Metalloproteinases and their inhibitors in tumor angiogenesis

Recombinant human endostatin as a potential anti-angiogenic agent: therapeutic perspective and current status

Angiogenesis is the physiological process that results in the formation of new blood vessels develop from pre-existing vasculature and plays a significant role in several physiological and pathological processes. Inhibiting angiogenesis, a crucial mechanism in the growth and metastasis of cancer, has been proposed as a potential anticancer therapy. Different studies showed the beneficial effects of angiogenesis inhibitors either in patients suffering from different cancers, alone or in combination with conventional therapies. Even though there are currently a number of efficient anti-angiogenic drugs, including monoclonal antibodies and kinase inhibitors, the associated toxicity profile and their affordability constraints are prompting researchers to search for a safe and affordable angiostatic agent for cancer treatment. Endostatin is one of the endogenous anti-angiogenic candidates that have been extensively pursued for the treatment of cancer, but even over three decades after its discovery, we have not made much advancement in employing it as an anticancer therapeutic despite of its remarkable anti-angiogenic effect with low toxicity profile. A recombinant human endostatin (rh-Es) variant for non-small cell lung cancer was approved by China in 2006 and has since been used effectively. Several other successful clinical trials related to endostatin for various malignancies are either ongoing or have already been completed with promising results. Thus, in this review, we have provided an overview of existing anti-angiogenic drugs developed for cancer therapy, with a summary of tumour angiogenesis in the context of Endostatin, and clinical status of rh-Es in cancer treatment. Furthermore, we briefly discuss the various strategies to improve endostatin features (poor pharmacokinetic properties) for developing rh-Es as a safe and effective agent for cancer treatment.

Inhibition of tumor-specific angiogenesis by AS1411 aptamer functionalized Withaferin A loaded PEGylated nanoliposomes by targeting nucleolin

Angiogenesis is a vital process for tumor growth and metastasis. Inhibition of angiogenesis is a promising strategy in cancer treatment. In this study, we analyzed the anti-angiogenic activity of AS1411 functionalized Withaferin A encapsulated PEGylated nanoliposomes (ALW) using both in vitro and in vivo models. AS1411 aptamer functionalized nanoliposomes are an efficient drug delivery system for carrying chemotherapeutic agents to target cancer cells, and Withaferin A (WA) is a steroidal lactone known for potent anti-angiogenic activity. ALW showed significant inhibition in the migration and tube formation of endothelial cells, which are critical events in angiogenesis. In vivo angiogenesis study using ALW showed remarkable inhibition of tumor-directed capillary formation by altered serum cytokines, VEGF, GM-CSF, and NO levels. ALW treatment downregulated the gene expression of Matrix metalloproteinase (MMP)-2, MMP-9, VEGF, NF-kB and upregulated the expression of tissue inhibitor of metalloproteinase (TIMP)-1. Our results demonstrate that ALW inhibits tumor-specific angiogenesis by gene expression of NF-κB, VEGF, MMP-2, and MMP-9. The present study shows that using ALW can offer an attractive strategy for inhibiting tumor angiogenesis.

High levels of TIMP1 are associated with increased extracellular matrix stiffness in isocitrate dehydrogenase 1-wild type gliomas

Glioma progression is accompanied with increased tumor tissue stiffness, yet the underlying mechanisms are unclear. Herein, we employed atomic force microscopy analysis to show that tissue stiffness was higher in isocitrate dehydrogenase (IDH)-wild type gliomas than IDH-mutant gliomas. Bioinformatic analyses revealed that tissue inhibitor of metalloproteinase-1 (TIMP1) was one of the preferentially upregulated genes in IDH-wild type gliomas as compared to IDH-mutant gliomas, and its higher expression indicated worse prognosis of glioma patients. TIMP1 intensity determined by immunofluorescence staining on glioma tissues positively correlated with glioma tissue stiffness. Mechanistically, TIMP1 expression was positively correlated with the gene expression of two predominant extracellular matrix components, tenascin C and fibronectin, both of which were also highly expressed in IDH-wild type gliomas. By introducing IDH1-R132H-containing vectors into human IDH1-wild type glioma cells to obtain an IDH1-mutant cell line, we found that IDH1 mutation increased the TIMP1 promoter methylation through methylation-specific PCR. More importantly, IDH1-R132H mutation decreased both the expression of TIMP1, fibronectin, tenascin C, and the tumor tissue stiffness in IDH1-mutant glioma xenografts in contrast to IDH1-wild type counterparts. Moreover, TIMP1 knockdown in IDH-wild type glioma cells inhibited the expression of tenascin C and fibronectin, and decreased tissue stiffness in intracranial glioma xenografts. Conclusively, we revealed an IDH mutation status-mediated mechanism in regulating glioma tissue stiffness through modulating TIMP1 and downstream extracellular matrix components.

Sorsby fundus dystrophy (SFD): A narrative review

Sorsby fundus dystrophy (SFD) is a rare autosomal dominant disorder with complete penetrance affecting the macula. This is caused by a mutation in the TIMP-3. This objective narrative review aims to provide an overview of the pathophysiology, current treatment modalities, and future perspectives. A literature search was performed using "PubMed," "Web of Science," "Scopus," "ScienceDirect," "Google Scholar," "medRxiv," and "bioRxiv." The molecular mechanisms underlying SFD are not completely understood. Novel advancements in cell culture techniques, including induced pluripotent stem cells, may enable more reliable modeling of SFD. These cell culture techniques aim to shed more light on the pathophysiology of SFD, and hopefully, this may lead to the future development of treatment strategies for SFD. Currently, no gene therapy is available. The main treatment is the use of anti-vascular endothelial growth factors (anti-VEGF) to treat secondary choroidal neovascular membrane (CNV), which is a major complication observed in this condition. If CNV is detected and treated promptly, patients with SFD have a good chance of maintaining a functional central vision. Other treatment modalities have been tried but have shown limited benefit, and therefore, have not managed to be more widely accepted. In summary, although there is no definitive cure yet, the use of anti-VEGF treatment for secondary CNV has provided the opportunity to maintain functional vision in individuals with SFD, provided CNV is detected and treated early.

Differential Expression and Localization of ADAMTS Proteinases in Proliferative Diabetic Retinopathy

We analyzed the expression of ADAMTS proteinases ADAMTS-1, -2, -4, -5 and -13; their activating enzyme MMP-15; and the degradation products of proteoglycan substrates versican and biglycan in an ocular microenvironment of proliferative diabetic retinopathy (PDR) patients. Vitreous samples from PDR and nondiabetic patients, epiretinal fibrovascular membranes from PDR patients, rat retinas, retinal Müller glial cells and human retinal microvascular endothelial cells (HRMECs) were studied. The levels of ADAMTS proteinases and MMP-15 were increased in the vitreous from PDR patients. Both full-length and cleaved activation/degradation fragments of ADAMTS proteinases were identified. The amounts of versican and biglycan cleavage products were increased in vitreous from PDR patients. ADAMTS proteinases and MMP-15 were localized in endothelial cells, monocytes/macrophages and myofibroblasts in PDR membranes, and ADAMTS-4 was expressed in the highest number of stromal cells. The angiogenic activity of PDR membranes correlated significantly with levels of ADAMTS-1 and -4 cellular expression. ADAMTS proteinases and MMP-15 were expressed in rat retinas. ADAMTS-1 and -5 and MMP-15 levels were increased in diabetic rat retinas. HRMECs and Müller cells constitutively expressed ADAMTS proteinases but not MMP-15. The inhibition of NF-κB significantly attenuated the TNF-α-and-VEGF-induced upregulation of ADAMTS-1 and -4 in a culture medium of HRMECs and Müller cells. In conclusion, ADAMTS proteinases, MMP-15 and versican and biglycan cleavage products were increased in the ocular microenvironment of patients with PDR.

