ORCID Profile
0000-0002-0567-5918
Current Organisation
Childrens Cancer Institute of Australia for Medical Research
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Publisher: Impact Journals, LLC
Date: 04-2016
Abstract: The anti-apoptotic protein B cell lymphoma/leukaemia 2 (BCL-2) is highly expressed in neuroblastoma and plays an important role in oncogenesis. In this study, the selective BCL-2 inhibitor ABT199 was tested in a panel of neuroblastoma cell lines with erse expression levels of BCL-2 and other BCL-2 family proteins. ABT199 caused apoptosis more potently in neuroblastoma cell lines expressing high BCL-2 and BIM/BCL-2 complex levels than low expressing cell lines. Effects on cell viability correlated with effects on BIM displacement from BCL-2 and cytochrome c release from the mitochondria. ABT199 treatment of mice with neuroblastoma tumors expressing high BCL-2 levels only resulted in growth inhibition, despite maximum BIM displacement from BCL-2 and the induction of a strong apoptotic response. We showed that neuroblastoma cells might survive ABT199 treatment due to its acute upregulation of the anti-apoptotic BCL-2 family protein myeloid cell leukaemia sequence 1 (MCL-1) and BIM sequestration by MCL-1. In vitro inhibition of MCL-1 sensitized neuroblastoma cell lines to ABT199, confirming the pivotal role of MCL-1 in ABT199 resistance. Our findings suggest that neuroblastoma patients with high BCL-2 and BIM/BCL-2 complex levels might benefit from combination treatment with ABT199 and compounds that inhibit MCL-1 expression.
Publisher: American Association for Cancer Research (AACR)
Date: 21-08-2023
DOI: 10.1158/0008-5472.24000213.V1
Abstract: Supplementary Figures 1-7 and Figure Legends
Publisher: Elsevier BV
Date: 09-2020
DOI: 10.1016/J.EJCA.2020.05.010
Abstract: Only one class of targeted agents (anti-GD2 antibodies) has been incorporated into front-line therapy for neuroblastoma since the 1980s. The Neuroblastoma New Drug Development Strategy (NDDS) initiative commenced in 2012 to accelerate the development of new drugs for neuroblastoma. Advances have occurred, with eight of nine high-priority targets being evaluated in paediatric trials including anaplastic lymphoma kinase inhibitors being investigated in front-line, but significant challenges remain. This article reports the conclusions of the second NDDS forum, which expanded across the Atlantic to further develop the initiative. Pre-clinical and clinical data for 40 genetic targets and mechanisms of action were prioritised and drugs were identified for early-phase trials. Strategies to develop drugs targeting TERT, telomere maintenance, ATRX, alternative lengthening of telomeres (ALT), BRIP1 and RRM2 as well as direct targeting of MYCN are high priority and should be ch ioned for drug discovery. Promising pre-clinical data suggest that targeting of ALT by ATM or PARP inhibition may be potential strategies. Drugs targeting CDK2/9, CDK7, ATR and telomere maintenance should enter paediatric clinical development rapidly. Optimising the response to anti-GD2 by combinations with chemotherapy, targeted agents and other immunological targets are crucial. Delivering this strategy in the face of small patient cohorts, genomically defined subpopulations and a large number of permutations of combination trials, demands even greater international collaboration. In conclusion, the NDDS provides an internationally agreed, biologically driven selection of prioritised genetic targets and drugs. Improvements in the strategy for conducting trials in neuroblastoma will accelerate bringing these new drugs more rapidly to front-line therapy.
Publisher: Springer Science and Business Media LLC
Date: 19-11-2018
DOI: 10.1038/S41467-018-06699-9
Abstract: Chromosome 17q gains are almost invariably present in high-risk neuroblastoma cases. Here, we perform an integrative epigenomics search for dosage-sensitive transcription factors on 17q marked by H3K27ac defined super-enhancers and identify TBX2 as top candidate gene. We show that TBX2 is a constituent of the recently established core regulatory circuitry in neuroblastoma with features of a cell identity transcription factor, driving proliferation through activation of p21-DREAM repressed FOXM1 target genes. Combined MYCN/TBX2 knockdown enforces cell growth arrest suggesting that TBX2 enhances MYCN sustained activation of FOXM1 targets. Targeting transcriptional addiction by combined CDK7 and BET bromodomain inhibition shows synergistic effects on cell viability with strong repressive effects on CRC gene expression and p53 pathway response as well as several genes implicated in transcriptional regulation. In conclusion, we provide insight into the role of the TBX2 CRC gene in transcriptional dependency of neuroblastoma cells warranting clinical trials using BET and CDK7 inhibitors.
