21 results on '"Hepperle M"'
Search Results
2. Use of molecular imaging to quantify response to IKK-2 inhibitor treatment in murine arthritis.
- Author
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Izmailova ES, Paz N, Alencar H, Chun M, Schopf L, Hepperle M, Lane JH, Harriman G, Xu Y, Ocain T, Weissleder R, Mahmood U, Healy AM, and Jaffee B
- Abstract
OBJECTIVE: The NF-kappaB signaling pathway promotes the immune response in rheumatoid arthritis (RA) and in rodent models of RA. NF-kappaB activity is regulated by the IKK-2 kinase during inflammatory responses. To elucidate how IKK-2 inhibition suppresses disease development, we used a combination of in vivo imaging, transcription profiling, and histopathology technologies to study mice with antibody-induced arthritis. METHODS: ML120B, a potent, small molecule inhibitor of IKK-2, was administered to arthritic animals, and disease activity was monitored. NF-kappaB activity in diseased joints was quantified by in vivo imaging. Quantitative reverse transcriptase-polymerase chain reaction was used to evaluate gene expression in joints. Protease-activated near-infrared fluorescence (NIRF) in vivo imaging was applied to assess the amounts of active proteases in the joints. RESULTS: Oral administration of ML120B suppressed both clinical and histopathologic manifestations of disease. In vivo imaging demonstrated that NF-kappaB activity in inflamed arthritic paws was inhibited by ML120B, resulting in significant suppression of multiple genes in the NF-kappaB pathway, i.e., KC, epithelial neutrophil-activating peptide 78, JE, intercellular adhesion molecule 1, CD3, CD68, tumor necrosis factor alpha, interleukin-1beta, interleukin-6, inducible nitric oxide synthase, cyclooxygenase 2, matrix metalloproteinase 3, cathepsin B, and cathepsin K. NIRF in vivo imaging demonstrated that ML120B treatment dramatically reduced the amount of active proteases in the joints. CONCLUSION: Our data demonstrate that IKK-2 inhibition in the murine model of antibody-induced arthritis suppresses both inflammation and joint destruction. In addition, this study highlights how gene expression profiling can facilitate the identification of surrogate biomarkers of disease activity and treatment response in an experimental model of arthritis. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
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3. IKKbeta inhibition protects against bone and cartilage destruction in a rat model of rheumatoid arthritis.
- Author
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Schopf L, Savinainen A, Anderson K, Kujawa J, DuPont M, Silva M, Siebert E, Chandra S, Morgan J, Gangurde P, Wen D, Lane J, Xu Y, Hepperle M, Harriman G, Ocain T, and Jaffee B
- Abstract
OBJECTIVE: The IKK complex regulates NF-kappaB activation, an important pathway implicated in the rheumatoid arthritis (RA) disease process. This study was undertaken to assess the efficacy of N-(6-chloro-7-methoxy-9H-beta-carbolin-8-yl)-2-methylnicotinami de (ML120B), a potent and selective small molecule inhibitor of IKKbeta. METHODS: Polyarthritis was induced in rats by injection of Freund's complete adjuvant into the hind footpad. ML120B was administered orally twice daily, either prophylactically or therapeutically. Paw volumes and body weights were measured every 2-3 days throughout the study. We assessed bone erosions by several methods: histologic evaluation, quantitative micro-computed tomography (micro-CT) imaging analysis, and measurement of type I collagen fragments in the serum. Quantitative polymerase chain reaction was used to evaluate expression of messenger RNA for genes related to inflammation and to bone and cartilage integrity. RESULTS: Oral administration of ML120B inhibited paw swelling in a dose-dependent manner (median effective dosage 12 mg/kg twice daily) and offered significant protection against arthritis-induced weight loss as well as cartilage and bone erosion. We were able to directly demonstrate that NF-kappaB activity in arthritic joints was reduced after ML120B administration. Also, we observed that down-regulation of the NF-kappaB pathway via IKKbeta inhibition dampened the chronic inflammatory process associated with rat adjuvant-induced arthritis. CONCLUSION: The results of the present study suggest that IKKbeta inhibition is an effective therapeutic approach to treat both the inflammation and the bone/cartilage destruction observed in RA. Methods for the determination of serum markers for bone and cartilage destruction, as well as micro-CT analysis, may aid in predicting and evaluating the therapeutic efficacy of IKKbeta inhibition therapy in humans. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
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4. A research method to induce and examine a mild exacerbation of asthma by withdrawal of inhaled corticosteroid.
