The plasminogen-plasmin system in malignancy

Do coagulation or fibrinolysis reflect the disease condition in patients with soft tissue sarcoma?

BACKGROUND

Coagulation and fibrinolysis are distinct processes that are highly correlated. Cells control coagulation and fibrinolysis by expression of tissue factor and urokinase-type plasminogen activator receptor on their surface. Tumor cells express these proteins, adjust their microenvironment and induce tumor exacerbation. We hypothesized that the expression of plasma markers for coagulation and fibrinolysis in patients with soft tissue sarcomas (STSs) was dependent on the level of tumor malignancy. To elucidate which markers are predictive of recurrence, metastasis and prognosis, coagulation or fibrinolysis, we analyzed the correlation between plasma levels of thrombin-antithrombin III complex (TAT), soluble fibrin (SF), plasmin-α2 plasmin inhibitor complex (PIC), D-dimer (DD) and clinical parameters in patients with STSs.

METHODS

TAT, SF, PIC or DD were measured in pre-treatment blood samples from 64 patients with primary STSs and analyzed with clinicopathological parameters, and 5-year recurrence free survival (RFS), 5-year metastasis free survival (MFS) and 5-year overall survival (OS) were evaluated.

RESULTS

The metastasis group had significantly higher DD (p = 0.0394), PIC (p = 0.00532) and SF (p = 0.00249) concentrations than the group without metastasis. The group that died of disease showed significantly higher DD (p = 0.00105), PIC (p = 0.000542), SF (p = 0.000126) and TAT (p = 0.0373) than surviving patients. By dividing the patients into low and high groups, the group with high DD, PIC, SF and TAT showed significantly lower 5-year MFS and 5-year OS than the corresponding low group. Furthermore, in multivariate COX proportional hazard analysis of continuous variables for 5-year MFS, only PIC was found to be a significant factor (HR: 2.14).

CONCLUSION

Fibrinolysis was better than coagulation at reflecting the disease condition of patients with STS. Notably, PIC levels ≥ 1.1 can not only predict the risk of metastasis and poor prognosis, but also increasing PIC levels correspond to further increases in risks of metastasis and poor prognosis.

Brain-invasive meningiomas: molecular mechanisms and potential therapeutic options

Meningiomas are the most commonly diagnosed benign intracranial adult tumors. Subsets of meningiomas that present with extensive invasion into surrounding brain areas have high recurrence rates, resulting in difficulties for complete resection, substantially increased mortality of patients, and are therapeutically challenging for neurosurgeons. Exciting new data have provided insights into the understanding of the molecular machinery of invasion. Moreover, clinical trials for several novel approaches have been launched. Here, we will highlight the mechanisms which govern brain invasion and new promising therapeutic approaches for brain-invasive meningiomas, including pharmacological approaches targeting three major aspects of tumor cell invasion: extracellular matrix degradation, cell adhesion, and growth factors, as well as other innovative treatments such as immunotherapy, hormone therapy, Tumor Treating Fields, and biodegradable copolymers (wafers), impregnated chemotherapy. Those ongoing studies can offer more diversified possibilities of potential treatments for brain-invasive meningiomas, and help to increase the survival benefits for patients.

Significance of coagulation and fibrinolysis markers for benign and malignant soft tissue tumors

Background

The intimate relationship between coagulation and fibrinolysis in malignant tumors is a well-known phenomena, with the malignant phenotype enhancing coagulation and fibrinolysis. We hypothesized that soft tissue sarcoma (STS) affects the expression of coagulation and fibrinolysis markers, which could be used to distinguish STS from benign soft tissue tumors. We analyzed the correlations between plasma levels of D-dimer (DD), plasmin-α2 plasmin inhibitor complex (PIC), soluble fibrin (SF), and thrombin-antithrombin III complex (TAT) in benign soft tissue tumors and STS to elucidate whether these markers can be used to predict STS.

Methods

Plasma DD, PIC, SF and TAT levels in primary soft tissue tumors (benign 67, STS 68) were measured before biopsy or treatment. The marker levels were analyzed and compared to various clinicopathological parameters.

Results

In malignancy (STS), the average DD, PIC and SF levels were significantly higher than in benign tumors. Multivariate logistic analysis of continuous variables indicated that only PIC exhibited a significant difference (OR: 24.5, 95%CI: 3.55–170, p = 0.0012). Receiver operating characteristic curve analysis produced area under the curve values for DD: 0.691, PIC: 0.784, SF: 0.734 and TAT: 0.588. Youden’s index was used to establish thresholds of 0.37 (DD), 0.80 (PIC), 0.90 (SF) and 0.82 (TAT). Threshold values for PIC and SF indicated high specificity (0.881, 0.791) and high positive predictive value (0.818, 0.745), respectively. The highest accuracy value among the markers was observed for PIC (0.704). Significant differences in multivariate analysis of binary variables were demonstrated by categorizing low and high groups based on their threshold, PIC (≥0.80) (OR: 3.36, 95%CI: 1.19–9.43, p = 0.0212) and SF (≥0.90) (OR: 2.63, 95%CI: 1.04–6.66, p = 0.0404) .

Conclusions

Of the coagulation and fibrinolysis markers studied, increased PIC levels were related to STS and over 0.80 PIC was the most suitable for the prediction of STS, which, along with other diagnostic tools, represents a helpful subsidiary tool for the prediction of STS.

Annexin A2 (ANX A2): An emerging biomarker and potential therapeutic target for aggressive cancers

ANX A2 is an important member of annexin family of proteins expressed on surface of endothelial cells (ECs), macrophages, mononuclear cells and various types of cancer cells. It exhibits high affinity binding for calcium (Ca⁺⁺ ) and phospholipids. ANX A2 plays an important role in many biological processes such as endocytosis, exocytosis, autophagy, cell-cell communications and biochemical activation of plasminogen. On the cell surface ANX A2 organizes the assembly of plasminogen (PLG) and tissue plasminogen activator (tPA) for efficient conversion of PLG to plasmin, a serine protease. Proteolytic activity of plasmin is required for activation of inactive pro-metalloproteases (pro-MMPs) and latent growth factors for their biological actions. These activation steps are critical for degradation of extracellular matrix (ECM) and basement proteins (BM) for cancer cell invasion and metastasis. Increased expression of ANX A2 protein/gene has been correlated with invasion and metastasis in a variety of human cancers. Moreover, clinical studies have positively correlated ANX A2 protein expression with aggressive cancers and with resistance to anticancer drugs, shorter disease-free survival (DFS), and worse overall survival (OS). The mechanism(s) by which ANX A2 regulates cancer invasion and metastasis are beginning to emerge. Investigators used various technologies to target ANX A2 in preclinical model of human cancers and demonstrated exciting results. In this review article, we analyzed existing literature concurrent with our own findings and provided a critical overview of ANX A2-dependent mechanism(s) of cancer invasion and metastasis.