Publisher: American Association for Cancer Research (AACR)
Date: 21-08-2023
DOI: 10.1158/0008-5472.24000210
Abstract: Supplementary Figures
Publisher: American Association for the Advancement of Science (AAAS)
Date: 15-07-2022
Abstract: High-risk neuroblastoma, a pediatric tumor originating from the sympathetic nervous system, has a low mutation load but highly recurrent somatic DNA copy number variants. Previously, segmental gains and/or lifications allowed identification of drivers for neuroblastoma development. Using this approach, combined with gene dosage impact on expression and survival, we identified ribonucleotide reductase subunit M2 (RRM2) as a candidate dependency factor further supported by growth inhibition upon in vitro knockdown and accelerated tumor formation in a neuroblastoma zebrafish model coexpressing human RRM2 with MYCN. Forced RRM2 induction alleviates excessive replicative stress induced by CHK1 inhibition, while high RRM2 expression in human neuroblastomas correlates with high CHK1 activity. MYCN-driven zebrafish tumors with RRM2 co-overexpression exhibit differentially expressed DNA repair genes in keeping with enhanced ATR-CHK1 signaling activity. In vitro, RRM2 inhibition enhances intrinsic replication stress checkpoint addiction. Last, combinatorial RRM2-CHK1 inhibition acts synergistic in high-risk neuroblastoma cell lines and patient-derived xenograft models, illustrating the therapeutic potential.
Publisher: American Association for Cancer Research (AACR)
Date: 31-07-2023
DOI: 10.1158/0008-5472.23808560.V1
Abstract: Supplementary Figures
Publisher: Springer Science and Business Media LLC
Date: 02-06-2020
Publisher: American Association for Cancer Research (AACR)
Date: 31-07-2023
DOI: 10.1158/0008-5472.23808560
Abstract: Supplementary Figures
Publisher: American Association for Cancer Research (AACR)
Date: 21-08-2023
DOI: 10.1158/0008-5472.24000213
Abstract: Supplementary Figures 1-7 and Figure Legends
Publisher: Springer Science and Business Media LLC
Date: 29-06-2015
DOI: 10.1038/NG.3333
Publisher: American Association for Cancer Research (AACR)
Date: 21-08-2023
DOI: 10.1158/0008-5472.24000207.V1
Abstract: Supplementary Materials and Methods
Publisher: Elsevier BV
Date: 02-2012
DOI: 10.1016/J.JCONREL.2011.08.041
Abstract: The anticancer drug imatinib is an inhibitor of the platelet-derived growth factor receptor (PDGFR) kinases, which are involved in the pathogenesis of fibrotic diseases. In the current study we investigated the delivery of imatinib to the proximal tubular cells of the kidneys and evaluated the potential antifibrotic effects of imatinib in tubulointerstitial fibrosis. Coupling of imatinib to the low molecular weight protein lysozyme via the platinum (II)-based linker ULS yielded a 0.8:1 drug-carrier conjugate that rapidly accumulated in the proximal tubular cells upon intravenous and intraperitoneal administration. The bioavailability of intraperitoneally administered imatinib-ULS-lysozyme was 100%. Renal imatinib levels persisted for up to 3 days after a single injection of imatinib-ULS-lysozyme. Compared with an equal dose imatinib mesylate, imatinib-ULS-lysozyme resulted in a 30- and 15-fold higher renal exposure of imatinib, for intravenous and intraperitoneal administration respectively. Imatinib-ULS-lysozyme could not be detected in the heart, which is the organ at risk for side-effects of prolonged treatment with imatinib. The efficacy of imatinib-ULS-lysozyme in the treatment of tubulointerstitial fibrosis was evaluated in the unilateral ureteral obstruction (UUO) model in mice. Three days UUO resulted in all signs of early fibrosis, i.e. an increased deposition of matrix and production of profibrotic factors. Although a moderately increased activity of PDGFR-β was observed, the profibrotic phenotype could not be inhibited with imatinib mesylate or with imatinib-ULS-lysozyme. Further evaluation of imatinib mesylate and imatinib-ULS-lysozyme is therefore warranted in an animal model of renal disease in which the activation of PDGFR-β is more pronounced.
