Matrix metalloproteinases in tumorigenesis: an evolving paradigm

Domain structure and function of matrix metalloprotease 23 (MMP23): role in potassium channel trafficking

MMP23 is a member of the matrix metalloprotease family of zinc- and calcium-dependent endopeptidases, which are involved in a wide variety of cellular functions. Its catalytic domain displays a high degree of structural homology with those of other metalloproteases, but its atypical domain architecture suggests that it may possess unique functional properties. The N-terminal MMP23 pro-domain contains a type-II transmembrane domain that anchors the protein to the plasma membrane and lacks the cysteine-switch motif that is required to maintain other MMPs in a latent state during passage to the cell surface. Instead of the C-terminal hemopexin domain common to other MMPs, MMP23 contains a small toxin-like domain (TxD) and an immunoglobulin-like cell adhesion molecule (IgCAM) domain. The MMP23 pro-domain can trap Kv1.3 but not closely-related Kv1.2 channels in the endoplasmic reticulum, preventing their passage to the cell surface, while the TxD can bind to the channel pore and block the passage of potassium ions. The MMP23 C-terminal IgCAM domain displays some similarity to Ig-like C2-type domains found in IgCAMs of the immunoglobulin superfamily, which are known to mediate protein-protein and protein-lipid interactions. MMP23 and Kv1.3 are co-expressed in a variety of tissues and together are implicated in diseases including cancer and inflammatory disorders. Further studies are required to elucidate the mechanism of action of this unique member of the MMP family.

Pharmacological and molecular effects of platinum(II) complexes involving 7-azaindole derivatives

The in vitro antitumour activity studies on a panel of human cancer cell lines (A549, HeLa, G-361, A2780, and A2780R) and the combined in vivo and ex vivo antitumour testing on the L1210 lymphocytic leukaemia model were performed on the cis-[PtCl₂(naza)₂] complexes (1–3) involving the 7-azaindole derivatives (naza). The platinum(II) complexes showed significantly higher in vitro cytotoxic effects on cell-based models, as compared with cisplatin, and showed the ability to avoid the acquired resistance of the A2780R cell line to cisplatin. The in vivo testing of the complexes (applied at the same dose as cisplatin) revealed their positive effect on the reduction of cancerous tissues volume, even if it is lower than that of cisplatin, however, they also showed less serious adverse effects on the healthy tissues and the health status of the treated mice. The results of ex vivo assays revealed that the complexes 1–3 were able to modulate the levels of active forms of caspases 3 and 8, and the transcription factor p53, and thus activate the intrinsic (mitochondrial) pathway of apoptosis. The pharmacological observations were supported by both the histological and immunohistochemical evaluation of isolated cancerous tissues. The applicability of the prepared complexes and their fate in biological systems, characterized by the hydrolytic stability and the thermodynamic aspects of the interactions with cysteine, reduced glutathione, and human serum albumin were studied by the mass spectrometry and isothermal titration calorimetric experiments.

Oxidative stress and extracellular matrices after hepatectomy and liver transplantation in rats

AIM

To investigate oxidative stress (OS)-mediated damage and the behavior of extracellular matrices in various rat models because shear stress with portal hypertension and cold ischemia/warm reperfusion injury trigger the liver regeneration cascade after surgery. These injuries also cause fatal liver damage.

METHODS

Rats were divided into four groups according to the surgery performed: control; hepatectomy with 40% liver remnant (60% hepatectomy); orthotopic liver transplantation (OLT) with whole liver graft (100% OLT); and split OLT (SOLT) with 40% graft (40% SOLT). Survival was evaluated. Blood and liver samples were collected at 6 h after surgery. Biochemical and histopathological examinations were performed. OS-induced damage, 4-hydroxynonenal, ataxia-telangiectasia mutated kinase, histone H2AX, phosphatidylinositol 3-kinase (PI3K) and Akt were evaluated by western blotting. Behavior of extracellular matrices, matrix metalloproteinase (MMP)-9, MMP-2, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 were also evaluated by western blotting and zymography.

RESULTS

Although 100% OLT survived, 60% hepatectomy and 40% SOLT showed poor survival. Histopathological, immunohistological, biochemical and protein assays revealed that 60% hepatectomy, 100% OLT and 40% SOLT showed liver damage. PI3K and Akt were decreased in 60% hepatectomy and 40% SOLT. For protein expression, 40% SOLT showed differences in MMP-9, MMP-2 and TIMP-2. TIMP-1 showed differences in 60% hepatectomy and 40% SOLT. For protein activity, MMP-9 demonstrated significant differences in 60% hepatectomy, 100% OLT and 40% SOLT.

CONCLUSION

Under conditions with an insufficient liver remnant, prevention of OS-induced damage via the Akt/PI3K pathway may be key to improve the postoperative course. MMP-9 may be also a therapeutic target after surgery.

The role of matrix metalloproteinases in colorectal cancer

In the United States, colorectal cancer (CRC) is the third leading cause of cancer mortality, with limited treatment options for those with advanced disease. Matrix metalloproteinases (MMPs) are important for maintaining extracellular homeostasis but also play a prominent role in cancer cell invasion and dissemination. Expression levels of MMP-1, -2, -7, -9 and -13 correlate with worse outcomes; MMP-12 expression appears to be protective. Hence, MMPs are attractive therapeutic targets. Previous clinical trials using broad-spectrum MMP inhibitors were disappointing because of off-target toxicity and lack of efficacy. Now, the availability of safer, more selective inhibitors has renewed interest in therapeutic targeting of MMPs.

SAP domain-dependent Mkl1 signaling stimulates proliferation and cell migration by induction of a distinct gene set indicative of poor prognosis in breast cancer patients

Background

The main cause of death of breast cancer patients is not the primary tumor itself but the metastatic disease. Identifying breast cancer-specific signatures for metastasis and learning more about the nature of the genes involved in the metastatic process would 1) improve our understanding of the mechanisms of cancer progression and 2) reveal new therapeutic targets. Previous studies showed that the transcriptional regulator megakaryoblastic leukemia-1 (Mkl1) induces tenascin-C expression in normal and transformed mammary epithelial cells. Tenascin-C is known to be expressed in metastatic niches, is highly induced in cancer stroma and promotes breast cancer metastasis to the lung.

Methods

Using HC11 mammary epithelial cells overexpressing different Mkl1 constructs, we devised a subtractive transcript profiling screen to identify the mechanism by which Mkl1 induces a gene set co-regulated with tenascin-C. We performed computational analysis of the Mkl1 target genes and used cell biological experiments to confirm the effect of these gene products on cell behavior. To analyze whether this gene set is prognostic of accelerated cancer progression in human patients, we used the bioinformatics tool GOBO that allowed us to investigate a large breast tumor data set linked to patient data.

Results

We discovered a breast cancer-specific set of genes including tenascin-C, which is regulated by Mkl1 in a SAP domain-dependent, serum response factor-independent manner and is strongly implicated in cell proliferation, cell motility and cancer. Downregulation of this set of transcripts by overexpression of Mkl1 lacking the SAP domain inhibited cell growth and cell migration. Many of these genes are direct Mkl1 targets since their promoter-reporter constructs were induced by Mkl1 in a SAP domain-dependent manner. Transcripts, most strongly reduced in the absence of the SAP domain were mechanoresponsive. Finally, expression of this gene set is associated with high-proliferative poor-outcome classes in human breast cancer and a strongly reduced survival rate for patients independent of tumor grade.

Conclusions

This study highlights a crucial role for the transcriptional regulator Mkl1 and its SAP domain during breast cancer progression. We identified a novel gene set that correlates with bad prognosis and thus may help in deciding the rigor of therapy.

Matrix metalloproteinase-7 and matrix metalloproteinase-25 in oral tongue squamous cell carcinoma

BACKGROUND

Predicting the clinical course of early-stage oral tongue squamous cell carcinoma (SCC) is challenging. As matrix metalloproteinases (MMPs) are enzymes associated with invasion, metastasis, and poor survival in many cancers, we examined MMP-7 and MMP-25 in oral tongue SCC.