Cell surface protease activation during RAS transformation: Critical role of the plasminogen receptor, S100A10

The link between oncogenic RAS expression and the acquisition of the invasive phenotype has been attributed to alterations in cellular activities that control degradation of the extracellular matrix. Oncogenic RAS-mediated upregulation of matrix metalloproteinase 2 (MMP-2), MMP-9 and urokinase-type plasminogen activator (uPA) is critical for invasion through the basement membrane and extracellular matrix. The uPA converts cell surface-bound plasminogen to plasmin, a process that is regulated by the binding of plasminogen to specific receptors on the cell surface, however, the identity of the plasminogen receptors that function in this capacity is unclear. We have observed that transformation of cancer cells with oncogenic forms of RAS increases plasmin proteolytic activity by 2- to 4-fold concomitant with a 3-fold increase in cell invasion. Plasminogen receptor profiling revealed RAS-dependent increases in both S100A10 and cytokeratin 8. Oncogenic RAS expression increased S100A10 gene expression which resulted in an increase in S100A10 protein levels. Analysis with the RAS effector-loop mutants that interact specifically with Raf, Ral GDS pathways highlighted the importance of the RalGDS pathways in the regulation of S100A10 gene expression. Depletion of S100A10 from RAS-transformed cells resulted in a loss of both cellular plasmin generation and invasiveness. These results strongly suggest that increases in cell surface levels of S100A10, by oncogenic RAS, plays a critical role in RAS-stimulated plasmin generation, and subsequently, in the invasiveness of oncogenic RAS expressing cancer cells.

Amorphous protein aggregates stimulate plasminogen activation, leading to release of cytotoxic fragments that are clients for extracellular chaperones

The misfolding of proteins and their accumulation in extracellular tissue compartments as insoluble amyloid or amorphous protein aggregates are a hallmark feature of many debilitating protein deposition diseases such as Alzheimer's disease, prion diseases, and type II diabetes. The plasminogen activation system is best known as an extracellular fibrinolytic system but was previously reported to also be capable of degrading amyloid fibrils. Here we show that amorphous protein aggregates interact with tissue-type plasminogen activator and plasminogen, via an exposed lysine-dependent mechanism, to efficiently generate plasmin. The insoluble aggregate-bound plasmin is shielded from inhibition by α₂-antiplasmin and degrades amorphous protein aggregates to release smaller, soluble but relatively hydrophobic fragments of protein (plasmin-generated protein fragments (PGPFs)) that are cytotoxic. In vitro, both endothelial and microglial cells bound and internalized PGPFs before trafficking them to lysosomes. Clusterin and α₂-macroglobulin bound to PGPFs to significantly ameliorate their toxicity. On the basis of these findings, we hypothesize that, as part of the in vivo extracellular proteostasis system, the plasminogen activation system may work synergistically with extracellular chaperones to safely clear large and otherwise pathological protein aggregates from the body.

Tamoxifen-Induced Changes in the Plasma Fibrinolytic Factors in Menopausal Women with Breast Cancer

There is evidence that tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), and the plasminogen activator inhibitors 1 and 2 (PAI-1, PAI-2), are involved in the invasion and metastasis of breast tumors. Menopausal controls and menopausal women with breast cancer, who were taking tamoxifen, 10 mg b.i.d., had plasma antigenic levels of tPA, uPA, PAI-1, and PAI-2 determined by enzyme-linked immunosorbent assay (ELISA). In addition, five women being placed on this tamoxifen regimen also had these same determinations made before and after 6 months. Significant increases were observed for tPA, uPA, and PAI-1 in the 26 tamoxifen-treated patients. The percent increase in tPA and uPA combined were greater than that of PAI-1. Nonsignificant increases were also seen in the five women evaluated before and after initiation of treatment. Linear correlations were seen for tPA and PAI-1 over time length of exposure to tamoxifen. Ratios of tPA/PAI- 1 and UPA/PAI-1 were not significantly different, but were correlated and linear. From these data, it appears that tamoxifen increases the fibrinolytic factors in these patients and that this was not proportional as the ratios of the factors were not different after treatment. The increase in activators was greater than inhibitors, which could be detrimental in terms of the potential for invasion and metastasis of the tumor cell. As a negative correlation was seen for tPA over time while PAI- was positively correlated, this may help explain why some patients taking tamoxifen are at risk for thromboembolytic events. Key Words: TPA—uPA—PAI-1—PAI-2—Tamoxifen—Breast cancer.

A novel uPAg-KPI fusion protein inhibits the growth and invasion of human ovarian cancer cells in vitro

Urokinase-type plasminogen activator (uPA) acts by breaking down the basement membrane and is involved in cell proliferation, migration and invasion. These actions are mediated by binding to the uPA receptor (uPAR) via its growth factor domain (GFD). The present study evaluated the effects of uPAg-KPI, a fusion protein of uPA-GFD and a kunitz protease inhibitor (KPI) domain that is present in the amyloid β-protein precursor. Using SKOV-3 cells, an ovarian cancer cell line, we examined cell viability, migration, invasion and also protein expression. Furthermore, we examined wound healing, and migration and invasion using a Transwell assay. Our data showed that uPAg-KPI treatment reduced the viability of ovarian cancer SKOV-3 cells in both a concentration and time-dependent manner by arresting tumor cells at G1/G0 phase of the cell cycle. The IC₅₀ of uPAg-KPI was 0.5 µg/µl after 48 h treatment. At this concentration, uPAg-KPI also inhibited tumor cell colony formation, wound closure, as well as cell migration and invasion capacity. At the protein level, western blot analysis demonstrated that uPAg-KPI exerted no significant effect on the expression of total extracellular signal-regulated kinase (ERK)1/ERK2 and AKT, whereas it suppressed levels of phosphorylated ERK1/ERK2 and AKT. Thus, we suggest that this novel uPAg-KPI fusion protein reduced cell viability, colony formation, wound healing and the invasive ability of human ovarian cancer SKOV-3 cells in vitro by regulating ERK and AKT signaling. Further studies using other cell lines will confirm these findings.

Host protein C inhibitor inhibits tumor growth, but promotes tumor metastasis, which is closely correlated with hypercoagulability

INTRODUCTION

Protein C inhibitor (PCI), a member of the serine protease inhibitor family, is expressed in various human tissues, including liver and kidneys. In the plasma, PCI physiologically inhibits an anticoagulant serine protease, activated protein C (APC). PCI expressed by cancer cells suppresses tumor invasion by inhibiting urokinase-type plasminogen activator, and inhibits tumor growth and metastasis, which are independent of its protease-inhibitory activity. In the present study, we clarified the effects of host PCI on growth and metastasis of B16 melanoma (B16) cells by comparing between wild-type mice and mice transgenic for human PCI gene (hPCI-TG), which have a tissue distribution of PCI similar to that observed in humans.

MATERIALS AND METHODS

Growth of intracutaneously-injected B16 cells was evaluated by measuring the tumor volume, and metastatic behavior of intravenously-injected B16 cells by counting the number of metastatic lung nodules.

RESULTS

Growth of intracutaneously injected B16 cells was significantly faster in wild-type mice than in hPCI-TG mice; however, hPCI-TG mice developed more metastatic nodules of B16 cells in the lungs. Immunohistochemical analysis using anti-mouse fibrinogen antibody revealed more fibrin deposition in the lung in hPCI-TG mice than in wild-type mice. Furthermore, the more invasive behavior observed in hPCI-TG mice was reduced by rabbit anti-human PCI IgG, APC, or soluble TM administration for 3 consecutive days including the day that B16 cells were injected.

CONCLUSIONS

Our results suggest that like PCI expressed in tumor cells, host PCI also inhibits tumor growth, but host PCI promotes tumor metastasis via its procoagulant properties.

