Project description:The 18 kDa translocator protein (TSPO) emerges as an important PET biomarker to assess the tumor microenvironment (TME) in glioblastoma. However, various cellular sources hamper interpretation and biological understanding of TSPO and other immune biomarkers in the TME. Thus, we established a novel method, combining immunomagnetic cell sorting after radiotracer injection (scRadiotracing) with 3D histology via light sheet microscopy and proteomics to dissect cellular allocation of TSPO enrichment in glioblastoma. Single tumor cells of implanted SB28 glioblastoma mice indicated 1.37-fold higher TSPO tracer uptake and 1.46-fold higher TSPO protein expression levels when compared to tumor associated microglia/macrophages (TAMs). Using proteomics, we compared the proteome of tumor associated microglia/macrophages (TAMs), Tumor tissue (TT) and control microglia from WT mice without glioblastoma. This analysis identified TAM specific targets for PET radioligand development with additional potential to monitor diverse TAM subpopulations in vivo. In summary, our data indicate that tumor cells need to be acknowledged as the main contributor to TSPO as a biomarker in glioblastoma. Combining cellular tracer uptake measures with 3D histology facilitates precise allocation of complex PET signal sources and will serve to validate novel TAM specific radioligands.
Project description:Glioblastoma is a lethal brain tumor which exhibits heterogeneity and resistance to therapy. Our understanding of tumor homeostasis is limited by a lack of genetic tools to selectively identify tumor states and fate transitions. Here, we use glioblastoma subtype signatures to construct synthetic genetic tracing cassettes and investigate tumor heterogeneity at cellular and molecular level, in vitro and in vivo. Through synthetic locus control regions, we demonstrated that proneural glioblastoma is a hardwired identity, whereas the mesenchymal glioblastoma is an adaptive and metastable cell state driven by pro-inflammatory and differentiation cues and DNA damage, but not hypoxia. Importantly, we discovered that innate immune cells divert glioblastoma cells to a proneural-to-mesenchymal transition which confers therapeutic resistance. Our synthetic genetic tracing methodology is simple, scalable and widely applicable to study homeostasis in development and diseases. In glioblastoma, the method causally links distinct (micro)environmental, genetic and pharmacological perturbations and mesenchymal commitment.
Project description:MicroRNAs (miRNAs) are non-coding molecules involved in post-transcriptional gene regulation that have been shown to modulate tumor cell proliferation and apoptosis and to act as oncogenes or tumor-suppressor genes. Although miRNAs have been linked to tumor progression, the connection between tumor-mediated immune modulation and miRNAs has yet to be explored. Specifically, how the miRNA dysregulation affects the monocyte-derived glioblastoma-infiltrating macrophages, the most abundant immune cell population within the glioblastoma microenvironment, and their immune suppressive properties has not been evaluated to date. Here we managed to purify the glioblastoma-infiltrating macrophages from the tumor microenvironment and compared their miRNA expression profile with the matched peripheral monocytes from the peripheral blood of the same GBM patient as well as with healthy donors. Of note, several most down-regulated miRNA candidates revealed in this study, including miR-142-3p, were also known for their role in mediating tumor-associated immunosuppression. These results suggest a novel approach to identify miRNA immune therapeutics using a two-step process: 1) screen miRNA expression from tumor-associated immune cells relative to normal immune cell, and 2) select and prioritize potential candidates on the basis of binding to immunosuppressive pathways or mechanisms. In the study presented here, 12 samples, including peripheral monocyte samples from 4 healthy donors, peripheral monocytes from 4 GBM patients and matched tumor-infiltrating macrophages extracted from the glioblastoma microenvironment, were used to acquire the miRNA expression profiles of 1732 unique mature miRNA sequences via the Phalanx Human miRNA OneArray Microarray v3 Platform.
Project description:Glioblastoma is an incurable brain cancer characterized by high genetic and pathological heterogeneity. Here we mapped active chromatin landscapes with gene expression, whole-exomes, copy number profiles, and DNA methylomes across 44 glioblastoma stem cell (GSCs) models, 50 primary glioblastomas, and 10 neural stem cells (NSCs) with the goal of identifying essential super enhancer (SE)-associated genes and the core transcription factors that establish them and glioblastoma identity. Glioblastomas segregate with two dominant enhancer profiles that coopt unique developmental transcription factor regulatory programs to enforce tumor identity. From group specific enhancer profiles, we inferred core transcription factors that define subgroup identity. These transcription factors show higher activity in glioblastomas versus normal neural stem cells, are associated with poor clinical outcomes, and are required for glioblastoma growth in vitro and in vivo. Given challenges with genetically-defined targeted therapies for glioblastoma, we propose targeting underlying transcriptional identity may serve as an important therapeutic strategy.
