36 results on '"Allan EK"'
Search Results
2. Murine monoclonal antibody with anti-e-like specificity: suitability for screening for e-negative cells
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Fraser, RH, primary, Inglis, G, additional, Allan, JC, additional, Murphy, MT, additional, Allan, EK, additional, Mackie, A, additional, and Mitchell, R, additional
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- 1990
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3. A prospective study of real-time panfungal PCR for the early diagnosis of invasive fungal infection in haemato-oncology patients.
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Jordanides, NE, Allan, EK, McLintock, LA, Copland, M, Devaney, M, Stewart, K, Parker, AN, Johnson, PRE, Holyoake, TL, and Jones, BL
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POLYMERASE chain reaction , *DIAGNOSIS , *MYCOSES , *STEM cell transplantation , *BLOOD , *BONE marrow , *HEMATOLOGY - Abstract
Summary:A blinded prospective study was performed to determine whether screening of whole blood using a real-time, panfungal polymerase chain reaction (PCR) technique could predict the development of invasive fungal infection (IFI) in immunocompromised haemato-oncology patients. In all, 78 patients (125 treatment episodes) were screened twice weekly by real-time panfungal PCR using LightCycler™technology. IFI was documented in 19 treatment episodes (five proven, three probable and 11 possible), and in 12, PCR was sequentially positive. PCR positivity occurred in: 4/5 proven; 2/3 probable; 6/11 possible; and 29/106 with no IFI. In 8/12 with IFI and sequentially positive PCR results, PCR positivity occurred before (median 19.5 days) and in 4/12 (median 10.5 days) after the initiation of empirical antifungal therapy. Based on sequential positive results for proven/probable IFI sensitivity, specificity, positive predictive value and negative predictive value were 75, 70, 15 and 98%, respectively. Real-time panfungal PCR is a sensitive tool for the early diagnosis of IFI in immunocompromised haemato-oncology patients. It may be most useful as a screening method in high-risk patients, either to direct early pre-emptive antifungal therapy or to determine when empirical antifungal therapy can be withheld in patients with antibiotic--resistant neutropenic fever. However, these strategies require further assessment in comparative clinical trials.Bone Marrow Transplantation (2005) 35, 389-395. doi:10.1038/sj.bmt.1704768 Published online 10 January 2005 [ABSTRACT FROM AUTHOR]
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- 2005
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4. Evaluation of a panel of human monoclonal antibodies to D and exploration of the synergistic effects of blending IgG1 and IgG3 antibodies on their in vitro biologic function.
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Armstrong-Fisher SS, Carter MCM, Downing I, Fraser RH, Inglis GE, Allan EK, Mackie A, Prowse CV, Templeton JG, Thorpe SJ, Urbaniak SJ, Armstrong-Fisher, S S, Carter, M C, Downing, I, Fraser, R H, Inglis, G E, Allan, E K, Mackie, A, Prowse, C V, and Templeton, J G
- Published
- 1999
5. Estimating and Mapping Ecological Processes Influencing Microbial Community Assembly
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James C Stegen, Xueju eLin, Jim K Fredrickson, and Allan eKonopka
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Microbial biogeography ,Phylogenetic signal ,Ecological niche theory ,Phylogenetic beta-diversity ,Ecological neutral theory ,Hanford Site 300 Area ,Microbiology ,QR1-502 - Abstract
Ecological community assembly is governed by a combination of (i) selection resulting from among-taxa differences in performance; (ii) dispersal resulting from organismal movement; and (iii) ecological drift resulting from stochastic changes in population sizes. The relative importance and nature of these processes can vary across environments. Selection can be homogeneous or variable, and while dispersal is a rate, we conceptualize extreme dispersal rates as two categories; dispersal limitation results from limited exchange of organisms among communities, and homogenizing dispersal results from high levels of organism exchange. To estimate the influence and spatial variation of each process we extend a recently developed statistical framework, use a simulation model to evaluate the accuracy of the extended framework, and use the framework to examine subsurface microbial communities over two geologic formations. For each subsurface community we estimate the degree to which it is influenced by homogeneous selection, variable selection, dispersal limitation, and homogenizing dispersal. Our analyses revealed that the relative influences of these ecological processes vary substantially across communities even within a geologic formation. We further identify environmental and spatial features associated with each ecological process, which allowed mapping of spatial variation in ecological-process-influences. The resulting maps provide a new lens through which ecological systems can be understood; in the subsurface system investigated here they revealed that the influence of variable selection was associated with the rate at which redox conditions change with subsurface depth.
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- 2015
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6. Local Mechanisms for Loud Sound-Enhanced Aminoglycoside Entry into Outer Hair Cells
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Hongzhe eLi, Allan eKachelmeier, David eFurness, and Peter Stephen Steyger
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ototoxicity ,Cellular uptake ,aminoglycoside ,Outer hair cells ,Auditory function ,GTTR ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Loud sound exposure exacerbates aminoglycoside ototoxicity, increasing the risk of permanent hearing loss and degrading the quality of life in affected individuals. We previously reported that loud sound exposure induces temporary threshold shifts (TTS) and enhances uptake of aminoglycosides, like gentamicin, by cochlear outer hair cells (OHCs). Here, we explore mechanisms by which loud sound exposure and TTS could increase aminoglycoside uptake by OHCs that may underlie this form of ototoxic synergy.Mice were exposed to loud sound levels to induce TTS, and received fluorescently-tagged gentamicin (GTTR) for 30 minutes prior to fixation. The degree of TTS was assessed by comparing auditory brainstem responses before and after loud sound exposure. The number of tip links, which gate the GTTR-permeant mechanoelectrical transducer (MET) channels, was determined in OHC bundles, with or without exposure to loud sound, using scanning electron microscopy.We found wide-band noise (WBN) levels that induce TTS also enhance OHC uptake of GTTR compared to OHCs in control cochleae. In cochlear regions with TTS, the increase in OHC uptake of GTTR was significantly greater than in adjacent pillar cells. In control mice, we identified stereociliary tip links at ~50% of potential positions in OHC bundles. However, the number of OHC tip links was significantly reduced in mice that received WBN at levels capable of inducing TTS.These data suggest that GTTR uptake by OHCs during TTS occurs by increased permeation of surviving, mechanically-gated MET channels, and/or non-MET aminoglycoside-permeant channels activated following loud sound exposure. Loss of tip links would hyperpolarize hair cells and potentially increase drug uptake via aminoglycoside-permeant channels expressed by hair cells. The effect of TTS on aminoglycoside-permeant channel kinetics will shed new light on the mechanisms of loud sound-enhanced aminoglycoside uptake, and consequently on ototoxic synergy.
