RESUMO
Absence-like seizures in the Genetic Absence Epilepsy Rats from Strasbourg (GAERS) model are believed to arise in hyperexcitable somatosensory cortical neurons, however the cellular basis of this increased excitability remains unknown. We have previously shown that expression of the Transmembrane AMPA receptor Regulatory Protein (TARP), stargazin, is elevated in the somatosensory cortex of GAERS. TARPs are critical regulators of the trafficking and function of AMPA receptors. Here we examine the developmental expression of stargazin and the impact this may have on AMPA receptor trafficking in the GAERS model. We show that elevated stargazin in GAERS is associated with an increase in AMPA receptor proteins, GluA1 and GluA2 in the somatosensory cortex plasma membrane of adult epileptic GAERS. Elevated stargazin expression is not seen in the epileptic WAG/Rij rat, which is a genetically distinct but phenotypically similar rat model also manifesting absence seizures, indicating that the changes seen in GAERS are unlikely to be a secondary consequence of the seizures. In juvenile (6 week old) GAERS, at the age when seizures are just starting to be expressed, there is elevated stargazin mRNA, but not protein expression for stargazin or the AMPA receptor subunits. In neonatal (7 day old) pre-epileptic GAERS there was no alteration in stargazin mRNA expression in any brain region examined. These data demonstrate that stargazin and AMPA receptor membrane targeting is altered in GAERS, potentially contributing to hyperexcitability in somatosensory cortex, with a developmental time course that would suggest a pathophysiological role in the epilepsy phenotype.
Assuntos
Canais de Cálcio/biossíntese , Epilepsia/genética , Neurônios/metabolismo , Receptores de AMPA/biossíntese , Córtex Somatossensorial/metabolismo , Animais , Canais de Cálcio/genética , Membrana Celular/genética , Membrana Celular/patologia , Membrana Celular/fisiologia , Modelos Animais de Doenças , Epilepsia/patologia , Epilepsia/fisiopatologia , Predisposição Genética para Doença , Neurônios/patologia , Neurônios/fisiologia , Fenótipo , Ratos , Ratos Mutantes , Receptores de AMPA/genética , Córtex Somatossensorial/patologia , Córtex Somatossensorial/fisiopatologiaRESUMO
Stargazin is membrane bound protein involved in trafficking, synapse anchoring and biophysical modulation of AMPA receptors. A quantitative trait locus in chromosome 7 containing the stargazin gene has been identified as controlling the frequency and duration of absence seizures in the Genetic Absence Epilepsy Rats from Strasbourg (GAERS). Furthermore, mutations in this gene result in the Stargazer mouse that displays an absence epilepsy phenotype. GAERS stargazin mRNA expression is increased 1.8 fold in the somatosensory cortex and by 1.3 fold in the thalamus. The changes were present before and after the onset of absence seizures indicating that increases are not a secondary consequence of the seizures. Stargazin protein expression was also significantly increased in the somatosensory cortex after the onset of spontaneous seizures. The results are of significant importance beyond the GAERS model, as they are the first to show that an increase in stargazin expression may be pro-epileptic.
Assuntos
Canais de Cálcio/metabolismo , Córtex Cerebral/metabolismo , Epilepsia Tipo Ausência/metabolismo , Tálamo/metabolismo , Regulação para Cima/genética , Animais , Canais de Cálcio/genética , Córtex Cerebral/fisiopatologia , Modelos Animais de Doenças , Epilepsia Tipo Ausência/genética , Epilepsia Tipo Ausência/fisiopatologia , Predisposição Genética para Doença/genética , Mutação/genética , Vias Neurais/metabolismo , Vias Neurais/fisiopatologia , RNA Mensageiro/metabolismo , Ratos , Ratos Mutantes , Córtex Somatossensorial/metabolismo , Córtex Somatossensorial/fisiopatologia , Tálamo/fisiopatologiaRESUMO
ADAM22 is one of three catalytically inactive ADAM family members highly expressed in the brain. Preliminary functional studies suggest possible roles in epilepsy and myelination. We report an additional eight new splice variants of human ADAM22. Analysis of the altered splicing patterns of ADAM22 mRNAs in glioma allows us to suggest alternate splicing patterns in normal brain compared to glioma may represent differential use of exon 32. We also report diversity in the 5' leader sequences of ADAM22 mRNAs as a consequence of alternate transcriptional initiation sites. ADAM22 has an additional transcriptional initiation element producing transcripts lacking the exon 1 sequence including the signal peptide. Variable transcriptional initiation in exon 1 produces a range of ADAM22 5' leader sequence lengths, all of which are significantly longer than those described in NCBI reference sequences. Longer 5' leader sequences contain a second upstream AUG codon which acts to inhibit ADAM22 translation.
