title: Epidermal growth factor inhibits the proliferation of a human endometrial carcinoma cell line.
abstract: Specific epidermal growth factor (EGF) receptors were measured in RL95-2 human endometrial carcinoma cells. At 37 C, binding of 125I-labeled EGF was associated with marked ligand internalization. Maximal cell surface binding occurred within 10 min. Bound [125I]EGF was partially degraded to low mol wt products, and this degradation was blocked by the lysosomotropic compound ammonium chloride. At 4 C, maximal cell surface binding occurred at 3 h. Scatchard analysis of data obtained after 3 h at 4 C revealed a single order of binding sites with a Kd of 1.8 nM and approximately 150,000 surface receptors/cell. EGF, at a concentration of 0.83 nM, inhibited the proliferation of RL95-2 cells. Inhibition was reversible and was associated with morphological changes leading to a fusiform appearance of the growth-arrested cells. These findings indicate that RL95-2 human endometrial carcinoma cells bind, internalize, and degrade EGF in a manner similar to that described for other target cells for EGF action. The ability of EGF to inhibit the growth of RL95-2 cells supports the hypothesis that this type of inhibition is dependent on postreceptor events, rather than on the presence of an overabundance of EGF receptors.
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors; D005260:Female; D006801:Humans; D007700:Kinetics; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013696:Temperature; D014594:Uterine Neoplasms / Q000378:metabolism*
chemical_list: D011956:Receptors, Cell Surface; D004815:Epidermal Growth Factor; D066246:ErbB Receptors