title: Differential role of transforming growth factor-alpha in two human colon-carcinoma cell lines.
abstract: Antibodies to epidermal-growth-factor receptor (EGF) and transforming growth factor-alpha (TGF-alpha) were used to determine the role of endogenous TGF-alpha in the growth of 2 human colon-carcinoma cell lines. Both the GEO and HCT 116 colon-carcinoma cell lines secrete similar levels of TGF-alpha and have similar numbers of low-affinity binding sites for EGF. However, the HCT 116 cells lack the high-affinity EGF binding site present on the GEO cells. The anti-EGF receptor antibodies effectively blocked the binding of 125I-EGF to the GEO and HCT 116 cell lines. Growth of the GEO cell line was inhibited 50-80% by the anti-EGF receptor and anti-TGF-alpha antibodies. When the same antibodies, in sufficient amounts to block binding of TGF-alpha to the cells, were added to the HCT 116 cell line, no effect on growth was seen. These results suggest that while the GEO cell line utilizes TGF-alpha in an autocrine manner, the TGF-alpha secreted by the HCT 116 cells apparently does not play a role in the growth of these cells.
authors.affiliation: Department of Pharmacology, Baylor College of Medicine, Houston, TX 77030.
authors.forename: L F
authors.initials: LF
authors.lastname: Watkins
authors.forename: A E
authors.initials: AE
authors.lastname: Levine
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D004815:Epidermal Growth Factor / Q000378:metabolism; D066246:ErbB Receptors / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D006801:Humans; D051379:Mice; D016211:Transforming Growth Factor alpha / Q000276:immunology / Q000502:physiology*
chemical_list: D000906:Antibodies; D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor; D066246:ErbB Receptors