Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.23.5 (cathepsin D)
4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activity of arylsulphatase, beta-glucuronidase, cathepsin D, and acid phosphatase in the homogenates of melanotic and amelanotic melanoma was determined. The activity of these enzymes is higher in melanotic than in amelanotic melanoma. Respective values for melanotic and amelanotic tumours are: arylsulphatase 10,78 +/- 3,20, and 1,45 +/- 0,66 micron 4-nitrocatechole/mg protein/hr; beta-glucuronidase 11,10 +/- 1,40, and 9,98 +/- 1,35 micron phenolphthalein/mg protein/hr; cathepsin D 4,24 +/- 1,37, and 3,26 +/- 0,73 micron tyrosine/mg protein/hr; acid phosphatase 230 +/- 22, and 180 +/- 25 micron p-nitrophenol/mg protein/hr. These differences are statistically significant. The increased activity of the lysosomal enzymes in melantoic melanoma probably depends on the occurrence of an higher number of lysosomes in tissues containing melanins.
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PMID:Activity of some lysosomal hydrolases in the homogenates of transplantable melanotic and amelanotic melanoma in golden hamster (Mesocricetus auratus, Waterhouse). 68 81

A high percentage of the total tyrosinase found in Harding-Passey mouse melanoma occurs as a soluble form. This paper shows that melanosomal tyrosinase can be solubilized by several endogenous proteases to yield active tyrosinase. This enzyme, once proteolytically solubilized, can be further degraded, leading to enzyme inactivation. The nature and specificity of the main proteases involved in the solubilization process change depending on the size and necrosis stage of the tumour. Cathepsin B could be the main protease responsible for the solubilization in small tumours (less than 0.5 g). Large tumours are rich in necrotic cells, and cathepsin D and serine-proteases are the main hydrolytic enzymes involved in the proteolytic action on melanosomes. These results support the view that the high activity of tyrosinase found in the soluble fraction of malignant melanoma is mainly an artefact resulting from degradation of melanosomes by a variety of endogenous proteases, rather than the result of the actual occurrence of high levels of an independent cytosolic isozyme.
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PMID:Action of endogenous proteases on the distribution of tyrosinase isozymes in Harding-Passey mouse melanoma. 250 24

In solid s.c. tumors of a variant of the murine B16 melanoma with high metastatic potential (B16F10), there was a 2- to 7-fold elevation of lysosomal cathepsin B activity when compared to the B16F1 variant with low metastatic potential. The highest activities (based on either protein or DNA) of cathepsin B were found in tumors of less than 1 g. When B16F1 and B16F10 melanoma variants were grown in tissue culture, the metastatic differential in cathepsin B activity was lost as the cells were subcultured. However, this differential in cathepsin B activity could be restored by reestablishing the cultured cells as s.c. tumors. The activities of four other lysosomal enzymes (cathepsin D, beta-N-acetylglucosaminidase, beta-glucuronidase, and acid phosphatase) showed little evidence of a positive correlation with the metastatic potential of the B16 melanoma variants. Eighty to 90% of cathepsin B activity has been localized to a fraction containing viable tumor cells which was isolated by centrifugal elutriation. In contrast, only 50% of cathepsin D activity was in the viable tumor cell fraction, and from 30 to 70% of beta-N-acetylglucosaminidase, beta-glucuronidase, and acid phosphatase. Elevated levels of cathepsin B in the high metastatic B16F10 variant are consistent with the idea that cathepsin B may play a direct or a regulatory role in tumor metastasis.
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PMID:Cathepsin B activity in B16 melanoma cells: a possible marker for metastatic potential. 705 93

Trypan blue is known to act as a lysosome membrane destabilizer. We investigated the effect of this dye on the activity of cathepsin D, acid phosphatase and arylsulfatase in tissue homogenates of B16 melanotic melanoma, transplanted subcutaneously in C57BL/6J black male mice. We also examined the tumor growth and the ultrastructure of its cells. The mice were given subcutaneous injections of the suspension of B16 cells (10(6)), and then received the trypan blue solution intraperitoneally in four divided doses, reaching the total does of 0.1 mg/g b.w. (group I) or 0.4 mg/g b.w. (group II). The dye was administered each other day after the tumor transplantation. The control mice were injected with melanoma cells only. The animals were killed 2 weeks after the beginning of the experiment. We found that the activity of lysosome hydrolases was increased by 30% to 50% in groups I and II, respectively, as compared to the control animals. The tumor growth in groups I and II was accelerated, and some ultrastructural changes in the melanoma cells were observed. These included irregular shape of the nucleus, uneven dispersion of the chromatin, increased number of premelanosomes and Golgi structures. The number of lysosomes, however, remained unaltered. We postulate that the trypan blue promotes tumor growth through the enhancement of the activity of lysosomal hydrolases; this may be due to the increased permeability of lysosome membranes caused by the trypan blue.
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PMID:Effect of trypan blue on the activity of lysosomal enzymes, tumor growth and cell ultrastructure in B16 melanotic melanoma in mice. 765 82

