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Biomedical subjects

M C Rio

Publications and source records attributed to M C Rio.

At least 55 records · Page 3Linked to original sources
PubMed1997

[What is/are the function(s) of trefoil peptides?].

pS2, SP and ITF have been identified in the eighties. These peptides share a consensus proteic domain including 3 disulfide bridges leading to a 3 loop structure and subsequently to their name of trefoil peptides. While they are normally expressed in restricted parts of the gastrointestinal tract, ectopic expression is also observed during gastrointestinal ulcerations and in various carcinomas. To date, from numerous studies performed in vitro and in vivo, their functions in these pathologies begin to be elucidated.

Animals↗
PubMed1996

Gastric mucosa abnormalities and tumorigenesis in mice lacking the pS2 trefoil protein.

To determine the function of the pS2 trefoil protein, which is normally expressed in the gastric mucosa, the mouse pS2 (mpS2) gene was inactivated. The antral and pyloric gastric mucosa of mpS2-null mice was dysfunctional and exhibited severe hyperplasia and dysplasia. All homozygous mutant mice developed antropyloric adenoma, and 30 percent developed multifocal intraepithelial or intramucosal carcinomas. The small intestine was characterized by enlarged villi and an abnormal infiltrate of lymphoid cells. These results indicate that mpS2 is essential for normal differentiation of the antral and pyloric gastric mucosa and may function as a gastric-specific tumor suppressor gene.

Adenoma↗
PubMed1996

Two distinct amplified regions at 17q11-q21 involved in human primary breast cancer.

Chromosomal segment 17q11-q21 is a commonly amplified region in human breast carcinomas. Several lines of evidence suggest that ERBB2 is the gene responsible for the emergence of this amplicon, but four novel genes (called MLN 50, MLN 51, MLN 62, and MLN 64) in 17q11-q21 have recently been found to be amplified and overexpressed in breast cancer cell lines. We investigated 98 primary breast tumors for amplification of these five loci. Twenty-five tumors (25.5%) showed amplification of at least one of these markers, but most amplifications did not encompass all of the tested loci. The genes most frequently amplified were ERBB2 and MLN 64 (22 of 25 amplified cases). MLN 64 was always coamplified with ERBB2, and to a similar level. Amplification of these five genes always leads to overexpression of their mRNA; we observed no cases of overexpression without amplification in any of these genes. Our results suggest that: (a) an independent, amplified region defined by MLN 62 (also called CART1 or TRAF4) is located in 17q11-q12; (b) in addition to ERBB2, MLN 64 is a major target for the 17q12-q21 amplicon; and (c) these MLN genes could be of pathogenetic significance in breast cancer.

Breast Neoplasms↗
PubMed1996

Stromelysin-3 expression promotes tumor take in nude mice.

Stromelysin-3 (ST3) is a matrix metalloproteinase expressed in human carcinomas in ways suggesting that it may play a role in tumor progression. To test this possibility, we have performed gene transfer experiments using both anti-sense and sense ST3 expression vectors, and malignant cells either expressing (NIH 3T3 fibroblasts) or not (MCF7 epithelial cells) endogenous ST3. We have compared the ability of parental and transfected cells to cause subcutaneous tumor development in nude mice. 3T3 cells expressing anti-sense ST3 RNA showed reduced tumorigenicity, and MCF7 cells expressing mouse or human ST3 were associated with reduced tumor-free period leading to a significant increased tumor incidence(P<10(-4)). However, once established, the ST3 expressing tumors did not grow faster than those obtained with the parental MCF7 cell line. In addition, tumors obtained after sub-cutaneous injection of ST3-expressing or nonexpressing cells did not exhibit obvious histological differences, and careful examination did not reveal any local invasive tissue areas nor systemic metastases. These in vivo observations were in agreement with those obtained in vitro showing that ST3 expression did not modify proliferative nor invasive properties of transfected cells. Altogether, these results indicate that ST3 expression promotes tumor take in nude mice, presumably by favoring cancer cell survival in a tissue environment initially not permissive for tumor growth. These findings represent the first experimental evidence showing that ST3 can modulate cancer progression.

3T3 Cells↗
PubMed1996

Stromelysin-3 in the biology of the normal and neoplastic mammary gland.

