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[Gene expression of matrix metalloproteinase 14 in laryngeal squamous cell carcinoma].

OBJECTIVE: To investigate the role of expression of matrix metallo-proteinase 14 (MMP14) in laryngeal carcinomas and the relationship between MMP14 expression and the laryngeal biological behavior. METHODS: The gene expression differences of MMP14 between fresh laryngeal cancer tissues and their surrounding normal mucosa was analyzed by RT-PCR. The expression of MMP14 protein in paraffin-embedded tissues was determined immunohistochemically. All statistical analyses were performed by SPSS version 10.0. RESULTS: In the 33 cases of matched specimens, MMP14 gene expression was much higher in tumor tissues than that in surrounding ing normal tissues in 26 cases and lower in 2 cases, whereas in other 5 cases, no significant difference was observed between the cancer tissue and the surrounding normal tissue. MMP14 gene expression was not different in different stages in laryngeal glottic cancers, but correlated to the differentiation and lymph node metastasis (P < 0.05). There was correlation between MMP14 gene expression and the stage, differentiation and lymph node metastasis in the laryngeal supraglottic cancers (P < .05). MMP14 protein was localized predominantly in the carcinoma cell cytoplasm and in the stromal fibroblast cytoplasm, and weakly or not expressed in surrounding normal tissue. MMP14 protein expression was much higher in tumor tissue than that in surrounding normal tissue in most of the cases. In general, MMP14 protein expression was the same as MMP14 gene expression and related to the stage, differentiation and lymph node metastasis in the laryngeal cancers. There was no survival difference at 3, 5 and 7-year between the group with higher MMP14 protein expression in tumor tissues than surrounding normal tissues and the group with no difference of MMP14 protein expression (Log Rank, P=0.5535). CONCLUSIONS: The protein MMP14 may play role in laryngeal cancer invasion in a certain extent, but important role in lymph node metastasis of laryngeal cancer. The over-expression of MMP14 protein may be a marker for lymph node metastasis of laryngeal cancer.

Carcinoma, Squamous Cell↗

The matrix metalloproteinase-14 (MMP-14) gene is structurally distinct from other MMP genes and is co-expressed with the TIMP-2 gene during mouse embryogenesis.

The matrix metalloproteinases (MMPs) are a family of zinc-containing matrix degrading endopeptidases. A subfamily of membrane type (MT) -MMPs has been described recently. We have determined the structure of the gene (Mmp14) encoding the first MT-MMP to be described, MT1-MMP (MMP-14), and mapped it to mouse chromosome 14. The mouse MMP-14 protein is encoded by ten exons. The novel C-terminal peptide domains of MMP-14 are encoded by a single large exon that also encodes the 3'-untranslated region. The structure of the exons encoding the catalytic domain and pro-domain of MMP-14 is distinct from previously described MMP genes, whereas the exons encoding the hemopexin-like domains are similar to those of most other MMP genes. Mmp14 and the gene for tissue inhibitor of metalloproteinases-2 (Timp2) show a temporally and spatially co-regulated expression during mouse development. They are co-expressed during vascular and urogenital development and during the development of osteocartilaginous and musculotendinous structures. The stringent co-expression of these two genes suggests common regulatory pathways that may have important functional implications for the activation of pro-gelatinase A in health and disease.

Animals↗

Clinicopathologic and prognostic significance of matrix metalloproteinases in rectal cancer.

