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

Previous studies demonstrated that tetracyclines (TCs) inhibited Type I (interstitial) and Type IV collagenases from different mammalian sources, but there are no studies of TCs effect on osteoblast collagenase (C'ase). The present study assessed the effect of TCs on C'ase activity from osteosarcoma cells. Semiconfluent UMR 106-01 cells were treated with minocycline or chemically modified tetracycline (CMT) at 10 micrograms/ml in the presence or absence of bovine parathyroid hormone, b-PTH-(1-34), at 10(-7)M for 24, 48, 72 and 96 hours. Media were collected at each time point and assayed following concentration, destruction of TIMP by reduction/alkylation, activation with p-aminophenylmercuric acetate (APMA), and incubation with 3H-methylated collagen substrate (approximately 100,000 dpm) at 27 degrees C for 18 hours. Collagenase activity from media was also analyzed by SDS-PAGE and fluorography. b-PTH appeared to stimulate C'ase 60-fold compared to controls; minocycline and CMT reduced PTH stimulation approximately 65% and 90%, respectively. Moreover, TCs incubated with partially purified osteoblastic collagenase directly, inhibited its activity in vitro as indicated by a lack of degradation to collagen alpha A chains. Therefore, TCs ability to inhibit bone resorption in organ culture, reported previously, may be due, in part, to reduced osteoblast collagenase activity.
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PMID:The effect of tetracyclines on collagenase activity in UMR 106-01 rat osteoblastic osteosarcoma cells. 196 17

Secreted phosphoprotein I (SPPI; osteopontin), a highly phosphorylated form of which has been associated with cell transformation, is one of the major phosphorylated proteins in bone. Populations of rat bone cells derived from fetal calvariae, neonatal parietal bone and a rat osteosarcoma cell line (ROS 17/2.8) produce several forms of the protein, the major forms having apparent molecular masses of 55 and 44 kDa by SDS/PAGE on 15% (w/v) cross-linked gels and of 60 and 56 kDa on 10% gels. Northern blot analysis of SPPI mRNA using total cellular RNA revealed a single 1.5 kb mRNA species, indicating that the nascent protein chains of these phosphoproteins are identical. On treatment of the cells with transforming growth factor-beta (TGF-beta; 1 ng/ml), the levels of SPPI mRNA and the synthesis of the 55 kDa phosphoprotein, but not of the 44 kDa phosphoprotein, were increased by 1.8-4.5-fold in the normal osteoblastic cells, the stimulation first being evident at 3 h and reaching a maximum at 12 h. In the transformed ROS 17/2.8 cells, TGF-beta did not alter significantly the SPPI mRNA level or the synthesis of either the 55 kDa or the 44 kDa SPPI over the 24 h period studied. By comparison, neither the steady-state levels of SPARC (secreted protein, acidic, rich in cysteine) mRNA nor the synthesis of SPARC protein were affected significantly by the addition of TGF-beta to any of the osteoblastic bone cells. The half-lives for SPPI and SPARC mRNAs in the osteoblastic calvarial cells were calculated to be 18 h and greater than 50 h respectively, in both the presence and the absence of TGF-beta. Since the stability of the mRNA was unchanged by TGF-beta and the increased expression of SPPI mRNA could be blocked by cycloheximide, TGF-beta appears to increase transcription of the SppI gene indirectly by stimulating the synthesis of a protein that promotes transcription. These results demonstrate that several forms of SPPI are synthesized constitutively by bone cells, and that there are clear differences in the regulation of SppI gene expression by TGF-beta in normal bone cells compared with the tumorigenic ROS 17/2.8 cells. The differential responses of normal osteoblastic cells to TGF-beta in the expression of SPPI and the selective stimulation of specific forms of the SPPI protein may be important in bone repair and remodelling.
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PMID:Regulation of transformation-sensitive secreted phosphoprotein (SPPI/osteopontin) expression by transforming growth factor-beta. Comparisons with expression of SPARC (secreted acidic cysteine-rich protein). 199 53

It has long been thought that the process of bone remodeling is regulated by the chain reactions of bone cells involving chemical mediators, growth factors and synthesis of extracellular matrix proteins etc. In this context, it has also been recognized that physical stimulation is an important factor in the regulation of bone remodeling. Thus, it is vitally important to understand whether the physical stimulation can induce the cellular events regarding autocrine regulation of protein synthesis. This study was conducted to examine the effects of hydrostatic intermittent compressive force (ICF) on the synthesis of the transforming growth factor beta (TGF-beta) and matrix phosphoproteins which may play an important role in the process of bone remodeling. The rat osteosarcoma cells (ROS 17/2.8) were cultured with DMEM containing 10% FCSP. ICF was applied to sub-confluent cells at 130 mb, 15/min cycle for 48h. ICF increased TGF-beta activity of the conditioned medium. This was assessed by its capacity to promote anchorage independent growth of NRK 49F cells and to inhibit the growth of human hepatoma cells (Hep-3B). Furthermore, ICF stimulated the synthesis of the phosphoproteins with Mr. 75 KDa by about 1.4 fold which was visualized by SDS-PAGE on 5-15% gradient gel. Immunoprecipitation of the phosphoproteins with rat osteopontin antibody revealed that the 75 KDa phosphoprotein was identical to osteopontin. The 75 KDa osteopontin synthesis was inhibited by the addition of TGF-beta antibody in a dose dependent manner. These results suggested that ICF stimulated the synthesis of TGF-beta and osteopontin in ROS 17/2.8 cells and that the osteopontin synthesis could be regulated by TGF-beta.
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PMID:[Effects of intermittent compressive force on transforming growth factor beta and osteopontin synthesis in cultured bone cells]. 213 41