Swept-Source Optical Coherence Tomography Detection of Bruch's Membrane and Choriocapillaris Abnormalities in Sorsby Macular Dystrophy

PURPOSE

Swept-source optical coherence tomography angiography (SS-OCTA) was used to analyze Bruch's membrane (BM) and choriocapillaris (CC) abnormalities in undiagnosed family members with Sorsby macular dystrophy (SMD).

METHODS

In a family with SMD (TIMP3 Tyr191Cys), SS-OCTA imaging was performed using the 6X6mm scan patter and previously validated algorithms to detect abnormalities in BM and the CC, as well as the presence of reticular pseudodrusen (RPD) and macular neovascularization (MNV). Genetic analyses were performed for TIMP3 mutations.

RESULTS

Of eight family members, two were previously diagnosed with SMD and six were asymptomatic. SS-OCTA imaging of the 33-year-old proband revealed type 1 MNV in the left eye and bilateral RPD, thickening of BM, CC thinning, and increases in CC flow deficits (FDs). A TIMP3 mutation was confirmed. His niece, despite having no clinical evidence of SMD, showed BM thickening and CC thinning on SS-OCTA. A TIMP3 mutation was confirmed. The proband's younger nephew and niece also carried the TIMP3 mutation without clinical evidence of SMD. Two additional members had normal exams, unremarkable SS-OCTA findings, and no TIMP3 mutation.

CONCLUSIONS

SS-OCTA imaging can detect BM and CC abnormalities in vivo in subjects unaware of their TIMP3 status in a family with SMD.

Vascularized Co-Culture Clusteroids of Primary Endothelial and Hep-G2 Cells Based on Aqueous Two-Phase Pickering Emulsions

Three-dimensional cell culture has been extensively involved in biomedical applications due to its high availability and relatively mature biochemical properties. However, single 3D cell culture models based on hydrogel or various scaffolds do not meet the more in-depth requirements of in vitro models. The necrotic core formation inhibits the utilization of the 3D cell culture ex vivo as oxygen permeation is impaired in the absence of blood vessels. We report a simple method to facilitate the formation of angiogenic HUVEC (human umbilical vein endothelial cells) and Hep-G2 (hepatocyte carcinoma model) co-culture 3D clusteroids in a water-in-water (w/w) Pickering emulsions template which can overcome this limitation. This method enabled us to manipulate the cells proportion in order to achieve the optimal condition for stimulating the production of various angiogenic protein markers in the co-cultured clusteroids. The HUVEC cells respond to the presence of Hep-G2 cells and their byproducts by forming endothelial cell sprouts in Matrigel without the exogenous addition of vascular endothelial growth factor (VEGF) or other angiogenesis inducers. This culture method can be easily replicated to produce other types of cell co-culture spheroids. The w/w Pickering emulsion template can facilitate the fabrication of 3D co-culture models to a great extent and be further utilized in drug testing and tissue engineering applications.

Therapeutic Potential of Cannabinoids on Tumor Microenvironment: A Molecular Switch in Neoplasia Transformation

The efficacy of chemotherapy depends on the tumor microenvironment. This microenvironment consists of a complex cellular network that can exert both stimulatory and inhibitory effects on tumor genesis. Given the increasing interest in the effectiveness of cannabis, cannabinoids have gained much attention as a potential chemotherapy drug. Cannabinoids are a group of marker compounds found in Cannabis sativa L., more commonly known as marijuana, a psychoactive drug used since ancient times for pain management. Although the anticancer potential of C. sativa, has been recognized previously, increased attention was generated after discovering the endocannabinoid system and the successful production of cannabinoid receptors. In vitro and in vivo studies on various tumor models have shown therapeutic efficiency by modifying the tumor microenvironment. However, despite extensive attention regarding potential therapeutic implications of cannabinoids, considerable clinical and preclinical analysis is needed to adequately define the physiological, pharmacological, and medicinal aspects of this range of compounds in various disorders covered in this review. This review summarizes the key literature surrounding the role of cannabinoids in the tumor microenvironment and their future promise in cancer treatment.

New Frontiers in Cancer Imaging and Therapy Based on Radiolabeled Fibroblast Activation Protein Inhibitors: A Rational Review and Current Progress

Over the past decade, the tumor microenvironment (TME) has become a new paradigm of cancer diagnosis and therapy due to its unique biological features, mainly the interconnection between cancer and stromal cells. Within the TME, cancer-associated fibroblasts (CAFs) demonstrate as one of the most critical stromal cells that regulate tumor cell growth, progression, immunosuppression, and metastasis. CAFs are identified by various biomarkers that are expressed on their surfaces, such as fibroblast activation protein (FAP), which could be utilized as a useful target for diagnostic imaging and treatment. One of the advantages of targeting FAP-expressing CAFs is the absence of FAP expression in quiescent fibroblasts, leading to a controlled targetability of diagnostic and therapeutic compounds to the malignant tumor stromal area using radiolabeled FAP-based ligands. FAP-based radiopharmaceuticals have been investigated strenuously for the visualization of malignancies and delivery of theranostic radiopharmaceuticals to the TME. This review provides an overview of the state of the art in TME compositions, particularly CAFs and FAP, and their roles in cancer biology. Moreover, relevant reports on radiolabeled FAP inhibitors until the year 2021 are highlighted-as well as the current limitations, challenges, and requirements for those radiolabeled FAP inhibitors in clinical translation.

Dynamic Expression of Membrane Type 1-Matrix Metalloproteinase (Mt1-mmp/Mmp14) in the Mouse Embryo

MT1-MMP/MMP14 belongs to a subgroup of the matrix metalloproteinases family that presents a transmembrane domain, with a cytosolic tail and the catalytic site exposed to the extracellular space. Deficient mice for this enzyme result in early postnatal death and display severe defects in skeletal, muscle and lung development. By using a transgenic line expressing the LacZ reporter under the control of the endogenous Mt1-mmp promoter, we reported a dynamic spatiotemporal expression pattern for Mt1-mmp from early embryonic to perinatal stages during cardiovascular development and brain formation. Thus, Mt1-mmp shows expression in the endocardium of the heart and the truncus arteriosus by E8.5, and is also strongly detected during vascular system development as well as in endothelial cells. In the brain, LacZ reporter expression was detected in the olfactory bulb, the rostral cerebral cortex and the caudal mesencephalic tectum. LacZ-positive cells were observed in neural progenitors of the spinal cord, neural crest cells and the intersomitic region. In the limb, Mt1-mmp expression was restricted to blood vessels, cartilage primordium and muscles. Detection of the enzyme was confirmed by Western blot and immunohistochemical analysis. We suggest novel functions for this metalloproteinase in angiogenesis, endocardial formation and vascularization during organogenesis. Moreover, Mt1-mmp expression revealed that the enzyme may contribute to heart, muscle and brain throughout development.

Visual Outcome after Intravitreal Anti-VEGF Therapy for Macular Neovascularisation Secondary to Sorsby's Fundus Dystrophy: A Systematic Review

The aim of this paper is to summarise our own and to review published experience regarding the long-term outcome of intravitreal treatment for macular neovascularisation (MNV) secondary to Sorsby's fundus dystrophy (SFD). A systematic literature search using the MeSH terms [Sorsby] and [anti-vascular endothelial growth factor (VEGF)] was conducted in NCBI/PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), ScienceDirect, Google Scholar and ClinicalTrials.gov to identify publications reporting anti-VEGF treatment outcomes in SFD. Treatment outcomes were extracted for this meta-analysis from 14 publications and an own patient reporting a total of 31 cases with a mean follow-up (FU) of 54 months. Both eyes were affected in ten (32.3%) instances. Heterogenous reporting limited the comparability of the outcomes. All papers in common, however, reported satisfied to excellent responses to anti-VEGF therapy if patients were diagnosed and treated immediately after onset of symptoms. Of 20 eyes, for which visual acuity was reported before and after treatment, five worsened and seven improved by more than 1 line, whereas eight eyes maintained their function by end of the follow up, and 11 eyes (55%) maintained a driving vision (Snellen VA ≥ 0.5). Of six eyes with a VA < 0.5, VA improved in one to VA ≥ 0.5, whereas of 14 eyes with an initial VA ≥ 0.5, this dropped to <0.5 despite therapy. In MNV secondary to SFD, the delay between first symptoms and access to anti-VEGF treatment determines subretinal scar formation and thereby, functional prognosis. If treated early, this is generally favourable under regular controls and a consequent anti-VEGF treatment of MNV activity.

