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)

In previous studies we showed that human sarcoma and melanoma cell lines synthesize and secrete into culture medium a glycoprotein, migrating in urea sodium dodecyl sulfate-polyacrylamide gel electrophoresis at Mr 140,000. It is not detected in cultures of the corresponding normal cells. Conditioned medium of the melanoma cell line HMB-2, producing among the cell lines tested the largest amounts of this glycoprotein, has now been used as a source for purification of the protein. NH2-terminal amino-acid sequence determination of the purified glycoprotein showed that it is identical to human alpha 2-macroglobulin (alpha 2M). Rabbit antibodies raised against the glycoprotein specifically reacted in immunoblotting and immunodiffusion tests with alpha 2M present in human plasma. Likewise, these antibodies immunoprecipitated from the conditioned media of 35S-methionine-labelled melanoma and osteosarcoma cell lines the protein which had a molecular weight corresponding to alpha 2M. alpha 2M was also synthesized and secreted by 2 strains of fetal lung fibroblasts but not by fetal skin fibroblasts or adult skin fibroblasts autologous to the osteosarcoma cell line.
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PMID:Human tumor cells synthesize and secrete alpha-2-macroglobulin in vitro. 241

Methotrexate reduces intracellular pools of 5-methyltetrahydrofolate and could result in reduced conversion of homocysteine to methionine by methionine synthetase. This study was designed to investigate the effects of moderate dose to very high dose methotrexate on methionine and total homocysteine as reflections of methotrexate induced intracellular events. Methionine and total homocysteine were measured prior to, during, and following twenty-six 24-h i.v. infusions of 33.6 g/m2 methotrexate (very high dose methotrexate) in 16 children with acute lymphocytic leukemia and seven 4-h i.v. infusions of 8 g/m2 methotrexate (high dose methotrexate) in 5 children with osteogenic sarcoma. Amino acids were measured by gas chromatography/mass spectrophotometry. Mean methionine levels decreased by 70.0 +/- 3.1% (SE) with very high dose methotrexate and 72.6 +/- 5.9% with high dose methotrexate at 24 and 4.5 h, respectively, after beginning methotrexate infusions. Mean total homocysteine levels increased by 61.7 +/- 3.1% with very high dose methotrexate and 55.6 +/- 17.5% with high dose methotrexate at 36 and 24 h, respectively, after beginning methotrexate infusions. No consistent or significant changes were noted in levels of total cysteine, leucine, isoleucine, or valine. Similar changes did not occur in patients receiving prednisone, vincristine, daunomycin, and intrathecal methotrexate as therapy for acute lymphocytic leukemia. These changes in homocysteine and methionine may reflect biological effects of methotrexate that may predict cytotoxicity of methotrexate.
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PMID:Changes in plasma methionine and total homocysteine levels in patients receiving methotrexate infusions. 279 Aug 1

In order to know the true biodistribution of anti-tumor monoclonal antibodies, three monoclonal antibodies (OST6, OST7, and OST15) against human osteosarcoma and control antibody were internally labeled with 75Se by incubating [75Se]methionine and hybridoma cells. 75Se-labeled monoclonal antibodies were evaluated both in vitro and in vivo using the human osteogenic sarcoma cell line KT005, and the results were compared with those of 125I- and 111In-labeled antibodies. 75Se-, 125I- and 111In-labeled monoclonal antibodies had identical binding activities to KT005 cells, and the immunoreactivity was in the decreasing order of OST6, OST7, and OST15. On the contrary, in vivo tumor uptake (% injected dose/g) of 75Se- and 125I-labeled antibodies assessed using nude mice bearing human osteosarcoma KT005 was in the order of OST7, OST6, and OST15. In the case of 111In, the order was OST6, OST7, and OST15. High liver uptake was similarly seen with 75Se- and 111In-labeled antibodies, whereas 125I-labeled antibodies showed the lowest tumor and liver uptake. These data indicate that tumor targeting of antibody conjugates are not always predictable from cell binding studies due to the difference of blood clearance of labeled antibodies. Furthermore, biodistribution of both 111In- and 125I-labeled antibodies are not identical with internally labeled antibody. Admitting that internally labeled antibody is a "gold standard" of biodistribution of monoclonal antibody, high liver uptake of 111In-radiolabeled antibodies may be inherent to antibodies. Little, if any, increase in tumor-to-normal tissue ratios of antibody conjugates will be expected compared to those of 111In-labeled antibodies if stably coupled conjugates are administered i.v.
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PMID:Pharmacokinetics of internally labeled monoclonal antibodies as a gold standard: comparison of biodistribution of 75Se-, 111In-, and 125I-labeled monoclonal antibodies in osteogenic sarcoma xenografts in nude mice. 292 18