- Author
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Gibson, P. G., Wong, B. J. O., Hepperle, M. J. E., Kline, P. A., Girgis-Gabardo, A., Guyatt, G., Dolovich, J., Denburg, J. A., Ramsdale, E. H., and Hargreave, F. E.
- Subjects
ASTHMA ,CORTICOSTEROIDS ,BRONCHIAL diseases ,STEROID hormones ,PULMONARY function tests ,ADRENAL cortex ,OBSTRUCTIVE lung diseases - Abstract
This study evaluated a research method to examine an exacerbation of asthma induced by corticosteroid withdrawal. Ten non-smoking adult asthmatics who were stable on treatment with inhaled steroid underwent a graded reduction of the daily dose by 200 pg at weekly intervals until an exacerbation of symptoms occurred. A daily symptom, peak expiratory flow rate (PEF) and medication diary was kept. Weekly clinic visits were used to assess symptoms, spirometry, methacholine airway responsiveness (expressed as the provocative concentration to cause a fall in FEV
1 of 20%,PC20 ), circulating eosinophils, basophils and their progenitors (Eo/B-CFU), and sputum inflammatory cells. The laboratory tests were performed blind to the clinical details. Each subject developed an exacerbation of symptoms, on average at 16 (7-26) days after the onset of steroid reduction. This was accompanied by a deterioration in each of the objective measures. There was a fall in FEV, by 320 ml (s.e.m. 95) and in PC20 from 0.8 to 0.43 mg/ml. Circulating eosinophils rose from 114 (24) × 10³/ml to 227 (50) × 10³/ml and Eo/B-CFU rose from 31 (5.6) to 44 (11.3)/106 cells. Sputum developed in five subjects and contained 36 (5.2)% eosinophils and 1.98 (0.21)% metachromatic cells (mast cells or basophils). The symptom diary and weekly questionaire were demonstrated to be valid and responsive to change. A deterioration indicated by the daily symptom score preceded changes in PEF. Treatment by an increase in steroid was followed by reversal of each of the changes. We conclude that this research method can safely produce and examine a mild exacerbation of asthma, and that an increase in airway inflammation is an early feature. [ABSTRACT FROM AUTHOR]- Published
- 1992
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5. ChemInform Abstract: Synthesis of 2-O-Heteroaroyl Taxanes: Evaluation of Microtubule Assembly Promotion and Cytotoxicity.
- Author
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GEORG, G. I., HARRIMAN, G. C. B., ALI, S. M., DATTA, A., HEPPERLE, M., and HIMES, R. H.
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- 1995
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6. ChemInform Abstract: Synthesis and Biology of Substituted 3′-Phenyl Taxol Analogues.
- Author
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GEORG, G. I., CHERUVALLATH, Z. S., HARRIMAN, G. C. B., HEPPERLE, M., PARK, H., and HIMES, R. H.
- Published
- 1995
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7. ChemInform Abstract: Topliss Approach to the Synthesis of Biologically Active Substituted N- Benzoyl Taxol Analogues.
- Author
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GEORG, G. I., BOGE, T. C., CHERUVALLATH, Z. S., HARRIMAN, G. C. B., HEPPERLE, M., PARK, H., and HIMES, R. H.
- Published
- 1995
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8. ChemInform Abstract: Heteroaromatic Taxol Analogues: The Chemistry and Biological Activities of 3′-Furyl and 3′-Pyridyl Substituted Taxanes.
- Author
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GEORG, G. I., HARRIMAN, G. C. B., HEPPERLE, M., and HIMES, R. H.
