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P Basset

Publications and source records attributed to P Basset.

At least 37 records · Page 2Linked to original sources
PubMed1998

Membrane type-1 matrix metalloprotease and stromelysin-3 cleave more efficiently synthetic substrates containing unusual amino acids in their P1' positions.

The influence of the substrate P1' position on the specificity of two zinc matrix metalloproteases, membrane type-1 matrix metalloprotease (MT1-MMP) and stromelysin-3 (ST3), was evaluated by synthesizing a series of fluorogenic substrates of general formula dansyl-Pro-Leu-Ala-Xaa-Trp-Ala-Arg-NH2, where Xaa in the P1' position represents unusual amino acids containing either long arylalkyl or alkyl side chains. Our data demonstrate that both MT1-MMP and ST3 cleave substrates containing in their P1' position unusual amino acids with extremely long side chains more efficiently than the corresponding substrates with natural phenylalanine or leucine amino acids. In this series of substrates, the replacement of leucine by S-para-methoxybenzyl cysteine increased the kcat/Km ratio by a factor of 37 for MT1-MMP and 9 for ST3. The substrate with a S-para-methoxybenzyl cysteine residue in the P1' position displayed a kcat/Km value of 1.59 10(6) M-1 s-1 and 1.67 10(4) M-1 s-1, when assayed with MT1-MMP and ST3, respectively. This substrate is thus one of the most rapidly hydrolyzed substrates so far reported for matrixins, and is the first synthetic peptide efficiently cleaved by ST3. These unexpected results for these two matrixins suggest that extracellular proteins may be cleaved by matrixins at sites containing amino acids with unusual long side chains, like those generated in vivo by some post-translational modifications.

Amino Acids↗
PubMed1998

Identification and in situ hybridization mapping of a mouse Tpd52l1 (D53) orthologue to chromosome 10A4-B2.

We report the identification of a mouse cDNA Tpd52l1 (tumor protein D52-like 1), which represents the first demonstrated orthologue of the human TPD52L1 (alias D53) gene, a member of the breast carcinoma-associated TPD52 (alias D52) gene family. In situ hybridization mapping located the Tpd52l1 gene to chromosome 10A4-10B2. Since the TPD52L1 gene is found at human chromosome 6q22-->q23, the mouse and human TPD52L1 loci are syntenically conserved.

Amino Acid Sequence↗
PubMed1998

[Extracellular proteases of stromal origin: contribution to tumor progression and therapeutic perspectives].

For a long time, extracellular proteinases were thought to be expressed by the cancerous cells and only able to cleave extracellular matrix components, in order to promote tumor cell invasion. Recent works have now demonstrated that these proteinases are currently synthesized by stromal fibroblastic cells and that some of them may exhibit additive function(s). These findings lead to a new therapeutical concept leading to target the activity of stromal proteinases, and most notably of the matrix metalloproteinases.

Endopeptidases↗
PubMed1997

Expression of PACE4 in chemically induced carcinomas is associated with spindle cell tumor conversion and increased invasive ability.

Gene expression changes associated with the conversion of squamous cell carcinoma (SCC) to a more advanced malignant spindle cell carcinoma (SPCC) were determined by differential display. Using an animal model of human SCC progression, we provide evidence of increased PACE4 expression in SPCC cell lines and primary tumors induced by chemical carcinogenesis protocols, thus implicating this proprotein convertase in the process of tumor progression. Exogenous overexpression of PACE4 cDNA in mouse SCC cells of low invasive ability resulted in enhanced tumor cell invasiveness that was absent in parental or mock-transfected SCC cells. In addition, the PACE4-transfected cells acquired the ability to process prostromelysin 3 into its active enzyme form. Taken together, these results show that up-regulation of PACE4 expression is associated with SCC conversion to SPCC and suggests that activation of essential PACE4 substrates, such as the metalloproteinase stromelysin 3, is required for tumor cell invasion.

Animals↗
PubMed1997

Modulation of human stromelysin 3 promoter activity and gene expression by human breast cancer cells.