METHODS

We used tissue microarray (TMA) technique and immunohistochemistry to study the expression of MMP-7 and MMP-25 in 73 patients with stage I to II oral tongue SCC and compared their immunoexpressions with clinical data.

RESULTS

Immunohistochemistry revealed MMP-7 and MMP-25 expression in 90% (n = 63 of 70) and 90% (n = 64 of 71) of the tumors, respectively. MMP-7 protein expression was associated with presence of occult cervical metastases (odds ratio [OR], 3.67; p = .013), increased invasion depth (OR, 4.60; p = .005), and higher tumor grade (OR, 3.30; p = .007). MMP-7 expression was predictive for poor outcome (p = .021). Immunostaining of MMP-25 did not correlate with any clinical parameters.

CONCLUSION

We conclude that MMP-7, but not MMP-25, expression may have prognostic significance in early-stage oral tongue SCC.

Transforming growth factor-beta and matrix metalloproteinases: functional interactions in tumor stroma-infiltrating myeloid cells

Transforming growth factor-beta (TGF-β) is a pleiotropic factor with several different roles in health and disease. In tumorigenesis, it may act as a protumorigenic factor and have a profound impact on the regulation of the immune system response. Matrix metalloproteinases (MMPs) are a family that comprises more than 25 members, which have recently been proposed as important regulators acting in tumor stroma by regulating the response of noncellular and cellular microenvironment. Tumor stroma consists of several types of resident cells and infiltrating cells derived from bone marrow, which together play crucial roles in the promotion of tumor growth and metastasis. In cancer cells, TGF-β regulates MMPs expression, while MMPs, produced by either cancer cells or residents' stroma cells, activate latent TGF-β in the extracellular matrix, together facilitating the enhancement of tumor progression. In this review we will focus on the compartment of myeloid stroma cells, such as tumor-associated macrophages, neutrophils, and dendritic and mast cells, which are potently regulated by TGF-β and produce large amounts of MMPs. Their interplay and mutual implications in the generation of pro-tumorigenic cancer microenvironment will be analyzed.

Tumor necrosis factor-α-induced a disintegrin and metalloprotease 10 increases apoptosis resistance in prostate cancer cells

In developed countries, prostate cancer (PCa) is the second most frequently diagnosed type of cancer and the third most common cause of cancer-related mortality in males. Compared with western countries, the morbidity rate of PCa in China is markedly lower, however, it is rising annually. The etiology of PCa is unclear, therefore, to investigate how a disintegrin and metalloprotease 10 (ADAM10) functions in PCa, ADAM10 mRNA and protein levels induced by tumor necrosis factor (TNF)-α were identified using polymerase chain reaction and flow cytometry, respectively. To investigate the mechanism of ADAM10 activity in PCa, specific inhibitors were used, and DNA transfection and RNA interference technology were employed to identify the interaction between ADAM10 and the Fas ligand (L). The results indicated that TNF-α induced ADAM10 expression in a time- and dose-dependent manner through the p38 mitogen-activated protein kinase/necrosis factor-κB signaling pathway. ADAM10 hydrolyzed FasL and contributed to apoptosis resistance of the tumor cells. These observations indicate a promising therapeutic modality for the treatment of apoptosis-resistant PCa, by targeting ADAM10 sheddase activity.

First-in-human phase I study of PRS-050 (Angiocal), an Anticalin targeting and antagonizing VEGF-A, in patients with advanced solid tumors

Background

To report the nonrandomized first-in-human phase I trial of PRS-050, a novel, rationally engineered Anticalin based on human tear lipocalin that targets and antagonizes vascular endothelial growth factor A (VEGF-A).

Methods

Patients with advanced solid tumors received PRS-050 at 0.1 mg/kg to 10 mg/kg by IV in successive dosing cohorts according to the 3+3 escalation scheme. The primary end point was safety.

Results

Twenty-six patients were enrolled; 25 were evaluable. Two patients experienced dose-limiting toxicity, comprising grade (G) 3 hypertension and G3 pyrexia, respectively. The maximum tolerated dose was not reached. Most commonly reported treatment-emergent adverse events (AEs) included chills (52%; G3, 4%), fatigue (52%; G3, 4%), hypertension (44%; G3, 16%), and nausea (40%, all G1/2). No anti–PRS-050 antibodies following multiple administration of the drug were detected. PRS-050 showed dose-proportional pharmacokinetics (PK), with a terminal half-life of approximately 6 days. Free VEGF-A was detectable at baseline in 9/25 patients, becoming rapidly undetectable after PRS-050 infusion for up to 3 weeks. VEGF-A/PRS-050 complex was detectable for up to 3 weeks at all dose levels, including in patients without detectable baseline-free VEGF-A. We also detected a significant reduction in circulating matrix metalloproteinase 2, suggesting this end point could be a pharmacodynamic (PD) marker of the drug’s activity.

Conclusions

PRS-050, a novel Anticalin with high affinity for VEGF-A, was well-tolerated when administered at the highest dose tested, 10 mg/kg. Based on target engagement and PK/PD data, the recommended phase II dose is 5 mg/kg every 2 weeks administered as a 120-minute infusion.

Trial Registration

ClinicalTrials.gov NCT01141257 http://clinicaltrials.gov/ct2/show/NCT01141257

New markers of apoptosis in children on chronic dialysis

Enhanced apoptosis is characteristic for chronic kidney disease (CKD). A specific type of apoptosis, anoikis, is connected with the extracellular matrix turnover and cell detachment. Although E-cadherin, extracellular matrix metalloproteinase inducer (EMMPRIN) and matrix metalloproteinase (MMP)-8 may play an important role in this process, they have not been analyzed in any nephrological aspect, either in CKD. The aim of study was to evaluate the serum concentrations of E-cadherin, EMMPRIN and their potential regulators (MMP-8, MMP-7, TIMP-1, TIMP-2), with relevance to apoptosis/cell damage markers (sFas, sFasL, Hsp27), in children with CKD. 39 CKD children stages 3–4, 26 CKD children stage 5 still on conservative treatment, 19 patients on hemodialysis (HD), 22 children on automated peritoneal dialysis (APD) and 30 controls were examined. Serum concentrations of those parameters were assessed by ELISA. Median E-cadherin, EMMPRIN and MMP-8 values were significantly increased in patients on dialysis versus those in pre-dialysis period and versus controls. The highest values were noticed in the HD subjects. Regression analysis revealed that EMMPRIN and MMP-8 predicted various apoptosis markers, whereas E-cadherin turned out the best predictor of both apoptosis (Hsp27, sFas, sFasL) and matrix turnover (MMP-7, TIMP-1, TIMP-2) indexes in dialyzed patients. Children with CKD are prone to E-cadherin, EMMPRIN and MMP-8 elevation, aggravated by the dialysis commencement and most evident on hemodialysis. Correlations between parameters suggest their role as indexes of apoptosis in children on dialysis. E-cadherin seems the most accurate marker of anoikis in this population.

