RESUMO
Purpose Preclinical evidence suggests the importance of Janus activating kinase (JAK) and TANK-binding kinase 1 (TBK1) in pancreatic ductal adenocarcinoma (PDAC). We evaluated the safety and efficacy of momelotinib (MMB), a JAK1/2 inhibitor with additional activity against TBK1, plus albumin-bound paclitaxel + gemcitabine (nab-P + G), in patients with previously untreated metastatic PDAC. Experimental Design Patients were enrolled into five cohorts of increasing doses of MMB between 100 and 200 mg administered once or twice daily in combination with nab-P + G in 28-day cycles to determine maximum tolerated dose (MTD). Safety, efficacy, pharmacokinetics, and pharmacodynamics were assessed for all patients. Results Twenty-five patients were enrolled. Dose-limiting toxicities of Grade 3 diarrhea occurred in 1 patient each in the 100 and 200 mg MMB once-daily dose groups. MTD was not reached. The 200 mg MMB twice-daily was the maximum administered dose. Objective response rate was 28% (all partial responses), and 13 (52%) patients had a best response of stable disease. The most common adverse events (AEs) were fatigue (80%), nausea (76%), and anemia (68%). Grade 3 or 4 AEs, most commonly neutropenia (32%), were reported by 88% of patients, of which 44% were considered related to MMB. Pharmacokinetic analyses showed MMB concentrations were too low for TBK1 inhibition. Conclusions MMB was safe and well tolerated in combination with nab-P + G. As no OS or PFS benefit vs nab-P + G was apparent in context of suboptimal engagement of the target TBK1, this study does not support further development of MMB as a first-line therapy in pancreatic cancer.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Ductal Pancreático/tratamento farmacológico , Janus Quinase 1/antagonistas & inibidores , Janus Quinase 2/antagonistas & inibidores , Neoplasias Pancreáticas/tratamento farmacológico , Albuminas/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Benzamidas/administração & dosagem , Carcinoma Ductal Pancreático/enzimologia , Carcinoma Ductal Pancreático/secundário , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Feminino , Seguimentos , Humanos , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Paclitaxel/administração & dosagem , Neoplasias Pancreáticas/enzimologia , Neoplasias Pancreáticas/patologia , Prognóstico , Pirimidinas/administração & dosagem , Distribuição Tecidual , GencitabinaRESUMO
Recombinant human tumor necrosis factor-α-related apoptosis inducing ligand (TRAIL), agonistic monoclonal antibodies to TRAIL receptors, and small molecule TRAIL receptor agonists are in various stages of preclinical and early phase clinical testing as potential anticancer drugs. Accordingly, there is substantial interest in understanding factors that affect sensitivity to these agents. In the present study we observed that the poly(ADP-ribose) polymerase (PARP) inhibitors olaparib and veliparib sensitize the myeloid leukemia cell lines ML-1 and K562, the ovarian cancer line PEO1, non-small cell lung cancer line A549, and a majority of clinical AML isolates, but not normal marrow, to TRAIL. Further analysis demonstrated that PARP inhibitor treatment results in activation of the FAS and TNFRSF10B (death receptor 5 (DR5)) promoters, increased Fas and DR5 mRNA, and elevated cell surface expression of these receptors in sensitized cells. Chromatin immunoprecipitation demonstrated enhanced binding of the transcription factor Sp1 to the TNFRSF10B promoter in the presence of PARP inhibitor. Knockdown of PARP1 or PARP2 (but not PARP3 and PARP4) not only increased expression of Fas and DR5 at the mRNA and protein level, but also recapitulated the sensitizing effects of the PARP inhibition. Conversely, Sp1 knockdown diminished the PARP inhibitor effects. In view of the fact that TRAIL is part of the armamentarium of natural killer cells, these observations identify a new facet of PARP inhibitor action while simultaneously providing the mechanistic underpinnings of a novel therapeutic combination that warrants further investigation.
