ORCID Profile
0000-0002-9724-4540
Current Organisation
QIMR Berghofer Medical Research Institute
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Publisher: MDPI AG
Date: 06-02-2019
Abstract: Glioblastomas are the most common and lethal neoplasms of the central nervous system. Neighbouring glioma cells maintain extreme degrees of genetic and phenotypic variation that form intratumoural heterogeneity. This genetic ersity allows the most adaptive tumour clones to develop treatment resistance, ultimately leading to disease recurrence. We aimed to model this phenomenon and test the effectiveness of several targeted therapeutic interventions to overcome therapy resistance. Heterogeneous tumour masses were first deconstructed into single tumour cells, which were expanded independently as single-cell clones. Single nucleotide polymorphism arrays, whole-genome and RNA sequencing, and CpG methylation analysis validated the unique molecular profile of each tumour clone, which displayed distinct pathologic features, including cell morphology, growth rate, and resistance to temozolomide and ionizing radiation. We also identified variable sensitivities to AURK, CDK, and EGFR inhibitors which were consistent with the heterogeneous molecular alterations that each clone harboured. These targeted therapies effectively eliminated the temozolomide- and/or irradiation-resistant clones and also parental polyclonal cells. Our findings indicate that polyclonal tumours create a dynamic environment that consists of erse tumour elements and treatment responses. Designing targeted therapies based on a range of molecular profiles can be a more effective strategy to eradicate treatment resistance, recurrence, and metastasis.
Publisher: Oxford University Press (OUP)
Date: 30-08-2020
Abstract: Despite significant endeavor having been applied to identify effective therapies to treat glioblastoma (GBM), survival outcomes remain intractable. The greatest nonsurgical benefit arises from radiotherapy, though tumors typically recur due to robust DNA repair. Patients could therefore benefit from therapies with the potential to prevent DNA repair and synergize with radiotherapy. In this work, we investigated the potential of salinomycin to enhance radiotherapy and further uncover novel dual functions of this ionophore to induce DNA damage and prevent repair. In vitro primary GBM models and ex vivo GBM patient explants were used to determine the mechanism of action of salinomycin by immunoblot, flow cytometry, immunofluorescence, immunohistochemistry, and mass spectrometry. In vivo efficacy studies were performed using orthotopic GBM animal xenograft models. Salinomycin derivatives were synthesized to increase drug efficacy and explore structure-activity relationships. Here we report novel dual functions of salinomycin. Salinomycin induces toxic DNA lesions and prevents subsequent recovery by targeting homologous recombination (HR) repair. Salinomycin appears to target the more radioresistant GBM stem cell–like population and synergizes with radiotherapy to significantly delay tumor formation in vivo. We further developed salinomycin derivatives which display greater efficacy in vivo while retaining the same beneficial mechanisms of action. Our findings highlight the potential of salinomycin to induce DNA lesions and inhibit HR to greatly enhance the effect of radiotherapy. Importantly, first-generation salinomycin derivatives display greater efficacy and may pave the way for clinical testing of these agents.
Publisher: Springer Science and Business Media LLC
Date: 14-09-2014
DOI: 10.1038/NSMB.2890
Publisher: Cold Spring Harbor Laboratory
Date: 16-02-2022
DOI: 10.1101/2022.02.14.480293
Abstract: Recurrence after therapy is the primary life-threatening complication of medulloblastoma. In Sonic Hedgehog (SHH)-subgroup medulloblastoma, OLIG2-expressing tumour stem cells are crucial to recurrence. We investigated the potential of the small-molecule OLIG2 inhibitor CT-179 to decrease recurrence in patient-derived organoids, mice genetically-engineered to develop SHH-driven MB, and mice with MB patient-derived xenograft (PDX) tumours. We found that OLIG2 mRNA significantly correlated with poor survival in patients with SHH-MB, but not other subgroups. CT-179 rapidly downregulated OLIG2 protein in vitro and displayed nanomolar IC 50 values. CT-179 arrested MB cells at G 2 /M, with degradation of cyclin B1 and phospho-CDK1 inducing apoptosis. In vivo CT-179 induced similar cell cycle changes in MBs in Smo -mutant mice and significantly increased mouse survival. In both MB organoids and mouse models, CT-179 combined with radiotherapy showed greater efficacy than either treatment alone. These data highlight the potential for OLIG2-targeted therapy to improve MB outcomes by targeting recurrent disease.
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.CELREP.2014.07.036
Abstract: Regulatory protein phosphorylation controls normal and pathophysiological signaling in eukaryotic cells. Despite great advances in mass-spectrometry-based proteomics, the extent, localization, and site-specific stoichiometry of this posttranslational modification (PTM) are unknown. Here, we develop a stringent experimental and computational workflow, capable of mapping more than 50,000 distinct phosphorylated peptides in a single human cancer cell line. We detected more than three-quarters of cellular proteins as phosphoproteins and determined very high stoichiometries in mitosis or growth factor signaling by label-free quantitation. The proportion of phospho-Tyr drastically decreases as coverage of the phosphoproteome increases, whereas Ser/Thr sites saturate only for technical reasons. Tyrosine phosphorylation is maintained at especially low stoichiometric levels in the absence of specific signaling events. Unexpectedly, it is enriched on higher-abundance proteins, and this correlates with the substrate KM values of tyrosine kinases. Our data suggest that P-Tyr should be considered a functionally separate PTM of eukaryotic proteomes.
