Membrane type I matrix metalloproteinase usurps tumor growth control imposed by the three-dimensional extracellular matrix

Parallel Murine and Human Plaque Proteomics Reveals Pathways of Plaque Rupture

RATIONALE

Plaque rupture is the proximate cause of most myocardial infarctions and many strokes. However, the molecular mechanisms that precipitate plaque rupture are unknown.

OBJECTIVE

By applying proteomic and bioinformatic approaches in mouse models of protease-induced plaque rupture and in ruptured human plaques, we aimed to illuminate biochemical pathways through which proteolysis causes plaque rupture and identify substrates that are cleaved in ruptured plaques.

METHODS AND RESULTS

We performed shotgun proteomics analyses of aortas of transgenic mice with macrophage-specific overexpression of urokinase (SR-uPA^+/0 mice) and of SR-uPA^+/0 bone marrow transplant recipients, and we used bioinformatic tools to evaluate protein abundance and functional category enrichment in these aortas. In parallel, we performed shotgun proteomics and bioinformatics studies on extracts of ruptured and stable areas of freshly harvested human carotid plaques. We also applied a separate protein-analysis method (protein topography and migration analysis platform) to attempt to identify substrates and proteolytic fragments in mouse and human plaque extracts. Approximately 10% of extracted aortic proteins were reproducibly altered in SR-uPA^+/0 aortas. Proteases, inflammatory signaling molecules, as well as proteins involved with cell adhesion, the cytoskeleton, and apoptosis, were increased. ECM (Extracellular matrix) proteins, including basement-membrane proteins, were decreased. Approximately 40% of proteins were altered in ruptured versus stable areas of human carotid plaques, including many of the same functional categories that were altered in SR-uPA^+/0 aortas. Collagens were minimally altered in SR-uPA^+/0 aortas and ruptured human plaques; however, several basement-membrane proteins were reduced in both SR-uPA^+/0 aortas and ruptured human plaques. Protein topography and migration analysis platform did not detect robust increases in proteolytic fragments of ECM proteins in either setting.

CONCLUSIONS

Parallel studies of SR-uPA^+/0 mouse aortas and human plaques identify mechanisms that connect proteolysis with plaque rupture, including inflammation, basement-membrane protein loss, and apoptosis. Basement-membrane protein loss is a prominent feature of ruptured human plaques, suggesting a major role for basement-membrane proteins in maintaining plaque stability.

Cancer associated fibroblast: Mediators of tumorigenesis

It is well accepted that the tumor microenvironment plays a pivotal role in cancer onset, development, and progression. The majority of clinical interventions are designed to target either cancer or stroma cells. These emphases have been directed by one of two prevailing theories in the field, the Somatic Mutation Theory and the Tissue Organization Field Theory, which represent two seemingly opposing concepts. This review proposes that the two theories are mutually inclusive and should be concurrently considered for cancer treatments. Specifically, this review discusses the dynamic and reciprocal processes between stromal cells and extracellular matrices, using pancreatic cancer as an example, to demonstrate the inclusivity of the theories. Furthermore, this review highlights the functions of cancer associated fibroblasts, which represent the major stromal cell type, as important mediators of the known cancer hallmarks that the two theories attempt to explain.

Differential Protein Expression between Cystic and Solid Vestibular Schwannoma Using Tandem Mass Tag-Based Quantitative Proteomic Analysis

PURPOSE

Cystic vestibular schwannoma (CVS) and solid vestibular schwannoma (SVS) are subgroups of vestibular schwannoma (VS). The tumorigenesis of CVS and SVS have not been fully elucidated, and this study is designed to identify differentially expressed proteins involved in the tumorigenesis of CVS and SVS.

EXPERIMENTAL DESIGN

Tandem mass tag-based proteomics is used to determine the protein expression profiles from CVS and SVS tissues.

RESULTS

A total of 30 differentially expressed proteins are identified between CVS and SVS, with 6 being upregulated and 24 being downregulated. Bioinformatics analyses are performed according to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. These results indicate that two selected proteins (COL1A1 and COL1A2) are potential biomarkers for distinguishing CVS and SVS.

CONCLUSIONS AND CLINICAL RELEVANCE

Differentially expressed proteins linked to CVS and SVS are identified, and these proteins might provide potential biomarkers for human VS diagnosis. Furthermore, the present study supports the notion that decreased collagen might be the reason for bleeding associated with CVS.

Epithelial-to-mesenchymal transition and invadopodia markers in breast cancer: Lumican a key regulator

A great hallmark of breast cancer is the absence or presence of estrogen receptors ERα and ERβ, with a dominant role in cell proliferation, differentiation and cancer progression. Both receptors are related with Epithelial-to-Mesenchymal Transition (EMT) since there is a relation between ERs and extracellular matrix (ECM) macromolecules expression, and therefore, cell-cell and cell-ECM interactions. The endocrine resistance of ERα endows epithelial cells with increased aggressiveness and induces cell proliferation, resulting into a mesenchymal phenotype and an EMT status. ERα signaling may affect the transcriptional factors which govern EMT. Knockdown or silencing of ERα and ERβ in MCF-7 and MDA-MB-231 breast cancer cells respectively, provoked pivotal changes in phenotype, cellular functions, mRNA and protein levels of EMT markers, and consequently the EMT status. Mesenchymal cells owe their migratory and invasive properties to invadopodia, while in epithelial cells, lamellipodia and filopodia are mostly observed. Invadopodia, are actin-rich protrusions of plasma membrane, promoting proteolytic degradation of ECM and tumor invasion. Cortactin and MMP-14 govern the formation and principal functions of invadopodia. In vitro experiments proved that lumican inhibits cortactin and MMP-14 expression, alters the formation of lamellipodia and transforms mesenchymal cells into epithelial-like. Conclusively, lumican may inhibit or even reverse the several metastatic features that EMT endows in breast cancer cells. Therefore, a lumican-based anti-cancer therapy which will pharmacologically target and inhibit EMT might be interesting to be developed.

Macromolecular gelatin properties affect fibrin microarchitecture and tumor spheroid behavior in fibrin-gelatin gels

The biophysical properties of extracellular matrices (ECM) are known to regulate cell behavior, however decoupling cell behavior changes due to the relative contributions of material microstructure versus biomechanics or nutrient permeability remains challenging, especially within complex, multi-material matrices. We developed four gelatin-fibrin interpenetrating network (IPN) formulations which are identical in composition but possess variable gelatin molecular weight distributions, and display differences in microstructure, biomechanics, and diffusivity. In this work we interrogate the response of multicellular tumor spheroids to these IPN formulations and found that a high stiffness, gelatin-network dominated IPNs impeded remodeling and invasion of multicellular tumor spheroids; whereas relatively lower stiffness, fibrin-network dominated IPNs permitted protease-dependent remodeling and spheroid invasion. Cell proliferation correlated to nutrient diffusivity across tested IPN formulations. These findings demonstrate the complexity of ECM IPNs, relative to single polymer matrices, and highlight that cell response does not derive from a single aspect of the ECM, but rather from the interplay of multiple biomechanical properties. The methodology developed here represents a framework for future studies which aim to characterize cellular phenotypic responses to biophysical cues present within complex, multi-material matrices.

