An essential part for Rho-associated kinase in the transcellular invasion of tumor cells

Adhesion of tumor cells to host cell layers and subsequent transcellular migration are pivotal steps in cancer invasion and metastasis. The small GTPase Rho controls cell adhesion and motility through reorganization of the actin cytoskeleton and regulation of actomyosin contractility. Cultured rat MM1 hepatoma cells migrate through a mesothelial cell monolayer in vitro in a serum-dependent, Rho-mediated manners. Among several proteins isolated as putative target molecules of Rho, the ROCK (ROK) family of Rho-associated serine-threonine protein kinases are thought to participate in the induction of focal adhesions and stress fibers in cultured cells, and to mediate calcium sensitization of smooth muscle contraction by enhancing phosphorylation of the regulatory light chain of myosin. Transfection of MM1 cells with cDNA encoding a dominant active mutant of ROCK conferred invasive activity independently of serum and Rho. In contrast, expression of a dominant negative, kinase-defective ROCK mutant substantially attenuated the invasive phenotype. A specific ROCK inhibitor (Y-27632) blocked both Rho-mediated activation of actomyosin and invasive activity of these cells. Furthermore, continuous delivery of this inhibitor using osmotic pumps considerably reduced the dissemination of MM1 cells implanted into the peritoneal cavity of syngeneic rats. These results indicate that ROCK plays an essential part in tumor cell invasion, and demonstrate its potential as a therapeutic target for the prevention of cancer invasion and metastasis.     

Cellular and molecular mechanisms of tumor invasion

This review summarizes data on cellular and molecular mechanisms underlying phenotypical characteristics of tumor cells that determine their ability for invasion. These mechanisms include dysregulation of adhesive interactions of tumor cells with each other and with extracellular matrix, protease production, locomotion reactions of tumor cells, and induction of angiogenesis in tumor. Data on structure and functions of transmembrane adhesion molecules and their ligands, molecular composition of adhesion structures (intercellular and focal contacts), and role of adhesion molecules as transducers of intracellular signals are considered. Alterations of expression of adhesion molecules and cytoplasmic proteins in adhesion structures and hyperphosphorylation of these molecules by oncogene products are described as a precondition of invasion activity of tumor cells. The contact interaction between circulating tumor cells and vascular endothelium is considered as the important stage of the metastatic process. Secretion of proteases by tumor cells and regulation of their activity by specific stromal inhibitors are described. Function of motogens in the acquisition by a tumor cell of locomotor phenotype facilitating invasion and impairments of topographic reactions of cells playing an important role in the invasion are considered. Attention is given to mechanisms of neoangiogenesis in the tumor providing additional ways for dissemination of tumor cells.     

The human myoepithelial cell is a natural tumor suppressor

Myoepithelial cells, which surround ducts and acini of glandular organs, form a natural border separating proliferating epithelial cells from basement membrane and underlying stroma. Myoepithelial cells in situ and in vitro constitutively express high amounts of proteinase inhibitors that include tissue inhibitor of metalloproteinase 1, protease nexin-II, alpha-1 antitrypsin, and maspin. Human myoepithelial xenografts (HMS-X, HMS-3X, and HMS-4X), which our laboratory has established, accumulate an abundant extracellular matrix containing sequestered proteinase inhibitors. Humatrix, a gel that we have derived from HMS-X, inhibits tumor cell invasion (down to 25% +/- 10% of Matrigel control; P < 0.01), and our recently established human myoepithelial cell lines, HMS-1, HMS-3, and HMS-4, inhibit tumor cell invasion in cellular invasion (down to 42% +/- 7% of control; P < 0.05) and in conditioned media assays (down to 30% +/- 8% of control; P < 0.01). The anti-invasive effects of HMS-1, HMS-3, and HMS-4 can be enhanced by phorbol 12-myristate 13-acetate (down to 2% +/- 1% of control) by a maspin-dependent mechanism and abolished by dexamethasone (up to 95% +/- 5% of control) by a maspin-independent mechanism (P < 0.01). HMS-X, HMS-3X, HMS-4X, and Humatrix inhibit tumor invasion and metastasis in severe combined immunodeficient mice (P < 0.001). The cumulative data suggest that myoepithelial cells are natural paracrine suppressors of invasion and metastasis and may specifically inhibit the progression of precancerous disease states to invasive cancer in vivo.     