Importance of Altered Gene Expression of Metalloproteinases 2, 9, and 16 in Acute Myeloid Leukemia: Preliminary Study

Acute myeloid leukemia is a group of hematological neoplasms characterized by a heterogeneous course and high mortality. The important factor in the neoplastic process is metalloproteinases, proteolytic enzymes capable of degrading various components of the extracellular matrix, which take an active part in modifying the functioning of the cell, including transformation to cancer cell. They interact with numerous signaling pathways responsible for the process of cell growth, proliferation, or apoptosis. In the present study, changes in the expression of MMP2, MMP9, and MMP16 genes between patients with AML and people without cancer were examined. The impact of cytogenetic changes in neoplastic cells on the expression level of MMP2, MMP9, and MMP16 was also assessed, as well as the impact of the altered expression on the effectiveness of the first cycle of remission-inducing therapy. To evaluate the expression of all studied genes MMP2, MMP9, and MMP16, SYBR Green-based real-time PCR method was used; the reference gene was GAPDH. For two investigated genes MMP2 and MMP16, the lower expression level was observed in patients with AML when compared to healthy people. The MMP9 gene expression level did not differ between patients with AML and healthy individuals which may indicate a different regulation of gene expression in acute myeloid leukemia. However, no correlation was observed between the genes' expression of all tested metalloproteinases and the result of cytoreductive treatment or the presence of cytogenetic changes. The obtained results show that the expression of MMP2 and MMP16 genes is reduced while the expression of MMP9 is unchanged in patients with acute myeloid leukemia. This may indicate a different regulation of the expression of these genes, and possible disruptions in gene transcription or posttranscriptional mechanisms in the MMP2 and MMP16 genes, however, do not affect the level of MMP9 expression. Obtained results in AML patients are in contrary to various types of solid tumors where increased expression is usually observed.

Relapse of pathological angiogenesis: functional role of the basement membrane and potential treatment strategies

Blinding eye diseases such as corneal neovascularization, proliferative diabetic retinopathy, and age-related macular degeneration are driven by pathological angiogenesis. In cancer, angiogenesis is key for tumor growth and metastasis. Current antiangiogenic treatments applied clinically interfere with the VEGF signaling pathway-the main angiogenic pathway-to inhibit angiogenesis. These treatments are, however, only partially effective in regressing new pathologic vessels, and the disease relapses following cessation of treatment. Moreover, the relapse of pathological angiogenesis can be rapid, aggressive and more difficult to treat than angiogenesis in the initial phase. The manner in which relapse occurs is poorly understood; however, recent studies have begun to shed light on the mechanisms underlying the revascularization process. Hypotheses have been generated to explain the rapid angiogenic relapse and increased resistance of relapsed disease to treatment. In this context, the present review summarizes knowledge of the various mechanisms of disease relapse gained from different experimental models of pathological angiogenesis. In addition, the basement membrane-a remnant of regressed vessels-is examined in detail to discuss its potential role in disease relapse. Finally, approaches for gaining a better understanding of the relapse process are discussed, including prospects for the management of relapse in the context of disease.

Ticagrelor Ameliorates Bleomycin-Induced Pulmonary Fibrosis in Rats by Inhibition of TGF-β1/Smad3 and PI3K/AKT/mTOR Pathways

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a serious disease with high mortality rate. Activation of transforming growth factor (TGF)-β1 production and signalling is considered the corner stone in the epithelial-mesenchymal transition (EMT) process. EMT plays a central role in development of fibrosis in many organs including the lungs. Activated platelets are an important source of TGF-β1 and play a pivotal role in EMT and fibrosis process. The antiplatelet, ticagrelor was previously found to inhibit the EMT in different types of cancer cells, but its ability to serve as an anti-pulmonary fibrosis (PF) agent was not previously investigated.

OBJECTIVE

In this study, we aim to investigate the potential ability of ticagrelor to ameliorate bleomycin-induced fibrosis in rats.

METHODS

PF was induced in rats by intratracheal BLM at a dose of 3 mg/kg. The effect of daily daily 20 mg/kg oral ticagrelor on different histological and biochemical parameters of fibrosis was investigated.

RESULTS

Our results revealed that ticagrelor can alleviate lung fibrosis. We found that ticagrelor inhibited TGF-β1 production and suppressed Smad3 activation and signaling pathway with subsequent inhibition of Slug and Snail. In addition, ticagrelor antagonized PI3K/AKT/mTOR pathway signaling. Moreover, ticagrelor inhibited the EMT that revealed by its ability to up-regulate the epithelial markers as E-cadherin (E-cad) and to decrease the expression of the mesenchymal markers as vimentin (VIM) and alpha-smooth muscle actin (α-SMA).

CONCLUSION

Our results suggest that the P2Y12 inhibitor, ticagrelor may have a therapeutic potential in reducing the progression of PF.

The Roles of Matrix Metalloproteinases and Their Inhibitors in Human Diseases

Matrix metalloproteinases (MMPs) are a family of zinc-dependent extracellular matrix (ECM) remodeling endopeptidases that have the capacity to degrade almost every component of the ECM. The degradation of the ECM is of great importance, since it is related to embryonic development and angiogenesis. It is also involved in cell repair and the remodeling of tissues. When the expression of MMPs is altered, it can generate the abnormal degradation of the ECM. This is the initial cause of the development of chronic degenerative diseases and vascular complications generated by diabetes. In addition, this process has an association with neurodegeneration and cancer progression. Within the ECM, the tissue inhibitors of MMPs (TIMPs) inhibit the proteolytic activity of MMPs. TIMPs are important regulators of ECM turnover, tissue remodeling, and cellular behavior. Therefore, TIMPs (similar to MMPs) modulate angiogenesis, cell proliferation, and apoptosis. An interruption in the balance between MMPs and TIMPs has been implicated in the pathophysiology and progression of several diseases. This review focuses on the participation of both MMPs (e.g., MMP-2 and MMP-9) and TIMPs (e.g., TIMP-1 and TIMP-3) in physiological processes and on how their abnormal regulation is associated with human diseases. The inclusion of current strategies and mechanisms of MMP inhibition in the development of new therapies targeting MMPs was also considered.

Cerebrospinal fluid cytokines in metastatic group 3 and 4 medulloblastoma

Background

Metastatic medulloblastoma (MB) portends a poor prognosis. Amongst the 4 molecular subtypes, Group 3 and Group 4 patients have a higher incidence of metastatic disease, especially involving the neuroaxis. At present, mechanisms underlying MB metastasis remain elusive. Separately, inflammation has been implicated as a key player in tumour development and metastasis. Cytokines and their inflammation-related partners have been demonstrated to act on autocrine and, or paracrine pathways within the tumour microenvironment for various cancers. In this study, the authors explore the involvement of cerebrospinal fluid (CSF) cytokines in Group 3 and 4 MB patients with disseminated disease.

Methods

This is an ethics approved, retrospective study of prospectively collected data based at a single institution. Patient clinicpathological data and corresponding bio-materials are collected after informed consent. All CSF samples are interrogated using a proteomic array. Resultant expression data of selected cytokines are correlated with each individual’s clinical information. Statistical analysis is employed to determine the significance of the expression of CSF cytokines in Group 3 and 4 patients with metastatic MB versus non-metastatic MB.

