Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.23.5 (cathepsin D)
 4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A significant elevation of cathepsin D activity was observed in six human hepatoma tissues as compared to 12 normal human livers. In isoelectric focusing experiments, cathepsin D purified from normal liver exhibited three different forms, with isoelectric points of 5.6, 6.1, and 6.7, while cathepsin D purified from hepatoma contained another five to six more acidic forms in addition to the forms observed in normal liver cathepsin D. When the tumor enzyme was treated with endo-beta-N-acetylglucosaminidase H followed by isoelectric focusing, the acidic components disappeared and were converted to forms identical to those of the normal liver cathepsin D. Determination of the mannose-6-phosphate content showed that hepatoma cathepsin D contains twice as much mannose-6-phosphate as normal liver cathepsin D. Peptide mapping and amino acid analysis showed that the protein moiety of cathepsin D from hepatoma is almost identical with that from normal liver. These findings indicate that the appearance of acidic variants in hepatoma cathepsin D is mainly due to changes in the oligosaccharide chains of the enzyme, which are closely associated with the increase of mannose-6-phosphate in the tumor enzyme.
Cancer Res 1988 Jan 15
PMID:Elevated activity and increased mannose-6-phosphate in the carbohydrate moiety of cathepsin D from human hepatoma. 282 73

The pro-cathepsin D of Mr 52,000 is regulated by estrogens via the estrogen receptor (RE) and is secreted by breast cancer cells in vitro. In an attempt to predict the hormone responsiveness of breast cancer in vivo, we have assayed total 52K cathepsin D and its precursor in the primary breast cancer cytosol of 36 patients treated before surgery with 30 mg of tamoxifen daily for 1 to 5 weeks (average, 3 weeks). Compared to a similar control population, total 52K cathepsin D was increased by tamoxifen (P = 0.02) but less so than its precursor (P less than 0.001). Furthermore, 45% of the RE-positive tumors from tamoxifen-treated patients had a higher cathepsin D precursor concentration than the same type of tumor from control patients, or than RE-negative tumors from tamoxifen-treated patients. This 3-week challenge test was probably too short to avoid partial estrogenic activity of tamoxifen (flare) and the authors infer that longer time of treatment would decrease rather than increase the concentration of cathepsin D in the RE-responsive tumors. However, two cancers from patients with relapses after prolonged tamoxifen treatment (greater than 6 months) also had high concentrations of 52K cathepsin D and its precursor. The authors conclude that the concentration of cathepsin D and its precursor in breast cancer cytosol can be increased by short-term tamoxifen treatment, suggesting that these tumors are estrogen responsive.
Cancer 1989 Apr 01
PMID:Tamoxifen treatment increases the concentration of 52K-cathepsin D and its precursor in breast cancer tissue. 292 Mar 55

The Mr 52,000 cathepsin-D-like protease induced by estrogens in MCF7 human breast cells was assayed in 182 primary breast cancer cytosols prepared for receptor assays from pre- and post-menopausal patients. Using two solid-phase sandwich immunoenzymatic assays, we quantified the total Mr 52,000 cathepsin D (52K-cath-D) (the Mr 52,000 precursor protein and its Mr 48,000 and 34,000 processed forms) and the Mr 52,000 precursor alone. The value of total 52K-cath-D varied between 3 and 165 pmol/mg protein and the proportion of the precursor varied from 0 to 28% of total 52K-cath-D. There was no correlation between the concentrations of 52K-cath-D and estrogen receptor, but the estrogen receptor status (greater than or less than 10 fmol/mg protein) was correlated to the 52K-cath-D status (greater than or less than 15 pmol/mg protein) according to the chi 2 test (P less than 0.001). The correlation with progesterone receptor concentrations and status was low (r = 0.43) and absent, respectively. There was no correlation with Scarff and Bloom stages, tumor size, or patient's age. The percentage of patients with invaded lymph nodes was significantly higher (80%) in the subgroup with the highest total 52K-cath-D levels (greater than or equal to 42 pmol/mg protein), representing only 12% of the population but not in the total population. On the basis of this prospective study, before clinical follow-up can be evaluated, we conclude that in the total population examined, the 52K-cath-D concentration was only correlated with estrogen receptor status, but not with any other prognostic parameter.
Cancer Res 1988 Jan 15
PMID:Immunoenzymatic assay of Mr 52,000 cathepsin D in 182 breast cancer cytosols: low correlation with other prognostic parameters. 327 97