Developmental stages in experimental liver metastases: relation to invasiveness

We have previously reported that an invasive morphotype can be evoked in a rat colon carcinoma by transplanting it into pre-induced subcutaneous granulation tissue. We have now studied the interaction of the same tumor with liver tissue, which is extremely poor in connective tissue in comparison with the subcutaneous site. Tumor cells were injected into the portal system and the resulting experimental liver metastases were examined by electron microscopy and immunohistochemistry. Early metastases consisted of well-differentiated acini, fully surrounded by connective tissue that was derived from the periportal stroma. In a later stage, this connective tissue was overgrown by tumor cells and, almost immediately, acinar differentiation was lost. Most metastases eventually reached the liver capsule, which reacted by forming a layer of granulation tissue. Only in this layer, we observed invasion by thin tumor cell strands, which were often intimately associated with fibroblasts or with blood capillaries. The tumor cells remained smooth and rounded during this process. After fully penetrating the granulation tissue, the tumor cell strands reached the liver surface, where they formed poorly structured papillary masses that were nearly devoid of stroma. Our observations indicate that, even in a relatively homogeneous organ like the liver, the tumor-host interaction is highly complex and dynamic. They also confirm the notion that granulation tissue stimulates tumor invasiveness. Finally, they show that tumor cells can actively invade host tissues without exhibiting a "fibroblastic" morphology.     

Invasive keratoacanthoma of the eyelid and ocular adnexa

PURPOSE: To report three patients with superficially invasive crateriform squamous proliferations of periocular tissue. METHODS: The authors identified three patients with superficially invasive periocular tumors that had clinical features of keratoacanthoma. Clinical histories, radiographs, and surgical pathologic specimens were reviewed. RESULTS: All three tumors arose over several weeks, had a crateriform configuration, and exhibited superficial invasion of underlying tissues, including perineural invasion and infiltration into skeletal muscle. All three tumors were classified as invasive keratoacanthoma. One tumor exhibited late perineural extension into the cavernous sinus and convincing histologic features consistent with squamous cell carcinoma. CONCLUSION: The clinical importance of recognizing invasive keratoacanthoma is that although the tumor has the potential for spontaneous involution, locally aggressive behavior with deep perineural invasion is possible. This tumor is considered to represent a variant of squamous cell carcinoma. The authors recommend complete surgical excision of crateriform squamous proliferations with frozen section control of margins of resection.     

Suppression of matrilysin inhibits colon cancer cell invasion in vitro

Matrilysin is a member of the matrix metalloproteinase gene family, which is believed to play an important role in tumor invasion and metastasis. We examined the effects of over- and under-expression of matrilysin on the ability of colon cancer cells to migrate across an artificial membrane in vitro. Introduction of matrilysin caused colon cancer cells to become more invasive as assessed by an in vitro invasion assay. In contrast, expression of matrilysin was down-regulated by all trans-retinoic acid or by introduction of anti-sense matrilysin in BM314 colon cancer cells. This down-regulation caused these cells to become less invasive. We demonstrated a correlation between matrilysin level and the invasive potential of human colon cancer cells, implying an important role for matrilysin in the control of tumor invasion in vitro.     

Detection of brain tumor invasion and micrometastasis in vivo by expression of enhanced green fluorescent protein

