RESUMO
BACKGROUND: The mutations in the presenilin 1 gene (PSEN1) are the main cause of familial Alzheimer's disease. PSEN1 mutations affect amyloid-beta peptide production, which accumulates in the brain as senile plaque and cotton wool plaques (CWPs) and relates to other neurodegenerative disorders. Here we report the second case of the PSEN1 G266S mutation, which showed distinctive neuropathological features, including abundant CWPs. Lewy body pathology, and altered amyloid-beta production. METHOD: Using the proband's samples, we performed genetic analysis of the PSEN1, APP, MAPT, and APOE genes, histopathological and immunohistochemical analysis of the brain tissue, and biochemical analysis of Aß production in COS cells transfected with wild-type or mutant PSEN1. RESULTS: The patient presented with memory loss, abnormal behavior, and visual hallucinations. Brain scans showed reduced blood flow, mild atrophy, and white matter lesions. Genetic analysis revealed a heterozygous mutation at codon 266 (G266S) of PSEN1 and polymorphism of MAPT (Q230R). The brain had many CWPs, severe cerebral amyloid angiopathy (CAA), senile plaque, Lewy bodies, and neurites. Electron microscopy displayed myelinated fiber degeneration, mitochondrial damage, and amyloid fibrils in the white matter. The production level of Aß42 in PSEN1 G266S-transfected cells significantly increased. CONCLUSION: Our findings suggest that the PSEN1 G266S mutation may cause a heterogeneous clinical and pathological phenotype, influenced by other genetic or environmental factors.
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The pathological changes of Alzheimer's disease (AD) begin 10-20 years before clinical onset, and it is therefore desirable to identify effective methods for early diagnosis. The nasal mucosa is a target tissue for measuring AD-related biomarkers because the olfactory nerve is the only cranial nerve that is exposed to the external environment. We describe an autopsy case of rapidly advanced juvenile AD (JAD), focusing on the olfactory system. The formation of senile plaques, neurofibrillary tangles (NFTs), and neuropil threads was examined in the temporal cortex, hippocampus, olfactory bulb, and olfactory and respiratory epithelia in the bilateral olfactory clefts. Neurodegenerative changes in the olfactory and respiratory epithelia and the pathological deposition of amyloid ß42 (Aß42) and phosphorylated tau were also examined. As a result, senile plaques, NFTs, and neuropil threads were found in the temporal cortex, hippocampus, and olfactory bulb. NFTs were also found in the olfactory epithelium. Degenerated olfactory cells and their axons stained positive for phosphorylated tau. Supporting cells in the degenerated olfactory epithelium stained positive for Aß42. In conclusion, pathological biomarkers of AD were expressed in the degenerated olfactory epithelium of this JAD patient. This observation suggests that nasal samples may be useful for the diagnosis of AD.
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Nectin-2 is a transmembrane glycoprotein which is involved in the process of Ca2+-independent cell-cell adhesion. In our previous study, we have demonstrated that Nectin-2 is over-expressed in breast and ovarian cancer tissues by using gene expression analysis and immunohistochemistry. Furthermore, we discovered multiple anti-Nectin-2 fully human monoclonal antibodies which inhibited tumor growth in in vivo subcutaneous xenograft models with antibody-dependent cellular cytotoxicity (ADCC) as the principal mechanism of action. In this report, we assessed the toxicity of Y-443, a fully human IgG1/kappa anti-Nectin-2 monoclonal antibody exhibiting strong in vitro ADCC and in vivo anti-tumor activity in cynomolgus monkeys (Macaca fascicularis (Cynos)). Unexpectedly, upon administration, Y-443 induced strong thrombocytopenia through Nectin-2 expressed on Cyno platelets, presumably followed by phagocytosis in the mononuclear phagocytic system. To mitigate the adverse safety profile, we mutated the Fc region of Y-443 to reduce the Fc binding activity to Fcγ receptor I, which is the primary receptor for phagocytosis on macrophages. Moreover, we further engineered the Fc through defucosylation to maintain ADCC activity. The resultant Fc engineered antibody, termed Y-634, demonstrated diminished thrombocytopenia in Cyno toxicological studies and maintained anti-tumor activity in a mouse xenograft model. These findings suggest that Y-634 may have a therapeutic potential for the treatment of Nectin-2 positive cancers, and moreover, Fc engineering is a potential mitigation strategy to ameliorate safety liabilities in antibody induced thrombocytopenia while maintaining antibody potency.