Publisher: Public Library of Science (PLoS)
Date: 30-12-2015
Publisher: American Chemical Society (ACS)
Date: 31-03-2011
DOI: 10.1021/BC1005637
Abstract: Multikinase inhibitors are potent anticancer drugs that simultaneously intervene in multiple related signaling cascades, thus being capable of blocking salvage pathways that may play a role in the development of drug resistance. Multikinase inhibitors are increasingly evaluated for indications other than cancer, but long-term safety risks dictated by off-organ toxicities of these agents may prevent their safe and effective use. Here, we describe a new approach in which platinum coordination chemistry is applied for the development of a cell-selective multikinase inhibitor bioconjugate. The platinum(II) kinase inhibitor bioconjugate was designed to be active with the linker attached to the inhibitor and displayed improved activity by enhanced cell specificity as well as enhanced intracellular retention, thereby prolonging its pharmacological activity. In addition, the utilized platinum-based linkage technology potentiated the inhibitory activity of the multikinase inhibitor. These features in combination with carrier-mediated uptake in the target cells may revolutionize dosing regimens and safety profiles of (multi)kinase inhibitors.
Publisher: Elsevier BV
Date: 03-2015
DOI: 10.1016/J.JPBA.2015.01.026
Abstract: A quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay for GSK2126458, a dual PI3K/mTOR inhibitor, was developed and validated. Plasma and tumor homogenate s les were pre-treated using protein precipitation with acetonitrile containing dabrafenib as internal standard. After dilution with water, the extract was directly injected into the reversed-phase liquid chromatographic system. The eluate was transferred into the electrospray interface with positive ionization and compounds were detected in the selected reaction monitoring mode of a triple quadrupole mass spectrometer. The assay was completely validated for plasma in a 4-4000 ng/ml calibration range with r(2)=0.9996±0.0003 using double logarithmic calibration (n=5). Within-run precisions (n=6) were 2.0-5.3% and between-run (3 runs n=18) precisions 2.7-5.8%. Accuracies were between 101 and 105% for the whole calibration range. The drug was sufficiently stable under all relevant analytical conditions. Finally, the assay was successfully applied to determine plasma and tumor drug levels after oral administration of GSK2126458 to mice with AMC711T neuroblastoma xenografts.
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.JPBA.2013.08.051
Abstract: A quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay for the cyclin-dependent kinase inhibitor AT7519 in mouse plasma was developed and validated. Plasma s les were pre-treated using protein precipitation with acetonitrile containing rucaparib as internal standard. After dilution with water, the extract was directly injected into the reversed-phase LC system. The eluate was transferred into the electrospray interface with positive ionization and the analyte was detected in the selected reaction monitoring mode of a triple quadrupole mass spectrometer. The assay was validated in a 5-10,000ng/ml calibration range using double logarithmic calibration, 5ng/ml was the lower limit of quantification. Within day precisions (n=6) were 2.9-5.6%, between day (3 days n=18) precisions 3.2-7.2%. Accuracies were between 95.9 and 99.0% for the whole calibration range. The drug was stable under all relevant analytical conditions. Finally, the assay was successfully used to determine plasma pharmacokinetics after intraperitoneal administration of AT7519 in mice with neuroblastoma xenografts.
Publisher: American Association for Cancer Research (AACR)
Date: 21-08-2023
DOI: 10.1158/0008-5472.C.6767498
Abstract: Abstract For one-third of patients with pediatric cancer enrolled in precision medicine programs, molecular profiling does not result in a therapeutic recommendation. To identify potential strategies for treating these high-risk pediatric patients, we performed i in vitro /i screening of 125 patient-derived s les against a library of 126 anticancer drugs. Tumor cell expansion did not influence drug responses, and 82% of the screens on expanded tumor cells were completed while the patients were still under clinical care. High-throughput drug screening (HTS) confirmed known associations between activating genomic alterations in i NTRK /i , i BRAF /i , and i ALK /i and responses to matching targeted drugs. The i in vitro /i results were further validated in patient-derived xenograft models i in vivo /i and were consistent with clinical responses in treated patients. In addition, effective combinations could be predicted by correlating sensitivity profiles between drugs. Furthermore, molecular integration with HTS identified biomarkers of sensitivity to WEE1 and MEK inhibition. Incorporating HTS into precision medicine programs is a powerful tool to accelerate the improved identification of effective biomarker-driven therapeutic strategies for treating high-risk pediatric cancers. Significance: Integrating HTS with molecular profiling is a powerful tool for expanding precision medicine to support drug treatment recommendations and broaden the therapeutic options available to high-risk pediatric cancers. /
Publisher: American Association for Cancer Research (AACR)
Date: 31-07-2023
DOI: 10.1158/0008-5472.CAN-22-3702
Abstract: Integrating HTS with molecular profiling is a powerful tool for expanding precision medicine to support drug treatment recommendations and broaden the therapeutic options available to high-risk pediatric cancers.
