Cancer biology: extracellular proteinases in malignancy

Development of an Interleukin-12 Fusion Protein That Is Activated by Cleavage with Matrix Metalloproteinase 9

Interleukin-12 (IL-12) is a pleiotropic cytokine that has profound effects on many aspects of cell-mediated responses and can enhance antitumor responses in experimental models. IL-12 has been tested clinically, however, side-effects have limited its use. We are developing an attenuated form of IL-12 whose biological activity could be restricted to sites of tumors by taking advantage of overexpressed tumor proteases that can activate the cytokine. We constructed a panel of fusion proteins (FPs) consisting of IL-12 joined to a specific inhibitor connected by a protease cleavage sequence (cs). We first identified a panel of single-chain Fragment variable (scFv) that bind to 3 independent epitopes on IL-12 and then incorporated them into separate IL-12 FPs containing either a matrix metalloproteinase (MMP) cs or a scrambled (scram) control cs. The intact IL-12 FPs showed attenuation in IL-12 activity compared to free IL-12 in 2 separate in vitro functional assays; proliferation of CTLL-2 and interferon-gamma (IFN-γ) induction by spleen cells. Furthermore, the FP containing the MMPcs showed an increase in biological activity of IL-12 in vitro when cleaved by MMP9. This FP strategy could be applied to other immunomodulators and potentially reduce unwanted side-effects observed with systemic delivery thus improving cytokine immunotherapy strategies.

Mediators of Inflammation in Topical Therapy of Skin Cancers

Taking into consideration that the immune system plays a very important role in the development of melanoma and non-melanoma skin cancers, which have a high prevalence in immunosuppressed patients and after prolonged ultraviolet radiation, the interest in developing novel therapies, in particular targeting the inflammation in cancer, has increased in the past years. The latest data suggest that therapies such as imiquimod (IMQ), ingenol mebutate (IM), 5-fluorouracil (5-FU), retinoids, and nonsteroidal anti-inflammatory drugs (NSAIDs) have been used with success in the topical treatment of some cancers. Herein, we review the topical treatment targeting the inflammation in skin cancer and the mechanisms involved in these processes. Currently, various associations have shown a superior success rate than monotherapy, such as systemic acitretin and topical IMQ, topical 5-FU with tretinoin cream, or IMQ with checkpoint inhibitor cytotoxic T lymphocyte antigen 4. Novel therapies targeting Toll-like receptor-7 (TLR-7) with higher selectivity than IMQ are also of great interest.

STIM1/ORAI1-mediated Ca2+ Influx Regulates Enolase-1 Exteriorization

Tumor cells use broad spectrum proteolytic activity of plasmin to invade tissue and form metastatic foci. Cell surface-associated enolase-1 (ENO-1) enhances plasmin formation and thus participates in the regulation of pericellular proteolysis. Although increased levels of cell surface bound ENO-1 have been described in different types of cancer, the molecular mechanism responsible for ENO-1 exteriorization remains elusive. In the present study, increased ENO-1 protein levels were found in ductal breast carcinoma and on the cell surface of highly metastatic breast cancer cell line MDA-MB-231. Elevated cell surface-associated ENO-1 expression correlated with augmented MDA-MB-231 cell migratory and invasive properties. Exposure of MDA-MB-231 cells to LPS potentiated translocation of ENO-1 to the cell surface and its release into the extracellular space in the form of exosomes. These effects were independent of de novo protein synthesis and did not require the classical endoplasmic reticulum/Golgi pathway. LPS-triggered ENO-1 exteriorization was suppressed by pretreatment of MDA-MB-231 cells with the Ca(2+) chelator BAPTA or an inhibitor of endoplasmic reticulum Ca(2+)-ATPase pump, cyclopiazonic acid. In line with these observations, the stromal interaction molecule (STIM) 1 and the calcium release-activated calcium modulator (ORAI) 1-mediated store-operated Ca(2+) entry were found to regulate LPS-induced ENO-1 exteriorization. Pharmacological blockage or knockdown of STIM1 or ORAI1 reduced ENO-1-dependent migration of MDA-MB-231 cells. Collectively, our results demonstrate the pivotal role of store-operated Ca(2+) channel-mediated Ca(2+) influx in the regulation of ENO-1 exteriorization and thus in the modulation of cancer cell migratory and invasive properties.

New tools for the quantitative assessment of prodrug delivery and neurotoxicity

Systemic off-target toxicities, including neurotoxicity, are prevalent side effects in cancer patients treated with a number of otherwise highly efficacious anticancer drugs. In the current study, we have: (1) developed a new analytical metric for the in vivo preclinical assessment of systemic toxicities/neurotoxicity of new drugs and delivery systems; and (2) evaluated, in mice, the in vivo efficacy and toxicity of a versatile and modular NanoDendron (ND) drug delivery and imaging platform that we recently developed. Our paclitaxel-carrying ND prodrug, ND(PXL), is activated following proteolytic cleavage by MMP9, resulting in localized cytotoxic chemotherapy. Using click chemistry, we combined ND(PXL) with a traceable beacon, ND(PB), yielding ND(PXL)-ND(PB) that functions as a theranostic compound. In vivo fluorescence FRET imaging of this theranostic platform was used to confirm localized delivery to tumors and to assess the efficiency of drug delivery to tumors, achieving 25-30% activation in the tumors of an immunocompetent mouse model of breast cancer. In this model, ND-drug exhibited anti-tumor efficacy comparable to nab-paclitaxel, a clinical formulation. In addition, we combined neurobehavioral metrics of nociception and sensorimotor performance of individual mice to develop a novel composite toxicity score that reveals and quantifies peripheral neurotoxicity, a debilitating long-term systemic toxicity of paclitaxel therapy. Importantly, mice treated with nab-paclitaxel developed changes in behavioral metrics with significantly higher toxicity scores indicative of peripheral neuropathy, while mice treated with ND(PXL) showed no significant changes in behavioral responses or toxicity score. Our ND formulation was designed to be readily adaptable to incorporate different drugs, imaging modalities and/or targeting motifs. This formulation has significant potential for preclinical and clinical tools across multiple disease states. The studies presented here report a novel toxicity score for assessing peripheral neuropathy and demonstrate that our targeted, theranostic NDs are safe and effective, providing localized tumor delivery of a chemotherapeutic and with reduced common neurotoxic side-effects.

Overexpression of cytoplasmic β-catenin inhibits the metastasis of the murine osteosarcoma cell line LM8

Background

Previously, we found that treatment of LM8 murine osteosarcoma cells with genistein, an isoflavone found in soy, increased the cellular level of β-catenin and decreased its invasive and motile potential. The purpose of this study is to investigate whether the expression of β-catenin in LM8 cells is associated with metastatic potential in nude mice. To this end, we used untreated and genistein-treated LM8 cells.

Methods

LM8 cells were treated for 3 days with or without 50 μM genistein and harvested by trypsinization. Untreated (the control group) and genistein-treated (the genistein group) cells were subcutaneously inoculated into the backs of male nude mice. After 25 days of inoculation, the tumors, lungs, and livers were excised, fixed in 10% formalin, and embedded in paraffin. The sections of formalin-fixed, paraffin-embedded lungs and livers were stained with hematoxylin-eosin (H&E) to confirm the absence or presence of metastatic tumors. The expression of β-catenin within the primary tumor was immunohistochemically examined.

Results

All mice in the control group (n = 8) exhibited large primary tumors, while in the genistein group (n = 8), one mouse showed no tumor formation and the remaining seven mice exhibited smaller primary tumors compared with the control group. The tumor mass of the genistein group was 23% of that of the control group. In the control group, multiple metastatic tumors were found in the lung and/or liver and the metastatic incidence was 100% in the lung and 87.5% in the liver. Six of seven tumor-bearing mice in the genistein group developed no metastatic tumors in the lung or liver, and this group was termed the genistein/metastasis(-) subgroup. Positive β-catenin immunostaining was observed in the cytoplasm of tumor cells, and the β-catenin-labeling index was higher in the genistein/metastasis(-) subgroup than in the control group. The intensity of cytoplasmic β-catenin immunostaining was stronger in the genistein/metastasis(-) subgroup compared with the control group, and the β-catenin-labeling score was 1.9-times higher in the former subgroup than in the latter group.

Conclusions

Overexpression of cytoplasmic β-catenin in LM8 cells causes inhibition of the growth of primary tumors and loss of the metastatic potential to the lung and liver.

