Identification of the anti-angiogenic site within vascular basement membrane-derived tumstatin

Matrikines in kidney ageing and age-related disease

PURPOSE OF REVIEW

Matrikines are cell-signalling extracellular matrix fragments and they have attracted recent attention from basic and translational scientists, due to their diverse roles in age-related disease and their potential as therapeutic agents. In kidney, the matrix undergoes remodelling by proteolytic fragmentation, so matrikines are likely to play a substantial, yet understudied, role in ageing and pathogenesis of age-related diseases.

RECENT FINDINGS

This review presents an up-to-date description of known matrikines with either a confirmed or highly anticipated role in kidney ageing and disease, including their point of origin, mechanism of cleavage, a summary of known biological actions and the current knowledge which links them to kidney health. We also highlight areas of interest, such as the prospect of matrikine cross-tissue communication, and gaps in knowledge, such as the unexplored signalling potential of many kidney disease-specific matrix fragments.

SUMMARY

We anticipate that knowledge of specific matrikines, and their roles in controlling processes of kidney pathology, could be leveraged for the development of exciting new future therapies through inhibition or even with their supplementation.

Pentastatin, a matrikine of the collagen IVα5, is a novel endogenous mediator of pulmonary endothelial dysfunction

Deposition of basement membrane components, such as collagen IVα5, is associated with altered endothelial cell function in pulmonary hypertension. Collagen IVα5 harbors a functionally active fragment within its C-terminal noncollageneous (NC1) domain, called pentastatin, whose role in pulmonary endothelial cell behavior remains unknown. Here, we demonstrate that pentastatin serves as a mediator of pulmonary endothelial cell dysfunction, contributing to pulmonary hypertension. In vitro, treatment with pentastatin induced transcription of immediate early genes and proinflammatory cytokines and led to a functional loss of endothelial barrier integrity in pulmonary arterial endothelial cells. Mechanistically, pentastatin leads to β1-integrin subunit clustering and Rho/ROCK activation. Blockage of the β1-integrin subunit or the Rho/ROCK pathway partially attenuated the pentastatin-induced endothelial barrier disruption. Although pentastatin reduced the viability of endothelial cells, smooth muscle cell proliferation was induced. These effects on the pulmonary vascular cells were recapitulated ex vivo in the isolated-perfused lung model, where treatment with pentastatin-induced swelling of the endothelium accompanied by occasional endothelial cell apoptosis. This was reflected by increased vascular permeability and elevated pulmonary arterial pressure induced by pentastatin. This study identifies pentastatin as a mediator of endothelial cell dysfunction, which thus might contribute to the pathogenesis of pulmonary vascular disorders such as pulmonary hypertension.NEW & NOTEWORTHY This study is the first to show that pentastatin, the matrikine of the basement membrane (BM) collagen IVα5 polypeptide, triggers rapid pulmonary arterial endothelial cell barrier disruption, activation, and apoptosis in vitro and ex vivo. Mechanistically, pentastatin partially acts through binding to the β1-integrin subunit and the Rho/ROCK pathway. These findings are the first to link pentastatin to pulmonary endothelial dysfunction and, thus, suggest a major role for BM-matrikines in pulmonary vascular diseases such as pulmonary hypertension.

Bacteria-mediated tumor-targeted delivery of tumstatin (54-132) significantly suppresses tumor growth in mouse model by inhibiting angiogenesis and promoting apoptosis

Tumor growth is an angiogenesis-dependent process and accompanied by the formation of hypoxic areas. Tumstatin is a tumor-specific angiogenesis inhibitor that suppresses the proliferation and induces the apoptosis of tumorous vascular endothelial cells. VNP20009, an attenuated Salmonella typhimurium strain, preferentially accumulates in the hypoxic areas of solid tumors. In this study, a novel Salmonella-mediated targeted expression system of tumstatin (VNP-Tum5) was developed under the control of the hypoxia-induced J23100 promoter to obtain anti-tumor efficacy in mice. Treatment with VNP-Tum5 effectively suppressed tumor growth and prolonged survival in the mouse model of B16F10 melanoma. VNP-Tum5 exhibited a higher efficacy in inhibiting the proliferation and inducing the necrosis and apoptosis of B16F10 cells in vitro and in vivo compared with VNP (control). VNP-Tum5 significantly inhibited the proliferation and migration of mouse umbilical vascular endothelial cells to impede angiogenesis. VNP-Tum5 downregulated the expression of anti-vascular endothelial growth factor A, platelet endothelial cell adhesion molecule-1, phosphorylated phosphoinositide 3 kinase, and phosphorylated protein kinase B and upregulated the expression of cleaved-caspase 3 in tumor tissues. This study is the first to use tumstatin-transformed VNP20009 as a tumor-targeted system for treatment of melanoma by combining anti-tumor and anti-angiogenic effects.

The basement membrane in the cross-roads between the lung and kidney

The basement membrane (BM) is a specialized layer of extracellular matrix components that plays a central role in maintaining lung and kidney functions. Although the composition of the BM is usually tissue specific, the lung and the kidney preferentially use similar BM components. Unsurprisingly, diseases with BM defects often have severe pulmonary or renal manifestations, sometimes both. Excessive remodeling of the BM, which is a hallmark of both inflammatory and fibrosing diseases in the lung and the kidney, can lead to the release of BM-derived matrikines, proteolytic fragments with distinct biological functions. These matrikines can then influence disease activity at the site of liberation. However, they are also released to the circulation, where they can directly affect the vascular endothelium or target other organs, leading to extrapulmonary or extrarenal manifestations. In this review, we will summarize the current knowledge of the composition and function of the BM and its matrikines in health and disease, both in the lung and in the kidney. By comparison, we will highlight, why the BM and its matrikines may be central in establishing a renal-pulmonary interaction axis.

Novel Human Placenta-Based Extract for Vascularization Strategies in Tissue Engineering

There is critical unmet need for new vascularized tissues to support or replace injured tissues and organs. Various synthetic and natural materials were already established for use of two-dimensional (2D) and three-dimensional (3D) in vitro neovascularization assays, however, they still cannot mimic the complex functions of the sum of the extracellular matrix (ECM) in native intact tissue. Currently, this issue is only addressed by artificial products such as Matrigel^™, which comprises a complex mixture of ECM proteins, extracted from animal tumor tissue. Despite its outstanding bioactivity, the isolation from tumor tissue hinders its translation into clinical applications. Since nonhuman ECM proteins may cause immune reactions, as are frequently observed in clinical trials, human ECM proteins represent the best option when aiming for clinical applications. Here, we describe an effective method of isolating a human placenta substrate (hpS) that induces the spontaneous formation of an interconnected network of green fluorescence-labeled human umbilical vein endothelial cells (gfpHUVECs) in vitro. The substrate was biochemically characterized by using a combination of bicinchoninic acid (BCA) assay, DNA, and glycosaminoglycan (GAG) content assays, sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE) analysis and Western blot, angiogenesis arrays, chromatographic thrombin detection, high performance liquid chromatography (HPLC)-based amino acid quantification analysis, and assessment of antimicrobial properties. 2D in vitro cell culture experiments have been performed to determine the vasculogenic potential of hpS, which demonstrated that cell networks developed on hpS show a significantly higher degree of complexity (number of tubules/junctions; total/mean tube length) when compared with Matrigel. As 3D cell culture techniques represent a more accurate representation of the in vivo condition, the substrate was 3D solidified using various natural polymers. 3D in vitro vasculogenesis assays have been performed by seeding gfpHUVECs in an hpS-fibrinogen clot. In conclusion, hpS provides a potent human/material-based alternative to xenogenic-material-based biomaterials for vascularization strategies in tissue engineering.

