Collagen XVIII/endostatin structure and functional role in angiogenesis

Tofacitinib Regulates Endostatin via Effects on CD147 and Cathepsin S

Angiogenesis is critical for rheumatoid arthritis (RA) progression. The effects of tofacitinib, a JAK-STAT inhibitor used for RA treatment, on angiogenesis in RA are unclear. We, therefore, evaluated the levels of angiogenic factors in two systems of a human co-culture of fibroblast (HT1080) and monocytic (U937) cell lines treated with tofacitinib and in serum samples from RA patients before and after six months of tofacitinib treatment. Tofacitinib reduced CD147 levels, matrix metalloproteinase-9 (MMP-9) activity, and angiogenic potential but increased endostatin levels and secreted proteasome 20S activity. In vitro, tofacitinib did not change CD147 mRNA but increased miR-146a-5p expression and reduced STAT3 phosphorylation. We recently showed that CD147 regulates the ability of MMP-9 and secreted proteasome 20S to cleave collagen XVIIIA into endostatin. We show here that tofacitinib-enhanced endostatin levels are mediated by CD147, as CD147-siRNA or an anti-CD147 antibody blocked proteasome 20S activity. The correlation between CD147 and different disease severity scores supported this role. Lastly, tofacitinib reduced endostatin' s degradation by inhibiting cathepsin S activity and recombinant cathepsin S reversed this in both systems. Thus, tofacitinib inhibits angiogenesis by reducing pro-angiogenic factors and enhancing the anti-angiogenic factor endostatin in a dual effect mediated partly through CD147 and partly through cathepsin S.

Orthostatic hypotension is associated with higher levels of circulating endostatin

Aims

The pathophysiology of orthostatic hypotension (OH), a common clinical condition, associated with adverse outcomes, is incompletely understood. We examined the relationship between OH and circulating endostatin, an endogenous angiogenesis inhibitor with antitumour effects proposed to be involved in blood pressure (BP) regulation.

Methods and results

We compared endostatin levels in 146 patients with OH and 150 controls. A commercial chemiluminescence sandwich immunoassay was used to measure circulating levels of endostatin. Linear and multivariate logistic regressions were conducted to test the association between endostatin and OH. Endostatin levels were significantly higher in OH patients (59 024 ± 2513 pg/mL) vs. controls (44 090 ± 1978pg/mL, P < 0.001). A positive linear correlation existed between endostatin and the magnitude of systolic BP decline upon standing (P < 0.001). Using multivariate analysis, endostatin was associated with OH (adjusted odds ratio per 10% increase of endostatin in the whole study population = 1.264, 95% confidence interval 1.141-1.402), regardless of age, sex, prevalent cancer, and cardiovascular disease, as well as traditional cardiovascular risk factors.

Conclusion

Circulating endostatin is elevated in patients with OH and may serve as a potential clinical marker of increased cardiovascular risk in patients with OH. Our findings call for external validation. Further research is warranted to clarify the underlying pathophysiological mechanisms.

Angiogenesis inhibitor or aggressiveness marker? The function of endostatin in cancer through electrochemical biosensing

This work reports the first electrochemical bioplatform developed for the determination of human endostatin (HE), a biomarker with recognized antiangiogenic potential whose elevated circulating levels have also been associated with the development of aggressive cancers. The developed electroanalytical biotool combines the benefits of using magnetic microparticles for the implementation of sandwich immunoassays and amperometric transduction on disposable carbon electrodes. A limit of detection (LOD) of 34.1 pg mL-1 for HE standards and a selectivity suitable for its foray into the clinical oncology area, are demonstrated. The determination of HE in clinical samples such as lysates and secretomes of colorectal cancer (CRC) cells, plasma, and tissue samples from patients with CRC in different stages, has been faced with satisfactory results showing the ability for discriminating the metastatic capabilities of cells and for identifying and staging CRC patients. The developed bioplatform allows precise quantitative determinations, requiring minimal pre-treatments and sample amounts in only 75 min. In addition, due to the instrumentation and the type of substrates used in the detection step, the biotool is compatible with implementation in multiplexed and/or point-of-need devices, features in which this bioplatform is advantageous with respect to the enzyme linked immunosorbent assay (ELISA) or immunoblotting technologies.

Soluble CD147 regulates endostatin via its effects on the activities of MMP-9 and secreted proteasome 20S

During progression of rheumatoid arthritis (RA), angiogenesis provides oxygen and nutrients for the cells' increased metabolic demands and number. To turn on angiogenesis, pro-angiogenic factors must outweigh anti-angiogenic factors. We have previously shown that CD147/extracellular matrix metalloproteinase inducer (EMMPRIN) can induce the expression of the pro-angiogenic factors vascular endothelial growth factor (VEGF) and matrix metallopeptidase 9 (MMP-9) in a co-culture of the human HT1080 fibrosarcoma and U937 monocytic-like cell lines. However, whether CD147 influences anti-angiogenic factors was not known. We now show that relative to single cultures, the co-culture of these cells not only enhanced pro-angiogenic factors but also decreased the anti-angiogenic factors endostatin and thrombospondin-1 (Tsp-1), generally increasing the angiogenic potential as measured by a wound assay. Using anti-CD147 antibody, CD147 small interfering RNA (siRNA), and recombinant CD147, we demonstrate that CD147 hormetically regulates the generation of endostatin but has no effect on Tsp-1. Since endostatin is cleaved from collagen XVIII (Col18A), we applied different protease inhibitors and established that MMP-9 and proteasome 20S, but not cathepsins, are responsible for endostatin generation. MMP-9 and proteasome 20S collaborate to synergistically enhance endostatin generation, and in a non-cellular system, CD147 enhanced MMP-9 activity and hormetically regulated proteasome 20S activity. Serum samples obtained from RA patients and healthy controls mostly corroborated these findings, indicating clinical relevance. Cumulatively, these findings suggest that secreted CD147 mediates a possibly allosteric effect on MMP-9 and proteasome 20S activities and can serve as a switch that turns angiogenesis on or off, depending on its ambient concentrations in the microenvironment.

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.

A narrative review of the effects of dexamethasone on traumatic brain injury in clinical and animal studies: focusing on inflammation

Traumatic brain injury (TBI) is a type of brain injury resulting from a sudden physical force to the head. TBI can range from mild, such as a concussion, to severe, which might result in long-term complications or even death. The initial impact or primary injury to the brain is followed by neuroinflammation, excitotoxicity, and oxidative stress, which are the hallmarks of the secondary injury phase, that can further damage the brain tissue. Dexamethasone (DXM) has neuroprotective effects. It reduces neuroinflammation, a critical factor in secondary injury-associated neuronal damage. DXM can also suppress the microglia activation and infiltrated macrophages, which are responsible for producing pro-inflammatory cytokines that contribute to neuroinflammation. Considering the outcomes of this research, some of the effects of DXM on TBI include: (1) DXM-loaded hydrogels reduce apoptosis, neuroinflammation, and lesion volume and improves neuronal cell survival and motor performance, (2) DXM treatment elevates the levels of Ndufs2, Gria3, MAOB, and Ndufv2 in the hippocampus following TBI, (3) DXM decreases the quantity of circulating endothelial progenitor cells, (4) DXM reduces the expression of IL1, (5) DXM suppresses the infiltration of RhoA + cells into primary lesions of TBI and (6) DXM treatment led to an increase in fractional anisotropy values and a decrease in apparent diffusion coefficient values, indicating improved white matter integrity. According to the study, the findings show that DXM treatment has neuroprotective effects in TBI. This indicates that DXM is a promising therapeutic approach to treating TBI.

Extracellular Matrix of Echinoderms

This review considers available data on the composition of the extracellular matrix (ECM) in echinoderms. The connective tissue in these animals has a rather complex organization. It includes a wide range of structural ECM proteins, as well as various proteases and their inhibitors. Members of almost all major groups of collagens, various glycoproteins, and proteoglycans have been found in echinoderms. There are enzymes for the synthesis of structural proteins and their modification by polysaccharides. However, the ECM of echinoderms substantially differs from that of vertebrates by the lack of elastin, fibronectins, tenascins, and some other glycoproteins and proteoglycans. Echinoderms have a wide variety of proteinases, with serine, cysteine, aspartic, and metal peptidases identified among them. Their active centers have a typical structure and can break down various ECM molecules. Echinoderms are also distinguished by a wide range of proteinase inhibitors. The complex ECM structure and the variety of intermolecular interactions evidently explain the complexity of the mechanisms responsible for variations in the mechanical properties of connective tissue in echinoderms. These mechanisms probably depend not only on the number of cross-links between the molecules, but also on the composition of ECM and the properties of its proteins.

