Localization of matrix metalloproteinase MMP-2 to the surface of invasive cells by interaction with integrin alpha v beta 3

Review of Integrin-Targeting Biomaterials in Tissue Engineering

The ability to direct cell behavior has been central to the success of numerous therapeutics to regenerate tissue or facilitate device integration. Biomaterial scientists are challenged to understand and modulate the interactions of biomaterials with biological systems in order to achieve effective tissue repair. One key area of research investigates the use of extracellular matrix-derived ligands to target specific integrin interactions and induce cellular responses, such as increased cell migration, proliferation, and differentiation of mesenchymal stem cells. These integrin-targeting proteins and peptides have been implemented in a variety of different polymeric scaffolds and devices to enhance tissue regeneration and integration. This review first presents an overview of integrin-mediated cellular processes that have been identified in angiogenesis, wound healing, and bone regeneration. Then, research utilizing biomaterials are highlighted with integrin-targeting motifs as a means to direct these cellular processes to enhance tissue regeneration. In addition to providing improved materials for tissue repair and device integration, these innovative biomaterials provide new tools to probe the complex processes of tissue remodeling in order to enhance the rational design of biomaterial scaffolds and guide tissue regeneration strategies.

Designing Enzyme-responsive Biomaterials

Enzymes are a class of protein that catalyze a wide range of chemical reactions, including the cleavage of specific peptide bonds. They are expressed in all cell types, play vital roles in tissue development and homeostasis, and in many diseases, such as cancer. Enzymatic activity is tightly controlled through the use of inactive pro-enzymes, endogenous inhibitors and spatial localization. Since the presence of specific enzymes is often correlated with biological processes, and these proteins can directly modify biomolecules, they are an ideal biological input for cell-responsive biomaterials. These materials include both natural and synthetic polymers, cross-linked hydrogels and self-assembled peptide nanostructures. Within these systems enzymatic activity has been used to induce biodegradation, release therapeutic agents and for disease diagnosis. As technological advancements increase our ability to quantify the expression and nanoscale organization of proteins in cells and tissues, as well as the synthesis of increasingly complex and well-defined biomaterials, enzyme-responsive biomaterials are poised to play vital roles in the future of biomedicine.

Targeting Tumor-Associated Macrophages by MMP2-Sensitive Apoptotic Body-Mimicking Nanoparticles

Tumor-associated macrophages (TAMs), a major player in the tumor microenvironment, were recently recognized as a potential therapeutic target. To date, very few anticancer drugs or drug-delivery systems were designed to target the TAMs. Inspired by the "eat me" signal, phosphatidylserine (PS), mediated phagocytic clearance of apoptotic bodies, in this study, the matrix metalloproteinase 2 (MMP2)-sensitive PS-modified nanoparticles were developed. In the design, the PS is externalized to the nanoparticles' surface only when the nanoparticles reach the MMP2-overexpressing tumor site, allowing for the TAM-specific phagocytosis. The nanoparticles' excellent macrophage/TAM selectivity was observed in various biological models, including various cell lines, coculture cells, coculture cell spheroids, zebrafish, and tumor-bearing mice. The nanoparticles' TAM specificity remarkably enhanced the TAM depletion capability of the loaded model drug, dasatinib, resulting in the improved anticancer activity. The MMP2-sensitive apoptotic body-mimicking nanoparticles might be a promising delivery tool for TAM-centered cancer diagnoses and treatments.

Interleukin 35 Delays Hindlimb Ischemia-Induced Angiogenesis Through Regulating ROS-Extracellular Matrix but Spares Later Regenerative Angiogenesis

Interleukin (IL) 35 is a novel immunosuppressive heterodimeric cytokine in IL-12 family. Whether and how IL-35 regulates ischemia-induced angiogenesis in peripheral artery diseases are unrevealed. To fill this important knowledge gap, we used loss-of-function, gain-of-function, omics data analysis, RNA-Seq, in vivo and in vitro experiments, and we have made the following significant findings: i) IL-35 and its receptor subunit IL-12RB2, but not IL-6ST, are induced in the muscle after hindlimb ischemia (HLI); ii) HLI-induced angiogenesis is improved in Il12rb2-/- mice, in ApoE-/-/Il12rb2-/- mice compared to WT and ApoE-/- controls, respectively, where hyperlipidemia inhibits angiogenesis in vivo and in vitro; iii) IL-35 cytokine injection as a gain-of-function approach delays blood perfusion recovery at day 14 after HLI; iv) IL-35 spares regenerative angiogenesis at the late phase of HLI recovery after day 14 of HLI; v) Transcriptome analysis of endothelial cells (ECs) at 14 days post-HLI reveals a disturbed extracellular matrix re-organization in IL-35-injected mice; vi) IL-35 downregulates three reactive oxygen species (ROS) promoters and upregulates one ROS attenuator, which may functionally mediate IL-35 upregulation of anti-angiogenic extracellular matrix proteins in ECs; and vii) IL-35 inhibits human microvascular EC migration and tube formation in vitro mainly through upregulating anti-angiogenic extracellular matrix-remodeling proteins. These findings provide a novel insight on the future therapeutic potential of IL-35 in suppressing ischemia/inflammation-triggered inflammatory angiogenesis at early phase but sparing regenerative angiogenesis at late phase.

Retooling Cancer Nanotherapeutics' Entry into Tumors to Alleviate Tumoral Hypoxia

Anti-hypoxia cancer nanomedicine (AHCN) holds exciting potential in improving oxygen-dependent therapeutic efficiencies of malignant tumors. However, most studies regarding AHCN focus on optimizing structure and function of nanomaterials with presupposed successful entry into tumor cells. From such a traditional perspective, the main barrier that AHCN needs to overcome is mainly the tumor cell membrane. However, such an oversimplified perspective would neglect that real tumors have many biological, physiological, physical, and chemical defenses preventing the current state-of-the-art AHCNs from even reaching the targeted tumor cells. Fortunately, in recent years, some studies are beginning to intentionally focus on overcoming physiological barriers to alleviate hypoxia. In this Review, the limitations behind the traditional AHCN delivery mindset are addressed and the key barriers that need to be surmounted before delivery to cancer cells and some good ways to improve cell membrane attachment, internalization, and intracellular retention are summarized. It is aimed to contribute to Review literature on this emerging topic through refreshing perspectives based on this work and what is also learnt from others. This Review would therefore assist AHCNs researchers to have a quick overview of the essential information and glean thought-provoking ideas to advance this sub-field in cancer nanomedicine.