OBJECTIVE: To determine whether fluorescence from human brain tumor cells transfected with the enhanced green fluorescent protein (EGFP) gene in vitro and xenotransplanted into the brain of nude mice would permit the detection of brain tumor invasion and metastasis in vivo. METHODS: Daoy medulloblastoma cells were transfected with a long terminal repeat-based retroviral vector containing the EGFP gene. Stable EGFP-expressing clones were isolated and stereotactically injected into the frontal cortex of nude mice. Four weeks later, whole brain sections were examined using fluorescence microscopy, immunohistochemistry, and routine hematoxylin and eosin staining for the visualization and detection of tumor cell invasion and metastasis. RESULTS: We demonstrate that EGFP-transduced Daoy cells maintain stable high-level EGFP expression in the central nervous system during their growth in vivo. EGFP fluorescence clearly demarcated the primary tumor margins and readily allowed for the visualization of distant micrometastases and local invasion on the single-cell level. Small metastatic and locally invasive foci, including those immediately adjacent to the tumor's leading invasive edge, were virtually undetectable by routine hematoxylin and eosin staining and immunohistochemistry. EGFP expression also persisted in vitro after cell reculture from brain tissue extracts. CONCLUSION: We show, for the first time, that EGFP-transduced human brain tumor cells can be visualized by fluorescence microscopy after intracerebral implantation. This method is superior to routine hematoxylin and eosin staining and immunohistochemistry for the detection and study of physiologically relevant patterns of brain tumor invasion and metastasis in vivo.     

Role of proteases in tumor invasion and metastasis

Cancer remains a major cause of worldwide deaths due to ability of cancer cells to form secondary tumors at other sites by multistep process called metastasis. In order to migrate from their original site, tumor cells have to cross several barriers like basement membranes, interstitial tissues and extracellular matrices, which are composed primarily of collagen, proteoglycans, elastin, laminin and other glycoproteins. Tumor cells over express and secrete proteases which are capable of degrading the components of these barriers and thus facilitate their migration. The classes of proteases which have been implicated in the process of tumor invasion and metastasis include metalloproteases, serine proteases and cathepsins. Cancer cells in general have elevated levels of proteases belonging to more than one class. In some studies, process of invasion has been inhibited by using specific inhibitors of these proteases. Expression of some proteases has been observed only in some specific tumors. These proteases have been proposed to be of diagnostic/prognostic value. However a better understanding of the process of metastasis and tumor invasion is required before proteases can be used as therapeutic targets for blocking the spread of cancer.     

Growth hormone improves cardiac function in rats with experimental myocardial infarction

Glioblastoma multiforme is a highly invasive primary brain tumor, which is known to strongly express the CD44 cell adhesion receptor. A number of experimental studies suggest that the interaction of this receptor with extracellular matrix (ECM) proteins such as hyaluronic acid may in part mediate human glioma cell adhesion and invasion of brain tissue. Although the expression of CD44 and its spliced variants in brain tumors have been extensively studied, there have been no reports localizing its expression to the invasive margin of the tumor. The authors used immunoelectron microscopy to investigate the expression patterns of CD44 in an in vitro organotypic invasion assay. Tumor spheroids initiated from the U373 MG human glioblastoma line were confronted with fetal rat brain aggregates in a spheroid coculture system. The CD44 expression appeared at the interface between glioblastoma tumor spheroids and brain tissue, as well as in the spheroid itself. CD44 immunoreactivity was not detectable in mature 21-day fetal brain aggregates. The findings provide direct evidence that CD44 is expressed at the confrontational invasive border between glioblastomas and brain tissue, further supporting its role in glioma cell-ECM recognition and attachment.     

Role of the plasminogen activator and matrix metalloproteinase systems in epidermal growth factor- and scatter factor-stimulated invasion of carcinoma cells

Normal as well as neoplastic cells traverse extracellular matrix barriers by mobilizing proteolytic enzymes in response to epidermal growth factor (EGF)-EGF receptor (EGFR) or hepatocyte growth factor/scatter factor (SF)-c-Met interactions. The plasminogen activator-plasminogen axis has been proposed to play a key role during cell invasion, but the normal development of plasminogen activator- as well as that of plasminogen-deficient mice supports the existence of alternate proteolytic systems that permit cells to traverse extracellular matrix barriers. To characterize the role that matrix-degrading proteinases play in EGF- or SF-stimulated invasion, a human squamous carcinoma cell line (UM-SCC-1) was triggered atop the matrices of type I collagen or human dermal explants in a three-dimensional culture system. During EGF- or SF-induced invasion, UM-SCC-1 cells expressed urokinase-type plasminogen activator (uPA) and uPA receptor as well as the matrix metalloproteinases (MMPs), membrane-type MMP-1, collagenase 1, stromelysin 1, and gelatinase B. Despite the presence of a positive correlation between uPA receptor-uPA expression and growth factor-stimulated invasion, UM-SCC-1 invasion was not affected by inhibitors directed against the plasminogen activator-plasminogen axis. In contrast, both recombinant and synthetic MMP inhibitors completely suppressed invasion by either EGF- or SF-stimulated cells without affecting either proteinase expression or cell motility across collagen-coated surfaces. These data demonstrate that MMPs, but not the plasminogen activator-plasmin system, can directly regulate the ability of either EGF- or SF-stimulated tumor cells to invade interstitial matrix barriers.     

