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Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Multilayered coatings composed of mixtures of HA and P2O5-based bioactive glasses are of potential clinical benefit in orthopaedic and dental surgery. Pre-immersion of these materials has been reported to further enhance their efficacy in vivo, although the precise biological effects of this treatment are not yet known. In this study we have therefore prepared double-layer plasma-sprayed coatings and evaluated the effects of pre-immersion on the growth and function of human osteosarcoma cells in vitro, using the MTT assay and flow cytometry analysis, respectively. The results showed that the increase in numbers of viable cells was the same or elevated following incubation on the pre-immersed HA and glass-reinforced HA coatings compared with the non-immersed materials. In addition, the expression of bone sialoprotein and fibronectin, two key connective tissue antigens, was up-regulated in cultures grown on the pre-immersed surfaces compared with the non-treated materials. Moreover, cell numbers and antigen expression both improved as the proportion of glass increased, particularly in the pre-immersed samples. Our findings thus suggest that the immersion treatment of these materials appeared to improve the response of these bone-like cells.
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PMID:Flow cytometry analysis of the effects of pre-immersion on the biocompatibility of glass-reinforced hydroxyapatite plasma-sprayed coatings. 1072 50

Osteosarcoma cells are useful for investigating bone metabolism as malignant counterpart of osteoblasts. In hematogenous metastases of osteosarcoma cells, the cells need to adjust to various changes in pericellular environment. The changes in pericellular environment may change intracellular environment and consequently the secretion of matrix metalloproteinases (MMPs) which destroy extracellular matrices. In this report, a new cell line, KOS-1, derived from human osteoblastic osteosarcoma was established, and we assumed various culture conditions containing ingredients of the extracellular matrix to make a comparative study on MMPs detected from the culture supernatants. A wide spectrum of MMPs, including MMP-1 and -3 which were increased in the presence of interleukin 1 beta, was detected in this cell line. Production of MMP-1, the enzyme which decomposes types I, II, III and X collagen, by the cells, was increased in the presence of type I collagen. MMP-3 (stromelysin-1) which degrades types III and IV collagen, laminin, fibronectin, proteoglycan, etc. was produced more abundantly in the presence of type IV collagen. MMP-2 (72-kd type IV collagenase/gelatinase A) activity was found to be increased in the presence of gelatin and type IV collagen. The MMPs production in cultured osteosarcoma cells was changed depending on the culture conditions. This indicates that the same osteosarocma cells produce different amounts and kinds of enzymes involved in local infiltration and remote metastases and increase the production of the enzymes most required under a specific environment.
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PMID:Establishment of an osteoblastic osteosarcoma cell line and effects of cell culture conditions on secretion of matrix metalloproteinases from the cultured osteosarcoma cells. 1094 49

Lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) are produced during cell activation and have multiple effects on cells. A family of seven transmembrane-spanning domain G-protein-coupled receptors, named Edg, mediate these effects of LPA and S1P. In this study, transient overexpression of Edg-2 sensitized MG63 human osteosarcoma cells to both LPA- and S1P-mediated stimulation of fibronectin matrix deposition and actin stress fiber formation. Both lipids were active in the 1-20 nM concentration range on cells transfected with Edg-2 as compared to the 10-200 nM range on mock-transfected cells. The signaling pathway for matrix deposition by Edg-2-transfected cells was Rho dependent. Overexpression of Edg-2 also caused a tenfold decrease in the concentration of either LPA or S1P that activated MAPKinase (Erkl/2) in MG63 cells. LPA- or S1P-stimulated activation of Erkl/2 was Gi dependent. These results indicate that, in MG63 cells, Edg-2 mediates actin stress fiber formation, fibronectin matrix assembly, and MAPKinase activation in response to either LPA or S1P.
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PMID:Differential stimulation of signaling pathways initiated by Edg-2 in response to lysophosphatidic acid or sphingosine-1-phosphate. 1096 47

We have investigated the effect of transforming growth factor-beta1 (TGF-beta1) on the in vitro adhesion activity of the rat osteosarcoma cell lines (ROS 17/2.8) to extracellular matrix substrata, including fibronectin, type I and IV collagen, as well as laminin. The interaction of Arg-Gly-Asp (RGD) and rhodostomin, an RGD containing snake venom, with TGF-beta1 on the cell adhesion was also evaluated. The results showed that incubation with various concentration of TGF-beta1 (1-15 ng/ml) significantly increased the adhesion activity (1.4 to 2.5 folds) of ROS 17/2.8 to fibronectin and type I collagen (p<0.01), whereas the adhesion activity to laminin and type IV collagen was slightly elevated (1.1 to 1.5 folds). The peak effect of TGF-beta1 on the cell adhesion occurred after pretreatment of ROS 17/2.8 with TGF-beta1 for 6 hours. Treatment with Arg-Gly-Asp-Ser (RGDS) and rhodostomin effectively suppressed the TGF-beta1-enhanced adhesion activity to fibronectin and type I collagen. This study demonstrated that the up-regulated cell adhesion activity of ROS 17/2.8 cells by the TGF-beta1 can be inhibited by the rhodostomin.
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PMID:Rhodostomin inhibits the transforming growth factor-beta1-enhanced adhesion activity of ROS 17/2.8 osteosarcoma cells. 1099 55