We have investigated the covalent modification of the proteins encoded by the murine fos proto-oncogene (c-fos) and that of the corresponding gene product of FBJ murine osteosarcoma virus (v-fos). Both proteins are posttranslationally processed in the cell, resulting in forms with lower electrophoretic mobilities than that of the initial translation product on sodium dodecyl sulfate-polyacrylamide gels. Treatment with alkaline phosphatase indicates that most, if not all, of this electrophoretic shift is due to phosphoesterification of both proteins. These phosphoryl groups stoichiometrically modify the v-fos and c-fos proteins on serine residues and turn over rapidly in vivo in the presence of protein kinase inhibitors (half-life, less than 15 min). Direct quantitative comparison of steady-state labeling studies with L-[35S]methionine and [32P]phosphate reveals that the c-fos protein is four- to fivefold more highly phosphorylated than the v-fos protein is. Comparison of tryptic fragments from [32P]phosphate-labeled proteins indicates that although the two proteins have several tryptic phosphopeptides in common, the c-fos protein contains unique major tryptic phosphopeptides that the v-fos protein lacks. These unique sites of c-fos phosphorylation have been tentatively localized to the carboxy-terminal 20 amino acid residues of the protein. Phosphorylation of the c-fos protein, but not the v-fos protein, can be stimulated at least fivefold in vivo by the addition of either 12-tetradecanoyl-phorbol-13-acetate or serum. This increase in the steady-state degree of phosphorylation of c-fos appears to be independent of protein kinase C since phosphorylation is Ca2+ and diacylglycerol independent. The possible role of phosphorylation of these proteins in cellular transformation is discussed.
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PMID:Modification of fos proteins: phosphorylation of c-fos, but not v-fos, is stimulated by 12-tetradecanoyl-phorbol-13-acetate and serum. 311 Jun 3

Retinoic acid (RA) and methionine were studied for their relative effectiveness in enhancing the ability of interferons (IFNs) to reverse the phenotype of murine methylcholanthrene (MCA)-transformed cells and human osteosarcoma (OHA) cells. Treatment with RA (1 microM) and methionine (25mM) alone had minimal or no effect on the proliferation of MCA and OHA cells or on the ability to form tumors in animals. Combination of these two agents with IFNs however, potentiated the inhibitory effects of IFNs on proliferation and colony formation of MCA transformed cells but not on their tumorigenicity. Similarly in human tumor OHA cells, only the combination of IFN and RA was more effective than IFN alone on proliferation and colony formation but not on tumorigenicity. Thus, the enhanced effects of combined treatments on cell proliferation in vitro could be distinguished from the inhibitory effects of IFNs on tumorigenicity in both murine transformed cells and human tumor cells.
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PMID:Retinoic acid or methionine enhance interferon's inhibition of the transformed phenotype with no effect on tumorigenicity. 317 23