Expression profiles of angiogenesis-related proteins in prevascular three-dimensional tissues using cell-sheet engineering

The prefabrication of endothelial cell network assembly (ECNA) in tissue-engineer multi-layered cell-sheets, known as in vitro prevascularization, is beneficial strategy for inducing anastomosis with the host vasculature after transplantation. However, the mechanisms of neovascularization via transplanted prevascular cell-sheets are unknown. This study investigated neovascularization process and angiogenesis-related protein secretion by prevascular cell-sheets. Prevascular (ECNA-positive) double-layered fibroblast (FB) sheets were created by sandwiching human aortic endothelial cells (HAECs) between two human dermal FB sheets. As the ECNA-negative control, FBs-sandwiching double-layered FB sheets were used. Two types of cell-sheets were subcutaneously transplanted into immune-deficient rats. At 3 days after transplantation, induction of the newly-formed microvessels near the host vasculature was observed in the ECNA-positive cell-sheet. In contrast, no neovessel was observed in the ECNA-negative cell-sheet at 1 week after transplantation. Consequently, the secretion of angiogenesis-related proteins in conditioned media of each cell-sheet cultured for 3 days were compared. The levels of hepatocyte growth factor (HGF), placenta growth factor (PlGF) and matrix metalloproteinase-9 (MMP-9) significantly increased in the ECNA-positive cell-sheets. These results suggested that these molecules might involve in neovascularization after the transplantation of prevascular cell-sheets. These findings may contribute to understanding its mechanism.

Tpl2 knockout keratinocytes have increased biomarkers for invasion and metastasis

Skin cancer is the most common form of cancer in the USA, with an estimated two million cases diagnosed annually. Tumor progression locus 2 (Tpl2), also known as MAP3K8, is a serine/threonine protein kinase in the mitogen-activated protein kinase signal transduction cascade. Tpl2 was identified by our laboratory as having a tumor suppressor function in skin carcinogenesis, with the absence of this gene contributing to heightened inflammation and increased skin carcinogenesis. In this study, we used gene expression profiling to compare expression levels between Tpl2 (+/+) and Tpl2 (-) (/-) keratinocytes. We identified over 2000 genes as being differentially expressed between genotypes. Functional annotation analysis identified cancer, cell growth/proliferation, cell death, cell development, cell movement and cell signaling as the top biological processes to be differentially regulated between genotypes. Further microarray analysis identified several candidate genes, including Mmp1b, Mmp2, Mmp9 and Mmp13, involved in migration and invasion to be upregulated in Tpl2 (-) (/-) keratinocytes. Moreover, Tpl2 (-/-) keratinocytes had a significant downregulation in the matrix metalloproteinase (MMP) inhibitor Timp3. Real-time PCR validated the upregulation of the MMPs in Tpl2 (-/-) keratinocytes and zymography confirmed that MMP2 and MMP9 activity was higher in conditioned media from Tpl2 (-/-) keratinocytes. Immunohistochemistry confirmed higher MMP9 staining in 12-O-tetradecanoylphorbol-13-acetate-treated skin from Tpl2 (-/-) mice and grafted tumors formed from v-ras(Ha) retrovirus-infected Tpl2 (-/-) keratinocytes. Additionally, Tpl2 (-/-) keratinocytes had significantly higher invasion, malignant conversion rates and increased endothelial cell tube formation when compared with Tpl2 (+/+) keratinocytes. In summary, our studies reveal that keratinocytes from Tpl2 (-/-) mice demonstrate a higher potential to be invasive and metastatic.

Interrogating tumor metabolism and tumor microenvironments using molecular positron emission tomography imaging. Theranostic approaches to improve therapeutics

Positron emission tomography (PET) is a noninvasive molecular imaging technology that is becoming increasingly important for the measurement of physiologic, biochemical, and pharmacological functions at cellular and molecular levels in patients with cancer. Formation, development, and aggressiveness of tumor involve a number of molecular pathways, including intrinsic tumor cell mutations and extrinsic interaction between tumor cells and the microenvironment. Currently, evaluation of these processes is mainly through biopsy, which is invasive and limited to the site of biopsy. Ongoing research on specific target molecules of the tumor and its microenvironment for PET imaging is showing great potential. To date, the use of PET for diagnosing local recurrence and metastatic sites of various cancers and evaluation of treatment response is mainly based on [(18)F]fluorodeoxyglucose ([(18)F]FDG), which measures glucose metabolism. However, [(18)F]FDG is not a target-specific PET tracer and does not give enough insight into tumor biology and/or its vulnerability to potential treatments. Hence, there is an increasing need for the development of selective biologic radiotracers that will yield specific biochemical information and allow for noninvasive molecular imaging. The possibility of cancer-associated targets for imaging will provide the opportunity to use PET for diagnosis and therapy response monitoring (theranostics) and thus personalized medicine. This article will focus on the review of non-[(18)F]FDG PET tracers for specific tumor biology processes and their preclinical and clinical applications.

Enhanced anticancer activity of nanopreparation containing an MMP2-sensitive PEG-drug conjugate and cell-penetrating moiety

In response to the challenges of cancer chemotherapeutics, including poor physicochemical properties, low tumor targeting, insufficient tumor cell internalization/bioavailability, and side effects, we developed a unique tumor-targeted micellar drug-delivery platform. Using paclitaxel as a model therapeutic, a nanopreparation composed of a matrix metalloproteinase 2 (MMP2)-sensitive self-assembly PEG 2000-paclitaxel conjugate (as a prodrug and MMP 2-sensitive moiety), transactivating transcriptional activator peptide-PEG1000-phosphoethanolamine (PE) (a cell-penetrating enhancer), and PEG1000-PE (a nanocarrier building block) was prepared. Several major drug delivery strategies, including self-assembly, PEGylation, the enhanced permeability and retention effect, stimulus sensitivity, a cell-penetrating moiety, and the concept of prodrug, were used in design of this nanoparticle in a collaborative manner. The nanopreparation allowed superior cell internalization, cytotoxicity, tumor targeting, and antitumor efficacy in vitro and in vivo over its nonsensitive counterpart, free paclitaxel and conventional micelles. This uniquely engineered nanoparticle has potential for effective intracellular delivery of drug into cancer cells.

BMP4 inhibits the proliferation of breast cancer cells and induces an MMP-dependent migratory phenotype in MDA-MB-231 cells in 3D environment

Background

Bone morphogenetic protein 4 (BMP4) belongs to the transforming growth factor β (TGF-β) family of proteins. BMPs regulate cell proliferation, differentiation and motility, and have also been reported to be involved in cancer pathogenesis. We have previously shown that BMP4 reduces breast cancer cell proliferation through G1 cell cycle arrest and simultaneously induces migration in a subset of these cell lines. Here we examined the effects of BMP4 in a more physiological environment, in a 3D culture system.

Methods

We used two different 3D culture systems; Matrigel, a basement membrane extract from mouse sarcoma cells, and a synthetic polyethylene glycol (PEG) gel. AlamarBlue reagent was used for cell proliferation measurements and immunofluorescence was used to determine cell polarity. Expression of cell cycle regulators was examined by Western blot and matrix metalloproteinase (MMP) expression by qRT-PCR.

Results

The MCF-10A normal breast epithelial cells formed round acini with correct apicobasal localization of α6 integrin in Matrigel whereas irregular structures were seen in PEG gel. The two 3D matrices also supported dissimilar morphology for the breast cancer cells. In PEG gel, BMP4 inhibited the growth of MCF-10A and the three breast cancer cell lines examined, thus closely resembling the 2D culture conditions, but in Matrigel, no growth inhibition was observed in MDA-MB-231 and MDA-MB-361 cells. Furthermore, BMP4 induced the expression of the cell cycle inhibitor p21 both in 2D and 3D culture, thereby partly explaining the growth arrest. Interestingly, MDA-MB-231 cells formed large branching, stellate structures in response to BMP4 treatment in Matrigel, suggestive of increased cell migration or invasion. This effect was reversed by Batimastat, a broad-spectrum MMP inhibitor, and subsequent analyses showed BMP4 to induce the expression of MMP3 and MMP14, that are thus likely to be responsible for the stellate phenotype.

Conclusions

Taken together, our results show that Matrigel provides a more physiological environment for breast epithelial cells than PEG gel. Moreover, BMP4 partly recapitulates in 3D culture the growth suppressive abilities previously seen in 2D culture and induces an MMP-dependent migratory phenotype in MDA-MB-231 cells.

