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1.
A Paraf E Faivre V Zilberfarb A Zachowski L Lelièvre 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1975,281(9):567-570
Using ouabain as a selective agent, we obtained from a contact inhibited and a non contact inhibited cell layer derived from the same plasmocytoma, different resistant cell lines. All of them were ouabain resistant but were also able to grow in presence of normallly toxic levels of cAMP, theophylline and concanavalin A. 相似文献
2.
M C Debons-Guillemin M Canivet M Salle R Emano?l-Ravicovitch J Periès 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1978,286(21):1547-1549
The PCC6 cell line, derived from an A/Heston Mouse Teratocarcinoma, and composed of nullipotential embryonic carcinoma cells (ECC), is completely resistant to infection with type C murine ecotropic viruses. It reacts as other cell lines previously studied which are derived from a 129 Mouse teratocarcinoma and composed of multipotential ECC. 相似文献
3.
F Garcin J Ciesielski-Treska G Ulrich J C Louis P Mandel 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1978,287(11):1023-1026
A stereospecific saturable high affinity binding of 3H-naloxone has been found in 3 glial and 2 neuronal cell lines. Kinetic study of binding seems to indicate only one class of receptor sites in the 5 cell lines. Acute exposure to morphine (1 X 10(-5)M) concurrent with PGE1-induced stimulation of adenylate cyclase did not result in a decrease of the cAMP level in any cell line tested. 相似文献
4.
Unidirectional 22Na fluxes were investigated in human peripheral mononuclear leucocytes. Ouabain inhibited about 60% of Na efflux and the addition of bumetanide further reduced Na efflux rate by about 45%, suggesting the presence of a transport pathway capable of extruding Na against its gradient. Prostaglandins E1 and E2 and exogenous cAMP were found to be potent inhibitors of the bumetanide-sensitive Na efflux without affecting the ouabain-sensitive or the ouabain and bumetanide resistant Na effluxes. 相似文献
5.
Jean-Pierre Vilardaga Guillermo Romero Peter A. Friedman Thomas J. Gardella 《Cellular and molecular life sciences : CMLS》2011,68(1):1-13
The parathyroid hormone (PTH) receptor type 1 (PTHR), a G protein-coupled receptor (GPCR), transmits signals to two hormone
systems—PTH, endocrine and homeostatic, and PTH-related peptide (PTHrP), paracrine—to regulate different biological processes.
PTHR responds to these hormonal stimuli by activating heterotrimeric G proteins, such as GS that stimulates cAMP production. It was thought that the PTHR, as for all other GPCRs, is only active and signals through
G proteins on the cell membrane, and internalizes into a cell to be desensitized and eventually degraded or recycled. Recent
studies with cultured cell and animal models reveal a new pathway that involves sustained cAMP signaling from intracellular
domains. Not only do these studies challenge the paradigm that cAMP production triggered by activated GPCRs originates exclusively
at the cell membrane but they also advance a comprehensive model to account for the functional differences between PTH and
PTHrP acting through the same receptor. 相似文献
6.
Radioresistance in cells with high content of metallothionein 总被引:6,自引:0,他引:6
A. Bakka A. S. Johnsen L. Endresen H. E. Rugstad 《Cellular and molecular life sciences : CMLS》1982,38(3):381-383
Summary An endogenous cytoplasmic protein, metallothionein (MT) apparently gave rise to radioresistance in 2 different cell lines. A dose reduction factor of 1.9 was achieved in MT-containing cells. MT accounted for a 3–4-fold increase of total sulfhydryl groups in the resistant cell strains, compared to the non-resistant lines from which they were derived. The protein is rich in cysteine (30%), an amino acid known to give radioprotection when administered exogeneously. Glutathione levels and cell-cycle phase distribution showed no marked difference between resistant and corresponding non-resistant cells.We thank Dr F. Devik, Dr L. Eldjarn and Dr E. Jellum for stimulating discussions, and Miss A. K. Syversen and Mrs T. Nysted for skillful technical assistance. This work was partly supported by the Norgwegian Council for Science and the Humanitites. LE is a fellow of the Norwegian Society for Fighting Cancer. 相似文献
7.