Evaluation of MMP2 and Caspase-3 expression in 107 cases of papillary thyroid carcinoma and its association with prognostic factors

Papillary thyroid carcinoma (PTC), including its variants and widely varying behavior, constitutes about 80% of all thyroid malignancies. Increased knowledge regarding molecular alterations has led to attempts to identify diagnostic or prognostic factors for a reliable preoperative approach to the classification of patients according to risk of recurrence. In this study, 107 cases of PTC with known histological properties, including vascular or capsular invasion, were assessed for expression of MMP2 and Caspase-3 using immunohistochemistry. Considering 10% as a cutoff to discriminate cases with invasive behavior from the non-invasive group, there was no relationship between expression of MMP2 or Caspase-3 in tumor cells and the presence of capsular invasion (p=0.45 and 0.64, respectively), as well as for the expression of Caspase-3 and vascular invasion (p=0.43). In case of MMP2, a borderline correlation was found between the positive reaction of tumor cells with the presence of vascular invasion (p=0.05). So the evaluation of MMP2 in thyroid PTC appears to be of some benefit to the prediction of tumor behavior while Caspase-3 as a marker of prediction seems to be of no use.

Targeting of colorectal cancer growth, metastasis, and anti-apoptosis in BALB/c nude mice via APRIL siRNA

A proliferation-inducing ligand (APRIL) is overexpressed in most tumor cells and tissues, especially in tumors of the alimentary system, such as colorectal cancer (CRC), gastric cancer, and liver cancer. RNA interference (RNAi) has been proved to be a powerful tool for gene knockdown and holds great promise for the treatment of cancer. In this study, the efficacy of RNAi targeting APRIL was analyzed via relevant experiments on human CRC xenografted in BALB/c nude mice. Both the mRNA and protein levels of APRIL were examined after intratumoral injection of APRIL small interfering RNA (siRNA). Meanwhile, pathological tools were utilized to observe the alterations on the aspects of proliferation, metastasis, apoptosis and cellular necrosis by means of detecting proliferating cell nuclear antigen, Ki-67, MMP-2, MMP-9, TIMP-3, TIMP-4, Bcl-2, Bax and Bcl-xL of CRC. In addition, terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labeling (TUNEL) and hematoxylin and eosin staining were also conducted to examine cell apoptosis and necrosis. It was found that grafted human colorectal tumor growth and metastasis were obviously inhibited while tumor cell apoptosis and necrosis were induced after in vivo APRIL siRNA injection into nude mice. The data indicated that silencing of the APRIL gene using RNAi may serve as a novel therapeutic strategy for treatment of CRC.

The role of the microenvironment in tumor growth and invasion

Mathematical modeling and computational analysis are essential for understanding the dynamics of the complex gene networks that control normal development and homeostasis, and can help to understand how circumvention of that control leads to abnormal outcomes such as cancer. Our objectives here are to discuss the different mechanisms by which the local biochemical and mechanical microenvironment, which is comprised of various signaling molecules, cell types and the extracellular matrix (ECM), affects the progression of potentially-cancerous cells, and to present new results on two aspects of these effects. We first deal with the major processes involved in the progression from a normal cell to a cancerous cell at a level accessible to a general scientific readership, and we then outline a number of mathematical and computational issues that arise in cancer modeling. In Section 2 we present results from a model that deals with the effects of the mechanical properties of the environment on tumor growth, and in Section 3 we report results from a model of the signaling pathways and the tumor microenvironment (TME), and how their interactions affect the development of breast cancer. The results emphasize anew the complexities of the interactions within the TME and their effect on tumor growth, and show that tumor progression is not solely determined by the presence of a clone of mutated immortal cells, but rather that it can be 'community-controlled'.

Synergistic effect of stromelysin-1 (matrix metalloproteinase-3) promoter (-1171 5A->6A) polymorphism in oral submucous fibrosis and head and neck lesions

BACKGROUND

Matrix metalloproteinases (MMPs) are enzymes that degrade all the components of extra cellular matrix and collagen. Various types of MMPs are known to be expressed and activated in patients with oral submucous fibrosis (OSMF) as well as head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to asses the association of the single nucleotide polymorphism (SNP) adenosine insertion/deletion polymorphism (-1171 5A->6A) in the MMP-3 promoter region in these lesions.

METHODS

MMP-3 SNP was genotyped by polymerase chain reaction-restriction fragment polymorphism (PCR-RFLP) analysis in a case control study consisting of 362 participants; 101 cases of OSMF, 135 of HNSCC and 126 controls, compared for age, sex and habits. ROC distribution was plotted to assess the contributions of genetic variation in MMP-3 genotypes with relation to age.

RESULTS

Analysis of MMP 3 (-1171 5A->6A) polymorphism revealed the frequency of 5A allele in OSMF, HNSCC and controls to be 0.15, 0.13 and 0.07, respectively. A significant difference was found in 5A genotype frequency between OSMF (5A genotype frequency = 0.15, p = 0.01, OR = 2.26, 95% CI = 1.22-4.20) and in controls (5A genotype frequency 0.07) as well as HNSCC (5A genotype frequency 0.13, p = 0.03,95%CI = 1.06-3.51) and controls (5A genotype frequency = 0.07) In this study, 5A genotype had greater than two fold risk for developing OSMF (OR = 2.26) and nearly the same in case of HNSCC (OR = 1.94) as compared to controls. In patients with OSMF as well as HNSCC, the ROC analysis between the MMP-3 genotype and age, 6A/6A allele was found to be significant in patients both over and under 45 years of age; while the 5A/5A carrier alleles showed an association only in patients less than 45 years of age.

CONCLUSIONS

This study concluded that the expression of MMP-3 genotype associated with the 5A alleles, it may have an important role in the susceptibility of the patients to develop OSMF and HNSCC.

Matrix metalloproteinase-induced epithelial-mesenchymal transition in breast cancer

Matrix metalloproteinases (MMPs) degrade and modify the extracellular matrix (ECM) as well as cell-ECM and cell-cell contacts, facilitating detachment of epithelial cells from the surrounding tissue. MMPs play key functions in embryonic development and mammary gland branching morphogenesis, but they are also upregulated in breast cancer, where they stimulate tumorigenesis, cancer cell invasion and metastasis. MMPs have been investigated as potential targets for cancer therapy, but clinical trials using broad-spectrum MMP inhibitors yielded disappointing results, due in part to lack of specificity toward individual MMPs and specific stages of tumor development. Epithelial-mesenchymal transition (EMT) is a developmental process in which epithelial cells take on the characteristics of invasive mesenchymal cells, and activation of EMT has been implicated in tumor progression. Recent findings have implicated MMPs as promoters and mediators of developmental and pathogenic EMT processes in the breast. In this review, we will summarize recent studies showing how MMPs activate EMT in mammary gland development and in breast cancer, and how MMPs mediate breast cancer cell motility, invasion, and EMT-driven breast cancer progression. We also suggest approaches to inhibit these MMP-mediated malignant processes for therapeutic benefit.

Effect of troglitazone on tumor growth and pulmonary metastasis development of the mouse osteosarcoma cell line LM8

Background

Osteosarcoma often develops micrometastases in the lung prior to diagnosis, causing a fatal outcome. Therefore, the prevention of pulmonary metastases is critical for the improvement of the prognosis of patients with osteosarcoma. The purpose of this study was to investigate whether troglitazone (TGZ) is considered as possible therapeutics in the treatment of growth and metastasis of osteosarcoma.

Methods

LM8 cells were treated for 3 days with various concentrations of TGZ. The effect of TGZ on cell proliferation was determined by DNA measurement in the cultures and 5-bromo-2'-deoxyuridine incorporation study. The assay of cell invasion and motility was performed using either the Matrigel-coated cell culture inserts or the uncoated cell culture inserts in the invasion chambers. The effect of TGZ on Akt signaling was assessed by Western blot analysis of Akt and p-Akt. The effects of oral administration of either TGZ (TGZ group) or ethanol (control group) on the growth of primary tumor and the development of pulmonary metastasis were examined in nude mice implanted with LM8 cells on their backs. The expression and activity of matrix metalloproteinase 2 (MMP-2) within the tumor were determined by immunohistochemistry and zymography. The microvessel density (MVD) within the tumor was determined by immunohistochemistry for CD34.

