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)

The role of urokinase plasminogen activator (uPA) in osteosarcoma is poorly understood. We examined the importance of uPA, its receptor, uPAR, and its inhibitor, PAI-1, in our in vivo model of metastatic osteosarcoma. Rodent osteosarcoma cells (UMR 106-01) were inoculated into the tibia of athymic mice. Animals were sacrificed and autopsied at 4 days to 5 weeks after inoculation. Tibiae and lungs were excised, fixed, and examined histologically and by in situ hybridization. Osteosarcoma development was associated with tibial swelling and lameness, and radiographic changes included osteolysis and new bone formation. Lung metastases developed spontaneously. In the tibial tumors, uPAR mRNA was expressed early (4 days), whereas uPA and PAI-1 mRNA increased as the tumor invaded the surrounding tissue (3 weeks). There was also an increase in the mRNA expression of the osteoblast-related genes, alpha1(I) procollagen and osteopontin, but not matrix Gla protein. Lung metastases also expressed mRNA for the uPA system and the bone-related proteins. We have produced a model of metastatic osteosarcoma, which typifies the characteristics of the human tumor. Our results suggest that the uPA system plays a role in the local aggressiveness and metastasis of osteosarcoma and, in particular, indicates a possible therapeutic role for uPAR antagonists in the treatment of osteosarcoma.
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PMID:The expression of the urokinase plasminogen activator system in metastatic murine osteosarcoma: an in vivo mouse model. 1141 May 3

To further characterize the role of hepatocyte growth factor-scatter factor (HGF-SF) and its receptor (c-Met) in osteosarcoma (OS), human OS cell lines with low (SAOS-2) and high (SAOS-LM2) metastatic potential, and cell lines derived from spontaneous canine OS were studied. All cell lines were evaluated for c-Met and HGF-SF expression and receptor activation using Northern, RT-PCR, and Western blot analyses, respectively. Functional activity of receptor-ligand interaction was measured using c-Met phosphorylation status, proliferation assays (anchorage-dependent and -independent), Matrigel invasion, modulation of urokinase plasminogen activator (uPA) expression, and cell dispersion (scattering). All cell lines exhibited steady-state mRNA expression of c-Met. The canine OS cell lines also expressed HGF-SF mRNA as determined by RT-PCR analysis. Western analysis showed c-Met protein expression and HGF-stimulated (human) or constitutive (canine) receptor autophosphorylation. Treatment with recombinant human HGF resulted in enhanced proliferation in 3 of 5 OS cell lines and enhanced colony formation in 2 of 5 OS cell lines. Matrigel invasion was significantly enhanced in 3 of the cell lines and uPA levels were significantly increased in the SAOS-2 cells following HGF treatment. Scattering was enhanced in both the SAOS-2 and SAOS-LM2 cells. These data support the involvement of c-Met and HGF-SF in the growth and progression of human and canine OS, and may offer new targets for the development of therapeutic strategies for OS.
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PMID:c-Met tyrosine kinase receptor expression and function in human and canine osteosarcoma cells. 1452 31

To further define the role of insulin-like growth factor-1 (IGF-1) and its receptor (IGF-1R) in osteosarcoma (OS), human OS cell lines with low (SAOS-2) and high (SAOS-LM2) metastatic potential and three canine OS-derived cell lines were studied. Cell lines were evaluated for: IGF-1R expression; expression of IGF binding proteins (IGFBPs); effect of IGF-1 on tumor cell growth, invasion, expression of urokinase plasminogen activator (uPA), and soluble uPA receptor (suPAR), and; ectopic and orthotopic tumorigenicity of the canine OS cells in athymic mice. All cell lines exhibited steady-state mRNA expression of IGF-1R. The SAOS-2 and SAOS-LM2 cells expressed 9,138 and 10,234 cell-associated binding sites, respectively. Canine OS cells expressed from 1,728 to 3,883 binding sites. Two IGF-1-treated cell lines displayed enhanced proliferation. Two cell lines formed colonies in semisolid media, and IGF-1 increased colony number. Matrigel invasion was enhanced in one cell line following IGF-1 treatment. uPA and suPAR were unchanged in SAOS-2 and SAOS-LM2 cells following IGF-1 treatment, but the highly metastatic OS line SAOS-LM2 expressed five times more suPAR and displayed enhanced invasion compared to the parental, low metastatic SAOS-2. IGFBP-5 was detected in four of five cell lines, and IGFBP-3 was detected in two canine OS cell lines. Two canine OS lines were tumorigenic, and one metastasized spontaneously. In conclusion, OS cells express IGF-1R, which can contribute to their growth and invasion. There is suggestive evidence that increasing receptor number may contribute to in vivo tumorigenesis. Additional studies are needed to determine how IGF-1/IGF-1R interactions contribute to the malignant phenotype of OS.
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PMID:IGF-1 receptor contributes to the malignant phenotype in human and canine osteosarcoma. 1509 5