H. Vapaatalo Inge-Britt Lindén T. Metsä-Ketelä M. Kangasaho K. Laustiola 《Cellular and molecular life sciences : CMLS》1978,34(3):384-385
Summary Carbenoxolone inhibited in vitro cAMP and cGMP phosphodiesterases in a concentration-dependent and noncompetitive manner. Prostaglandin synthetase activity of rabbit kidney medulla was slightly stimulated by carbenoxolone 0.1–0.5 mM, but inhibited by higher concentrations.Acknowledgment. Supported by a grant from the Orion and Medica Scientific Foundation, Finland. 相似文献
8.
C Boissard C Jarrousse G Rosselin 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1977,285(5):567-570
Radioimmunoassay of cyclic AMP (cAMP) in the islets of Langerhans from 48-64 h old Rats was performed after succinylation of the samples. cAMP was detected at 0.03 nM. The cAMP content of islets increases when L-arginine, L-lysine and L alanine are added together in the incubation medium at a concentration of 5-10 mM each. When phosphodiesterase is inhibited by theophylline the three amino acids considerably increase the cAMP content of islets. Thus an increase in cAMP content of the islets was observed with a concentration of amino acids which is efficient in stimulating the insulin and glucagon secretion. 相似文献
9.
Pani A Batetta B Putzolu M Sanna F Spano O Piras S Mulas MF Bonatesta RR Amat di S Filippo C Vargiu L Marceddu T Sanna L La Colla P Dessì S 《Cellular and molecular life sciences : CMLS》2000,57(7):1094-1102
The product of the MDR1 gene (P-gp) has been implicated in the transport of cholesterol from plasma membrane to endoplasmic reticulum for esterification.
In previous studies on leukemia cell lines, we suggested that cholesterol esterification may regulate the rate of cell growth
and that the MDR1 gene might be involved in this process by modulating intracellular cholesterol esters levels. To further investigate this
matter, the rate of cell growth, cholesterol metabolism, expression of the MDR1 gene, and P-gp activity were compared in KB cell lines displaying differences in expression and function of P-gp (drug-sensitive
phenotype versus MDR phenotype). The rate of cell growth correlated with cholesterol esterification in all KB cell lines,
whereas the over-expression of MDR1 observed in the MDR cell lines was not always associated with an increased capacity of cells to esterify cholesterol. Two
known inhibitors of P-gp activity, progesterone and verapamil, strongly inhibited both cholesterol esterification and cell
proliferation in all KB cell lines, but they affected intracellular accumulation of labeled vinblastine only in MDR cell lines.
These results further support a role for cholesterol esters in the regulation of cell growth and suggest that the P-gp expressed
in MDR KB cells is not involved in the general process leading to cholesterol esterification.
Received 14 February 2000; received after revision 10 April 2000; accepted 8 May 2000 相似文献
10.
Some effects of cAMP on replication of Semliki Forest Virus in chick embryo fibroblast cell cultures are described. Depending on concentration, the incorporation of [3H]-uridine into viral RNA or the formation of plaque-forming units is inhibited; the highest concentration tested was 8 mM. Cyclic AMP has an effect of its own and increases the Interferon action in the lower concentration ranges of Interferon (up to 1 unit/ml). The effect of cyclic AMP is fast, needs no induction and is also visible in late phases of viral replication. However, these experiments do not establish a causal relation between cAMP and Interferon. 相似文献
11.
Carbenoxolone inhibited in vitro cAMP and cGMP phosphodiesterases in a concentration-dependent and noncompetitive manner. Prostaglandin synthetase activity of rabbit kidney medulla was slightly stimulated by carbenoxolone 0.1--0.5 mM, but inhibited by higher concentrations. 相似文献
12.