Results

TGZ dose-dependently inhibits cell proliferation. TGZ-treated cells were less invasive and less motile than untreated cells. The activity of MMP-2 secreted by TGZ-treated cells was lower than that secreted by untreated cells. TGZ decreased the level of p-Akt. The primary tumor mass was smaller in the TGZ group than in the control group. The TGZ group had less metastatic tumors in the lung compared with the control group. The expression and activity of MMP-2 within the tumor of the TGZ group were lower than those of the control group. The MVD within the tumor of the TGZ group was lower than that of the control group.

Conclusions

Inhibition of Akt signaling by TGZ may decrease the secretion of MMP-2, resulting in the decrease of invasiveness and motility in LM8 cells. Treatment of tumor-bearing mice with TGZ decreases the expression and activity of MMP-2 within the tumor, and inhibits primary tumor growth and pulmonary metastasis development. TGZ may offer a new approach in chemotherapy for osteosarcoma.

Ketoprofen in topical formulation decreases the matrix metalloproteinase-2 expression and pulmonary metastatic incidence in nude mice with osteosarcoma

The aim of this study was to investigate whether ketoprofen (KP) in topical formulation affected the tumor growth and pulmonary metastasis of LM8 cells, which were inoculated subcutaneously into the back space of male nude mice. At 7 days after inoculation, the tumor was treated topically for 3 weeks with either a KP-containing patch (KP group) or a placebo-containing patch (placebo group). The pulmonary metastatic incidence was 100% in the placebo group and 60% in the KP group. The tumor mass of the KP group without pulmonary metastasis, termed the KP/metastasis(-) group, was smaller than that of the placebo group. Immunohistochemical staining for proliferating cell nuclear antigen (PCNA), terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), matrix metalloproteinase-2 (MMP-2), and vascular endothelial growth factor (VEGF) was performed. The tumors of the KP/metastasis(-) group contained fewer PCNA-positive cells and many more TUNEL-positive cells in comparison to the placebo group. In the placebo group, MMP-2 and VEGF were extensively expressed within the tumor, whereas in the KP/metastasis(-) group the expression of these two proteins was very low. In conclusion, the topical treatment of osteosarcoma with KP decreased the expression of MMP-2 and VEGF, thus resulting in the suppression of tumor growth and pulmonary metastasis.

Delineating protease functions during cancer development

Much progress has been made in understanding how matrix remodeling proteases, including metalloproteinases, serine proteases, and cysteine cathepsins, functionally contribute to cancer development. In addition to modulating extracellular matrix metabolism, proteases provide a significant protumor advantage to developing neoplasms through their ability to modulate bioavailability of growth and proangiogenic factors, regulation of bioactive chemokines and cytokines, and processing of cell-cell and cell-matrix adhesion molecules. Although some proteases directly regulate these events, it is now evident that some proteases indirectly contribute to cancer development by regulating posttranslational activation of latent zymogens that then directly impart regulatory information. Thus, many proteases act in a cascade-like manner and exert their functionality as part of a proteolytic pathway rather than simply functioning individually. Delineating the cascade of enzymatic activities contributing to overall proteolysis during carcinogenesis may identify rate-limiting steps or pathways that can be targeted with anti-cancer therapeutics. This chapter highlights recent insights into the complexity of roles played by pericellular and intracellular proteases by examining mechanistic studies as well as the roles of individual protease gene functions in various organ-specific mouse models of cancer development, with an emphasis on intersecting proteolytic activities that amplify programming of tissues to foster neoplastic development.

Differential expression of matrix metalloproteinase (MMP)-2, MMP-9 and tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in non-melanoma skin cancer: implications for tumour progression

AIMS

To investigate the expression of matrix metalloproteinase (MMP)-2, MMP-9, and tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 in non-melanoma skin cancer (NMSC) and to compare their expression between different tumour types and with clinicopathological factors.

METHODS AND RESULTS

A study of 11 normal skin, 29 Bowen's disease (BD), 40 squamous cell carcinoma (SCC) and 38 basal cell carcinoma (BCC) samples for MMP-2, MMP-9, TIMP-1 and TIMP-2 expression was carried out using immunohistochemistry and in situ hybridization. The expression of all metalloproteinases was greater in tumours than in normal skin. MMP-2 and MMP-9 expression was more extensive in the stroma of SCC than of BCC or BD. TIMP-1 expression was greater in the stroma of BCC than of SCC or BD and TIMP-2 expression was greater in the stroma of SCC than of BD. There was a correlation between increased metalloproteinase expression and depth of lesion (MMP-2 and TIMP-2), inflammation (MMP-2, MMP-9, TIMP-1 and TIMP-2) and microvessel density (MMP-2, MMP-9 and TIMP-2).

CONCLUSIONS

MMP-2, MMP-9, TIMP-1 and TIMP-2 play an important role in the pathogenesis of non-melanoma skin cancer, but differ significantly in their expression levels between the tumour types examined. The immunoexpression of these proteins may be useful indicators of cutaneous cancer invasion and progression.

Extracellular proteolysis in transgenic mouse models of breast cancer

Growth and invasion of breast cancer require extracellular proteolysis in order to physically restructure the tissue microenvironment of the mammary gland. This pathological tissue remodeling process depends on a collaboration of epithelial and stromal cells. In fact, the majority of extracellular proteases are provided by stromal cells rather than cancer cells. This distinct expression pattern is seen in human breast cancers and also in transgenic mouse models of breast cancer. The similar expression patterns suggest that transgenic mouse models are ideally suited to study the role of extracellular proteases in cancer progression. Here we give a status report on protease intervention studies in transgenic models. These studies demonstrate that proteases are involved in all stages of breast cancer progression from carcinogenesis to metastasis. Transgenic models are now beginning to provide vital mechanistic insight that will allow us to combat breast cancer invasion and metastasis with new protease-targeted drugs.

Smad4-dependent Regulation of Urokinase Plasminogen Activator Secretion and RNA Stability Associated with Invasiveness by Autocrine and Paracrine Transforming Growth Factor-β

Metastasis is a primary cause of mortality due to cancer. Early metastatic growth involves both a remodeling of the extracellular matrix surrounding tumors and invasion of tumors across the basement membrane. Up-regulation of extracellular matrix degrading proteases such as urokinase plasminogen activator (uPA) and matrix metalloproteinases has been reported to facilitate tumor cell invasion. Autocrine transforming growth factor-beta (TGF-beta) signaling may play an important role in cancer cell invasion and metastasis; however, the underlying mechanisms remain unclear. In the present study, we report that autocrine TGF-beta supports cancer cell invasion by maintaining uPA levels through protein secretion. Interestingly, treatment of paracrine/exogenous TGF-beta at higher concentrations than autocrine TGF-beta further enhanced uPA expression and cell invasion. The enhanced uPA expression by exogenous TGF-beta is a result of increased uPA mRNA expression due to RNA stabilization. We observed that both autocrine and paracrine TGF-beta-mediated regulation of uPA levels was lost upon depletion of Smad4 protein by RNA interference. Thus, through the Smad pathway, autocrine TGF-beta maintains uPA expression through facilitated protein secretion, thereby supporting tumor cell invasiveness, whereas exogenous TGF-beta further enhances uPA expression through mRNA stabilization leading to even greater invasiveness of the cancer cells.

Matrix metalloproteinases play an active role in Wnt1-induced mammary tumorigenesis

The Wnt signaling transduction pathway plays a critical role in the pathogenesis of several murine and human epithelial cancers. Here, we have used mouse mammary tumor virus (MMTV)-Wnt1 transgenic mice, which develop spontaneous mammary adenocarcinoma, to examine whether matrix metalloproteinases (MMPs)--a family of extracellular proteases implicated in multiple steps of cancer progression--contributed to Wnt1-induced tumorigenesis. An analysis of the expression of several MMPs by RT-PCR and in situ hybridization revealed an increase in the expression of MMP-2, MMP-3, MMP-9, MMP-13, and MT1-MMP (MMP-14) in hyperplastic glands and in mammary tumors of MMTV-Wnt1 transgenic mice. Interestingly, whereas MMP-2, MMP-3, and MMP-9 were exclusively expressed by stromal cells in mammary tumors, MMP-13 and MT1-MMP were expressed by transformed epithelial cells in addition to the tumor stroma. To determine whether these MMPs contributed to tumorigenesis, MMTV-Wnt1 mice were crossed with transgenic mice overexpressing tissue inhibitor of metalloproteinase-2-a natural MMP inhibitor-in the mammary gland. In the double MMTV-Wnt1/tissue inhibitor of metalloproteinases-2 transgenic mice, we observed an increase in tumor latency and a 26.3% reduction in tumor formation. Furthermore, these tumors grew at a slower rate, exhibited an 18% decrease in proliferative rate, and a 12.2% increase in apoptotic rate of the tumor cells in association with a deficit in angiogenesis when compared with tumors from MMTV-Wnt1 mice. Thus, for the first time, the data provides evidence for the active role of MMPs in Wnt1-induced mammary tumorigenesis.