Components of the Plasminogen-Plasmin System as Biologic Markers for Cancer

Members of the plasminogen-plasmin (PP) system participate in many physiologic functions. In particular, uPA, its receptor (uPAR) and its inhibitor PAI-1 play an important role in cell migration, cell proliferation and tissue remodeling. Through a number of interactions, these components of the PP system are also involved in the pathogenesis of many diseases. In cancer, they modulate the essential processes of tumor development, growth, invasion and metastasis as well as angiogenesis and fibrosis. Thus, quantification of uPA, uPAR and PAI-1 in tumors and, in some cases in the circulating blood, became of potential value in the prognostication of many types of cancer. These include cancer of the breast, stomach, colon and rectum, esophagus, pancreas, glioma, lung, kidney, prostate, uterine cervix, ovary, liver and bone. Published data are reviewed in this chapter. Clinical validation of the prognostic value has also been made, particularly in cancer of the breast. Inclusion of these biomarkers in the risk assessment of cancer patients is now considered in the risk-adapted management in carcinoma of the breast. Factors limiting its broader use are discussed with suggestions how these can be overcome. Hopefully the use of these biomarkers will be applied to other types of cancer in the near future.

Cancer and venous thromboembolic disease: from molecular mechanisms to clinical management

Venous thromboembolism (vte) represents a major challenge in the management of patients with cancer. The malignant phenotype is associated with derangements in the coagulation cascade that can manifest as thrombosis, hemorrhage, or disseminated intravascular coagulation. The risk of vte is increased by a factor of approximately 6 in patients with cancer compared with non-cancer patients, and cancer patients account for approximately 20% of all newly diagnosed cases of vte. Postmortem studies have demonstrated rates of vte in patients with cancer to be as high as 50%. Despite that prevalence, vte prophylaxis is underused in hospitalized patients with cancer. Studies have demonstrated that hospitalized patients with cancer are less likely than their non-cancer counterparts to receive vte prophylaxis. Consensus guidelines address the aforementioned issues and emerging concepts in the area, including the use of risk-assessment models, biomarkers to identify patients at highest risk of vte, and use of anticoagulants as anticancer therapy. Despite those guidelines, a gulf exists between current recommendations and clinical practice; greater efforts are thus required to ensure effective implementation of strategies to reduce the incidence of vte in patients with cancer.

Common acquired causes of thrombosis in children

Compared to adults, venous thromboembolism in the pediatric population is a rare event. Cancer, cardiac disease, antiphospholipid antibodies, and indwelling catheters are established risk factors for thromboembolism in children. We examined the literature related to thrombophilia in children, childhood cancer and thrombosis, cardiac disease and thrombosis, and antiphospholipid antibody syndrome in children. Citations in identified articles yielded additional articles for review. We found that studies of acquired thrombophilia in children are limited. Current treatment for thromboembolism in children is based on adult data therefore optimal treatment in this population remains unclear.

Clinical significance of annexin II expression in human non-small cell lung cancer

The aim of the present study is to explore the role of annexin II in the development and progression of human non-small cell lung cancer (NSCLC). Real-time quantitative reverse transcription-polymerase chain reaction was conducted to detect annexin II mRNA expression. Annexin II protein expression was also determined by western blot. In addition, annexin II expression was analyzed by immunohistochemistry in 137 clinicopathologically characterized NSCLC cases. The correlation of annexin II expression with patients' survival rate was assessed by Kaplan-Meier analysis and Cox regression. Our results showed that the expression levels of annexin II mRNA and protein in NSCLC tissues were significantly higher than those in non-cancerous tissues. Immunohistochemistry analysis showed that annexin II expression was significantly correlated with tumor diameter, pathological grade, pT status, pN status, and pleural invasion. The results of the Kaplan-Meier analysis indicated that a high expression level of annexin II resulted in a significantly poor prognosis of NSCLC patients. Multi-variate Cox regression analysis revealed that annexin II expression level was an independent prognostic parameter for the overall survival rate of NSCLC patients. In conclusion, these results suggested that annexin II up-regulation was associated with poor prognosis in NSCLC; therefore, it might act as a prognostic marker and a new potential target for NSCLC treatment.

The biochemistry and regulation of S100A10: a multifunctional plasminogen receptor involved in oncogenesis

The plasminogen receptors mediate the production and localization to the cell surface of the broad spectrum proteinase, plasmin. S100A10 is a key regulator of cellular plasmin production and may account for as much as 50% of cellular plasmin generation. In parallel to plasminogen, the plasminogen-binding site on S100A10 is highly conserved from mammals to fish. S100A10 is constitutively expressed in many cells and is also induced by many diverse factors and physiological stimuli including dexamethasone, epidermal growth factor, transforming growth factor-α, interferon-γ, nerve growth factor, keratinocyte growth factor, retinoic acid, and thrombin. Therefore, S100A10 is utilized by cells to regulate plasmin proteolytic activity in response to a wide diversity of physiological stimuli. The expression of the oncogenes, PML-RARα and KRas, also stimulates the levels of S100A10, suggesting a role for S100A10 in pathophysiological processes such as in the oncogenic-mediated increases in plasmin production. The S100A10-null mouse model system has established the critical role that S100A10 plays as a regulator of fibrinolysis and oncogenesis. S100A10 plays two major roles in oncogenesis, first as a regulator of cancer cell invasion and metastasis and secondly as a regulator of the recruitment of tumor-associated cells, such as macrophages, to the tumor site.

Upregulated expression of annexin II is a prognostic marker for patients with gastric cancer

Background

The role of annexin II in the development and progression of gastric cancer was explored.

Methods

Real-time PCR was conducted to detect annexin II and S100A6 mRNA expression. Protein expressions of annexin II and S100A6 were also examined by immunohistochemistry in 436 clinicopathologically characterized gastric cancer cases.

Results

The expression of annexin II and S100A6 mRNA differ significantly among gastric tumor tissue and matched non-cancerous gastric mucosa. Protein levels of annexin II and S100A6 were up-regulated in gastric cancer compared with adjacent non-cancerous tissues. High expression of annexin II correlated with age, location of tumor, size of tumor, differentiation, histological type, depth of invasion, vessel invasion, lymph node metastasis, distant metastasis and Tumor, Node, Metastasis (TNM) stage, and also with expression of S100A6. Further multivariate analysis suggested that expression of annexin II and S100A6 were independent prognostic indicators for gastric cancer.

Cumulative five-year survival rates of patients with high expression of both annexin II and S100A6 was significantly lower than those with low expression of both.

Conclusion

Expression of annexin II in gastric cancer was significantly associated with depth of invasion, lymph node metastasis and distant metastasis, TNM stage, high S100A6 expression, and poor prognosis. Annexin II and S100A6 proteins could be useful prognostic marker to predict tumor progression and prognosis in gastric cancer.

The interaction of the second Kunitz-type domain (KD2) of TFPI-2 with a novel interaction partner, prosaposin, mediates the inhibition of the invasion and migration of human fibrosarcoma cells

TFPI-2 (tissue factor pathway inhibitor-2) has recently been recognized as a new tumour suppressor gene. Low expression of this protein in several types of cancers allows for enhanced tumour growth, invasion and metastasis. To investigate the molecular mechanism responsible for the tumour-suppressor effects of TFPI-2, we performed yeast two-hybrid analysis and identified PSAP (prosaposin) as a TFPI-2-interacting partner. This interaction was confirmed by co-immunoprecipitation and immunofluorescence. The region of TFPI-2 that interacts with PSAP is located in the KD2 (Kunitz-type domain 2). Further study showed that PSAP does not affect the function of TFPI-2 as a serine proteinase inhibitor, but that TFPI-2 could inhibit the invasion-promoting effects of PSAP in human HT1080 fibrosarcoma cells. The results of the present study revealed that TFPI-2 interacts with PSAP, which may play an important role in the physiology and pathology of diseases such as cancer.

