Suppression of invasion and peritoneal carcinomatosis of ovarian cancer cell line by overexpression of bikunin

Molecular and pathobiological insights of bikunin/UTI in cancer

Bikunin is a small chondroitin sulfate proteoglycan (PG) with Ser-protease inhibitory activity that plays pleiotropic roles in health and disease. It is involved in several physiological processes including stabilization of the extracellular matrix (ECM) of connective tissues and key reproductive events. Bikunin is also implicated in both acute and chronic inflammatory conditions and represents a non-invasive circulating and/or urinary (as Urinary Trypsin Inhibitor or UTI) biomarker. It exerts inhibitory effects on urokinase-type plasminogen activator (uPA) and its receptor (uPAR) mediating tumor invasiveness by a down-regulation of uPA mRNA expression, thus representing an anti-metastatic agent. However, only limited data on its potential as a diagnostic and/or prognostic marker of cancer have been reported so far. Recent technological advances in mass spectrometry-based proteomics have provided researchers with a huge amount of information allowing for large-scale surveys of the cancer proteome. To address such issues, we analyzed bikunin expression data across several types of tumors, by using UALCAN proteogenomic analysis portal. In this article we critically review the roles of bikunin in human pathobiology, with a special focus on its inhibitory effects and mechanisms in cancer aggressiveness as well as its significance as cancer circulating biomarker.

Application of Proteogenomics to Urine Analysis towards the Identification of Novel Biomarkers of Prostate Cancer: An Exploratory Study

Simple Summary

Prostate cancer (PCa) is one of the most common cancers. Due to the limited and invasive approaches for PCa diagnosis, it is crucial to identify more accurate and non-invasive biomarkers for its detection. The aim of our study was to non-invasively uncover new protein targets for detecting PCa using a proteomics and proteogenomics approach. This work identified several dysregulated mutant protein isoforms in urine from PCa patients, some of them predicted to have a protective or an adverse role in these patients. These results are promising given urine’s non-invasive nature and offers an auspicious opportunity for research and development of PCa biomarkers.

Abstract

To identify new protein targets for PCa detection, first, a shotgun discovery experiment was performed to characterize the urinary proteome of PCa patients. This revealed 18 differentially abundant urinary proteins in PCa patients. Second, selected targets were clinically tested by immunoblot, and the soluble E-cadherin fragment was detected for the first time in the urine of PCa patients. Third, the proteogenome landscape of these PCa patients was characterized, revealing 1665 mutant protein isoforms. Statistical analysis revealed 6 differentially abundant mutant protein isoforms in PCa patients. Analysis of the likely effects of mutations on protein function and PPIs involving the dysregulated mutant protein isoforms suggests a protective role of mutations HSPG2*Q1062H and VASN*R161Q and an adverse role of AMBP*A286G and CD55*S162L in PCa patients. This work originally characterized the urinary proteome, focusing on the proteogenome profile of PCa patients, which is usually overlooked in the analysis of PCa and body fluids. Combined analysis of mass spectrometry data using two different software packages was performed for the first time in the context of PCa, which increased the robustness of the data analysis. The application of proteogenomics to urine proteomic analysis can be very enriching in mutation-related diseases such as cancer.

Loss of SPINT2 expression frequently occurs in glioma, leading to increased growth and invasion via MMP2

PURPOSE

High-grade gliomas (HGG) remain one of the most aggressive tumors, which is primarily due to its diffuse infiltrative nature. Serine proteases and metalloproteases are known to play key roles in cellular migration and invasion mechanisms. SPINT2, also known as HAI-2, is an important serine protease inhibitor that can affect MET signaling. SPINT2 has been found to be frequently downregulated in various tumors, whereby hypermethylation of its promoter appears to serve as a common mechanism. Here, we assessed the clinical relevance of SPINT2 expression and promoter hypermethylation in pediatric and adult HGG and explored its functional role.

METHODS

A series of 371 adult and 77 pediatric primary HGG samples was assessed for SPINT2 protein expression (immunohistochemistry) and promoter methylation (methylation-specific PCR) patterns. After SPINT2 knockdown and knock-in in adult and pediatric HGG cell lines, a variety of in vitro assays was carried out to determine the role of SPINT2 in glioma cell viability and invasion, as well as their mechanistic associations with metalloprotease activities.

RESULTS

We found that SPINT2 protein expression was frequently absent in adult (85.3%) and pediatric (100%) HGG samples. The SPINT2 gene promoter was found to be hypermethylated in approximately half of both adult and pediatric gliomas. Through functional assays we revealed a suppressor activity of SPINT2 in glioma cell proliferation and viability, as well as in their migration and invasion. These functions appear to be mediated in part by MMP2 expression and activity.

CONCLUSIONS

We conclude that dysregulation of SPINT2 is a common event in both pediatric and adult HGG, in which SPINT2 may act as a tumor suppressor.

Underexpression of α-1-microglobulin/bikunin precursor predicts a poor prognosis in oral squamous cell carcinoma

In the present study, in order to identify novel diagnostic biomarkers for the malignant behavior of oral squamous cell carcinoma (OSCC), we determined the proteomic profiles of several OSCC cell lines and keratinocytes by two-dimensional fluorescence difference gel electrophoresis and liquid chromatography tandem mass spectrometry. The protein expression level of α-1-microglobulin/bikunin precursor (AMBP) was found to be significantly lower in the OSCC cell lines than in the keratinocytes, and a significant decrease in AMBP mRNA expression was confirmed in the OSCC cell lines by RT-qPCR. To investigate the biological function of AMBP in OSCC, the cells were transiently transfected with an AMBP overexpression vector; the AMBP-overexpressing cells exhibited a significantly decreased invasion and migration in comparison to the mock-transfected control cells, although no significant changes in cell proliferation were observed. Immunohistochemistry revealed that the underexpression of AMBP was significantly associated with a high metastatic potential to cervical lymph nodes and a poor overall survival. Thus, the expression of AMBP is an independent predictive factor of cervical lymph node metastasis and a prognostic factor of overall survival, and it is involved in both cell invasion and metastasis in cervical lymph nodes in OSCC.

Synergism from the combination of ulinastatin and curcumin offers greater inhibition against colorectal cancer liver metastases via modulating matrix metalloproteinase-9 and E-cadherin expression

Liver metastasis is a major cause of mortality in colorectal cancer (CRC). The current study was to investigate the ability of ulinastatin (UTI) and curcumin (CUR) to inhibit CRC liver metastases via modulating matrix metalloproteinase-9 (MMP-9) and E-cadherin expression. Human CRC HCT-116 cells were treated with compounds individually and in combination in order to understand the effect on cell migration and invasion. The HCT-116 cell line was established to stably express luciferase and green fluorescent protein (GFP) by lentiviral transduction (HCT-116-Luc-GFP). We identified an anti-metastasis effect of UTI and CUR on a CRC liver metastasis mouse model. Tumor development and therapeutic responses were dynamically tracked by bioluminescence imaging. Expression of MMP-9 and E-cadherin in metastatic tumors was detected by immunohistochemical assay. Results of wound healing and cell invasion assays suggest that treatment with UTI, CUR, and UTI plus CUR, respectively, significantly inhibit HCT-116 cell migration and invasion. Furthermore, results of CRC hepatic metastasis on a nude mouse model showed that treatment with UTI, CUR alone, and a combination notably inhibited hepatic metastases from CRC and prolonged survival of tumor-bearing mice, especially in the UTI plus CUR group. These results suggest that the combination of UTI and CUR together may offer greater inhibition against metastasis of CRC.

Ulinastatin reduces cancer recurrence after resection of hepatic metastases from colon cancer by inhibiting MMP-9 activation via the antifibrinolytic pathway

High recurrence of colon cancer liver metastasis is observed in patients after hepatic surgery, and the cause is believed to be mostly due to the growth of residual microscopic metastatic lesions within the residual liver. Therefore, triggering the progression of occult metastatic foci may be a novel strategy for improving survival from colon cancer liver metastases. In the present study, we identified an anti-recurrence effect of ulinastatin on colon cancer liver metastasis in mice after hepatectomy. Transwell cell invasion assays demonstrated that ulinastatin significantly inhibited the in vitro invasive ability of colon cancer HCT116 cells. Moreover, gelatin zymography and ELISA analysis showed that MMP-9 activity and plasmin activity of colon cancer HCT116 cells were inhibited by ulinastatin, respectively. Furthermore, in vivo BALB/C nu/nu mice model indicated that ulinastatin effectively reduced recurrence after resection of hepatic metastases from colon cancer. The optimum timing for ulinastatin administration was one week after hepatectomy. Taken together, our findings point to the potential of ulinastatin as an effective approach in controlling recurrence of hepatic metastases from colon cancer after hepatectomy via its anti-plasmin activity.