Project description:Glioblastoma is an incurable brain cancer characterized by high genetic and pathological heterogeneity. Here we mapped active chromatin landscapes with gene expression, whole-exomes, copy number profiles, and DNA methylomes across 44 glioblastoma stem cell (GSCs) models, 50 primary glioblastomas, and 10 neural stem cells (NSCs) with the goal of identifying essential super enhancer (SE)-associated genes and the core transcription factors that establish them and glioblastoma identity. Glioblastomas segregate with two dominant enhancer profiles that coopt unique developmental transcription factor regulatory programs to enforce tumor identity. From group specific enhancer profiles, we inferred core transcription factors that define subgroup identity. These transcription factors show higher activity in glioblastomas versus normal neural stem cells, are associated with poor clinical outcomes, and are required for glioblastoma growth in vitro and in vivo. Given challenges with genetically-defined targeted therapies for glioblastoma, we propose targeting underlying transcriptional identity may serve as an important therapeutic strategy.
Project description:Glioblastoma is an incurable brain cancer characterized by high genetic and pathological heterogeneity. Here we mapped active chromatin landscapes with gene expression, whole-exomes, copy number profiles, and DNA methylomes across 44 glioblastoma stem cell (GSCs) models, 50 primary glioblastomas, and 10 neural stem cells (NSCs) with the goal of identifying essential super enhancer (SE)-associated genes and the core transcription factors that establish them and glioblastoma identity. Glioblastomas segregate with two dominant enhancer profiles that coopt unique developmental transcription factor regulatory programs to enforce tumor identity. From group specific enhancer profiles, we inferred core transcription factors that define subgroup identity. These transcription factors show higher activity in glioblastomas versus normal neural stem cells, are associated with poor clinical outcomes, and are required for glioblastoma growth in vitro and in vivo. Given challenges with genetically-defined targeted therapies for glioblastoma, we propose targeting underlying transcriptional identity may serve as an important therapeutic strategy.
Project description:Glioblastoma multiforme (GBM), the most common and aggressive primary brain tumor in adults, can be divided into several molecular subtypes including proneural GBM. Most clinical strategies aimed at directly targeting glioma cells in these tumors have failed. A promising alternative is to target stromal cells in the brain microenvironment, such as tumor-associated microglia and macrophages (TAMs). Macrophages are dependent upon colony stimulating factor (CSF)-1 for differentiation and survival; therefore, we used an inhibitor of its receptor, CSF-1R, to target macrophages in a mouse proneural GBM model. CSF-1R inhibition dramatically increased survival in mice and regressed established GBMs. Tumor cell apoptosis was significantly increased, and proliferation and tumor grade markedly decreased. Surprisingly, TAMs were not depleted in tumors treated with the CSF-1R inhibitor. Instead, analysis of gene expression in TAMs isolated from treated tumors revealed a decrease in alternatively activated/ M2 macrophage markers, consistent with impaired tumor-promoting functions. These gene signatures were also associated with better survival specifically in the proneural subtype of patient gliomas. Collectively, these results establish macrophages as valid therapeutic targets in proneural gliomas, and highlight the clinical potential for CSF-1R inhibitors in GBM. RNA was isolated from sorted tumor associated macrophages (TAMs) from murine gliomas following either 7 days of vehicle or BLZ945 treatment. Samples were collected from 16 total tumor burdened mice, with 8 replicates for each treatment group. BLZ945: a Colony-Stimulating Factor 1 Receptor (CSF-1R) inhibitor
Project description:Brain tumors are dynamic complex ecosystems with multiple cell types. To model the brain tumor microenvironment in a reproducible and scalable system, we developed a rapid three-dimensional (3D) bioprinting method to construct clinically relevant biomimetic tissue models. In recurrent glioblastoma, macrophages/microglia prominently contribute to the tumor mass. To parse the function of macrophages in 3D, we compared the growth of glioblastoma stem cells (GSCs) alone or with astrocytes and neural precursor cells (NPCs) in a hyaluronic acid (HA)-rich hydrogel, with or without macrophages. Bioprinted constructs integrating macrophage recapitulate patient-derived transcriptional profiles predictive of patient survival, maintenance of stemness, invasion, and drug resistance. Whole genome CRISPR screening with bioprinted complex systems identified unique molecular dependencies in GSCs, relative to sphere culture. Multicellular bioprinted models serve as a scalable and physiologic platform to interrogate drug sensitivity, cellular crosstalk, invasion, context-dependent functional dependencies, as well as immunologic interactions in a species-matched neural environment.
Project description:To identify markers associated with inherent cellular sex-identity, we analysed macrophages from newly-hatched chicks. We found that male and female macrophages respond differently to stimulation by bacterial lipopolysaccharide and that female macrophages constitutively express higher levels of interferon target genes than male macrophages. Macrophages were collected from leg-bones of chickens between 1 and 3 days after hatch. Three pools of macrophage cells were made for male and female cultures. Cells were cultured in either standard medium or in medium containing lipopolysaccharide (LPS) to activate the macrophages. Macrophages were harvested and RNA collected for microarray analysis.