F1 is an adhesin of Streptococcus pyogenes which binds the N-terminal 70-kDa region of fibronectin with high affinity. The fibronectin binding region of F1 is comprised of a 43-residue upstream domain and a repeat domain comprised of five tandem 37-residue sequences. We investigated the effects of these domains on the assembly of fibronectin matrix by human dermal fibroblasts, MG63 osteosarcoma cells, or fibroblasts derived from fibronectin-null stem cells. Subequimolar or equimolar concentrations of recombinant proteins containing both the upstream and repeat domains or just the repeat domain enhanced binding of fibronectin or its N-terminal 70-kDa fragment to cell layers; higher concentrations of these recombinant proteins inhibited binding. The enhanced binding did not result in greater matrix assembly and was caused by increased ligand binding to substratum. In contrast, recombinant or synthetic protein containing the 43 residues of the upstream domain and the first 6 residues from the repeat domain exhibited monophasic inhibition with an IC(50) of approximately 10 nm. Truncation of the 49-residue sequence at its N or C terminus caused loss of inhibitory activity. The 49-residue upstream sequence blocked incorporation of both endogenous cellular fibronectin and exogenous plasma fibronectin into extracellular matrix and inhibited binding of 70-kDa fragment to fibronectin-null cells in a fibronectin-free system. Inhibition of matrix assembly by the 49-mer had no effect on cell adhesion to substratum, cell growth, formation of focal contacts, or formation of stress fibers. These results indicate that the 49-residue upstream sequence of F1 binds in an inhibitory mode to N-terminal parts of exogenous and endogenous fibronectin which are critical for fibronectin fibrillogenesis.
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PMID:A 49-residue peptide from adhesin F1 of Streptococcus pyogenes inhibits fibronectin matrix assembly. 1132 41

Tissue transglutaminase (tTG) is a calcium-dependent and guanosine 5'-triphosphate (GTP) binding enzyme, which catalyzes the post-translational modification of proteins by forming intermolecular epsilon(gamma-glutamyl)lysine cross-links. In this study, human osteoblasts (HOBs) isolated from femoral head trabecular bone and two osteosarcoma cell lines (HOS and MG-63) were studied for their expression and localization of tTG. Quantitative evaluation of transglutaminase (TG) activity determined using the [1,4 14C]-putrescine incorporation assay showed that the enzyme was active in all cell types. However, there was a significantly higher activity in the cell homogenates of MG-63 cells as compared with HOB and HOS cells (p < 0.001). There was no significant difference between the activity of the enzyme in HOB and HOS cells. All three cell types also have a small amount of active TG on their surface as determined by the incorporation of biotinylated cadaverine into fibronectin. Cell surface-related tTG was further shown by preincubation of cells with tTG antibody, which led to inhibition of cell attachment. Western blot analysis clearly indicated that the active TG was tTG and immunocytochemistry showed it be situated in the cytosol of the cells. In situ extracellular enzyme activity also was shown by the cell-mediated incorporation of fluorescein cadaverine into extracellular matrix (ECM) proteins. These results clearly showed that MG-63 cells have high extracellular activity, which colocalized with the ECM protein fibronectin and could be inhibited by the competitive primary amine substrate putrescine. The contribution of tTG to cell surface/matrix interactions and to the stabilization of the ECM of osteoblast cells therefore could by an important factor in the cascade of events leading to bone differentiation and mineralization.
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PMID:Characterization of tissue transglutaminase in human osteoblast-like cells. 1149 70

The purpose of the present work was to examine the effect of different Ti-6Al-4V surface treatments on osteoblasts behaviour. Previous work in this laboratory has demonstrated that an ageing treatment reduces metal ion release from this alloy compared to standard passivation procedures. In this study. human osteosarcoma MG-63 were used in short-term in vitro tests to assay for cell viability and cell proliferation at 12, 24 and 72 h while SaOS-2 were used in long-term in vitro tests to assay for osteonectin, osteopontin, osteocalcin gene expression, total protein amount (TP). alkaline phosphatase activity (ALP) and fibronectin production (FN) for 1-4 weeks. Epifluorescence microscopy was used to observe SaOS-2 cell morphology. After 24h, there was no difference in MG-63 cell viability proliferation or in SaOS-2 cell morphology between the different surface treatments. For the long-term tests, the aged Ti-6Al4V induced significantly higher cell proliferation than the control Ti-6Al-4V at 72h. At week 1, no difference in the osteonectin, osteopontin, and osteocalcin gene expression was found between samples. The peak of ALP activity appeared earlier at week 2 for the control surface compared with the passivated and aged surfaces. The early increase in ALP activity for the control sample could be a compensatory effect of decreased osteoblasts proliferation. There was no difference in the expression of FN for the different surface treatments. Our present results showed that the different surface treatments, which induced different metal ion release kinetics and surface properties, influenced the cell proliferation and ALP activity of osteoblast cells. Aluminium ions release kinetics as well as presence of vanadium ions may play a major role in influencing the osteoblasts behaviour in the present study.
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PMID:Effect of different Ti-6Al-4V surface treatments on osteoblasts behaviour. 1182 40

