High threshold of β1 integrin inhibition required to block collagen I-induced membrane type-1 matrix metalloproteinase (MT1-MMP) activation of matrix metalloproteinase 2 (MMP-2)

l-carvone decreases breast cancer cells adhesion, migration, and invasion by suppressing FAK activation

Breast cancer is one of the most common types of cancer in the world and current therapeutic strategies present severe drawbacks. l-carvone (CRV), a monoterpene found in Mentha spicata (spearmint), has been reported to have potent anti-inflammatory activity. Here, we examined the role of CRV in breast cancer cell adhesion, migration and invasion in vitro and how this component could suppress the growth of Ehrlich carcinoma-bearing mice. In vivo, treatment with CRV significantly decreased tumor growth, increased tumor necrosis area, and reduced the expression of VEGF and HIF-1α in Ehrlich carcinoma-bearing mice. Furthermore, the anticancer efficacy of CRV was similar to currently used chemotherapy (Methotrexate), and the combination of CRV with MTX potentiated the chemotherapy effects. Further mechanistic investigation in vitro revealed that CRV modulates the interaction of breast cancer cells with the extracellular matrix (ECM) by disrupting focal adhesion, which was shown by scanning electron microscopy (SEM) and immunofluorescence. Moreover, CRV caused a decrease in β₁-integrin expression and inhibited focal adhesion kinase (FAK) activation. FAK is one of the most important downstream activators of several metastatic processes, including MMP-2 mediated invasion and HIF-1α/VEGF angiogenesis stimulus, both of which were found to be reduced in MDA-MB-231 cells exposed to CRV. Our results provide new insight about targeting β₁-integrin/FAK signaling pathway with CRV, which could be a new potential agent in the treatment of breast cancer.

Integrin β1 in Pancreatic Cancer: Expressions, Functions, and Clinical Implications

Simple Summary

Pancreatic cancer (PC) is a highly aggressive malignant tumor with an extremely poor prognosis. Early diagnosis and treatment are key to improving the survival rate of PC patients. Emerging studies show that integrins might contribute to the pathogenesis of PC. This review presents the various signaling pathways that are mediated by integrins in PC and emphasizes the multiple functions of integrin β1 in malignant behaviors of PC. It also discusses the clinical significance of integrin β1 as well as integrin β1-based therapy in PC patients.

Abstract

Pancreatic cancer (PC) is characterized by rapid progression and a high mortality rate. The current treatment is still based on surgical treatment, supplemented by radiotherapy and chemotherapy, and new methods of combining immune and molecular biological treatments are being explored. Despite this, the survival rate of PC patients is still very disappointing. Therefore, clarifying the molecular mechanism of PC pathogenesis and developing precisely targeted drugs are key to improving PC prognosis. As the most common β subunit of the integrin family, integrin β1 has been proved to be closely related to the vascular invasion, distant metastasis, and survival of PC patients, and treatment targeting integrin β1 in PC has gained initial success in animal models. In this review, we summarize the various signaling pathways by which integrins are involved in PC, focusing on the roles of integrin β1 in the malignant behaviors of PC. Additionally, recent studies regarding the feasibility of integrin β1 as a diagnostic and prognostic biomarker in PC are also discussed. Finally, we present the progress of several integrin β1-based clinical trials to highlight the potential of integrin β1 as a target for personalized therapy in PC.

Matrix Metalloproteinases Shape the Tumor Microenvironment in Cancer Progression

Cancer progression with uncontrolled tumor growth, local invasion, and metastasis depends largely on the proteolytic activity of numerous matrix metalloproteinases (MMPs), which affect tissue integrity, immune cell recruitment, and tissue turnover by degrading extracellular matrix (ECM) components and by releasing matrikines, cell surface-bound cytokines, growth factors, or their receptors. Among the MMPs, MMP-14 is the driving force behind extracellular matrix and tissue destruction during cancer invasion and metastasis. MMP-14 also influences both intercellular as well as cell-matrix communication by regulating the activity of many plasma membrane-anchored and extracellular proteins. Cancer cells and other cells of the tumor stroma, embedded in a common extracellular matrix, interact with their matrix by means of various adhesive structures, of which particularly invadopodia are capable to remodel the matrix through spatially and temporally finely tuned proteolysis. As a deeper understanding of the underlying functional mechanisms is beneficial for the development of new prognostic and predictive markers and for targeted therapies, this review examined the current knowledge of the interplay of the various MMPs in the cancer context on the protein, subcellular, and cellular level with a focus on MMP14.