Publisher: Elsevier BV
Date: 09-2020
Publisher: Wiley
Date: 13-10-2011
Abstract: The development of a macromolecular conjugate of a multitargeted tyrosine kinase inhibitor is described that can be used for renal-specific delivery into proximal tubular cells. A novel sunitinib analogue, that is, 17864, is conjugated to a NH(2) -PAMAM-G3 dendrimer via the platinum (II)-based Universal Linkage System (ULS™). The activity of 17864 is retained after coordination to the ULS linker alone or when coupled to NH(2) -PAMAM-G3. 17864-UlS-NH(2) -PAMAM-G3 is non-toxic to proximal tubular cells in vitro. After intravenous administration to mice, 17864-UlS-NH(2) -PAMAM-G3 rapidly and efficiently accumulates in the kidneys. These results are encouraging for future studies focusing on the development of novel therapeutics for the treatment of renal diseases.
Publisher: American Association for Cancer Research (AACR)
Date: 15-08-2023
DOI: 10.1158/0008-5472.23952251
Abstract: Supplementary Figures
Publisher: American Association for Cancer Research (AACR)
Date: 31-07-2023
DOI: 10.1158/0008-5472.C.6767498.V1
Abstract: Abstract For one-third of patients with pediatric cancer enrolled in precision medicine programs, molecular profiling does not result in a therapeutic recommendation. To identify potential strategies for treating these high-risk pediatric patients, we performed i in vitro /i screening of 125 patient-derived s les against a library of 126 anticancer drugs. Tumor cell expansion did not influence drug responses, and 82% of the screens on expanded tumor cells were completed while the patients were still under clinical care. High-throughput drug screening (HTS) confirmed known associations between activating genomic alterations in i NTRK /i , i BRAF /i , and i ALK /i and responses to matching targeted drugs. The i in vitro /i results were further validated in patient-derived xenograft models i in vivo /i and were consistent with clinical responses in treated patients. In addition, effective combinations could be predicted by correlating sensitivity profiles between drugs. Furthermore, molecular integration with HTS identified biomarkers of sensitivity to WEE1 and MEK inhibition. Incorporating HTS into precision medicine programs is a powerful tool to accelerate the improved identification of effective biomarker-driven therapeutic strategies for treating high-risk pediatric cancers. Significance: Integrating HTS with molecular profiling is a powerful tool for expanding precision medicine to support drug treatment recommendations and broaden the therapeutic options available to high-risk pediatric cancers. /
Publisher: Elsevier BV
Date: 11-2012
DOI: 10.1016/J.EJPHAR.2012.08.010
Abstract: The Rho kinase pathway plays an important role in epithelial dedifferentiation and inflammatory cell infiltration. Recent studies suggest that inflammation promotes lymphangiogenesis, which has been associated with renal allograft rejection. We investigated whether targeted inhibition of the Rho kinase pathway in proximal tubular cells reduces inflammation and lymphangiogenesis in acute renal allograft rejection. The Rho kinase inhibitor Y27632 was coupled to lysozyme (Y27632-lysozyme), providing a kidney-specific conjugate that can release its drug in proximal tubular cells. Isogenic (Fisher-Fisher, n=18), or allogenic (Fisher-Lewis, n=24) kidney transplantations were performed, with the contralateral kidney remaining in situ. To elicit acute rejection, no immunosuppressive treatment was given. Animals were treated daily with Y27632-lysozyme (10 mg/kg/day i.v.) or vehicle (saline i.v.) until sacrifice (1 or 4 days post-transplantation). After allogenic transplantation, interstitial macrophage accumulation was strongly reduced by Y27632-lysozyme at day 4 after transplantation. Interstitial lymphangiogenesis, which was induced in allografts as compared to control kidney, was also reduced by renal Rho kinase inhibition at day 4 after transplantation. The increase of vimentin and procollagen-1alpha1 gene expression in renal allografts from day 1 to day 4 after transplantation was significantly reduced by Y27632-lysozyme. Y27632-lysozyme did not affect systolic blood pressure in isogenic or allogenic transplantation groups. In cultured tubular epithelial cells (NRK-52E), Rho kinase inhibition dose-dependently reduced IL-1β-induced MCP-1 gene expression. Renal inhibition of Rho kinase causes a marked reduction in renal inflammation and renal lymphangiogenesis during acute transplant rejection, suggesting that this treatment regimen is a valuable future treatment in renal transplantation.