Comparison between sutureless scleral tunnel phacotrabeculectomy with and without placement of anterior capsule remnant

PURPOSE

To compare sutureless scleral tunnel phacotrabeculectomy with and without placement of anterior capsule remnant in the tunnel.

METHODS

In this comparative interventional case series, 41 eyes of 40 patients having open-angle glaucoma (OAG) underwent sutureless scleral tunnel phacotrabeculectomy (Group A) and 28 eyes of 24 patients underwent the same procedure with placement of anterior capsule remnant in the tunnel (Group B). Baseline intraocular pressure (IOP) and IOP at 1 day, 1 month and 6 months after surgery were recorded. IOP < 21 mmHg and 20% reduction in IOP from baseline without and with antiglaucoma medication(s) were considered as complete and qualified success, respectively. Any further procedures or complications that require returning the patient to the operating room or becoming no light perception (NLP) were defined as failure.

RESULTS

Mean preoperative IOP was 26.6 ± 10.08 and 26.64 ± 6.31 mmHg in group A and B, respectively (P-value = 0.984). Mean IOP at 1 month was significantly lower in group B (14.24 ± 4.4 versus. 12.07 ± 3.1, P = 0.027) but at 6 months there was no significant difference between groups (14.38 ± 3.56 versus. 14.8 ± 1.85, P = 0.590). The qualified success rate in group B was higher than group A (78.6 versus. 58.5%) at month 1, while the complete success rate was higher in group A than B (34.1% versus. 17.9%). Neither of any group had complete success at month 6. The qualified success rate was 94.7% and 100% in group A and B, respectively, at 6 months.

CONCLUSION

Placement of anterior capsule remnant in the ostomy during combined phacotrabeculectomy may improve the outcome of the procedure.

Collagen biology making inroads into prognosis and treatment of cancer progression and metastasis

Progression through dissemination to tumor-surrounding tissues and metastasis development is a hallmark of cancer that requires continuous cell-to-cell interactions and tissue remodeling. In fact, metastization can be regarded as a tissue disease orchestrated by cancer cells, leading to neoplastic colonization of new organs. Collagen is a major component of the extracellular matrix (ECM), and increasing evidence suggests that it has an important role in cancer progression and metastasis. Desmoplasia and collagen biomarkers have been associated with relapse and death in cancer patients. Despite the increasing interest in ECM and in the desmoplastic process in tumor microenvironment as prognostic factors and therapeutic targets in cancer, further research is required for a better understanding of these aspects of cancer biology. In this review, published evidence correlating collagen with cancer prognosis is retrieved and analyzed, and the role of collagen and its fragments in cancer pathophysiology is discussed.

[Development of basic research toward clinical application of cleaved fragment of type IV collagen]

Basement membrane is a dense sheet-like extracellular matrix (ECM), which separates cells from surrounding interstitium. Type IV collagen is a major component of basement membrane and three of six α chains (namely α1-α6 chains) form a triple-helix structure. Recently, endogenous bioactive factors called "matricryptins" or "matrikines", which are produced by degrading and cleaving C-terminal domain of type IV collagen, attract attentions as a novel therapeutic target or a candidate for biomarkers. In all type IV collagens, matricryptins called arresten (α1 chain), canstatin (α2), tumstatin (α3), tetrastatin (α4), pentastatin (α5), and hexastatin (α6), have been identified. The type IV collagen-derived matricryptins have been previously studied as new therapeutic targets for neoplastic diseases since they exert anti-angiogenic and/or anti-tumor effects. On the other hand, we have recently demonstrated the cardioprotective effects of matricryptins in addition to the altered expression levels in cardiac diseases. In this review, we introduce the results of fundamental studies for the type IV collagen-derived matricryptins in various diseases, such as neoplastic diseases and cardiac diseases, and discuss the potential clinical application as novel therapeutic agents and biomarkers.

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.

Cryptic collagen elements as signaling hubs in the regulation of tumor growth and metastasis

Structural remodeling of the extracellular matrix is a well-established process associated with tumor growth and metastasis. Tumor and stromal cells that compose the tumor mass function cooperatively to promote the malignant phenotype in part by physically interacting with intact and structurally altered matrix proteins. To this end, collagen represents the most abundant component of the extracellular matrix and is known to control the behavior of histologically distinct tumor types as well as a diversity of stromal cells. Although a significant molecular understanding has been established concerning how cellular interactions with intact collagen govern signaling pathways that control tumor progression, considerably less is known concerning how interactions with cryptic or hidden regions within remodeled collagen may selectively alter signaling cascades, or whether inhibition of these cryptic signaling pathways may represent clinically effective therapeutic strategies. Here, we review the emerging evidence concerning the possible mechanisms for the selective generation of cryptic or hidden elements within collagen and their potential cell surface receptors that may facilitate signal transduction. We discuss the concept that cellular communication links between cell surface receptors and these cryptic collagen elements may serve as functional signaling hubs that coordinate multiple signaling pathways operating within both tumor and stromal cells. Finally, we provide examples to help illustrate the possibility that direct targeting of these unique cryptic signaling hubs may lead to the development of more effective therapeutic strategies to control tumor growth and metastasis.

TargetAntiAngio: A Sequence-Based Tool for the Prediction and Analysis of Anti-Angiogenic Peptides

Cancer remains one of the major causes of death worldwide. Angiogenesis is crucial for the pathogenesis of various human diseases, especially solid tumors. The discovery of anti-angiogenic peptides is a promising therapeutic route for cancer treatment. Thus, reliably identifying anti-angiogenic peptides is extremely important for understanding their biophysical and biochemical properties that serve as the basis for the discovery of new anti-cancer drugs. This study aims to develop an efficient and interpretable computational model called TargetAntiAngio for predicting and characterizing anti-angiogenic peptides. TargetAntiAngio was developed using the random forest classifier in conjunction with various classes of peptide features. It was observed via an independent validation test that TargetAntiAngio can identify anti-angiogenic peptides with an average accuracy of 77.50% on an objective benchmark dataset. Comparisons demonstrated that TargetAntiAngio is superior to other existing methods. In addition, results revealed the following important characteristics of anti-angiogenic peptides: (i) disulfide bond forming Cys residues play an important role for inhibiting blood vessel proliferation; (ii) Cys located at the C-terminal domain can decrease endothelial formatting activity and suppress tumor growth; and (iii) Cyclic disulfide-rich peptides contribute to the inhibition of angiogenesis and cell migration, selectivity and stability. Finally, for the convenience of experimental scientists, the TargetAntiAngio web server was established and made freely available online.

Naja atra venom peptide reduces pain by selectively blocking the voltage-gated sodium channel Nav1.8

The voltage-gated sodium channel Nav1.8 is preferentially expressed in peripheral nociceptive neurons and contributes to inflammatory and neuropathic pain. Therefore, Nav1.8 has emerged as one of the most promising analgesic targets for pain relief. Using large-scale screening of various animal-derived toxins and venoms for Nav1.8 inhibitors, here we identified μ-EPTX-Na1a, a 62-residue three-finger peptide from the venom of the Chinese cobra (Naja atra), as a potent inhibitor of Nav1.8, exhibiting high selectivity over other voltage-gated sodium channel subtypes. Using whole-cell voltage-clamp recordings, we observed that purified μ-EPTX-Na1a blocked the Nav1.8 current. This blockade was associated with a depolarizing shift of activation and repolarizing shift of inactivation, a mechanism distinct from that of any other gating modifier toxin identified to date. In rodent models of inflammatory and neuropathic pain, μ-EPTX-Na1a alleviated nociceptive behaviors more potently than did morphine, indicating that μ-EPTX-Na1a has a potent analgesic effect. μ-EPTX-Na1a displayed no evident cytotoxicity and cardiotoxicity and produced no obvious adverse responses in mice even at a dose 30-fold higher than that producing a significant analgesic effect. Our study establishes μ-EPTX-Na1a as a promising lead for the development of Nav1.8-targeting analgesics to manage pain.