Assuntos
Proteínas ADAM/genética , Glioma/patologia , Proteínas do Tecido Nervoso/genética , RNA Mensageiro/genética , Proteínas ADAM/química , Proteínas ADAM/metabolismo , Processamento Alternativo , Encéfalo/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Códon , Códon de Terminação , Primers do DNA , Éxons , Etiquetas de Sequências Expressas , Genes Reporter , Glioma/metabolismo , Humanos , Rim/citologia , Luciferases/metabolismo , Estadiamento de Neoplasias , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/metabolismo , Fases de Leitura Aberta , Reação em Cadeia da Polimerase , Isoformas de Proteínas , Sinais Direcionadores de Proteínas , Estrutura Terciária de Proteína , Sítio de Iniciação de TranscriçãoRESUMO
Using FDC-P1 derived cell lines which ectopically express either the wild type or mutant forms of the murine CSF-1 receptor in which individual tyrosine residues have been replaced with phenylalanine, we analysed the requirement for tyrosine residues of the receptor for the activation of STAT proteins in response to CSF-1. We found Y706 to be required for efficient activation of STAT1. The activation of STAT3 was not affected by the mutation of Y706 to phenylalanine. The addition of phosphopeptides spanning Y708 of the human CSF-1 receptor (identical with the sequence surrounding Y706 of the murine receptor) to electrophoretic mobility shift assays led to competition of the formation of STAT1 containing complexes, SIF-B and SIF-C with the DNA probe. These phosphopeptides did, however, not affect the formation of the STAT3 containing complex, SIF-A, with the probe. Replacement of Y807 with phenylalanine led to a complete block of activation of all STAT proteins in response to CSF-1, however, this phosphotyrosine does not appear to represent a STAT binding site of the receptor as a phosphopeptide spanning Y809 of the human CSF-1 receptor could not compete any STAT/DNA complex formation in electrophoretic mobility shift assays.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Fator Estimulador de Colônias de Macrófagos/farmacologia , Proteínas Tirosina Quinases , Receptor de Fator Estimulador de Colônias de Macrófagos/efeitos dos fármacos , Transativadores/metabolismo , Animais , Sítios de Ligação , Linhagem Celular , Humanos , Camundongos , Fosforilação , Proteínas/metabolismo , Receptor de Fator Estimulador de Colônias de Macrófagos/metabolismo , Fator de Transcrição STAT1 , Fator de Transcrição STAT3 , Transdução de Sinais , TYK2 QuinaseRESUMO
PURPOSE: A phase II study of liposomal doxorubicin was conducted in patients with ovarian cancer who failed to respond to platinum- and paclitaxel-based regimens. Liposomal doxorubicin was selected as a result of its superior activity against ovarian cancer xenografts relative to free doxorubicin and activity in refractory ovarian cancer patients that was noted during the phase I study. PATIENTS AND METHODS: Thirty-five consecutive patients were accrued in two institutions (22 in one and 13 in the other). All had progressive disease after either cisplatin or carboplatin and paclitaxel, or at least one platinum-based and one paclitaxel-based regimen. Patients received intravenous (I.V.) liposomal doxorubicin 50 mg/m2 every 3 weeks with a dose reduction to 40 mg/m2 in the event of grade 3 or 4 toxicities, or a lengthening of the interval to 4 weeks (and occasionally to 5 weeks) with persistence of grade 1 or 2 toxicities beyond 3 weeks. RESULTS: Nine clinical responses (one complete response [CR], eight partial responses [PRs]) were observed in 35 patients (25.7%), with seven of these having been confirmed by two consecutive computed tomographic (CT) measurements. The median progression-free survival was 5.7 months with an overall survival of 1.5 to 24+ months (median, 11 months). Although 13 patients experienced grade 3 or 4 nonhematologic skin and mucosal toxicities (either hand-foot syndrome or stomatitis), with dose modifications, the treatment was very well tolerated. Nausea that was clearly attributable to the drug, hair loss, extravasation necrosis, or decreases in ejection fraction did not occur. CONCLUSION: Liposomal doxorubicin has substantial activity against ovarian cancer refractory to platinum and paclitaxel. The responses achieved with liposomal doxorubicin were durable and maintained with minimal toxicity. This liposomal formulation should be evaluated further in combination with other drugs in less refractory patients.