Urine of patients with early prostate cancer contains lower levels of light chain fragments of inter-alpha-trypsin inhibitor and saposin B but increased expression of an inter-alpha-trypsin inhibitor heavy chain 4 fragment

The present study was aimed at the identification of proteins that are differentially expressed in the urine of patients with prostate cancer (PCa), those with benign prostatic hyperplasia (BPH) and age-matched healthy male control subjects. Using a combination of 2DE and MS/MS, significantly lower expression of urinary saposin B and two different fragments of inter-alpha-trypsin inhibitor light chain (ITIL) was demonstrated in the PCa patients compared to the controls. However, only one of the ITIL fragments was significantly different between the PCa and BPH patients. When image analysis was performed on urinary proteins that were transferred onto NC membranes and detected using a lectin that binds to O-glycans, a truncated fragment of inter-alpha-trypsin inhibitor heavy chain 4 was the sole protein found to be significantly enhanced in the PCa patients compared to the controls. Together, these urinary peptide fragments might be useful complementary biomarkers to indicate PCa as well as to distinguish it from BPH, although further epidemiological evidence on the specificity and sensitivity of the protein candidates is required.

PIVL, a new serine protease inhibitor from Macrovipera lebetina transmediterranea venom, impairs motility of human glioblastoma cells

A novel Kunitz-type serine proteinase inhibitor, termed PIVL, was purified to homogeneity from the venom of the Tunisian snake Macrovipera lebetina transmediterranea. It is a monomeric polypeptide chain cross-linked by three disulfide linkages with an isotope-averaged molecular mass of 7691.7 Da. The 67-residue full-length PIVL sequence was deduced from a venom gland cDNA clone. Structurally, PIVL is built by a single Kunitz/BPTI-like domain. Functionally, it is able to specifically inhibit trypsin activity. Interestingly, PIVL exhibits an anti-tumor effect and displays integrin inhibitory activity without being cytotoxic. Here we show that PIVL is able to dose-dependently inhibit the adhesion, migration and invasion of human glioblastoma U87 cells. Our results also show that PIVL impairs the function of αvβ3 and to a lesser extent, the activity of αvβ6, αvβ5, α1β1 and α5β1 integrins. Interestingly, we demonstrate that the (41)RGN(43) motif of PIVL is likely responsible for its anti-cancer effect. By using time lapse videomicroscopy, we found that PIVL significantly reduced U87 cells motility and affected cell directionality persistence by 68%. These findings reveal novel pharmacological effects for a Kunitz-type serine proteinase inhibitor.

Urinary trypsin inhibitor as a therapeutic option for endotoxin-related inflammatory disorders

IMPORTANCE OF THE FIELD

Urinary trypsin inhibitor (UTI), a serine protease inhibitor, has been widely used as a drug for patients with inflammatory disorders such as pancreatitis, shock and disseminated intravascular coagulation (DIC). Previous in vitro studies have demonstrated that serine protease inhibitors may have anti-inflammatory properties at sites of inflammation. However, the therapeutic effects of UTI in vivo remain unclarified, as commercial UTI has been developed to act against humans, with the activity and selectivity toward the relevant animal UTI being less characterized.

AREAS COVERED IN THIS REVIEW

In this review, we introduce the roles of UTI in experimental endotoxin (lipopolysaccharide; LPS)-related inflammatory disorders using UTI-deficient (-/-) and corresponding wild-type mice.

WHAT THE READER WILL GAIN

Our experiments using genetic approach suggest that endogenous UTI can protect against the systemic inflammatory response and subsequent organ injury induced by LPS, at least partly, through the inhibition of pro-inflammatory cytokine and chemokine expression, which provide important in vivo evidence and understanding about a protective role of UTI in inflammatory conditions.

TAKE HOME MESSAGE

Using genetically targeted mice selectively lacking UTI, UTI has been evidenced to provide an attractive 'rescue' therapeutic option for endotoxin-related inflammatory disorders such as DIC, acute lung injury and acute liver injury.

Epigenetic inactivation and tumor suppressor activity of HAI-2/SPINT2 in gastric cancer

Hepatocyte growth factor (HGF) activator inhibitor type 2 (HAI-2/SPINT2) encodes Kunitz-type protease inhibitor that regulates HGF activity. Inspection of the human HAI-2/SPINT2 locus uncovered a large and dense CpG island within the 5' region of this gene. Analysis of cultured human gastric tumor lines indicated that HAI-2/SPINT2 expression is either undetectable or in low abundance in several lines; however, enhanced gene expression was measured in cells cultured on the DNA demethylating agent 5-aza-2'-deoxycytidine. Bisulfite DNA sequencing confirmed the densely methylated HAI-2/SPINT2 promoter region. Forced expression of HAI-2/SPINT2 induced cell apoptosis, suppressed anchorage independent growth in vitro and tumor growth in vivo. We investigated HAI-2/SPINT2 aberrant methylation in patients with gastric cancer. The HAI-2/SPINT2 methylation was found preferentially in cancerous tissues (30 of 40, 75%) compared with nontumor tissues (no methylation was detected), indicating that this aberrant characteristic is common in gastric malignancies. In conclusion, epigenetic inactivation of HAI-2/SPINT2 is a common event contributing to gastric carcinogenesis and may be a potential biomarker for gastric cancer.

Suppression of ADAM17-mediated Lyn/Akt pathways induces apoptosis of human leukemia U937 cells: Bungarus multicinctus protease inhibitor-like protein-1 uncovers the cytotoxic mechanism

Cell surface proteases have been demonstrated to play an important role in facilitating cell invasion into the extracellular matrix and may contribute significantly to extracellular matrix degradation by metastatic cancer cells. Abundant expression of these enzymes is associated with poor prognosis. Thus, protease inhibitors that repress cell surface proteases may be applicable to cancer therapy. Because soybean Kunitz-type trypsin inhibitor has been found to induce apoptotic death of human leukemia Jurkat cells, anti-leukemia activity of Bungarus multicinctus protease inhibitor-like protein-1 (PILP-1) is thus examined. PILP-1 induced apoptosis of human leukemia U937 cells, characteristic of loss of mitochondrial membrane potential, degradation of procaspase-8, and production of t-Bid. FADD down-regulation neither restored viability of PILP-1-treated cells nor attenuated production of active caspase-8 and t-Bid in PILP-1-treated cells, suggesting that the death receptor-mediated pathway was not involved in the cytotoxicity of PILP-1. It was found that PILP-1-evoked p38 MAPK activation and ERK inactivation led to PILP-1-induced cell death and down-regulation of ADAM17. Knockdown of ADAM17 by siRNA induced death of U937 cells and inactivation of Lyn and Akt. Immunoprecipitation suggested that ADAM17 and Lyn form complexes. Overexpression of ADAM17, LynY507F (gain of function), and constitutively active Akt suppressed the cytotoxic effects of PILP-1. PILP-1-elicited inactivation of Lyn and Akt was abrogated in cells with overexpressed ADAM17 or LynY507F. Taken together, our data indicate that ADAM17-mediated activation of Lyn/Akt maintains the viability of U937 cells and that suppression of the pathway is responsible for PILP-1-induced apoptosis.