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- 1994
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9. ChemInform Abstract: Schotten-Baumann Acylation of N-Debenzoyltaxol; An Efficient Route to N-Acyl Taxol Analogues and Their Biological Evaluation.
- Author
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GEORG, G. I., BOGE, T. C., CHERUVALLATH, Z. S., HARRIMAN, G. C. B., HEPPERLE, M., PARK, H., and HIMES, R. H.
- Published
- 1994
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10. Design, synthesis and activity of a potent, selective series of N-aryl pyridinone inhibitors of p38 kinase.
- Author
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Selness SR, Boehm TL, Walker JK, Devadas B, Durley RC, Kurumbail R, Shieh H, Xing L, Hepperle M, Rucker PV, Jerome KD, Benson AG, Marrufo LD, Madsen HM, Hitchcock J, Owen TJ, Christie L, Promo MA, Hickory BS, Alvira E, Naing W, Blevis-Bal R, Devraj RV, Messing D, Schindler JF, Hirsch J, Saabye M, Bonar S, Webb E, Anderson G, and Monahan JB
- Subjects
- Animals, Disease Models, Animal, Enzyme Activation drug effects, Enzyme Inhibitors chemistry, Humans, Inhibitory Concentration 50, Male, Microsomes, Liver enzymology, Molecular Structure, Pyridazines chemistry, Pyridazines pharmacology, Pyridones chemistry, Pyrimidines chemistry, Pyrimidines pharmacology, Rats, Rats, Sprague-Dawley, Drug Design, Enzyme Inhibitors chemical synthesis, Enzyme Inhibitors pharmacology, Pyridones chemical synthesis, Pyridones pharmacology, p38 Mitogen-Activated Protein Kinases antagonists & inhibitors
- Abstract
A series of N-aryl pyridinone inhibitors of p38 mitogen activated protein (MAP) kinase were designed and prepared based on the screening hit SC-25028 (1) and structural comparisons to VX-745 (5). The focus of the investigation targeted the dependence of potency and metabolic stability on the benzyloxy connectivity, the role of the C-6 position and the substitution pattern on the N-phenyl ring. Further optimization produced the highly selective and potent pyridinones 2 and 3. These inhibitors exhibited activity in both acute and chronic models of inflammation., (Copyright © 2011 Elsevier Ltd. All rights reserved.)
- Published
- 2011
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11. Discovery of N-substituted pyridinones as potent and selective inhibitors of p38 kinase.
- Author
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Selness SR, Devraj RV, Monahan JB, Boehm TL, Walker JK, Devadas B, Durley RC, Kurumbail R, Shieh H, Xing L, Hepperle M, Rucker PV, Jerome KD, Benson AG, Marrufo LD, Madsen HM, Hitchcock J, Owen TJ, Christie L, Promo MA, Hickory BS, Alvira E, Naing W, and Blevis-Bal R
- Subjects
- Administration, Oral, Animals, Anti-Inflammatory Agents chemical synthesis, Anti-Inflammatory Agents pharmacokinetics, Binding Sites, Catalytic Domain, Crystallography, X-Ray, Drug Discovery, Humans, JNK Mitogen-Activated Protein Kinases antagonists & inhibitors, JNK Mitogen-Activated Protein Kinases metabolism, Male, Microsomes, Liver metabolism, Protein Kinase Inhibitors chemical synthesis, Protein Kinase Inhibitors pharmacokinetics, Pyridones chemical synthesis, Pyridones pharmacokinetics, Rats, Rats, Sprague-Dawley, Structure-Activity Relationship, p38 Mitogen-Activated Protein Kinases metabolism, Anti-Inflammatory Agents chemistry, Protein Kinase Inhibitors chemistry, Pyridones chemistry, p38 Mitogen-Activated Protein Kinases antagonists & inhibitors
- Abstract
The identification and evolution of a series of potent and selective p38 inhibitors is described. p38 inhibitors based on a N-benzyl pyridinone high-throughput screening hit were prepared and their SAR explored. Their design was guided by ligand bound co-crystals of p38alpha. These efforts resulted in the identification of 12r and 19 as orally active inhibitors of p38 with significant efficacy in both acute and chronic models of inflammation.