Discoidin Domain Receptors, DDR1b and DDR2, Promote Tumour Growth within Collagen but DDR1b Suppresses Experimental Lung Metastasis in HT1080 Xenografts

The Discoidin Domain Receptors (DDRs) constitute a unique set of receptor tyrosine kinases that signal in response to collagen. Using an inducible expression system in human HT1080 fibrosarcoma cells, we investigated the role of DDR1b and DDR2 on primary tumour growth and experimental lung metastases. Neither DDR1b nor DDR2 expression altered tumour growth at the primary site. However, implantation of DDR1b- or DDR2-expressing HT1080 cells with collagen I significantly accelerated tumour growth rate, an effect that could not be observed with collagen I in the absence of DDR induction. Interestingly, DDR1b, but not DDR2, completely hindered the ability of HT1080 cells to form lung colonies after intravenous inoculation, suggesting a differential role for DDR1b in primary tumour growth and lung colonization. Analyses of tumour extracts revealed specific alterations in Hippo pathway core components, as a function of DDR and collagen expression, that were associated with stimulation of tumour growth by DDRs and collagen I. Collectively, these findings identified divergent effects of DDRs on primary tumour growth and experimental lung metastasis in the HT1080 xenograft model and highlight the critical role of fibrillar collagen and DDRs in supporting the growth of tumours thriving within a collagen-rich stroma.

Framing cancer progression: influence of the organ- and tumour-specific matrisome

The extracellular matrix (ECM) plays a crucial role in regulating organ homeostasis. It provides mechanical and biochemical cues directing cellular behaviour and, therefore, has control over the progression of diseases such as cancer. Recent efforts have greatly enhanced our knowledge of the protein composition of the ECM and its regulators, the so-called matrisome, in healthy and cancerous tissues; yet, an overview of the common signatures and organ-specific ECM in cancer is missing. Here, we address this by taking a detailed approach to review why cancer grows in certain organs, and focus on the influence of the matrisome at primary and metastatic tumour sites. Our in-depth and comprehensive review of the current literature and general understanding identifies important commonalities and distinctions, providing insight into the biology of metastasis, which could pave the way to improve future diagnostics and therapies.

The pan-therapeutic resistance of disseminated tumor cells: Role of phenotypic plasticity and the metastatic microenvironment

Cancer metastasis is the leading cause of mortality in patients with solid tumors. The majority of these deaths are associated with metastatic disease that occurs after a period of clinical remission, anywhere from months to decades following removal of the primary mass. This dormancy is prominent in cancers of the breast and prostate among others, leaving the survivors uncertain about their longer-term prognosis. The most daunting aspect of this dormancy and re-emergence is that the micrometastases in particular, and even large lethal outgrowths are often show resistance to agents to which they have not been exposed. This suggests that in addition to specific mutations that target single agents, there also exist adaptive mechanisms that provide this pan-resistance. Potential molecular underpinnings of which are the topic of this review.

Versican in the Tumor Microenvironment

Versican is an extracellular matrix proteoglycan with nonredundant roles in diverse biological and cellular processes, ranging from embryonic development to adult inflammation and cancer. Versican is essential for cardiovascular morphogenesis, neural crest migration, and skeletal development during embryogenesis. In the adult, versican acts as an inflammation "amplifier" and regulator of immune cell activation and cytokine production. Increased versican expression has been observed in a wide range of malignant tumors and has been associated with poor patient outcomes. The main sources of versican production in the tumor microenvironment include accessory cells (myeloid cells and stromal components) and, in some contexts, the tumor cells themselves. Versican has been implicated in several classical hallmarks of cancer such as proliferative signaling, evasion of growth suppressor signaling, resistance to cell death, angiogenesis, and tissue invasion and metastasis. More recently, versican has been implicated in escape from tumor immune surveillance, e.g., through dendritic cell dysfunction. Versican's multiple contributions to benign and malignant biological processes are further diversified through the generation of versican-derived bioactive proteolytic fragments (matrikines), with versikine being the most studied to date. Versican and versican-derived matrikines hold promise as targets in the management of inflammatory and malignant conditions as well as in the development of novel predictive and prognostic biomarkers.

Translocating a High-Affinity Designer TIMP-1 to the Cell Membrane for Total Renal Carcinoma Inhibition: Putting the Prion Protein to Good Use

Membrane type 1-matrix metalloproteinase (MT1-MMP) and tumor necrosis factor α (TNF-α)-converting enzyme (TACE) are prominent membrane-anchored metalloproteinases that regulate the turnover of extracellular matrix (ECM) components and bioactive molecules required for cancer proliferation. In this study, we describe a novel approach that would allow tissue inhibitor of metalloproteinase 1 (TIMP-1), the endogenous inhibitor of the matrix metalloproteinases (MMPs), to be translocated to the cell membrane for simultaneous MT1-MMP/TACE inhibition. We achieve this by fusing T1^TACE, a designer TIMP-1 with superb affinities for MT1-MMP and TACE, to the glycosyl-phosphatidyl inositol anchor of prions to create a membrane-tethered, broad-spectrum inhibitor, named T1^{Pr αTACE}, that colocalizes with MT1-MMP and TACE on the cell surface. Transduction of T1^{Pr αTACE} in human fibrosarcoma cells results not only in a substantial reduction in gelatinolytic and TNF-α/heparin binding epithelial growth factor shedding activities but also in a loss of tubulogenic capability in three-dimensional matrices. In renal carcinoma, T1^{Pr αTACE} triggers cellular senescence and disrupts MMP-mediated proteolysis of ECM components such as fibronectin and collagen I, leading to an impairment in cell motility and survival under both in vitro and in vivo conditions. Taken together, our findings may provide a new perspective in TIMP targeting that could be exploited to halt metastatic renal carcinoma progression.

The pharmaceutical multi-activity of metallofullerenol invigorates cancer therapy

Currently, cancer continues to afflict humanity. The direct destruction and killing of tumor cells by surgery, radiation and chemotherapy gives rise to many side effects and compromised efficacy. Encouragingly, the rapid development of nanotechnology offers attractive opportunities to revolutionize the current situation of cancer therapy. Metallofullerenol Gd@C82(OH)22, in contrast to chemotherapeutics that directly kill tumor cells, demonstrates anti-tumor behavior with high efficiency and low toxicity by modulating the tumor microenvironment. Furthermore, Gd@C82(OH)22 has been recently reported to specifically target cancer stem cells. In this review, we give a concise introduction to the development of the fullerene family and then report the anti-tumor activity of Gd@C82(OH)22 based on its unique physicochemical characteristics, followed by a comprehensive summary of the anti-tumor biological mechanisms which target different components of the tumor microenvironment as well as the biodistribution and toxicity of Gd@C82(OH)22. Finally, we describe Gd@C82(OH)22 as a "particulate medicine" to highlight its distinctions from conventional "molecular medicine", with considerable emphasis on the advantages of nanomedicine. The in-depth investigation of Gd@C82(OH)22 undoubtedly provides a constructive reference for the development of other nanomedicines, especially in the fullerene family. The application of nanotechnology in the medical field definitely provides a promising and favorable future for improving the current status of cancer therapy.

Review on biofabrication and applications of heterogeneous tumor models

Resolving the origin and development of tumor heterogeneity has proven to be a crucial challenge in cancer research. In vitro tumor models have been widely used for both scientific and clinical research. Currently, tumor models based on 2D cell culture, animal models, and 3D cell-laden constructs are widely used. Heterogeneous tumor models, which consist of more than one cell type and mimic cell-cell as well as cell-matrix interactions, are attracting increasing attention. Heterogeneous tumor models can serve as pathological models to study the microenvironment and tumor development such as tumorigenesis, invasiveness, and malignancy. They also provide disease models for drug screening and personalized therapy. In this review, the current techniques, models, and oncological applications regarding 3D heterogeneous tumor models are summarized and discussed.

