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)

Dentin sialoprotein (DSP) is a 53-kDa protein isolated from rat dentin. It contains 29.6% carbohydrate (including 9% sialic acid) and has an overall composition similar to that of the bone sialoproteins osteopontin and bone sialoprotein (i.e. rich in Asp, Ser, Glu, and Gly). Using a monospecific anti-DSP polyclonal antibody to screen a rat incisor odontoblast cDNA library, a cDNA clone was isolated and sequenced. This approximately 750-base pair clone contained a DNA sequence corresponding to the NH2-terminal 9 amino acids of DSP. A second cDNA clone was isolated by using the first cDNA as a probe to rescreen the library. This second clone had the full-length DSP coding region. From the sequence, we deduced that the DSP cDNA coded for 366 amino acids, predominantly Asp, Ser, Glu, and Gly. The amino acid composition calculated for this sequence was very similar to that for purified DSP reported earlier; likewise the deduced molecular weight (53,045) was essentially identical to that determined by sedimentation equilibrium. Six potential N-linked glycosylation sites were present in the predicted DSP sequence. No Arg-Gly-Asp sequence was found, and the sequence for DSP was dissimilar to those of osteopontin and bone sialoprotein. Multiple transcripts near 4.6 and 1.5 kilobases were detected by Northern blot analysis in the incisor of 21-day-old rat and the tooth germ of the newborn rat. Consistent with previous immunohistochemical findings, no transcripts were detected in brain, salivary gland, heart, muscle, spleen, kidney, intestine, lung, liver, pancreas, tibia, calvaria, or osteoblast-like osteosarcoma (ROS 17/2.8) cells, indicating that DSP is specifically expressed by odontoblasts and related cells.
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PMID:Cloning and sequence determination of rat dentin sialoprotein, a novel dentin protein. 810 14

Tumor cells are capable of simultaneously producing a number of related inflammatory peptides, now classified as chemokines. We have isolated a new human granulocyte chemotactic protein (GCP-2), coproduced with interleukin-8 (GCP-1/IL-8) by osteosarcoma cells. Furthermore, the bovine homologue of human GCP-2 was purified from kidney tumor cells using the same isolation procedure. Both chemokines occur in at least four NH2-terminally truncated forms. These 5-6 kDa proteins do not differ in potency and efficacy as granulocyte chemotactic factors using a standard in vitro migration assay. The complete primary structures of human and bovine GCP-2 were disclosed by sequencing peptide fragments derived from the natural proteins. On the basis of the conservation of four cysteine residues, the two molecules are to be classified within the C-X-C chemokine family, including IL-8. Human and bovine GCP-2 are 67% similar at the amino acid level. Their sequences show only weak similarity with that of IL-8, and human GCP-2 does not cross-react in a radioimmunoassay for IL-8. Human and bovine GCP-2 are specific granulocyte chemotactic factors in that they do not attract human monocytes. Bovine GCP-2 is not species specific since it is at least as active as human GCP-2 on human granulocytes. Both chemokines can also activate postreceptor mechanisms leading to release of gelatinase B by granulocytes. This is indicative for a possible role in inflammation and tumor cell invasion.
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PMID:Human and bovine granulocyte chemotactic protein-2: complete amino acid sequence and functional characterization as chemokines. 839 43