Development of a novel human extracellular matrix for quantitation of the invasiveness of human cells

During the crucial stages of tumor cell invasion and metastasis, neoplastic cells must traverse extracellular matrices for their migration to distant sites. Because basement membranes (BM) serve as a critical barrier to such passages, most previous in vitro assay models have utilized either an intact BM or a reconstituted rodent or avian BM-matrix to study this process. We have created a gel-like extracellular matrix derived from human amnions which contained type IV collagen, laminin, entactin, tenascin and heparan sulfate proteoglycan. This matrix, which we called Amgel, was used to study selected steps of invasion including cell attachment to matrix, degradation of it by proteolytic enzymes and movement of human tumor cells through matrix defects. An efficient tumor invasion assay system was developed utilizing filter-supported uniform coatings of this matrix in chambers. Human tumor cells (HT-1080 fibrosarcoma and RL-95 adenocarcinoma), when seeded onto Amgel-coated membranes, attached to matrix within 2 h and initiated a time-dependent migration and invasion process, as verified by biochemical analysis and both light and electron microscopy. In an optimized invasion assay 12-15% of tumor cells completely traversed the matrix during a 72-h period with > 90% viability. In contrast to these highly-invasive cells, normal human foreskin fibroblasts and normal human endometrial stromal cells exhibited minimal migration/matrix penetration during the same time period. When the Amgel-selected tumor cells (i.e. those penetrating the barrier) were isolated, subcultured, and re-exposed to Amgel, they had heightened invasiveness (2-3-fold) as compared to the parental cells. Thus, this improved 'all human' system for quantitating the invasive ability of tumor cells may provide a valuable tool in dissecting out the mechanistic underpinnings of human metastasis. In addition, this assay has the ability to screen agents which have potential anti-invasive and by extension anti-metastatic, activity or chemotactic properties.     

Correlation of very late activation integrin and CD44 expression with extrarenal invasion and metastasis of renal cell carcinomas

Cell adhesion molecules mediate cell-cell and cell-matrix interactions, and they are thought to play an important role in tumor invasion and metastasis. Altered expression of integrins and CD44 in renal cell carcinoma has been recently demonstrated, but an association with invasive or metastatic behavior has not been reported. We examined very late activation (VLA) integrin and CD44 expression in 37 renal cell carcinomas and correlated adhesion molecule expression with multiple histological and clinical parameters. Most tumors exhibited positive staining for VLA3 (81%). Approximately one third of the tumors stained positively for VLA6 and CD44, and fewer (27%) were positive for VLA2. Only a few tumors were positive for VLA4 (8%) and VLA5 (14%). Most of the tumors exhibiting positive staining showed a combination of membranous and cytoplasmic staining patterns. Low-grade tumors positive for VLA6 showed a tendency for basilar staining of the tumor cells, whereas high-grade tumors exhibited diffuse cytoplasmic staining. All tumors exhibiting weak or strong positive staining for VLA4 or VLA5 showed extrarenal invasion or were known to have developed metastases at the time of nephrectomy. All tumors strongly positive for VLA2 or CD44 showed invasion beyond the renal capsule or metastases. In contrast to a previous study, no association was observed between positive staining and tumor grade. Nor were tumor size, architectural pattern, cell type, or DNA ploidy found to be associated with particular staining patterns. Although many of the invasive tumors showed no difference in VLA integrin or CD44 expression compared with tumors confined to the kidney, increased expression in some of them suggests that these cell adhesion molecules may contribute to the invasive or metastatic phenotype.     