- Published
- 2009
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12. SD0006: a potent, selective and orally available inhibitor of p38 kinase.
- Author
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Burnette BL, Selness S, Devraj R, Jungbluth G, Kurumbail R, Stillwell L, Anderson G, Mnich S, Hirsch J, Compton R, De Ciechi P, Hope H, Hepperle M, Keith RH, Naing W, Shieh H, Portanova J, Zhang Y, Zhang J, Leimgruber RM, and Monahan J
- Subjects
- Administration, Oral, Animals, Bone Density drug effects, Cell Line, Endotoxemia drug therapy, Endotoxemia metabolism, Female, Humans, Inflammation drug therapy, Inflammation metabolism, Inflammation physiopathology, Inflammation Mediators antagonists & inhibitors, Inflammation Mediators metabolism, Lipopolysaccharides pharmacology, Macaca fascicularis, Male, Mice, Mice, Inbred DBA, Models, Molecular, Pain drug therapy, Rats, Rats, Inbred Lew, Rats, Sprague-Dawley, Tumor Necrosis Factor-alpha antagonists & inhibitors, Tumor Necrosis Factor-alpha metabolism, p38 Mitogen-Activated Protein Kinases metabolism, Anti-Inflammatory Agents, Non-Steroidal pharmacology, Anti-Inflammatory Agents, Non-Steroidal therapeutic use, Arthritis, Experimental drug therapy, Pyrazoles pharmacology, Pyrazoles therapeutic use, Pyrimidines pharmacology, Pyrimidines therapeutic use, p38 Mitogen-Activated Protein Kinases antagonists & inhibitors
- Abstract
SD0006 is a diarylpyrazole that was prepared as an inhibitor of p38 kinase-alpha (p38alpha). In vitro, SD0006 was selective for p38alpha kinase over 50 other kinases screened (including p38gamma and p38delta with modest selectivity over p38beta). Crystal structures with p38alpha show binding at the ATP site with additional residue interactions outside the ATP pocket unique to p38alpha that can confer advantages over other ATP competitive inhibitors. Direct correlation between inhibition of p38alpha activity and that of lipopolysaccharide-stimulated TNFalpha release was established in cellular models and in vivo, including a phase 1 clinical trial. Potency (IC(50)) for inhibiting tumor necrosis factor-alpha (TNFalpha) release, in vitro and in vivo, was <200 nmol/l. In vivo, SD0006 was effective in the rat streptococcal-cell-wall-induced arthritis model, with dramatic protective effects on paw joint integrity and bone density as shown by radiographic analysis. In the murine collagen-induced arthritis model, equivalence was demonstrated to anti-TNFalpha treatment. SD0006 also demonstrated good oral anti-inflammatory efficacy with excellent cross-species correlation between the rat, cynomolgus monkey, and human. SD0006 suppressed expression of multiple proinflammatory proteins at both the transcriptional and translational levels. These properties suggest SD0006 could provide broader therapeutic efficacy than cytokine-targeted monotherapeutics.
- Published
- 2009
- Full Text
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13. Rapid TNFR1-dependent lymphocyte depletion in vivo with a selective chemical inhibitor of IKKbeta.