Bordetella avium is the etiological agent of an upper respiratory disease in birds which, symptomatically and pathologically, resembles bordetellosis in humans. Studies of the virulence of this organism revealed a novel cytotoxic protein, designated osteotoxin, that was lethal for MC3T3-E1 osteogenic cells, fetal bovine trabecular cells, UMR106-01(BSP) rat osteosarcoma cells, and embryonic bovine tracheal cells. The osteotoxin lacked dermonecrotic toxin activity, exhibited no cross-reactivity with antibody against B. avium dermonecrotic toxin, and was non-proteolytic. Osteotoxin (M(r) approximately 80,000 by gel filtration, pI 5.4) was purified to electrophoretic homogeneity from B. avium 197. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and spectrophotometric analyses showed that the native protein was a homodimer and that each of the non-covalently linked subunits (M(r) approximately 41,000) contained one molecule of pyridoxal 5'-phosphate. Microsequencing of the first 32 amino acids from the NH2 terminus allowed the synthesis of two oligonucleotide probes, which, together with polyclonal antibody to the purified protein, facilitated cloning, sequencing, and expression of the osteotoxin gene product in Escherichia coli. The open reading frame encodes a polypeptide of 396 amino acid residues (M(r) = 42,606, calculated pI 5.9), whose sequence exhibits approximately 38% identity (approximately 60% similarity) to pyridoxal 5'-phosphate-dependent beta-cystathionase(s) from E. coli, Salmonella typhimurium, and rat liver. The characteristic motif, TKYXXGHSD, associated with binding the cofactor in these enzymes is also present in osteotoxin. Physicochemical and enzymatic analyses established the coidentity of osteotoxin with beta-cystathionase. The region upstream of the beta-cystathionase (metC) gene in B. avium 197 lacked regulatory sequences ("Met boxes") described for metC in enteric species, and enzyme production was not repressed by methionine. Incubation of MC3T3-E1 osteogenic cells in medium containing L-[35S]cystine and purified beta-cystathionase resulted in 35S-labeling of the enzyme and at least one major MC3T3-E1 cell protein (M(r) approximately 50,000). cytotoxicity can be attributed to: 1) beta-cystathionase-catalyzed cleavage of L-cystine in the medium and formation of reactive sulfane-containing derivative(s), and 2) transfer of sulfane sulfur to metabolically sensitive or structurally important proteins in the osteogenic cells.
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PMID:Toxicity of Bordetella avium beta-cystathionase toward MC3T3-E1 osteogenic cells. 846 65

A midregion fragment of PTH-related protein (PTHrP), which is intensively conserved across species, has been identified as a secretory product of several different cell types, including keratinocytes and squamous carcinomas. As recent data suggest that a midregion PTHrP fragment may be biologically active, we hypothesized that midregion PTHrPs interact with unique cell surface receptors that mediate autocrine or paracrine action. Dose-dependent transient elevations in intracellular calcium ([Ca2-]i) were observed in fura-2-loaded SqCC/Y1 squamous carcinoma cells exposed to human (h) PTHrP-(67-86)NH2, [Tyr36]hPTHrP-(1-36)NH2, and hPTHrP-(1-141) at concentrations ranging from 1 pM to 1 microM. The effects of maximal stimulatory concentrations of [Tyr36]PTHrP-(1-36)NH2 and PTHrP-(67-86)NH2 on [Ca2+]i were additive. The inhibitory PTH analog, [D-Trp12,Tyr34]bovine PTH-(7-34)NH2, attenuated the [Ca2+]i response to [Tyr36]hPTHrP-(1-36)NH2, but not that to PTHrP-(67-86)NH2. These data suggest that PTHrP-(67-86)NH2 activates a different receptor pathway in SqCC/Y1 cells from the one activated by [Tyr36]hPTHrP-(1-36)NH2. Radiolabeled PTHrP-(67-86)NH2 did not bind to SqCC/Y1 cells, and PTHrP-(67-86)NH2 did not compete for binding of 125I-labeled [Tyr36]PTHrP-(1-36)NH2 to PTH/PTHrP receptors on SaOS-2 osteosarcoma cells. Activation of the phospholipase C pathway by PTHrP-(67-86)NH2 was confirmed by exposing SqCC/Y1 cells to peptide for 1 min and measuring the accumulation of inositol trisphosphates. PTHrP-(67-86)NH2 treatment (100 nM) resulted in maximal stimulation of inositol trisphosphates of 3.1 +/- 0.1-fold over the control value, with an EC50 of 1.5 +/- 1.2 nm. In contrast, PTHrP-(67-86)NH2 (0.1 nM to 1 microM) did not stimulate adenylyl cyclase in SqCC/Y1 cells despite vigorous stimulation of cAMP formation by isoproterenol (1 microM) to 66-fold over the basal value. To determine whether messenger RNA (mRNA) prepared from SqCC/Y1 cells would direct the translation of a receptor protein that mediated a [Ca2+]i response to PTHrP-(67-86)NH2, we performed expression studies in Xenopus oocytes. Fluo-3 fluorescence in Xenopus oocytes expressing SqCC/Y1 mRNA was visualized by confocal video microscopy after exposure to 1 microM PTHrP-(67-86)NH2. Clear increases in [Ca2+]i were detected in mRNA-injected, but not in sham-injected, oocytes. Finally, we examined the effect of PTHrP-(67-86)NH2 treatment on fibronectin secretion from SqCC/YN1 cells. A significant 3.5-fold increase in fibronectin secretion into conditioned medium was observed when SqCC/Y1 cells were exposed to 100 nM PTHrP-(67-86)NH2, and this effect was dose dependent, with an EC50 of 0.1 nM. We conclude that PTHrP-(67-86)NH2 activates phospholipase C-dependent pathways in SqCC/Y1 cells through a receptor distinct from that activated by PTHrP-(1-36) in the same cells. As a midregion secretory fragment of PTHrP has been partially purified from several different cell types, this receptor may have broad biological significance.
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PMID:A midregion parathyroid hormone-related peptide mobilizes cytosolic calcium and stimulates formation of inositol trisphosphate in a squamous carcinoma cell line. 894 Mar 60