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- 2015
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7. Mouse monoclonal antibodies reacting with M blood group-related antigens
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Fraser, RH, primary, Inglis, G, additional, Mackie, A, additional, Munro, AC, additional, Allan, EK, additional, Mitchell, R, additional, Sonneborn, HH, additional, and Uthemann, H, additional
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- 1985
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8. Effect of mono- and dichromatic light quality on growth rates and photosynthetic performance of Synechococcus sp. PCC 7002
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Hans C Bernstein, Allan eKonopka, Matthew R Melnicki, Eric A Hill, Leo A Kucek, Shuyi eZhang, Gaozhong eShen, Donald A Bryant, and Alexander S Beliaev
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Chlorophyll ,Cyanobacteria ,Photosynthesis ,Chlorophyll Fluorescence ,phycobiliprotein ,turbidostat ,Microbiology ,QR1-502 - Abstract
Synechococcus sp. PCC 7002 was grown to steady state in optically thin turbidostat cultures under conditions for which light quantity and quality was systematically varied by modulating the output of narrow-band LEDs. Cells were provided photons absorbed primarily by chlorophyll (680 nm) or phycocyanin (630 nm) as the organism was subjected to four distinct mono- and dichromatic regimes. During cultivation with dichromatic light, growth rates displayed by Synechococcus sp. PCC 7002 were generally proportional to the total incident irradiance at values < 275 µmol photons m-2 s-1 and were not affected by the ratio of 630:680 nm wavelengths. Notably, under monochromatic light conditions, cultures exhibited similar growth rates only when they were irradiated with 630 nm light; cultures irradiated with only 680 nm light grew at rates that were 60 – 70% of those under other light quality regimes at equivalent irradiances. The functionality of photosystem II and associated processes such as maximum rate of photosynthetic electron transport, rate of cyclic electron flow, and rate of dark respiration generally increased as a function of growth rate. Nonetheless, some of the photophysiological parameters measured here displayed distinct patterns with respect to growth rate of cultures adapted to a single wavelength including phycobiliprotein content, which increased under severely light-limited growth conditions. Additionally, the ratio of photosystem II to photosystem I increased approximately 40% over the range of growth rates, although cells grown with 680 nm light only had the highest ratios. These results suggest the presence of effective mechanisms which allow acclimation of Synechococcus sp. PCC 7002 acclimation to different irradiance conditions.
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- 2014
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9. Application of meta-transcriptomics and –proteomics to analysis of in situ physiological state
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Allan eKonopka and Michael eWilkins
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physiological indicators ,marine habitats ,subsurface sediments ,Microbiology ,QR1-502 - Abstract
Analysis of the growth-limiting factor or environmental stressors affecting microbes in situ is of fundamental importance but analytically difficult. Microbes can reduce in situ limiting nutrient concentrations to sub-micromolar levels, and contaminated ecosystems may contain multiple stressors. The patterns of gene or protein expression by microbes in nature can be used to infer growth limitations, because they are regulated in response to environmental conditions. Experimental studies under controlled conditions in the laboratory provide the physiological underpinnings for developing these physiological indicators. Although regulatory networks may differ among specific microbes, there are some broad principles that can be applied, related to limiting nutrient acquisition, resource allocation, and stress responses. As technologies for transcriptomics and proteomics mature, the capacity to apply these approaches to complex microbial communities will accelerate. In particular, global proteomics reflect expressed catalytic activities. Furthermore, the high mass accuracy of some proteomic approaches allows mapping back to specific microbial strains. For example, at the Rifle IFRC field site in Western Colorado, the physiological status of Fe(III)-reducing populations has been tracked over time. Members of a subsurface clade within the Geobacter predominated during carbon amendment to the subsurface environment. At the functional level, proteomic identifications produced inferences regarding (i) temporal changes in anabolism and catabolism of acetate, (ii) the onset of N2 fixation when N became limiting, and (iii) expression of phosphate transporters during periods of intense growth. The application of these approaches in situ can lead to discovery of novel physiological adaptations.
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- 2012
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10. Targeting BCR-ABL-Independent TKI Resistance in Chronic Myeloid Leukemia by mTOR and Autophagy Inhibition.
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Mitchell R, Hopcroft LEM, Baquero P, Allan EK, Hewit K, James D, Hamilton G, Mukhopadhyay A, O'Prey J, Hair A, Melo JV, Chan E, Ryan KM, Maguer-Satta V, Druker BJ, Clark RE, Mitra S, Herzyk P, Nicolini FE, Salomoni P, Shanks E, Calabretta B, Holyoake TL, and Helgason GV
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- Animals, Cell Line, Tumor, Drug Resistance, Neoplasm genetics, Female, Fusion Proteins, bcr-abl genetics, Humans, Imatinib Mesylate administration & dosage, Imidazoles administration & dosage, Leukemia, Myelogenous, Chronic, BCR-ABL Positive genetics, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, Mice, Molecular Targeted Therapy methods, Pyridazines administration & dosage, Pyrimidines administration & dosage, Quinolines administration & dosage, Xenograft Model Antitumor Assays, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Autophagy drug effects, Drug Resistance, Neoplasm drug effects, Fusion Proteins, bcr-abl antagonists & inhibitors, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Protein Kinase Inhibitors therapeutic use, TOR Serine-Threonine Kinases antagonists & inhibitors
- Abstract
Background: Imatinib and second-generation tyrosine kinase inhibitors (TKIs) nilotinib and dasatinib have statistically significantly improved the life expectancy of chronic myeloid leukemia (CML) patients; however, resistance to TKIs remains a major clinical challenge. Although ponatinib, a third-generation TKI, improves outcomes for patients with BCR-ABL-dependent mechanisms of resistance, including the T315I mutation, a proportion of patients may have or develop BCR-ABL-independent resistance and fail ponatinib treatment. By modeling ponatinib resistance and testing samples from these CML patients, it is hoped that an alternative drug target can be identified and inhibited with a novel compound., Methods: Two CML cell lines with acquired BCR-ABL-independent resistance were generated following culture in ponatinib. RNA sequencing and gene ontology (GO) enrichment were used to detect aberrant transcriptional response in ponatinib-resistant cells. A validated oncogene drug library was used to identify US Food and Drug Administration-approved drugs with activity against TKI-resistant cells. Validation was performed using bone marrow (BM)-derived cells from TKI-resistant patients (n = 4) and a human xenograft mouse model (n = 4-6 mice per group). All statistical tests were two-sided., Results: We show that ponatinib-resistant CML cells can acquire BCR-ABL-independent resistance mediated through alternative activation of mTOR. Following transcriptomic analysis and drug screening, we highlight mTOR inhibition as an alternative therapeutic approach in TKI-resistant CML cells. Additionally, we show that catalytic mTOR inhibitors induce autophagy and demonstrate that genetic or pharmacological inhibition of autophagy sensitizes ponatinib-resistant CML cells to death induced by mTOR inhibition in vitro (% number of colonies of control[SD], NVP-BEZ235 vs NVP-BEZ235+HCQ: 45.0[17.9]% vs 24.0[8.4]%, P = .002) and in vivo (median survival of NVP-BEZ235- vs NVP-BEZ235+HCQ-treated mice: 38.5 days vs 47.0 days, P = .04)., Conclusion: Combined mTOR and autophagy inhibition may provide an attractive approach to target BCR-ABL-independent mechanism of resistance.
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- 2018
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11. ATG7 regulates energy metabolism, differentiation and survival of Philadelphia-chromosome-positive cells.