Assuntos
Anticorpos Monoclonais/imunologia , Nectinas/antagonistas & inibidores , Nectinas/imunologia , Animais , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais/genética , Citotoxicidade Celular Dependente de Anticorpos , Linhagem Celular Tumoral , Feminino , Humanos , Fragmentos Fc das Imunoglobulinas/efeitos adversos , Fragmentos Fc das Imunoglobulinas/genética , Fragmentos Fc das Imunoglobulinas/imunologia , Macaca fascicularis , Masculino , Camundongos , Camundongos SCID , Nectinas/genética , Engenharia de Proteínas , Proteínas Recombinantes/efeitos adversos , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Trombocitopenia/etiologia , Trombocitopenia/prevenção & controle , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Climatic variabilities on millennial and longer time scales with a bipolar seesaw pattern have been documented in paleoclimatic records, but their frequencies, relationships with mean climatic state, and mechanisms remain unclear. Understanding the processes and sensitivities that underlie these changes will underpin better understanding of the climate system and projections of its future change. We investigate the long-term characteristics of climatic variability using a new ice-core record from Dome Fuji, East Antarctica, combined with an existing long record from the Dome C ice core. Antarctic warming events over the past 720,000 years are most frequent when the Antarctic temperature is slightly below average on orbital time scales, equivalent to an intermediate climate during glacial periods, whereas interglacial and fully glaciated climates are unfavourable for a millennial-scale bipolar seesaw. Numerical experiments using a fully coupled atmosphere-ocean general circulation model with freshwater hosing in the northern North Atlantic showed that climate becomes most unstable in intermediate glacial conditions associated with large changes in sea ice and the Atlantic Meridional Overturning Circulation. Model sensitivity experiments suggest that the prerequisite for the most frequent climate instability with bipolar seesaw pattern during the late Pleistocene era is associated with reduced atmospheric CO2 concentration via global cooling and sea ice formation in the North Atlantic, in addition to extended Northern Hemisphere ice sheets.
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Receptor tyrosine kinase therapies have proven to be efficacious in specific cancer patient populations; however, a significant limitation of tyrosine kinase inhibitor (TKI) treatment is the emergence of resistance mechanisms leading to a transient, partial, or complete lack of response. Combination therapies using agents with synergistic activity have potential to improve response and reduce acquired resistance. Chemoreagent or TKI treatment can lead to increased expression of hepatocyte growth factor (HGF) and/or MET, and this effect correlates with increased metastasis and poor prognosis. Despite MET's role in resistance and cancer biology, MET TKI monotherapy has yielded disappointing clinical responses. In this study, we describe the biological activity of a selective, oral MET TKI with slow off-rate and its synergistic antitumor effects when combined with an anti-HGF antibody. We evaluated the combined action of simultaneously neutralizing HGF ligand and inhibiting MET kinase activity in two cancer xenograft models that exhibit autocrine HGF/MET activation. The combination therapy results in additive antitumor activity in KP4 pancreatic tumors and synergistic activity in U-87MG glioblastoma tumors. Pharmacodynamic characterization of biomarkers that correlate with combination synergy reveal that monotherapies induce an increase in the total MET protein, whereas combination therapy significantly reduces total MET protein levels and phosphorylation of 4E-BP1. These results hold promise that dual targeting of HGF and MET by combining extracellular ligand inhibitors with intracellular MET TKIs could be an effective intervention strategy for cancer patients who have acquired resistance that is dependent on total MET protein. Mol Cancer Ther; 16(7); 1269-78. ©2017 AACR.