Publisher: Springer Science and Business Media LLC
Date: 11-03-2020
DOI: 10.1038/S41467-020-15155-6
Abstract: Kidney tumours are among the most common solid tumours in children, comprising distinct subtypes differing in many aspects, including cell-of-origin, genetics, and pathology. Pre-clinical cell models capturing the disease heterogeneity are currently lacking. Here, we describe the first paediatric cancer organoid biobank. It contains tumour and matching normal kidney organoids from over 50 children with different subtypes of kidney cancer, including Wilms tumours, malignant rhabdoid tumours, renal cell carcinomas, and congenital mesoblastic nephromas. Paediatric kidney tumour organoids retain key properties of native tumours, useful for revealing patient-specific drug sensitivities. Using single cell RNA-sequencing and high resolution 3D imaging, we further demonstrate that organoid cultures derived from Wilms tumours consist of multiple different cell types, including epithelial, stromal and blastemal-like cells. Our organoid biobank captures the heterogeneity of paediatric kidney tumours, providing a representative collection of well-characterised models for basic cancer research, drug-screening and personalised medicine.
Publisher: Springer Science and Business Media LLC
Date: 05-10-2020
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 07-2011
DOI: 10.1016/J.ACA.2011.04.050
Abstract: Drug-protein conjugates have been widely used for the cell-specific targeting of drugs to cells that can bind and internalize the proteinaceous carrier. For renal drug targeting, lysozyme (LZM) can be used as an effective carrier that accumulates in proximal tubular cells. We used capillary electrophoresis-time-of-flight mass spectrometry (CE-TOF-MS) for the characterization of different drug-LZM conjugates. A recently developed prototype porous tip sprayer was employed for sheathless electrospray ionization (ESI) CE-MS interfacing. In order to prevent adsorption of LZM conjugates to the capillary wall, a positively charged polyethylenimine capillary coating was used in combination with a low-pH background electrolyte. Drug-LZM products had been prepared by first coupling BOC-l-methionine hydroxysuccinimide ester (BOCmet) to lysine residues of LZM followed by conjugation with the kinase inhibitors LY364947, erlotinib, or Y27632 via a platinum(II)-based linker. CE-TOF-MS of each preparation showed narrow symmetrical peaks for the various reaction products demonstrating that drug-LZM conjugates remained stable during the CE analysis and subsequent ESI. Components observed in the drug-LZM products were assigned based on their relative migration times and on molecular mass as obtained by TOF-MS. The TOF-MS data obtained for the in idual components revealed that the preparations contained LZM carrying one or two drug molecules, next to unmodified and BOCmet-modified LZM. Based on relative peak areas (assuming an equimolar response for each component) a quantitative conjugate profile could be derived for every preparation leading to drug loading values of 0.4-0.6 mol drug per mole protein.