Assuntos
Apoptose/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Neoplasias/tratamento farmacológico , Inibidores de Poli(ADP-Ribose) Polimerases , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/biossíntese , Receptor fas/biossíntese , Humanos , Células K562 , Neoplasias/genética , Neoplasias/metabolismo , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/metabolismo , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/genética , Elementos de Resposta , Fator de Transcrição Sp1/genética , Fator de Transcrição Sp1/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF/farmacologia , Receptor fas/genéticaAssuntos
Linfoma Folicular/tratamento farmacológico , Linfoma Folicular/mortalidade , Purinas/administração & dosagem , Quinazolinonas/administração & dosagem , Anticorpos Monoclonais Murinos/administração & dosagem , Anticorpos Monoclonais Murinos/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Ciclofosfamida/administração & dosagem , Ciclofosfamida/efeitos adversos , Intervalo Livre de Doença , Doxorrubicina/administração & dosagem , Doxorrubicina/efeitos adversos , Feminino , Humanos , Linfoma Folicular/patologia , Masculino , Prednisona/administração & dosagem , Prednisona/efeitos adversos , Purinas/efeitos adversos , Quinazolinonas/efeitos adversos , Recidiva , Rituximab , Taxa de Sobrevida , Vincristina/administração & dosagem , Vincristina/efeitos adversosRESUMO
The mammalian target of rapamycin (mTOR) plays crucial roles in proliferative and antiapoptotic signaling in lymphoid malignancies. Rapamycin analogs, which are allosteric mTOR complex 1 (mTORC1) inhibitors, are active in mantle cell lymphoma and other lymphoid neoplasms, but responses are usually partial and short-lived. In the present study we compared the effects of rapamycin with the dual mTORC1/mTORC2 inhibitor OSI-027 in cell lines and clinical samples representing divers lymphoid malignancies. In contrast to rapamycin, OSI-027 markedly diminished proliferation and induced apoptosis in a variety of lymphoid cell lines and clinical samples, including specimens of B-cell acute lymphocytic leukemia (ALL), mantle cell lymphoma, marginal zone lymphoma and Sezary syndrome. Additional analysis demonstrated that OSI-027-induced apoptosis depended on transcriptional activation of the PUMA and BIM genes. Overexpression of Bcl-2, which neutralizes Puma and Bim, or loss of procaspase 9 diminished OSI-027-induced apoptosis in vitro. Moreover, OSI-027 inhibited phosphorylation of mTORC1 and mTORC2 substrates, up-regulated Puma, and induced regressions in Jeko xenografts. Collectively, these results not only identify a pathway that is critical for the cytotoxicity of dual mTORC1/mTORC2 inhibitors, but also suggest that simultaneously targeting mTORC1 and mTORC2 might be an effective anti-lymphoma strategy in vivo.