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Karvela M, Baquero P, Kuntz EM, Mukhopadhyay A, Mitchell R, Allan EK, Chan E, Kranc KR, Calabretta B, Salomoni P, Gottlieb E, Holyoake TL, and Helgason GV
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- Animals, Antigens, CD34 metabolism, Autophagy drug effects, Cell Respiration drug effects, Cell Survival drug effects, Citric Acid Cycle drug effects, Disease Models, Animal, Gene Deletion, Gene Knockdown Techniques, Glycolysis drug effects, Hematopoietic Stem Cells drug effects, Hematopoietic Stem Cells metabolism, Humans, K562 Cells, Metabolic Flux Analysis, Metabolome drug effects, Mice, Mitochondria drug effects, Mitochondria metabolism, Oxidative Phosphorylation drug effects, Protein Kinase Inhibitors pharmacology, Reactive Oxygen Species metabolism, Stem Cells metabolism, Autophagy-Related Protein 7 metabolism, Cell Differentiation drug effects, Energy Metabolism drug effects, Leukemia, Myelogenous, Chronic, BCR-ABL Positive metabolism, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, Philadelphia Chromosome
- Abstract
A major drawback of tyrosine kinase inhibitor (TKI) treatment in chronic myeloid leukemia (CML) is that primitive CML cells are able to survive TKI-mediated BCR-ABL inhibition, leading to disease persistence in patients. Investigation of strategies aiming to inhibit alternative survival pathways in CML is therefore critical. We have previously shown that a nonspecific pharmacological inhibition of autophagy potentiates TKI-induced death in Philadelphia chromosome-positive cells. Here we provide further understanding of how specific and pharmacological autophagy inhibition affects nonmitochondrial and mitochondrial energy metabolism and reactive oxygen species (ROS)-mediated differentiation of CML cells and highlight ATG7 (a critical component of the LC3 conjugation system) as a potential specific therapeutic target. By combining extra- and intracellular steady state metabolite measurements by liquid chromatography-mass spectrometry with metabolic flux assays using labeled glucose and functional assays, we demonstrate that knockdown of ATG7 results in decreased glycolysis and increased flux of labeled carbons through the mitochondrial tricarboxylic acid cycle. This leads to increased oxidative phosphorylation and mitochondrial ROS accumulation. Furthermore, following ROS accumulation, CML cells, including primary CML CD34(+) progenitor cells, differentiate toward the erythroid lineage. Finally, ATG7 knockdown sensitizes CML progenitor cells to TKI-induced death, without affecting survival of normal cells, suggesting that specific inhibitors of ATG7 in combination with TKI would provide a novel therapeutic approach for CML patients exhibiting persistent disease.
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- 2016
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12. The antiproliferative activity of kinase inhibitors in chronic myeloid leukemia cells is mediated by FOXO transcription factors.
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Pellicano F, Scott MT, Helgason GV, Hopcroft LE, Allan EK, Aspinall-O'Dea M, Copland M, Pierce A, Huntly BJ, Whetton AD, and Holyoake TL
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- Animals, Apoptosis drug effects, Cell Cycle Checkpoints drug effects, Cell Line, Tumor, Dasatinib pharmacology, Forkhead Transcription Factors genetics, Forkhead Transcription Factors metabolism, G1 Phase drug effects, Gene Expression Profiling, Humans, K562 Cells, Leukemia, Myelogenous, Chronic, BCR-ABL Positive genetics, Leukemia, Myelogenous, Chronic, BCR-ABL Positive metabolism, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, Mice, Neoplastic Stem Cells drug effects, Neoplastic Stem Cells pathology, Phosphorylation, Signal Transduction, Transfection, Forkhead Transcription Factors biosynthesis, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Protein Kinase Inhibitors pharmacology
- Abstract
Chronic myeloid leukemia (CML) is initiated and maintained by the tyrosine kinase BCR-ABL which activates a number of signal transduction pathways, including PI3K/AKT signaling and consequently inactivates FOXO transcription factors. ABL-specific tyrosine kinase inhibitors (TKIs) induce minimal apoptosis in CML progenitor cells, yet exert potent antiproliferative effects, through as yet poorly understood mechanisms. Here, we demonstrate that in CD34+ CML cells, FOXO1 and 3a are inactivated and relocalized to the cytoplasm by BCR-ABL activity. TKIs caused a decrease in phosphorylation of FOXOs, leading to their relocalization from cytoplasm (inactive) to nucleus (active), where they modulated the expression of key FOXO target genes, such as Cyclin D1, ATM, CDKN1C, and BCL6 and induced G1 arrest. Activation of FOXO1 and 3a and a decreased expression of their target gene Cyclin D1 were also observed after 6 days of in vivo treatment with dasatinib in a CML transgenic mouse model. The over-expression of FOXO3a in CML cells combined with TKIs to reduce proliferation, with similar results seen for inhibitors of PI3K/AKT/mTOR signaling. While stable expression of an active FOXO3a mutant induced a similar level of quiescence to TKIs alone, shRNA-mediated knockdown of FOXO3a drove CML cells into cell cycle and potentiated TKI-induced apoptosis. These data demonstrate that TKI-induced G1 arrest in CML cells is mediated through inhibition of the PI3K/AKT pathway and reactivation of FOXOs. This enhanced understanding of TKI activity and induced progenitor cell quiescence suggests that new therapeutic strategies for CML should focus on manipulation of this signaling network., (© 2014 The Authors. STEM CELLS Published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.)
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- 2014
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13. Autocrine TNF-α production supports CML stem and progenitor cell survival and enhances their proliferation.
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Gallipoli P, Pellicano F, Morrison H, Laidlaw K, Allan EK, Bhatia R, Copland M, Jørgensen HG, and Holyoake TL
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- Apoptosis drug effects, Cell Proliferation drug effects, Cell Survival drug effects, Gene Expression Regulation, Leukemic, Humans, Interleukin-3 antagonists & inhibitors, Interleukin-3 genetics, Interleukin-3 immunology, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Leukemia, Myelogenous, Chronic, BCR-ABL Positive genetics, Leukemia, Myelogenous, Chronic, BCR-ABL Positive metabolism, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, NF-kappa B antagonists & inhibitors, NF-kappa B genetics, NF-kappa B immunology, Neoplastic Stem Cells metabolism, Neoplastic Stem Cells pathology, Primary Cell Culture, Protein Kinase Inhibitors pharmacology, Pyrimidines pharmacology, Receptors, Interleukin-3 antagonists & inhibitors, Receptors, Interleukin-3 genetics, Receptors, Interleukin-3 immunology, Signal Transduction, Tumor Necrosis Factor-alpha genetics, Tumor Necrosis Factor-alpha immunology, Chromones pharmacology, Indoles pharmacology, Neoplastic Stem Cells drug effects, Tumor Necrosis Factor-alpha antagonists & inhibitors
- Abstract
Chronic myeloid leukemia (CML) stem cells are not dependent on BCR-ABL kinase for their survival, suggesting that kinase-independent mechanisms must contribute to their persistence. We observed that CML stem/progenitor cells (SPCs) produce tumor necrosis factor-α (TNF-α) in a kinase-independent fashion and at higher levels relative to their normal counterparts. We therefore investigated the role of TNF-α and found that it supports survival of CML SPCs by promoting nuclear factor κB/p65 pathway activity and expression of the interleukin 3 and granulocyte/macrophage-colony stimulating factor common β-chain receptor. Furthermore, we demonstrate that in CML SPCs, inhibition of autocrine TNF-α signaling via a small-molecule TNF-α inhibitor induces apoptosis. Moreover TNF-α inhibition combined with nilotinib induces significantly more apoptosis relative to either treatment alone and a reduction in the absolute number of primitive quiescent CML stem cells. These results highlight a novel survival mechanism of CML SPCs and suggest a new putative therapeutic target for their eradication.