Reduced Cathepsin L expression and secretion into the extracellular milieu contribute to lung fibrosis in systemic sclerosis

OBJECTIVES

Lung fibrosis is the leading cause of death in SSc, with no cure currently available. Antifibrotic Endostatin (ES) production does not reach therapeutic levels in SSc patients, suggesting a deficit in its release from Collagen XVIII by the main cleavage enzyme, Cathepsin L (CTSL). Thus, elucidating a potential deficit in CTSL expression and activity unravels an underlying molecular cause for SSc-driven lung fibrosis.

METHODS

Fibrosis was induced experimentally using TGF-β in vitro, in primary human lung fibroblasts (pLFs), and ex vivo, in human lung tissues. ES and CTSL expression was quantified using ELISA, RT-qPCR, immunoblotting or immunofluorescence. Recombinant NC1-FLAG peptide was used to assess CTSL cleavage activity. CTSL expression was also compared between SSc vs normal (NL)-derived pLFs and lung tissues.

RESULTS

ES levels were significantly reduced in media conditioned by TGF-β-induced pLFs. TGF-β-stimulated pLFs significantly reduced expression and secretion of CTSL into the extracellular matrix (ECM). CTSL was also sequestered in its inactive form into extracellular vesicles, further reducing its availability in the ECM. Media conditioned by TGF-β-induced pLFs showed reduced cleavage of NC1-Flag and reduced release of the antifibrotic ES fragment. SSc-derived pLFs and lung tissues expressed significantly lower levels of CTSL compared with NL.

CONCLUSIONS

Our findings identify CTSL as a protein protective against lung fibrosis via its activation of antifibrotic ES, and whose expression in SSc pLFs and lung tissues is suppressed. Identifying strategies to boost CTSL endogenous levels in SSc patients could serve as a viable therapeutic strategy.

The Role of Extracellular Matrix Proteins in Breast Cancer

The extracellular matrix is a structure composed of many molecules, including fibrillar (types I, II, III, V, XI, XXIV, XXVII) and non-fibrillar collagens (mainly basement membrane collagens: types IV, VIII, X), non-collagenous glycoproteins (elastin, laminin, fibronectin, thrombospondin, tenascin, osteopontin, osteonectin, entactin, periostin) embedded in a gel of negatively charged water-retaining glycosaminoglycans (GAGs) such as non-sulfated hyaluronic acid (HA) and sulfated GAGs which are linked to a core protein to form proteoglycans (PGs). This highly dynamic molecular network provides critical biochemical and biomechanical cues that mediate the cell–cell and cell–matrix interactions, influence cell growth, migration and differentiation and serve as a reservoir of cytokines and growth factors’ action. The breakdown of normal ECM and its replacement with tumor ECM modulate the tumor microenvironment (TME) composition and is an essential part of tumorigenesis and metastasis, acting as key driver for malignant progression. Abnormal ECM also deregulate behavior of stromal cells as well as facilitating tumor-associated angiogenesis and inflammation. Thus, the tumor matrix modulates each of the classically defined hallmarks of cancer promoting the growth, survival and invasion of the cancer. Moreover, various ECM-derived components modulate the immune response affecting T cells, tumor-associated macrophages (TAM), dendritic cells and cancer-associated fibroblasts (CAF). This review article considers the role that extracellular matrix play in breast cancer. Determining the detailed connections between the ECM and cellular processes has helped to identify novel disease markers and therapeutic targets.

Novel biomarkers assist in detection of liver fibrosis in HCV patients

Background

Accurate staging in individuals infected with hepatitis C is imperative to understand their long-term risk for liver-related complications. Liver biopsy has a traditional role to determine the levels of liver fibrosis specifically in hepatitis C virus patients. However, the development of non-invasive options has reduced the utilization of biopsy in this population.

Main body of the abstract

Detecting fibrosis levels through blood samples is already an acceptable alternative to biopsy; however, the optimal non-invasive panel has yet to be defined. Our study indicated hyaluronic acid, collagen oligomeric matrix protein, collagen type IV, and liver fibrosis scoring systems to distinguish fibrosis patients from the non-fibrosis group.

Short conclusion

The combination of these novel biomarkers, H. A, CO-IV, and Comp tests, could be used to accurately stage individuals with hepatitis C.

Acute Exhaustive Exercise under Normoxic and Normobaric Hypoxic Conditions Differentially Regulates Angiogenic Biomarkers in Humans

Background and Objectives: Angiogenesis describes the outgrowth of new capillaries from already existing ones. Different biomarkers regulate this process. Physical exercise and hypoxia are key stimuli for the activation of different angiogenic molecules, such as the vascular endothelial growth factor (VEGF). matrix metalloproteases (MMPs)-2 and -9 or the extracellular matrix cleavage fragment endostatin. The present study aimed to investigate influences of short-term, intensive cycling exercise under both normoxic and normobaric hypoxic conditions on the mentioned parameters. Materials and Methods: Twelve male subjects (age: 23.3 ± 2.0 years) participated in the study. All subjects conducted four intensive cycling tests until individual exhaustion in a randomized order under the following conditions: normoxia, 2000 m, 3000 m and 4000 m above sea level. Blood samples were taken before (pre) and 10 min, 30 min, 60 min and 240 min post exercise and were analyzed by ELISA. Results: VEGF showed a significantly reduced concentration compared to the pre-value solely under 4000 m at 10 min post exercise. MMP-2 showed significantly reduced concentrations at 240 min post exercise under 4000 m. MMP-9 increased at 240 min post exercise under both 2000 m and 4000 m conditions. Endostatin was significantly increased at 10 min post exercise independently of the applied stimulus. Conclusions: The presented data show that intensive short-term exercise bouts facilitate the bioavailability of angiogenic, ECM (extracellular matrix)-related biomarkers. This finding is interesting for both health- and performance-related research as it demonstrates the positive effects of intensive short exercise interventions.

Diagnostic accuracy of hepatocyte growth factor, Fas/CD95 and Endostatin for non-invasive assessment of hepatic fibrosis in biopsy-proven hepatitis C virus patients

BACKGROUND/AIM

Evaluation of liver fibrosis in chronic hepatitis C patients (CHC) provides a high value, not only for the diagnosis of the disease, but also for the therapeutic decision. The aim of the current study is the construction of simple non-invasive and more accurate score for liver fibrosis staging in CHC patients and estimating its performance against three published non-invasive indexes.

MATERIAL AND METHODS

CHC patients were divided into two groups: an estimated group (n = 75) and validated group (n = 50). Liver fibrosis was tested in biopsies by Metavair score system. Fas/CD95, hepatocyte growth factor (HGF) and endostatin were assayed by enzyme linked immunosorbent assay (ELISA). Statistical analysis was performed by stepwise linear discriminate analysis and area under-receiver operating curves (AUCs).

RESULTS

The multivariate discriminate analysis (MDA) selects a function based on absolute values of five biochemical markers; FHEPA (Fas/CD95, HGF, Endostatin, Platelets&Albumin)-Test score = 1.2 × Fas/CD95 (ng/mL) + 0.006 × HGF (pg/mL) + 0.03 × Endostatin (ng/mL) - 0.007 × platelets count(10⁹/L)-3.6 × Albumin (g/dL) - 8.6.FHEPA-Test producesAUCs 0.99, 0.877 and 0.847 to discriminate patients with significant fibrosis (F2-F4), advanced fibrosis (F3-F4) and cirrhosis (F4), respectively.

CONCLUSION

FHEPA-Test is considered a novel non-invasive test which could be applied in assessment of liver fibrosis in HCV infected patients. Our novel score was more efficient than Immune Fibrosis Index, Fibrosis Index and FibroQ and thus it could be more applicable, feasible & economic for Egyptian HCV patients. Our Novel Scoring system could be globalized to other populations to confirm its advantageous use in early diagnosis of liver fibrosis.