Pathophysiology and biology of peritoneal carcinomatosis

Peritoneal carcinomatosis represents a devastating form of cancer progression with a very poor prognosis. Its complex pathogenesis is represented by a dynamic process comprising several steps. To the best of our knowledge pathogenesis can be partly explained by 3 major molecular pathways: (1) dissemination from the primary tumor; (2) primary tumor of peritoneum; and (3) independent origins of the primary tumor and peritoneal implants. These are not mutually exclusive and combinations of different mechanisms could occur inside a single case. There are still several aspects which need explanation by future studies. A comprehensive understanding of molecular events involved in peritoneal carcinomatosis is of paramount importance and should be systematically pursued not only to identify novel strategies for the prevention of the condition, but also to obtain therapeutic advances, through the identification of surrogate markers of prognosis and development of future molecular targeted therapies.

Drug development against metastasis-related genes and their pathways: a rationale for cancer therapy

It is well recognized that the majority of cancer related deaths is caused by metastatic diseases. Therefore, there is an urgent need for the development of therapeutic intervention specifically targeted to the metastatic process. In the last decade, significant progress has been made in this research field, and many new concepts have emerged that shed light on the molecular mechanism of metastasis cascade which is often portrayed as a succession of six distinct steps; localized invasion, intravasation, translocation, extravasation, micrometastasis and colonization. Successful metastasis is dependent on the balance and complex interplay of both the metastasis promoters and suppressors in each step. Therefore, the basic strategy of our interventions is aimed at either blocking the promoters or potentiating the suppressors in this disease process. Toward this goal, various kinds of antibodies and small molecules have been designed. These include agents that block the ligand-recepter interaction of metastasis promoters (HGF/c-Met), antagonize the metastasis-promoting enzymes (AMF, uPA and MMP) and inhibit the transcriptional activity of metastasis promoter (beta-Catenin). On the other hand, the intriguing roles of metastasis suppressors and their signal pathways have been extensively studied and various attempts have been made to potentiate these factors. Small molecules have been developed to restore the expression or mimic the function of metastasis-suppressor genes such as NM23, E-cadherin, Kiss-1, MKK4 and NDRG1, and some of them are under clinical trials. This review summarizes our current understanding of the molecular pathway of tumor metastasis and discusses strategies and recent development of anti-metastatic drugs.

Metastatic progression and gene expression between breast cancer cell lines from African American and Caucasian women

African American (AA) women have a lower overall incidence of breast cancer than do Caucasian (CAU) women, but a higher overall mortality. Little is known as to why the incidence of breast cancer is lower yet mortality is higher in AA women. Many studies speculate that this is only a socio-economical problem. This investigation suggests the possibility that molecular mechanisms contribute to the increased mortality of AA women with breast cancer. This study investigates the expression of 14 genes which have been shown to play a role in cancer metastasis. Cell lines derived from AA and CAU patients were analyzed to demonstrate alterations in the transcription of genes known to be involved in cancer and the metastatic process. Total RNA was isolated from cell lines and analyzed by RT-PCR analysis. Differential expression of the 14 targeted genes between a spectrum model (6 breast cancer cell lines and 2 non-cancer breast cell lines) and a metastasis model (12 metastatic breast cancer cell lines) were demonstrated. Additionally, an in vitro comparison of the expression established differences in 5 of the 14 biomarker genes between African American and Caucasian breast cell lines. Results from this study indicates that altered expression of the genes Atp1b1, CARD 10, KLF4, Spint2, and Acly may play a role in the aggressive phenotype seen in breast cancer in African American women.

Bikunin (Urinary Trypsin Inhibitor): Structure, Biological Relevance, And Measurement

Inflammatory processes, such as phagocytosis, coagulation, and vascular dilation, promote the release of serine proteases by neutrophils, macrophages, mast cells, lymphocytes, and the epithelial or endothelial cells. These proteases further facilitate the release of inflammatory cytokines and growth factors as well as take part in signal-cell proliferation through protease-activated receptors (PARs). Controlling the action of this cascade is necessary to prevent further damage to the normal tissues. One of the main anti-inflammatory response mediators is bikunin (Bik) that is responsible for inhibiting the activity of many serine proteases such as trypsin, thrombin, chymotrypsin, kallikrein, plasmin, elastase, cathepsin, Factors IXa, Xa, XIa, and XlIa. During the acute-phase response, Bik is released into plasma from proinhibitors primarily due to increased elastase activity. Bik is a glycoprotein, also referred to as urinary trypsin inhibitor, which in plasma inhibits the trypsin family of serine proteases by binding to either of the two Kunitz-binding domains. Bik also accumulates in urine. In conditions such as infection, cancer, tissue injury during surgery, kidney disease, vascular disease, coagulation, and diabetes, the concentrations of Bik in plasma and urine are increased. Several trypsin inhibitory assays for urine and immunoassays for both blood and urine have been described for measuring Bik. In addition to presenting the synthesis, structure, and pathophysiology of Bik, we will summarize various diagnostic approaches for measuring Bik. Analysis of Bik may provide a rapid approach in assessing various conditions involving the inflammatory processes.

Adenovirus-mediated expression of tissue factor pathway inhibitor-2 inhibits endothelial cell migration and angiogenesis

OBJECTIVE

Extracellular matrix (ECM) remodeling during angiogenesis is accomplished through plasmin-dependent pericellular proteolysis and through the action of matrix metalloproteinases (MMPs). Because tissue factor pathway inhibitor-2 (TFPI-2), a Kunitz-type protease inhibitor with prominent ECM localization, inhibits plasmin and MMPs activity, we investigated the role of TFPI-2 in endothelial cell (EC) migration and angiogenesis.

METHODS AND RESULTS

Real-time polymerase chain reaction and immunostaining showed that the expression of TFPI-2 mRNA and protein was upregulated in migrating ECs. The effect of TFPI-2 on angiogenesis was studied in mouse models of Matrigel and polyvinylalcohol sponge implants by overexpressing TFPI-2 through infection with a replication-deficient adenovirus (AdTFPI-2). Using (immuno)fluorescence and confocal microscopy we observed that TFPI-2 reduced neovascularization and promoted ECM deposition. Lateral cell migration and capillary tube formation in vitro also were impaired by TFPI-2, a process reversed by anti-TFPI-2 antibodies. Increased apoptosis occurred both in AdTFPI-2-treated ECs and in the mouse implants. Zymography and assays in the absence of plasminogen confirmed plasmin inhibition as a main mechanism through which TFPI-2 inhibits EC migration.

CONCLUSIONS

Our data suggest that TFPI-2 may be an important regulator of aberrant angiogenesis associated with tumor growth/metastasis, cardiovascular diseases, chronic inflammation, or diabetes.

Gene expression profiling of human ovarian tumours

There is currently a lack of reliable diagnostic and prognostic markers for ovarian cancer. We established gene expression profiles for 120 human ovarian tumours to identify determinants of histologic subtype, grade and degree of malignancy. Unsupervised cluster analysis of the most variable set of expression data resulted in three major tumour groups. One consisted predominantly of benign tumours, one contained mostly malignant tumours, and one was comprised of a mixture of borderline and malignant tumours. Using two supervised approaches, we identified a set of genes that distinguished the benign, borderline and malignant phenotypes. These algorithms were unable to establish profiles for histologic subtype or grade. To validate these findings, the expression of 21 candidate genes selected from these analyses was measured by quantitative RT–PCR using an independent set of tumour samples. Hierarchical clustering of these data resulted in two major groups, one benign and one malignant, with the borderline tumours interspersed between the two groups. These results indicate that borderline ovarian tumours may be classified as either benign or malignant, and that this classifier could be useful for predicting the clinical course of borderline tumours. Immunohistochemical analysis also demonstrated increased expression of CD24 antigen in malignant versus benign tumour tissue. The data that we have generated will contribute to a growing body of expression data that more accurately define the biologic and clinical characteristics of ovarian cancers.

