Presence of active gelatinases in endometrial carcinoma and correlation of matrix metalloproteinase expression with increasing tumor grade and invasion

BACKGROUND

The actions of the extracellular-matrix degrading enzymes, matrix metalloproteinases (MMPs), are implicated in tumorigenesis. The cellular localization of MMP-2, MMP-9, membrane type 1 (MT1)-MMP, tissue inhibitors of metalloproteinases (TIMPs) 1-3, and the presence of active gelatinases were investigated in endometrial carcinoma.

METHODS

Endometrial carcinomas were grouped according to histologic grade (Grades 1-3), depth of myometrial invasion (0, < 50%, > 50%) and the presence of vascular/lymphatic invasion. Twenty-nine endometrial carcinoma biopsies were investigated immunohistochemically to determine the tissue localization of MMP-2 (gelatinase A), MMP-9 (gelatinase B), MT1-MMP, and TIMPs 1-3. In situ hybridization was performed to localize MMP-2 and MMP-9 mRNA. The presence of active gelatinases was assessed using in situ zymography.

RESULTS

Epithelial tumor cells were the main site of MMP-2, MMP-9, and MT1-MMP protein. Variable stromal cell localization was also observed, particularly in areas adjacent to tumor nests. Semiquantitative analysis revealed increases in MMP-9 and MMP-2 but not MT1-MMP staining scores in tumor epithelial cells in the transition from histologic Grade 1 to Grades 2 and 3. Matrix metalloproteinase-9 and MT1-MMP staining scores in tumor cells were significantly associated with the presence of myometrial invasion and vascular/lymphatic invasion, while MMP-2 did not correlate with these factors. In addition, MT1-MMP was co-localized with MMP-2, supporting its role in the activation of proMMP-2. Tumor cells from all histologic grades stained intensely for TIMP-2 and TIMP-3 proteins, while variable stromal staining was observed. In Grade 1 carcinomas TIMP-1 was predominantly immunolocalized to the stromal compartment with variable tumor cell localization being observed in Grades 2 and 3 carcinomas. Matrix metalloproteinase-9 and MMP-2 mRNAs were predominantly observed in tumor epithelial cells as well as in the stroma to varying degrees. In situ zymography revealed active forms of gelatinases at the cellular surface and in association with tumor epithelial cells within endometrial carcinoma tissues.

CONCLUSIONS

These data suggest that increasing expression of MMPs and endometrial carcinoma progression are closely related. Active gelatinases are present in endometrial carcinoma, resulting in alterations to the microenvironment that promote tumor invasion and metastasis.

Overexpression of alpha(v)beta6 integrin in serous epithelial ovarian cancer regulates extracellular matrix degradation via the plasminogen activation cascade

Recent evidence suggests that integrins are involved in the multi-step process of tumour metastasis. The biological relevance of alpha(v) integrins and associated beta-subunits in ovarian cancer metastasis was examined by analysing the expression of these cell surface receptors in nine ovarian cancer cell lines and also in the primary human ovarian surface epithelial cell line (HOSE). beta1, beta3 and beta5 subunits were present in all ten ovarian cell lines. beta6 subunit was present at varying levels in eight out of nine cancer cell lines but was absent in the HOSE cell line. Immunohistochemical staining showed that beta6 was present in both non-invasive (borderline) and high-grade ovarian cancer tissues but was absent in benign and normal ovarian tissue. High alpha(v)beta6 integrin expressing ovarian cancer cell lines had high cell surface expression of uPA and uPAR. Ovarian cancer cell lines expressing high to moderate level of alpha(v)beta6 integrin demonstrated ligand-independent enhanced levels of high molecular weight (HMW)-uPA and pro-matrix metalloproteinase 2 and 9 (pro-MMP-2 and pro-MMP-9) expression in the tumour-conditioned medium. High and moderate expression of alpha(v)beta6 integrin correlated with increased plasminogen-dependent degradation of extracellular matrix which could be inhibited by inhibitors of plasmin, uPA and MMPs or by monoclonal antibody against uPA, MMP-9 or alpha(v)beta6 integrin. These results suggest that endogenous de novo expression of alpha(v)beta6 integrin in ovarian cancer cells may contribute to their invasive potential, and that alpha(v)beta6 expression may play a role in ovarian cancer progression and metastasis.

Activated matrix metalloproteinase-2--a potential marker of prognosis for epithelial ovarian cancer

OBJECTIVES AND METHODS

To investigate the relationship between the expression of matrix metalloproteinase-2 (MMP-2) and clinical characteristics in patients with epithelial ovarian tumors, we examined the expression of MMP-2 in 26 epithelial benign ovarian tumors (EBOT) and 41 epithelial ovarian carcinomas (EOC) using semi-quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry. We also analyzed pro-MMP-2 and activated MMP-2 in epithelial ovarian tumors using Western blot. RESULTS The expression levels of MMP-2 mRNA and overall protein were higher in EOC than in EBOT, but the differences were not statistically significant (P > 0.05). MMP-2 mRNA and immunoreactive protein for MMP-2 were not significantly associated with clinicopathological features in EOC. The positive percentages of the active form of MMP-2 were 71% in EOC and 42% in EBOT, respectively (P < 0.05). The positive percentage of the active form of MMP-2 in stage III and IV EOC was significantly higher (81%) than that (33%) in stage I and II EOC (P = 0.01). The expression of activated MMP-2 was significantly related to disease progression in EOC (P = 0.02). The percentages of active MMP-2 in positive immunoreaction tumor cells and fibroblasts were, respectively, 96 and 89%. The difference was not statistically significant (P = 0.54). The positive and negative predictive values of active MMP-2 for disease progression were 65 (19/29) and 75% (9/12), respectively, and the accuracy was 68% (28/41).