- Author
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Nagashima K, Sasseville VG, Wen D, Bielecki A, Yang H, Simpson C, Grant E, Hepperle M, Harriman G, Jaffee B, Ocain T, Xu Y, and Fraser CC
- Subjects
- Animals, Apoptosis drug effects, B-Lymphocytes drug effects, Bone Marrow Cells drug effects, Enzyme Inhibitors pharmacology, Granulocytes drug effects, Granulocytes metabolism, Hematopoietic Stem Cells drug effects, Mice, Mice, Knockout, Receptors, Tumor Necrosis Factor, Receptors, Tumor Necrosis Factor, Type I deficiency, Receptors, Tumor Necrosis Factor, Type II deficiency, Receptors, Tumor Necrosis Factor, Type II physiology, Tumor Necrosis Factor Decoy Receptors, Tumor Necrosis Factor-alpha pharmacology, I-kappa B Kinase antagonists & inhibitors, Lymphocyte Depletion methods, Receptors, Tumor Necrosis Factor, Type I physiology
- Abstract
The transcription factor NF-kappaB plays a central role in regulating inflammation and apoptosis, making it a compelling target for drug development. We identified a small molecule inhibitor (ML120B) that specifically inhibits IKKbeta, an Ikappa-B kinase that regulates NF-kappaB. IKKbeta and NF-kappaB are required in vivo for prevention of TNFalpha-mediated apoptosis. ML120B sensitized mouse bone marrow progenitors and granulocytes, but not mature B cells to TNFalpha killing in vitro, and induced apoptosis in vivo in the bone marrow and spleen within 6 hours of a single oral dose. In vivo inhibition of IKKbeta with ML120B resulted in depletion of thymocytes and B cells in all stages of development in the bone marrow but did not deplete granulocytes. TNF receptor-deficient mouse thymocytes and B cells were resistant to ML120B-induced depletion in vivo. Surprisingly, surviving bone marrow granulocytes expressed TNFR1 and TNFR2 after dosing in vivo with ML120B. Our results show that inhibition of IKKbeta with a small molecule in vivo leads to rapid TNF-dependent depletion of T and B cells. This observation has several implications for potential use of IKKbeta inhibitors for the treatment of inflammatory disease and cancer.
- Published
- 2006
- Full Text
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14. A selective small molecule IkappaB Kinase beta inhibitor blocks nuclear factor kappaB-mediated inflammatory responses in human fibroblast-like synoviocytes, chondrocytes, and mast cells.
- Author
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Wen D, Nong Y, Morgan JG, Gangurde P, Bielecki A, Dasilva J, Keaveney M, Cheng H, Fraser C, Schopf L, Hepperle M, Harriman G, Jaffee BD, Ocain TD, and Xu Y
- Subjects
- Anti-Inflammatory Agents, Non-Steroidal chemistry, Chondrocytes drug effects, Chondrocytes enzymology, Chondrocytes immunology, Cytokines immunology, Dinoprostone immunology, Dose-Response Relationship, Drug, Enzyme Inhibitors chemistry, Fibroblasts drug effects, Fibroblasts enzymology, Fibroblasts immunology, HeLa Cells, Humans, Mast Cells drug effects, Mast Cells enzymology, Mast Cells immunology, Molecular Structure, NF-kappa B immunology, Signal Transduction drug effects, Synovial Membrane cytology, Anti-Inflammatory Agents, Non-Steroidal pharmacology, Connective Tissue Cells drug effects, Connective Tissue Cells enzymology, Connective Tissue Cells immunology, Enzyme Inhibitors pharmacology, I-kappa B Kinase antagonists & inhibitors, NF-kappa B antagonists & inhibitors
- Abstract
IkappaB kinase (IKK) beta is essential for inflammatory cytokine-induced activation of nuclear factor kappaB (NF-kappaB). NF-kappaB plays a pivotal role in the function of major cell types that contribute to the pathophysiological process of rheumatoid arthritis (RA). Here, we report the mechanism and the effect of the IKKbeta inhibitor N-(6-chloro-7-methoxy-9H-beta-carbolin-8-yl)-2-methylnicotinamide (ML120B), a beta-carboline derivative, on NF-kappaB signaling and gene activation in RA-relevant cell systems. ML120B is a potent, selective, reversible, and ATP-competitive inhibitor of IKKbeta with an IC50 of 60 nM when evaluated in an IkappaBalpha kinase complex assay. ML120B does not inhibit other IKK isoforms or a panel of other kinases. ML120B concentration-dependently inhibits tumor necrosis factor alpha (TNFalpha)-stimulated NF-kappaB signaling via inhibition of IkappaBalpha phosphorylation, degradation, and NF-kappaB translocation into the nucleus. For the first time, we have demonstrated that in human fibroblast-like synoviocytes, TNFalpha- or interleukin (IL)-1beta-induced monocyte chemoattractant protein-1 regulated on activation, normal T cell expressed and secreted and production is IKKbeta-dependent. In addition, for the first time, we have demonstrated that lipopolysaccharide- or peptidoglycan-induced cytokine production in human cord blood-derived mast cells is IKKbeta-dependent. In addition, in human chondrocytes, ML120B inhibited IL-1beta-induced matrix metalloproteinase production with an IC50 of approximately 1 microM. ML120B also blocked IL-1beta-induced prostaglandin E2 production. In summary, ML120B blocked numerous NF-kappaB-regulated cell responses that are involved in inflammation and destructive processes in the RA joint. Our findings support the evaluation of IKKbeta inhibitors as anti-inflammatory agents for the treatment of RA.