Simple and cost-effective assay for isolating invasive living cells

A modified invasion assay using a three-dimensional collagen gel was developed that enables isolation of invasive living cells; it was named the invading cell trapping (iCT) assay. A small cell strainer consisting of a nylon mesh with 40-μm² pores was used, and collagen gel layers formed across the membrane. Test cells were seeded in the lower gel layer and invasive cells were attracted upward and trapped in the upper gel. After incubation, the collagen gel layers in cell strainers were easily separated and living cells in the gel were counted and analyzed. An advantage of the iCT assay is that it can capture living invasive cells in the upper gel while leaving noninvasive ones in the lower layer. Further enrichment of the two cell populations can be achieved by repeating the assay. Thus, the iCT assay allows comparative analysis of invasive versus noninvasive cells.

Prevention of early liver metastasis after pancreatectomy by perioperative administration of a nuclear factor-κB inhibitor in mice

BACKGROUND

Liver metastasis is a common problem after pancreatectomy for pancreatic cancer. In pancreatic cancer cells, nuclear factor-κB is activated constitutively. Nuclear factor-κB activates matrix metalloproteinase-2/9, which plays an important role in cancer metastasis. Because the serine protease inhibitor FUT-175 suppresses nuclear factor-κB, we hypothesized that perioperative treatment with FUT-175 for pancreatic cancer may help to prevent liver metastasis.

METHODS

We compared in vitro cell viability, cell invasiveness, nuclear factor-κB signaling, and the expression levels of matrix metalloproteinase signals between the control group (C group) and the FUT-175 group (F group) using the murine pancreatic cancer cells PAN02. In addition, we evaluated the in vivo effect of pretreatment with FUT-175 using an established model of liver metastasis in mice. Metastatic liver lesions were assessed with magnetic resonance imaging. Liver recurrence and overall survival were evaluated. Also, the antimetastatic effect of systemic administration of FUT-175 was examined.

RESULTS

FUT-175 did not suppress the cell viability of PAN02 cells at or after 24 hours of treatment (P > .05); however, cell invasion was suppressed in the F group compared with the C group (P < .05). The levels of nuclear factor-κB activation, membrane type-1 (MT-1) matrix metalloproteinase (MMP)/matrix metalloproteinase-14 (MMP-14), and matrix metalloproteinase-2/9 (MMP-2/9) were lower in the F group compared with the C group. In vivo, both disease-free and overall survivals were prolonged in the F group compared with the C group. Systemic administration was also effective in suppressing the number of metastases.

CONCLUSION

Perioperative treatment with FUT-175 may help to prevent early liver metastasis after pancreatectomy for pancreatic cancer.

p63 at the Crossroads between Stemness and Metastasis in Breast Cancer

After lung cancer, breast cancer (BC) is the most frequent cause of cancer death among women, worldwide. Although advances in screening approaches and targeted therapeutic agents have decreased BC incidence and mortality, over the past five years, triple-negative breast cancer (TNBC) remains the breast cancer subtype that displays the worst prognosis, mainly due to the lack of clinically actionable targets. Genetic and molecular profiling has unveiled the high intrinsic heterogeneity of TNBC, with the basal-like molecular subtypes representing the most diffuse TNBC subtypes, characterized by the expression of basal epithelial markers, such as the transcription factor p63. In this review, we will provide a broad picture on the physiological role of p63, in maintaining the basal epithelial identity, as well as its involvement in breast cancer progression, emphasizing its relevance in tumor cell invasion and stemness.

Targeting the tumour stroma to improve cancer therapy

Cancers are not composed merely of cancer cells alone; instead, they are complex 'ecosystems' comprising many different cell types and noncellular factors. The tumour stroma is a critical component of the tumour microenvironment, where it has crucial roles in tumour initiation, progression, and metastasis. Most anticancer therapies target cancer cells specifically, but the tumour stroma can promote the resistance of cancer cells to such therapies, eventually resulting in fatal disease. Therefore, novel treatment strategies should combine anticancer and antistromal agents. Herein, we provide an overview of the advances in understanding the complex cancer cell-tumour stroma interactions and discuss how this knowledge can result in more effective therapeutic strategies, which might ultimately improve patient outcomes.

The Role of Fibrosis and Liver-Associated Fibroblasts in the Pathogenesis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most aggressive types of cancer and lacks effective therapeutic approaches. Most HCC develops in the setting of chronic liver injury, hepatic inflammation, and fibrosis. Hepatic stellate cells (HSCs) and cancer-associated fibroblasts (CAFs) are key players in liver fibrogenesis and hepatocarcinogenesis, respectively. CAFs, which probably derive from HSCs, activate into extracellular matrix (ECM)-producing myofibroblasts and crosstalk with cancer cells to affect tumor growth and invasion. In this review, we describe the different components which form the HCC premalignant microenvironment (PME) and the tumor microenvironment (TME), focusing on the liver fibrosis process and the biology of CAFs. We will describe the CAF-dependent mechanisms which have been suggested to promote hepatocarcinogenesis, such as the alteration of ECM, CAF-dependent production of cytokines and angiogenic factors, CAF-dependent reduction of immuno-surveillance, and CAF-dependent promotion of epithelial-mesenchymal transition (EMT). New knowledge of the fibrosis process and the role of CAFs in HCC may pave the way for new therapeutic strategies for liver cancer.

The Role of Fibrosis and Liver-Associated Fibroblasts in the Pathogenesis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most aggressive types of cancer and lacks effective therapeutic approaches. Most HCC develops in the setting of chronic liver injury, hepatic inflammation, and fibrosis. Hepatic stellate cells (HSCs) and cancer-associated fibroblasts (CAFs) are key players in liver fibrogenesis and hepatocarcinogenesis, respectively. CAFs, which probably derive from HSCs, activate into extracellular matrix (ECM)-producing myofibroblasts and crosstalk with cancer cells to affect tumor growth and invasion. In this review, we describe the different components which form the HCC premalignant microenvironment (PME) and the tumor microenvironment (TME), focusing on the liver fibrosis process and the biology of CAFs. We will describe the CAF-dependent mechanisms which have been suggested to promote hepatocarcinogenesis, such as the alteration of ECM, CAF-dependent production of cytokines and angiogenic factors, CAF-dependent reduction of immuno-surveillance, and CAF-dependent promotion of epithelial-mesenchymal transition (EMT). New knowledge of the fibrosis process and the role of CAFs in HCC may pave the way for new therapeutic strategies for liver cancer.

