124 results on '"Daniela M. Zisterer"'
Search Results
52. Inhibition of γ-secretase activity synergistically enhances tumour necrosis factor-related apoptosis-inducing ligand induced apoptosis in T-cell acute lymphoblastic leukemia cells via upregulation of death receptor 5
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Daniela M. Zisterer, Seema M. Nathwani, and Lisa M. Greene
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0301 basic medicine ,Cancer Research ,Programmed cell death ,Necrosis ,T cell ,Articles ,Pharmacology ,Cell cycle ,Biology ,Inhibitor of apoptosis ,03 medical and health sciences ,030104 developmental biology ,0302 clinical medicine ,medicine.anatomical_structure ,Oncology ,Downregulation and upregulation ,Apoptosis ,030220 oncology & carcinogenesis ,medicine ,medicine.symptom ,Receptor - Abstract
T-cell acute lymphoblastic leukemia (T-ALL) is a rare and aggressive hematopoietic malignancy prone to relapse and drug resistance. Half of all T-ALL patients exhibit mutations in Notch1, which leads to aberrant Notch1 associated signaling cascades. Notch1 activation is mediated by the γ-secretase cleavage of the Notch1 receptor into the active intracellular domain of Notch1 (NCID). Clinical trials of γ-secretase small molecule inhibitors (GSIs) as single agents for the treatment of T-ALL have been unsuccessful. The present study demonstrated, using immunofluorescence and western blotting, that blocking γ-secretase activity in T-ALL cells with N-[(3,5-difluorophenyl) acetyl]-L-alanyl-2-phenyl] glycine-1,1-dimethylethyl ester (DAPT) downregulated NCID and upregulated the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptor 5 (DR5). Upregulation of DR5 restored the sensitivity of T-ALL cells to TRAIL. Combination index revealed that the combined treatment of DAPT and TRAIL synergistically enhanced apoptosis compared with treatment with either drug alone. TRAIL combined with the clinically evaluated γ-secretase inhibitor 3-[(1r, 4s)-4-(4-chlorophenylsulfonyl)-4-(2, 5-difluorophenyl) cyclohexyl] propanoic acid (MK-0752) also significantly enhanced TRAIL-induced cell death compared with either drug alone. DAPT/TRAIL apoptotic synergy was dependent on the extrinsic apoptotic pathway and was associated with a decrease in BH3 interacting-domain death agonist and x-linked inhibitor of apoptosis. In conclusion, γ-secretase inhibition represents a potential therapeutic strategy to overcome TRAIL resistance for the treatment of T-ALL.
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- 2015
53. Lead identification of β-lactam and related imine inhibitors of the molecular chaperone heat shock protein 90
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David Lloyd, Niamh M. O’Boyle, D. Clive Williams, Mary J. Meegan, Trevor T. Price, Daniela M. Zisterer, Andrew J. S. Knox, O'Boyle, Niamh M, Knox, Andrew JS, Price, Trevor T, Williams, D Clive, Zisterer, Daniela M, Lloyd, David G, and Meegan, Mary J
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Models, Molecular ,β-lactam ,Clinical Biochemistry ,Imine ,Chemical Actions and Uses ,Pharmaceutical Science ,Structural diversity ,Antineoplastic Agents ,Breast Neoplasms ,Hsp90 ,beta-Lactams ,Biochemistry ,Structure-Activity Relationship ,chemistry.chemical_compound ,Heterocyclic Compounds ,Heat shock protein ,Drug Discovery ,Humans ,Structure–activity relationship ,HSP90 Heat-Shock Proteins ,Heat shock protein 90 ,Organic Chemicals ,Molecular Biology ,anti-cancer ,azetidinone ,biology ,structure-activity relationship ,Organic Chemistry ,Medicinal Chemistry and Pharmaceutics ,chemistry ,heat shock protein 90 (Hsp90) ,biology.protein ,Lactam ,Molecular Medicine ,Female ,Imines ,imine - Abstract
Heat shock protein 90 is an emerging target for oncology therapeutics. Inhibitors of this molecular chaperone, which is responsible for the maintenance of a number of oncogenic proteins, have shown promise in clinical trials and represent a new and exciting area in the treatment of cancer. Heat shock protein 90 inhibitors have huge structural diversity, and here we present the lead identification of novel inhibitors based on β-lactam and imine templates. β-Lactam 5 and imines 12 and 18 exhibit binding to heat shock protein 90-α with IC50 values of 5.6 μM, 14.5 μM, and 22.1 μM, respectively. The binding affinity displayed by these compounds positions them as lead compounds for the design of future inhibitors of heat shock protein 90 based on the β-lactam and imine templates. Refereed/Peer-reviewed
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- 2011
54. Synthesis, biochemical and molecular modelling studies of antiproliferative azetidinones causing microtubule disruption and mitotic catastrophe
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Mary J. Meegan, David Lloyd, Miriam Carr, Daniela M. Zisterer, Lisa M. Greene, Niall O. Keely, Niamh M. O’Boyle, Andrew J. S. Knox, Thomas McCabe, O'Boyle, Niamh M, Carr, Miriam, Greene, Lisa M, Keely, Niall O, Knox, Andrew JS, McCabe, Thomas, Lloyd, David George, Zisterer, Daniela M, and Meegan, Mary J
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Models, Molecular ,Magnetic Resonance Spectroscopy ,Spectrophotometry, Infrared ,β-lactam ,Cell ,Chemical Actions and Uses ,Mitosis ,Crystallography, X-Ray ,Biochemistry ,Microtubules ,Inhibitory Concentration 50 ,chemistry.chemical_compound ,Multinucleate ,Heterocyclic Compounds ,Microtubule ,Cell Line, Tumor ,Enzymes and Coenzymes ,Drug Discovery ,medicine ,Humans ,Organic Chemicals ,mitotic catastrophe ,Mitotic catastrophe ,Cell Proliferation ,Pharmacology ,Combretastatin ,azetidinone ,Microscopy, Confocal ,biology ,Chemistry ,Organic Chemistry ,General Medicine ,Cell cycle ,Flow Cytometry ,Cell biology ,Medicinal Chemistry and Pharmaceutics ,medicine.anatomical_structure ,Tubulin ,tubulin ,Microscopy, Fluorescence ,Cell culture ,biology.protein ,Azetidines ,Antiproliferative ,combretastatin - Abstract
The structure-activity relationships of antiproliferative β-lactams, focusing on modifications at the 4- position of the β-lactam ring, is described. Synthesis of this series of compounds was achieved utilizing the Staudinger and Reformatsky reactions. The antiproliferative activity was assessed in MCF-7 cells, where the 4-(4-ethoxy)phenyl substituted compound 26 displayed the most potent activity with an IC50 value of 0.22 μM. The mechanism of action was demonstrated to be by inhibition of tubulin polymerisation. Cell exposure to combretastatin A-4 and 26 led to arrest of MCF-7 cells in the G2/M phase of the cell cycle and induction of apoptosis. Additionally, mitotic catastrophe for combretastatin A-4 and for 26 was demonstrated in breast cancer cells for the first time, as evidenced by the formation of giant, multinucleated cells. Refereed/Peer-reviewed
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- 2011
55. Synthesis, evaluation and structural studies of antiproliferative tubulin-targeting azetidin-2-ones
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Mary J. Meegan, David Lloyd, Thomas McCabe, Lisa M. Greene, Jean-Baptiste Fichet, Niamh M. O’Boyle, Daniela M. Zisterer, Orla Bergin, O'Boyle, Niamh M, Greene, Lisa M, Bergin, Orla, Fichet, Jean-Baptiste, McCabe, Thomas, Lloyd, David G, Zisterer, Daniela M, and Meegan, Mary J
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Models, Molecular ,structure-activity ,Double bond ,β-lactam ,Stereochemistry ,Clinical Biochemistry ,Pharmaceutical Science ,Breast Neoplasms ,Cell Growth Processes ,Crystallography, X-Ray ,beta-Lactams ,Biochemistry ,colchicine ,Mice ,Structure-Activity Relationship ,chemistry.chemical_compound ,Pregnancy ,Tubulin ,antiproliferative ,Cell Line, Tumor ,Drug Discovery ,Animals ,Humans ,Structure–activity relationship ,Staudinger reaction ,Reformatsky reaction ,combretastatin A-4 analogues ,Cytotoxicity ,Molecular Biology ,Combretastatin ,chemistry.chemical_classification ,azetidinone ,biology ,Organic Chemistry ,Epithelial Cells ,Medicinal Chemistry and Pharmaceutics ,tubulin ,chemistry ,Cell culture ,axetidinone ,biology.protein ,Azetidines ,cytotoxicity ,Molecular Medicine ,Female - Abstract
A series of azetidin-2-ones substituted at positions 1, 3 and 4 of the azetidinone ring scaffold were synthesised and evaluated for antiproliferative, cytotoxic and tubulin-binding activity. In these compounds, the cis double bond of the vascular targeting agent combretastatin A-4 is replaced with the azetidinone ring in order to enhance the antiproliferative effects displayed by combretastatin A-4 and prevent the cis/ trans isomerisation that is associated with inactivation of combretastatin A-4. The series of azetidinones was synthetically accessible via the Staudinger and Reformatsky reactions. Of a diverse range of heterocyclic derivatives, 3-(2-thienyl) analogue 28 and 3-(3-thienyl) analogue 29 displayed the highest potency in human MCF-7 breast cancer cells with IC50 values of 7 nM and 10 nM, respectively, comparable to combretastatin A-4. Compounds from this series also exhibited potent activity in MDA-MB-231 breast cancer cells and in the NCI60 cell line panel. No significant toxicity was observed in normal murine breast epithelial cells. The presence of larger, bulkier groups at the 3-position, for example, 3-naphthyl derivative 21 and 3-benzothienyl derivative 26, resulted in relatively lower antiproliferative activity in the micromolar range. Tubulin-binding studies of 28 (IC50 = 1.37 lM) confirmed that the molecular target of this series of compounds is tubulin. These novel 3-(thienyl) b-lactam antiproliferative agents are useful scaffolds for the development of tubulin-targeting drugs. Refereed/Peer-reviewed
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- 2011
56. Non-Nucleoside Inhibitors of Human Adenosine Kinase: Synthesis, Molecular Modeling, and Biological Studies
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Sandra Gemma, Giovanni Maga, Stefania Butini, Ettore Novellino, Federico Da Settimo, Giuseppe Borrelli, Valeria La Pietra, Andrea Lossani, Daniela M. Zisterer, F. Focher, Andrea Torti, Stefania Sartini, Isabella Fiorini, Seema-Maria Nathwani, Giuseppe Campiani, Stefania Lamponi, Luciana Marinelli, Concettina La Motta, Anna Maria Ponte, Margherita Brindisi, Butini, S., Gemma, S., Brindisi, M., Borrelli, G., Lossani, A., Ponte, A. M., Torti, A., Maga, G., Marinelli, Luciana, LA PIETRA, Valeria, Fiorini, I., Lamponi, S., Campiani, G., Zisterer, D. M., Nathwani, S. M., Sartini, S., La Motta, C., Da Settimo, F., Novellino, Ettore, and Focher, F.
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Models, Molecular ,Adenosine Kinase Inhibitors ,Molecular model ,Stereochemistry ,Antineoplastic Agents ,Apoptosis ,Adenosine kinase ,Mice ,Structure-Activity Relationship ,Allosteric Regulation ,Cell Line, Tumor ,Drug Discovery ,medicine ,Animals ,Humans ,Pyrroles ,Adenosine Kinase ,Cell Proliferation ,chemistry.chemical_classification ,Biological studies ,biology ,Chemistry ,Stereoisomerism ,DNA ,Adenosine ,Recombinant Proteins ,Oxazepines ,Enzyme ,Biochemistry ,biology.protein ,RNA ,Molecular Medicine ,Phosphorylation ,Drug Screening Assays, Antitumor ,Nucleoside ,Allosteric Site ,medicine.drug - Abstract
Adenosine kinase (AK) catalyzes the phosphorylation of adenosine (Ado) to AMP by means of a kinetic mechanism in which the two substrates Ado and ATP bind the enzyme in a binary and/or ternary complex, with distinct protein conformations. Most of the described inhibitors have Ado-like structural motifs and are nonselective, and some of them (e.g., the tubercidine-like ligands) are characterized by a toxic profile. We have cloned and expressed human AK (hAK) and searched for novel non-substrate-like inhibitors. Our efforts to widen the structural diversity of AK inhibitors led to the identification of novel non-nucleoside, noncompetitive allosteric modulators characterized by a unique molecular scaffold. Among the pyrrolobenzoxa(thia)zepinones (4a-qq) developed, 4a was identified as a non-nucleoside prototype hAK inhibitor. 4a has proapoptotic efficacy, slight inhibition of short-term RNA synthesis, and cytostatic activity on tumor cell lines while showing low cytotoxicity and no significant adverse effects on short-term DNA synthesis in cells.
