Multiregional sampling of primary glioblastoma specimens
Ontology highlight
ABSTRACT: Glioblastoma (GBM), the most common malignant tumor originating in the brain remains incurable with few treatment advances despite decades of investigation. Treatment failure is often attributed to intratumoral heterogeneity, which fosters tumor evolution and selection of resistant clones. However, intratumoral heterogeneity and tumor evolution remain poorly understood in GBM as studies are typically based on single tissue biopsies and lack spatial context. Here, we have utilized pre-operative MRI scans and intra-operative 3-D surgical neuronavigation for 10 primary IDH-WT GBM patients to acquire 103 tissue samples that represent maximal tumor diversity and are mapped by 3-D spatial coordinates. We combine insights from deconvolution of GBM transcriptomes and chromatin landscapes with single-cell analysis to assess intratumoral heterogeneity of each program at the cellular level and to distinguish neuronal, glial, and immune programs aberrantly active in tumor cells from their counterparts in normal cells. Collectively, these data provide unprecedented insight into GBM intratumoral heterogeneity and evolution from single-cell to whole-tumor 3D spatial resolution, redefining current understanding and providing a rich resource of targets for therapeutic investigation.
Project description:Glioblastoma (GBM), the most common primary brain cancer in adults, remains incurable with no targeted therapies approved despite decades of investigation into its molecular landscape. Treatment failure is attributed to intratumoral heterogeneity in the GBM genome and epigenome, which foster tumor evolution and selection of resistant clones. However, tumor evolution and intratumoral heterogeneity remain poorly understood on the level of the whole tumor as most studies are based on single samples per patient and lack spatial context. Here, we have used 3-D neuronavigation during surgical resection for 10 primary IDH-WT GBM patients to collect 102 samples representing maximal tumor diversity, each mapped by 3-D spatial coordinates. We have applied a strategic set of genomic and epigenomic assays spanning multiple levels of resolution to discover, orthogonally validate, and functionally assess drivers of tumor evolution and intratumoral heterogeneity. These include extrachromosomal DNA amplifications, chromothripsis events, inversions, and translocations that disrupt both the GBM genome and epigenome while generating fusion transcripts and opportunities for therapeutic intervention. We define epigenomic programs that contribute to GBM evolution and intratumoral heterogeneity, revealing their 3-D spatial patterning within whole tumors and their cell type(s) of origin in single-cell data from the same tumor samples. Notably, we distinguish neuronal, glial, and immune programs aberrantly active in tumor cells from their counterparts in normal cells and discover NEUROD1, JUN/FOS, and NF1 transcription factors as key drivers of GBM evolution and growth. Collectively, these data provide unprecedented insight into GBM evolution and intratumoral heterogeneity from single-cell to whole-tumor resolution, redefining current understanding and providing a rich resource of targets for therapeutic investigation.
Project description:Intratumor spatial heterogeneity facilitates therapeutic resistance in glioblastoma (GBM). Nonetheless, understanding of GBM is limited to the resectable tumor core lesion while the seeds for recurrence reside in the unresectable tumor edge. In this study, stratification of GBM to core and edge demonstrated clinically relevant surgical sequelae. We establish regionally derived models of GBM edge and core that retain their spatial identity in a cell autonomous manner. Edge cells show a higher capacity for infiltrative growth, while core cells demonstrate greater therapy resistance. Investigation of intercellular signaling between these two cell populations uncovered the paracrine crosstalk from tumor core that provokes malignancy and therapy resistance of edge cells. These phenotypic alterations were initiated by HDAC1 in GBM core cells which subsequently affect edge cells by secreting the soluble form of CD109 protein. Our data reveal the role of intracellular communication between regionally different populations of GBM cells in tumor recurrence.
Project description:Glioblastoma (GBM) is characterized by an exceptionally high intratumoral heterogeneity. However, the molecular mechanisms underlying the origin of different GBM cell populations remain unclear. Here we found that the composition of ribosomes of GBM cells in the tumor core and edge differ due to alternative RNA splicing. The acidic pH in the core switches pre-mRNA splicing of the ribosomal gene RPL22L1 toward the RPL22L1b isoform. To elucidate the functions of RPL22L1 isoforms we identified proteins that interact with RPL22L1a and RPL22L1b. First, we generated GBM cells with stable expression of Fc-tagged RPL22L1 isoforms. Fc-RPL22L1a and Fc-RPL22L1b together with their binding partners were isolated from neurospheres using magnetic beads and analyzed by LC-MS/MS.