Distribution and Function of Glycosaminoglycans and Proteoglycans in the Development, Homeostasis and Pathology of the Ocular Surface

The ocular surface, which forms the interface between the eye and the external environment, includes the cornea, corneoscleral limbus, the conjunctiva and the accessory glands that produce the tear film. Glycosaminoglycans (GAGs) and proteoglycans (PGs) have been shown to play important roles in the development, hemostasis and pathology of the ocular surface. Herein we review the current literature related to the distribution and function of GAGs and PGs within the ocular surface, with focus on the cornea. The unique organization of ECM components within the cornea is essential for the maintenance of corneal transparency and function. Many studies have described the importance of GAGs within the epithelial and stromal compartment, while very few studies have analyzed the ECM of the endothelial layer. Importantly, GAGs have been shown to be essential for maintaining corneal homeostasis, epithelial cell differentiation and wound healing, and, more recently, a role has been suggested for the ECM in regulating limbal stem cells, corneal innervation, corneal inflammation, corneal angiogenesis and lymphangiogenesis. Reports have also associated genetic defects of the ECM to corneal pathologies. Thus, we also highlight the role of different GAGs and PGs in ocular surface homeostasis, as well as in pathology.

Encapsulation of an endostatin peptide in liposomes: Stability, release, and cytotoxicity study

The endostatin protein is a potent inhibitor of angiogenesis and tumor growth. The anti-angiogenic and antitumor properties of full-length endostatin can be mimicked by its N-terminal segment, including residues 1-27. Therefore, our previous studies have shown that a mutant N-terminal peptide which the Zn-binding loop was replaced by a disulfide loop (referred to as the ES-SS peptide) has preserved antiangiogenic and antitumor properties compared to the native peptide. To increase stability and plasma half-life of the ES-SS peptide, the nano-sized liposomal formulations of the peptide with different ratio of phosphocholine (PC) were synthesized. The liposomal peptide formulations possessed an average size of around 100 nm with (-4 to -36 mv) in zeta potential. The encapsulation efficiency of the ES-SS peptide was in the range of 24-54% with different lipid: peptide molar ratios. In vitro release of the peptide from liposomes indicated a complete peptide release after 7 days. Cytotoxicity assay was evaluated using the human umbilical vein endothelial cells (HUVECs) for various concentrations of the liposomal peptide. The results depicted the gradual release of the peptide through liposomes. By comparing with the free peptide, the liposomal peptide formulations have indicated higher cell viability with IC₅₀ value about 0.1 μM. The peptide-liposome interactions, as well as the peptide effect on the liposome structure, were also investigated through coarse-grained molecular dynamics (CG-MD) simulation. The results revealed that the peptides were assembled in the hydrophilic core of the liposome. The peptide behavior in liposome can stabilize the liposome structure and be a response to the observed low peptide release rate. The investigation is promising for designing a liposome-based anti-angiogenesis peptide delivery system.

Serum endostatin level as a marker for coronary artery calcification in type 2 diabetic patients

Objective

To assess the relationship between serum endostatin (ES) and coronary artery calcification (CAC) in type 2 diabetic (T2DM) patients.

Methods

The study included 110 participants with coronary artery disease (CAD); 55 with T2DM, for serum ES levels by enzyme-linked immunosorbent assay and CAC by contrast-enhanced spiral computed tomography (CT).

Results

Mean serum ES value was 66.54 ng/mL [95% confidence interval (CI), 61.77-71.32 ng/mL]. Serum ES levels positively correlated with Agatston score index [ASI; r = 0.701, p < 0.001; high sensitive C-reactive protein (hs-CRP) r = 0.783, p < 0.001]. On multiple regression analysis, the highest three ES quartiles (2, 3, and 4) were related to ASI in diabetic patients, adjusted ES level was an independent predictor of CAD [odds ratio (OR) = 1.065; 95% CI, 1.008-1.126; p = 0.026] and for the number of coronary vessels affected (OR = 1.089; 95% CI, 1.018-1.164; p = 0.013) in T2DM patients. Receiver operating characteristics (ROC) analysis showed serum ES at a cutoff value of 86.5 ng/mL can predict the risk of CAC in T2DM, with a sensitivity of 74.1%, specificity of 71.4%, p < 0.001 and area under curve (AUC) of 0.776.

Conclusion

Measurement of serum ES levels can improve diagnosis of CAC and could be useful as a high sensitive marker for the presence and progression of atherosclerosis in T2DM patients.

Mediators of angiogenesis and fibrosis in IgG4-related disease

IgG4-related disease (IgG4-RD) is a rare fibro-inflammatory condition that can affect almost any organ, characterized by tumefactive lesions and often by eosinophilia and elevated serum IgG4 concentrations. The aim of the study is to analyze in IgG4-RD patients the serum levels of a group of cytokines and growth factors potentially involved in the regulation of fibrotic processes. In the sera of 12 patients affected by IgG4-RD and of 15 normal healthy subjects (NHS), pro-fibrogenic mediators (TGF-β1 and periostin) and pro- (VEGF and angiogenin-1) and anti- (endostatin and thrombospondin-1) angiogenic mediators were measured by sandwich enzyme immunoassay. Among mediators regulating fibrosis and angiogenesis, endostatin levels were significantly higher in IgG4-RD patients compared to NHS (p < 0.0001). No differences in the levels of TGF-β1, periostin, VEGF, angiogenin-1 and thrombospondin-1 were observed between groups. Our study suggests that among the mediators mainly involved in fibrosis and angiogenesis endostatin might play a role in the pathogenetic processes of IgG4-RD.

Noninvasive estimation of liver fibrosis in biopsy-proven hepatitis C virus-infected patients: angiogenic fibrogenic link

BACKGROUND/AIM

The assessment of liver fibrosis provides useful information not only for diagnosis but also for therapeutic decisions. This study aimed to develop and evaluate a predictive score named the angiogenic index (Angio-Index) for liver fibrosis staging and to compare Angio-Index by King, Gotebörg University Cirrhosis Index, Lok, FIB-4, and aspartate aminotranferase/alanine aminotranferase scores in hepatitis C virus-infected patients.

PATIENTS AND METHODS

Serum levels of angiopoietin-2, basic fibroblast growth factor, hepatocyte growth factor, and endostatin were assayed using an enzyme-linked immunosorbent assay in 122 HCV patients represented in two sets (estimation group and validation group). Stepwise linear discriminant analysis and area under receiver-operating characteristic curves (AUCs) were utilized to produce a predictive score comprising significant angiogenic biomarkers.

RESULTS

A novel score named the Angio-Index score was created on the basis of a combination of angiopoietin-2, basic fibroblast growth factor, hepatocyte growth factor, and endostatin. Angio-Index produces an AUC of 0.90 for significant fibrosis, 0.865 for advanced fibrosis, and 0.857 for cirrhosis. The Angio-Index score correctly classified 71% of the significant fibrosis (F2-F4) with a sensitivity of 93% and a specificity of 91%. The Angio-Index had a similar AUC in the validation study. The above six scores showed lower AUCs than Angio-Index.

CONCLUSION

Whereas liver biopsy is invasive, costly, and associated with complications, Angio-Index is simple, noninvasive, and more accurate; it may decrease the need for liver biopsy in Egyptian patients.

Endostatin and irradiation modifies the activity of ADAM10 and neprilysin in breast cancer cells

Angiogenesis, the formation of new blood vessels, is regarded as a key cancer cell property. Endostatin (ES) is a potential antiangiogenic agent and it may be useful when implemented in combination with other cancer therapeutic strategies. The present study investigated the in vitro effects of ES, radiotherapy (RT) or combination therapy (ES + RT) on two important proteases, a disintegrin and metalloproteinase domain‑containing protein 10 (ADAM10) and neprilysin (NEP) in 4T1 mouse breast cancer cells and the more metastatic phenotype of 4THMpc breast cancer cells. 4T1 and 4THMpc cells were treated with recombinant murine ES (4 µg/ml) alone, RT (45 Gy) alone or with ES + RT. ADAM10 enzyme activity was determined using a tumor necrosis factor‑α converting enzyme (α‑secretase) activity assay kit, and NEP enzyme activity was measured with a fluorometric assay based on the generation of free dansyl‑D‑Ala‑Gly from N-dansyl-Ala-Gly-D-nitro-Phe-Gly, the substrate of NEP. Western blotting analysis was performed to determine whether the altered enzyme activity levels of the two cell lines occurred due to changes in expression level. These data indicate that ES independently potentiates the activity of ADAM10 and NEP enzymes in 4T1 and 4THMpc breast cancer cells.