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- 2011
57. Synthesis and Evaluation of Azetidinone Analogues of Combretastatin A-4 as Tubulin Targeting Agents
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Niamh M. O’Boyle, Thomas McCabe, David Lloyd, Miriam Carr, Daniela M. Zisterer, Orla Bergin, Seema M. Nathwani, Mary J. Meegan, Lisa M. Greene, O'Boyle, NM, Carr, M, Greene, LM, Bergin, O, Nathwani, SM, McCabe, Thomas, Lloyd, David George, Zisterer, DM, and Meegan, MJ
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Models, Molecular ,β-lactam ,Crystallography, X-Ray ,Biochemistry ,01 natural sciences ,Compound 32 ,chemistry.chemical_compound ,0302 clinical medicine ,Tubulin ,Stilbenes ,Drug Discovery ,Cytotoxicity ,Combretastatin A-4 analogues ,azetidinone ,Molecular Structure ,biology ,Stereoisomerism ,Tubulin Modulators ,3. Good health ,030220 oncology & carcinogenesis ,cytotoxicity ,Molecular Medicine ,Female ,Protein Binding ,structure-activity ,Stereochemistry ,colchicine ,Structure-Activity Relationship ,03 medical and health sciences ,Mammary Glands, Animal ,Cell Line, Tumor ,Animals ,Humans ,Structure–activity relationship ,Combretastatin ,Combretastatin A-4 ,010405 organic chemistry ,Epithelial Cells ,In vitro ,0104 chemical sciences ,Medicinal Chemistry and Pharmaceutics ,tubulin ,chemistry ,biology.protein ,Azetidines ,Cattle ,Drug Screening Assays, Antitumor - Abstract
The synthesis and antiproliferative activity of a new series of rigid analogues of combretastatin A-4 are described which contain the 1,4-diaryl-2-azetidinone (β-lactam) ring system in place of the usual ethylene bridge present in the natural combretastatin stilbene products. These novel compounds are also substituted at position 3 of the β-lactam ring with an aryl ring. A number of analogues showed potent nanomolar activity in human MCF-7 and MDA-MB-231 breast cancer cell lines, displayed in vitro inhibition of tubulin polymerization, and did not cause significant cytotoxicity in normal murine breast epithelial cells. 4-(4-Methoxyaryl)-substituted compound 32, 4-(3-hydroxy-4-methoxyaryl)-substituted compounds 35 and 41, and the 3-(4-aminoaryl)-substituted compounds 46 and 47 displayed the most potent antiproliferative activity of the series. β-Lactam 41 in particular showed subnanomolar activity in MCF-7 breast cancer cells (IC50=0.8 nM) together with significant in vitro inhibition of tubulin polymerization and has been selected for further biochemical assessment. These novel β-lactam compounds are identified as potentially useful scaffolds for the further development of antitumor agents that target tubulin. Refereed/Peer-reviewed
- Published
- 2010
58. The Vascular Targeting Agent Combretastatin-A4 and a Novelcis-Restricted β-Lactam Analogue, CA-432, Induce Apoptosis in Human Chronic Myeloid Leukemia Cells and Ex Vivo Patient Samples Including Those Displaying Multidrug Resistance
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Miriam Carr, Daniela M. Zisterer, Niamh M. O’Boyle, Balázs Sarkadi, Mary J. Meegan, Aisling Croke, David Lloyd, Seema M. Nathwani, Peig Carroll, Lisa M. Greene, Mark Lawler, Anthony M. McElligott, Eibhlin Conneally, Niall O. Keely, Sandra A. Bright, Maria Gagliardi, Lisa M. O’Connor, Darren Fayne, Greene, LM, Nathwani, SM, Bright, SA, Fayne, D, Croke, A, Gagliardi, M, McElligott, AM, O'Connor, L, Carr, M, Keely, NO, O'Boyle, NM, Carroll, P, Sarkadi, B, Conneally, E, Lloyd, David George, Lawler, M, Meegan, MJ, and Zisterer, DM
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Combretum caffrum ,Cell Survival ,African willow tree ,Blotting, Western ,Apoptosis ,HL-60 Cells ,Biology ,beta-Lactams ,Microtubules ,Tubulin ,hemic and lymphatic diseases ,Stilbenes ,medicine ,Humans ,Cell Proliferation ,Pharmacology ,Microscopy, Confocal ,Molecular Structure ,Cell Cycle ,Guaiacol ,Myeloid leukemia ,Stereoisomerism ,Cell cycle ,Mitotic spindle checkpoint ,biology.organism_classification ,Antineoplastic Agents, Phytogenic ,Drug Resistance, Multiple ,Dasatinib ,Imatinib mesylate ,Microscopy, Fluorescence ,Biochemistry ,Drug Resistance, Neoplasm ,Cancer research ,Azetidines ,Molecular Medicine ,K562 Cells ,Ex vivo ,medicine.drug ,K562 cells - Abstract
Combretastatin-A4 (CA-4) is a natural derivative of the African willow tree Combretum caffrum. CA-4 is one of the most potent antimitotic components of natural origin, but it is, however, intrinsically unstable. A novel series of CA-4 analogs incorporating a 3,4-diaryl-2-azetidinone (β-lactam) ring were designed and synthesized with the objective to prevent cis-trans isomerization and improve the intrinsic stability without altering the biological activity of CA-4. Evaluation of selected -lactam CA-4 analogs demonstrated potent antitubulin, antiproliferative, and antimitotic effects in human leukemia cells. A lead -lactam analog, CA-432, displayed comparable antiproliferative activities with CA-4. CA-432 induced rapid apoptosis in HL-60 acute myeloid leukemia cells, which was accompanied by depolymerization of the microtubular network, poly(ADPribose) polymerase cleavage, caspase-3 activation, and Bcl-2 cleavage. A prolonged G2M cell cycle arrest accompanied by a sustained phosphorylation of mitotic spindle checkpoint protein, BubR1, and the antiapoptotic proteins Bcl-2 and Bcl-xL preceded apoptotic events in K562 chronic myeloid leukemia (CML) cells. Molecular docking studies in conjunction with comprehensive cell line data rule out CA-4 and β-lactam derivatives as P-glycoprotein substrates. Furthermore, both CA-4 and CA-432 induced significantly more apoptosis compared with imatinib mesylate in ex vivo samples from patients with CML, including those positive for the T315I mutation displaying resistance to imatinib mesylate and dasatinib. In summary, synthetic intrinsically stable analogs of CA-4 that display significant clinical potential as antileukemic agents have been designed and synthesized. Refereed/Peer-reviewed
- Published
- 2010
59. Sequential treatment with flavopiridol synergistically enhances pyrrolo-1,5-benzoxazepine-induced apoptosis in human chronic myeloid leukaemia cells including those resistant to imatinib treatment
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Michael W. Deininger, Mark Lawler, D. Clive Williams, Sandra A. Bright, Daniela M. Zisterer, and Giuseppe Campiani
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Survivin ,Down-Regulation ,Antineoplastic Agents ,Apoptosis ,Pharmacology ,Inhibitor of apoptosis ,Biochemistry ,Piperazines ,Inhibitor of Apoptosis Proteins ,Piperidines ,Cyclin-dependent kinase ,Leukemia, Myelogenous, Chronic, BCR-ABL Positive ,hemic and lymphatic diseases ,Humans ,Pyrroles ,Cyclin B1 ,Protein Kinase Inhibitors ,Flavonoids ,Cyclin-dependent kinase 1 ,biology ,Drug Synergism ,Cell cycle ,Oxazepines ,Pyrimidines ,Imatinib mesylate ,Drug Resistance, Neoplasm ,Benzamides ,Imatinib Mesylate ,biology.protein ,Cancer research ,Microtubule-Associated Proteins - Abstract
The Bcr-Abl kinase inhibitor, imatinib mesylate, is the front line treatment for chronic myeloid leukaemia (CML), but the emergence of imatinib resistance has led to the search for alternative drug treatments and the examination of combination therapies to overcome imatinib resistance. The pro-apoptotic PBOX compounds are a recently developed novel series of microtubule targeting agents (MTAs) that depolymerise tubulin. Recent data demonstrating enhanced MTA-induced tumour cell apoptosis upon combination with the cyclin dependent kinase (CDK)-1 inhibitor flavopiridol prompted us to examine whether this compound could similarly enhance the effect of the PBOX compounds. We thus characterised the apoptotic and cell cycle events associated with combination therapy of the PBOX compounds and flavopiridol and results showed a sequence dependent, synergistic enhancement of apoptosis in CML cells including those expressing the imatinib-resistant T315I mutant. Flavopiridol reduced the number of polyploid cells formed in response to PBOX treatment but only to a small extent, suggesting that inhibition of endoreplication was unlikely to play a major role in the mechanism by which flavopiridol synergistically enhanced PBOX-induced apoptosis. The addition of flavopiridol following PBOX-6 treatment did however result in an accelerated exit from the G2/M transition accompanied by an enhanced downregulation and deactivation of the CDK1/cyclin B1 complex and an enhanced degradation of the inhibitor of apoptosis protein (IAP) survivin. In conclusion, results from this study highlight the potential of these novel series of PBOX compounds, alone or in sequential combination with flavopiridol, as an effective therapy against CML.
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- 2010
60. Novel pyrrolo-1,5-benzoxazepine compounds display significant activity against resistant chronic myeloid leukaemia cells in vitro, in ex vivo patient samples and in vivo
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Mark Lawler, Michael W. Deininger, J W O'Connell, D. C. Williams, Eibhlin Conneally, Sandra A. Bright, Peig Carroll, Giuseppe Campiani, Anthony M. McElligott, Daniela M. Zisterer, and Lisa M. O’Connor
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Adult ,Male ,Cancer Research ,Cell Survival ,Blotting, Western ,Antineoplastic Agents ,Apoptosis ,Cell Separation ,Biology ,Genes, abl ,Philadelphia chromosome ,Mice ,PBOX ,In vivo ,hemic and lymphatic diseases ,Cell Line, Tumor ,Leukemia, Myelogenous, Chronic, BCR-ABL Positive ,medicine ,T315I ,Animals ,Humans ,Pyrroles ,Viability assay ,neoplasms ,CML ,Aged ,Mice, Inbred BALB C ,breakpoint cluster region ,Imatinib ,Middle Aged ,medicine.disease ,Flow Cytometry ,Oxazepines ,Oncology ,Drug Resistance, Neoplasm ,Mutation ,Cancer research ,Female ,Translational Therapeutics ,Tyrosine kinase ,Ex vivo ,Chronic myelogenous leukemia ,medicine.drug ,Bcr-Abl - Abstract
Background: Imatinib is a direct and potent inhibitor of the constitutively active tyrosine kinase, breakpoint cluster region-Abelson (Bcr-Abl), which is central to the pathogenesis of chronic myeloid leukaemia (CML) patients. As such, imatinib has become the front-line treatment for CML patients. However, the recent emergence of imatinib resistance, commonly associated with point mutations within the kinase domain, has led to the search for alternative drug treatments and combination therapies for CML. Methods: In this report, we analyse the effects of representative members of the novel pro-apoptotic microtubule depolymerising pyrrolo-1,5-benzoxazepines or PBOX compounds on chemotherapy-refractory CML cells using a series of Bcr-Abl mutant cell lines, clinical ex vivo patient samples and an in vivo mouse model. Results: The PBOX compounds potently reduce cell viability in cells expressing the E225K and H396P mutants as well as the highly resistant T315I mutant. The PBOX compounds also induce apoptosis in primary CML samples including those resistant to imatinib. We also show for the first time, the in vivo efficacy of the pro-apoptotic PBOX compound, PBOX-6, in a CML mouse model of the T315I Bcr-Abl mutant. Conclusion: Results from this study highlight the potential of these novel series of PBOX compounds as an effective therapy against CML.
- Published
- 2010
61. The Novel Tubulin-Targeting Agent Pyrrolo-1,5-Benzoxazepine-15 Induces Apoptosis in Poor Prognostic Subgroups of Chronic Lymphocytic Leukemia
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Paul Browne, Mark Catherwood, Lisa M. Greene, Mark Lawler, D. Clive Williams, Elaina N. Maginn, Amjad Hayat, Elisabeth Vandenberghe, Stefania Butini, Daniela M. Zisterer, Anthony M. McElligott, Siobhan McGuckin, and Giuseppe Campiani
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Male ,Cancer Research ,Chronic lymphocytic leukemia ,protein-kinase ,Apoptosis ,CD38 ,Microtubules ,Tubulin ,hemic and lymphatic diseases ,DNA (Cytosine-5-)-Methyltransferases ,Cytotoxicity ,Aged, 80 and over ,Caspase 8 ,ZAP-70 Protein-Tyrosine Kinase ,cml cells ,tyrosine kinase ,Middle Aged ,Prognosis ,Fludarabine ,Leukemia ,Haematopoiesis ,Oncology ,Female ,cd38 expression ,Immunoglobulin Heavy Chains ,bcl-2 phosphorylation ,Vidarabine ,medicine.drug ,Adult ,Immunoblotting ,B-cell receptor ,Antineoplastic Agents ,in-vitro ,Biology ,medicine ,up-regulation ,Humans ,Pyrroles ,Aged ,cll cells ,b-cell receptor ,JNK Mitogen-Activated Protein Kinases ,Granulocyte-Macrophage Colony-Stimulating Factor ,medicine.disease ,Leukemia, Lymphocytic, Chronic, B-Cell ,Oxazepines ,Immunology ,Cancer research ,activation - Abstract
Pyrrolo-1,5-benzoxazepine-15 (PBOX-15) is a novel microtubule depolymerization agent that induces cell cycle arrest and subsequent apoptosis in a number of cancer cell lines. Chronic lymphocytic leukemia (CLL) is characterized by clonal expansion of predominately nonproliferating mature B cells. Here, we present data suggesting PBOX-15 is a potential therapeutic agent for CLL. We show activity of PBOX-15 in samples taken from a cohort of CLL patients (n = 55) representing both high-risk and low-risk disease. PBOX-15 exhibited cytotoxicity in CLL cells (n = 19) in a dose-dependent manner, with mean IC50 of 0.55 μmol/L. PBOX-15 significantly induced apoptosis in CLL cells (n = 46) including cells with poor prognostic markers: unmutated IgVH genes, CD38 and zeta-associated protein 70 (ZAP-70) expression, and fludarabine-resistant cells with chromosomal deletions in 17p. In addition, PBOX-15 was more potent than fludarabine in inducing apoptosis in fludarabine-sensitive cells. Pharmacologic inhibition and small interfering RNA knockdown of caspase-8 significantly inhibited PBOX-15–induced apoptosis. Pharmacologic inhibition of c-jun NH2-terminal kinase inhibited PBOX-15–induced apoptosis in mutated IgVH and ZAP-70− CLL cells but not in unmutated IgVH and ZAP-70+ cells. PBOX-15 exhibited selective cytotoxicity in CLL cells compared with normal hematopoietic cells. Our data suggest that PBOX-15 represents a novel class of agents that are toxic toward both high-risk and low-risk CLL cells. The need for novel treatments is acute in CLL, especially for the subgroup of patients with poor clinical outcome and drug-resistant disease. This study identifies a novel agent with significant clinical potential. [Cancer Res 2009;69(21):8366–75]
- Published
- 2009
62. Synthesis, biological evaluation, structural–activity relationship, and docking study for a series of benzoxepin-derived estrogen receptor modulators
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David Lloyd, Mary J. Meegan, Andrew J. S. Knox, Rosario B. Hughes, Irene Barrett, Natalia Artemenko, Georgia Golfis, Miriam Carr, Daniela M. Zisterer, Barrett, Irene, Meegan, Mary J, Hughes, Rosario B, Carr, Miriam, Knox, Andrew JS, Artemenko, Natalia, Golfis, Georgia, Zisterer, Daniela M, and Lloyd, David G
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Models, Molecular ,antiproliferative activity ,Quantitative structure–activity relationship ,Stereochemistry ,medicine.drug_class ,Clinical Biochemistry ,Pharmaceutical Science ,Estrogen receptor ,Biochemistry ,Estrogen Receptor Modulators ,Benzoxepin ,Drug Discovery ,Tumor Cells, Cultured ,benzoxepin ,medicine ,Benzoxepins ,Estrogen Receptor beta ,Humans ,skin and connective tissue diseases ,Molecular Biology ,Cell Proliferation ,Molecular Structure ,QSAR ,Chemistry ,Organic Chemistry ,Estrogen Receptor alpha ,Antiestrogen ,Docking (molecular) ,Estrogen ,Selective estrogen receptor modulator ,docking ,Molecular Medicine ,Female ,estrogen receptor antagonist ,hormones, hormone substitutes, and hormone antagonists ,Tamoxifen ,medicine.drug - Abstract
The estrogen receptors ERα and ERβ are recognized as important pharmaceutical targets for a variety of diseases including osteoporosis and breast cancer. A series of novel benzoxepin-derived compounds are described as potent selective modulators of the human estrogen receptor modulators (SERMs). We report the antiproliferative effects of these compounds on human MCF-7 breast tumor cells. These heterocyclic compounds contain the triarylethylene arrangement as exemplified by tamoxifen, conformationally restrained through the incorporation of the benzoxepin ring system. The compounds demonstrate potency at nanomolar concentrations in antiproliferative assays against an MCF-7 human breast cancer cell line with low cytotoxicity together with low nanomolar binding affinity for the estrogen receptor. The compounds also demonstrate potent antiestrogenic properties in the human uterine Ishikawa cell line. The effect of a number of functional group substitutions on the ER binding properties of the benzoxepin molecular scaffold is examined through a detailed docking and 2D-QSAR computational investigation. The best QSAR model developed for ERαβ selectivity yielded R2 of 0.84 with an RMSE for the training set of 0.30. The predictive quality of the model was Q2 of 0.72 and RMSE of 0.18 for the test set. One particular compound (26b) bearing a 4-fluoro substituent, exhibits 15-fold selectivity for ERb and both our docking and QSAR studies converge on the correlation between enhanced lipophilicity and enhanced ERb binding for this benzoxepin ring scaffold. Refereed/Peer-reviewed
- Published
- 2008
63. Flexible Estrogen Receptor Modulators: Synthesis, Biochemistry and Molecular Modeling Studies for 3-Benzyl-4,6-diarylhex-3-ene and 3,4,6-Triarylhex-3-ene Derivatives
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Daniela M. Zisterer, David Lloyd, Helena M. Smith, Mary J. Meegan, and Andrew J. S. Knox
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Models, Molecular ,Selective Estrogen Receptor Modulators ,Cell Survival ,Stereochemistry ,Estrogen receptor ,Antineoplastic Agents ,Breast Neoplasms ,Alkenes ,Ligands ,chemistry.chemical_compound ,Cell Line, Tumor ,Drug Discovery ,medicine ,Humans ,Raloxifene ,Toremifene ,Ene reaction ,Cell Proliferation ,L-Lactate Dehydrogenase ,Aryl ,Receptors, Estrogen ,chemistry ,Selective estrogen receptor modulator ,Female ,Indicators and Reagents ,Estrogen receptor alpha ,hormones, hormone substitutes, and hormone antagonists ,Tamoxifen ,medicine.drug - Abstract
Selective estrogen receptor modulators (SERMs) such as tamoxifen and toremifene are clinically useful drugs in the endocrine treatment of estrogen receptor positive breast cancer while raloxifene is an effective intervention for osteoporosis. In an ongoing SERM discovery programme we now report the synthesis of a series of 3-benzyl-4,6-diarylhex-3-enes and 3,4,6-triarylhex-3-enes containing an extended flexible core structure. In these novel structures, the ethylene group acts as a flexible spacing group linking the aryl Ring A or Ring B with the core alkene group. In the benzyl-4,6-diarylhex-3-ene series an additional methylene group is inserted as a spacing group between the aryl ring C and the ethylene core group. These products demonstrated antiproliferative activity against the MCF-7 human breast cancer cell line. The alkene compounds were also shown to have binding affinity for the estrogen receptor alpha (IC50 values for the most active compounds in the range 0.110-0.293 microM) together with selectivity for ER alpha/beta. The compounds demonstrated antiestrogenic activity in Ishikawa cells with low estrogenic stimulation. The structure-activity relationships for the active ligands were further explored in a computational study where docked structures of the active compounds were compared with the X-ray crystal structures for the complexes of ER alpha with 4-hydroxytamoxifen and ER beta with raloxifene. The alignment of the aromatic rings B and C of the compounds within the ligand binding domain could then be correlated with their observed ER alpha/beta selectivity.