New Insights into the Role of Basement Membrane-Derived Matricryptins in the Heart

The extracellular matrix (ECM), which contributes to structural homeostasis as well as to the regulation of cellular function, is enzymatically cleaved by proteases, such as matrix metalloproteinases and cathepsins, in the normal and diseased heart. During the past two decades, matricryptins have been defined as fragments of ECM with a biologically active cryptic site, namely the 'matricryptic site,' and their biological activities have been initially identified and clarified, including anti-angiogenic and anti-tumor effects. Thus, matricryptins are expected to be novel anti-tumor drugs, and thus widely investigated. Although there are a smaller number of studies on the expression and function of matricryptins in fields other than cancer research, some matricryptins have been recently clarified to have biological functions beyond an anti-angiogenic effect in heart. This review particularly focuses on the expression and function of basement membrane-derived matricryptins, including arresten, canstatin, tumstatin, endostatin and endorepellin, during cardiac diseases leading to heart failure such as cardiac hypertrophy and myocardial infarction.

Contribution of Tumor Endothelial Cells in Cancer Progression

Tumor progression depends on the process of angiogenesis, which is the formation of new blood vessels. These newly formed blood vessels supply oxygen and nutrients to the tumor, supporting its progression and providing a gateway for tumor metastasis. Tumor angiogenesis is regulated by the balance between angiogenic activators and inhibitors within the tumor microenvironment. Because the newly formed tumor blood vessels originate from preexisting normal vessels, tumor blood vessels, and tumor endothelial cells (TECs) have historically been considered to be the same as normal blood vessels and endothelial cells; however, evidence of TECs’ distinctive abnormal phenotypes has increased. In addition, it has been revealed that TECs constitute a heterogeneous population. Thus, TECs that line tumor blood vessels are important targets in cancer therapy. We have previously reported that TECs induce cancer metastasis. In this review, we describe recent studies on TEC abnormalities related to cancer progression to provide insight into new anticancer therapies.

Escherichia coli Nissle 1917 engineered to express Tum-5 can restrain murine melanoma growth

Tumor growth and metastasis depend on angiogenesis. Thus, inhibiting tumor angiogenesis has become promising cancer therapeutic strategy in recent years. Tumstatin is a more powerful angiogenesis inhibitor than endostatin. Anti-angiogenic active fragment encoding amino acids 45–132 (Tum-5) of tumstatin was subcloned into four different inducible expression vectors and successfully solubly expressed in Escherichia coli BL21 (DE3) in this study. Subsequently, an anaerobic inducible expression vector was constructed under Vitreoscilla hemoglobin gene promoter Pvhb in E. coli Nissle 1917 (EcN). The secretory expression of Tum-5 in the engineered bacterium was determined in vitro and in vivo by Western blot or immunochemistry. The anti-tumor effect detection demonstrated that EcN could specifically colonize the tumor, and B16 melanoma tumor growth was remarkably restrained by EcN (Tum-5) in mice bearing B16 melanoma tumor. Abundant infiltrating inflammatory cells were observed in tumor areas of the EcN-treated group through hematoxylin and eosin staining, with a relatively reduced expression of endothelial marker platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) by immunofluorescence in tumor sections of EcN (Tum-5)-treated mice. No significant morphological differences were observed in the liver, kidney and spleen between EcN-treated mice and the control group, indicating that EcN was cleared by the immune system and did not cause systemic toxicity in mice. These findings demonstrated that the gene delivery of Tum-5 to solid tumors could be an effective strategy for cancer therapy.

Regulation of spermatogenesis by a local functional axis in the testis: role of the basement membrane-derived noncollagenous 1 domain peptide

Spermatogenesis takes place in the epithelium of the seminiferous tubules of the testes, producing millions of spermatozoa per day in an adult male in rodents and humans. Thus, multiple cellular events that are regulated by an array of signaling molecules and pathways are tightly coordinated to support spermatogenesis. Here, we report findings of a local regulatory axis between the basement membrane (BM), the blood-testis barrier (BTB), and the apical ectoplasmic specialization (apical ES; a testis-specific, actin-rich adherens junction at the Sertoli cell-spermatid interface) to coordinate cellular events across the seminiferous epithelium during the epithelial cycle. In short, a biologically active fragment, noncollagenous 1 (NC1) domain that is derived from collagen chains in the BM, was found to modulate cell junction dynamics at the BTB and apical ES. NC1 domain from the collagen α3(IV) chain was cloned into a mammalian expression vector, pCI-neo, with and without a collagen signal peptide. We also prepared a specific Ab against the purified recombinant NC1 domain peptide. These reagents were used to examine whether overexpression of NC1 domain with high transfection efficacy would perturb spermatogenesis, in particular, spermatid adhesion (i.e., inducing apical ES degeneration) and BTB function (i.e., basal ES and tight junction disruption, making the barrier leaky), in the testis in vivo We report our findings that NC1 domain derived from collagen α3(IV) chain-a major structural component of the BM-was capable of inducing BTB remodeling, making the BTB leaky in studies in vivo Furthermore, NC1 domain peptide was transported across the epithelium via a microtubule-dependent mechanism and is capable of inducing apical ES degeneration, which leads to germ cell exfoliation from the seminiferous epithelium. Of more importance, we show that NC1 domain peptide exerted its regulatory effect by disorganizing actin microfilaments and microtubules in Sertoli cells so that they failed to support cell adhesion and transport of germ cells and organelles (e.g., residual bodies, phagosomes) across the seminiferous epithelium. This local regulatory axis between the BM, BTB, and the apical ES thus coordinates cellular events that take place across the seminiferous epithelium during the epithelial cycle of spermatogenesis.-Chen, H., Mruk, D. D., Lee, W. M., Cheng, C. Y. Regulation of spermatogenesis by a local functional axis in the testis: role of the basement membrane-derived noncollagenous 1 domain peptide.

Vector-mediated Tum-5 expression in neovascular endothelial cells for treating hepatocellular carcinoma

Hypervascular hepatocellular carcinoma (HCC) is one of the leading causes of cancer-associated mortality. Angiogenesis is an important contributor to HCC progression and metastasis; therefore, inhibiting angiogenesis may be an effective method of treating HCC. Tumstatin is a novel type of efficient endogenous vascular endothelial cell growth inhibiting factor. The anti-angiogenic activity of tumstatin is localized to the 54-132 amino acid region (Tum-5). In a previous study performed by our group, the gene fragment encoding Tum-5 was cloned and inserted into a pLXSN retroviral vector. In the present study, the anti-angiogenic effects of Tum-5 and the antitumor effects exerted by the pLXSN-Tum-5 vector in vivo were investigated. The results demonstrated that pLXSN-Tum-5 significantly inhibited the growth of human umbilical vein endothelial cells compared with pLXSN, but had no obvious effect on HepG2 cell growth. Moreover, the antitumor and anti-angiogenic activity of Tum-5 was examined in vivo using a xenograft of H22 HCC cells. The results indicated that pLXSN-Tum-5 significantly inhibited tumor growth following 5 injections over 10 days. The size and weight of tumors in the pLXSN-Tum-5 group were lower than those in the saline and pLXSN groups. Furthermore, immunohistochemical analysis with CD31 antibodies indicated that the average microvessel density in the pLXSN-Tum-5 group were significantly lower than that in the saline and pLXSN groups. These results suggested that Tum-5 exerts its antitumor activity by suppressing vascular endothelial cells. The gene fragment of Tum-5 may be developed as an effective inhibitor of angiogenesis and used to treat patients with HCC.