Results

A total of 10 patients are recruited for this study. Median age of the cohort is 6.6 years old. Based on Nanostring gene expression analysis, 5 patients have Group 3 as their molecular subtype and the remaining 5 are Group 4. There are 2 non-metastatic versus 3 metastatic patients within each molecular subtype. Proteomic CSF analysis of all patients for both subtypes show higher expression of CCL2 in the metastatic group versus the non-metastatic group. Within the Group 3 subtype, the MYC-amplified Group 3 MB patients with existing and delayed metastases express higher levels of CXCL1, IL6 and IL8 in their CSF specimens at initial presentation. Furthermore, a longitudinal study of metastatic Group 3 MB observes that selected cytokines are differentially expressed in MYC-amplified metastatic Group 3 MB, in comparison to the non-MYC amplified metastatic Group 3 MB patient.

Conclusion

This study demonstrates higher expression of selected CSF cytokines, in particular CCL2, in metastatic Group 3 and 4 MB patients. Although our results are preliminary, they establish a proof-of-concept basis for continued work in a larger cohort of patients affected by this devastating disease.

Role of Extracellular Matrix in Gastrointestinal Cancer-Associated Angiogenesis

Gastrointestinal tumors are responsible for more cancer-related fatalities than any other type of tumors, and colorectal and gastric malignancies account for a large part of these diseases. Thus, there is an urgent need to develop new therapeutic approaches to improve the patients' outcome and the tumor microenvironment is a promising arena for the development of such treatments. In fact, the nature of the microenvironment in the different gastrointestinal tracts may significantly influence not only tumor development but also the therapy response. In particular, an important microenvironmental component and a potential therapeutic target is the vasculature. In this context, the extracellular matrix is a key component exerting an active effect in all the hallmarks of cancer, including angiogenesis. Here, we summarized the current knowledge on the role of extracellular matrix in affecting endothelial cell function and intratumoral vascularization in the context of colorectal and gastric cancer. The extracellular matrix acts both directly on endothelial cells and indirectly through its remodeling and the consequent release of growth factors. We envision that a deeper understanding of the role of extracellular matrix and of its remodeling during cancer progression is of chief importance for the development of new, more efficacious, targeted therapies.

Regulation of matrix metalloproteinases 2 and 9 in corneal neovascularization

Corneal neovascularization (CNV), a pathological process of angiogenesis, can lead to serious consequences in the cornea. CNV is generally proved to associate with inflammation in the cornea closely, which is mainly elicited by the disruption of equilibrium between angiogenic and antiangiogenic factors. Angiogenic factors including vascular endothelial growth factors (VEGFs), basic fibroblast growth factors (bFGFs), and matrix metalloproteinases (MMPs) are vital factors in the formation of CNV. Especially VEGFs are convinced to be the core angiogenic factors in CNV, and MMPs are proved to exert dual effects on the process. Strikingly, matrix metalloproteinase 2 (MMP-2) and matrix metalloproteinase 9 (MMP-9) are determined to play key roles in the formation of CNV, while the mechanism is still vague. In this review, the latest researches are reviewed to discuss the role of MMP-2 and MMP-9 in CNV, respectively, and some inhibitors of them are presented. We hope to provide a new direction of drug research for CNV.

Silver Decorated Mesoporous Carbons for the Treatment of Acute and Chronic Wounds, in a Tissue Regeneration Context

INTRODUCTION

Silver decorated mesoporous carbons are interesting systems that may offer effective solutions for advanced wound care products by combining the well-known anti-microbial activity of silver nanoparticles with the versatile properties of ordered mesoporous carbons. Silver is being used as a topical antimicrobial agent, especially in wound repair. However, while silver shows bactericidal properties, it is also cytotoxic at high concentrations. Therefore, the incorporation of silver into ordered mesoporous carbons allows to exploit both silver's biological effects and mesoporous carbons' biocompatibility and versatility with the purpose of conceiving silver-doped materials in light of the growing health concern in wound care.

METHODS

The wound healing potential of an ordered mesoporous carbon also doped with two different loadings of silver nanoparticles (2 wt% and 10 wt%), was investigated through a biological assessment study based on different assays (cell viability, inflammation, antibacterial tests, macrophage-conditioned fibroblast and human keratinocyte cell cultures).

RESULTS

The results show silver-doped ordered mesoporous carbons to positively condition cell viability, with a cell viability percentage >70% even for 10 wt% Ag, to modulate the expression of inflammatory cytokines and of genes involved in tissue repair (KRT6a, VEGFA, IVN) and remodeling (MMP9, TIMP3) in different cell systems. Furthermore, along with the biocompatibility and the bioactivity, the silver-doped ordered mesoporous carbons still retain an antibacterial effect, as shown by a maximum of 13.1% of inhibited area in the Halo test. The obtained results clearly showed that the silver-doped ordered mesoporous carbons exhibit both good biocompatibility and antibacterial effect with enhanced re-epithelialization, angiogenesis promotion and tissue regeneration.

DISCUSSION

These findings suggest that the exceptional properties of silver-doped ordered mesoporous carbons could be exploited in the treatment of acute and chronic wounds and that such carbon materials could be potential candidates for use in medical devices for wound healing purposes, in particular, the 10 wt% loading, as the results showed to be the most effective.

Regulatory T Cells Induce Metastasis by Increasing Tgf-β and Enhancing the Epithelial–Mesenchymal Transition

Malignant melanoma is the most aggressive form of skin cancer; a substantial percentage of patients present with distant metastases. However, the mechanism of metastasis is not well understood. Here, we demonstrate that the administration of exogenous regulatory T cells (Tregs) into melanoma tumor-bearing mice results in a significant increase in lung metastasis. An increase in the invasive and metastatic phenotype of melanoma was mediated by cell-to-cell contact between melanoma cells and Tregs, which elevated the expression level of transforming growth factor-β (TGF-β) and the subsequent induction of the epithelial-to-mesenchymal transition (EMT).B16-BL6 melanoma tumors co-cultured with Tregs showed a larger population of migrating cells compared to B16-BL6 tumors cultured without Tregs. Additionally, the injection of exogenous Tregs into B16-BL6 melanoma tumors led to the recruitment and infiltration of endogenous Tregs into tumor tissues, thus increasing the overall Treg percentage in the tumor infiltrating lymphocyte population. Collectively, our findings propose novel mechanisms in which exogenous Treg-dependent upregulation of TGF-β and mesenchymal markers is important for augmenting the migration capacity and invasiveness of melanoma, thereby contributing to the metastasis.

Downregulation of ADAMTS18 May Serve as a Poor Prognostic Biomarker for Cervical Cancer Patients

ADAMTS18 is a member of ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) family proteins which have been found to play important roles in cancer progression and metastasis in different cancer types. The present study aims at evaluating the prognostic significance of ADAMTS18 in cervical cancer. The expression levels of ADAMTS18 was evaluated by real-time PCR in normal (N=28) and cervical cancer tissues from patients at different stages as well as in tumor tissues from 35 cervical cancer patients with primary cancer and 29 patients with metastasis. The correlation between serum ADAMTS18 expression levels and clinicopathologic features or overall survival of cervical cancer patients was analyzed. ADAMTS18 expression levels were significantly decreased in cervical cancer tissues compared with normal tissues and it decreased gradually from early stage to late stage. Low expression of ADAMTS18 was positively associated with high tumor stage (P=0.0239), positive lymph node metastasis (P=0.0388), and distant metastasis (P=0.0004). Tissue levels of ADAMTS18 in patients with primary cancer were significantly lower compared with those with metastasis. Moreover, patients with low ADAMTS18 expression levels had shorter overall survival (P=0.0119) or disease-free survival (P=0.0033). Multivariate analysis demonstrated that ADAMTS18 was an independent prognostic factor for cervical cancer. Our study suggests that ADAMTS18 is downregulated in cervical cancer and ADAMTS18 may serve as a potential prognostic biomarker for cervical cancer.

