title: Aberrant expression of receptors for platelet-derived growth factor in an anaplastic thyroid carcinoma cell line.
abstract: Receptors for platelet-derived growth factor (PDGF) have previously only been found on cells of mesenchymal and glial origin. This study shows PDGF receptors on an anaplastic thyroid carcinoma cell line, C 643, that was found to express thyroglobulin mRNA, confirming its origin from thyroid epithelium. Northern blot analysis of poly(A)+ RNA hybridized with a human PDGF B-type receptor cDNA probe revealed a 5.4-kilobase transcript in the C 643 cells. The existence of receptor protein on the cell surface was shown by immunofluorescence microscopy with a PDGF receptor monoclonal antibody. Binding experiments with 125I-labeled dimeric forms of PDGF indicated that the cells contain B-, but not A-, type PDGF receptors. The addition of PDGF to C 643 membranes in the presence of [32P]ATP induced phosphorylation of the receptor. A polyclonal PDGF B-type receptor peptide antiserum was used to immunoprecipitate a receptor protein from metabolically labeled C 643 cells; the receptor was found to be 5-10 kDa larger than that in normal human fibroblasts. Removal of N-linked carbohydrates using endoglycosidase H resulted in deglycosylated receptor proteins of similar size in C 643 cells and fibroblasts, indicating differences in glycosylation patterns of the two receptor proteins. The aberrant expression of receptors might be crucial in tumor development by conferring a selective growth advantage to the cancer cells.
authors.affiliation: Department of Pathology, University of Uppsala, Sweden.
authors.forename: N E
authors.initials: NE
authors.lastname: Heldin
authors.forename: B
authors.initials: B
authors.lastname: Gustavsson
authors.forename: L
authors.initials: L
authors.lastname: Claesson-Welsh
authors.forename: A
authors.initials: A
authors.lastname: Hammacher
authors.forename: J
authors.initials: J
authors.lastname: Mark
authors.forename: C H
authors.initials: CH
authors.lastname: Heldin
authors.forename: B
authors.initials: B
authors.lastname: Westermark
mesh_terms: D015152:Blotting, Northern; D002277:Carcinoma / Q000235:genetics*; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D006801:Humans; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000378:metabolism; D017479:Receptors, Platelet-Derived Growth Factor; D013954:Thyroglobulin / Q000235:genetics; D013964:Thyroid Neoplasms / Q000235:genetics*
chemical_list: D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D013954:Thyroglobulin; D017479:Receptors, Platelet-Derived Growth Factor