A Comprehensive View of the Structural and Functional Alterations of Extracellular Matrix by Snake Venom Metalloproteinases (SVMPs): Novel Perspectives on the Pathophysiology of Envenoming

Snake venom metalloproteinases (SVMPs) affect the extracellular matrix (ECM) in multiple and complex ways. Previously, the combination of various methodological platforms, including electron microscopy, histochemistry, immunohistochemistry, and Western blot, has allowed a partial understanding of such complex pathology. In recent years, the proteomics analysis of exudates collected in the vicinity of tissues affected by SVMPs has provided novel and exciting information on SVMP-induced ECM alterations. The presence of fragments of an array of ECM proteins, including those of the basement membrane, has revealed a complex pathological scenario caused by the direct action of SVMPs. In addition, the time-course analysis of these changes has underscored that degradation of some fibrillar collagens is likely to depend on the action of endogenous proteinases, such as matrix metalloproteinases (MMPs), synthesized as a consequence of the inflammatory process. The action of SVMPs on the ECM also results in the release of ECM-derived biologically-active peptides that exert diverse actions in the tissue, some of which might be associated with reparative events or with further tissue damage. The study of the effects of SVMP on the ECM is an open field of research which may bring a renewed understanding of snake venom-induced pathology.

Matrix metalloproteinase 14 modulates signal transduction and angiogenesis in the cornea

The cornea is transparent and avascular, and retention of these characteristics is critical to maintaining vision clarity. Under normal conditions, wound healing in response to corneal injury occurs without the formation of new blood vessels; however, neovascularization may be induced during corneal wound healing when the balance between proangiogenic and antiangiogenic mediators is disrupted to favor angiogenesis. Matrix metalloproteinases (MMPs), which are key factors in extracellular matrix remodeling and angiogenesis, contribute to the maintenance of this balance, and in pathologic instances, can contribute to its disruption. Here, we elaborate on the facilitative role of MMPs, specifically MMP-14, in corneal neovascularization. MMP-14 is a transmembrane MMP that is critically involved in extracellular matrix proteolysis, exosome transport, and cellular migration and invasion, processes that are critical for angiogenesis. To aid in developing efficacious therapies that promote healing without neovascularization, it is important to understand and further investigate the complex pathways related to MMP-14 signaling, which can also involve vascular endothelial growth factor, basic fibroblast growth factor, Wnt/β-catenin, transforming growth factor, platelet-derived growth factor, hepatocyte growth factor or chemokines, epidermal growth factor, prostaglandin E2, thrombin, integrins, Notch, Toll-like receptors, PI3k/Akt, Src, RhoA/RhoA kinase, and extracellular signal-related kinase. The involvement and potential contribution of these signaling molecules or proteins in neovascularization are the focus of the present review.

S R, Venkatesan S. AntiAngioPred: A Server for Prediction of Anti-Angiogenic Peptides

The process of angiogenesis is a vital step towards the formation of malignant tumors. Anti-angiogenic peptides are therefore promising candidates in the treatment of cancer. In this study, we have collected anti-angiogenic peptides from the literature and analyzed the residue preference in these peptides. Residues like Cys, Pro, Ser, Arg, Trp, Thr and Gly are preferred while Ala, Asp, Ile, Leu, Val and Phe are not preferred in these peptides. There is a positional preference of Ser, Pro, Trp and Cys in the N terminal region and Cys, Gly and Arg in the C terminal region of anti-angiogenic peptides. Motif analysis suggests the motifs "CG-G", "TC", "SC", "SP-S", etc., which are highly prominent in anti-angiogenic peptides. Based on the primary analysis, we developed prediction models using different machine learning based methods. The maximum accuracy and MCC for amino acid composition based model is 80.9% and 0.62 respectively. The performance of the models on independent dataset is also reasonable. Based on the above study, we have developed a user-friendly web server named "AntiAngioPred" for the prediction of anti-angiogenic peptides. AntiAngioPred web server is freely accessible at http://clri.res.in/subramanian/tools/antiangiopred/index.html (mirror site: http://crdd.osdd.net/raghava/antiangiopred/).

KLF4 Promotes Angiogenesis by Activating VEGF Signaling in Human Retinal Microvascular Endothelial Cells

The transcription factor Krüppel-like factor 4 (KLF4) has been implicated in regulating cell proliferation, migration and differentiation in a variety of human cells and is one of four factors required for the induction of pluripotent stem cell reprogramming. However, its role has not been addressed in ocular neovascular diseases. This study investigated the role of KLF4 in angiogenesis and underlying molecular mechanisms in human retinal microvascular endothelial cells (HRMECs). The functional role of KLF4 in HRMECs was determined following lentiviral vector mediated inducible expression and shRNA knockdown of KLF4. Inducible expression of KLF4 promotes cell proliferation, migration and tube formation. In contrast, silencing KLF4 inhibits cell proliferation, migration, tube formation and induces apoptosis in HRMECs. KLF4 promotes angiogenesis by transcriptionally activating VEGF expression, thus activating the VEGF signaling pathway in HRMECs.

Tumstatin induces apoptosis mediated by Fas signaling pathway in oral squamous cell carcinoma SCC-VII cells

Oral squamous cell carcinoma is a cancer originating in the tissues lining the mouth and lips. The present study investigated the effects of recombinant tumstatin, an anti-angiogenic agent with distinct antitumor activity, on oral squamous cell carcinoma SCC-VII cells. Apoptosis was characterized by YO-PRO-1 staining, sub-G1 population, and DNA fragmentation analysis. Apoptotic mechanism of tumstatin was also investigated. The antitumor activity of tumstatin was further evaluated using an SCC-VII animal model. Recombinant tumstatin was found to decrease the viability of SCC-VII cells in a dose-dependent manner. The number of cells stained with the apoptotic marker YO-PRO-1, the sub-G1 cell population and the level of apoptotic DNA fragmentation increased in the SCC-VII cells following treatment with recombinant tumstatin. In addition, recombinant tumstatin treatment increased the expression of the Fas gene at the transcript and protein levels, and the inhibition of cell viability by recombinant tumstatin was suppressed by a neutralizing anti-Fas antibody. Furthermore, treatment with recombinant tumstatin decreased the volume and weight of tumors in C3H/HeJ mice implanted with SCC-VII cells. In conclusion, the results indicated that tumstatin induced apoptosis that is mediated by the Fas signaling pathway in SCC-VII cells and inhibited tumor growth in an SCC-VII animal model.

Inhibition of angiogenesis by a synthetic fusion protein VTF derived from vasostatin and tumstatin

The inhibition of angiogenesis represents a potential strategy for antitumor therapy. A novel synthetic fusion protein VTF, composed of bioactive fragments from two different angiogenesis inhibitors, vasostatin and tumstatin with a (Gly-Ser-Gly)2 bridge, was generated using the pET-15b expression vector. The fusion protein VTF showed significantly enhanced efficacy in inhibiting human endothelial cell proliferation and tube formation and neovascularization on chick embryo chorioallantoic membrane. Moreover, VTF suppressed the growth of B16 melanoma and the formation of tumor blood vessels potently in vivo. These results indicated that the fusion protein containing the bioactive fragments of multiple angiogenesis inhibitors might be a promising therapeutic agent for tumor treatment.

