Epidermal growth factor (EGF) receptor is inversely related to ex pression of estrogen receptor (ER) and progesterone receptor in primary breast tumors and is a negative predictor for response to endocrine therapy. To investigate a possible causal role of EGF receptor expres sion in breast cancer progression to hormone independence, we have created an experimental cell system. Epidermal growth ...

Epidermal growth factor (EGF), after binding to its receptor, activates a tyrosine-specific protein kinase which phosphorylates several substrates, including the EGF receptor itself. The effects of a photoaffinity analogue of ATP, 3'-O-(3-[N-(4-azido-2-nitrophenyl)amino]propionyl)adenosine 5'-triphosphate (arylazido-beta-alanyl-ATP) on the EGF-dependent protein kinase in A431 human tumour cell ...

Gangliosides have been described as modulators of growth factor receptor activity and subsequent cellular function. Due to the lower-pH environment found in tumor cells, ganglosides are thought to be formed (at least to some extent) into their lactone forms. The aim of the study was to analyze the mode of action of the lactone of the ganglioside GM3 on epidermal growth factor (EGF) signaling in...

OBJECTIVE To determine the molecular mechanism underlying the synergistic response of mitogen-activated protein kinase phosphatase-1 (MKP-1), which is induced by thrombin and epidermal growth factor (EGF). METHODS AND RESULTS MKP-1 induction by thrombin (approximately 6-fold) was synergistically increased (approximately 18-fold) by cotreatment with EGF in cultured endothelial cells. EGF alone...

The epidermal growth factor receptor (HER1) has been implicated in regenerative growth and proliferative diseases of the human bladder epithelium (urothelium), however a cognate HER1 ligand that can act as a growth factor for normal human urothelial cells (HUC) has not been identified. Here we show that heparin-binding EGF-like growth factor (HB-EGF), an activating HER1 ligand, is an autocrine ...

The role of epidermal growth factor (EGF) in the regulation of estrogen receptor(ER) gene expression in the human breast cancer cell line MCF-7 was investigated. Treatment of cells with 0·4 ng/ml EGF resulted in an approximately 60% decrease in ERprotein concentration by 6 h and the amount of receptor remained suppressed for 24 h. Ligand binding assays demonstrated that the decrease in ERprotei...

Recent evidence suggests that the EGF receptor oligomerizes or clusters in cells even in the absence of agonist ligand. To assess the status of EGF receptors in live cells, an EGF receptor fused to eGFP was stably expressed in CHO cells and studied using fluorescence correlation spectroscopy and fluorescent brightness analysis. By modifying FIDA for use in a two-dimensional system with quantal ...

Activated EGF (epidermal growth factor) receptors are removed from the cell surface via endocytosis and subsequent degradation in the lysosome. This ultimately attenuates EGF receptor signals and diminishes the level of cell activation. The mechanisms underlying the EGF receptor down-regulation are beginning to be elucidated at the molecular level. Recent reports have indicated that receptor mo...