Natural and engineered plasmin inhibitors: applications and design strategies

The serine protease plasmin is ubiquitously expressed throughout the human body in the form of the zymogen plasminogen. Conversion to active plasmin occurs through enzymatic cleavage by plasminogen activators. The plasminogen activator/plasmin system has a well-established function in the removal of intravascular fibrin deposition through fibrinolysis and the inhibition of plasmin activity; this has found widespread clinical use in reducing perioperative bleeding. Increasing evidence also suggests diverse, although currently less defined, roles for plasmin in a number of physiological and pathological processes relating to extracellular matrix degradation, cell migration and tissue remodelling. In particular, dysregulation of plasmin has been linked to cancer invasion/metastasis and various chronic inflammatory conditions; this has prompted efforts to develop inhibitors of this protease. Although a number of plasmin inhibitors exist, they commonly suffer from poor potency and/or specificity of inhibition that either results in reduced efficacy or prevents clinical use. Consequently, there is a need for further development of high-affinity plasmin inhibitors that maintain selectivity over other serine proteases. This review summarises clearly defined and potential applications for plasmin inhibition. The properties of naturally occurring and engineered plasmin inhibitors are discussed in the context of current knowledge regarding plasmin structure, specificity and function. This includes design strategies to obtain the potency and specificity of inhibition in addition to controlled temporal and spatial distribution tailored for the intended use.

The role of the annexin A2 heterotetramer in vascular fibrinolysis

The vascular endothelial cells line the inner surface of blood vessels and function to maintain blood fluidity by producing the protease plasmin that removes blood clots from the vasculature, a process called fibrinolysis. Plasminogen receptors play a central role in the regulation of plasmin activity. The protein complex annexin A2 heterotetramer (AIIt) is an important plasminogen receptor at the surface of the endothelial cell. AIIt is composed of 2 molecules of annexin A2 (ANXA2) bound together by a dimer of the protein S100A10. Recent work performed by our laboratory allowed us to clarify the specific roles played by ANXA2 and S100A10 subunits within the AIIt complex, which has been the subject of debate for many years. The ANXA2 subunit of AIIt functions to stabilize and anchor S100A10 to the plasma membrane, whereas the S100A10 subunit initiates the fibrinolytic cascade by colocalizing with the urokinase type plasminogen activator and receptor complex and also providing a common binding site for both tissue-type plasminogen activator and plasminogen via its C-terminal lysine residue. The AIIt mediated colocalization of the plasminogen activators with plasminogen results in the rapid and localized generation of plasmin to the endothelial cell surface, thereby regulating fibrinolysis.

The role of annexin A2 in tumorigenesis and cancer progression

Annexin A2 is a calcium-dependent, phospholipid-binding protein found on various cell types. It is up-regulated in various tumor types and plays multiple roles in regulating cellular functions, including angiogenesis, proliferation, apoptosis, cell migration, invasion and adhesion. Annexin A2 binds with plasminogen and tissue plasminogen activator on the cell surface, which leads to the conversion of plasminogen to plasmin. Plasmin is a serine protease which plays a key role in the activation of metalloproteinases and degradation of extracellular matrix components essential for metastatic progression. We have recently found that both annexin A2 and plasmin are increased in conditioned media of co cultured ovarian cancer and peritoneal cells. Our studies suggest that annexin A2 is part of a tumor-host signal pathway between ovarian cancer and peritoneal cells which promotes ovarian cancer metastasis. Accumulating evidence suggest that interactions between annexin A2 and its binding proteins play an important role in the tumor microenvironment and act together to enhance cancer metastasis. This article reviews the current knowledge on the biological role of annexin A2 and its binding proteins in solid malignancies including ovarian cancer.

Oral administration of benzyl-isothiocyanate inhibits solid tumor growth and lung metastasis of 4T1 murine mammary carcinoma cells in BALB/c mice

Benzyl-isothiocyanate (BITC) is a hydrolysis product of glucotropaeolin, a compound found in cruciferous vegetables, and has also been shown to have anti-tumor properties. To evaluate the effects of BITC administration on the tumor growth and metastasis of breast cancer, 4T1 murine mammary carcinoma cells were injected into the inguinal mammary fat pads of syngeneic female BALB/c mice. One day later, the mice were subjected to gavage for 4 weeks with BITC (0, 5, or 10 mg/kg body weight/day). Oral BITC treatment induced a significant reduction in the growth of solid tumors. BITC reduced hemoglobin contents and CD31 and vascular endothelial growth factor (VEGF) expression in the tumors, as well as circulating levels of VEGF. Reduced expressions of proliferating cell nuclear antigen and cyclin-dependent kinase 4 were noted in the tumors of BITC-treated mice. BITC markedly increased the numbers of apoptotic cells with increased Bax expression, cleaved caspase-3, and PARP levels, but reduced Bcl-2 expression in tumor tissues. In addition, BITC was shown to reduce the numbers of pulmonary tumor nodules and the total pulmonary metastatic volume. BITC induced a significant reduction in the levels of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, and urokinase-type plasminogen activator in the sera and lungs of 4T1 cell-injected mice. However, the concentrations of TIMP-2 and plasminogen activator inhibitor-1 were increased in the sera and lungs of BITC-treated mice. The results of this study indicate that BITC has potential as a preventive agent for metastatic breast cancer.

Phenethyl isothiocyanate inhibited tumor migration and invasion via suppressing multiple signal transduction pathways in human colon cancer HT29 cells

Phenethyl isothiocyanate (PEITC), one of the major compounds from dietary cruciferous vegetables, has been found to have antitumor properties and therefore could generate special interest for the development of chemopreventive and/or chemotherapeutic agent for human cancers. In the primary studies, we found that PEITC induced cytotoxic effect (decreased the percentage of viable cells) in human colon cancer HT29 cells. Here, in this study, we are the first to report the antimetastatic effect of PEITC in HT29 human colon cancer cells. The results show that PEITC exhibited an inhibitory effect on the abilities of adhesion, migration, and invasion by Boyden chamber assay. Western blotting examination indicated that PEITC exerted an inhibitory effect on the SOS-1, PKC, ERK1/2 and Rho A for causing the inhibitions of MMP-2 and -9 then followed by the inhibition of invasion and migration of HT29 cells in vitro. PEITC also affected Ras, FAK, PI3K or inhibited GRB2, NF-κB, iNOS and COX-2 for causing the inhibition of cell proliferation in HT29 cells. Real-time PCR also showed that PEITC inhibited the gene expressions of MMP-2, -7, -9, FAK and Rho A after PEITC treatment for 48 h in HT29 cells. PEITC also inhibited the activities of AKT, ERK, JNK and PKC. Our results provide a new insight into the mechanisms and functions of PEITC which inhibit migration and invasion of HT29 human colon cancer cells. These results suggest that molecular targeting of NF-κB led to the inhibition of MMP-2, -7, and -9 and it might be a useful strategy for the inhibition of migration and invasion on human colon cancer.