An experimental model for ovarian tumor invasion of cultured mesothelial cell monolayer

BACKGROUND: Peritoneal spread of tumor cells is one of the characteristic features of biologic behavior of ovarian cancers. To understand the mechanism by which human tumor cell invasion takes place, we have tried to establish an in vitro experimental model for ovarian tumor cell invasion of the mesothelial cell monolayer. EXPERIMENTAL DESIGN: Mesothelial cells were isolated from normal rat mesentery by trypsin digestion and the cells (1 x 10(5)/dish) were cultured in Eagle's minimum essential medium supplemented with 10% fetal calf serum. Cultured mesothelial cells (M cells) grew forming a pavement-like monolayer. When M cells grew to a confluent state, tumor cells (1 x 10(5)/dish) were seeded on M cell monolayers and cultured. Four tumor cell lines derived from human ovarian cancers were tested for their invasive behaviors. The penetration of M cell monolayers by the tumor cells was confirmed by a perpendicular section of the cell layers. The number of penetrated single tumor cells and colonies/cm2 was counted under a phase contrast microscope after the tumor cell seeding. RESULTS: Several hours after the tumor cell seeding, the cells adhered to M cell monolayers and started to penetrate by extending pseudopodia-like cytoplasmic processes through junctional margins of neighboring M cells, resulting in the formation of penetrated single tumor cells that then proliferated to form colonies under the monolayer. The number of penetrated single tumor cells and colonies/cm2 increased up to 24 hours after the tumor cell seeding, and thereafter stayed almost constant. The number increased with the number of tumor cells seeded, when counted at 48 hours, and therefore was taken to be the number of tumor cells invaded. The in vitro invasiveness of tumor cells varied with the tumor cell lines examined. CONCLUSIONS: Application of this system appears to provide rapid determinations of the invasive potential of ovarian tumor cells and to make it easy to screen substances that modify the invasion of mesothelial cells.     

In vitro pore-forming activity of the lantibiotic nisin. Role of protonmotive force and lipid composition

Human prostate cancer displays a high degree of variability in its rate of spread, which could be due largely to differences in the invasive potential of the tumor cells. The degradation of the basal lamina and stromal extracellular matrix is mediated in part by the secretion of matrix metalloproteinases (MMPs). Matrilysin (PUMP-1, MMP-7) and gelatinase A (M(r) 72,000 type IV collagenase, MMP-2) have been shown to be overexpressed in prostate carcinoma. We have expressed the single MMP matrilysin in the tumorigenic but nonmetastatic human prostate tumor cell line DU-145 to determine if matrilysin has a functional role in prostate tumor cell invasion. DU-145 cells expressing matrilysin were significantly more invasive than vector-only transfected cell lines as assayed by a severe combined immunodeficient mouse model of tumor cell invasion. Vector-only transfected DU-145 cells injected i.p. into severe combined immunodeficient mice invaded the diaphragm in only 1 of 9 mice (11%), whereas matrilysin-transfected DU-145 cells invaded the diaphragm in 12 of 18 mice (66%). The difference between the controls and matrilysin-transfected cells was statistically significant (P < 0.006). These results suggest a functional role for matrilysin in the initial invasion of prostate cancer through the epithelial basal lamina and into the surrounding stroma.     

A heterologous in vitro coculture system to study interaction between human bladder cancer cells and fibroblasts

Three-dimensional multicellular spheroids of two fibroblast cell lines (WI-38 and N1) and two differently differentiated bladder carcinoma cell lines (RT4 and J82) were used for cocultures of multicellular tumor spheroids with multicellular spheroids of fibroblasts. The aim of the study was the establishment and characterization of a standardized three-dimensional model for studies of tumor cell-fibroblast interaction as one aspect of tumor-stromal cell interactions of in vivo tumor tissue. Interaction of multicellular spheroids of both fibroblast cell types was analyzed by staining with antibodies against cytokeratin, vimentin and different extracellular matrix molecules. Further, proliferation assessment and phenotypic characterization of the cocultures are presented. Interactions varied with tumor cell type and fibroblast cell type, reflecting intrinsic properties of tumor cells and fibroblasts. The coculture of tumor cells with N1 reflected the in vivo situation the closest, since invasive properties of J82 as well as noninvasive properties of RT4 were characteristics seen in coculture.     

