Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0265264 (HOS)
 1,119 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is well known that interferons inhibit cell growth. However, we found that human interferon-gamma (HuIFN-gamma) enhanced the growth of human osteosarcoma cells, HOS-Y1 cells, in a dose-dependent manner. This enhancing effect was found only under the following conditions: when the cells were precultured for 2 or 3 days and then treated with HuIFN-gamma for 2, 3, or 4 days, and when the cells were seeded at a density of 1,000 or 2,000 cells/well. The degree of enhancement of cell growth was maximum when the cells were precultured at a density of 1,000 cells/well for 3 days and then treated with HuIFN-gamma for 2 days. The enhancing effect of HuIFN-gamma disappeared in the presence of anti-HuIFN-gamma antibody. In addition, it was found that the conditioned medium from HOS-Y1 cells enhanced the growth of HOS-Y1 cells, and that the conditioned medium from HOS-Y1 cells cultured with HuIFN-gamma enhanced the cell growth more than that from cells cultured without HuIFN-gamma. Epidermal growth factor (EGF), acidic fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF), and transforming growth factor-beta 1(TGF-beta 1) did not enhance the growth of HOS-Y1 cells. These results suggest that HuIFN-gamma enhanced the cell growth by augmenting the production of unknown growth factor(s) in HOS-Y1 cells via an autocrine mechanism.
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PMID:Enhancement of the growth of human osteosarcoma cells by human interferon-gamma. 147 55

The protein kinase C (PKC) enzyme family consists of at least 11 isozymes in three classes, with characteristic tissue distributions. Phorbol esters activate and ultimately down-regulate phorbol-sensitive isozymes. PKC is a signal transducer in bone, and phorbol esters influence bone resorption. Little is known about specific PKC isozymes in this tissue, however. We describe here the expression and phorbol ester-induced down-regulation of PKC isozymes in osteoblasts. Normal mouse osteoblasts and seven osteoblastic cell lines (rat UMR-106, ROS 17/2.8, ROS 24/1, and human MG-63, G-292, SaOS-2, HOS-TE85) were screened for isozyme expression by Western immunoblotting using isozyme-specific anti-PKC antibodies. The conventional alpha and beta I isozymes, but not gamma, were present in each of the osteoblasts examined; PKC-beta II was detectable in all but the ROS 24/1 line. PKC-epsilon was expressed in all osteoblasts screened, but other novel PKCs, delta, eta, and theta, were detectable only in select lines. The atypical zeta and iota/lambda PKCs were in all osteoblasts examined. To determine the sensitivity of the isozymes to prolonged phorbol ester treatment, normal osteoblasts and the UMR-106 cell line were treated with vehicle or 1 microM phorbol 12, 13-dibutyrate (PDB) for 1, 3, 6, 12, 24, or 48 h, and Western blot analysis was performed. Normal and UMR-106 cells showed similar phorbol sensitivities; conventional (alpha, beta I) and novel (delta, epsilon, eta) isozymes were down-regulated by prolonged phorbol treatment but atypical isozymes were not. Down-regulation of all sensitive PKCs was detectable within 6 h of phorbol treatment; the novel delta and epsilon isozymes, however, showed more rapid and dramatic down-regulation than conventional isozymes. The observed down-regulation was dose-dependent (0.3-3 microM) and specific; 48 h treatment with the inactive phorbol, 4 alpha-phorbol 12,13-didecanoate (4 alpha-PDD), failed to down-regulate PDB-sensitive isozymes. The phorbol-induced down-regulation was also reversible; 24 h after withdrawing PDB, all phorbol-sensitive isozymes, except PKC-eta, had recovered at least partially. These studies, the first to characterize thoroughly PKC isozyme expression in osteoblastic cells from several species, demonstrate that osteoblasts have a characteristic PKC isozyme profile, including both phorbol ester-sensitive and -insensitive isozymes. The time course of down-regulation and the presence of phorbol-insensitive PKCs must be considered in interpreting the effects of phorbol esters on bone remodeling.
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PMID:Expression and phorbol ester-induced down-regulation of protein kinase C isozymes in osteoblasts. 897 Aug 87

Recently we found that primary human osteoblast-like cells (HOBs) support hematopoietic progenitor cells (assayed by colony formation in methylcellulose) and long-term culture initiating (LTC-IC) activity in vitro. In the present investigation, we evaluate whether human osteosarcoma cells share in these activities. We observed that relative to controls, significantly fewer hematopoietic colonies were formed in the presence of HOS TE85, MG-63, SaOS-2, or U2-OS human osteosarcomas. In addition, neither MG-63 or SaOS-2 cells supported hematopoietic progenitor cell activity or LTC-IC activity in vitro. We established that the suppressive activity produced by the osteosarcomas is soluble, correlated with osteosarcoma cell number and is partially neutralized with antibody to TGF-beta 1,2,3. While it is clear that the osteosarcomas express several phenotypic characteristics of primary human osteoblasts, these data suggest that they may be functionally disregulated with regard to their ability to support normal hematopoiesis. For these reasons, caution should be exercised when evaluating osteoblastic and hematopoietic cell interactions based purely on the use of osteosarcoma cell lines.
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PMID:Human osteosarcomas inhibit hematopoietic colony formation: partial reversal by antibody to transforming growth factor-beta 1. 931 39