An in situ hybridization study of MMP-2, -9, -13, -14, TIMP-1, and -2 mRNA in fetal mouse mandibular condylar cartilage as compared with limb bud cartilage

The main purpose of this in situ hybridization study was to investigate MMPs and TIMPs mRNA expression in developing mandibular condylar cartilage and limb bud cartilage. At E14.0, MMP-2, -14, TIMP-1 and -2 mRNAs were expressed in the periosteum of mandibular bone, and in the condylar anlage. At E15.0 MMP-2, -14, TIMP-1 and -2 mRNAs were expressed in the perichondrium of newly formed condylar cartilage and the periosteum of developing bone collar, whereas, expression of MMP-14 and TIMP-1 mRNAs were restricted to the inner layer of the periosteum/perichondrium. This expression patterns continued until E18.0. Further, from E13.0 to 14.0, in the developing tibial cartilage, MMP-2, -14, and TIMP-2 mRNAs were expressed in the periosteum/perichondrium, but weak MMP-14 and no TIMP-1 mRNA expression was recognized in the perichondrium. These results confirmed that the perichondrium of condylar cartilage has characteristics of periosteum, and suggested that MMPs and/or TIMPs are more actively involved in the development of condylar (secondary) cartilage than tibial (primary) cartilage. MMP-9-positive cells were observed in the bone collar of both types of cartilage, and they were consistent with osteoclasts/chondroclasts. MMP-13 mRNA expression was restricted to the chondrocytes of the lower hypertrophic cell zone in tibial cartilage at E14.0, indicating MMP-13 can be used as a marker for lower hypertrophic cell zone. It was also expressed in chondrocytes of newly formed condylar cartilage at E15.0, and continuously expressed in the lower hypertrophic cell zone until E18.0. These results confirmed that progenitor cells of condylar cartilage are rapidly differentiated into hypertrophic chondrocytes, which is a unique structural feature of secondary cartilage different from that of primary cartilage.

Targeting a Designer TIMP-1 to the Cell Surface for Effective MT1-MMP Inhibition: A Potential Role for the Prion Protein in Renal Carcinoma Therapy

Renal carcinoma cells express Membrane Type 1-Matrix Metalloproteinase (MT1-MMP, MMP-14) to degrade extracellular matrix components and a range of bioactive molecules to allow metastasis and cell proliferation. The activity of MT1-MMP is modulated by the endogenous inhibitors, Tissue Inhibitor of Metalloproteinases (TIMPs). In this study, we describe a novel strategy that would enable a "designer" TIMP-1 tailored specifically for MT1-MMP inhibition (V4A/P6V/T98L; K_i^app 1.66 nM) to be targeted to the plasma membrane for more effective MT1-MMP inhibition. To achieve this, we fuse the designer TIMP-1 to the glycosyl-phosphatidyl inositol (GPI) anchor of the prion protein to create a membrane-tethered, high-affinity TIMP variant named "T1^{Pr αMT1}" that is predominantly located on the cell surface and co-localised with MT1-MMP. Confocal microscopy shows that T1^{Pr αMT1} is found throughout the cell surface in particular the membrane ruffles where MT1-MMP is most abundant. Expression of T1^{Pr αMT1} brings about a complete abrogation of the gelatinolytic activity of cellular MT1-MMP in HT1080 fibrosarcoma cells whilst in renal carcinoma cells CaKi-1, the GPI-TIMP causes a disruption in MMP-mediated proteolysis of ECM components such as fibronectin, collagen I and laminin that consequently triggers a downstream senescence response. Moreover, the transduced cells also suffer from an impairment in proliferation and survival in vitro as well as in NOD/SCID mouse xenograft. Taken together, our findings demonstrate that the GPI anchor of prion could be exploited as a targeting device in TIMP engineering for MT1-MMP inhibition with a potential in renal carcinoma therapy.

Design, synthesis and biological evaluation of bifunctional inhibitors of membrane type 1 matrix metalloproteinase (MT1-MMP)

Collagen degradation and proMMP-2 activation are major functions of MT1-MMP to promote cancer cell invasion. Since both processes require MT1-MMP homodimerization on the cell surface, herein we propose that the use of bifunctional inhibitors of this enzyme could represent an innovative approach to efficiently reduce tumor growth. A small series of symmetrical dimers derived from previously described monomeric arylsulfonamide hydroxamates was synthesized and tested in vitro on isolated MMPs. A nanomolar MT1-MMP inhibitor, compound 6, was identified and then submitted to cell-based assays on HT1080 fibrosarcoma cells. Dimer 6 reduced MT1-MMP-dependent proMMP-2 activation, collagen degradation and collagen invasion in a dose-dependent manner with better results even compared to its monomeric analogue 4. This preliminary study suggests that dimeric MT1-MMP inhibitors might be further developed and exploited as an alternative tool to reduce cancer cell invasion.

The Precise Diagnosis of Cancer Invasion/Metastasis via 2D Laser Ablation Mass Mapping of Metalloproteinase in Primary Cancer Tissue

Cancer invasion and metastasis remain the major causes of over 90% of patient deaths. Molecular imaging methods such as computed tomography (CT)/magnetic resonance imaging (MRI) can precisely assess primary regional lymph node invasion and distant organ metastasis via body scanning; however, such diagnostic methods are often utilized too late for cancer therapy. To date, pathologic methods mainly provide information on differentiation/proliferation and potential drug therapy biomarkers of primary tumors rather than precisely reveal tumor regional invasion and distant metastasis in the body. We hypothesized that quantification of membrane type-1 matrix metalloproteinase (MT1-MMP) levels in primary tumor tissue will provide a precise assessment of tumor regional lymph node invasion and remote organ metastasis. In this work, we developed peptide-coated Au clusters with intrinsic red fluorescence and a specific mass signal. When these clusters labeled MT1-MMP in tumor tissue sections derived from the xenograft lung carcinoma model, human lung carcinoma and human renal carcinoma, we could directly observe MT1-MMP via optical fluorescence microscopy and quantitatively detect the MT1-MMP expression level via laser ablation inductively coupled plasma mass spectrometry 2D mapping (2D-LA-Mass Mapping). By observing and quantifying the MT1-MMP expression level in primary human lung carcinoma and human renal carcinoma tissue sections, we precisely assessed the risk of primary tumor invasion/metastasis. Importantly, the accuracy of this pathologic method was verified by CT/MRI molecular imaging of cancer patients and traditional hematoxylin and eosin (H&E) staining/immunohistochemistry (IHC)/immunofluorescence (IF) pathologic studies of primary tumor tissues.

Quantitative Method to Track Proteolytic Invasion in 3D Collagen

Since many tumors are associated with a pronounced collagen-rich stromal reaction, there is increasing interest in understanding mechanisms by which cancer cells invade through the collagen barrier. Here we describe a quantitative method to track cell invasion in 3D collagen I gels. We analyze invasion by quantifying proteolytic tracks generated by invading cancer cells through a 3D collagen microenvironment. We provide a detailed protocol for this quantitative assay, which can be used to characterize signaling pathways that regulate invasion in the 3D microenvironment.

Chemical Tools for Selective Activity Profiling of Endogenously Expressed MMP-14 in Multicellular Models

Matrix metalloproteases (MMPs) are a large family of zinc-dependent endopeptidases involved in a diverse set of physiological and pathological processes, most notably in cancer. Current methods for imaging and quantifying MMP activity lack sufficient selectivity and spatiotemporal resolution to allow studies of specific MMP function in vivo. Previously, we reported a strategy for selective targeting of MMPs by engineering a functionally silent cysteine mutation that enables highly specific covalent modification by a designed activity-based probe. Here, we describe the translation of that technology into a mouse model of breast cancer and subsequent demonstration of the utility of the approach for studies of MMP-14 activation in the tumor microenvironment. Using this approach, we find that MMP-14 is active in late stage tumors and is predominantly associated with stromal cell populations that have been activated by specific signaling molecules (e.g., TGFβ) produced by tumor cells. Our data demonstrate the applicability of this approach for studies of MMP function in whole organisms and identify important regulatory mechanisms for MMP-14 activity in the tumor microenvironment.