Publisher: American Association for Cancer Research (AACR)
Date: 21-08-2023
DOI: 10.1158/0008-5472.24000210.V1
Abstract: Supplementary Figures
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2014
Publisher: Wiley
Date: 24-08-2020
DOI: 10.1002/JHA2.81
Publisher: Springer Science and Business Media LLC
Date: 11-12-2018
DOI: 10.1038/S41388-018-0595-3
Abstract: ALK mutations occur in 10% of primary neuroblastomas and represent a major target for precision treatment. In combination with MYCN lification, ALK mutations infer an ultra-high-risk phenotype resulting in very poor patient prognosis. To open up opportunities for future precision drugging, a deeper understanding of the molecular consequences of constitutive ALK signaling and its relationship to MYCN activity in this aggressive pediatric tumor entity will be essential. We show that mutant ALK downregulates the 'HMG-box transcription factor 1' (HBP1) through the PI
Publisher: Ferrata Storti Foundation (Haematologica)
Date: 07-05-2020
Publisher: Elsevier BV
Date: 02-0055
DOI: 10.1016/J.EJCA.2013.11.015
Abstract: Recently protocols have been devised for the culturing of cell lines from fresh tumours under serum-free conditions in defined neural stem cell medium. These cells, frequently called tumour initiating cells (TICs) closely retained characteristics of the tumours of origin. We report the isolation of eight newly-derived neuroblastoma TICs from six primary neuroblastoma tumours and two bone marrow metastases. The primary tumours from which these TICs were generated have previously been fully typed by whole genome sequencing (WGS). Array comparative genomic hybridisation (aCGH) analysis showed that TIC lines retained essential characteristics of the primary tumours and exhibited typical neuroblastoma chromosomal aberrations such as MYCN lification, gain of chromosome 17q and deletion of 1p36. Protein analysis showed expression for neuroblastoma markers MYCN, NCAM, CHGA, DBH and TH while haematopoietic markers CD19 and CD11b were absent. We analysed the growth characteristics and confirmed tumour-forming potential using sphere-forming assays, subcutaneous and orthotopic injection of these cells into immune-compromised mice. Affymetrix mRNA expression profiling of TIC line xenografts showed an expression pattern more closely mimicking primary tumours compared to xenografts from classical cell lines. This establishes that these neuroblastoma TICs cultured under serum-free conditions are relevant and useful neuroblastoma tumour models.
Publisher: American Association for Cancer Research (AACR)
Date: 21-08-2023
DOI: 10.1158/0008-5472.24000207
Abstract: Supplementary Materials and Methods
Publisher: Elsevier BV
Date: 12-2008
DOI: 10.1016/J.JCONREL.2008.08.013
Abstract: Cell-specific targeting to renal tubular cells is an interesting approach to enhance the accumulation of drugs in the kidney. Low molecular weight proteins are rapidly filtered and extensively accumulate in proximal tubular cells. We therefore have used lysozyme (LZM, 14 kDa) as a tubular cell-specific carrier for the delivery of kinase inhibitors. Two different kinase inhibitors (LY364947 and erlotinib, directed to either the TGF-beta receptor kinase or the EGF receptor) were in idually conjugated to LZM via a novel platinum-based linker (Universal Linkage System ULS). The cellular handling and pharmacological efficacy of the conjugates were evaluated in cultured proximal tubular cells (HK-2 cells). Both conjugates were efficiently internalized via endocytosis. TGF-beta or EGF activated HK-2 cells showed a strong activation of the studied kinases and the conjugates inhibited these events, as was demonstrated by Western blotting of phosphorylated downstream mediators and quantitative gene expression analysis. In conclusion, we have developed tubular cell-specific kinase inhibitor-LZM conjugates via a novel linker strategy, which both showed to be effective in vitro. Future in vivo studies should show their potential for the treatment of renal diseases.
Publisher: American Association for Cancer Research (AACR)
Date: 21-08-2023
DOI: 10.1158/0008-5472.24000204.V1
Abstract: Supplementary Tables S1-S7
Publisher: Elsevier BV
Date: 04-2017
DOI: 10.1016/J.EJCA.2016.12.019
Abstract: Neuroblastoma is predominantly characterised by chromosomal rearrangements. Next to V-Myc Avian Myelocytomatosis Viral Oncogene Neuroblastoma Derived Homolog (MYCN) lification, chromosome 7 and 17q gains are frequently observed. We identified a neuroblastoma patient with a regional 7q36 gain, encompassing the enhancer of zeste homologue 2 (EZH2) gene. EZH2 is the histone methyltransferase of lysine 27 of histone H3 (H3K27me3) that forms the catalytic subunit of the polycomb repressive complex 2. H3K27me3 is commonly associated with the silencing of genes involved in cellular processes such as cell cycle regulation, cellular differentiation and cancer. High EZH2 expression correlated with poor prognosis and overall survival independent of MYCN lification status. Unexpectedly, treatment of 3 EZH2-high expressing neuroblastoma cell lines (IMR32, CHP134 and NMB), with EZH2-specific inhibitors (GSK126 and EPZ6438) resulted in only a slight G1 arrest, despite maximum histone methyltransferase activity inhibition. Furthermore, colony formation in cell lines treated with the inhibitors was reduced only at concentrations much higher than necessary for complete inhibition of EZH2 histone methyltransferase activity. Knockdown of the complete protein with three independent shRNAs resulted in a strong apoptotic response and decreased cyclin D1 levels. This apoptotic response could be rescued by overexpressing EZH2ΔSET, a truncated form of wild-type EZH2 lacking the SET transactivation domain necessary for histone methyltransferase activity. Our findings suggest that high EZH2 expression, at least in neuroblastoma, has a survival function independent of its methyltransferase activity. This important finding highlights the need for studies on EZH2 beyond its methyltransferase function and the requirement for compounds that will target EZH2 as a complete protein.