Assuntos
Antibióticos Antineoplásicos/uso terapêutico , Doxorrubicina/uso terapêutico , Neoplasias Ovarianas/tratamento farmacológico , Idoso , Antibióticos Antineoplásicos/efeitos adversos , Antineoplásicos/uso terapêutico , Antígeno Ca-125/sangue , Cisplatino/uso terapêutico , Intervalo Livre de Doença , Doxorrubicina/efeitos adversos , Esquema de Medicação , Portadores de Fármacos , Resistencia a Medicamentos Antineoplásicos , Feminino , Humanos , Infusões Intravenosas , Lipossomos , Pessoa de Meia-Idade , Neutropenia/induzido quimicamente , Neoplasias Ovarianas/imunologia , Paclitaxel/uso terapêutico , Úlcera/induzido quimicamenteRESUMO
Glycinamide ribonucleotide formyltransferase (GARFT) is a component of the de novo purine synthesis pathway. AG2034 is a specific inhibitor of GARFT that was designed based on the GARFT crystal structure. In conjunction with Phase I studies at four clinical centers in the United States and United Kingdom, AG2034 pharmacology was evaluated in 54 patients receiving 1-11 mg/m2 AG2034 as a 2-5 min injection. Blood samples were obtained just prior to and 5, 15, 30, and 45 min, and 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72, and 96 h after bolus injection during course 1. Limited sampling was also performed on course 3. Plasma AG2034 was measured using a sensitive and reproducible ELISA assay. AG2034 demonstrated a trimodal elimination pattern over 24 h, with median half-life (t(1/2))alpha = 8.7 min, t(1/2)beta = 72.6 min, and t(1/2)gamma = 364.2 min. AG2034 systemic clearance ranged from 9.4-144.5 ml/min/m2, and volume of distribution was 1.2-7.6 liters/m2. Course 1 AG2034 area under the concentration versus time curve (AUC) had a linear relationship with dose (r(s) = 0.86). Accumulation of AG2034 was evident, because course 3 AUC was higher than course 1 in 23 of 23 evaluable patients, but was not associated with an increase in erythrocyte AG2034. AG2034 systemic exposure had an impact on toxicity, because course 1 and course 3 AG2034 AUCs were significantly higher for patients with grade III/IV toxicity than patients with less than grade II toxicity (P < 0.001 and P = 0.001 for course 1 and course 3, respectively). This study demonstrates rapid systemic clearance of AG2034 and suggests pharmacokinetic approaches that may minimize patient toxicity and aid the development of this interesting class of anticancer agents.