Chitinase-3 like-protein-1 function and its role in diseases

Non-enzymatic chitinase-3 like-protein-1 (CHI3L1) belongs to glycoside hydrolase family 18. It binds to chitin, heparin, and hyaluronic acid, and is regulated by extracellular matrix changes, cytokines, growth factors, drugs, and stress. CHI3L1 is synthesized and secreted by a multitude of cells including macrophages, neutrophils, synoviocytes, chondrocytes, fibroblast-like cells, smooth muscle cells, and tumor cells. It plays a major role in tissue injury, inflammation, tissue repair, and remodeling responses. CHI3L1 has been strongly associated with diseases including asthma, arthritis, sepsis, diabetes, liver fibrosis, and coronary artery disease. Moreover, following its initial identification in the culture supernatant of the MG63 osteosarcoma cell line, CHI3L1 has been shown to be overexpressed in a wealth of both human cancers and animal tumor models. To date, interleukin-13 receptor subunit alpha-2, transmembrane protein 219, galectin-3, chemo-attractant receptor-homologous 2, and CD44 have been identified as CHI3L1 receptors. CHI3L1 signaling plays a critical role in cancer cell growth, proliferation, invasion, metastasis, angiogenesis, activation of tumor-associated macrophages, and Th2 polarization of CD4⁺ T cells. Interestingly, CHI3L1-based targeted therapy has been increasingly applied to the treatment of tumors including glioma and colon cancer as well as rheumatoid arthritis. This review summarizes the potential roles and mechanisms of CHI3L1 in oncogenesis and disease pathogenesis, then posits investigational strategies for targeted therapies.

A Complex and Evolutive Character: Two Face Aspects of ECM in Tumor Progression

Tumor microenvironment, including extracellular matrix (ECM) and stromal cells, is a key player during tumor development, from initiation, growth and progression to metastasis. During all of these steps, remodeling of matrix components occurs, changing its biochemical and physical properties. The global and basic cancer ECM model is that tumors are surrounded by activated stromal cells, that remodel physiological ECM to evolve into a stiffer and more crosslinked ECM than in normal conditions, thereby increasing invasive capacities of cancer cells. In this review, we show that this too simple model does not consider the complexity, specificity and heterogeneity of each organ and tumor. First, we describe the general ECM in context of cancer. Then, we go through five invasive and most frequent cancers from different origins (breast, liver, pancreas, colon, and skin), and show that each cancer has its own specific matrix, with different stromal cells, ECM components, biochemical properties and activated signaling pathways. Furthermore, in these five cancers, we describe the dual role of tumor ECM: as a protective barrier against tumor cell proliferation and invasion, and as a major player in tumor progression. Indeed, crosstalk between tumor and stromal cells induce changes in matrix organization by remodeling ECM through invadosome formation in order to degrade it, promoting tumor progression and cell invasion. To sum up, in this review, we highlight the specificities of matrix composition in five cancers and the necessity not to consider the ECM as one general and simple entity, but one complex, dynamic and specific entity for each cancer type and subtype.

Antimetastatic Potential of Rhodomyrtone on Human Chondrosarcoma SW1353 Cells

Chondrosarcoma is primary bone cancer, with the forceful capacity to cause local invasion and distant metastasis, and has a poor prognosis. Cancer metastasis is a complication of most cancers; it is one of the leading causes of cancer-related death. Rhodomyrtone is a pure compound that has been shown to induce apoptosis and antimetastasis in skin cancer. However, the inhibitory effect of rhodomyrtone on human chondrosarcoma cell metastasis is largely unknown. Effect of rhodomyrtone on cell viability in SW1353 cell was determined by MTT assay. Antimigration, anti-invasion, and antiadhesion were carried out to investigate the antimetastatic potential of rhodomyrtone on SW1353 cells. Gelatin zymography was performed to determine matrix metalloproteinase-2 (MMP-2) and MMP-9 activities. The effect of rhodomyrtone on the underlying mechanisms was performed by Western blot analysis. The results demonstrated that rhodomyrtone reduced cell viability of SW1353 cells at the low concentration (<3 μg/mL); cell viability was >80%. Rhodomyrtone at the subcytotoxic concentrations (0.5, 1.5, and 3 μg/mL) significantly inhibited cell migration, invasion, and adhesion of SW1353 cells in a dose-dependent fashion. Protein expression of integrin αv, integrin β3, and the downstream migratory proteins including focal adhesion kinase (FAK) and the phosphorylation of serine/threonine AKT, Ras, RhoA, Rac1, and Cdc42 were inhibited after treatment with rhodomyrtone. Moreover, we found that rhodomyrtone decreased the protein level of MMP-2 and MMP-9 as well as the enzyme activity in SW1353 cells. Meanwhile, tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2 expression was increased in a dose-dependent fashion. Besides, rhodomyrtone dramatically inhibited the expression of growth factor receptor-bound protein-2 (GRB2) and the phosphorylated form of extracellular signal regulation kinase1/2 (ERK1/2) and c-Jun N-terminal kinase1/2 (JNK1/2). These results indicated that rhodomyrtone inhibited SW1353 cell migration, invasion, and metastasis by suppressing integrin αvβ3/FAK/AKT/small Rho GTPases pathway as well as downregulation of MMP-2/9 via ERK and JNK signal inhibition. These findings indicate that rhodomyrtone possessed the antimetastasis activity that may be used for antimetastasis therapy in the future.

Invadopodia: clearing the way for cancer cell invasion

The invasive nature of many cancer cells involves the formation of F-actin-based, lipid-raft-enriched membrane protrusions known as invadopodia or, more broadly, invadosomes. Invadopodia are specialized adhesive structures arising from ventral cell surface within cell-extracellular matrix (ECM) contacts and concentrate high proteolytic activities that allow cells to overcome the dense scaffold of local microenvironment, comprising a natural barrier to cell spreading. This degradative activity distinguishes invadopodia from other adhesive structures like focal adhesions, lamellipodia or filopodia, and is believed to drive cancer progression.