Gypenosides inhibits migration and invasion of human oral cancer SAS cells through the inhibition of matrix metalloproteinase-2 -9 and urokinase-plasminogen by ERK1/2 and NF-kappa B signaling pathways

Gypenosides (Gyp), found in Gynostemma pentaphyllum Makino, has been used as a folk medicine in the Chinese population for centuries and is known to have diverse pharmacologic effects, including anti-proliferative and anti-cancer actions. However, the effects of Gyp on prevention from invasion and migration of oral cancer cells are still unsatisfactory. The purpose of this study was to investigate effects of Gyp treatment on migration and invasion of SAS human oral cancer cells. SAS cells were cultured in the presence of 90 and 180 μg/mL Gyp for 24 and 48 hours. Gyp induced cytotoxic effects and inhibited SAS cells migration and invasion in dose- and time-dependent response. Wound-healing assay and boyden chamber assay were carried out to investigate Gyp-inhibited migration and invasion of SAS cells. Gyp decreased the abundance of several proteins, including nuclear factor-kappa B (NF-κB), cyclooxygenase-2 (COX-2), extracellular signal-regulated kinase 1/2 (ERK1/ 2), matrix metalloproteinase-9, -2 (MMP-9, -2), sevenless homolog (SOS), Ras, urokinase-type plasminogen activator (uPA), focal adhesion kinase (FAK) and RAC-alpha serine/threonine-protein kinase (Akt), in a time-dependent manner. In addition, Gyp decreased mRNA levels of MMP-2, MMP-7, MMP-9 but did not affect FAK and Rho A mRNA levels in SAS cells. These results provide evidences for the role of Gyp as a potent anti-metastatic agent, which can markedly inhibit the metastatic and invasive capacity of oral cancer cells. The inhibition of NF-κB and MMP-2, -7 and -9 signaling may be one of the mechanisms that is present in Gyp-inhibited cancer cell invasion and migration.

Benzyl isothiocyanate (BITC) inhibits migration and invasion of human gastric cancer AGS cells via suppressing ERK signal pathways

Metastasis suppressors and associated other regulators of cell motility play a critical initial role in tumor invasion and metastases. Benzyl isothiocyanate (BITC) is a hydrolysis compound of glucotropaeolin in dietary cruciferous vegetables. BITC has been found to exhibit prevention of cancers in laboratory animals and might also be chemoprotective in humans. Here, the purpose of this study was to investigate the effects of BITC on cell proliferation, migration, invasion and mitogen-activated protein kinase (MAPK) pathways of AGS human gastric cancer cells. Wound healing and Boyden chamber (migration and invasion) assays demonstrated that BITC exhibited an inhibitory effect on the abilities of migration and invasion in AGS cancer cells. BITC suppressed cell migration and invasion of AGS cells in a dose-dependent manner. Results from Western blotting indicated that BITC exerted an inhibitory effect on the ERK1/2, Ras, GRB2, Rho A, iNOS, COX-2 for causing the inhibitions of MMP-2, -7 and -9 then followed by the inhibitions of invasion and migration of AGS cells in vitro. BITC also promoted MKK7, MEKK3, c-jun, JNK1/2, VEGF, Sos1, phosphoinositide 3-kinase (PI3K), PKC, nuclear factor-kappaB (NF-κB) p65 in AGS cells. Results from real-time polymerized chain reaction (PCR) showed that BITC inhibited the gene expressions of MMP-2,-7 -9, FAK, ROCK1 and RhoA after BITC treatment for 24 and 48 hours in AGS cells. Taken together, the finding may provide new mechanisms and functions of BITC, which inhibit migration and invasion of human gastric cancer AGS cells.

Benzyl isothiocyanate (BITC) inhibits migration and invasion of human colon cancer HT29 cells by inhibiting matrix metalloproteinase-2/-9 and urokinase plasminogen (uPA) through PKC and MAPK signaling pathway

Benzyl isothiocyanate (BITC), a component of dietary cruciferous vegetables, has antioxidant and anticancer properties. In this study, we show for the first time the antimetastatic effects of BITC in human colon cancer HT29 cells. BITC had an inhibitory effect on cell migration and invasion. Protein levels of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and urokinase-plasminogen activator (u-PA) were reduced by BITC in a concentration-dependent manner. BITC also exerted an inhibitory effect on phosphorylation of c-Jun N-terminal kinase 1 and 2 (JNK1/2), extracellular signal-regulated kinases 1 and 2 (ERK1/2), phosphatidylinositol 3-kinase (PI3K) and protein kinase C (PKC) that are upstream of nuclear factor kappa B (NF-kappaB). BITC inhibited DNA binding activity of NF-kappaB. Moreover, BITC decreased the levels of c-Fos, c-Jun, Ras, FAK, PI3K and GRB2 in HT29 cells. Reductions in the enzyme activity, protein and mRNA (mRNA) levels of MMP-2 were observed in BITC-treated HT29 cells. BITC also inhibited mRNA levels of MMP-2, -7, and -9 in HT29 cells. Results from zymography showed that BITC treatment decreased MMP-2 expression in a concentration-dependent manner. BITC inhibited PKCdelta activity in HT29 cells. Furthermore, inhibitors specific for JNK (SP600125) reduced expression of MMP-2, MMP-9, and u-PA. These results demonstrated that BITC could alter HT29 cell metastasis by reduction of MMP-2, MMP-9, and u-PA expression through the suppression of a PKC, MAPK signaling pathway and inhibition of NF-kappaB levels. These findings suggest that BITC has potential as an antimetastatic agent.

Erythropoiesis stimulating agents, thrombosis and cancer

Venous thromboembolism (VTE) is common in cancer and is associated with both morbidity and mortality. Erythropoiesis stimulating agents (ESAs) were originally developed to correct anemia. Recent trials in cancer patients however, raise concerns over both increased VTE rates and the possibility of worse tumour outcomes and increased mortality with ESA use. The most common reason offered for explaining the possible negative impact of ESAs on cancer outcomes has been the stimulation of erythropoietin receptors on tumour cells. Despite an extensive literature, it is unlikely that most practicing appreciate the intricate relationship and interaction between the coagulation pathways, angiogenesis and tumour progression and ESA effects. This paper will review these connections and interactions and examine the hypothesis that other mechanisms may underlie the possible negative impact of ESAs on cancer outcomes.

Impact of venous thromboembolism and anticoagulation on cancer and cancer survival

Changes in the hemostatic system and chronic hemostatic activation are frequently observed in patients with cancer, even in the absence of venous thromboembolism (VTE). VTE is a leading cause of death among patients with cancer and contributes to long-term mortality in patients with early as well as advanced-stage cancer. Mounting evidence suggests that components of the clotting cascade and associated vascular factors play an integral part in tumor progression, invasion, angiogenesis, and metastasis formation. Furthermore, there are intriguing in vitro and animal findings that anticoagulants, in particular the low molecular weight heparins (LMWHs), exert an antineoplastic effect through multiple mechanisms, including interference with tumor cell adhesion, invasion, metastasis formation, angiogenesis, and the immune system. Several relatively small randomized controlled clinical trials of anticoagulation as cancer therapy in patients without a VTE diagnosis have been completed. These comprise studies with LMWH, unfractionated heparin, and vitamin K antagonists, with overall encouraging but nonconclusive results and some limitations. Meta-analyses performed for the American Society of Clinical Oncology VTE Guidelines Committee and the Cochrane Collaboration suggest overall favorable effects of anticoagulation on survival of patients with cancer, mainly with LMWH. However, definitive clinical trials have been elusive and questions remain regarding the importance of tumor type and stage on treatment efficacy, the impact of fatal thromboembolic events, optimal anticoagulation therapy, and safety with differing chemotherapy regimens. Although the LMWHs and related agents hold promise for improving outcomes in patients with cancer, additional studies of their efficacy and safety in this setting are needed.

Inhibition of cell proliferation and invasion in a human colon cancer cell line by 5-aminosalicylic acid

BACKGROUND

5-Aminosalicylic acid lacks the well-known side effects associated with the long-term use of non-steroidal anti-inflammatory drugs. We investigated anti-carcinogenic mechanisms of 5-aminosalicylic acid on a colon cancer cell line.

METHODS

MTT analysis was performed for various colon cancer cell lines. The expression of NF-kappaB and metalloproteinases was examined in either HT-29 cells treated with IL-1beta and/or 5-aminosalicylic acid. Matrigel assay was used to evaluate invasive potential of HT-29 cells. Analysis of a cDNA microarray containing 8700 genes was performed to identify the alteration of gene expression in response to treatment to 5-aminosalicylic acid.

