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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Salt and detergent extracts of a malignant epithelial tumor, obtained by extraction of acetone powder, were fractionated on different sets of Sepharose columns covalently derivatized with lactose, asialofetuin, melibiose, mannan, fucose, and heparin. Successive elution by chelating reagent and specific sugar resulted in isolation of different Ca2+-dependent and Ca2+-independent endogenous carbohydrate-binding proteins, as analyzed by gel electrophoresis. It appears from the analysis that certain bands represent newly identified proteins capable of binding to lactose (at Mr 64,000), melibiose (at Mr 28,000), and fucose (at Mr 62,000 and 70,000). Other carbohydrate-binding proteins isolated from this human tumor have been identified in normal, especially embryonic, tissues of different nonhuman vertebrates. The carbohydrate-binding proteins are assayable as agglutinin with rabbit erythrocytes and show no detectable enzymatic activity. They can thus be defined as lectins. The presence of a complex pattern of endogenous lectins and their biochemical characteristics may contribute to an understanding of intercellular interaction during the complex process of metastatic spread and may furthermore allow a new tool for diagnosis and a lectin-based therapy.
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PMID:Pattern of endogenous lectins in a human epithelial tumor. 396 38

We have studied the potential use of immunotoxins (ITs) for therapeutic treatment of human tumors in an experimental model of human neoplasia. We tested intact ricin IT for its antitumor activity against established tumors. CEM, a human T-cell leukemia line expressing an Mr 67,000 cell surface antigen, and Daudi, a human B-cell lymphoma line which does not express the antigen, were found to be consistently tumorigenic in nude mice. ITs were synthesized using T101, a high-affinity monoclonal antibody reacting with the Mr 67,000 protein determinant and intact ricin. We have shown for the first time that established CEM solid tumors in nude mice will regress following intratumoral injection of T101-ricin IT, while Daudi tumors will not. Selective activity of T101-ricin is dependent on systemic i.v. administration of lactose and local intratumoral injection of the T101-ricin IT with lactose. Intact ricin ITs require the presence of lactose to block native ricin binding and render them antigen specific when linked to monoclonal antibody. Killing of target was cell specific since (a) nonspecific (irrelevant) ITs did not cause the regression of CEM tumors, and (b) injection of large amounts of free T101 antibody prior to T101-ricin IT blocked antitumor activity. Selectivity was not absolute, since regression occurred in one of six animals given irrelevant IT, and blocking was observed in two of four mice. Intratumoral IT treatment with 1 or 2 micrograms of T101-ricin IT plus lactose was not harmful to mice in contrast to intratumoral ricin treatment, which killed all treated tumor-bearing mice at a dose of 0.3 micrograms. Without i.v. injection of lactose, intratumoral injection of T101-ricin IT was also effective in eliminating established tumors. However, this treatment did not result in the selective elimination of tumor, since Daudi tumors also regressed following T101-ricin IT treatment. IT, made with ricin A chain only (T101-A chain IT), was also tested against established CEM tumors. We found that high dosages of T101-A chain IT did not destroy CEM tumors when injected intratumorally, even in the presence of activating agents such as NH4Cl or the carboxylic ionophore X-537 A. In contrast, in vitro experiments demonstrated that T101-A chain IT plus activating agents had potent and selective cytotoxic effect against CEM cells. We conclude that ITs are specifically toxic to established tumors. Although selectivity is not absolute, ITs exhibit potential as a new class of antitumor reagents.
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PMID:Cytotoxic effect of anti-Mr 67,000 protein immunotoxins on human tumors in a nude mouse model. 397 76

Adrenal medullary hyperplasia and neoplasia occur both enzootically and epizootically in untreated laboratory rats. The lesions are typically chromaffin-negative and are found incidentally in animals that have died from unrelated causes or have been killed at the end of long-term toxicity/carcinogenicity tests. Urinary excretion of catecholamines is not usually increased. Environmental, particularly dietary, factors are seemingly much more important than genetic ones as determinants of the incidence of proliferative lesions. Recent observations of enhancement of adrenal medullary proliferative disease in rats by the feeding, in high dietary concentration, of certain polyols (sorbitol, mannitol, xylitol, lactitol), or of lactose, suggested that increased absorption of calcium from the gastrointestinal tract may be a risk factor. This evidence is reported and discussed in the light of other evidence linking disturbed calcium homeostasis with adrenal medullary function in the rat. In man, adrenal medullary proliferative disease is relatively rare and there is no evidence of any relation between the hypercalcaemia associated with hyperparathyroidism and increased risk of phaeochromocytoma. Adrenal medullary proliferative disease in rats is usually seen against a background of multiple endocrine neoplasia, with the pituitary gland, the pancreatic islets and the thyroid C-cells being most commonly affected in addition to the adrenal medulla. A parallel between this situation and Sipple's disease in humans has previously been suggested. We now stress the possible importance of three factors as determinants of enzootic and epizootic adrenal medullary proliferative disease in rats: excessive food intake, excessive dietary levels of calcium and phosphate and excessive intake of other food components, such as vitamin D and poorly absorbable carbohydrates, which predispose to increased calcium absorption.
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PMID:Enzootic and epizootic adrenal medullary proliferative disease of rats: influence of dietary factors which affect calcium absorption. 398 3