Hepatocyte growth factor activation inhibitors (HAI-1 and HAI-2) regulate HGF-induced invasion of human breast cancer cells

Hepatocyte growth factor (HGF) plays a plethora of roles in cancer metastasis and tumour growth. The interaction between tumour cells and their surrounding stromal environment is a crucial factor regulating tumour invasion and metastasis. Stromal fibroblasts are the main source of HGF in the body, and release HGF as an inactive precursor (pro-HGF). HGF activator (HGFA), matriptase, urokinase-type plasminogen activator and hepsin are the main factors responsible for converting pro-HGF into active HGF. HAI-1 and HAI-2 are 2 novel Kunitz-type serine protease inhibitors that regulate HGF activity through inhibition of HGFA, matriptase and hepsin action. Recent studies demonstrate that HAI-1 and HAI-2 may also potently inhibit a number of other pro-metastatic serine proteases and therefore have direct bearing on the spread of tumours. Our study examined the potential of these HAI's to suppress the influence of HGF and regulate cancer metastasis. We generated a retroviral expression system that induced HAI expression in a human fibroblast cell line. Forced expression of either HAI-1 or HAI-2 in these fibroblasts resulted in a dramatic decrease in the production of bioactive hepatocyte growth factor (HGF). This reduction in HGF activity subsequently suppressed HGF's metastatic influence on breast cancer cells. To further assess the anti-cancer properties of HAI-1 and HAI-2 we generated recombinant HAI proteins. These recombinant HAI proteins possessed the ability to potently quench HGF activity. We also demonstrate that these recombinant HAI's suppressed fibroblast-mediated breast cancer invasion. An additional ribozyme transgenes study revealed that elimination of HAI-1 and HAI-2 expression, in an MDA-MB-231 breast cancer cell line, significantly enhanced the migratory, proliferative and invasive nature of these breast cancer cells. Overall, our data demonstrates the important roles of HAI-1 and HAI-2 in cancer metastasis, and reveals that these serine protease inhibitors display strong therapeutic potential.

Enhanced spontaneous metastasis in bikunin-deficient mice

Previously, we showed that bikunin, a Kunitz-type protease inhibitor, inhibits invasion and metastasis in several types of cancer cells possibly through suppression of upregulation of urokinase-type plasminogen activator (uPA) expression. Bikunin corresponds to a light chain of the inter-alpha inhibitor. To explore critical role of endogenous bikunin, we used bikunin knockout (Bik-/-) mice. Here, we show that 1) higher frequency of spontaneous 3LL lung metastasis was observed in Bik-/- mice compared to Bik+/+ mice, suggesting that bikunin deficiency increases the sensitivity of mice to lung metastasis; 2) administration of exogenous bikunin caused a significant reduction of lung metastasis in Bik-/- and Bik+/+ mice; 3) primary and metastatic tumors significantly upregulated uPA and PAI-1 expression in Bik-/- mice relative to Bik+/+ mice at least through phosphorylation of ERK1/2 and 4) exogenous bikunin suppressed phosphorylation of ERK1/2 and upregulation of uPA and PAI-1 expression in 3LL cells in response to G-CSF. These data allow us to conclude that the increased sensitivity of Bik-/- mice to lung metastasis in vivo is due to a lack of circulating proteins of the inter-alpha inhibitor family, especially bikunin.

Oxalate-inducible AMBP gene and its regulatory mechanism in renal tubular epithelial cells

The AMBP [A1M (alpha1-microglobulin)/bikunin precursor] gene encodes two plasma glycoproteins: A1M, an immunosuppressive lipocalin, and bikunin, a member of plasma serine proteinase inhibitor family with prototypical Kunitz-type domain. Although previously believed to be constitutively expressed exclusively in liver, the present study demonstrates the induction of this gene by oxalate in porcine proximal tubular LLC-PK1 cells and rat kidney. In liver, the precursor protein is cleaved in the Golgi network by a furin-like enzyme to release constituent proteins, which undergo glycosylation before their export from the cell. In the renal tubular cells, A1M and bikunin co-precipitate, indicating lack of cleavage of the precursor protein. As the expression of the AMBP gene is regulated by A1M-specific cis elements and transcription factors, A1M protein was studied as a representative of AMBP gene expression in renal cells. Oxalate treatment (500 microM) resulted in a time- and dose-dependent induction of A1M protein in LLC-PK1 cells. Of the four transcription factors, HNF-4 (hepatocyte nuclear factor-4) has been reported previously to be a major regulator of AMBP gene expression in liver. Electrophoretic mobility-shift assay, supershift assay, immunoreactivity assay and transfection-based studies showed the presence of an HNF-4 or an HNF-4-like protein in the kidney, which can affect the expression of the AMBP gene. In situ hybridization and immunocytochemical studies showed that the expression of this gene in kidney was mainly restricted to cells lining the renal tubular system.

Transcriptome analysis of human gastric cancer

To elucidate the genetic events associated with gastric cancer, 124,704 cDNA clones were collected from 37 human gastric cDNA libraries, including 20 full-length enriched cDNA libraries of gastric cancer cell lines and tissues from Korean patients. An analysis of the collected ESTs revealed that 97,930 high-quality ESTs coalesced into 13,001 clusters, of which 11,135 clusters (85.6%) were annotated to known ESTs. The analysis of the full-length cDNAs also revealed that 4862 clusters (51.7%) contained at least one putative full-length cDNA clone with an initiation codon, with the average length of the 5' UTR of 140 bp. A large number appear to have a diverse transcription start site (TSS). An examination of the TSS of some genes, such as TEGT and GAPD, using 5' RACE revealed that the predicted TSSs are actually found in human gastric cancer cells and that several TSSs differ depending on the specific gastric cell line. Furthermore, of the human gastric ESTs, 766 genes (9.5%) were present as putative alternatively spliced variants. Confirmation of the predicted spliced isoforms using RT-PCR showed that the predicted isoforms exist in gastric cancer cells and some isoforms coexist in gastric cell lines. These results provide potentially useful information for elucidating the molecular mechanisms associated with gastric oncogenesis.

Suppression of urokinase expression and invasion by a soybean Kunitz trypsin inhibitor are mediated through inhibition of Src-dependent signaling pathways

A soybean Kunitz trypsin inhibitor (KTI) interacts with cells as a negative modulator of the invasive cells. Using complementary pharmacological and genetic approaches, we provide novel findings regarding mechanisms by which KTI inhibits signaling pathways in ovarian cancer cells leading to invasion. Transforming growth factor-beta1 (TGF-beta1) directly activates Src kinase, which in turn activates ERK-phosphatidylinositol 3-kinase/Akt, the downstream targets of Src, for urokinase-type plasminogen activator (uPA) up-regulation in human ovarian cancer HRA cells. Preincubation of the HRA cells with KTI reduced the ability of TGF-beta1 to trigger the uPA expression at the gene level and at the protein level. To further elucidate the mechanism of the KTI-dependent suppressive effect of TGF-beta1-induced uPA expression and invasion, we investigated which signaling pathway transduced by KTI is responsible for this inhibitory effect. Here, we show that 1) KTI suppressed TGF-beta1-induced phosphorylation of Src, ERK1/2, and Akt by 40-60%; 2) KTI was insensitive to suppress the phosphorylation of ERK1/2 and Akt in the constitutively active (CA)-c-Src (Y529F) cells; 3) uPA expression was up-regulated in TGF-beta1-stimulated HRA cells and in unstimulated Y529F cells; 4) the addition of KTI reduced the TGF-beta1-induced increase of uPA gene and protein expression in the wild-type c-Src-transfected cells (in contrast, KTI could not inhibit uPA expression in the Y529F cells); and 5) CA-c-Src transfection resulted in a 2-fold increase in invasiveness, whereas KTI did not reduce invasion of the Y529F cells. Using additional complementary genetic approaches (CA-MEK1, CA-Akt, or kinase-dead-Akt), we conclude that KTI may suppress uPA expression and promotion of invasion possibly through one or more upstream targets of Src.

Pathophysiology and diagnostic value of urinary trypsin inhibitors

Inflammation is an important indicator of tissue injury. In the acute form, there is usually accumulation of fluids and plasma components in the affected tissues. Platelet activation and the appearance in blood of abnormally increased numbers of polymorphonucleocytes, lymphocytes, plasma cells and macrophages usually occur. Infectious disorders such as sepsis, meningitis, respiratory infection, urinary tract infection, viral infection, and bacterial infection usually induce an inflammatory response. Chronic inflammation is often associated with diabetes mellitus, acute myocardial infarction, coronary artery disease, kidney diseases, and certain auto-immune disorders, such as rheumatoid arthritis, organ failures and other disorders with an inflammatory component or etiology. The disorder may occur before inflammation is apparent. Markers of inflammation such as C-reactive protein (CRP) and urinary trypsin inhibitors have changed our appraisal of acute events such as myocardial infarction; the infarct may be a response to acute infection and (or) inflammation. We describe here the pathophysiology of an anti-inflammatory agent termed urinary trypsin inhibitor (uTi). It is an important anti-inflammatory substance that is present in urine, blood and all organs. We also describe the anti-inflammatory agent bikunin, a selective inhibitor of serine proteases. The latter are important in modulating inflammatory events and even shutting them down.