We have previously shown that some transformed derivatives of the human osteosarcoma-derived cell line HOS are killed by treatment with 1 microM ouabain at pH 8.2, whereas their nontransformed counterparts are relatively unharmed by the same conditions. HOS cells transformed by v-Ki-ras and RAS, v-fms, or MET are susceptible to 1 microM ouabain while those transformed by v-fes are not. Here we describe the adaptation of this differentially cytotoxic effect as a method to enrich for cells which revert to a nontransformed phenotype. We have optimized parameters which increase the differential cytotoxicity, including pH and potassium concentration during and subsequent to ouabain treatment. The efficiency of this procedure was tested in mixed cell experiments where model populations were constructed consisting of HOS cells mixed with an excess of v-Ki-ras-transformed HOS cells. Two successive OAK treatments (ouabain/alkaline/K+-free) were sufficient to recover nontransformed cells free of ras-transformants as indicated by genetic markers and morphology. This HOS/ouabain system is currently being used to derive revertants of ras-transformed human cells and could facilitate the isolation of genes interacting in the pathways by which these cells are transformed.
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PMID:A system for deriving revertants of oncogene-transformed human cells. 319 49

The molecular nature of an osteosarcoma-associated antigen was investigated with the three monoclonal antibodies Ost6 (immunoglobulin (IgG1), Ost7 (IgG1), and Ost15 (IgG2a), which selectively react with frozen sections of osteosarcoma and chondrosarcoma tissues. When tested with a panel of 41 human cell lines in the mixed hemadsorption assay, the antibodies reacted similarly with three of six osteosarcomas, one choriocarcinoma, one teratoma, and one osteoblast-like culture, but failed to react with 32 lines of normal and other tumor cell types. Immunoprecipitation plus sodium dodecyl sulfate (SDS)--polyacrylamide gel electrophoresis and sequential immunoprecipitation studies revealed that in [35S]methionine- or [14C]glucosamine-labelled osteosarcoma cells the three antibodies detected a single glycoprotein, with an apparent molecular mass of 86 kilodaltons (kDa), which was not affected by reducing conditions. Tunicamycin treatment and pulse-chase experiments showed glycosylation of this molecule to be N-linked; it arose from a 54-kDa polypeptide precursor. Alkaline phosphatase activity was detected in the material rich in 86-kDa molecules that was immunoprecipitated from serologically reactive cell lines with each antibody. These antibodies also cross-reacted with two isoenzymes of alkaline phosphatase (strongly with the liver and bone, and moderately with the placental isoenzyme), but not with the intestinal form.
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PMID:Identification of a human osteosarcoma-associated glycoprotein with monoclonal antibodies: relationship with alkaline phosphatase. 333 Dec 86

Prolonged exposure of a nontumorigenic human osteogenic sarcoma cell line (HOS) with the direct acting carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) gave rise to morphologically transformed cells which were tumorigenic in nude mice and termed MNNG-HOS. We have shown that DNA from MNNG-HOS cells will transform NIH/3T3 cells and have isolated greater than 35 kb of human DNA containing an oncogene, termed met. The activated met oncogene expresses a novel 5.0 kb RNA transcript which is a hybrid RNA derived from a DNA rearrangement involving two distinct genetic loci termed met and tpr (translocated promoter region). The met proto-oncogene has been localized to 7q21-q31 by in situ hybridization. This locus expresses a 9.0 kb RNA in fibroblast and epithelial cell lines, but is not commonly expressed in cell lines derived from the hematopoietic cell lineage. In contrast, the tpr locus is on chromosome 1, and expresses a 10.0 kb RNA in all human cell lines tested. The novel 5.0 kb met oncogene RNA is 3' co-terminal with the 9.0 kb met proto-oncogene RNA, while the 5' portion of this RNA uses at least two exons derived from the 10.0 kb tpr RNA. These exons are small and are presumably in the promoter region of both tpr and tpr-met transcripts. Nucleotide sequence analysis of the 3' end of met shows that it is a member of the tyrosine kinase family of genes. Peptide antibody to the C-terminal coding region of met immunoprecipitates a 65 kilodalton (kd) polypeptide (p65) in both MNNG-HOS cells and met transformed NIH/3T3 cells. This product also has tyrosine kinase activity in vitro and is presumed to correspond to the tpr-met product. The same antibody detects three larger met-related polypeptides of 160, 140, and 110 kd in human fibroblasts and epithelial cells by in vivo labeling with [35S]methionine. However, only one of the three met proto-oncogene polypeptides, p140, appears to be phosphorylated in the in vitro kinase assay. High levels of in vitro 32P incorporation into p140 met are observed in 4 out of 30 human epithelial cancer cell lines tested. Activation of the met oncogene in MNNG-HOS cells results from a DNA rearrangement possibly mediated in vitro by MNNG. The mode of activation of met may therefore be similar to the epidermal growth factor (EGF)R/v-erbB oncogene; or the bcr/c-abl rearrangement present in the Philadelphia chromosome translocation which is found in chronic myelogenous leukemias.
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PMID:The human met oncogene is a member of the tyrosine kinase family. 333 11