Assuntos
Glioblastoma/tratamento farmacológico , Fator de Crescimento de Hepatócito/genética , Inibidores de Proteínas Quinases/administração & dosagem , Proteínas Proto-Oncogênicas c-met/genética , Bibliotecas de Moléculas Pequenas/administração & dosagem , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Proteínas de Ciclo Celular , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/genética , Sinergismo Farmacológico , Glioblastoma/genética , Fator de Crescimento de Hepatócito/antagonistas & inibidores , Humanos , Camundongos , Fosfoproteínas/genética , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
To identify compounds with potent antitumor efficacy for various human cancers, we aimed to synthesize compounds that could inhibit c-mesenchymal epithelial transition factor (c-Met) and vascular endothelial growth factor receptor 2 (VEGFR2) kinases. We designed para-substituted inhibitors by using co-crystal structural information from c-Met and VEGFR2 in complex with known inhibitors. This led to the identification of compounds 3a and 3b, which were capable of suppressing both c-Met and VEGFR2 kinase activities. Further optimization resulted in pyrazolone and pyridone derivatives, which could form intramolecular hydrogen bonds to enforce a rigid conformation, thereby producing potent inhibition. One compound of particular note was the imidazo[1,2-a]pyridine derivative (26) bearing a 6-methylpyridone ring, which strongly inhibited both c-Met and VEGFR2 enzyme activities (IC50=1.9, 2.2 nM), as well as proliferation of c-Met-addicted MKN45 cells and VEGF-stimulated human umbilical vein endothelial cells (IC50=5.0, 1.8 nM). Compound 26 exhibited dose-dependent antitumor efficacy in vivo in MKN45 (treated/control ratio [T/C]=4%, po, 5mg/kg, once-daily) and COLO205 (T/C=13%, po, 15 mg/kg, once-daily) mouse xenograft models.
Assuntos
Antineoplásicos/farmacologia , Desenho de Fármacos , Compostos Heterocíclicos com 2 Anéis/farmacologia , Niacinamida/análogos & derivados , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Piridinas/farmacologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Antineoplásicos/química , Antineoplásicos/metabolismo , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Compostos Heterocíclicos com 2 Anéis/química , Compostos Heterocíclicos com 2 Anéis/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Microssomos Hepáticos/química , Microssomos Hepáticos/metabolismo , Modelos Moleculares , Estrutura Molecular , Niacinamida/química , Niacinamida/metabolismo , Niacinamida/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/metabolismo , Proteínas Proto-Oncogênicas c-met/metabolismo , Piridinas/química , Piridinas/metabolismo , Solubilidade , Relação Estrutura-Atividade , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
BACKGROUND: Nectin-2 is a Ca(2+)-independent cell-cell adhesion molecule that is one of the plasma membrane components of adherens junctions. However, little has been reported about the involvement of Nectin-2 in cancer. METHODS: To determine the expression of Nectin-2 in cancer tissues and cancer cell lines, we performed gene expression profile analysis, immunohistochemistry studies, and flow cytometry analysis. We also investigated the potential of this molecule as a target for antibody therapeutics to treat cancers by generating and characterizing an anti-Nectin-2 rabbit polyclonal antibody (poAb) and 256 fully human anti-Nectin-2 monoclonal antibodies (mAbs). In addition, we tested anti-Nectin-2 mAbs in several in vivo tumor growth inhibition models to investigate the primary mechanisms of action of the mAbs. RESULTS: In the present study, we found that Nectin-2 was over-expressed in clinical breast and ovarian cancer tissues by using gene expression profile analysis and immunohistochemistry studies. Nectin-2 was over-expressed in various cancer cell lines as well. Furthermore, the polyclonal antibody specific to Nectin-2 suppressed the in vitro proliferation of OV-90 ovarian cancer cells, which express endogenous Nectin-2 on the cell surface. The anti-Nectin-2 mAbs we generated were classified into 7 epitope bins. The anti-Nectin-2 mAbs demonstrated antibody-dependent cellular cytotoxicity (ADCC) and epitope bin-dependent features such as the inhibition of Nectin-2-Nectin-2 interaction, Nectin-2-Nectin-3 interaction, and in vitro cancer cell proliferation. A representative anti-Nectin-2 mAb in epitope bin VII, Y-443, showed anti-tumor effects against OV-90 cells and MDA-MB-231 breast cancer cells in mouse therapeutic models, and its main mechanism of action appeared to be ADCC. CONCLUSIONS: We observed the over-expression of Nectin-2 in breast and ovarian cancers and anti-tumor activity of anti-Nectin-2 mAbs via strong ADCC. These findings suggest that Nectin-2 is a potential target for antibody therapy against breast and ovarian cancers.
