Asunto(s)
Receptores de Estrógenos/química , Receptores de Estrógenos/fisiología , Receptor alfa de Estrógeno , Receptor beta de Estrógeno , Histona Acetiltransferasas , Coactivador 1 de Receptor Nuclear , Isoformas de Proteínas , Receptores de Estrógenos/metabolismo , Factores de Transcripción/metabolismoRESUMEN
1. In glioma C6 cells, the stimulation of P2Y receptors by ADP, ATP and UTP initiated an increase in the intracellular Ca2+ concentration, in a process that involved the release of Ca2+ from InsP(3)-sensitive store and the capacitative, extracellular Ca2+ entry. The presence of external Ca2+ was not necessary to elevate Ca(2+). 2. The rank order of potencies of nucleotide analogues in stimulating [Ca2+](i) was: 2MeSADP > ADP > 2MeSATP = 2ClATP > ATP > UTP. alpha,beta-Methylene ATP, adenosine and AMP were ineffective. 3. ADP and UTP effects were additive, while actions of ATP and UTP were not additive on [Ca2+](i) increase. Similarly, cross-desensitization between ATP and UTP but not between ADP and UTP occurred. 4. Suramin, a non-specific nucleotide receptors inhibitor, antagonized ATP-, UTP- and ADP-evoked Ca2+ responses. PPADS, a selective antagonist of the P2Y(1) receptor-generated InsP(3) accumulation, decreased ADP-initiated Ca2+ response with no effect on ATP and UTP. 5. Pertussis toxin (PTX) reduced ADP- and ATP-induced Ca2+ increases. Short-term treatment with TPA, inhibited both ATP and ADP stimulatory effects on [Ca2+](i). 6. ADP inhibited isoproterenol-induced cyclic AMP accumulation. PTX blocked this effect, but PPADS did not. 7. RT - PCR analysis revealed the molecular identity of P2Y receptors expressed by glioma C6 cells to be both P2Y(1) and P2Y(2). 8. It is concluded that both P2Y(1) and P2Y(2) receptors co-exist in glioma C6 cells. ADP acts as agonist of the first, and ATP and UTP of the second one. Both receptors are linked to phospholipase C (PLC).
Asunto(s)
Neoplasias Encefálicas/fisiopatología , Señalización del Calcio/fisiología , Proteínas de Unión al GTP/fisiología , Glioma/fisiopatología , Fosfato de Piridoxal/análogos & derivados , Receptores Purinérgicos P2/fisiología , Adenosina Difosfato/farmacología , Adenosina Trifosfato/farmacología , Animales , Calcio/metabolismo , Clonación Molecular , AMP Cíclico/metabolismo , Fosfato de Piridoxal/farmacología , Ratas , Receptores Purinérgicos P2Y1 , Receptores Purinérgicos P2Y2 , Células Tumorales Cultivadas , Fosfolipasas de Tipo C/metabolismo , Uridina Trifosfato/farmacologíaRESUMEN
The KDR/flk-1 gene promoter is considered to be endothelial cell-specific. We show its activity in two cancer cell lines of non-endothelial origin: in murine L1 sarcoma and OVP-10 human ovarian carcinoma cell lines. KDR promoter-driven cytosine deaminase gene can be efficiently expressed in these cells leading to sensitization to 5-fluorocytosine, as demonstrated both in vitro and in vivo. Our results indicated that KDR promoter activity is not endothelial cell-exclusive and that this promoter can also be used to obtain specific expression of therapeutic genes in certain cancer cells.
Asunto(s)
Terapia Genética/métodos , Nucleósido Desaminasas/genética , Neoplasias Ováricas/genética , Sarcoma Experimental/genética , Células 3T3 , Animales , Bovinos , División Celular/efectos de los fármacos , División Celular/genética , Citosina Desaminasa , Endotelio Vascular/enzimología , Endotelio Vascular/fisiología , Femenino , Flucitosina/farmacocinética , Flucitosina/farmacología , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones , Ratones Endogámicos BALB C , Nucleósido Desaminasas/metabolismo , Neoplasias Ováricas/enzimología , Regiones Promotoras Genéticas , Sarcoma Experimental/enzimología , Transfección , Células Tumorales CultivadasRESUMEN
We have cloned and sequenced a cDNA of the human homologue of the Saccharomyces cerevisiae Suv3 putative RNA helicase which is indispensable for mitochondrial function in yeast. The human Suv-3-like protein has a typical mitochondrial leader sequence. Northern blot data and analysis of ESTs in the data banks indicate that this human gene (SUPV3L1) is expressed in practically all tissues, though at different levels. Sequence homology analysis has shown a strong conservation of the protein in a number of eukaryotic organisms -- plants, mammals and fungi, but no close homologues exist in bacteria with the exception of the purple bacterium Rhodobacter sphaeroides. This gene is thus ubiquitously present in all eukaryotic organisms.