expression of sense and antisense HOX transcripts only in aggressive (IDHwt) glioma samples, although the four HOX clusters displayed DNA hypermethylation. Integrative analysis of expression-, DNA methylation- and histone modification signatures along the clusters revealed that HOX gene upregulation relies on canonical and alternative bivalent CpG island promoters that escape hypermethylation. H3K27me3 loss at these promoters emerges as the main cause of widespread HOX gene upregulation in IDHwt glioma cell lines and tumors. Our study provides the first comprehensive description of the epigenetic changes at HOX clusters and their contribution to the transcriptional changes observed in adult glioma. It also identified putative "master" HOX proteins that might contribute to the tumorigenic potential of glioma stem cells.
Project description:How malignant gliomas arise in a mature brain remains a mystery, hindering the development of preventive and therapeutic interventions. We previously showed that oligodendrocyte precursor cells (OPCs) can be transformed into glioma when mutations are introduced perinatally. However, adult OPCs rarely proliferate compared to their perinatal counterparts. Whether these relatively quiescent cells have the potential to transform is unknown, which is a critical question considering the late onset of human glioma. Additionally, the events taking place between initial mutation and a fully developed tumor mass (pre-malignant phase) are particularly poorly understood in glioma. Here we used a temporally controllable Cre transgene to delete p53 and NF1 specifically in adult OPCs, and demonstrated that these cells consistently give rise to malignant gliomas. To investigate the transforming process of quiescent adult OPCs, we then tracked these cells throughout the pre-malignant phase, which revealed a dynamic multi-step transformation, starting with rapid but transient hyper-proliferative reactivation, followed by a long period of dormancy, then final malignant transformation. Using pharmacological approaches, we discovered that mTOR signaling is critical for both the initial OPC reactivation step and late stage tumor cell proliferation, and thus might be a potential target for both glioma prevention and treatment. In summary, our results firmly establish the transforming potential of adult OPCs, and reveal an actionable multi-phasic reactivation process that turns slowly dividing OPCs into malignant gliomas.