The correlation between proteinase activities and invasive and metastatic potentials was investigated by comparing three different kinds of tumors. Extracts from tumor homogenate of 11 squamous cell carcinoma (SCC), 5 basal cell epithelioma (BCE), and 8 seborrheic keratosis (SK) were prepared in order to examine the activity of acid phosphatase and proteinases such as cathepsin B and D, type I and IV collagenase, and plasminogen activator (PA). There was no difference observed between acid phosphatase and cathepsin D activities among the three tumors. Cathepsin B and PA activities were slightly elevated in SCC. Type I collagenase activity of SCC was 9-fold higher than that of SK (p less than 0.01), and type IV collagenase was 3-fold higher per tissue DNA (p less than 0.05). Type I and IV collagenase of BCE were elevated per tissue protein but not elevated per tissue DNA. Correlation was found between the level of cell differentiation in SCC and the activities of cathepsin B, PA, and type I collagenase. Poorly differentiated SCC exhibited a tendency to have higher proteinase activities. Proteinases that showed high activities in malignant tumor homogenate may be related to the degradation of the surrounding cell matrix in addition to intracellular metabolism. Type I and IV collagenase, in cooperation with cathepsin B and PA, might play a major role in invading the dermal stroma and basement membrane.
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PMID:Comparison of proteinase activities in squamous cell carcinoma, basal cell epithelioma, and seborrheic keratosis. 328 80

It has been proposed that proteases secreted by cancer cells facilitate metastasis by degrading extracellular matrix. Estrogen receptor-positive breast cancer cells secrete a Mr 52,000 pro-cath-D under estrogen stimulation, whereas this protease is produced constitutively by estrogen receptor-negative cancer cells. We report on the degradation in vitro of extracellular matrix by purified Mr 52,000 cathepsin D (cath-D) and by conditioned media prepared from different cell lines. The purified Mr 52,000 pro-cath-D was autoactivated at pH 4.5 into a Mr 51,000 cath-D and found to digest the extracellular matrix of endothelial bovine corneal cells labeled with [3H]proline or [35S]methionine. Culture medium conditioned by estrogen-treated MCF7 cells had a similar effect at pH 4.5 but not at pH 7.4. Matrix degradation was totally inhibited by pepstatin. Other breast cancer cells (BT20, MDA-MB231, T47D cells, etc.) and other cancer cells also secreted a pepstatin-sensitive proteinase able to degrade extracellular matrix. By contrast, the U2 variant of MCF7 cells, which lacks the Mr 52,000 cath-D gene, and the nontumoral epithelial mammary cells secreted a negligible amount of this proteinase. In all conditioned media, the pepstatin-dependent extracellular matrix degrading activity was highly correlated to the Mr 52,000 cath-D concentration measured by immunoenzymatic assay. We conclude that the Mr 52,000 cath-D is the major acidic protease secreted by mammary cancer cells. We suggest that this protease may degrade basement membrane and consequently facilitate tumor invasion when it is released in an acidic microenvironment.
Cancer Res 1988 Jul 01
PMID:In vitro degradation of extracellular matrix with Mr 52,000 cathepsin D secreted by breast cancer cells. 337 11

We have studied the posttranslational modifications of the 52-kD protein, an estrogen-regulated autocrine mitogen secreted by several human breast cancer cells in culture (Westley, B., and H. Rochefort, 1980, Cell, 20:353-362). The secreted 52-kD protein was found to be phosphorylated mostly (94%) on high-mannose N-linked oligosaccharide chains, and mannose-6-phosphate signals were identified. The phosphate signal was totally removed by alkaline phosphatase hydrolysis. The secreted 52-kD protein was partly taken up by MCF7 cells via mannose-6-phosphate receptors and processed into 48- and 34-kD protein moieties as with lysosomal hydrolases. By electron microscopy, immunoperoxidase staining revealed most of the reactive proteins in lysosomes. After complete purification by immunoaffinity chromatography, we identified both the secreted 52-kD protein and its processed cellular forms as aspartic and acidic proteinases specifically inhibited by pepstatin. The 52-kD protease is secreted in breast cancer cells under its inactive proenzyme form, which can be autoactivated at acidic pH with a slight decrease of molecular mass. The enzyme of breast cancer cells, when compared with cathepsin D(s) of normal tissue, was found to be similar in molecular weight, enzymatic activities (inhibitors, substrates, specific activities), and immunoreactivity. However, the 52-kD protein and its cellular processed forms of breast cancer cells were totally sensitive to endo-beta-N-acetylglucosaminidase H (Endo H), whereas several cellular cathepsin D(s) of normal tissue were partially Endo H-resistant. This difference, in addition to others concerning tissue distribution, mitogenic activity and hormonal regulation, strongly suggests that the 52-kD cathepsin D-like enzyme of breast cancer cells is different from previously described cathepsin D(s). The 52-kD estrogen-induced lysosomal proteinase may have important functions in facilitating the mammary cancer cells to proliferate, migrate, and metastasize.
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PMID:Phosphorylation, glycosylation, and proteolytic activity of the 52-kD estrogen-induced protein secreted by MCF7 cells. 354 22

