Cell type specific interleukin‐6 induced responses in tumor keratinocytes and stromal fibroblasts are essential for invasive growth

Interleukin‐6 (IL‐6) is one of the major inflammatory interleukins that has been linked to cancer progression. In our model for human skin squamous cell carcinoma (SCC), IL‐6 expression is strongly upregulated upon progression from benign tumors to highly malignant, metastasizing SCCs. We now demonstrate that IL‐6 promotes malignant and invasive tumor growth in human skin SCCs by inducing cell type specific cytokine profiles in tumor keratinocytes and stromal fibroblasts, activating the latter towards a tumor associated fibroblast (TAF) phenotype. In three‐dimensional organotypic cocultures in vitro invasive growth of IL‐6 overexpressing tumor keratinocytes, is associated with increased expression of matrix metalloproteinase‐2 (MMP‐2), MMP‐14 and tissue inhibitor of metalloproteinases‐2, and clearly depends on IL‐6 activated fibroblasts. IL‐6‐induced secretion of monocyte chemotactic protein‐1 (MCP‐1) in tumor keratinocytes and of hepatocyte growth factor in fibroblasts is crucial for regulating expression and activation of MMP‐2. This functional role of IL‐6 is confirmed in vivo. Here MMP‐14 and MMP‐2 expression occur exclusively in surface transplants of IL‐6 overexpressing keratinocytes and fibroblasts are identified as important source of MMP‐2. Our data indicate that tumor keratinocytes derived IL‐6 activates stromal fibroblasts towards a TAF phenotype, promoting tumor invasion via enhanced expression and activation of MMP‐2.     

Localization of gelatinase-A and gelatinase-B mRNA and protein in human gliomas

Malignant gliomas maintain a poor prognosis and survival rate due to their marked local invasive growth and neovascularization. Matrix metalloproteinases (MMPs) have been implicated in glioma invasion and angiogenesis, but it is unknown whether they are produced by the tumor cells or surrounding stroma. Using in situ hybridization and immunohistochemistry, we found expression of mRNA for both gelatinase-A (MMP2) and gelatinase-B (MMP9) localized to tumor cells and vascular structures in glioma sections. Gelatinase-A protein expression was detected most prominently in tumor cells, with very little signal seen in vasculature. Gelatinase-B protein expression was prominent in vascular structures but was also expressed in tumor cells. Our data show that these proteases are produced by glioma cells and vascular structures and suggest that synthetic MMP inhibitors might be useful in this disease.     

Organ heterogeneity of host-derived matrix metalloproteinase expression and its involvement in multiple-organ metastasis by lung cancer cell lines

Cancer metastasis is tightly regulated by the interaction of tumor cells and host organ microenvironments. Matrix metalloproteinases (MMPs), produced by both tumor cells and host stromal cells, play a central role in tumor invasion and angiogenesis. We determined whether metastatic potential of lung cancer to multiple organs is dependent solely on the expression of MMPs by tumor cells, using two metastasis models of human lung cancer cell lines expressing various levels of MMPs and a MMP inhibitor (ONO-4817). In the lung metastasis model, tumor cells (PC14, PC14PE6, H226, A549) inoculated i.v. into nude or SCID mice metastasized only in the lung. In the multiple-organ metastasis model, tumor cells (RERF-LC-AI, SBC-3/DOX, H69/VP, which express low levels of MMPs) inoculated i.v. into natural killer cell-depleted SCID mice metastasized into the liver, kidneys, and systemic lymph nodes. Film in situ zymography analysis revealed that the nontumor parenchyma of the lung had no gelatinolytic activity, whereas gelatinolytic activity of the liver and kidney was high and low, respectively. In the lung metastasis model, gelatinolytic activity of lung nodules directly correlated with the in vitro expression of MMP-2 and MMP-9 by tumor cells. Inhibition of MMP activity by ONO-4817 suppressed lung metastasis by the cell lines that expressed MMPs, but not those that did not express MMP, via the inhibition of MMP activity of lung tumors. In the multiple-organ metastasis model, liver parenchyma, but not liver nodules, showed gelatinolytic activity. The MMP inhibition reduced metastasis to the liver, but not to the kidney or lymph nodes, via inhibition of MMP activity of liver parenchyma. These findings suggest that MMP expression varies among the host organ microenvironments and that stromal MMPs may promote metastasis of lung cancer. Therefore, antimetastatic effects based on MMP inhibition may be dependent on MMPs derived not only from tumor cells but also from organ-specific microenvironments.     