Inhibition of tumor growth and invasion by a four-kringle antagonist (HGF/NK4) for hepatocyte growth factor

Invasion of various carcinoma cells follows their interaction with stromal cells. Hepatocyte growth factor (HGF), four-kringle-containing growth factor, is a mesenchymal or stromal-derived mediator which affects the growth and the invasiveness of carcinoma cells. We now have evidence that a four-kringle-containing antagonist for HGF, HGF/NK4 inhibits invasion of tumors in vivo, as well as in vitro. HGF/NK4 competitively inhibited the binding of HGF to Met/ HGF receptors on GB-d1 human gallbladder carcinoma cells. HGF induced invasion of the cells through Matrigel basement membrane components and into collagen gels, but HGF-induced invasion was inhibited by HGF/NK4. Invasion of GB-d1 cells was induced by co-cultivation with stromal fibroblasts, which mimics tumor-stromal interaction, but it was almost completely suppressed by HGF/NK4. Likewise, invasive growth induced by HGF in collagen gels in GB-dl cells, HuCC-T1 human cholangiocarcinoma cells, and ME-180 human uterus cervical carcinoma cells was also strongly inhibited by HGF/NK4. When GB-d1 cells were implanted subcutaneously into nude mouse, tumor cells invaded muscular tissue, but the infusion of HGF/NK4 inhibited this invasion. Furthermore, HGF/NK4 increased apoptotic cell death of GB-d1 cells and inhibited tumor growth in vivo. These results indicate that HGF/ NK4 may inhibit growth and invasion of carcinoma cells, as mediated by HGF during tumor-stromal interactions. We propose that there is a unique therapeutic potential for HGF/NK4 to prevent tumor invasion and perhaps even metastasis.     

Pretruncal nonaneurysmal subarachnoid hemorrhage

BACKGROUND: Integrins are cell surface receptors which, in part, mediate the adhesion of cells to the extracellular matrix. In addition to providing a molecular "glue" essential for tissue organization and survival, integrins are dynamic signaling molecules. Integrins allow normal, nontransformed cells to sense that they are adhered to the extracellular matrix, thus providing a cell survival signal. This signal allows cells to proliferate in the presence of growth factors and in some instances prevents apoptosis. Integrins also mediate cell migration as it occurs in normal processes such as angiogenesis, wound healing, immune system function, and development. Aberrances in the expression and function of integrins contribute to many disease states including cancer. RESULTS: Focal adhesion kinase (FAK) becomes phosphorylated and activated during integrin-mediated cell adhesion. Focal adhesion kinase is a signal transducer of integrins (and certain soluble growth factors). Cells derived from FAK -/- mouse embryos exhibit reduced migration relative to wild-type cells. Cells which overexpress FAK show increased migration relative to wild-type cells. Focal adhesion kinase promotes cell survival under certain in vitro conditions. Focal adhesion kinase is overexpressed in invasive and metastatic colon, breast, thyroid, and prostate cancers. Enhanced FAK immunostaining is detected in small populations of preinvasive (carcinoma in situ) oral cancers and in large populations of cells in invasive oral cancers. CONCLUSIONS: Focal adhesion kinase is probably not a classical oncogene but may be involved in the progression of cancer to invasion and metastasis. It is hypothesized that overexpression of FAK in subpopulations of tumor cells leads to populations of cells with a high propensity toward invasion and metastasis. Focal adhesion kinase would have a dual role in this regard: Overexpression of FAK leads to (1) increased cell migration and (2) increased cell survival under anchorage-independent conditions. Further work is needed to test this model and to determine whether FAK represents a viable target for anticancer therapy.     