The C-terminal region of parathyroid hormone-related protein (PTHrP) containing the sequence (107-111) appears to be a potent inhibitor of osteoclastic bone resorption. In the present study, we have investigated the effect of human (h)PTHrP (107-139) and hPTHrP (107-111)NH2 on the proliferation of osteoblastic rat osteosarcoma UMR 106 cells. We found that both C-terminal PTHrP peptides, like hPTHrP (1-141), were antimitogenic for these cells, between 1 pM and 10 nM. [Tyr34]hPTHrP (1-34)NH2 was as potent as these peptides but less effective as growth inhibitor in these cells. UMR 106 cells were found to produce and secrete immunoreactive PTHrP. Addition of anti-PTHrP neutralizing antibodies to C- and N-terminal epitopes of PTHrP increased the growth of these cells. Our data suggest that the antiproliferative effect of these C-terminal PTHrP analogs may be independent of cyclic adenosine 3':5'-monophosphate (cAMP) and mediated by protein kinase C. These findings support an autocrine role of PTHrP in bone metabolism.
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PMID:Antiproliferative effect of the C-terminal fragments of parathyroid hormone-related protein, PTHrP-(107-111) and (107-139), on osteoblastic osteosarcoma cells. 900 50

In a search for analogues of human parathyroid hormone (hPTH) with improved activities and bioavailabilities, we have prepared the following three lactam analogues of hPTH-(1-31)-NH2 (1) or [Leu27]hPTH-(1-31)-NH2 (2): [Leu27]cyclo(Glu22-Lys26)-hPTH-(1-31)-NH2 (3), [Leu27]cyclo(Lys26-Asp30)-hPTH-(1-31)-NH2 (4), and cyclo(Lys27-Asp30)-hPTH-(1-31)-NH2 (5). Analogues 1, 2, and 5 had seven or eight residues of alpha-helix, as estimated from their circular dichroism (CD) spectra, in contrast to 12 residues in cyclic analogues 3 and 4. Thus, lactams 3 and 4 stabilized a helix previously shown to exist within residues 17-29. The adenylyl cyclase activity (EC50), measured in rat osteosarcoma 17/2 cells, of 5 (40.3 +/- 2.3 nM) was half that of its linear form 1 (19.9 +/- 3.9 nM). The linear Leu27 mutant 2 was twice as active (11.5 +/- 5.2) as analogue 1, and lactam analogue 3 was 6-fold more active (3.3 +/- 0.3 nM). Lactam analogue 4 had less activity (16.9 +/- 3.3 nM) than 2, its linear form. Peptides hPTH-(1-30)-NH2 (6), [Leu27]hPTH-(1-30)-NH2 (7), and [Leu27]cyclo(Glu22-Lys26)-hPTH-(1-30)-NH2 (8) all had AC-stimulating activities similar to that of 1. When injected intravenously, with a dose of 0.8 nmol/100 g of analogue in acid saline, hypotensive effects paralleled their adenylyl cyclase activities. They behaved quite differently when applied subcutaneously. Analogues 1, 5, and 6, the weakest, showed about half the drop in blood pressure observed with 3 and 4, the most active. In contrast, the time required to reach a maximum drop in blood pressure of 4-8, after subcutaneous administration, was 2-4 times that of the other analogues. Thus, the bioavailabilities of the lactam analogues, unlike their adenylyl cyclase-stimulating activities, were highly dependent on the presence or conformation of Val31.
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PMID:Bioactivities and secondary structures of constrained analogues of human parathyroid hormone: cyclic lactams of the receptor binding region. 913 34