BACKGROUND AND AIMS: The aim of this study was to determine the prognostic role of matrix metalloproteinases in rectal cancer. MATERIALS AND METHODS: Formalin-fixed and paraffin-embedded tissue sections of 94 rectal carcinomas were used for the immunohistochemical analysis of matrix metalloproteinases (MMP)-2, MMP-7, MT1-MMP, and tissue inhibitor of metalloproteinases (TIMP)-2. Inclusion criteria were sporadic rectal adenocarcinoma resected curatively (including total mesorectal excision), adjuvant radiochemotherapy in UICC stages II and III, and complete intra-institutional follow-up. Results of immunohistochemistry were correlated with clinical and histopathologic data from the prospective rectal cancer registry and prognosis. End points of the prognostic analysis were tumor progression caused by local and/or distant recurrence and 5-year survival (disease-free and overall). To assess prognostic significance, statistics included univariate and multivariate analysis (p<0.05 statistically significant). RESULTS: Of the 94 rectal carcinomas, 35% (33/94) showed an epithelial MMP-2 expression, 77% (72/94) were MMP-2 positive in the stroma. Fifty-four percent (51/94) were MMP-7 positive, and 47% (46/94) were positive for both MT1-MMP and TIMP-2. The stromal MMP-2 staining pattern was correlated with the depth of invasion (pT status, p=0.006) with MMP-7 (p=0.016) and TIMP-2 expression (p=0.036). Positive expression of MMP-2 in tumor epithelium was correlated with MMP-7 (p=0.027), MT1-MMP (p=0.036), and TIMP-2 expression (p<0.0001). A positive staining pattern of MMP-7 was significantly correlated with depth of invasion and TIMP-2 (p<0.01). The positive staining pattern of MT1-MMP was correlated with epithelial MMP-2 (p=0.036), MMP-7 (p=0.004), and TIMP-2 expression (p=0.002). TIMP-2 immunoreactivity correlated with depth of invasion (p=0.013), epithelial MMP-2 (p<0.001), stromal MMP-2 (p=0.036), MMP-7 (p<0.001), and MT1-MMP (p=0.002). Neither pattern correlated with age, gender, tumor stage (UICC), grading, preoperative serum carcinoembryonic antigen (CEA) level, or nodal status (p>0.05). Within a mean follow-up of 46 months, tumor progression, caused by either local recurrence or distant metastasis, occurred in 14 patients (15.4%). There was no significant association between the MMP expression and the incidence of local and/or distant recurrence. In terms of survival, preoperative CEA level (disease-free 5-year survival 46% with increased CEA vs 70% with normal CEA, p=0.01; overall 5-year survival 43 vs 74%, p<0.01) and UICC stage were the only factors to be significantly related to 5-year survival by univariate analysis, whereas the metalloproteinases failed to show a significant association. In multivariate analysis, CEA and UICC stage were not identified as independent factors predictive of survival. CONCLUSION: MMP-2, MMP-7, MT1-MMP, and TIMP-2 do not appear to be significant predictors of prognosis in a homogenous collective of curatively resected rectal adenocarcinomas.

Adenocarcinoma↗

Presence of high levels of MT1-MMP protein in fibroblastic cells of human invasive carcinomas.

Matrix metalloproteinase 2 (MMP2) activity is associated with the aggressiveness of human cancers. Therefore, the mechanisms regulating its activation are of great interest for a better understanding of malignant invasive processes. MT1-MMP, a membrane-bound MMP, is involved in the conversion of the latent form of MMP2 to the active one. In the present study, we have raised 3 monoclonal antibodies (Mabs) directed against 3 different epitopes of human MT1-MMP, which we used to investigate the expression and cellular localization of MT1-MMP protein in human carcinomas. MT1-MMP protein was present in all invasive carcinomas tested, and it was almost exclusively located to the stromal cells and not to cancer cells as previously reported, suggesting that MMP2 activation might be a peri-fibroblastic event.

Animals↗

Expression and activation of matrix metalloproteinase-2 (MMP-2) and its co-localization with membrane-type 1 matrix metalloproteinase (MT1-MMP) correlate with melanoma progression.