MMP-9 and MMP-2 gelatinases and TIMP-1 and TIMP-2 inhibitors in breast cancer: correlations with prognostic factors

The goal of our study was to analyse the prognostic values for some matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in breast cancer. We evaluated the activity and the expression levels of MMP-9, MMP-2, TIMP-1 and TIMP-2 in malignant versus benign fresh breast tumor extracts. For this purpose, gelatinzymography, immunoblotting and ELISA were used to analyse the activity and expression of MMPs and TIMPs. We found that MMP-9 expression level and activity are increased in malignant tumors. In addition, MMP-9/TIMP-1 and MMP-2/TIMP-2 ratio values obtained by us were significantly different in malignant tumors compared to benign tumors. We suggest that the abnormal MMP-9/TIMP-1 balance plays a role in the configuration of breast invasive carcinoma of no special type and also in tumor growth, while altered MMP-2/TIMP-2 ratio value could be associated with lymph node invasion and used as a prognostic marker in correlation with Nottingham Prognostic Index. Finally, we showed that in malignant tumors high expression of estrogen receptors is associated with enhanced activity of MMP-2 and increased bcl- 2 levels, while high expression of progesterone receptors is correlated with low TIMP-1 protein levels.

Dentin matrix protein 1 enhances invasion potential of colon cancer cells by bridging matrix metalloproteinase-9 to integrins and CD44

The up-regulation of various matrix metalloproteinases (MMP), certain cell receptors such as integrins and CD44, and the SIBLING family of integrin-binding glycophosphoproteins have been reported separately and in various combinations for many types of tumors. The mechanisms by which these different proteins may be interacting and enhancing the ability of a cancer cell to survive and metastasize have become an interesting issue in cancer biology. Dentin matrix protein 1 (DMP1) has been known for a number of years to bind to CD44 and ArgGlyAsp sequence-dependent integrins. This SIBLING was recently shown to be able to specifically bind and activate proMMP-9 and to make MMP-9 much less sensitive to inhibition by tissue inhibitors of metalloproteinases and synthetic inhibitors. In this study, we used a modified Boyden chamber assay to show that DMP1 enhanced the invasiveness of the MMP-9 expressing colon cancer cell line, SW480, through Matrigel in a dose-dependant manner. DMP1 (100 nmol/L) increased invasion 4-fold over controls (86.1 +/- 13.9 versus 22.3 +/- 9.8, P < 0.001). The enhanced invasive potential required the presence of MMP-9 and at least one of the cell surface receptors, CD44, alpha(v)beta(3), or alpha(v)beta(5) integrin. The bridging of MMP-9 to the cell surface receptors was shown by both pull-down and fluorescence activated cell sorting experiments. Because all of these proteins were also shown by immunohistochemistry to be expressed in serial sections of a colon adenocarcinoma, we have hypothesized that the MMP-9/DMP1/cell surface complexes observed to enhance cell invasion in vitro may be aiding metastatic events in vivo.

Matrix metalloproteinases in the process of invasion and metastasis of breast cancer

Metastatic cascade in malignant tumors, including breast cancer, starts with localized invasion of the host tissue. This process, requiring that tumor cells separate from each other, includes loss of homotypic and heterotypic cell adhesion and cell-cell contact inhibition, acquisition of motility, exacerbated by "epithelial-to-mesenchymal transition", and production of proteolytic enzymes which degrade basal membrane and extracellular matrix. In this sense, aside from urokinase type plasminogen activator, increased expression and activity of matrix metalloproteinases (MMPs) is one of the earliest and most sustained events in tumor progression, playing a role in angiogenesis, invasion and metastasis. MMPs are a family of 23 zinc metalloproteinases, secreted as latent pro-enzymes, activated by proteolytic cleavage, and inhibited by the tissue inhibitors of metalloproteinases. The most commonly connected MMPs with the processes of metastasis are MMP-2 (gelatinase A) and MMP-9 (gelatinase B), due to their ability to degrade collagen type IV, major component of vascular basement membrane. MMP-2 and MMP-9 are also required for the switch to the "angiogenic phenotype" during tumor progression and activation of dormant tumor cells. The association of the increase in serum MMP-2 and MMP-9 activity and clinical stage suggests the usefulness of these parameters as markers in the follow-up and prognosis of breast cancer patients. The concept of "stromal-directed therapy" of cancer, with MMP-inhibitors directed against MMPs as targets, is based on the observed MMP up-regulation in tumors.

Downregulation of human kallikrein 10 (KLK10/NES1) by CpG island hypermethylation in breast, ovarian and prostate cancers

OBJECTIVE

The human kallikrein 10 (KLK10)/normal epithelial cell-specific-1 (NES1) gene is highly expressed in normal mammary, ovary and prostate cells, but its expression is dramatically decreased in cancer cell lines. Recently, it has been shown that CpG island hypermethylation of the KLK10 gene is responsible for the tumor-specific loss of KLK10 gene expression in certain breast cancer cell lines.

METHOD

We examined the role of CpG island hypermethylation in the tumor-specific loss of KLK10 expression in breast, ovarian and prostate cancers. We treated cells with the demethylating agent 5-aza-2'-deoxycytidine (dC) and monitored changes in KLK10 mRNA by RT-PCR and secreted hK10 protein expression by ELISA. The following cell lines were used: MDA-MB-231, MDA-MB-468, MCF-7, ZR-75-1, T-47D and BT-474 (breast); BG-1, MDAH-2774, HTB-75, HTB-161, PA-1 and ES-2 (ovary), and LNCaP and PC-3 (prostate).

RESULTS

Upregulation of KLK10 mRNA levels, which was accompanied by an increase in secreted hK10 protein concentration, was observed for a subset of breast, ovarian, and prostate tumor cell lines after 5-aza-2'-dC. Genomic sequencing of sodium-bisulfite-treated DNA demonstrated that CpG sites within the KLK10 gene exon 3 were highly methylated. Hypermethylation of exon 3 CpG regions was also detected in primary ovarian cancers.

CONCLUSION

These data suggest that CpG island hypermethylation plays an important role in the downregulation of kallikrein 10 mRNA and protein expression, but it cannot explain the pattern of expression of this gene in all cell lines or tissue tested.

Localization of a mutant p53 response element on the tissue inhibitor of metalloproteinase-3 promoter: mutant p53 activities are distinct from wild-type

Missense mutations in the p53 gene have been observed in greater than 60% of all human tumors. Recent evidence indicates that some mutations in p53 arise as the cancer progresses from a benign tumor to a metastatic tumor and that these mutations in p53 actively contribute to the process of cancer progression. Previously, we reported that the expression of the gene encoding the tissue inhibitor of metalloproteinase-3 (TIMP-3) is repressed in cells expressing codons 248 and 281 mutant p53 alleles. The ability of tumor-derived p53 mutants to inhibit TIMP-3 expression provides a novel mechanism for understanding how p53 mutations might contribute to tumorigenesis. Since mutant p53 is often expressed at elevated levels in a variety of cancers, the generation of cells in a tumor carrying certain mutations in p53 would cause inappropriately reduced expression of TIMP-3 and lead to elevated matrix metalloproteinase activity. We present the results of experiments that begin to determine the mechanism by which mutant p53 represses TIMP-3 gene expression. By generating deletion derivatives of the TIMP-3 promoter and testing them for expression and by performing DNA protein binding assays on the regions determined to be required for repression, we have identified elements that are essential for mutant p53-mediated transcriptional repression. These elements respond specifically to mutant but not wild type p53. While mutant p53 itself does not bind to the TIMP-3 promoter, we provide evidence for the presence of DNA binding proteins whose activity is enhanced in the presence of mutant p53.