BMP4 promotes the metastasis of gastric cancer by inducing epithelial-mesenchymal transition via ID1

Epithelial-mesenchymal transition (EMT) is a crucial process for cancer cells to acquire metastatic potential, which primarily causes death in gastric cancer (GC) patients. Bone morphogenetic protein 4 (BMP4) is a member of the TGF-β family that plays an indispensable role in human cancers. However, little is known about its roles in GC metastasis. In this study, BMP4 was found to be frequently overexpressed in GC tissues and was correlated with poor patient's prognosis. BMP4 was upregulated in GC cell lines and promoted EMT and metastasis of GC cells both in vitro and in vivo, whereas knockdown of BMP4 significantly inhibited EMT and metastasis of GC cells. Furthermore, the inhibitor of DNA binding 1 (also known as DNA-binding protein inhibitor ID1) was identified as a downstream target of BMP4 using PCR arrays and was upregulated via SMAD1/5/8 phosphorylation. ID1 knockdown attenuated BMP4-induced EMT and invasion in GC cells. Moreover, ID1 overexpression in BMP4 knockdown cells restored the promotion of EMT and cell invasion. In summary, BMP4 induced EMT and promoted GC metastasis by upregulating ID1 expression. Antagonizing BMP4 could be a potential therapeutic strategy for GC metastasis.

Small Ones to Fight a Big Problem-Intervention of Cancer Metastasis by Small Molecules

Metastasis represents the most lethal attribute of cancer and critically limits successful therapies in many tumor entities. The clinical need is defined by the fact that all cancer patients, who have or who will develop distant metastasis, will experience shorter survival. Thus, the ultimate goal in cancer therapy is the restriction of solid cancer metastasis by novel molecularly targeted small molecule based therapies. Biomarkers identifying cancer patients at high risk for metastasis and simultaneously acting as key drivers for metastasis are extremely desired. Clinical interventions targeting these key molecules will result in high efficiency in metastasis intervention. In result of this, personalized tailored interventions for restriction and prevention of cancer progression and metastasis will improve patient survival. This review defines crucial biological steps of the metastatic cascade, such as cell dissemination, migration and invasion as well as the action of metastasis suppressors. Targeting these biological steps with tailored therapeutic strategies of intervention or even prevention of metastasis using a wide range of small molecules will be discussed.

Advances in the Knowledge of the Molecular Biology of Glioblastoma and Its Impact in Patient Diagnosis, Stratification, and Treatment

Gliomas are the most common primary brain tumors in adults. They arise in the glial tissue and primarily occur in the brain. Low-grade tumors of World Health Organization (WHO) grade II tend to progress to high-grade gliomas of WHO grade III and, eventually, glioblastoma of WHO grade IV, which is the most common and deadly glioma, with a median survival of 12-15 months after final diagnosis. Knowledge of the molecular biology and genetics of glioblastoma has increased significantly in the past few years, giving rise to classification methods that can help in management and stratification of glioblastoma patients. However, glioblastoma remains an incurable disease. Glioblastoma cells have acquired genetic and metabolic adaptations in order to sustain tumor growth and progression, including changes in energetic metabolism, invasive capacity, migration, and angiogenesis, that make it very difficult to find suitable therapeutic targets and to develop effective drugs. The current standard of care for glioblastoma patients is surgery followed by radiotherapy plus concomitant and adjuvant chemotherapy with temozolomide. Although progress in glioblastoma therapies in recent years has been more limited than in other tumors, numerous drugs and targets are being proposed and many clinical trials are underway to develop effective subtype-specific treatments.

Functionally heterogeneous human satellite cells identified by single cell RNA sequencing

Although heterogeneity is recognized within the murine satellite cell pool, a comprehensive understanding of distinct subpopulations and their functional relevance in human satellite cells is lacking. We used a combination of single cell RNA sequencing and flow cytometry to identify, distinguish, and physically separate novel subpopulations of human PAX7+ satellite cells (Hu-MuSCs) from normal muscles. We found that, although relatively homogeneous compared to activated satellite cells and committed progenitors, the Hu-MuSC pool contains clusters of transcriptionally distinct cells with consistency across human individuals. New surface marker combinations were enriched in transcriptional subclusters, including a subpopulation of Hu-MuSCs marked by CXCR4/CD29/CD56/CAV1 (CAV1+). In vitro, CAV1+ Hu-MuSCs are morphologically distinct, and characterized by resistance to activation compared to CAV1- Hu-MuSCs. In vivo, CAV1+ Hu-MuSCs demonstrated increased engraftment after transplantation. Our findings provide a comprehensive transcriptional view of normal Hu-MuSCs and describe new heterogeneity, enabling separation of functionally distinct human satellite cell subpopulations.

Collagen-Immobilized Extracellular FRET Reporter for Visualizing Protease Activity Secreted by Living Cells

Despite the diverse roles of cell-secreted proteases in the extracellular matrix (ECM), classical methods to analyze protease activity have not been explored at the cell culture site. Here, we report a stable, matrix-sticky, and protease-sensitive extracellular reporter that comprises a collagen-binding protein and a Förster resonance energy transfer (FRET) coupler of an enhanced green fluorescent protein and a small dye molecule. The extracellular FRET reporter via split intein-mediated protein trans-splicing is able to adhere to collagen matrices, leading to fluorescence changes by matrix metalloproteinase-2 (MMP2) activity during living cell culture without impeding cell viability. When a proMMP2 mutant (Y581A) with altered protease secretion and activity was transfected into cancer cells, the reporter revealed a dramatic reduction in MMP2 activity in both two- and three-dimensional culture systems, compared with cells transfected with wild-type proMMP2. Our reporter is immediately amenable to monitor protease activity in diverse ECM-resident cells as well as to study protease-related extracellular signaling and tissue remodeling.

Infection and Inflammation Imaging: Beyond FDG

This review discusses nuclear imaging of inflammation using molecular probes beyond fluoro-d-glucose, is structured by cellular targets, and focuses on those tracers that have been successfully applied clinically.