K. von Schwarzenberg S. A. E. Held A. Schaub K. M. Brauer A. Bringmann P. Brossart 《Cellular and molecular life sciences : CMLS》2009,66(7):1295-1308
In order to analyze the effects of peroxisome proliferator-activated receptor-γ (PPARγ) activation on renal cell carcinomas
we utilized several cell lines that were treated with the high affinity PPARγ agonist, troglitazone. Incubation of RCC cells
with troglitazone resulted in reduced secretion of growth factors that was due to the inhibition of MAP kinase signaling and
reduced nuclear localized expression of relB and HIF1alpha. Interestingly, the cell lines used showed a different sensitivity
towards apoptosis induction that did not correlate with the inhibition of growth factors or expression of pro- and antiapoptotic
molecules. To overcome this resistance the cells were treated with a combination of troglitazone and the proteasome inhibitor,
bortezomib. The combination of both compounds induced apoptosis even in cells resistant to both agents alone, due to increased
induction of ER-stress and caspase-3 mediated cell death.
Received 03 September 2009; received after revision 02 February 2009; accepted 10 February 2009 相似文献
13.
C. D. Reymond P. Schaap M. Véron J. G. Williams 《Cellular and molecular life sciences : CMLS》1995,51(12):1166-1174
cAMP plays an essential role duringDictyostelium development both outside and inside the cell. Membrane-bound receptors and adenylyl cyclase are responsible for sensing and producing extracellular cAMP, whereas a phosphodiesterase is responsible for maintaining a low basal level. The molecular events underlying this type of hormone like signalling, which are now beginning to be deciphered, will be presented, in the light of cAMP analogue studies. The importance of intracellular cAMP for cell differentiation has been demonstrated by the central role of the cAMP dependent protein kinase. Mutants as well as strains obtained by reverse genetics will be reviewed which lead to our current understanding of the role of intracellular cAMP in the differentiation of both stalk and spore cells. 相似文献
14.
E. A. Volpe 《Cellular and molecular life sciences : CMLS》1992,48(5):500-503
The cytotoxic activity (CTA) of activated peritoneal macrophages (MP) on variant lines of Syrian hamster embryo (HE) cells of differing malignant characteristics was studied. The target cells were a line of low-malignant cells resulting from spontaneous transformation of HE cells in vitro (STHE strain), and malignant variants selected from them in vivo (STHE-LM-4, STHE-LM-8, and STHE-75/18 strains). In addition, we used cells of the HET-SR-1 strain; these are HE cells transformed in vitro by a tumorigenic Rous sarcoma virus (Schmidt-Ruppin strain, RSV-SR), or the TU-SR strain induced by RSV-SR in vivo. Thioglycollate-elicited peritoneal MP from Syrian hamsters were activated in vitro with bacterial levan, LPS or MDP and used as effector cells. MP-mediated cytolysis was determined by means of a 42-h radioactivity release assay with3H-thymidine-labeled target cells. We found that only the parental STHE cells were susceptible towards fully-activated MP-mediated CTA. All three of the in vivo-selected malignant variants of the STHE cell sublines, as well as the tumorigenic RSV-SR transformants, were resistant to cytolysis by activated MP. Non-activated thioglycollate-elicited MP did not lyse any of the tumor cells studied. 相似文献
15.
E A Volpe 《Experientia》1992,48(5):500-503
The cytotoxic activity (CTA) of activated peritoneal macrophages (MP) on variant lines of Syrian hamster embryo (HE) cells of differing malignant characteristics was studied. The target cells were a line of low-malignant cells resulting from spontaneous transformation of HE cells in vitro (STHE strain), and malignant variants selected from them in vivo (STHE-LM-4, STHE-LM-8, and STHE-75/18 strains). In addition, we used cells of the HET-SR-1 strain; these are HE cells transformed in vitro by a tumorigenic Rous sarcoma virus (Schmidt-Ruppin strain, RSV-SR), or the TU-SR strain induced by RSV-SR in vivo. Thioglycollate-elicited peritoneal MP from Syrian hamsters were activated in vitro with bacterial levan, LPS or MDP and used as effector cells. MP-mediated cytolysis was determined by means of a 42-h radioactivity release assay with 3H-thymidine-labeled target cells. We found that only the parental STHE cells were susceptible towards fully-activated MP-mediated CTA. All three of the in vivo-selected malignant variants of the STHE cell sublines, as well as the tumorigenic RSV-SR transformants, were resistant to cytolysis by activated MP. Non-activated thioglycollate-elicited MP did not lyse any of the tumor cells studied. 相似文献
16.