- Published
- 2007
64. Unconventional Knoevenagel-type indoles: Synthesis and cell-based studies for the identification of pro-apoptotic agents
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Margherita Brindisi, Silvana Alfei, Stefania Butini, Giuseppina Sanna, Sandra A. Bright, Sandra Gemma, Daniela M. Zisterer, Andrea Spallarossa, Matteo Caviglia, Giuseppe Campiani, Giovanni Maga, Chiara Caneva, Gabriella Collu, Emmanuele Crespan, Clive D. Williams, Roberta Loddo, Ilenia Delogu, Spallarossa, Andrea, Caneva, Chiara, Caviglia, Matteo, Alfei, Silvana, Butini, Stefania, Campiani, Giuseppe, Gemma, Sandra, Brindisi, Margherita, Zisterer Daniela, M., Bright Sandra, A., Williams Clive, D., Crespan, Emmanuele, Maga, Giovanni, Sanna, Giuseppina, Delogu, Ilenia, Collu, Gabriella, and Loddo, Roberta
- Subjects
Indoles ,Stereochemistry ,HL60 ,Cell ,Antineoplastic Agents ,Apoptosis ,HL-60 Cells ,Pro-apoptotic agent ,Structure-Activity Relationship ,chemistry.chemical_compound ,Tubulin immunostaining ,Drug Discovery ,medicine ,Humans ,Structure–activity relationship ,Antiproliferative agents ,Pro-apoptotic agents ,Drug Discovery3003 Pharmaceutical Science ,Organic Chemistry ,Pharmacology ,Cell Proliferation ,Indole test ,Molecular Structure ,Cell growth ,General Medicine ,Cell cycle ,medicine.anatomical_structure ,chemistry ,Cell culture ,Antiproliferative agent ,Indole ,MCF-7 Cells ,Knoevenagel condensation ,Drug Screening Assays, Antitumor ,K562 Cells - Abstract
A new series of indole-based analogues were recently identified as potential anticancer agents. The Knoevenagel-type indoles herein presented were prepared via a one-pot condensation of iminium salts with active methylene reagents and were isolated as single geometric isomers. Biological evaluation in different cell-based assays revealed an antiproliferative activity for some analogues already in the nanomolar range against leukaemia, breast and renal cancer cell lines. To explain these effects, the most promising analogues of the series were engaged in further cell-based studies. Compounds 5e, l, p and 6a, b highlighted a pro-apoptotic potential being able to induce apoptosis in HL60, K562 and MCF-7 cell lines in a dose and time-dependent manner. The ability of these compounds to arrest cell cycle at the G2/M phase inspired the immunofluorescence studies which allowed us to identify tubulin as a potential target for compounds 5l and 6b.
- Published
- 2015
65. Identification of Tubulin as the Molecular Target of Proapoptotic Pyrrolo-1,5-benzoxazepines
- Author
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Mark Lawler, Caterina Fattorusso, Daniela M. Zisterer, Lisa M. Greene, Suzanne M. Cloonan, Jude M. Mulligan, D. Clive Williams, Giuseppe Campiani, Valeria Onnis, Margaret M. Mc Gee, Mulligan, J. M., Greene, L. M., Cloonan, S, Mcgee, M. M., Onnis, V, Campiani, G, Fattorusso, Caterina, Lawler, M, Williams, D. C., and Zisterer, D. M.
- Subjects
G2 Phase ,Time Factors ,Blotting, Western ,Cyclin B ,Apoptosis ,Biology ,Vinblastine ,Binding, Competitive ,Microtubules ,chemistry.chemical_compound ,Tubulin ,Microtubule ,Cell Line, Tumor ,CDC2 Protein Kinase ,Humans ,Pyrroles ,Cyclin B1 ,Metaphase ,Pharmacology ,Cyclin-dependent kinase 1 ,Binding Sites ,Dose-Response Relationship, Drug ,Antineoplastic Agents, Phytogenic ,Cell biology ,Oxazepines ,Nocodazole ,chemistry ,Paclitaxel ,biology.protein ,Molecular Medicine ,Carbamates ,Colchicine ,K562 Cells ,Cell Division - Abstract
We have demonstrated previously that certain members of a series of novel pyrrolo-1,5-benzoxazepine (PBOX) compounds potently induce apoptosis in a variety of human chemotherapy-resistant cancer cell lines and in primary ex vivo material derived from cancer patients. A better understanding of the molecular mechanisms underlying the apoptotic effects of these PBOX compounds is essential to their development as antineoplastic therapeutic agents. This study sought to test the hypothesis that proapoptotic PBOX compounds target the microtubules. We show that a representative proapoptotic PBOX compound, PBOX-6, induces apoptosis in both the MCF-7 and K562 cell lines. An accumulation of cells in G2/M precedes apoptosis in response to PBOX-6. PBOX-6 induces prometaphase arrest and causes an accumulation of cyclin B1 levels and activation of cyclin B1/CDK1 kinase in a manner similar to that of two representative antimicrotubule agents, nocodazole and paclitaxel. Indirect immunofluorescence demonstrates that both PBOX-6 and another pro-apoptotic PBOX compound, PBOX-15, cause microtubule depolymerization in MCF-7 cells. They also inhibit the assembly of purified tubulin in vitro, whereas a nonapoptotic PBOX compound (PBOX-21) has no effect on either the cellular microtubule network or on the assembly of purified tubulin. This suggests that the molecular target of the pro-apoptotic PBOX compounds is tubulin. PBOX-6 does not bind to either the vinblastine or the colchicine binding site on tubulin, suggesting that it binds to an as-yet-uncharacterised novel site on tubulin. The ability of PBOX-6 to bind tubulin and cause microtubule depolymerization confirms it as a novel candidate for antineoplastic therapy.
- Published
- 2006
66. Pyrrolo[1,5]benzoxa(thia)zepines as a New Class of Potent Apoptotic Agents. Biological Studies and Identification of an Intracellular Location of Their Drug Target
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Carla Cucco, C. Pisano, D. Clive Williams, Vito Nacci, Daniela M. Zisterer, Ettore Novellino, Margaret M. Mc Gee, Stefania Butini, Caterina Fattorusso, Sandra Gemma, Giuseppe Campiani, Bruno Catalanotti, Gagan Kukreja, Isabella Fiorini, Anna Ramunno, Mcgee, M., Gemma, S., Butini, S., Ramunno, A., Zisterer, D. M., Fattorusso, Caterina, Catalanotti, Bruno, Kukreja, G., Fiorini, I., Pisano, C., Cucco, C., Novellino, Ettore, Nacci, V., Williams, D. C., and Campiani, G.
- Subjects
Models, Molecular ,Thiazepines ,Antineoplastic Agents ,Apoptosis ,HL-60 Cells ,In vivo ,Cell Line, Tumor ,Drug Discovery ,medicine ,Humans ,Cytotoxic T cell ,Cytotoxicity ,Molecular Structure ,Chemistry ,Biological Transport ,In vitro ,Benzoxazines ,Mechanism of action ,Biochemistry ,Cell culture ,Drug Design ,Cancer research ,Molecular Medicine ,medicine.symptom ,K562 Cells ,Intracellular - Abstract
We have recently developed five novel pyrrolo-1,5-benzoxazepines as proapoptotic agents. Their JNK-dependent induction of apoptosis in tumor cells suggested their potential as novel anticancer agents. The core structure of the apoptotic agent 6 was investigated, and the SARs were expanded with the design and synthesis of several analogues. To define the apoptotic mechanism of the new compounds and the localization of their drug target, two analogues of 6 were designed and synthesized to delineate events leading to JNK activation. The cell-penetrating compound 16 induced apoptosis in tumor cells, while its nonpenetrating analogue, 17, was incapable of inducing apoptosis or activating JNK. Plasma membrane permeabilization of tumor cells resulted in 17-induced JNK activation, suggesting that the pyrrolo-1,5-benzoxazepine molecular target is intracellular. Interestingly, compound 6 displayed cytotoxic activity against a panel of human tumor cell lines but demonstrated negligible toxicity in vivo with no effect on the animals' hematology parameters.
- Published
- 2005
67. Activation of the c-Jun N-terminal Kinase (JNK) Signaling Pathway Is Essential during PBOX-6-induced Apoptosis in Chronic Myelogenous Leukemia (CML) Cells
- Author
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Anna Ramunno, Margaret M. Mc Gee, Vito Nacci, D. Clive Williams, Giuseppe Campiani, Daniela M. Zisterer, and Mark Lawler
- Subjects
Dicumarol ,Proto-Oncogene Proteins c-jun ,p38 mitogen-activated protein kinases ,Antineoplastic Agents ,Apoptosis ,Mitogen-activated protein kinase kinase ,Biochemistry ,Substrate Specificity ,MAP2K7 ,Leukemia, Myelogenous, Chronic, BCR-ABL Positive ,Humans ,Pyrroles ,Enzyme Inhibitors ,Phosphorylation ,Cyclic AMP Response Element-Binding Protein ,Molecular Biology ,Adaptor Proteins, Signal Transducing ,Activating Transcription Factor 2 ,biology ,MAP kinase kinase kinase ,Kinase ,c-jun ,JNK Mitogen-Activated Protein Kinases ,Cell Biology ,Activating transcription factor 2 ,Cell biology ,Enzyme Activation ,Oxazepines ,Cancer research ,biology.protein ,Mitogen-Activated Protein Kinases ,Carrier Proteins ,K562 Cells ,Signal Transduction ,Transcription Factors ,K562 cells - Abstract
The mitogen-activated protein (MAP) kinase family is activated in response to a wide variety of external stress signals such as UV irradiation, heat shock, and many chemotherapeutic drugs and leads to the induction of apoptosis. A novel series of pyrrolo-1,5-benzoxazepines have been shown to potently induce apoptosis in chronic myelogenous leukemia (CML) cells, which are resistant to many chemotherapeutic agents. In this study we have delineated part of the mechanism by which a representative compound known as PBOX-6 induces apoptosis. We have investigated whether PBOX-6 induces activation of MAP kinase signaling pathways in CML cells. Treatment of K562 cells with PBOX-6 resulted in the transient activation of two JNK isoforms, JNK1 and JNK2. In contrast, PBOX-6 did not activate the extracellular signal-regulated kinase (ERK) or p38. Apoptosis was found to occur independently of the small GTPases Ras, Rac, and Cdc42 but involved phosphorylation of the JNK substrates, c-Jun and ATF-2. Pretreatment of K562 cells with the JNK inhibitor, dicoumarol, abolished PBOX-6-induced phosphorylation of c-Jun and ATF-2 and inhibited the induced apoptosis, suggesting that JNK activation is an essential component of the apoptotic pathway induced by PBOX-6. Consistent with this finding, transfection of K562 cells with the JNK scaffold protein, JIP-1, inhibited JNK activity and apoptosis induced by PBOX-6. JIP-1 specifically scaffolds JNK, MKK7, and members of the mixed-lineage kinase (MLK) family, implicating these kinases upstream of JNK in the apoptotic pathway induced by PBOX-6 in K562 cells.
- Published
- 2002
68. In vitro cytotoxicity of a composite resin and compomer
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C. A. Quinlan, Michael O'Sullivan, Daniela M. Zisterer, and Keith F. Tipton
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Programmed cell death ,Necrosis ,Materials science ,Light ,Cell Survival ,Statistics as Topic ,Tetrazolium Salts ,Apoptosis ,Pilot Projects ,Composite Resins ,Dental Materials ,chemistry.chemical_compound ,Leukemia, Promyelocytic, Acute ,In vivo ,Lactate dehydrogenase ,Materials Testing ,medicine ,Humans ,Endothelium ,Viability assay ,Coloring Agents ,Cytotoxicity ,General Dentistry ,Cells, Cultured ,Caspase ,Enzyme Precursors ,Cell Death ,L-Lactate Dehydrogenase ,biology ,Caspase 3 ,Compomers ,Silicates ,Molecular biology ,Thiazoles ,chemistry ,Caspases ,Dentin ,Immunology ,biology.protein ,Methacrylates ,medicine.symptom - Abstract
Aim This work was designed to investigate the potential cytotoxicity of two of the newer dental restorative materials, Spectrum® composite resin and Dyract® AP compomer. Methodology Cultured human endothelial cells (ECV-304) were exposed to each of the restorative materials through a 70-µm dentine barrier to simulate the in vivo clinical situation. Cell viability was measured by the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide) assay and lactate dehydrogenase release assay. The effects of different extents of light-curing were also examined by microscopic examination of stained human promyelocytic leukemia cells (HL-60). Caspase-3 activation was determined as a measure of apoptotic cell death. Results Assessment of cellular viability indicated that both materials cause cell death, with Spectrum® being the more toxic. The cytotoxicity was considerably increased in the absence of the dentine barrier. Direct exposure to Spectrum® for 12 h resulted in the death of 69% of the cells after full light-curing (78% of total death was by apoptosis) and 96% after partial light-curing (73% of total death was by necrosis). Assessment of caspase activation, in the absence of the dentine barrier, showed that longer curing-times resulted in an increase in the proportion of the cells dying through apoptosis, rather than necrosis, for both materials tested. Conclusions These results indicate the restorative materials to be potentially toxic, particularly if the degree of light-cure is inadequate.
