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M Morisset

Publications and source records attributed to M Morisset.

53 records · Page 3Linked to original sources
PubMed1999

Cross-allergenicity of peanut and lupine: the risk of lupine allergy in patients allergic to peanuts.

BACKGROUND: Peanut allergy is common, but cross-allergy between legumes is rare. Proteins from Lupinus albus are increasingly eaten in the form of seeds or additives to wheat flour. The risk of cross-allergenicity is still insufficiently known. OBJECTIVE: We sought to study the risk of cross-allergy to lupine in patients allergic to peanut and to study lupine allergenicity. METHODS: Twenty-four patients allergic to peanuts were studied by means of skin prick tests with native lupine flour from Lupinus albus. Double-blind oral challenge tests were performed with lupine flour and peanut in 8 of these patients. Specific IgEs were assayed for peanut, lupine flour, and pollen in 6 sera. RAST inhibition tests for lupine pollen by peanut were performed on 4 of these sera. Peanut and lupine flour immunoblots were carried out for 6 sera, and crossed immunoblot inhibitions for peanut by lupine flour and lupine flour by peanut were carried out for 2 sera. RESULTS: The skin prick test responses with lupine flour were positive in 11 (44%) subjects. The challenge test responses were positive in 7 of 8 subjects at the same doses as with peanut. The major lupine flour allergen (molecular mass, 43 kd) is present in peanuts. The RAST inhibition and immunoblot tests indicated cross-reactivity of peanut with the lupine flour and pollen. CONCLUSIONS: The risk of crossed peanut-lupine allergy is high, contrary to the risk with other legumes. The inclusion of 10% lupine flour in wheat flour without mandatory labeling makes lupine a hidden allergen, presenting a major risk of cross-reaction in subjects already allergic to peanut products. A high sensitizing potential can also be postulated for this legume.

Adolescent↗
PubMed1999

[Measurement of levels of specific IgE by the Efficient New Enzymatic Allergy (ENEA) System II (CIS bio)].

The diagnosis of IgE dependant food allergy relies on the demonstration of specific IgE by prick tests or in vitro tests. The ENEA System II (CIS bio international) is a new automatic assay analyser of specific IgE, that uses allergens coupled to a solid phase and a urease marked anti-IgE antibody. This study aims to compare the performance of the ENEA System II to that of Pharmacia CAP System for the assay of food specific IgE (milk, eggs, peanuts) by means of unit tests and multitests. Sixty three patients were included: 10 non atopic controls, 19 egg-allergic patients, 10 patients allergic to cow's milk, and 24 patients allergic to peanuts. The food allergy was proved by means of a double blind oral, labial or bronchial challenge and/or effective avoidance of the food. For both systems, the specificity of unit tests was 100%. Sensitivity was 60% and 100% with both systems, using milk and peanuts respectively. However, using eggs, it was only 74% with ENEA System II versus 95% with Pharmacia CAP System. The intra-trial variation coefficients were comparable. In contrast, inter-trial variation coefficient was very high for the ENEA System II (20.3% versus 7.3%). The multitest named "children's food" showed an important inter-set variability. In conclusion, the ENEA System II is a rapid automatic tester whose performance has to be improved. The actual thermostatically control of the system was shown to achieve quality assay. The conservation of the solid phase, recently perfected, is expected to suppress the inter-set variability.

Adult↗
PubMed1990

Cathepsin D in breast cancer cells can digest extracellular matrix in large acidic vesicles.

In breast cancer cell lines, pro-cathepsin D is synthesized in excess and abnormally processed, resulting in its slower maturation and increased secretion into the culture medium. Since this lysosomal protease is only active at acidic pH, we have searched for acidic compartments other than lysosomes where cathepsin D might be active when MCF7 cells are plated on corneal extracellular matrix. We found large acidic intracellular vesicles (1.5 to 20 microns in diameter) by acridine orange and 3-(2,4-dinitroanilino)-3'-amino-N-methyldipropylamine staining, two fluorescent probes which reveal acidic compartments. These vesicles were actively acidified. They were 2- to 20-fold more abundant in MCF7 breast cancer cells and primary cultures of human breast cancers cells than in primary cultures of normal mammary epithelial cells. In living MCF7 cells, high resolution video-enhanced microscopy showed that these vesicles were mobile and intracellular. Double immunolocalization indicated that they contained mature cathepsin D (but no detectable pro-cathepsin D) and endocytosed extracellular material. This material (dextran, transferrin, and extracellular matrix) and the association with other lysosomal enzymes varied according to the vesicles, suggesting their heterogeneity (large endosomes or phagosomes). We conclude that, in breast cancer cells, cathepsin D may digest intracellularly phagocytosed and/or endocytosed extracellular matrix in large acidic vesicles. We propose that the higher expression of cathepsin D associated with the increased number of large acidic vesicles in breast cancer cells may facilitate digestion of basement membrane and consequently metastasis.

