title: Amplification and expression of the TGF-alpha, EGF receptor and c-myc genes in four human oesophageal squamous cell carcinoma lines.
abstract: We have previously shown that four human oesophageal squamous cell carcinoma (SCC) cell lines secrete significant quantities of transforming growth factor alpha (TGF-alpha) in vitro. Three of these lines are known to produce supernumerary low-affinity epidermal growth factor receptors (EGF-Rs). Using an 125I-EGF competitive binding assay and Scatchard analysis, we show that the fourth also overproduces low-affinity receptors. According to slot blot DNA analyses, the secretion of high levels of TGF-alpha is not associated with amplification of the TGF-alpha gene, and hyperproduction of the EGF-R is correlated with receptor gene amplification. Western blot analyses show that the c-Myc protein is overexpressed in two of the cell lines; and Southern and Northern blot analyses indicate that this overexpression occurs independently of c-myc gene amplification. Our results are consistent with an autocrine role for TGF-alpha and EGF-R in oesophageal carcinogenesis and support the possibility that c-myc overexpression may be required for the in vivo tumourigenicity of cells that produce high levels of TGF-alpha and the EGF-R.
authors.affiliation: Department of Zoology, University of the Witwatersrand, South Africa.
authors.forename: G J
authors.initials: GJ
authors.lastname: Jones
authors.forename: N S
authors.initials: NS
authors.lastname: Heiss
authors.forename: R B
authors.initials: RB
authors.lastname: Veale
authors.forename: A L
authors.initials: AL
authors.lastname: Thornley
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D066246:ErbB Receptors / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D004938:Esophageal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D005784:Gene Amplification; D015972:Gene Expression Regulation, Neoplastic; D016259:Genes, myc; D006801:Humans; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D016211:Transforming Growth Factor alpha / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D014407:Tumor Cells, Cultured
chemical_list: D009363:Neoplasm Proteins; D016211:Transforming Growth Factor alpha; D066246:ErbB Receptors