Thrombospondin-1 (TSP-1) is an extracellular glycoprotein that is involved in a variety of physiological processes such as tumor cell adhesion, invasion, and metastasis. It has been hypothesized that TSP-1 provides an adhesive matrix for osteosarcoma cells. Here we present data showing that TSP-1 can promote cell substrate adhesion to U2OS and SAOS cells through the alpha 4 beta 1 integrin. The dose-dependent adhesion to TSP-1 was inhibited by anti-integrin antibodies directed against the alpha 4 or beta 1 subunit, but not by control antibodies against other integrins. To localize the potential alpha 4 beta 1-binding site within the TSP-1 molecule, the protein was subjected to limited proteolysis with chymotrypsin in the absence of calcium. The stable 70-kDa core fragment produced under these conditions promoted alpha 4 beta 1-dependent osteosarcoma cell adhesion in a manner similar to that of the intact protein. Moreover adhesion experiments with neutralizing antibodies revealed that the adhesion was totally dependent on the alpha 4 beta 1 interaction. Further blocking experiments with potential inhibitory peptides revealed that the alpha 4 beta 1-mediated adhesion was not influenced by peptides containing the RGD sequence. Attachment to the 70-kDa fragment was strongly inhibited by the CS-1 peptide, which represents the most active recognition domain for alpha 4 beta 1 integrin in fibronectin. The present data provide evidence that TSP-1 contains an alpha 4 beta 1 integrin-binding site within the 70-kDa core region.
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PMID:Adhesion of osteosarcoma cells to the 70-kDa core region of thrombospondin-1 is mediated by the alpha 4 beta 1 integrin. 1205 67

The Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) is a hematopoietic growth factor that regulates the in vitro and in vivo proliferation and differentiation of hematopoietic cells through the interaction with a specific heterodimeric receptor complex (GM-CSFR), consisting of an alpha and a beta chain with molecular weights of 80 and 120 KDa, respectively. We have studied the expression of the GM-CSFR (alpha chain) on the surface of the human osteosarcoma cell line SaOS-2 and the in vitro effects of different concentrations (10, 100, and 200 ng/ml) of GM-CSF on GM-CSFR expression and the biological activity of SaOS-2 cells. Our data show that SaOS-2 cells express GM-CSFR and that GM-CSF can down-regulate the expression of its own receptor on these cells. Furthermore, to evaluate the biological effects of GM-CSF on SaOS-2 cells, we have investigated cell proliferation and differentiation of these cells treated with different doses of the growth factor through: (1) a morphological analysis of typical osteoblast differentiation markers such as osteopontin and BSP-II; (2) measurement of alkaline phosphatase (ALP) activity; (3) production of bone ECM components (collagen I, fibronectin, tenascin, and laminin); (4) production of interleukin-6 (IL-6) and osteocalcin in the culture medium. The results show that the in vitro treatment of SaOS-2 cells with recombinant human GM-CSF causes a decreased cell proliferation and an increased production of osteopontin, BSP-II, ALP, IL-6, and most but not all ECM components. These findings suggest that GM-CSF can regulate proliferation and differentiation of osteoblast-like SaOS-2 cells and could also play an unexpected role in the maturation of bone tissue.
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PMID:Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces the osteoblastic differentiation of the human osteosarcoma cell line SaOS-2. 1223 77

The possibility that a sinusoidal 50 Hz magnetic field with a magnetic flux density of 0.5 mT can induce variations in the expression of cell adhesion molecules (CAMs) in two human osteosarcoma cell lines (MG-63 and Saos-2) was investigated. In particular, the expression of two important integrins, VLA-2, the receptor for collagen, and VLA-5, the receptor for fibronectin, as well as CD44, were examined in both cell lines after these had been exposed for 7 and 14 days to a 50 Hz, 0.5 mT field. Cell surface morphology (scanning electron microscopy), cell growth characteristics (growth curves and cell cycle phase distribution), and cell death (necrosis and apoptosis) were also examined. The results demonstrate that no variations in surface morphology and cell death occurred between control and exposed cells in both MG-63 and Saos-2 cells, while significant changes were noted in cell growth and fibronectin and CD44 expression in MG-63 cells. The results are discussed in view of the important role that CAMs play in controlling various cancer cell functions, particularly proliferation and metastasis.
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PMID:Effects of a 50 Hz sinusoidal magnetic field on cell adhesion molecule expression in two human osteosarcoma cell lines (MG-63 and Saos-2). 1282 Feb 90


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