Inhibition of tumor cell invasion through matrigel by a peptide derived from the domain II region in urinary trypsin inhibition

Urinary trypsin inhibitor (UTI) has a multipotent inhibitory effect on proteases such as trypsin, chymotrypsin, plasmin, human leukocyte elastase, or hyaluronidase. UTI can bind easily to its receptors on various types of tumor cells (human ovarian cancer HOC-I cells, human choriocarcinoma SMT-cc1 cells, and murine Lewis lung carcinoma 3LL cells). Our results show that the UTI receptors of some tumor cells have a possible role in modulating plasmin activity on the cell surface and prevention of tumor cell invasion and metastasis (H. Kobayashi et al., J. Biol. Chem., 269; 20642-20647, 1994). UTI interacts with tumor cells as a negative modulator of the invasive cells. We investigated whether this effect may be mediated by UTI binding to the cell surface receptors. In addition, the role of peptide sequences from each UTI domain and their interaction with tumor cells were investigated. UTI derivatized with biotin or FITC was taken up by tumor cells in a dose-dependent manner. This cell association was inhibited with a monoclonal antibody D1, which specifically recognizes NH2 terminus (domain I) of UTI. The binding was inhibited by fluid phase UTI, but not HI-8, COOH terminus (domain II) of UTI, suggesting that UTI binds to cells through a site in the UTI domain I. Furthermore, we found that UTI, HI-8 and a number of peptides containing Arg-Gly-Pro-Cys-Arg-Ala-Phe-Ile promoted the inhibition of tumor cell invasion. This site corresponds to the plasmin-inhibiting domain within HI-8. The possibility that UTI binding to tumor cells might be involved in the prevention of tumor cell invasion in vitro was excluded since HI-8, lacking domain I, promotes the inhibition of tumor cell invasion with essentially the same affinity as UTI. All these data allow us to conclude that inhibition of tumor cell invasion is mediated by domain II, which possesses anti-plasmin activity.     

Soil ingestion in adults--results of a second pilot study

Numerous in vivo methodologies have documented the invasive behavior of glioma cells through normal brain parenchyma. Glioma cell locomotion has also been assessed with a number of in vitro assays including the Boyden chamber and other chemotaxis assays, colloidal gold cell tracking, analysis of migration of cells tumor cells from spheroids, confrontation cultures of glioma cells with aggregates of non-neoplastic tissue, time-lapse video microscopy, electron microscopic examination of the cytomorphologic correlates of cell motility, the radial dish assay, and quantitative enzyme immunoassay of proteins associated with invasion (e.g. laminin). Several of these techniques have been specifically modified to assess the effects of cytokines on glioma cell motility in vitro. Cytokines studied utilizing these methods include: epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), the bb dimer of platelet-derived growth factor (PDGFbb), nerve growth factor (NGF), interleukin 2 (IL-2), transforming growth factors alpha and beta 1 (TGF alpha and TGFstraat1), and tumor necrosis factor alpha (TNF alpha). This review summarizes the investigational methods used to evaluate random and directional glioma cell motility and invasion in vivo and in vitro. The roles of specific mitogens as motogens, as evaluated with these methods are then presented.     

Immunohistochemical study of MT-MMP tissue status in gastric carcinoma and correlation with survival analyzed by univariate and multivariate analysis

Matrix metalloproteinase (MMP) expression is associated with advanced-stage cancer and contributes to tumor progression, invasion, and metastasis. Membrane type matrix metalloproteinase (MT-MMP) has a potential transmembrane domain at the C terminus and activates pro-MMP-2, which is mainly produced from interstitial fibroblasts. Its expression on the membrane of invasive tumor cells results in the pericellular space degradation at cell-matrix contact sites and renders cancer cells more invasive at the migration front. To elucidate the relationship between MT-MMP expression and metastasis and prognosis in gastric cancer patients, MT-MMP expression was analyzed immunohistochemically in 127 primary tumors and results were correlated with several prognostic parameters and patient's survival. MT-MMP immunoreactivity was stained on the cell membrane of cancer cells and fibroblasts in the invasion front. MT-MMP was detected in 72 tumors (57%) (MT-MMP-positive). MT-MMP expression was closely associated with macroscopically invasive type, nodal involvement, lymphatic invasion, vessel invasion, and peritoneal dissemination. Patients with MT-MMP-positive tumor had a significantly worse prognosis than those with MT-MMP-negative tumor (p<0.001). Multivariate analysis showed MT-MMP overexpression as an independent prognostic factor in gastric cancer patients. Immunohistochemical analysis for MT-MMP may be an indicator of metastatic potential or the prognosis of gastric cancer patients.