Decoding the Matrix: Instructive Roles of Proteoglycan Receptors

The extracellular matrix is a dynamic repository harboring instructive cues that embody substantial regulatory dominance over many evolutionarily conserved intracellular activities, including proliferation, apoptosis, migration, motility, and autophagy. The matrix also coordinates and parses hierarchical information, such as angiogenesis, tumorigenesis, and immunological responses, typically providing the critical determinants driving each outcome. We provide the first comprehensive review focused on proteoglycan receptors, that is, signaling transmembrane proteins that use secreted proteoglycans as ligands, in addition to their natural ligands. The majority of these receptors belong to an exclusive subset of receptor tyrosine kinases and assorted cell surface receptors that specifically bind, transduce, and modulate fundamental cellular processes following interactions with proteoglycans. The class of small leucine-rich proteoglycans is the most studied so far and constitutes the best understood example of proteoglycan-receptor interactions. Decorin and biglycan evoke autophagy and immunological responses that deter, suppress, or exacerbate pathological conditions such as tumorigenesis, angiogenesis, and chronic inflammatory disease. Basement membrane-associated heparan sulfate proteoglycans (perlecan, agrin, and collagen XVIII) represent a unique cohort and provide proteolytically cleaved bioactive fragments for modulating cellular behavior. The receptors that bind the genuinely multifactorial and multivalent proteoglycans represent a nexus in understanding basic biological pathways and open new avenues for therapeutic and pharmacological intervention.

Endostar, a novel human recombinant endostatin, attenuates liver fibrosis in CCl4-induced mice

Decreasing hepatic fibrosis remains one of the major therapeutic challenges in hepatology. The present study aims to evaluate the effect of Endostar on both CCl4-induced liver fibrosis in mice and a hepatic stellate cell (HSC) line. Two main models were studied: (i) a liver fibrosis model was induced in BALB/c mice using CCl4 by intraperitoneal injection for six weeks. Six animal groups were studied: group 1: normal animals; group 2: CCl4-induced liver fibrosis; group 3: CCl4 + Endostar 20 mg/kg/d, six weeks; group 4: CCl4 + Endostar 10 mg/kg/d, six weeks; group 5: CCl4 + Endostar 20 mg/kg/d, four weeks; group 6: CCl4 + Endostar 10 mg/kg/d, four weeks corresponded to different Endostar doses and duration of administration. Liver fibrosis was evaluated by histopathological staining and liver hydroxyproline content. Expressions of collagen type I, α-smooth muscle actin ( α-SMA), TGF-β1 and VEGFR were measured by real-time polymerase chain reaction (PCR). (ii) A liver cell model. HSC-T6 cells were cultured with or without Endostar for 12 h or 24 h. Expressions of collagen type I, α-SMA, and TGF-β1 were measured by real-time PCR. Collagen I and transforming growth factor β1 (TGF-β1) contents in cell supernatant were measured by enzyme-linked immunosorbent assay. As compared to the group without Endostar, liver fibrosis scores and hydroxyproline content were decreased in both Endostar groups ( P < 0.05). Moreover, Endostar inhibited the hepatic expression of α-SMA, TGF-β1, Collagen-1, VEGFR1, and VEGFR2 mRNA ( P < 0.05). In the HSC-T6 cell line model, Endostar profoundly inhibited the expression of α-SMA, Collagen-1, and TGF-β1 mRNA. Expressions of Collagen-1 and TGF-β1 protein were decreased in the Endostar group as compared to the normal controls in the supernatant of HSC-T6 cells ( P < 0.05). Endostar decreased both liver fibrosis in CCl4-induced mice and collagen synthesis in HSCs in vitro. Therefore, this recombinant human endostatin is a promising compound for counteracting liver fibrosis.

Pulmonary arteriovenous malformations after the superior cavopulmonary shunt: mechanisms and clinical implications

Children with functional single ventricle heart disease are commonly palliated down a staged clinical pathway toward a Fontan completion procedure (total cavopulmonary connection). The Fontan physiology is fraught with long-term complications associated with lower body systemic venous hypertension, eventually resulting in significant morbidity and mortality. The bidirectional Glenn shunt or superior cavopulmonary connection (SCPC) is commonly the transitional stage in single ventricle surgical management and provides excellent palliation. Some studies have demonstrated lower morbidity and mortality with the SCPC when compared with the Fontan. Unfortunately the durability of the SCPC is significantly limited by the development of pulmonary arteriovenous malformations (PAVMs) which have been commonly attributed to the absence of hepatic venous blood flow and the lack of pulsatile flow to the affected lungs. Abnormal angiogenesis has been suggested as a final common pathway to PAVM development. Understanding these fundamental mechanisms through the investigation of angiogenic pathways associated with the pathogenesis of PAVMs would help to develop medical therapies that could prevent or reverse this complication following SCPC. Such therapies could improve the longevity of the SCPC, potentially eliminate or significantly postpone the Fontan completion with its associated complications, and improve long-term survival in children with single ventricle disease.

Antiangiogenic strategies in hepatocellular carcinoma: current status

Hepatocellular carcinoma is a leading cause of cancer death worldwide in both adult and pediatric patients. Despite many options, no ideal treatment exists for this highly malignant tumor, and management strategies have varied accordingly. Angiogenesis, the formation of new blood vessels, is an essential component of hepatocellular carcinoma biology. Innovative approaches such as targeting the nontransformed, less resistant, tumor-supporting endothelial cells are currently under investigation in hepatocellular carcinoma. This review will focus on the current knowledge of the pathophysiology of hepatocellular carcinoma angiogenesis, as well as the reported data with angiogenesis inhibitors against hepatocellular carcinoma.

Endostatin and Thrombospondin-1 levels are increased in the sera of patients with chronic spontaneous urticaria

Chronic urticaria (CU) is a common disease characterized by recurrent itchy wheals and/or angioedema for more than 6 weeks. Increased levels of the pro-angiogenic mediator vascular endothelial growth factor (VEGF) have been described in skin disorders, such as chronic urticaria (CU), psoriasis and atopic dermatitis. Up to now, no data on the role of VEGF endogenous inhibitors Endostatin (ES) and Thrombospondin-1 (TSP-1) in CU are available. The aim of our study is to investigate the potential involvement of ES and TSP-1 in patients with chronic spontaneous urticaria (CSU). The levels of ES and TSP-1 were measured in the sera of 106 adult patients with CSU and 98 healthy subjects by enzyme immunoassays. The serum levels of the anti-angiogenic mediators ES and TSP-1 resulted significantly higher in CSU than in control subjects. Analysis of these mediators in CSU sub-groups, defined by the results of the autologous serum skin test (ASST), identified a significant increase of ES and TSP-1 in both ASST-positive and ASST-negative sub-groups as compared to the controls. Levels of ES and TSP-1 do not parallel the disease severity in CSU. Our study suggests that the extracellular matrix (ECM) fragments ES and TSP-1 with anti-angiogenic activity play a potential role in the pathogenesis of CSU but do not parallel disease activity.