Stromelysin-3 (ST3) is an extracellular proteinase predominantly expressed in fibroblasts. The particular structural features and in vitro functions of this molecule suggest it could be the first member of a new subgroup of the matrix metalloproteinase family. ST3 is transiently expressed during mammary gland post-weaning involution, embryonic implantation, various organogeneses, and during amphibian metamorphosis. Moreover, ST3 is expressed in a panel of human invasive carcinomas including breast, colon, and head and neck carcinomas. Almost all ST3-expressing tissues show intense extracellular matrix remodeling activities including the loss of basement membrane integrity. Thus, either directly, or indirectly in association with other proteinases, ST3 might be involved in tissue remodeling processes occurring in both physiological and pathological processes. In vitro and in vivo studies using malignant cells stably transfected in such a way as to modulate their ST3 expression levels indicate that ST3 modifies neither cell proliferation nor invasive properties, but rather favors tumor cell survival in host tissues. This hypothesis is consistent with clinical data showing that ST3 expression could be predictive of tumor progression leading to metastases.

Animals↗
PubMed1996

Defective tumor vascularization induced by metastasin 1 expression.

It has been proposed that metastasin 1 (mts1), a member of the S100 Ca(2+)-binding protein family, may play a role in tumor progression and metastasis. In order to test this possibility, we have performed gene transfer experiments using a human sense mts1 expression vector and human MCF7 malignant epithelial cells which do not express endogenous mts1. In vitro, mts1 expression did not modify proliferative or invasive properties of transfected MCF7 cells. In vivo, MCF7 cells expressing mts1 were associated with tumors exhibiting necrosis, and abundant fibrous and poorly cellular stroma. Immunohistochemical staining of endothelial cells showed that, in the presence of mts1, the number and the size of tumoral microvessels were decreased and some of them were collapsed. No metastases were observed in mice with either mts1-expressing or nonexpressing tumors. In summary, these results indicate that (i) in vitro and in vivo, mts1 does not confer invasive properties to MCF7 cells, and (ii) mts1 expression by MCF7 cells leads to defective tumor microvessels, leading to the hypothesis that mts1 may have a negative effect on neoangiogenesis and/or on the maintenance of blood vessels.

Animals↗
PubMed1995

Presence of a new conserved domain in CART1, a novel member of the tumor necrosis factor receptor-associated protein family, which is expressed in breast carcinoma.

CART1, a novel human gene, encodes a putative protein exhibiting three main structural domains: first, a cysteine-rich domain located at the amino-terminal part of the protein, which corresponds to an unusual RING finger motif; second, an original cysteine-rich domain located at the core of the protein and constituted by three repeats of an HC3HC3 consensus motif that we designated the CART motif, and which might interact with nucleic acid; third, the carboxyl-terminal part of the CART1 protein corresponds to a TRAF domain known to be involved in protein-protein interactions. Similar association of RING, CART, and TRAF domain was observed in the human CD40-binding protein and in the mouse tumor necrosis factor (TNF) receptor-associated factor 2 (TRAF2), both involved in signal transduction mediated by the TNF receptor family and in the developmentally regulated Dictyostelium discoideum DG17 protein. CART1 is specifically expressed by epithelial cells in breast carcinomas and metastases. Moreover, in these malignant cells, the CART1 protein is localized in the nucleus. Altogether, these observations indicate that CART1 may be involved in TNF-related cytokine signal transduction in breast carcinoma.

Amino Acid Sequence↗
PubMed1995

Characterization of monoclonal antibodies against stromelysin-3 and their use to evaluate stromelysin-3 levels in breast carcinoma by semi-quantitative immunohistochemistry.

Stromelysin-3 (ST3) is a matrix metalloproteinase which is expressed in fibroblastic cells of most human invasive carcinomas and represents a potential new prognostic indicator. Expression of recombinant ST3 forms in Escherichia coli from cDNA constructs indicated that high levels of expression were achieved when the ST3 pro-domain was deleted. The putative mature form of ST3 thus produced and recovered from bacterial inclusion bodies was used to prepare monoclonal antibodies (MAbs) against ST3 by immunization of BALB/C mice. Ten hybridomas producing MAbs against ST3 were obtained and analyzed for their ability to detect endogenous ST3 in breast cancer and in conditioned media from human fibroblasts. One of these MAbs (5ST-4A9) was found to be suitable for the routine detection of ST3 on breast cancer tissue sections, thus opening the possibility to evaluate ST3 prognostic value in breast cancer using semi-quantitative immunohistochemistry.

Animals↗
PubMed1995

Lasp-1 (MLN 50) defines a new LIM protein subfamily characterized by the association of LIM and SH3 domains.

MLN 50 was previously identified in a cDNA library of breast cancer metastasis. In this study, we show that MLN 50, which is expressed at a basal level in normal tissues, is overexpressed in 8% of human breast carcinomas most often together with c-erbB-2. MLN 50 cDNA encodes a putative protein of 261 residues, named Lasp-1 (LIM and SH3 protein) since it contains a LIM motif and a domain of Src homology region 3 (SH3) at the amino- and the C-terminal parts of the protein, respectively. Thus, Lasp-1 defines a new LIM protein subfamily.