CONCLUSION

MMP-2 generally appears in epithelial ovarian tumors and there is a tendency to express more MMP-2, and especially activated MMP-2, in EOC. MMP-2 mRNA and pro-MMP-2 are not associated with the clinicopathological features in patients with EOC. There was a significant relationship between activated MMP-2 and invasiveness, metastasis, and disease progression in EOC and activated MMP-2 is a potential marker of prognosis.

Regulation of gelatinase-A (MMP-2) production by ovine intervertebral disc nucleus pulposus cells grown in alginate bead culture by Transforming Growth Factor-beta(1)and insulin like growth factor-I

The aim of this study was to gain information relevant to disc repair processes. Limited degradation of the collagen matrix by matrix metalloproteases (MMPs) may facilitate the loosening of cell-cell and cell-matrix interactions within the injured intervertebral disc (IVD) to favour the penetration of blood vessels and migration of fibroblasts into the defect to promote repair processes. Gelatinase A (MMP-2) has a particularly important role to play in angiogenesis, in the present study we investigated the in vitro regulation of MMP-2 by Transforming Growth Factor-beta 1 (TGF-beta 1) and Insulin-like Growth Factor-1 (beta IGF-I) in cells from the nucleus pulposus (NP) of the ovine IVD. Ovine NP cells were grown in alginate bead cultures in complete medium (10% foetal calf serum) for 7 days, established in serum-free conditions for 24 h, then stimulated with TGF-beta 1 (0.1 or 10 ng/ml) or IGF-I (2 or 50 ng/ml) +/-Concanavalin A (20 microg/ml) for an additional 48 h. Conditioned medium was examined for matrix metalloproteases using gelatin zymography, Tissue Inhibitor of Metalloproteinase 2 (TIMP-2) and Membrane Type 1 Matrix Metalloproteinase (MT1-MMP) were immunolocalised in beads. Pro (72 kDa) and active (59 kDa) MMP-2 were the major gelatinolytic MMPs detected in control cultures, the TGF-beta 1 and IGF-I treatments significantly decreased levels of the active MMP-2, inclusion of Concanavalin A resulted in a complete reversal of this trend with IGF-I, and to a lesser extent with TGF-beta 1. Cell surface levels of TIMP-2 and MT1-MMP were decreased by the TGF-beta 1 treatment while IGF-I only appeared to decrease TIMP-2 expression. The findings of this study provide some insight as to why dense avascular connective tissues such as the intervertebral disc have such a poor healing potential.

Partial purification and characterization of proteins with growth promoting activities from ovine mammary gland secretions

Developmental regulation of growth promoting activities in mammary secretions of pregnant Awassi ewes was defined, and growth factors contained in these secretions were partially purified and characterised. Mammary secretions from pregnant ewes enhanced fibroblast cell (AKR-2B) and mammary cell (CID-9 cell strain) proliferation to levels comparable to that induced by 10% Foetal calf serum. Major milk proteins in mammary secretions collected from pregnant ewes one month prior to lambing up to one week after lambing, were resolved by SDS-PAGE, while gelatinases were resolved by zymography. Gelatinase activity was noted prior to P134 and decreased thereafter to reach a minimum during lactation. This decrease was concomitant with the onset of casein production. It is during this critical developmental period that highest growth promoting activity in mammary secretions was detected. Secretions with highest growth promoting activity were fractionated by ion exchange and gel filtration chromatography. Two heat-resistant, trypsin/chymotrypsin sensitive, growth-promoting activities were characterised. The first, designated ovine mammary derived growth factor-1 (oMDGF-1), had around a 30 kDa molecular weight and eluted at 0.65 M NaCl gradient on cation ion exchange chromatography. The second, oMDGF-2, eluted under gel filtration conditions at a molecular weight of 50 kDa and 150 kDa. oMDGF-1 induced changes in Connexin 43, but not in beta-casein mRNA expression by CID-9 mammary cells. In conclusion, growth factor activities in ewe mammary secretions peak during gestation at a period that overlaps maximal gelatinase expression and precedes milk protein synthesis. The factors modulate mammary cell function and may play a role in mammary gland development.