Therapeutic targets associated to E-cadherin dysfunction in gastric cancer

INTRODUCTION

Epithelial cadherin (E-cadherin) plays a key role in epithelial cell-cell adhesion, contributing to tissue differentiation and homeostasis. Throughout the past decades, research has shed light on the molecular mechanisms underlying E-cadherin's role in tumor progression, namely in invasion and metastization. Emerging evidence established E-cadherin as a tumor suppressor and suggests that targeting E-cadherin or downstream signaling molecules may constitute effective cancer therapeutics.

AREAS COVERED

This review aims to cover E-cadherin-mediated signaling during cancer development and progression and highlight putative therapeutic targets.

EXPERT OPINION

Reconstitution of E-cadherin expression or targeting of E-cadherin downstream molecules holds promise in cancer therapies. Considering the high frequency of CDH1 promoter hypermethylation as a second hit in malignant lesions from hereditary diffuse gastric cancer patients, histone deacetylase inhibitors are potential therapeutic agents in combination with conventional chemotherapy, specifically in initial tumor stages. Concerning E-cadherin-mediated signaling, we propose that HER receptors (as epidermal growth factor receptor) and Notch downstream targets are clinically relevant and should be considered in gastric cancer therapeutics and control.

miRNA-29c suppresses lung cancer cell adhesion to extracellular matrix and metastasis by targeting integrin β1 and matrix metalloproteinase2 (MMP2)

Our pilot study using miRNA arrays found that miRNA-29c (miR-29c) is differentially expressed in the paired low-metastatic lung cancer cell line 95C compared to the high-metastatic lung cancer cell line 95D. Bioinformatics analysis shows that integrin β1 and matrix metalloproteinase 2 (MMP2) could be important target genes of miR-29c. Therefore, we hypothesized that miR-29c suppresses lung cancer cell adhesion to extracellular matrix (ECM) and metastasis by targeting integrin β1 and MMP2. The gain-of-function studies that raised miR-29c expression in 95D cells by using its mimics showed reductions in cell proliferation, adhesion to ECM, invasion and migration. In contrasts, loss-of-function studies that reduced miR-29c by using its inhibitor in 95C cells promoted proliferation, adhesion to ECM, invasion and migration. Furthermore, the dual-luciferase reporter assay demonstrated that miR-29c inhibited the expression of the luciferase gene containing the 3′-UTRs of integrin β1 and MMP2 mRNA. Western blotting indicated that miR-29c downregulated the expression of integrin β1 and MMP2 at the protein level. Gelatin zymography analysis further confirmed that miR-29c decreased MMP2 enzyme activity. Nude mice with xenograft models of lung cancer cells confirmed that miR-29c inhibited lung cancer metastasis in vivo, including bone and liver metastasis. Taken together, our results demonstrate that miR-29c serves as a tumor metastasis suppressor, which suppresses lung cancer cell adhesion to ECM and metastasis by directly inhibiting integrin β1 and MMP2 expression and by further reducing MMP2 enzyme activity. The results show that miR-29c may be a novel therapeutic candidate target to slow lung cancer metastasis.

The bacterial protein azurin impairs invasion and FAK/Src signaling in P-cadherin-overexpressing breast cancer cell models

P-cadherin overexpression occurs in about 30% of all breast carcinomas, being a poor prognostic factor for breast cancer patients. In a cellular background of wild-type E-cadherin, we have previously shown that its expression promotes invasion, motility and migration of breast cancer cells due to the induced secretion of metalloproteases (MMPs) to the extracellular medium and to the concomitant shedding of a pro-invasive soluble form of this protein (sP-cad). Azurin is secreted by Pseudomonas aeruginosa and induces in vitro and in vivo cytotoxicity after its preferential penetration in human cancer cells relative to normal cells. Three different breast cancer cell lines, MCF-7/AZ.Mock, MCF-7/AZ.Pcad and SUM149 were treated with sub-killing doses of azurin. Invasion of these cells was measured using Matrigel Invasion Assays and MTT assays were performed to determine cell viability upon treatment and the effects on cadherins expression was determined by Western blot and Immunofluorescence. Gelatin Zymography was used to determine activity of MMP2 in the conditioned media of azurin treated and untreated cells and the phosphorylation levels of intracellular signaling proteins were determined by Western blot. The invasive phenotype of these breast cancer cells was significantly reduced by azurin. Azurin (50–100 µM) also caused a specific decrease on P-cadherin protein levels from 30–50% in MCF-7/AZ.Pcad and SUM149 breast cancer cell lines, but the levels of E-cadherin remain unaltered. More, the levels of sP-cad and the activity of MMP2 were reduced in the extracellular media of azurin treated cells and we also observed a decrease in the phosphorylation levels of both FAK and Src proteins. Our data show that azurin specifically targets P-cadherin, not E-cadherin, abrogating P-cadherin-mediated invasive effects and signaling. Therefore, azurin could possibly be considered a therapeutic tool to treat poor-prognosis breast carcinomas overexpressing P-cadherin in a wild type E-cadherin context.

LRP-1: a checkpoint for the extracellular matrix proteolysis

Low-density lipoprotein receptor-related protein-(LRP-1) is a large endocytic receptor that binds more than 35 ligands and exhibits signaling properties. Proteinases capable of degrading extracellular matrix (ECM), called matrix proteinases in this paper, are mainly serine proteinases: the activators of plasminogen into plasmin, tissue-type (tPA) and urokinase-type (uPA) plasminogen activators, and the members of the matrix metalloproteinase (MMP) family. LRP-1 is responsible for clearing matrix proteinases, complexed or not with inhibitors. This paper attempts to summarize some aspects on the cellular and molecular bases of endocytic and signaling functions of LRP-1 that modulate extra- and pericellular levels of matrix proteinases.

Inhibition of cell migration by ouabain in the A549 human lung cancer cell line

The Na⁺/K⁺-ATPase α subunit is highly expressed in malignant cells. Ouabain, a cardioactive glycoside, binds to the Na⁺/K⁺-ATPase α subunit and inhibits the activity of Na⁺/K⁺-ATPase. In the present study, the effect of ouabain on the migration of A549 cells was analyzed using the wound healing and transwell chamber migration assays. The impact of ouabain on the expression of E-cadherin, N-cadherin, vimentin, matrix metalloprotease (MMP)-2 and MMP-9 was also evaluated. Ouabain treatment not only inhibited the epidermal growth factor (EGF)-enhanced migration of A549 cells, but also inhibited the basal migration of A549 cells in the absence of EGF. Ouabain decreased the overexpression of N-cadherin and vimentin induced by EGF, and decreased the expression of MMP-2 and -9 in the presence or absence of EGF. Na⁺/K⁺-ATPase is a potent therapeutic target in lung cancer and these observations indicated that the Na⁺/K⁺-ATPase inhibitor, ouabain, retards the invasion of lung cancer cells.

Synergism between Hedgehog-GLI and EGFR signaling in Hedgehog-responsive human medulloblastoma cells induces downregulation of canonical Hedgehog-target genes and stabilized expression of GLI1

Aberrant activation of Hedgehog (HH) signaling has been identified as a key etiologic factor in many human malignancies. Signal strength, target gene specificity, and oncogenic activity of HH signaling depend profoundly on interactions with other pathways, such as epidermal growth factor receptor-mediated signaling, which has been shown to cooperate with HH/GLI in basal cell carcinoma and pancreatic cancer. Our experimental data demonstrated that the Daoy human medulloblastoma cell line possesses a fully inducible endogenous HH pathway. Treatment of Daoy cells with Sonic HH or Smoothened agonist induced expression of GLI1 protein and simultaneously prevented the processing of GLI3 to its repressor form. To study interactions between HH- and EGF-induced signaling in greater detail, time-resolved measurements were carried out and analyzed at the transcriptomic and proteomic levels. The Daoy cells responded to the HH/EGF co-treatment by downregulating GLI1, PTCH, and HHIP at the transcript level; this was also observed when Amphiregulin (AREG) was used instead of EGF. We identified a novel crosstalk mechanism whereby EGFR signaling silences proteins acting as negative regulators of HH signaling, as AKT- and ERK-signaling independent process. EGFR/HH signaling maintained high GLI1 protein levels which contrasted the GLI1 downregulation on the transcript level. Conversely, a high-level synergism was also observed, due to a strong and significant upregulation of numerous canonical EGF-targets with putative tumor-promoting properties such as MMP7, VEGFA, and IL-8. In conclusion, synergistic effects between EGFR and HH signaling can selectively induce a switch from a canonical HH/GLI profile to a modulated specific target gene profile. This suggests that there are more wide-spread, yet context-dependent interactions, between HH/GLI and growth factor receptor signaling in human malignancies.