Exploring the Antiangiogenic Potential of Solomonamide A Bioactive Precursors: In Vitro and in Vivo Evidences of the Inhibitory Activity of Solo F-OH During Angiogenesis

Marine sponges are a prolific source of bioactive compounds. In this work, the putative antiangiogenic potential of a series of synthetic precursors of Solomonamide A, a cyclic peptide isolated from a marine sponge, was evaluated. By means of an in vitro screening, based on the inhibitory activity of endothelial tube formation,&nbsp;the compound Solo F-OH was selected for a deeper characterization of its antiangiogenic potential. Our results indicate that Solo F-OH is able to inhibit some key steps of the angiogenic process, including the proliferation,&nbsp;migration, and invasion of endothelial cells, as well as diminish their capability to degrade the extracellular matrix proteins. The antiangiogenic potential of Solo F-OH was confirmed by means of two different in vivo models: the chorioallantoic membrane (CAM) and the zebrafish yolk membrane (ZFYM) assays. The reduction in ERK1/2 and Akt phosphorylation in endothelial cells treated with Solo F-OH denotes that this compound could target the upstream components that are common to both pathways. Taken together, our results show a new and interesting biological activity of Solo F-OH as an inhibitor of the persistent and deregulated angiogenesis that characterizes cancer and other pathologies.

Transgelin induces dysfunction of fetal endothelial colony-forming cells from gestational diabetic pregnancies

Fetal exposure to gestational diabetes mellitus (GDM) predisposes children to future health complications including hypertension and cardiovascular disease. A key mechanism by which these complications occur is through the functional impairment of vascular progenitor cells, including endothelial colony-forming cells (ECFCs). Previously, we showed that fetal ECFCs exposed to GDM have decreased vasculogenic potential and altered gene expression. In this study, we evaluate whether transgelin (TAGLN), which is increased in GDM-exposed ECFCs, contributes to vasculogenic dysfunction. TAGLN is an actin-binding protein involved in the regulation of cytoskeletal rearrangement. We hypothesized that increased TAGLN expression in GDM-exposed fetal ECFCs decreases network formation by impairing cytoskeletal rearrangement resulting in reduced cell migration. To determine if TAGLN is required and/or sufficient to impair ECFC network formation, TAGLN was reduced and overexpressed in ECFCs from GDM and uncomplicated pregnancies, respectively. Decreasing TAGLN expression in GDM-exposed ECFCs improved network formation and stability as well as increased migration. In contrast, overexpressing TAGLN in ECFCs from uncomplicated pregnancies decreased network formation, network stability, migration, and alignment to laminar flow. Overall, these data suggest that increased TAGLN likely contributes to the vasculogenic dysfunction observed in GDM-exposed ECFCs, as it impairs ECFC migration, cell alignment, and network formation. Identifying the molecular mechanisms underlying fetal ECFC dysfunction following GDM exposure is key to ascertain mechanistically the basis for cardiovascular disease predisposition later in life.

Epirubicin suppresses proliferative and metastatic potential by downregulating transforming growth factor-β-induced expression in urothelial carcinoma

Transforming growth factor‐β‐induced (TGFΒI) is considered to be a vital gene in several carcinomas. In this study we determined the effect of TGFBI on the proliferative and metastatic potential of human urothelial carcinoma (UC) cells as well as its mRNA and protein expression, which were detected by RT‐PCR and western blot, respectively. UC cell proliferation was analyzed by WST‐1 assay and Hoechst 33258 staining. The effect of TGFBI on UC cell metastasis was analyzed using adhesion, migration and invasion assays. We found that TGFBI increased the proliferation of UC cells. Moreover, TGFBI enhanced the adhesion, migration and invasion of UC cells by upregulating MMP‐2, MMP‐9 and calpain‐2 expression. We evaluated the effect of Epirubicin (EPI) on the regulation of TGFBI expression and found that TGFBI acts as a downstream target of EPI and is suppressed by EPI in UC cells. EPI is more effective in inhibiting the proliferation and metastasis of UC cells with high TGFBI expression. This study demonstrates that TGFBI might lead to tumorigenesis and progression of UC and those cells with high TGFBI expression may be vulnerable to relapse. EPI could prove to be a therapeutic option in patients with high TGFBI expressing UC cells.

Surface Functionalization and Targeting Strategies of Liposomes in Solid Tumor Therapy: A Review

Surface functionalization of liposomes can play a key role in overcoming the current limitations of nanocarriers to treat solid tumors, i.e., biological barriers and physiological factors. The phospholipid vesicles (liposomes) containing anticancer agents produce fewer side effects than non-liposomal anticancer formulations, and can effectively target the solid tumors. This article reviews information about the strategies for targeting of liposomes to solid tumors along with the possible targets in cancer cells, i.e., extracellular and intracellular targets and targets in tumor microenvironment or vasculature. Targeting ligands for functionalization of liposomes with relevant surface engineering techniques have been described. Stimuli strategies for enhanced delivery of anticancer agents at requisite location using stimuli-responsive functionalized liposomes have been discussed. Recent approaches for enhanced delivery of anticancer agents at tumor site with relevant surface functionalization techniques have been reviewed. Finally, current challenges of functionalized liposomes and future perspective of smart functionalized liposomes have been discussed.

Evaluation of Tumor Vasculature Using a Syngeneic Tumor Model in Wild-Type and Genetically Modified Mice

The relevance of tumor vasculature has been extensively recognized, and it is still the focus of numerous lines of research for basic, translational, and clinical scientists. Indeed, the knowledge of some of its regulatory mechanisms has provoked the generation of ongoing cancer therapies. Within the context of the tumor microenvironment, the information that the analysis of the vasculature provides is very valuable, and it might reveal not just its quality and the response against a specific therapy but also its close relationship with neighboring stromal and tumor players.Studies during last decades already supported the contribution of extracellular proteases in neovascularization events, including ADAMTS. However, deeper analyses are still required to better understand the modulation of their proteolytic activity in the tumor microenvironment. Future studies will clearly benefit from existing and ongoing genetically modified mouse models.Here we emphasize the use of syngeneic models to study the vasculature during tumor progression, supported by their intact immunocompetent capacities and also by the range of possibilities to play with engineered mice and with modified tumor cells. Although various high-tech and sophisticated approaches have already been reported to evaluate tumor neovascularization, here we describe a simple and easily reproduced methodology based in the immunofluorescence detection of vascular-specific molecules. A final in silico analysis guarantees an unbiased quantification of tumor vasculature under different conditions.

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.

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.

STAT3-mediated activation of miR-21 is involved in down-regulation of TIMP3 and neovascularization in the ischemic retina

Retinal neovascularization (RNV) is a sight threatening complication of ischemic retinopathies with limited therapeutic options. The transcription factor signal transducer and activator of transcription 3 (STAT3) has been shown to play a crucial role in promoting RNV. However, manipulating of STAT3 activity can cause significant adverse side effects due to its neurotrophic properties. In this study, we identified microRNA-21 (miR-21) as a downstream effector of STAT3 activity in the ischemic retinas and determined its role in promoting RNV through inhibition of its molecular target, the tissue inhibitor of matrix metalloproteinases 3 (TIMP3). Using human retinal endothelial cells (HREC) exposed to hypoxia and a mouse model of oxygen-induced retinopathy (OIR), we found that TIMP3 expression was significantly decreased at both mRNA and protein levels and this paralleled the activation of STAT3 and up-regulation of miR-21. Moreover, TIMP3 expression was restored by knockdown of STAT3 or blocking of miR-21 in HREC, thus, confirming TIMP3 as a downstream target of STAT3/miR-21 pathway. Finally, in a mouse model of OIR, blockade of miR-21 by a specific antisense (a.miR-21), halted RNV and this effect was associated with rescuing of TIMP3 expression. Our data show that miR-21 mediates STAT3 pro-angiogenic effects in the ischemic retina, thus suggesting its blockade as a potential therapy to prevent/halt RNV.

