Project description:The recognition of tumor heterogeneity has highlighted the necessity of examining tumor samples through the lens of single-cell genomics. In glioblastoma (GBM), a highly heterogeneous tumor, single-cell analysis is critical to assist in assessing tumor composition and in the longitudinal analysis of response to therapies. However, single-cell genomic approaches face practical challenges for broad implementation, underscoring the importance of developing deconvolution methods that may assist in the interpretation of bulk profiles and can be deployed at scale. Bulk DNA methylation data, a stable and widely used diagnostic tool in gliomas and central nervous system tumors, provides a promising substrate for deconvolution. However, the limited availability of cell state-specific references in DNA methylation, coupled with low-coverage single-cell DNA methylation data, poses significant challenges. We present a hierarchical non-negative matrix factorization approach to deconvolute bulk DNA methylation profiles, initially resolving cell types and subsequently refining cell states within a cell type. By integrating multi-omics single-cell data, we mapped DNA methylation components to their transcriptional counterparts, enabling accurate predictions of transcriptional cellular composition from bulk DNA methylation. This methodology allows the decomposition of GBM bulk DNA methylation into glial, immune, neuronal, and malignant cell types, with further distinction into malignant stem-like and malignant differentiated cell states. Our findings reveal that low cancer cell fractions can distort classification, prompting the development of an in-silico purification method to enhance diagnostic accuracy. Additionally, we provide a framework to assist in quantifying the influences of the immune micro-environment on GBM bulk classification, unmasking the underlying genetic heterogeneity and tumor subtype. Our work provides a blueprint to reconcile DNA methylation, bulk transcription-based and single-cell classifications of GBM.
Project description:Analysis of gene expression in pathologically confirmed glioblastoma (GBM) samples. These data were used to test a classifier that was generated to distinguish GBM tumor samples with loss of neurofibromin 1 (NF1) function
Project description:we report that U251 glioblastoma tumor spheres exhibit low cytosolic folate cycle and a reprogrammmed mitochondrial folate cycle that is presumably oriented towards oxidizing the formyl group to CO2 with the production of TetraHydroFolate and release of NADPH instead of synthesizing formate
Project description:Glioblastoma is characterized by heterogeneous malignant cells that are functionally integrated within the neuroglial microenvironment. Here, we model this ecosystem by growing glioblastoma into long-term cultured human cortical organoids that contain the major neuroglial cell types found in the cerebral cortex. Single-cell RNA-seq analysis suggests that, compared to matched gliomasphere models, glioblastoma cortical organoids (GCO) more faithfully recapitulate the diversity and expression programs of malignant cell states found in patient tumors. Additionally, we observe widespread transfer of glioblastoma transcripts and GFP proteins to non-malignant cells in the organoids. Mechanistically, this transfer involves extracellular vesicles and is biased towards defined glioblastoma cell states and astroglia cell types. These results extend previous glioblastoma-organoid modeling efforts and suggest widespread intercellular transfer in the glioblastoma neuroglial microenvironment.
Project description:Understanding the cellular origin and differentiation status of glioblastoma is critical to resolve the etiology of the disease. we profile control and genetically modified human brain perivasuclar fibroblasts by single cell RNA sequencing (scRNAseq). From this, we observed the potential tumorigenicity of brian perivascular fibroblasts.