Deregulated matriptase causes ras-independent multistage carcinogenesis and promotes ras-mediated malignant transformation

Overexpression of the type II transmembrane serine protease matriptase is a highly consistent feature of human epithelial tumors. Here we show that matriptase possesses a strong oncogenic potential when unopposed by its endogenous inhibitor, HAI-1. Modest orthotopic overexpression of matriptase in the skin of transgenic mice caused spontaneous squamous cell carcinoma and dramatically potentiated carcinogen-induced tumor formation. Matriptase-induced malignant conversion was preceded by progressive interfollicular hyperplasia, dysplasia, follicular transdifferentiation, fibrosis, and dermal inflammation. Furthermore, matriptase induced activation of the pro-tumorigenic PI3K-Akt signaling pathway. This activation was frequently accompanied by H-ras or K-ras mutations in carcinogen-induced tumors, whereas matriptase-induced spontaneous carcinoma formation occurred independently of ras activation. Increasing epidermal HAI-1 expression completely negated the oncogenic effects of matriptase. The data implicate dysregulated matriptase expression in malignant epithelial transformation.

Clinical significance of human kallikrein gene 6 messenger RNA expression in colorectal cancer

PURPOSE

Human kallikrein gene 6 (KLK6) is a member of the human kallikrein gene family, and recent studies have found that many kallikreins have altered expression patterns in various malignancies. The purpose of the current study was to quantify the expression of KLK6 in malignant and benign colorectal tissues and to statistically analyze whether KLK6 expression levels correlate with clinicopathologic variables and prognosis in patients with colorectal cancer.

EXPERIMENTAL DESIGNS

Paired colorectal tissue samples from cancerous and corresponding noncancerous tissues were obtained from 63 patients with colorectal cancer who underwent surgical resection. Quantitative analyses of KLK6 mRNA expression were done using real-time quantitative reverse transcription-PCR.

RESULTS

KLK6 mRNA overexpression in cancerous tissues compared with normal counterparts was observed in 57 of 63 (90%) patients. The mean expression level of KLK6 mRNA in cancerous tissues was significantly higher than that in noncancerous tissues (P < 0.0001). Elevated KLK6 expression was significantly correlated with serosal invasion (P < 0.05), liver metastasis (P < 0.05), and advanced Duke's stage (P < 0.01). Furthermore, patients with high KLK6 expression had a significantly poorer actuarial overall survival than patients with low KLK6 expression (5-year overall survival rates: 54% and 73%, respectively, P < 0.05).

CONCLUSIONS

The results of this study indicated that KLK6 mRNA expression was significantly higher in cancerous than in noncancerous colorectal tissues, and high expression of KLK6 mRNA correlated with serosal invasion, liver metastasis, advanced Duke's stage, and a poor prognosis for patients with colorectal cancer.

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.

The tension mounts: mechanics meets morphogenesis and malignancy

The tissue microenvironment regulates mammary gland development and tissue homeostasis through soluble, insoluble and cellular cues that operate within the three dimensional architecture of the gland. Disruption of these critical cues and loss of tissue architecture characterize breast tumors. The developing and lactating mammary gland are also subject to a plethora of tensional forces that shape the morphology of the gland and orchestrate its functionally differentiated state. Moreover, malignant transformation of the breast is associated with dramatic changes in gland tension that include elevated compression forces, high tensional resistance stresses and increased extracellular matrix stiffness. Chronically increased mammary gland tension may influence tumor growth, perturb tissue morphogenesis, facilitate tumor invasion, and alter tumor survival and treatment responsiveness. Because mammary tissue differentiation is compromised by high mechanical force and transformed cells exhibit altered mechanoresponsiveness, malignant transformation of the breast may be functionally linked to perturbed tensional-homeostasis. Accordingly, it will be important to define the role of tensional force in mammary gland development and tumorigenesis. Additionally, it will be critical to identify the key molecular elements regulating tensional-homeostasis of the mammary gland and thereafter to characterize their associated mechanotransduction pathways.

Characterisation of human kallikrein 6/protease M expression in ovarian cancer

Kallikrein 6 (hK6, also known as protease M/zyme/neurosin) is a member of the human kallikrein gene family. We have previously cloned the cDNA for this gene by differential display and shown the overexpression of the mRNA in breast and ovarian primary tumour tissues and cell lines. To thoroughly characterise the expression of this kallikrein in ovarian cancer, we have developed a novel monoclonal antibody specific to hK6 and employed it in immunohistochemistry with a wide range of ovarian tumour samples. The expression was found elevated in 67 of 80 cases of ovarian tumour samples and there was a significant difference in the expression levels between normal and benign ovarian tissues and the borderline and invasive tumours (P<0.001). There was no difference of expression level between different subtypes of tumours. More significantly, high level of kallikrein 6 expression was found in many early-stage and low-grade tumours, and elevated hK6 proteins were found in benign epithelia coexisting with borderline and invasive tissues, suggesting that overexpression of hK6 is an early phenomenon in the development of ovarian cancer. Quantitative real-time reverse transcription–polymerase chain reactions also showed elevated kallikrein 6 mRNA expression in ovarian tumours. Genomic Southern analysis of 19 ovarian tumour samples suggested that gene amplification is one mechanism for the overexpression of hK6 in ovarian cancer.

Bone Sialoprotein, Matrix Metalloproteinase 2, and v 3 Integrin in Osteotropic Cancer Cell Invasion

BACKGROUND

Bone sialoprotein (BSP) interacts separately with both matrix metalloproteinase 2 (MMP-2) and integrin alpha(v)beta3 and is overexpressed in many metastatic tumors. Its role in tumor biology, however, remains unclear. We investigated whether BSP enhances cancer cell invasiveness by forming a trimolecular complex with MMP-2 and cell-surface integrin alpha(v)beta3.

METHODS

Invasiveness of breast, prostate, lung, and thyroid tumor cell lines was measured with a modified Boyden chamber assay. Binding and co-localization of BSP, MMP-2, and integrin alpha(v)beta3 were investigated with immunoprecipitation and in situ hybridization. All statistical tests were two-sided.

RESULTS

Treatment with BSP increased invasiveness of many breast, prostate, lung, and thyroid cancer cells through Matrigel in a dose-dependent manner. BSP at 50 nM increased the invasiveness of SW-579 thyroid cancer cells (95.2 units, 95% confidence interval [CI] = 90.4 to 100 units) by approximately 10-fold compared with that of untreated control SW-579 cells (9.1 units, 95% CI = 5.7 to 12.5 units) (P<.001). Addition of an inactive mutated BSP, in which BSP's integrin-binding RGD tripeptide was altered, or addition of integrin alpha(v)beta3-blocking antibodies resulted in invasiveness equivalent to that of untreated cells. Inhibiting cellular MMP-2 activity with chemical inhibitors or a specific antibody also blocked BSP-enhanced invasiveness. Osteopontin and dentin matrix protein 1, proteins related to BSP that also bind integrin alpha(v)beta3 and form complexes with other MMPs (but not MMP-2), did not enhance invasiveness. Immunoprecipitation showed that a complex containing BSP, integrin alpha(v)beta3, and MMP-2 formed in vitro. Addition of BSP increased the amount of MMP-2 bound by cells in an integrin-dependent fashion. Co-expression of BSP, integrin alpha(v)beta3, and MMP-2 in papillary thyroid carcinoma cells was shown by in situ hybridization.

CONCLUSION

Cancer cells appear to become more invasive when BSP forms a cell-surface trimolecular complex by linking MMP-2 to integrin alpha(v)beta3.

The Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8) K1 protein induces expression of angiogenic and invasion factors

Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8) has been linked to Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. In addition to endothelial cells and B lymphocytes, KSHV also has been shown to infect epithelial cells and keratinocytes. The transmembrane glycoprotein K1, encoded by the first open reading frame of KSHV, is a signaling protein capable of eliciting B-cell activation. We show that KSHV K1 can induce expression and secretion of vascular endothelial growth factor (VEGF) in epithelial and endothelial cells. Up-regulation of VEGF was mediated at the transcriptional level because expression of K1 resulted in VEGF promoter activation. We also show that K1 induces expression of matrix metalloproteinase-9 (MMP-9) in endothelial cells. Additional analyses with K1 mutant proteins revealed that the SH2 binding motifs present in the K1 cytoplasmic tail are necessary for VEGF secretion and MMP-9 induction. These results indicate that K1 signaling may contribute to KSHV-associated pathogenesis through a paracrine mechanism by promoting the secretion of VEGF and MMP-9 into the surrounding matrix.