MMP14 Regulates Cranial Neural Crest Epithelial-to-Mesenchymal Transition and Migration

BACKGROUND

Neural crest is a vertebrate specific cell population. Induced at lateral borders of the neural plate, neural crest cells (NCCs) subsequently undergo epithelial-to-mesenchymal transition (EMT) to detach from the neuroepithelium before migrating into various locations in the embryo. Despite the wealth of knowledge of transcription factors involved in this process, little is known about the effectors that directly regulate neural crest EMT and migration.

RESULTS

Here, we examined the activity of matrix metalloproteinase MMP14 in NCCs and found that MMP14 is expressed in both premigratory and migrating NCCs. Overexpression of MMP14 led to premature migration of NCCs, while down-regulation of MMP14 resulted in reduced neural crest migration. Transplantation experiment further showed that MMP14 is required in NCCs, whereas MMP2, which can be activated by MMP14, is required in the surrounding mesenchyme. in vitro explant culture showed that MMP14 is required for neural crest EMT but not for spreading. This is possibly mediated by the changes in cadherin levels, as decreasing MMP14 level led to increased cadherin expression and increasing MMP14 level led to reduced cadherin expression.

CONCLUSIONS

The results demonstrate that MMP14 is critical for neural crest EMT and migration, partially through regulating the levels of cadherins. Developmental Dynamics 247:1083-1092, 2018. © 2018 Wiley Periodicals, Inc.

The Extracellular Matrix and Pancreatic Cancer: A Complex Relationship

Pancreatic ductal adenocarcinoma (PDAC) has an extraordinarily dense fibrotic stroma that impedes tumor perfusion and delivery of anticancer drugs. Since the extracellular matrix (ECM) comprises the bulk of the stroma, it is primarily responsible for the increased interstitial tissue pressure and stiff mechanical properties of the stroma. Besides its mechanical influence, the ECM provides important biochemical and physical cues that promote survival, proliferation, and metastasis. By serving as a nutritional source, the ECM also enables PDAC cells to survive under the nutrient-poor conditions. While therapeutic strategies using stroma-depleting drugs have yielded disappointing results, an increasing body of research indicates the ECM may offer a variety of potential therapeutic targets. As preclinical studies of ECM-targeted drugs have shown promising effects, a number of clinical trials are currently investigating agents with the potential to advance the future treatment of PDAC. Thus, the present review seeks to give an overview of the complex relationship between the ECM and PDAC.

Hypoxia promotes breast cancer cell invasion through HIF-1α-mediated up-regulation of the invadopodial actin bundling protein CSRP2

Hypoxia is a common feature of solid tumours that promotes invasion and metastatic dissemination. Invadopodia are actin-rich membrane protrusions that direct extracellular matrix proteolysis and facilitate tumour cell invasion. Here, we show that CSRP2, an invadopodial actin bundling protein, is upregulated by hypoxia in various breast cancer cell lines, as well as in pre-clinical and clinical breast tumour specimens. We functionally characterized two hypoxia responsive elements within the proximal promoter of CSRP2 gene which are targeted by hypoxia-inducible factor-1 (HIF-1) and required for promoter transactivation in response to hypoxia. Remarkably, CSRP2 knockdown significantly inhibits hypoxia-stimulated invadopodium formation, ECM degradation and invasion in MDA-MB-231 cells, while CSRP2 forced expression was sufficient to enhance the invasive capacity of HIF-1α-depleted cells under hypoxia. In MCF-7 cells, CSRP2 upregulation was required for hypoxia-induced formation of invadopodium precursors that were unable to promote ECM degradation. Collectively, our data support that CSRP2 is a novel and direct cytoskeletal target of HIF-1 which facilitates hypoxia-induced breast cancer cell invasion by promoting invadopodia formation.

HRS-WASH axis governs actin-mediated endosomal recycling and cell invasion

Transmembrane proteins in the sorting endosome are either recycled to their point of origin or destined for lysosomal degradation. Lysosomal sorting is mediated by interaction of ubiquitylated transmembrane proteins with the endosomal sorting complex required for transport (ESCRT) machinery. In this study, we uncover an alternative role for the ESCRT-0 component hepatocyte growth factor-regulated tyrosine kinase substrate (HRS) in promoting the constitutive recycling of transmembrane proteins. We find that endosomal localization of the actin nucleating factor Wiscott-Aldrich syndrome protein and SCAR homologue (WASH) requires HRS, which occupies adjacent endosomal subdomains. Depletion of HRS results in defective constitutive recycling of epidermal growth factor receptor and the matrix metalloproteinase MT1-MMP, leading to their accumulation in internal compartments. We show that direct interactions with endosomal actin are required for efficient recycling and use a model system of chimeric transferrin receptor trafficking to show that an actin-binding motif can counteract an ubiquitin signal for lysosomal sorting. Directed receptor recycling is used by cancer cells to achieve invasive migration. Accordingly, abrogating HRS- and actin-dependent MT1-MMP recycling results in defective matrix degradation and invasion of triple-negative breast cancer cells.

Age-related modifications of type I collagen impair DDR1-induced apoptosis in non-invasive breast carcinoma cells

Type I collagen and DDR1 axis has been described to decrease cell proliferation and to initiate apoptosis in non-invasive breast carcinoma in three-dimensional cell culture matrices. Moreover, MT1-MMP down-regulates these effects. Here, we address the effect of type I collagen aging and MT1-MMP expression on cell proliferation suppression and induced-apoptosis in non-invasive MCF-7 and ZR-75-1 breast carcinoma. We provide evidence for a decrease in cell growth and an increase in apoptosis in the presence of adult collagen when compared to old collagen. This effect involves a differential activation of DDR1, as evidenced by a higher DDR1 phosphorylation level in adult collagen. In adult collagen, inhibition of DDR1 expression and kinase function induced an increase in cell growth to a level similar to that observed in old collagen. The impact of aging on the sensitivity of collagen to MT1-MMP has been reported recently. We used the MT1-MMP expression strategy to verify whether, by degrading adult type I collagen, it could lead to the same phenotype observed in old collagen 3D matrix. MT1-MMP overexpression abrogated the proliferation suppression and induced-apoptosis effects only in the presence of adult collagen. This suggests that differential collagen degradation by MT1-MMP induced a structural disorganization of adult collagen and inhibits DDR1 activation. This could in turn impair DDR1-induced cell growth suppression and apoptosis. Taken together, our data suggest that modifications of collagen structural organization, due to aging, contribute to the loss of the growth suppression and induced apoptosis effect of collagen in luminal breast carcinoma. MT1-MMP-dependent degradation and aging of collagen have no additive effects on these processes.

Fibroblasts in the Tumor Microenvironment: Shield or Spear?

Tumorigenesis is a complex process involving dynamic interactions between malignant cells and their surrounding stroma, including both the cellular and acellular components. Within the stroma, fibroblasts represent not only a predominant cell type, but also a major source of the acellular tissue microenvironment comprising the extracellular matrix (ECM) and soluble factors. Normal fibroblasts can exert diverse suppressive functions against cancer initiating and metastatic cells via direct cell-cell contact, paracrine signaling by soluble factors, and ECM integrity. The loss of such suppressive functions is an inherent step in tumor progression. A tumor cell-induced switch of normal fibroblasts into cancer-associated fibroblasts (CAFs), in turn, triggers a range of pro-tumorigenic signals accompanied by distraction of the normal tissue architecture, thus creating an optimal niche for cancer cells to grow extensively. To further support tumor progression and metastasis, CAFs secrete factors such as ECM remodeling enzymes that further modify the tumor microenvironment in combination with the altered adhesive forces and cell-cell interactions. These paradoxical tumor suppressive and promoting actions of fibroblasts are the focus of this review, highlighting the heterogenic molecular properties of both normal and cancer-associated fibroblasts, as well as their main mechanisms of action, including the emerging impact on immunomodulation and different therapy responses.