Exposure to Bacteriophages T4 and M13 Increases Integrin Gene Expression and Impairs Migration of Human PC-3 Prostate Cancer Cells

The interaction between bacteriophages and integrins has been reported in different cancer cell lines, and efforts have been undertaken to understand these interactions in tumor cells along with their possible role in gene alterations, with the aim to develop new cancer therapies. Here, we report that the non-specific interaction of T4 and M13 bacteriophages with human PC-3 cells results in differential migration and varied expression of different integrins. PC-3 tumor cells (at 70% confluence) were exposed to 1 × 10⁷ pfu/mL of either lytic T4 bacteriophage or filamentous M13 bacteriophage. After 24 h of exposure, cells were processed for a histochemical analysis, wound-healing migration assay, and gene expression profile using quantitative real-time PCR (qPCR). qPCR was performed to analyze the expression profiles of integrins ITGAV, ITGA5, ITGB1, ITGB3, and ITGB5. Our findings revealed that PC-3 cells interacted with T4 and M13 bacteriophages, with significant upregulation of ITGAV, ITGA5, ITGB3, ITGB5 genes after phage exposure. PC-3 cells also exhibited reduced migration activity when exposed to either T4 or M13 phages. These results suggest that wildtype bacteriophages interact non-specifically with PC-3 cells, thereby modulating the expression of integrin genes and affecting cell migration. Therefore, bacteriophages have future potential applications in anticancer therapies.

Cell and extracellular matrix interaction models in benign mesothelial and malignant pleural mesothelioma cells in 2D and 3D in-vitro

Malignant pleural mesothelioma (MPM) is an aggressive tumour that grows in the pleural cavity. MPM spheroids released in the pleural fluid can form new tumour foci. Cell-cell, cell-extracellular matrix (ECM) interactions in 2D and 3D impact malignant cell behaviour during cell adhesion, migration, proliferation and epithelial-mesenchymal transition (EMT). In this study, epithelioid, biphasic and sarcomatoid MPM cell types as well as benign mesothelial cells were tested with regards to the above phenotypes. Fibronectin (FN) and homologous cell-derived extracellular matrix (hcd-ECM) treated substratum differentially affected the above phenotypes. 3D MPM spheroid invasion was higher in FN-collagen matrices in the epithelioid and biphasic cells, while 3D cell cultures of epithelioid and sarcomatoid MPM cells in FN-collagen showed a higher contractility compared to hcd-ECM-collagen. Cell aggregates demonstrated invasive behaviour in hcd-ECM matrices alone. Our results suggest that ECM and the dimensionality affect malignant cell behaviour during cell culture studies.

Hold on or Cut? Integrin- and MMP-Mediated Cell-Matrix Interactions in the Tumor Microenvironment

The tumor microenvironment (TME) has become the focus of interest in cancer research and treatment. It includes the extracellular matrix (ECM) and ECM-modifying enzymes that are secreted by cancer and neighboring cells. The ECM serves both to anchor the tumor cells embedded in it and as a means of communication between the various cellular and non-cellular components of the TME. The cells of the TME modify their surrounding cancer-characteristic ECM. This in turn provides feedback to them via cellular receptors, thereby regulating, together with cytokines and exosomes, differentiation processes as well as tumor progression and spread. Matrix remodeling is accomplished by altering the repertoire of ECM components and by biophysical changes in stiffness and tension caused by ECM-crosslinking and ECM-degrading enzymes, in particular matrix metalloproteinases (MMPs). These can degrade ECM barriers or, by partial proteolysis, release soluble ECM fragments called matrikines, which influence cells inside and outside the TME. This review examines the changes in the ECM of the TME and the interaction between cells and the ECM, with a particular focus on MMPs.

