alpha-chymotrypsin and Carcinoma-256--Walker

Topics: Animals; Arginase; Asparaginase; Carcinoma 256, Walker; Carcinoma, Brown-Pearce; Carcinoma, Ehrlich Tumor; Carcinoma, Krebs 2; Chymotrypsin; Deoxyribonucleases; Enzyme Therapy; Glutaminase; Hyaluronoglucosaminidase; Leukemia, Experimental; Leukemia, Radiation-Induced; Lyases; Lymphoma, Non-Hodgkin; Mammary Neoplasms, Experimental; Mice; Neoplasms, Experimental; Pyridoxal Phosphate; Rats; Ribonucleases; Salts; Sarcoma, Avian; Sarcoma, Experimental; Trypsin; Vanadium

Topics: Amylases; Animals; Arginase; Benz(a)Anthracenes; Carcinoma; Carcinoma 256, Walker; Carcinoma, Brown-Pearce; Carcinoma, Ehrlich Tumor; Catalase; Chymotrypsin; Deoxyribonucleases; Enzyme Therapy; Humans; Hyaluronoglucosaminidase; Mammary Neoplasms, Experimental; Mice; Neoplasms, Experimental; Osteosarcoma; Peroxidases; Rats; Ribonucleases; Sarcoma; Sarcoma 180; Sarcoma, Experimental; Trypsin

Cancer-cachexia causes severe weight loss, particularly from the wasting of skeletal muscle, which occurs due to increased protein catabolism and/or decreased protein synthesis. The muscle protein degradation observed in cancer patients is mediated by a specific cytokine, proteolysis-inducing factor (PIF), which is produced by the tumour. This protein increases the ubiquitin-proteasome pathway activity, and the synthesis of muscle protein in these patients can be affected by several factors, including nutrient-related signalling. Some nutrients, such as leucine, can decrease the ubiquitin-proteasome pathway activity and increase the skeletal muscle protein content in cachectic animals. In this study, we investigated the effects of leucine on cell viability, morphology, functional proteasome activity, enzymatic activity, and protein synthesis and degradation in C2C12 myotubes exposed to the proteolysis-inducing factor (PIF)-like protein purified from Walker tumour-bearing rats. Walker factor (WF) had no cytotoxic effects on myotube cells and morphological characteristics were not altered in the presence of WF and/or leucine. However, increased alkaline phosphatase activity was observed. At higher WF concentrations, chymotrypsin-like activity, cathepsin B activity and 20S proteasome gene expression increased. Treating myotubes with leucine before exposure to WF causes leads to a decrease in proteasome activity as well as the activity of chymotrypsin and cathepsin enzymes. Total protein synthesis decreased in WF-treated cells concomitantly as protein degradation increased. After leucine exposure, the observed effects of WF were minimal or even reverted in some cases. Taken together, these results suggest an important modulatory effect for leucine on the effects of WF in C2C12 myotube cells.

Topics: Alkaline Phosphatase; Animals; Cachexia; Carcinoma 256, Walker; Cathepsin B; Cell Survival; Chymotrypsin; Gene Expression; Leucine; Male; Muscle Fibers, Skeletal; Proteasome Endopeptidase Complex; Protein Biosynthesis; Proteoglycans; Proteolysis; Rats; Rats, Wistar

Dynamics of the expression of MHC class I, immune proteasomes and proteasome regulators 19S, PA28, total proteasome pool and proteasome chymotrypsin-like activity in Walker 256 tumor after implantation into Brattleboro rats with the hereditary defect of arginine-vasopressin synthesis was studied. The tumor growth and regression in Brattleboro rats were accompanied by changes in the proteasome subunit level unlike the tumor growth in WAG rats with normal expression of arginine-vasopressin gene. In the tumor implanted into Brattleboro rats the immune proteasome level was maximal between days 14 and 17, when the tumor underwent regression. Conversely, the expression of proteasome regulators tended to decrease during this period. Immune proteasomes are known to produce antigen epitopes for MHC class I to be presented to CD8+ T lymphocytes. Enhanced expression of immune proteasomes coincided with the recovery of MHC class I expression, suggesting the efficient presentation of tumor antigens in Brattleboro rats.