Expression of matrix metalloproteinases in feline vaccine site-associated sarcomas

OBJECTIVES

To screen for expression of 9 predominant members of the matrix metalloproteinase (MMP) family, including membrane-type matrix metalloproteinases (MT-MMPs) and tissue inhibitors of metalloproteinases (TIMPs), in primary tumor tissue biopsy specimens of vaccine site-associated sarcomas (VSS) in cats and compare expression profiles of VSS with expression profiles of non-VSS and carcinomas.

SAMPLE POPULATION

31 primary tumor tissue biopsy specimens and 6 nontumor (normal) tissue biopsy specimens.

PROCEDURES

Tissue specimens were obtained from primary tumor biopsy specimens of cats. Primers for reverse transcriptase-polymerase chain reaction assay were designed on the basis of known sequences. Data were analyzed for patterns of expression of MMPs, MT-MMPs, and TIMPs. Differences in expression patterns were evaluated among cats of differing genders, ages, metastasis status, and overall survival durations, and between cats with VSS and cats with non-VSS tumor types.

RESULTS

A total of 31 primary tumor tissue biopsy specimens and 6 nontumor (normal) tissue biopsy specimens were screened for the presence of 6 MMPs and 3 TIMPs. Matrix metalloproteinase and TIMP expression was found in non-VSS, carcinomas, and VSS. No significant differences were found in patterns of expression among tumor types. Metastasis was found to be the only predictive factor for overall survival duration. A significant correlation was found between MMP2 and MT-MMP16 expression and overall duration of survival.

CONCLUSIONS AND CLINICAL RELEVANCE

The identification of MMPs in feline VSS supports an underlying inflammatory pathogenesis for this tumor. Expression of MMP2 and MT-MMP16 were correlated with survival time in our study.

Isolation, characterization, and expression of feline stromelysin-1 in naturally developing tumors in cats

OBJECTIVE

To detect, isolate, and characterize feline stromelysin-1 (ie, matrix metalloproteinase [MMP]-3) in naturally developing tumors in cats.

SAMPLE POPULATION

31 tissue samples obtained from primary tumors and 6 samples of normal tissues from cats.

PROCEDURE

Biopsy specimens were obtained from primary tumors. Primers were designed on the basis of known sequences. The sequence of stromelysin-1 was cloned and analyzed. An additional primer set was used as a screening tool. Samples were assayed in duplicate or triplicate, when possible. Data obtained were analyzed for differences in expression of stromelysin-1 with regard to overall survival among cats of various sex, age, and disease status.

RESULTS

A 1,181-bp cDNA nucleotide sequence was amplified. The open reading frame encoded 393 amino acids. This amino acid sequence shared 70% to 85% sequence homology with sequences of other species. In addition, samples were screened for stromelysin-1. Of the 31 tumor samples tested, 16 (51.6%) had positive results for expression of stromelysin-1. Total RNA expression was detected in a diverse group of tumor types. Prognostic factors associated with a shorter duration of survival included evidence of metastasis and metastasis associated with expression of stromelysin-1.

CONCLUSIONS AND CLINICAL RELEVANCE

Feline stromelysin-1 contains all the conserved regions typically found in members of the MMP family. Activity of stromelysin-1 has been implicated in a wide number of physiologic and pathologic processes. Identification of this gene may lead to the development of useful reagents to assist with diagnosis and management of neoplastic diseases in cats.

Loss of surface and cyst epithelial basement membranes and preneoplastic morphologic changes in prophylactic oophorectomies

BACKGROUND

The authors suggested that the loss of collagen IV and laminin-containing basement membrane and the loss of Disabled-2 (Dab2) expression were two critical events associated with morphologic dysplastic changes of the ovarian surface epithelium as a step in tumorigenicity. Both the basement membrane and Dab2, a candidate tumor suppressor of ovarian carcinoma, were involved in epithelial cell surface positioning and organization. The authors speculated that the purging of the basement membrane may be similar to the proteolysis during gonadotropin-stimulated ovulation, a cyclooxygenase 2 (Cox-2)-mediated process.

METHODS

Prophylactic oophorectomy is used to prevent breast and ovarian carcinoma in high-risk populations. These ovarian tissue specimens often contain an increased presence of morphologically abnormal lesions that are believed to be preneoplastic. The authors evaluated archived prophylactic oophorectomy specimens to verify whether the loss of Dab2 expression and the removal of the basement membrane that occur at the ovarian surface and inclusion cyst epithelia are molecular markers of preneoplastic lesions. Of the 36 samples containing identifiable ovarian surface epithelial components on slides, immunostaining was employed to evaluate the intactness of the basement membrane (periodic acid-Schiff [PAS], collagen IV, and laminin) and the expression of Dab2 and Cox-2. Expression of Cox-1 and Cox-2 also were evaluated in cultured ovarian surface epithelial cells prepared from ovarian tissue specimens removed from patients who underwent prophylactic surgery.

RESULTS

The morphologically normal ovarian surface epithelium typically contained a collagen IV- and laminin-positive basement membrane, which also was detected by PAS staining. Many morphologically altered areas, such as papillomatosis, invaginations, inclusion cysts, stratification, adenomas, and microscopic adenocarcinomas, were found in these specimens. Both the morphologically altered and adjacent morphologically normal epithelia consistently exhibited loss of basement membrane and/or Dab2 expression and an increase in Cox-2 staining. Frequently, an increase in Cox-2 staining was correlated with the loss of epithelial basement membrane in morphologically normal areas.

CONCLUSIONS

The loss of Dab2 and basement membrane and the overexpression of Cox-2 were observed in presumptive neoplastic precursor areas of oophorectomy specimens obtained from a population at high risk for ovarian carcinoma. Transient loss of collagen IV and laminin in the basement membrane of the preneoplastic epithelium and the loss of Dab2 expression are common early events associated with morphologic alteration and tumorigenicity of the ovarian surface epithelium. The authors concluded that Cox-2 overexpression may play a role in the purging of basement membrane of the ovarian surface epithelium, mimicking the process of ovulation. Further experiments may be able to test the hypothetical model derived from these histologic observations.

Expression levels of vascular endothelial growth factor, matrix metalloproteinases 2 and 9 and tissue inhibitor of metalloproteinases 1 and 2 in the plasma of patients with ovarian carcinoma

We measured the levels of the vascular endothelial growth factor (VEGF), matrix metalloproteinases type 2 and type 9 (MMP-2 and MMP-9) and tissue inhibitors of matrix metalloproteinase 1 and 2 (TIMP-1 and TIMP-2) in the plasma of patients with ovarian carcinoma (n=40), in other gynaecological pathologies (n=30) and in the plasma of healthy volunteers (n=26). MMP-2 and MMP-9 (pro and active forms) gelatinolytic activity was measured by zymography. Enzyme-linked immunosorbent assays (ELISA) were used to assay soluble VEGF and TIMPs. Preoperative plasma VEGF levels were significantly higher in patients with ovarian cancer than in healthy volunteers (P<0.0001) or patients with a benign gynaecological pathology (P<0.0001). The expression of pro-MMP-9 was higher in the plasma of ovarian cancer patients than in the plasma of women with non-malignant disease (P=0.01) or healthy women (P<0.0002). Pro-MMP-2 was detected in the plasma of ovarian cancer patients, but levels did not differ from those in non-malignant disease or healthy donor samples. Plasma TIMP-1 and TIMP-2 levels were significantly higher in patients with ovarian carcinomas than in healthy volunteers (P<0.0001 and P=0.006, respectively) or in the patients with a non-malignant pathology (P<0.0001 and P=0.002, respectively). Sub-group analysis showed that VEGF and pro-MMP-9 were higher in the plasma of patients with serous carcinomas than other histological types. Furthermore, plasma VEGF and pro-MMP-9 levels were higher in the plasma of cancer patients with thrombocytosis. Throughout the study, and in the univariate analysis, no correlation was found between the VEGF, MMP and TIMP levels. Only TIMP-1 was associated with a poor survival and mortality risk.