Publisher: Springer Science and Business Media LLC
Date: 15-06-2015
DOI: 10.1038/NCOMMS8289
Publisher: MDPI AG
Date: 13-07-2020
DOI: 10.3390/F11070754
Abstract: The accurate prediction of the volume of standing trees is a prerequisite for planning and decision making in sustainable forest management. In Nepal, limited information on form factor (i.e. the ratio of the volume of a tree to the product of its basal area and height) is available for economically important tree species. Thus, current management plans consider a simple approximation for all species irrespective of their height and diameter, which h ers the estimation of a sustainable harvest rate. Therefore, this study elaborates the form factor for Sal (Shorea robusta), an economically valuable tree of Nepal based on a random selection of 100 in idual trees representing a wide range of diameters between 10 and 100 cm. Diameter and bark thickness were measured at every 1-meter interval of the length of the stem and branches until the diameter reached 10 cm. The analysis allowed for the estimation of an average form factor for Sal wood with 0.407 over bark and 0.336 under bark, while the form factor for the stem was 0.335 over bark and 0.281 under bark. The results indicate an increasing form factor until 70 cm diameter and a decreasing value for larger diameters, because of the large crowns of the mature Sal trees. We conclude that the default form factor of Sal (0.5) used in management planning results in an overestimation of standing tree volume. Using form factor according to diameter classes will allow a more accurate prediction of the standing volume.
Publisher: Elsevier BV
Date: 05-2012
Publisher: Oxford University Press (OUP)
Date: 04-2004
Publisher: Springer Science and Business Media LLC
Date: 20-03-2019
DOI: 10.1038/S41598-019-41277-Z
Abstract: 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- erse, 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.
Publisher: MDPI AG
Date: 24-08-2020
DOI: 10.3390/F11090923
Abstract: The authors found some minus signs were omitted in Table 4 and the Equations (1) and (8), and have requested that the following changes be made to their paper [...]
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.CELREP.2015.04.018
Abstract: The liver maintains glucose and lipid homeostasis by adapting its metabolic activity to the energy needs of the organism. Communication between hepatocytes and extracellular environment via endocytosis is key to such homeostasis. Here, we addressed the question of whether endosomes are required for gluconeogenic gene expression. We took advantage of the loss of endosomes in the mouse liver upon Rab5 silencing. Strikingly, we found hepatomegaly and severe metabolic defects such as hypoglycemia, hypercholesterolemia, hyperlipidemia, and glycogen accumulation that phenocopied those found in von Gierke's disease, a glucose-6-phosphatase (G6Pase) deficiency. G6Pase deficiency alone can account for the reduction in hepatic glucose output and glycogen accumulation as determined by mathematical modeling. Interestingly, we uncovered functional alterations in the transcription factors, which regulate G6Pase expression. Our data highlight a requirement of Rab5 and the endosomal system for the regulation of gluconeogenic gene expression that has important implications for metabolic diseases.
Publisher: Humana Press
Date: 2008
DOI: 10.1007/978-1-60327-517-0_30
Abstract: Deciphering the differentiation pathway of embryonic stem (ES) cells is a challenging task not only for basic research, but also for clinicians who intend to use ES cells for cell transplantation approaches. We have shown that reactive oxygen species (ROS) play a primordial role in the differentiation of mouse ES cells toward the cardiovascular cell lineage. During differentiation, ES cells robustly generate ROS, which interfere with signaling pathways that direct cardiac and vascular commitment. Differentiating ES cells expression of Nox-1, Nox-2, and Nox-4 has been demonstrated. We have shown that mechanical strain application to embyoid bodies grown from ES cells initiates the cardiovascular differentiation program. Under these conditions, a burst of ROS generation occurs which is followed by induction of Nox-1 and Nox-4 and a feed-forward upregulation of ROS production.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 22-07-2014
DOI: 10.1126/SCISIGNAL.2004856
Abstract: Proteomics analysis of TGF-β signaling in keratinocytes reveals widespread changes in protein phosphorylation and abundance.
Publisher: American Chemical Society (ACS)
Date: 26-10-2010
DOI: 10.1021/PR100637Q
Abstract: Mass spectrometry (MS)-based proteomics now enables the analysis of thousands of phosphorylation sites in single projects. Among a wide range of analytical approaches, the combination of high resolution MS scans in an Orbitrap analyzer with low resolution MS/MS scans in a linear ion trap has proven to be particularly successful ("high-low" strategy). Here we investigate if the improved sensitivity of higher energy collisional dissociation (HCD) on an LTQ-Orbitrap Velos instrument allows a "high-high" strategy. A high resolution MS scan was followed by up to 10 HCD MS/MS scans, and we achieved cycle times of about 3 s making the method compatible with chromatographic time scales. Fragment mass accuracy increased about 50-fold compared to the "high-low" strategy. Unexpectedly, the HCD approach mapped up to 16,000 total phosphorylation sites in one day's measuring time--the same or better than the standard high-low strategy. Reducing the target values from a standard of 30,000 to 5000 ions did not severely affect identification rates but did decrease identification and localization scores for phosphorylation sites. We conclude that HCD in the new configuration is now a viable method for large-scale phosphoproteome analysis alongside collisional induced dissociation, (CID) and electron capture/transfer dissociation (ECD/ETD).
Publisher: American Chemical Society (ACS)
Date: 21-05-2012
DOI: 10.1021/PR3003886
Publisher: Springer Science and Business Media LLC
Date: 28-08-2019
Publisher: MDPI AG
Date: 21-01-2020
DOI: 10.3390/CELLS9020267
Abstract: 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 in idual 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.
Start Date: 2017
End Date: 2018
Funder: Cure Cancer Australia
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