title: Biological significance of aminopeptidase N/CD13 in thyroid carcinomas.
abstract: Aminopeptidase N (APN)/CD13 is a transmembrane ectopeptidase expressed on a wide variety of cells. However, the precise function of APN/CD13 in tumor cells and the relationship of APN/CD13 to thyroid cancer remain unclear. In our study, we quantified the expression of APN/CD13 and additionally dipeptidyl peptidase IV (DPIV)/CD26 in thyroid carcinoma cell lines and in tissues of patients with thyroid carcinomas. Undifferentiated anaplastic thyroid carcinomas expressed more APN/CD13 than differentiated thyroid carcinomas. DPIV/CD26 showed an opposite expression pattern. We detected higher levels of DPIV/CD26 in follicular thyroid carcinomas (FTCs) and papillary thyroid carcinomas than in undifferentiated anaplastic thyroid carcinomas. In the undifferentiated thyroid carcinoma cell line 1736, APN/CD13 mRNA expression could be increased by epidermal growth factor, basic fibroblast growth factor, interleukin-6, and tumor necrosis factor alpha. FTC-133 cells stably transfected with an expression vector for APN-enhanced green fluorescent protein showed a higher migration rate than FTC-133 cells transfected with the enhanced green fluorescent protein-control plasmid. Overexpression of APN/CD13 in stably transfected cells is associated with down-regulation of N-myc down-regulated gene (NDRG)-1, melanoma-associated antigen ME491/CD63, and DPIV/CD26 gene expression. Inhibition of APN/CD13 mRNA expression by small interfering RNA induced NDRG-1, ME491/CD63, and DPIV/CD26 mRNA expression in cells of the undifferentiated thyroid carcinoma cell line C643. We conclude that APN/CD13-associated down-regulation of NDRG-1, ME491/CD63, and DPIV/CD26 in thyroid carcinoma cells is an important step of tumor progression to more malignant phenotypes, and we underline the important role of APN/CD13 as mediator in a multimolecular process regulating cell migration.
authors.affiliation: Institute of Medical Immunology, University of Halle-Wittenberg, Halle, Germany. astris.kehlen@medizin.uni-halle.de
authors.forename: Astrid
authors.initials: A
authors.lastname: Kehlen
authors.forename: Uwe
authors.initials: U
authors.lastname: Lendeckel
authors.forename: Henning
authors.initials: H
authors.lastname: Dralle
authors.forename: Jürgen
authors.initials: J
authors.lastname: Langner
authors.forename: Cuong
authors.initials: C
authors.lastname: Hoang-Vu
mesh_terms: D000328:Adult; D000368:Aged; D018826:CD13 Antigens / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D002277:Carcinoma / Q000201:enzymology* / Q000235:genetics / Q000276:immunology / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D018819:Dipeptidyl Peptidase 4 / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D015850:Interleukin-6 / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D013964:Thyroid Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000276:immunology / Q000473:pathology; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D015850:Interleukin-6; D004815:Epidermal Growth Factor; D018826:CD13 Antigens; D018819:Dipeptidyl Peptidase 4