Assuntos
Proteínas Reguladoras de Apoptose/antagonistas & inibidores , Apoptose/efeitos dos fármacos , Imidazóis/farmacologia , Linfoma/patologia , Proteínas/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Fatores de Transcrição/antagonistas & inibidores , Triazinas/farmacologia , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Western Blotting , Proliferação de Células/efeitos dos fármacos , Humanos , Imunoprecipitação , Imunossupressores/farmacologia , Linfoma/tratamento farmacológico , Linfoma/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina , Complexos Multiproteicos , Fosforilação/efeitos dos fármacos , Proteínas/genética , Proteínas/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , Reação em Cadeia da Polimerase em Tempo Real , Sirolimo/farmacologia , Serina-Treonina Quinases TOR , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Células Tumorais CultivadasRESUMO
Novel combinations targeting new molecular vulnerabilities are needed to improve the outcome of patients with acute myeloid leukemia. We recently identified WEE1 kinase as a novel target in leukemias. To identify genes that are synthetically lethal with WEE1 inhibition, we performed a short interfering RNA screen directed against cell cycle and DNA repair genes during concurrent treatment with the WEE1 inhibitor MK1775. CHK1 and ATR, genes encoding two replication checkpoint kinases, were among the genes whose silencing enhanced the effects of WEE1 inhibition most, whereas CDK2 short interfering RNA antagonized MK1775 effects. Building on this observation, we examined the impact of combining MK1775 with selective small molecule inhibitors of CHK1, ATR and cyclin-dependent kinases. The CHK1 inhibitor MK8776 sensitized acute myeloid leukemia cell lines and primary leukemia specimens to MK1775 ex vivo, whereas smaller effects were observed with the MK1775/MK8776 combination in normal myeloid progenitors. The ATR inhibitor VE-821 likewise enhanced the antiproliferative effects of MK1775, whereas the cyclin-dependent kinase inhibitor roscovitine antagonized MK1775. Further studies showed that MK8776 enhanced MK1775-mediated activation of the ATR/CHK1 pathway in acute leukemia cell lines and ex vivo. These results indicate that combined cell cycle checkpoint interference with MK1775/MK8776 warrants further investigation as a potential treatment for acute myeloid leukemia.
Assuntos
Proteínas de Ciclo Celular/genética , Leucemia Mieloide Aguda/genética , Proteínas Nucleares/genética , Inibidores de Proteínas Quinases/farmacologia , Proteínas Quinases/genética , Proteínas Tirosina Quinases/genética , Apoptose/efeitos dos fármacos , Apoptose/genética , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Quinase 1 do Ponto de Checagem , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Perfilação da Expressão Gênica , Inativação Gênica , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/metabolismo , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Quinases/metabolismo , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/metabolismo , Pirazóis/farmacologia , Pirimidinas/farmacologia , Pirimidinonas , Interferência de RNA , RNA Interferente Pequeno/genética , Transdução de Sinais , Ensaio Tumoral de Célula-TroncoRESUMO
OBJECTIVE: To improve problem list documentation and care quality. MATERIALS AND METHODS: We developed algorithms to infer clinical problems a patient has that are not recorded on the coded problem list using structured data in the electronic health record (EHR) for 12 clinically significant heart, lung, and blood diseases. We also developed a clinical decision support (CDS) intervention which suggests adding missing problems to the problem list. We evaluated the intervention at 4 diverse healthcare systems using 3 different EHRs in a randomized trial using 3 predetermined outcome measures: alert acceptance, problem addition, and National Committee for Quality Assurance Healthcare Effectiveness Data and Information Set (NCQA HEDIS) clinical quality measures. RESULTS: There were 288 832 opportunities to add a problem in the intervention arm and the problem was added 63 777 times (acceptance rate 22.1%). The intervention arm had 4.6 times as many problems added as the control arm. There were no significant differences in any of the clinical quality measures. DISCUSSION: The CDS intervention was highly effective at improving problem list completeness. However, the improvement in problem list utilization was not associated with improvement in the quality measures. The lack of effect on quality measures suggests that problem list documentation is not directly associated with improvements in quality measured by National Committee for Quality Assurance Healthcare Effectiveness Data and Information Set (NCQA HEDIS) quality measures. However, improved problem list accuracy has other benefits, including clinical care, patient comprehension of health conditions, accurate CDS and population health, and for research. CONCLUSION: An EHR-embedded CDS intervention was effective at improving problem list completeness but was not associated with improvement in quality measures.