Matrix Metalloproteinases, Vascular Remodeling, and Vascular Disease

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that degrade various proteins in the extracellular matrix (ECM). Typically, MMPs have a propeptide sequence, a catalytic metalloproteinase domain with catalytic zinc, a hinge region or linker peptide, and a hemopexin domain. MMPs are commonly classified on the basis of their substrates and the organization of their structural domains into collagenases, gelatinases, stromelysins, matrilysins, membrane-type (MT)-MMPs, and other MMPs. MMPs are secreted by many cells including fibroblasts, vascular smooth muscle (VSM), and leukocytes. MMPs are regulated at the level of mRNA expression and by activation through removal of the propeptide domain from their latent zymogen form. MMPs are often secreted in an inactive proMMP form, which is cleaved to the active form by various proteinases including other MMPs. MMPs degrade various protein substrates in ECM including collagen and elastin. MMPs could also influence endothelial cell function as well as VSM cell migration, proliferation, Ca²⁺ signaling, and contraction. MMPs play a role in vascular tissue remodeling during various biological processes such as angiogenesis, embryogenesis, morphogenesis, and wound repair. Alterations in specific MMPs could influence arterial remodeling and lead to various pathological disorders such as hypertension, preeclampsia, atherosclerosis, aneurysm formation, as well as excessive venous dilation and lower extremity venous disease. MMPs are often regulated by endogenous tissue inhibitors of metalloproteinases (TIMPs), and the MMP/TIMP ratio often determines the extent of ECM protein degradation and tissue remodeling. MMPs may serve as biomarkers and potential therapeutic targets for certain vascular disorders.

Sorsby fundus dystrophy - A review of pathology and disease mechanisms

Sorsby fundus dystrophy (SFD) is an autosomal dominant macular dystrophy with an estimated prevalence of 1 in 220,000 and an onset of disease around the 4th to 6th decade of life. Similar to age-related macular degeneration (AMD), ophthalmoscopy reveals accumulation of protein/lipid deposits under the retinal pigment epithelium (RPE), referred to as drusen, in the eyes of patients with SFD. SFD is caused by variants in the gene for tissue inhibitor of metalloproteinases-3 (TIMP3), which has been found in drusen-like deposits of SFD patients. TIMP3 is constitutively expressed by RPE cells and, in healthy eyes, resides in Bruch's membrane. Most SFD-associated TIMP3 variants involve the gain or loss of a cysteine residue. This suggests the protein aberrantly forms intermolecular disulphide bonds, resulting in the formation of TIMP3 dimers. It has been demonstrated that SFD-associated TIMP3 variants are more resistant to turnover, which is thought to be a result of dimerisation and thought to explain the accumulation of TIMP3 in drusen-like deposits at the level of Bruch's membrane. An important function of TIMP3 within the outer retina is to regulate the thickness of Bruch's membrane. TIMP3 performs this function by inhibiting the activity of matrix metalloproteinases (MMPs), which have the function of catalysing breakdown of the extracellular matrix. TIMP3 has an additional function to inhibit vascular endothelial growth factor (VEGF) signalling and thereby to inhibit angiogenesis. However, it is unclear whether SFD-associated TIMP3 variant proteins retain these functions. In this review, we discuss the current understanding of the potential mechanisms underlying development of SFD and summarise all known SFD-associated TIMP3 variants. Cell culture models provide an invaluable way to study disease and identify potential treatments. These allow a greater understanding of RPE physiology and pathophysiology, including the ability to study the blood-retinal barrier as well as other RPE functions such as phagocytosis of photoreceptor outer segments. This review describes some examples of such recent in vitro studies and how they might provide new insights into degenerative diseases like SFD. Thus far, most studies on SFD have been performed using ARPE-19 cells or other, less suitable, cell-types. Now, induced pluripotent stem cell (iPSC) technologies allow the possibility to non-invasively collect somatic cells, such as dermal fibroblast cells and reprogram those to produce iPSCs. Subsequent differentiation of iPSCs can generate patient-derived RPE cells that carry the same disease-associated variant as RPE cells in the eyes of the patient. Use of these patient-derived RPE cells in novel cell culture systems should increase our understanding of how SFD and similar macular dystrophies develop.

Matrix Metalloproteinase Inhibitors as Investigational and Therapeutic Tools in Unrestrained Tissue Remodeling and Pathological Disorders

Matrix metalloproteinases (MMPs) are zinc-dependent proteolytic enzymes that degrade various proteins in the extracellular matrix (ECM). MMPs may also regulate the activity of membrane receptors and postreceptor signaling mechanisms and thereby affect cell function. The MMP family includes collagenases, gelatinases, stromelysins, matrilysins, membrane-type MMPs, and other MMPs. Inactive proMMPs are cleaved by other MMPs or proteases into active MMPs, which interact with various protein substrates in ECM and cell surface. MMPs regulate important biological processes such as vascular remodeling and angiogenesis and may be involved in the pathogenesis of cardiovascular disorders such as hypertension, atherosclerosis, and aneurysm. The role of MMPs is often assessed by measuring their mRNA expression, protein levels, and proteolytic activity using gel zymography. MMP inhibitors are also used to assess the role of MMPs in different biological processes and pathological conditions. MMP activity is regulated by endogenous tissue inhibitors of metalloproteinases (TIMPs), and the MMP/TIMP balance could determine the net MMP activity, ECM turnover, and tissue remodeling. Also, several synthetic MMP inhibitors have been developed. Synthetic MMP inhibitors include a large number of zinc-binding globulins (ZBGs), in addition to non-ZBGs and mechanism-based inhibitors. MMP inhibitors have been proposed as potential tools in the management of osteoarthritis, cancer, and cardiovascular disorders. However, most MMP inhibitors have broad-spectrum actions on multiple MMPs and could cause undesirable musculoskeletal side effects. Currently, doxycycline is the only MMP inhibitor approved by the Food and Drug Administration. New generation biological and synthetic MMP inhibitors may show greater MMP specificity and fewer side effects and could be useful in targeting specific MMPs, reducing unrestrained tissue remodeling, and the management of MMP-related pathological disorders.

Expression and prognostic impact of matrix metalloproteinase-2 (MMP-2) in astrocytomas

Astrocytomas are the most frequent primary brain tumors in adults, and despite aggressive treatment patients often experience recurrence. Survival decreases with increasing tumor grade, and especially patients with grade IV glioblastoma have poor prognosis due to the aggressive character of this tumor. Matrix metalloproteinase-2 (MMP-2) is an extracellular matrix degrading enzyme which has been shown to play important roles in different cancers. The aim of this study was to investigate the expression and prognostic potential of MMP-2 in astrocytomas. Tissue samples from 89 patients diagnosed with diffuse astrocytoma, anaplastic astrocytoma and glioblastoma were stained immunohistochemically using a monoclonal MMP-2 antibody. The MMP-2 intensity in cytoplasm/membrane was quantified by a trained software-based classifier using systematic random sampling in 10% of the tumor area. We found MMP-2 expression in tumor cells and blood vessels. Measurements of MMP-2 intensity increased with tumor grade, and MMP-2 expression was found to be significantly higher in glioblastomas compared to normal brain tissue (p<0.001), diffuse astrocytomas (p<0.001) and anaplastic astrocytomas (p<0.05). MMP-2 expression was associated with shorter overall survival in patients with grade II-IV astrocytic tumors (HR 1.60; 95% CI 1.03–2.48; p = 0.036). In glioblastoma, high MMP-2 was associated with poorer prognosis in patients who survived longer than 8.5 months independent of age and gender (HR 2.27; 95% CI 1.07–4.81; p = 0.033). We found a positive correlation between MMP-2 and tissue inhibitor of metalloproteinases-1 (TIMP-1), and combined MMP-2 and TIMP-1 had stronger prognostic value than MMP-2 alone also when adjusting for age and gender (HR 2.78; 95% CI 1.30–5.92; p = 0.008). These findings were validated in bioinformatics databases. In conclusion, this study indicates that MMP-2 is associated with aggressiveness in astrocytomas and may hold an unfavorable prognostic value in patients with glioblastoma.