Tumor Suppressor Activity and Epigenetic Inactivation of Hepatocyte Growth Factor Activator Inhibitor Type 2/SPINT2 in Papillary and Clear Cell Renal Cell Carcinoma

Following treatment with a demethylating agent, 5 of 11 renal cell carcinoma (RCC) cell lines showed increased expression of hepatocyte growth factor (HGF) activator inhibitor type 2 (HAI-2/SPINT2/Bikunin), a Kunitz-type protease inhibitor that regulates HGF activity. As activating mutations in the MET proto-oncogene (the HGF receptor) cause familial RCC, we investigated whether HAI-2/SPINT2 might act as a RCC tumor suppressor gene. We found that transcriptional silencing of HAI-2 in RCC cell lines was associated with promoter region methylation and HAI-2/SPINT2 protein expression was down-regulated in 30% of sporadic RCC. Furthermore, methylation-specific PCR analysis revealed promoter region methylation in 30% (19 of 64) of clear cell RCC and 40% (15 of 38) of papillary RCC, whereas mutation analysis (in 39 RCC cell lines and primary tumors) revealed a missense substitution (P111S) in one RCC cell line. Restoration of HAI-2/SPINT2 expression in a RCC cell line reduced in vitro colony formation, but the P111S mutant had no significant effect. Increased cell motility associated with HAI-2/SPINT2 inactivation was abrogated by treatment with extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) and phospholipase C-gamma inhibitors, but not by an inhibitor of atypical protein kinase C. These findings are consistent with frequent epigenetic inactivation of HAI-2/SPINT2, causing loss of RCC tumor suppressor activity and implicate abnormalities of the MET pathway in clear cell and papillary sporadic RCC. This information provides opportunities to develop novel targeted approaches to the treatment of RCC.

Suppressing effects of daily oral supplementation of beta-glucan extracted from Agaricus blazei Murill on spontaneous and peritoneal disseminated metastasis in mouse model

PURPOSE

The Basidiomycete fungus Agaricus blazei Murill has traditionally been used as a health food for the prevention of cancer.

METHODS

We examined whether beta-(1-6)-D: -glucan extracted from A. blazei is a potential anticancer agent in an in vitro and in vivo animal model.

RESULTS

Here we show that (1) beta-glucan had cytotoxic effect against human ovarian cancer HRA cells, but not against murine Lewis lung cancer 3LL cells, in vitro; (2) beta-glucan promotes p38 MAPK activity for suppressing HRA cell proliferation and amplifying the apoptosis cascade; (3) beta-glucan stimulates translocation of the proapoptotic protein, Bax, from the cytosol to mitochondria, cytochrome c release, and subsequent caspase-9 activation; (4) treatment with SB203580, a p38 MAPK-specific inhibitor, suppresses beta-glucan-induced effects, indicating that activation of p38 MAPK is involved in the suppression of cell proliferation and mitochondrial activation-mediated cell death pathway; (5) in mice, oral supplementation with beta-glucan reduces pulmonary metastasis of 3LL cells and peritoneal disseminated metastasis of HRA cells and inhibits the growth of these metastatic tumors in lung or peritoneal cavity, in part, by suppressing uPA expression; and (6) in an in vivo experimental metastasis assay, however, the oral supplementation with beta-glucan after i.v. tumor cell inoculation did not reduce the number of lung tumor colonies.

CONCLUSION

Treatment with beta-glucan may be beneficial for cancer patients with or at risk for metastasis. The beta-glucan-dependent signaling pathways are critical for our understanding of anticancer events and development of cancer therapeutic agents.

Plasma bikunin as a favorable prognostic factor in ovarian cancer

PURPOSE

Bikunin is a multifunctional glycoprotein, which mediates suppression of tumor cell invasion and metastasis. The measurement of bikunin levels in the tissue of patients with malignant diseases has been introduced as a new and simple diagnostic tool for the evaluation of prognosis. The high bikunin expression in ovarian cancer tissue would enable the use of soluble bikunin protein present in the circulation of ovarian cancer patients as a biomarker of disease.

PATIENTS AND METHODS

We developed a double-antibody immunoassay for bikunin and detected its presence in normal human circulation. We quantified, by enzyme-linked immunosorbent assay and/or immunoblot assay bikunin in sera from 200 healthy women (controls), 200 patients with benign gynecologic diseases, and 327 patients with ovarian cancer before surgical removal of the tumor.

RESULTS

When the values of bikunin corresponding to the median were used as the cutoff value (11.5 microg/mL), low plasma bikunin was strongly associated with late-stage, suboptimal debulking with large residual tumor (> 2 cm) and low response to chemotherapy. The median survival time of the patients with a high bikunin level was more than 60 months as compared with 26 months among those with low bikunin level (P = .002). This difference corresponded to a 2.2-fold increased risk of dying for the lower plasma bikunin patients (hazard ratio, 0.45; P = .023) and remained significant in multivariate analysis (hazard ratio, 0.63; P = .041).

CONCLUSION

Preoperative plasma bikunin concentration is a strong and independent favorable prognostic marker for ovarian cancer.

Transforming growth factor-beta1-dependent activation of Smad2/3 and up-regulation of PAI-1 expression is negatively regulated by Src in SKOV-3 human ovarian cancer cells

The net balance between urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1) has been implicated in tumor cell invasion and metastasis. To elucidate the mechanism of the transforming growth factor-beta1 (TGF-beta1)-dependent up-regulation of PAI-1 expression, we investigated which signaling pathway transduced by TGF-beta1 is responsible for this effect. Here, we show (1) nontoxic concentrations of TGF-beta1 up-regulates uPA expression in HRA and SKOV-3 human ovarian cancer cells, (2) TGF-beta1 activates Smads (phosphorylation of Smad2 and nuclear translocation of Smad3) and subsequently up-regulates PAI-1 expression in HRA cells, whereas TGF-beta1 neither activates Smads nor up-regulates PAI-1 in SKOV-3 cells, (3) pharmacological Src inhibitor PP2 or antisense (AS) c-Src oligodeoxynucleotide (ODN) treatment significantly induces TGF-beta1-dependent activation of Smads, leading to PAI-1 synthesis, compared with controls, in SKOV-3 cells, (4) combination of TGF-beta1 and PP2, which activates PAI-1 expression and reduces uPA expression in SKOV-3, results in decreased invasiveness, (5) pharmacological inhibitors for mitogen-activated protein kinase (MAPK) (PD98059) and phosphoinositide-3-kinase (PI3K) (LY294002 and wortmannin) or AS-PI3K ODN transfection do not affect TGF-beta1-induced Smad signaling and up-regulation of PAI-1 expression in SKOV-3 cells pretreated with PP2, and (6) the induction of PAI-1 protein was partially inhibited by an inhibitor of Sp1-DNA binding, mithramycin, implicating, at least in part, Sp1 in the regulation of this gene by TGF-beta1. In conclusion, TGF-beta1-dependent activation of Smad2/3, leading to PAI-1 synthesis, may be negatively regulated by Src, but not its downstream targets MAPK and PI3K in SKOV-3 cells. These data also reflect the complex biological effect of uPA-PAI-1 system.