Breast Neoplasms↗
PubMed1988

In vitro degradation of extracellular matrix with Mr 52,000 cathepsin D secreted by breast cancer cells.

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.

Breast Neoplasms↗
PubMed1988

Structure, function, regulation and clinical significance of the 52K pro-cathepsin D secreted by breast cancer cells.

In estrogen-receptor-positive human breast cancer cell lines (MCF7, ZR75-1), estrogens specifically increase the secretion into the culture medium of a 52,000 Da (52K) glycoprotein and stimulate cell proliferation. The 52K protein has been purified to homogeneity using monoclonal antibodies and identified as the secreted precursor of a cathepsin D bearing mannose-6-phosphate signals. The secreted precursor 52K protein is mitogenic in vitro in estrogen-deprived MCF7 cells, can be taken up by these cells via mannose-6-phosphate receptors, and can degrade extracellular matrix and proteoglycans following its auto-activation. The protease is also produced constitutively by ER-negative cell lines, and is inducible by tamoxifen in some antiestrogen-resistant variants. The corresponding cDNA has been cloned using N-terminal sequencing of the protein and monoclonal antibodies. Its complete sequencing indicates a strong homology with pro-cathepsin D of normal tissues. Using a cDNA probe, the regulation of 52K cathepsin D mRNA by estrogens and antiestrogens has been studied and chromosome localization determined by in situ hybridization. Clinical studies using both immunohistochemistry and immunoenzymatic assay of breast cancer cytosol have shown that the concentration of total cellular cathepsin D (52K + 48K + 34K) is related to the proliferation of mammary ducts and to the prognosis of breast cancer. Its cytosolic concentration in primary tumors of postmenopausal patients is correlated slightly with lymph node invasion and significantly with shorter disease-free intervals in a 6-year retrospective study with the Danish Breast Cancer Groups and Finsen Institute (S. Thorpe et al.).(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers, Tumor↗
PubMed1987

Estrogen-induced lysosomal proteases secreted by breast cancer cells: a role in carcinogenesis?

In an attempt to understand the mechanism by which estrogens stimulate cell proliferation and mammary carcinogenesis, metastatic human breast cancer cell lines (MCF7, ZR75-1) were found to secrete a 52,000 dalton (52K) protein under estrogen stimulation. Following its purification to homogeneity, the 52K protein was identified as a secreted procathepsin-D-like aspartyl protease bearing mannose-6-phosphate signals. This precursor displays an in vitro autocrine mitogenic activity on estrogen-deprived MCF7 cells and is able to degrade basement membrane and proteoglycans following its autoactivation. The total protease (52K + 48K and 34K) was detected and assayed by monoclonal antibodies and was found to be highly concentrated in proliferative and cystic mastopathies. In breast cancer, its cytosolic concentration appears to be correlated more to tumor invasiveness than to hormone responsiveness. The mRNA of the 52K protease accumulates rapidly following estradiol treatment, as was shown by Northern blot analysis with cloned cDNA. The 52K cathepsin-D-like protease is the first example of a lysosomal protease induced by estrogens in cancer cells. Results obtained using different approaches suggest that two cysteinyl cathepsins are also related to cell transformation and invasiveness. It has been proposed that cathepsin-B is involved in breast cancer and metastatic melanoma, and its regulation by estrogen has been shown in the rat uterus. Cathepsin-L corresponds to the major excreted protein (MEP) whose synthesis and secretion are markedly increased by transformation of NIH 3T3 cells with Ki ras and are regulated by several growth factors. In addition to secreted autocrine growth factors and to other proteases (plasminogen activator, collagenase), lysosomal cathepsins may therefore play an important role in the process of tumor growth and invasion as long as their precursor is secreted abundantly.