Assuntos
Antineoplásicos/efeitos adversos , Antineoplásicos/farmacocinética , Glutamatos/efeitos adversos , Glutamatos/farmacocinética , Neoplasias/tratamento farmacológico , Pirimidinas/efeitos adversos , Pirimidinas/farmacocinética , Adulto , Idoso , Antineoplásicos/administração & dosagem , Inibidores Enzimáticos/efeitos adversos , Inibidores Enzimáticos/farmacocinética , Feminino , Glutamatos/administração & dosagem , Humanos , Hidroximetil e Formil Transferases/antagonistas & inibidores , Infusões Intravenosas , Masculino , Taxa de Depuração Metabólica , Pessoa de Meia-Idade , Fosforribosilglicinamido Formiltransferase , Pirimidinas/administração & dosagem , Análise de Regressão , Reino Unido , Estados UnidosRESUMO
Stout and colleagues [Proc Am Assoc Cancer Res 1993, 34, p. 298] previously reported that both hydrocortisone and tamoxifen increased the free fraction of suramin in human plasma. We examined several corticosteroids as well as tamoxifen for their effects on suramin protein binding and also evaluated hydrocortisone for its ability to modulate suramin activity in PC-3 and MCF-7 cells. Greater than 99% of the suramin was protein bound in undiluted human plasma. However, the free fraction of suramin was increased with the reduced plasma protein levels and increased suramin concentrations. At concentrations ranging from 1 to 30 microM, neither tamoxifen, hydrocortisone, prednisone nor dexamethasone had any effect on the binding of suramin to human plasma, regardless of protein concentrations. Similar results were observed with fetal calf serum. Hydrocortisone also had no effect on suramin activity against PC-3 and MCF-7 cell in vitro. We conclude from these studies that neither corticosteroids nor tamoxifen affect suramin protein binding or its cytotoxic activity.
Assuntos
Antineoplásicos Hormonais/farmacologia , Antineoplásicos/metabolismo , Proteínas Sanguíneas/metabolismo , Glucocorticoides/farmacologia , Suramina/metabolismo , Tamoxifeno/farmacologia , Células Tumorais Cultivadas/efeitos dos fármacos , Anti-Inflamatórios/farmacologia , Relação Dose-Resposta a Droga , Interações Medicamentosas , Feminino , Humanos , Hidrocortisona/farmacologia , MasculinoRESUMO
The promoter of the human urokinase plasminogen activator (uPA) gene contains a sequence identical with the retinoblastoma control element (RCE) of the murine c-fos gene, as well as several Sp1 binding sites. In a number of cell lines, the uPA promoter is activated during enforced expression of the retinoblastoma protein, pRB. Electrophoretic mobility-shift assays revealed that the RCE sequence of the uPA gene forms only one specific DNA-protein complex that does not contain pRB. The formation of the RCE-protein complex can be inhibited by 20 molar excess of the unlabeled RCE sequences and by 5 molar excess of the unlabeled E2F binding site. The RCE of the human uPA gene interacts specifically with a protein, which appears to be distinct from members of the E2F family of proteins, Sp1, ATF2, and Elf-1, which are all transcription factors shown to be regulated by pRB.
Assuntos
Regulação Enzimológica da Expressão Gênica , Regiões Promotoras Genéticas , Proteína do Retinoblastoma/metabolismo , Fatores de Transcrição/metabolismo , Ativador de Plasminogênio Tipo Uroquinase/biossíntese , Ativador de Plasminogênio Tipo Uroquinase/genética , Animais , Sequência de Bases , Sítios de Ligação , Neoplasias da Mama , Linhagem Celular , Cloranfenicol O-Acetiltransferase/biossíntese , Sequência Consenso , Genes fos , Células HeLa , Humanos , Pulmão , Camundongos , Leite , Dados de Sequência Molecular , Oligodesoxirribonucleotídeos , Plasmídeos , Proteínas Recombinantes/biossíntese , Mapeamento por Restrição , TransfecçãoRESUMO
A new benzodiazepine, chlordesmethyldiazepam, was administered at a dose of 6 mg/day to 27 patients (18 neurotics and 9 psychotics) with the common symptom of anxiety. The study period was limited to eight days for the whole group, although the drug has been given to some patients for 38 days. Changes in global scores in neurotic patients were determined by administering the Wittenborn and Hamilton rating scales. In psychotic patients the same rating scales were used in addition to the BPRS. A multistimulator was used to evaluate the performance recording complex reaction times (CRT). The statistical evaluation of results shows a highly significant amelioration of all the studied parameters except for reaction times in the psychotic group.