- Published
- 2006
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15. Small molecule inhibitors of IkappaB kinase are selectively toxic for subgroups of diffuse large B-cell lymphoma defined by gene expression profiling.
- Author
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Lam LT, Davis RE, Pierce J, Hepperle M, Xu Y, Hottelet M, Nong Y, Wen D, Adams J, Dang L, and Staudt LM
- Subjects
- Antineoplastic Agents pharmacology, Apoptosis, Carbolines pharmacology, Cell Cycle, Cell Line, Cell Line, Tumor, Cell Proliferation, Cell Survival, Dose-Response Relationship, Drug, Down-Regulation, Enzyme Inhibitors pharmacology, Genes, Dominant, Heterocyclic Compounds, 3-Ring pharmacology, Humans, I-kappa B Kinase, Inhibitory Concentration 50, L-Lactate Dehydrogenase metabolism, Leukocytes, Mononuclear cytology, NF-kappa B metabolism, Protein Serine-Threonine Kinases chemistry, Protein Serine-Threonine Kinases metabolism, Protein Structure, Tertiary, Pyridines pharmacology, Receptors, Estrogen metabolism, Tamoxifen pharmacology, Time Factors, Up-Regulation, Gene Expression Regulation, Neoplastic, Lymphoma, B-Cell drug therapy, Lymphoma, Large B-Cell, Diffuse drug therapy, Protein Serine-Threonine Kinases antagonists & inhibitors
- Abstract
Constitutive activation of the NF-kappaB pathway is required for survival of the activated B cell-like (ABC) subgroup of diffuse large B-cell lymphoma (DLBCL). Here we show that a small molecule IkappaB kinase (IKK) inhibitor, PS-1145, and related compounds are toxic for ABC DLBCL cell lines but not for cell lines derived from the other prevalent form of DLBCL, germinal center B cell-like DLBCL. Treatment of ABC lines with these inhibitors rapidly induced a series of gene expression changes that were attributable to cessation of constitutive IKK activity, similar to changes induced by acute expression of genetic inhibitors of NF-kappaB, confirming the effectiveness and specificity of this compound. Before cell death, inhibition of IKK also induced features of apoptosis and an arrest in the G1 phase of the cell cycle. To test further the specificity of this toxicity, an inducible form of NF-kappaB was created by fusing the p65 NF-kappaB subunit with the ligand-binding domain of the estrogen receptor (p65-ERD). In the presence of tamoxifen, p65-ERD reversed the toxicity of IKK inhibition and restored expression of many NF-kappaB target genes. Another subgroup of DLBCL, primary mediastinal B-cell lymphoma (PMBL), also expresses NF-kappaB target genes, and treatment of a PMBL cell line with an IKK inhibitor was toxic and induced gene expression changes of a distinct group of NF-kappaB target genes. These studies validate the NF-kappaB pathway as a promising therapeutic target in ABC DLBCL, PMBL, and other lymphomas that depend on the activity of NF-kappaB for survival and proliferation.
- Published
- 2005
16. The oxetane conformational lock of paclitaxel: structural analysis of D-secopaclitaxel.
- Author
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Boge TC, Hepperle M, Vander Velde DG, Gunn CW, Grunewald GL, and Georg GI
- Subjects
- Magnetic Resonance Spectroscopy, Molecular Conformation, Stereoisomerism, Antineoplastic Agents, Phytogenic chemistry, Paclitaxel chemistry
- Abstract
Analysis of the 1H NMR data of paclitaxel in comparison with its oxetane ring-opened analogue D-secopaclitaxel suggests that the oxetane moiety (D-ring) of paclitaxel serves as a conformational lock for the diterpene moiety and the C13 side chain.