High levels of cytosolic cathepsin D expression have been associated with poor prognosis in breast cancer node-negative patients. In this work, we provide evidence that three cell lines established from human metastatic melanomas--IIB-MEL-J, IIB-MEL-LES, and IIB-MEL-IAN--express high levels of procathepsin D mRNA. IIB-MEL-J cells secreted into the conditioned media about 30% of the newly synthesized protein, which was active at acidic pH. Melanoma tumors arising in nude mice after injection of the three different cell lines expressed high levels of procathepsin D mRNA. Moreover, 13 human metastatic melanomas expressed variable levels of procathepsin D mRNA. To study the possible association between cathepsin D expression and melanoma development, samples corresponding to 10 primary tumors, 11 metastatic melanomas, 10 dysplastic nevi, 27 nevocellular nevi, and normal melanocytes were studied by immunohistochemistry for cathepsin D-specific staining. We found that cathepsin D was expressed in all of the dysplastic nevi and primary and metastatic melanomas tested but in only 18% of nevocellular nevi (five of 27), whereas normal melanocytes showed no cathepsin D expression. The overall data indicate that cathepsin D is expressed at a high level by melanoma cells, and because of its expression in preneoplastic lesions, it may be associated with melanoma development.
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PMID:Expression of cathepsin D in primary and metastatic human melanoma and dysplastic nevi. 786 Sep 98

In this study 9 uveal melanomas, 1 iris melanoma and 1 conjunctival melanoma were evaluated for their proliferation activity with antibodies to KI67 protein. In addition, the distribution of glutathion-S transferase (alkaline and acid isoforms) and lysosomal cathepsin D protease was demonstrated immunohistochemically. The expression of the oncoproteins c-neu (internal and external domaine) and ras (mutated and non-mutated isoform) were also analyzed with specific monoclonal antibodies. In the case of the metastasing melanoma significant Ki67 protein expression and marked expression of the oncoproteins ras p21 and pan ras were obvious. All other melanomas showed less proliferation and enzymatic activity with a moderate expression pattern for oncoproteins. Regarding the results of the proliferation and enzymatic markers, the tumors were heterogeneous; single cells or clusters may play a role in the prognosis of the tumor if there is an intense immunohistochemical reaction. The influence of histomorphological criteria, e.g., cell subtype, seems to be minor compared to immunohistochemical criteria.
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PMID:[Proliferation markers, enzyme markers and oncogene expression profile of intraocular melanoma]. 821 45

Melanomas exhibiting mutated ras genes are frequently invasive and amelanotic. Transfecting melanocytes with ras oncogenes causes transformation and a loss of visible pigmentation. We analyzed murine melanocytes rendered amelanotic by transfection with the v-rasHa oncogene. Consistent with previous reports, tyrosinase and tyrosinase-related protein-1 (TRP-1) were not expressed by transformed cells. In addition, lack of expression of TRP-2 and the product of the silver locus was documented. Levels of melanosomal matrix antigens, the pink-eyed dilution locus protein and lysosome-associated membrane protein-1 were markedly reduced. Residual matrix antigens were localized by immunofluorescence to large vacuoles distributed peri-nuclearly in transfected cells. Electron microscopy demonstrated the absence of typical melanosomes and the presence of large vacuolar structures, also in a peri-nuclear distribution. Although levels of lysosomal hydrolases, such as beta-glucuronidase and cathepsin D, were diminished, marked elevations were observed in the expression of cathepsins B and L, 2 thiol proteases implicated in the acquisition of invasiveness. Our data demonstrate that transfection of melanocytes with v-rasHa is sufficient to disrupt the biogenesis of melanosomes and to up-regulate thiol protease synthesis, providing insights into the amelanotic and invasive nature of melanomas exhibiting mutations in ras genes.
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PMID:Melanosomal and lysosomal alterations in murine melanocytes following transfection with the v-rasHa oncogene. 863 74