Serum levels of angiogenic and anti-angiogenic factors: their prognostic relevance in locally advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prototype tumor wherein angiogenesis plays a vital role in its progression. The role of VEGF, a major angiogenic factor in HCC is known; however, the role of anti-angiogenic factors simultaneously with the angiogenic factors has not been studied before. Hence, in this study, the serum levels of major angiogenic [Vascular Endothelial Growth Factor (VEGF), angiopoietin-2 (Ang-2)] and anti-angiogenic (endostatin, angiostatin) factors were analyzed and correlated with clinico-radiological features and with outcome. A total of 150 patients (50 HCC, 50 cirrhosis and 50 chronic hepatitis) and 50 healthy controls were enrolled in this study. Serum levels of VEGF, Ang-2, endostatin, and angiostatin were estimated by enzyme-linked immunosorbent assay. HCC shows significantly elevated serum levels of angiogenic factors VEGF and Ang-2 and of anti-angiogenic factors endostatin and angiostatin. ROC curve analysis for serum VEGF yielded an optimal cut-off value of 225.14 pg/ml, with a sensitivity of 78 % and specificity of 84.7 % for a diagnosis of HCC and its distinction from other group. Using this value, the univariate and multivariate analysis revealed significantly poor outcome in patients with higher levels of serum VEGF (p = 0.009). Combinatorial analysis revealed that patients with higher levels of both angiogenic and anti-angiogenic factors showed poor outcome. Serum VEGF correlates with poor survival of HCC patients and, therefore, serves as a non-invasive biomarker of poor prognosis. Moreover, elevated levels of anti-angiogenic factors occur endogenously in HCC patients.

Endostatin, an inhibitor of angiogenesis, decreases after bidirectional superior cavopulmonary anastamosis

Pulmonary arteriovenous malformations (PAVMs) are a common source of morbidity after bidirectional superior cavopulmonary anastomosis (Glenn). The diversion of hepatic venous effluent away from the pulmonary circulation after Glenn appears to play a significant role in the pathogenesis of PAVMs. Although the liver is known to produce factors that regulate vascular development, specific hepatic inhibitors of angiogenesis have not been described in the post-Glenn population. Endostatin, produced from its precursor collagen XVIII, is a potent inhibitor of angiogenesis produced by the liver. This study aimed to investigate the hypothesis that endostatin levels decrease in patients after Glenn. Levels of endostatin and its precursor, long-type collagen XVIII, were determined by enzyme-linked immunoassay and immunoprecipitation, respectively, for serum samples from 38 patients undergoing Glenn, total cavopulmonary anastomosis (Fontan), or biventricular repair of cardiac defects. Samples were obtained before surgery and 24 h afterward. In patients undergoing a bidirectional Glenn procedure, endostatin levels decreased after surgery (n = 17; 4.42 vs 3.34 ng/ml; p < 0.001), and long type-collagen XVIII levels increased by 200 % (n = 10; p = 0.0001). However, endostatin levels did not change after surgery in patients undergoing Fontan (n = 13) or biventricular repair (n = 8). In patients undergoing Fontan, long-type collagen XVIII increased by 18 % (p < 0.01), whereas in control subjects, the levels were unchanged. These data suggest that the diversion of hepatic blood flow away from the pulmonary circulation in patients after the Glenn procedure inhibits endostatin production from collagen XVIII, resulting in decreased circulating serum endostatin levels. A decrease in endostatin may promote angiogenesis. The mechanism whereby the pulmonary circulation processes endostatin and its potential role in the pathogenesis of PAVMs warrant further study.

Human pathogens utilize host extracellular matrix proteins laminin and collagen for adhesion and invasion of the host

Laminin (Ln) and collagen are multifunctional glycoproteins that play an important role in cellular morphogenesis, cell signalling, tissue repair and cell migration. These proteins are ubiquitously present in tissues as a part of the basement membrane (BM), constitute a protective layer around blood capillaries and are included in the extracellular matrix (ECM). As a component of BMs, both Lns and collagen(s), thus function as major mechanical containment molecules that protect tissues from pathogens. Invasive pathogens breach the basal lamina and degrade ECM proteins of interstitial spaces and connective tissues using various ECM-degrading proteases or surface-bound plasminogen and matrix metalloproteinases recruited from the host. Most pathogens associated with the respiratory, gastrointestinal, or urogenital tracts, as well as with the central nervous system or the skin, have the capacity to bind and degrade Lns and collagen(s) in order to adhere to and invade host tissues. In this review, we focus on the adaptability of various pathogens to utilize these ECM proteins as enhancers for adhesion to host tissues or as a targets for degradation in order to breach the cellular barriers. The major pathogens discussed are Streptococcus, Staphylococcus, Pseudomonas, Salmonella, Yersinia, Treponema, Mycobacterium, Clostridium, Listeria, Porphyromonas and Haemophilus; Candida, Aspergillus, Pneumocystis, Cryptococcus and Coccidioides; Acanthamoeba, Trypanosoma and Trichomonas; retrovirus and papilloma virus.

Novel medical therapies of recurrent and metastatic gastroenteropancreatic neuroendocrine tumors

Neuroendocrine tumors (NETs) of the gastrointestinal tract and pancreas are slow-growing but commonly advanced malignancies with increasing incidence and prevalence. While locoregional disease can be effectively managed with resection, treatment of recurrent, progressive or metastatic disease has until recently been limited to palliative embolization and cytoreducitve surgery, with cytotoxic chemotherapeutic agents being the last resort. However, novel molecular targeted therapies inhibiting malignant cell proliferation and neoangiogenesis, as well as new cytotoxic chemotherapy drugs and somatostatin analogues, are all being investigated for their potential use in advanced neuroendocrine tumors. Long-acting release forms of octreotide have been shown to not only improve symptoms in carcinoid syndrome but to also delay progression of gastrointestinal NETs. On the other hand, phase III trials have demonstrated everolimus (with octreotide) and sunitinib to increase progression-free survival in pancreatic NETs. Use of bevacizumab has also shown promise in a phase II study, and results of an ongoing phase III trial comparing it to interferon are eagerly expected. Use of radiolabeled somatostatin analogues is still under investigation, though several phase II studies are encouraging. New cytotoxic agents, most notably temozolomide and capecitabine, are already in use, but their relative effectiveness compared to streptozocin in pancreatic NETs is yet to be determined.

Genotype analysis of the human endostatin variant p.D104N in benign and malignant adrenocortical tumors

OBJECTIVE

Endostatin is a potent endogenous inhibitor of angiogenesis. It is derived from the proteolytic cleavage of collagen XVIII, which is encoded by the COL18A1 gene. A polymorphic COL18A1 allele encoding the functional polymorphism p.D104N impairs the activity of endostatin, resulting in a decreased ability to inhibit angiogenesis. This polymorphism has been previously analyzed in many types of cancer and has been considered a phenotype modulator in some benign and malignant tumors. However, these data are controversial, and different results have been reported for the same tumor types, such as prostate and breast cancer. The purpose of this study was to genotype the p.D104N variant in a cohort of pediatric and adult patients with adrenocortical tumors and to determine its possible association with the biological behavior of adrenocortical tumors.

METHODS

DNA samples were obtained from 38 pediatric and 56 adult patients (0.6-75 yrs) with adrenocortical tumors. The DNA samples were obtained from peripheral blood, frozen tissue or paraffin-embedded tumor blocks when blood samples or fresh frozen tissue samples were unavailable. Restriction fragment length polymorphism analysis was used to genotype the patients and 150 controls. The potential associations of the p.D104N polymorphism with clinical and histopathological features and oncologic outcome (age of onset, tumor size, malignant tumor behavior, and clinical syndrome) were analyzed.

RESULTS

Both the patient group and the control group were in Hardy-Weinberg equilibrium. The frequencies of the p.D104N polymorphism in the patient group were 81.9% (DD), 15.9% (DN) and 2.2% (NN). In the controls, these frequencies were 80.6%, 17.3% and 2.0%, respectively. We did not observe any association of this variant with clinical or histopathological features or oncologic outcome in our cohort of pediatric and adult patients with adrenocortical tumors.

Biomarker analysis in a phase III study of pemetrexed-carboplatin versus etoposide-carboplatin in chemonaive patients with extensive-stage small-cell lung cancer

BACKGROUND

Clinical results of a randomized phase III trial comparing pemetrexed-carboplatin (PC) with etoposide-carboplatin (EC) in chemonaive patients with extensive-stage disease small-cell lung cancer (ED-SCLC) resulted in trial closure for futility; biomarker analyses using immunohistochemistry (IHC) and single-nucleotide polymorphisms (SNPs) are described herein.

PATIENTS AND METHODS

Thymidylate synthase (TS), excision repair cross complementing-1 (ERCC1), glycinamide ribonucleotide formyltransferase (GARFT), and folylpolyglutamate synthetase (FPGS) were investigated using IHC (n=395). SNPs were genotyped for TS, FPGS, γ-glutamyl hydrolase (GGH), methylenetetrahydrofolate reductase (MTHFR), folate receptor-α FR-α, and solute carrier 19A1 (SLC19A1; n=611).