Cultured rodent osteoblastic cells reiterate the phenotypic differentiation and maturation of osteoblasts seen in vivo. As previously shown, the human osteosarcoma cell line HOS 58 represents a differentiated stage of osteoblast development. The potential of HOS 58 for still further in vitro differentiation suggests the line can serve as a model of osteoblast maturation. Using this cell line, we have investigated the influence of 1,25-(OH)2-D3 (D3), TGF-beta and Dexamethasone (Dex) on proliferation and on the protein and mRNA levels of alkaline phosphatase (AP), procollagen 1 (Col 1), and osteocalcin (Oc), as well as mineralization during 28 days in culture. AP mRNA and protein were highly expressed throughout the culture period with further increase of protein AP activity at constant gene expression levels. A differentiation inhibiting effect of either TGF-beta or Dex was seen. Col 1 was investigated without the use of ascorbic acid and showed only minor changes during culture time or stimulation. The gene expression for Oc increased continually whereas protein synthesis peaked at confluence and decreased thereafter. TGF-beta and Dex treatments decreased Oc mRNA and protein levels. Stimulation by D3 was maximal at day 7 with a decrease thereafter. HOS 58 cells showed no mineralization capacity when stimulated with different agents, as measured by energy-dispersive X-ray microanalysis. This was not due to absence of Cbfa1 expression. In conclusion, the HOS 58 osteosarcoma cell line represents a differentiated cell line with highly expressed and physiologically regulated AP expression during further differentiation in culture. We observed a dissociation between osteocalcin gene expression and protein secretion which may contribute to the lack of mineralization in this cell line.
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PMID:Prolonged culture of HOS 58 human osteosarcoma cells with 1,25-(OH)2-D3, TGF-beta, and dexamethasone reveals physiological regulation of alkaline phosphatase, dissociated osteocalcin gene expression, and protein synthesis and lack of mineralization. 1194 84

alpha2-HS-glycoprotein (Ahsg), also known as fetuin is a serum and bone resident glycoprotein, which binds to TGF-beta superfamily members including bone morphogenetic proteins (BMP) and inhibits dexamethasone-induced osteogenesis in bone marrow cultures in vitro. Here we demonstrate that Ahsg reduces cytokine binding to its cognate receptor in HOS osteocyte cells and suppresses intracellular signaling, while in vivo, we test the hypothesis that Ahsg-deficient mice are hyper-responsive to BMP-induced osteogenesis. Human native BMP was implanted into the hindquarter muscles of Ahsg(+/+), Ahsg(+/-) and Ahsg(-/-) mice and 4 weeks later, ossicle formation was analyzed by radiography, bone density scanning (DEXA) and histomorphometry. Alkaline phosphatase (AP) activity was measured in ossicles as a marker for bone cell differentiation, and was significantly higher in Ahsg(-/-) versus Ahsg(+/-) and/or Ahsg(+/+) mice. Ectopic ossicle size in the Ahsg(+/-) mouse was 4-fold greater than that in the wild type (Ahsg(+/+)), and intermediate to that shown in Ahsg(-/-) mouse. Bone mineral density (BMD) was lower in the Ahsg(-/+) and Ahsg(-/-) mice compared to Ahsg(+/+) littermates. The ratio of cortical to cancellous bone was found to be >2-fold higher in Ahsg(-/-) mouse in comparison to the Ahsg(+/+) mice with no significant change in the Ahsg(-/+) mouse. Finally, a significantly higher incidence of satellite ossification; small islands of immature bone, was shown in Ahsg(-/-) mice as compared to Ahsg(+/+) mice. Although Ahsg binds to TGF-beta/BMP and blocks receptor signalling, it may also sequester cytokines in matrix, thereby acting as a reservoir of osteoinductive activity when released. This may explain the non-linear relationship between ectopic bone formation characteristics and Ahsg(+/+), Ahsg(+/-) and Ahsg(-/-) genotypes, although the increase in satellite bone formation might also explain this phenomenon. Our results suggest that Ahsg may be useful for prevention of the heterotopic ossification and the regulation of osteoinductive effects of BMP used with grafts.
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PMID:Regulation of BMP-induced ectopic bone formation by Ahsg. 1588 88