Topics: Animals; Antigen Presentation; Antigens, Neoplasm; Arginine Vasopressin; Carcinoma 256, Walker; Chymotrypsin; Cysteine Endopeptidases; Histocompatibility Antigens Class I; Male; Neoplasm Regression, Spontaneous; Neoplasm Transplantation; Proteasome Endopeptidase Complex; Rats; Rats, Brattleboro

8-Carbamoyl-3-(2-chloroethyl)imidazo[5,1-d]-1,2,3,5-tetrazin-4-(3H )-one- mitozolomide (CCRG 81010, M & B 39565, NSC 353451) is a potent inhibitor of the growth of a number of experimental tumours and can potentially decompose to give either an isocyanate or the monochloroethyltriazene (MCTIC). In vitro CCRG 81010 is not cross-resistant with the bifunctional alkylating agents against the Walker carcinoma. To investigate the mechanism of the antitumour activity of CCRG 81010 a comparison has been made with BCNU and MCTIC on precursor incorporation into macromolecules in TLX5 mouse lymphoma cells. Whereas BCNU produces a rapid and extensive inhibition of both (methyl 3H) thymidine and [5-3H]uridine incorporation into acid-insoluble material, neither CCRG 81010 or MCTIC have an early effect on precursor incorporation. Inhibition of precursor uptake is also not produced by concentrations of 2-chloroethylisocyanate that inhibit intracellular glutathione reductase activity. The potential carbamoylating activity of CCRG 81010 has also been assessed by comparing its effect with that of BCNU and 2-chloroethyl isocyanate on enzymes known to be inhibited by carbamoylation. Such enzymes, glutathione reductase, chymotrypsin and gamma-glutamyltranspepidase are not inhibited by CCRG 81010 under conditions where BCNU and 2-chloroethyl isocyanate show complete inhibition of enzyme activity, suggesting an absence of carbamoylating species. The results suggest that the most likely antitumour metabonate produced from CCRG 81010 is the triazene MCTIC.

Topics: Adenosine; Aminoimidazole Carboxamide; Animals; Antineoplastic Agents; Carcinoma 256, Walker; Carmustine; Cells, Cultured; Chymotrypsin; DNA, Neoplasm; gamma-Glutamyltransferase; Glutathione Reductase; Imidazoles; Lymphoma; Mice; Nitrogen Mustard Compounds; Thymidine; Uridine

A latent form of collagenase had been isolated from crude extracts of the insoluble, fibrous material from Walker tumor homogenates. Purified preparations of this enzyme yielded a major unit of Mr approximately 62000, as determined by gel filtration on AcA 54 Ultrogel. In its activated form collagenase had been purified to apparent homogeneity with an approximate Mr of 42000. The active enzyme cleaved soluble collagen into three-quarter and one-quarter length fragments in the manner of vertebrate collagenases. Latent collagenase from culture media eluted with an apparent Mr of 53000 and was thus slightly larger in size than its activated form that eluted at 42000. Extracted latent collagenase and latent collagenase from culture media could be activated enzymatically by trypsin or chymotrypsin and non-enzymatically by mersalyl, an organic mercurial compound. We suggest that latent collagenase from Walker tumors are complexes of active enzyme with inhibitor(s) of low molecular weight(s) and are not true zymogens.

Topics: Animals; Carcinoma 256, Walker; Chromatography, Gel; Chymotrypsin; Collagen; Enzyme Activation; Male; Mersalyl; Microbial Collagenase; Molecular Weight; Rats; Rats, Inbred Strains; Trypsin

The inhibitory activity of 1058 inhibitors of the title enzymes has been formulated in 13 equations correlating chemical structure with inhibitory potency. Two types of regions in enzymes have been defined by means of pi and molar refractivity constants. The use of indicator variables has been extensively developed to suggest special enzyme-ligand interactions. Several examples are given of the use of correlation equations in comparing structural features of different systems.

Topics: Animals; Benzamidines; Carcinoma 256, Walker; Chymotrypsin; Columbidae; Cytidine Deaminase; Escherichia coli; Folic Acid Antagonists; Glutamate Dehydrogenase; Glyceraldehyde-3-Phosphate Dehydrogenases; In Vitro Techniques; Kinetics; L-Lactate Dehydrogenase; Liver; Malate Dehydrogenase; Methyltransferases; Nucleoside Deaminases; Pentosyltransferases; Rats; Structure-Activity Relationship; Thymidylate Synthase; Trypsin Inhibitors; Uridine Phosphorylase