Assuntos
Sistemas de Apoio a Decisões Clínicas , Humanos , Registros Eletrônicos de Saúde , Qualidade da Assistência à SaúdeRESUMO
PURPOSE: A phase Ib study (1604) was conducted to evaluate the safety and efficacy of GS-5829, an oral bromodomain and extraterminal inhibitor, alone and in combination with enzalutamide in metastatic castration-resistant prostate cancer (mCRPC). A phase I study (1599) in solid tumors/lymphoma was also conducted. PATIENTS AND METHODS: Men with confirmed mCRPC and disease progression despite abiraterone and/or enzalutamide treatment were enrolled in a 3 + 3 dose escalation paradigm starting at 2 mg daily with GS-5829 alone and in combination with 160 mg daily enzalutamide. The primary efficacy endpoint was nonprogression rate at week 24; secondary endpoints included prostate-specific antigen reduction from baseline, progression-free survival, and GS-5829 pharmacokinetics (PK). PK and safety were also evaluated in Study 1599. RESULTS: Thirty-one men, with a median of five prior regimens, received at least 1 dose of study drug in Study 1604. Treatment-emergent adverse events (TEAE) were reported in 94% of patients; 16% discontinued for TEAEs. There were no dose-dependent increases in the AUCtau or Cmax after once-daily administration of GS-5829 2 to 9 mg, and biomarkers CCR2 inhibition and HEXIM1 induction were increased only at higher doses of monotherapy. A high degree of interpatient variability existed across all doses in PK and pharmacodynamic parameters. The proportion with nonprogression at week 24, estimated by Kaplan-Meier model, was 25% (95% confidence interval, 10-42) for all treated patients. CONCLUSIONS: GS-5829 was generally tolerated but demonstrated limited efficacy and lack of dose proportional increases in plasma concentrations in patients with mCRPC.
Assuntos
Neoplasias de Próstata Resistentes à Castração , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Benzamidas , Humanos , Masculino , Nitrilas/uso terapêutico , Feniltioidantoína , Antígeno Prostático Específico , Neoplasias de Próstata Resistentes à Castração/patologia , Proteínas de Ligação a RNA , Fatores de Transcrição , Resultado do TratamentoRESUMO
OBJECTIVE: To develop and test an accurate deep learning model for predicting new onset delirium in hospitalized adult patients. METHODS: Using electronic health record (EHR) data extracted from a large academic medical center, we developed a model combining long short-term memory (LSTM) and machine learning to predict new onset delirium and compared its performance with machine-learning-only models (logistic regression, random forest, support vector machine, neural network, and LightGBM). The labels of models were confusion assessment method (CAM) assessments. We evaluated models on a hold-out dataset. We calculated Shapley additive explanations (SHAP) measures to gauge the feature impact on the model. RESULTS: A total of 331 489 CAM assessments with 896 features from 34 035 patients were included. The LightGBM model achieved the best performance (AUC 0.927 [0.924, 0.929] and F1 0.626 [0.618, 0.634]) among the machine learning models. When combined with the LSTM model, the final model's performance improved significantly (P = .001) with AUC 0.952 [0.950, 0.955] and F1 0.759 [0.755, 0.765]. The precision value of the combined model improved from 0.497 to 0.751 with a fixed recall of 0.8. Using the mean absolute SHAP values, we identified the top 20 features, including age, heart rate, Richmond Agitation-Sedation Scale score, Morse fall risk score, pulse, respiratory rate, and level of care. CONCLUSION: Leveraging LSTM to capture temporal trends and combining it with the LightGBM model can significantly improve the prediction of new onset delirium, providing an algorithmic basis for the subsequent development of clinical decision support tools for proactive delirium interventions.