Protopanaxatriol ginsenoside Rh1 inhibits the expression of matrix metalloproteinases and the in vitro invasion/migration of human astroglioma cells

Malignant gliomas are the most common and fatal brain tumors in adults. In particular, the strong invasiveness of glioma cells into the normal brain tissue makes eradication of glioma very difficult. Matrix metalloproteinases (MMPs) play a pivotal role in glioma invasion, and thus controlling MMP expression has been suggested as an important therapeutic target for brain tumors. In the present study, we investigated the effect of protopanaxatriol ginsenoside Rh1 on MMP expressions in human astroglioma U87MG and U373MG cells. RT-PCR analysis showed that Rh1 inhibits the mRNA expressions of MMP-1, -3, and -9 in PMA-stimulated U87MG and U373MG cells. Rh1 also suppressed the promoter activities of MMP-1, -3 and -9. The ELISA, Western blot, and zymographic analyses revealed that Rh1 inhibits the protein expression and/or enzymatic activity of MMP-1, -3 and -9. In accordance with the strong inhibitory effects of Rh1 on MMPs, Rh1 efficiently inhibited the invasion and migration of U87MG and U373MG glioma cells as demonstrated by Matrigel invasion assay and wound healing assay. Further mechanistic studies revealed that Rh1 inhibits MAPK and PI3K/Akt signaling pathways and downstream transcription factors such as NF-κB and AP-1, which play an important role in MMP gene expressions. The data collectively suggest that ginsenoside Rh1 may have a therapeutic potential for malignant gliomas.

The carotenoid lutein enhances matrix metalloproteinase-9 production and phagocytosis through intracellular ROS generation and ERK1/2, p38 MAPK, and RARβ activation in murine macrophages

Carotenoid lutein causes MMP-9 release that participates in macrophage phagocytosis.

Early studies have demonstrated the ability of dietary carotenoids to enhance immune response, but the mechanism underlying their influence on macrophage activity remains unclear. Here, we investigated the effects of carotenoids on macrophage activity. Carotenoids, including lutein and lycopene, enhanced MMP-9 activity in RAW264.7 macrophages. Lutein was chosen as a representative and analyzed further in this study. It increased the synthesis, activity, and release of MMP-9 in murine RAW264.7 and primary-cultured peritoneal macrophages. MMP-9 induction by lutein was through the transcriptional regulation of mmp-9. It was blunted by the MAPK inhibitors targeting ERK1/2 and p38 MAPK, the reagents that inhibit free radical signaling, and the inhibitors and siRNA targeting RARβ. Moreover, lutein induced Nox activation and intracellular ROS production at an early stage of treatment. This carotenoid also caused ERK1/2 and p38 MAPK activation, RARβ expression, and RAR interaction with its responsive element in the promoter region. These findings suggest the involvement of ROS, MAPKs, and RARβ activation in lutein-driven MMP-9 expression and release. Interestingly, lutein enhanced the phagocytic activity of macrophages, and the secreted MMP-9 appeared to be involved in this process. In summary, we provide evidence here for the first time that the carotenoid lutein induces intracellular ROS generation and MAPK and RARβ activation in macrophages, leading to an increase in MMP-9 release and macrophage phagocytosis. Our results demonstrate that lutein exerts an immunomodulatory effect on macrophages.

An ex vivo study on immunohistochemical localization of MMP-7 and MMP-9 in temporomandibular joint discs with internal derangement

Internal derangement (ID) is among the most common disorders of the temporomandibular joint (TMJ). Previous research by our group highlighted a correlation between apoptosis and TMJ ID. Metalloproteinases (MMP)-7 and -9 have been shown to play an important role in extracellular matrix ECM) homeostasis and, through it, in joint disc remodelling. The immunohistochemical expression of MMP-7 and -9 was investigated in discs from patients with TMJ ID and from healthy donors and compared with the degree of histological tissue degeneration. The collagen fibre arrangement in pathological discs exhibited varying degrees of disruption. New vessels were consistently detected; endothelial cells from these vessels were immunolabelled with both MMP-7 and MMP-9. More or less intense MMP-7 and MMP-9 immunolabelling was detected in the cytoplasm of disc cells from all patients. MMP-7 and MMP-9 immunostaining was significantly different between pathological and normal discs and correlated with the extent of histopathological degeneration. MMP-7 and MMP-9 upregulation in discs from patients with TMJ ID demonstrates their involvement in disc damage in this disorder. A greater understanding of these processes could help identify ways to curb MMP overproduction without affecting their tissue remodelling action. The design of specific inhibitors for these MMPs would not only help to gain insights into the biological roles of MMPs, but would also aid in developing therapeutic interventions for diseases associated with abnormal ECM degradation.

Basigin-2 is the predominant basigin isoform that promotes tumor cell migration and invasion and correlates with poor prognosis in epithelial ovarian cancer

Background

Basigin, which has four isoforms, has been demonstrated to be involved in progression of various human cancers. The aim of this study was to examine the prognostic value of basigin-2 protein expression in epithelial ovarian cancer. Furthermore, the function of basigin-2 in ovarian cancer was further investigated in cell culture models.

Methods

Immunohistochemistry staining was performed to investigate basigin-2 expression in a total of 146 ovarian tissue specimens. Kaplan Meier analysis and Cox proportional hazards model were applied to assess the relationship between basigin-2 and progression-free survival (PFS) and overall survival (OS). Real-time PCR, RT-PCR and western blot were used to explore basigin-2, basigin-3 and basigin-4 expression in ovarian cancer cell lines and tissues. To evaluate possible contributions of basigin-2 to MMP secretion and cell migration and invasion, the overexpression vectors pcDNA3.1-basigin-2 and basigin-2 siRNA were transfected into HO-8910 and HO-8910 PM cells respectively.

Results

High basigin-2 expression was associated with lymph-vascular space involvement, lymph node metastasis and poor prognosis of epithelial ovarian cancer. Multivariate analyses indicated that basigin-2 positivity was an independent prognostic factor for PFS (P = 0.006) and OS (P = 0.019), respectively. Overexpression of basigin-2 increased the secretion of MMP-2/9 and cancer cell migration and invasion of HO-8910 cells, whereas knockdown of basigin-2 reduced active MMP-2/9 production, migration and invasion of HO-8910 PM cells.

Conclusions

The expression of basigin-2 might be an independent prognostic marker and basigin-2 inhibition would be a potential strategy for epithelial ovarian cancer patients, especially in inhibiting and preventing cancer cell invasion and metastasis.

Timp1 interacts with beta-1 integrin and CD63 along melanoma genesis and confers anoikis resistance by activating PI3-K signaling pathway independently of Akt phosphorylation

BACKGROUND

Anoikis resistance is one of the abilities acquired along tumor progression. This characteristic is associated with metastasis development, since tumorigenic cells must survive independently of cell-matrix interactions in this process. In our laboratory, it was developed a murine melanocyte malignant transformation model associated with a sustained stressful condition. After subjecting melan-a melanocytes to 1, 2, 3 and 4 cycles of anchorage impediment, anoikis resistant cells were established and named 1C, 2C, 3C and 4C, respectively. These cells showed altered morphology and PMA independent cell growth, but were not tumorigenic, corresponding to pre-malignant cells. After limiting dilution of 4C pre-malignant cells, melanoma cell lines with different characteristics were obtained. Previous data from our group showed that increased Timp1 expression correlated with anoikis-resistant phenotype. Timp1 was shown to confer anchorage-independent growth capability to melan-a melanocytes and render melanoma cells more aggressive when injected into mice. However, the mechanisms involved in anoikis regulation by Timp1 in tumorigenic cells are not clear yet.