The other side of MMPs: Protective roles in tumor progression

The matrix metalloproteinase (MMP) family of extracellular proteinases have long been associated with cancer invasion and metastasis by virtue of their ability to collectively degrade all components of the extracellular matrix (ECM). The general belief that overexpression of a specific MMP, either by tumor cells or the surrounding stroma, is pro-tumorigenic led to the development of synthetic MMP inhibitors for the treatment of cancer. However, there is an increasing amount of literature demonstrating that the expression of certain MMPs, either at the primary or the metastatic site, provides a beneficial and protective effect in multiple stages of cancer progression. Here, we review the evidence for protective effects of MMPs and contrast this with pro-tumorigenic effects of either the same enzyme, or a different MMP of the same family. These studies highlight the importance of targeting specific MMPs for cancer treatment, and point to a potential reason why clinical trials of pharmaceutical inhibitors for MMPs were disappointing. In order to effectively target MMPs in cancer progression, a better understanding of both their pro- and anti-tumorigenic effects is required.     

Distinct pattern of matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 mRNA expression in human colorectal cancer and liver metastases.

The matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are perceived as essential for tumour invasion and metastasis. In the present study, we compare the topographical pattern of MMP-9 and TIMP-1 expression in colorectal cancer and liver metastasis by in situ hybridisation. TIMP-1 mRNA was detected in all 26 colorectal cancers examined, while only 18 out of 26 (69.2%) were positive for MMP-9. Both MMP-9 and TIMP-1 mRNA were observed in all ten liver metastases but were absent in three adenomas and in all normal colonic mucosa and liver. There was no association between MMP-9 or TIMP-1 mRNA expression and degree of differentiation or size of Tumours. MMP-9 and TIMP-1 mRNA were similarly observed in the peritumour stroma cells rather than in tumour cells themselves. MMP-9 mRNA positive cells were round and identified as macrophages by immunostaining with an anti-macrophage antibody (KP1), while TIMP-1, mRNA was detected in spindle-shaped stromal cells. In liver metastases, MMP-9 localised within peritumour stroma or at the interface between the tumour stroma and normal liver, whereas TIMP-1 mRNA was located throughout the malignant tumour stroma. Our data demonstrate a distinct pattern of MMP-9 and TIMP-1 mRNA expression in colorectal cancer and liver metastases suggesting distinct cellular origins as well as separate patterns of regulation.     

Prominent expression of metalloproteinases in early stages of ovarian tumorigenesis

The role for matrix metalloproteinases (MMPs) in tumor cells invasion and metastasis is well established, and expression of MMPs is recognized as an indication of tumor cell malignancy. Previous studies suggest that the degradation of the basement membrane is a crucial early step in epithelial transformation and ovarian tumorigenesis. Thus, MMPs may also express and exert a role in preneoplastic lesions of ovarian tissues. We investigated the expression of the major metalloproteinases, gelatinase A, 72 kDa type IV collagenase (MMP-2), and gelatinase B, 92 kDa type IV collagenase (MMP-9), and the presence of basement membrane in ovarian tumors and tissues from prophylactic oophorectomies using immunostaining. MMP expression was also characterized in a panel of ovarian cancer cell lines and several nontumorigenic ovarian surface epithelial primary cells by zymography, Northern, and Western blots. We found, surprisingly, that MMP-2 and MMP-9 are expressed more frequently in early lesions than in established carcinomas. No correlation was found between the expression of MMPs and tumor grades or stages. In preneoplastic lesions, MMP-2 or MMP-9 expression often associates with the absence of basement membrane and morphological alterations. MMP-2 is often expressed in nontumorigenic ovarian surface epithelial cells but reduced or absent in cancer cells. Thus, we conclude that MMPs expression does not correlate with the malignancy of ovarian epithelial cells as generally thought. Rather, increased metalloproteinase expression is an early event in ovarian tumorigenesis and associates with the loss of epithelial basement membrane and morphological transformation. We propose that the increased MMP activity is an etiological factor for ovarian cancer risk. We found that MMPs expression does not correlate with the malignancy of ovarian epithelial cells as generally thought. Rather, increased metalloproteinase expression is an early event in ovarian tumorigenesis. The finding suggests roles of MMP in tumor initiation in addition to invasion, and may impact on the strategy for use of MMP inhibitors in cancer prevention.     