FSAP (Factor VII-activating protease) is a new plasma-derived serine protease with putative dual functions in haemostasis, including activation of coagulation Factor VII and generation of urinary-type plasminogen activator (urokinase). The (auto-)activation of FSAP is facilitated by polyanionic glycosaminoglycans, such as heparin or dextran sulphate, whereas calcium ions stabilize the active form of FSAP. In the present study, extracellular RNA was identified and characterized as a novel FSAP cofactor. The conditioned medium derived from various cell types such as smooth muscle cells, endothelial cells, osteosarcoma cells or CHO (Chinese-hamster ovary) cells contained an acidic factor that initiated (auto-)activation of FSAP. RNase A, but not other hydrolytic enzymes (proteases, glycanases and DNase), abolished the FSAP cofactor activity, which was subsequently isolated by anion-exchange chromatography and unequivocally identified as RNA. In purified systems, as well as in plasma, different forms of natural RNA (rRNA, tRNA, viral RNA and artificial RNA) were able to (auto-)activate FSAP into the two-chain enzyme form. The specific binding of FSAP to RNA (but not to DNA) was shown by mobility-shift assays and UV crosslinking, thereby identifying FSAP as a new extracellular RNA-binding protein, the K(D) estimated to be 170-350 nM. Activation of FSAP occurred through an RNA-dependent template mechanism involving a nucleic acid size of at least 100 nt. In a purified system, natural RNA augmented the FSAP-dependent Factor VII activation several-fold (as shown by subsequent Factor Xa generation), as well as the FSAP-mediated generation of urokinase. Our results provide evidence for the first time that extracellular RNA, present at sites of cell damage or vascular injury, can serve an important as yet unrecognized cofactor function in haemostasis by inducing (auto-)activation of FSAP through a novel surface-dependent mechanism.
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PMID:Extracellular RNA is a natural cofactor for the (auto-)activation of Factor VII-activating protease (FSAP). 1565 66

The urokinase-type plasminogen activator (uPA) receptor (uPAR) has been implicated in signal transduction and biological processes including cancer metastasis, angiogenesis, cell migration, and wound healing. It is a specific cell surface receptor for its ligand uPA, which catalyzes the formation of plasmin from plasminogen, thereby activating the proteolytic cascade that contributes to the breakdown of extracellular matrix, a key step in cancer metastasis. We have synthesized three different DNA enzymes (Dz372, Dz483 and Dz720) targeting uPAR mRNA at three separate purine (A or G)-pyrimidine (U or C) junctions. Two of these DNAzymes, Dz483 and Dz720, cleaved uPAR transcript in vitro with high efficacy and specificity at a molar ratio (uPAR to Dz) as low as 1 : 0.2. When analyzed over 2 h with a 200-fold molar excess of DNAzymes to uPAR transcript, Dz720 and Dz483 were able to decrease uPAR transcript in vitro by approximately 93% and approximately 84%, respectively. They also showed an ability to cleave uPAR mRNA in the human osteosarcoma cell line Saos-2 after transfection. The DNAzyme Dz720 decreased uPAR mRNA within 4 h of transfection, and inhibited uPAR protein concentrations by 55% in Saos-2 cells. The decrease in uPAR mRNA and protein concentrations caused by Dz720 significantly suppressed Saos-2 cell invasion as assessed by an in vitro Matrigel assay. The use of DNAzyme methodology adds a new potential clinical agent for decreasing uPAR mRNA expression and inhibiting cancer invasion and metastasis.
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PMID:Inhibition of urokinase receptor gene expression and cell invasion by anti-uPAR DNAzymes in osteosarcoma cells. 1600 57