Cancer cells grown in 3D under fluid flow exhibit an aggressive phenotype and reduced responsiveness to the anti-cancer treatment doxorubicin

3D laboratory models of cancer are designed to recapitulate the biochemical and biophysical characteristics of the tumour microenvironment and aim to enable studies of cancer, and new therapeutic modalities, in a physiologically-relevant manner. We have developed an in vitro 3D model comprising a central high-density mass of breast cancer cells surrounded by collagen type-1 and we incorporated fluid flow and pressure. We noted significant changes in cancer cell behaviour using this system. MDA-MB231 and SKBR3 breast cancer cells grown in 3D downregulated the proliferative marker Ki67 (P < 0.05) and exhibited decreased response to the chemotherapeutic agent doxorubicin (DOX) (P < 0.01). Mesenchymal markers snail and MMP14 were upregulated in cancer cells maintained in 3D (P < 0.001), cadherin-11 was downregulated (P < 0.001) and HER2 increased (P < 0.05). Cells maintained in 3D under fluid flow exhibited a further reduction in response to DOX (P < 0.05); HER2 and Ki67 levels were also attenuated. Fluid flow and pressure was associated with reduced cell viability and decreased expression levels of vimentin. In summary, aggressive cancer cell behaviour and reduced drug responsiveness was observed when breast cancer cells were maintained in 3D under fluid flow and pressure. These observations are relevant for future developments of 3D in vitro cancer models and organ-on-a-chip initiatives.

Tumor-Cell-Surface Adherable Peptide-Drug Conjugate Prodrug Nanoparticles Inhibit Tumor Metastasis and Augment Treatment Efficacy

Cancer metastasis is the main cause of chemotherapeutic failure. Inhibiting the activity of matrix metalloproteinases (MMPs) is a common strategy for reducing metastasis. However, broad-spectrum MMP-inhibitors (MMPI) may cause undesired side effects. Here, we screened a selective MMP2 inhibitor (CCKIGLFRWR) and linked it with doxorubicin (DOX) to produce an amphiphilic peptide-drug conjugate (PDC). Then novel core-shell nanoparticles were self-assembled from PDC core and modified polylysine (MPL) shell. When the particles were passively targeted to the tumor site, the PDC core was exposed for charge switch of the MPL shell, aggregated for its transformation behavior, and specially adhered to the cell membrane. The disulfide bond between the MMPI peptide and DOX was broken via a low concentration of glutathione-mediated reduction in tumor microenvironment. DOX could effectively enter the tumor cells. Meanwhile, the MMPI peptide could selectively inhibit the activity of the MMP2 and effectively inhibit tumor metastasis.

The role of collagen in cancer: from bench to bedside

Collagen is the major component of the tumor microenvironment and participates in cancer fibrosis. Collagen biosynthesis can be regulated by cancer cells through mutated genes, transcription factors, signaling pathways and receptors; furthermore, collagen can influence tumor cell behavior through integrins, discoidin domain receptors, tyrosine kinase receptors, and some signaling pathways. Exosomes and microRNAs are closely associated with collagen in cancer. Hypoxia, which is common in collagen-rich conditions, intensifies cancer progression, and other substances in the extracellular matrix, such as fibronectin, hyaluronic acid, laminin, and matrix metalloproteinases, interact with collagen to influence cancer cell activity. Macrophages, lymphocytes, and fibroblasts play a role with collagen in cancer immunity and progression. Microscopic changes in collagen content within cancer cells and matrix cells and in other molecules ultimately contribute to the mutual feedback loop that influences prognosis, recurrence, and resistance in cancer. Nanoparticles, nanoplatforms, and nanoenzymes exhibit the expected gratifying properties. The pathophysiological functions of collagen in diverse cancers illustrate the dual roles of collagen and provide promising therapeutic options that can be readily translated from bench to bedside. The emerging understanding of the structural properties and functions of collagen in cancer will guide the development of new strategies for anticancer therapy.

Establishment of a Model of Microencapsulated SGC7901 Human Gastric Carcinoma Cells Cocultured with Tumor-Associated Macrophages

The important factors of poor survival of gastric cancer (GC) are relapse and metastasis. For further elucidation of the mechanism, a culture system mimicking the microenvironment of the tumor in humans was needed. We established a model of microencapsulated SGC7901 human GC cells and evaluated the effects of coculturing spheres with tumor-associated macrophages (TAMs). SGC7901 cells were encapsulated in alginate-polylysine-sodium alginate (APA) microcapsules using an electrostatic droplet generator. MTT assays showed that the numbers of microencapsulated cells were the highest after culturing for 14 days. Metabolic curves showed consumption of glucose and production of lactic acid by day 20. Immunocytochemistry confirmed that Proliferating Cell Nuclear Antigen (PCNA) and Vascular Endothelial Growth Factor (VEGF) were expressed in microencapsulated SGC7901 cells on days 7 and 14. The expression of PCNA was observed outside spheroids; however, VEGF was found in the entire spheroids. PCNA and VEGF were increased after being cocultured with TAMs. Matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) expressions were detected in the supernatant of microencapsulated cells cocultured with TAMs but not in microencapsulated cells. Our study confirms the successful establishment of the microencapsulated GC cells. TAMs can promote PCNA, VEGF, MMP-2, and MMP-9 expressions of the GC cells.

