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)

Insulin-like growth factor-binding proteins (IGFBPs) in rat serum, lymph, amniotic fluid and cerebrospinal fluid (CSF), and in rat cell-conditioned media were characterized using a combination of gel-permeation chromatography, Western immunoblots and Western-ligand analysis. Adult serum and abdominal lymph contained a 200 kDa IGFBP (the putative type-II IGF receptor) and a 150 kDa IGFBP that contained subunits of 40-50 kDa aligning with porcine IGFBP-3 on Western-ligand blots. In addition, both fluids contained the smaller IGFBPs: a 30 kDa IGFBP which was immunoreactive with IGFBP-2 antiserum, a 28 kDa IGFBP which electrophoresed with human IGFBP-1, and a 24 kDa IGFBP. In contrast, fetal serum and amniotic fluid lacked the 150 kDa and the 28 kDa IGFBPs. CSF contained only a 30 kDa IGFBP, but this was not IGFBP-2. Several IGFBPs were detected in media conditioned by liver, bone and muscle cells. Liver-derived cells and some hepatoma cell lines produced similar patterns upon ligand blot analysis, i.e. IGFBPs of 30 kDa (which reacted with IGFBP-2 antiserum), 28 kDa and 24 kDa. A hepatoma cell line, HTC, and a smooth muscle cell line contained only an IGFBP of 26 kDa. Skeletal muscle-derived cells (L6 myoblasts) produced a 28 kDa, a 26 kDa and a 24 kDa IGFBP. Both calvarial osteoblasts and osteogenic sarcoma cells produced an IGFBP of 30 kDa that cross-reacted with IGFBP-2 antisera. In addition, osteogenic sarcoma cells produced a 28 kDa and a 24 kDa IGFBP. These results allow us partially to classify and to compare the IGFBPs in rat fluids and those produced by cultured cells.
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PMID:Characterization of insulin-like growth factor-binding proteins in rat serum, lymph, cerebrospinal and amniotic fluids, and in media conditioned by liver, bone and muscle cells. 170 42

GH exerts its biological actions on osteoblasts through a specific high affinity receptor expressed on these cells. GH receptor binding is positively modulated by a number of factors, including retinoic acid and dexamethasone, whereas fetal calf serum strongly decreases the binding. To identify responsible factors in serum, components of serum, the insulin-like growth factors (IGFs)-I and -II, and IGF binding proteins (IGFBPs)-2 and -3 were tested for a possible negative modulatory role. IGF-I and -II decreased [125I]hGH binding at an optimal concentration of 30 ng/ml for IGF-I and 100 ng/ml IGF-II, reducing the binding to 51% and 55%, respectively, of control values. A stimulation of [125I]hGH binding was observed with IGFBP-2 as well as IGFBP-3, inducing an increase to 148% and 151% of control binding at an optimal concentration of 3000 ng/ml for both peptides. The effects of all peptides were dependent on the incubation time, being significantly increased after 8 h of incubation and reaching the full effect thereafter. The effects were declined at 24 h compared with 16 h for IGFBP-2 and -3 but not for IGF-I and -II. Coincubation of the cells with IGF-I and -II and IGFBP-2 and -3 neutralized the effects of the factors alone. In conclusion, these results show that IGF-I and -II on the one hand and IGFBP-2 and -3 on the other hand exert opposite actions on [125I]hGH binding, IGFBP-2 and -3 exerting probably an IGF-independent effect. Further, IGF-I and -II decreased GH receptor messenger RNA (mRNA) levels, as quantified by a solution hybridization ribonuclease protection assay, from 8.65 +/- 1.78 attomoles (amol)/microgram DNA (control) to 2.4 +/- 0.68 and 2.16 +/- 0.92 amol/microgram DNA, respectively. IGFBP-2 increased GH receptor mRNA levels from 5.26 +/- 1.17 (control) to 13.19 +/- 3.48. Incubation with IGFBP-3 did not result in stimulation of GH receptor mRNA levels (8.59 +/- 2.91 amol/microgram DNA). This shows that the mechanism of regulation of the GH receptor is, except for IGFBP-3, at least in part on the mRNA level. Lastly, IGFBP-2 and IGFBP-3 are mitogenic for UMR-106.01 rat osteosarcoma cells, inducing an increase in cell number to 125% and 142% of control cell counts after 48 h of incubation with 1000 ng/ml IGFBP-2 and -3, whereas IGF-I, IGF-II and Long R3 IGF-I did not stimulate proliferation. IGFBP-2 and -3 potentiate hGH induced mitogenesis at low hGH concentrations of both factors, whereas at higher concentrations no such effect is observed.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Insulin-like growth factor binding proteins-2 and -3 stimulate growth hormone receptor binding and mitogenesis in rat osteosarcoma cells. 754 1