- Published
- 1999
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17. Protection against beta-amyloid toxicity in primary neurons by paclitaxel (Taxol).
- Author
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Michaelis ML, Ranciat N, Chen Y, Bechtel M, Ragan R, Hepperle M, Liu Y, and Georg G
- Subjects
- Animals, Cell Survival drug effects, Cells, Cultured, Rats embryology, Rats, Sprague-Dawley, Amyloid beta-Peptides poisoning, Neurons drug effects, Paclitaxel pharmacology, Peptide Fragments poisoning
- Abstract
Neurofibrillary tangles in Alzheimer's disease contain aggregates of abnormally phosphorylated microtubule-associated protein tau, indicating that microtubule breakdown is a primary event in the neurodegenerative cascade. Recent studies have shown that addition to neuronal cultures of amyloid peptides found in Alzheimer's leads to abnormal phosphorylation of tau and neurofibrillary pathology. We tested the possibility that the microtubule-stabilizing drug paclitaxel (Taxol) might protect primary neurons against amyloid-induced toxicity. Neurons exposed to aggregated amyloid peptides 25-35 and 1-42 became pyknotic with degenerating neurites within 24 h. Treatment of cultures with paclitaxel either 2 h before or 2 h after addition of the peptide prevented these morphological alterations. When numbers of viable cells were determined in cultures exposed to amyloid peptide with or without paclitaxel for 24 or 96 h, the percentage of surviving cells was significantly higher in paclitaxel-treated cultures, and activation of the apoptosis-associated protease CPP32 was significantly reduced. These observations indicate that microtubule-stabilizing drugs may help slow development of the neurofibrillary pathology that leads to the loss of neuronal integrity in Alzheimer's disease.
- Published
- 1998
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18. Probing the environment of tubulin-bound paclitaxel using fluorescent paclitaxel analogues.
- Author
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Sengupta S, Boge TC, Liu Y, Hepperle M, Georg GI, and Himes RH
- Subjects
- Animals, Antineoplastic Agents, Phytogenic chemistry, Antineoplastic Agents, Phytogenic metabolism, Binding, Competitive, Cattle, Fluorescence, Macromolecular Substances, Models, Molecular, Paclitaxel analogs & derivatives, Paclitaxel chemistry, Protein Conformation, Paclitaxel metabolism, Tubulin metabolism
- Abstract
To determine the environment of different positions in the paclitaxel molecule when bound to tubulin, we have synthesized six fluorescent analogues in which a (dimethylamino)benzoyl group has been introduced into the 7- and 10-positions, and the benzoyl groups at the 2- and N- as well as the 3'-phenyl ring have been modified with dimethylamino functions. In a tubulin assembly assay, the N-m- and N-p-(dimethylamino)benzoyl derivatives had activities comparable to the activity of paclitaxel. The 2-, 3'-, and 10-analogues had slightly reduced activity, and the 7-derivative was about 5% as active as paclitaxel. On the basis of the results of studies of the effect of solvents on the fluorescence emission spectra, it is proposed that the unbound analogues form hydrogen bonds with protic solvents. But the 7- and 10-substituted analogues appear to be more affected by protic solvents than the other analogues. Previously, we studied the binding of the N-meta derivative to tubulin and microtubules [Sengupta, S., et al. (1995) Biochemistry 34, 11889-11894]. In this study, we extended the studies to include the 2-, 7-, and 10-derivatives. Similar to the N-substituted analogue, binding of the 2-derivative to tubulin was accompanied by a large blue shift, whereas a very small shift occurred when the 7- and 10-substituted derivatives bound. The 2- and N-substituted analogues bind to microtubules with an increase in fluorescence intensity over that which was observed with tubulin, whereas binding of the 7- and 10-substituted analogues was accompanied by a large quenching in fluorescence. This quenching may be due to the presence of charged residues in the protein near the 7- and 10-(dimethylamino)benzoyl groups or to pi stacking of the groups with an aromatic side chain. The presence of paclitaxel with microtubules prevented the fluorescence increase of the 2- and N-derivatives and quenching of the 7- and 10-derivatives. The difference in behavior of the fluorescent analogues upon binding to polymerized tubulin, coupled with the solvent studies on the free drugs, suggests that the 2- and N-benzoyl groups of paclitaxel bind in a hydrophobic pocket of tubulin but could participate in hydrogen bonding, and the 7- and 10-positions are in a more hydrophilic environment.