Assuntos
Ansiolíticos/uso terapêutico , Ansiedade/tratamento farmacológico , Benzodiazepinas , Diazepam/análogos & derivados , Hipnóticos e Sedativos , Transtornos Neuróticos/complicações , Nordazepam/análogos & derivados , Transtornos Psicóticos/complicações , Adolescente , Adulto , Idoso , Ansiedade/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nordazepam/uso terapêutico , Escalas de Graduação Psiquiátrica , Tempo de Reação/efeitos dos fármacosRESUMO
PURPOSE: To identify a recommended phase II dose for the second generation glycinamide ribonucleotide transformylase (GARFT) inhibitor, AG2034, administered by intravenous bolus every 3 weeks without folate supplementation and to describe AG2034 pharmacokinetics. METHODS: Adults with advanced malignancies were enrolled in cohorts of three per dose level with expansion to six upon observation of dose-limiting toxicity (DLT). The maximum tolerated dose (MTD) was defined as the dose at which two of up to six patients experienced DLT. Upon identification of an MTD and evidence of cumulative toxicity, a lower intermediate dose was explored as a candidate phase II dose. AG2034 plasma concentrations were measured using an ELISA assay. RESULTS AND CONCLUSIONS: The recommended phase II dose is 5.0 mg/m2. DLTs were anemia, thrombocytopenia, mucositis, diarrhea, hyperbilirubinemia, fatigue, and insomnia. Toxicities were modestly cumulative over three courses. Pharmacokinetic analysis showed a dose-AUC0-24 relationship and a progressive increase in AG2034 AUC0-24 over three courses. Both pharmacokinetic and pharmacodynamic factors may contribute to the modest cumulative toxicity observed with AG2034.
Assuntos
Antineoplásicos/uso terapêutico , Inibidores Enzimáticos/uso terapêutico , Glutamatos/uso terapêutico , Hidroximetil e Formil Transferases/antagonistas & inibidores , Neoplasias/tratamento farmacológico , Pirimidinas/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Esquema de Medicação , Feminino , Glutamatos/efeitos adversos , Glutamatos/farmacocinética , Humanos , Masculino , Pessoa de Meia-Idade , Fosforribosilglicinamido Formiltransferase , Pirimidinas/efeitos adversos , Pirimidinas/farmacocinéticaAssuntos
Proteínas de Ligação a DNA/análise , Células 3T3 , Animais , Sequência de Bases , Proteínas de Ligação a DNA/metabolismo , Eletroforese , Immunoblotting , Camundongos , Dados de Sequência Molecular , Fator de Transcrição STAT1 , Fator de Transcrição Sp1/metabolismo , Transativadores/metabolismoRESUMO
Colony-stimulating factor (CSF-1) activates several members belonging to the STAT (signal transducers and activators of transcription) family of transcription factors. We investigated the DNA binding complexes activated by CSF-1 in several cell lines and compared them with complexes activated by platelet-derived growth factor and interleukin 3. Our results indicate that the SIF-A complex activated by CSF-1 and platelet-derived growth factor may contain STAT3/STAT5 heterodimers binding to the high affinity SIF binding site, m67. In addition, both growth factors activate one or several STAT5-containing protein complexes binding to the prolactin-inducible element, PIE. The formation of these complexes was cell type and growth factor specific. Interleukin 3 activated only PIE binding complexes containing STAT5A and STAT5B and did not activate m67 binding complexes. It appears, therefore, that STAT5 cannot bind to m67 as a homodimer, but it can bind if it is dimerized with STAT3, whereas it can bind to the PIE element without being either complexed with STAT3 or any other known STAT protein, possibly as a homodimer or as STAT5A/STAT5B heterodimer. However, in addition, STAT5 may heterodimerize with other proteins and form novel PIE binding complexes.
