Membrane components that interact with epidermal growth factor (EGF) and transforming growth factors (TGFs) have been identified by covalent crosslinking to their respective 125I-labeled ligands. Under appropriate conditions, disuccinimidyl suberate or hydroxysuccinimidyl p-azidobenzoate cross-link receptor-bound 125I-labeled EGF to a 140- to 170-kilodalton (kDal) receptor species in membranes ...

A medium consisting of a rich basal nutrient mixture supplemented with bovine insulin (10 micrograms/ml), human transferrin (10 micrograms/ml), human cold-insoluble globulin (5 micrograms/ml), and ethanolamine (0.5 mM) supported the growth of the A431 human epidermoid cell line in the absence of serum with a generation time equal to that of cells in serum-containing medium. Addition of epiderma...

Human squamous cell carcinomas (SCC) frequently express elevated levels of epidermal growth factor receptor (EGFR). EGFR overexpression in SCC-derived cell lines correlates with their ability to invade in an in vitro invasion assay in response to EGF, whereas benign epidermal cells, which express low levels of EGFR, do not invade. EGF-induced invasion of SCC-derived A431 cells is inhibited by s...

Epothilones are a new class of natural and potent antineoplastic agents that stabilize microtubules. Although 12,13-epoxide derivatives are potent antiproliferative agents, the activities of the corresponding 12,13-olefin analogs are significantly decreased. These data were confirmed for two new analogs, 6-propyl-EpoB (pEB) and 6-propyl-EpoD (pED), in comparison with the natural compounds EpoB/...

The fungal metabolite balanol is a potent inhibitor of protein kinase A (PKA) and protein kinase C (PKC) in vitro that acts by competing with ATP for binding (K(i) approximately 4 nM); congeners of balanol show specificity for PKA over PKC. We have characterized the effects of balanol and 10"-deoxybalanol in intact cells to determine whether these compounds cross the cell membrane and whether t...

Epidermal growth factor (EGF) has been shown to radiosensitize A431 and other human squamous carcinoma cells with high numbers of surface EGF receptors. In this study of the mechanistic basis of EGF-induced radiosensitization, both EGF and ionizing radiation caused G1 phase arrests in cycling A431 cells, but only radiation caused a G2-M arrest. However, EGF enhanced the magnitude of this G2-M a...

BACKGROUND We previously showed the usefulness of a fused protein of human pancreatic ribonuclease1 (hRNase1) with human epidermal growth factor (hEGF) for molecular targeting of EGF receptor (EGFR)-overexpressing cells. In this study, the mechanisms underlying the inhibition of cell growth by RNase-EGF fused proteins was confirmed. MATERIALS AND METHODS Des.1-7 hRNase1 was genetically fused ...

An antitumor glycoprotein [streptococcal acidic glycoprotein (SAGP)] purified from an extract of Streptococcus pyogenes inhibited the growth of human epidermoid carcinoma A431 cells overexpressing epidermal growth factor receptor (EGFR) in a time- and a concentration-dependent manner. The antiproliferative effect of SAGP was diminished by preincubating the cells with pertussis toxin and by coad...

We examined effect of the tyrosine kinase inhibitor herbimycin A on A431 human epidermoid carcinoma cells which over-express epidermal growth factor (EGF) receptor. Herbimycin A inhibited the autophosphorylation of EGF-stimulated receptors in intact cells both time- and dose-dependently. The inhibition was found to be due to a decrease in the level of expression of the receptor amount, because ...

ErbB oncogenes drive the progression of several human cancers. Our study shows that in human carcinoma (A431) and glioma (U373) cells, the oncogenic forms of epidermal growth factor receptor (EGFR; including EGFRvIII) trigger the up-regulation of tissue factor (TF), the transmembrane protein responsible for initiating blood coagulation and signaling through interaction with coagulation factor V...