RESULTS

None of the IHC biomarkers (folate pathway or ERCC1) were found to be predictive or prognostic in this setting. rs2838952 (adjacent to SLC19A1) had significant treatment-independent association with overall survival (OS; hazard ratio 0.590, P=0.01). Nine GGH-associated SNPs interacted with rs3788205 (SLC19A1) for OS on the PC arm. rs12379987 (FPGS) interacted with treatment for OS (interaction P=0.036).

CONCLUSION

Potential ERCC1 and folate pathway IHC biomarkers failed to predict outcome in either study arm in ED-SCLC. SNPs in regions including FPGS and SLC19A1 and interacting SNPs in GGH and SLC19A1 were associated with differences in OS; however, none of these SNPs predicted for greater survival with PC over EC.

A potential therapeutic strategy for inhibition of ocular neovascularization with a new endogenous protein: rhEDI-8t

BACKGROUND

Endogenous angiogenesis inhibitors act as natural negative feedback in the focal area during the neovascularization process, and have less interference on physiological angiogenesis, and thus fewer negative side-effects. These inhibitors are potential candidates to combine with or substitutes for current popular anti-angiogenesis treatments to have synergistic effect. In this study, the effects of recombinant endothelial growth inhibitor protein (rhEDI-8t), a novel endogenous protein originated from collagen VIII, was investigated on ocular neovascularization (NV). Endostatin, a well-identified endogenous angiogenesis inhibitor, was compared in parallel and served as a positive control.

METHODS

The inhibitory effect of rhEDI-8t on vascular endothelial cells was evaluated by a human umbilical vascular endothelial cells (HUVEC) proliferation test and a bovine aortic endothelial cells (BAEC) migration experiment. The effect of rhEDI-8t on ocular NV was further investigated in mice with choroidal neovascularization (choroidal NV) induced by laser, ischemic retinopathy and transgenic mice with expression of VEGF in photoreceptors (rho/VEGF) respectively.

RESULTS

RhEDI-8t inhibited the growth of HUVECs and migration of BAECs stimulated by basic fibroblast growth factor (bFGF). Mice intravitreally treated with rhEDI-8t showed a significant reduction of choroidal NV, retinal NV and subretinal NV.

CONCLUSION

Endogenous angiogenesis inhibitor rhEDI-8t showed a potent anti-angiogenesis effect in both in vitro and in vivo experiments. It contributed to the suppression of ocular NV. The study suggested that rhEDI-8t could be a subsidiary potent therapeutic medicine in addition to anti-VEGF therapy in future clinical anti-angiogenesis treatment.

Proteoglycans: key regulators of pulmonary inflammation and the innate immune response to lung infection

Exposure to viruses and bacteria results in lung infections and places a significant burden on public health. The innate immune system is an early warning system that recognizes viruses and bacteria, which results in the rapid production of inflammatory mediators such as cytokines and chemokines and the pulmonary recruitment of leukocytes. When leukocytes emigrate from the systemic circulation through the extracellular matrix (ECM) in response to lung infection they encounter proteoglycans, which consist of a core protein and their associated glycosaminoglycans. In this review, we discuss how proteoglycans serve to modify the pulmonary inflammatory response and leukocyte migration through a number of different mechanisms including: (1) The ability of soluble proteoglycans or fragments of glycosaminoglycans to activate Toll-like receptor (TLRs) signaling pathways; (2) The binding and sequestration of cytokines, chemokines, and growth factors by proteoglycans; (3) the ability of proteoglycans and hyaluronan to facilitate leukocyte adhesion and sequestration; and (4) The interactions between proteoglycans and matrix metalloproteinases (MMP) that alter the function of these proteases. In conclusion, proteoglycans fine-tune tissue inflammation through a number of different mechanisms. Clarification of the mechanisms whereby proteoglycans modulate the pulmonary inflammatory response will most likely lead to new therapeutic approaches to inflammatory lung disease and lung infection.

Cell adhesive peptide screening of the mouse laminin α1 chain G domain

Cell adhesive peptides have been widely applied for therapeutic drugs, drug delivery systems, and biomaterials. Previously, we identified various cell adhesive sequences in the G domains of four laminin α chains (α2-α5) by the systematic soluble peptide screening. We also identified five cell-binding sequences in the laminin α1 chain G domain using synthetic peptide-polystyrene beads. Here, we re-screened cell adhesive peptides in the laminin α1 chain G domain by the systematic soluble peptides screening. The 110 soluble peptides were evaluated for their cell adhesive activities using human fibrosarcoma HT1080 cells and human dermal fibroblasts. Fourteen peptides were newly identified as a cell adhesive. Additionally, four peptides (AG22: SSFHFDGSGYAM, AG42: TFDLLRNSYGVRK, AG76: HQNQMDYATLQLQ, AG86: LGGLPSHYRARNI) promoted integrin-mediated cell adhesion. Further, neurite outgrowth activity with rat pheochromocytoma PC12 cells was evaluated and two peptides (AG20: SIGLWNYIEREGK, AG26: SPNGLLFYLASNG) were newly identified for neurite outgrowth activity. These results suggested that the systematic soluble peptides screening approach is an accurate and powerful strategy for finding biologically active sequences. The active sequences newly identified here could be involved in the biological functions of this domain. The active peptides are useful for evaluating molecular mechanisms of laminin-receptor interactions and for developing cell adhesive biomaterials.

Cationic liposome coupled endostatin gene for treatment of peritoneal colon cancer

Therapy targeting cancer blood vessels requires unwavering pharmacokinetics of antiangiogenic therapeutics to neutralize the excess pro-angiogenic factors constantly secreted by tumor cells. Gene therapies have been explored to effectively create a microenvironment less favorable for angiogenesis and tumor expansion. In this study, we examined the inhibitory effect of cationic liposome coupled with the murine endostatin gene (Lipo/mEndo) on growth of intraperitoneal disseminated colon cancer models. Intraperitoneal injection of Lipo/mEndo inhibited bioluminescent signals emitted from CT26 colon cancer cells stably expressing luciferase in the living mice and prolonged their survival times. Endostatin gene therapy suppressed the colony forming capability and VEGF concentration of ascites obtained from treated mice by 74 and 60%, respectively. When tested in a similar model using HCT116 human colon cancer cells, Lipo/mEndo and bevacizumab displayed comparable repressive effects on ascites formation and tumor foci dissemination on mesentery of experimental mice. Our results implicate that cationic liposome coupled endostatin gene therapy may be a clinically effective treatment for intraperitoneal disseminated colon cancer.

Role of angiogenesis in bladder response to partial outlet obstruction

Benign prostatic hyperplasia (BPH) is a disease that has its etiology in the abnormal growth of the adult human prostate gland that accompanies the aging process in men. The symptomatic presentation of this disease, however, is related largely to degenerative changes in the bladder that occur as a result of the increasing urethral resistance and partial bladder outlet obstruction (PBOO) caused by the growing prostate gland. BPH is characterized by bladder hypertrophy, significant decreases in urinary flow and compliance, presence of residual urine after voiding, voiding urgency and incontinence (). Obstructed bladder dysfunction secondary to BPH is a slow, progressive disease that is so strongly associated with human aging that it is an expected occurrence of the male aging process. Although the symptoms of BPH are usually not life threatening, they effect an extremely negative quality of life for men who suffer from them. However, many men delay seeking medical treatment for early BPH since bladder function can remain relatively normal as the hypertrophying bladder initially compensates for the progressive increase in urethral resistance caused by prostatic obstruction. The limited changes in micturition pressure and flow characteristics that occur during compensated function are not usually disabling enough to motivate seeking medical attention, which, often, is not sought until the symptoms become typical of advanced disease. Recent advances in detection methods enable identification of patients with significant BPH during compensation before the bladder becomes dysfunctional (decompensated). A more complete understanding of the disease processes that underlie the loss of bladder function associated with BPH might enable the development of treatments that better protect these early-stage BPH patients from the more debilitating aspects of the disease. This review updates the understanding of obstructive bladder dysfunction via the use of animal models.