Corneal angiogenesis modulation by cysteine cathepsins: In vitro and in vivo studies

Corneal avascularization is essential for normal vision. Several antiangiogenic factors were identified in cornea such as endostatin and angiostatin. Cathepsin V, which is highly expressed in the cornea, can hydrolyze human plasminogen to release angiostatin fragments. Herein, we describe a detailed investigation of the expression profile of cathepsins B, L, S and V in the human cornea and the role of cysteine peptidases in modulating angiogenesis both in vitro and in vivo. We used various methodological tools for this purpose, including real-time PCR, SDS-PAGE, western blotting, catalytic activity assays, cellular assays and induction of corneal neovascularity in rabbit eyes. Human corneal enzymatic activity assays revealed the presence of cysteine proteases that were capable of processing endogenous corneal plasminogen to produce angiostatin-like fragments. Comparative real-time analysis of cathepsin B, L, S and V expression revealed that cathepsin V was the most highly expressed, followed by cathepsins L, B and S. However, cathepsin V depletion revealed that this enzyme is not the major cysteine protease responsible for plasminogen degradation under non-pathological conditions. Furthermore, western blotting analysis indicated that only cathepsins B and S were present in their enzymatically active forms. In vivo analysis of angiogenesis demonstrated that treatment with the cysteine peptidase inhibitor E64 caused a reduction in neovascularization. Taken together, our results show that human corneal cysteine proteases are critically involved in angiogenesis.

Antitumor activity of adenoviral vector containing T42 and 4xT42 peptide gene through inducing apoptosis of tumor cells and suppressing angiogenesis

The T42 peptide, generated from two active fragments of tumstatin, has been shown to have anti‑tumor activity. The adenoviral vector is the most frequently used vector in research and clinical trials for gene therapy. In the present study, the anti‑tumor activity of the T42 peptide and quadruple T42 (4xT42) peptide adenoviral vectors were elucidated for the first time, to the best of our knowledge. Human embryonic kidney 293 cells were infected with plasmid adenovirus (pAd)‑enhanced green fluorescent protein (EGFP)‑T42 or pAd‑EGFP‑4xT42 and the expression of the T42 and 4xT42 genes was confirmed by the identification of GFP expression and reverse transcription polymerase chain reaction experiments. The anti‑cancer effects of pAd‑EGFP‑T42 and pAd‑EGFP‑4xT42 on breast cancer cells in vivo and in vitro were subsequently investigated. The results indicated that the packaging of the recombinant adenoviruses with the viral titer was successful, following purification at 5x109 plaque forming units/ml. The results also revealed that the recombinant adenoviruses promoted apoptosis in MCF‑7 breast cancer cells and inhibited cancer growth. Through the analysis of caspase‑3, B‑cell lymphoma 2 (Bcl‑2) and Bcl‑2‑associated X protein expression, it was demonstrated that the T42/4xT42 peptide may induce apoptosis via the mitochondrial pathway. In addition, mouse xenograft experiments confirmed that the T42 peptide inhibited tumor growth and reduced angiogenesis in vivo. In conclusion, the results of the present study indicated that the T42 and 4xT42 peptide genes, transfected by a recombinant adenovirus, may provide a potential novel strategy for the treatment of breast cancer.

Extracellular matrix modulates angiogenesis in physiological and pathological conditions

Angiogenesis is a multistep process driven by a wide range of positive and negative regulatory factors. Extracellular matrix (ECM) plays a crucial role in the regulation of this process. The degradation of ECM, occurring in response to an angiogenic stimulus, leads to degradation or partial modification of matrix molecules, release of soluble factors, and exposure of cryptic sites with pro- and/or antiangiogenic activity. ECM molecules and fragments, resulting from proteolysis, can also act directly as inflammatory stimuli, and this can explain the exacerbated angiogenesis that drives and maintains several inflammatory diseases. In this review we have summarized some of the more recent literature data concerning the molecular control of ECM in angiogenesis in both physiological and pathological conditions.

Overexpression of tumstatin in genetically modified megakaryocytes changes the proangiogenic effect of platelets

BACKGROUND

Thrombocytopenia is a common side effect of tumor chemotherapy, the main management approach to which is based on platelet (PLT) transfusion. However, PLTs, containing angiogenesis regulators, play a major role in boosting tumor growth and metastasis. The purpose of the study was to determine whether PLTs have the capacity to overexpress tumstatin by modified megakaryocyte (MK) and PLT precursors using lentivirus-mediated gene transfer, which might lead to alteration in proangiogenic effect of PLTs.

STUDY DESIGN AND METHODS

CD34+ hematopoietic stem cells (HSCs) were transduced with recombinant lentivirus carrying tumstatin and induced to produce MKs and PLTs in the culture medium containing a cytokine cocktail. Flow cytometry and aggregation test were used to detect the generation and function of MKs and PLTs. Western blot analysis and confocal microscopy were applied to examine the expression and distribution of tumstatin in transgenic MKs and PLTs. Capillary tube formation of human umbilical vein endothelial cells (HUVECs) was used to evaluate the inhibitory effect of transgenic PLTs.

RESULTS

CD34+ HSCs can be efficiently transduced with lentivirus vectors and successfully differentiated into MKs and PLTs. Large amounts of functional MKs and PLTs could be generated and had correct biologic characteristics. The tests demonstrated the feasibility of tumstatin expression in MKs and PLTs under control of the cytomegalovirus promoter, that thus tumstatin was stored in the α-granules of PLTs, and that the releasate of thrombin or A543 cell-stimulated transgenic PLTs obviously inhibited the growth of capillary tube network structures of HUVECs.

CONCLUSION

Gene-modified CD34+ HSCs not only successfully differentiated into MKs and PLTs but also expressed tumstatin protein. Release of tumstatin in transgenic PLT granules led to antiangiogenic effect of PLTs.

Lamstatin--a novel inhibitor of lymphangiogenesis derived from collagen IV

The lymphatic system is essential for the maintenance of tissue homeostasis and immunity. Its dysfunction in disease (such as lymphangioleiomyomatosis) can lead to chylous effusions, oedema or dissemination of malignant cells. Collagen IV has six α chains, of which some of the non-collagenous-1 domains have endogenous anti-angiogenic properties, however, little is known about specific endogenous anti-lymphangiogenic characteristics. In this study we sought to investigate the expression levels of collagen IV non-collagenous-1 domains in lung tissue of patients with and without lymphangioleiomyomatosis to explore the hypothesis that a member of the collagen IV family, specifically the non-collagenous domain-1 of α5, which we named lamstatin, has anti-lymphangiogenic properties. Levels of lamstatin detected by immunohistochemistry were decreased in lungs of lymphangioleiomyomatosis patients. We produced recombinant lamstatin in an E.coli expression system and synthesized a 17-amino acid peptide from a theoretically identified, active region (CP17) and tested their effects in vitro and in vivo. Recombinant lamstatin and CP17 inhibited proliferation, migration and cord formation of human microvascular lung lymphatic endothelial cells, in vitro. Furthermore, lamstatin and CP17 decreased complexity and dysplasia of the tumour-associated lymphatic network in a lung adenocarcinoma xenograft mouse model. In this study we identified a novel, direct inhibitor of lymphangiogenesis, derived from collagen IV. This may prove useful for exploring new avenues of treatment for lymphangioleiomyomatosis and metastasis via the lymphatic system in general.

LF-15 & T7, synthetic peptides derived from tumstatin, attenuate aspects of airway remodelling in a murine model of chronic OVA-induced allergic airway disease

Background

Tumstatin is a segment of the collagen-IV protein that is markedly reduced in the airways of asthmatics. Tumstatin can play an important role in the development of airway remodelling associated with asthma due to its anti-angiogenic properties. This study assessed the anti-angiogenic properties of smaller peptides derived from tumstatin, which contain the interface tumstatin uses to interact with the αVβ3 integrin.

Methods

Primary human lung endothelial cells were exposed to the LF-15, T3 and T7 tumstatin-derived peptides and assessed for cell viability and tube formation in vitro. The impact of the anti-angiogenic properties on airways hyperresponsiveness (AHR) was then examined using a murine model of chronic OVA-induced allergic airways disease.