Three clones of myeloproliferative virus (MPV)-transformed rat fibroblasts (NRK) with different growth properties and morphology were transplanted to athymic nude mice. Presence of carbohydrate-binding proteins was inferred by fluorescence microscopy using fluorescent, glycosylated markers. Salt and detergent extracts of tumors from this model system were fractionated under identical conditions on different sets of Sepharose columns, to which lactose, asialofetuin, melibiose, mannan and fucose had been covalently linked. Successive elution by chelating reagent and specific sugar resulted in isolation of the different Ca2+ -dependent and Ca2+ -independent endogenous carbohydrate-binding proteins that were assayable as agglutinins. In comparison, the different tumors displayed a pattern with qualitative and quantitative alterations. Since protein-carbohydrate interaction mediated by carbohydrate-binding proteins (lectins) is of importance for cognitive processes, it is remarkable that the pattern of membrane glycoproteins, isolated by affinity chromatography on resins with immobilized plant lectins, had also been found to reveal certain individual properties for receptors specific for peanut agglutinin (PNA) and Ulex europaeus agglutinin (UEA). These demonstrated differences within the system of protein-carbohydrate interaction suggest that endogenous lectins and their ligands have potential significance as markers defining a certain phenotype within this tumor model system.
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PMID:Carbohydrate-binding proteins of tumor lines with different growth properties. I. Differences in their pattern for three clones of rat fibroblasts transformed with a myeloproliferative sarcoma virus. 402 24

Fractionation of detergent extracts of transplanted tumors of human teratocarcinoma cells by affinity chromatography yields one predominant protein with apparent molecular weight of 14,000 and further, for less abundant protein with apparent molecular weight of 35,000 from lactose-sepharose and one protein with apparent molecular weight of 68,000 from mannan-sepharose. No further carbohydrate-binding protein can be isolated on columns derivatized with asialofetuin, melibiose and L-fucose, to which the extract is applied successively. Both proteins agglutinate trypsinized, glutaraldehyde-fixed rabbit erythrocytes in the absence of Ca2+ and can thus be defined as endogenous human teratocarcinoma lectins. Inhibition of heterotypic and homotypic aggregation of human teratocarcinoma cells by D-mannose, D-galactose and glycoproteins rich in one of these sugars is consistent with a functional role of these Ca2+-independent lectins in cell aggregation. Visualization of these activities by fluorescent mannosylated and lactosylated markers on the cell surface further supports the cell surface localization of these detergent extractable lectins. The mannan-specific lectin, in particular, has so far not been detected in any mammalian tissue or tumor and is of potential value for a lectin-based diagnosis and therapy of embryonal carcinomas.
Tumour Biol 1985
PMID:Cell surface lectins of transplantable human teratocarcinoma cells: purification of a new mannan-specific endogenous lectin. 404 75

A 7 year study of megestrol and chlormadinone in female dogs is in progress. This report characterized histopathologically 60 mammary nodules during the first 4 years of the study. 100 purebred female beagles, 6-12 months of age, were randomly assigned to 5 equal groups. One group was used as a control. Oral doses were .01, .10, and .25 mg/kg/day of megestrol acetate in coconut oil in capsules and of chlormadinone acetate .25 mg/kg/day in lactose tablets. These doses were 1, 10, and 25 times the projected dose of megestrol for humans and about 25 times the human dose of chlormadinone. After 2 years 4 dogs from each group were necropsied. One high-dose megestrol-treated and 1 chlormadinone-treated dog had benign mixed mammary tumors. Palpable nodules were first observed at 16 months in the chlormadinone-treated dogs, at 18 months in dogs given the high dose megestrol and at 27 months in the dogs treated with middle-dose megestrol. Transitory nodules were found in 4 control dogs after 21 months and in low dose megestrol-treated dogs at 26 months. Of 38 grossly detected nodules evaluated microscopically from the megestrol-treated dogs 27 were nodular hyperplasia, 5 were benign mixed mammary tumors, 3 were ductal dialatations, 1 was a lymph node, 1 was fat necrosis and 1 was the umbilicus. Of 22 nodules from the chlormadinone-treated dogs 12 were nodular hyperplasia, 4 benign mixed mammary tumors, 1 chondromucoid degeneration and 1 adenocarcinoma with widespread metastases. 3 nodules were lymph nodes and 1 other had no mammary tissue. Involutions, regression and sclerosis of many areas of nodular hyperplasia were evident at 4 years. Thus of the 60 nodules evaluated during the first 4 years of the study 50 were non-neoplastic and 10 were neoplastic. It is considered that the 1 adenocarcinoma may have been spontaneous and not a treatment-related neoplasm. A precursor stage through nodular hyperplasia apparently did not occur.
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PMID:Mammary nodules in dogs during four years' treatment with megestrol acetate or chlormadinone acetate. 412 57

