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)

Human osteosarcoma cells secrete a novel C-X-C chemokine called granulocyte chemotactic protein-2 (GCP-2), which was previously identified by amino acid sequencing of the purified natural protein. In order to understand the role of this new protein in inflammatory reactions, we cloned GCP-2 DNA sequences to generate recombinant protein and specific DNA probes and primers. By means of PCR on cloned cDNA of osteosarcoma cells induced by interleukin-1 beta and fibroblasts induced by lipopolysaccharide plus dsRNA, the complete coding domain of GCP-2 was isolated. This sequence was cloned into the bacterial expression vector pHEN1 and, after induction, GCP-2 was secreted into the periplasm of Escherichia coli. Recombinant GCP-2 (rGCP-2) was purified and characterized by SDS/PAGE as a monomeric 6.5-kDa protein and by amino-terminal sequencing. The chemoattractive potency of GCP-2 for neutrophilic granulocytes was about 10-times less than that of interleukin-8 and the minimal effective dose was 10 ng/ml. However, at optimal dose (100 ng/ml) the maximal chemotactic response was comparable with that of interleukin-8. Both characteristics correspond with those of natural GCP-2. In addition, intracellular calcium release in neutrophils by recombinant GCP-2 was achieved with as little as 10 ng/ml. Quantitation studies using reverse transcriptase and the polymerase chain reaction revealed higher GCP-2 mRNA production in normal fibroblasts than in tumor cells. When compared with epithelial-cell-derived neutrophil-activating peptide-78 (ENA-78) mRNA, the GCP-2 mRNA levels were higher in all cell lines tested. In addition, GCP-2 and ENA-78 expression seem to be differentially regulated in that phorbol ester and lipopolysaccharide have opposing effects on their mRNA induction in diploid fibroblasts and epithelial cells, respectively. Interleukin-1 was demonstrated to be a general inducer for both chemokines, while interferon-gamma down-regulates their mRNA expression. The availability of recombinant GCP-2 together with the quantitation studies on mRNA expression will help to further elucidate the biological role of GCP-2 during the inflammatory response.
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PMID:Cloning, bacterial expression and biological characterization of recombinant human granulocyte chemotactic protein-2 and differential expression of granulocyte chemotactic protein-2 and epithelial cell-derived neutrophil activating peptide-78 mRNAs. 905 43

Nitric oxide (NO) is known to be implicated in the metabolism of bone, especially as a mediator of cytokine effects on the remodelling of bone tissue. In this study we examine whether NO affects the osteoblast activation or the osteoclast differentiation of primary mouse osteoblast-like and osteosarcoma ROS 17/2.8 cell lines. Primary osteoblast and ROS 17/2.8 cells released NO upon stimulation of interleukin-1 beta, tumour necrosis factor-alpha, and interferon-gamma. Sodium nitroprusside, a donor of nitric oxide, increased the activity of alkaline phosphatase in ROS 17/2.8 cells as well as the number of calcified nodule formations in primary mouse osteoblast-like cells. Sodium nitroprusside also completely inhibited 1 alpha, 25-(OH)2D3-induced osteoclast generation in a high concentration (100 microM). However, a low concentration of sodium nitroprusside (3-30 microM) significantly increased the generation of osteoclasts. These results indicated that NO appears to be an important regulatory molecule in the processes of bone formation and resorption. Hence, NO may be involved in the pathogenesis of bone loss in diseases associated with cytokine activation, such as periodontal disease and rheumatoid arthritis.
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PMID:Nitric oxide is a regulator of bone remodelling. 930 58

Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) has been implicated in the etiology of localized juvenile periodontitis (LJP), and produces a multiplicity of tissue-damaging products. Among those products, the capsular-like polysaccharide antigen (CPA) from A. actinomycetemcomitans is a potent mediator of bone resorption. In fact, this CPA (serotype b) is known to promote osteoclast-like cell formation via interleukin (IL)-1alpha production in mouse marrow cultures. Although osteoblasts complete bone formation, there are few reports focusing on the effect of CPA in bone-forming activity of osteoblasts in inflammatory disease sites. We hypothesized that CPA plays a mediating role in osteoblastic cells. Therefore, the purpose of this study was to examine the effect of CPA from A. actinomycetemcomitans on the mouse osteoblastic cell line MC3T3-E1 and human osteosarcoma SaOS-2 cells. A. actinomycetemcomitans serotype c resulted in a potent dose-dependent inhibition of cell proliferation of both cell lines. Characterization of the antiproliferative activity in the CPA demonstrated that it was not cytotoxic for MC3T3-E1. A 20-hour incubation with CPA-c resulted in a significant increase in apoptotic cell death in the cells, as evaluated by both cellular DNA fragmentation ELISA and FACS analysis. In contrast to the results obtained with a cytokine mixture (tumor necrosis factor-alpha, IL-1beta, and interferon-gamma), no inducible nitric oxide (NO) synthase gene expression or NO release could be detected in MC3T3-E1 after incubation with CPA-c. Further, both CPA-b and -c caused potent induction of apoptosis-related modifiers, e.g., Fas mRNA, whereas bcl-2 mRNA levels were unchanged. Therefore, this study has shown that CPA from A. actinomycetemcomitans contains a potent antiproliferative polysaccharide whose activity is associated with apoptotic cell death in MC3T3-E1, and that CPA per se is an inducer of apoptosis mediated by the Fas system but not by NO.
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PMID:Anti-proliferative capsular-like polysaccharide antigen from Actinobacillus actinomycetemcomitans induces apoptotic cell death in mouse osteoblastic MC3T3-E1 cells. 1037 Dec 46