A RAB35-p85/PI3K axis controls oscillatory apical protrusions required for efficient chemotactic migration

How cells move chemotactically remains a major unmet challenge in cell biology. Emerging evidence indicates that for interpreting noisy, shallow gradients of soluble cues a system must behave as an excitable process. Here, through an RNAi-based, high-content screening approach, we identify RAB35 as necessary for the formation of growth factors (GFs)-induced waves of circular dorsal ruffles (CDRs), apically restricted actin-rich migratory protrusions. RAB35 is sufficient to induce recurrent and polarized CDRs that travel as propagating waves, thus behaving as an excitable system that can be biased to control cell steering. Consistently, RAB35 is essential for promoting directed chemotactic migration and chemoinvasion of various cells in response to gradients of motogenic GFs. Molecularly, RAB35 does so by directly regulating the activity of p85/PI3K polarity axis. We propose that RAB35 is a molecular determinant for the control of an excitable, oscillatory system that acts as a steering wheel for GF-mediated chemotaxis and chemoinvasion.

Circular dorsal ruffles (CDRs) are apical actin enriched structures involved in the interpretation of growth factor gradients during cell migration. Here, the authors find that a RAB35/PI3K axis is necessary and sufficient for the formation and stabilization of polarized CDRs and persistent directional migration.

Matrix metalloproteinases in emphysema

Several studies have implicated a causative role for specific matrix metalloproteinases (MMPs) in the development and progression of cigarette smoke-induced chronic obstructive pulmonary disease (COPD) and its severe sequela, emphysema. However, the precise function of any given MMP in emphysema remains an unanswered question. Emphysema results from the degradation of alveolar elastin - among other possible mechanisms - a process that is often thought to be caused by elastolytic proteinases made by macrophages. In this article, we discuss the data suggesting, supporting, or refuting causative roles of macrophage-derived MMPs, with a focus on MMPs-7, -9, -10, -12, and 28, in both the human disease and mouse models of emphysema. Findings from experimental models suggest that some MMPs, such as MMP-12, may directly breakdown elastin, whereas others, particularly MMP-10 and MMP-28, promote the development of emphysema by influencing the proteolytic and inflammatory activities of macrophages.

The role of Tks adaptor proteins in invadopodia formation, growth and metastasis of melanoma

Metastatic cancer cells are characterized by their ability to degrade and invade through extracellular matrix. We previously showed that the Tks adaptor proteins, Tks4 and Tks5, are required for invadopodia formation and/or function in Src-transformed fibroblasts and a number of human cancer cell types. In this study, we investigated the role of Tks adaptor proteins in melanoma cell invasion and metastasis. Knockdown of either Tks4 or Tks5 in both mouse and human melanoma cell lines resulted in a decreased ability to form invadopodia and degrade extracellular matrix. In addition, Tks-knockdown melanoma cells had decreased proliferation in a 3-dimensional type l collagen matrix, but not in 2-dimensional culture conditions. We also investigated the role of Tks proteins in melanoma progression in vivo using xenografts and experimental metastasis assays. Consistent with our in vitro results, reduction of Tks proteins markedly reduced subcutaneous melanoma growth as well as metastatic growth in the lung. We explored the clinical relevance of Tks protein expression in human melanoma specimens using a tissue microarray. Compared to non-malignant nevi, both Tks proteins were highly expressed in melanoma tissues. Moreover, metastatic melanoma cases showed higher expression of Tks5 than primary melanoma cases. Taken together, these findings suggest the importance of Tks adaptor proteins in melanoma growth and metastasis in vivo, likely via functional invadopodia formation.

Solvent water interactions within the active site of the membrane type I matrix metalloproteinase

Matrix metalloproteinases (MMP) are an important family of proteases which catalyze the degradation of extracellular matrix components. While the mechanism of peptide cleavage is well established, the process of enzyme regeneration, which represents the rate limiting step of the catalytic cycle, remains unresolved. This step involves the loss of the newly formed N-terminus (amine) and C-terminus (carboxylate) protein fragments from the site of catalysis coupled with the inclusion of one or more solvent waters. Here we report a novel crystal structure of membrane type I MMP (MT1-MMP or MMP-14), which includes a small peptide bound at the catalytic Zn site via its C-terminus. This structure models the initial product state formed immediately after peptide cleavage but before the final proton transfer to the bound amine; the amine is not present in our system and as such proton transfer cannot occur. Modeling of the protein, including earlier structural data of Bertini and coworkers [I. Bertini, et al., Angew. Chem., Int. Ed., 2006, 45, 7952-7955], suggests that the C-terminus of the peptide is positioned to form an H-bond network to the amine site, which is mediated by a single oxygen of the functionally important Glu240 residue, facilitating efficient proton transfer. Additional quantum chemical calculations complemented with magneto-optical and magnetic resonance spectroscopies clarify the role of two additional, non-catalytic first coordination sphere waters identified in the crystal structure. One of these auxiliary waters acts to stabilize key intermediates of the reaction, while the second is proposed to facilitate C-fragment release, triggered by protonation of the amine. Together these results complete the enzymatic cycle of MMPs and provide new design criteria for inhibitors with improved efficacy.

Directed Evolution to Engineer Monobody for FRET Biosensor Assembly and Imaging at Live-Cell Surface

Monitoring enzymatic activities at the cell surface is challenging due to the poor efficiency of transport and membrane integration of fluorescence resonance energy transfer (FRET)-based biosensors. Therefore, we developed a hybrid biosensor with separate donor and acceptor that assemble in situ. The directed evolution and sequence-function analysis technologies were integrated to engineer a monobody variant (PEbody) that binds to R-phycoerythrin (R-PE) dye. PEbody was used for visualizing the dynamic formation/separation of intercellular junctions. We further fused PEbody with the enhanced CFP and an enzyme-specific peptide at the extracellular surface to create a hybrid FRET biosensor upon R-PE capture for monitoring membrane-type-1 matrix metalloproteinase (MT1-MMP) activities. This biosensor revealed asymmetric distribution of MT1-MMP activities, which were high and low at loose and stable cell-cell contacts, respectively. Therefore, directed evolution and rational design are promising tools to engineer molecular binders and hybrid FRET biosensors for monitoring molecular regulations at the surface of living cells.

Tks adaptor proteins at a glance

Tyrosine kinase substrate (Tks) adaptor proteins are considered important regulators of various physiological and/or pathological processes, particularly cell migration and invasion, and cancer progression. These proteins contain PX and SH3 domains, and act as scaffolds, bringing membrane and cellular components in close proximity in structures known as invadopodia or podosomes. Tks proteins, analogous to the related proteins p47phox, p40phox and NoxO1, also facilitate local generation of reactive oxygen species (ROS), which aid in signaling at invadopodia and/or podosomes to promote their activity. As their name suggests, Tks adaptor proteins are substrates for tyrosine kinases, especially Src. In this Cell Science at a Glance article and accompanying poster, we discuss the known structural and functional aspects of Tks adaptor proteins. As the science of Tks proteins is evolving, this article will point out where we stand and what still needs to be explored. We also underscore pathological conditions involving these proteins, providing a basis for future research to develop therapies for treatment of these diseases.

