Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The human osteosarcoma cell line (OST-1-PF) can grow in protein-free Coon's modified Ham's F12 medium. Growth of the cells in protein-free medium was partially density-dependent and partially depressed by medium change. An extract and conditioned medium of OST-1-PF cells contained high mitogenic activity for BALB/c3T3 cells. The growth factor in the cells was purified and identified as a basic fibroblast growth factor (bFGF)--like factor on the basis of its elution profile on heparin-affinity chromatography and the result of immunoblotting. An unidentified factor in a conditioned medium eliciting most of the DNA synthesis-stimulating activity showed a weak affinity for heparin. Various additions, including serum and growth factors, stimulated the growth of OST-1-PF cells in protein-free medium. Of these factors, epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), acidic fibroblast growth factor (aFGF) and bFGF were the most potent mitogens. High-affinity receptors of EGF and FGF were found on the surface of these cells. These results indicate that autonomous growth of OST-1-PF cells in protein-free medium is mainly controlled by an intracellular mechanism.
 ...
PMID:Roles of various growth factors in growth of human osteosarcoma cells which can grow in protein-free medium. 158 71

The expression of a total of 58 cytokines, growth factors, and their corresponding receptors and bone matrix proteins was assessed using reverse transcription-linked polymerase chain reaction (RT-PCR) analysis to determine the similarity in the expression profile between clonal osteosarcoma-derived human osteoblast-like cell lines and primary human osteoblast-like cell cultures derived from human trabecular bone explants. The spectrum of cytokines, growth factors, and bone-related proteins expressed by three human osteosarcoma-derived cell lines, TE-85, MG-63, SaOS-2, and primary human osteoblast-like cells was found to be highly comparable and for the first time the expression of EGF, ECGF, FGF beta, oncostatin M, TNF beta, and SCF by human osteoblast-like cells was detected. Also the expression of several receptor types including IL-4R, IL-7R, IFN alpha/beta R, and SCFR was detected that has not been previously described for human osteoblast-like cells. For the factors examined, no qualitative variations in the expression profile were observed in the six primary human osteoblast-like cell cultures used in this study. Of the 58 factors examined, only 13 showed some degree of nonuniformity of expression between all of the three cell lines and primary cell cultures. These differences were seen especially in the expression of cytokine receptor mRNA and to a lesser extent with some cytokines. Differences in receptor expression would suggest that the possible spectrum of response to exogenously added factors, or even autocrine/ paracrine networks would be determined by the repertoire of receptors expressed by each cell type. Whether the differences are related to the status of cell maturation within the osteoblast development lineage or to their abberant regulation of expression cannot be concluded at this stage. However, this PCR-phenotyping approach rapidly provides a resource of information, which can be subsequently used for further in depth studies to facilitate the analysis of the molecular mechanisms, whereby the target gene of interest is modulated in a model cell line. In addition, this study indicates that at least based on the transcript expression profile of the factors analyzed, human osteosarcoma-derived osteoblast-like cells are useful as models for their nontransformed counterparts.
 ...
PMID:PCR phenotyping of cytokines, growth factors and their receptors and bone matrix proteins in human osteoblast-like cell lines. 892 41

Basic fibroblast growth factor (bFGF) lacks signal sequence and therefore the mechanism of its secretion is unknown. Multidrug resistance-associated protein (MRP) has been shown to transport a variety of molecules. Therefore, in this study we examined the role of MRP in the secretion of bFGF by osteogenic sarcoma MG-63 cells which spontaneously secrete bFGF. We show that MG-63 cells express MRP both at the protein and at the mRNA level. Furthermore, probenecid (a putative inhibitor of transport activity of MRP), in a concentration-dependent manner, inhibited secretion of bFGF from MG-63 cells with concomitant increase in intracellular contents of bFGF. These results suggest that MRP may have a possible role in the secretion of bFGF.
 ...
PMID:A possible role for multidrug resistance-associated protein in the secretion of basic fibroblast growth factor by osteogenic sarcoma cell line (MG-63). 982 53