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- 2013
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14. Investigation into omacetaxine solution stability for in vitro study.
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Marenah L, Allan EK, Mountford JC, Holyoake TL, Jørgensen HG, and Elliott MA
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- Chromatography, High Pressure Liquid, Drug Stability, Homoharringtonine, Hydrogen-Ion Concentration, Solutions chemistry, Spectrophotometry, Ultraviolet, Temperature, Harringtonines chemistry
- Abstract
Omacetaxine is a natural product extract originating from Chinese medicine and finding therapeutic use as a potent myelosuppressive agent in leukemia. When planning in vitro cell biology experiments to assess omacetaxine activity against primary leukemic stem cells, it became apparent that the literature rarely describes the in vitro stability of the molecule, although accessible chromatographic methods have been published. Clearly whole organisms vs their component cells will differ in the way in which they handle xenobiotics, with the latter more dependent on physiochemical parameters such as pH and temperature in the absence of active metabolism or excretion. This could impact on the cells' experience of drug in culture. We therefore report here on examination of a modified, high-performance liquid chromatography (HPLC) method with assessment of degradant production from a 72 h solution stability study, clearly demonstrating that omacetaxine is highly stable in representative cell culture conditions (37 °C, neutral pH) and persists for many days in marked contrast to its short-half life in vivo., (Copyright © 2011 John Wiley & Sons, Ltd.)
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- 2012
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15. Chronic myeloid leukemia stem cells are not dependent on Bcr-Abl kinase activity for their survival.
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Hamilton A, Helgason GV, Schemionek M, Zhang B, Myssina S, Allan EK, Nicolini FE, Müller-Tidow C, Bhatia R, Brunton VG, Koschmieder S, and Holyoake TL
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- Adaptor Proteins, Signal Transducing metabolism, Animals, Antigens, CD34 metabolism, Apoptosis drug effects, Blotting, Western, Cell Line, Tumor, Cell Proliferation drug effects, Cell Survival drug effects, Dasatinib, Dose-Response Relationship, Drug, Flow Cytometry, Fusion Proteins, bcr-abl antagonists & inhibitors, Fusion Proteins, bcr-abl genetics, Gene Expression Regulation, Leukemic, Gene Knockout Techniques, HEK293 Cells, Humans, K562 Cells, Leukemia, Myelogenous, Chronic, BCR-ABL Positive genetics, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, Mice, Mice, Transgenic, Neoplastic Stem Cells pathology, Nuclear Proteins metabolism, Protein Kinase Inhibitors pharmacology, Pyrimidines pharmacology, Reverse Transcriptase Polymerase Chain Reaction, STAT5 Transcription Factor metabolism, Thiazoles pharmacology, Fusion Proteins, bcr-abl metabolism, Leukemia, Myelogenous, Chronic, BCR-ABL Positive metabolism, Neoplastic Stem Cells metabolism
- Abstract
Recent evidence suggests chronic myeloid leukemia (CML) stem cells are insensitive to kinase inhibitors and responsible for minimal residual disease in treated patients. We investigated whether CML stem cells, in a transgenic mouse model of CML-like disease or derived from patients, are dependent on Bcr-Abl. In the transgenic model, after retransplantation, donor-derived CML stem cells in which Bcr-Abl expression had been induced and subsequently shut off were able to persist in vivo and reinitiate leukemia in secondary recipients on Bcr-Abl reexpression. Bcr-Abl knockdown in human CD34(+) CML cells cultured for 12 days in physiologic growth factors achieved partial inhibition of Bcr-Abl and downstream targets p-CrkL and p-STAT5, inhibition of proliferation and colony forming cells, but no reduction of input cells. The addition of dasatinib further inhibited p-CrkL and p-STAT5, yet only reduced input cells by 50%. Complete growth factor withdrawal plus dasatinib further reduced input cells to 10%; however, the surviving fraction was enriched for primitive leukemic cells capable of growth in a long-term culture-initiating cell assay and expansion on removal of dasatinib and addition of growth factors. Together, these data suggest that CML stem cell survival is Bcr-Abl kinase independent and suggest curative approaches in CML must focus on kinase-independent mechanisms of resistance.
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- 2012
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16. Omacetaxine may have a role in chronic myeloid leukaemia eradication through downregulation of Mcl-1 and induction of apoptosis in stem/progenitor cells.
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Allan EK, Holyoake TL, Craig AR, and Jørgensen HG
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- Angiogenesis Inhibitors, Antineoplastic Agents, Phytogenic, Apoptosis, Down-Regulation, Homoharringtonine, Humans, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, Myeloid Cell Leukemia Sequence 1 Protein, Protein Kinase Inhibitors, Tumor Cells, Cultured, Harringtonines pharmacology, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Neoplastic Stem Cells pathology, Proto-Oncogene Proteins c-bcl-2 antagonists & inhibitors
- Abstract
Chronic myeloid leukaemia (CML) is maintained by a rare population of tyrosine kinase inhibitor (TKI)-insensitive malignant stem cells. Our long-term aim is to find a BcrAbl-independent drug that can be combined with a TKI to improve overall disease response in chronic-phase CML. Omacetaxine mepesuccinate, a first in class cetaxine, has been evaluated by clinical trials in TKI-insensitive/resistant CML. Omacetaxine inhibits synthesis of anti-apoptotic proteins of the Bcl-2 family, including (myeloid cell leukaemia) Mcl-1, leading to cell death. Omacetaxine effectively induced apoptosis in primary CML stem cells (CD34(+)38(lo)) by downregulation of Mcl-1 protein. In contrast to our previous findings with TKIs, omacetaxine did not accumulate undivided cells in vitro. Furthermore, the functionality of surviving stem cells following omacetaxine exposure was significantly reduced in a dose-dependant manner, as determined by colony forming cell and the more stringent long-term culture initiating cell colony assays. This stem cell-directed activity was not limited to CML stem cells as both normal and non-CML CD34(+) cells were sensitive to inhibition. Thus, although omacetaxine is not leukaemia stem cell specific, its ability to induce apoptosis of leukaemic stem cells distinguishes it from TKIs and creates the potential for a curative strategy for persistent disease.
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- 2011
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17. Bortezomib induces apoptosis in primitive chronic myeloid leukemia cells including LTC-IC and NOD/SCID repopulating cells.
