Like all cancers, brain tumors require a continuous source of energy and molecular resources for new cell production. In normal brain, glucose is an essential neuronal fuel, but the blood-brain barrier limits its delivery. We now report that nutrient restriction contributes to tumor progression by enriching for brain tumor initiating cells (BTICs) due to preferential BTIC survival and adaptation of non-BTICs through acquisition of BTIC features. BTICs outcompete for glucose uptake by co-opting the high affinity neuronal glucose transporter, type 3 (Glut3, SLC2A3). BTICs preferentially express Glut3 and targeting Glut3 inhibits BTIC growth and tumorigenic potential. Glut3, but not Glut1, correlates with poor survival in brain tumors and other cancers; thus, TICs may extract nutrients with high affinity. As altered metabolism represents a cancer hallmark, metabolic reprogramming may instruct the tumor hierarchy and portend poor prognosis.

Significant endeavor has been applied to identify functional therapeutic targets in glioblastoma (GBM) to halt the growth of this aggressive cancer. We show that the receptor tyrosine kinase EphA3 is frequently overexpressed in GBM and, in particular, in the most aggressive mesenchymal subtype. Importantly, EphA3 is highly expressed on the tumor-initiating cell population in glioma and appears critically involved in maintaining tumor cells in a less differentiated state by modulating mitogen-activated protein kinase signaling. EphA3 knockdown or depletion of EphA3-positive tumor cells reduced tumorigenic potential to a degree comparable to treatment with a therapeutic radiolabelled EphA3-specific monoclonal antibody. These results identify EphA3 as a functional, targetable receptor in GBM.

Background:The sphingolipid metabolite sphingosine 1-phosphate (S1P) is a potent angiogenic factor. Results: S1P content is 9-fold higher in glioblastomas compared with normal brain, and S1P production is necessary for glioblastoma cells to trigger endothelial cell angiogenesis. Conclusion: Excessive S1P synthesis is a major contributor to glioblastoma angiogenesis. Significance: Inhibiting S1P synthesis may be a valuable antiangiogenic approach in glioblastoma.

Low-passage, serum-free cell lines cultured from patient tumour tissue are the gold-standard for preclinical studies and cellular investigations of glioblastoma (GBM) biology, yet entrenched, poorly-representative cell line models are still widely used, compromising the significance of much GBM research. We submit that greater adoption of these critical resources will be promoted by the provision of a suitably-sized, meaningfully-described reference collection along with appropriate tools for working with them. Consequently, we present a curated panel of 12 readily-usable, genetically-diverse, tumourigenic, patient-derived, low-passage, serum-free cell lines representing the spectrum of molecular subtypes of IDH-wildtype GBM along with their detailed phenotypic characterisation plus a bespoke set of lentiviral plasmids for bioluminescent/fluorescent labelling, gene expression and CRISPR/Cas9-mediated gene inactivation. The cell lines and all accompanying data are readily-accessible via a single website, Q-Cell (qimrberghofer.edu.au/q-cell/) and all plasmids are available from Addgene. These resources should prove valuable to investigators seeking readily-usable, well-characterised, clinically-relevant, gold-standard models of GBM.

Gliomas are the most common tumours of the central nervous system and the most aggressive form is glioblastoma (GBM). Despite advances in treatment, patient survival remains low. GBM diagnosis typically relies on imaging techniques and postoperative pathological diagnosis; however, both procedures have their inherent limitations. Imaging modalities cannot differentiate tumour progression from treatment-related changes that mimic progression, known as pseudoprogression, which might lead to misinterpretation of therapy response and delay clinical interventions. In addition to imaging limitations, tissue biopsies are invasive and most of the time cannot be performed over the course of treatment to evaluate 'real-time' tumour dynamics. In an attempt to address these limitations, liquid biopsies have been proposed in the field. Blood sampling is a minimally invasive procedure for a patient to endure and could provide tumoural information to guide therapy. Tumours shed tumoural content, such as circulating tumour cells, cell-free nucleic acids, proteins and extracellular vesicles, into the circulation, and these biomarkers are reported to cross the blood-brain barrier. The use of liquid biopsies is emerging in the field of GBM. In this review, we aim to summarise the current literature on circulating biomarkers, namely circulating tumour cells, circulating tumour DNA and extracellular vesicles as potential non-invasively sampled biomarkers to manage the treatment of patients with GBM.

