Growth stimulation of A431 cells by epidermal growth factor: identification of high-affinity receptors for epidermal growth factor by an anti-receptor monoclonal antibody.

• DOI: 10.1073/pnas.80.5.1337
• Publication Date: 2006-05-31T09:18:22Z
• Authors: T Kawamoto; J D Sato; A Le; J Polikoff; G H Sato; J Mendelsohn
• Keywords: A431 cells; Epidermoid carcinoma

Epidermal growth factor (EGF) at 3 nM maximally inhibits the proliferation of A431 epidermoid carcinoma cells. We show that lower concentrations, in range 3-100 pM, EGF has a mitogenic effect on In presence 100 anti-EGF-receptor monoclonal IgG (designated 528), which cell and blocks greater than 95% binding, becomes for cells concentrations up to nM. These results suggest minor population high-affinity receptors may be involved stimulation proliferation. Saturation binding assays with 125I-labeled indicate approximately equal 0.1-0.2% are bind an estimated Kd 7 X 10(-11) M. This affinity is nearly 2 orders magnitude higher remaining receptors. Although inhibited by nonsaturating amounts (3 nM), maximal inhibition 528 (approximately 70% EGF) requires saturating antibody 15 nM). Unlike EGF, rapid down-regulation not observed IgG. different mechanisms