RESULTS

The use of MTT analysis showed that 5-aminosalicylic acid suppressed the growth of HT-29 cells. The activity of NF-kappaB was also decreased by combined-treatment with IL-1beta and 5-aminosalicylic acid. The use of an ELISA and zymography demonstrated that MMP-2 and MMP-9 enzyme activity were decreased in HT-29 cells by treatment with various concentration of 5-aminosalicylic acid. A matrigel analysis demonstrated that 5-aminosalicylic acid treatment on HT-29 significantly inhibited the invasiveness of the cells. In cDNA microarray, 163 genes following 5-aminosalicylic acid exposure showed altered expression.

CONCLUSIONS

This study indicated that 5-aminosalicylic acid suppresses the growth of human colon cancer cells and is able to inhibit MMPs expression via NF-kappaB mediated cell signals and invasiveness.

The role of plasminogen-plasmin system in cancer

Components of the plasminogen-plasmin system participate in a wide variety of physiologic and pathologic processes, including tumor growth, invasion and metastasis, through their effect on angiogenesis and cell migration. These components are found in most tumors and their expression not only signifies their function but also carries a prognostic value. Their expression is in turn modulated by cytokines and growth factors, many of which are up-regulated in cancer. Though both tPA and uPA are expressed in tumor cells, uPA with its receptor (uPAR) is mostly involved in cellular functions, while tPA with its receptor Annexin II on endothelial surface, regulates intravascular fibrin deposition. Among the inhibitors of fibrinolysis, PAI-1 is a major player in the pathogenesis of many vascular diseases as well as in cancer. Therapeutic interventions, either using plasminogen activators or experimental inhibitor agents against PAI-1, have shown encouraging results in experimental tumors but not been verified clinically.

Abnormal expression of TIMP-2, SOD, vimentin and PAI proteins in cloned bovine placentae

Cloned mammals suffer from high rates of placental abnormality and foetal loss during pregnancy. We previously used 2-D gel electrophoresis and mass spectrometry for global proteomic analysis of cloned and normal bovine placentae to identify differential protein expression patterns. Here, we used Western blot analysis to confirm the expression levels of several pregnancy-related proteins putatively identified as being differentially expressed in somatic cell nuclear transfer (SCNT) vs normal bovine placentae. The expression levels of tissue inhibitor of metalloproteinase-2 (TIMP-2), its downstream protein, matrix metalloproteinase-2 (MMP-2), superoxide dismutase (SOD), vimentin and plasminogen activator inhibitor-1 (PAI) were analysed in the placentae of SCNT cloned Korean native cattle that died immediately after birth and in normal placentae obtained by AI. Our results revealed that TIMP-2 and SOD were up-regulated in SCNT placenta compared with normal placenta, whereas MMP-2 levels were comparable in cloned and normal placentae, and vimentin and PAI were significantly down-regulated in SCNT compared with normal placentae. Our results suggest that key proteins of placental development are abnormally expressed in SCNT cloned bovine placentae, probably resulting in abnormal placental function and clonal mortality.

Isoliquiritigenin inhibits migration and invasion of prostate cancer cells: possible mediation by decreased JNK/AP-1 signaling

Isoliquiritigenin (ISL, 4,2',4'-trihydroxychalcone), which is found in licorice, shallot and bean sprouts, is a potent antioxidant with anti-inflammatory and anti-carcinogenic effects. The purpose of this study was to investigate the effects of ISL treatment on the migration, invasion and adhesion characteristics of DU145 human prostate cancer cells. DU145 cells were cultured in the presence of 0-20 micromol/L ISL with or without 10 microg/L epidermal growth factor (EGF). ISL inhibited basal and EGF-induced cell migration, invasion and adhesion dose dependently. ISL decreased EGF-induced secretion of urokinase-type plasminogen activator (uPA), matrix metalloproteinase (MMP)-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), and vascular endothelial growth factor (VEGF), but increased TIMP-2 secretion in a concentration-dependent manner. In addition, ISL decreased the protein levels of integrin-alpha2, intercellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM), and mRNA levels of uPA, MMP-9, VEGF, ICAM and integrin-alpha2. Furthermore, basal and EGF-induced activator protein (AP)-1 binding activity and phosphorylation of Jun N-terminal kinase (JNK), c-Jun and Akt were decreased after ISL treatment. However, phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and p38 mitogen-activated protein kinase was not altered. The JNK inhibitor SP600125 inhibited basal and EGF-induced secretion of uPA, VEGF, MMP-9 and TIMP-1, as well as AP-1 DNA binding activity and cell migration. These results provide evidence for the role of ISL as a potent antimetastatic agent, which can markedly inhibit the metastatic and invasive capacity of prostate cancer cells. The inhibition of JNK/AP-1 signaling may be one of the mechanisms by which ISL inhibits cancer cell invasion and migration.

Interleukin-10 may participate in regulating trophoblast invasion in human placentae throughout gestation

PROBLEM

A successful human pregnancy requires cytotrophoblasts from the fetal portion of the placenta to adopt tumor-like properties. But unlike tumor metastasis, cytotrophoblast invasion is highly regulated both spatially and temporally. The mechanisms that regulate human trophoblast invasion are understood poorly.

METHOD OF STUDY

With a view to obtain some findings on the mechanisms that regulate human trophoblast invasion, we applied the semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) method to compare the expression of invasion-associated genes in cytotrophoblasts isolated from first- and third-trimester placental tissues.

RESULTS

In trophoblast cells of first-trimester pregnancy, the mRNA contents of matrix metalloproteinase (MMP)-9 and urokinase-type plasminogen activator (uPA) were higher than that in the third-trimester cytotrophoblasts, while no difference of MMP-2 mRNA expression level was found between trophoblastic cells of different gestational ages. The expression level of plasminogen activator inhibitors-1 mRNA in first-trimester cytotrophoblasts was shown to be much lower than that in trophoblast cells prepared from third-trimester placental tissues. Furthermore, expression of both tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in cytotrophoblasts were significantly up-regulated in third-trimester when compared with the first-trimester of pregnancy. To further investigate the factors that caused the change of invasion-associated genes expression in trophoblast cells, we found that interleukin-10 (IL-10) could decrease the content of MMP-9 mRNA in cytotrophoblasts of first-trimester gestation, and the magnitude of suppression increased with increasing IL-10 concentration.

CONCLUSION

The gradually reduced trophoblast invasion with gestational weeks might be on account of the change of proteolytic enzymes/activator/inhibitor genes expression. IL-10 could be one of the factors participating in the regulation of trophoblast invasion during gestational process.

(-)-Epigallocatechin-3-gallate (EGCG) inhibits HGF-induced invasion and metastasis in hypopharyngeal carcinoma cells

Hepatocyte growth factor (HGF) has recently attracted a considerable amount of attention as a stromal-derived mediator in tumor-stromal interactions, particularly because of its close involvement in cancer invasion and metastasis, and (-)-epigallocatechin-3-gallate (EGCG) can modulate the cell signaling associated with angiogenesis, metastasis, and migration of cancer cells. In the present study, we have investigated the effects of HGF on invasion and metastasis of hypopharyngeal carcinoma cells and the effect of EGCG on blocking HGF-induced invasion and metastasis in these cells. We found that HGF promoted the autophosphorylation of c-Met, HGF receptor, and that HGF-induced proliferation, colony dispersion, migration and invasion of tumors. We also observed that HGF enhanced the activity of matrix metalloproteinase (MMP)-9 and urokinase-type plasminogen activator (uPA) in hypopharyngeal carcinoma cells. In addition, HGF-induced the activation of Akt and Erk pathway as a downstreaming pathway of invasion. On the other hand, EGCG at physiologically relevant concentration (1 microM) suppressed HGF-induced tumor motility and MMP-9 and uPA activities, and the suppression of Akt and Erk pathway by EGCG was one of the downstream mechanisms to facilitate EGCG-induced anti-invasion effects. These results suggest that EGCG may serve as a therapeutic agent to inhibit HGF-induced invasion in hypopharyngeal carcinoma patients.