Publisher: American Association for Cancer Research (AACR)
Date: 21-08-2023
DOI: 10.1158/0008-5472.24000204
Abstract: Supplementary Tables S1-S7
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.JPBA.2014.01.011
Abstract: A quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay for sepantronium bromide (YM155), an inhibitor of survivin, was developed and validated. Under reduced light exposure, plasma s les were pre-treated using protein precipitation with acetonitrile containing AT7519 as internal standard. After dilution with water, the extract was directly injected into the reversed-phase liquid chromatographic system. The eluate was transferred into the electrospray interface with positive ionization and compounds detected in the selected reaction monitoring mode of a triple quadrupole mass spectrometer. The assay was validated in a 0.5-100ng/ml calibration range with r(2)=0.9981±0.0007 using double logarithmic calibration (n=5). Within day precisions (n=6) were 3.6-8.8% and between day (3 days n=18) precisions 6.5-11.1%. Accuracies were between 92 and 111% for the whole calibration range. The light sensitive drug sepantronium was sufficiently stable under all relevant analytical conditions. Finally, the assay was successfully used to determine plasma drug levels in mice after administration of sepantronium bromide by continuous infusion from subcutaneously implanted osmotic pumps.
Publisher: Elsevier BV
Date: 30-11-2010
DOI: 10.1016/J.ADDR.2010.07.011
Abstract: Activated signaling cascades in the proximal tubular cells of the kidneys play a crucial role in the development of tubulointerstitial fibrosis. Inhibition of these signaling cascades with locally delivered therapeutics is an attractive approach to minimize the risk of unwanted side effects and to enhance their efficacy within the renal tissue. This review describes the potential avenues to actively target drugs to proximal tubular cells by recognition of internalizing receptors and how drug carriers can reach this cell type from either the apical or basolateral side. Important characteristics of drug carrier systems such as size and charge are discussed, as well as linking technologies that have been used for the coupling of drugs to the presented carrier systems. Lastly, we discuss the cellular handling of drugs by proximal tubular cells after their delivery to the kidneys.
Publisher: American Association for Cancer Research (AACR)
Date: 12-11-2015
DOI: 10.1158/1078-0432.CCR-15-0313
Abstract: Purpose: MYCN-dependent neuroblastomas have low cure rates with current multimodal treatment regimens and novel therapeutic drugs are therefore urgently needed. In previous preclinical studies, we have shown that targeted inhibition of cyclin-dependent kinase 2 (CDK2) resulted in specific killing of MYCN- lified neuroblastoma cells. This study describes the in vivo preclinical evaluation of the CDK inhibitor AT7519. Experimental Design: Preclinical drug testing was performed using a panel of MYCN- lified and MYCN single copy neuroblastoma cell lines and different MYCN-dependent mouse models of neuroblastoma. Results: AT7519 killed MYCN- lified neuroblastoma cell lines more potently than MYCN single copy cell lines with a median LC50 value of 1.7 compared to 8.1 μmol/L (P = 0.0053) and a significantly stronger induction of apoptosis. Preclinical studies in female NMRI homozygous (nu/nu) mice with neuroblastoma patient-derived MYCN- lified AMC711T xenografts revealed dose-dependent growth inhibition, which correlated with intratumoral AT7519 levels. CDK2 target inhibition by AT7519 was confirmed by significant reductions in levels of phosphorylated retinoblastoma (p-Rb) and nucleophosmin (p-NPM). AT7519 treatment of Th-MYCN transgenic mice resulted in improved survival and clinically significant tumor regression (average tumor size reduction of 86% at day 7 after treatment initiation). The improved efficacy of AT7519 observed in Th-MYCN mice correlated with higher tumor exposure to the drug. Conclusions: This study strongly suggests that AT7519 is a promising drug for the treatment of high-risk neuroblastoma patients with MYCN lification. Clin Cancer Res 21(22) 5100–9. ©2015 AACR.