Signaling mechanisms responsible for lysophosphatidic acid-induced urokinase plasminogen activator expression in ovarian cancer cells

Lysophosphatidic acid (LPA) enhances urokinase plasminogen activator (uPA) expression in ovarian cancer cells; however, the molecular mechanisms responsible for this event have not been investigated. In this study, we used the invasive ovarian cancer SK-OV-3 cell line to explore the signaling molecules and pathways essential for LPA-induced uPA up-regulation. With the aid of specific inhibitors and dominant negative forms of signaling molecules, we determined that the G(i)-associated pathway mediates this LPA-induced event. Moreover, constitutively active H-Ras and Raf-1-activating H-Ras mutant enhance uPA expression, whereas dominant negative H-Ras and Raf-1 block LPA-induced uPA up-regulation, suggesting that the Ras-Raf pathway works downstream of G(i) to mediate this LPA-induced process. Surprisingly, dominant negative MEK1 or Erk2 displays only marginal inhibitory effect on LPA-induced uPA up-regulation, suggesting that a signaling pathway distinct from Raf-MEK1/2-Erk is the prominent pathway responsible for this process. In this report, we demonstrate that LPA activates NF-kappaB in a Ras-Raf-dependent manner and that blocking NF-kappaB activation with either non-phosphorylable IkappaB or dominant negative IkappaB kinase abolished LPA-induced uPA up-regulation and uPA promoter activation. Furthermore, introducing mutations to knock out the NF-kappaB binding site of the uPA promoter results in over 80% reduction in LPA-induced uPA promoter activation, whereas this activity is largely intact with the promoter containing mutations in the AP1 binding sites. Thus these results suggest that the G(i)-Ras-Raf-NF-kappaB signaling cascade is responsible for LPA-induced uPA up-regulation in ovarian cancer cells.

Overexpression of a hybrid gene consisting of the amino-terminal fragment of urokinase and carboxyl-terminal domain of bikunin suppresses invasion and migration of human ovarian cancer cellsin vitro

A Kunitz-type protease inhibitor, bikunin, is known to suppress the invasion and metastasis of cancer cells. HI8, a carboxyl-terminal domain of bikunin, is an active site of this glycoprotein. To increase its affinity for cancer cells, we constructed a chimeric gene, ATF-HI8, and investigated the anti-invasive and anti-migratory activity of ATF-HI8 on ovarian cancer cells. ATF-HI8-expressing plasmid and ATF-expressing plasmid were introduced into the highly invasive and metastatic ovarian cancer cell line HRA. The properties of the established cell line (HRA/ATF-HI8) were compared to those of the HRA/ATF and the HRA/luciferase (HRA/LUC, control) cell lines in terms of cell proliferation, invasion and migration. As a result, (i) there were no differences in cell proliferation between HRA/ATF-HI8 and HRA/LUC; (ii) the invasion and migration of HRA/ATF-HI8 cells were significantly inhibited compared to those of HRA/LUC cells; (iii) the migration, but not the invasion, of HRA/ATF cells was significantly inhibited compared to that of HRA/LUC. These results indicate that the overexpression of ATF-HI8 inhibits the invasion and migration of ovarian cancer cells without affecting cell proliferation and suggest that HI8 is involved in the anti-invasive and the anti-migratory activities, and the addition of ATF brought about the increase in the anti-migratory activity of HI8. The above findings suggest the applicability of therapeutic strategies targeting the inhibition of peritoneal invasion and dissemination of ovarian cancer by the use of the chimeric gene ATF-HI8.

A kunitz-type protease inhibitor bikunin disrupts ligand-induced oligomerization of receptors for transforming growth factor (TGF)-β and subsequently suppresses TGF-β signalings

We previously found that bikunin (bik), a Kunitz-type protease inhibitor, suppresses transforming growth factor-beta1 (TGF-beta1)-stimulated expression of urokinase-type plasminogen activator (uPA) in human ovarian cancer cells that lack endogenous bik. In the present study, we tried to elucidate the mechanism by which bik also inhibits plasminogen activator inhibitor type-1 (PAI-1) and collagen synthesis using human ovarian cancer cells. Here, we show that (a) there was an enhanced production of both uPA and PAI-1 in HRA cells in response to TGF-beta1; (b) the overexpression of bik in the cells or exogenous bik results in the inhibition of TGF-beta1 signaling as measured by phosphorylation of the downstream signaling effector Smad2, nuclear translocation of Smad3, and production of PAI-1 and collagen; (c) bik neither decreased expression of TGF-beta receptors (TbetaRI and TbetaRII) in either cell types nor altered the specific binding of 125I TGF-beta1 to the cells, indicating that the effects of bik in these cells are not mediated by ligand sequestration; (d) TbetaRI and TbetaRII present on the same cells exclusively form aggregates in TGF-beta1-stimulated cells; (e) co-treatment of TGF-beta1-stimulated cells with bik suppresses TGF-beta1-induced complex formation of TbetaRI and TbetaRII; and (f) a chondroitin-4-sulfate side chain-deleted bik (deglycosylated bik) does not inhibit TGF-beta1 signaling or association of type I/type II receptor. We conclude that glycosylated bik attenuates TGF-beta1-elicited signaling cascades in cells possibly by abrogating the coupling between TbetaRI and TbetaRII and that this probably provides the mechanism for the suppression of uPA and PAI-1 expression.

Upregulation of bikunin in tumor-infiltrating macrophages as a factor of favorable prognosis in ovarian cancer

OBJECTIVE

This study was carried out to clarify the localization of bikunin, a Kunitz-type protease inhibitor, and relation between expression of individual bikunin protein and ovarian cancer progression.

METHODS

We performed a retrospective study on the immunohistochemical expression of bikunin, urokinase-type plasminogen activator (uPA) and macrophages (CD68) in surgical specimens derived from 89 ovarian cancer patients to investigate correlations between the expression of bikunin and the clinicopathologic features and the prognosis. Furthermore, bikunin and uPA levels were measured by immunoblot analysis.

RESULTS

Immunohistochemical staining revealed that the localization of bikunin was similar to that of CD68 for macrophages. We identified high expression of bikunin in 40 (45%) of 89 ovarian cancers. The results of Western blot analysis showed a significant correlation with immunohistochemical data. There was a significant inverse correlation between bikunin levels and uPA levels in ovarian cancer tissues. High bikunin expression was an independent predictor for disease-free survival (P = 0.040) and overall survival (P = 0.042). The 5-year survival rate of the 49 patients with low bikunin expression in ovarian cancers was 39%, whereas that of the other 40 patients with high bikunin expression was 63%. In addition, macrophage-derived bikunin protein was induced by exogenous IL-6.

CONCLUSION

Bikunin derived from tumor-infiltrating macrophages might be a prognostic indicator as an antiinvasive factor supplied from macrophages within and around the tumor possibly through down-regulation of tumor-associated uPA expression.

Bikunin plus paclitaxel markedly reduces tumor burden and ascites in mouse model of ovarian cancer

Our previous studies of intraperitoneal ovarian carcinoma in a mouse model demonstrated that bikunin gene transfection could prevent ascites formation and intraperitoneal disseminated metastasis. Although ascites was almost completely inhibited, tumor burden was variably reduced. Several reports have indicated that bikunin may be involved in tumor survival. In the present study, the effectiveness of exogenous bikunin and the biodistribution characteristics of (125)I-bikunin were initially examined in a mouse model of human ovarian cancer HRA cells. The once-daily i.p. administration of bikunin significantly decreased progressive growth of HRA tumors and ascites formation in a dose-dependent manner. Maximal radioisotope tumor uptake peaked at 7.4% injected dose/g at 3 hr. Bikunin binding specificity was demonstrated by reduced tumor uptake after coinjection of excess nonradioactive bikunin. Bikunin was rapidly excreted renally. The bikunin therapy produced the significant inhibition in expression of the proteolysis (uPA and uPAR) and angiogenesis-related molecules (VEGF and bFGF). The second purpose of our study was to optimize the antimetastatic activity of bikunin in combination with paclitaxel against HRA cells growing orthotopically in mice. The once-daily i.p. administration of bikunin (25 microg/g body weight/day) in combination with paclitaxel (i.p., 100 microg/20 g at days 2 and 5) significantly decreased progressive growth of HRA cells in a synergistic fashion. In conclusion, combination therapy with bikunin plus paclitaxel may be an effective way to markedly reduce i.p. tumor growth and ascites in ovarian carcinoma possibly through suppression of uPA, uPAR, VEGF and bFGF expression.