Project description:Glioblastoma (GBM) is characterized by an exceptionally high intratumoral heterogeneity. However, the molecular mechanisms underlying the origin of different GBM cell populations remain unclear. Here we found that the composition of ribosomes of GBM cells in the tumor core and edge differ due to alternative RNA splicing. The acidic pH in the core switches pre-mRNA splicing of the ribosomal gene RPL22L1 toward the RPL22L1b isoform. To elucidate the functions of RPL22L1 isoforms we identified proteins that interact with RPL22L1a and RPL22L1b. First, each isoform was expressed in E. coli and immobilized on magnetic beads. The beads were incubated with GBM cell lysates and proteins bound to the beads were identified using LC-MS/MS.
Project description:Glioblastoma undergoes a complex and dynamic evolution involving genetic and epigenetic changes. Understanding the mechanisms behind this evolution is vital for effective therapies. While treatment resistance is associated with glioblastoma's intratumoral heterogeneity, it remains uncertain if hypometabolic and hypermetabolic lesions observed through PET imaging are influenced by spatial intratumoral genomic evolution. In this study, we precisely isolated autologous hypometabolic and hypermetabolic lesions from glioblastoma using advanced neurosurgical and brain imaging technologies, followed by comprehensive whole-genome/exome and transcriptome analysis. Our findings reveal that hypermetabolic lesions evolve from hypometabolic lesions, harbor shrewd focal amplifications and deletions, and exhibit a higher frequency of critical genomic alterations linked to increased aggressiveness. We also found gene signatures in hypermetabolic lesions, including upregulated APOBEC3, hypoxic genes, and downregulated putative tumor suppressors. This study highlights a spatial genomic evolution with diagnostic implications and unveils obstacles and possibilities that should be considered in the development of novel therapeutic strategies.
Project description:Glioblastoma cells infiltrate and incorporate into the normal brain parenchyma. We conduct unbiased multimodal single-cell and spatial sequencing to capture GBM cells and the surrounding tumor microenvironment using a regional sampling strategy. For each patient, we profile the peritumoral region, tumor edge, and tumor core, providing a comprehensive characterization of the transcriptional and epigenetic landscape of GBM spatial heterogeneity, with a specific focus on infiltrative cells.
Project description:Glioblastoma cells infiltrate and incorporate into the normal brain parenchyma. We conduct unbiased multimodal single-cell and spatial sequencing to capture GBM cells and the surrounding tumor microenvironment using a regional sampling strategy. For each patient, we profile the peritumoral region, tumor edge, and tumor core, providing a comprehensive characterization of the transcriptional and epigenetic landscape of GBM spatial heterogeneity, with a specific focus on infiltrative cells.
Project description:Glioblastoma cells infiltrate and incorporate into the normal brain parenchyma. We conduct unbiased multimodal single-cell and spatial sequencing to capture GBM cells and the surrounding tumor microenvironment using a regional sampling strategy. For each patient, we profile the peritumoral region, tumor edge, and tumor core, providing a comprehensive characterization of the transcriptional and epigenetic landscape of GBM spatial heterogeneity, with a specific focus on infiltrative cells.
Project description:Glioblastoma cells infiltrate and incorporate into the normal brain parenchyma. We conduct unbiased multimodal single-cell and spatial sequencing to capture GBM cells and the surrounding tumor microenvironment using a regional sampling strategy. For each patient, we profile the peritumoral region, tumor edge, and tumor core, providing a comprehensive characterization of the transcriptional and epigenetic landscape of GBM spatial heterogeneity, with a specific focus on infiltrative cells.
Project description:High-grade gliomas are aggressive primary brain cancers with poor response to standard regimens, driven by immense heterogeneity. In isocitrate dehydrogenase (IDH) wild-type high-grade glioma (glioblastoma, GBM), increased intra-tumoral heterogeneity is associated with more aggressive disease. Recently, spatial technologies have emerged to dissect this complex heterogeneity within the tumor ecosystem by preserving cellular organization in situ. Here, we construct a high- resolution molecular landscape of GBM and IDH-mutant high-grade glioma patient samples to investigate the cellular subtypes and spatial communities that compose high-grade glioma using digital spatial profiling and spatial molecular imaging. This uncovered striking diversity of the tumor and immune microenvironment, that is embodied by the heterogeneity of the inferred copy- number alterations in the tumor. Reconstructing the tumor architecture revealed brain-intrinsic niches, composed of tumor cells reflecting brain cell types and microglia; and brain-extrinsic niches, populated by mesenchymal tumor cells and monocytes. We further reveal that cellular communication in these niches is underpinned by specific ligand-receptor pairs. This primary study reveals high levels of intra-tumoral heterogeneity in high-grade gliomas, associated with a diverse immune landscape within spatially localized regions.