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Heaney NB, Pellicano F, Zhang B, Crawford L, Chu S, Kazmi SM, Allan EK, Jorgensen HG, Irvine AE, Bhatia R, and Holyoake TL
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- Animals, Antigens, CD34 metabolism, Bortezomib, Cell Line, Tumor, Cell Proliferation drug effects, Dasatinib, Drug Synergism, Fusion Proteins, bcr-abl metabolism, Humans, Mice, Mice, SCID, Mutant Proteins metabolism, Proteasome Inhibitors, Pyrimidines pharmacology, Thiazoles pharmacology, Time Factors, Tumor Stem Cell Assay, Xenograft Model Antitumor Assays, Apoptosis drug effects, Boronic Acids pharmacology, Cell Culture Techniques methods, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, Pyrazines pharmacology
- Abstract
Chronic myeloid leukemia (CML) is treated effectively with tyrosine kinase inhibitors (TKIs); however, 2 key problems remain-the insensitivity of CML stem and progenitor cells to TKIs and the emergence of TKI-resistant BCR-ABL mutations. BCR-ABL activity is associated with increased proteasome activity and proteasome inhibitors (PIs) are cytotoxic against CML cell lines. We demonstrate that bortezomib is antiproliferative and induces apoptosis in chronic phase (CP) CD34+ CML cells at clinically achievable concentrations. We also show that bortezomib targets primitive CML cells, with effects on CD34+38(-), long-term culture-initiating (LTC-IC) and nonobese diabetic/severe combined immunodeficient (NOD/SCID) repopulating cells. Bortezomib is not selective for CML cells and induces apoptosis in normal CD34+38(-) cells. The effects against CML cells are seen when bortezomib is used alone and in combination with dasatinib. Bortezomib causes proteasome but not BCR-ABL inhibition and is also effective in inhibiting proteasome activity and inducing apoptosis in cell lines expressing BCR-ABL mutations, including T315I. By targeting both TKI-insensitive stem and progenitor cells and TKI-resistant BCR-ABL mutations, we believe that bortezomib offers a potential therapeutic option in CML. Because of known toxicities, including myelosuppression, the likely initial clinical application of bortezomib in CML would be in resistant and advanced disease.
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- 2010
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18. Nuclear entrapment of BCR-ABL by combining imatinib mesylate with leptomycin B does not eliminate CD34+ chronic myeloid leukaemia cells.
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Allan EK, Hamilton A, Hatziieremia S, Zhou P, Jørgensen HG, Vigneri P, and Holyoake TL
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- Benzamides, Fatty Acids, Unsaturated administration & dosage, Humans, Imatinib Mesylate, Piperazines administration & dosage, Pyrimidines administration & dosage, Treatment Outcome, Antigens, CD34 metabolism, Antineoplastic Combined Chemotherapy Protocols therapeutic use, Apoptosis drug effects, Cell Nucleus metabolism, Fusion Proteins, bcr-abl metabolism, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Leukemia, Myelogenous, Chronic, BCR-ABL Positive metabolism
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- 2009
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19. BMS-214662 potently induces apoptosis of chronic myeloid leukemia stem and progenitor cells and synergizes with tyrosine kinase inhibitors.
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Copland M, Pellicano F, Richmond L, Allan EK, Hamilton A, Lee FY, Weinmann R, and Holyoake TL
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- Antigens, CD34 metabolism, Antineoplastic Agents pharmacology, Benzamides, Blast Crisis pathology, Caspase 3 metabolism, Cell Death drug effects, Cell Survival drug effects, Dasatinib, Drug Screening Assays, Antitumor, Drug Synergism, Farnesyltranstransferase antagonists & inhibitors, Fusion Proteins, bcr-abl chemistry, Fusion Proteins, bcr-abl metabolism, Humans, Imatinib Mesylate, Leukemia, Myelogenous, Chronic, BCR-ABL Positive enzymology, Mutation genetics, Philadelphia Chromosome, Piperazines pharmacology, Protein Structure, Tertiary, Pyrimidines pharmacology, Thiazoles pharmacology, Apoptosis drug effects, Benzodiazepines pharmacology, Imidazoles pharmacology, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, Neoplastic Stem Cells pathology, Protein Kinase Inhibitors pharmacology
- Abstract
Chronic myeloid leukemia (CML), a hematopoietic stem-cell disorder, cannot be eradicated by conventional chemotherapy or the tyrosine kinase inhibitor imatinib mesylate (IM). To target CML stem/progenitor cells, we investigated BMS-214662, a cytotoxic farnesyltransferase inhibitor, previously reported to kill nonproliferating tumor cells. IM or dasatinib alone reversibly arrested proliferation of CML stem/progenitor cells without inducing apoptosis. In contrast, BMS-214662, alone or in combination with IM or dasatinib, potently induced apoptosis of both proliferating and quiescent CML stem/progenitor cells with less than 1% recovery of Philadelphia-positive long-term culture-initiating cells. Normal stem/progenitor cells were relatively spared by BMS-214662, suggesting selectivity for leukemic stem/progenitor cells. The ability to induce selective apoptosis of leukemic stem/progenitor cells was unique to BMS-214662 and not seen with a structurally similar agent BMS-225975. BMS-214662 was cytotoxic against CML blast crisis stem/progenitor cells, particularly in combination with a tyrosine kinase inhibitor and equally effective in cell lines harboring wild-type vs mutant BCR-ABL, including the T315I mutation. This is the first report of an agent with activity in resistant and blast crisis CML that selectively kills CML stem/progenitor cells through apoptosis and offers potential for eradication of chronic phase CML.
- Published
- 2008
- Full Text
- View/download PDF
20. Nilotinib exerts equipotent antiproliferative effects to imatinib and does not induce apoptosis in CD34+ CML cells.
- Author
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Jørgensen HG, Allan EK, Jordanides NE, Mountford JC, and Holyoake TL
- Subjects
- Benzamides, Dose-Response Relationship, Drug, Drug Resistance, Neoplasm drug effects, Drug Synergism, Fusion Proteins, bcr-abl metabolism, Humans, Imatinib Mesylate, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Piperazines agonists, Protein Kinase Inhibitors agonists, Pyrimidines agonists, Time Factors, Antigens, CD34, Apoptosis drug effects, Cell Proliferation drug effects, Fusion Proteins, bcr-abl antagonists & inhibitors, Leukemia, Myelogenous, Chronic, BCR-ABL Positive enzymology, Neoplastic Stem Cells enzymology, Piperazines pharmacology, Protein Kinase Inhibitors pharmacology, Pyrimidines pharmacology, Tumor Stem Cell Assay
- Abstract
Chronic myeloid leukemia (CML) stem and progenitor cells overexpress BcrAbl and are insensitive to imatinib mesylate (IM). We therefore investigated whether these cells were efficiently targeted by nilotinib. In K562, the inhibitory concentration (IC50) of nilotinib was 30 nM versus 600 nM for IM, consistent with its reported 20-fold-higher potency. However, in primary CD34(+) CML cells, nilotinib and IM were equipotent for inhibition of BcrAbl activity, producing equivalent but incomplete reduction in CrkL phosphorylation at 5 microM. CML CD34(+) cells were still able to expand over 72 hours with 5 microM of either drug, although there was a concentration-dependent restriction of amplification. As for IM, the most primitive cells (CFSE(max)) persisted and accumulated over 72 hours with nilotinib and remained caspase-3 negative. Furthermore, nilotinib with IM led to further accumulation of this population, suggesting at least additive antiproliferative effects. These results confirmed that, like IM, the predominant effect of nilotinib is antiproliferative rather than proapoptotic.
- Published
- 2007
- Full Text
- View/download PDF
21. Human neutrophil elastase is not a target for therapy in chronic myeloid leukaemia.
- Author
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Allan EK, Holyoake TL, and Jørgensen HG
- Subjects
- Humans, Drug Design, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Leukemia, Myelogenous, Chronic, BCR-ABL Positive metabolism, Leukocyte Elastase metabolism
- Published
- 2006
- Full Text
- View/download PDF
22. Dasatinib (BMS-354825) targets an earlier progenitor population than imatinib in primary CML but does not eliminate the quiescent fraction.