Genetic downregulation of pregnancy-associated plasma protein-A (PAPP-A) by bikunin reduces IGF-I-dependent Akt and ERK1/2 activation and subsequently reduces ovarian cancer cell growth, invasion and metastasis

A Kunitz-type protease inhibitor, bikunin, downregulates expression of uPA and its receptor uPAR at the mRNA and protein levels in several types of tumor cells. Our recent work showed that, using a cDNA microarray analysis, pregnancy-associated plasma protein-A (PAPP-A) is a candidate bikunin target gene. To clarify how reduced levels of PAPP-A may confer repressed invasiveness, we transfected human ovarian cancer cell line HRA with antisense (AS)-PAPP-A cDNA and compared the properties of the transfected cells to those of parental HRA cells. Here, we show that regulation of uPA mRNA and protein by IGF-I depends on the PI3K and MAPK signaling pathways and phosphorylation of Akt and ERK1/2 is required for IGF-I-mediated cell invasion; that IGFBP-4 protease in HRA cells is identified as PAPP-A; that reduced PAPP-A expression is associated with the upregulation of IGFBP-4 expression; that higher intact IGFBP-4 levels were associated with low invasive potential and growth rate in AS-PAPP-A cells in response to IGF-I; that IGF-I stimulates Akt and ERK1/2 activation of both the control and antisense cells, but the relative potency and efficacy of IGF-I were lower in the antisense cells compared to the control; and that genetic downregulation of PAPP-A reduces the proliferation, invasion and metastasis of HRA cells. In conclusion, our data identify a novel role for PAPP-A as a bikunin target gene. IGF-I-induced IGFBP-4 proteolysis by PAPP-A may enhance cell growth and invasion through IGF-I-dependent Akt and ERK1/2 activation and subsequently upregulation of uPA.

Therapeutic efficacy of once-daily oral administration of a Kunitz-type protease inhibitor, bikunin, in a mouse model and in human cancer

BACKGROUND

Bikunin, a Kunitz-type protease inhibitor, specifically inhibits tumor invasion and metastasis.

METHODS

The authors initially evaluated the therapeutic efficacy of once-daily oral administration of different doses of bikunin against human ovarian carcinoma HRA cells growing in the peritonea of nude mice. For the in vivo studies, female 7-week-old nude mice were randomized to 1 of 4 groups: bikunin-treated groups (n = 9 in each group) received 3, 10, or 30 microg/g body weight per day bikunin for 7 days via gastrointestinal gavage, and a control group (n = 9) received the vehicle solution (phosphate-buffered saline) via gastrointestinal gavage. On Day 9, the abdominal cavity was examined by two observers who were blinded to treatment.

RESULTS

After oral administration, intact bikunin was detectable in mouse serum specimens at 3 and 6 hours. This was followed by a decline at 12 hours. The mice given bikunin at the highest dose level had a 40% decrease in tumor load. The highest uptake in the tumor was obtained with [125I]bikunin 12 hours postadministration. No effect on either food intake or body weight was observed in the treated versus sham groups. The current study was the first to report the potent activity of once-daily oral administration of bikunin against ovarian carcinoma. Next, the authors performed a Phase I trial to determine the maximum-tolerated dose (MTD) and safety of a once-daily oral administration schedule. The indication was locally advanced uterine cervical carcinoma after definitive treatment. An escalating dose (3, 10, and 30 mg/kg per day) of bikunin was administered orally to nine patients for 7 days. There were no dose-limiting toxicities and the MTD of the bikunin schedule was not defined. The authors also obtained preliminary data on its effect on urokinase-type plasminogen activator expression at the highest dose level.

CONCLUSIONS

Once-daily oral administration of bikunin was found to be safe in humans and exhibited signs of biologic activity.

The uristatin dipstick is useful in distinguishing upper respiratory from urinary tract infections

BACKGROUND

We determined the diagnostic value of the trypsin inhibitor, uristatin, that is commonly found in urine and plasma in patients with infections or inflammations of any kind.

METHODS

We collected urine specimens from patients with infections of the urinary or upper respiratory tract and from healthy controls. We also collected blood from patients with a likely upper respiratory tract infection and healthy controls. A bacterial count of >10(5) organisms/ml in urine was considered to represent infection rather than contamination.

RESULTS

The uristatin dipstick test in urine showed acceptable negative predictive values (NPV of up to 93%) for patients without infection or inflammation. Here, the dipsticks could eliminate some urine cultures. For those with infection or inflammation, the positive predictive values (PPV) of the dipsticks were lower (up to 57%). Including the leukocyte esterase and nitrite values increased the PPV of the dipsticks for those with disease.

CONCLUSIONS

The uristatin strip was more accurate than the leukocyte and nitrite dipsticks for predicting upper respiratory infections (URI) and C-reactive protein for those with infection or inflammation. The uristatin dipstick was able to detect both the bikunin and uristatin inhibitors.

Inhibition of tumor invasion by genomic down-regulation of matriptase through suppression of activation of receptor-bound pro-urokinase

Urokinase-type plasminogen activator (uPA) degrades the extracellular matrix and plays critical roles in tumor invasion and metastasis. Matriptase, a membrane-bound serine protease, was shown to activate uPA in a uPA receptor-free, solution-based study. We now investigate whether matriptase affects activation of receptor-bound uPA and contributes to the invasiveness of HRA human ovarian cancer cells in vitro and tumor behavior in nude mice. Here we show the following. 1) uPA expression was effectively stimulated by TGF-beta1 in HRA cells. 2) Antisense (AS)-matriptase transfection achieved a marked inhibition of receptor-bound pro-uPA activation without altering expression of uPA and uPA receptor mRNA and proteins, irrespective of whether cells were stimulated with TGF-beta1. 3) Tumor cell receptor-bound pro-uPA could be efficiently cleaved by matriptase to generate enzymatically active two-chain uPA. Thus, matriptase can substitute for plasmin in the proteolytic activation of pro-uPA to enzymatically active uPA. 4) The AS-matriptase-treated cells had a decreased ability to invade an extracellular matrix layer, as compared with control cells. 5) When the AS-matriptase-treated cells were injected intraperitoneally into nude mice, the mice developed smaller tumors. Our data identify a novel role for matriptase for activation of receptor-bound uPA.

Suppressing effects of dietary supplementation of soybean trypsin inhibitor on spontaneous, experimental and peritoneal disseminated metastasis in mouse model

The modifying effects of a Kunitz trypsin inhibitor (KTI) and a Bowman-Birk trypsin inhibitor (BBI), purified from soybean trypsin inhibitor, as dietary supplements on experimental and spontaneous pulmonary metastasis of murine Lewis lung carcinoma 3LL cells as well as peritoneal disseminated metastasis model in human ovarian cancer HRA cells were investigated in i.v., s.c. and i.p. injection models in mice. Seven groups of female C57BL/6 or nude mice were fed a basal diet (control group) or the basal diet supplemented with KTI or BBI (5, 15, or 50 g/kg). Here we show that, in an in vivo spontaneous metastasis assay, the diet supplementation with KTI (15 and 50 g/kg), but not with BBI, for 28 days immediately after s.c. tumor cell inoculation significantly inhibited the formation of lung metastasis in C57BL/6 mice in a dose-dependent manner. The inhibition of lung metastasis was not due to direct antitumor effects of KTI. In an in vivo experimental metastasis assay, the diet supplementation with KTI or BBI for 21 days after i.v. tumor cell inoculation did not reduce the number of lung tumor colonies. In addition, KTI (15 or 50 g/kg) treatment in a peritoneal disseminated metastasis model of HRA cells resulted in a 40% reduction in total tumor burden when compared with control animals. Immunoblot analysis revealed that KTI specifically reduced expression of uPA protein as well as phosphorylation of MAP kinase and PI3 kinase proteins in the cells stimulated with agonists (G-CSF for 3LL cells or TGF-beta1 for HRA cells). These results suggest that dietary supplementation of KTI more efficiently regulates the mechanism involved in the entry into vascular circulation of tumor cells (intravasation) than in extravasation during the metastatic process. KTI treatment may also be beneficial for ovarian cancer patients with or at risk for peritoneal disseminated metastasis; it greatly reduces tumor burden in part by inhibiting phosphorylation of MAP kinase and PI3 kinase, leading to suppression of uPA expression.