- Published
- 2002
69. β-Lactam Estrogen Receptor Antagonists and a Dual-targeting Estrogen Receptor/tubulin Ligand
- Author
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Andrew J. S. Knox, Niamh M. O’Boyle, Shu Wang, Laura Caboni, Seema M. Nathwani, Miriam Carr, Daniela M. Zisterer, Jade K. Pollock, and Mary J. Meegan
- Subjects
Models, Molecular ,β-lactam ,Chemistry, Pharmaceutical ,Tetrazolium Salts ,Estrogen receptor ,Apoptosis ,Plasma protein binding ,Ligands ,Biochemistry ,Estrogen Receptor Antagonists ,Tubulin ,designed multiple ligand ,Heterocyclic Compounds ,Drug Discovery ,Organic Chemicals ,azetidinone ,biology ,Chemistry ,Ligand (biochemistry) ,Hormones, Hormone Substitutes, and Hormone Antagonists ,Proto-Oncogene Proteins c-bcl-2 ,MCF-7 Cells ,Molecular Medicine ,Cell Division ,Protein Binding ,estrogen receptor ,G2 Phase ,Chemical Actions and Uses ,beta-Lactams ,Inhibitory Concentration 50 ,Downregulation and upregulation ,Estrogen Receptor beta ,Humans ,Computer Simulation ,polypharmacy ,Estrogen receptor beta ,L-Lactate Dehydrogenase ,Estrogen Receptor alpha ,Estrogens ,SERM ,Thiazoles ,Medicinal Chemistry and Pharmaceutics ,tubulin ,biology.protein ,Myeloid Cell Leukemia Sequence 1 Protein ,Antiproliferative ,Estrogen receptor alpha ,Software ,Other Chemicals and Drugs - Abstract
Twelve novel β-lactams were synthesized and their antiproliferative effects and binding affinity for the predominant isoforms of the estrogen receptor (ER), ERα and ERβ, were determined. β-Lactams 23 and 26 had the strongest binding affinities for ERα (IC50 values: 40 and 8 nM, respectively) and ERβ (IC50 values: 19 and 15 nM). β-Lactam 26 was the most potent in antiproliferative assays using MCF-7 breast cancer cells, and further biochemical analysis showed that it caused accumulation of cells in G2/M phase (mitotic blockade) and depolymerization of tubulin in MCF-7 cells. Compound 26 also induced apoptosis and downregulation of the expression of pro-survival proteins Bcl-2 and Mcl-1. Computational modeling predicted binding preferences for the dual ER/tubulin ligand 26. This series is an important addition to the known pool of ER antagonists and β-lactam 26 is the first reported compound that has dual-targeting properties for both the ER and tubulin.
- Published
- 2014
70. The novel pyrrolo-1,5-benzoxazepine, PBOX-6, synergistically enhances the apoptotic effects of carboplatin in drug sensitive and multidrug resistant neuroblastoma cells
- Author
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Eilis Carroll, Giuseppe Campiani, Stefania Butini, Anne O'Meara, D. Clive Williams, Jennifer C. Lennon, Sandra A. Bright, and Daniela M. Zisterer
- Subjects
Antineoplastic Agents ,Apoptosis ,Pharmacology ,Biology ,Biochemistry ,Carboplatin ,Neuroblastoma ,chemistry.chemical_compound ,Downregulation and upregulation ,In vivo ,Cell Line, Tumor ,medicine ,Humans ,Pyrroles ,Doxorubicin ,Etoposide ,Drug Synergism ,medicine.disease ,Drug Resistance, Multiple ,Up-Regulation ,Multiple drug resistance ,Oxazepines ,chemistry ,Drug Resistance, Neoplasm ,medicine.drug - Abstract
Neuroblastoma, a malignancy of neuroectoderrmal origin, accounts for 15% of childhood cancer deaths. Despite advances in understanding the biology, it remains one of the most difficult paediatric cancers to treat. A major obstacle in the effective treatment of neuroblastoma is the development of multidrug resistance (MDR). There is thus a compelling demand for new treatment strategies for this cancer that can bypass such resistance mechanisms. The pyrrolo-1,5-benzoxazepine (PBOX) compounds are a series of novel microtubule-targeting agents that potently induce apoptosis in various cancer cell lines, ex vivo patient samples and in vivo cancer models. In this study we examined the ability of two members, PBOX-6 and -15, to exhibit anti-cancer effects in a panel of drug sensitive and MDR neuroblastoma cell lines. The PBOX compounds potently reduced the viability of all neuroblastoma cells examined and exhibited a lower fold resistance in MDR cells when compared to standard chemotherapeutics. In addition, the PBOX compounds synergistically enhanced apoptosis induced by etoposide, carboplatin and doxorubicin. Exposure of drug sensitive and resistant cell lines to PBOX-6/carboplatin induced cleavage of Bcl-2, a downregulation of Mcl-1 and a concomitant increase in Bak. Furthermore, activation of caspase-3, -8 and -9 was demonstrated. Finally, gene silencing of Mcl-1 by siRNA was shown to sensitise both drug sensitive and multidrug resistant cells to carboplatin-induced apoptosis demonstrating the importance of Mcl-1 downregulation in the apoptotic pathway mediated by the PBOX compounds in neuroblastoma. In conclusion, our findings indicate the potential of the PBOX compounds in enhancing chemosensitivity in neuroblastoma.
- Published
- 2014
71. Guanidinium-based derivatives: Searching for new kinase inhibitors
- Author
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Elena Diez-Cecilia, Isabel Rozas, Daniela M. Zisterer, Concepción Pérez, Brendan Kelly, David Lloyd, Daniel K. Nevin, Diez-Cecilia, E, Kelly, B, Perez, c, Zisterer, D M, Nevin, D K, Lloyd, David George, and Rozas, Isabel
- Subjects
MAPK/ERK pathway ,Models, Molecular ,Stereochemistry ,Cell Survival ,Antineoplastic Agents ,Apoptosis ,HL-60 Cells ,guanidine ,chemistry.chemical_compound ,Structure-Activity Relationship ,Protein kinases ,Cell Line, Tumor ,Drug Discovery ,Human Umbilical Vein Endothelial Cells ,Organometallic Compounds ,Humans ,Guanidine ,Cytotoxicity ,Protein kinase A ,Protein Kinase Inhibitors ,Cell Proliferation ,Pharmacology ,protein kinases ,RAF-1 ,biology ,Dose-Response Relationship, Drug ,Molecular Structure ,Kinase ,MEK-1 ,Organic Chemistry ,Phosphotransferases ,General Medicine ,Sorafenib ,Receptors, Vascular Endothelial Growth Factor ,chemistry ,Biochemistry ,Docking (molecular) ,docking ,Cancer cell ,biology.protein ,sorafenib ,Drug Screening Assays, Antitumor ,Platelet-derived growth factor receptor - Abstract
Considering the structural similarities between the kinase inhibitor sorafenib and 4,4′-bis-guanidinium derivatives previously prepared by Rozas and co., which display interesting cytotoxicity in cancer cells, we have studied whether this activity could result from kinase inhibition. Five new families have been prepared consisting of unsubstituted and aryl-substituted 3,4′-bis-guanidiniums, 3,4′-bis-2-aminoimidazolinium and 3-acetamide-4′-(4-chloro-3-trifluoromethylphenyl)guanidinium derivatives. Cytotoxicity (measuring the IC50 values) and apoptosis studies in human HL-60 promyelocytic leukemia cells were carried out for these compounds. Additionally, their potential inhibitory effect was explored on a panel of kinases known to be involved in apoptotic pathways. The previously prepared cytotoxic 4,4′-bis-guanidiniums did not inhibit any of these kinases; however, some of the novel 3,4′-substituted derivatives showed a high percentage inhibition of RAF-1/MEK-1, for which the potential mode of binding was evaluated by docking studies. The interesting antitumour properties showed by these compounds open up new exciting lines of investigation for kinase inhibitors as anticancer agents and also highlights the relevance of the guanidinium moiety for protein kinase inhibitors chemical design. © 2014 Elsevier Masson SAS. All rights reserved.
- Published
- 2014
72. Oxidative stress induces apoptosis in C6 glioma cells: Involvement of mitogen-activated protein kinases and nuclear factor kappa B
- Author
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Margaret M. McGee, D. Clive Williams, Daniela M. Zisterer, Keith F. Tipton, and Marina Marangolo
- Subjects
MAPK/ERK pathway ,Programmed cell death ,biology ,Apoptosis ,Kinase ,General Neuroscience ,Poly ADP ribose polymerase ,p38 mitogen-activated protein kinases ,biology.protein ,Toxicology ,Transcription factor ,Caspase ,Cell biology - Abstract
Excessive oxidative stress has been implicated in the induction of cell death in a variety of neurodegenerative diseases. In the present study, hydrogen peroxide (H2O2)-induced cell death in rat C6 glioma cells was used as a model system for studying the molecular events associated with oxidative stress-induced cell death in glial cells. We demonstrate that exposure of C6 glioma cells to H2O2 results in apoptotic cell death in a concentration-dependent manner, and caused activation of a member of the caspase-3-like family of proteases resulting in cleavage of the DNA repair enzyme poly(ADP-ribose)polymerase, PARP. Furthermore, H2O2 induced a transient activation of the transcription factor, nuclear factor kappa B (NF(Kappa)B). Pre-treatment of cells with the antioxidant N-acetylcysteine, (NAC), prevented both the activation of NF(Kappa)B and the induction of apoptosis by H2O2, suggesting a possible role for this transcription factor in oxidant-induced apoptosis in glial cells. Exposure of the cells to H2O2 led to transient activation of both c-Jun N-terminal kinase (JNK) and p38 kinase but has no effect on extracellular regulated kinase (ERK) activity. Inhibition of p38 by SB203580 did not protect the cells against H2O2-induced apoptosis suggesting that activation of p38 is not essential for H2O2-mediated cell death in C6 glioma cells.
- Published
- 2001
73. PBOX-15 induces apoptosis and improves the efficacy of oxaliplatin in human colorectal cancer cell lines
- Author
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Maurizio Bifulco, D. Clive Williams, Donatella Fiore, Patrizia Gazzerro, Daniela M. Zisterer, Alessia Ligresti, Chiara Laezza, Alice Casagni, Vincenzo Di Marzo, Giuseppe Campiani, Seema M. Nathwani, Sandra Gemma, Giuseppina Gangemi, Maria Proto, Mario Vitale, and Stefania Butini
- Subjects
Pharmacology ,Cell type ,Cell cycle checkpoint ,business.industry ,Cell ,Oxaliplatin ,medicine.anatomical_structure ,Apoptosis ,Fatty acid amide hydrolase ,Cell culture ,medicine ,Cancer research ,DNA fragmentation ,business ,medicine.drug - Abstract
An emerging new class of targeted therapeutic molecules against the enzyme fatty acid amide hydrolase (FAAH) is a novel series of pyrrolo-1,5-benzoxa(thia)zepine compounds. A member of this family, pyrrolo-1,5-benzoxazepine-15 (PBOX-15), is a tubulin depolymerizing agent displaying a proapoptotic activity in a variety of human tumor cell types, including those derived from both solid and hematological malignancies, with minimal toxicity towards normal blood and bone marrow cells. In this study, we evaluated the PBOX-15-mediated effects in human colorectal cancer cell (CRC) lines. The compound, used at doses equal to or greater than 1 μM inhibits the proliferation of human CRC cell lines in a dose- and time-dependent manner, inducing a significant cell cycle arrest in the G2/M phase. DNA fragmentation assays and western blot analysis demonstrated that treatments prolonged over 48 h triggered a strong activation of the intrinsic apoptotic pathway as indicated by activation of caspase-3, caspase-9 and PARP. Moreover, nanomolar doses of PBOX-15, unable to cause microtubule depolymerization, significantly improved the oxaliplatin and 5-fluouracil-induced anti-proliferative effects in CRC cell lines. These results showed, for the first time, that PBOX-15 represents a promising compound for the treatment of human CRC and a strong candidate for novel therapeutic options.
- Published
- 2013
74. The microtubule targeting agent PBOX-15 inhibits integrin-mediated cell adhesion and induces apoptosis in acute lymphoblastic leukaemia cells
- Author
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Mark Lawler, J Ryan, Paul Browne, Daniela M. Zisterer, D. Clive Williams, Navin Kumar Verma, Joanne Lysaght, Anthony M. McElligott, Giuseppe Campiani, and Elaina N. Maginn
- Subjects
Integrins ,Cancer Research ,Cell type ,Cell cycle checkpoint ,Blotting, Western ,Cell ,Integrin ,Fluorescent Antibody Technique ,Apoptosis ,Biology ,Microtubules ,Cell Movement ,Cell Adhesion ,Tumor Cells, Cultured ,medicine ,Humans ,Pyrroles ,Cell adhesion ,Cell Proliferation ,Cell growth ,Cell Cycle Checkpoints ,Precursor Cell Lymphoblastic Leukemia-Lymphoma ,Cell cycle ,Flow Cytometry ,Cell biology ,Oxazepines ,medicine.anatomical_structure ,Oncology ,biology.protein - Abstract
Although recent decades have seen an improved cure rate for newly diagnosed paediatric acute lymphoplastic leukaemia (ALL), the treatment options for adult ALL, T-cell ALL (T-ALL) and relapsed disease remain poor. We have developed a novel series of pyrrolo-1,5-benzoxazepine (PBOX) compounds and established their anticancer efficacy in a variety of human tumour cell types. Here, we demonstrate that PBOX-15 inhibits cell growth, and induces G2/M cell cycle arrest and apoptosis in both T-ALL and B-cell ALL (B-ALL) cells. In addition, prior to PBOX-15-induced apoptosis, PBOX-15 decreases ALL cell adhesion, spreading and migration. Concurrently, PBOX-15 differentially down-regulates β1-, β2- and α4-integrin expression in ALL cells and significantly decreases integrin-mediated cell attachment. PBOX-15 interferes with the lateral mobility and clustering of integrins in both B-ALL and T-ALL cells. These data suggest that PBOX-15 is not only effective in inducing apoptosis in ALL cells, but also has the potential to disrupt integrin-mediated adhesion of malignant lymphocytes, which represents a novel avenue for regulating leukaemic cell homing and migration.
- Published
- 2013
75. Hexachlorocyclohexanes inhibit steroidogenesis in Y1 cells
- Author
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D. Clive Williams, Daniela M. Zisterer, and Paul N. Moynagh
- Subjects
Pharmacology ,chemistry.chemical_classification ,Chemistry ,Adrenal cortex ,medicine.medical_treatment ,Cholesterol side-chain cleavage enzyme ,Biochemistry ,In vitro ,Steroid ,Enzyme ,medicine.anatomical_structure ,Mechanism of action ,Cell culture ,medicine ,Pregnenolone ,medicine.symptom ,medicine.drug - Abstract
Lindane, the γ-isomer of hexachlorocyclohexane (HCH), and two other HCH-isomers, α and δ-HCH, inhibit steroidogenesis in a Y1 adrenocortical cell line. In determining the mechanism by which HCH isomers inhibit steroidogenesis, they were found not to act directly on the mitochondrial Cyt P-450scc enzyme, making it likely that they act, instead, on intramitochondrial transport of cholesterol. γ-HCH, but not α or δ-HCH, is a potent and selective inhibitor of ligand binding to the peripheral-type benzodiazepine binding site (PBBS) which, in turn, is reported to regulate the rate-limiting step in steroidogenesis. Although these results demonstrate that α and δ-HCH do not inhibit steroid production through the PBBS, the possibility that the interaction of γ-HCH with the PBBS is responsible for its inhibitory effect on steroidogenesis could not be excluded.