Results

The LF-15 and T7 peptides significantly reduced endothelial cell viability and attenuated tube formation in vitro. Mice exposed to OVA+ LF-15 or OVA+T7 also had reduced total lung vascularity and AHR was attenuated compared to mice exposed to OVA alone. T3 peptides reduced cell viability but had no effect on any other parameters.

Conclusion

The LF-15 and T7 peptides may be appropriate candidates for use as novel pharmacotherapies due to their small size and anti-angiogenic properties observed in vitro and in vivo.

Connective tissue growth factor (CTGF) expression modulates response to high glucose

Connective tissue growth factor (CTGF) is an important mediator of fibrosis; emerging evidence link changes in plasma and urinary CTGF levels to diabetic kidney disease. To further ascertain the role of CTGF in responses to high glucose, we assessed the consequence of 4 months of streptozotocin-induced diabetes in wild type (+/+) and CTGF heterozygous (+/−) mice. Subsequently, we studied the influence of glucose on gene expression and protein in mice embryonic fibroblasts (MEF) cells derived from wildtype and heterozygous mice. At study initiation, plasma glucose, creatinine, triglyceride and cholesterol levels were similar between non-diabetic CTGF+/+ and CTGF+/− mice. In the diabetic state, plasma glucose levels were increased in CTGF+/+ and CTGF+/− mice (28.2 3.3 mmol/L vs 27.0 3.1 mmol/L), plasma triglyceride levels were lower in CTGF+/− mice than in CTGF+/+ (0.7 0.2 mmol/L vs 0.5 0.1 mmol/L, p<0.05), but cholesterol was essentially unchanged in both groups. Plasma creatinine was higher in diabetic CTGF+/+ group (11.7±1.2 vs 7.9±0.6 µmol/L p<0.01), while urinary albumin excretion and mesangial expansion were reduced in diabetic CTGF+/− animals. Cortices from diabetic mice (both CTGF +/+ and CTGF +/−) manifested higher expression of CTGF and thrombospondin 1 (TSP1). Expression of nephrin was reduced in CTGF +/+ animals; this reduction was attenuated in CTGF+/− group. In cultured MEF from CTGF+/+ mice, glucose (25 mM) increased expression of pro-collagens 1, IV and XVIII as well as fibronectin and thrombospondin 1 (TSP1). In contrast, activation of these genes by high glucose was attenuated in CTGF+/− MEF. We conclude that induction of Ctgf mediates expression of extracellular matrix proteins in diabetic kidney. Thus, genetic variability in CTGF expression directly modulates the severity of diabetic nephropathy.

Angiogenesis and collagen type IV expression in different endothelial cell culture systems

In vitro angiogenesis assays constitute an important tool for studying the mechanisms of angiogenesis and for identification of pro- and anti-angiogenic substances. Therefore, endothelial cell and media systems used for in vitro angiogenesis assays are required to mimic the angiogenic process in vivo including endothelial capability to express collagen type IV as a component of the basement membrane. In this study, the expression of collagen type IV and its α chains (α1-6) was investigated in different endothelial cell culture systems in vitro qualitatively and quantitatively. These systems included four different batches of microvascular endothelial cells derived from the human skin, heart and lung, from which only two batches were found to be angiogenic and two batches were classified as non-angiogenic. Distribution of the transcripts of the α chains of collagen type IV was similar in all cell and media systems investigated. However, secretion and deposition of a stable extracellular network of collagen type IV could only be observed in the angiogenic cultures. In conclusion, the consecutive steps of the angiogenic cascade in vivo as well as in vitro depend on an increasing secretion and subsequent extracellular deposition of collagen type IV.

A new anti-tumor strategy based on in vivo tumstatin overexpression after plasmid electrotransfer in muscle

The NC1 domains from the different α(IV) collagen chains were found to exert anti-tumorigenic and/or anti-angiogenic activities. A limitation to the therapeutic use of these matrikines is the large amount of purified recombinant proteins, in the milligram range in mice that should be administered daily throughout the experimental procedures. In the current study, we developed a new therapeutic approach based on tumstatin (NC1α3(IV)) overexpression in vivo in a mouse melanoma model. Gene electrotransfer of naked plasmid DNA (pDNA) is particularly attractive because of its simplicity, its lack of immune responsiveness and its safety. The pDNA electrotransfer in muscle mediates a substantial gene expression that lasts several months. A pVAX1© vector containing the tumstatin cDNA was injected into the legs of C57BL/6 mice and submitted to electrotranfer. Sera were collected at different times and tumstatin was quantified by ELISA. Tumstatin secretion reached a plateau at day 21 with an expression level of 12 μg/mL. For testing the effects of tumstatin expression on tumor growth in vivo, B16F1 melanoma cells were subcutaneously injected in mice 7 days after empty pVAX1© (Mock) or pVAX1©-tumstatin electrotransfer. Tumstatin expression triggered a large decrease in tumor growth and an increase in mouse survival. This new therapeutic approach seems promising to inhibit tumor progression in vivo.

Fluctuating roles of matrix metalloproteinase-9 in oral squamous cell carcinoma

One hallmark of cancer is the degradation of the extracellular matrix (ECM), which is caused by proteinases. In oral cancers, matrix metalloproteinases (MMPs), especially MMP-9, are associated with this degradation. MMPs break down the ECM allowing cancer to spread; they also release various factors from their cryptic sites, including cytokines. These factors modulate cell behavior and enhance cancer progression by regulating angiogenesis, migration, proliferation, and invasion. The development of early metastases is typical for oral cancer, and increased MMP-9 expression is associated with a poor disease prognosis. However, many studies fail to relate MMP-9 expression with metastasis formation. Contrary to earlier models, recent studies show that MMP-9 plays a protective role in oral cancers. Therefore, the role of MMP-9 is complicated and may fluctuate throughout the different types and stages of oral cancers.

Biomimetic hydrogels for controlled biomolecule delivery to augment bone regeneration

The regeneration of large bone defects caused by trauma or disease remains a significant clinical problem. Although osteoinductive growth factors such as bone morphogenetic proteins have entered clinics, transplantation of autologous bone remains the gold standard to treat bone defects. The effective treatment of bone defects by protein therapeutics in humans requires quantities that exceed the physiological doses by several orders of magnitude. This not only results in very high treatment costs but also bears considerable risks for adverse side effects. These issues have motivated the development of biomaterials technologies allowing to better control biomolecule delivery from the solid phase. Here we review recent approaches to immobilize biomolecules by affinity binding or by covalent grafting to biomaterial matrices. We focus on biomaterials concepts that are inspired by extracellular matrix (ECM) biology and in particular the dynamic interaction of growth factors with the ECM. We highlight the value of synthetic, ECM-mimicking matrices for future technologies to study bone biology and develop the next generation of 'smart' implants.

Synthetic disulfide-bridged cyclic peptides mimic the anti-angiogenic actions of chondromodulin-I

Chondromodulin-I (ChM-I) is a 25-kDa glycoprotein in cartilage matrix that inhibits angiogenesis. It contains two distinctive structural domains: the N-terminal third of the molecule is a hydrophilic domain that contains O-linked and N-linked oligosaccharide chains, and the C-terminal two-thirds is a hydrophobic domain that contains all of the cysteine residues. In the present study, we have attempted to further uncover the structural requirements for ChM-I to exert anti-angiogenic activity by monitoring its inhibition of the vascular endothelial growth factor (VEGF)-A-induced migration of HUVEC in vitro. Site-directed mutagenesis experiments revealed that the cyclic structure formed by the disulfide bridge between Cys⁸³ and Cys⁹⁹ in human ChM-I is indispensable for its anti-angiogenic function. Moreover, the C-terminal hydrophobic tail (from Trp¹¹¹ to Val¹²⁰) was found to play an important role in ensuring the effectiveness of ChM-I activity on HUVEC. A synthetic cyclic peptide corresponding to the ChM-I region between Ile⁸² to Arg¹⁰⁰ also inhibited the migration of HUVEC, while replacing the Cys⁸³ and Cys⁹⁹ residues in this peptide with Ser completely negated this inhibitory activity. An additional synthetic cyclic peptide harboring the hydrophobic C-terminal tail of ChM-I clearly mimicked the inhibitory action of this protein on the migration of HUVEC and successfully inhibited tumor angiogenesis and growth in a xenograft mouse model of human chondrosarcoma.