Emodin ameliorates bleomycin-induced pulmonary fibrosis in rats by suppressing epithelial-mesenchymal transition and fibroblast activation

Aberrant activation of TGF-β1 is frequently encountered and promotes epithelial-mesenchymal transition (EMT) and fibroblast activation in pulmonary fibrosis. The present study investigated whether emodin mediates its effect via suppressing TGF-β1-induced EMT and fibroblast activation in bleomycin (BLM)-induced pulmonary fibrosis in rats. Here, we found that emodin induced apoptosis and inhibited cellular proliferation, migration and differentiation in TGF-β1-stimulated human embryonic lung fibroblasts (HELFs). Emodin suppressed TGF-β1-induced EMT in a dose- and time-dependent manner in alveolar epithelial A549 cells. Emodin also inhibited TGF-β1-induced Smad2, Smad3 and Erk1/2 activation, suggesting that Smad2/3 and Erk1/2 inactivation mediated the emodin-induced effects on TGF-β1-induced EMT. Additionally, we provided in vivo evidence suggesting that emodin apparently alleviated BLM-induced pulmonary fibrosis and improved pulmonary function by inhibiting TGF-β1 signaling and subsequently repressing EMT, fibroblast activation and extracellular matrix (ECM) deposition. Taken together, our data suggest that emodin mediates its effects mainly via inhibition of EMT and fibroblast activation and thus has a potential for the treatment of pulmonary fibrosis.

Matrix metalloproteinases in the brain and blood-brain barrier: Versatile breakers and makers

Matrix metalloproteinases are versatile endopeptidases with many different functions in the body in health and disease. In the brain, matrix metalloproteinases are critical for tissue formation, neuronal network remodeling, and blood-brain barrier integrity. Many reviews have been published on matrix metalloproteinases before, most of which focus on the two best studied matrix metalloproteinases, the gelatinases MMP-2 and MMP-9, and their role in one or two diseases. In this review, we provide a broad overview of the role various matrix metalloproteinases play in brain disorders. We summarize and review current knowledge and understanding of matrix metalloproteinases in the brain and at the blood-brain barrier in neuroinflammation, multiple sclerosis, cerebral aneurysms, stroke, epilepsy, Alzheimer's disease, Parkinson's disease, and brain cancer. We discuss the detrimental effects matrix metalloproteinases can have in these conditions, contributing to blood-brain barrier leakage, neuroinflammation, neurotoxicity, demyelination, tumor angiogenesis, and cancer metastasis. We also discuss the beneficial role matrix metalloproteinases can play in neuroprotection and anti-inflammation. Finally, we address matrix metalloproteinases as potential therapeutic targets. Together, in this comprehensive review, we summarize current understanding and knowledge of matrix metalloproteinases in the brain and at the blood-brain barrier in brain disorders.

Cathepsin L in tumor angiogenesis and its therapeutic intervention by the small molecule inhibitor KGP94

A significant proportion of breast cancer patients harbor clinically undetectable micrometastases at the time of diagnosis. If left untreated, these micro-metastases may lead to disease relapse and possibly death. Hence, there is significant interest in the development of novel anti-metastatic agents that could also curb the growth of pre-established micrometastases. Like primary tumor, the growth of metastases also is driven by angiogenesis. Although the role of cysteine protease Cathepsin L (CTSL) in metastasis associated tumor cell functions such as migration and invasion is well recognized, its role in tumor angiogenesis remains less explored. The present study examines the contribution of CTSL to breast cancer angiogenesis and evaluates the anti-angiogenic efficacy of CTSL inhibitor KGP94. CTSL semi-quantitative RT-PCR analysis on breast tissue panels revealed significant upregulation of CTSL in breast cancer patients which strongly correlated with increased relapse and metastatic incidence and poor overall survival. Preclinically, CTSL ablation using shRNA or KGP94 treatment led to a significant reduction in MDA-MB-231 tumor cell induced angiogenesis in vivo. In-vitro assessments demonstrated a significant decrease in various angiogenic properties such as endothelial cell sprouting, migration, invasion, tube formation and proliferation in the presence of KGP94. Microarray analyses revealed a significant upregulation of cell cycle related genes by CTSL. Western blot analyses further confirmed upregulation of members of the cyclin family by CTSL. Collectively, these data indicate that CTSL is an important contributor to tumor angiogenesis and that the CTSL inhibition may have therapeutic utility in the treatment of breast cancer patients.

The Angiogenic Effect of microRNA-21 Targeting TIMP3 through the Regulation of MMP2 and MMP9

microRNAs are a novel set of small, non-protein-coding nucleotide RNAs that negatively regulate the expression of target mRNAs. miRNA-21 is a microRNA that is highly enriched in endothelial cells. miRNA-21 has been shown to be a potential pro-angiogenic factor in some biological systems. Our previous study showed that the expression of miRNA-21 was up-regulated after spinal cord injury. However, the effect of miRNA-21 on angiogenesis in the spinal cord was unclear. In this study, to understand the role of miRNA-21 on injured endothelial cells exclusively, an oxygen and glucose deprivation model of endothelial cells was constructed, and the up-regulation of miRNA-21 was discovered in this model. An increased level of miRNA-21 by mimics promoted the survival, migration and tube formation of endothelial cells, which simultaneously inhibited tissue inhibitor of metalloproteinase-3 (TIMP3) expression and promoted matrix metalloproteinase-2 (MMP2) and matrix metalloproteinase-9 (MMP9) expression and secretion. A decreased level of miRNA-21 by antagomir exerted an opposite effect. As is well known, survival, migration and tube formation of endothelial cells are necessary prerequisites for angiogenesis after injury. TIMP3 was validated as a direct target of miRNA-21 by dual-luciferase reporter assay. Silencing with small interfering RNA against TIMP3 promoted tube formation and increased MMP2 and MMP9 expression at the protein level. In vivo, we found that decreased levels of miRNA-21 inhibited angiogenesis after spinal cord injury in rats using synchrotron radiation micro-computed tomography. In summary, these findings suggest that miRNA-21 has a protective effect on angiogenesis by reducing cell death and promoting cell survival, migration and tube formation via partially targeting the TIMP3 by potentially regulating MMP2 and MMP9. TIMP3 is a functional target gene. Identifying the role of miRNA-21 in the protection of angiogenesis might offer a novel therapeutic target for secondary spinal cord injury, in which angiogenesis is indispensable.

Neutrophil Elastase-Generated Fragment of Vascular Endothelial Growth Factor-A Stimulates Macrophage and Endothelial Progenitor Cell Migration

Elastase released from neutrophils as part of the innate immune system has been implicated in chronic diseases such as emphysema and cardiovascular disease. We have previously shown that neutrophil elastase targets vascular endothelial growth factor-A (VEGF) for partial degradation to generate a fragment of VEGF (VEGFf) that has distinct activities. Namely, VEGFf binds to VEGF receptor 1 but not to VEGF receptor 2 and shows altered signaling compared to intact VEGF. In the present study we investigated the chemotactic function of VEGF and VEGFf released from cells by neutrophil elastase. We found that endothelial cells migrated in response to intact VEGF but not VEGFf whereas RAW 264.7 macrophages/monocytes and embryonic endothelial progenitor cells were stimulated to migrate by either VEGF or VEGFf. To investigate the role of elastase-mediated release of VEGF from cells/extracellular matrices, a co-culture system was established. High or low VEGF producing cells were co-cultured with macrophages, endothelial or endothelial progenitor cells and treated with neutrophil elastase. Elastase treatment stimulated macrophage and endothelial progenitor cell migration with the response being greater with the high VEGF expressing cells. However, elastase treatment led to decreased endothelial cell migration due to VEGF cleavage to VEGF fragment. These findings suggest that the tissue response to NE-mediated injury might involve the generation of diffusible VEGF fragments that stimulate inflammatory cell recruitment.