- Author
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Copland M, Hamilton A, Elrick LJ, Baird JW, Allan EK, Jordanides N, Barow M, Mountford JC, and Holyoake TL
- Subjects
- Adaptor Proteins, Signal Transducing metabolism, Antigens, CD34, Benzamides, Dasatinib, Drug Resistance, Neoplasm, Fusion Proteins, bcr-abl genetics, Gene Dosage, HL-60 Cells, Humans, Imatinib Mesylate, K562 Cells, Leukemia, Myelogenous, Chronic, BCR-ABL Positive genetics, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, Nuclear Proteins metabolism, Phosphorylation, RNA, Neoplasm analysis, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Neoplastic Stem Cells drug effects, Piperazines pharmacology, Pyrimidines pharmacology, Thiazoles pharmacology
- Abstract
Dasatinib (BMS-354825), a novel dual SRC/BCR-ABL kinase inhibitor, exhibits greater potency than imatinib mesylate (IM) and inhibits the majority of kinase mutations in IM-resistant chronic myeloid leukemia (CML). We have previously demonstrated that IM reversibly blocks proliferation but does not induce apoptosis of primitive CML cells. Here, we have attempted to overcome this resistance with dasatinib. Primitive IM-resistant CML cells showed only single-copy BCR-ABL but expressed significantly higher BCR-ABL transcript levels and BCR-ABL protein compared with more mature CML cells (P = .031). In addition, CrKL phosphorylation was higher in the primitive CD34(+)CD38(-) than in the total CD34(+) population (P = .002). In total CD34(+) CML cells, IM inhibited phosphorylation of CrKL at 16 but not 72 hours, consistent with enrichment of an IM-resistant primitive population. CD34(+)CD38(-) CML cells proved resistant to IM-induced inhibition of CrKL phosphorylation and apoptosis, whereas dasatinib led to significant inhibition of CrKL phosphorylation. Kinase domain mutations were not detectable in either IM or dasatinib-resistant primitive CML cells. These data confirm that dasatinib is more effective than IM within the CML stem cell compartment; however, the most primitive quiescent CML cells appear to be inherently resistant to both drugs.
- Published
- 2006
- Full Text
- View/download PDF
23. Intermittent exposure of primitive quiescent chronic myeloid leukemia cells to granulocyte-colony stimulating factor in vitro promotes their elimination by imatinib mesylate.
- Author
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Jørgensen HG, Copland M, Allan EK, Jiang X, Eaves A, Eaves C, and Holyoake TL
- Subjects
- Benzamides, Blast Crisis, Bone Marrow Cells metabolism, Culture Media, Serum-Free pharmacology, Drug Combinations, Fusion Proteins, bcr-abl metabolism, Humans, Imatinib Mesylate, In Vitro Techniques, Leukemia, Myelogenous, Chronic, BCR-ABL Positive metabolism, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, Protein-Tyrosine Kinases antagonists & inhibitors, RNA, Messenger genetics, RNA, Messenger metabolism, Receptors, Granulocyte Colony-Stimulating Factor genetics, Receptors, Granulocyte Colony-Stimulating Factor metabolism, Tumor Cells, Cultured, Antineoplastic Agents therapeutic use, Bone Marrow Cells drug effects, Granulocyte Colony-Stimulating Factor administration & dosage, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Piperazines therapeutic use, Pyrimidines therapeutic use
- Abstract
Purpose: Primitive quiescent chronic myeloid leukemia (CML) cells are biologically resistant to imatinib mesylate, an inhibitor of the p210(BCR-ABL) kinase. The present study was designed to investigate whether either continuous or intermittent exposure of these cells to granulocyte-colony stimulating factor (G-CSF) in vitro can overcome this limitation to the effectiveness of imatinib mesylate therapy., Experimental Design: CD34(+) leukemic cells were isolated from six newly diagnosed chronic phase CML patients and cultured for 12 days in serum-free medium with or without G-CSF and/or imatinib mesylate present either continuously or intermittently (three cycles of G-CSF for 0, 1, or 4 days +/- imatinib mesylate for 0, 3, or 4 days). Every 4 days, the number of residual undivided viable cells and the total number of viable cells present were measured., Results: Intermittent but not continuous exposure to G-CSF significantly accelerated the disappearance in vitro of initially quiescent CD34(+) CML cells. This resulted in 3- and 5-fold fewer of these cells remaining after 8 and 12 days, respectively, relative to continuous imatinib mesylate alone (P < 0.04). Cultures containing imatinib mesylate and intermittently added G-CSF also showed the greatest reduction in the total number of cells present after 12 days (5-fold more than imatinib mesylate alone)., Conclusion: Intermittent exposure to G-CSF can enhance the effect of imatinib mesylate on CML cells by specifically targeting the primitive quiescent leukemic elements. A protocol for treating chronic-phase CML patients with imatinib mesylate that incorporates intermittent G-CSF exposure may offer a novel strategy for obtaining improved responses in vivo.
- Published
- 2006
- Full Text
- View/download PDF
24. Enhanced CML stem cell elimination in vitro by bryostatin priming with imatinib mesylate.
- Author
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Jørgensen HG, Allan EK, Mountford JC, Richmond L, Harrison S, Elliott MA, and Holyoake TL
- Subjects
- Antigens, CD34 metabolism, Benzamides, Bryostatins, Drug Antagonism, G1 Phase drug effects, Hematopoietic Stem Cells pathology, Humans, Imatinib Mesylate, K562 Cells, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, Macrolides antagonists & inhibitors, Piperazines antagonists & inhibitors, Protein Kinase C antagonists & inhibitors, Protein Kinase C metabolism, Pyrimidines antagonists & inhibitors, Resting Phase, Cell Cycle drug effects, Antineoplastic Agents pharmacology, Apoptosis drug effects, Hematopoietic Stem Cells metabolism, Leukemia, Myelogenous, Chronic, BCR-ABL Positive metabolism, Macrolides pharmacology, Piperazines pharmacology, Pyrimidines pharmacology
- Abstract
Objective: In chronic myeloid leukemia (CML), imatinib mesylate (IM; Gleevec, Glivec) induces a G0/G1 cell-cycle block in total CD34(+) cells without causing significant apoptosis. Bryostatin-1 (bryo), a protein kinase C (PKC) modulator, was investigated for its ability to increase IM-mediated apoptosis either through induction of cycling of G0/G1 Ph(+) cells or antagonism of the IM-induced cell-cycle block., Methods: The Ph(+) K562 cell line and primary CD34(+) CML cells were studied for cell-cycle progression (PI staining), proliferation ((3)H thymidine uptake), and survival (dye exclusion)., Results: Following 48 hours exposure to IM, on average more than 80% of surviving K562 cells were in G0/G1 as compared to approximately 50% for untreated control cultures (p < 0.001). After accounting for IM-induced cell kill, the absolute number of viable G0/G1 cells was significantly increased, confirming its anti-proliferative effect. However, pretreatment for 24 hours with bryo both increased K562 total cell kill and normalized the percentage of cells recovered in G0/G1, thus reducing their absolute number. For primary CML CD34(+) cells, pretreatment with bryo prior to IM significantly enhanced cell death of both total and, critically, G0/G1 populations., Conclusion: These results suggest that carefully scheduled drug combinations that include an agent to antagonize the anti-proliferative effect of IM may prove more efficacious within the Ph(+) stem cell compartment than IM monotherapy.