Induction of a novel gelatinolytic activity in synovial tissue of patients with rheumatoid arthritis

Gelatinolytic activity induced by longtime incubation at 37 degrees C was found in extracts of rheumatoid synovial tissues. The enzyme activity was assessed by gelatin zymography and 3H-gelatin degradation assay. The observed enzyme had different characteristics from matrix metalloproteinases; it did not require metal ions for activity. However, metallocheltors blocked activation and addition of some metal ions restored the activation. The molecular size of the enzyme was changed time-dependently. The approximate molecular weight of the first enzyme produced by incubation was 65 kDa and it was converted to a broad size molecule with a molecular weight of 50 kDa after further incubation. Substrate specificity was detected for denatured collagen types I, II, III and IV.

In vivo perimenstrual activation of progelatinase B (proMMP-9) in the human endometrium and its dependence on stromelysin 1 (MMP-3) ex vivo

Most matrix metalloproteinases (MMPs) are secreted as inactive proenzymes. Their expression is well documented in several human tissues, but their activators in vivo are still unknown. To address this question, the activation of progelatinase B (proMMP-9) in the human endometrium was selected as a model system. ProMMP-9 was detected by gelatin zymography in homogenates of fresh endometrial tissue sampled during all phases of the menstrual cycle, whereas its active form was observed only during the late secretory and menstrual phases. Furthermore, proMMP-9 was expressed and activated in endometrial explants sampled outside the perimenstrual phase and cultured in the absence of both progesterone and oestradiol, mimicking the menstrual condition in vivo. Analysis of such tissue cultures by gelatin zymography and Western blotting showed that activation of proMMP-9 depended on a secreted factor and was selectively inhibited by either a synthetic inhibitor of stromelysin 1 (MMP-3) or a monoclonal antibody that specifically blocks MMP-3, thus providing strong evidence for the activation of proMMP-9 in vivo by MMP-3. The activation of proMMP-3 was itself inhibited by a broad-range MMP inhibitor in most cultures, but seemed to involve multiple pathways, implying both serine proteinases and metalloproteinases, which could operate in parallel or sequentially.

Clonal variation in phenotype and life span of human embryonic fibroblasts (MRC-5) transduced with the catalytic component of telomerase (hTERT)

Expression of telomerase (hTERT) in certain cell types has been shown to extend cellular life span without malignant transformation. We studied the phenotype of 26 telomerase-transduced fibroblast clones (TTFC) generated from a mass culture of hTERT retrovirally transduced MRC-5 cells. About two-thirds of the transduced clones senesced at the expected time or shortly thereafter, despite high levels of expression of telomerase and telomere length maintenance. The remaining one-third of the clones were "immortalized" (followed for over 200 cumulative population doublings). All clones maintained a nontransformed phenotype: contact inhibition, anchorage dependency, lack of tumor formation in nude mice, dose dependency to serum and growth factors, low expression of a matrix metalloproteinase associated with metastatic invasion (MMP-9) and high expression of its inhibitor TIMP-1, and no cytogenetic abnormalities by G-banding. In addition, fibroblast-specific biological parameters, such as colony size, production of collagenase, and response to MMC and gamma radiation were tightly regulated at the clonal and subclonal levels.

Gelatinase biosynthesis-activating pheromone: a peptide lactone that mediates a quorum sensing in Enterococcus faecalis

Biosynthesis of gelatinase, a virulence factor of Enterococcus faecalis, was found to be regulated in a cell density-dependent fashion in which its production is active in late log to early stationary phase. Addition of early stationary phase culture filtrate to medium shifted the onset of gelatinase production to that of mid-log phase, suggesting that E. faecalis secretes a gelatinase biosynthesis-activating pheromone (GBAP). GBAP was isolated from culture supernatant of E. faecalis OG1S-P. Structural analysis suggested GBAP to be an 11-residue cyclic peptide containing a lactone structure, in which the alpha-carboxyl group of the C-terminal amino acid is linked to a hydroxyl group of the serine of the third residue. A synthetic peptide possessing the deduced structure showed GBAP activity at nanomolar concentrations as did natural GBAP. Database searches revealed that GBAP corresponds to a C-terminal part of a 242-residue FsrB protein. Northern analysis showed that GBAP slowly induces the transcription of two operons, fsrB-fsrC encoding FsrB and a putative histidine kinase FsrC and gelE-sprE encoding gelatinase GelE and serine protease SprE. Strains with an insertion mutation in either fsrC or a putative response regulator gene fsrA failed to respond to GBAP, suggesting that the GBAP signal is transduced by a two-component regulatory system.

