Characteristics of specific binding of epidermal growth factor (EGF) on human tumor cell lines.

Abstract

Using seventeen human tumor cell lines derived from a variety of tissues, specific binding sites for epidermal growth factor (EGF), a mouse submandibular glandderived growth factor, has been characterized. A significant amount of membranebound EGF receptors, although considerably varied, was demonstrated in all the tumor cell lines studied. Epidermoid carcinoma appeared to have more EGF receptors than adenocarcinoma. One small cell carcinoma of the lung, one choriocarcinoma of the stomach and three bone tumors also possessed EGF recptors comparable to those of epidermoid carcinoma, while one adenoacanthoma of the stomach had less EGF receptors comparable to adenocarcinoma. Among a variety of phorbol esters tested, tetradecanoyl phorbol acetate, a potent tumor promotor, was shown to be the most effective compound in inhibiting ¹²⁵I-labeled EGF binding to its receptors. Our results indicate that human tumor cells contain varying amounts of membranebound receptors for EGF and that phorbol esters interact with these EGF receptor sites. However, the relationship between EGF receptor sites on tumor cells and cellular proliferation and/or differentiation awaits further study.