Matrix metalloproteinases and tumor metastasis

Functions of individual matrix metalloproteinases (MMPs) differentially expressed by tumor cells and stromal cells, are finely regulated by their spatial as well as temporal interactions with distinct cellular and extracellular components of the tumor microenvironment and also distant pre-metastatic sites. Certain aspects of MMP involvement in tumor metastasis such as tumor-induced angiogenesis, tumor invasion, and establishment of metastatic foci at the secondary site, have received extensive attention that resulted in an overwhelming amount of experimental and observational data in favor of critical roles of MMPs in these processes. In particular, dependency of tumor angiogenesis on the activity of MMPs, especially that of MMP-9, renders this step possibly the most effective target of synthetic MMP inhibitors. MMP functioning in other stages of metastasis, including the escape of individual tumor cells from the primary tumor, their intravasation, survival in circulation, and extravasation at the secondary site, have not yet received enough consideration, resulting in insufficient or controversial data. The major pieces of evidence that are most compelling and clearly determine the role and involvement of MMPs in the metastatic cascade are provided by molecular genetic studies employing knock-out or transgenic animals and tumor cell lines, modified to overexpress or downregulate a specific MMP. Findings from all of these studies implicate different functional mechanisms for both tumor and stromal MMPs during distinct steps of the metastatic cascade and indicate that MMPs can exhibit pro-metastatic as well as anti-metastatic roles depending on their nature and the experimental setting. This dual function of individual MMPs in metastasis has become a major focus of this review.     

Matrix metalloproteinases in tumor invasion and metastasis

Extensive work on the mechanisms of tumor invasion and metastasis has identified matrix metalloproteinases (MMPs) as key players in the events that underlie tumor dissemination. Studies using natural and synthetic MMP inhibitors, as well as tumor cells transfected with cDNAs encoding the MMPs characterized thus far have provided compelling evidence that MMP activity can induce or enhance tumor survival, invasion and metastasis. Because of the ability of MMPs to degrade extracellular matrix (ECM) proteins, the principal mechanism whereby MMPs promote tumor development has been thought to be the proteolytic breakdown of tissue barriers to invasion and the associated facilitation of circulating tumor cell extravasation. However, recent evidence stemming from the use of novel experimental approaches indicates that MMPs do not play a major role in the process of extravasation itself. Rather, they appear to promote intravasation (the process of penetrating the circulation following invasion of blood vessels) and regulate the relationship between tumor cells and host tissue stroma subsequent to extravasation. In addition, the discoveries that a growing number of proteolytically active MMPs may localize to the cell surface in association with adhesion receptors, and that MMP substrates include latent cytokines and growth factors, provide a new conceptual framework for the mechanisms whereby MMPs influence tumor behavior.     

Reversion of tumor phenotype in surface transplants of skin SCC cells by scaffold-induced stroma modulation

Interactions between cancer cells and the tissue microenvironment play an essential role in controlling tumor development and progression. Here, we report that stromal modulation induced by a biodegradable meshwork (Hyalograft 3D) inhibited tumor vascularization and invasion of the locally invasive low-grade malignant human HaCaT-ras II-4 keratinocytes in a surface xenotransplantation assay. The scaffold caused formation of an active granulation tissue that shifted to a fibrotic-type connective tissue with accumulation of myofibroblasts and collagen bundles. Most importantly, in transplants with scaffolds, the epithelial-stromal border was normalized developing an ultrastructurally complete basement membrane (BM) including hemidesmosomes. The observed reversion of the tumor phenotype was not due to decreased tumor cell proliferation but correlated with (i) normalization of epidermal differentiation, (ii) condensation of extracellular matrix (ECM) and (iii) reduction of peritumoral protease activity Furthermore, inhibited invasion was paralleled by eliminated tumor vascularization. This was substantiated by a diminished endothelial VEGF-receptor (VEGFR) expression and, in turn, by a concomitant increase in the ECM components thrombospondin-1 (TSP-1) and endostatin, known to impair angiogenesis. Even in transplants of the metastatic high-grade malignant HaCaT-ras A-5RT3 keratinocytes the anti-invasive effect of the scaffold-modulated stroma prevailed. Tumor vascularization and invasion was reduced and the epithelial tissue partially normalized including formation of stretches of BM. This clearly demonstrates that the scaffold-modulated connective tissue not only blocks tumor invasion but reverts the tumor phenotype. These novel findings underline the controlling function of tumor stroma and open new strategies of cancer therapy by targeting tumor stroma elements.     