METHODS

The β1-integrin and Timp1 expression were evaluated by Western blotting and CD63 protein expression by flow cytometry using specific antibodies. To analyze the interaction among Timp1, CD63 and β1-integrin, immunoprecipitation assays were performed, anoikis resistance capability was evaluated in the presence or not of the PI3-K inhibitors, Wortmannin and LY294002. Relative expression of TIMP1 and CD63 in human metastatic melanoma cells was analyzed by real time PCR.

RESULTS

Differential association among Timp1, CD63 and β1-integrins was observed in melan-a melanocytes, 4C pre-malignant melanocytes and 4C11- and 4C11+ melanoma cells. Timp1 present in conditioned medium of melanoma cells rendered melan-a melanocytes anoikis-resistant through PI3-K signaling pathway independently of Akt activation. In human melanoma cell lines, in which TIMP1 and beta-1 integrin were also found to be interacting, TIMP1 and CD63 levels together was shown to correlate significantly with colony formation capacity.

CONCLUSIONS

Our results show that Timp1 is assembled in a supramolecular complex containing CD63 and β1-integrins along melanoma genesis and confers anoikis resistance by activating PI3-K signaling pathway, independently of Akt phosphorylation. In addition, our data point TIMP1, mainly together with CD63, as a potential biomarker of melanoma.

Discovery of a Series of Thiazole Derivatives as Novel Inhibitors of Metastatic Cancer Cell Migration and Invasion

Effective inhibitors of cancer cell migration and invasion can potentially lead to clinical applications as therapy to block tumor metastasis, the primary cause of death in cancer patients. To this end we have designed and synthesized a series of thiazole derivatives that showed potent efficacy against cell migration and invasion in metastatic cancer cells. The most effective compound, 5k, was found to have an IC₅₀ value of 176 nM in the dose-dependent transwell migration assays in MDA-MB-231cells. At the dose of 10 μM, 5k also blocked about 80% of migration in HeLa and A549 cells and 60% of invasion of MDA-MB-231 cells. Importantly, the majority of the derivatives exhibited no apparent cytotoxicity in the clonogenic assays. The low to negligible inhibition of cell proliferation is a desirable property of these anti-migration derivatives because they hold promise of low toxicity to healthy cells as potential therapeutic agents. Mechanistic studies analyzing the actin cytoskeleton by microscopy demonstrate that compound 5k substantially reduced cellular f-actin, and prevented localization of fascin to actin-rich membrane protrusions. These results suggest that the anti-migration activity may result from impaired actin structures in protrusions that are necessary to drive migration.

The microtubule binding drug EM011 inhibits the growth of paediatric low grade gliomas

Low grade gliomas are a heterogeneous group of tumours representing the most common form of neoplasms in the central nervous system among children. Although gross total resection remains the principal treatment, it is often impractical especially for the resection of tumours within eloquent regions of the brain. Instead Radiotherapy is utilised in such cases, but because of its associated toxicities, it is refrained from use among younger children. These limitations coupled with hypersensitivity and toxicities associated with some commonly used chemotherapeutic agents, have ignited the need to search for safer and more effective treatments for paediatric low grade gliomas. In this study, we investigated the EM011 drug on the growth of two pilocytic and one diffuse paediatric astrocytoma cell lines, using an assortment of cancer assays. We discovered that treatments of low grade gliomas with EM011 abrogated cell viability by inducing a decrease in cell proliferation and an arrest in the S and G2M cell cycle phases, followed by a converse increase in apoptosis in a dose and time dependent manner. The cell migratory and invasion indices, as well as anchorage independent growth in soft agarose, were significantly attenuated. These findings were mechanistically associated with a transient release of AIF, a disruption of microtubule architecture, and a decline in the expression of key genes which drive cancer progression including EGFR, mTORC1, JUN and multiple MMPs. In fact, the activity of MMP2 was also perturbed by EM011. These findings, in conjunction with the insignificant adverse side effects established from other studies, make EM011 an appealing chemotherapeutic agent for the treatment of paediatric low grade gliomas.

Caspase signalling in the absence of apoptosis drives Jnk-dependent invasion

Tumours evolve several mechanisms to evade apoptosis, yet many resected carcinomas show significantly elevated caspase activity. Moreover, caspase activity is positively correlated with tumour aggression and adverse patient outcome. These observations indicate that caspases might have a functional role in promoting tumour invasion and metastasis. Using a Drosophila model of invasion, we show that precise effector caspase activity drives cell invasion without initiating apoptosis. Affected cells express the matrix metalloprotinase Mmp1 and invade by activating Jnk. Our results link Jnk and effector caspase signalling during the invasive process and suggest that tumours under apoptotic stresses from treatment, immune surveillance or intrinsic signals might be induced further along the metastatic cascade.

Suppression of HER-2 via siRNA interference promotes apoptosis and decreases metastatic potential of SKOV‑3 human ovarian carcinoma cells

The aberrant expression of human epidermal growth factor receptor-2 (HER-2) has been detected in ovarian cancer. However, the role of HER-2 in the development of ovarian cancer has not been sufficiently elucidated. The objective of this study was to determine the role of HER-2 in the apoptosis and metastasis of SKOV-3 ovarian cancer cells. SKOV-3 cells were transfected with three double‑stranded small interfering RNA (siRNA) molecules that target HER-2. Various sequences were synthesized by T7 transcription in vitro to select the most effective HER-2‑silencing siRNA. SKOV-3 cells were examined for growth inhibition using the MTT proliferation assay and apoptosis was assessed using flow cytometry and TUNEL assay. The Matrigel basement memebrane matrix was used to assess invasion and chemotactic mobility, as a model of tumor cell metastasis. Western blot analysis was used to detect the expression of matrix metallopeptidase-9 (MMP-9), E-cadherin, N-cadherin and vimentin. siRNA interference in HER-2 resulted in decreased cell proliferation and invasion and increased apoptosis. Western blot analysis demonstrated a marked increase in E-cadherin and MMP-9 and a reduction in N-cadherin and vimentin protein levels in the SKOV-3 cells. The suppression of HER-2 expression resulted in apoptosis and the inhibition of metastasis of SKOV-3 cells. Therefore, the overexpression of the HER-2 gene can enhance the metastatic potential of SKOV-3 cells by increasing the protein levels of MMP-9. Epithelial-mesenchymal transition may be involved in the HER-2 siRNA-induced invasion and migration of SKOV-3 cells. Taken together, these results suggest that HER-2 functions as an oncogene and may thus be an attractive therapeutic target in SKOV-3 ovarian cancer cells.