The transplantation of PA-III rat prostate cancer cells onto rat skeleton produces osteoblastic metastases. Therefore w e studied the paracrine interactions between the PA-III cells and osteoblast-derived osteosarcoma cells (UMR 106 cells). A serine protease secreted by PA-III cells hydrolyzed IGF-binding protein-1 and IGF-binding protein-2 (IGFBP-1 and IGFBP-2) detected in the cell culture media (CM) of OMR 106 cells by western ligand blotting. The serine protease of PA-III cell CM was purified using a benzamidine affinity column. This protease was a protein of 45-50 kDa on polyacrylamide gel electrophoresis under non-reducing conditions but generated two protein bands under reducing conditions; a) one of 33-35 kDa possessing protease activity and b) another of 20-25 kDa which was proteinolytically inactive. Sequence analysis identified the amino acid sequence of the a-chain (20-25 kDa band) and of the b-chain (33-35 kDa band) of rat urokinase-type plasminogen activator molecule. Urokinase purified from PA-III cell CM hydrolyzed IGFBPs of UMR 106 cells and stimulated the proliferation of UMR 106 cells in serum-free cultures. Its protease activity was abolished by benzamidine and aprotinin. Its mitogenic activity for osteoblasts was inhibited by anti-IGF-I monoclonal antibody. Northern blot analysis documented the expression of the urokinase-type plasminogen activator gene in the mRNA extracted from PA-III cells. Urokinase expression was inhibited by dexamethasone. Therefore, we conclude that urokinase-type plasminogen activator stimulates osteoblasts via an IGF-I dependent mechanism. Hydrolysis of the IGFBOPs at the sites of PA-III cell-induced bone tumors account for an increased bioavailability of IGFs. This may facilitate the development and the growth of PA-III cell-induced bone tumor and can also mediate the subsequent local osteoblastic reaction.
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PMID:Urokinase-type plasminogen activator: a paracrine factor regulating the bioavailability of IGFs in PA-III cell-induced osteoblastic metastases. 768 89

Insulin-like growth factors (IGFs) and their specific regulatory binding proteins (IGFBPs) are postulated to play a key role in bone metabolism. To date, IGFBP-2 through -6 have been characterized in bone cell systems. In this study we focused on IGFBP-1. Primary cultures of normal human osteoblasts derived from trabecular bone (hOB cells) expressed low levels of IGFBP-1 messenger RNA (mRNA), as determined by Northern analyses. Treatment of hOB cells with 1 microM cortisol or 100 nM dexamethasone for 20 h stimulated IGFBP-1 mRNA expression 5-fold and increased levels of immunoassayable IGFBP-1 in the conditioned medium 3-fold. Estradiol and progesterone had no effect. IGFBP-1 expression was not observed in U-2, TE-85, or MG-63 human osteosarcoma cell lines or in normal human fibroblasts. Insulin (1-100 nM) potently inhibited both basal and glucocorticoid-stimulated IGFBP-1 expression in hOB cells. Insulin had little or no effect on steady state levels of the other IGFBP mRNA. A monoclonal antibody to the insulin receptor blocked insulin binding to insulin receptors and completely prevented insulin-induced suppression of IGFBP-1. In summary, we have documented IGFBP-1 mRNA and protein expression in normal nontransformed human osteoblastic cells. This expression was stimulated by glucocorticoids and inhibited by insulin in a manner similar to IGFBP-1 regulation in hepatocytes. Insulin acts through insulin receptors on hOB cells. We postulate that IGFBP-1 produced by osteoblasts in vivo can modulate local actions of IGF on bone formation in response to changes in glucocorticoid and insulin concentrations.
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PMID:Insulin-like growth factor-binding protein-1 expression in cultured human bone cells: regulation by insulin and glucocorticoid. 875 54

Normal osteoblasts from newborn rat calvaria and human osteosarcoma (Saos-2) cells express IGFBP-5 mRNA. IGF I increases IGFBP-5 mRNA levels in both cell types, whereas retinoic acid stimulates IGFBP-5 mRNA expression in calvaria but suppresses it in Saos-2 cells. IGFBP-5 mRNA expression is stimulated in normal bone cells by parathyroid hormone. 30 nM IGFBP-5 stimulates 3H-thymidine incorporation in calvaria (which produce IGF I contributing to basal proliferation in serum-free medium) but not in Saos-2 cells which produce little IGF I and IGF II. Among the 5 rhIGFBPs tested (IGFBP-2 to -6), only IGFBP-5 stimulates DNA synthesis in calvaria cells, and only IGFBP-6 in Saos-2 cells. RhIGFBP-5 displays a short half-life (approximately 30 min) in serum-free medium of calvaria cells and a long half-life (approximately 15 h) in the medium of Saos-2 cells. Fragments of 20 and 14 kDa accumulate in the media of both cell types. Intact (31 kDa) IGFBP-5 is associated and remains with the extracellular matrix of mature calvaria osteoblasts but not of Saos-2 cells. Among the IGFBPs produced IGFBP-5 is unique with regard to its marked affinity to matrix of normal bone cells, its short half-life when released, and its stimulatory effects on DNA synthesis.
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PMID:Expression, effects, and fate of IGFBP-5 are different in normal and malignant osteoblastic cells. 881 58