Breast cancer risk is strongly associated with an intergenic region on 11q13. We have previously shown that the strongest risk-associated SNPs fall within a distal enhancer that regulates CCND1. Here, we report that, in addition to regulating CCND1, this enhancer regulates two estrogen-regulated long noncoding RNAs, CUPID1 and CUPID2. We provide evidence that the risk-associated SNPs are associated with reduced chromatin looping between the enhancer and the CUPID1 and CUPID2 bidirectional promoter. We further show that CUPID1 and CUPID2 are predominantly expressed in hormone-receptor-positive breast tumors and play a role in modulating pathway choice for the repair of double-strand breaks. These data reveal a mechanism for the involvement of this region in breast cancer.

The ability of cancer cells to sense external mechanical forces has emerged as a significant factor in the promotion of cancer invasion. Currently there are conflicting reports in the literature with regard to whether glioblastoma (GBM) brain cancer cell migration and invasion is rigidity-sensitive. In order to address this question we have compared the rigidity-response of primary patient-derived GBM lines. Cells were plated on polyacrylamide gels of defined rigidity that reflect the diversity of the brain tissue mechanical environment, and cell morphology and migration were analysed by time-lapse microscopy. Invasiveness was assessed in multicellular spheroids embedded in 3D matrigel cultures. Our data reveal a range of rigidity-dependent responses between the patient-derived cell lines, from reduced migration on the most compliant tissue stiffness to those that are insensitive to substrate rigidity and are equally migratory irrespective of the underlying substrate stiffness. Notably, the rigidity-insensitive GBM cells show the greatest invasive capacity in soft 3D matrigel cultures. Collectively our data confirm both rigidity-dependent and independent behaviour in primary GBM patient-derived cells.

The role of astrocytes is becoming increasingly important to understanding how glioblastoma (GBM) tumor cells diffusely invade the brain. Yet, little is known of the contribution of extracellular vesicle (EV) signaling in GBM/astrocyte interactions. We modeled GBM-EV signaling to normal astrocytes in vitro to assess whether this mode of intercellular communication could support GBM progression. EVs were isolated and characterized from three patient-derived GBM stem cells (NES + /CD133 + ) and their differentiated ( diff ) progeny cells (NES − /CD133 − ). Uptake of GBM-EVs by normal primary astrocytes was confirmed by fluorescence microscopy, and changes in astrocyte podosome formation and gelatin degradation were measured. Quantitative mass spectrometry-based proteomics was performed on GBM-EV stimulated astrocytes. Interaction networks were generated from common, differentially abundant proteins using Ingenuity® (Qiagen Bioinformatics) and predicted upstream regulators were tested by qPCR assays. Podosome formation and Cy3-gelatin degradation were induced in astrocytes following 24-h exposure to GBM- stem and - diff EVs, with EVs released by GBM- stem cells eliciting a greater effect. More than 1700 proteins were quantified, and bioinformatics predicted activations of MYC, NFE2L2, FN1, and TGFβ1 and inhibition of TP53 in GBM-EV stimulated astrocytes that were then confirmed by qPCR. Further qPCR studies identified significantly decreased Δ133p53 and increased p53 β in astrocytes exposed to GBM-EVs that might indicate the acquisition of a pro-inflammatory, tumor-promoting senescence-associated secretory phenotype (SASP). Inhibition of TP53 and activation of MYC signaling pathways in normal astrocytes exposed to GBM-EVs may be a mechanism by which GBM manipulates astrocytes to acquire a phenotype that promotes tumor progression. Electronic supplementary material The online version of this article (10.1007/s12035-018-1385-1) contains supplementary material, which is available to authorized users.