The store-operated calcium channels in cancer metastasis: from cell migration, invasion to metastatic colonization

Store-operated calcium entry (SOCE) is the predominant calcium entry mechanism in most cancer cells. SOCE is mediated by the endoplasmic reticulum calcium sensor STIMs (STIM1 and 2) and plasma membrane channel forming unit Orais (Orai 1-3). In recent years there is increasing evidence indicating that SOCE in cancer cells is dysregulated to promote cancer cell migration, invasion and metastasis. The overexpression of STIM and Orai proteins has been reported to correlate with the metastatic progression of various cancers. The hyperactive SOCE may promote metastatic dissemination and colonization by reorganizing the actin cytoskeleton, degrading the extracellular matrix and remodeling the tumor microenvironment. Here we discuss how these recent progresses provide novel insights to our understanding of tumor metastasis.

Development of a specific affinity-matured exosite inhibitor to MT1-MMP that efficiently inhibits tumor cell invasion in vitro and metastasis in vivo

The membrane-associated matrix metalloproteinase-14, MT1-MMP, has been implicated in pericellular proteolysis with an important role in cellular invasion of collagenous tissues. It is substantially upregulated in various cancers and rheumatoid arthritis, and has been considered as a potential therapeutic target. Here, we report the identification of antibody fragments to MT1-MMP that potently and specifically inhibit its cell surface functions. Lead antibody clones displayed inhibitory activity towards pro-MMP-2 activation, collagen-film degradation and gelatin-film degradation, and were shown to bind to the MT1-MMP catalytic domain outside the active site cleft, inhibiting binding to triple helical collagen. Affinity maturation using CDR3 randomization created a second generation of antibody fragments with dissociation constants down to 0.11 nM, corresponding to an improved affinity of 332-fold with the ability to interfere with cell-surface MT1-MMP functions, displaying IC₅₀ values down to 5 nM. Importantly, the new inhibitors were able to inhibit collagen invasion by tumor-cells in vitro and in vivo primary tumor growth and metastasis of MDA-MB-231 cells in a mouse orthotopic xenograft model. Herein is the first demonstration that an inhibitory antibody targeting sites outside the catalytic cleft of MT1-MMP can effectively abrogate its in vivo activity during tumorigenesis and metastasis.

Actomyosin contractility and RhoGTPases affect cell-polarity and directional migration during haptotaxis

Although much is known about chemotaxis- induced by gradients of soluble chemical cues - the molecular mechanisms involved in haptotaxis (migration induced by substrate-bound protein gradients) are largely unknown. We used micropatterning to produce discontinuous gradients consisting of μm-sized fibronectin-dots arranged at constant lateral but continuously decreasing axial spacing. Parameters like gradient slope, protein concentration and size or shape of the fibronectin dots were modified to determine optimal conditions for directional cell migration in gradient patterns. We demonstrate that fibroblasts predominantly migrate uphill towards a higher fibronectin density in gradients with a dot size of 2 × 2 μm, a 2% and 6% slope, and a low fibronectin concentration of 1 μg ml^-1. Increasing dot size to 3.5 × 3.5 μm resulted in stationary cells, whereas rectangular dots (2 × 3 μm) orientated perpendicular to the gradient axis preferentially induce lateral migration. During haptotaxis, the Golgi apparatus reorients to a posterior position between the nucleus and the trailing edge. Using pharmacological inhibitors, we demonstrate that actomyosin contractility and microtubule dynamics are a prerequisite for gradient recognition indicating that asymmetric intracellular forces are necessary to read the axis of adhesive gradients. In the haptotaxis signalling cascade, RhoA and Cdc42, and the atypical protein kinase C zeta (aPKCζ), but not Rac, are located upstream of actomyosin contractility.

Organelle Specific O-Glycosylation Drives MMP14 Activation, Tumor Growth, and Metastasis

Cancers grow within tissues through molecular mechanisms still unclear. Invasiveness correlates with perturbed O-glycosylation, a covalent modification of cell-surface proteins. Here, we show that, in human and mouse liver cancers, initiation of O-glycosylation by the GALNT glycosyl-transferases increases and shifts from the Golgi to the endoplasmic reticulum (ER). In a mouse liver cancer model, expressing an ER-targeted GALNT1 (ER-G1) massively increased tumor expansion, with median survival reduced from 23 to 10 weeks. In vitro cell growth was unaffected, but ER-G1 strongly enabled matrix degradation and tissue invasion. Unlike its Golgi-localized counterpart, ER-G1 glycosylates the matrix metalloproteinase MMP14, a process required for tumor expansion. Together, our results indicate that GALNTs strongly promote liver tumor growth after relocating to the ER.

Matrix metalloproteinase collagenolysis in health and disease

The proteolytic processing of collagen (collagenolysis) is critical in development and homeostasis, but also contributes to numerous pathologies. Mammalian interstitial collagenolytic enzymes include members of the matrix metalloproteinase (MMP) family and cathepsin K. While MMPs have long been recognized for their ability to catalyze the hydrolysis of collagen, the roles of individual MMPs in physiological and pathological collagenolysis are less defined. The use of knockout and mutant animal models, which reflect human diseases, has revealed distinct collagenolytic roles for MT1-MMP and MMP-13. A better understanding of temporal and spatial collagen processing, along with the knowledge of the specific MMP involved, will ultimately lead to more effective treatments for cancer, arthritis, cardiovascular conditions, and infectious diseases. This article is part of a Special Issue entitled: Matrix Metalloproteinases edited by Rafael Fridman.

Ensnaring membrane type 1-matrix metalloproteinase (MT1-MMP) with tissue inhibitor of metalloproteinase (TIMP)-2 using the haemopexin domain of the protease as a carrier: a targeted approach in cancer inhibition

Metastatic cancer cells express Membrane Type 1-Matrix Metalloproteinase (MT1-MMP) to degrade the extracellular matrix in order to facilitate migration and proliferation. Tissue Inhibitor of Metalloproteinase (TIMP)-2 is the endogenous inhibitor of the MMP. Here, we describe a novel and highly effective fusion strategy to enhance the delivery of TIMP-2 to MT1-MMP. We can reveal that TIMP-2 fused to the haemopexin +/− transmembrane domains of MT1-MMP (two chimeras named T2^PEX+TM and T2^PEX) are able to interact with MT1-MMP on the cell surface as well as intracellularly. In the case of T2^PEX+TM, there is even a clear sign of MT1-MMP:T2^PEX+TM aggregation by the side of the nucleus to form aggresomes. In vitro, T2^PEX+TM and T2^PEX suppress the gelatinolytic and invasive abilities of cervical carcinoma (HeLa) and HT1080 fibrosarcoma cancer cells significantly better than wild type TIMP-2. In mouse xenograft, we further demonstrate that T2^PEX diminishes cervical carcinoma growth by 85% relative to the control. Collectively, our findings indicate the effectiveness of the fusion strategy as a potential targeted approach in cancer inhibition.

