Overexpression of the human EGF receptor confers an EGF-dependent transformed phenotype to NIH 3T3 cells

PP Di Fiore, JH Pierce, TP Fleming, R Hazan, A Ullrich… - Cell, 1987 - cell.com
PP Di Fiore, JH Pierce, TP Fleming, R Hazan, A Ullrich, CR King, J Schlessinger
Cell, 1987cell.com
The epidermal growth factor receptor (EGFR) gene is frequently amplified and/or
overexpressed in human malignancies. To investigate the biological effects of Its
overexpression, we constructed a eukaryotic vector containing human EGFR cDNA.
Introduction of this construct led to reconstitution of functional EGF receptors in NR6 mutant
cells, which are normally devoid of this receptor. Transfection of NIH 3T3 resulted in no
significant alterations in growth properties. However, EGF addition led to the formation of …
Summary
The epidermal growth factor receptor (EGFR) gene is frequently amplified and/or overexpressed in human malignancies. To investigate the biological effects of Its overexpression, we constructed a eukaryotic vector containing human EGFR cDNA. Introduction of this construct led to reconstitution of functional EGF receptors in NR6 mutant cells, which are normally devoid of this receptor. Transfection of NIH 3T3 resulted in no significant alterations in growth properties. However, EGF addition led to the formation of densely growing transformed foci in liquid culture and colonies in semisolid medium. NIH 3T3-EGFR clonal lines, which expressed the EGF at 500-to lOOO-fold levels over control NIH 3T3 cells, demonstrated a marked increase in DNA synthesis in response to EGF. Thus EGF receptor overexpression appears to amplify normal EGF signal transduction. Finally, high levels of EGFR expression, which conferred a transformed phenotype to NIH 3T3 cells in the presence of ligand, were demonstrated in representative human tumor cell lines that contained amplified copies of the EGFR gene.
The profound alterations induced by activated cellular transforming genes are similar to the growth-promoting actions of hormones and growth factors. Recent evidence has established a direct link between oncogene products and either growth factors or growth factor receptors. The v-sis oncogene is derived from the gene encoding the B chain of the platelet-derived growth factor (Doolittle et al., 1983; Waterfield et al., 1983), while the ve &B and v-fms oncogenes are derived from the genes encoding epidermal growth factor (EGF; Downward et al., 1984) and colony stimulating factor-l (CSF-1; Sherr et al., 1985) receptors, respectively.
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