Enhanced production and activation of progelatinase A mediated by membrane-type 1 matrix metalloproteinase in human oral squamous cell carcinomas: implications for lymph node metastasis

We measured the production levels of seven different matrix metalloproteinases (MMP-1, 2, 3, 7, 8, 9 and 13) and two tissue inhibitors of metalloproteinases (TIMP-1 and 2) in the homogenates of human oral squamous cell carcinomas and control normal squamous epithelia by the corresponding sandwich enzyme immunoassay systems. The levels of MMP-1, 2, 3, 8, 9, 13 and TIMP-1 were significantly higher in the carcinoma samples than in the control. Among them, only the production level of MMP-2 was significantly higher in the carcinomas with cervical lymph node metastasis than in those without metastasis (P < 0.05). Gelatin zymography demonstrated that activation ratio of the zymogen of MMP-2 (proMMP-2) is significantly higher in the carcinomas with lymph node metastasis than in those without metastasis (P < 0.05) or normal control (P < 0.01). Quantitative RT-PCR for membrane-types 1, 2 and 3 MMPs (MT1, 2 and 3-MMPs), which activate proMMP-2 in vitro, demonstrated that MT1-MMP is predominantly expressed in the carcinoma tissues, and the expression level is significantly higher in the carcinomas with lymph node metastasis than in those without metastasis (P < 0.05) or the control samples (P < 0.05). Although MT2-MMP and MT3-MMP were detected in approximately 30% of the carcinoma cases, their expression levels were extremely lower compared with that of MT1-MMP. There was a direct correlation between the MT1-MMP expression level and proMMP-2 activation ratio (r = 0.62, P < 0.01). In situ hybridization and immunohistochemistry indicated that carcinoma cells and stromal cells adjacent to carcinoma cell nests express MT1-MMP transcripts and protein. MMP-2 and TIMP-2 were also immunolocalized to the carcinoma cells in the carcinoma samples. By in situ zymography, gelatinolytic activity was demonstrated in the carcinoma cell nests and abolished by the treatment with an MMP inhibitor, BB94. These results suggest that among seven different MMPs, the production of proMMP-2 and its activation mediated by MT1-MMP play an important role in the cervical lymph node metastasis of the human oral squamous cell carcinomas.

Stromal expression of fibroblast activation protein/seprase, a cell membrane serine proteinase and gelatinase, is associated with longer survival in patients with invasive ductal carcinoma of breast

Fibroblast activation protein (FAP)/seprase is a serine integral membrane proteinase with gelatinase activity, which is expressed by activated fibroblasts in the stroma of various epithelial cancers, mesenchymal tumors and breast-cancer cells, as well as during wound repair. However, the pathophysiologic significance of its expression remains poorly understood. The present study was designed to reveal the impact of stromal expression of FAP/seprase on survival in human breast cancer. Immunohistochemical expression of FAP/seprase was restricted to stromal fibroblasts adjacent to tumor-cell nests but not cancer cells, which was confirmed by double-labeling immunohistochemistry. Clinicopathologic analysis revealed that more abundant FAP/seprase expression in 112 cases of invasive ductal carcinoma is associated with longer overall and disease-free survival. Multivariate analysis with other clinicopathologic factors demonstrated that FAP/seprase expression is an independent prognostic factor. The effect on the survival rate of FAP/seprase was also apparent in cases with lymph node metastasis. FAP/seprase expression is one of the manifestations of the stromal reaction (i.e., matrix turnover); thus, invasive ductal carcinomas with fewer stromal reactions expressing FAP/seprase may be more aggressive.

Chlamydia pneumoniae proteins induce secretion of the 92-kDa gelatinase by human monocyte- derived macrophages

Chlamydia pneumoniae, an intracellular Gram-negative respiratory bacterium, and macrophages are present in inflammatory tissue sites such as atherosclerotic lesions, where abnormal degradation of the extracellular matrix takes place. To evaluate the potential of C pneumoniae for participation in matrix destruction, we studied the effect of this bacterium on the production of 3 matrix-degrading metalloproteinases, 92-kDa gelatinase, interstitial collagenase-1, and stromelysin-1, and their natural inhibitor TIMP-1 (tissue inhibitor of metalloproteinases-1) by human monocyte-derived macrophages differentiated in vitro. Spontaneous production of collagenase and stromelysin by these cells was minimal and was not influenced by C pneumoniae. In contrast, the cells secreted substantial basal quantities of 92-kDa gelatinase, the secretion of which was stimulated (on average, 2.5-fold) by C pneumoniae. C pneumoniae regulated the expression of 92-kDa gelatinase by macrophages at the pretranslational level. Macrophages secreted only small quantities of TIMP-1. The chlamydial proteins Omp2, MOMP, and HSP60 were also found to participate in the induction of 92-kDa gelatinase by C pneumoniae. Denaturation of chlamydial proteins by boiling reduced 92-kDa gelatinase secretion only partially (by 35%), suggesting that the heat-stabile lipopolysaccharide molecules also stimulate secretion of the enzyme. The results show that production of 92-kDa gelatinase by human macrophages is selectively upregulated by C pneumoniae, which suggests that these bacteria, when present in a macrophage-containing inflammatory environment, actively participate in the destruction of the extracellular matrix.