The matrix-degrading enzyme family of matrix-metalloproteinases (MMPs) has been implicated in the process of tumour metastasis. Cellular protein and RNA localisation techniques have been used to show that, whilst several MMP genes are expressed in both cancer and stromal cells, stromelysin 3 is expressed only in stromal fibroblasts adjacent to cancer cells. Immunohistochemical and in situ hybridisation evidence suggests that neoplastic cells can stimulate stromal cell MMP production either in a paracrine fashion or by a cell-cell contact mechanism. Using 2 different lengths of the human stromelysin 3 (ST3) gene 5' flanking sequence cloned upstream of luciferase and CAT reporter genes, we now show that human breast cancer cells can directly activate the ST3 promoter. The putative response element in the ST3 promoter, which lies between 0.46 and 3.4 kb upstream of the transcription start site, is able to effect a 2- to 3-fold increase in downstream gene expression. We further show that this transcriptional up-regulation definitely occurs via a paracrine, and possibly via a cell-cell contact, mechanism. Confirmation that this ST3 promoter activation results in ST3 gene induction of a similar magnitude was shown using Northern blotting of stimulated fibroblasts. Our data provide further evidence that cancer cells can induce fibroblast MMP expression and help to explain the in vivo expression pattern of ST3 in breast cancer.

3T3 Cells↗
PubMed1997

Stromelysin-3 induction and interstitial collagenase repression by retinoic acid. Therapeutical implication of receptor-selective retinoids dissociating transactivation and AP-1-mediated transrepression.

Human stromelysin-3 and interstitial collagenase are matrix metalloproteinases whose expression by stromal cells in several types of carcinomas has been associated with cancer progression. We compared here the regulation of the expression of both proteinases by retinoids in human fibroblasts. Physiological concentrations of retinoic acid were found to simultaneously induce stromelysin-3 and repress interstitial collagenase. In both cases, the involvement of a transcriptional mechanism was supported by run-on assays. Furthermore, in transient transfection experiments, the activity of the stromelysin-3 promoter was induced by retinoic acid through endogenous receptors acting on a DR1 retinoic acid-responsive element. The ligand-dependent activation of the receptors was also investigated by using selective synthetic retinoids, and we demonstrated that retinoic acid-retinoid X receptor heterodimers were the most potent functional units controlling both stromelysin-3 induction and interstitial collagenase repression. However, specific retinoids dissociating the transactivation and the AP-1-mediated transrepression functions of the receptors were found to repress interstitial collagenase without inducing stromelysin-3. These findings indicate that such retinoids may represent efficient inhibitors of matrix metalloproteinase expression in the treatment of human carcinomas.

Carcinoma↗
PubMed1997

MLN64 exhibits homology with the steroidogenic acute regulatory protein (STAR) and is over-expressed in human breast carcinomas.

The MLN64 gene, which is localized in q12-q21 of the human chromosome 17, encodes a novel protein containing 2 distinct domains. At the N-terminal, MLN64 exhibits a potential trans-membrane region, while at the C-terminal, it shares homology with the F26F4.4 protein of Coenorhabditis elegans and the steroidogenic acute regulatory (StAR) protein, a mitochondrial protein which is involved in steroid-hormone synthesis. By comparing the C-terminal part of these proteins, we defined a novel protein domain, which we termed SHD for "StAR Homology Domain". Of the 93 primary invasive breast carcinomas that were examined, 14 were found to over-express MLN64. These 14 tumors also expressed high c-erbB-2 transcript levels, which were not detected in the MLN64-negative tumors. MLN64 mRNA and protein were specifically detected in malignant cells of breast carcinomas. MLN64 protein was localized within bundle-like structures distributed throughout the cell cytoplasm and condensed in a perinuclear patch, suggesting an association with a specific cell compartment. When the N-terminal part of MLN64 was deleted, MLN64 was uniformly distributed in the cell cytoplasm, indicating that N-terminal part is involved in the specific cytoplasmic localization of MLN64. The homology between the C-terminal part of MLN64 and the functional StAR domain (SHD) suggests that MLN64 and StAR, although distributed in different cellular compartments, may both play a role in steroidogenesis. In this case, the high levels of MLN64 observed in some breast carcinomas could contribute to the progression of these tumors through increased intratumoral steroidogenesis.

Amino Acid Sequence↗
PubMed1997

Expression of matrix metalloproteinases during rat skin wound healing: evidence that membrane type-1 matrix metalloproteinase is a stromal activator of pro-gelatinase A.

