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23 result(s) for "Jeffree, Rosalind L."
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A reference collection of patient-derived cell line and xenograft models of proneural, classical and mesenchymal 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.
A pilot study: Metabolic profiling of plasma and saliva samples from newly diagnosed glioblastoma patients
Background Despite aggressive treatment, more than 90% of glioblastoma (GBM) patients experience recurrences. GBM response to therapy is currently assessed by imaging techniques and tissue biopsy. However, difficulties with these methods may cause misinterpretation of treatment outcomes. Currently, no validated therapy response biomarkers are available for monitoring GBM progression. Metabolomics holds potential as a complementary tool to improve the interpretation of therapy responses to help in clinical interventions for GBM patients. Methods Saliva and blood from GBM patients were collected pre and postoperatively. Patients were stratified conforming their progression‐free survival (PFS) into favourable or unfavourable clinical outcomes (>9 months or PFS ≤ 9 months, respectively). Analysis of saliva (whole‐mouth and oral rinse) and plasma samples was conducted utilising LC‐QqQ‐MS and LC‐QTOF‐MS to determine the metabolomic and lipidomic profiles. The data were investigated using univariate and multivariate statistical analyses and graphical LASSO‐based graphic network analyses. Results Altogether, 151 metabolites and 197 lipids were detected within all saliva and plasma samples. Among the patients with unfavourable outcomes, metabolites such as cyclic‐AMP, 3‐hydroxy‐kynurenine, dihydroorotate, UDP and cis‐aconitate were elevated, compared to patients with favourable outcomes during pre‐and post‐surgery. These metabolites showed to impact the pentose phosphate and Warburg effect pathways. The lipid profile of patients who experienced unfavourable outcomes revealed a higher heterogeneity in the abundance of lipids and fewer associations between markers in contrast to the favourable outcome group. Conclusion Our findings indicate that changes in salivary and plasma metabolites in GBM patients can potentially be employed as less invasive prognostic biomarkers/biomarker panel but validation with larger cohorts is required. Saliva and plasma samples were collected from 21 newly diagnosed GBM patients pre and post‐operatively. Metabolomic and lipidomic profiles were analysed using LC‐QqQ‐MS and LC‐QTOF‐MS. GBM patients were classified as favourable or unfavourable patients according to clinical outcomes (progression‐free survival (PFS) >nine months or PFS ≤nine months, respectively). The data were investigated using univariate and multivariate statistical analyses and graphical LASSO‐based graphic network analyses.
Innovative Therapeutic Strategies for Effective Treatment of Brain Metastases
Brain metastases are the most prevalent of intracranial malignancies. They are associated with a very poor prognosis and near 100% mortality. This has been the case for decades, largely because we lack effective therapeutics to augment surgery and radiotherapy. Notwithstanding improvements in the precision and efficacy of these life-prolonging treatments, with no reliable options for adjunct systemic therapy, brain recurrences are virtually inevitable. The factors limiting intracranial efficacy of existing agents are both physiological and molecular in nature. For example, heterogeneous permeability, abnormal perfusion and high interstitial pressure oppose the conventional convective delivery of circulating drugs, thus new delivery strategies are needed to achieve uniform drug uptake at therapeutic concentrations. Brain metastases are also highly adapted to their microenvironment, with complex cross-talk between the tumor, the stroma and the neural compartments driving speciation and drug resistance. New strategies must account for resistance mechanisms that are frequently engaged in this milieu, such as HER3 and other receptor tyrosine kinases that become induced and activated in the brain microenvironment. Here, we discuss molecular and physiological factors that contribute to the recalcitrance of these tumors, and review emerging therapeutic strategies, including agents targeting the PI3K axis, immunotherapies, nanomedicines and MRI-guided focused ultrasound for externally controlling drug delivery.
Current management of cerebral gliomas
Background: Despite their rarity, primary tumours of the central nervous system have a devastating impact on patient survival and quality of life. The classification of glial tumours has recently changed, and large trials have provided data on treatment impact; however, the treatment armamentarium remains the same, and many questions persist. Objective: The aim of this narrative review is to discuss the current understanding and management of the most common glial brain tumours to equip general practitioners (GPs) and other nonneuro- oncological specialists with appropriate knowledge to share care and support patients. Discussion: Treatment of brain tumours is complex and multifaceted, and it involves many different specialists. Recent advances in translational research and molecular understanding of brain tumours raise hope that new treatments are imminent, and patients should be encouraged to participate in clinical trials. The GP has an important role in patient support and coordination of care.