Immobilized RGD concentration and proteolytic degradation synergistically enhance vascular sprouting within hydrogel scaffolds of varying modulus

Insufficient vascularization limits the volume and complexity of engineered tissue. The formation of new blood vessels (neovascularization) is regulated by a complex interplay of cellular interactions with biochemical and biophysical signals provided by the extracellular matrix (ECM) necessitating the development of biomaterial approaches that enable systematic modulation in matrix properties. To address this need poly(ethylene) glycol-based hydrogel scaffolds were engineered with a range of decoupled and combined variations in integrin-binding peptide (RGD) ligand concentration, elastic modulus and proteolytic degradation rate using free-radical polymerization chemistry. The modularity of this system enabled a full factorial experimental design to simultaneously investigate the individual and interaction effects of these matrix cues on vascular sprout formation in 3 D culture. Enhancements in scaffold proteolytic degradation rate promoted significant increases in vascular sprout length and junction number while increases in modulus significantly and negatively impacted vascular sprouting. We also observed that individual variations in immobilized RGD concentration did not significantly impact 3 D vascular sprouting. Our findings revealed a previously unidentified and optimized combination whereby increases in both immobilized RGD concentration and proteolytic degradation rate resulted in significant and synergistic enhancements in 3 D vascular spouting. The above-mentioned findings would have been challenging to uncover using one-factor-at-time experimental analyses.

Recent insights into natural product inhibitors of matrix metalloproteinases

Members of the matrix metalloproteinase (MMP) family have biological functions that are central to human health and disease, and MMP inhibitors have been investigated for the treatment of cardiovascular disease, cancer and neurodegenerative disorders. The outcomes of initial clinical trials with the first generation of MMP inhibitors proved disappointing. However, our growing understanding of the complexities of the MMP function in disease, and an increased understanding of MMP protein architecture and control of activity now provide new opportunities and avenues to develop MMP-focused therapies. Natural products that affect MMP activities have been of strong interest as templates for drug discovery, and for their use as chemical tools to help delineate the roles of MMPs that still remain to be defined. Herein, we highlight the most recent discoveries of structurally diverse natural product inhibitors to these proteases.

Phage display screening of therapeutic peptide for cancer targeting and therapy

Recently, phage display technology has been announced as the recipient of Nobel Prize in Chemistry 2018. Phage display technique allows high affinity target-binding peptides to be selected from a complex mixture pool of billions of displayed peptides on phage in a combinatorial library and could be further enriched through the biopanning process; proving to be a powerful technique in the screening of peptide with high affinity and selectivity. In this review, we will first discuss the modifications in phage display techniques used to isolate various cancer-specific ligands by in situ, in vitro, in vivo, and ex vivo screening methods. We will then discuss prominent examples of solid tumor targeting-peptides; namely peptide targeting tumor vasculature, tumor microenvironment (TME) and over-expressed receptors on cancer cells identified through phage display screening. We will also discuss the current challenges and future outlook for targeting peptide-based therapeutics in the clinics.

Integrin-Mediated TGFβ Activation Modulates the Tumour Microenvironment

TGFβ (transforming growth factor-beta) is a pleotropic cytokine with contrasting effects in cancer. In normal tissue and early tumours, TGFβ acts as a tumour suppressor, limiting proliferation and inducing apoptosis. However, these effects are eventually abrogated by the loss or inactivation of downstream signalling within the TGFβ pathway, and in established tumours, TGFβ then acts as a tumour promotor through multiple mechanisms including inducing epithelial-to-mesenchymal transition (EMT), promoting formation of cancer-associated fibroblasts (CAFs) and increasing angiogenesis. TGFβ is secrereted as a large latent complex and is embedded in the extracellular matrix or held on the surface of cells and must be activated before mediating its multiple functions. Thus, whilst TGFβ is abundant in the tumour microenvironment (TME), its functionality is regulated by local activation. The αv-integrins are major activators of latent-TGFβ. The potential benefits of manipulating the immune TME have been highlighted by the clinical success of immune-checkpoint inhibitors in a number of solid tumour types. TGFβ is a potent suppressor of T-cell-mediated immune surveillance and a key cause of resistance to checkpoint inhibitors. Therefore, as certain integrins locally activate TGFβ, they are likely to have a role in the immunosuppressive TME, although this remains to be confirmed. In this review, we discussed the role of TGFβ in cancer, the role of integrins in activating TGFβ in the TME, and the potential benefits of targeting integrins to augment immunotherapies.

Bioresponsive Protein Complex of aPD1 and aCD47 Antibodies for Enhanced Immunotherapy

Despite the promising efficacy of immune checkpoint blockade (ICB) in treating many types of cancers, the clinical benefits have often been restricted by the low objective response rates and systemic immune-related adverse events. Here, a bioresponsive ICB treatment is developed based on the reactive oxygen species (ROS)-sensitive protein complex for controlled sequential release of anti- "don't eat me" signal antibody (aCD47) and antiprogrammed cell death protein 1 (aPD1), by leveraging the abundant ROS in the tumor microenvironment (TME). These protein complexes can also act as scavengers of ROS in the TME to reverse the immunosuppressive responses, thereby enhancing antitumor efficacy in vivo. In a melanoma cancer model, the synergistic antitumor efficacy was achieved, which was accompanied by enhanced T cell immune responses together with reduced immunosuppressive responses.

Matrix metalloproteinase-2: Not (just) a "hero" of the past

The 72-kDa type IV collagenase or gelatinase A is the second member of the matrix metalloproteinase family, MMP-2. Since the discovery of its first two substrates within components of the extracellular matrix, denatured interstitial type I collagen and native type IV collagen, the roles and various levels of regulation of MMP-2 have been intensively studied, mainly in vitro. Its (over)expression in most if not all tumors was considered a hallmark of cancer aggressiveness and boosted investigations aiming at its inhibition. Unfortunately, the enthusiasm subsided like a soufflé after clinical trial failures, mostly because of insufficient knowledge of in vivo MMP-2 activities and detrimental side effects of broad-spectrum MMP inhibition. Nowadays, MMP-2 remains a major topic of interest in research, the second in the MMP family after MMP-9. This review presents a broad overview of the major features of this protease. This knowledge is crucial to identify diagnostic or therapeutic strategies focusing on MMP-2. In this sense, recent publications and clinical trials underline the potential value of measuring circulating or tissular MMP-2 levels as diagnostic or prognostic tools, or as a useful secondary outcome for therapies against other primary targets. Direct MMP-2 inhibition has benefited from substantial progress in the design of more specific inhibitors but their in vivo application remains challenging but certainly worth the efforts it receives.