Breast Neoplasms↗
PubMed1987

The estrogen-regulated 52K-cathepsin-D in breast cancer: from biology to clinical applications.

We have studied estrogen-regulated proteins in an attempt to understand the mechanism by which estrogens stimulate cell proliferation and mammary carcinogenesis. In estrogen receptor positive human breast cancer cell lines (MCF7, ZR75-1) estrogens specifically increase the production into the culture medium of a 52,000 daltons (52K) glycoprotein. Several high affinity monoclonal antibodies to the partially purified secretory 52K protein have allowed to purify to homogeneity this protein and its cellular processed products. The 52K protein has been identified as the secreted precursor of a cathepsin-D like protease bearing mannose-6-phosphate signals and routed to lysosomes via mannose-6-phosphate receptor. The protease is mitogenic in vitro on estrogen deprived MCF7 cells and is able to degrade basement membrane and proteoglycans following its activation. The cellular related proteins, as detected by immunohistochemistry and immunoassay are more concentrated in proliferative mammary ducts than in resting ducts and their concentration in breast cancer cytosol appears to be more correlated with lymph nodes invasion and disease free survival (with S. Thorpe, Copenhagen) than with the estrogen receptor (RE) level. The protein is also produced constitutively by RE-negative cell lines, while in some antiestrogen resistant variants, it becomes inducible by tamoxifen, contrary to the wild type MCF7 cells. Cloning of its cDNA in lambda gt11 has allowed to show that the mRNA is rapidly induced by estrogens and to sequence the protein and compare it to that of the normal human kidney cathepsin-D.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1987

Phosphorylation, glycosylation, and proteolytic activity of the 52-kD estrogen-induced protein secreted by MCF7 cells.

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.

Breast Neoplasms↗
PubMed1986

The 52-kDa estrogen-induced protein secreted by MCF7 cells is a lysosomal acidic protease.

An estrogen-induced 52-kDa glycoprotein secreted by human breast cancer cells and able to autostimulate the growth of MCF7 cells has been purified, using monoclonal antibodies, and characterized. The protein contains mannose 6-phosphate signals on its N-linked high-mannose chains, suggesting that it is a lysosomal enzyme. Both the secreted 52-kDa protein and its processed cellular forms (52-, 48- and 34-kDa) were identified as carboxyl proteinases having an optimal activity at pH 3.5 and being specifically inhibited by pepstatin. This protease is characterized by its inducibility by estrogens and its high concentration in proliferative benign and malignant mammary tissue, when detected by immunohistochemistry. The estrogen-induced secretion of this protease may help to understand how estrogens stimulate mammary tumor growth and/or invasion.

Antibodies, Monoclonal↗
PubMed1986

Processing and estrogen regulation of the 52-kilodalton protein inside MCF7 breast cancer cells.

A 52K glycoprotein is secreted by human breast cancer cells in culture after estrogen stimulation. Using monoclonal antibodies, we have quantitated and characterized the corresponding proteins of the cell compartment. Using pulse-chase experiments, we have shown that about 40% of the 52K protein is secreted, the majority being successively processed into a 48K and a 34K protein. This last protein is very stable. The processing is inhibited by lysosomotropic agents and leupeptin, suggesting that it occurs in acidic vesicles, such as lysosomes or endosomes. Estradiol increased the intracellular level of immunoreactive 52K related proteins by 4-fold. Its effect is, however, more obvious in the medium, since there is a constitutive level in the cell. The stimulatory effects of estradiol on [3H]mannose and [35S]methionine incorporation into these proteins were similar and the endoglycosydase H sensitivity of the proteins was not altered, suggesting that estradiol did not modulate the glycosylation step. Antiestrogens did not stimulate synthesis and glycosylation of the 52K related proteins. Estradiol also increased the stability of the 52K precursor as well as that of total proteins. We conclude that the secreted 52K protein is the precursor of two cellular proteins of 48K and 34K. Estradiol stimulates both the intracellular accumulation of these proteins and the secretion of the precursor.

Ammonium Chloride↗