We have previously reported the alternatively spliced transcripts of fibroblast growth factor 3 (FGFR3 ATs and MTs) derived by aberrant splicing and usage of cryptic splicing sites. Here, we describe a soluble variant of FGFR3 (FGFR3 AT-III) arising from skipping exons 8, 9, and 10 in human SaOS-2 osteosarcoma cell. This splicing event leads to the generation of an mRNA encoding a FGFR3 in which the COOH-terminal portion of the Ig-like-III domain and transmembrane domain are deleted while the remainder of the mature molecule is fused in-frame to the COOH-terminal cytoplasmic kinases domains. Sf9 cells transfected with the corresponding cDNA express the soluble form of FGFR3 AT-III into the condition medium and its secreted form was able to bind both FGF-1 and FGF-2 leading to loss of ligand binding specificity. These results indicate that the FGFR3 AT-III mRNAs are transcribed due to exon skipping with altered ligand binding specificity. These results suggest that the presence of soluble transcripts of FGFRs gene is a common feature due to mRNA splicing and this splicing plays an important role in the regulation of FGFRs function.
 ...
PMID:Identification and characterization of soluble isoform of fibroblast growth factor receptor 3 in human SaOS-2 osteosarcoma cells. 1190 72

Fibroblast growth factor-1 (FGF-1) has both extra- and intracellular functions. To identify intracellular binding partners for FGF-1, we isolated proteins from U2OS human osteosarcoma cells interacting specifically with FGF-1. One of the isolated proteins was identified as protein kinase CK2 (CK2). We here provide evidence that FGF-1 binds to both the catalytic alpha-subunit and to the regulatory beta-subunit of CK2. The interaction between FGF-1 and CK2 alpha and beta was characterized by surface plasmon resonance, giving K(D) values of 0.4 +/- 0.3 and 1.2 +/- 0.2 microM, respectively. By using a novel assay for intracellular protein interaction, FGF-1 and CK2 alpha are shown to interact in vivo. In vitro, FGF-1 and FGF-2 are phosphorylated by CK2, and the presence of FGF-1 or FGF-2 was found to enhance the autophosphorylation of CK2 beta. A correlation between the mitogenic potential of FGF-1 mutants and their ability to bind to CK2 alpha was observed. The possible involvement of CK2 in the FGF-induced stimulation of DNA synthesis is discussed.
 ...
PMID:Binding of FGF-1 variants to protein kinase CK2 correlates with mitogenicity. 1214 6

Tumor necrosis factor-alpha (TNF-alpha) is a major mediator of inflammatory responses in many diseases that inhibits bone formation and stimulates bone resorption. To determine molecular mechanisms involved in the suppression of bone formation we have analyzed the effects of TNF-alpha on BSP gene expression. Bone sialoprotein (BSP) is a mineralized tissue-specific protein that appears to function in the initial mineralization of bone. Previous studies have demonstrated that BSP mRNA expression is essentially restricted to fully-differentiated cells of mineralized connective tissues and that the expression of BSP is developmentally regulated. Treatment of rat osteosarcoma ROS 17/2.8 cells with TNF-alpha (10 ng/ml) for 24 h caused a marked reduction in BSP mRNA levels. The addition of antioxidant N-acetylcysteine (NAC; 20 mM) 30 min prior to stimulation with TNF-alpha attenuated the inhibition of BSP mRNA levels. Transient transfection analyses, using chimeric constructs of the rat BSP gene promoter linked to a luciferase reporter gene, revealed that TNF-alpha (10 ng/ml) suppressed expression in all constructs, including a short construct (pLUC3; nts -116 to +60), transfected into ROS17/2.8 cells. Further deletion analysis of the BSP promoter showed that a region within nts -84 to -60 was targeted by TNF-alpha, the effects which were inhibited by NAC and the tyrosine kinase inhibitor, herbimycin A (HA). Introduction of 2bp mutations in the inverted CCAAT box (ATTGG; nts -50 and -46), a putative cAMP response element (CRE; nts -75 to -68), and a FGF response element (FRE; nts -92 to -85) showed that the TNF-alpha effects were mediated by the CRE. These results were supported by gel mobility shift assays, using a radiolabeled double-stranded CRE oligonucleotide, which revealed decreased binding of a nuclear protein from TNF-alpha-stimulated ROS 17/2.8 cells. Further, the inhibitory effect of TNF-alpha on CRE DNA-protein complex was completely abolished by NAC or HA treatment. These studies, therefore, show that TNF-alpha suppresses BSP gene transcription through a tyrosine kinase-dependent pathway that generates reactive oxygen species and that the TNF-alpha effects are mediated by a CRE element in the proximal BSP gene promoter.
 ...
PMID:TNF-alpha suppresses bone sialoprotein (BSP) expression in ROS17/2.8 cells. 1239 13