Tyrosine 51 residue of the syndecan-2 extracellular domain is involved in the interaction with and activation of pro-matrix metalloproteinase-7

Although syndecan-2 is known to interact with the matrix metalloproteinase-7 (MMP-7), the details of their interaction were unknown. Our experiments with a series of syndecan-2 extracellular domain deletion mutants show that the interaction is mediated through an interaction of the extracellular domain of syndecan-2 (residues 41 to 60) with the α2 helix-loop-α3 helix in the pro-domain of MMP-7. NMR and molecular docking model show that Glu7 of the α1 helix, Glu32 of the α2 helix, and Gly48 and Ser52 of the α2 helix-loop-α3 helix of the MMP-7 pro-domain form the syndecan-2-binding pocket, which is occupied by the side chain of tyrosine residue 51 (Tyr51) of syndecan-2. Consistent with this notion, the expression of a syndecan-2 mutant in which Tyr51 was changed to Ala diminished the interaction between the syndecan-2 extracellular domain and the pro-domain of MMP-7. Furthermore, HT-29 colon adenocarcinoma cells expressing the interaction-defective mutant exhibited reductions in the cell-surface localization of MMP-7, the processing of pro-MMP-7 into active MMP-7, the MMP-7-mediated extracellular domain shedding of both syndecan-2 and E-cadherin, and syndecan-2-mediated anchorage-independent growth. Collectively, these data strongly suggest that Tyr51 of the syndecan-2 extracellular domain mediates its interaction with and activating processing of pro-MMP-7 and regulates MMP-7-dependent syndecan-2 functions.

Matrix-metalloproteinase expression and gelatinase activity in the avian retina and their influence on Müller glia proliferation

Gelatinases are a class of matrix metalloproteinases (MMPs) that degrade the extracellular matrix (ECM) to regulate intercellular signaling and cell migration. Gelatinase activity is tightly regulated via proteolytic activation and through the expression of tissue inhibitors of matrix metalloproteinases (TIMPs). Gelatinase activity has been implicated in retinal pathophysiology in different animal models and human disease. However, the role of gelatinases in retinal regeneration remains uncertain. In this study we investigated the dynamic changes in gelatinase activity in response to excitotoxic damage and how this enzymatic activity influenced the formation of Müller glia progenitor cells (MGPCs) in the avian retina. This study used hydrogels containing a gelatinase-degradable fluorescent peptide to measure gelatinase activity in vitro and dye quenched gelatin to localize enzymatic activity in situ. These data were corroborated by using single cell RNA sequencing (scRNA-seq). Gelatinase mRNA, specifically MMP2, was detected in oligodendrocytes and Non-Astrocytic Inner Retinal Glia (NIRG). Total retinal gelatinase activity was reduced following NMDA-treatment, and sustained inhibition of MMP2 prior to damage or growth factor treatment increased the formation of proliferating MGPCs and c-fos signaling. We observed that microglia, Müller glia (MG), and NIRG cells were involved in regulating changes in gelatinase activity through TIMP2 and TIMP3. Collectively, these findings implicate MMP2 in reprogramming of Muller glia into MGPCs.

The protease systems and their pathogenic role in juvenile idiopathic arthritis

Numerous proteases produced by synovial cells of arthritic joints, chondrocytes, macrophages and polymorphonuclear cells have been identified as responsible for the joint damage in rheumatoid arthritis. There are few scientific contributions aimed to identify similar mechanisms in the joints of patients with juvenile idiopathic arthritis. Recently, some mechanisms emerged, triggered by the TH17 and TH1/TH17 lymphocytes, which could shed new light on unexpected pathogenic pathways of joint damage in the JIA, mainly regarding the RANK-RANKL pathway. Other novelties are linked to the mechanisms of acidification of the synovial fluid, which create a microenvironment suitable for the extracellular activity of lysosomal enzymes. Some biological drugs currently used in the therapy of JIA can interfere with these mechanisms.

Integrins: Moonlighting Proteins in Invadosome Formation

Invadopodia are actin-rich protrusions developed by transformed cells in 2D/3D environments that are implicated in extracellular matrix (ECM) remodeling and degradation. These structures have an undoubted association with cancer invasion and metastasis because invadopodium formation in vivo is a key step for intra/extravasation of tumor cells. Invadopodia are closely related to other actin-rich structures known as podosomes, which are typical structures of normal cells necessary for different physiological processes during development and organogenesis. Invadopodia and podosomes are included in the general term 'invadosomes,' as they both appear as actin puncta on plasma membranes next to extracellular matrix metalloproteinases, although organization, regulation, and function are slightly different. Integrins are transmembrane proteins implicated in cell-cell and cell-matrix interactions and other important processes such as molecular signaling, mechano-transduction, and cell functions, e.g., adhesion, migration, or invasion. It is noteworthy that integrin expression is altered in many tumors, and other pathologies such as cardiovascular or immune dysfunctions. Over the last few years, growing evidence has suggested a role of integrins in the formation of invadopodia. However, their implication in invadopodia formation and adhesion to the ECM is still not well known. This review focuses on the role of integrins in invadopodium formation and provides a general overview of the involvement of these proteins in the mechanisms of metastasis, taking into account classic research through to the latest and most advanced work in the field.

Label-free cell sorting strategies via biophysical and biochemical gradients

Isolating active mesenchymal stem cells from a heterogeneous population is an essential step that determines the efficacy of stem cell therapy such as for osteoarthritis. Nowadays, the gold standard of cell sorting, fluorescence-activated cell sorting, relies on labelling surface markers via antibody-antigen reaction. However, sorting stem cells with high stemness usually requires the labelling of multiple biomarkers. Moreover, the labelling process is costly, and the high operating pressure is harmful to cell functionality and viability. Although label-free cell sorting, based on physical characteristics, has gained increasing interest in the past decades, it has not shown the ability to eliminate stem cells with low stemness. Cell motility, as a novel sorting marker, is hence proposed for label-free sorting active stem cells. Accumulating evidence has demonstrated the feasibility in manipulating directional cell migration through patterning the biophysical, biochemical or both gradients of the extracellular matrix. However, applying those findings to label-free cell sorting has not been well discussed and studied. This review thus first provides a brief overview about the effect of biophysical and biochemical gradients of the extracellular matrix on cell migration. State-of-the-art fabrication techniques for generating such gradients of hydrogels are then introduced. Among current research, the authors suggest that hydrogels with dual-gradients of biochemistry and biophysics are potential tools for accurate label-free cell sorting with satisfactory selectivity and efficiency.