Single-cell suspensions of several tumor cell lines, including five human melanomas (A375, SH4, Hs294, Hs852, and Hs939), a human cervical adenocarcinoma (HeLa-S3), a murine melanoma (B16-F1), and a murine fibrosarcoma (UV-2237P), undergo extensive homotypic aggregation in the presence of the glycoproteins fetuin and its desialated derivative, asialofetuin. This phenomenon was observed even at very low glycoprotein concentrations (less than 10 micrograms/ml). Fluorescent derivatives of fetuin and asialofetuin bind to the surface B16-F1 melanoma cells; this binding can be inhibited by lactose (0.1 M). Since the above results suggested the presence of a carbohydrate-binding component(s) on the tumor cells, we tested the possibility that the cells contain endogenous lectin(s). Extracts prepared from the neoplastic cell lines used in this study exhibited a potent capacity to agglutinate trypsin-treated, glutaraldehyde-fixed rabbit erythrocytes. This activity was abolished by treating the extracts with trypsin and could be inhibited by millimolar concentrations of lactose, whereas D-galactose, D-galactosamine, and N-acetyl-D-galactosamine were much less potent inhibitors. D-Mannose, L-fucose, and N-acetyl-D-glucosamine failed to inhibit hemagglutination at 0.2 M. These results demonstrate the presence of a galactoside-specific lectin in the tumor cells. The implications of the existence of a carbohydrate-binding protein(s) on the surface of malignant cells on their in vivo behavior, especially as it may relate to metastatic spread, are discussed.
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PMID:Lectin-like activities associated with human and murine neoplastic cells. 616 52

Two monoclonal antibodies (KH-1 and KH-2) against a transplanted fibrosarcoma (KMT-17) in WKA rats were produced by fusing a mouse myeloma (P3-X63-Ag8.653) with spleen cells from syngeneic rats hyperimmunized with KMT-17. Both antibodies showed complement-dependent cytotoxicity against KMT-17. By absorption of cytotoxicity, KH-1 reacted with homologous tumor, other syngeneic fibrosarcomas (KMT-80 and KMT-75), and lung and kidney from normal rats. However, KH-2 reacted with many kinds of tumors and various normal tissues. Antigen specificity was tested by complement fixation and/or solid-phase radioimmunoassay using glycolipids isolated from KMT-17 cells and authentic glycolipids. KH-1 reacted with globotriglycosyl ceramide which was not detected on KMT-17 cells and in cross-reacted weakly with IV3-alpha-galactosyl-lactoneotetraglycosyl ceramide, one of the major glycolipids of KMT-17. The immune reaction was inhibited by alpha-methyl-galactose. KH-2 reacted with lactosyl ceramide and lactoneotetraglycosyl ceramide. The reaction was more potently inhibited by lactose than by beta-methyl-galactose. Antibodies with similar specificity to either KH-1 or KH-2 were elevated in syngeneic rat sera after serial immunization with viable KMT-17 cells.
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PMID:Carbohydrates as antigenic determinants of tumor-associated antigens recognized by monoclonal anti-tumor antibodies produced in a syngeneic system. 620 27

Epidemiologic studies have suggested that sugar consumption is correlated with risk of breast cancer. We tested this possibility using the 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumor rat model. Rats were fed diets containing one of three carbohydrates: sucrose, lactose, or corn starch. Tumor yields were similar in the groups fed sucrose and corn starch but significantly lower in the animals fed lactose. Consumption of starch was associated with the most palpable tumors which weighed significantly more than tumors from the other groups. These data indicate significant effects on promotion of mammary tumorigenesis by dietary carbohydrates.
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PMID:Comparison of dietary carbohydrates for promotion of DMBA-induced mammary tumorigenesis in rats. 642 8

The binding of Ricinus communis lectins to HeLa cells, Sarcoma 180 ascites tumor cells and human erythrocytes was studied in detail. Scatchard plots of binding of 125I-lectins to these cells gave biphasic lines except for HeLa cells at 0 degree C. The association constants of lectins for the three cell types at 37 degrees C were lower than those at 0 degree C. The numbers of total binding sites were estimated to be 7 to 16 X 10(7) per HeLa cell, 3 to 4 X 10(7) per Sarcoma 180 ascites tumor cell and 0.4 to 1 X 10(6) per erythrocyte. A fraction, 16 to 27% of the total amount of cell-bound lectin at 37 degrees C, appeared to be bound irreversibly as judged by non-removal on washing with 0.1 M lactose, whereas no lectin was irreversibly bound at 0 degree C. In the case of erythrocytes, no lectin became irreversibly bound even at 37 degrees C. The toxicity of lectins on HeLa cells and Sarcoma 180 ascites tumor cells was investigated. The toxicity of ricin D was 50 times for Sarcoma 180 ascites tumor cells and 140 times for HeLa cells as much as that for castor bean hemagglutinin. As to the sensitivities of both cell types to these lectins, it became apparent that Sarcoma 180 ascites tumor cells were more susceptible than HeLa cells.
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PMID:Binding and cytotoxicity of Ricinus communis lectins to HeLa cells, Sarcoma 180 ascites tumor cells and erythrocytes. 650 Dec 47


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