Insulin-like growth factor I (IGF-I) has acute insulin-like metabolic effects and long-term anabolic actions offering a range of important therapeutic applications. To evaluate a system for large-scale production of this peptide in the mammary glands of transgenic livestock, we generated transgenic rabbits carrying fusion genes in which a synthetic DNA coding for human IGF-I (hIGF-I) was placed under the transcriptional control of regulatory elements isolated from the bovine alpha S1-casein (alpha S1-cas) gene. Western blot analysis of milk from alpha S1-cas-hIGF-I transgenic rabbits demonstrated production of high amounts of mature hIGF-I peptide (7.6 kDa). Quantitative analysis by RIA revealed hIGF-I levels between 50 and 300 micrograms/ml milk. Recombinant hIGF-I purified from the milk of alpha S1-cas-hIGF-I transgenic rabbits bound to IGF-I receptors on human IM-9 lymphoblasts and stimulated DNA synthesis by growth-arrested MG-63 human osteosarcoma cells as efficiently as hIGF-I produced in Escherichia coli. Ligand blot analysis of milk serum revealed the presence of 45-kDa, 30-kDa, and 23-kDa IGF-binding proteins (IGFBPs). The 30-kDa IGFBP was shown to be IGFBP-2 by immunoprecipitation using an antiserum raised against human IGFBP-2. Secretion of IGFBP-2 was markedly stimulated by hIGF-I overproduction in alpha S1-cas-hIGF-I transgenic rabbits. The latter displayed slightly increased milk yield, but no significant changes in total protein content or overall milk protein composition, and reared their offspring without any problems or clinical signs of impaired welfare, even after multiple lactations. Our results indicate that high amounts of biologically active hIGF-I can be produced in the mammary glands of alpha S1-cas-hIGF-I transgenic rabbits. Local production of hIGF-I in mammary tissue is associated with increased secretion of IGFBP-2, which may prevent major biological effects by high levels of hIGF-I on the mammary gland.
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PMID:Human insulin-like growth factor I (IGF-I) produced in the mammary glands of transgenic rabbits: yield, receptor binding, mitogenic activity, and effects on IGF-binding proteins. 897 18

Insulin-like growth factor (IGF) I is a potent mitogen for human osteosarcoma cells such as the Saos-2/B-10 cell line. IGF binding proteins (IGFBPs) prevent stimulation of DNA synthesis by IGFs. In contrast to recombinant human (rh) IGFBP-2, -3, -4, and -5, 10-100 nM rhIGFBP-6 stimulated [(3)H]thymidine incorporation into DNA and multiplication of Saos-2/B-10 cells. Upon withdrawal of serum, 30 nM IGFBP-6 also decreased apoptosis (within 4 h) and increased protein content and sodium-dependent phosphate uptake (within 24 h), but less potently than IGF I. (125)I-labeled rhIGFBP-6 did not bind to the cells, and cold IGFBP-6 did not affect (125)I-labeled IGF I binding. Production of IGF I, IGF II, and IGFBP-6 by the cells or significant degradation of rhIGFBP-6 could not be detected within 24 h of incubation. Thus, among the rhIGFBPs tested, rhIGFBP-6 is unique in stimulating osteosarcoma cell growth. Furthermore, it has an antiapoptotic effect.
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PMID:Mitogenic and antiapoptotic effects of insulin-like growth factor binding protein-6 in the human osteoblastic osteosarcoma cell line Saos-2/B-10. 1051 58

The insulin-like growth factors I and II (IGF-I, IGF-II), their receptors, and high affinity binding proteins (IGFBPs) represent a family of cellular modulators that play essential roles in the development and differentiation of cells and tissues including the skeleton. Recently, the human osteosarcoma cell line HOS 58 cells were used as an in vitro model of osteoblast differentiation characterized by (i) a rapid proliferation rate in low-density cells that decreased continuously with time of culture and (ii) an increasing secretion of matrix proteins during their in vitro differentiation. In the present paper, HOS 58 cells with low cell density at early time points of the in vitro differentiation (i) displayed a low expression of IGF-I and -II; (ii) synthesized low levels of IGFBP-2, -3, -4, and -5, but (iii) showed high expression levels of both the type I and II IGF receptors. During the in vitro differentiation of HOS 58 cells, IGF-I and -II expressions increased continuously in parallel with an upregulation of IGFBP-2, -3, -4, and -5 whereas the IGF-I receptor and IGF-II/M6P receptor mRNA were downregulated. In conclusion, the high proliferative activity in low cell density HOS 58 cells was associated with high mRNA levels of the IGF-IR, but low concentrations of IGFBP-2. The rate of proliferation of HOS 58 cells continuously decreased during cultivation in parallel with a decline in IGF-IR expression, but increase of mitoinhibitory IGFBP-2. These data are indicative for a role of the IGF axis during the in vitro differentiation of HOS 58 cells.
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PMID:Alteration of the insulin-like growth factor axis during in vitro differentiation of the human osteosarcoma cell line HOS 58. 1737 31