Assuntos
Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Monoclonais Humanizados/farmacologia , Antineoplásicos/farmacologia , Neoplasias da Mama/imunologia , Moléculas de Adesão Celular/imunologia , Neoplasias Ovarianas/imunologia , Animais , Anticorpos Monoclonais Humanizados/administração & dosagem , Citotoxicidade Celular Dependente de Anticorpos/efeitos dos fármacos , Citotoxicidade Celular Dependente de Anticorpos/imunologia , Antineoplásicos/administração & dosagem , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Epitopos/imunologia , Feminino , Expressão Gênica , Humanos , Camundongos , Nectinas , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Ligação Proteica/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
For the purpose of discovering novel type-II inhibitors of vascular endothelial growth factor receptor 2 (VEGFR2) kinase, we designed and synthesized 5,6-fused heterocyclic compounds bearing a anilide group. A co-crystal structure analysis of imidazo[1,2-b]pyridazine derivative 2 with VEGFR2 revealed that the N1-nitrogen of imidazo[1,2-b]pyridazine core interacts with the backbone NH group of Cys919. To retain this essential interaction, we designed a series of imidazo[1,2-a]pyridine, [1,2,4]triazolo[1,5-a]pyridine, thiazolo[5,4-b]pyridine, and 1,3-benzothiazole derivatives maintaining a ring nitrogen as hydrogen bond acceptor (HBA) at the corresponding position. All compounds thus designed displayed strong inhibitory activity against VEGFR2 kinase, and the [1,2,4]triazolo[1,5-a]pyridine 13d displayed favorable physicochemical properties. Furthermore, 13d inhibited VEGFR2 kinase with slow dissociation kinetics and also inhibited platelet-derived growth factor receptor (PDGFR) kinases. Oral administration of 13d showed potent anti-tumor efficacy in DU145 and A549 xenograft models in nude mice.
Assuntos
Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacologia , Piridinas/síntese química , Piridinas/farmacologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Desenho de Fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Cinética , Neoplasias Pulmonares/tratamento farmacológico , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Estrutura Molecular , Neoplasias da Próstata/tratamento farmacológico , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacocinética , Piridinas/química , Piridinas/farmacocinética , Distribuição Aleatória , Relação Estrutura-Atividade , Triazóis/síntese química , Triazóis/química , Triazóis/farmacologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/química , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The c-Met receptor tyrosine kinase and its ligand, hepatocyte growth factor (HGF), are dysregulated in a wide variety of human cancers and are linked with tumorigenesis and metastatic progression. VEGF also plays a key role in tumor angiogenesis and progression by stimulating the proangiogenic signaling of endothelial cells via activation of VEGF receptor tyrosine kinases (VEGFR). Therefore, inhibiting both HGF/c-Met and VEGF/VEGFR signaling may provide a novel therapeutic approach for treating patients with a broad spectrum of tumors. Toward this goal, we generated and characterized T-1840383, a small-molecule kinase inhibitor that targets both c-Met and VEGFRs. T-1840383 inhibited HGF-induced c-Met phosphorylation and VEGF-induced VEGFR-2 phosphorylation in cancer epithelial cells and vascular endothelial cells, respectively. It also inhibited constitutively activated c-Met phosphorylation in c-met-amplified cancer cells, leading to suppression of cell proliferation. In addition, T-1840383 potently blocked VEGF-dependent proliferation and capillary tube formation of endothelial cells. Following oral administration, T-1840383 showed potent antitumor efficacy in a wide variety of human tumor xenograft mouse models, along with reduction of c-Met phosphorylation levels and microvessel density within tumor xenografts. These results suggest that the efficacy of T-1840383 is produced by direct effects on tumor cell growth and by an antiangiogenic mechanism. Furthermore, T-1840383 showed profound antitumor activity in a gastric tumor peritoneal dissemination model. Collectively, our findings indicate the therapeutic potential of targeting both c-Met and VEGFRs simultaneously with a single small-molecule inhibitor for the treatment of human cancers.