- Published
- 1996
76. Design, Synthesis and Biochemical Evaluation of Novel Selective Estrogen Receptor Ligand Conjugates Incorporating an Endoxifen-Combretastatin Hybrid Scaffold
- Author
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Bassem Yassin, Mary J. Meegan, David Lloyd, Gloria Ana, Niall O. Keely, Miriam Carr, Daniela M. Zisterer, Keely, Niall O, Carr, Miriam, Yassin, Bassem, Ana, Gloria, Lloyd, David G, Zisterer, Daniela, and Meegan, Mary J
- Subjects
conjugates ,0301 basic medicine ,Medicine (miscellaneous) ,Estrogen receptor ,Pharmacology ,Article ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,estrogen receptor ligands ,selective estrogen receptor modulators ,tumour targeting ,tamoxifen ,endoxifen ,hormone-dependent breast cancer ,medicine ,Pharmacology & Pharmacy ,Cytotoxicity ,lcsh:QH301-705.5 ,Combretastatin ,Chemistry ,Ligand (biochemistry) ,030104 developmental biology ,lcsh:Biology (General) ,Biochemistry ,Cell culture ,Selective estrogen receptor modulator ,030220 oncology & carcinogenesis ,Tamoxifen ,Conjugate ,medicine.drug - Abstract
Nuclear-receptors are often overexpressed in tumours and can thereby be used as targets when designing novel selective chemotherapeutic agents. To date, many conjugates incorporating an estrogen receptor (ER) ligand have been synthesised in order to direct chemical agents to tissue sites containing ERs. A series of ER ligand conjugates were synthesised incorporating an antagonistic ER ligand scaffold based on endoxifen, covalently-bound via an amide linkage to a variety of combretastatin-based analogues, which may act as antimitotic agents. These novel endoxifen-combretastatin hybrid scaffold analogues were biochemically evaluated in order to determine their antiproliferative and cytotoxicity effects in both the ER-positive MCF-7 and the ER-negative MDA-MB-231 human breast cancer cell lines. ER competitive binding assays were carried out to assess the binding affinity of the lead conjugate 28 towards both the ER alpha and ER beta isoforms. In results from the NCI 60-cell line screen, the lead conjugate 28 displayed potent and highly selective antiproliferative activity towards the MCF-7 human cancer cell line (IC50 = 5 nM). In the ER-binding assays, the lead conjugate 28 demonstrated potent ER competitive binding in ER alpha (IC50 value: 0.9 nM) and ER beta (IC50 value: 4.7 nM). Preliminary biochemical results also demonstrate that the lead conjugate 28 may exhibit pure antagonism. This series makes an important addition to the class of ER antagonists and may have potential applications in anticancer therapy. Refereed/Peer-reviewed
- Published
- 2016
77. Synthesis and biochemical activities of antiproliferative amino acid and phosphate derivatives of microtubule-disrupting β-lactam combretastatins
- Author
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Mary J. Meegan, Niamh M. O’Boyle, Daniela M. Zisterer, Shu Wang, Tadhg S. Cotter, Niall O. Keely, and Lisa M. Greene
- Subjects
Models, Molecular ,Stereochemistry ,Antineoplastic Agents ,Biochemistry ,Microtubules ,Tubulin binding ,Phosphates ,chemistry.chemical_compound ,Structure-Activity Relationship ,Heterocyclic Compounds ,Microtubule ,Drug Discovery ,Stilbenes ,Structure–activity relationship ,Humans ,Organic Chemicals ,Amino Acids ,Cell Proliferation ,Pharmacology ,Combretastatin A-4 ,Combretastatin ,chemistry.chemical_classification ,biology ,Dose-Response Relationship, Drug ,Molecular Structure ,solubility ,Organic Chemistry ,combretastatin A-4 prodrug ,General Medicine ,In vitro ,Amino acid ,Medicinal Chemistry and Pharmaceutics ,Tubulin ,tubulin ,Pharmaceutical Preparations ,chemistry ,Solubility ,biology.protein ,MCF-7 Cells ,Amino Acids, Peptides, and Proteins ,Antiproliferative ,beta-lactam ,Other Chemicals and Drugs - Abstract
The synthesis and biochemical activities of novel water-soluble β-lactam analogues of combretastatin A-4 are described. The first series of compounds investigated, β-lactam phosphate esters 7a, 8a and 9a, exhibited potent antiproliferative activity and caused microtubule disruption in human breast carcinoma-derived MCF-7 cells. They did not inhibit tubulin polymerisation in vitro, indicating that biotransformation was necessary for their antiproliferative and tubulin binding effects in MCF-7 cells. The second series of compounds, β-lactam amino acid amides (including 10k and 11l) displayed potent antiproliferative activity in MCF-7 cells, disrupted microtubules in MCF-7 cells and also inhibited the polymerisation of tubulin in vitro. This indicates that the β-lactam amides did not require metabolic activation to have antiproliferative effects, in contrast to the phosphate series. Both series of compounds caused mitotic catastrophe and apoptosis in MCF-7 cells. Molecular modelling studies indicated potential binding conformations for the β-lactam amino acid amides 10k and 11l in the colchicine-binding site of tubulin. Due to their aqueous solubility and potent biochemical effects, these compounds are promising candidates for further development as microtubule-disrupting agents.
- Published
- 2012
78. Combretazet-3 a novel synthetic cis-stable combretastatin A-4-azetidinone hybrid with enhanced stability and therapeutic efficacy in colon cancer
- Author
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Jane E. A. Reid, Sandra A. Bright, Lisa M. Greene, Daniela M. Zisterer, Mary J. Meegan, Niamh M. O’Boyle, Patrick Kelly, and Shu Wang
- Subjects
Cancer Research ,Cell Survival ,Cell ,Pharmacology, Toxicology and Environmental Health ,Mice, Nude ,Antineoplastic Agents ,Biology ,Pharmacology ,Biochemistry ,microtubules ,chemistry.chemical_compound ,Inhibitory Concentration 50 ,Mice ,Drug Stability ,Cell Line, Tumor ,medicine ,Autophagy ,Animals ,Humans ,Molecular Biology ,Combretastatin ,Combretastatin A-4 ,Mice, Inbred BALB C ,Aryl ,beta-lactams ,Guaiacol ,Cancer ,General Medicine ,azetidinones ,Cell cycle ,Hydrogen-Ion Concentration ,medicine.disease ,Xenograft Model Antitumor Assays ,Tumor Burden ,G2 Phase Cell Cycle Checkpoints ,medicine.anatomical_structure ,Oncology ,chemistry ,colon cancer ,Colonic Neoplasms ,Microsomes, Liver ,Azetidines ,Chemical stability ,Female ,Lead compound ,Injections, Intraperitoneal - Abstract
In recent years an extensive series of synthetic combretastatin A-4 (CA-4)-azetidinone (β-lactam) hybrids were designed and synthesised with a view to improve the stability, therapeutic efficacy and aqueous solubility of CA-4. Lead compounds containing a 3,4,5-trimethoxy aromatic ring at position 1 and a variety of substitution patterns at positions 3 and 4 of the β-lactam ring were screened in three adenocarcinoma-derived colon cancer cell lines (CT-26, Caco-2 and the CA-4 resistant cell line, HT-29). In both CT-26 and Caco-2 cells all β-lactam analogues analysed displayed potent therapeutic efficacy within the nanomolar range. Substitution of the ethylene bridge of CA-4 with the β-lactam ring together with the aforementioned aryl substitutions improved the therapeutic efficacy of CA-4 up to 300‑fold in the combretastatin refractory HT-29 cells. The lead compound combretazet-3 (CAZ-3); chemical name [4-(3-hydroxy-4-methoxyphenyl)-3-(4-hydroxyphenyl)-1-(3,4,5-trimethoxyphenyl)azetidin-2-one] demonstrated improved chemical stability together with enhanced therapeutic efficacy as compared with CA-4 whilst maintaining the natural biological properties of CA-4. Furthermore, CAZ-3 demonstrated significant tumour inhibition in a murine model of colon cancer. Our results suggest that combretastatin-azetidinone hybrids represent an effective novel therapy for the treatment of combretastatin resistant carcinomas.
- Published
- 2012
79. Treatment of Chronic Myeloid Leukaemia: Current Practice and Future Prospects
- Author
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Daniela M. Zisterer
- Subjects
Myeloid ,medicine.drug_class ,business.industry ,Imatinib ,Philadelphia chromosome ,medicine.disease ,Tyrosine-kinase inhibitor ,Haematopoiesis ,Imatinib mesylate ,medicine.anatomical_structure ,hemic and lymphatic diseases ,medicine ,Cancer research ,business ,Protein kinase B ,Tyrosine kinase ,medicine.drug - Abstract
Chronic myeloid leukaemia (CML) is a cancer of the hematopoietic system that arises from the Philadelphia chromosome (Ph1). This results from the reciprocal translocation of chromosomes 9 and 22 which generates a Bcr-Abl fusion gene encoding a 210kDa protein with constitutive tyrosine kinase activity (Ben-Neriah et al., 1986; Kuzrock et al., 1988). This constitutively active tyrosine kinase drives proliferation and survival through multiple downstream pathways (Reviewed in Cowan-Jacob et al., 2004; Ren et al., 2005). The disease is characterised by three stages; the chronic phase marked by an accumulation of mature granulocytes and myeloid precursors in the bone marrow and peripheral blood; the accelerated phase characterised by a rise in myeloid precursors and a blast crisis stage which is characterised by a marked accumulation of differentiation-arrested blast cells of either myeloid or lymphoid lineage (Calabretta & Perotti, 2004; Savage et al., 1997). The generation and clinical use of the Bcr-Abl tyrosine kinase inhibitor (TKI) imatinib mesylate (IM) has revolutionised the treatment of CML patients (Druker et al., 1996; Druker et al., 2006) and has become the standard line of therapy for CML patients. Following treatment with imatinib, over 90% of patients obtain a complete haematologic response and more than 80% achieve a complete cytogenetic response. However, there are limitations associated with IM therapy. The drug is highly effective in the chronic phase of the disease but the response of patients in blast crisis is limited (Hehlman & Saussele, 2008). Furthermore, in approximately 40% of patients, resistance develops i.e. resistance in 100 patient years (Gorre et al., 2001). Great progress has been made over the last ten years in elucidating the molecular mechanisms of IM-resistance in vitro but correlating any of these individual resistance mechanisms in a clinical sample does not always indicate that it alone drives clinical progression as additional modes of resistance may be at work. The mechanisms by which patients become resistant to IM therapy include Bcr-Abl dependent mechanisms such as an increase in the levels of Bcr-Abl mRNA expression and corresponding upregulation of protein levels and amplification of the Bcr-Abl gene (Mahon et al. 2000). Bcr-Abl independent mechanisms include activation of signalling pathways downstream of Bcr-Abl including the phosphatidylinositol 3-kinase (PI3K)/Akt cell survival pathway or activation of signalling pathways separate to that of the Bcr-Abl gene and an efflux of IM via multidrug resistant proteins such as p-glycoprotein (Capdeville et al., 2002). The most well-characterised cooperating pathway involves the Src Family Kinases (SFKs) which have
- Published
- 2012
80. ChemInform Abstract: Synthesis, Biochemical and Molecular Modeling Studies of Antiproliferative Azetidinones Causing Microtubule Disruption and Mitotic Catastrophe
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Miriam Carr, Daniela M. Zisterer, Mary J. Meegan, Niamh M. O’Boyle, Thomas McCabe, David Lloyd, Lisa M. Greene, Andrew J. S. Knox, and Niall O. Keely
- Subjects
Molecular model ,Microtubule ,Chemistry ,Biophysics ,General Medicine ,Reformatsky reaction ,Mitotic catastrophe - Abstract
A series of azetidinones of type (III), (II), and (XI) is prepared using the Staudinger and (VI) using Reformatsky reaction.
- Published
- 2011
81. BubR1 is required for the mitotic block induced by combretastatin-A4 and a novel cis-restricted ß-lactam analogue in human cancer cells
- Author
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Mary J. Meegan, Mark Lawler, Lisa M. Greene, Niall O. Keeley, Miriam Carr, and Daniela M. Zisterer
- Subjects
Cell cycle checkpoint ,Poly (ADP-Ribose) Polymerase-1 ,Mitosis ,Apoptosis ,Protein Serine-Threonine Kinases ,chemistry.chemical_compound ,Tubulin ,Microtubule ,Cell Line, Tumor ,Stilbenes ,Genetics ,Humans ,Phosphorylation ,Combretastatin ,biology ,Caspase 3 ,Cell Cycle ,Guaiacol ,General Medicine ,Cell cycle ,Mitotic spindle checkpoint ,Antineoplastic Agents, Phytogenic ,Molecular biology ,Cell biology ,Spindle apparatus ,chemistry ,biology.protein ,Azetidines ,RNA Interference ,Poly(ADP-ribose) Polymerases ,Protein Multimerization - Abstract
BubR1 is a well-defined guardian of the mitotic spindle, initiating mitotic arrest in response to the lack of tension and/or chromosome alignment across the mitotic plate. However, the role of BubR1 in combretastatin-induced cell death remains unknown. In this study, we describe the effects of combretastatin A-4 (CA-4) and a synthetic cis-restricted 3,4-diaryl-2-azetidinone (ß-lactam) analogue (CA-432) on the modulation and phosphorylation of BubR1 in human cervical cancer-derived cells. We demonstrate that CA-4 and CA-432 depolymerise the microtubular network of human cervical carcinoma-derived cells. Both compounds induced the disassembly of the microtubules and the loss of microtubule tension led to the early phosphorylation of BubR1 and the late cleavage of BubR1. The phosphorylation of BubR1 correlated with the onset of G2M cell cycle arrest whilst the cleavage of BubR1 coincided with apoptosis induced by the combretastatins. The combretastatin-induced apoptosis and the BubR1 cleavage were caspase-dependent. In vitro enzyme digests demonstrated that combretastatin-activated BubR1 is a substrate for caspase-3. Gene silencing of BubR1 with small interfering RNA severely compromised combretastatin-induced G2M cell cycle arrest with a corresponding increase in the formation of polyploid cells in both cervical and breast cancer-derived cells. In summary, BubR1 is required to maintain the G2M arrest and limit the formation of polyploid cells in response to continued combretastatin exposure. Moreover, substitution of the ethylene bridge with 3,4-diaryl-2-azetidinone did not alter the tubulin depolymerising properties or the subsequent mitotic spindle checkpoint response to CA-4 in human cancer cells.
- Published
- 2011
82. Microtubule targeting compound PBOX 15 radiosensitizes cancer cells in vitro
- Author
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D. Clive Williams, Mark Lawler, Gillian McNamara, Elaina N. Maginn, Guiseppe Campiani, Thomas H. Lynch, Lynn Martin, James C. Forde, Anthony M. McElligott, Laure Marignol, Donal Hollywood, and Daniela M. Zisterer
- Subjects
Male ,Cancer Research ,Radiation-Sensitizing Agents ,Apoptosis ,Biology ,Microtubules ,Radiation Tolerance ,Radioresistance ,Cell Line, Tumor ,Neoplasms ,medicine ,Humans ,Pyrroles ,Radiosensitivity ,Hypoxia ,Pharmacology ,Cell Cycle ,Cell cycle ,Hypoxia (medical) ,Hypoxia-Inducible Factor 1, alpha Subunit ,In vitro ,Aerobiosis ,Cell biology ,Gene Expression Regulation, Neoplastic ,Oxazepines ,Oncology ,Cell culture ,Cancer cell ,Cancer research ,Molecular Medicine ,medicine.symptom - Abstract
We proposed to investigate the radiosensitizing properties of PBOX-15, a novel microtubule-disrupting agent, in a panel of cancer cell lines.PBOX-15 treatment was associated with significant cell kill and increased radiosensitivity in all three cell lines tested. The number of surviving cells in response to the combined treatment was significantly less than PBOX -15 alone in 22Rv1 cells. In these cells, radiosensitisation correlated with induction of G2/M cell cycle arrest by PBOX-15. The compound sustained its activity and increased HIF-1Α expression under hypoxic conditions. PBOX-15 prevented onset of hypoxia-induced radioresistance in hypoxic prostate cells and reduced the surviving fraction of irradiated hypoxic cells to levels similar to those achieved under aerobic conditions.Clonogenic assays were used to determine sensitivity of a panel of cancer cell lines (22Rv1, A549, U87) to PBOX-15 alone or in combination with a single 2Gy dose fraction. Induction of cell cycle arrest and apoptosis was investigated in 22Rv1 prostate cancer cells. The cytotoxic properties of the compound under hypoxic conditions were correlated with Hypoxia Inducible Factor 1 alpha (HIF-1Α) gene and protein expression levels and its radiosensitisation potential was investigated in hypoxic 22Rv1 using clonogenic assays.This preliminary data identifies the potential of PBOX-15 as a novel radiosensitising agent for the management of solid tumours and eradication of hypoxic cells.