Basement membrane proteoglycans: modulators Par Excellence of cancer growth and angiogenesis

Proteoglycans located in basement membranes, the nanostructures underling epithelial and endothelial layers, are unique in several respects. They are usually large, elongated molecules with a collage of domains that share structural and functional homology with numerous extracellular matrix proteins, growth factors and surface receptors. They mainly carry heparan sulfate side chains and these contribute not only to storing and preserving the biological activity of various heparan sulfate-binding cytokines and growth factors, but also in presenting them in a more "active configuration" to their cognate receptors. Abnormal expression or deregulated function of these proteoglycans affect cancer and angiogenesis, and are critical for the evolution of the tumor microenvironment. This review will focus on the functional roles of the major heparan sulfate proteoglycans from basement membrane zones: perlecan, agrin and collagen XVIII, and on their roles in modulating cancer growth and angiogenesis.

Serum cystatin C level, kidney disease markers, and incidence of age-related macular degeneration: the Beaver Dam Eye Study

OBJECTIVE

To examine the associations of the serum cystatin C level and chronic kidney disease with the incidence of age-related macular degeneration (AMD) over 15 years.

METHODS

In this population-based cohort study of 4926 individuals aged 43 to 86 years at baseline, 3779 participated in 1 or more follow-up examinations. Age-related macular degeneration was determined by grading photographs of the macula. Individuals were defined as having mild or moderate to severe chronic kidney disease based on a value of more than 45 mL/min/1.73 m(2) to 60 mL/min/1.73 m(2) or less and 45 mL/min/1.73 m(2) or less, respectively, according to the Modification of Diet in Renal Disease Study equation.

RESULTS

While controlling for age and other risk factors, the level of serum cystatin C at baseline was associated with the incidence of early AMD (odds ratio per log standard deviation [95% confidence interval], 1.16 [1.01-1.35]) and exudative AMD (1.42 [1.03-1.96]) but not geographic atrophy (0.89 [0.56-1.41]) or progression of AMD (1.02 [0.88-1.18]). Mild chronic kidney disease was associated with the 15-year cumulative incidence of early AMD (odds ratio per log standard deviation, 1.36 [95% confidence interval, 1.00-1.86]) but not the incidence of other AMD end points.

CONCLUSION

There is a relationship between the level of serum cystatin C and chronic kidney disease with the incidence of AMD. The underlying biological processes remain to be determined.

Implications of bevacizumab on vascular endothelial growth factor and endostatin in human choroidal neovascularisation

AIM

To evaluate the implications of intravitreal bevacizumab on proangiogenic vascular endothelial growth factor (VEGF) with regard to the endogenous angiogenesis inhibitor endostatin in human choroidal neovascularisation (CNV) secondary to age-related macular degeneration.

METHODS

Retrospective review of an interventional case series of 48 patients who underwent full macular translocation surgery with removal of CNV. Twenty-five patients were treated with intravitreal bevacizumab injection 1 to 154 days prior to surgery (bevacizumab CNV). Twenty-three CNV without any kind of previous treatment were used as controls (control CNV). CNV were stained for CD34, cytokeratin18, VEGF, endostatin and E-selectin. A "predominance score of VEGF over endostatin" (PS) was defined by the difference between VEGF and endostatin staining scores.

RESULTS

Bevacizumab CNV revealed a weaker VEGF expression in endothelial cells (p = 0.0245) but significantly more intense endostatin in retina pigment epithelium (RPE) (p = 0.0001) and stroma (p<0.0001). Consequently, PS was significantly lower in RPE (p = 0.02), vessels (p = 0.03) and stroma (p = 0.0004) in bevacizumab CNV. The intensity of E-selectin expression in bevacizumab CNV was comparable with that in control CNV.

CONCLUSIONS

A shift within the angiogenic balance in terms of decreased VEGF predominance over endostatin is detected in human CNV treated with bevacizumab.

The role of vascular endothelial growth factor and other endogenous interplayers in age-related macular degeneration

Age-related macular degeneration (AMD) is a multifaceted disease characterized by early subclinical changes at the choroidea-retinal pigment epithelium interface. Both the causal and formal pathogenesis of the disease is still puzzling. Similarly, the reason for progression into two distinct late forms which are "geographic atrophy" and "choroidal neovascularization" remains enigmatic. Late changes are usually responsible for the dramatic loss in central function that has a devastating effect on quality of life. In industrialized countries the disease is a major cause for visual disability among persons over 60 years of age. Due to demographic right-shift and increased life expectancy, AMD is not only a medical problem but will have a pronounced socio-economic effect. Neovascular AMD with the development of choroidal neovascularization in the macular area accounts for 80% of the severe loss of visual acuity due to AMD. In the last decades, treatment modes were merely based on the destruction or surgical removal of the neovascular complex. In the present, however, the philosophical approach to treat the disease is changing to a pathology modifying manner. Intelligent targeting of the involved relevant factors and pathways should stop disease progression, reduce complications and improve vision. The first step into this new era has been accomplished with the introduction of antiangiogenic agents. The new agents act either directly on vascular endothelial growth factor (VEGF) or indirectly on its functional cascade. VEGF makes a fundamental contribution to neovascular processes but it also acts in physiological pathways. The main purpose of this review is to summarize its physiological role especially within the eye, the role in the development of AMD and to understand and foresee both the benefits and potential side-effects of the anti-VEGF-based therapy.

Reduction of endogenous angiogenesis inhibitors in Bruch's membrane of the submacular region in eyes with age-related macular degeneration

OBJECTIVES

To determine the relative levels of 3 potent inhibitors of angiogenesis (endostatin, pigment epithelium-derived factor, and thrombospondin 1) in the retinal pigment epithelium-Bruch's membrane-choriocapillaris complex in the submacular region in aged control eyes and eyes with age-related macular degeneration (AMD).

METHODS

Immunohistochemical analysis with antibodies against endostatin, pigment epithelium-derived factor, and thrombospondin 1 was performed on the macular region of aged control donor eyes (n = 8; mean age, 79.8 years) and eyes with AMD (n = 12; mean age, 83.9 years). Three independent masked observers scored the reaction product (scored from 0-7). Mean scores from the control eyes and the eyes with AMD were analyzed using 1-way analysis of variance and unpaired t test.

RESULTS

In control eyes, strong immunoreactivity of all 3 inhibitors was observed in the retinal pigment epithelium-Bruch's membrane-choriocapillaris complex. Immunoreactivity for endostatin, pigment epithelium-derived factor, and thrombospondin 1 in Bruch's membrane was significantly lower in eyes with AMD compared with aged control eyes (analysis of variance, P = .003, P = .009, and P < .001, respectively). In the choriocapillaris, a significant reduction was observed in endostatin (analysis of variance, P = .02) and thrombospondin 1 (analysis of variance, P = .005) in eyes with AMD.

CONCLUSIONS

These findings suggest that endogenous angiogenesis inhibitors in the retinal pigment epithelium-Bruch's membrane-choriocapillaris complex may provide a biochemical barrier for choroidal neovascular invasion.

CLINICAL RELEVANCE

Decreased levels of angiogenic inhibitors at the retinal pigment epithelium-Bruch's membrane-choriocapillaris complex in eyes with AMD make Bruch's membrane vulnerable to choroidal neovascularization.

MT1-MMP is required for efficient tumor dissemination in experimental metastatic disease

Membrane-type I matrix metalloproteinase (MT1-MMP) is associated with multiple forms of cancer including mammary cancer. To directly evaluate the significance of MT1-MMP expression in tumor progression and metastasis using a genetically induced cancer model, we crossed MT1-MMP-deficient mice to MMTV-polyoma virus middle T-antigen (PyMT) mice. Expression of PyMT in the MT1-MMP-deficient background consistently resulted in hyperplasia of the mammary gland as seen in wild-type PyMT littermates. Following orthotopic transplantation of PyMT+ glands into the cleared mammary fat pad of syngeneic recipient mice, MT1-MMP-deficient tumors were palpable earlier than wild-type tumors. Moreover, MT1-MMP-deficient tumors grew to the experimental end point size quicker than control tumors, but demonstrated markedly reduced ability to metastasize to the lungs of recipient mice. Accordingly, MT1-MMP-deficient mice displayed an overall reduction in metastasis count of 50%. MT1-MMP was expressed solely in the stroma of PyMT-induced tumors and those metastatic nodules that formed in the lungs were devoid of MT1-MMP expression. Stromal fibroblasts isolated from MT1-MMP-deficient tumors did not degrade type I collagen suggesting that efficient dissemination of tumor cells is dependent on stromal cell remodeling of the tumor environment. The data demonstrate directly that MT1-MMP-mediated proteolysis by stromal cells is important in the metastatic process.

