RESUMO
Signal transducer and activator of transcription 6 (STAT6) is essential for the biological activities of interleukin-4 (IL-4) and the development of allergic responses in mice. Here we report on a sensitive and specific assay for STAT6 activation in response to IL-4. We took advantage of double-stranded oligonucleotide probes containing a STAT6-binding gene-sequence from the promotor of the immunoglobulin heavy chain germline epsilon transcript to study the IL-4-induced DNA binding of STAT6. Using these probes, we show that repeated adjacent STAT6-binding sites result in enhanced STAT6-DNA binding. Moreover, the distance between the binding sites is critical for STAT-DNA binding, i.e. STAT6 binding is decreased at distances above 20 nucleotides between neighbouring binding sites. Using this assay to study cross-talk between IL-4 and chemokines, we provide evidence that MIP-1beta and MIG inhibit IL-4-induced STAT6 activation, whereas other chemokines and cytokines do not. In conclusion, our data show that oligonucleotide fishing is a supplementary tool for studying cytokine cross-talk at a genomic level.
Assuntos
Quimiocinas/metabolismo , Interleucina-4/metabolismo , Transativadores/genética , Transativadores/metabolismo , Animais , Sequência de Bases , Sítios de Ligação/genética , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linhagem Celular , Citocinas/metabolismo , DNA/genética , DNA/metabolismo , Humanos , Interleucina-4/farmacologia , Camundongos , Dados de Sequência Molecular , Sondas de Oligonucleotídeos , Fosforilação , Fator de Transcrição STAT6 , Transativadores/química , Tirosina/metabolismoRESUMO
The cisplatin derivative TNO-6 was evaluated for clinical toxicity in a phase I trial. TNO-6 was given daily for 5 days every 3 weeks as a 30-min IV infusion without hydration. In all, 39 patients with advanced cancer were treated at doses of 2.5-9.0 mg/m2. No dose-limiting nephrotoxicity occurred, but evidence of mild, reversible tubular damage was found. Dose-limiting toxicity was hematologic with both thrombopenia and leukocytopenia, which with high dose levels reached WHO grade 4. Hematologic toxicity was most pronounced for pretreated patients. No antitumor activity was seen. The recommended dose for phase II trials will be 9.0 mg/m2 for previously untreated and 8.0 mg/m2 for pretreated patients.
Assuntos
Neoplasias/tratamento farmacológico , Compostos Organoplatínicos/efeitos adversos , Adulto , Idoso , Avaliação de Medicamentos , Feminino , Humanos , Ácido Iodoipúrico , Túbulos Renais/diagnóstico por imagem , Túbulos Renais/efeitos dos fármacos , Túbulos Renais/patologia , Leucopenia/induzido quimicamente , Masculino , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Compostos Organoplatínicos/administração & dosagem , Ácido Pentético , Proteinúria/induzido quimicamente , Cintilografia , Tecnécio , Pentetato de Tecnécio Tc 99m , Trombocitopenia/induzido quimicamenteRESUMO
To evaluate the value of beta-2-microglobulin as an indicator of acute and long-term cis-platinum-induced nephrotoxicity, 51Cr-EDTA clearance and serum concentration and urinary excretion of beta-2-microglobulin were measured in 18 patients treated with a regimen including cis-platinum. Before treatment all values were within the normal range. During treatment 51Cr-EDTA clearance decreased from 108 to 90 ml/min/1.73 m2 (P less than 0.02). The decrease was irreversible, while a transient 2 to 5-fold increase in beta-2-microglobulin excretion in the urine was seen during treatment. Serum beta-2-microglobulin remained unchanged. The decrease in 51Cr-EDTA clearance was not correlated to either the peak increase in the beta-2-microglobulin excretion or to the time of occurrence of the peak (R = 0.3). Thus, it is not possible to predict the long-term nephrotoxicity of cis-platinum by measuring the beta-2-microglobulin excretion during treatment.