Tetrastatin, the NC1 domain of the α4(IV) collagen chain: a novel potent anti-tumor matrikine

BACKGROUND

NC1 domains from α1, α2, α3 and α6(IV) collagen chains were shown to exert anti-tumor or anti-angiogenic activities, whereas the NC1 domain of the α4(IV) chain did not show such activities so far.

METHODOLOGY/PRINCIPAL FINDINGS

We demonstrate in the present paper that the NC1 α4(IV) domain exerts a potent anti-tumor activity both in vitro and in an experimental human melanoma model in vivo. The overexpression of NC1 α4(IV) in human UACC-903 melanoma cells strongly inhibited their in vitro proliferative (-38%) and invasive (-52%) properties. MT1-MMP activation was largely decreased and its cellular distribution was modified, resulting in a loss of expression at the migration front associated with a loss of migratory phenotype. In an in vivo xenograft model in athymic nude mice, the subcutaneous injection of NC1 α4(IV)-overexpressing melanoma cells induced significantly smaller tumors (-80% tumor volume) than the Mock cells, due to a strong inhibition of tumor growth. Exogenously added recombinant human NC1 α4(IV) reproduced the inhibitory effects of NC1 α4(IV) overexpression in UACC-903 cells but not in dermal fibroblasts. An anti-αvβ3 integrin blocking antibody inhibited cell adhesion on recombinant human NC1 α4(IV) substratum. The involvement of αvβ3 integrin in mediating NC1 α4(IV) effect was confirmed by surface plasmon resonance (SPR) binding assays showing that recombinant human NC1 α4(IV) binds to αvβ3 integrin (K(D) = 148 ± 9.54 nM).

CONCLUSION/SIGNIFICANCE

Collectively, our results demonstrate that the NC1 α4(IV) domain, named tetrastatin, is a new endogenous anti-tumor matrikine.

Mesenchymal stem cells modified to express lentivirus TNF-α Tumstatin(45-132) inhibit the growth of prostate cancer

Mesenchymal stem cells (MSCs) are a potential novel delivery system for cell-based gene therapies. Although tumour necrosis factor (TNF)-α has been shown to have antitumour activity, its use in therapy is limited by its systemic toxicity. For the present study, we designed lentivirus-mediated signal peptide TNF-α-Tumstatin(45-132) -expressing mesenchymal stem cells (SPTT-MSCs) as a novel anti-cancer approach. We evaluated the effects of this approach on human prostate cancer cells (PC3 and LNCaP) by co-culturing them with either SPTT-MSCs or supernatants from their culture medium in vitro. The antitumour effects and possible mechanisms of action of SPTT-MSCs were then determined in PC3 cells in vivo. The results showed that efficient TNF-α-Tumstatin(45-132) -expressing MSCs had been established, and demonstrated that SPTT-MSCs inhibited the proliferation of and induced apoptosis in prostate cancer cells and xenograft tumours. As would be expected, given the properties of the individual proteins, the TNF-α-Tumstatin(45-132) fusion exerted potent cytotoxic effects on human prostate cancer cells and tumours via the death receptor-dependent apoptotic pathway and via antiangiogenic effects. Our findings suggest that SPTT-MSCs have significant activity against prostate cancer cells, and that they may represent a promising new therapy for prostate cancer.

Matrikines and the lungs

The extracellular matrix is a complex network of fibrous and nonfibrous molecules that not only provide structure to the lung but also interact with and regulate the behaviour of the cells which it surrounds. Recently it has been recognised that components of the extracellular matrix proteins are released, often through the action of endogenous proteases, and these fragments are termed matrikines. Matrikines have biological activities, independent of their role within the extracellular matrix structure, which may play important roles in the lung in health and disease pathology. Integrins are the primary cell surface receptors, characterised to date, which are used by the matrikines to exert their effects on cells. However, evidence is emerging for the need for co-factors and other receptors for the matrikines to exert their effects on cells. The potential for matrikines, and peptides derived from these extracellular matrix protein fragments, as therapeutic agents has recently been recognised. The natural role of these matrikines (including inhibitors of angiogenesis and possibly inflammation) make them ideal targets to mimic as therapies. A number of these peptides have been taken forward into clinical trials. The focus of this review will be to summarise our current understanding of the role, and potential for highly relevant actions, of matrikines in lung health and disease.

Characterization of Type I and IV Collagens by Raman Microspectroscopy: Identification of Spectral Markers of the Dermo-Epidermal Junction

Type I and IV collagens are important constituents of the skin. Type I collagen is found in all dermal layers in high proportion, while type IV collagen is localized in the basement membrane of the dermo-epidermal junction (DEJ). These proteins are strongly altered during aging or cancer progression. Although they possess amino acid compositions which, are close, they present also important structural differences inducing specific physicochemical properties. Raman spectroscopy is based on a nondestructive interaction of the light with the matter. This technique permits to probe the intrinsic molecular composition of the samples without staining or particular preparation. The aim of our research is to study the correlation between the molecular conformations of type I and IV collagens and their Raman features. We showed that signals specific of each protein can be revealed and that they translate structural differences between the two collagens. From this collagens spectral characterization, the analysis of skin sections also permitted to identify spectral markers of dermis, epidermis, and epidermis/dermis interface. These preliminary results represent basic data for further studies, particularly to probe skin molecular alterations induced by chronologic aging.

Matrix revolution: molecular mechanism for inflammatory corneal neovascularization and restoration of corneal avascularity by epithelial stem cell transplantation

Corneal neovascularization (CNV) associated with severe limbal stem cell (LSC) deficiency remains a challenging ocular surface disease in that corneal inflammation may persist and progress, and the condition will not improve without LSC transplantation. A prominent feature after successful LSC transplantation is the suppression of corneal inflammation and CNV, which is generally attributed to the endogenous anti-angiogenic/anti-inflammatory factors secreted by corneal epithelial cells. In addition, corneal epithelial basement membrane (EBM) plays a unique role in the regulation of angiogenesis; several potent anti-angiogenic factors are derived from the matrix component of EBM, such as endostatin (from collagen XVIII) and restin (from collagen XV). Also, angio-inhibitory thrombospondin and tissue inhibitor of metalloproteinase-3 are deposited in EBM. Moreover, the heparan sulphate proteoglycan in EBM can bind and sequester VEGF and FGF-2 from activation. Recently, cultivated corneal epithelial transplantation (CCET) and cultivated oral mucosal epithelial transplantation (COMET) have emerged as promising techniques for the treatment of LSC deficiency. When human limbo-corneal epithelial (HLE) cells are cultivated on cryopreserved amniotic membrane, production of endostatin, restin, and IL-1ra is enhanced. This highlights the significance of delicate epithelial-matrix interactions in the generation of anti-angiogenic/anti-inflammatory factors by HLE cells, and this may, in part, explain the rapid restoration of corneal avascularity following CCET. In addition, whether epithelial stem cells can persist after transplantation is the key for CCET and COMET. Emerging evidence of long-term survival of cultivated epithelial cells after transplantation suggest that epithelial stem cells can be isolated and cultivated in vitro, and can re-establish the epithelial phenotype in vivo. Taken together, the merits of enhanced anti-angiogenic activity and the preservation of corneal epithelial stem cells encourage further application of this tissue engineering technique for ocular surface reconstruction.