Bone sialoprotein (BSP), an early marker of osteoblast differentiation, has been implicated in the nucleation of hydroxyapatite during de novo bone formation. Basic fibroblast growth factor (FGF2) is recognized as a potent mitogen for a variety of mesenchymal cells. In skeletal tissues, FGF2 produced by osteoblasts accumulates in the bone matrix and acts as an autocrine/paracrine regulator of bone cells. To determine the molecular mechanism of FGF2 regulation of osteogenesis, we have analyzed the effects of FGF2 on the expression of BSP in the rat osteosarcoma cell line ROS 17/2.8. FGF2 at 10 ng/ml, increased BSP mRNA levels approximately 4-fold; the stimulation was first evident at 3 hr, reached maximal levels at 6 hr. The stability of the BSP mRNA was not significantly affected by FGF2, suggesting that the increased mRNA was due to increased transcription. From transient transfection analyses using various BSP promoter-luciferase constructs, a FGF2 response element (FRE) (nts -92 to -85, "GGTGAGAA") was identified as a target of transcriptional activation by FGF2. Ligation of two copies of the FRE 5' to an SV40 promoter was sufficient to confer FGF responsive transcription. A sequence-specific protein-DNA complex, formed with a double-stranded oligonucleotide encompassing the FRE and nuclear extracts from ROS 17/2.8 cells, but not from fibroblasts, was increased following FGF2 stimulation. Several point mutations within the critical FRE sequence abrogated the formation of this complex and suppressed both basal and FGF2-mediated promoter activity. Thus, we have identified a novel FRE within the proximal promoter of the BSP gene that mediates both constitutive and FGF2-induced BSP transcription.
 ...
PMID:Identification of FGF2-response element in the rat bone sialoprotein gene promoter. 1295 82

Serum levels of endostatin, placental growth factor (PlGF), and fibroblast growth factors-1 and -2 (FGF-1 and FGF-2) were measured in 58 patients with primary osteosarcomas before therapy and in 21 healthy subjects. The incidence of serum FGF-1 in bone tumors was 2.5 times higher than in healthy individuals (p=0.004); significant levels of FGF-2, PlGF, and endostatin were detected in all examined subjects. The mean serum level of endostatin in healthy individuals was significantly lower than in the total group of patients with bone tumors (p=0.005). The level of FGF-1 in osteosarcomas was significantly higher than in chondrosarcomas (p<0.05). No appreciable differences in FGF-2 levels were detected in patients with tumors of different histological structure. The mean serum content of PlGF was virtually the same in healthy individuals and patients with bone tumors. A significant relationship between serum PlGF level and maximum tumor size (p=0.008) was detected in osteosarcoma. No relationships between the levels of FGF-1, FGF-2, PlGF, and endostatin were detected in healthy subjects and patients with primary tumors of the bones. Differences in 3-year overall survival values of patients with bone sarcomas with different initial serum levels of FGF-1 and endostatin were detected.
 ...
PMID:Endostatin, placental growth factor, and fibroblast growth factors-1 and -2 in the sera of patients with primary osteosarcomas. 2002 39