Human chorionic gonadotropin β induces cell motility via ERK1/2 and MMP-2 activation in human glioblastoma U87MG cells

Human chorionic gonadotropin β (hCGβ) promotes tumorigenesis in a variety of tumors including glioblastoma, breast and prostate cancer cells, etc. However, the involved mechanisms remain elusive. Distinct from the other tumors, glioblastoma is a highly invasive brain tumor; invasion causes high recurrence and mortality. Characterization of hCGβ signaling is to determine therapeutic targets to inhibit invasion and lower recurrence. Through both a stable cell line over-expressing hCGβ and hCGβ standards, we tested hCGβ signaling, migration and invasion in human glioblastoma U87MG cells. ELISA showed that hCGβ secreted into culture medium at an amount of 237.8 ± 7.8 ng/10(7) cells in hCGβ transfected stable cells after the cells were grown for 24 h. Through Western blot and Gelatin zymography, we found that hCGβ standards phosphorylated ERK1/2 and upregulated MMP-2 expression in dose- and time-dependent manners. Meanwhile, overexpressed hCGβ phosphorylated ERK1/2, and upregulated MMP-2 expression and activity, whereas ERK1/2 blocker PD98059 (25 μM) significantly decreased both ERK1/2 and MMP-2 expression and activity. In addition, in the same conditions as the signaling test, hCGβ promoted cell migration and invasion, whereas the PD98059 diminished these effects. These findings demonstrated that hCGβ phosphorylated ERK1/2 upregulating MMP-2 expression and activity leading to cell migration and invasion, suggesting that hCGβ, ERK1/2 and MMP-2 are the potential targets to inhibit glioblastoma invasion.

Viability screen on pediatric low grade glioma cell lines unveils a novel anti-cancer drug of the steroid biosynthesis inhibitor family

Pediatric low grade gliomas are the most common central nervous system tumors and are still incurable among a subset of patients despite current treatment modalities. Steroid biosynthesis occurs in a wide variety of organs including the brain, to mediate an assortment of functions, including a proposed role in the growth of gliomas. Hence, targeting steroid biosynthesis and/or their signaling pathways, is anticipated as an effective approach for treating gliomas. In this study, we investigated whether our chemical library of steroid inhibitors can modulate the growth of pediatric low grade glioma cell lines (Res186, Res259, R286), and subsequently identified a potent inhibitor of 17β-hydroxysteroid dehydrogenase type 3, referred to as DK16, which functions by attenuating cell viability, proliferation, migration/invasion and anchorage independent growth and conversely induces apoptosis and cell cycle arrest in a dose and duration dependent manner. Further investigations into the mechanisms of how DK16 functions showed that this drug increased the BAX/BCL2 expression ratio, induced phosphatidylserine externalization, and mitochondrial membrane depolarizations culminating to the release and nuclear translocation of AIF. In addition, treatments of low grade glioma cell lines with DK16 increased the expression of pro-apoptotic mediators including CDK2 and CTSL1, and with the converse diminished expression of pro-survival and migratory/invasion genes like PRKCA, TERT, MAPK8, MMP1 and MMP2. Our findings collectively demonstrate the potent anti-neoplastic properties of DK16, a steroid biosynthesis inhibitor, on the growth of pediatric low grade gliomas.

The plasma membrane sialidase NEU3 regulates the malignancy of renal carcinoma cells by controlling β1 integrin internalization and recycling

The human plasma membrane sialidase NEU3 is a key enzyme in the catabolism of membrane gangliosides, is crucial in the regulation of cell surface processes, and has been demonstrated to be significantly up-regulated in renal cell carcinomas (RCCs). In this report, we show that NEU3 regulates β1 integrin trafficking in RCC cells by controlling β1 integrin recycling to the plasma membrane and controlling activation of the epidermal growth factor receptor (EGFR) and focal adhesion kinase (FAK)/protein kinase B (AKT) signaling. NEU3 silencing in RCC cells increased the membrane ganglioside content, in particular the GD1a content, and changed the expression of key regulators of the integrin recycling pathway. In addition, NEU3 silencing up-regulated the Ras-related protein RAB25, which directs internalized integrins to lysosomes, and down-regulated the chloride intracellular channel protein 3 (CLIC3), which induces the recycling of internalized integrins to the plasma membrane. In this manner, NEU3 silencing enhanced the caveolar endocytosis of β1 integrin, blocked its recycling and reduced its levels at the plasma membrane, and, consequently, inhibited EGFR and FAK/AKT. These events had the following effects on the behavior of RCC cells: they (a) decreased drug resistance mediated by the block of autophagy and the induction of apoptosis; (b) decreased metastatic potential mediated by down-regulation of the metalloproteinases MMP1 and MMP7; and (c) decreased adhesion to collagen and fibronectin. Therefore, our data identify NEU3 as a key regulator of the β1 integrin-recycling pathway and FAK/AKT signaling and demonstrate its crucial role in RCC malignancy.

Reversing effect of ring finger protein 43 inhibition on malignant phenotypes of human hepatocellular carcinoma

It has been shown that Ring finger protein 43 (RNF43) is overexpressed in colorectal cancer and mediates cancer cell proliferation; however, its role in hepatocellular carcinoma (HCC) remains unknown. In this study, we found that RNF43 was frequently overexpressed in HCCs, and this overexpression was correlated with positive vascular invasion, poor tumor differentiation, and advanced tumor stage. Functional studies showed that knockdown of RNF43 could induce apoptosis and inhibit proliferation, invasion, colony formation, and xenograft growth of HCCs. Microarray-based gene profiling showed a total of 229 genes differentially expressed after RNF43 knockdown, many of which are involved in oncogenic processes such as cell proliferation, cell adhesion, cell motility, cell death, DNA repair, and so on. These results suggest that RNF43 is involved in tumorigenesis and progression of HCCs and that antagonism of RNF43 may be beneficial for HCC treatment.

Clinical imaging of tumor angiogenesis

Angiogenesis is an integral part of tumor growth and invasion. This has led to the emergence of several antiangiogenic therapies and stimulated efforts to accurately evaluate the extent of angiogenesis before and in response to anticancer treatment. The most commonly used approach has been the assessment of new vessel formation in histological samples. However, it is becoming apparent that this is insufficient for a full understanding of tumor physiology and for in vivo guidance of cancer management. Imaging has the potential to provide noninvasive and repeatable assessment of the angiogenic process. Imaging approaches use a variety of modalities and are aimed at either assessment of the functional integrity of tumor vasculature or assessment of its molecular status. This review summarizes the aims and methods of clinical tumor angiogenesis imaging, including present technologies and ones that will be developed within the next 5-10 years.

Assessing the invasive potential of bladder cancer: development and validation of a new preclinical assay

PURPOSE

We developed and validated an electrophysiological method for standardized preclinical assessment of the invasive potential of urothelial carcinoma of the bladder.

MATERIALS AND METHODS

Human UMUC-3, RT-112, HT-1197 and T24/83 bladder urothelial carcinoma cells, and UROtsa benign urothelial cells were co-cultivated with high resistance MDCK-C7 cells seeded below a 0.4 μm pore membrane of an insert to avoid physical contact and cellular migration. Transepithelial electrical resistance in Ω cm(2) across the MDCK-C7 monolayer was measured longitudinally. Invasive potential coefficients were calculated based on the secretion of proteolytic factors by invading cells.

RESULTS

Consistent transepithelial electrical resistance breakdown patterns were reproduced in 14 or more independent samples of each cell line. Coefficients of invasive potential were significantly higher in bladder urothelial carcinoma than UROtsa cells, including a mean ± SD of 1.5 ± 0.32 vs 9.9 ± 4.97 in UMUC-3, 12.5 ± 6.61 in T24/83, 20.5 ± 4.24 in RT-112 and 21.0 ± 5.15 in HT-1197 cells (p <0.001). No correlation was found between the secretion patterns of matrix metalloproteinase-1, 2 and 9, and invasive potential. Stimulation of UROtsa cells with recombinant human epidermal growth factor up-regulated matrix metalloproteinase-9 secretion and significantly increased invasive potential a mean of 1.3 ± 0.22 vs 14.6 ± 3.28 after stimulation with 10 ng/ml epidermal growth factor (p <0.001).

CONCLUSIONS

We developed a highly sensitive translational tool to study the initial process of metastatic spread of urothelial carcinoma of the bladder. The presented electrophysiological invasion assay enables reliable quantification of the invasive potential of bladder urothelial carcinoma cells before physical transmigration. It can be used to identify key molecules for bladder urothelial carcinoma invasion and develop new therapeutic strategies.