Activities of several proteinase-like peptidases have been determined in homogenates of malignant tissue, non-malignant tissue adjacent to the tumour (A-NM) and non-malignant tissue distant to the tumour (D-NM) from 17 patients undergoing surgery for histologically confirmed gastric malignancies. In homogenates of malignant tissues the activities of collagenase, cathepsin B, cathepsin (B+L), cathepsin H and cathepsin D were significantly higher than in D-NM tissues. By contrast, the levels of plasminogen activator were significantly lower in malignant tissues than in the D-NM tissues. Furthermore, the activities of collagenase-like and the cysteine-proteinase-like peptidases in the A-NM tissues were lower than in malignant tissues but higher than in the D-NM tissues. Separation of full-thickness non-malignant tissues into mucosal and seromuscular layers revealed significantly higher activities in the former. The elevated levels of these proteinase-like peptidases in homogenates of gastric cancer tissue suggests an important role for these enzymes in tumour invasion.
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PMID:Proteinase-like peptidase activities in malignant and non-malignant gastric tissue. 388 38

This study was carried out to evaluate the influence of long-term treatment with doxorubicin (DXR) (4 mg/kg IV for 5 weeks) on heart and liver lysosomes of mice. We evaluated the variations in both total and "sedimentable" enzyme activity of cathepsin D, which is the major endopeptidase of myocites and probably involved in physiologic and pathologic degradation of actomyosin and mitochondria, and that of acid phosphatase, which is more prominent in interstitial cells. Our results show that marked changes occur in both total and sedimentable enzyme activity of cathepsin D in the heart of treated animals and to a lesser extent in the liver. In contrast, no modification of either total or sedimentable acid phosphatase was seen in either organ. The effects we observed are much more marked for cardiac cathepsin D; this is in good agreement with the cardiac specificity of DXR-induced cardiotoxicity with long-term administration and suggests that lysosomes could play a role in the pathogenesis of this phenomenon.
Cancer Chemother Pharmacol 1985
PMID:Lysosomal alterations in heart and liver of mice treated with doxorubicin. 400 46

Both malignant (adenocarcinomas) and nonmalignant (fibroadenomas and normal tissue) human breast tissues were maintained in organ culture for up to 10 days to study the secretion of lysosomal and neutral proteinases. Little difference was observed between the different tissue groups in the release of the lysosomal proteinase cathepsin D into the culture medium. Similar results were obtained when media were tested for plasminogen activator activity. The secretion of collagenolytic activity was investigated with fibroadenoma and adenocarcinoma explants and found to be very low for both tissue groups. The average accumulation of collagenase activity during a 2-day period was 0.002 units/microgram DNA for adenocarcinomas and 0.008 units/microgram DNA for fibroadenomas. The only proteinase that was secreted in substantially higher amounts from explants of malignant tissue was a cathepsin B-like thiol proteinase. Media from adenocarcinoma explants (n = 38) contained on the average 11 times more activity than did media from fibroadenoma (n = 20) and normal tissue explants (n = 8). Metastases of mammary adenocarcinomas (n = 7) secreted the thiol proteinase at about one third of the rate of primary tumors. The secretion of this enzyme is dependent upon protein synthesis as its release was completely inhibited 24 hr after the addition of cycloheximide. In some cases, it was also observed that the presence of sheep serum in the tissue culture medium reduced the accumulation of activity.
Cancer Res 1980 Mar
PMID:Secretion of proteinases from malignant and nonmalignant human breast tissue. 625 82

We have demonstrated that incubation of rat liver microsomes with N-hydroxy-2-acetylaminofluorene (N-OH-AAF) leads to formation of a 2-nitrosofluorene-membrane lipid adduct. This adduct exists as a nitroxyl free radical, termed N-O-LAF, in its oxidized state. When microsomes were incubated with the sulfhydryl binding agent, rho-hydroxymercuribenzoate, a larger amount of N-OL-LAF formed. We interpret this as a slowdown in the rate of endogenous chemical reduction of carcinogen-membrane lipid adduct. In this paper we present evidence that N-OH-AAF is deacetylated by a microsomal enzyme to form N-hydroxy-2-aminofluorene and this is then oxidized to 2-nitrosofluorene which adds covalently to membrane lipid double bonds to form N-O-LAF. Various antioxidants, peroxidase inhibitors, and P450 substrates and inhibitors were ineffective in altering the amount of N-O-LAF formed from N-OH-AAF; but two esterase inhibitors, dietyl-rho-nitrophenylphosphate and alpha-toluene-sulfonyl fluoride, prevented N-O-LAF formation. Of the following purified enzymes tested: porcine liver carboxyl esterase, pepsin, chymotrypsin, cathepsin D, ficin, papain, leucine aminopeptidase, Naja naja phospholipase, acetylcholinesterase (type I), trypsin (type I and V) and epoxide hydrase; only carboxyl esterase was effective in deacetylating N-OH-AAF.
Cancer Biochem Biophys 1980
PMID:The deacetylation of N-hydroxy-2-acetylaminofluorene by rat liver microsomes and carboxyl esterase. 626 Mar 32


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