- Published
- 2011
83. PBOX-15, a novel microtubule targeting agent, induces apoptosis, upregulates death receptors, and potentiates TRAIL-mediated apoptosis in multiple myeloma cells
- Author
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Paul Browne, Patrick Hayden, Giuseppe Campiani, Mark Lawler, P Evans, B MacDonagh, Stefania Butini, Elaina N. Maginn, Elisabeth Vandenberghe, Prerna Tewari, Daniela M. Zisterer, M Goodyer, Anthony M. McElligott, and D. C. Williams
- Subjects
Cancer Research ,Programmed cell death ,Down-Regulation ,Apoptosis ,TRAIL ,Biology ,Caspase 8 ,Microtubules ,caspase-8 ,TNF-Related Apoptosis-Inducing Ligand ,Downregulation and upregulation ,Cell Line, Tumor ,Humans ,Pyrroles ,DR5 ,Receptor ,Receptors, Death Domain ,Cell cycle ,Up-Regulation ,Oxazepines ,myeloma ,Oncology ,Microscopy, Fluorescence ,Cell culture ,Immunology ,Cancer cell ,Cancer research ,bim ,Multiple Myeloma ,Translational Therapeutics - Abstract
Background: In recent years, much progress has been made in the treatment of multiple myeloma. However, a major limitation of existing chemotherapeutic drugs is the eventual emergence of resistance; hence, the development of novel agents with new mechanisms of action is pertinent. Here, we describe the activity and mechanism of action of pyrrolo-1,5-benzoxazepine-15 (PBOX-15), a novel microtubule-targeting agent, in multiple myeloma cells. Methods: The anti-myeloma activity of PBOX-15 was assessed using NCI-H929, KMS11, RPMI8226, and U266 cell lines, and primary myeloma cells. Cell cycle distribution, apoptosis, cytochrome c release, and mitochondrial inner membrane depolarisation were analysed by flow cytometry; gene expression analysis was carried out using TaqMan Low Density Arrays; and expression of caspase-8 and Bcl-2 family of proteins was assessed by western blot analysis. Results: Pyrrolo-1,5-benzoxazepine-15 induced apoptosis in ex vivo myeloma cells and in myeloma cell lines. Death receptor genes were upregulated in both NCI-H929 and U266 cell lines, which displayed the highest and lowest apoptotic responses, respectively, following treatment with PBOX-15. The largest increase was detected for the death receptor 5 (DR5) gene, and cotreatment of both cell lines with tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), the DR5 ligand, potentiated the apoptotic response. In NCI-H929 cells, PBOX-15-induced apoptosis was shown to be caspase-8 dependent, with independent activation of extrinsic and intrinsic apoptotic pathways. A caspase-8-dependent decrease in expression of BimEL preceded downregulation of other Bcl-2 proteins (Bid, Bcl-2, Mcl-1) in PBOX-15-treated NCI-H929 cells. Conclusion: PBOX-15 induces apoptosis and potentiates TRAIL-induced cell death in multiple myeloma cells. Thus, PBOX-15 represents a promising agent, with a distinct mechanism of action, for the treatment of this malignancy.
- Published
- 2010
84. Novel microtubule-targeting agents, pyrrolo-1,5-benzoxazepines, induce cell cycle arrest and apoptosis in prostate cancer cells
- Author
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Suzanne M. Cloonan, Seema-Maria Nathwani, D. Clive Williams, Giuseppe Campiani, Daniela M. Zisterer, Maeve Stronach, and Mark Lawler
- Subjects
Male ,Cancer Research ,Programmed cell death ,medicine.medical_specialty ,Cell cycle checkpoint ,Drug Evaluation, Preclinical ,Antineoplastic Agents ,Apoptosis ,Adenocarcinoma ,Biology ,Models, Biological ,Inhibitory Concentration 50 ,Prostate cancer ,Cell Line, Tumor ,Internal medicine ,medicine ,Humans ,Pyrroles ,Mitosis ,Cell Proliferation ,Dose-Response Relationship, Drug ,Cell growth ,Cell Cycle ,Prostatic Neoplasms ,Cancer ,General Medicine ,Cell cycle ,medicine.disease ,Mitotic spindle checkpoint ,Tubulin Modulators ,Oxazepines ,Endocrinology ,Oncology ,Cancer research - Abstract
Advanced hormone-refractory prostate cancer is associated with poor prognosis and limited treatment options. Members of the pyrrolo-1,5-benzoxazepine (PBOX) family of compounds exhibit anti-cancer properties in cancer cell lines (including multi-drug resistant cells), ex vivo patient samples and in vivo mouse tumour models with minimal toxicity to normal cells. Recently, they have also been found to possess anti-angiogenic properties in vitro. However, both the apoptotic pathways and the overall extent of the apoptotic response induced by PBOX compounds tend to be cell-type specific. Since the effect of the PBOX compounds on prostate cancer has not yet been elucidated, the purpose of this study was to investigate if PBOX compounds induce anti-proliferative effects on hormone-refractory prostate cancer cells. We examined the effect of two representative PBOX compounds, PBOX-6 and PBOX-15, on the androgen-independent human prostate adenocarcinoma cell line, PC3. PBOX-6 and -15 displayed anti-proliferative effects on PC3 cells, mediated initially through a sustained G2/M arrest. G2/M arrest, illustrated as DNA tetraploidy, was accompanied by microtubule depolymerisation and phosphorylation of anti-apoptotic proteins Bcl-2 and Bcl-xL and the mitotic spindle checkpoint protein BubR1. Phosphorylation of BubR1 is indicative of an active mitotic checkpoint and results in maintenance of cell cycle arrest. G2/M arrest was followed by apoptosis illustrated by DNA hypoploidy and PARP cleavage and was accompanied by degradation of BubR1, Bcl-2 and Bcl-xL. Furthermore, sequential treatment with the CDK1-inhibitor, flavopiridol, synergistically enhanced PBOX-induced apoptosis. In summary, this in vitro study indicates that PBOX compounds may be useful alone or in combination with other agents in the treatment of hormone-refractory prostate cancer.
- Published
- 2010
85. ChemInform Abstract: Synthesis, Biological Activity, and SARs of Pyrrolobenzoxazepine Derivatives, a New Class of Specific 'Peripheral-Type' Benzodiazepine Receptor Ligands
- Author
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Antonio Garofalo, Ettore Novellino, Isabella Fiorini, Vito Nacci, Daniela M. Zisterer, Cristina Manzoni, C. Mihai, Giovanni Greco, Margaret J. Woods, S. M. Ciani, Giuseppe Campiani, Tiziana Mennini, D. C. Williams, and M. P. De Filippis
- Subjects
PK-11195 ,chemistry.chemical_compound ,Molecular model ,Stereochemistry ,Chemistry ,Potency ,Biological activity ,General Medicine ,Mitochondrion ,Receptor ,IC50 ,Affinities - Abstract
The "peripheral-type" benzodiazepine receptor (PBR) has been reported to play a role in many biological processes. We have synthesized and tested a novel series of PBR ligands based on a pyrrolobenzoxazepine skeleton, in order to provide new receptor ligands. Several of these new compounds proved to be high affinity and selective ligands for PBR, and benzoxazepines 17f and 17j were found to be the most potent ligands for this receptor to have been identified to date. The SAR and the molecular modeling studies detailed herein delineated a number of structural features required for improving affinity. Some of the ligands were employed as "molecular yardsticks" to probe the spatial dimensions of the lipophilic pockets L1 and L3 in the PBR cleft and to determine the effect of occupation of L1 and L3 with respect to affinity, while other C-7 modified analogues provided information specifically on the hydrogen bonding with a putative receptor site H1. The new pyrrolobenzoxazepines were tested in rat cortex, a tissue expressing high density of mitochondrial PBR, and exhibited IC50 and Ki values in the low nanomolar or subnanomolar range, as measured by the displacement of [3H]PK 11195 binding. A subset of the highest affinity ligands was also found to have high affinities for [3H]PK 11195 and [3H]Ro 5-4864 binding in rat adrenal mitochondria. All the ligands in this subset are stimulators of steroidogenesis having similar potency and extent of stimulation as PK 11195 and Ro 5-4864 of steroidogenesis in the mouse Y-1 adrenocortical cell line.
- Published
- 2010
86. ChemInform Abstract: Flexible Estrogen Receptor Modulators: Design, Synthesis, and Antagonistic Effects in Human MCF-7 Breast Cancer Cells
- Author
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Mary J. Meegan, Rosario B. Hughes, Daniela M. Zisterer, David Lloyd, and D. Clive Williams
- Subjects
Chemistry ,Aryl ,Estrogen receptor ,General Medicine ,Pharmacology ,Estrogen Receptor Antagonists ,chemistry.chemical_compound ,MCF-7 ,medicine ,Moiety ,Potency ,skin and connective tissue diseases ,Cytotoxicity ,Tamoxifen ,medicine.drug - Abstract
Although many series of estrogen receptor antagonists continue to be produced, the majority are direct structural analogues of existing modulators. To examine the tolerance of the estrogen receptor toward flexible ligands, a series of novel flexible estrogen receptor antagonists were prepared and their antiproliferative effects on human MCF-7 breast tumor cells investigated. Each of these compounds deviated from the traditional triphenylethylene backbone associated with common tamoxifen analogues through the introduction of a flexible methylene (benzylic) spacing group between one of the aryl rings and the ethylene group and through variations in the basic side chain moiety. The compounds prepared, when assayed in conjunction with a tamoxifen standard, demonstrated high potency in antiproliferative assays against an MCF-7 human breast cancer cell line with low cytotoxicity and high binding affinity. A computational study was undertaken to investigate the compounds' potential interactions with specific res...
- Published
- 2010
87. Novel microtubule-targeting agents, pyrrolo-1,5-benzoxazepines, induce apoptosis in multi-drug-resistant cancer cells
- Author
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Stephen Butler, Balázs Sarkadi, David Lloyd, Daniela M. Zisterer, D. Clive Williams, Giuseppe Campiani, Darren Fayne, Mary J. Meegan, Seema-Maria Nathwani, Mark Lawler, Naomi McGovern, School of Biochemistry and Immunology, Trinity College Dublin, School of Pharmacy and Pharmaceutical Sciences, Molecular Design Group, School of Biochemistry and Immunology, Membrane Research Group of Hungarian Academy of Sciences, Semmelweis University and National Blood Center, European Research Centre for Drug Discovery and Development, Banchi di Sotto 55 and Dipartimento Farmaco Chimico Tecnologico, Università degli Studi di Siena = University of Siena (UNISI), Institute of Molecular Medicine, St. James's Hospital and Trinity College, Nathwani, Seema-Maria, Butler, Stephen, Fayne, Darren, McGovern, Naomi N, Sarkadi, Balazs, Meegan, Mary J, Lloyd, David G, Campiani, Giuseppe, Lawler, Mark, Williams, D Clive, and Zisterer, Daniela M
- Subjects
Cancer Research ,Abcg2 ,ATP-binding cassette transporter ,Apoptosis ,Pharmacology ,Toxicology ,Microtubules ,0302 clinical medicine ,Neoplasms ,ATP Binding Cassette Transporter, Subfamily G, Member 2 ,Pharmacology (medical) ,multi-drug resistance (MDR) ,ComputingMilieux_MISCELLANEOUS ,P-glycoprotein ,Multi-drug resistance (MDR) ,0303 health sciences ,biology ,Cell Cycle ,Cell cycle ,Drug Resistance, Multiple ,Tubulin Modulators ,3. Good health ,Neoplasm Proteins ,Oncology ,030220 oncology & carcinogenesis ,BCRP ,Efflux ,Programmed cell death ,Antineoplastic Agents ,HL-60 Cells ,03 medical and health sciences ,PBOX ,Cell Line, Tumor ,Humans ,Pyrroles ,ATP Binding Cassette Transporter, Subfamily B, Member 1 ,030304 developmental biology ,Cell Proliferation ,Cell growth ,Microtubule-targeting agents ,microtubule-targeting agents ,Benzazepines ,Oxazepines ,Drug Resistance, Neoplasm ,Cancer cell ,Cancer research ,biology.protein ,ATP-Binding Cassette Transporters ,Carbamates - Abstract
Purpose : The development of multi-drug resistance (MDR) due to the expression of members of the ATP binding cassette (ABC) transporter family is a major obstacle in cancer treatment. The broad range of substrate speciWcities associated with these transporters leads to the eZux of many anti-cancer drugs from tumour cells. Therefore, the development of new chemotherapeutic agents that are not substrates of these transporters is important. We have recently demonstrated that some members of a novel series of pyrrolo-1,5-benzoxazepine (PBOX) compounds are microtubule-depolymerising agents that potently induce apoptosis in several cancer cell lines and impair growth of mouse breast tumours. The aim of this current study was to establish whether PBOXs were capable of inducing apoptosis in cancer cells expressing either P-glycoprotein or breast cancer resistance protein (BCRP), two of the main ABC transporters associated with MDR. Methods : We performed in vitro studies to assess the eVects of PBOXs on cell proliferation, cell cycle and apoptosis in human cancer cell lines and their drug-resistant substrains expressing either P-glycoprotein or BCRP. In addition, we performed a preliminary molecular docking study to examine interactions between PBOXs and P-glycoprotein. Results : We established that three representative PBOXs, PBOX-6, -15 and -16 were capable of inducing apoptosis in drug-resistant HL60-MDR1 cells (expressing P-glycoprotein) and HL60-ABCG2 cells (expressing BCRP) with similar potencies as in parental human promyelocytic leukaemia HL60 cells. Likewise, resistance to PBOX-6 and -16 was not evident in P-glycoprotein-expressing A2780-ADR cells in comparison with parent human ovarian carcinoma A2780 cells. Finally, we deduced by molecular docking that PBOX-6 is not likely to form favourable interactions with the substrate binding site of P-glycoprotein. Conclusion : Our results suggest that pro-apoptotic PBOX compounds may be potential candidates for the treatment of P-glycoprotein- or BCRP-associated MDR cancers.