Phorbol 12-myristate 13-acetate (PMA) induces time-dependent changes in protein kinase C subcellular distribution and enzymatic activity in the human osteosarcoma cell line SaOS-2. Short (less than 60 min) incubations with PMA caused decreased cytosolic enzyme activity and a concomitant increase in particulate protein kinase; after 3 h, particulate protein kinase C activity also declined to reach less than 10% of basal activity by 24 h (Krug, E., and Tashjian, Jr., A. H., (1987) Cancer Res. 47, 2243-2246). In order to determine whether the loss in enzyme activity was due to decreased enzyme protein, Western blot analyses were performed using a polyclonal antibody against protein kinase C raised in rabbits. This approach confirmed the previously reported time-related changes: 80-kDa immunoreactive protein kinase C initially translocated from the cytosol to the particulate cell fraction and later disappeared completely from the particulate fraction. Loss of protein kinase C enzymatic activity thus results from actual loss of the 80-kDa protein; we found no evidence for generation of a calcium/phospholipid-independent protein kinase C-like form of the enzyme. Membrane association was confirmed by immunoprecipitation experiments using [35S]methionine-labeled cells. Brief exposure to PMA caused a marked loss in the [35S]methionine-labeled cytosolic protein kinase C band and an increase in the labeled particulate band. Protein kinase C immunoprecipitated from cells treated with PMA for 14 h displayed an increase in [35S]methionine label despite a greater than 80% loss of enzyme activity. The high specific radioactivity of the remaining 80-kDa protein leads us to conclude that long term treatment with PMA causes an increase in the rate of protein kinase C synthesis accompanied by a still greater increase in the rate of enzyme degradation in SaOS-2 cells.
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PMID:Evidence for increased synthesis as well as increased degradation of protein kinase C after treatment of human osteosarcoma cells with phorbol ester. 347 87

We investigated the effects of 1,25-dihydroxyvitamin D3 on the synthesis of osteopontin, a phosphorylated cell attachment glycoprotein, in ROS 17/2.8 cells, a clonal osteoblast-like rat osteosarcoma cell line. We observed a dose dependent increase in uptake of [32PO4] into osteopontin secreted into the medium. An increased incorporation of [35S]-methionine into secreted osteopontin suggested the effect was that of increased protein biosynthesis. Using a radioimmunoassay we demonstrated a dose dependent increase in the amount of secreted osteopontin, an increase which could be blocked by Actinomycin D, in response to 1,25-dihydroxyvitamin D3. These results suggest that the hormonal form of vitamin D regulates the biosynthesis of osteopontin, possibly at the level of transcription.
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PMID:1,25-Dihydroxyvitamin D3 regulates the biosynthesis of osteopontin, a bone-derived cell attachment protein, in clonal osteoblast-like osteosarcoma cells. 347 71


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