Membrane-type 1 matrix metalloproteinase-mediated progelatinase A activation in non-tumorigenic and tumorigenic human keratinocytes

Elevated expression of type IV collagenases (MMP-2 and MMP-9) has been strongly correlated with tumour progression and metastasis in various tumours. Here, we analysed expression and activation of these MMPs in non-tumourigenic HaCaT cells and the malignant HaCaT variant II-4(rt). In monolayer cultures, both cell types secreted latent MMP-2 (proMMP-2) in comparable amounts, while MMP-9 production was clearly higher in II-4(rt)cells. Upon contact with fibrillar collagen type I the malignant II-4(rt)cells, but not the HaCaT cells, gained the capability to activate proMMP-2. This process is shown to be membrane-associated and mediated by MT1-MMP. Surprisingly, all membrane preparations from either HaCaT cells or II-4(rt)cells grown as monolayers, as well as within collagen gels, contained considerable amounts of active MT1-MMP. However, within collagen gels HaCaT cells showed significantly higher TIMP-2 levels compared to II-4(rt)cells. This indicates that TIMP-2 might play a central role for MT1-MMP-mediated gelatinolytic activity. Indeed, collagen type I-induced MT1-MMP-mediated proMMP-2 activation by II-4(rt)membranes could be completely abolished by an excess of TIMP-2. In conclusion, our data suggest that MT1-MMP-mediated proMMP-2 activation might be associated with malignant progression of epidermal tumour cells.

Mesenchymal stem cells from osteoporotic patients produce a type I collagen-deficient extracellular matrix favoring adipogenic differentiation

Mesenchymal stem cells (MSCs), precursor cells resident in the bone marrow, have the capacity to differentiate into bone, cartilage, fat, and connective tissue. We have recently reported that MSCs from "healthy" donors differ from cells obtained from osteoporotic postmenopausal women in their proliferation rate, mitogenic response to osteogenic growth factors, and potential to mineralize. The purpose of this study was to examine the factors that explain the differential capacity of MSCs derived from "healthy" control and osteoporotic postmenopausal women to support mineralization. In addition, we examined the factors that regulate the differentiation of osteoporotic cells into adipocytes. For this purpose, we isolated MSCs from bone marrow of donors and analyzed the synthesis and deposition of type I collagen, the main component of bone extracellular matrix, the time course of gelatinolytic activity expression, the deposition of transforming growth factor beta (TGF-beta), and the ability of cells to differentiate into adipocytes. Our results indicate that cells derived from osteoporotic donors synthesized 50% less type I collagen than normal cells and maintained higher levels of gelatinolytic activity under differentiation conditions (70% versus 15% after 14 days in culture). MSCs derived from osteoporotic women produced 60-65% less TGF-beta and expressed higher adipogenic capacity. We conclude that the capacity of MSCs derived from osteoporotic postmenopausal women to generate and maintain type I collagen-rich extracellular matrix is decreased, favoring their adipogenic differentiation. These observations may explain the decreased mineralization previously observed in these types of cells.

Differential regulation of MMP-2 and MMP-9 gelatinases in cultured human keratinocytes

BACKGROUND

Among matrix metalloproteinases (MMPs), MMP-2 and MMP-9 are considered to play important roles in the tissue metabolism.

OBJECTIVE

To study the production of MMP-2 and MMP-9 in cultured keratinocytes.

METHODS

We examined the effect of cell passage number and cell differentiation on these enzymes by zymography and immunocytochemistry.

RESULTS

Both MMP-2 and MMP-9 gelatinases were detected in keratinocyte-conditioned media using zymography. The level of MMP-2 in the medium decreased after sequential passage, whereas MMP-9 was detected at a constant level. Treatment of keratinocytes with Ca2+, a potent stimulator for cell differentiation. induced secretion of MMP-9, which was confirmed immunocytochemically. Inversely, treatment with retinoic acid, which inhibits cell differentiation, increased the level of MMP-2.

CONCLUSION

These results suggest that keratinocytes regulate their secretion of MMP-2 and MMP-9 gelatinase in distinct and independent patterns during differentiation.

Expression of proteinases and proteinase inhibitors during embryo-uterine contact in the pig

Implantation in pigs is noninvasive and characterized by interdigitation of embryonic and endometrial epithelial cell processes. However, when pig embryos are transferred to ectopic sites, trophoblast becomes invasive. The objective of this study was to evaluate expression of proteinases and proteinase inhibitors in pig embryos and uteri at the time of endometrial attachment. RNA was extracted from Day 15.75 pig embryos and uteri and reverse transcribed, and cDNA was amplified by polymerase chain reactions using primers specific for urokinase-type plasminogen activator (uPA), matrix metalloproteinases-2 and -9 (MMP-2 and -9), and tissue inhibitors of MMP-1, -2, and -3 (TIMP-1, -2, and -3). Localization of transcripts for the genes of interest in embryos and uteri was performed using in situ hybridization with antisense riboprobes. Day 15.75 pig embryos and uteri expressed transcripts for uPA, MMP-2 and -9, and TIMP-1, -2, and -3. In situ hybridization revealed weak expression of uPA in the trophectoderm and moderate expression in the adjacent extraembryonic endoderm. TIMP-1 transcripts were abundant in extraembryonic endoderm and scattered throughout the trophectoderm. TIMP-2 appeared to be expressed in all cells of the embryo. TIMP-3 expression was observed in the trophectoderm and, to a lesser extent, in the extraembryonic endoderm. Specific localization of MMP-2 and -9 transcripts above background was not observed by in situ hybridization in either embryos or uterus. Uterine expression of uPA and TIMP-1, -2 and -3 was localized to the endometrial stroma. Transcripts of these genes were not observed in either the luminal or glandular endometrial epithelium. These results suggest that pig embryos and uteri express a wide array of proteinases and proteinase inhibitors during the period of uterine association. The abundant expression of proteinases and proteinase inhibitors during the period of uterine association. The abundant expression of TIMP in pig embryos may partially explain the absence of invasive implantation in this species in contrast to implantation typified by rodents and primates.

