PubMed Health⌕ Search

Biomedical subjects

D Marme

Publications and source records attributed to D Marme.

7 recordsLinked to original sources
PubMed2000

Inhibition of vascular endothelial growth factor expression in HEC1A endometrial cancer cells through interactions of estrogen receptor alpha and Sp3 proteins.

Treatment of HEC1A endometrial cancer cells with 10 nm 17beta-estradiol (E2) resulted in decreased vascular endothelial growth factor (VEGF) mRNA expression, and a similar response was observed using a construct, pVEGF1, containing a VEGF gene promoter insert from -2018 to +50. In HEC1A cells transiently transfected with pVEGF1 and a series of deletion plasmids, it was shown that E2-dependent down-regulation was dependent on wild-type estrogen receptor alpha (ERalpha) and reversed by the anti-estrogen ICI 182, 780, and this response was not affected by progestins. Deletion analysis of the VEGF gene promoter identified an overlapping G/GC-rich site between -66 to -47 that was required for decreased transactivation by E2. Protein-DNA binding studies using electrophoretic mobility shift and DNA footprinting assays showed that both Sp1 and Sp3 proteins bound this region of the VEGF promoter. Coimmunoprecipitation and pull-down assays demonstrated that Sp3 and ERalpha proteins physically interact, and the interacting domains of both proteins are different from those previously observed for interactions between Sp1 and ERalpha proteins. Using a dominant negative form of Sp3 and transcriptional activation assays in Schneider SL-2 insect cells, it was confirmed that ERalpha-Sp3 interactions define a pathway for E2-mediated inhibition of gene expression, and this represents a new mechanism for decreased gene expression by E2.

Base Sequence↗
PubMed2000

Anthraquinones and betaenone derivatives from the sponge-associated fungus Microsphaeropsis species: novel inhibitors of protein kinases.

An undescribed fungus of the genus Microsphaeropsis, isolated from the Mediterranean sponge Aplysina aerophoba, produces two new betaenone derivatives (1, 2) and three new 1,3,6, 8-tetrahydroxyanthraquinone congeners (5-7). The structures of the compounds were established on the basis of NMR spectroscopic and mass spectrometric data and by CD spectroscopy. This is the first report wherein the (1)H and (13)C NMR data of the betaenone congeners are fully and unambiguously assigned on the basis of two-dimensional NMR spectroscopy. Furthermore, we describe the first elucidation of the absolute configuration of 1-(2'-anthraquinonyl)ethanols such as 5 and 6, by quantum chemical calculation of their circular dichroism (CD) and comparison with experimentally measured spectra. Moreover, it was shown that compounds 1, 5, 6, and 7 are inhibitors of PKC-epsilon, CDK4, and EGF receptor tyrosine kinases.

Animals↗
PubMed1999

[In Process Citation]

Solid tumors do not grow beyond a size of a few millimetres without supply of nutrients and growth factors by the vascular system. Only when tumors produce angiogenic growth factors new vessels are formed by sprouting of capillaries from the existing vascular system. The tumor can grow and tumor cells reach the circulation through these new and permeable vessels. The vascular endothelial growth factor (VEGF) is the most prominent angiogenic growth factor. VEGF is produced by almost all solid tumors: its receptors are expressed only on vascular endothelial cells and predominantly in vessels in the proximity of the tumor. Therefore, the VEGF/VEGF-receptor system is a target for anti-angiogenic cancer therapy. Experiments show that inhibition of the VEGF-mediated endothelial cell activation interferes with tumor growth and metastases formation. Appropriate therapeutic strategies are currently under clinical investigation.

Journal Article↗
PubMed1985

Characterisation of calmodulin from Drosophila heads.

Calmodulin from Drosophila heads has been purified to apparent electrophoretic homogeneity. It has the same characteristics as bovine brain calmodulin with respect to the migration upon polyacrylamide gel electrophoresis and maximal activation of a calmodulin-deficient cAMP phosphodiesterase. The amino acid composition resembles bovine brain calmodulin with the exception that trimethyllysine is absent and that it contains only one tyrosine. The tryptic peptide map of Drosophila calmodulin suggests some differences in the amino acid sequence as compared to bovine brain calmodulin. These proposed differences in the primary structure may explain why Drosophila calmodulin is less potent than bovine brain calmodulin in the activation of a cAMP phosphodiesterase from bovine brain.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1984

Calmodulin content and activity of Ca2+-ATPase and phospholipase A2 in rat Kupffer cells.

A protein resembling calmodulin was isolated from non-parenchymal and parenchymal cells of rat liver by affinity chromatography. The biological activity of the purified protein was assessed by the bovine brain cAMP phosphodiesterase assay. A highly sensitive radioimmunoassay as well as the cAMP phosphodiesterase method were employed to determine the calmodulin content of crude extracts from monolayer cultures of rat Kupffer cells and hepatocytes. An ATP-dependent, calmodulin-enhanced calcium transport was demonstrated in a membrane fraction of the non-parenchymal cells. Phospholipase A2 activity specific for 2-arachidonoyl phosphatide and with a pH optimum of 8.1 was measured in homogenized Kupffer cells; it was stimulated by agents previously shown to enhance prostaglandin synthesis in Kupffer cells, e.g. zymosan particles and lipopolysaccharide isolated from Salmonella minnesota. The increase in activity was completely prevented by pretreatment with or simultaneous addition of R 24571, a known calmodulin antagonist. However, if this inhibitor or calmodulin was added to the cell-free extract phospholipase A2 activity was not influenced. Phospholipase A1 activity could be detected at pH 5 only, showing a slight decrease in the homogenate of stimulated macrophages. Acyltransferase activity was high but independent of treatment of the Kupffer cells.

1-Acylglycerophosphocholine O-Acyltransferase↗
PubMed1983

Effects of amiprophosmethyl on massive and limited calcium loading of maize mitochondria.

In maize mitochondria the effect of the herbicide amiprophosmethyl was studied on massive and limited Ca2+-loading and on mitochondrial energy transduction. Under massive Ca2+-loading conditions amiprophosmethyl inhibited the Ca2+ transport system directly without a significant effect on the respiratory chain, the membrane potential or Ca2+ efflux. Under limited Ca2+-loading conditions an increased Ca2+ efflux was noted, which could be partially responsible for the inhibition of the net Ca2+ accumulation.

Calcium↗