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EPIDERMAL GROWTH FACTOR BINDING BY MEMBRANES OF HUMAN RENAL CELL CARCINOMAS: ESTABLISHMENT OF AN EPIDERMAL GROWTH FACTOR RECEPTOR ASSAY FOR CLINICAL USE
Author(s) -
Yoshida Kenichiro,
Tosaka Akira
Publication year - 1994
Publication title -
international journal of urology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 67
eISSN - 1442-2042
pISSN - 0919-8172
DOI - 10.1111/j.1442-2042.1994.tb00057.x
Subject(s) - epidermal growth factor , incubation , receptor , membrane , binding site , growth factor , dissociation constant , cell surface receptor , epidermal growth factor receptor , endocrinology , cell culture , cell , cell membrane , medicine , biology , microbiology and biotechnology , biochemistry , genetics
In order to quantitate epidermal growth factor receptors (EGFR) in human renal cell carcinoma (RCC) tissues, the binding of isotope‐labeled epidermal growth factor ( 125 I‐EGF) to pooled membrane samples from human RCC was studied. Specific EGF binding to membranes at 4C reached a plateau after 2 h of incubation and remained constant up to 8 h; specific binding at 25C reached a plateau after 30 min of incubation, then decreased gradually. 125 I‐EGF binding to the membrane was displaced by both EGF and transforming growth factor‐aL, but not by insulin and basic fibroblast growth factor. Scatchard analysis of the specific EGF binding generated a straight line, indicating a single class of binding sites for EGF, with a dissociation constant (Kd) of 21.1 times10 10 M and a maximum number of binding sites of 57.2fmol/mg membrane protein. When the protein concentration in the incubation medium was adjusted from 0.71mg/ml to 2.84 mg/ml, Scatchard analysis revealed identical Kd values, and the maximum number of binding sites was proportional to the protein concentration. These results demonstrate the presence of EGFR on RCC membranes and indicate that these receptors can be studied quantitatively.