Metastasis of transgenic breast cancer in plasminogen activator inhibitor-1 gene-deficient mice

The plasminogen activator inhibitor-1 (PAI-1) blocks the activation of plasmin(ogen), an extracellular protease vital to cancer invasion. PAI-1 is like the corresponding plasminogen activator uPA (urokinase-type plasminogen activator) consistently expressed in human breast cancer. Paradoxically, high levels of PAI-1 as well as uPA are equally associated with poor prognosis in cancer patients. PAI-1 is thought to play a vital role for the controlled extracellular proteolysis during tumor neovascularization. We have studied the effect of PAI-1 deficiency in a transgenic mouse model of metastasizing breast cancer. In these tumors, the expression pattern of uPA and PAI-1 resembles that of human ductal breast cancer and plasminogen is required for efficient metastasis. In a cohort of 63 transgenic mice that were either PAI-1-deficient or wild-type sibling controls, primary tumor growth and vascular density were unaffected by PAI-1 status. PAI-1 deficiency also did not significantly affect the lung metastatic burden. These results agree with the virtual lack of spontaneous phenotype in PAI-1-deficient mice and humans and may reflect that the plasminogen activation reaction is not rate limiting for tumor vascularization and metastasis, or that there is a functional redundancy between PAI-1 and other inhibitors of the uPA/plasmin system, masking the effect of PAI-1 deficiency.

The basement membrane matrix in malignancy

Cancer is the second most common cause of death among Americans, although for several age groups it ranks first. Most of these deaths are not due to the primary tumour but rather to tumour cell metastases to distant organs. There are many steps that lead to metastasis, all of which are being studied with the goal of preventing these fatalities. Normally, cells attach to the extracellular matrix to maintain tissue integrity. During cancer progression, cells become more motile and acquire invasive qualities. Tumour cells move along blood and lymph vessels or invade into them to travel to distant sites. Then, the tumour cells must attach to the vessel wall, extravasate from the vessel, invade the new tissue, proliferate, and form a secondary tumour. Angiogenesis, the formation of new blood vessels, is critical to survival of these cells at the new site and is also important for primary tumour growth and spread. Tumour cell metastasis is a complex cascade of sequential steps, each of which is not yet fully understood. Progress has been made in identifying several key activators, one of which is the extracellular matrix. A major tumour promoter is the glycoprotein laminin, which is predominantly found in the extracellular matrix produced by endothelial and epithelial cells. This review will follow the metastatic process with particular attention to the effect of laminin on tumour cells.

Extracellular matrix remodelling: the role of matrix metalloproteinases

Matrix metalloproteinases (MMPs) are a growing family of metalloendopeptidases that cleave the protein components of the extracellular matrix and thereby play a central role in tissue remodelling. For many years following their discovery, MMPs were believed to function primarily as regulators of ECM composition and to facilitate cell migration simply by removing barriers such as collagen. It is becoming increasingly clear, however, that MMPs are implicated in the functional regulation of a host of non-ECM molecules that include growth factors and their receptors, cytokines and chemokines, adhesion receptors and cell surface proteoglycans, and a variety of enzymes. MMPs therefore play an important role in the control of cellular interactions with and response to their environment in conditions that promote tissue turnover, be they physiological, such as normal development, or pathological, such as inflammation and cancer. This review summarizes some of the recent discoveries that have shed new light on the role of MMPs in physiology and disease.

Human kallikrein 6 (hK6): a new potential serum biomarker for diagnosis and prognosis of ovarian carcinoma

PURPOSE

The discovery of new ovarian cancer biomarkers that are suitable for early disease diagnosis and prognosis may ultimately lead to improved patient management and outcomes.

PATIENTS AND METHODS

We measured, by immunoassay, human kallikrein 6 (hK6) concentration in serum of 97 apparently healthy women, 141 women with benign abdominal diseases, and 146 women with histologically proven primary ovarian carcinoma. We then calculated the diagnostic sensitivity and specificity of this test and examined the association of serum hK6 concentration with various clinicopathologic variables and patient survival.

RESULTS

Serum hK6 concentration between normal and benign disease patients was not different (mean, 2.9 and 3.1 micro g/L, respectively). However, hK6 in presurgical serum of ovarian cancer patients was highly elevated (mean, 6.8 micro g/L; P <.001). Serum hK6 decreased after surgery (to a mean of 3.9 micro g/L) in 68% of patients. The diagnostic sensitivity of serum hK6 at 90% and 95% specificity is 52% and 47%, respectively, in the whole patient population. For early stage disease (stage I or II), sensitivity is approximately 21% to 26%. When combined with CA-125, at 90% specificity, sensitivity increases to 72% (for all patients) and to 42% in stage I or II disease. Serum hK6 concentration correlates moderately with CA-125 and is higher in patients with late-stage, higher-grade disease and in patients with serous histotype. Preoperative serum hK6 concentration is a powerful predictor of disease-free and overall survival in both univariate and multivariate analyses.

CONCLUSIONS

Serum hK6 concentration seems to be a new biomarker for ovarian carcinoma and may have value for disease diagnosis and prognosis.

Immunofluorometric quantitation and histochemical localisation of kallikrein 6 protein in ovarian cancer tissue: a new independent unfavourable prognostic biomarker

Human kallikrein 6 protein is a newly discovered human kallikrein. We determined the amount of human kallikrein 6 in extracts of 182 ovarian tumours and correlated specific activity (ng hK6 mg(-1) total protein) with clinicopathological variables documented at the time of surgical excision and with outcome (progression free survival, overall survival) monitored over a median interval of 62 months. Thirty per cent of the tumours were positive for human kallikrein 6 (>35 ng hK6 mg(-1) total protein). Human kallikrein 6-specific immunohistochemical staining of four ovarian tissues that included benign, borderline and malignant lesions indicated a cytoplasmic location of human kallikrein 6 in tumour cells of epithelial origin, although the intensity of staining was variable. Tumour human kallikrein 6 (ng hK6 mg(-1) total protein) was higher in late stage disease, serous histotype, residual tumour >1 cm and suboptimal debulking (>1 cm) (P<0.05). Univariate analysis revealed that patients with tumour human kallikrein 6 positive specific activity were more likely to suffer progressive disease and to die (hazard ratio 1.71 (P=0.015) and 1.88 (P=0.022), respectively). Survival curves demonstrated the same (P=0.013 and 0.019, respectively). Multivariate analysis revealed that human kallikrein 6 positivity was retained as an independent prognostic variable in several subgroups of patients, namely those with (low) grade I and II tumours (hazard ratio progression free survival 4.3 (P=0.027) and overall survival 4.1 (P=0.023)) and those with optimal debulking (hazard ratio progression free survival 3.8 (P=0.019) and overall survival 5.6 (P=0.011)). We conclude that tumour kallikrein 6 protein levels have utility as an independent adverse prognostic marker in a subgroup of ovarian cancer patients with otherwise apparently good prognosis.

Angiogenesis, thrombospondin, and ductal carcinoma in situ of the breast

Angiogenesis, the growth of new vessels from existing vasculature, plays an essential role in tumour development. The process involves interaction between a variety of cells, growth factors, and components of the extracellular matrix, regulated by pro-angiogenic and anti-angiogenic factors. This review profiles these factors, outlines the available methods for measuring new vessel formation, and discusses the importance of angiogenesis in breast cancer, with emphasis on ductal carcinoma in situ.

Matriptase/MT-SP1 is required for postnatal survival, epidermal barrier function, hair follicle development, and thymic homeostasis

Matriptase/MT-SP1 is a novel tumor-associated type II transmembrane serine protease that is highly expressed in the epidermis, thymic stroma, and other epithelia. A null mutation was introduced into the Matriptase/MT-SP1 gene of mice to determine the role of Matriptase/MT-SP1 in epidermal development and neoplasia. Matriptase/MT-SP1-deficient mice developed to term but uniformly died within 48 h of birth. All epidermal surfaces of newborn mice were grossly abnormal with a dry, red, shiny, and wrinkled appearance. Matriptase/MT-SP1-deficiency caused striking malformations of the stratum corneum, characterized by dysmorphic and pleomorphic corneocytes and the absence of vesicular bodies in transitional layer cells. This aberrant skin development seriously compromised both inward and outward epidermal barrier function, leading to the rapid and fatal dehydration of Matriptase/MT-SP1-deficient pups. Loss of Matriptase/MT-SP1 also seriously affected hair follicle development resulting in generalized follicular hypoplasia, absence of erupted vibrissae, lack of vibrissal hair canal formation, ingrown vibrissae, and wholesale abortion of vibrissal follicles. Furthermore, Matriptase/MT-SP1-deficiency resulted in dramatically increased thymocyte apoptosis, and depletion of thymocytes. This study demonstrates that Matriptase/MT-SP1 has pleiotropic functions in the development of the epidermis, hair follicles, and cellular immune system.