- Published
- 2010
88. Lead identification of conformationally restricted benzoxepin type combretastatin analogs : synthesis, antiproliferative activity, and tubulin effects
- Author
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Irene Barrett, David Lloyd, Mary J. Meegan, Andrew J. S. Knox, Lisa M. Greene, Miriam Carr, Daniela M. Zisterer, Niamh M. O’Boyle, Barrett, I, Carr, M, O'Boyle, NM, Greene, LM, Knox, AJS, Lloyd, David George, Zisterer, DM, and Meegan, MJ
- Subjects
Models, Molecular ,antiproliferative activity ,Stereochemistry ,Breast Neoplasms ,chemistry.chemical_compound ,Structure-Activity Relationship ,Breast cancer cell line ,Tubulin ,Benzoxepin ,Carcinoma Cell ,Cell Line, Tumor ,Drug Discovery ,Stilbenes ,benzoxepin ,combretastatin analogs ,Benzoxepins ,Humans ,skin and connective tissue diseases ,Cell Proliferation ,Pharmacology ,Combretastatin ,Binding Sites ,biology ,Molecular Structure ,Chemistry ,General Medicine ,Antineoplastic Agents, Phytogenic ,Drug Design ,biology.protein ,Female ,Human breast ,Protein Binding - Abstract
We have synthesized a series of polymethoxylated rigid analogs of combretastatin A-4 which contain a benzoxepin ring in place of the usual ethylene bridge present in the natural combretastatin products. The compounds display antiproliferative activity when evaluated against the MCF-7 and MDA human breast carcinoma cell lines. 5-(3-Hydroxy-4-methoxyphenyl)-4-(3,4,5-trimethoxyphenyl)-2,3-dihydro-benzoxepine (11g) was found to be the most potent product when evaluated against the MCF-7 breast cancer cell line. A brief computational study of the structure-activity relationship for the synthesized compounds is presented. These 4,5-diarylbenzoxepins are identified as potentially useful scaffolds for the further development of antitumor agents which target tubulin. Refereed/Peer-reviewed
- Published
- 2010
89. Lead identification of conformationally restricted β-lactam type combretastatin analogues : synthesis, antiproliferative activity and tubulin targeting effects
- Author
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Miriam Carr, Daniela M. Zisterer, David Lloyd, Mary J. Meegan, Lisa M. Greene, Andrew J. S. Knox, Carr, M, Greene, LM, Knox, AJS, Lloyd, David George, Zisterer, DM, and Meegan, MJ
- Subjects
Models, Molecular ,structure-activity ,Stereochemistry ,β-lactam ,Molecular Conformation ,Antineoplastic Agents ,beta-Lactams ,01 natural sciences ,Chemical synthesis ,Structure-Activity Relationship ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Tubulin ,Cell Line, Tumor ,Stilbenes ,Drug Discovery ,Animals ,Humans ,Computer Simulation ,Cytotoxicity ,Cell Proliferation ,Pharmacology ,Combretastatin ,Cell Death ,Dose-Response Relationship, Drug ,biology ,010405 organic chemistry ,Cell Cycle ,Organic Chemistry ,Stereoisomerism ,General Medicine ,Cell cycle ,In vitro ,0104 chemical sciences ,3. Good health ,chemistry ,Biochemistry ,tubulin ,Cell culture ,030220 oncology & carcinogenesis ,biology.protein ,Lactam ,cytotoxicity ,Cattle ,2-azetidinon ,Drug Screening Assays, Antitumor ,combrestatin A-4 analogues - Abstract
The synthesis and study of the structureeactivity relationships of a series of rigid analogues of combretastatin A-4 are described which contain the 1,4-diaryl-2-azetidinone (β-lactam) ring system in place of the usual ethylene bridge present in the natural combretastatin stilbene products. The 1,4-diaryl-2-azetidinones are unsubstituted at C-3, or contain methyl substituent(s) at C-3. The most potent compounds 12d and 12e display antiproliferative activity at nanomolar concentrations when evaluated against the MCF-7 and MDA-MB-231 human breast carcinoma cell lines. 12d exerts antimitotic effects through an inhibition of tubulin polymerisation and subsequent G2/M arrest of the cell cycle in human MDA-MB-231 breast cancer cells, with similar activity to that of CA-4. These novel β-lactam compounds are identified as potentially useful scaffolds for the further development of antitumour agents which target tubulin. Refereed/Peer-reviewed
- Published
- 2010
90. Dual targeting of tumour cells and host endothelial cells by novel microtubule-targeting agents, pyrrolo-1,5-benzoxazepines
- Author
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Seema-Maria Nathwani, Mary J. Meegan, Mark Lawler, Stephen Butler, Daniela M. Zisterer, D. Clive Williams, and Giuseppe Campiani
- Subjects
Cancer Research ,Pathology ,medicine.medical_specialty ,Cell type ,Umbilical Veins ,Angiogenesis ,Cellular differentiation ,Antineoplastic Agents ,Biology ,Toxicology ,Microtubules ,Structure-Activity Relationship ,Cell Movement ,Tubulin ,Cell Line, Tumor ,medicine ,Humans ,Pharmacology (medical) ,Pyrroles ,Cell Proliferation ,Pharmacology ,Caspase 7 ,Cell growth ,Caspase 3 ,Cell Cycle ,Endothelial Cells ,Cell Differentiation ,Cell cycle ,Benzazepines ,Endothelial stem cell ,Enzyme Activation ,Oxazepines ,Oncology ,Cell culture ,Cancer research ,Carbamates ,Drug Screening Assays, Antitumor ,K562 cells - Abstract
Some members of a novel series of pyrrolo-1,5-benzoxazepines (PBOXs) are microtubule-targeting agents capable of inducing apoptosis in a variety of human cancerous cells, hence, they are currently being developed as potential anti-cancer agents. The purpose of this study was to first characterise the activities of a novel PBOX analogue, PBOX-16 and then investigate the anti-angiogenic potential of both PBOX-16 and its prototype PBOX-6. The effects of PBOX-6 and -16 on cancerous cells (chronic myeloid leukaemia K562 cells and ovarian carcinoma A2780 cells) and primary cultured human umbilical vein endothelial cells (HUVECs) were examined by assessing cell proliferation, microtubular organisation, DNA analysis of cell cycle progression and caspase-3/7 activity. Their anti-angiogenic properties were then investigated by examining their ability to interfere with HUVEC differentiation into capillary-like structures and vascular endothelial growth factor (VEGF)-stimulated HUVEC migration. PBOX-6 and -16 inhibited proliferation of K562, A2780 and HUVEC cells in a concentration-dependent manner. PBOX-16, confirmed as a novel depolymerising agent, was approximately tenfold more potent than PBOX-6. Inhibition of cell proliferation was mediated by G2/M arrest followed by varying degrees of apoptosis depending on the cell type; endothelial cells underwent less apoptosis than either of the cancer cell lines. In addition to the anti-tumourigenic properties, we also describe a novel anti-angiogenic function for PBOXs: treatment with PBOXs inhibited the spontaneous differentiation of HUVECs into capillary-like structures when grown on a basement membrane matrix preparation (Matrigel™) and also significantly reduced VEGF-stimulated HUVEC migration. Dual targeting of both the tumour cells and the host endothelial cells by PBOX compounds might enhance the anti-cancer efficacy of these drugs.
- Published
- 2009
91. Beta-lactam type molecular scaffolds for antiproliferative activity: synthesis and cytotoxic effects in breast cancer cells
- Author
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Mary J. Meegan, Miriam Carr, Daniela M. Zisterer, David Lloyd, Andrew J. S. Knox, Meegan, Mary J, Carr, Miriam, Knox, Andrew JS, Zisterer, Daniela M, and Lloyd, David G
- Subjects
antiproliferative activity ,β-Lactam ,Stereochemistry ,Molecular Conformation ,Antineoplastic Agents ,Breast Neoplasms ,beta-Lactams ,chemistry.chemical_compound ,Structure-Activity Relationship ,Cell Line, Tumor ,Drug Discovery ,medicine ,Potency ,Cytotoxic T cell ,Humans ,skin and connective tissue diseases ,Cytotoxicity ,Pharmacology ,Chemistry ,Aryl ,azetidin-2-one ,General Medicine ,Receptors, Estrogen ,Drug Design ,Lactam ,Amine gas treating ,Female ,Breast cancer cells ,SERMs ,Tamoxifen ,medicine.drug - Abstract
A series of novel beta-lactam containing compounds are described as antiproliferative agents and potential selective modulators of the oestrogen receptor. The purpose of the study is to evaluate the antiproliferative effects of these compounds on human MCF-7 and MDA MB-231 breast cancer cells. The compounds are designed to contain three aryl ring substituents arranged on the heterocyclic azetidin-2-one (beta-lactam), thus providing conformationally restrained analogues of the triarylethylene arrangement exemplified in the tamoxifen type structure. The compounds demonstrated potency in antiproliferative assays against MCF-7 human breast cancer cell line at low micromolar to nanomolar concentrations with low cytotoxicity and moderate binding affinity to the oestrogen receptor. The effect of a number of aryl and amine functional group substitutions on the antiproliferative activity of the beta-lactam products was explored and a brief computational structure-activity relationship investigation with molecular simulation was investigated.
- Published
- 2008
92. Benzothiepin-derived molecular scaffolds for estrogen receptor modulators: synthesis and antagonistic effects in breast cancer cells
- Author
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Jochen Zimmermann, Mary J. Meegan, Daniela M. Zisterer, David Lloyd, Andrew J. S. Knox, Irene Barrett, Meegan, Mary J., Barrett, Irene, Zimmermann, Jochen, Knox, Andrew J. S., and Zisterer, Daniela M.
- Subjects
antiproliferative activity ,Models, Molecular ,Benzothiepin ,Estrogen receptor ,Antineoplastic Agents ,Breast Neoplasms ,Biology ,Pharmacology ,Benzothiepins ,Binding, Competitive ,Estrogen Receptor Antagonists ,Inhibitory Concentration 50 ,Estrogen Receptor Modulators ,estrogen receptor antagonists ,Cell Line, Tumor ,Drug Discovery ,medicine ,Humans ,skin and connective tissue diseases ,Receptor ,Cytotoxicity ,Estrogen receptor beta ,Cell Proliferation ,Binding Sites ,Molecular Structure ,Cell growth ,General Medicine ,Receptors, Estrogen ,Cell culture ,Cancer research ,Female ,Drug Screening Assays, Antitumor ,SERMs ,hormones, hormone substitutes, and hormone antagonists ,Tamoxifen ,medicine.drug - Abstract
A series of novel benzothiepin-derived compounds are described as potent selective modulators of the human estrogen receptor (SERMs). The objective of the study is to evaluate the antiproliferative effects of the compounds on human MCF-7 breast tumor cells. These heterocyclic compounds contain the traditional triarylethylene arrangement exemplified by tamoxifen, conformationally restrained through the incorporation of the benzothiepin ring system. The compounds demonstrated potency at nanomolar concentrations in antiproliferative assays against an MCF-7 human breast cancer cell line with low cytotoxicity. The compounds exhibited low nanomolar binding affinity for the estrogen receptor (ER) with some specificity for ERbeta, and also demonstrate potent antiestrogenic properties in the human uterine Ishikawa cell line. The effect of a number of functional group substitutions on the ER binding properties of the benzothiepin molecular scaffold is explored through a brief computational structure-activity relationship investigation with molecular simulation.
- Published
- 2007
93. BubR1 is required for a sustained mitotic spindle checkpoint arrest in human cancer cells treated with tubulin-targeting pyrrolo-1,5-benzoxazepines
- Author
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Mark Lawler, Giuseppe Campiani, D. Clive Williams, Daniela M. Zisterer, and Lisa M. Greene
- Subjects
Cell cycle checkpoint ,BUB3 ,Mitosis ,Apoptosis ,HL-60 Cells ,Spindle Apparatus ,Biology ,Protein Serine-Threonine Kinases ,chemistry.chemical_compound ,Tubulin ,Cell Line, Tumor ,Neoplasms ,Humans ,Pyrroles ,Pharmacology ,G2-M DNA damage checkpoint ,Mitotic spindle checkpoint ,Cell biology ,Spindle checkpoint ,Nocodazole ,Oxazepines ,chemistry ,Molecular Medicine ,Anaphase-promoting complex ,K562 Cells - Abstract
Intrinsic or acquired resistance to chemotherapy is a major clinical problem that has evoked the need to develop innovative approaches to predict and ultimately reverse drug resistance. A prolonged G 2 M arrest has been associated with apoptotic resistance to various microtubule-targeting agents (MTAs). In this study, we describe the functional significance of the mitotic spindle checkpoint proteins, BubR1 and Bub3, in maintaining a mitotic arrest after microtubule disruption by nocodazole and a novel series of MTAs, the pyrrolo-1,5-benzoxazepines (PBOXs), in human cancer cells. Cells expressing high levels of BubR1 and Bub3 (K562, MDA-MB-231, and HeLa) display a prolonged G 2 M arrest after exposure to MTAs. On the other hand, cells with low endogenous levels of mitotic spindle checkpoint proteins (SK-BR-3 and HL-60) transiently arrest in mitosis and undergo increased apoptosis. The phosphorylation of BubR1 correlated with PBOX-induced G 2 M arrest in four cell lines tested, indicating an active mitotic spindle checkpoint. Gene silencing of BubR1 by small interfering RNA interference reduced PBOX-induced G 2 M arrest without enhancing apoptotic efficacy. Further analysis demonstrated that PBOX-treated BubR1-depleted cells were both mononucleated and multinucleated with a polyploid DNA content, suggesting a requirement for BubR1 in cytokinesis. Taken together, these results suggest that BubR1 contributes to the mitotic checkpoint induced by the PBOXs.
- Published
- 2007
94. A new microtubule-targeting compound PBOX-15 inhibits T-cell migration via post-translational modifications of tubulin
- Author
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Giuseppe Campiani, Anthony Davies, D. Clive Williams, Peter Olwell, Jennifer Conroy, Daniela M. Zisterer, Navin Kumar Verma, Eugene M. Dempsey, Stefania Butini, Mark Lawler, Dermot Kelleher, Yuri Volkov, and Anthony M. McElligott
- Subjects
T-Lymphocytes ,Integrin ,Apoptosis ,Microtubules ,PBOX ,Microtubule ,Cell Movement ,Tubulin ,PBOX, T-cell migration, Tubulin ,Cell Line, Tumor ,Drug Discovery ,Humans ,Pyrroles ,Lymphocyte function-associated antigen 1 ,Cytoskeleton ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,Genetics (clinical) ,biology ,Tubulin Modulators ,Cell migration ,Lymphocyte Function-Associated Antigen-1 ,Cell biology ,Oxazepines ,Phenotype ,T-cell migration - PBOX - Tubulin ,biology.protein ,Molecular Medicine ,Protein Processing, Post-Translational ,T-cell migration - Abstract
PUBLISHED, The ordered, directional migration of T-lymphocytes is a key process during immune surveillance, immune response, and development. A novel series of pyrrolo-1,5-benzoxazepines have been shown to potently induce apoptosis in variety of human chemotherapy resistant cancer cell lines, indicating their potential in the treatment of both solid tumors and tumors derived from the hemopoietic system. Pyrrolobenzoxazepine 4-acetoxy-5-(1-naphtyl)naphtho[2,3-b]pyrrolo[1,2-d][1,4]-oxazepine (PBOX-15) has been shown to depolymerize tubulin in vitro and in the MCF7 breast cancer cell line. We hypothesized that this may suggest a role for this compound in modulating integrin-induced T-cell migration, which is largely dependent on the microtubule dynamics. Experiments were performed using human T lymphoma cell line Hut78 and peripheral blood T-lymphocytes isolated from healthy donors. We observed that human T-lymphocytes exposed to PBOX-15 have severely impaired ability to polarize and migrate in response to the triggering stimulus generated via cross-linking of integrin lymphocyte function associated antigen-1 receptor. Here, we show that PBOX-15 can dramatically impair microtubule network via destabilization of tubulin resulting in complete loss of the motile phenotype of T-cells. We demonstrate that PBOX-15 inhibitory mechanisms involve decreased tubulin polymerization and its post-translational modifications. Novel microtubule-targeting effects of PBOX-15 can possibly open new horizons in the treatment of overactive inflammatory conditions as well as cancer and cancer metastatic spreading., This work was supported by a Grant from the Higher Education Authority of Ireland under the department of Education and Science?s Program for Research in Third Level Institutions and the Health Research Board of Ireland.