Human parathyroid hormone (hPTH)-(1-31)NH2 (Ostabolin), which only stimulates adenylyl cyclase (AC) instead of AC and phospholipase-C as do hPTH(1-84) and hPTH(1-34), strongly stimulates femoral cortical and trabecular bone growth in ovariectomized (OVX) rats. Two side-chain lactams have been introduced in the hydrophilic face of the receptor-binding region of the fragment's Ser17-Val31 amphiphilic alpha-helix in an attempt to develop improved analogs for the treatment of osteoporosis. Replacing the polar Lys27 with an apolar Leu on the hydrophobic face of this alpha-helix and stabilizing the helix with a lactam between Glu22 and Lys26 produced a fragment, [Leu27]-cyclo(Glu22-Lys26)-hPTH(1-31)NH2, which had six times the AC-stimulating ability of hPTH(1-31)NH2 in ROS 17/2 rat osteosarcoma cells, but the other helix-stabilizing lactam derivative [Leu27]-cyclo(Lys26-Arg30)-hPTH(1-31)NH2 did not have a greater AC-stimulating ability than hPTH(1-31)NH2, to stimulate AC in ROS 17/2 rat osteosarcoma cells. As expected from AC stimulation being responsible for PTH's anabolic action, [Leu27]-cyclo(Glu22-Lys26)-hPTH(1-31)NH2 was, depending on the experimental design, a 1.4 to 2 times better stimulator of trabecular bone growth in the OVX rat model than either hPTH(1-31)NH2 or [Leu27]-cyclo(Lys26-Arg30)-hPTH(1-31)NH2. Thus, there is now a more potently anabolic derivative of hPTH(1-31)NH2, [Leu27]-cyclo(Glu22-Lys26)-hPTH(1-31)NH2, which might ultimately prove to be one of the more effective therapeutics for osteoporosis.
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PMID:Cyclization by a specific lactam increases the ability of human parathyroid hormone (hPTH)-(1-31)NH2 to stimulate bone growth in ovariectomized rats. 925 55

N-terminal fragments of PTH and PTHrP, such as hPTH-(1-34) and hPTHrP-(1-34), are sufficiently similar with respect to amino acid sequence, location of functional domains, and higher order configuration to activate the same PTH/PTHrP receptor and the same two signal enzymes, adenylyl cyclase and phospholipase-Cbeta. Therefore, it was expected that hPTHrP-(1-31)NH2 would stimulate bone growth in ovariectomized rats as strongly as hPTH-(1-31)NH2. Like hPTH-(1-31)NH2, hPTHrP-(1-31)NH2 stimulated adenyly cyclase in ROS 17/2 osteosarcoma cells as strongly as the standard hPTH-(1-34) and like hPTH-(1-31)NH2, triggered a large drop in mean blood pressure when injected intravenously. Unlike hPTH-(1-31)NH2, however, hPTHrP-(1-31)NH2 could not stimulate trabecular growth in the distal femurs of young, sexually mature, ovariectomized rats.
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PMID:Comparison of the abilities of human parathyroid hormone(1-31)NH2 and human parathyroid hormone-related protein(1-31)NH2 to stimulate femoral trabecular bone growth in ovariectomized rats. 931 3