Assuntos
Delírio , Registros Eletrônicos de Saúde , Adulto , Humanos , Memória de Curto Prazo , Aprendizado de Máquina , Redes Neurais de Computação , Delírio/diagnósticoRESUMO
OBJECTIVES: Complex interventions with multiple components and behavior change strategies are increasingly implemented as a form of clinical decision support (CDS) using native electronic health record functionality. Objectives of this study were, therefore, to (1) identify the proportion of randomized controlled trials with CDS interventions that were complex, (2) describe common gaps in the reporting of complexity in CDS research, and (3) determine the impact of increased complexity on CDS effectiveness. MATERIALS AND METHODS: To assess CDS complexity and identify reporting gaps for characterizing CDS interventions, we used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting tool for complex interventions. We evaluated the effect of increased complexity using random-effects meta-analysis. RESULTS: Most included studies evaluated a complex CDS intervention (76%). No studies described use of analytical frameworks or causal pathways. Two studies discussed use of theory but only one fully described the rationale and put it in context of a behavior change. A small but positive effect (standardized mean difference, 0.147; 95% CI, 0.039-0.255; P < .01) in favor of increasing intervention complexity was observed. DISCUSSION: While most CDS studies should classify interventions as complex, opportunities persist for documenting and providing resources in a manner that would enable CDS interventions to be replicated and adapted. Unless reporting of the design, implementation, and evaluation of CDS interventions improves, only slight benefits can be expected. CONCLUSION: Conceptualizing CDS as complex interventions may help convey the careful attention that is needed to ensure these interventions are contextually and theoretically informed.
Assuntos
Sistemas de Apoio a Decisões Clínicas , Ensaios Clínicos Controlados Aleatórios como AssuntoAssuntos
Transfusão de Plaquetas/efeitos adversos , Plaquetoferese/efeitos adversos , Oclusão da Veia Retiniana/diagnóstico , Oclusão da Veia Retiniana/etiologia , Angiofluoresceinografia , Humanos , Masculino , Pessoa de Meia-Idade , Oclusão da Veia Retiniana/patologia , Fatores de Risco , Trombose/diagnóstico , Trombose/etiologia , Trombose/patologiaRESUMO
Although inhibitors of the kinases CHK1, ATR, and WEE1 are undergoing clinical testing, it remains unclear how these three classes of agents kill susceptible cells and whether they utilize the same cytotoxic mechanism. Here we observed that CHK1 inhibition induces apoptosis in a subset of acute leukemia cell lines in vitro, including TP53-null acute myeloid leukemia (AML) and BCR/ABL-positive acute lymphoid leukemia (ALL), and inhibits leukemic colony formation in clinical AML samples ex vivo. In further studies, downregulation or inhibition of CHK1 triggered signaling in sensitive human acute leukemia cell lines that involved CDK2 activation followed by AP1-dependent TNF transactivation, TNFα production, and engagement of a TNFR1- and BID-dependent apoptotic pathway. AML lines that were intrinsically resistant to CHK1 inhibition exhibited high CHK1 expression and were sensitized by CHK1 downregulation. Signaling through this same CDK2-AP1-TNF cytotoxic pathway was also initiated by ATR or WEE1 inhibitors in vitro and during CHK1 inhibitor treatment of AML xenografts in vivo. Collectively, these observations not only identify new contributors to the antileukemic cell action of CHK1, ATR, and WEE1 inhibitors, but also delineate a previously undescribed pathway leading from aberrant CDK2 activation to death ligand-induced killing that can potentially be exploited for acute leukemia treatment. SIGNIFICANCE: This study demonstrates that replication checkpoint inhibitors can kill AML cells through a pathway involving AP1-mediated TNF gene activation and subsequent TP53-independent, TNFα-induced apoptosis, which can potentially be exploited clinically.
Assuntos
Quinase 2 Dependente de Ciclina/antagonistas & inibidores , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Pirazinas/farmacologia , Pirazóis/farmacologia , Fator de Necrose Tumoral alfa/metabolismo , Animais , Apoptose , Proliferação de Células , Feminino , Humanos , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Células Tumorais Cultivadas , Fator de Necrose Tumoral alfa/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Chemical genetics, or the specific modulation of cellular systems by small molecules, has complemented classical genetic analysis throughout the history of neurobiology. We outline several of its contributions to the understanding of ion channel biology, heat and cold signal transduction, sleep and diurnal rhythm regulation, effects of immunophilin ligands, and cell surface oligosaccharides with respect to neurobiology.