- Published
- 1997
- Full Text
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19. Preparation of phenolic paclitaxel metabolites.
- Author
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Park H, Hepperle M, Boge TC, Himes RH, and Georg GI
- Subjects
- Antineoplastic Agents, Phytogenic pharmacology, Molecular Structure, Paclitaxel chemistry, Phenol, Tubulin drug effects, Tumor Cells, Cultured, Antineoplastic Agents, Phytogenic chemical synthesis, Paclitaxel metabolism, Phenols metabolism
- Abstract
The synthesis and biological evaluation of the two known phenolic metabolites of paclitaxel are described. The C3'-phenolic metabolite 2 of paclitaxel was prepared from 7-(triethylsilyl)-baccatin III (8) and enantioenriched N-benzoyl-2-azetidinone 7. The C2-phenolic metabolite 3 was synthesized from paclitaxel (1a) via selective C2 debenzoylation and reacylation.
- Published
- 1996
- Full Text
- View/download PDF
20. Synthesis, Conformational Analysis, and Biological Evaluation of Heteroaromatic Taxanes.
- Author
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Georg GI, Harriman GC, Hepperle M, Clowers JS, Vander Velde DG, and Himes RH
- Abstract
The asymmetric syntheses of heteroaromatic 3-[(tert-butyldimethylsilyl)oxy]-2-azetidinones 12-16 via chiral ester enolate-imine cyclocondensation chemistry are described. The azetidinones contain heteroaromatic moieties which, in certain cases, contribute to a decrease in enantioselectivity due to possible alternate coordinations in the transition states. The (3R,4S)-3-[(tert-butyldimethylsilyl)oxy]-4-heteroaryl-2-azetidinones were subsequently converted to the heteroaromatic taxanes 31-36 and 43-45. Conformational analyses of the 3'-(2-pyridyl) analogue 31 and 3'-(2-furyl) analogue 43 indicate they have solution conformational preferences virtually identical to paclitaxel and docetaxel. Heteroaromatic N-acyl paclitaxel analogues 47-51 were prepared from N-debenzoylpaclitaxel via Schotten-Baumann acylation. The majority of the 14 analogues displayed good to excellent activity in a microtubule assembly assay in comparison to paclitaxel. The analogues were also tested for cytotoxicity against B16 melanoma cells. 3'-Dephenyl-3'-(2-pyridyl)paclitaxel (31), 3'-dephenyl-3'-(2-furyl)paclitaxel (34), N-BOC-3'-dephenyl-3'-(2-furyl)paclitaxel (43), 3'-dephenyl-3'-(2-furyl)-N-(hexanoyl)paclitaxel (44), and N-debenzoyl-N-(3-furoyl)paclitaxel (51) were found to be more cytotoxic than paclitaxel against this cell line. 3'-Dephenyl-3'-(4-pyridyl)paclitaxel (33) and N-debenzoyl-N-(2-furoyl)paclitaxel (50) displayed cytotoxicity against B16 melanoma cells similar to paclitaxel.
- Published
- 1996
- Full Text
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21. Airway hyperresponsiveness and asthma.
- Author
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Hargreave FE, Gibson PG, Ramsdale EH, Fitzgerald JM, and Hepperle MJ
- Subjects
- Humans, Respiratory Function Tests, Asthma physiopathology, Respiratory System physiopathology
- Published
- 1989
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