Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A specific collagenase (EC 3.4.24.3) has been found and purified from serum-free culture medium of 11095 epidermoid carcinoma of rat prostate. The molecular weight of this collagenase was estimated at 71 000 and the pH optimum was approx. 7. At 26 degrees C, the collagenase cleaved collagen at a site 3/4 the length from the N-terminus. At 37 degrees C, this collagenase degraded collagen to smaller peptides. The enzyme activity was inhibited by serum, cysteine and EDTA, but not by protease inhibitors. The presence of collagenase in rat tumor tissue suggests that this enzyme might play a significant role in tissue invasion by cancer cells.
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PMID:Collagenase activity in cultures of rat prostate carcinoma. 3 9

Tight junctions adjacent to the tumor stromal interface in invading neoplastic cells of human urinary bladder carcinomas were observed. Basal lamina, collagen and elastic fibers, and cellular debris were found next to the tight junctions. An association between microenvironment (i.e., tumor necrosis) of the invading neoplastic cells and tight junction locations was suggested.
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PMID:Tight junctions adjacent to tumor stromal interface in human invasive transitional cell carcinomas. 4 9

Proteases capable of activating procollagenase from gingiva and from fibroblast and macrophage monolayer cultures were harvested from homogenates of canine tumor mast cells. The mast cell proteases lysed casein and Azocoll but not native collagen. In low salt concentrations the enzymes existed at high molecular weight complexes, which were dissociated by increasing the salt concentration above 1.0 M (NaCl, KCl). Gel filtration in 1.4 M KCl separated the protease activity into three peaks, all of which activated procollagenase. Two of the enzymes showed substrate specificities (hydrolysis of p-tosyl-L-arginine methyl ester and benzoyl-tyrosine ethyl ester) and reactive center reactivities similar to pancreatic trypsin and chymotrypsin. Based on gel filtration, apparent molecular weights of 160 000 (p-tosyl-L-arginine methyl ester esterase), 90 000 (main procollagenase activator) and 36 000 benzoyl-tyrosine ethyl ester esterase) were determined. Activation of procollagenase resulted in a 18-20 000 decrease of the molecular weight. The activation was directly related to the amount of activator added within certain limits. Further addition of activator resulted in proteolytic inactivation of collagenase.
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PMID:Activation of fibroblast procollagenase by mast cell proteases. 5 9

Five cases of adenoid cystic carcinoma of minor salivary glands were studied. The mucoid material in the characteristic cystlike space of this neoplasm was distaseresistant periodic acid-Schiff (PAS)--positive, alcain blue-positive, toluidine blue-positive, and mucicarmine-positive. Verhoeff-Van Gieson's method and Weighert's method did not reveal elastic tissue in the cystlike spaces. Mallory's method revealed that a central core in cystlike spaces was similar in stainability to collagen. Wilder's method did not reveal reticular fibers in these spaces. Electron microscopy revealed three readily recognizable zones: a juxtacellular zone of a network of replicated basal lamina, and intermediate zone of stellate granules of mucoid material, and a central core of densely packed aperiodic filaments or collagen fibrils. The histogenesis of cystlike spaces and their realtionship with biologic behaviors of the neoplasm were discussed.
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PMID:Adenoid cystic carcinoma of minor salivary gland. Histochemical and electron microscopic studies of cystlike space. 6 33

The effects of three different dosage schedules on both therapeutic effect and pulmonary toxicity of bleomycin were studied in mice. Therapy was assessed by both survival and decreased tumor size in mice bearing Lewis lung carcinoma. Lung toxicity was estimated in nontumored mice as increases in lung collagen content by measuring lung hydroxyproline concentrations. In the first set of experiments, bleomycin injections twice daily (low-dose, high-frequency) produced a significant (34%) increase in lifespan over controls, whereas the same total dose given twice weekly did not result in increased survival. Both schedules produced pulmonary toxicity. Continuous sc infusion of bleomycin via an osmotic minipump was compared to these two schedules of intermittent injection. Identical total doses of drug were administered in all three schedules. Continuous infusion for 7 days produced marked inhibition of tumor growth (T/C = 16%), which was significantly better than twice weekly or ten-times weekly injection of the same total dose. Furthermore, at a total dose of 40 mg/kg of bleomycin, continuous infusion did not result in measurable pulmonary toxicity, whereas both schedules of bolus injection produced significant increases in lung collagen content. Thus, continuous infusion of bleomycin improved its therapeutic effect against Lewis lung carcinoma and also reduced its pulmonary toxicity.
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PMID:Improved therapeutic index of bleomycin when administered by continuous infusion in mice. 8 69