Effects of Enterococcus faecalis fsr genes on production of gelatinase and a serine protease and virulence

Three agr-like genes (fsrA, fsrB, and fsrC, for Enterococcus faecalis regulator) were found upstream of the previously reported gelatinase gene (gelE) and a downstream putative serine protease gene (sprE; accession number Z12296) of Enterococcus faecalis OG1RF. The deduced amino acid sequence of fsrA shows 26% identity and 38% similarity to Staphylococcus aureus AgrA (the response regulator of the accessory gene regulator system in the agr locus), FsrB shows 23% identity and 41% similarity to S. aureus AgrB, and FsrC shows 23% identity and 36% similarity to S. aureus AgrC (the sensor transducer of Agr system). Northern blot analysis suggested that gelE and sprE are cotranscribed and that fsrB and fsrC are also cotranscribed in OG1RF. Northern blot analysis of fsrA, fsrB, fsrC, gelE, and sprE insertion mutants showed that fsrB, fsrC, gelE, and sprE are not expressed in fsrA, fsrB, and fsrC mutants, while insertion in an open reading frame further upstream of fsrA did not effect the expression of these genes, suggesting that agr-like genes may be autoregulated and that they regulate gelE and sprE expression, as further confirmed by complementation of fsr gene mutations with a 6-kb fragment which contains all three fsr genes in the shuttle vector, pAT18. Testing of 95 other isolates of E. faecalis showed that 62% produced gelatinase (Gel(+)), while 91% (including all Gel(+) strains) hybridized to a gelE probe; 71% (including all Gel(+) strains) hybridized to an fsr probe, corroborating the conclusion that both gelE and fsr are necessary for gelatinase production. Testing of fsrA, fsrB, and sprE mutants in a mouse peritonitis model showed that sprE and agr-like gene mutants resulted in highly significantly prolonged survival compared to the parent strain OG1RF, a finding similar to what we had previously shown for a gelE mutant. These results suggest that sprE and agr-like genes contribute to the virulence of E. faecalis OG1RF in this model.

Membrane-type matrix metalloproteinase expression and matrix metalloproteinase-2 activation in primary human ovarian epithelial carcinoma cells

Metastatic dissemination of epithelial ovarian carcinoma occurs primarily through exfoliation of cells from the primary tumor, with subsequent implantation, invasion, and growth throughout the organs within the peritoneal cavity. Previous studies have suggested a role for matrix metalloproteinases (MMPs), particularly MMP-2, in ovarian cancer invasion and metastasis. To characterize further the role of MMPs and their inhibitors in ovarian carcinoma, in this study the production and activation of MMPs by short-term primary cultures of human ovarian epithelial carcinoma cells were analyzed. We report that MMP-2 is the predominant gelatinolytic MMP secreted by primary ovarian cancer cells derived from both ovarian tumors and ascites fluid. Furthermore, zymographic analysis demonstrated that MMP-2 is present in conditioned media in both the latent and activated forms, indicating that primary ovarian cancer cells catalyze proMMP-2 activation. Presence of a proMMP-2 activator was confirmed by immunohistochemistry and immunoprecipitation studies which found membrane-type 1 MMP (MT1-MMP) in the membranes of unstimulated cells and levels of both MT1-MMP and tissue inhibitor of metalloproteinases-2 (TIMP-2) were enhanced by culturing cells in the presence of concanavalin A. In addition, interaction of MMP-2 with the ovarian carcinoma cell surface resulted in a 2.5- to 5-fold increase in invasiveness. These data suggest that MT1-MMP-catalyzed activation of proMMP-2 may play a physiologic role in intraperitoneal invasion of ovarian carcinoma cells.

The role of protein-tyrosine phosphorylation and gelatinase production in the migration and proliferation of smooth muscle cells

BACKGROUND

It has been reported that matrix metalloproteinase (MMP) was expressed in coronary arterial atherosclerotic lesions. However, not much is known about the relationship between the production of MMP and the progression of atherosclerosis.

PURPOSE AND METHOD

To demonstrate the association between the protein-tyrosine phosphorylation (PTP) and the activation of extracellular MMP in the proliferation and migration of vascular smooth muscle cells (VSMCs), the effect of platelet-derived growth factor (PDGF) and vanadate (an inhibitor of protein-tyrosine phosphatase and an activator of certain protein-tyrosine kinases) on mitogenesis ([3H]thymidine incorporation after 24 hours), migration, PTP (Western blot analysis using anti-phosphotyrosine antibodies), and production of MMP (gelatin zymography) was examined in cultured VSMCs.