A number of recent studies suggest that mitochondrial function is a player in tumor development and progression. In this study, we have used gene expression arrays to examine transcriptional differences between oxidative phosphorylation (OXPHOS)-competent and OXPHOS-impaired human osteosarcoma cells. Genes associated with extracellular matrix remodeling, including members of the matrix metalloproteinases (MMPs) and tissue inhibitors of the MMP (TIMP) family, urokinase plasminogen activator and its inhibitor plasminogen-activator inhibitor-1 (PAI1), and CTGF and CYR61 (members of the Cysteine-rich 61, Connective Tissue Growth Factor and Nephroblastoma-overexpressed (CCN) gene family of growth regulators), were among the ones significantly altered in the OXPHOS-deficient cells. These changes were confirmed by RT-PCR and promoter reporter assays. Alterations at the protein level for some of these factors were also observed, though at a lower magnitude, with the exception of TIMP1, where a marked change in steady-state levels of the protein was observed after induction of OXPHOS dysfunction. Repopulation of mitochondrial DNA (mtDNA)-less cells with wild-type mtDNA reduced matrigel invasion, whereas repopulation with a mutated mtDNA did not. Taken together our data suggests that OXPHOS dysfunction modulates the invasive phenotype by transcriptional regulation of genes coding for members of the MMP/TIMP system, urokinase plasminogen activator/plasminogen-activator inhibitor I and CCN proteins.
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PMID:Oxidative phosphorylation dysfunction modulates expression of extracellular matrix--remodeling genes and invasion. 1622 32

Interleukin-1 (IL-1) plays key roles in altering bone matrix turnover. This turnover is regulated by matrix metalloproteinases (MMPs), tissue inhibitor of matrix metalloproteinases (TIMPs), and the plasminogen activation system, including tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA) , and plasminogen activator inhibitor type-1 (PAI-1). In this study, we examined the effect of IL-1alpha on the expression of the MMPs, TIMPs, tPA, uPA, and PAI-1 genes in osteoblasts derived from the rat osteosarcoma cell line ROS 17/2.8. The cells were cultured in alpha-minimum essential medium containing 10% fetal bovine serum with 0 or 100 U/ml of IL-1alpha for up to 14 days. The levels of MMPs, TIMPs, uPA, tPA, and PAI-1 expression were estimated by determining the mRNA levels using real-time RT-PCR and by determining protein levels using ELISA. In IL-1alpha cultures, the expression levels of MMP-1, -2, -3, -13, and -14 exceeded that of the control through day 14 of culture, and the expression of MMPs increased markedly from the proliferative to the later stages of culture. The TIMP-1, -2, and -3 expression levels increased from the initial to the proliferative stages of culture. The expression of tPA increased greatly during the proliferative stage of culture, and uPA expression increased throughout the culture period, increasing markedly from the proliferative to the later stages of culture. In contrast, PAI-1 expression decreased in the presence of IL-1alpha through day 14. These results suggest that IL-1alpha stimulate bone matrix turnover by increasing MMPs, tPA, and uPA production and decreasing PAI-1 production by osteoblasts, and incline the turnover to the resolution.
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PMID:The effect of IL-1alpha on the expression of matrix metalloproteinases, plasminogen activators, and their inhibitors in osteoblastic ROS 17/2.8 cells. 1631 28