Matrix metalloproteinases (MMPs) and their specific tissue inhibitors (TIMPs) play an important role in cancer cell invasion and metastasis. Recently, it was shown that the presence of activated MMP-2 correlates with melanoma progression in vitro. This activation involves coordinated expression of MMP-2, membrane-type 1 MMP (MT1-MMP), and TIMP-2. To investigate the expression profile of these enzymes in human melanoma, this study used tumour specimens obtained from both a human melanoma xenograft model, consisting of eight melanoma cell lines with different metastatic capacity in nude mice, and 60 fresh human cutaneous melanocytic lesions comprising all stages of melanocytic tumour progression. MT1-MMP and TIMP-2 mRNA and protein were present in all cell lines. Cell surface expression level of MT1-MMP, as determined by flow cytometry, was similar on all cell lines. In addition, western blot analysis revealed that both inactive and active MT1-MMP protein was expressed by all cell lines. MMP-2 mRNA and the pro-enzyme form of MMP-2 were expressed by all cell lines. Remarkably, the presence of functionally active MMP-2 was restricted to the most aggressive cell lines MV3 and BLM. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of RNA isolated from subcutaneous xenografts revealed MT1-MMP and TIMP-2 mRNA expression in all lesions, whereas MMP-2 mRNA could be detected only in xenografts derived from the highly metastatic cell lines 1F6m, MV3, and BLM. Furthermore, immunohistochemistry demonstrated a marked increase of MMP-2 and MT1-MMP in MV3 and BLM xenografts, whereas TIMP-2 expression showed no evident correlation with metastatic capacity. In human cutaneous melanocytic lesions, MMP-2, MT1-MMP, and TIMP-2 mRNA were detectable by RT-PCR in all lesions. Expression of MMP-2 protein was not detectable, either in common and atypical naevi, or in melanoma in situ by immunohistochemistry. In these lesions, heterogeneous expression of MT1-MMP and TIMP-2 was present in melanocytic cells. In contrast, a large number of MMP-2 and MT1-MMP-positive tumour cells were observed in primary melanomas and melanoma metastases. Double staining experiments and immunohistochemistry on serial sections from the same lesions demonstrated that all tumour cells expressing MMP-2 also expressed MT1-MMP and TIMP-2. Finally, zymography of melanoma metastases revealed that MMP-2 was present in its functionally active form. This study demonstrates that expression of MT1-MMP and TIMP-2 and activation of MMP-2 are correlated with tumour progression both in the xenograft model and in human melanocytic lesions, strongly suggesting that these factors are required for melanoma invasion and metastasis formation.

Animals↗

Expression of integrin alpha(v)beta(3) correlates with activation of membrane-type matrix metalloproteinase-1 (MT1-MMP) and matrix metalloproteinase-2 (MMP-2) in human melanoma cells in vitro and in vivo.

Activation of matrix metalloproteinase-2 (MMP-2) is mediated by binding to the complex of membrane-type matrix metalloproteinase-1 (MT1-MMP) with tissue inhibitor of MMP-2 (TIMP-2) on the cell surface. Binding of MMP-2 to integrin alpha(v)beta(3) has been implicated in presenting activated MMP-2 on the cell surface of invasive cells, but interactions with the MT1-MMP-TIMP-2 system have not been considered. Therefore, we studied the expression and interaction of MT1-MMP, MMP-2 and TIMP-2 in the alpha(v)beta(3)-negative melanoma cell line BLM and in its beta(3)-transfected, alpha(v)beta(3)-expressing counterpart BLM-beta(3), both on cell lines and in xenografts. Total expression levels of MMP-2, MT1-MMP and TIMP-2 did not differ markedly between the alpha(v)beta(3)-negative and alpha(v)beta(3)-positive cells. Remarkable differences, however, exist in the presence of active MMP-2 and MT1-MMP. Zymography on cell lysates revealed that active MMP-2 was restricted to alpha(v)beta(3)-positive cell line and clearly accumulated in xenografts derived from the BLM-beta(3) cells, confirming the relevance of this integrin for MMP-2 function. Western blotting of cell lysates showed that processing of proMT1-MMP to the activated form was enhanced in BLM-beta(3). The ratio of active and inactive MT1-MMP was 3-fold higher in the beta(3)-transfectants. Immunofluorescence double-labeling followed by confocal laser microscopy showed co-localization of MT1-MMP and alpha(v)beta(3) on BLM-beta(3) cells. In xenografts from BLM-beta(3) cells, active MT1-MMP was markedly increased. Our results demonstrate that expression of alpha(v)beta(3) in cell lines and xenografts was accompanied by an accumulation of active MT1-MMP and MMP-2. Furthermore, MT1-MMP and alpha(v)beta(3) are co-localized on the cell membrane of tumor cells. These findings suggest that activated MT1-MMP co-localized with alpha(v)beta(3) may be involved in activation of alpha(v)beta(3)-bound MMP-2.

Animals↗

Retroviral gene transfer of an antisense construct against membrane type 1 matrix metalloproteinase reduces the invasiveness of rheumatoid arthritis synovial fibroblasts.