Role of the extracellular matrix in cancer-associated epithelial to mesenchymal transition phenomenon

The epithelial to mesenchymal transition (EMT) program is a crucial component in the processes of morphogenesis and embryonic development. The transition of epithelial to mesenchymal phenotype is associated with numerous structural and functional changes, including loss of cell polarity and tight cell-cell junctions, the acquisition of invasive abilities, and the expression of mesenchymal proteins. The switch between the two phenotypes is involved in human pathology and is crucial for cancer progression. Extracellular matrices (ECMs) are multi-component networks that surround cells in tissues. These networks are obligatory for cell survival, growth, and differentiation as well as tissue organization. Indeed, the ECM suprastructure, in addition to its supportive role, can process and deliver a plethora of signals to cells, which ultimately regulate their behavior. Importantly, the ECM derived signals are critically involved in the process of EMT during tumorigenesis. This review discusses the multilayer interaction between the ECM and the EMT process, focusing on contributions of discrete mediators, a strategy that may identify novel potential target molecules. Developmental Dynamics 247:368-381, 2018. © 2017 Wiley Periodicals, Inc.

Lumican delays melanoma growth in mice and drives tumor molecular assembly as well as response to matrix-targeted TAX2 therapeutic peptide

Lumican is a small leucine-rich proteoglycan (SLRP) being known as a key regulator of collagen fibrillogenesis. However, little attention has been given so far in studying its influence on tumor-associated matrix architecture. Here, we investigate the role of host lumican on tumor matrix organization as well as on disease progression considering an immunocompetent model of melanoma implanted in Lum ^-/- vs. wild type syngeneic mice. Conjointly, lumican impact on tumor response to matrix-targeted therapy was evaluated considering a previously validated peptide, namely TAX2, that targets matricellular thrombospondin-1. Analysis of available genomics and proteomics databases for melanoma first established a correlation between lumican expression and patient outcome. In the B16 melanoma allograft model, endogenous lumican inhibits tumor growth and modulates response to TAX2 peptide. Indeed, IHC analyses revealed that lumican deficiency impacts intratumoral distribution of matricellular proteins, growth factor and stromal cells. Besides, innovative imaging approaches helped demonstrating that lumican host expression drives biochemical heterogeneity of s.c. tumors, while modulating intratumoral collagen deposition as well as organization. Altogether, the results obtained present lumican as a strong endogenous inhibitor of tumor growth, while identifying for the first time this proteoglycan as a major driver of tumor matrix coherent assembly.

Microfluidics Enabled Bottom-Up Engineering of 3D Vascularized Tumor for Drug Discovery

Development of high-fidelity three-dimensional (3D) models to recapitulate the tumor microenvironment is essential for studying tumor biology and discovering anticancer drugs. Here we report a method to engineer the 3D microenvironment of human tumors, by encapsulating cancer cells in the core of microcapsules with a hydrogel shell for miniaturized 3D culture to obtain avascular microtumors first. The microtumors are then used as the building blocks for assembling with endothelial cells and other stromal cells to create macroscale 3D vascularized tumor. Cells in the engineered 3D microenvironment can yield significantly larger tumors in vivo than 2D-cultured cancer cells. Furthermore, the 3D vascularized tumors are 4.7 and 139.5 times more resistant to doxorubicin hydrochloride (a commonly used chemotherapy drug) than avascular microtumors and 2D-cultured cancer cells, respectively. Moreover, this high drug resistance of the 3D vascularized tumors can be overcome by using nanoparticle-mediated drug delivery. The high-fidelity 3D tumor model may be valuable for studying the effect of microenvironment on tumor progression, invasion, and metastasis and for developing effective therapeutic strategy to fight against cancer.

Therapeutic Potential of Matrix Metalloproteinase Inhibition in Breast Cancer

Matrix metalloproteinases (MMPs) are a family of zinc endopeptidases that cleave nearly all components of the extracellular matrix as well as many other soluble and cell-associated proteins. MMPs have been implicated in normal physiological processes, including development, and in the acquisition and progression of the malignant phenotype. Disappointing results from a series of clinical trials testing small molecule, broad spectrum MMP inhibitors as cancer therapeutics led to a re-evaluation of how MMPs function in the tumor microenvironment, and ongoing research continues to reveal that these proteins play complex roles in cancer development and progression. It is now clear that effective targeting of MMPs for therapeutic benefit will require selective inhibition of specific MMPs. Here, we provide an overview of the MMP family and its biological regulators, the tissue inhibitors of metalloproteinases (TIMPs). We then summarize recent research from model systems that elucidate how specific MMPs drive the malignant phenotype of breast cancer cells, including acquisition of cancer stem cell features and induction of the epithelial-mesenchymal transition, and we also outline clinical studies that implicate specific MMPs in breast cancer outcomes. We conclude by discussing ongoing strategies for development of inhibitors with therapeutic potential that are capable of selectively targeting the MMPs most responsible for tumor promotion, with special consideration of the potential of biologics including antibodies and engineered proteins based on the TIMP scaffold. J. Cell. Biochem. 118: 3531-3548, 2017. © 2017 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc.

Post-translational modification of the membrane type 1 matrix metalloproteinase (MT1-MMP) cytoplasmic tail impacts ovarian cancer multicellular aggregate dynamics

Membrane type 1 matrix metalloproteinase (MT1-MMP, MMP-14) is a transmembrane collagenase highly expressed in metastatic ovarian cancer and correlates with poor survival. Accumulating evidence shows that the cytoplasmic tail of MT1-MMP is subjected to phosphorylation, and this post-translational modification regulates enzymatic activity at the cell surface. To investigate the potential role of MT1-MMP cytoplasmic residue Thr⁵⁶⁷ phosphorylation in regulation of metastasis-associated behaviors, ovarian cancer cells that express low endogenous levels of MT1-MMP were engineered to express wild-type MT1-MMP, a phosphomimetic mutant (T567E), or a phosphodeficient mutant (T567A). Results show that Thr⁵⁶⁷ modulation influences behavior of both individual cells and multicellular aggregates (MCAs). The acquisition of either wild-type or mutant MT1-MMP expression results in altered cohesion of epithelial sheets and the formation of more compact MCAs relative to parental cells. Cells expressing MT1-MMP-T567E phosphomimetic mutants exhibit enhanced cell migration. Furthermore, MCAs formed from MT1-MMP-T567E-expressing cells adhere avidly to both intact ex vivo peritoneal explants and three-dimensional collagen gels. Interaction of these MCAs with peritoneal mesothelium disrupts mesothelial integrity, exposing the submesothelial collagen matrix on which MT1-MMP-T567E MCAs rapidly disperse. Together, these findings suggest that post-translational regulation of the Thr⁵⁶⁷ in the MT1-MMP cytoplasmic tail may function as a regulatory mechanism to impact ovarian cancer metastatic success.

Invadosomes are coming: new insights into function and disease relevance

Invadopodia and podosomes are discrete, actin-based molecular protrusions that form in cancer cells and normal cells, respectively, in response to diverse signaling pathways and extracellular matrix cues. Although they participate in a host of different cellular processes, they share a common functional theme of controlling pericellular proteolytic activity, which sets them apart from other structures that function in migration and adhesion, including focal adhesions, lamellipodia, and filopodia. In this review, we highlight research that explores the function of these complex structures, including roles for podosomes in embryonic and postnatal development, in angiogenesis and remodeling of the vasculature, in maturation of the postsynaptic membrane, in antigen sampling and recognition, and in cell-cell fusion mechanisms, as well as the involvement of invadopodia at multiple steps of the metastatic cascade, and how all of this may apply in the treatment of human disease states. Finally, we explore recent research that implicates a novel role for exosomes and microvesicles in invadopodia-dependent and invadopodia-independent mechanisms of invasion, respectively.