The insulin-like growth factor-I receptor (IGF-l-R) plays a critical role in normal and pathological growth processes. The expression of the IGF-l-R gene is regulated by various stimuli, including hormones and growth factors. We have investigated the molecular mechanisms by which two inhibitory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), regulate IGF-l-R gene expression. TNF-alpha and IFN-gamma reduced the proliferation rates of the osteogenic sarcoma cell line, Saos-2, and the human salivary gland cell line, HSG, in a dose- and time-dependent fashion. This effect was associated with significant reductions in the levels of IGF-l-R mRNA and protein, and with inhibition of IGF-l-R promoter activity, suggesting that TNF-alpha and IFN-gamma affect IGF-l-R gene expression at the transcriptional level. In addition, TNF-alpha significantly decreased IGF-l-R mRNA stability. Combined cytokine treatment inhibited cellular proliferation and promoter activity in an additive manner. Taken together, these results suggest that a novel potential mechanism by which TNF-alpha and IFN-gamma affect cellular proliferation involves suppression of IGF-l-R promoter activity, as well as destabilization of IGF-l-R transcripts.
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PMID:Regulation of insulin-like growth factor-I receptor gene expression by tumor necrosis factor-alpha and interferon-gamma. 1136 37

We have previously reported that an osteosarcoma vaccine generated by ex vivo transfection of B7-1 cDNA induces protective as well as curative immunity against B7-1-negative parental osteosarcoma. Because establishment of human osteosarcoma cell lines, which is a prerequisite for ex vivo gene transfer, is rarely successful, we, in the present study, investigated the therapeutic efficacy of adenovirus-mediated in vivo B7-1 gene transfer to pre-established primary tumor as well as pulmonary metastasis of osteosarcoma. Adenovirus-mediated rat B7-1 gene transfer induced (a) expression of B7-1 molecules in osteosarcoma cells by both in vitro and in vivo infection procedures, (b) curative immunity against pre-established primary osteosarcoma and, subsequently, hosts gained protection against additional challenge of parental B7-1-negative osteosarcoma cells, (c) systemic immunity against pre-established pulmonary metastasis, and (d) activation of regional lymph node CD4(+) T cells, expansion of dendritic cells and natural killer cells and the secretion of interferon-gamma. These findings collectively support the therapeutic value of adenovirus-mediated in vivo gene transfer on osteosarcoma, which is of greater simplicity than cell-based B7-1 vaccine, and represent an attractive strategy for therapy of patients with metastatic osteosarcama who acquired resistance to current therapeutic protocols.
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PMID:Adenovirus-mediated in vivo B7-1 gene transfer induces anti-tumor immunity against pre-established primary tumor and pulmonary metastasis of rat osteosarcoma. 1218 24

Cytokines play important roles in the expression of adhesion molecules and the function of anti-tumor effector cells in the immune system. In this study, the influence of interleukin-12 (IL-12) and IL-18 on the expression of ICAM-1 and natural killer (NK)-cell mediated lysis in a human osteosarcoma cell line (HOS) was evaluated. ICAM-I expression of HOS cells were analyzed by flow cytometry following treatment with IL-12, IL-18 or both, and in co-cultures with peripheral lymphocytes. NK-cell activation in response to IL-12 and IL-18 was investigated by selective flow cytometry using propidium iodide. ICAM-1 expression on HOS cells was significantly enhanced by IL-12, but only when co-cultured in cell-to-cell contact with peripheral lymphocytes. Antibodies to interferon-gamma abrogated this effect. If HOS cells and peripheral lymphocytes were separated in co-cultures, IL-18 could substitute for cell-to-cell contact, facilitating IL-12-mediated enhancement of ICAM-1. Addition of IL-18 also enhanced NK-mediated cytolysis of HOS cells. These findings demonstrate that IL-12 can enhance the expression of ICAM-1 in the presence of IFN-gamma and, with IL-18, enhances NK anti-tumor activity. Immunomodulation via cytokine therapy may lead to improved eradication of chemotherapy-resistant osteosarcomas.
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PMID:Interleukin-12 and interleukin-18 change ICAM-I expression, and enhance natural killer cell mediated cytolysis of human osteosarcoma cells. 1466 53