β1 Integrins as Therapeutic Targets to Disrupt Hallmarks of Cancer

Integrins belong to a large family of αβ heterodimeric transmembrane proteins first recognized as adhesion molecules that bind to dedicated elements of the extracellular matrix and also to other surrounding cells. As important sensors of the cell microenvironment, they regulate numerous signaling pathways in response to structural variations of the extracellular matrix. Biochemical and biomechanical cues provided by this matrix and transmitted to cells via integrins are critically modified in tumoral settings. Integrins repertoire are subjected to expression level modifications, in tumor cells, and in surrounding cancer-associated cells, implicated in tumor initiation and progression as well. As critical players in numerous cancer hallmarks, defined by Hanahan and Weinberg (2011), integrins represent pertinent therapeutic targets. We will briefly summarize here our current knowledge about integrin implications in those different hallmarks focusing primarily on β1 integrins.

Toll-like receptor 2 (TLR2) induces migration and invasive mechanisms in rheumatoid arthritis

Introduction

This study investigates the role of Toll-like receptor 2 (TLR2) in the regulation of migratory and invasive mechanisms in rheumatoid arthritis (RA).

Methods

Invasion, migration, matrix metalloproteinase (MMP)-1, -3 and tissue inhibitor of matrix metalloproteinase-3 (TIMP-3) expression, β-integrin binding, cytoskeletal rearrangement and Ras-related C3 botulinum toxin substrate 1 (Rac1) activation in response to a TLR2-ligand, Pam3CSK4 (1 μg/ml), in ex vivo RA synovial tissue explants, primary RA synovial fibroblasts (RASFC) and microvascular endothelial cells (HMVEC) were assessed by Transwell Matrigel™ invasion chambers, enzyme-linked immunosorbent assay (ELISA), multiplex adhesion binding assay, reverse transcription polymerase chain reaction (RT-PCR), F-actin immunofluorescent staining, matrigel synovial outgrowths, Rac1 pull-down assays/Western blot and zymography. β1-integrin expression in RA/control synovial tissue was assessed by immunohistology. The effect of Pam3CSK4 on cell migration, invasion, MMP-3 and Rac1 activation was examined in the presence or absence of anti-β1-integrin (10 μg/ml) or anti-IgG control (10 μg/ml). The effect of an anti-TLR-2 mAb (OPN301)(1 μg/ml) or immunoglobulin G (IgG) control (1 μg/ml) on RASFC migration and RA synovial tissue MMP activity was assessed by wound assays, ELISA and zymography.

Results

Pam3CSK4 significantly induced cell migration, invasion, MMP-1, MMP-3, MMP-2 and MMP-9 expression and induced the MMP-1/TIMP-3 and MMP-3/TIMP-3 ratio in RASFC and explants (p <0.05). β1-integrin expression was significantly higher in RA synovial tissue compared to controls (p <0.05). Pam3CSK4 specifically induced β1-integrin binding in RASFC (p <0.05), with no effect observed for β2-4, β6, αvβ5 or α5β1. Pam3CSK4 increased β1-integrin mRNA expression, Rac1 activation, RASFC outgrowths and altered cytoskeletal dynamic through induction of filopodia formation. Pam3CSK4-regulated cell migration and invasion processes, but not MMP-3, were inhibited in the presence of anti-β1-integrin (p <0.05), with no effect observed for anti-IgG control. Furthermore, anti-β1-integrin inhibited Pam3CSK4-induced Rac1 activation. Finally, blockade of TLR2 with OPN301 significantly decreased spontaneous release of MMP-3, MMP-2 and MMP-9 and increased TIMP-3 secretion from RA synovial explant cultures (p <0.05). Incubation of RASFC with OPN301 RA ex vivo conditioned media inhibited migration and invasion compared to IgG control.

Conclusions

TLR2 activation induces migrational and invasive mechanisms, which are critically involved in the pathogenesis of RA, suggesting TLR2 as a potential therapeutic target for the treatment of RA.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0664-8) contains supplementary material, which is available to authorized users.