RESULTS

Both vanadate (1-5 micromol/l) and PDGF (1-10 ng/ml) caused a dose-dependent increase in thymidine incorporation and migration and produced 72-kDa type IV gelatinase (MMP-2) in VSMCs. The combination of vanadate and PDGF resulted in a dose-dependent synergistic effect on thymidine incorporation and MMP-2 production. Western blot analysis revealed that PDGF caused an increase in PTP, extracellular signal-regulated kinases (ERK1, ERK2) and PDGF receptor in VSMCs. Vanadate given together with PDGF induced a marked increase in the intensity of tyrosine phosphorylation in these proteins. Tyrosine kinase inhibitors (genistein and herbimycin A) and a synthetic inhibitor of MMP (1,10-phenanthroline) and an anti-MMP-2 neutralizing antibody inhibited the mitogenic effect induced by vanadate and/or PDGF.

CONCLUSIONS

The data suggest that the proliferation and migration of cultured VSMCs was closely related to the stimulation of MMP-2 production that was induced through activation of PTK.

Induction of the putative protective protein ferritin by infrared radiation: implications in skin repair

The modification of ferritin in human skin cells in vitro and in vivo following infrared-A irradiation by immunohistochemical analysis and ELISA were evaluated. In addition, we observed that IR-A is not capable of inducing frank damage to DNA (pyrimidine dimers, p53), induction of oxidative stress proteins (heme oxygenase, nitric oxide, superoxide dismutase, heat shock proteins) or proteases (collagenase, stromelysin, gelatinase) involved in carcinogenesis and photoaging of the skin. in vivo, basal levels of ferritin were heterogeneous for all individuals tested but all showed ferritin to stain precisely in the basal layer of unirradiated epidermis. Following IR-A radiation, the ferritin increase was localized to epidermal tissue and showed an increase from 120 to 220%. Parallel to the in vivo analysis, dermal fibroblasts were cultured from six individuals. Quantitative analysis for ferritin in cultured fibroblasts was assessed by ELISA and increases were seen to be dose-dependent and up to 130% of basal levels of ferritin following infrared-A. Our findings indicate that the putative defense system of ferritin that exists in human skin in vivo can be induced by infrared-A radiation and that these wavelengths may prove to be beneficial for human skin. Importantly, following the same doses of IR-A that induced ferritin levels, there was no alteration seen for nuclear DNA type damage, oxidative stress proteins or proteases involved in the degradation of skin. The increased concentrations of this antioxidant in human skin following acute UV radiation could afford increased protection against subsequent oxidative stress.

The individual regulation of granule protein mRNA levels during neutrophil maturation explains the heterogeneity of neutrophil granules

The in vivo mRNA levels for 16 granule proteins during neutrophil differentiation were determined to address the question of whether the synthesis of granule proteins is regulated individually or blockwise. RNA was extracted from peripheral blood granulocytes and three different populations of neutrophil precursors isolated from human bone marrow by Percoll density centrifugation. The mRNA levels in relation to the maturation of the cells were determined by Northern blot for the 12 matrix proteins myeloperoxidase, proteinase-3, elastase, defensin, lactoferrin, NGAL, hCAP-18, transcobalamin-I, SGP28, gelatinase, lysozyme, and serglycin and the 4 membrane proteins CD68, CD11b, N-formyl-methionyl-leucyl-phenylalanine receptor, and CD35. This panel of transcripts ensured that markers for all exocytosable organelles of the neutrophil were included in the study. A highly differentiated distribution of mRNAs for granule proteins was demonstrated that can explain the heterogeneity of the intracellular storage granules and secretory vesicles of the neutrophil. Furthermore, the individual distribution of these transcripts provides the basis for a more detailed assessment of neutrophil maturation than that obtained by morphological studies or the use of a single marker protein for azurophil, specific, and gelatinase granules.

Collagenase and gelatinase messenger ribonucleic acid expression and activity during follicular development in the rat ovary

Metalloproteinases are members of a family of proteinases that remodel the extracellular matrix throughout the body. To test the hypothesis that metalloproteinases are regulated by gonadotropin-induced changes during follicular growth, rats were injected with eCG (20 IU, s.c.), and ovaries and serum were collected at the time of eCG administration (0 h) and at 6, 12, 24, 36, or 48 h later for analysis of metalloproteinase mRNA expression, metalloproteinase activity, and steroidogenesis. Serum estradiol levels increased from 18.9 pg/ml at 0 h to 503.8 pg/ml at 48 h. Analysis of mRNA expression was performed for collagenase-3, 72-kDa gelatinase, and 92-kDa gelatinase (n = 3-4). For collagenase-3, eCG stimulated a 32-fold increase in collagenase-3 mRNA at 48 h after eCG injection as compared to that in ovaries collected at the time of eCG administration (i.e., 0-h control). The mRNA levels for 72-kDa gelatinase were 2.8-fold compared to 0 h at 36 h after eCG treatment and returned to control levels by 48 h after gonadotropin treatment. Levels of the 92-kDa mRNA expression peaked at 24 h (4. 2-fold compared to 0 h) and returned to control levels by 36 h. Gel zymography revealed 3 gelatinolytic bands corresponding to the gelatinases of approximately 72 kDa, 92 kDa, and 105 kDa. Analysis of metalloproteinase activity as the degradation of collagen or gelatin per ovary showed an increase in gelatinolytic and collagenolytic activity between 12 and 48 h after eCG treatment. In summary, these findings demonstrate that the gonadotropin induction of folliculogenesis results in changes in the metalloproteinases that may be responsible for extracellular matrix remodeling associated with follicular growth.