The IGF-I receptor (IGF-IR) exhibits potent mitogenic, antiapoptotic, and transforming activities. Previous studies have suggested that the expression of the IGF-IR gene is negatively regulated by certain cytokines, including interferon-gamma (IFN-gamma). The potential involvement of STAT proteins in transcriptional regulation of the IGF-IR gene by IFN-gamma was addressed by transient coexpression of vectors encoding STAT1 and STAT5b, together with an IGF-IR promoter luciferase reporter, in the osteosarcoma-derived cell line Saos-2. Physical interactions between IFN-gamma-induced transcription factors and the IGF-IR promoter region were examined by electrophoretic mobility shift assays (EMSA). The results obtained indicate that the mechanism of action of IFN-gamma involves stimulation of STAT1 which, in turn, binds IFN-gamma activation sites (GAS) in the IGF-IR regulatory region, thus suppressing promoter activity. Taken together, our results suggest that the IGF-IR gene is a novel target for STAT1 action and that at least part of the inhibitory effects of STAT1 may involve repression of the strongly antiapoptotic IGF-IR gene.
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PMID:Signal transducer and activator of transcription-1 (STAT1), but not STAT5b, regulates IGF-I receptor gene expression in an osteosarcoma cell line. 1505 56

Her-2/neu is a tumor-associated antigen that has been targeted with both antibodies and cytotoxic T lymphocytes (CTL). Despite the isolation of Her-2/neu-reactive CTL in vaccinated patients, their therapeutic use has been limited by the observation that they often do not robustly recognize Her-2/neu(+) tumors. We sought to determine the mechanism for this escape using Ag201P and Ag201M cells, which are murine osteosarcoma tumor lines that express a functional HLA-A2/K(b) molecule. We now demonstrate that Ag201P and Ag201M express low levels of murine Her-2/neu, and that Ag201M was modestly and inconsistently recognized by an HLA-A2-restricted, Her-2/neu-reactive human CTL clone. In order to determine whether inefficient antigen processing might account for the weak recognition, COS-A2 cells were transfected with a short Her-2/neu minigene coding for the immunodominant Her-2/neu:369 epitope that did not require antigen processing or a long Her-2/neu minigene that did require antigen processing. Her-2/neu-reactive CTL clones only recognized COS-A2 cells transfected with the short minigene, indicating that lack of proper antigen processing could be responsible for the poor recognition of target cells. To confirm these results, it was demonstrated that following treatment with interferon-gamma, both Ag201P and Ag201M robustly and consistently stimulated the CTL clones. Furthermore, CTL clone recognition was enhanced following interferon-gamma treatment using another murine tumor line that expressed low levels of Her-2/neu (B16-A2/K(b)). The enhanced recognition of Ag201P and Ag201M in the presence of interferon-gamma was not due to an upregulation of Her-2/neu protein expression. Collectively, these results suggest that inefficient antigen processing of Her-2/neu can contribute to the lack of tumor recognition by CTL. These results also suggest that even tissues that express low levels of Her-2/neu might become CTL targets under conditions in which antigen processing is enhanced.
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PMID:Interferon-gamma renders tumors that express low levels of Her-2/neu sensitive to cytotoxic T cells. 1615 8

We evaluated the possible induction of a systemic immune response to increase anti-tumour activity by the re-implantation of destructive tumour tissue treated by liquid nitrogen in a murine osteosarcoma (LM8) model. The tumours were randomised to treatment by excision alone or by cryotreatment after excision. Tissue from the tumour was frozen in liquid nitrogen, thawed in distilled water and then re-implanted in the same animal. In addition, some mice received an immunological response modifier of OK-432 after treatment. We measured the levels of interferon-gamma and interleukin-12 cytokines and the cytotoxicity activity of splenocytes against murine LM8 osteosarcoma cells. The number of lung and the size of abdominal metastases were also measured. Re-implantation of tumour tissue after cryotreatment activated immune responses and inhibited metastatic tumour growth. OK-432 synergistically enhanced the anti-tumour effect. Our results suggest that the treatment of malignant bone tumours by reconstruction using autografts containing tumours which have been treated by liquid nitrogen may be of clinical value.
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PMID:Re-implantation of tumour tissue treated by cryotreatment with liquid nitrogen induces anti-tumour activity against murine osteosarcoma. 1875 69


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