Assuntos
Fator de Crescimento de Hepatócito/genética , Compostos Heterocíclicos com 2 Anéis/administração & dosagem , Niacinamida/análogos & derivados , Inibidores de Proteínas Quinases/administração & dosagem , Proteínas Proto-Oncogênicas c-met/genética , Neoplasias Gástricas/tratamento farmacológico , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Inibidores da Angiogênese/administração & dosagem , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/patologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Fator de Crescimento de Hepatócito/antagonistas & inibidores , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Camundongos , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/genética , Neovascularização Patológica/patologia , Niacinamida/administração & dosagem , Proteínas Proto-Oncogênicas c-met/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacos , Neoplasias Gástricas/irrigação sanguínea , Neoplasias Gástricas/patologia , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Vascular endothelial growth factor (VEGF) plays important roles in tumor angiogenesis, and the inhibition of its signaling pathway is considered an effective therapeutic option for the treatment of cancer. In this study, we describe the design, synthesis, and biological evaluation of 2-acylamino-6-phenoxy-imidazo[1,2-b]pyridazine derivatives. Hybridization of two distinct imidazo[1,2-b]pyridazines 1 and 2, followed by optimization led to the discovery of N-[5-({2-[(cyclopropylcarbonyl)amino]imidazo[1,2-b]pyridazin-6-yl}oxy)-2-methylphenyl]-1,3-dimethyl-1H-pyrazole-5-carboxamide (23a, TAK-593) as a highly potent VEGF receptor 2 kinase inhibitor with an IC50 value of 0.95 nM. The compound 23a strongly suppressed proliferation of VEGF-stimulated human umbilical vein endothelial cells with an IC50 of 0.30 nM. Kinase selectivity profiling revealed that 23a inhibited platelet-derived growth factor receptor kinases as well as VEGF receptor kinases. Oral administration of 23a at 1 mg/kg bid potently inhibited tumor growth in a mouse xenograft model using human lung adenocarcinoma A549 cells (T/C=8%).
Assuntos
Aminoimidazol Carboxamida/análogos & derivados , Inibidores de Proteínas Quinases/farmacologia , Pirazóis/farmacologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Aminoimidazol Carboxamida/química , Aminoimidazol Carboxamida/farmacologia , Animais , Modelos Animais de Doenças , Feminino , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Macaca fascicularis , Masculino , Camundongos , Camundongos Endogâmicos AKR , Camundongos Nus , Modelos Moleculares , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacocinética , Pirazóis/química , Pirazóis/farmacocinética , Ratos , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/química , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
In order to develop potent and selective focal adhesion kinase (FAK) inhibitors, synthetic studies on pyrazolo[4,3-c][2,1]benzothiazines targeted for the FAK allosteric site were carried out. Based on the X-ray structural analysis of the co-crystal of the lead compound, 8-(4-ethylphenyl)-5-methyl-1,5-dihydropyrazolo[4,3-c][2,1]benzothiazine 4,4-dioxide 1 with FAK, we designed and prepared 1,5-dimethyl-1,5-dihydropyrazolo[4,3-c][2,1]benzothiazin derivatives which selectively inhibited kinase activity of FAK without affecting seven other kinases. The optimized compound, N-(4-tert-butylbenzyl)-1,5-dimethyl-1,5-dihydropyrazolo[4,3-c][2,1]benzothiazin-8-amine 4,4-dioxide 30 possessed significant FAK kinase inhibitory activities both in cell-free (IC50=0.64µM) and in cellular assays (IC50=7.1µM). These results clearly demonstrated a potential of FAK allosteric inhibitors as antitumor agents.
Assuntos
Antineoplásicos/química , Óxidos S-Cíclicos/química , Proteína-Tirosina Quinases de Adesão Focal/antagonistas & inibidores , Compostos Heterocíclicos com 3 Anéis/química , Inibidores de Proteínas Quinases/química , Tiazinas/química , Sítio Alostérico , Antineoplásicos/síntese química , Antineoplásicos/metabolismo , Sítios de Ligação , Cristalografia por Raios X , Óxidos S-Cíclicos/síntese química , Óxidos S-Cíclicos/metabolismo , Avaliação Pré-Clínica de Medicamentos , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Compostos Heterocíclicos com 3 Anéis/síntese química , Compostos Heterocíclicos com 3 Anéis/metabolismo , Simulação de Acoplamento Molecular , Ligação Proteica , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Estrutura Terciária de Proteína , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Relação Estrutura-Atividade , Tiazinas/síntese química , Tiazinas/metabolismoRESUMO
We recently reported that TAK-593, a novel imidazo[1,2-b]pyridazine derivative, is a highly potent and selective inhibitor of the vascular endothelial growth factor (VEGF) and platelet derived growth factor (PDGF) receptor tyrosine kinase families. Moreover, TAK-593 exhibits a uniquely long-acting inhibitory profile towards VEGF receptor 2 (VEGFR2) and PDGF receptor ß (PDGFRß). In this study, we demonstrated that TAK-593 potently inhibits VEGF- and PDGF-stimulated cellular phosphorylation and proliferation of human umbilical vein endothelial cells and human coronary artery smooth muscle cells. TAK-593 also potently inhibits VEGF-induced tube formation of endothelial cells co-cultured with fibroblasts. Oral administration of TAK-593 exhibited strong anti-tumor effects against various human cancer xenografts along with good tolerability despite a low level of plasma exposure. Even after the blood and tissue concentrations of TAK-593 decreased below the detectable limit, a pharmacodynamic marker (phospho VEGFR2) was almost completely suppressed, indicating that its long duration of enzyme inhibition might contribute to the potent activity of TAK-593. Immunohistochemical staining indicated that TAK-593 showed anti-proliferative and pro-apoptotic effects on tumors along with a decrease of vessel density and inhibition of pericyte recruitment to microvessels in vivo. Furthermore, dynamic contrast-enhanced magnetic resonance imaging revealed that TAK-593 reduced tumor vessel permeability prior to the onset of anti-tumor activity. In conclusion, TAK-593 is an extremely potent VEGFR/PDGFR kinase inhibitor whose potent anti-angiogenic activity suggests therapeutic potential for the treatment of solid tumors.