Matrix metalloproteinases: biologic activity and clinical implications.

Tumor progression is a complex, multistage process by which a normal cell undergoes genetic changes that result in phenotypic alterations and the acquisition of the ability to spread and colonize distant sites in the body. Although many factors regulate malignant tumor growth and spread, interactions between a tumor and its surrounding microenvironment result in the production of important protein products that are crucial to each step of tumor progression. The matrix metalloproteinases (MMPs) are a family of degradative enzymes with clear links to malignancy. These enzymes are associated with tumor cell invasion of the basement membrane and stroma, blood vessel penetration, and metastasis. They have more recently been implicated in primary and metastatic tumor growth and angiogenesis, and they may even have a role in tumor promotion. This review outlines our current understanding of the MMP family, including the association of particular MMPs with malignant phenotypes and the role of MMPs in specific steps of the metastatic cascade. As scientific understanding of the MMPs has advanced, therapeutic strategies that capitalize on blocking the enzymes have rapidly developed. The preclinical and clinical evolution of the synthetic MMP inhibitors (MMPIs) is also examined, with the discussion encompassing important methodologic issues associated with determining clinical efficacy of MMPIs and other novel therapeutic agents.     

Macrophage migration inhibitory factor promotes the invasion and metastasis of oral squamous cell carcinoma through matrix metalloprotein‐2/9

Macrophage migration inhibitory factor (MIF) has been shown to closely associate with the malignant progression of a variety of human carcinomas. However, the role and its underlying molecular mechanisms of MIF in the invasion and metastasis of oral squamous cell carcinoma (OSCC) still remains unclear. Here, we found that MIF silencing reduced the cell proliferation, migration, and invasion, as well as matrix metalloprotein‐2 (MMP‐2) and MMP‐9 in OSCC cells. Overexpression of MMP‐2 or MMP‐9 restored the migration and invasion of MIF‐knockdown cells, indicating that MMP‐2 and MMP‐9 are downstream targets of MIF. In the xenograft model, MIF silencing inhibited tumor growth and in lymph metastasis model, MIF silencing reduced tumor metastasis. More importantly, immunohistochemistry staining in a tissue microarray (TMA) demonstrated that MIF expression was positively correlated with clinic stage, recurrence, metastasis, and poor prognosis of patients with OSCC as well as with the levels of MMP‐2 or MMP‐9 in TMA. Therefore, our findings suggest that MIF may promote the invasion and metastasis of OSCC through the activation of MMP‐2 and MMP‐9 and prompt further investigation into the therapeutic value of MIF for OSCC treatment.     

Retinoic acid modulates the ability of macrophages to participate in the induction of the angiogenic phenotype in head and neck squamous cell carcinoma

Collagenase-3 (MMP-13) is characterized by an exceptionally wide substrate specificity and restricted expression. MMP-13 is 1 of the few MMPs primarily expressed by tumor cells in malignant tumors, e.g., squamous cell carcinomas and its expression correlates with their invasion capacity. In this work, we have constructed an expression vector and a recombinant adenovirus harboring human MMP-13 cDNA to investigate the role of MMP-13 in cancer cell invasion. Our results show that constitutive expression of MMP-13 by HT-1080 cells stably transfected with MMP-13 expression vector or transduced with MMP-13 adenovirus markedly increased their invasion both through type I collagen and reconstituted basement membrane (Matrigel) with no alterations in expression or activation of collagenase-1 (MMP-1), gelatinase-A (MMP-2), or gelatinase-B (MMP-9). The enhanced invasion capacity of MMP-13 expressing HT-1080 cells was dependent on MMP activity, as it was blocked by MMP inhibitor Batimastat (BB-94) and tissue inhibitor of metalloproteinases-3 (TIMP-3). Our data provide direct evidence for the role of MMP-13 as a potent invasion proteinase, which alone can enhance the ability of malignant cells to penetrate through both basement membrane and fibrillar collagen.     

