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)

We have previously reported that vasoactive intestinal peptide (VIP) stimulates bone resorption in organ culture via a cAMP-dependent mechanism. Here we describe functional receptors for VIP on a clonal line of human osteosarcoma cells, SaOs-2. SaOs-2 cells respond to VIP with an increase in cAMP. The effect was rapid (2 min) and dose dependent from 0.15-15 nM VIP, with half-maximal stimulation at 1.4 nM. SaOs-2 cells produce prostaglandin E2 (PGE2) and respond to exogenous PGE2 with increases in cAMP approximately one third as great as those induced by VIP. However, the VIP-stimulated increases in cAMP occurred without detectable increases in PGE2 production, and increases in cAMP were unaffected by the cyclooxygenase inhibitor indomethacin. SaOs-2 cells pretreated with VIP for 24 h were significantly less responsive to a second acute challenge with VIP, but retained their ability to respond to PGE2. Similarly, pretreatment with PGE2 induced homologous desensitization to PGE2, but had no effect on the VIP-stimulated increase in cAMP. These patterns of response paralleled those previously described in whole bone in organ culture. Binding studies with [125I]VIP demonstrated specific, saturable, high affinity receptors for VIP on SaOs-2 cells. Scatchard analysis of [125I]VIP binding at 37 C resulted in a curvilinear plot. Analysis based upon the assumption of two independent binding sites gave Kd values of 0.44 and 17 nM for high and low affinity binding sites, respectively. The numbers of high and low affinity sites per cell were determined to be 8,500 and 57,000, respectively. Binding of [125I]VIP was partially inhibited by two related peptides, secretin and PHI-27, but not by PTH, calcitonin or a variety of unrelated peptides. We conclude that the action of VIP on human SaOs-2 cells is similar to that observed in intact mouse calvaria, and that these cells provide a good model for the study of the initial steps of VIP action in bone.
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PMID:Functional receptors for vasoactive intestinal peptide on human osteosarcoma cells. 632 42

Preincubation of Dunn osteosarcoma cells for 1 h with both 100 nM of staurosporine and 10 micrograms/ml of genistein resulted in a significant decrease in the motility stimulated by autocrine motility factor (AMF), whereas these reagents did not affect the basal motility and proliferation at these concentrations. The effect of the agents on the stimulated motility was both dose- and time-dependent. The motility stimulated by the anti-AMF receptor mAb was also inhibited. In contrast, H-8 had a negligible effect upon the stimulated motility. These data suggest that both kinase C and tyrosine kinase play a role in AMF-stimulated cell motility, while protein kinase A, which is selectively associated with the adenylate cyclase pathway, may not be required for the stimulation.
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PMID:Effects of protein kinase inhibitors on the cell motility stimulated by autocrine motility factor. 803 8

Response to neoadjuvant chemotherapy is a significant prognostic factor for osteosarcoma (OS). 18-F-fluorodeoxy-D: -glucose (FDG) positron emission tomography (PET) is a noninvasive imaging modality that correlates with histological grading in musculoskeletal sarcomas. To determine the prognostic value of FDG PET in patients receiving chemotherapy, 13 patients were evaluated by FDG-PET, and followed for more than 4 years. FDG PET standardized uptake values before (SUV1) and after (SUV2) chemotherapy were analyzed and correlated with the expression of metastasis-related glycolytic enzyme, autocrine motility factor (AMF)/phosphoglucose isomerase (PGI) by immunohistochemical examination in surgically excised tumors. Although mean SUV1 for OS patients with metastatic lesions were similar to those in the completely disease-free (CDF) group (6.5 vs. 6.6, respectively, P = 0.975), mean SUV2 for OS with metastatic lesions were significantly higher than those in the CDF group (5.1 vs. 2.5, respectively, P = 0.0445). Interestingly, immunohistochemical analysis using anti-AMF/PGI antibody revealed that SUV2 correlated significantly with the AMF/PGI staining titers (P = 0.0303), while no correlation between SUV1 and the AMF/PGI staining titers existed (P = 0.964). The present study suggests that FDG PET after chemotherapy may provide information for AMF/PGI-related metastatic potentiality of residual tumors located out side of the area surgically resected afterward, and then lead to a useful prediction of the patients' prognosis.
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PMID:Prognostic significance of 18F-FDG uptake in primary osteosarcoma after but not before chemotherapy: a possible association with autocrine motility factor/phosphoglucose isomerase expression. 1830 93

We undertook a study of the anti-tumour effects of hyperthermia, delivered via magnetite cationic liposomes (MCLs), on local tumours and lung metastases in a mouse model of osteosarcoma. MCLs were injected into subcutaneous osteosarcomas (LM8) and subjected to an alternating magnetic field which induced a heating effect in MCLs. A control group of mice with tumours received MCLs but were not exposed to an AMF. A further group of mice with tumours were exposed to an AMF but had not been treated with MCLs. The distribution of MCLs and local and lung metastases was evaluated histologically. The weight and volume of local tumours and the number of lung metastases were determined. Expression of heat shock protein 70 was evaluated immunohistologically. Hyperthermia using MCLs effectively heated the targeted tumour to 45 degrees C. The mean weight of the local tumour was significantly suppressed in the hyperthermia group (p = 0.013). The mice subjected to hyperthermia had significantly fewer lung metastases than the control mice (p = 0.005). Heat shock protein 70 was expressed in tumours treated with hyperthermia, but was not found in those tumours not exposed to hyperthermia. The results demonstrate a significant effect of hyperthermia on local tumours and reduces their potential to metastasise to the lung.
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PMID:Targeted hyperthermia using magnetite cationic liposomes and an alternating magnetic field in a mouse osteosarcoma model. 2035 39

Phosphoglucose isomerase (PGI) is a multifunctional enzyme that functions in glucose metabolism as a glycolytic enzyme catalyzing an interconversion between glucose and fructose inside the cell, while it acts as cytokine outside the cell, with properties that include autocrine motility factor (AMF)-regulating tumor cell motility. Overexpression of AMF/PGI induces epithelial-to-mesenchymal transition with enhanced malignancy. Recent studies have revealed that silencing of AMF/PGI resulted in mesenchymal-to-epithelial transition (MET) of human lung fibrosarcoma cells and breast cancer cells with reduced malignancy. Here, we constructed a hammerhead ribozyme specific against GUC triplet at the position G390 in the human, mouse, and rat AMF/PGI mRNA sequence. Mesenchymal human osteosarcoma MG-63, HS-Os-1, and murine LM8 cells were stably transfected with the ribozyme specific for AMF/PGI. The stable transfectant cells showed effective downregulation of AMF/PGI expression and subsequent abrogation of AMF/PGI secretion, which resulted in morphologic change with reduced growth, motility, and invasion. Silencing of AMF/PGI induced MET, in which upregulation of E-cadherin and cytokeratins, as well as downregulation of vimentin, were noted. The MET guided by AMF/PGI gene silencing induced osteosarcoma MG-63 to terminally differentiate into mature osteoblasts. Furthermore, MET completely suppressed the tumor growth and pulmonary metastasis of LM8 cells in nude mice. Thus, acquisition of malignancy might be completed in part by upregulation of AMF/PGI, and waiver of malignancy might also be controlled by downregulation of AMF/PGI.
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PMID:Silencing of autocrine motility factor induces mesenchymal-to-epithelial transition and suppression of osteosarcoma pulmonary metastasis. 2097 90