Degradation of extracellular matrix (ECM) is a hallmark of tumor invasion, metastasis and angiogenesis. Based on the Rath multitargeted approach to cancer using natural substances to control ECM stability and enhancing its strength, we developed a novel formulation (NM) of lysine, proline, ascorbic acid and green tea extract that has shown significant anti-cancer activity against a number of cancer cell lines. The aim of the present study was to determine whether NM exhibits anti-angiogenic and anti-metastatic effects using in vitro and in vivo experimental models. Angiogenesis was measured using a chorioallantoic membrane (CAM) assay in chick embryos and bFGF-induced vessel growth in C57BL/6J female mice. To determine the in vivo effect of NM on the tumor xenograft growth, male nude mice were inoculated with 3 x 10(6) MNNG-HOS cells. Control mice were fed a mouse chow diet, while the test group was fed a mouse chow diet supplemented with 0.5% NM for 4 weeks. In vitro studies on cell proliferation (MTT assay), MMP expression (zymography) and Matrigel invasion were conducted on human osteosarcoma U2OS, maintained in McCoy medium, supplemented with 10% FBS, penicillin and streptomycin in 24-well tissue culture plates and tested with NM at 0, 10, 50, 100, 500, and 1000 microg/ml in triplicate at each dose. NM at 250 microg/ml caused a significant (p<0.05) reduction in bFGF-induced angiogenesis in CAM. NM inhibited tumor growth of osteosarcoma MNNG-HOS cell xenografts in nude mice by 53%; furthermore, tumors in NM-treated mice were less vascular and expressed lower levels of VEGF and MMP-9 immunohistochemically than tumors in the control group. In addition, NM exhibited a dose-dependent inhibition of osteosarcoma U2OS cell proliferation (up to 60% at 1000 microg/ml), MMP-2 and -9 expression (with virtual total inhibition at 500 microg/ml NM), and invasion through Matrigel (with total inhibition at 100 microg/ml NM). Moreover, NM decreased U2OS cell expression of VEGF, angiopoietin-2, bFGF, PDGF and TGFbeta-1. These results together with our earlier findings suggest that NM is a relatively non-toxic formulation, which inhibits growth, invasion, metastasis, and angiogenesis of tumor cells.
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PMID:Inhibitory effect of a mixture containing ascorbic acid, lysine, proline and green tea extract on critical parameters in angiogenesis. 1614 36

The epidermal growth-factor receptor (EGFR) tyrosine kinase inhibitor erlotinib has been proven to be highly effective in the treatment of nonsmall cell lung cancer (NSCLC) harboring oncogenic EGFR mutations. The majority of patients, however, will eventually develop resistance and succumb to the disease. Recent studies have identified secondary mutations in the EGFR (EGFR T790M) and amplification of the N-Methyl-N'-nitro-N-nitroso-guanidine (MNNG) HOS transforming gene (MET) oncogene as two principal mechanisms of acquired resistance. Although they can account for approximately 50% of acquired resistance cases together, in the remaining 50%, the mechanism remains unknown. In NSCLC-derived cell lines and early-stage tumors before erlotinib treatment, we have uncovered the existence of a subpopulation of cells that are intrinsically resistant to erlotinib and display features suggestive of epithelial-to-mesenchymal transition (EMT). We showed that activation of TGF-beta-mediated signaling was sufficient to induce these phenotypes. In particular, we determined that an increased TGF-beta-dependent IL-6 secretion unleashed previously addicted lung tumor cells from their EGFR dependency. Because IL-6 and TGF-beta are prominently produced during inflammatory response, we used a mouse model system to determine whether inflammation might impair erlotinib sensitivity. Indeed, induction of inflammation not only stimulated IL-6 secretion but was sufficient to decrease the tumor response to erlotinib. Our data, thus, argue that both tumor cell-autonomous mechanisms and/or activation of the tumor microenvironment could contribute to primary and acquired erlotinib resistance, and as such, treatments based on EGFR inhibition may not be sufficient for the effective treatment of lung-cancer patients harboring mutant EGFR.
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PMID:TGF-beta IL-6 axis mediates selective and adaptive mechanisms of resistance to molecular targeted therapy in lung cancer. 2071 23

We previously reported the presence of vasculogenic mimicry (VM) in human osteosarcoma. However, the mechanistic basis of osteosarcoma VM remains unclear. Three hundred eighty-one upregulated differentially expressed genes (DEGs) and 526 downregulated DEGs between human osteosarcoma cell line 143B and HOS cell exposed to Matrigel were screened out by microarray. GO categories such as "cell adhesion", "angiogenesis" were enriched in 143B group. PATHWAY analysis showed enriched TGF-beta, Wnt and VEGF signaling pathway in 143B group. The hub gene ITGA2 in signal-network of DEGs exhibited pro-VM and pro-metastasis effect. Our study provides fundamental data for further studies regarding molecules involved in osteosarcoma VM.
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PMID:Identification of potential crucial genes associated with vasculogenic mimicry in human osteosarcoma based on gene expression profile. 3188 99