- Published
- 2005
- Full Text
- View/download PDF
25. Lonafarnib reduces the resistance of primitive quiescent CML cells to imatinib mesylate in vitro.
- Author
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Jørgensen HG, Allan EK, Graham SM, Godden JL, Richmond L, Elliott MA, Mountford JC, Eaves CJ, and Holyoake TL
- Subjects
- Antigens, CD34 drug effects, Benzamides, Benzoquinones, Cell Line, Tumor, Chromones pharmacology, Cytarabine pharmacology, Dose-Response Relationship, Drug, Drug Resistance, Neoplasm drug effects, Drug Screening Assays, Antitumor, Drug Synergism, Female, Humans, Imatinib Mesylate, Lactams, Macrocyclic, Male, Morpholines pharmacology, Rifabutin analogs & derivatives, Rifabutin pharmacology, Antineoplastic Combined Chemotherapy Protocols pharmacology, Cell Proliferation drug effects, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Piperazines pharmacology, Piperidines pharmacology, Pyridines pharmacology, Pyrimidines pharmacology
- Abstract
Recent studies indicate that a rare population of primitive quiescent BCR-ABL(+) cells are innately insensitive to imatinib mesylate (IM) and persist after IM therapy of patients with chronic myeloid leukemia (CML). New approaches to the eradication of these cells are therefore likely to be crucial to the development of curative therapies for CML. We have now found that Ara-C, LY294002 (a PI-3 (phosphatidylinositol-3' kinase) kinase inhibitor), 17AAG (a heat-shock protein (HSP)-90 antagonist) and lonafarnib (a farnesyltransfease inhibitor) all enhance the toxicity of IM on K562 cells and on the total CD34(+) leukemic cell population from chronic phase CML patients. However, for quiescent CD34(+) leukemic cells, this was achieved only by concomitant exposure of the cells to lonafarnib. Ara-C or LY294002 alone blocked the proliferation of these cells but did not kill them, and Ara-C, LY294002 or 17AAG in combination with IM enhanced the cytostatic effect of IM but did not prevent the subsequent regrowth of the surviving leukemic cells. These studies demonstrate the importance of in vitro testing of novel agents on the subset of primary leukemic cells most likely to determine long-term treatment outcomes in vivo.
- Published
- 2005
- Full Text
- View/download PDF
26. Poor performance of galactomannan and mannan sandwich enzyme-linked immunosorbent assays in the diagnosis of invasive fungal infection.
- Author
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Allan EK, Jordanides NE, McLintock LA, Copland M, Devaney M, Stewart K, Parker AN, Johnson PR, Holyoake TL, and Jones BL
- Subjects
- Adolescent, Adult, Aged, Enzyme-Linked Immunosorbent Assay methods, Galactose analogs & derivatives, Humans, Mannans analysis, Middle Aged, Prospective Studies, Sensitivity and Specificity, Single-Blind Method, Aspergillosis diagnosis, Candidiasis diagnosis
- Published
- 2005
- Full Text
- View/download PDF
27. Successful haemopoietic stem cell transplantation does not correct mannan-binding lectin deficiency.
- Author
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Kilpatrick DC, Stewart K, Allan EK, McLintock LA, Holyoake TL, and Turner ML
- Subjects
- Adult, Hematologic Neoplasms complications, Humans, Immunologic Deficiency Syndromes complications, Infections etiology, Male, Mannose-Binding Lectin blood, Middle Aged, Remission Induction, Tissue Donors, Treatment Outcome, Hematologic Neoplasms therapy, Hematopoietic Stem Cell Transplantation, Immunologic Deficiency Syndromes therapy, Mannose-Binding Lectin deficiency
- Abstract
It has been reported that in allogeneic stem cell transplantation, the mannan-binding lectin (MBL) status of the donor has prognostic value for the recipient. Two MBL-deficient patients, with coexisting haematological malignancy, were identified who were treated with bone marrow from donors with normal MBL concentrations. Although both patients engrafted successfully and remain in complete remission, neither seroconverted to the MBL sufficiency status of his donor over a follow-up period exceeding 2 years. This does not support the concept of MBL replacement by stem cell therapy, and does not provide an explanation for high MBL concentrations in stem cell donors protecting recipients from post transplant infections.
- Published
- 2005
- Full Text
- View/download PDF
28. The use of a risk group stratification in the management of invasive fungal infection: a prospective validation.
- Author
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McLintock LA, Jordanides NE, Allan EK, Copland M, Stewart K, Parker A, Devaney M, Holyoake TL, and Jones BL
- Subjects
- Hematologic Diseases therapy, Humans, Risk Assessment, Risk Factors, Hematologic Diseases microbiology, Immunocompromised Host, Mycoses diagnosis, Opportunistic Infections diagnosis
- Published
- 2004
- Full Text
- View/download PDF
29. Fluorescence in situ hybridization for BCR-ABL.
- Author
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Drummond MW, Allan EK, Pearce A, and Holyoake TL
- Subjects
- Bone Marrow Cells pathology, DNA Probes, Humans, Leukemia, Myelogenous, Chronic, BCR-ABL Positive blood, Leukemia, Myelogenous, Chronic, BCR-ABL Positive diagnosis, Tumor Cells, Cultured, Fusion Proteins, bcr-abl genetics, In Situ Hybridization, Fluorescence methods, Leukemia, Myelogenous, Chronic, BCR-ABL Positive genetics
- Published
- 2004
- Full Text
- View/download PDF
30. No strong relationship between mannan binding lectin or plasma ficolins and chemotherapy-related infections.
- Author
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Kilpatrick DC, McLintock LA, Allan EK, Copland M, Fujita T, Jordanides NE, Koch C, Matsushita M, Shiraki H, Stewart K, Tsujimura M, Turner ML, Franklin IM, and Holyoake TL
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Antineoplastic Agents therapeutic use, Disease Susceptibility, Female, Hematologic Neoplasms drug therapy, Hematologic Neoplasms immunology, Humans, Immunocompromised Host immunology, Male, Middle Aged, Neutropenia chemically induced, Neutropenia complications, Neutropenia immunology, Opportunistic Infections complications, Severity of Illness Index, Ficolins, Antineoplastic Agents adverse effects, Carrier Proteins blood, Lectins, Mannose-Binding Lectin blood, Opportunistic Infections blood
- Abstract
Chemotherapy causes neutropenia and an increased susceptibility to infection. Recent reports indicate that mannan-binding lectin (MBL) insufficiency is associated with an increased duration of febrile neutropenia and incidence of serious infections following chemotherapy for haematological malignancies. We aimed to confirm or refute this finding and to extend the investigation to the plasma ficolins, P35 (L-ficolin) and the Hakata antigen (H-ficolin). MBL, L-ficolin and H-ficolin were measured in 128 patients with haematological malignancies treated by chemotherapy alone or combined with bone marrow transplantation. Protein concentrations were related to clinical data retrieved from medical records. MBL concentrations were elevated compared with healthy controls in patients who received chemotherapy, while L-ficolin concentrations were decreased and H-ficolin levels were unchanged. There was no correlation between MBL, L-ficolin or H-ficolin concentration and febrile neutropenia expressed as the proportion of neutropenic periods in which patients experienced fever, and there was no relation between abnormally low (deficiency) levels of MBL, L-ficolin or H-ficolin and febrile neutropenia so expressed. Patients with MBL < or =0.1 microg/ml had significantly more major infections than no infections within the follow-up period (P<0.05), but overall most patients had signs or symptoms of minor infections irrespective of MBL concentration. Neither L-ficolin nor H-ficolin deficiencies were associated with infections individually, in combination or in combination with MBL deficiency. MBL, L-ficolin and H-ficolin, independently or in combination, did not have a major influence on susceptibility to infection in these patients rendered neutropenic by chemotherapy. These results cast doubt on the potential value of MBL replacement therapy in this clinical context.