Assuntos
Inibidores da Angiogênese/uso terapêutico , Antineoplásicos/uso terapêutico , Compostos Azabicíclicos/uso terapêutico , Neoplasias/tratamento farmacológico , Pirazóis/uso terapêutico , Receptores do Fator de Crescimento Derivado de Plaquetas/antagonistas & inibidores , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Apoptose/efeitos dos fármacos , Compostos Azabicíclicos/farmacologia , Permeabilidade Capilar/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Humanos , Camundongos , Camundongos Nus , Camundongos SCID , Neoplasias/irrigação sanguínea , Neovascularização Patológica/tratamento farmacológico , Pirazóis/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Focal adhesion kinase (FAK) regulates cell survival and proliferation pathways. Here we report the discovery of a highly selective series of 1,5-dihydropyrazolo[4,3-c][2,1]benzothiazines that demonstrate a novel mode of allosteric inhibition of FAK. These compounds showed slow dissociation from unphosphorylated FAK and were noncompetitive with ATP after long preincubation. Co-crystal structural analysis revealed that the compounds target a novel allosteric site within the C-lobe of the kinase domain, which induces disruption of ATP pocket formation leading to the inhibition of kinase activity. The potency of allosteric inhibition was reduced by phosphorylation of FAK. Coupled SAR analysis revealed that N-substitution of the fused pyrazole is critical to achieve allosteric binding and high selectivity among kinases.
Assuntos
Descoberta de Drogas , Proteína-Tirosina Quinases de Adesão Focal/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Pirazóis/farmacologia , Tiazinas/farmacologia , Regulação Alostérica/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Pirazóis/síntese química , Pirazóis/química , Relação Estrutura-Atividade , Tiazinas/síntese química , Tiazinas/químicaRESUMO
The vascular endothelial growth factor (VEGF) signaling pathway has been implicated in tumor angiogenesis, and inhibition of the VEGF pathway is considered an efficacious method for treating cancer. Herein, we describe synthetic studies of imidazo[1,2-b]pyridazine derivatives as VEGF receptor 2 (VEGFR2) kinase inhibitors. The imidazo[1,2-b]pyridazine scaffold was designed and synthesized as a hinge binder according to the previously reported crystal structure of pyrrolo[3,2-d]pyrimidine 1 with VEGFR2. Structure-activity relationship studies revealed that meta-substituted 6-phenoxy-imidazo[1,2-b]pyridazine derivatives had potent affinity for VEGFR2. In particular, N-[3-(imidazo[1,2-b]pyridazin-6-yloxy)phenyl]-3-(trifluoromethyl)benzamide (6b) exhibited strong inhibitory activity against VEGFR2 with an IC(50) value of 7.1 nM, and it inhibited platelet-derived growth factor receptor ß kinase with an IC(50) value of 15 nM.