Adaptor Proteins, Signal Transducing↗
PubMed1995

Comparative expression of the psoriasin (S100A7) and S100C genes in breast carcinoma and co-localization to human chromosome 1q21-q22.

Using differential screening of a breast cancer cDNA library, we isolated a cDNA encoding the psoriasin (S100A7) protein, previously identified in psoriatic epidermis. In the present study, we demonstrate that the psoriasin gene is expressed in breast cancer cell lines and in cancer cells of some breast carcinomas but not in any non-cancerous tissues examined, except skin. Another S100 gene, S100C, which we co-localized with the psoriasin gene to human chromosome 1q21-q22, was found to be expressed in most tissues and cell lines evaluated. These findings add support to the concept that the S100 genes clustered in human chromosome 1q21-q22 are individually controlled and that some of them may be involved in the regulation of cell transformation and/or differentiation.

Amino Acid Sequence↗
PubMed1995

Identification of structural determinants controlling human and mouse stromelysin-3 proteolytic activities.

Matrix metalloproteinases (matrixins) constitute a group of extracellular proteinases belonging to the metzincin superfamily. They are involved in both physiological and pathological tissue remodeling processes, including those associated with cancer progression. Stromelysin-3, which is expressed in most invasive human carcinomas, is a matrix metalloproteinase with unusual functional properties. In particular, its mature form does not cleave any of the major extracellular matrix components. To define critical structural determinants involved in controlling stromelysin-3 proteolytic activity, we have used site-directed mutagenesis. We show that the deletion of at least 175 C-terminal amino-acids is sufficient to endow mouse stromelysin-3 with activities against casein, laminin, and type IV collagen. In the case of the human enzyme, however, a further and single Ala-235-->Pro substitution is necessary to observe similar activities. Ala-235, which characterizes human stromelysin-3 among matrixins, is located immediately after the C terminus of the "Met-turn," which forms a hydrophobic basis for the catalytic zinc atom in the metzincin family. We conclude that human stromelysin-3 has gained specific functional properties during evolution by amino acid substitution in the catalytic zinc environment, and that it represents an attractive target for specific inhibitors that may be used to prevent cancer progression.

Alanine↗
PubMed1995

Identification of four novel human genes amplified and overexpressed in breast carcinoma and localized to the q11-q21.3 region of chromosome 17.

We have performed differential screening of a human metastatic lymph lymph node cDNA library to identify genes possibly involved during breast cancer progression. We have identified four novel genes overexpressed in malignant tiddues. They were all located on the long arm of chromosome 17, in loci located between q11 and q21.3, a region known to contain the c-erbB-2 oncogene and the BRCA1 breast carcinomas, and overexpression of three of them was dependent on gene amplification in breast cancer cell lines. These findings further support the concept that human chromosome 17 specifically carries genes possibly involved in breast cancer progression.

Adult↗
PubMed1995

A screening method to identify genes commonly overexpressed in carcinomas and the identification of a novel complementary DNA sequence.

We describe a differential screening method for cDNA libraries which used a combination of subtracted and PCR-amplified cDNA probes, and which can be applied to the selection of genes expressed in multiple tissues. This technique was used to identify genes commonly overexpressed in breast and basal cell carcinomas. These represent stromally dependent, invasive tumors with and without metastatic capacity. Thus, this screening sought to identify genes involved in the early stages of tumor progression. We identified a total of 16 genes, including c-erbB-2 and tissue inhibitor of metalloproteinases 3 whose products have been implicated in tumorigenesis or invasion. We also identified a novel sequence (D52) showing little homology with others described in any species, which maps to the human chromosomal band 8q21. In situ RNA hybridizations of breast carcinoma sections indicated that the D52 gene was expressed in cancer cells, whereas other genes identified in the differential screening were expressed in fibroblastic or inflammatory cells within the tumor stroma. Thus, the procedure developed in this study selected genes expressed in a diversity of cell types, indicating its potential usefulness in other systems.

Amino Acid Sequence↗
PubMed1995

Genomic sequencing indicates a correlation between DNA hypomethylation in the 5' region of the pS2 gene and its expression in human breast cancer cell lines.