Assuntos
Proteínas de Ligação a DNA/biossíntese , Fator Estimulador de Colônias de Macrófagos/farmacologia , Proteínas do Leite , Fator de Crescimento Derivado de Plaquetas/farmacologia , Transativadores/biossíntese , Sequência de Aminoácidos , Animais , Sequência de Bases , Sítios de Ligação , Linhagem Celular , DNA/genética , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Humanos , Interleucina-3/farmacologia , Camundongos , Dados de Sequência Molecular , Estrutura Molecular , Prolactina/metabolismo , Conformação Proteica , Fator de Transcrição STAT3 , Fator de Transcrição STAT5 , Transativadores/química , Transativadores/genética , Proteínas Supressoras de TumorRESUMO
There is evidence that the cellular responses to cytokines, such as granulocyte colony stimulating factor (G-CSF) and interferons, depend on prior activation of components of the JAK/STAT signalling pathway. We report here that the myeloid cell line NFS-60 shows aberrant JAK/STAT signalling yet elicits expected biological responses to G-CSF and interferons-alpha/beta and gamma. Instead of increased phosphorylation of JAK1 and JAK2 in response to G-CSF and interferon-gamma, and JAK1 and Tyk2 in response to interferon-alpha/beta, we observed only an increase of phosphorylation of Tyk2 in response to all of these cytokines in NFS-60 cells. The subset of STAT proteins being activated in response to these cytokines was unusual as well. G-CSF activated STAT3 and STAT5A, whereas interferons activated, in addition to STAT1 and STAT5 other, as yet unidentified, DNA binding proteins. However, NFS-60 cells show normal biological responses to these cytokines, such as proliferation in response to G-CSF, and reduction of proliferation, induction of an anti-viral response and induction of specific genes in response to interferons.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Fator Estimulador de Colônias de Granulócitos/farmacologia , Interferon-alfa/farmacologia , Interferon beta/farmacologia , Interferon gama/farmacologia , Proteínas Tirosina Quinases/metabolismo , Transdução de Sinais , Transativadores/metabolismo , Animais , Antivirais/metabolismo , Divisão Celular/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Janus Quinase 3 , Camundongos , Proteínas/metabolismo , Fator de Transcrição STAT1 , TYK2 Quinase , Células Tumorais CultivadasRESUMO
We present evidence that the transcription factor STAT3, derived from uninduced cells, can form stable homodimers, which are independent of the tyrosine phosphorylation status of the protein. The strong interaction, which is resistant to many denaturing agents, is dependent on the presence of divalent cations. The presence of the homodimer was initially observed in immunoprecipitates of STAT3 and was detected upon fractionation of cell lysates. These dimers are different in structure from dimers observed after cytokine stimulation of cells, which results in tyrosine phosphorylation of STAT3 and dimerization involving the SH2 domain of STAT3.
Assuntos
Cátions Bivalentes/farmacologia , Proteínas de Ligação a DNA/química , Transativadores/química , Células Cultivadas , Quelantes/farmacologia , Sondas de DNA/metabolismo , Proteínas de Ligação a DNA/análise , Dimerização , Ácido Edético/farmacologia , Interferon gama/farmacologia , Fator Estimulador de Colônias de Macrófagos/farmacologia , Fosforilação , Fosfotirosina/análise , Conformação Proteica , Fator de Transcrição STAT3RESUMO
M1/WT4 cells, derived from the murine myeloid leukemic M1 cells by over-expression of the receptor for CSF-1, were transfected with expression vectors encoding SOCS-1, SOCS-2, SOCS-3 or Cis-1. The differentiation response to CSF-1 and IL-6 was analyzed in the resulting cell lines. Myeloid differentiation in response to CSF-1 was not affected by any of the SOCS proteins, whereas the IL-6-mediated differentiation was inhibited by SOCS-1 and SOCS-3 and slightly delayed by SOCS-2 expression. In M1/WT4 cells IL-6 causes strong tyrosine phosphorylation of STAT3, whereas the response to CSF-1 is weaker. The expression of the SOCS proteins had no effect on CSF-1 mediated STAT3 tyrosine phosphorylation; however, SOCS-1 and SOCS-3 reduced the tyrosine phosphorylation of STAT3 in response to IL-6 but did not abolish it. It appears, therefore, that SOCS-1, -2 and -3 and Cis-1 do not inhibit tyrosine kinase activity involved in CSF-1 mediated cell differentiation, whereas SOCS-1 and -3 are inhibiting kinase activity required for IL-6-mediated differentiation.