Publisher: American Association for Cancer Research (AACR)
Date: 15-08-2023
DOI: 10.1158/0008-5472.23952251.V1
Abstract: Supplementary Figures
Publisher: Springer Science and Business Media LLC
Date: 07-03-2018
Publisher: American Association for Cancer Research (AACR)
Date: 21-08-2023
DOI: 10.1158/0008-5472.C.6767498.V3
Abstract: Abstract For one-third of patients with pediatric cancer enrolled in precision medicine programs, molecular profiling does not result in a therapeutic recommendation. To identify potential strategies for treating these high-risk pediatric patients, we performed i in vitro /i screening of 125 patient-derived s les against a library of 126 anticancer drugs. Tumor cell expansion did not influence drug responses, and 82% of the screens on expanded tumor cells were completed while the patients were still under clinical care. High-throughput drug screening (HTS) confirmed known associations between activating genomic alterations in i NTRK /i , i BRAF /i , and i ALK /i and responses to matching targeted drugs. The i in vitro /i results were further validated in patient-derived xenograft models i in vivo /i and were consistent with clinical responses in treated patients. In addition, effective combinations could be predicted by correlating sensitivity profiles between drugs. Furthermore, molecular integration with HTS identified biomarkers of sensitivity to WEE1 and MEK inhibition. Incorporating HTS into precision medicine programs is a powerful tool to accelerate the improved identification of effective biomarker-driven therapeutic strategies for treating high-risk pediatric cancers. Significance: Integrating HTS with molecular profiling is a powerful tool for expanding precision medicine to support drug treatment recommendations and broaden the therapeutic options available to high-risk pediatric cancers. /
Publisher: Elsevier BV
Date: 12-2008
DOI: 10.1016/J.IJPHARM.2008.04.040
Abstract: Activation of proximal tubular cells by fibrotic and inflammatory mediators is an important hallmark of chronic kidney disease. We have developed a novel strategy to intervene in renal fibrosis, by means of locally delivered kinase inhibitors. Such compounds will display enhanced activity within tubular cells and reduced unwanted systemic effects. In our approach kinase inhibitors are linked to the renal carrier lysozyme using a platinum-based linker that binds drugs via a coordinative linkage. Many kinase inhibitors contain aromatic nitrogen atoms able to bind to this linker without the need of prior derivatization. The resulting drug-lysozyme conjugates are rapidly filtered in the glomerulus into the tubular lumen and subsequently reabsorbed via the endocytic pathway for clearance of low-molecular weight proteins. An important property of the formed conjugates is their in vivo stability and the sustained drug release profile within target cells. This review summarizes the state-of-the-art of drug targeting to the kidney. Furthermore, we will highlight recent results obtained with kinase inhibitor-lysozyme conjugates targeted to different kinases, i.e. the transforming growth factor (TGF)-beta-receptor kinase, p38 MAPkinase and Rho-associated kinase. Both in vitro and in vivo results demonstrated their efficient tubular uptake and beneficial therapeutic effects, superior to treatment with free kinase inhibitors. These proof-of-concept studies clearly indicate the feasibility of drug targeting for improving the renal specificity of kinase inhibitors.
Publisher: American Association for Cancer Research (AACR)
Date: 15-08-2023
DOI: 10.1158/0008-5472.C.6767498.V2
Abstract: Abstract For one-third of patients with pediatric cancer enrolled in precision medicine programs, molecular profiling does not result in a therapeutic recommendation. To identify potential strategies for treating these high-risk pediatric patients, we performed i in vitro /i screening of 125 patient-derived s les against a library of 126 anticancer drugs. Tumor cell expansion did not influence drug responses, and 82% of the screens on expanded tumor cells were completed while the patients were still under clinical care. High-throughput drug screening (HTS) confirmed known associations between activating genomic alterations in i NTRK /i , i BRAF /i , and i ALK /i and responses to matching targeted drugs. The i in vitro /i results were further validated in patient-derived xenograft models i in vivo /i and were consistent with clinical responses in treated patients. In addition, effective combinations could be predicted by correlating sensitivity profiles between drugs. Furthermore, molecular integration with HTS identified biomarkers of sensitivity to WEE1 and MEK inhibition. Incorporating HTS into precision medicine programs is a powerful tool to accelerate the improved identification of effective biomarker-driven therapeutic strategies for treating high-risk pediatric cancers. Significance: Integrating HTS with molecular profiling is a powerful tool for expanding precision medicine to support drug treatment recommendations and broaden the therapeutic options available to high-risk pediatric cancers. /
Location: Australia
No related grants have been discovered for Emmy Dolman.