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 synthesis, purification, and characterization of biotinylated analogues of parathyroid hormone (PTH) and PTH-related protein (PTHrP) are described. A novel methodology was developed which allowed the selective biotinylation during solid-phase synthesis of either the Lys13 or Lys26 residue in PTH/PTHrP sequences. Incorporation of orthogonally protected N alpha-Boc-Lys(N epsilon-Fmoc) at a selected position in the sequence, followed by selective side-chain deprotection and biotinylation of the epsilon-amino group, permitted modification of the specific lysine only. Biotinylated analogues of [Nle8,18,Tyr34]bPTH(1-34)NH2 (analogue 1a) were prepared by modification of Lys13 with a biotinyl group (analogue 1) or a biotinyl-epsilon-aminohexanoyl group (analogue 2) or at Lys26 with a biotinyl-epsilon-aminohexanoyl group (analogue 3). A biotinylated PTHrP antagonist [Leu11,D-Trp12,Lys13(N epsilon-(biotinyl-beta-Ala))]PTHrP(7-34)NH2 (analogue 5), was also prepared. In a different synthetic approach, selective modification of the thiol group of [Cys35]PTHrP(1-35)NH2, in solution, with N-biotinyl-N'-(6-maleimidohexanoyl)hydrazide, resulted in analogue 4. The high affinities of the biotinylated analogues for PTH receptors present in human osteosarcoma B-10 cells or in porcine renal cortical membranes (PRCM), were comparable to those of the underivatized parent peptides. The analogues were also highly potent in stimulation of cAMP formation (analogues 1-4) or inhibition of PTH-stimulated adenylyl cyclase (analogue 5) in B-10 cells. The most potent analogue (analogue 1) had potencies in B-10 cells (Kb = 1.5 nM, Km = 0.35 nM) and in porcine renal membranes (Kb = 0.70 nM) identical or similar to those of its parent peptide, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Synthesis of fully active biotinylated analogues of parathyroid hormone and parathyroid hormone-related protein as tools for the characterization of parathyroid hormone receptors. 131 56

PA-III rat prostate adenocarcinoma cells are capable of inducing osteoblastic reaction after inoculation onto rat skeleton. In this study PA-III cells and osteoblast-derived rat osteosarcoma cells (UMR 106 cells) were employed to characterize the cellular interactions in the PA-III cell-induced bone tumors, in vitro. Insulin-like growth factor-I (IGF-I) and conditioned media (CM) of UMR 106 cells stimlated tritiated-thymidine incorporation into the DNA of PA-III cells growing in serum-free media. This effect was inhibited by monoclonal anti-hIGF-I antibody. In addition PA-III cell CM contained proteinolytic activity for the IGF-binding proteins of UMR 106 cell CM (IGFBP-1 and -2). This proteinase activity hydrolyzed also benzyloxycarbonyl-lysine thiobenzyl ester (BLT) and its action on IGFBPs and BLT was inhibited by benzamidine and aprotinin. Proteinase activity of PA-III cell CM when bound covalently to tritiated-dilsopropylfluoro-phosphate (DFP) and then analyzed on SDS-PAGE gel electrophoresis, revealed the presence of radioactivity linked with a 35 kDa protein band. This proteinase was eluted in the void volume of the G-50 sephadex column and was retained on and eluted from p-benzamidine affinity column. The 35 kDa proteinase was retained on and was eluted from cartridges of the C18 silica by 80% acetonitrile over 0.1% trifuroacetic acid. This partially purified material hydrolyzed BLT substrate and IGFBPs of UMR 106 cell CM and its effect was inhibited by benzamidine and aprotinin. These data indicate that PA-III cell CM contains a 35 kDa proteinase capable of digesting the IGFBPs and thus increases the bioavailability of osteoblast-derived IGFs. This mechanism may participate in the pathophysiology of the PA-III cell-induced bone tumor and its subsequent osteoblastic reaction.
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PMID:Proteinolytic activity against IGF-binding proteins involved in the paracrine interactions between prostate adenocarcinoma cells and osteoblasts. 137 96