MHC class II molecules associate with peptides in the endocytic pathway. Different endosomal locations for peptide loading of class II molecules, varying from early endosomes (EE) to lysosomes, have been assigned on the basis of subcellular fractionation experiments. We have determined the intracellular location of HLA-DM, a molecule that supports peptide loading of class II molecules, by separating vesicles from the melanoma cell line Mel JuSo on the basis of buoying density and surface charge. In both fractionations, HLA-DM co-fractionated with a lysosomal compartment containing beta-hexosaminidase (beta-hex) activity and not with endosomes. Further analysis showed that HLA-DM mainly co-fractionated with a sub-lysosomal structure characterized by a relative low density and containing both pro- and mature cathepsin D and MHC class II molecules. Fluid phase markers first enter this compartment before entering high-density lysosomes that contain exclusively mature cathepsin D, some HLA-DM and no detectable MC class II molecules. Finally we determined the intracellular location of neutral and acidic peptidases. Whereas neutral peptidase activity was detected in the endoplasmic reticulum and/or plasma membrane fractions, acidic peptidase activity exclusively migrated at the position of HLA-DM containing lysosomal vesicles. Our results show that class II molecules co-migrate with HLA-DM, pro- and mature cathepsin D, beta-hex and acidic peptidase activity. HLA-DM, cathepsin d and class II molecules were not observed at the position of EE. Our data suggest that HLA-DM-mediated peptide loading of class II molecules occurs in a lysosomal subcompartment.
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PMID:HLA-DM and MHC class II molecules co-distribute with peptidase-containing lysosomal subcompartments. 867 50

The high mortality rate of melanoma patients who develop metastases prompted us to seek for a prognostic soluble marker to identify high-risk and non-risk patients at the stage of the primary tumour. Therefore, we developed a new ELISA for quantifying plasma concentrations of the proteolytic enzyme cathepsin D (CD) in patients with primary tumours (MM-P) and with metastases (MM-M), respectively, compared to a control group. Whereas healthy probands (n = 56) and MM-P (n = 68) showed similar mean values of CD (0.73 +/- 0.45 ng/ml and 0.82 + 0.80 ng/ml), MM-M (n = 40) yielded significantly reduced plasma levels (0.43 +/- 0.53 ng/ml) revealing a high significant discrimination both between controls and MM-M, and MM-P and MM-M (p < 0.0001). From the beginning of the study (1990) to the present 11 of 68 MM-P developed metastases. In order to test the prognostic efficiency of this enzyme to determine those patients at high-risk and non-risk for developing metastases, the receiver operating characteristic analysis was used showing that CD plasma levels cannot supply reliable prognostic values (W = 0.53, p = 0.66).
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PMID:Quantification of cathepsin D in plasma of patients with malignant melanoma. 985 96

Melanosomes and premelanosomes are lysosome-related organelles with a unique structure and cohort of resident proteins. We have positioned these organelles relative to endosomes and lysosomes in pigmented melanoma cells and melanocytes. Melanosome resident proteins Pmel17 and TRP1 localized to separate vesicular structures that were distinct from those enriched in lysosomal proteins. In immunogold-labeled ultrathin cryosections, Pmel17 was most enriched along the intralumenal striations of premelanosomes. Increased pigmentation was accompanied by a decrease in Pmel17 and by an increase in TRP1 in the limiting membrane. Both proteins were largely excluded from lysosomal compartments enriched in LAMP1 and cathepsin D. By kinetic analysis of fluid phase uptake and immunogold labeling, premelanosomal proteins segregated from endocytic markers within an unusual endosomal compartment. This compartment contained Pmel17, was accessed by BSA-gold after 15 min, was acidic, and displayed a cytoplasmic planar coat that contained clathrin. Our results indicate that premelanosomes and melanosomes represent a distinct lineage of organelles, separable from conventional endosomes and lysosomes within pigmented cells. Furthermore, they implicate an unusual clathrin-coated endosomal compartment as a site from which proteins destined for premelanosomes and lysosomes are sorted.
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PMID:Distinct protein sorting and localization to premelanosomes, melanosomes, and lysosomes in pigmented melanocytic cells. 1126 77


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