OBJECTIVE: Membrane type 1 matrix metalloproteinase (MT1-MMP) is expressed prominently in rheumatoid arthritis synovial fibroblasts (RASFs), but the specific contribution of MT1-MMP to fibroblast-mediated destruction of articular cartilage is incompletely understood. This study used gene transfer of an antisense expression construct to assess the effects of MT1-MMP inhibition on the invasiveness of RASFs. METHODS: Retroviral gene transfer of a pLXIN vector-based antisense RNA expression construct (MT1-MMPalphaS) to MT1-MMP was used to stably transduce RASFs. Levels of MT1-MMP RNA and protein were determined by quantitative polymerase chain reaction, Western blotting, and immunocytochemistry in MT1-MMPalphaS-transduced RASFs as well as in control cells, with monitoring for 60 days. The effects of MT1-MMPalphaS on the invasiveness of RASFs were analyzed in the SCID mouse co-implantation model of RA. RESULTS: MT1-MMPalphaS-transduced RASFs produced high levels of antisense RNA that exceeded endogenous levels of MT1-MMP messenger RNA by 15-fold and resulted in a down-regulation of MT1-MMP at the protein level. Inhibition of MT1-MMP production was maintained for 60 days and significantly reduced the invasiveness of RASFs in the SCID mouse model. Whereas prominent invasion into cartilage by non-transduced and mock-transduced RASFs was observed (mean invasion scores 3.0 and 3.1, respectively), MT1-MMPalphaS-transduced cells showed only moderate invasiveness (mean invasion score 1.8; P < 0.05). CONCLUSION: The data demonstrate that an antisense RNA expression construct against MT1-MMP can be generated and expressed in RASFs for at least 60 days. Inhibition of MT1-MMP significantly reduces the cartilage degradation by RASFs.

Animals↗

Platelet-derived growth factor C plays a role in the branchial arch malformations induced by retinoic acid.

BACKGROUND: All-trans-retinoic acid (RA) can produce branchial arch abnormalities in postimplantation rodent embryos cultured in vitro. Platelet-derived growth factor C (PDGF-C) was recently identified as a member of the PDGF ligand family. Many members of the PDGF family are essential for branchial arch morphogenesis and can be regulated by RA. The roles of PDGF-C in branchial arch malformations induced by RA and possible mechanisms were investigated. METHODS: In whole embryo culture (WEC), mouse embryos were exposed to RA at 0, 0.1, 0.4, 1.0, or 10.0 microM, PDGF-C at 25, 50, or 75 ng/mL, or PDGF-C at 25, 50, or 75 ng/mL containing 0.4 microM RA. After 48 h of culture, mouse embryos were examined for dysmorphogenesis, and whole-mount immunohistochemistry was applied to PDGF-C. In explant cultures, explants were exposed to the same doses of RA and PDGF-C as WEC. Semiquantitative RT-PCR, zymography, and reverse zymography were used to evaluate the expressions and activities of matrix metalloproteinase (MMP)-2, MMP-14, and tissue inhibitor of metalloproteinase (TIMP)-2. RESULTS: PDGF-C was reduced by RA, and exogenous PDGF-C rescued the branchial arch malformations induced by RA. Moreover, PDGF-C prevented RA-induced inhibition of the migratory ability of mesenchymal cells in the first branchial arch, by regulating the expressions of MMP-2, MMP-14, and TIPM-2. CONCLUSIONS: Our results suggest that RA exposure reduces the expression of PDGF-C. The branchial arch malformations resulting from fetal RA exposure are caused at least partially by loss of PDGF-C and subsequent misregulations of the expressions of MMP-2, MMP-14, and TIMP-2.

Animals↗

EphA2 overexpression is associated with angiogenesis in ovarian cancer.