The uPA/uPAR system is involved in tumour progression and metastasis of a variety of cancers. Previously, we have shown that increased expression of urokinase plasminogen activator (uPA) correlated with malignancy grade in certain sarcomas. A study looking at in vivo inhibition of this system has not been done to date for osteosarcoma. More recently, this laboratory developed a clinically relevant mouse model where intratibial injection of UMR106-01 cells resulted in the development of osteosarcoma and lung metastases. Expression of uPA and its receptor (uPAR) were localised to the invading front of the tumours. Pulmonary metastasis is a predominant feature of the disease and is the major cause of death in patients. In the present study, the effects of down-regulating uPAR were observed in vitro and in vivo. UMR106-01 cells were transfected with either antisense-uPAR or vector control plasmids. Two antisense clones, exhibiting uPAR downregulation, demonstrated decreased adhesion, migration and invasion in cell-based assays in vitro (P<0.05). Cellular proliferation was not affected by uPAR downregulation. In vivo, a marked reduction of 80% in tibial tumour volumes (P<0.05), and total inhibition of pulmonary metastases were observed in mice injected with the more potent of the antisense clones. This study proves seminally the usefulness of uPAR antisense in curbing the growth and spread of osteosarcoma.
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PMID:Downregulation of uPAR confirms link in growth and metastasis of osteosarcoma. 1664 73

Silibinin is a natural flavonoid antioxidant with anti-hepatotoxic properties and pleiotropic anticancer capabilities. We tested the hypothesis that silibinin inhibits cellular invasiveness by down-regulating the focal adhesion kinase (FAK) and extracellular signal-regulated protein kinase (ERK)-dependent c-Jun/activator protein-1 (AP-1) induction, which leads to inhibition of urokinase-type plasminogen activator (u-PA) and matrix metalloproteinase-2 (MMP-2) expressions in human osteosarcoma MG-63 cells. We found that silibinin decreased cell adhesion and invasiveness, as well as inhibited u-PA and MMP-2 expressions. Silibinin reduced ERK 1/2 phosphorylation, but had no effects on the phosphorylation of c-Jun N-terminal kinases (JNKs) 1/2, p38 and Akt. Silibinin suppressed AP-1-binding activity and c-Jun levels and its phosphorylation without changes of c-Fos and Ets-1 levels. Silibinin also inhibited interleukin-6-induced ERK 1/2 and c-Jun phosphorylation, and cell invasiveness. Thus, silibinin may possess an anti-metastatic activity in MG-63 cells.
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PMID:Silibinin suppresses human osteosarcoma MG-63 cell invasion by inhibiting the ERK-dependent c-Jun/AP-1 induction of MMP-2. 1711 26

Osteosarcoma (OS) is a cancer which afflicts the bone, ending in usually fatal lung metastasis mainly in teenagers and adolescents. We have recently shown that PEDF is one biological that has multiple anti-OS activity. In parallel, we have also shown using rodent cells, the beneficial effects of downregulation of uPAR against OS. Here, we provide further proof of such effects of uPAR downregulation using human OS cells and combine this with PEDF treatment. We describe the involvement of uPAR with activity of PEDF. In silico, PEDF did not bind to uPA and thus did not attenuate its activity. In the presence of exogenous PEDF, both uPA, its receptor and FAK localize intracellularly. Blocking of uPA and uPAR on the cell surface increased the binding of PEDF, whether endogenous or exogenous. In clinical specimens of OS, there was mutually exclusive expression of PEDF and uPAR at the growing edge of the tumor. Incubation of cells with PEDF and a uPAR antibody led to an increased reduction in invasion of cells through Matrigel, and a heightened apoptotic signal. In vivo, treatment of human OS cells with both PEDF and uPAR DNAzyme resulted in greater primary tumor growth, pulmonary metastasis inhibition and decreased osteolysis. Areas of necrosis were noted in the PEDF-administered group of animals. This study shows an association between two very important systems involved in tumor progression and highlights the possibility that a combined approach of PEDF exposure and uPAR knockdown may lead to a better targeted outcome against OS.
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PMID:uPAR mediates anticancer activity of PEDF. 1848 55


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