Skin wound healing depends on cell migration and extracellular matrix remodeling. Both processes, which are necessary for reepithelization and restoration of the underlying connective tissue, are believed to involve the action of extracellular proteinases. We screened cDNA libraries and we found that six matrix metalloproteinase genes were highly expressed during rat skin wound healing. They were namely those of stromelysin 1, stromelysin 3, collagenase 3, gelatinase A (GelA), gelatinase B, and membrane type-1 matrix metalloproteinase (MT1-MMP). The expression kinetics of these MMP genes, the tissue distribution of their transcripts, the results of cotransfection experiments in COS-1 cells, and zymographic analyses performed using microdissected rat wound tissues support the possibility that during cutaneous wound healing pro-GelA and pro-gelatinase B are activated by MT1-MMP and stromelysin 1, respectively. Since MT1-MMP has been demonstrated to be a membrane-associated protein (Sato, H., T. Takino, Y. Okada, J. Cao, A. Shinagawa, E. Yamamoto, and M. Seiki. 1994. Nature (Lond.). 370: 61-65), our finding that GelA and MT1-MMP transcripts were expressed in stromal cells exhibiting a similar tissue distribution suggests that MT1-MMP activates pro-GelA at the stromal cell surface. This possibility is further supported by our observation that the processing of pro-GelA to its mature form correlated to the detection of MT1-MMP in cell membranes of rat fibroblasts expressing the MT1-MMP and GelA genes. These observations, together with the detection of high levels of the mature GelA form in the granulation tissue but not in the regenerating epidermis, suggest that MT1-MMP and GelA contribute to the restoration of connective tissue during rat skin wound healing.

Animals↗
PubMed1997

Rat stromelysin 3: cDNA cloning from healing skin wound, activation by furin and expression in rat tissues.

From a rat skin wound healing cDNA library, a clone encoding stromelysin 3 (ST3) was isolated. The predicted rat ST3 has 491 amino acids, and shows 83, 95 and 58% homology with human, mouse and Xenopus ST3, respectively. COS-1 cells transfected with this rat ST3 cDNA produced the ST3 proform, which could be converted to the mature ST3 form by co-transfection with rat furin cDNA. In addition to healing skin, the rat ST3 gene was found to be strongly expressed in normal adult uterus and ovary, and at lower levels in chemically-induced mammary tumors.

Amino Acid Sequence↗
PubMed1997

Matrix metalloproteinases as stromal effectors of human carcinoma progression: therapeutic implications.

The matrix metalloproteinases (MMPs) are extracellular zinc-enzymes implicated in a number of physiological and pathological tissue remodeling processes, including cancer progression. For a long time they have been thought to be produced by malignant cells and to specifically contribute to tumor invasion, through their ability to degrade extracellular matrix components. However, studies performed over the last few years have demonstrated that extracellular proteinases implicated in the progression of human carcinomas, including most MMPs, are in fact predominantly expressed by stromal and not by cancer cells. Furthermore, membrane receptors, activators and/or binding sites for some of these proteinases are also predominantly found to be associated with stromal cells. These findings, together with the observation that MMPs can cleave some molecules implicated in controlling growth factor activities, suggest that the role of MMPs during cancer progression is not limited to facilitating malignant cell invasion alone but is also likely to participate in other aspects of the malignant phenotype. MMPs should in fact be regarded as pan-regulators of tissue neoformation characteristic of malignant tumors, which includes both epithelial cell expansion and stroma formation. In this context, synthetic MMP inhibitors which are presently designed should lead to the development of a new generation of anticancer agents with additional beneficial properties compared to the existing cytotoxic agents used in the treatment of human malignancies.

Extracellular Matrix↗
PubMed1996

High levels of stromelysin-3 correlate with poor prognosis in patients with breast carcinoma.

Stromelysin 3 (ST3) is a matrix metalloprotease (MMP) expressed in fibroblast-like cells of most human invasive carcinomas. In this investigation, ST3 was measured by semiquantitative immunohistochemistry in 111 primary breast cancers. ST3 levels showed no correlation with tumor size, axillary-node status or tumor grade (Scarff-Bloom-Richardson system; SBR) but were significantly associated with higher nuclear grade (modified SBR). In addition, ST3 levels were significantly higher in ductal than in lobular cancers. Patients with high scores of ST3 staining had a shorter disease-free interval and shorter overall survival than patients with low scores. ST3 is thus one of the first MMPs to correlate with patient outcome in breast cancer. These findings are consistent with earlier clinical and experimental observations suggesting that ST3 contributes to breast-cancer progression.