TRANSLATIONAL POTENTIAL OF THIS ARTICLE

The reviewed label-free cell sorting approaches enable us to isolate active cell for cytotherapy. The proposed system can be further modified for single-cell analysis and drug screening.

Hic-5 regulates Src-induced invadopodia rosette formation and organization

Fibroblasts transformed by the proto-oncogene Src form individual invadopodia that can spontaneously self-organize into large matrix-degrading superstructures called rosettes. However, the mechanisms by which the invadopodia can spatiotemporally reorganize their architecture is not well understood. Here, we show that Hic-5, a close relative of the scaffold protein paxillin, is essential for the formation and organization of rosettes in active Src-transfected NIH3T3 fibroblasts and cancer-associated fibroblasts. Live cell imaging, combined with domain-mapping analysis of Hic-5, identified critical motifs as well as phosphorylation sites that are required for the formation and dynamics of rosettes. Using pharmacological inhibition and mutant expression, we show that FAK kinase activity, along with its proximity to and potential interaction with the LD2,3 motifs of Hic-5, is necessary for rosette formation. Invadopodia dynamics and their coalescence into rosettes were also dependent on Rac1, formin, and myosin II activity. Superresolution microscopy revealed the presence of formin FHOD1 and INF2-mediated unbranched radial F-actin fibers emanating from invadopodia and rosettes, which may facilitate rosette formation. Collectively, our data highlight a novel role for Hic-5 in orchestrating the organization of invadopodia into higher-order rosettes, which may promote the localized matrix degradation necessary for tumor cell invasion.

Magnetic Semiconductor Gd-Doping CuS Nanoparticles as Activatable Nanoprobes for Bimodal Imaging and Targeted Photothermal Therapy of Gastric Tumors

Targeted delivery of enzyme-activatable probes into cancer cells to facilitate accurate imaging and on-demand photothermal therapy (PTT) of cancers with high spatiotemporal precision promises to advance cancer diagnosis and therapy. Here, we report a tumor-targeted and matrix metalloprotease-2 (MMP-2)-activatable nanoprobe (T-MAN) formed by covalent modification of Gd-doping CuS micellar nanoparticles with cRGD and an MMP-2-cleavable fluorescent substrate. T-MAN displays a high r₁ relaxivity (∼60.0 mM^-1 s^-1 per Gd³⁺ at 1 T) and a large near-infrared (NIR) fluorescence turn-on ratio (∼185-fold) in response to MMP-2, allowing high-spatial-resolution magnetic resonance imaging (MRI) and low-background fluorescence imaging of gastric tumors as well as lymph node (LN) metastasis in living mice. Moreover, T-MAN has a high photothermal conversion efficiency (PCE, ∼70.1%) under 808 nm laser irradiation, endowing it with the ability to efficiently generate heat to kill tumor cells. We demonstrate that T-MAN can accumulate preferentially in gastric tumors (∼23.4% ID%/g at 12 h) after intravenous injection into mice, creating opportunities for fluorescence/MR bimodal imaging-guided PTT of subcutaneous and metastatic gastric tumors. For the first time, accurate detection and laser irradiation-initiated photothermal ablation of orthotopic gastric tumors in intraoperative mice was also achieved. This study highlights the versatility of using a combination of dual biomarker recognition (i.e., α_vβ₃ and MMP-2) and dual modality imaging (i.e., MRI and NIR fluorescence) to design tumor-targeting and activatable nanoprobes with improved selectivity for cancer theranostics in vivo.

Tumor gene therapy by systemic delivery of plasmid DNA with cell-penetrating peptides

Gene therapy is a prospective strategy for treating cancer. However, finding efficient and tumor-specific gene delivery vectors remains an issue. Tumor responsive cell-penetrating peptide (CPP) PepFect144 (PF144) has previously been shown to deliver reporter gene encoding plasmid DNA specifically into tumors upon systemic administration, but its capability to reduce tumor growth has not yet been evaluated. Here, we study the potential of PF144-based anti-angiogenic gene delivery to inhibit tumor growth by silencing vascular endothelial growth factor (VEGF) expression in tumors. This approach led to the inhibition of tumor growth in both the HT1080 fibrosarcoma model and orthotopic 4T1 breast tumor model. We additionally saw that the addition of αvβ3 integrin targeting did not further improve the tumor sensitive CPPs. Our results suggest that activatable cell-penetrating peptide PF144 is a promising nonviral plasmid DNA delivery vector for cancer treatment.

The potential for remodelling the tumour vasculature in glioblastoma

Despite significant improvements in the clinical management of glioblastoma, poor delivery of systemic therapies to the entire population of tumour cells remains one of the biggest challenges in the achievement of more effective treatments. On the one hand, the abnormal and dysfunctional tumour vascular network largely limits blood perfusion, resulting in an inhomogeneous delivery of drugs to the tumour. On the other hand, the presence of an intact blood-brain barrier (BBB) in certain regions of the tumour prevents chemotherapeutic drugs from permeating through the tumour vessels and reaching the diseased cells. In this review we analyse in detail the implications of the presence of a dysfunctional vascular network and the impenetrable BBB on drug transport. We discuss advantages and limitations of the currently available strategies for remodelling the tumour vasculature aiming to ameliorate the above mentioned limitations. Finally we review research methods for visualising vascular dysfunction and highlight the power of DCE- and DSC-MRI imaging to assess changes in blood perfusion and BBB permeability.