BACKGROUND: EphA2 is overexpressed in the majority of ovarian cancers and predicts poor clinical outcome. Based on EphA2's emerging role in angiogenesis, we hypothesized that tumors overexpressing EphA2 demonstrate greater microvessel density (MVD) and matrix metalloproteinase (MMP) expression. METHODS: After Institutional Review Board (IRB) approval, 77 invasive epithelial ovarian tumors were analyzed for CD31, EphA2, MMP-2, MMP-9, and MT1-MMP expression. RESULTS: The median age of the patients was 59 years (range, 34-83). EphA2 was overexpressed in 76% of tumors and was associated with advanced-stage disease (P < .001) and high-grade histology (P = .04). MVD was stratified into high (>12.7 vessels/high-power field [HPF]) versus low (<or=12.7 vessels/HPF) counts. High MVD was significantly associated with advanced stage (P < .001), presence of ascites (P < .001), and suboptimal surgical cytoreduction (P = .01). MMP expression was scored separately in the stromal (percentage of tumors with high expression: MMP-2 = 43%; MMP-9 = 74%; MT1-MMP = 40%) and epithelial (percentage of tumors with high expression: MMP-2 = 52%; MMP-9 = 61%; MT1-MMP = 44%) compartments. Endothelial cell EphA2 overexpression correlated with epithelial MMP-9 (P = .02), whereas EphA2 overexpression in tumor cells was significantly associated with high MVD (P = .002), as well as strong stromal and epithelial MMP-9 (P = .01 and P = .04, respectively), epithelial MMP-2 (P = .006), and epithelial MT1-MMP (P = .01) expression. CONCLUSIONS: EphA2 overexpression in endothelial and ovarian cancer cells was strongly associated with critical factors involved in angiogenesis and invasion. These findings may explain the poor clinical outcome of patients with EphA2 overexpression.

Adult↗

Membrane-type 1 matrix metalloproteinase is required for normal alveolar development.

Matrix metalloproteinases (MMPs) are expressed during lung development, but their role may be limited, as mice deficient in MMP-3, 7, 9, or 12 develop a normal adult lung. Because membrane-type 1 matrix metalloproteinase (MT1-MMP) is expressed in the developing lung epithelium, we examined the lung structure of MT1-MMP-deficient (-/-) mice. Branching morphogenesis was normal, but alveolar development was abnormal in the MT1-MMP-/- lungs with 40% less alveolar surface area at 1 month (P < 0.01). MT1-MMP-/- airways and alveoli had an abnormal ultrastructural appearance, but epithelial cell differentiation markers were distributed similarly in both strains. There was no evidence of excess extracellular matrix deposition or inflammation at the time points examined. In contrast, by adulthood MMP-2-/- mice had normal alveolar size and structure, indicating normal alveolar development was not dependent on the ability of MT1-MMP to activate pro-MMP-2. These data indicate that MT1-MMP is required for normal lung development.

Animals↗

Matrix metalloproteases in head and neck cancer.

Matrix metalloproteases (MMPs) are a collection of enzymes capable of cleaving extracellular matrix components, growth factors, and cell-surface receptors. MMPs modulate most aspects of tumorigenesis and are highly expressed in cancer compared with normal tissues. Preclinical studies have demonstrated that head and neck squamous cell carcinomas (HNSCCs) express high levels of MMPs in vivo and that inhibition of these enzymes in vitro and in mouse models decreases invasion and metastasis. However, the clinical trials for MMP inhibitors have failed to demonstrate a significant survival advantage in most cancers. The disparity between preclinical and clinical studies has led to the reevaluation of how MMP functions in cancer and the design of clinical trials for molecularly targeted agents. Mouse model data and analysis of HNSCC tumor specimens suggests that membrane type-1 MMP (MT1-MMP) may be a critical enzyme in tumor cell invasion and survival in vivo. This accumulated data provide evidence for development of selective MT1-MMP inhibitors as therapy in HNSCC.

Animals↗

Expression of membrane type 1 matrix metalloproteinase (MT1-MMP) in A2058 melanoma cells is associated with MMP-2 activation and increased tumor growth and vascularization.

Membrane-type metalloproteinase-1 (MT1-MMP) is a transmembrane metalloproteinase overexpressed in tumors, which plays a major role in the first step of pro-MMP-2 activation, leading to the generation of an intermediate 62 kDa species. The second step of MMP-2 activation that yields to the mature form is less understood and could involve an autocatalytic process and/or the activity of the plasminogen/plasmin system. Human melanoma A2058 cells, which express MMP-2 only in its pro-form, were used to determine the role of MT1-MMP during pericellular proteolysis and tumor progression. The induction of MT1-MMP overexpression by MT1-MMP cDNA transfection initiated the first step of MMP-2 activation. We provide evidence that a cooperation between the plasminogen/plasmin system and MT1-MMP endowed the cells with the ability to fully activate MMP-2 and with enhanced invasive properties in vitro. When injected subcutaneously in nude mice, MT1-MMP expressing clones induced rapid tumor growth and high tumor vascularization, while the control clones were poorly or not tumorigenic. Our data provide the first demonstration, in an experimental model, that MT1-MMP expression by tumor cells promotes tumor vascularization.