Autoimmunity in the brain: the pathogenesis insight from cell biology

The aim of the study is to explore the relationship between leakage of the blood-brain barrier and inflammation, the reason why demyelination occurs--seemingly in the absence of an antigen-specific immune response that requires explanation if a coherent account of an inflammatory-mediated demyelination is to be achieved. In this study the cellular biology of the glial cells important for the synthesis and maintenance of central nervous system (CNS) myelin and their inter-relations with other environmental cells (neuronal, microglial, olygodendroglial, astrocytes, endothelial, epithelial, T lymphocytes, B lymphocytes, monocytes, and macrophages) and with the compound of the extracellular matrix (ECM) during the development of an autoimmune inflammatory and demyelinating processes in the brain was analyzed. Upon activation in the peripheral tissue, immune cells reach their target organ via bloodstream and interacting with blood vessels wall components in the absence of exogenous stimulus mount an attack against the local milleu, which is the starting point of a pathogenic inflammatory reaction. Each of these contacts may trigger profuse secretion of cytokines, chemokines, and other soluble inflammatory mediators, which in the CNS by activating of local glial cells and by attracting and stimulating blood-borne monocyte/macrophages can act directly on neural cells and will cause their demyelination.

High expression of plasminogen activator inhibitor-2 (PAI-2) is a predictor of improved survival in patients with pancreatic adenocarcinoma

OBJECTIVE

Recent findings suggest that the urokinase-type plasminogen activator (uPA), its receptor (uPAR), plasminogen activator inhibitor-1 (PAI-1), and -2 (PAI-2) play key roles in cancer invasion. The prognostic value of components of this system is well established in breast cancer. However, little is known of its involvement in pancreatic cancer (PC).

METHODS

Quantitative real-time polymerase chain reaction (Q-RT-PCR) was used on tissue-banked specimens and immunohistochemistry (IHC) on paraffin specimens was used to measure expression of uPA, uPAR, PAI-1, and PAI-2 proteins in 46 PC and 12 cystadenoma specimens. Results were related to survival using Cox's proportional hazards testing.

RESULTS

Increased expression of uPA, uPAR, and PAI-1 in PC tissue were independently associated with a higher Union Internationale Contre le Cancer [International Union Against Cancer (UICC)] tumor stage (P < 0.001) and were intercorrelated (P < 0.001). Overexpression of uPAR indicated reduced survival (P = 0.03). Conversely, PAI-2 messenger ribonucleic acid (mRNA) overexpression, which occurred in 21 of 46 tumors, negatively correlated with tumor size (P = 0.008) and survival (P < 0.007) but not with uPA, uPAR, or tumor stage. There was good agreement between PAI-2 mRNA value and IHC score (P < 0.001). Using Cox's stepwise analysis, PAI-2 mRNA value (HR = 0.24; P = 0.001) and UICC tumor stage (HR = 2.014; P = 0.001) independently predicted survival. An IHC score for PAI-2 of 3+ or 4+ also independently predicted improved survival (HR = 2.72; P = 0.025).

CONCLUSIONS

The uPA/uPAR/PAI-1 system is activated in advanced pancreatic cancer and may account for the tumor's aggressive behavior, whereas PAI-2 expression appears to be independent of uPA/uPAR/PAI-1 and is associated with improved prognosis. Because of its intercorrelation with mRNA expression, PAI-2 IHC may be used as an indicator of survival.

Cancer and thrombosis: from molecular mechanisms to clinical presentations

Although the bidirectional association between cancer and venous thromboembolism (VTE) has been known for almost two centuries, recent advances in our understanding of the clinical, laboratory, and epidemiologic aspects of this association have created a renewed interest in this topic. This review consists of two parts. The first part discusses the occurrence, determinants and significance of VTE in those with cancer, as well as the risk of developing and the possible need to detect cancer in those presenting with VTE. The second part reviews the role of hemostatic constituents (coagulation and fibrinolytic proteins and platelets) in promoting growth and progression of cancer, as well as the effects and possible mechanisms of the low molecular weight heparins (LMWH) in this process.

Stimulation of human breast carcinoma cell invasiveness and urokinase plasminogen activator activity by glucose deprivation

Glucose deprivation has been shown to increase the invasive and metastatic potential of tumour cells. In the present study, we determined whether the enhanced tumour cell invasiveness resulting from glucose deprivation is linked to increased activity of enzymes required for extracellular matrix degradation. Results of in vitro invasion assays revealed that the invasiveness of human MDA-MB-231 and MCF-7 breast carcinoma cells and MCF-10A1 normal breast cells was, respectively, 3.9-, 2.9-, and 2.1-fold higher when they were incubated under glucose-deprivation (0.2 mM glucose) than when incubated under physiological blood glucose levels (5 mM). This effect of glucose deprivation on invasion correlated with increased urokinase plasminogen activator (uPA) and plasmin activity. Glucose deprivation did not increase the levels of gelatinase and plasminogen activator inhibitor-1 secretion, or the expression of cell-associated uPA receptor. To determine whether the increased invasiveness resulting from glucose deprivation is causally linked to increased uPA activity, invasion assays were conducted using MDA-MB-231 cells incubated in 0.2 mM or 5 mM glucose in the presence of a neutralising anti-uPA antibody. Results revealed that the anti-uPA antibody significantly inhibited invasion in a dose-dependent manner and to a much greater extent in cells incubated in 0.2 mM glucose than in cells incubated in 5 mM glucose. These results suggest that low glucose levels in malignant cancers increase tumour cell invasiveness by stimulating uPA and plasmin activity.

Epidermal growth factor promotes invasiveness of pancreatic cancer cells through NF-kappaB-mediated proteinase productions

OBJECTIVES

Overexpression of epidermal growth factor (EGF) and EGF receptor has been associated with progression and invasive phenotype in pancreatic cancer. However, the underlying molecular mechanism by which EGF worked in pancreatic cancer cells has been poorly understood. In this study, we determined the effect of EGF on the invasiveness and the related regulatory mechanism in two pancreatic cancer cell lines NOR-P1 and KP4.

METHODS

Invasion assay was performed to examine the invasiveness of tumor cells induced by EGF, and the expression of matrix metalloproteinase (MMP)-9, MMP-2, and plasminogen activator (uPA) was determined by reverse transcription-polymerase chain reaction and Western blot. Gelatin zymography was used to detect the activities of MMP-9 and MMP-2, and the nuclear factor-kappaB (NF-kappaB) binding activity was determined by electrophoretic mobility shift assay (EMSA).

RESULTS

EGF significantly increased the invasiveness of both cell lines but did not affect cell proliferation or adhesion. Increased invasiveness was associated with the induction of MMP-9 and uPA at both mRNA and protein levels. Furthermore, EGF stimulated NF-kappaB binding activity. Moreover, pretreatment of cells with NF-kappaB inhibitors, pyrrolidine dithiocarbamate or ibuprofen, markedly attenuated EGF-induced NF-kappaB activation. Subsequently, the EGF-induced MMP-9 and uPA expression and MMP-9 activity, as well as cell invasiveness, were also inhibited by these NF-kappaB inhibitors.