[Nle8,18,Tyr34]bPTH-(1-34)amide (NlePTH) was biotinylated using sulfosuccinimidyl 6-(biotinamido)hexanoate, in dimethyl sulfoxide, and the multiple resulting peptides peaks were separated by reverse-phase high performance liquid chromatography. Their biological activities were compared with those of NlePTH, the parent compound, in radioreceptor and cAMP accumulation bioassays using rat osteosarcoma 17/2.8 cells; the earliest two eluting products, bioPTH 1 and 2, were equipotent, a third, bioPTH 3, was only 10% as potent, and the remaining, later eluting derivatives all were less than 0.1% as active. Competitive avidin binding assays using [3H]biotin suggested that bioPTH 1 and 2 had a single biotin congener per molecule, while bioPTH 3 contained two biotin residues. Upon Edman degradation, bioPTH 1 contained biotin on the lysine at position 13 of NlePTH; bioPTH 2's biotin was on the lysine at position 26 (or 27) and bioPTH 3 had biotins on lysines at both positions 13 and 26 (or 27). Avidin tagged with 125I, peroxidase, or fluorescein isothiocyanate was detected on bone-derived cells which had been incubated initially with bioPTH 2 (1, 10, and 100 nM) for 4 h, but not when NlePTH (1 microM) was added with bioPTH 2. A fluorescence-activated cell sorter detected a symmetrical shift in fluorescence of bone-derived cells incubated with 10 nM of bioPTH 2 and 10 micrograms/ml fluorescein isothiocyanate-avidin. Addition of a 30-fold molar excess of NlePTH, or omission of bioPTH 2, completely reversed this fluorescence shift, and no shift in fluorescence was seen with cells lacking PTH receptors. This fully active, high affinity biotinylated PTH-derivative should prove useful in the study of PTH receptor-bearing cells.
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PMID:Characterization of fully active biotinylated parathyroid hormone analogs. Application to fluorescence-activated cell sorting of parathyroid hormone receptor bearing cells. 215 27

The concentration in plasma of 15 fasting amino acids were measured in 14 control volunteers and 55 cancer patients. In addition, 16 patients (7 with, 9 without total parenteral nutrition [TPN] ) with metastatic sarcoma had sequential amino acid profiles measured during 6 weeks of ablative chemotherapy. In four cancer patient groups (lymphoma, sarcoma, osteosarcoma and metastatic sarcoma) with no or minimal weight loss, most plasma amino acid levels were similar to controls. Proline levels were significantly reduced in the lymphoma and sarcoma patients. Esophageal cancer patients with 20% body weight loss had a marked reduction in total and individual amino acid levels (except branched chain amino acids) compared to controls and all others. The metastatic sarcoma patients who received parenteral nutrition had higher levels of plasma lysine and tyrosine during chemotherapy than controls; however, TPN failed to change the majority of amino acid levels. It appears that plasma amino acid levels except proline were well maintained in cancer patients without weight loss. Esophageal cancer patients with weight loss demonstrated marked reduction in all circulating amino acids except branched chain. Parenteral nutrition did not significantly alter the amino acid profile of cancer patients undergoing chemotherapy.
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PMID:Fasting plasma amino acid levels in cancer patients. 392 95

Poly I:C/poly-L-lysine (poly ICL) was effective in preventing or delaying the development of osteogenic sarcoma (OGS) in mice. C57BL/6J mice were inoculated subcutaneously with 5 X 10(4) OGS cells and treatment was evaluated by palpable tumor development and subsequent day of death. A significant antitumor effect resulted from injection of 150 microgram of poly ICL into the tumor site starting immediately after tumor implant and followed by four subsequent treatments. Seventy percent of treated animals remained tumor free at 50 days, a time at which 70% of placebo treated animals had died as a result of tumor development. A similar treatment regimen of mice inoculated with 2 X 10(5) OGS cells resulted in a significant delay of time to tumor and subsequent day of death. Treatments with poly ICL were ineffective if they were initiated after development of palpable tumor or if they were administered at a nontumorous site on the animal. These findings indicate that the optimal therapy resulted from repeated intratumor treatment prior to development of extensive tumor burden.
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PMID:Effect of poly I:C/poly-L-lysine (poly ICL) on the development of murine osteogenic sarcoma. 657 30