The dystroglycan receptor maintains glioma stem cells in the vascular niche
Glioblastomas (GBMs) are malignant central nervous system (CNS) neoplasms with a very poor prognosis. They display cellular hierarchies containing self-renewing tumourigenic glioma stem cells (GSCs) in a complex heterogeneous microenvironment. One proposed GSC niche is the extracellular matrix (ECM)-rich perivascular bed of the tumour. Here, we report that the ECM binding dystroglycan (DG) receptor is expressed and functionally glycosylated on GSCs residing in the perivascular niche. Glycosylated αDG is highly expressed and functional on the most aggressive mesenchymal-like (MES-like) GBM tumour compartment. Furthermore, we found that DG acts to maintain an MES-like state via tight control of MAPK activation. Antibody-based blockade of αDG induces robust ERK-mediated differentiation leading to reduced GSC potential. DG was shown to be required for tumour initiation in MES-like GBM, with constitutive loss significantly delaying or preventing tumourigenic potential in-vivo. These findings reveal a central role of the DG receptor, not only as a structural element, but also as a critical factor promoting MES-like GBM and the maintenance of GSCs residing in the perivascular niche.
PRECISION-TBI: a study protocol for a vanguard prospective cohort study to enhance understanding and management of moderate to severe traumatic brain injury in Australia
IntroductionTraumatic brain injury (TBI) is a heterogeneous condition in terms of pathophysiology and clinical course. Outcomes from moderate to severe TBI (msTBI) remain poor despite concerted research efforts. The heterogeneity of clinical management represents a barrier to progress in this area. PRECISION-TBI is a prospective, observational, cohort study that will establish a clinical research network across major neurotrauma centres in Australia. This network will enable the ongoing collection of injury and clinical management data from patients with msTBI, to quantify variations in processes of care between sites. It will also pilot high-frequency data collection and analysis techniques, novel clinical interventions, and comparative effectiveness methodology.Methods and analysisPRECISION-TBI will initially enrol 300 patients with msTBI with Glasgow Coma Scale (GCS) <13 requiring intensive care unit (ICU) admission for invasive neuromonitoring from 10 Australian neurotrauma centres. Demographic data and process of care data (eg, prehospital, emergency and surgical intervention variables) will be collected. Clinical data will include prehospital and emergency department vital signs, and ICU physiological variables in the form of high frequency neuromonitoring data. ICU treatment data will also be collected for specific aspects of msTBI care. Six-month extended Glasgow Outcome Scores (GOSE) will be collected as the key outcome. Statistical analysis will focus on measures of between and within-site variation. Reports documenting performance on selected key quality indicators will be provided to participating sites.Ethics and disseminationEthics approval has been obtained from The Alfred Human Research Ethics Committee (Alfred Health, Melbourne, Australia). All eligible participants will be included in the study under a waiver of consent (hospital data collection) and opt-out (6 months follow-up). Brochures explaining the rationale of the study will be provided to all participants and/or an appropriate medical treatment decision-maker, who can act on the patient’s behalf if they lack capacity. Study findings will be disseminated by peer-review publications.Trial registration numberNCT05855252.
Impaired signaling for neuromuscular synaptic maintenance is a feature of Motor Neuron Disease
A central event in the pathogenesis of motor neuron disease (MND) is the loss of neuromuscular junctions (NMJs), yet the mechanisms that lead to this event in MND remain to be fully elucidated. Maintenance of the NMJ relies upon neural agrin ( n -agrin) which, when released from the nerve terminal, activates the postsynaptic Muscle Specific Kinase (MuSK) signaling complex to stabilize clusters of acetylcholine receptors. Here, we report that muscle from MND patients has an increased proportion of slow fibers and muscle fibers with smaller diameter. Muscle cells cultured from MND biopsies failed to form large clusters of acetylcholine receptors in response to either non-MND human motor axons or n -agrin. Furthermore, levels of expression of MuSK, and MuSK-complex components: LRP4, Caveolin-3, and Dok7 differed between muscle cells cultured from MND patients compared to those from non-MND controls. To our knowledge, this is the first time a fault in the n -agrin-LRP4-MuSK signaling pathway has been identified in muscle from MND patients. Our results highlight the n -agrin-LRP4-MuSK signaling pathway as a potential therapeutic target to prolong muscle function in MND.