Upregulation of a disintegrin and metalloprotease 8 is associated with progression and prognosis of patients with gastric cancer

A disintegrin and metalloprotease 8 (ADAM8) is involved in the tumorigenesis of several types of solid tumors. However, its exact role in gastric cancer (GC) remains unclear. The aim of this study was to evaluate the clinical significance of ADAM8 in GC and to explore its biological effects on gastric carcinogenesis. In this study, quantitative reverse transcription-polymerase chain reaction, Western blotting, and immunohistochemical staining analysis revealed that ADAM8 messenger RNA expression was significantly upregulated in GC tissues compared with noncancerous tissues (P = 0.004), and that positive ADAM8 expression is much more common in tumor tissues compared with normal tissues (P < 0.001) and is correlated with T stage (P = 0.036), N stage (P = 0.048), vessel invasion (P = 0.002), and a shorter patient overall survival (P = 0.024). In vitro assay indicated that ADAM8 overexpression promoted cell growth and increased migration and invasion abilities by decreasing the p-p38/p-extracellular regulated protein kinases (p-ERK) ratio. In conclusion, ADAM8 promotes GC cell proliferation and invasion, and its expression is positively correlated with poor survival, indicating that it might be a promising target in GC therapy.

Chitosan aerosol inhalation alleviates lipopolysaccharide- induced pulmonary fibrosis in rats

PURPOSE

Pulmonary fibrosis (PF) is an insidiously progressive scarring disorder of the alveoli and is associated with high mortality. Currently, therapies available are associated with restricted efficacy and side effects. This study aimed to investigate the effect of chitosan aerosol inhalation on lipopolysaccharide (LPS)-induced pulmonary remodeling and fibrosis in rats.

METHODS

A rat model of PF was established by intratracheal injection of LPS (5 mg/kg). Chitosan was nebulized to rats from day 4 to 28 after LPS injection. We analyzed the effect of chitosan on LPS-induced pulmonary remodeling and fibrosis by hematoxylin-eosin staining (HE), Masson staining, and the determination of the hydroxyproline content. The expression intensities of matrix metalloproteinase-3 (MMP-3) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were analyzed by western blots.

RESULTS

Histological assessments showed that chitosan aerosol inhalation attenuated the fibrotic changes in LPS-induced PF in rats. Compared with the LPS group, the fibrosis parameters were significantly improved in the LPS + chitosan group (LCh group), although not as good as those of the control group. The expressions of MMP-3 and TIMP-1 in the LCh group were markedly less than that of the LPS group on the 28th day.

CONCLUSIONS

Our findings show that chitosan aerosol inhalation inhibits the expression of MMP-3 and TIMP-1, and ameliorates LPS-induced pulmonary remodeling and fibrosis in rats.

Membrane-type matrix metalloproteinases: Their functions and regulations

Membrane-type matrix metalloproteinases (MT-MMPs) form a subgroup of the matrix metalloproteinase (MMP) family, and there are 6 MT-MMPs in humans. MT-MMPs are further sub-classified into type I transmembrane-type (MT1, -MT2-, MT3- and MT5-MMPs) and glycosylphosphatidylinositol (GPI)-anchored type (MT4- and MT6-MMPs). In either case MT-MMPs are tethered to the plasma membrane, and this cell surface expression provides those enzymes with unique functionalities affecting various cellular behaviours. Among the 6 MT-MMPs, MT1-MMP is the most investigated enzyme and many of its roles and regulations have been revealed to date, but the potential roles and regulatory mechanisms of other MT-MMPs are gradually getting clearer as well. Further investigations of MT-MMPs are likely to reveal novel pathophysiological mechanisms and potential therapeutic strategies for different diseases in the future.

ADAMTS proteases in vascular biology

ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs) proteases comprise the most recently discovered branch of the extracellular metalloenzymes. Research during the last 15years, uncovered their association with a variety of physiological and pathological processes including blood coagulation, tissue repair, fertility, arthritis and cancer. Importantly, a frequent feature of ADAMTS enzymes relates to their effects on vascular-related phenomena, including angiogenesis. Their specific roles in vascular biology have been clarified by information on their expression profiles and substrate specificity. Through their catalytic activity, ADAMTS proteases modify rather than degrade extracellular proteins. They predominantly target proteoglycans and glycoproteins abundant in the basement membrane, therefore their broad contributions to the vasculature should not come as a surprise. Furthermore, in addition to their proteolytic functions, non-enzymatic roles for ADAMTS have also been identified expanding our understanding on the multiple activities of these enzymes in vascular-related processes.

Association of endothelin-1 and matrix metallopeptidase-9 with metabolic syndrome in middle-aged and older adults

BACKGROUND

Metabolic syndrome (MetS) contains a cluster of cardiovascular risk factors. People with MetS are more susceptible to cardiovascular disease, diabetes mellitus, and cancer. Endothelin-1 (ET-1) and matrix metallopeptidase-9 (MMP-9) have been implicated in the development of cardiovascular diseases, diabetes mellitus and cancers. This cross-sectional study aimed to examine the association of ET-1 and MMP-9 with MetS in middle-aged and older Hong Kong Chinese adults.

METHODS

149 adults aged 50 to 92 (n = 75 for non-MetS group and n = 74 for MetS group) were examined. All subjects were screened for MetS according to the diagnostic guideline of the United States National Cholesterol Education Program (NCEP) Expert Panel Adult Treatment Panel (ATP) III criteria. Serum levels of ET-1 and MMP-9 were measured. Independent t test was used to detect differences between non-MetS and MetS groups and between subjects with or without certain metabolic abnormality. The association of the serum concentration of MMP-9 and ET-1 with MetS parameters were examined by Pearson's correlation analysis.

RESULTS

Serum level of ET-1 is higher in MetS-positive subjects and in subjects with high blood pressure, elevated fasting blood glucose, and central obesity. The serum concentration of MMP-9 is higher in subjects positively diagnosed with MetS and subjects with high blood pressure, elevated fasting blood glucose, low blood high-density lipoprotein-cholesterol (HDL-C), high blood triglycerides, and central obesity. Correlation analyses revealed that serum concentration of ET-1 is positively correlated to systolic blood pressure, waist circumference, fasting blood glucose, and age whereas it is negatively correlated to HDL-C. MMP-9 is positively correlated to systolic blood pressure, waist circumference, fasting blood glucose, and age whereas it is negatively correlated to HDL-C.

CONCLUSION

Serum ET-1 is higher in subjects with hypertension, hyperglycemia, central obesity or MetS. Serum MMP-9 is higher in subjects diagnosed with MetS or having either one of the MetS parameters. Both circulating levels of ET-1 and MMP-9 are correlated to systolic blood pressure, waist circumference, fasting blood glucose, HDL-C, and age. Further research is needed to fully dissect the role of ET-1 and MMP-9 in the development of cancers, diabetes and cardiovascular disease in relation to MetS.

The functional role of platelets in the regulation of angiogenesis

Functionally, platelets are primarily recognized as key regulators of thrombosis and hemostasis. Upon vessel injury, the typically quiescent platelet interacts with subendothelial matrix to regulate platelet adhesion, activation and aggregation, with subsequent induction of the coagulation cascade forming a thrombus. Recently, however, newly described roles for platelets in the regulation of angiogenesis have emerged. Platelets possess an armory of pro- and anti-angiogenic proteins, which are actively sequestered and highly organized in α-granule populations. Platelet activation facilitates their release, eliciting potent angiogenic responses through mechanisms that appear to be tightly regulated. In conjunction, the release of platelet-derived phospholipids and microparticles has also earned merit as synergistic regulators of angiogenesis. Consequently, platelets have been functionally implicated in a range of angiogenesis-dependent processes, including physiological roles in wound healing, vascular development and blood/lymphatic vessel separation, whilst facilitating aberrant angiogenesis in a range of diseases including cancer, atherosclerosis and diabetic retinopathy. Whilst the underlying mechanisms are only starting to be elucidated, significant insights have been established, suggesting that platelets represent a promising therapeutic strategy in diseases requiring angiogenic modulation. Moreover, anti-platelet therapies targeting thrombotic complications also exert protective effects in disorders characterized by persistent angiogenesis.