The HU177 Collagen Epitope Controls Melanoma Cell Migration and Experimental Metastasis by a CDK5/YAP-Dependent Mechanism

Stromal components not only help form the structure of neoplasms such as melanomas, but they also functionally contribute to their malignant phenotype. Thus, uncovering signaling pathways that integrate the behavior of both tumor and stromal cells may provide unique opportunities for the development of more effective strategies to control tumor progression. In this regard, extracellular matrix-mediated signaling plays a role in coordinating the behavior of both tumor and stromal cells. Here, evidence is provided that targeting a cryptic region of the extracellular matrix protein collagen (HU177 epitope) inhibits melanoma tumor growth and metastasis and reduces angiogenesis and the accumulation of α-SMA-expressing stromal cell in these tumors. The current study suggests that the ability of the HU177 epitope to control melanoma cell migration and metastasis depends on the transcriptional coactivator Yes-associated protein (YAP). Melanoma cell interactions with the HU177 epitope promoted nuclear accumulation of YAP by a cyclin-dependent kinase-5-associated mechanism. These findings provide new insights into the mechanism by which the anti-HU177 antibody inhibits metastasis, and uncovers an unknown signaling pathway by which the HU177 epitope selectively reprograms melanoma cells by regulating nuclear localization of YAP. This study helps to define a potential new therapeutic strategy to control melanoma tumor growth and metastasis that might be used alone or in combination with other therapeutics.

Self-Assembled Nanomedicines for Anticancer and Antibacterial Applications

Self-assembly strategies have been widely applied in the nanomedicine field, which provide a convenient approach for building various structures for delivery carriers. When cooperating with biomolecules, self-assembly systems have significant influence on the cell activity and life process and could be used for regulating nanodrug activity. In this review, self-assembled nanomedicines are introduced, including materials, encapsulation, and releasing strategies, where self-assembly strategies are involved. Furthermore, as a promising and emerging area for nanomedicine, in situ self-assembly of anticancer drugs and supramolecular antibiotic switches is also discussed about how to regulate drug activity. Selective pericellular assembly can block mass transformation of cancer cells inducing cell apoptosis, and the intracellular assembly can either cause cell death or effectively avoid drug elimination from cytosol of cancer cells because of the assembly-induced retention (AIR) effect. Host-guest interactions of drug and competitive molecules offer reversible regulations of antibiotic activity, which can reduce drug-resistance and inhibit the generation of drug-resistant bacteria. Finally, the challenges and development trend in the field are discussed.

ZKSCAN3 promotes breast cancer cell proliferation, migration and invasion

ZKSCAN3, a zinc-finger transcription factor, which has been shown to be upregulated in several human cancer. However, the expression level, function and mechanism of ZKSCAN3 in breast cancer remains unknown. In the current study, immunohistochemistry, western blot and quantitative real time polymerase chain reaction (qRT-PCR) results showed that ZKSCAN3 was overexpressed in breast cancer tissue compared with normal breast tissue. Through analyzing the clinicopathological characteristics, we demonstrated that positive ZKSCAN3 expression predicted poor prognosis of patients with breast cancer. The expression level of ZKSCAN3 protein/mRNA in breast cancer cells (MCF-7 and MDA-MB-231) was higher than its expression in normal breast cells (HBL-100). Knocking down ZKSCAN3 via its short hairpin RNA (shRNA) in MCF-7 and MDA-MB-231 inhibited cell viability, migration and invasion. Western blot analysis showed that ZKSCAN3 silencing lead to significant decreases in the expression of Cyclin D1, B-cell lymphoma-2 (Bcl-2), and matrix metalloproteinase (MMP)-2/MMP-9, as well as increases in the expression of Bcl2 Associated X Protein (Bax) in breast cancer cells. Additionally, ZKSCAN3-shRNA expression markedly suppressed tumor growth in breast cancer xenograft mice. Finally, we demonstrated that silencing of ZKSCAN3 was able to inhibit Akt/mTOR signaling pathway by blocking p-Akt and p-mTOR protein expression in breast cancer cells. These results demonstrate that ZKSCAN3 plays a significant role in the progression of breast cancer. Therefore, ZKSCAN3 is a potential therapeutic target for breast cancer.

Targeting the MMP-14/MMP-2/integrin αvβ3 axis with multispecific N-TIMP2-based antagonists for cancer therapy

The pathophysiological functions of the signaling molecules matrix metalloproteinase-14 (MMP-14) and integrin α_vβ₃ in various types of cancer are believed to derive from their collaborative activity in promoting invasion, metastasis, and angiogenesis, as shown in vitro and in vivo The two effectors act in concert in a cell-specific manner through the localization of pro-MMP-2 to the cell surface, where it is processed to intermediate and matured MMP-2. The matured MMP-2 product is localized to the cell surface via its binding to integrin α_vβ₃ The MMP-14/MMP-2/integrin α_vβ₃ axis thus constitutes an attractive putative target for therapeutic interventions, but the development of inhibitors that target this axis remains an unfulfilled task. To address the lack of such multitarget inhibitors, we have established a combinatorial approach that is based on flow cytometry screening of a yeast-displayed N-TIMP2 (N-terminal domain variant of tissue inhibitor of metalloproteinase-2) mutant library. On the basis of this screening, we generated protein monomers and a heterodimer that contain monovalent and bivalent binding epitopes to MMP-14 and integrin α_vβ₃ Among these proteins, the bi-specific heterodimer, which bound strongly to both MMP-14 and integrin α_vβ₃, exhibited superior ability to inhibit MMP-2 activation and displayed the highest inhibitory activity in cell-based models of a MMP-14-, MMP-2-, and integrin α_vβ₃-dependent glioblastoma and of endothelial cell invasiveness and endothelial capillary tube formation. These assays enabled us to show the superiority of the combined target effects of the inhibitors and to investigate separately the role each of the three signaling molecules in various malignant processes.

Adhesion in Physiological, Benign and Malignant Proliferative States of the Endometrium: Microenvironment and the Clinical Big Picture

Although the developments in cellular and molecular biology over the last few decades have significantly advanced our understanding of the processes and players that regulate invasive disease, many areas of uncertainty remain. This review will discuss the contribution of dysregulated cell⁻cell and cell⁻matrix adhesion to the invasion in both benign and malignant contexts. Using the endometrium as an illustrative tissue that undergoes clinically significant invasion in both contexts, the adhesion considerations in the cells ("seed") and their microenvironment ("soil") will be discussed. We hope to orientate this discussion towards translational relevance for the diagnosis and treatment of endometrial conditions, which are currently associated with significant morbidity and mortality.