Plasmin (Pm) is a broad action serine protease implicated in numerous physiological functions. In bone, Pm may play a role in growth, resorption, metastasis, and the activation of growth factors. The various components of the Pm system are known to bind and function on the cell surface of various cell types, but no pertinent data are available describing membrane-bound Pm or its zymogen, plasminogen (Pg), in either normal or neoplastic bone cells. We report here that Pg binds to the surface of the human osteosarcoma cell line MG-63 and is activated to Pm by endogenous urokinase plasminogen activator (uPA). These conclusions are based on experiments utilizing radiolabeled compounds and a cell surface proteolytic assay measuring amidolytic activity of Pm. 125I-Pg binding to cells was time dependent, saturable, reversible, and specific. Binding was characterized by a relatively low affinity (Kd approximately 0.9 microM) and a high capacity (approximately 7.5 x 10(6) sites/cell). The binding of 125I-Pg was associated with lysine binding sites of the plasminogen molecule. Activation of 125I-Pg to 125I-Pm occurred on the cell surface and was dependent upon cell bound uPA, as determined by inhibitory antibodies. Binding of Pg to MG-63 monolayers represented approximately 80% bound specifically to the cell surface and the remainder to the surrounding extra-cellular matrix. Either co-incubation with uPA or pre-incubation with Pm resulted in increased 125I-Pg binding to osteosarcoma cells. Cell surface Pm proteolytic activity was confirmed by an amidolytic chromogenic assay. Both Pm and Pg bound to cells with Pg being activated by endogenous uPA. Plasmin activated on the cell surface was partially protected from inhibition by alpha 2-antiPm (requiring Pm lysine binding site interaction) but inhibited by aprotinin, (interacting directly with the Pm catalytic site). Resistance of cell bound Pm to alpha 2-antiPm inhibition suggests that cell surface proteolysis can occur in the presence of a soluble Pm inhibitor known to exist in the extracellular space. Based on these results, we speculate that the various bone physiological processes implicating Pm may occur at or near the bone cell surface.
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PMID:Binding and activation of plasminogen on the surface of osteosarcoma cells. 751 Nov 44

beta-Cystathionase (EC 4.4.1.8) from Bordetella avium is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the hydrolysis of L-cystine to yield pyruvic acid, NH3, and thiocysteine. The latter compound is highly toxic toward MC3T3-E1 osteogenic cells, rat osteosarcoma cells, and other cell lines maintained in tissue culture (Gentry-Weeks, C. R., Keith, J. M., and Thompson, J. (1993) J. Biol. Chem. 268, 7298-7314). Site-directed mutagenesis has established that lysine 214 of the sequence TKYVGGHSD, is primarily responsible for internal aldimine binding of PLP in the holoenzyme. Translation of the DNA sequence of the beta-cystathionase gene (metC) from B. avium, reveals 4 cysteine residues/enzyme subunit (M(r) = 42,600), and spectrophotometric analysis with 4,4'-dithiodipyridine showed that there were no disulfide linkages in the native protein. beta-Cystathionase is inhibited by sulfhydryl-reactive agents, including N-ethylmaleimide (NEM). To elucidate the mechanism of NEM inhibition, each of the 4 cysteine residues at positions 88, 117, 279, and 309 was individually replaced by alanine or glycine. The mutant proteins C88A, C117G, C279G, and C309A were purified to homogeneity, and each was assayed for enzyme activity, PLP-binding, NEM sensitivity, and susceptibility to chymotrypsin digestion. The activities of mutant proteins C88A and C279G were comparable with that of the native enzyme, and since both forms were inhibited by NEM, neither cysteine 88 nor 279 are prerequisite for enzyme activity. By elimination, cysteine residues 117 and 309 must be the targets for alkylation, and resultant inactivation of beta-cystathionase, by the -SH reactive agent. Substitution of cysteine 117 and 309 with glycine and alanine, respectively, yielded the inactive proteins C117G and C309A. PLP was not detectable in these proteins, and their absorption spectra lacked the peak (at 420 nm) that is characteristic of internal PLP-Schiff base formation. Edman degradation revealed that C117G (M(r) approximately 36,000) also lacked the first 63 amino acids comprising the N terminus of the native protein. The beta-cystathionase mutants C117G and C309A showed enhanced susceptibility to chymotrypsin digestion. Cysteine residues 117 and 309 may reside in conformationally sensitive environments, and in the native enzyme these amino acids most probably serve a structural function. Toxicity assays performed with the various mutant proteins obtained by site-directed mutagenesis established that only catalytically active forms of beta-cystathionase were were cytotoxic for tissue culture cells.
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PMID:beta-Cystathionase from Bordetella avium. Role(s) of lysine 214 and cysteine residues in activity and cytotoxicity. 770 18