Tw osteosarcomas of jaw bones have been studied by electron microscopy. The objectives were to examine the specific cell types in relation to functions and ultrastructural features, and to examine matrices produced by tumor cells. The osteosarcoma cells were subdivided into four cell types: anaplastic, chondroblastic, osteoblastic, and osteocytic--giant cells were not considered in the present investigation. Compared to normal bone cells, no specific sign of malignancy was found. However, tumor cells seem to lose functional abilities, i.e. a modification of matrix. Consequently, tumor matrix has altered organic and inorganic components with impairment of collagen maturation and matrix mineralization. The alteration in both processes may be related to a diminished production of proteoglycans. The cytogenic hypothesis of a tumor stem cell may be supported by the identification of anaplastic osteosarcoma cells resembling immature reticulum cells. One may speculate on transformation of this cell type as a genetically predetermined osteoprogenitor cell of malignant potential.
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PMID:Ultrastructural study of tumor cell differentiation in osteosarcoma of jaw bones. 9 36

The cutaneous nodules obtained from seven patients with von Recklinghausen's neurofibromatosis were investigated by electron microscopy, and ultrastructural localization of acetylcholinesterase activity was demonstrated in the nerve fibers of this tumor for the first time using Karnovsky's thiocholine method. The enzymatic activity was mainly found in unmyelinated fibers, exactly associated with their axonal membranes, the interspace between the apposing axonal and Schwann cell membrane, and some different mesaxons, which indicated their cholinergic nature. Almost all myelinated fibers and some unmyelinated fibers did not possess the activity. The relationship between axon and Schwann cell was quite similar to that of normal peripheral nervous system, but two striking alterations of the nerves existed: One is the dissociation of unmyelinated fibers, and the other is the degenerative changes of the axon and the myelin sheath. As the evidence of schwannian proliferation, onion bulb formations and collagen pockets were observed. Some signs of fibroblastic proliferation were also found. From the present study and the review of the literature, the probable histogenesis of this disease was discussed.
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PMID:Study on the ultrastructure and acetylcholinesterase activity in von Recklinghausen's neurofibromatosis. 9 62

The ultrastructural features of a juvenile ossifying fibroma of the maxilla are described. The stromal portion of the tumor was composed of osteoblasts and to a lesser extent of fibroblasts. The bone spicules were rimmed by osteoblasts and osteoclasts. Calcification was seen to occur along the collagen fiber matrix, corresponding to calcification of osteoid, and also in the form of intracellular and extracellular crystallization. The latter form of calcification corresponded to so-called psammoma-like bodies, and was considered characteristic of this subtype of ossifying fibroma.
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PMID:Juvenile ossifying fibroma: an ultrastructural study. 10 13

Collagen synthesis is increased over three-fold in capsules surrounding dimethylbenzanthracene-induced rat breast tumors compared to the tumor parenchyma and over six-fold compared to normal breast connective tissue. Increased collagen synthesis is independent of the rate of tumor growth and final tumor size. Pretreatment of animals with beta-aminopropionitrile to inhibit collagen cross-linking caused an 82% decrease in tumor formation and a significant reduction in tumor volume (approximately 0.4 cu cm) compared to controls (approximately 10 cu cm). The four small tumors that did develop in the lathyritic animals had increased collagen synthesis in the interior tumor stroma and reduced collagen synthesis in the tumor capsule. These findings suggest that the collagenous capsule surrounding dimethylbenzanthracene tumors functions as a physical barrier to protect the tumor from the immune system of the host. The apparent antitumor effects of beta-aminopropionitrile may be due to immunopotentiation and/or cytotoxic actions of the drug.
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PMID:Collagen synthesis in capsules surrounding dimethylbenzanthracene-induced rat breast tumors and the effect of pretreatment with beta-aminopropionitrile. 11 Apr 42

We have isolated a large noncollagenous glycoprotein, laminin, from a mouse tumor that produces basement membrane. The protein consists of at least two polypeptide chains (Mr = 220,000 and Mr = 440,000) joined to each other by disulfide bonds. Laminin and type IV collagen are major constituents of the tumor. Laminin is distinctly different from fibronectin, another component of basement membranes, in amino acid composition and immunological reactivity. Pepsin digestion of laminin releases a large, cystine-rich fragment which retains most of the antigenicity of the original protein. Immunological studies using purified antibody against laminin show that it is produced by a variety of cultured cells. In addition, these antibodies react with the basement membranes of normal tissues, suggesting that this protein or an immunologically related protein is a constituent of the basement membranes of these tissues.
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PMID:Laminin--a glycoprotein from basement membranes. 11 18


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