Anti-apoptotic activity of human matrix metalloproteinase-2 attenuates diabetes mellitus

BACKGROUND

Chronic progression of diabetes is associated with decreased pancreatic islet mass due to apoptosis of β-cells. Patients with diabetes have increased circulating matrix metalloproteinase-2 (MMP2); however, the physiological significance has remained elusive. This study tested the hypothesis that MMP2 inhibits cell apoptosis, including islet β-cells.

METHODS

Samples from diabetic patients and newly developed transgenic mice overexpressing human MMP2 (hMMP2) were harnessed, and diabetes was induced with streptozotocin.

RESULTS

Circulating hMMP2 was significantly increased in diabetic patients compared to controls and significantly correlated with the serum C-peptide levels. The diabetic hMMP2 transgenic mice showed significant improvements in glycemia, glucose tolerance and insulin secretion compared to diabetic wild type mice. Importantly, the increased hMMP2 levels in mice correlated with significant reduction in islet β-cell apoptosis compared to wild-type counterparts, and an inhibitor of hMMP2 reversed this mitigating activity against diabetes. The increased activation of Akt and BAD induced by hMMP2 in β-cells compared to controls, links this signaling pathway to the anti-apoptotic activity of hMMP2, a property that was reversible by both an hMMP2 inhibitor and antibody against integrin-β3.

CONCLUSION

Overall, this study demonstrates that increased expression of hMMP2 may attenuate the severity of diabetes by protecting islet β-cells from apoptosis through an integrin-mediated activation of the Akt/BAD pathway.

Cancer Invasion: Watch Your Neighbourhood!

The critical event in neoplastic diseases is the invasion of surrounding tissue by cancer cells. This event greatly reduces treatment options, and makes cancer a lethal disease. Factors that initiate cancer invasion are not well understood, neither do we have mechanistic insights in the process itself. Recently, a new concept has emerged: the tissue surrounding tumor cells, ie, the tumor microenvironment, may play an important, if not decisive role in triggering invasion. This concept is based on data from many laboratories working on the cell biology of cancer invasion. In this review, we survey several components of the tumor microenvironment, including extracellular matrix macromolecules, metalloproteinases and soluble factors, and discuss their potential involvement in stimulating cancer cell motility. These novel views may have far-reaching consequences, since “normal” tissue microenvironment components, rather than the traditional tumor cells themselves, may eventually become targets for devising new treatments that prevent, inhibit or block cancer invasion and metastasis.

MDA-MB-231 and 8701BC breast cancer lines promote the migration and invasiveness of ECV304 cells on 2D and 3D type-I collagen matrix

Tumor angiogenesis is a multiphasic process, having the extracellular matrix remodeling as critical step. Different classes of proteolytic enzymes in matrix digestion/remodeling are involved. The role of lytic enzymes and their activation mode have not been completely elucidated. Herein, the crosstalk between endothelia and tumor cells, by realization of bi- and three-dimensional endothelial and breast cancer cells co-cultures, were studied in vitro. Particularly, the effects of two tumor conditioned media (TCM) were assessed about endothelial proliferation, migration, and invasiveness. An increase in expression of pro-MMP9 was detected when endothelial cells were cultured in the presence of both TCM; such as an up-regulation of MMP1 and MMP14 and a down-regulation of MMP7. Moreover the increased MMP2 gene expression from one of them and the stimulation MMP3 synthesis from the other one were observed; an increases of β3-integrin, VEGFA, and DPP4 molecules were detected when endothelia cells are cultured with both TCM. The selection/characterization of elements present in conditioned media from breast cancer cells differently affect endothelial cells, make them potential effectors useful in breast cancer treatment.

The kallikrein-Kinin system modulates the progression of colorectal liver metastases in a mouse model

Background

The Kallikrein-Kinin System (KKS) has been found to play a role in tumor progression in several cancers. The KKS metabolic cascade depends on signalling through two cross talking receptors; bradykinin receptor 1 (B1R) and bradykinin receptor 2 (B2R). Activation of the Kinin receptor is responsible for multiple pathophysiologic functions including increase of vascular permeability and induction of host inflammatory responses that exert diverse effects on tumor growth.

Methods

B1R and B2R expression on mouse and human CRC cell lines was investigated. Changes in tumor growth and progression was assessed in male CBA mice bearing colorectal liver metastases (CRLM) following treatment with B1R or B2R blockers. In vitro cultures of human SW-480 and mouse colorectal cancer (MoCR) cell lines were examined for changes in their proliferation and migration properties following treatment with B1R or B2R blockers.

Results

Both colorectal cancer cell lines tested strongly positive for B1R and B2R expression. Inhibition of both receptors retarded tumor growth but only B1R blockade significantly reduced tumor load and increased tumor apoptosis. Blockade of either receptor reduced tumor vascularization in vivo and significantly inhibited proliferation and migration of colorectal cancer cells in vitro.

Conclusion

Taken together, the present study demonstrated that kinin receptor blockade inhibited tumor growth and reduced its invading properties suggesting that KKS manipulation could be a novel target in colorectal cancer therapy.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4260-6) contains supplementary material, which is available to authorized users.

Cancer Cell Mechanics: Adhesion G Protein-coupled Receptors in Action?

In mammals, numerous organ systems are equipped with adhesion G protein-coupled receptors (aGPCRs) to shape cellular processes including migration, adhesion, polarity and guidance. All of these cell biological aspects are closely associated with tumor cell biology. Consistently, aberrant expression or malfunction of aGPCRs has been associated with dysplasia and tumorigenesis. Mounting evidence indicates that cancer cells comprise viscoelastic properties that are different from that of their non-tumorigenic counterparts, a feature that is believed to contribute to the increased motility and invasiveness of metastatic cancer cells. This is particularly interesting in light of the recent identification of the mechanosensitive facility of aGPCRs. aGPCRs are signified by large extracellular domains (ECDs) with adhesive properties, which promote the engagement with insoluble ligands. This configuration may enable reliable force transmission to the ECDs and may constitute a molecular switch, vital for mechano-dependent aGPCR signaling. The investigation of aGPCR function in mechanosensation is still in its infancy and has been largely restricted to physiological contexts. It remains to be elucidated if and how aGPCR function affects the mechanoregulation of tumor cells, how this may shape the mechanical signature and ultimately determines the pathological features of a cancer cell. This article aims to view known aGPCR functions from a biomechanical perspective and to delineate how this might impinge on the mechanobiology of cancer cells.