Transforming growth factor-beta1-dependent urokinase up-regulation and promotion of invasion are involved in Src-MAPK-dependent signaling in human ovarian cancer cells

Urokinase-type plasminogen activator (uPA) has been implicated in tumor cell invasion and metastasis. We reported previously that transforming growth factor (TGF)-beta1 induces a dose- and time-dependent up-regulation of uPA mRNA and protein in highly invasive human ovarian cancer cell line HRA, leading to invasion. To further elucidate the mechanism of the invasive effect of TGF-beta1, we investigated which signaling pathway transduced by TGF-beta1 is responsible for this effect. Here, we show that 1) nontoxic concentrations of TGF-beta1 activated Src kinase; 2) TGF-beta1 rapidly phosphorylates ERK1/2 and Akt, but not p38; 3) pharmacological Src inhibitor PP2 or antisense (AS) c-Src oligodeoxynucleotide (ODN) treatment reduced TGF-beta1-induced phosphorylation of ERK1/2 and Akt by 85-90% compared with controls; 4) pharmacological inhibition of MAPK by PD98059 abrogated TGF-beta1-mediated Akt stimulation, whereas TGF-beta1-induced ERK1/2 stimulation was not inhibited by PI3K inhibitor LY294002 or AS-PI3K ODN transfection; 5) up-regulation of uPA mRNA in response to TGF-beta1 was almost totally blocked by PP2 and PD98059 and partially ( approximately 55%) by LY294002; 6) TGF-beta1-induced uPA mRNA up-regulation was inhibited by treatment with AS ODNs to c-Src or PI3K by 90 or 60%, respectively, compared with control ODN treatment; and 7) blockade of the release of the transcription factor NF-kappaB by pyrrolidinedithiocarbamate reduced the TGF-beta1-induced activation of the uPA gene by approximately 65%. In addition, curcumin, a blocker of the transcriptional factor AP-1, partially (35%) canceled this effect. Taken together, these data support a role for TGF-beta1 activation of two distinct pathways (Src-MAPK-PI3K-NF-kappaB-dependent and Src-MAPK-AP-1-dependent) for TGF-beta1-dependent uPA up-regulation and promotion of invasion.

Genetic down-regulation of phosphoinositide 3-kinase by bikunin correlates with suppression of invasion and metastasis in human ovarian cancer HRA cells

Using a cDNA microarray analysis, we previously found that exposure of a highly invasive ovarian cancer cell line HRA with bikunin, a Kunitz-type protease inhibitor, or bikunin gene overexpression markedly reduced phosphoinositide kinase (PI3K) p85 gene expression, demonstrating that PI3K may be a candidate bikunin target gene. To clarify how reduced levels of PI3K may confer repressed invasiveness, we transfected HRA cells with PI3K p85 antisense-oligodeoxynucleotide (AS-ODN) and compared the properties of the transfected cells with those of parental cells and sense (S)-ODN cells. We have also demonstrated previously that transforming growth factor-beta1 (TGF-beta1) stimulates urokinase-type plasminogen activator (uPA)-dependent invasion and metastasis of HRA cells. Here, we show that 1) TGF-beta1 induced a rapid increase of the PI3K activity that was accompanied by increased expression (5-fold) of the uPA mRNA; 2) pharmacological inhibition of PI3K or AS-PI3K ODN transfection inhibited TGF-beta1-stimulated Akt phosphorylation; 3) both PI3K pharmacological inhibitors and forced expression of AS-PI3K ODN reduced TGF-beta1-stimulated uPA mRNA and protein expression by approximately 70% compared with controls; 4) concentrations of PI3K inhibitors, sufficient to inhibit uPA up-regulation, inhibited TGF-beta1-dependent HRA cell invasion; 5) the AS-PI3K ODN cells had a decreased ability to invade the extracellular matrix layer as compared with controls; and 6) when the AS-PI3K ODN cells were injected intraperitoneally into nude mice, the mice developed smaller intraperitoneal tumors and showed longer survival. We conclude that PI3K plays an essential role in promoting uPA-mediated invasive phenotype in HRA cells. Our data identify a novel role for PI3K as a bikunin target gene on uPA up-regulation and invasion.

Transforming growth factor-beta1 produced by ovarian cancer cell line HRA stimulates attachment and invasion through an up-regulation of plasminogen activator inhibitor type-1 in human peritoneal mesothelial cells

The processes of ovarian cancer dissemination are characterized by altered local proteolysis, cellular proliferation, cell attachment, and invasion, suggesting that the urokinase-type plasminogen activator (uPA) and its specific inhibitor (plasminogen activator inhibitor type-1 (PAI-1)) could be involved in the pathogenesis of peritoneal dissemination. We showed previously that expression of uPA and PAI-1 in the human ovarian cancer cell line HRA can be down-regulated by exogenous bikunin (bik), a Kunitz-type protease inhibitor, via suppression of transforming growth factor-beta1 (TGF-beta1) up-regulation and that overexpression of the bik gene can specifically suppress the in vivo growth and peritoneal dissemination of HRA cells in an animal model. We hypothesize that the plasminogen activator system in mesothelial cells can be modulated by HRA cells. To test this hypothesis, we used complementary techniques in mesothelial cells to determine whether uPA and PAI-1 expression are altered by exposure to culture media conditioned by HRA cells. Here we show the following: 1) that expression of PAI-1, but not uPA, was markedly induced by culture media conditioned by wild-type HRA cells but not by bik transfected clones; 2) that by antibody neutralization the effect appeared to be mediated by HRA cell-derived TGF-beta1; 3) that exogenous TGF-beta1 specifically enhanced PAI-1 up-regulation at the mRNA and protein level in mesothelial cells in a time- and concentration-dependent manner, mainly through MAPK-dependent activation mechanism; and 4) that mesothelial cell-derived PAI-1 may promote tumor invasion possibly by enhancing cell-cell interaction. This represents a novel pathway by which tumor cells can regulate the plasminogen activator system-dependent cellular responses in mesothelial cells that may contribute to formation of peritoneal dissemination of ovarian cancer.

The protease inhibitor bikunin, a novel anti-metastatic agent

Bikunin is a Kunitz-type protease inhibitor predominantly found in human amniotic fluid. In cancers, administration of bikunin may block tumor cell invasion by a direct inhibition of tumor cell-associated plasmin activity as well as by inhibiting urokinase-type plasminogen activator (uPA) expression at the gene and protein levels, possibly through suppression of CD44 dimerization and/or the MAP kinase signaling cascade. Treatment of cancer patients with bikunin may be beneficial in the adjuvant setting to delay the onset of metastasis development and/or in combination with cytotoxic agents to improve treatment efficacy in patients with advanced ovarian cancer.

Bikunin target genes in ovarian cancer cells identified by microarray analysis

Bikunin, a Kunitz-type protease inhibitor, could potentially suppress tumor cell invasion and metastasis. Our previous study revealed that overexpression of bikunin in a human ovarian cancer cell line, HRA, resulted in a down-regulation in uPA and uPAR gene expression. For identifying the full repertoire of bikunin-regulated genes, a cDNA microarray hybridization screening was conducted using mRNA from bikunin-treated or bikunin-transfected HRA cells. A number of bikunin-regulated genes were identified, and their regulation was confirmed by Northern blot analysis. Our screen identified 11 bikunin-stimulated genes and 29 bikunin-repressed genes. The identified genes can indeed be classified into distinct subsets. These include transcriptional regulators, oncogenes/tumor suppressor genes, signaling molecules, growth/cell cycle, invasion/metastasis, cytokines, apoptosis, ion channels, extracellular matrix proteins, as well as some proteases. This screen identified suppression of several genes such as CDC-like kinase, LIM domain binding, Ets domain transcription factor, Rho GTPase-activating protein, tyrosine phosphorylation-regulated kinase, hyaluronan-binding protein, matriptase, and pregnancy-associated plasma protein-A (PAPP-A), which have previously been implicated in enhancing tumor promotion. Northern blot analysis confirmed that several genes including matriptase and PAPP-A were down-regulated by bikunin by approximately 9-fold. Further, genetic inhibition of matriptase or PAPP-A could lead to diminished invasion. These results show that bikunin alters the pattern of gene expression in HRA cells leading to a block in cell invasion.