dng1 is a Dictyostelium homologue of the mammalian tumor suppressor ING gene. DNG1 protein localizes in the nucleus, and has a highly conserved PHD finger domain found in chromatin-remodeling proteins. Both dng1 disruption and overexpression impaired cell proliferation. In dng1-null cells, the progression of differentiation was delayed in a cell-density-dependent manner, and many tiny aggregates were formed. Exogenously applied cAMP pulses reversed the inhibitory effect caused by dng1 disruption on the aggregation during early development, but formation of tiny aggregates was not restored. dng1-overexpressing cells acquired the ability to undergo chemotaxis to cAMP earlier and exhibited enhanced differentiation. These phenotypes were found to be coupled with altered expressions of early genes such as cAMP receptor 1 (car1) and contact site A (csA). Furthermore, disordered histone modifications were demonstrated in dng1-null cells. These results suggest a regulatory role of dng1 in the transition of cells from growth to differentiation.Received 29 December 2004; received after revision 24 May 2005; accepted 26 May 2005 相似文献
17.
Summary Some effects of cAMP on replication of Semliki Forest Virus in chick embryo fibroblast cell cultures are described. Depending on concentration, the incorporation of [3H]-uridine into viral RNA or the formation of plaqueforming units is inhibited; the highest concentration tested was 8 mM. Cyclic AMP has an effect of its own and increases the Interferon action in the lower concentration ranges of Interferon (up to 1 unit/ml). The effect of cyclic AMP is fast, needs no induction and is also visible in late phases of viral replication. However, these experiments do not establish a causal relation between cAMP and Interferon.Work supported by the Swiss National Science Foundation, grants 3.1050 and 3.540. 相似文献
18.
The incubation of rat lung slices with paraquat ion (10(-4) M) had no effect on cAMP and cGMP levels of the rat lung slices. The preincubation with the same concentration of paraquat inhibited the cAMP elevating effect of histamine (10(-5) M) and isoproterenol (10(-5) M) and reduced the cGMP level to approximately 50% of the level obtained without preincubation with paraquat. 相似文献
19.
Linxia Zhang Linsey C. Seitz Amy M. Abramczyk Li Liu Christina Chan 《Cellular and molecular life sciences : CMLS》2011,68(5):863-876
The intracellular second messenger cAMP is frequently used in induction media to induce mesenchymal stem cells (MSCs) into
neural lineage cells. To date, an understanding of the role cAMP exerts on MSCs and whether cAMP can induce MSCs into functional
neurons is still lacking. We found cAMP initiated neuron-like morphology changes early and neural differentiation much later.
The early phase changes in morphology were due to cell shrinkage, which subsequently rendered some cells apoptotic. While
the morphology changes occurred prior to the expression of neural markers, it is not required for neural marker expression
and the two processes are differentially regulated downstream of cAMP-activated protein kinase A. cAMP enabled MSCs to gain
neural marker expressions with neuronal function, such as, calcium rise in response to neuronal activators, dopamine, glutamate,
and potassium chloride. However, only some of the cells induced by cAMP responded to the three neuronal activators and further
lack the neuronal morphology, suggesting that although cAMP is able to direct MSCs towards neural differentiation, they do
not achieve terminal differentiation. 相似文献
20.
Three cultured human cell lines, renal cancer cells (ACHN), bladder cancer cells (EJ), and fibroblasts transformed in culture by Co-60 gamma rays (KMST-6), when treated with interferon-beta, produced 1.5 to 4 times as much plasminogen activator as the untreated control cultures. This enhanced production of PA was inhibited by cycloheximide or actinomycin D. 相似文献