Biomarkers, Tumor↗
PubMed1996

Definition of the tumor protein D52 (TPD52) gene family through cloning of D52 homologues in human (hD53) and mouse (mD52).

Cloning is reported of a cDNA homologue to the breast carcinoma-associated D52 cDNA, termed D53, and of a mouse D52 cDNA (HGMW-approved symbols TPD52L1 and TPD52). Human D53 and mouse D52 proteins are predicted to be 52 and 86% identical to human D52, respectively. Analysis of the three protein sequences identified a coiled-coil domain and N- and C-terminally located PEST domains in each. The conservation of homology between the D52 and the D53 sequences, combined with a lack of homology between these and known proteins, defines a new mammalian gene/protein family, the D52 family. The human D52 locus has been previously mapped to chromosome 8q21, and using in situ mapping in the present study, a human D53 locus was mapped to chromosome 6q22-q23. We observed coexpression of the human D52 and D53 genes in some breast tumors and derivative cell lines and found that maintenance of D52 and D53 transcript levels in estrogen receptor-positive MCF7 breast carcinoma cells depends upon estradiol. However, D52 and D53 genes were specifically expressed in HL-60 and K-562 leukemia cells, respectively, with 12-O-tetra-decanoylphorbol-13-acetate treatment decreasing D52 and D53 transcript levels in these cell lines. The presence of a coiled-coil domain, combined with observed co- or independent expression of the D52 and D53 genes, suggests that D52 and D53 proteins may be capable of hetero- and/or homodimer formation.

Amino Acid Sequence↗
PubMed1996

Characterization of structural determinants and molecular mechanisms involved in pro-stromelysin-3 activation by 4-aminophenylmercuric acetate and furin-type convertases.

Stromelysin-3 (ST3) is a matrix metalloproteinase (MMP) which has been implicated in cancer progression and in a number of conditions involving tissue remodelling. In contrast to other MMPs which are secreted as zymogens requiring extracellular activation, ST3 is found in the extracellular space as a potentially active mature form, suggesting that the activation of the ST3 proform differs from that of other MMPs. We show in the present study that the ST3 proform is not autocatalytically processed in the presence of 4-aminophenylmercuric acetate (APMA). By using ST3/ST2 chimeras, we demonstrate that resistance to APMA is due to properties associated with both the ST3 pro- and catalytic domains. In agreement with the observation made by Pei and Weiss [Pei and Weiss (1995) Nature (London) 375, 244-247], we find that the requirement for activation of the ST3 proform by the furin convertase is entirely contained within a stretch of 10 amino acids located at the junction between the ST3 pro- and catalytic domains. Furin cleaves human and mouse ST3 equally well. However, PACE-4, a furin-like convertase, is much more efficient on the mouse enzyme, suggesting that ST3 protein determinants other than the conserved Ala-Arg-Asn-Arg-Gln-Lys-Arg sequence preceding the furin cleavage site are implicated in PACE-4 action. Finally, we show that processing of the ST3 proform is inhibited by a furin inhibitor in human MCF7 breast cancer cells stably transfected to constitutively express a full-length human ST3 cDNA. Using brefeldin A, we demonstrate that, in these MCF7 cells, the 56 kDa precursor form of ST3 is post-translationally modified in the cis- or media-Golgi into a 62 kDa proform. Thereafter, its processing into the 47 kDa mature form occurs in the trans-Golgi network and is followed by secretion into the extracellular space.

Amino Acid Sequence↗
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↗
PubMed1995

The cDNA cloning and expression of the gene encoding rat gelatinase B.

During a study aimed at defining the role of tissue remodeling genes implicated in wound healing, we isolated cDNA clones encoding gelatinase B (GelB) from a cDNA library derived from healing rat skin wound. The predicted rat GelB comprising 708 amino acids shows 75% and 82% identity with the human and mouse GelB, respectively. By Northern blot analysis, two GelB transcripts of 2.4 and 3.0 kb were observed in rat tissues, and shown to arise through the differential use of polyadenylation signals. Recombinant rat pro-GelB produced in transfected COS-1 cells exhibited a molecular weight of 92 kDa, as shown by gelatin zymography. Autocatalytic processing to active lower-molecular-weight forms was induced by 4-aminophenylmercuric acetate, and this process was inhibited in the presence of EDTA.

Amino Acid Sequence↗