- Published
- 2007
95. Target specific virtual screening: optimization of an estrogen receptor screening platform
- Author
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David Lloyd, Mary J. Meegan, Daniela M. Zisterer, D. Frost, Vladimir Sobolev, D. Clive Williams, Andrew J. S. Knox, Knox, Andrew J S, Meegan, Mary J, Sobolev, Vladimir, Frost, Dermot, Zisterer, Daniela M, and Williams, D Clive
- Subjects
Models, Molecular ,Molecular model ,Databases, Factual ,Stereochemistry ,Receptor Binding ,Molecular Conformation ,Estrogen receptor ,Quantitative Structure-Activity Relationship ,Antineoplastic Agents ,Computational biology ,Normalized Complementarity ,Ligands ,Binding, Competitive ,Estrogen Receptor Modulators ,Cell Line, Tumor ,Drug Discovery ,Biochemical Testing ,Estrogen Receptor beta ,Humans ,Cytotoxicity ,Binding affinities ,Virtual screening ,Binding Sites ,Ligand ,Chemistry ,Estrogen Receptor alpha ,Tamoxifen ,Docking (molecular) ,Molecular Medicine ,Drug Screening Assays, Antitumor ,Artifacts ,Estrogen receptor alpha - Abstract
In this work, we introduce a four-step scoring and filtering procedure, furnishing target specific virtual screening (TS-VS), which serves to minimize false positives resulting from conformational artifacts of the docking process and is optimized to converge on novel chemotypes of estrogen receptor alpha (ERalpha). As a proof of concept, VS of a commercial compound database was undertaken (SPECs database release: Aug 2005, 202 054 compounds in total), resulting in the identification of both previously known and novel putative ER scaffolds. Application of distance constraints within TS-VS allowed facile identification of three novel active ligands with ERalpha binding affinities (IC50) of 1.4 microM, 57 nM, and 53 nM. Importantly, they all exhibited ERalpha over ERbeta selectivity, with the most selective being 17-fold. The ligands also displayed low micomolar antiproliferative activity (7-15 microM) in the human MCF-7 breast cancer cell line.
- Published
- 2007
96. STI-571 (imatinib mesylate) enhances the apoptotic efficacy of pyrrolo-1,5-benzoxazepine-6, a novel microtubule-targeting agent, in both STI-571-sensitive and -resistant Bcr-Abl-positive human chronic myeloid leukemia cells
- Author
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Valeria Onnis, Lisa M. Greene, Mark Lawler, Giuseppe Campiani, D. Clive Williams, Daniela M. Zisterer, and Liam Kelly
- Subjects
Cell Survival ,Blotting, Western ,Fusion Proteins, bcr-abl ,bcl-X Protein ,Down-Regulation ,Apoptosis ,HL-60 Cells ,Poly(ADP-ribose) Polymerase Inhibitors ,Biology ,Microtubules ,Monocytes ,Piperazines ,chemistry.chemical_compound ,Cell Line, Tumor ,hemic and lymphatic diseases ,medicine ,Humans ,Pyrroles ,neoplasms ,Pharmacology ,Cell Cycle ,Myeloid leukemia ,Drug Synergism ,Cell cycle ,medicine.disease ,Neoplasm Proteins ,Myeloid Cell Leukemia Sequence 1 Protein ,Oxazepines ,Nocodazole ,Leukemia ,Pyrimidines ,Imatinib mesylate ,Proto-Oncogene Proteins c-bcl-2 ,chemistry ,Drug Resistance, Neoplasm ,Leukemia, Myeloid ,Benzamides ,Immunology ,Imatinib Mesylate ,Cancer research ,Molecular Medicine ,Poly(ADP-ribose) Polymerases ,K562 Cells ,K562 cells - Abstract
Interactions between the Bcr-Abl kinase inhibitor STI-571 (imatinib mesylate) and a novel microtubule-targeting agent (MTA), pyrrolo-1,5-benzoxazepine (PBOX)-6, were investigated in STI-571-sensitive and -resistant human chronic myeloid leukemia (CML) cells. Cotreatment of PBOX-6 with STI-571 induced significantly more apoptosis in Bcr-Abl-positive CML cell lines (K562 and LAMA-84) than either drug alone (P < 0.01). Cell cycle analysis of propidium iodide-stained cells showed that STI-571 significantly reduced PBOX-6-induced G2M arrest and polyploid formation with a concomitant increase in apoptosis. Similar results were obtained in K562 CML cells using lead MTAs (paclitaxel and nocodazole) in combination with STI-571. Potentiation of PBOX-6-induced apoptosis by STI-571 was specific to Bcr-Abl-positive leukemia cells with no cytoxic effects observed on normal peripheral blood cells. The combined treatment of STI-571 and PBOX-6 was associated with the down-regulation of Bcr-Abl and repression of proteins involved in Bcr-Abl transformation, namely the antiapoptotic proteins Bcl-x(L) and Mcl-1. Importantly, PBOX-6/STI-571 combinations were also effective in STI-571-resistant cells. Together, these findings highlight the potential clinical benefits in simultaneously targeting the microtubules and the Bcr-Abl oncoprotein in STI-571-sensitive and -resistant CML cells.
- Published
- 2007
97. Abstract B81: Combretastatin (CA)-4 and its novel analogue CA-432 impair T-cell migration through the Rho/ROCK signalling pathway
- Author
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Navin Kumar Verma, Mary J. Meegan, Daniela M. Zisterer, and Jade K. Pollock
- Subjects
Combretastatin ,Cancer Research ,Tumor microenvironment ,RHOA ,Immunology ,Cell migration ,Biology ,Hedgehog signaling pathway ,Cell biology ,chemistry.chemical_compound ,chemistry ,biology.protein ,Viability assay ,Lamellipodium ,Signal transduction - Abstract
Background: The capacity of T-cell lymphocytes to migrate and localize in tissues is important in their protective function against infectious agents, however, the ability of these cells to migrate and infiltrate the tumor microenvironment is also a major contributing factor in the development of cancer and cancer metastasis. T-cell migration requires ligand (ICAM-1)/integrin(LFA-1) interaction, activating intracellular signaling pathways which result in a distinct polarized morphology, with an actin-rich lamellipodium and microtubule-rich uropod. Microtubule-targeting agents (MTAs) are amongst some of the most widely used anti-cancer drugs and several have been shown to exhibit anti-inflammatory activity. Combretastatin (CA) A-4 is a MT-destabilizing agent that possesses potent anti-tumor and anti-vascular properties both in vitro and in vivo. CA-432, a novel cis-restriciting analogue containing a β-lactam ring, has recently been synthesized to circumvent the problem of CA-4 isomerisation from a biologically active cis-conformation to a more thermodynamically stable but inactive trans-isomer. Methods: HuT-78 cell line and peripheral blood lymphocyte (PBL) T-cells were cultured. In this study, the effect of CA-4 and CA-432 on the migratory polarity of T-cells was explored using high content analysis (HCA). The active migration of PBL T-cells was studied using a transwell assay. The mechanistic and signaling pathways involved were examined using western blotting and confocal microscopy. Cytoxicity of both compounds was tested using a viability assay and flow cytometry. Results: CA-4 and CA-432 treated cells displayed altered T-cell migratory polarity in HuT-78 and peripheral blood T-lymphocyte (PBTL) cells and inhibited active migration of PBTLs. Both compounds induced activation of the RhoA / RhoA associated kinase (ROCK) signaling pathway, leading to the phosphorylation of myosin light chain (MLC), acto-myosin contractility and impaired migration. Disruption of the MT network of T-cells through CA-induced MT depolymerisation was associated with reduced acetylated tubulin expression and decreased MT stability. GEF-H1 is a MT-associated nucleotide exchange factor which activates RhoA upon release from MTs, The siRNA-mediated depletion of GEF-H1 in Hut-78 T cells prevented CA-induced phosphorylation of MLC and attenuated the formation of actin-rich membrane protrusions and cell contractility. Conclusions: These results suggest an important role for a GEF-H1/RhoA/ROCK/MLC signaling pathway in mediating CA-induced contractility of T cells. Therapeutic agents inhibiting cell migration may open new avenues in the treatment of cancer and metastasis. Citation Format: Jade Kirstin Pollock, Navin K. Verma, Mary J. Meegan, Daniela Zisterer. Combretastatin (CA)-4 and its novel analogue CA-432 impair T-cell migration through the Rho/ROCK signalling pathway. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy: A New Chapter; December 1-4, 2014; Orlando, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2015;3(10 Suppl):Abstract nr B81.
- Published
- 2015
98. Caspase-activated DNase (CAD)-independent oligonucleosomal DNA fragmentation in chronic myeloid leukaemia cells; a requirement for serine protease and Mn2+-dependent acidic endonuclease activity
- Author
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L. B. McGrath, Giuseppe Campiani, Valeria Onnis, D. C. Williams, Margaret M. Mc Gee, and Daniela M. Zisterer
- Subjects
Cell Extracts ,Cancer Research ,Proteases ,Cytoplasm ,Clinical Biochemistry ,Pharmaceutical Science ,Apoptosis ,DNA Fragmentation ,Caspase-activated DNase ,Leukemia, Myelogenous, Chronic, BCR-ABL Positive ,Humans ,Pyrroles ,Fragmentation (cell biology) ,Phosphorylation ,Caspase ,Pharmacology ,Serine protease ,Manganese ,Deoxyribonucleases ,biology ,Caspase 3 ,Biochemistry (medical) ,Serine Endopeptidases ,Cell Biology ,Hydrogen-Ion Concentration ,Endonucleases ,Molecular biology ,Mitochondria ,Oxazepines ,HtrA serine peptidase 2 ,Proto-Oncogene Proteins c-bcl-2 ,biology.protein ,DNA fragmentation ,K562 Cells ,Peptide Hydrolases - Abstract
We have previously reported that the pro-apoptotic pyrrolobenzoxazepine, PBOX-6, induces apoptosis in chronic myelogenous leukaemia (CML) cells which is accompanied by oligonucleosomal DNA fragmentation. In this study we show that PBOX-6-induced oligonucleosomal DNA fragmentation occurs in the absence of caspase and CAD activation in CML cells. Dissection of the signalling pathway has revealed that induction of apoptosis requires the upstream activation of a trypsin-like serine protease that promotes the phosphorylation and inactivation of anti-apoptotic Bcl-2. In addition, in this system chymotrypsin-like serine proteases are dispensable for high molecular weight DNA fragmentation, however are required for the activation of a relatively small manganese-dependent acidic endonuclease that is responsible for oligonucleosomal fragmentation of DNA. Furthermore, we demonstrate mitochondrial involvement during PBOX-6-induced apoptosis and suggest the existence of unidentified mitochondrial effectors of apoptosis.
- Published
- 2006
99. Synthesis, structure-activity relationships and antagonistic effects in human MCF-7 breast cancer cells of flexible estrogen receptor modulators
- Author
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David G, Lloyd, Helena M, Smith, Timothy, O'Sullivan, Daniela M, Zisterer, and Mary J, Meegan
- Subjects
Stereochemistry ,Estrogen receptor ,Antineoplastic Agents ,Breast Neoplasms ,Binding, Competitive ,Estrogen Receptor Antagonists ,Structure-Activity Relationship ,Estrogen Receptor Modulators ,Cell Line, Tumor ,Drug Discovery ,medicine ,Structure–activity relationship ,Humans ,Raloxifene ,Computer Simulation ,Estrogen receptor beta ,Cell Proliferation ,Molecular Structure ,Chemistry ,MCF-7 ,Selective estrogen receptor modulator ,Drug Design ,Female ,Drug Screening Assays, Antitumor ,hormones, hormone substitutes, and hormone antagonists ,Tamoxifen ,medicine.drug - Abstract
Estrogen receptors are therapeutic intervention targets for diseases such as osteoporosis and breast cancer with both tamoxifen and raloxifene established as clinical estrogen receptor antagonists. We report a series of novel selective estrogen receptor modulators (SERMs) whose structures are based on a flexible core scaffold differing from the triphenylethylene of tamoxifen analogues through the insertion of a benzylic methylene group as a flexible spacer between the aryl ring C and the ethylene group. A facile synthesis of the target compounds utilises the titanium tetrachloride/zinc mediated McMurry coupling reaction. Successive introduction onto the parent scaffold of hydroxyl functional groups afforded a series of increased potency ligands for the ER - essentially exploring the predicted in vivo metabolic activation of such aromatic SERM ligands. This second generation compound series demonstrated high antiproliferative potency against the MCF-7 human breast cancer cell line, with low cytotoxicity. High ER binding affinity (IC50 20 nM) together with up to 12 fold ERalpha/beta selectivity was also observed. In addition, the compounds displayed antiestrogenic effects at 40 nM when evaluated in the Ishikawa cell line with little estrogenic stimulation. Representative ligands were shown to be pro-apoptotic in human MCF-7 cells in a FACS based assay. Comparison of the docked structure obtained for the most active compound with the X-ray crystal structure reported for the complex of ERalpha and 4-hydroxytamoxifen, predict that these ligands bind in an antiestrogenic manner with some differences being observed in the benzylic Ring C orientation, as expected. This work further demonstrates the tolerance of the estrogen receptor towards flexible modulators.
- Published
- 2006
100. The pyrrolo-1,5-benzoxazepine, PBOX-6, inhibits the growth of breast cancer cells in vitro independent of estrogen receptor status and inhibits breast tumour growth in vivo
- Author
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Gregory J. Atkins, D. Clive Williams, Marina N. Fleeton, Vito Nacci, Lisa M. Greene, Mark Lawler, Giuseppe Campiani, Jude M. Mulligan, Chikkanna C. Gowda, Brian J. Sheahan, and Daniela M. Zisterer
- Subjects
Cancer Research ,medicine.medical_specialty ,Programmed cell death ,Oncogene ,Cell growth ,Estrogen receptor ,General Medicine ,Cell cycle ,Biology ,Endocrinology ,Oncology ,Apoptosis ,Internal medicine ,medicine ,Cancer research ,Viability assay ,Estrogen Receptor Status - Abstract
Members of a novel series of pyrrolo-1,5-benzoxazepine (PBOX) compounds have been shown to induce apoptosis in a number of human leukemia cell lines of different haematological lineage, suggesting their potential as anti-cancer agents. In this study, we sought to determine if PBOX-6, a well characterised member of the PBOX series of compounds, is also an effective inhibitor of breast cancer growth. Two estrogen receptor (ER)-positive (MCF-7 and T-47-D) and two ER-negative (MDA-MB-231 and SK-BR-3) cell lines were examined. The 3,4,5-dimethylthiazol-2-yl-2,5-diphenyl-tetrazolium bromide (MTT) assay was used to determine reduction in cell viability. PBOX-6 reduced the cell viability of all four cell lines tested, regardless of ER status, with IC(50) values ranging from 1.0 to 2.3 microM. PBOX-6 was most effective in the SK-BR-3 cells, which express high endogenous levels of the HER-2 oncogene. Overexpression of the HER-2 oncogene has been associated with aggressive disease and resistance to chemotherapy. The mechanism of PBOX-6-induced cell death was due to apoptosis, as indicated by the increased proportion of cells in the pre-G1 peak and poly(ADP-ribose) polymerase (PARP) cleavage. Moreover, intratumoural administration of PBOX-6 (7.5 mg/kg) significantly inhibited tumour growth in vivo in a mouse mammary carcinoma model (p=0.04, n=5, Student's t-test). Thus, PBOX-6 could be a promising anti-cancer agent for both hormone-dependent and -independent breast cancers.
- Published
- 2005
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