The murine retrovirus shuttle vector pZipNeo SV(X)1 was used to construct plasmids encoding the three major surface glycoproteins of bovine herpesvirus-1 (BHV-1). Each plasmid was transfected into D17, a canine osteosarcoma cell line sensitive to lysis by bovine NK-like cells when infected with BHV-1. After selection in G418 sulfate, cell lines expressing the recombinant gene products were sorted by flow microfluorimetry, radioimmunoprecipitated, and analyzed by SDS-PAGE for fidelity as compared to the native viral glycoproteins. Two of the three genetically engineered cell lines (gI and gIV) could successfully serve as targets to detect bovine NK-like cytolysis. These findings support and extend a previous study from our laboratory indicating a role for BHV-1 glycoproteins in the cytolytic response by bovine NK-like cells. Additionally, this study demonstrated that individual proteins are recognized by these effector cells, and that recombinant glycoproteins can direct cytolytic activity in the absence of host cell infection-associated proteins. This is the first known report of Ag directed cytotoxicity by bovine null (non-B, non-T) cells.
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PMID:Bovine natural killer-like cell responses against cell lines expressing recombinant bovine herpesvirus type 1 glycoproteins. 216 95

Immunoprecipitation and Western immunoblotting studies were undertaken using purified high-affinity antibodies against a synthetic peptide corresponding to a portion of the deduced retinoblastoma (RB) protein. On SDS-PAGE, normal human cells showed an RB protein pattern consisting of a lower sharp band with a Mr of 110 kD and a more variable region above this band with a Mr ranging from 110 kD to 116 kD. The 110 kD band represents the unphosphorylated Rb protein whereas the broader, less well defined region is the phosphorylated RB protein in which molecular mass heterogenicity results from varying amount of phosphorylation. This pattern repeats once at a lower Mr in which a 98 kD band and 98-104 kD variable region can be visualized. This latter conformation seems to represent the unphosphorylated and phosphorylated RB protein translated from the second AUG codon of the RB mRNA. Cellular RB mRNA extracted from normal fibroblasts was translated in vitro reinforcing the usage of this second start codon. A higher ratio of phosphorylated to unphosphorylated Rb protein was seen in cells growing in log phase compared to those arrested in G1 phase. Our present studies also detected two candidates for RB-associated cellular proteins with a Mr of 124 kD and 55 kD respectively. In addition, shortened versions of RB-isoantigenic proteins were found in retinoblastoma and osteosarcoma cell lines.
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PMID:The retinoblastoma susceptibility gene product: a characteristic pattern in normal cells and abnormal expression in malignant cells. 247 53

The c-fos gene, the cellular homologue of the transforming gene of the FBJ osteosarcoma virus, v-fos, is strongly induced in quiescent BALB/c 3T3 cells by growth factors and in other cell types by a wide variety of transmembrane signalling agents. c-fos is a member of a family of structurally related proteins which includes the fos-related antigens (fra). We have studied the dynamic state of the c-fos protein with an antibody prepared by immunizing rabbits with a plasmid-encoded fos fusion protein. In serum-stimulated BALB/c 3T3 cells, the antibody recognizes a nuclear antigen which resolves on SDS-PAGE as a 60-68-kD group of bands corresponding to c-fos, a doublet at 44-45-kD corresponding to the noncovalently associated p39 protein, as well as an approximately 50-kD band corresponding to a fra. We show that although c-fos protein synthesis is only transiently induced by serum, the c-fos protein persists within the cell after its synthesis has ceased, and it decays with a half-life of 2 hours. Significantly, newly synthesized p39 continues to appear in the immune-precipitated complex even at times when c-fos is no longer synthesized. These kinetics indicate that even following shutoff of c-fos protein synthesis, p39 is newly synthesized and can complex with c-fos protein or a fos-related antigen. During this time, c-fos also undergoes an extensive posttranslational modification. The modification is partially reversed by phosphatase treatment, which implicates protein phosphorylation. Together these results suggest that both interaction with p39 and phosphorylation may progressively modify the properties of c-fos and/or the fos-related antigens over a period of 4-8 hours following the shutoff of fos synthesis. We discuss the implications of the dynamic state of c-fos and fra protein interactions for the function of these proteins.
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PMID:Dynamic interactions of c-fos protein in serum-stimulated 3T3 cells. 249 95