Osthole suppresses migration and invasion of A549 human lung cancer cells through inhibition of matrix metalloproteinase-2 and matrix metallopeptidase-9 in vitro

Osthole, a natural compound, may be extracted from Cnidium monnieri and other medicinal plants. Previous studies have shown that osthole has anticancer effects in various human cancer cell lines. There is, however, no available information concerning the effects of osthole on the migration and invasion of human lung cancer cells. In the current study, we used Transwell assays to demonstrate that osthole inhibited the migration and invasion of A549 human lung cancer cells. Western blot analysis revealed that osthole reduced the levels of matrix metalloproteinase-2 (MMP-2) and matrix metallopeptidase-9 (MMP-9) in the A549 human lung cancer cells. Our findings indicate that osthole may have a novel function as an inhibitor of the metastasis of human lung cancer.

Targeting the microenvironment in chronic lymphocytic leukemia offers novel therapeutic options

Chronic lymphocytic leukemia (CLL) cells display features consistent with a defect in apoptosis and exhibit prolonged survival in vivo. Survival of these malignant cells is influenced by interactions with non-leukemic cells located in permissive niches in lymphoid organs. Leukemic cells subvert the normal architecture of the lymphoid organs, recruiting stromal cells, dendritic cells and T lymphocytes, all reported as playing active roles in the survival and proliferation of CLL. The same survival-promoting environment also rescues/protects leukemic cells from cytotoxic therapies, giving way to disease relapse. This review summarizes and discusses current knowledge about the intricate network of soluble and cell-bound signals regulating the life and death of CLL cells in different districts. At the same time, it seeks to hone in on which discrete molecular elements are best suited as targets for treating this still incurable disease.

Effect of the expression of matrix metalloproteases and their tissue inhibitors on survival of patients with resectable colorectal cancer

BACKGROUND

Matrix metalloproteases (MMPs) and their tissue inhibitors (TIMPs) are of crucial importance in the degradation of the stromal connective tissue and basement membrane components. Study of the behavior of these components might help to predict the aggressiveness of tumors.

AIMS

To evaluate the expression and clinical relevance of MMPs and TIMPs for patients with resectable colorectal carcinoma.

METHODS

An immunohistochemical study was performed using tissue arrays and specific antibodies against MMPs-1, 2, 7, 9, 11, 13, and 14, and TIMPs-1, 2 and 3. Determinations were performed in cancer specimens from 104 patients with resectable colorectal cancer. The minimum period of follow-up was 12.5 years for patients without recurrence. To identify specific groups of tumors with distinct expression profiles, the data were analyzed by unsupervised hierarchical cluster analysis.

RESULTS

Expression of MMP-11 by fibroblasts and MMP-13 by tumor cells were associated with poor prognosis. The dendrogram revealed first-order division of tumors into two distinct MMP/TIMP molecular profiles, designated group 1 (n = 50) and group 2 (n = 54). Group 2 was characterized by significantly higher expression of MMP-1, 11, and 13, and TIMP-3.

CONCLUSION

Our results emphasize the prognostic value of MMP-11 and 13 expression in colorectal cancer.

E-cadherin dysfunction in gastric cancer--cellular consequences, clinical applications and open questions

E-cadherin plays a major role in cell-cell adhesion and inactivating germline mutations in its encoding gene predispose to hereditary diffuse gastric cancer. Evidence indicates that aside from its recognized role in early tumourigenesis, E-cadherin is also pivotal for tumour progression, including invasion and metastization. Herein, we discuss E-cadherin alterations found in a cancer context, associated cellular effects and signalling pathways, and we raise new key questions that will impact in the management of GC patients and families.

New and paradoxical roles of matrix metalloproteinases in the tumor microenvironment

Processes such as cell proliferation, angiogenesis, apoptosis, or invasion are strongly influenced by the surrounding microenvironment of the tumor. Therefore, the ability to change these surroundings represents an important property through which tumor cells are able to acquire specific functions necessary for tumor growth and dissemination. Matrix metalloproteinases (MMPs) constitute key players in this process, allowing tumor cells to modify the extracellular matrix (ECM) and release cytokines, growth factors, and other cell-surface molecules, ultimately facilitating protease-dependent tumor progression. Remodeling of the ECM by collagenolytic enzymes such as MMP1, MMP8, MMP13, or the membrane-bound MT1-MMP as well as by other membrane-anchored proteases is required for invasion and recruitment of novel blood vessels. However, the multiple roles of the MMPs do not all fit into a simple pattern. Despite the pro-tumorigenic function of certain metalloproteinases, recent studies have shown that other members of these families, such as MMP8 or MMP11, have a protective role against tumor growth and metastasis in animal models. These studies have been further expanded by large-scale genomic analysis, revealing that the genes encoding metalloproteinases, such as MMP8, MMP27, ADAM7, and ADAM29, are recurrently mutated in specific tumors, while several ADAMTSs are epigenetically silenced in different cancers. The importance of these proteases in modifying the tumor microenvironment highlights the need for a deeper understanding of how stroma cells and the ECM can modulate tumor progression.

Anti-angiogenic drug discovery: lessons from the past and thoughts for the future

INTRODUCTION

Since the pioneering work of Judah Folkman, the discovery of bevacizumab has introduced the use of anti-angiogenic agents as a new modality for the treatment of cancer. Currently, hundreds of clinical trials involving anti-angiogenic agents, targeting different elements of the tumour angiogenesis pathway, are underway. However, thus far, the benefits of anti-angiogenic therapy in unselected patient populations are often marginal with harmful side effects.

AREAS COVERED

This article presents a detailed discussion of the lessons learnt from the use of bevacizumab and other VEGF pathway inhibitors in the clinical setting. Specifically, this article provides a review of the literature on anti-VEGF agents and other angiogenesis inhibitors used in pre-clinical and clinical trials for cancer treatment.

EXPERT OPINION

Future anti-angiogenic drug design centres on multiple protein targets and combinations including: growth factors, hypoxia-inducible factor and tumour endothelial cell markers unique to the tumour vasculature. Furthermore, treatment dosing, scheduling and combination with radiation and chemotherapy require further investigation, as does the potential of treating early disease, and the development of biomarkers which accurately predict response to therapy. These are essential for the future development of these drugs with individualised therapy likely to be the ultimate goal.

Interleukin-1β mediates metalloproteinase-dependent renal cell carcinoma tumor cell invasion through the activation of CCAAT enhancer binding protein β

Effective treatment of metastatic renal cell carcinoma (RCC) remains a major medical concern, as these tumors are refractory to standard therapies and prognosis is poor. Although molecularly targeted therapies have shown some promise in the treatment of this disease, advanced RCC tumors often develop resistance to these drugs. Dissecting the molecular mechanisms underlying the progression to advanced disease is necessary to design alternative and improved treatment strategies. Tumor-associated macrophages (TAMs) found in aggressive RCC tumors produce a variety of inflammatory cytokines, including interleukin-1β (IL-1β). Moreover, the presence of TAMs and high serum levels of IL-1β in RCC patients correlate with advanced disease. We hypothesized that IL-1β in the tumor microenvironment promotes the development of aggressive RCC tumors by directing affecting tumor epithelial cells. To address this, we investigated the role of IL-1β in mediating RCC tumor cell invasion as a measure of tumor progression. We report that IL-1β induced tumor cell invasion of RCC cells through a process that was dependent on the activity of matrix metalloproteinases (MMPs) and was independent of migration rate. Specifically, IL-1β induced the expression of MMP-1, MMP-3, MMP-10, and MT1-MMP in a mechanism dependent on IL-1β activation of the transcription factor CCAAT enhancer binding protein β (CEBPβ). Consistent with its role in MMP gene expression, CEBPβ knockdown significantly reduced invasion, but not migration, of RCC tumor cells. These results identify the IL-1β /CEBPβ/MMP pathway as a putative target in the design of anti-metastatic therapies for the treatment of advanced RCC.