Assuntos
Interleucina-6/farmacologia , Fator Estimulador de Colônias de Macrófagos/farmacologia , Macrófagos/citologia , Proteínas/farmacologia , Proteínas Repressoras , Proteínas de Fase Aguda/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Camundongos , Fator de Transcrição STAT3 , Transdução de Sinais/efeitos dos fármacos , Proteína 3 Supressora da Sinalização de Citocinas , Proteínas Supressoras da Sinalização de Citocina , Transativadores/metabolismo , Fatores de Transcrição/metabolismo , Células Tumorais Cultivadas , Domínios de Homologia de src/efeitos dos fármacosRESUMO
A randomized, double-blind, placebo-controlled trial was conducted in eight hematologic units to determine the efficacy and safety of oral enoxacin for infection prevention in adult patients with acute nonlymphocytic leukemia. One hundred nineteen patients undergoing remission induction or consolidation chemotherapy were enrolled; 62 of them received enoxacin (400 mg orally every 12 h). Patients received antifungal prophylaxis with oral mycostatin (1,000,000 U four times daily) or clotrimazole (1 troche five times daily). Analysis was performed on an intent-to-treat basis. There was no significant difference between groups in race, age, or type and stage of leukemia, but there were more males in the placebo group (P = 0.073 [Fisher's exact test]). Fewer enoxacin patients had gram-negative bacteremia (1 versus 14 [P < 0.001]), gram-negative infection at any site (2 versus 19 [P < 0.001]), or bacterial and/or fungal infection (17 versus 26 [P = 0.056]). There was no significant difference in the number of patients with gram-positive infection at any site (12 versus 16), gram-positive bacteremia (9 versus 10), deep fungal infection (6 versus 2), death (2 versus 3), other antimicrobial therapy required (48 versus 48), therapy with amphotericin B (15 versus 7 [P = 0.105]), any adverse event (45 versus 36), or any study drug-associated adverse events (13 versus 6). Logistic regression confirmed (odds ratios and 95% confidence intervals are given in parentheses) that enoxacin reduced the risk of gram-negative infection (0.07; 0.01 to 0.30), especially gram-negative bacillary bacteremia (0.05; 0.01 to 0.37), without altering the risk of gram-positive bacterial (0.63; 0.26 to 1.5), deep fungal (2.57; 0.47 to 13.9), or Clostridium difficile (1.16; 0.3 to 4.56) infection. The median time to the onset of fever of more than or equal 102.8 F (39.3 degree C) was 32 days for the enoxacin group versus 15 days for patients receiving placebo (P=0.0007 [Wilcoxon test]). In patients with acute nonlymphocytic leukemia, oral enoxacin prevents gram-negative infections, delays the onset of fever, does not alter the incidence of gram-positive or proven deep fungal infections, and is well tolerated.
Assuntos
Infecções Bacterianas/prevenção & controle , Enoxacino/uso terapêutico , Leucemia Mieloide Aguda/complicações , Micoses/prevenção & controle , Administração Oral , Adulto , Idoso , Infecções Bacterianas/etiologia , Infecções Bacterianas/microbiologia , Método Duplo-Cego , Enoxacino/administração & dosagem , Enoxacino/efeitos adversos , Feminino , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/microbiologia , Masculino , Pessoa de Meia-Idade , Micoses/etiologia , Micoses/microbiologiaRESUMO
FDC-P1 cells expressing the wildtype CSF-1 receptor, FDwtfms, differentiate into macrophages during incubation with CSF-1. This response is amplified in the presence of interferon-gamma. Cells expressing the 807F mutant receptor, 807F cells, proliferate in response to CSF-1 and do not differentiate. However, in response to CSF-1 and interferon-gamma they differentiate as well. CSF-1 causes the activation of STAT proteins in FDwtfms cells, but not in 807F cells. Cellular differentiation correlates with a sustained activation of STAT1 and STAT3 in response to interferon-gamma over at least 40 hours. However, interferon-gamma alone did not cause differentiation of cells expressing either receptor. Other defects in response to CSF-1 of the 807F cells, such as lack of PLC gamma 2 activation, were not complemented by co-incubation of the cells with CSF-1 and interferon-gamma. It appears that a combination of signaling pathways are activated by CSF-1 and interferon-gamma which caused the shift of response from proliferation to differentiation in the 807F cells and an enhanced differentiation in the FDwtfms cells.