Q-Cell Glioblastoma Resource: Proteomics Analysis Reveals Unique Cell-States Are Maintained in 3D Culture
Glioblastoma (GBM) is a treatment-refractory central nervous system (CNS) tumour, and better therapies to treat this aggressive disease are urgently needed. Primary GBM models that represent the true disease state are essential to better understand disease biology and for accurate preclinical therapy assessment. We have previously presented a comprehensive transcriptome characterisation of a panel (n = 12) of primary GBM models (Q-Cell). We have now generated a systematic, quantitative, and deep proteome abundance atlas of the Q-Cell models grown in 3D culture, representing 6167 human proteins. A recent study has highlighted the degree of functional heterogeneity that coexists within individual GBM tumours, describing four cellular states (MES-like, NPC-like, OPC-like and AC-like). We performed comparative proteomic analysis, confirming a good representation of each of the four cell-states across the 13 models examined. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis identified upregulation of a number of GBM-associated cancer pathway proteins. Bioinformatics analysis, using the OncoKB database, identified a number of functional actionable targets that were either uniquely or ubiquitously expressed across the panel. This study provides an in-depth proteomic analysis of the GBM Q-Cell resource, which should prove a valuable functional dataset for future biological and preclinical investigations.
Population Pharmacokinetics of Levetiracetam in Patients with Traumatic Brain Injury and Subarachnoid Hemorrhage Exhibiting Augmented Renal Clearance
Background and Objective Patients with severe trauma exhibit augmented renal clearance, which can alter the dosing requirement of renally eliminated drugs. This study aimed to develop a population pharmacokinetic model for levetiracetam in patients with severe traumatic brain injury and aneurysmal subarachnoid hemorrhage, and use it to describe optimal dosing regimens. Methods This was a prospective open-label observational study. Critically ill adult patients with severe traumatic brain injury or aneurysmal subarachnoid hemorrhage without renal dysfunction and receiving levetiracetam were eligible. Serial levetiracetam plasma concentrations were analyzed to develop a population pharmacokinetic model and perform dosing simulations. Results A two-compartment model best described the concentration–time data from 30 patients. The mean ± standard deviation parameter estimates were bioavailability ( F ) of 0.8 ± 0.2, absorption rate constant of 2.4 ± 2 h −1 , clearance 2.5 ± 1.1 L/h, central volume of distribution 8.9 ± 3.0 L/h, and transfer rate constraints of 1.8 ± 1.1 h −1 from central to peripheral compartments and 0.7 ± 0.3 h −1 from peripheral to central compartments. For the simulated intermittent dosing regimens, on average, the median trough concentration reduced by 50% for every 40-mL/min/1.73 m 2 increase in urinary creatinine clearance. Simulated doses of at least 6 g/day were required for some levels of augmented renal clearance. Conclusions Patients with severe traumatic brain injury and aneurysmal subarachnoid hemorrhage with augmented renal clearance are at risk of not achieving target levetiracetam plasma concentrations. We suggest dose titration guided by measured creatinine clearance, and/or, therapeutic drug monitoring if available, to minimize the risk of seizures.
Postnatal Development of Arteriovenous Malformations
Background: Arteriovenous malformations (AVMs) are commonly thought to be congenital malformations; however, patients usually present in adolescence or adulthood. This study was carried out to better understand the development of AVMs between birth and presentation. Methods: A retrospective review was performed of the medical records of all patients under 25 presenting to a single institution with an AVM or spontaneous intracerebral hemorrhage from 2000 to 2007. Results: Out of a total of 34 cases, 3 children were identified with delayed de novo appearance of an AVM after an intracerebral hemorrhage and normal initial angiography. The clinical and angiographic features are presented for these 3 patients and for an additional patient with AVM recurrence after complete surgical excision. Conclusions: In the light of these cases and a review of the literature, we suggest a hypothesis that AVMs develop postnatally, undergoing a period of growth in childhood or early adulthood, and that they may become symptomatic from the time of their earliest development. The trigger to growth may be shear stress stimulating growth factor expression by endothelial cells lining an arteriovenous fistula. Alternative stimuli, such as venous hypertension, cannot be ruled out.