Chemokines contribute to the inflammatory response by selective attraction of various leukocytic cell types. Human GCP-2 was originally identified by amino acid sequence analysis as a CXC chemokine co-produced with IL-8 by osteosarcoma cells. Furthermore, the complete coding domain of human GCP-2 was disclosed by means of RT-PCR. Similarly, mouse GCP-2 was isolated from fibroblastoid and epithelial cells and completely identified by sequence analysis. Human and mouse GCP-2 share 61% identical amino acids. Both chemokines occur as multiple NH2-terminally truncated forms. The shorter forms of mouse, but not those of human, GCP-2 showed a higher neutrophil chemotactic potency and gelatinase B releasing capacity. Mouse GCP-2 was a more potent neutrophil activator than human GCP-2, natural mouse KC, and MIP-2. Human GCP-2 was not chemotactic for monocytes, lymphocytes, or eosinophils. Quantitative studies of mRNA expression in diploid fibroblasts revealed GCP-2 induction by IL-1beta. Human GCP-2 induced [Ca2+]i increase in neutrophils, which was reciprocally desensitized by IL-8, GROalpha, and ENA-78. Human GCP-2 induced [Ca2+]i increases and chemotactic responses in both CXCR1- and CXCR2-transfected cells. Finally, GCP-2 provoked neutrophil accumulation and plasma extravasation in rabbit skin. In humans, GCP-2 complements the activity of IL-8 as neutrophil chemoattractant and activator but it constitutes a major neutrophil chemokine in the mouse. GCP-2 induces neutrophil chemotaxis and activation but it might also contribute to detrimental tissue damage in sepsis, acute respiratory distress syndrome, acute hypersensitivity reactions, and autoimmune diseases. It might also influence the invasive capacity of GCP-2-secreting tumor cells.
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PMID:Granulocyte chemotactic protein-2 and related CXC chemokines: from gene regulation to receptor usage. 936 9

CCR5, a chemokine receptor expressed on T cells and macrophages, is the principal coreceptor for M-tropic HIV-1 strains. Recently, we described an NH2-terminal modification of the CCR5 ligand regulated on activation, normal T cell expressed and secreted (RANTES), aminooxypentane-RANTES (AOP-RANTES), that showed potent inhibition of macrophage infection by HIV-1 under conditions where RANTES was barely effective. To investigate the mechanism of AOP-RANTES inhibition of HIV infectivity we examined the surface expression of CCR5 using a monoclonal anti-CCR5 antibody, MC-1. We demonstrate that AOP-RANTES rapidly caused >90% decrease in cell surface expression of CCR5 on lymphocytes, monocytes/ macrophages, and CCR5 transfected Chinese hamster ovary (CHO) cells. RANTES also caused a loss of cell surface CCR5, although its effect was less than with AOP-RANTES. Significantly, AOP-RANTES inhibited recycling of internalized CCR5 to the cell surface, whereas RANTES did not. When peripheral blood mononuclear cells are cultured for prolonged periods of time in the presence of RANTES, CCR5 expression is comparable to that seen on cells treated with control medium, whereas there is no CCR5 surface expression on cells cultured in the presence of AOP-RANTES. Immunofluorescence indicated that both AOP-RANTES and RANTES induced downmodulation of cell surface CCR5, and that the receptor was redistributed into endocytic organelles containing the transferrin receptor. When RANTES was removed, the internalized receptor was recycled to the cell surface; however, the receptor internalized in the presence of AOP-RANTES was retained in endosomes. Using human osteosarcoma (GHOST) 34/CCR5 cells, the potency of AOP-RANTES and RANTES to inhibit infection by the M-tropic HIV-1 strain, SF 162, correlated with the degree of downregulation of CCR5 induced by the two chemokines. These differences between AOP-RANTES and RANTES in their effect on receptor downregulation and recycling suggest a mechanism for the potent inhibition of HIV infection by AOP-RANTES. Moreover, these results support the notion that receptor internalization and inhibition of receptor recycling present new targets for therapeutic agents to prevent HIV infection.
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PMID:Aminooxypentane-RANTES induces CCR5 internalization but inhibits recycling: a novel inhibitory mechanism of HIV infectivity. 954 33


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