Proteolytically Derived Endogenous Angioinhibitors Originating from the Extracellular Matrix

Angiogenesis, a neovascularization process induced from the existing parent blood vessels, is a prerequisite for many physiological and pathological conditions. Under physiological conditions it is regulated by a balance between endogenous angioinhibitors and angioactivators, and an imbalance between them would lead to pathological conditions such as cancer, age-related macular degeneration (AMD), diabetic retinopathy, cardiovascular diseases, etc. Several proteolytically generated endogenous molecules have been identified which exhibit angioinhibition and/or antitumor activities. These angioinhibitors interact with endothelial and tumor cells by binding to distinct integrins and initiate many of their intracellular signaling mechanisms regulating the cell survival and or apoptotic pathways. The present review will focus on the extracellular matrix derived angioinhibitors, and their mechanisms of actions that point to the clinical significance and therapeutic implications.

Tumor angiogenesis as a target for dietary cancer prevention

Between 2000 and 2050, the number of new cancer patients diagnosed annually is expected to double, with an accompanying increase in treatment costs of more than $80 billion over just the next decade. Efficacious strategies for cancer prevention will therefore be vital for improving patients' quality of life and reducing healthcare costs. Judah Folkman first proposed antiangiogenesis as a strategy for preventing dormant microtumors from progressing to invasive cancer. Although antiangiogenic drugs are now available for many advanced malignancies (colorectal, lung, breast, kidney, liver, brain, thyroid, neuroendocrine, multiple myeloma, myelodysplastic syndrome), cost and toxicity considerations preclude their broad use for cancer prevention. Potent antiangiogenic molecules have now been identified in dietary sources, suggesting that a rationally designed antiangiogenic diet could provide a safe, widely available, and novel strategy for preventing cancer. This paper presents the scientific, epidemiologic, and clinical evidence supporting the role of an antiangiogenic diet for cancer prevention.

Novel peptide-specific quantitative structure-activity relationship (QSAR) analysis applied to collagen IV peptides with antiangiogenic activity

Angiogenesis is the growth of new blood vessels from existing vasculature. Excessive vascularization is associated with a number of diseases including cancer. Antiangiogenic therapies have the potential to stunt cancer progression. Peptides derived from type IV collagen are potent inhibitors of angiogenesis. We wanted to gain a better understanding of collagen IV structure-activity relationships using a ligand-based approach. We developed novel peptide-specific QSAR models to study the activity of the peptides in endothelial cell proliferation, migration, and adhesion inhibition assays. We found that the models produced quantitatively accurate predictions of activity and provided insight into collagen IV derived peptide structure-activity relationships.

Regulation of endothelial cell functions by basement membrane- and arachidonic acid-derived products

Angiogenesis, the formation of new blood vessels from preexisting vasculature, is required for normal physiological as well as pathological events. The angiogenic process requires endothelial cells to proliferate, migrate, and undergo tubulogenesis. These multistep processes necessitate secretion of pro-angiogenic growth factors, activation of specific intracellular signaling, and interaction of endothelial cells with basement membrane (BM) extracellular matrix components. The generation and release of angiogenic molecules are highly regulated and are influenced by numerous factors, including BM-derived fragments, proteolytic enzymes, as well as metabolites of arachidonic acid (AA). The interactions between these key modulators of angiogenesis is extremely complex, as AA metabolites can regulate the synthesis of soluble angiogenic factors, BM components, as well as enzymes capable of cleaving BM components, which result in the generation of pro- and/or anti-angiogenic products. Furthermore, some BM-derived fragments can alter the expression of AA-converting enzymes and consequently the synthesis of angiogenic factors. In this review we describe the relationship between BM components and AA metabolites with respect to the regulation of endothelial cell functions in health and disease.

Endogenous Matrix-Derived Inhibitors of Angiogenesis

Endogenous inhibitors of angiogenesis are proteins or fragments of proteins that are formed in the body, which can inhibit the angiogenic process. These molecules can be found both in the circulation and sequestered in the extracellular matrix (ECM) surrounding cells. Many matrix-derived inhibitors of angiogenesis, such as endostatin, tumstatin, canstatin and arresten, are bioactive fragments of larger ECM molecules. These substances become released upon proteolysis of the ECM and the vascular basement membrane (VBM) by enzymes of the tumor microenvironment. Although the role of matrix-derived angiogenesis inhibitors is well studied in animal models of cancer, their role in human cancers is less established. In this review we discuss the current knowledge about these molecules and their potential use as cancer therapeutics and biomarkers.

Chlorthalidone Decreases Platelet Aggregation and Vascular Permeability and Promotes Angiogenesis

Variations in diuretic-mediated inhibition of carbonic anhydrase-dependent chloride transport in platelets and vascular smooth muscle could account for the contrasting efficacy of the thiazide and thiazide-like diuretics in reducing cardiovascular morbidity in patients with hypertension. We assessed platelet carbonic anhydrase activity and catecholamine-induced platelet aggregation in the presence of a thiazide and a “thiazide-like” inhibitor of the sodium-chloride cotransporter. Individual variation in platelet carbonic anhydrase activity correlated with contrasting sensitivity to epinephrine-mediated platelet aggregation. Both chlorthalidone, which potently inhibits platelet carbonic anhydrase, and bendroflumethiazide, which has much less effect on this enzyme, increased the amount of epinephrine needed to induce platelet aggregation when compared with the absence of a diuretic. However, chlorthalidone was significantly more effective than bendroflumethiazide in reducing epinephrine-mediated platelet aggregation. Chlorthalidone also induced marked changes in the number of gene transcripts for two proteins that mediate angiogenesis and vascular permeability, vascular endothelial growth factor C and transforming growth factor-β3; chlorthalidone and bendroflumethiazide had contrasting effects on the expression of vascular endothelial growth factor C. Chlorthalidone and bendroflumethiazide reduced vascular permeability to albumin, but only chlorthalidone increased angiogenesis. Thiazides and thiazide-like diuretics can comparably reduce blood pressure, but the drugs in this class are not all alike. It can be suggested from our findings that thiazide and thiazide-like diuretics vary in their pleiotropic effects on platelets and in the vasculature, and these differences could explain the contrasting ability of these drugs to reduce cardiovascular morbidity despite comparable reduction in blood pressure.

Effect of Borrelia burgdorferi OspC at the site of inoculation in mouse skin

The Borrelia burgdorferi surface lipoprotein OspC is a critical virulence factor, but its precise role in the establishment of B. burgdorferi infection remains unclear. To determine whether OspC affects the host response at the site of inoculation of the bacterium, the recruitment of macrophages and neutrophils and the production of cytokines were examined at the site of infection by wild-type, ospC mutant, and complemented mutant B. burgdorferi strains. Of the 21 cytokines tested, monocyte chemoattractant protein 1 (MCP-1), keratinocyte-derived chemokine (KC, CXCL1), and vascular endothelial growth factor (VEGF) were found at increased levels at the site of inoculation of B. burgdorferi, and the levels varied with the production of OspC at one or more time points over the 1-week course of infection. The kinetics of expression and the dependence on OspC production by B. burgdorferi varied among the cytokines. The production of KC and MCP-1, and the appearance of monocytic infiltrates, correlated with the presence of the bacteria rather than with OspC specifically. In contrast, VEGF production was not correlated simply to the presence of the bacteria and is influenced by the presence of OspC. In in vitro assays, OspC and B. burgdorferi expressing OspC stimulated the growth of endothelial cells more than did the controls. These data suggest the possibility of a novel role for OspC in the life of B. burgdorferi at the interface of its mammalian and tick hosts.