CONCLUSIONS

Our findings indicated that NF-kappaB-mediated MMP-9 and uPA induction was responsible for EGF-induced invasiveness in these pancreatic cancer cell lines and implicate that such anti-NF-kappaB therapy as the use of NF-kappaB inhibitors may contribute to the reduction of invasiveness of pancreatic cancer.

The pathogenesis of venous thromboembolism in cancer: emerging links with tumour biology

Venous thromboembolism (VTE) is a frequent complication in individuals with cancer and is considered to be a cause of substantial mortality. Epidemiological studies identify malignancy as an independent VTE risk factor and show that cancer patients are at increased risk of both initial and recurrent VTE events. The risk due to cancer is compounded by the effects of chemotherapy and other treatments. The pathogenesis of cancer-associated VTE is complex involving multiple interactions between tumours and various components of haemostasis. The development of a systemic hypercoagulable state is considered a key pathogenetic feature and is attributed to tumour expression of tissue factor and other procoagulants, activation of vascular cells by tumour-derived cytokines and adhesive interactions between tumour cells and host cells. An increasing body of evidence indicates that the activation of haemostasis in malignant disease contributes to tumour growth and progression by stimulation of intracellular signalling pathways. The interaction of tissue factor, thrombin and other coagulation factors with protease activated receptor (PAR) proteins expressed by tumour cells and host vascular cells leads to the induction of genes related to the processes of angiogenesis, cell survival and cell adhesion and migration.

Effect of portal hemodynamics on liver regeneration studied in a novel portohepatic shunt rat model

BACKGROUND

The role of portal hemodynamics on liver regeneration after partial hepatectomy is not fully understood. The aim of our study was to characterize the effects of portal hemodynamics using a novel rat model.

METHODS

We established a rat model of a portohepatic shunt with a 70% hepatectomy (PHS model), in which the portal pressure remained stable during and after the 70% hepatectomy. To assess the effect of portal hemodynamics on liver injury and regeneration in the first 24 hours, we compared PHS rats with those with a simple 70% hepatectomy.

RESULTS

Biochemical and histopathologic changes were similar between the 2 groups. Liver weight increased in the control, whereas it did not in the PHS group (P = .0021). Hepatocytes were enlarged in the control but not in the PHS group, although DNA synthesis was similar in both groups. Apoptotic hepatocytes increased markedly in PHS at 24 hours, whereas minimal apoptosis was noted throughout the course of the study in the control group. Hepatocyte growth factor increased similarly, except that it was not activated in PHS.

CONCLUSIONS

Our results suggested that a portal hyperdynamic state early after a 70% hepatectomy was necessary for liver regeneration through activation of hepatocyte growth factor, promoting hepatocyte hypertrophy and avoiding apoptosis, while DNA synthesis in hepatocytes was independent of portal hemodynamics.

Plasminogen activation/plasmin in rheumatoid arthritis: matrix degradation and more

Rheumatoid arthritis (RA) is one of the most common and most debilitating joint diseases, producing high personal, social, and economic costs.(1,2) Patients with RA suffer pain and functional losses, often followed by disability and premature death. Although the etiology of RA is unknown, substantial efforts have been directed toward studying the transition of the joint from normal to diseased. The maintenance of normal joint architecture and function requires equilibrium between the synthesis and degradation of the specialized extracellular matrices that make up bone, cartilage, and tendons. In RA, the balance of tissue remodeling is disturbed,(3) and excessive proteolytic degradation of the joint matrices leads to joint destruction.(4,5) The early phase of RA is characterized by the infiltration of immune and inflammatory cells into the synovium and by hyperplasia of the fibroblasts in the synovial lining. This leads to pannus formation, cartilage breakdown, and eventual bone destruction.(1,2) Through the use of an experimental mouse model of RA, Li and colleagues(6) have implicated plasmin as an essential component of the early phase of RA, as reported in this issue of The American Journal of Pathology.

Activated macrophages inhibit human cytotrophoblast invasiveness in vitro

Pre-eclampsia is associated with inadequate cytotrophoblast invasion and remodeling of the uterine spiral arterioles, as well as by an aberrant maternal immune response. This study determined the effect of activated macrophages and one of its products, tumor necrosis factor (TNF)-alpha, on cytotrophoblast invasiveness. Coculture with human lipopolysaccharide-activated macrophages decreased the ability of immortalized HTR-8/ SVneo human trophoblast cells to invade through reconstituted extracellular matrix (P < 0.05). This effect of activated macrophages on trophoblast invasiveness was paralleled by abrogation of a 55-kDa caseinolytic activity corresponding to prourokinase plasminogen activator (pro-uPA) and an increased secretion of plasminogen activator inhibitor 1 (PAI1), as determined by gel zymography and ELISA, respectively. Coculture with nonactivated macrophages did not significantly affect trophoblast invasiveness or pro-uPA and PAI1 secretion. Activated macrophages secreted detectable levels of TNF, and administration of exogenous TNF significantly decreased trophoblast invasiveness (P < 0.05), increased the secretion of PAI1 (P < 0.01), and completely inhibited the pro-uPA-associated caseinolytic activity by binding to the TNF receptor 1. Moreover, addition of up to 10 ng/ml of TNF did not increase the rate of apoptosis in HTR-8/SVneo cells. Finally, the increased secretion of PAI1 by trophoblast cells cocultured with activated macrophages was significantly inhibited when a neutralizing anti-TNF antibody was added to the cocultures. These results suggest that the aberrant presence of activated macrophages around uterine vessels may contribute to inadequate trophoblast invasion and remodeling of the uterine spiral arterioles. Thus, the presence of activated macrophages may be important in the etiology of pre-eclampsia.

Significant overexpression of urokinase-type plasminogen activator in pancreatic adenocarcinoma using real-time quantitative reverse transcription polymerase chain reaction

BACKGROUND AND AIMS

Overexpression of urokinase-type plasminogen activator (uPA) has been shown to be strongly associated with an increased metastatic potential and poor prognosis in a variety of human malignancies. It was hypothesized that uPA would be overexpressed in highly metastatic pancreatic cancer. The aims of this study were to analyze uPA mRNA expression in pancreatic cancer and to correlate this to the expression of uPA protein and to the stage of the disease.

METHODS

Twenty-one pancreatic adenocarcinoma, six ampullary carcinoma and 10 benign mucinous cystadenoma samples, all with adjacent normal tissue, were collected. uPA mRNA was measured using real-time quantitative reverse transcription polymerase chain reaction. Localization of uPA within normal and pancreatic tumor sections was subsequently confirmed using immunohistochemistry.

RESULTS

The median and range of the ratios of uPA mRNA measures between tumor tissue and non-involved pancreatic tissue was 17.1 (1.4-653.6) for pancreatic adenocarcinoma (P < 0.001), 3.9 (0.7-7.7) for ampullary carcinoma (P = 0.055) and 1.9 (0.6-5.9) for mucinous cystadenoma tissue (P = 0.052). uPA low tumors were associated with an exuberant stromal reaction, whereas uPA high tumors showed little stromal response. Immunohistochemistry confirmed that uPA protein was more prevalent in pancreatic adenocarcinoma tissue than in normal tissue and that it was membrane-bound. uPA mRNA expression was significantly associated with poorly differentiated pancreatic cancers (P < 0.05) and positively associated with tumor stage.

CONCLUSIONS

These observations suggest that significant overexpression of uPA correlates closely to the rapid progression and invasiveness of pancreatic cancer and that uPA may provide a future therapeutic target for pancreatic cancer treatment.