Animals↗

Anti-neovascular therapy by liposomal drug targeted to membrane type-1 matrix metalloproteinase.

Because membrane type-1 matrix metalloproteinase (MT1-MMP) is expressed specifically on the angiogenic endothelium as well as tumor cells, an agent possessing the ability to bind to this molecule might be useful as a tool for active targeting of tumor angiogenic vessels. Based on the sequences of peptide substrates of MT1-MMP, which had been determined by using a phage-displayed peptide library, we examined the binding ability of peptide-modified liposomes for endothelial cells and targeting ability for tumor tissues by positron emission tomography (PET). Liposomes modified with stearoyl-Gly-Pro-Leu-Pro-Leu-Arg (GPLPLR-Lip) showed high binding ability to human umbilical vein endothelial cells and accumulated in the tumor about 4-fold more than did the unmodified liposomes. Because we reported previously that liposomalized 5'-O-dipalmitoylphosphatidyl 2'-C-cyano-2'-deoxy-1-beta-D-arabino-pentofuranosylcytosine (DPP-CNDAC), a hydrophobized derivative of the novel antitumor nucleoside CNDAC, strongly suppressed tumor growth when delivered in liposomes modified with another angiogenic homing peptide, we examined the antitumor activity of DPP-CNDAC entrapped in GPLPLR-Lip. DPP-CNDAC/GPLPLR-Lip showed significant tumor growth suppression compared to DPP-CNDAC/unmodified liposomes. These results suggest that DPP-CNDAC-liposomes modified with MT1-MMP-targeted peptide are useful for cancer anti-neovascular therapy (ANET), namely, tumor growth suppression by damage to angiogenic endothelial cells.

Angiogenesis Inhibitors↗

Microvesicles derived from activated platelets induce metastasis and angiogenesis in lung cancer.

The role of platelets in tumor progression and metastasis has been recognized but the mechanism of their action remains unclear. Five human lung cancer cell lines (A549, CRL 2066, CRL 2062, HTB 183, HTB 177) and a murine Lewis lung carcinoma (LCC) cell line (for an in vivo model of metastasis) were used to investigate how platelet-derived microvesicles (PMV), which are circular fragments shed from the surface membranes of activated platelets, and exosomes released from platelet alpha-granules, could contribute to metastatic spread. We found that PMV transferred the platelet-derived integrin CD41 to most of the lung cancer cell lines tested and stimulated the phosphorylation of mitogen-activated protein kinase p42/44 and serine/threonine kinase as well as the expression of membrane type 1-matrix metalloproteinase (MT1-MMP). PMV chemoattracted 4 of the 5 cell lines, with the highly metastatic A549 cells exhibiting the strongest response. In A549 cells, PMV were shown to stimulate proliferation, upregulate cyclin D2 expression and increase trans-Matrigel chemoinvasion. Furthermore, in these cells, PMV stimulated mRNA expression for angiogenic factors such as MMP-9, vascular endothelial growth factor, interleukin-8 and hepatocyte growth factor, as well as adhesion to fibrinogen and human umbilical vein endothelial cells. Intravenous injection of murine PMV-covered LLC cells into syngeneic mice resulted in significantly more metastatic foci in their lungs and LLC cells in bone marrow than in control animals injected with LCC cells not covered with PMV. Based on these findings, we suggest that PMV play an important role in tumor progression/metastasis and angiogenesis in lung cancer.

Animals↗

Upregulation of matrix metalloproteinases (MMPs) in breast cancer xenografts: a major induction of stromal MMP-13.