Assuntos
Células-Tronco Hematopoéticas/citologia , Interferon gama/farmacologia , Fator Estimulador de Colônias de Macrófagos/farmacologia , Macrófagos/citologia , Animais , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Proteínas de Ligação a DNA/metabolismo , Sinergismo Farmacológico , Ativação Enzimática , Células-Tronco Hematopoéticas/efeitos dos fármacos , Isoenzimas/metabolismo , Macrófagos/efeitos dos fármacos , Camundongos , Mutagênese Sítio-Dirigida , Fosfolipase C gama , Fosforilação , Receptor de Fator Estimulador de Colônias de Macrófagos/genética , Receptor de Fator Estimulador de Colônias de Macrófagos/metabolismo , Fator de Transcrição STAT1 , Fator de Transcrição STAT3 , Transdução de Sinais , Transativadores/metabolismo , Fosfolipases Tipo C/metabolismo , Tirosina/metabolismoRESUMO
The novel folate analogue AG2034, which was designed as an inhibitor of GARFT (glycinamide ribonucleotide formyltransferase), was evaluated in this phase I study under the auspices of The Cancer Research Campaign, UK. AG2034 blocks de novo purine synthesis through inhibition of GARFT. A total of 28 patients with histologically proven intractable cancers were enrolled. AG2034 was administered as a short intravenous infusion once every 3 weeks. 8 dose levels ranging from 1-11 mg/m(2)were evaluated with patients receiving up to 6 cycles. Dose-limiting toxicities in the form of mucositis, diarrhoea and vomiting were observed at doses of 6 mg/m(2)and above. Significant levels of thrombocytopenia, neutropenia and anaemia were also recorded. Other sporadic toxicities included fatigue and myalgia. The MTD with this schedule of AG2034 was 5 mg/m(2). Most side effects occurred more frequently with cumulative dosing. In keeping with this, pharmacokinetic analysis revealed evidence of drug accumulation. The AG2034 AUC(0-24)increased by a median of 184% (range 20-389%) from cycle 1 to 3 in all 10 patients examined. No objective antitumour responses were observed in the study.
Assuntos
Antineoplásicos/farmacocinética , Glutamatos/farmacocinética , Neoplasias/tratamento farmacológico , Pirimidinas/farmacocinética , Adulto , Idoso , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Área Sob a Curva , Diarreia/induzido quimicamente , Relação Dose-Resposta a Droga , Feminino , Glutamatos/administração & dosagem , Glutamatos/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Mucosa Bucal/efeitos dos fármacos , Mucosa Bucal/patologia , Náusea/induzido quimicamente , Neoplasias/metabolismo , Neutropenia/induzido quimicamente , Pirimidinas/administração & dosagem , Pirimidinas/efeitos adversos , Estomatite/induzido quimicamente , Trombocitopenia/induzido quimicamente , Resultado do TratamentoRESUMO
Colony-stimulating factor 1 (CSF-1) causes the activation of STAT1 and STAT3 transcription factors in bone marrow macrophages (BMM), in the macrophage cell line BAC1.2F5, and in fibroblasts that express the wild-type receptor for CSF-1. Fibroblasts expressing a mutant receptor in which the tyrosine 809 is replaced with phenylalanine do not activate STAT proteins in response to CSF-1. The activation of the STAT proteins in BMM is accompanied by tyrosine phosphorylation of Tyk2. In fibroblasts, the activation of the STAT proteins is accompanied by tyrosine phosphorylation of Tyk2 and JAK1. We propose that these JAK kinases are subjected to very rapid phosphorylation in response to CSF-1, followed by rapid dephosphorylation. Furthermore, we propose that kinases other than JAK kinase may be involved in the phosphorylation of the STAT proteins in response to CSF-1.