The promotive effects of poly-cations on immunoglobulin production was investigated using human-human hybridoma cells. Among poly-cations tested, epsilon-poly-L-lysine with hydrochloride (approximately 4 kDa), which has been used as an antibacterial food additive, had the greatest activity in enhancing IgM production of human-human hybridoma HB4C5 cells without stimulating cell proliferation. Immunoglobulin production stimulatory (IPS) activity of epsilon-poly-lysine was not affected by trypsin digestion. It was stable below 60 degrees C but completely inactivated with heating at 100 degrees C for 30 min. epsilon-Poly-lysine also enhanced interferon-beta (IFN-beta) production of human osteosarcoma MG-63 cells, but this stimulatory effect was reduced by the trypsin digestion.
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PMID:Enhancement of production of IgM and interferon-beta in human cell lines by poly-lysine. 853 72

Monoclonal antibodies TP-1 and TP-3 are of potential utility for the radioimmunodiagnosis of osteosarcoma in both human and canine patients. The V genes of these antibodies were cloned and sequenced and to facilitate radiolabeling of these proteins, the location of the lysine residues within these sequences have been determined. The V-domains of TP-1 contain a total of 12 lysines, 10 in the framework region and 2 in the CDR region, while the V-domains of TP-3 contain a total of 14 lysines, 11 in the framework region and 3 in the CDR regions. Using space-filling models, the availability of each lysine residue for radiolabeling, and potential interference with antigen binding was predicted.
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PMID:Cloning and sequencing of V genes from anti-osteosarcoma monoclonal antibodies TP-1 and TP-3: location of lysine residues and implications for radiolabeling. 853 37

Immunoscintigraphy is a tumour imaging technique that can have specificity, but high background radioactivity makes it difficult to obtain tumour imaging soon after the injection of radioconjugate. The aim of this study is to see whether clear tumour images can be obtained soon after injection of a radiolabelled reagent using a new linker with antibody fragments (Fab), in conditions of induced hypertension in mice. Fab fragments of a murine monoclonal antibody against human osteosarcoma were labelled with radioiodinated 3'-iodohippuryl N-epsilon-maleoyl-L-lysine (HML) and were injected intravenously to tumour-bearing mice. Angiotensin II was administered for 4 h before and for 1 h after the injection of radiolabelled Fab. Kidney uptake of 125I-labelled-HML-Fab was much lower than that of 125I-labelled-Fab radioiodinated by the chloramine-T method, and the radioactivity of tumour was increased approximately two-fold by angiotensin II treatment at 3 h after injection, indicating high tumour-to-normal tissue ratios. A clear tumour image was obtained with 131I-labelled-HML-Fab at 3 h post-injection. The use of HML as a radiolabelling reagent, combined with angiotensin II treatment, efficiently improved tumour targeting and enabled the imaging of tumours. These results suggest the feasibility of PET scan using antibody fragment labelled with 18F-fluorine substitute for radioiodine.
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PMID:A novel immunoscintigraphy technique using metabolizable linker with angiotensin II treatment. 1020 95


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