Tumor marker potential of serum matrix metalloproteinases in patients with head and neck cancer

BACKGROUND: Elevated expression of matrix metalloproteinases (MMPs) is suggested to have tumor marker potential in various tumors. MMPs are capable of disintegrating the basement membrane, which is a main characteristic of tumor invasion. They are specifically inactivated by tissue inhibitors of metalloproteinases (TIMPs). Squamous cell carcinomas of the head and neck (SCCHN) are known to be highly invasive tumors with early locoregional metastatic spread. PATIENTS AND METHODS: To investigate the tumor marker potential of MMPs in SCCHN, MMP-2, -3, -8, -9, -13 and TIMP-1 serum levels were determined in 73 patients and compared to 74 controls. A correlation with T- and N-status, UICC-staging and grading was performed. Additionally, the influence of inflammation on the MMP serum concentration was examined. RESULTS: Significant differences between patients with SCCHN and controls were seen for MMP-3, -8 and -9. A significant correlation was found between MMP-8 concentration and T-status, N-status and UICC-staging. No correlation with the grading of the tumor was observed. Inflammatory diseases did not affect MMP and TIMP levels significantly. CONCLUSION: Some MMPs are elevated in the serum of patients with SCCHN and especially MMP-8 showed interesting tumor marker potential.     

基质金属蛋白酶和金属蛋白酶的组织抑制物在人胰腺癌的基因表达

观察胰腺组织及其癌变标本中基质金属蛋白酶（ＭａｔｒｉｘＭｅｔａｌｌｏｐｒｏｔｅｉｎａｓｅｓ,ＭＭＰｓ）和金属蛋白酶的组织抑制物（ＴｉｓｓｕｅＩｎｂｉｉｔｏｒｓｏｆＭｅｔａｌｌｏｐｏｔｅｉｍａｓｅｓ,ＴＩＭＰｓ）基因表达的变化关系,以探讨ＭＭＰｓ在肿瘤侵袭和转移过程中的作用。方法：用原位杂交（ｉｎｓｉｔｕｈｙｂｒｉｄｉｚａｔｉｏｎ,ＩＳＨ）方法,采用ＣＤＮＡ探针（ＭＭＰ２,ＭＭＰ９,ＴＩＭＰ１）对两     

基质金属蛋白酶MMP-9、2及其抑制物TIMP-1、2在侵袭性垂体腺瘤生物学行为中的意义

背景与目的:通常垂体腺瘤在组织学上属良性肿瘤,但仍有部分肿瘤侵犯周围组织,形成侵袭性肿瘤,垂体腺瘤侵袭的生物学机制尚不清楚。垂体腺瘤血管丰富,而血管形成与肿瘤侵袭都需要细胞外基质成份的降解和细胞移动,这一过程中基质金属蛋白酶(matrixmetalloproteinases,MMP)和它们的天然抑制物-组织金属蛋白酶抑制剂(tissueinhibitorsofmetalloproteinases,TIMP)有可能起着关键作用。本研究拟通过检测MMP-9和MMP-2及其抑制因子TIMP-1和TIMP-2在非侵袭性垂体瘤和侵袭性垂体瘤中的表达,探讨垂体腺瘤的侵袭机制。方法:收集垂体瘤手术切除标本61例,分为侵袭组(49例)和非侵袭组(12例)。采用免疫组织化学SP法检测,并根据阳性细胞占肿瘤细胞总数的比率进行半定量非参数检验分析。结果:MMP-9、TIMP-1、MMP-2和TIMP-2在侵袭性垂体瘤中表达的阳性率分别为95.9%(47/49),57.1%(28/49),75.5%(37/49),和89.8%(44/49);在非侵袭性垂体瘤中阳性率分别为100%(12/12),91.7%(11/12),66.7%(8/12)和91.7%(11/12)。TIMP-1和TIMP-2的表达在侵袭性垂体瘤组明显少于非侵袭性垂体瘤组,(P<0.05);MMP-2在侵袭性垂体瘤组有增加的趋势,但无统计学意义,(P>0.05)。结论:在垂体腺瘤的侵袭性生物学机制中组织金属蛋白酶抑制剂TIMP-1和TIMP-2有可