Over-expression of cyclin D1 induces glioma invasion by increasing matrix metalloproteinase activity and cell motility

In order to define the role of cyclin D1 in the progression of malignant glioma, cells over-expressing cyclin D1 were constructed (a-1 cells). They exhibited significantly increased invasiveness as compared with mock-transfected cells. Since cellular invasion is thought to depend on extracellular-matrix degradation, we determined whether cyclin-D1 expression modifies the activity of matrix metalloproteinases (MMPs). Increased gelatinolytic activity of latent type MMP-2 (proMMP-2) and active MMP-2 was observed in a-1 cells. Moreover, cyclin-D1 expression was associated with increased activation of proMMP-9 through MMP-3. Wound assays showed an increase of cell motility in a-1 cells. Cyclin-D1 expression was found to be associated with up-regulation of Rac1, which modulates the formation of ruffling membranes and cell motility. Our results show that cyclin D1 may modulate invasive ability by increasing MMP activity and cell motility, and suggests a novel function of cyclin D1 in the progression of malignant gliomas.

Progelatinase A is produced and activated by rat hepatic stellate cells and promotes their proliferation

Activated hepatic stellate cells (HSCs) are a potential source of gelatinase A, which accumulates in fibrotic livers. Progelatinase A activation requires its binding to a complex of membrane-type matrix metalloproteinase (MT-MMP) and tissue inhibitor of metalloproteinases (TIMP)-2. These studies examine gelatinase A, MT1-MMP, and TIMP-2 synthesis by HSCs during activation in vitro and the potential role of gelatinase A in promoting HSC proliferation. Gelatinase A, MT1-MMP, and TIMP-2 messenger RNA (mRNA) were all upregulated in HSCs activated on plastic over 5 to 14 days. Gelatinase A expression was maximal at 7 days of culture, coinciding with the peak of HSC proliferation and the onset of procollagen I and alpha-smooth muscle actin (alpha-SMA) mRNA expression. Active forms of gelatinase A of 62 kd and 66 kd were secreted by activated HSCs and reached a maximum of 12.1% of total enzyme in 14-day culture supernatants. Treatment of HSCs with concanavalin A (con A) induced activation of MT1-MMP and enhanced secretion of activated gelatinase A, which reached a maximum of 44.4% of the total enzyme secreted into culture supernatants using 30 microgram/mL con A. [(14)C]-gelatin degradation assays confirmed the presence of gelatinolytic activity in activated HSC supernatants, which reached a maximum level at 7 days of culture. Antisense oligonucleotide inhibition of endogenous progelatinase A production, or the MMP inhibitor 1,10-phenanthroline inhibited (3)H-thymidine incorporation into HSC DNA by greater than 50%. We conclude that HSCs produce progelatinase A during activation in vitro and activate this enzyme coincident with MT1-MMP and TIMP-2 synthesis. Gelatinase A activity is required for maximal proliferation of HSCs in vitro suggesting this metalloproteinase is an autocrine proliferation factor for HSCs.

Long-term alcohol consumption increases matrix metalloproteinase-2 activity in rat aorta

Altered degradation of extracellular matrix (ECM) underlies vascular remodeling, a hallmark in the pathogenesis of cardiovascular diseases including hypertension and aneurysmal dilatation. Although alcohol is recognized as a risk factor for certain cardiovascular disease states, its role in vascular remodeling has not been completely explored. We studied the effect of chronic alcohol consumption on upregulation of the enzymatic activity of matrix metalloproteinase-2 (MMP-2) as a possible pathway for large vessel remodeling. For this purpose, female rats were placed on one of three diets: a modified Lieber-DeCarli liquid diet containing 35% ethanol-derived calories, a pair-fed liquid diet with ethanol replaced by isocaloric maltose-dextrin, or a standard rat pellet. Weekly blood alcohol concentration averaged 117+/-7.9 mg/dl for the alcohol-fed rats. At 2, 4, and 72 weeks, aortas were removed and processed for measuring MMPs activity by gelatin zymography. Aortic extracts from rats on long-term (72 weeks), but not the short-term (2 and 4 weeks), alcohol diets showed increased MMP-2 activity. Furthermore, histochemical analysis of the aortas showed distinct disruption of the elastic fibers only in the 72 weeks alcohol-fed rats, compared to the control animals. These observations demonstrate that long-term alcohol consumption up-regulates MMP-2 activity, which is coincident with the alteration of aortic ECM composition through the degradation of vascular elastin components.