In human breast cancer (HBC), as with many carcinoma systems, most matrix metalloproteinases (MMPs) are largely expressed by the stromal cells, whereas the tumour cells are relatively silent in MMP expression. To determine the tissue source of the most relevant MMPs, we xenografted HBC cell lines and HBC tissues into the mammary fat pad (MFP) or bone of immunocompromised mice and measured the expression of human and mouse MMP-2, -9, -11, -13, membrane-type-1 MMP (MT1-MMP), MT2-MMP and MT3-MMP by species-specific real-time quantitative RT-PCR. Our data confirm a stromal origin for most tumour-associated MMPs and indicate marked and consistent upregulation of stromal (mouse) MMP-13 and MT1-MMP in all xenografts studied, irrespective of implantation in the MFP or bone environments. In addition, we show increased expression of both human MMP-13 and human MT1-MMP by the MDA-MB-231 tumour cells grown in the MFP compared to in vitro production. MMP protein and activity data confirm the upregulation of MMP mRNA production and indicate an increase in the activated MMP-2 species as a result of tumour implantation. These data directly demonstrate tumour induction of MMP production by stromal cells in both the MFP and bone environments. These xenografts are a valuable means for examining in vivo production of MMPs and suggest that MMP-13 and MT1-MMP will be relevant targets for inhibiting breast cancer progression.

Animals↗

The hepatitis B virus X protein promotes hepatocellular carcinoma metastasis by upregulation of matrix metalloproteinases.

The hepatitis B virus (HBV) is a major cause of human hepatocellular carcinoma (HCC) which has a very high mortality rate due to high incidence of metastasis. It is unknown whether HBV contributes to HCC metastasis. In this report, we present clinical data obtained from HCC patients indicating that the expression of hepatitis B virus X protein (HBx) in HCC is associated with an increased expression of membrane-type 1 matrix metalloproteinase (MT1-MMP), and matrix metalloproteinase-2(MMP-2), which correlates with a poor prognosis. We further demonstrate experimentally that HBx upregulates MT1-MMP, which in turn induces MMP-2. Significantly, HBx-mediated MMP activation is associated with a marked increase of cell migration, as revealed by both wound-healing and transwell migration assays, suggesting that HBx may facilitate tumor cell invasion by upregulation of MMPs and subsequent destruction of the extracellular matrix. Together, our results support a model in which HBx contributes to HCC metastasis by upregulation of MMPs.

Carcinoma, Hepatocellular↗

MT1-MMP: a tethered collagenase.

Gene ablation in mice offers a powerful tool to assay in vivo the role of selected molecules. Numerous new mouse models of matrix metalloproteinases (MMP) deficiency have been developed in the past 5 years and have yielded a new understanding of the role of MMPs while also putting to rest assumptions based on data predating the days of mouse models. The phenotype of the MT1-MMP deficient mouse is one example which illustrates the sometimes rather surprising insights into extracellular matrix remodeling in development and growth that can be gained with mouse genetics. While MT1-MMP appears to play little or no role in embryonic development, loss of this enzyme results in progressive impairment of postnatal growth and development affecting both the skeleton and the soft connective tissues. The underlying pathologic mechanism is loss of an indispensable collagenolytic activity, which remains essentially uncompensated. Our findings demonstrate that growth and maintenance of the skeleton requires coordinated and simultaneous MT1-MMP-dependent remodeling of all soft tissue attachments (ligaments, tendons, joint capsules). We note that the phenotype of the MT1-MMP deficient mouse bears no resemblance to those of mice deficient in MMP-2 and tissue inhibitors of metallo-proteinase (TIMP)-2 all but dispelling the view that activation of MMP-2 by the MT1-MMP/TIMP-2/proMMP-2 axis plays a significant role in growth and development throughout life. It is of interest to note that loss of a single catabolic function such as selective collagen degradation mediated by MT1-MMP gives rise to profound impairment of a number of both anabolic and catabolic functions.

Animals↗

Expression pattern of four membrane-type matrix metalloproteinases in the normal and diseased mouse mammary gland.

Both mammary gland development and mammary carcinogenesis involve extensive remodeling of the mammary gland extracellular matrix. The expression of four membrane-type matrix metalloproteinases (MT-MMPs) with matrix remodeling potential in development and tumorigenesis was evaluated by in-situ hybridization on mouse mammary gland sections. MT1-MMP and MT3-MMP were found in the mammary stroma mainly around epithelial structures in both developing and mature mammary gland. In contrast, MT2-MMP was found exclusively in the mammary epithelium. Lactating gland expressed none of the examined MT-MMPs. Mammary gland tumors expressed MT1-MMP, MT2-MMP, and MT3-MMP while MT4-MMP was not expressed in any developmental or cancerous stage analyzed here. Our results suggest that MT1-MMP, MT2-MMP, and MT3-MMP may be involved in remodeling of both the normal and diseased mammary gland either directly or indirectly by activation of other MMPs.

Aging↗