Assuntos
Biologia Molecular/métodos , Técnicas de Sonda Molecular/tendências , Neurobiologia/métodos , Animais , Ritmo Circadiano/fisiologia , Humanos , Imunofilinas , Canais Iônicos/fisiologia , Proteínas de Membrana/efeitos dos fármacos , Proteínas de Membrana/metabolismo , Biologia Molecular/tendências , Neurobiologia/tendências , Sensação Térmica/fisiologiaRESUMO
PURPOSE: DNA repair defects have been previously reported in myeloproliferative neoplasms (MPN). Inhibitors of PARP have shown activity in solid tumors with defects in homologous recombination (HR). This study was performed to assess MPN sensitivity to PARP inhibitors ex vivo EXPERIMENTAL DESIGN: HR pathway integrity in circulating myeloid cells was evaluated by assessing the formation of RAD51 foci after treatment with ionizing radiation or PARP inhibitors. Sensitivity of MPN erythroid and myeloid progenitors to PARP inhibitors was evaluated using colony formation assays. RESULTS: Six of 14 MPN primary samples had reduced formation of RAD51 foci after exposure to ionizing radiation, suggesting impaired HR. This phenotype was not associated with a specific MPN subtype, JAK2 mutation status, or karyotype. MPN samples showed increased sensitivity to the PARP inhibitors veliparib and olaparib compared with normal myeloid progenitors. This hypersensitivity, which was most pronounced in samples deficient in DNA damage-induced RAD51 foci, was observed predominantly in samples from patients with diagnoses of chronic myelogenous leukemia, chronic myelomonocytic leukemia, or unspecified myelodysplastic/MPN overlap syndromes. CONCLUSIONS: Like other neoplasms with HR defects, MPNs exhibit PARP inhibitor hypersensitivity compared with normal marrow. These results suggest that further preclinical and possibly clinical study of PARP inhibitors in MPNs is warranted. Clin Cancer Res; 22(15); 3894-902. ©2016 AACR.
Assuntos
Antineoplásicos/efeitos adversos , Hipersensibilidade a Drogas/etiologia , Transtornos Mieloproliferativos/complicações , Inibidores de Poli(ADP-Ribose) Polimerases/efeitos adversos , Antineoplásicos/uso terapêutico , Proteína BRCA1/genética , Benzimidazóis/efeitos adversos , Benzimidazóis/farmacologia , Dano ao DNA , Metilação de DNA , Reparo do DNA , Tolerância a Medicamentos/genética , Genômica/métodos , Humanos , Janus Quinase 2/genética , Mutação , Transtornos Mieloproliferativos/diagnóstico , Transtornos Mieloproliferativos/tratamento farmacológico , Transtornos Mieloproliferativos/genética , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Rad51 Recombinase/genética , Rad51 Recombinase/metabolismoRESUMO
[reaction: see text] A highly convergent synthesis of the angiogenesis inhibitor luminacin D has been achieved in 13 linear steps (19 steps total, 5.3% overall yield) utilizing a samarium(II) iodide-mediated mixed tandem aldol/Evans-Tishchenko reaction to construct the carbohydrate precursor. The modular synthetic design will allow derivatization at key positions necessary for biochemical mode of action studies.