The methylation status of the cytosines located on the 5' region of the pS2 gene have been investigated in two human breast cancer cell lines. The genomic sequencing method used is based on an oxydative deamination by NaHSO3 of the unmethylated cytosines, but not 5-methylcytosine. Data obtained indicate that in the DNA extracted from the pS2-expressing cell line, MCF7, the CpG located at the 5' flanking sequence of pS2 are unmethylated. In contrast in the non-expressing cell line, BT20, these CpG are largely methylated. However, this correlation is not observed at all CpG sites, since a significant portion of the cloned PCR fragments obtained from BT20 cells are unmethylated at specific CpG sites. These results suggest that the methylation status of only some of the CpG located at the 5' flanking sequences of pS2 might differ between expressing and nonexpressing cell lines.

Base Sequence↗
PubMed1995

Membrane-type matrix metalloproteinase (MT-MMP) gene is expressed in stromal cells of human colon, breast, and head and neck carcinomas.

From breast cancer cDNA libraries, we have cloned cDNAs that proved to correspond to the membrane-type matrix metalloproteinase (MT-MMP) recently identified in human placenta and proposed to be an activator of progelatinase A [Sato, H., Takino, T., Okada, Y., Cao, J., Shinagawa, A., Yamamoto, E. & Seiki, M. (1994) Nature (London) 370, 61-65]. Using one of these cDNAs as a probe, we have detected MT-MMP gene expression in all 83 human carcinoma specimens examined by RNA in situ hybridization and have found MT-MMP transcripts in fibroblastic cells of tumor stroma but not in cancer cells. Comparison with other MMP genes expressed in fibroblastic cells of human carcinomas indicated that the expression pattern of the MT-MMP gene was more closely related to that of the gelatinase A gene than to those of the stromelysin 3 or interstitial collagenase genes. These observations are consistent with the hypothesis that MT-MMP and gelatinase A are cooperating during tumor progression and strengthen the concept that proteolytic activities originating from the stromal component of human carcinomas have a critical role in tumor progression.

Adenocarcinoma↗
PubMed1995

Developmental expression of mouse stromelysin-3 mRNA.

We have used northern blot analysis and in situ hybridization to study the spatial distribution of stromelysin-3 (ST3) expression during mouse embryogenesis. ST3 mRNA was observed in trophoblastic cells at the site of embryonic implantation (7.5-8.5 days) and in a variety of developing embryonic tissues. In these tissues, the highest ST3 expression levels were observed during the development of the external features of limb, tail and snout, and during bone and spinal cord morphogenesis. In limb, tail and snout, ST3 expression was specifically detected in mesenchymal cells lining the basement membrane at the junction of primitive dermis and epidermis, and adjacent to epithelial cells undergoing proliferation and/or apoptosis. In bone, ST3 was expressed in invasive mesenchymal cells and, in the spinal cord in neuroepithelial cells of the floor plate, at the time that this structure is crossed by commissural axons. Altogether, these observations suggest a role for ST3 during embryonic morphogenesis, in tissue remodeling processes associated with cell proliferation, death and/or invasion. Moreover, when compared to urokinase and tissue plasminogen activators, the spatiotemporal pattern of ST3 expression shows some similarities, but was not completely superimposable, suggesting that these genes may cooperate in some developing tissues and have specific functions in others.

Animals↗
PubMed1995

The tissue inhibitor of metalloproteinases-3 gene in breast carcinoma: identification of multiple polyadenylation sites and a stromal pattern of expression.

BACKGROUND: Tissue inhibitor of metalloproteinases-3 (TIMP3) is the third member of the TIMP family of proteins, believed to play a significant role in controlling extracellular matrix remodeling. MATERIALS AND METHODS: Differential screening of a human breast carcinoma cDNA library using substracted and PCR-amplified cDNA probes identified a 4.6-kb TIMP3 cDNA, which was used for further cDNA library screenings, Northern blot hybridizations, and the synthesis of riboprobes for in situ RNA hybridization analyses. RESULTS: The 4.6-kb full-length TIMP3 cDNA contains 3.7 kb of 3'-untranslated sequence. Additional TIMP3 cDNAs subsequently identified were colinear with the original sequence, but revealed use of four different polyadenylation signals within the 3'-untranslated region, which accounted for the 4.6-, 2.7-, 2.5-, and 2.1-kb TIMP3 transcripts noted in this and in previous studies. In situ RNA hybridizations demonstrated that in breast carcinoma the TIMP3 gene was predominantly expressed by fibroblastic cells within the tumor stroma adjacent to cancer cells. TIMP3 transcripts were also strongly detected in fibroblastic decidual cells of pregnant endometrium. CONCLUSIONS: Modulating the length of the 3'-untranslated region may represent a mechanism by which TIMP3 gene expression is controlled in tissues. The strong expression of the TIMP3 gene by fibroblastic cells in breast carcinoma supports the importance of tumor stroma as a source of factors influencing human carcinoma growth and progression.

Breast Neoplasms↗