- Published
- 2003
- Full Text
- View/download PDF
31. Stage-specific alterations in serum levels of G-CSF in chronic myeloid leukaemia.
- Author
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Jørgensen HG, Allan EK, Jiang X, Liakopoulou E, Richmond L, Eaves CJ, Eaves AC, and Holyoake TL
- Subjects
- Case-Control Studies, Disease Progression, Humans, Leukemia, Myelogenous, Chronic, BCR-ABL Positive blood, Granulocyte Colony-Stimulating Factor blood, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology
- Published
- 2003
- Full Text
- View/download PDF
32. Alpha1-acid glycoprotein expressed in the plasma of chronic myeloid leukemia patients does not mediate significant in vitro resistance to STI571.
- Author
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Jørgensen HG, Elliott MA, Allan EK, Carr CE, Holyoake TL, and Smith KD
- Subjects
- Antineoplastic Agents metabolism, Antineoplastic Agents therapeutic use, Benzamides, Blotting, Western, Drug Resistance, Neoplasm, Enzyme Inhibitors metabolism, Enzyme Inhibitors therapeutic use, Fusion Proteins, bcr-abl antagonists & inhibitors, Humans, Imatinib Mesylate, Leukemia, Myelogenous, Chronic, BCR-ABL Positive drug therapy, Neoplasm Proteins antagonists & inhibitors, Neoplasm Proteins blood, Orosomucoid analysis, Piperazines metabolism, Piperazines therapeutic use, Pyrimidines metabolism, Pyrimidines therapeutic use, Antineoplastic Agents pharmacology, Enzyme Inhibitors pharmacology, Leukemia, Myelogenous, Chronic, BCR-ABL Positive blood, Neoplasm Proteins physiology, Orosomucoid physiology, Piperazines pharmacology, Pyrimidines pharmacology
- Abstract
Despite the efficacy of STI571 (Glivec, Novartis, Basle, Switzerland) in treating chronic myeloid leukemia (CML), drug resistance has already been noted both in vitro and in vivo. As plasma proteins, including alpha-1-acid glycoprotein (AGP), may reduce drug efficacy through binding, AGP was investigated for its ability to interact with STI571. At all stages of CML, AGP plasma level was significantly higher than in normal controls (P <.05). The glycoprotein was purified from normal plasma and individual chronic myeloid leukemia (CML) patients' plasma by low-pressure chromatography. The influence of alpha1-acid glycoprotein (AGP), in the presence of STI571, on the proliferation of Philadelphia chromosome-positive (Ph+) cells was examined. Normal AGP, even at supraphysiological concentrations, did not block the effect of STI571 on K562-cell proliferation in vitro. Moreover, CML-derived AGP failed to block the effect of STI571 on Ph+ cells in vitro. Thus, these in vitro findings suggest that AGP will not abrogate the antileukemic activity of STI571.
- Published
- 2002
- Full Text
- View/download PDF
33. Production and immunochemical characterization of mouse monoclonal antibodies to human Lewis blood group structures.
- Author
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Fraser RH, Allan EK, Inglis G, Munro AC, Mackie A, and Mitchell R
- Subjects
- Animals, Antibodies, Monoclonal biosynthesis, Antibody Specificity, Carbohydrate Conformation, Carbohydrates immunology, Epitopes immunology, Erythrocytes immunology, Glycolipids immunology, Humans, Immunoglobulin M biosynthesis, Immunoglobulin M immunology, Mice, Mice, Inbred BALB C immunology, Mice, Inbred NZB immunology, Antibodies, Monoclonal immunology, Lewis Blood Group Antigens immunology
- Abstract
Two mouse monoclonal antibodies with specificity for the Lea blood group determinant of human red cells have been produced by immunising mice with soluble Lewis substance. Both antibodies were of the IgM class and agglutinated only trypsinised or papainised Lea-positive red cells. The precise antigenic conformations recognised by these antibodies have been defined by inhibition studies with monosaccharides, disaccharides and synthetic blood group oligosaccharides. These studies have suggested that the alpha-side of a 1-substituted D-galactosyl residue is a central part of the determinants recognised by the antibodies. Preliminary studies have shown these antibodies to be superior to many of the presently available human and animal polyclonal reagents for routine Lea typing of red cells.
- Published
- 1984
34. Serological characterisation of a mouse monoclonal anti-P-like antibody.
- Author
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Inglis G, Fraser RH, Mitchell AA, Mackie A, Allan EK, and Mitchell R
- Subjects
- Animals, Epitopes immunology, Fetal Blood immunology, Hemagglutination, Humans, Immunoglobulin M immunology, Mice, Trihexosylceramides blood, Trihexosylceramides immunology, Antibodies, Monoclonal immunology, Blood Group Antigens immunology, P Blood-Group System immunology
- Abstract
An IgM mouse monoclonal antibody, LM 147/328, raised against an Escherichia coli immunogen, was found to possess anti-P-like specificity. It is proposed that this antibody recognises an epitope on a Gal beta 1-3GalNAc disaccharide structure (GalNAc = N-acetyl-D-galactosamine). The haemagglutinating activity of this antibody was consistently strong with adult erythrocytes, but gave significantly weak reactions with about 7% of cord erythrocyte samples.
- Published
- 1987
- Full Text
- View/download PDF
35. The potentiation of "incomplete" mouse monoclonal anti-Lea agglutination with colloids.
- Author
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Inglis G, Fraser RH, Durosinmi MA, Allan EK, Mackie A, and Mitchell R
- Subjects
- Binding Sites, Antibody, Colloids, Erythrocyte Count, Erythrocytes, Humans, Antibodies, Monoclonal immunology, Dextrans pharmacology, Hemagglutination drug effects, Isoantibodies immunology, Lewis Blood Group Antigens, Serum Albumin pharmacology
- Abstract
Mouse monoclonal anti-Lea produced in this center was found to agglutinate only Le(a+) red cells which had been modified with proteases. In order to provide a stable medium in which the monoclonal anti-Lea would directly agglutinate unmodified red cells, the potentiating effect of a variety of colloids was assessed. Satisfactory results were obtained when 10 percent (wt/vol) dextran and 2 percent (wt/vol) bovine serum albumin were added to the culture supernatant containing anti-Lea. It is suggested that direct hemagglutination mediated by these colloids resulted from a combination of increased antibody uptake by Le(a+) red cells and change in the shape of these red cells induced by dextran.
- Published
- 1985
- Full Text
- View/download PDF
36. POST-MEASLES COMPLICATIONS: A CASE STUDY FROM NAZARETH.
- Author
-
ALLAN EK
- Subjects
- Child, Humans, Israel, Bronchopneumonia, Measles, Otitis Media
- Published
- 1964
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