Identification of single nucleotide polymorphisms in the human kallikrein 10 (KLK10) gene and their association with prostate, breast, testicular, and ovarian cancers

BACKGROUND

The KLK10 gene (also known as the normal epithelial cell-specific 1 gene) is a member of the expanded human kallikrein gene family. Recently, it has been reported that KLK10 is a tumor suppressor gene and that its expression is downregulated in various forms of cancer and cancer cell lines. KLK10 is also upregulated in ovarian cancer. We thus hypothesized that the KLK10 gene may be a target for mutations in various cancers.

METHODS

We sequenced the five coding exons of the KLK10 gene using genomic DNA from various tumors, normal tissues, and blood, by PCR amplification and automated sequencing.

RESULTS

In none of the tumor-derived DNAs, we identified somatic mutations that could inactivate this gene. However, we identified a prevalent germline single nucleotide variation at codon 50 (exon 3) of this gene [GCC (alanine) to TCC (serine)]. The GCC genotype was less prevalent in prostatic cancer patients in comparison to control subjects (P = 0.027) but no differences were seen with testicular, ovarian, and breast cancer. We also identified four genetic variations in exon 4, at codons106 [GGC (glycine) to GGA (glycine)], codon 112 [ACG (threonine) to ACC (threonine)], codon 141 [CTA (leucine) to CTG (leucine)], and at codon 149 [CCG (proline) to CTG (leucine)]. None of these variations was significantly different between normal subjects and cancer groups.

CONCLUSIONS

We found no evidence for somatic mutations of the KLK10 gene in cancers of the prostate, breast, ovary, and testis. The single nucleotide variation at codon 50 appears to be associated with prostate cancer risk.

New functions for the matrix metalloproteinases in cancer progression

Matrix metalloproteinases (MMPs) have long been associated with cancer-cell invasion and metastasis. This provided the rationale for clinical trials of MMP inhibitors, unfortunately with disappointing results. We now know, however, that the MMPs have functions other than promotion of invasion, have substrates other than components of the extracellular matrix, and that they function before invasion in the development of cancer. With this knowledge in hand, can we rethink the use of MMP inhibitors in the clinic?

Differential regulation of matrix metalloproteinase-9, tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2 expression in co-cultures of prostate cancer and stromal cells

Tumor-stromal interactions have been suggested to be a critical factor in both tumor invasion and tumor metastasis. Here, we examined the role of tumor-stromal interactions using co-cultures of prostate cancer (PC) cells derived from primary and metastatic tumors with primary or immortalized stromal (fibroblast and smooth muscle) cells and their effect on matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) expression. Co-cultures of PC and stromal cells showed enhanced levels of pro-MMP-9 and reduced levels of TIMP-1 and TIMP-2. Whereas enhanced expression of pro-MMP-9 occurred in PC cells, the TIMPs were down-regulated in stromal cells. Induction of pro-MMP-9 and reduction of TIMP expression did not require cell-cell contact and were mediated by a soluble factor(s) present in the conditioned medium of the effector cell. Collagen I is a potent inducer of pro-MMP-9 in PC cells. Consistently, preliminary characterization of the soluble factor in the fibroblast conditioned medium revealed m.w. of approximately 100 to 250 kDa, and its effect on pro-MMP-9 expression was partly inhibited by an anti-alpha2 integrin antibody, a major collagen I receptor. Expression of pro-MMP-9 protein and mRNA was also induced in metastatic PC-3 cells grown in human fetal bone implants in SCID mice. Together, these findings demonstrate the importance of tumor-stromal interactions in the regulation of MMP and TIMP expression and their potential role in PC progression.

Nitric oxide (NO), methylation and TIMP-1 expression in BL6 melanoma cells transfected with MHC class I genes

We have previously found that transfection of BL6-8 melanoma cells with the H-2K, but not H-2D/L genes resulted in loss of their metastatic ability that was associated with decrease in their invasiveness and up-regulation of TIMP-1 expression. In the present study using the methylation-specific PCR (MSP) we found that lack of TIMP-1 expression in BL6-8 is associated with methylation in the TIMP-1 5' regulatory area. In the H-2Kb transfected CL8-1 melanoma cells up-regulation of TIMP-1 was in parallel with loss of TIMP-1 gene methylation. Treatment of BL6-8 with 5-azacytidine or with an inhibitor of histone deacetylase trichostatin A resulted in up-regulation of TIMP-1 expression. These results indicate that methylation and histone deacetylation play an important role in transcription repression of TIMP-1 in BL6 melanoma cells. Some data showed that nitric oxide (NO) could affect methylation and expression of various gene. Therefore we analyzed NO production in B16 melanoma cell lines with different expression of TIMP-1. We have found that B16F10 and BL6-8 melanoma cells do not express TIMP-1 and do not produce nitric oxide (NO) even after stimulation with IFN-gamma and LPS. However, BL6-8 cells transfected with H-2Kb or H-2Kd, but not H-2Dd or H-2Ld gene expressed TIMP-1 and produced NO constitutevely. NO production in these cells was further stimulated by IFN-gamma and LPS. Northern blot analysis showed that expression of iNOS was paralleled with TIMP-1 expression in the tested melanoma cells. However, NO produced by SNAP or inhibition of NO production by NMA did not affect TIMP-1 expression in the tested melanoma cells. Thus, TIMP-1 expression and NO production in BL6 melanoma cells transfected with MHC class I gene coincides but it remains unclear whether NO is responsible for the change in TIMP-1 methylation and expression.

Estrogen prevents the lipopolysaccharide-induced inflammatory response in microglia

After neuronal injury and in several neurodegenerative diseases, activated microglia secrete proinflammatory molecules that can contribute to the progressive neural damage. The recent demonstration of a protective role of estrogen in neurodegenerative disorders in humans and experimental animal models led us to investigate whether this hormone regulates the inflammatory response in the CNS. We here show that estrogen exerts an anti-inflammatory activity on primary cultures of rat microglia, as suggested by the blockage of the phenotypic conversion associated with activation and by the prevention of lipopolysaccharide-induced production of inflammatory mediators: inducible form of NO synthase (iNOS), prostaglandin-E(2) (PGE(2)), and metalloproteinase-9 (MMP-9). These effects are dose-dependent, maximal at 1 nm 17beta-estradiol, and can be blocked by the estrogen receptor (ER) antagonist ICI 182,780. The demonstration of ERalpha and ERbeta expression in microglia and macrophages and the observation of estrogen blockade of MMP-9 mRNA accumulation and MMP-9 promoter induction further support the hypothesis of a genomic activity of estrogen via intracellular receptors. This is the first report showing an anti-inflammatory activity of estrogen in microglia. Our study proposes a novel explanation for the protective effects of estrogen in neurodegenerative and inflammatory diseases and provides new molecular and cellular targets for the screening of ER ligands acting in the CNS.

Membrane-type 1 matrix metalloproteinase cleaves CD44 and promotes cell migration

Migratory cells including invasive tumor cells frequently express CD44, a major receptor for hyaluronan and membrane-type 1 matrix metalloproteinase (MT1-MMP) that degrades extracellular matrix at the pericellular region. In this study, we demonstrate that MT1-MMP acts as a processing enzyme for CD44H, releasing it into the medium as a soluble 70-kD fragment. Furthermore, this processing event stimulates cell motility; however, expression of either CD44H or MT1-MMP alone did not stimulate cell motility. Coexpression of MT1-MMP and mutant CD44H lacking the MT1-MMP-processing site did not result in shedding and did not promote cell migration, suggesting that the processing of CD44H by MT1-MMP is critical in the migratory stimulation. Moreover, expression of the mutant CD44H inhibited the cell migration promoted by CD44H and MT1-MMP in a dominant-negative manner. The pancreatic tumor cell line, MIA PaCa-2, was found to shed the 70-kD CD44H fragment in a MT1-MMP-dependent manner. Expression of the mutant CD44H in the cells as well as MMP inhibitor treatment effectively inhibited the migration, suggesting that MIA PaCa-2 cells indeed use the CD44H and MT1-MMP as migratory devices. These findings revealed a novel interaction of the two molecules that have each been implicated in tumor cell migration and invasion.