title: Differential regulation of syndecan expression by osteosarcoma cell lines in response to cytokines but not osteotropic hormones.
abstract: Bone cells are regulated by interactions with both growth factors and components of the extracellular matrix (ECM). Syndecans are cell-surface heparan sulfate proteoglycans known to play a role in cell adhesion and migration, and binding of growth factors. This study was performed to investigate the expression of syndecans by osteoblasts. Reverse transcription-linked polymerase chain reaction (RT-PCR) and Northern analysis detected syndecan transcripts in the human osteosarcoma cell lines MG-63, TE-85, SaOS-2, and U2OS; human osteoblast-like cells; rat calvarial osteoblasts; and in human bone. Western blot analysis of proteoglycans from MG-63 and TE-85 cells detected multiple heparan sulfate proteoglycan core proteins consistent with syndecan expression. Regulation of syndecan-1, -2, and -4 expression was investigated in TE-85, MG-63, and SaOS-2 cells, in response to interleukin (IL)-1beta, and IL-6, parathyroid hormone [PTH(1-34)], and 1,25(OH)2-vitamin D3. Northern analysis demonstrated that in the osteosarcoma cell lines there was no regulation of syndecan transcript levels in response to PTH(1-34) or 1,25(OH)2-vitamin D3 for 24 or 48 h. In contrast, when MG-63 and SaOS-2 cells were incubated with IL-1beta (0.01-10 ng/mL) and IL-6 (0.1-50 ng/mL) there was a dose-dependent decrease in mRNA levels for syndecan-1 and -2 at 24 and 48 h, but in response to IL-1beta upregulation in the levels of syndecan-4 transcripts. In addition, Northern analysis was performed on RNA isolated from neonatal rat calvarial osteoblasts cultured under conditions that promote osteogenesis for 0, 5, 13, 21, and 35 days. Syndecan-1 expression was observed to decrease during the culture period, syndecan-2 transcript levels increased, and there appeared to be no overall change in syndecan-4 levels. Controlled expression of syndecans by cells of the osteoblast lineage may be important in the regulation of osteoblastic proliferation and differentiation.
authors.affiliation: Department of Biology, University of York, UK. m.a.birch@ncl.ac.uk
authors.forename: M A
authors.initials: MA
authors.lastname: Birch
authors.forename: T M
authors.initials: TM
authors.lastname: Skerry
mesh_terms: D000818:Animals; D001483:Base Sequence; D002117:Calcitriol / Q000494:pharmacology; D002460:Cell Line; D016207:Cytokines / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D019812:Heparan Sulfate Proteoglycans / Q000096:biosynthesis; D006728:Hormones / Q000494:pharmacology*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D015850:Interleukin-6 / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000235:genetics*; D015345:Oligonucleotide Probes / Q000235:genetics; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism*; D012516:Osteosarcoma / Q000235:genetics / Q000378:metabolism; D010281:Parathyroid Hormone / Q000494:pharmacology; D011509:Proteoglycans / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053668:Syndecan-1; D053667:Syndecans; D014407:Tumor Cells, Cultured
chemical_list: D016207:Cytokines; D019812:Heparan Sulfate Proteoglycans; D006728:Hormones; D007375:Interleukin-1; D015850:Interleukin-6; D008562:Membrane Glycoproteins; D015345:Oligonucleotide Probes; D010281:Parathyroid Hormone; D011509:Proteoglycans; D012333:RNA, Messenger; C508241:SDC1 protein, human; C508243:Sdc1 protein, rat; D053668:Syndecan-1; D053667:Syndecans; D002117:Calcitriol