Assuntos
Benzamidas/química , Benzamidas/farmacologia , Imidazóis/química , Imidazóis/farmacologia , Piridazinas/química , Piridazinas/farmacologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Benzamidas/síntese química , Linhagem Celular Tumoral , Desenho de Fármacos , Humanos , Imidazóis/síntese química , Masculino , Camundongos , Modelos Moleculares , Neoplasias da Próstata/tratamento farmacológico , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Piridazinas/síntese química , Relação Estrutura-Atividade , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Diffraction-enhanced imaging (DEI) is a phase-contrast X-ray imaging technique suitable for visualizing light-element materials. The method also enables observations of sample-containing regions with large density gradients. In this study a cryogenic imaging technique was developed for DEI-enabled measurements at low temperature from 193 K up to room temperature with a deviation of 1 K. Structure-II air hydrate and structure-I carbon dioxide (CO(2)) hydrate were examined to assess the performance of this cryogenic DEI technique. It was shown that this DEI technique could image gas hydrate coexisting with ice and gas bubbles with a density resolution of about 0.01 g cm(-3) and a wide dynamic density range of about 1.60 g cm(-3). In addition, this method may be a way to make temperature-dependent measurements of physical properties such as density.
RESUMO
We recently reported that compound 20d (comp.20d), a novel pyrrolo[3, 2-d]pyrimidine derivative, is a potent and selective inhibitor of tumor angiogenesis-related kinases, including vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR). In this study, we show that comp.20d potently blocks the VEGF- and PDGF-stimulated cellular phosphorylation (IC(50) = 2.5 and 3.6 nM, respectively) and proliferation of HUVECs and human coronary artery smooth muscle cells with IC(50) values of 2.8 and 9.6 nM, respectively, and potently inhibits the VEGF-induced tube formation of endothelial cells cocultured with fibroblasts (IC(50) = 3.3 nM). Given orally twice daily, comp.20d at the doses of 1.5-6 mg/kg showed antitumor effects in mice bearing various human cancer xenografts. Consistent with the anti-angiogenic mechanism of action, histological examination of tumors from comp. 20d-treated mice indicated a decrease in microvessel density and inhibition of pericyte recruitment to microvessels, and these were concomitant with decreased interstitial fluid pressure that allowed for therapeutic intratumoral uptake of CPT-11 (irinotecan hydrochloride). In conclusion, comp.20d is an extremely potent inhibitor of VEGFR/PDGFR kinases whose activities suggest therapeutic potential for the treatment of solid tumors that rely on angiogenesis for their survival.
Assuntos
Inibidores da Angiogênese/uso terapêutico , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Neoplasias/irrigação sanguínea , Neoplasias/tratamento farmacológico , Compostos de Fenilureia/uso terapêutico , Receptores do Fator de Crescimento Derivado de Plaquetas/antagonistas & inibidores , Receptores de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Linhagem Celular Tumoral , Células Cultivadas , Humanos , Camundongos , Camundongos Nus , Camundongos SCID , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
We present a straightforward process for the discovery of novel back pocket-binding fragment molecules against protein tyrosine kinases. The approach begins by screening against the nonphosphorylated target kinase with subsequent counterscreening of hits against the phosphorylated enzyme. Back pocket-binding fragments are inactive against the phosphorylated kinase. Fragment molecules are of insufficient size to span both regions of the ATP binding pocket; thus, the outcome is binary (back pocket-binding or hinge-binding). Next, fragments with the appropriate binding profile are assayed in combination with a known hinge-binding fragment and subsequently with a known back pocket-binding fragment. Confirmation of back pocket-binding by Yonetani-Theorell plot analysis progresses candidate fragments to crystallization trials. The method is exemplified by a fragment screening campaign against vascular endothelial growth factor receptor 2, and a novel back pocket-binding fragment is presented.
RESUMO
Abnormal distributions of transition metals inside the brain are potential diagnostic markers for several central nervous system diseases, including Alzheimer's disease (AD), Parkinson's disease, dementia with Lewy bodies (DLB), bipolar disorders and depression. To further explore this possibility, the total concentrations of iron, zinc, copper, manganese, aluminum, chromium and cadmium were measured in post-mortem hippocampus and amygdala tissues taken from AD, DLB and Control patients. A statistically significant near fifty percent reduction in the total copper levels of AD patients was observed in both the hippocampus and amygdala. The statistical power of the hippocampus and amygdala copper analysis was found to be 86 and 74% respectively. No statistically significant deviations in the total metal concentrations were found for zinc, manganese, chromium or aluminum. Iron was found to be increased by 38% in AD amygdala tissues, but was unchanged in AD hippocampus tissues. Accounting for differences in tissue water content, as a function of both tissue type and disease state, revealed more consistencies with previous literature. To aid in the design of future experiments, the effect sizes for all tissue types and metals studied are also presented.