Assuntos
Inibidores da Angiogênese/síntese química , Benzaldeídos/síntese química , Compostos de Espiro/síntese química , Inibidores da Angiogênese/farmacologia , Animais , Benzaldeídos/farmacologia , Bovinos , Divisão Celular/efeitos dos fármacos , Endotélio Vascular/citologia , Concentração Inibidora 50 , Compostos de Espiro/farmacologia , Relação Estrutura-AtividadeRESUMO
PURPOSE: Previous studies have shown that the replication checkpoint, which involves the kinases ataxia telangiectasia mutated and Rad3 related (ATR) and Chk1, contributes to cytarabine resistance in cell lines. In the present study, we examined whether this checkpoint is activated in clinical acute myelogenous leukemia (AML) during cytarabine infusion in vivo and then assessed the impact of combining cytarabine with the recently described Chk1 inhibitor SCH 900776 in vitro. EXPERIMENTAL DESIGN: AML marrow aspirates harvested before and during cytarabine infusion were examined by immunoblotting. Human AML lines treated with cytarabine in the absence or presence of SCH 900776 were assayed for checkpoint activation by immunoblotting, nucleotide incorporation into DNA, and flow cytometry. Long-term effects in AML lines, clinical AML isolates, and normal myeloid progenitors were assayed using clonogenic assays. RESULTS: Immunoblotting revealed increased Chk1 phosphorylation, a marker of checkpoint activation, in more than half of Chk1-containing AMLs after 48 hours of cytarabine infusion. In human AML lines, SCH 900776 not only disrupted cytarabine-induced Chk1 activation and S-phase arrest but also markedly increased cytarabine-induced apoptosis. Clonogenic assays demonstrated that SCH 900776 enhanced the antiproliferative effects of cytarabine in AML cell lines and clinical AML samples at concentrations that had negligible impact on normal myeloid progenitors. CONCLUSIONS: These results not only provide evidence for cytarabine-induced S-phase checkpoint activation in AML in the clinical setting, but also show that a selective Chk1 inhibitor can overcome the S-phase checkpoint and enhance the cytotoxicity of cytarabine. Accordingly, further investigation of the cytarabine/SCH 900776 combination in AML appears warranted.
Assuntos
Proteínas de Ciclo Celular/metabolismo , Citarabina/administração & dosagem , Leucemia Mieloide Aguda , Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Apoptose/efeitos dos fármacos , Proteínas Mutadas de Ataxia Telangiectasia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proteínas de Ciclo Celular/antagonistas & inibidores , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Quinase 1 do Ponto de Checagem , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Inibidores de Proteínas Quinases/administração & dosagem , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Pirazóis/administração & dosagem , Pirimidinas/administração & dosagemRESUMO
A number of inhibitors of NF-kappaB signaling arising from our recent syntheses of isopanepoxydone and panepoxydone have been identified. Structure-activity data have been correlated to allow the design and synthesis of an affinity reagent for the isolation and identification of any relevant cellular target.
Assuntos
Biotina/análogos & derivados , Compostos Bicíclicos Heterocíclicos com Pontes/química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Indicadores e Reagentes/síntese química , Indicadores e Reagentes/farmacologia , NF-kappa B/antagonistas & inibidores , Biotinilação , Linhagem Celular , Desenho de Fármacos , Eletroforese em Gel de Poliacrilamida , Células HeLa , Humanos , NF-kappa B/fisiologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Relação Estrutura-AtividadeRESUMO
p34, a specific p-nitrophenyl phosphatase (pNPPase) was identified and purified from the murine cell line EL4 in a screen for the intracellular molecular targets of the antiinflammatory natural product parthenolide. A BLAST search analysis revealed that it has a high degree of sequence similarity to two yeast alkaline phosphatases. We have cloned, sequenced, and expressed p34 as a GST-tagged fusion protein in Escherichia coli and an EE-epitope-tagged fusion protein in mammalian cells. Using p-nitrophenyl phosphate (pNPP) as a substrate, p34 is optimally active at pH 7.6 with a K(m) of 1.36 mM and K(cat) of 0.052 min(-1). Addition of 1 mM Mg(2+) to the reaction mixture increases its activity by 14-fold. Other divalent metal ions such as Co(2+) and Mn(2+) also stimulated the activity of the enzyme, while Zn(2+), Fe(2+), and Cu(2+) had no effect. Furthermore, both NaCl and KCl enhanced the activity of the enzyme, having maximal effect at 50 and 75 mM, respectively. The enzyme is inhibited by sodium orthovanadate but not by sodium fluoride or okadaic acid. Mutational analysis data suggest that p34 belongs to the group of phosphatases characterized by the sequence motif DXDX(T/V).