We investigated a new chemosensitivity test, MTT-hybrid assay, which was a hybrid of MTT colorimetric assay and double-layered soft agar colony assay, using human bone and soft tissue tumor cells. MTT formazan crystals produced by viable cells in the soft agar medium were solubilized by SDS at 60 degrees C. The absorbance (560 nm) is directly proportional to the cell number over a wide range. The absorbance increased in proportion to colonial growth of osteosarcoma cells, while it decreased in a human diploid cell strain in a few days. Drug sensitivity of tumor cells is supposed to be assessed without contaminating normal cells by MTT-hybrid assay in primary tumor samples. Good correlation of IC50 was observed between MTT-hybrid assay and colony assay. The MTT-hybrid assay shows potential value as a rapid predictive test for chemotherapeutic agents in an individual patient.
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PMID:[A study of MTT-hybrid assay using human bone and soft tissue tumor cells]. 251 17

The secretion of elevated levels of proteinases is considered to be a distinct property of most transformed cells. The cellular and secreted levels of plasminogen activators and collagenases have been examined in the nonmalignant human osteosarcoma (HOS), the malignant Kirsten murine sarcoma virus transformed (KHOS/NP), the temperature sensitive revertant of virus transformed HOS (KHOS-240S) and N-methyl-N'-nitro-N-nitrosoguanidine transformed HOS (MNNG/HOS) clones. Virus and MNNG transformed clones exhibit 100- and 7-fold higher cellular and and 270- and 30-fold higher extracellular plasminogen activator (PA) activity as compared with untransformed HOS controls. The cellular PA activity of the revertant clone is similar to but the secreted level is slightly higher than the HOS controls. SDS-PAGE in the presence of casein and plasminogen is consistent with the major PA species of urinary type (u-PA) and with the absence of PA inhibitor in the parent and revertant clones. The cellular levels of active collagenase are low in all the clones. However, on activation by trypsin, the two active collagenase bands of similar intensity are observed for all the lines in SDS-PAGE in the presence of gelatin. While there appears to be some elevation of secreted collagenase prior to trypsin activation, the activated collagenases appear to have the same size and activity in all of the clones.
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PMID:Synthesis and secretion of plasminogen activators and collagenases in human cells transformed by Kirsten murine sarcoma virus and N-methyl-N'-nitro-N-nitrosoguanidine. 256 62

Endosomal preparations from human osteosarcoma cells and from fibroblasts contain 51,000- and 26,000-Mr proteins which bind a small dermatan sulphate proteoglycan after SDS/polyacrylamide-gel electrophoresis and Western blotting. Binding can be inhibited by unlabelled proteoglycan core protein. The proteins co-precipitate with a proteoglycan core protein-antibody complex. Scatchard analysis of immobilized endosomal proteins yielded a KD of about 37 nM for the proteoglycan. In intact cells proteins of the same size can be found. They are sensitive to trypsinization. A 51,000-Mr protein is the predominant membrane protein with strong binding to immobilized dermatan sulphate proteoglycan. There are additional proteoglycan-binding proteins with Mr values of around 30,000 and 14,000 which are insensitive to trypsin treatment. In contrast with the 51,000- and 26,000-Mr proteins, they resist deoxycholate/Triton X-100 extraction several days after subcultivation.
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PMID:Endocytosis of a small dermatan sulphate proteoglycan. Identification of binding proteins. 260 92

In this study we have shown by both immunofluorescence and immunoprecipitation techniques that human osteoblasts and osteosarcoma cells synthesize and secrete thrombospondin, a 450-kDa glycoprotein initially found in platelets. Immunofluorescence with a mouse monoclonal antibody to human platelet thrombospondin yielded specific granular staining within the cytoplasm of human osteoblasts. SDS/polyacrylamide gel electrophoresis analysis of immunoprecipitates obtained with polyclonal and monoclonal anti-thrombospondin antibodies allows the identification of thrombospondin in the cellular lysates and the culture media of biosynthetically labelled osteoblasts and osteosarcoma cells. Kinetic and dose/response studies of osteoblasts and of two osteosarcoma cell lines (MG-63, SaOs-2) were performed to assess the ability of these cells to adhere to thrombospondin and type-I collagen. Thrombospondin promoted the attachment of human osteoblasts whereas it inhibited the adhesion of MG-63 and SaOs-2 cells, both when it was directly adsorbed to plastic and when it was bound to type-I collagen. Therefore osteoblasts and osteosarcoma cells may be valuable tools to study the role of thrombospondin in cell adhesion.
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PMID:Thrombospondin is synthesized and secreted by human osteoblasts and osteosarcoma cells. A model to study the different effects of thrombospondin in cell adhesion. 265 48


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