Effects of short-term vibration and hypoxia during high-intensity cycling exercise on circulating levels of angiogenic regulators in humans

This study aimed to investigate the biological response to hypoxia as a stimulus, as well as exercise- and vibration-induced shear stress, which is known to induce angiogenesis. Twelve male cyclists (27.8 ± 5.4 yr) participated in this study. Each subject completed four cycle training sessions under normal conditions (NC) without vibration, NC with vibration, normobaric hypoxic conditions (HC) without vibration, and HC with vibration. Each session lasted 90 min, and sessions were held at weekly intervals in a randomized order. Five blood samples (pretraining and 0 h post-, 0.5 h post-, 1 h post-, and 4 h posttraining) were taken from each subject at each training session. Hypoxia was induced by a normobaric hypoxic chamber with an altitude of 2,500 m. The mechanical forces (cycling with or without vibration) were induced by a cycling ergometer. The parameters VEGF, endostatin, and matrix metalloproteinases (MMPs) were analyzed using the ELISA method. VEGF showed a significant increase immediately after the exercise only with exogenously induced vibrations, as calculated with separate ANOVA analysis. Endostatin increased after training under all conditions. Western blot analysis was performed for the determination of endostatin corresponding to the 22-kDa cleavage product of collagen XVIII. This demonstrated elevated protein content for endostatin at 0 h postexercise. MMP-2 increased in three of the four training conditions. The exception was NC with vibration. MMP-9 reached its maximum level at 4 h postexercise. In conclusion, the results support the contention that mechanical stimuli differentially influence factors involved in the induction of angiogenesis. These findings may contribute to a broader understanding of angiogenesis.

Signal transduction mediated by endostatin directly modulates cellular function of lung cancer cells in vitro

Endostatin (ED) is a carboxyl-terminal fragment of collagen XVIII with strong antiangiogenic activity. ED has been considered as a highly specific inhibitor of endothelial cell proliferation and migration through interaction with its receptor on the surface of endothelial cells. Recently, direct antitumor effects of ED in colon cancer cells and head and neck squamous cell carcinoma cells has been reported. However, its effect on lung cancer cells has not been clarified. The purpose of the present study was to determine the effect of ED on in vitro lung cancer cell function and to identify its receptor on lung cancer cells. We revealed that alpha5 integrin is capable of being a functional ED receptor among several integrins that are expressed on murine lung cancer (Lewis lung cancer [LLC]) cells. We further demonstrated that the ED-integrin interaction modulates various in vitro biological functions of LLC cells as we revealed that immobilized ED helps in LLC cell adhesion and migration in an integrin-dependent manner. Furthermore, ED inhibited LLC cell proliferation and induced apoptosis. Interestingly, ED did not demonstrate any antiproliferative activity against the other murine lung cancer cell line, KLN205, that lacks alpha5 integrin but binds to immobilized ED through the beta1 integrin. In addition, the binding of ED to alpha5 integrin on LLC cells induced phosphorylation of focal adhesion kinase. Taken together, these results suggest that the interaction between ED and alpha5 integrin may play an important role in lung cancer cell function.

A single bout of exercise activates matrix metalloproteinase in human skeletal muscle

The aims of this study were 1) to characterize changes in matrix metalloproteinase (MMP), endostatin, and vascular endothelial growth factor (VEGF)-A expression in skeletal muscle in response to a single bout of exercise in humans; and 2) to determine if any exchange of endostatin and VEGF-A between circulation and the exercising leg is associated with a change in the tissue expression or plasma concentration of these factors. Ten healthy males performed 65 min of cycle exercise, and muscle biopsies were obtained from the vastus lateralis muscle at rest and immediately and 120 min after exercise. In the muscle biopsies, measurements of mRNA expression levels of MMP-2, MMP-9, MMP-14, and tissue inhibitor of metalloproteinase; VEGF and endostatin protein levels; and MMP activities were performed. Femoral arterial and venous concentrations of VEGF-A and endostatin were determined before, during, and 120 min after exercise. A single bout of exercise increased MMP-9 mRNA and activated MMP-9 protein in skeletal muscle. No measurable increase of endostatin was observed in the skeletal muscle or in plasma following exercise. A concurrent increase in skeletal muscle VEGF-A mRNA and protein levels was induced by exercise, with no signs of peripheral uptake from the circulation. However, a decrease in plasma VEGF-A concentration occurred following exercise. Thus 1) a single bout of exercise activated the MMP system without any resulting change in tissue endostatin protein levels, and 2) the increased VEGF-A protein levels are due to changes in the skeletal muscle tissue itself. Other mechanisms are responsible for the observed exercise-induced decrease in VEGF-A in plasma.

Matrix metalloproteinases in human choroidal neovascular membranes excised following verteporfin photodynamic therapy

AIM

To evaluate expression of proangiogenic matrix metalloproteinases (MMP) 2 and 9 at distinct intervals after verteporfin photodynamic therapy (PDT) in human choroidal neovascular membranes (CNV) secondary to age-related macular degeneration (AMD).

METHODS

Retrospective review of an interventional case series of 49 patients who underwent removal of CNV. Twenty-six patients were treated with PDT 3 to 383 days prior to surgery. Twenty-three CNV without previous treatment were used as controls. CNV were stained for CD34, cytokeratin 18, endostatin, MMP-2 and MMP-9 by immunohistochemistry.

RESULTS

CNV without previous therapy disclosed MMP-2, MMP-9 in RPE-Bruch's membrane, vessels and stroma in different intensities. Three days after PDT, MMP-9 expression was significantly weaker in stroma (p = 0.0019). Endostatin was significantly reduced in vessels (p<0.001). At longer post-PDT intervals, a significant increase of MMP-9 in stroma (p = 0.037) and of endostatin in RPE-Bruch's membrane (p = 0.02), vessels (p = 0.005) and stroma (p<0.001) were disclosed. No significant changes in MMP-2 expression were detected.

CONCLUSIONS

PDT induced an early, temporary decrease in MMP-9 and endostatin expression. At longer intervals, MMP-9 increase is possibly associated with the angiogenic process responsible for recurrence after PDT. MMP-9, however, acts as a double-edged sword by concomitant induction of endostatin, an endogenous inhibitor of angiogenesis.

Early increase in serum levels of the angiogenesis-inhibitor endostatin and of basic fibroblast growth factor in melanoma patients during disease progression

BACKGROUND

Increased serum levels of angiogenesis-related factors such as endostatin, vascular endothelial cell growth factor (VEGF) or basic fibroblast growth factor (bFGF) have been demonstrated for a variety of solid and nonsolid tumours. Therefore, these factors have been suggested as diagnostic and in some studies as prognostic tumour markers.

OBJECTIVES

The purpose of the present study was to investigate a possible correlation of endostatin, VEGF or bFGF serum levels with disease progression in melanoma. Especially, we compared these factors to the established melanoma marker S-100 B, which increases in advanced disease but often fails to indicate early metastatic spread to regional lymph nodes.

PATIENTS AND METHODS

Sera from 197 melanoma patients and 35 healthy controls were measured by enzyme-linked immunosorbent assay; 72 patients had primary tumours (American Joint Committee on Cancer stages I and II), 55 had regional lymph node metastasis (stage III) and 70 patients had distant organ metastasis (stage IV).

RESULTS

Endostatin, VEGF and bFGF serum levels were significantly elevated in stage IV disease, compared with the control group. In stage III, endostatin and bFGF, but not VEGF or S-100 B, were significantly increased. However, follow-up of this patient group did not show a correlation with the future clinical course including time until progression or overall survival, arguing against a role of endostatin, VEGF or bFGF as prognostic markers.

CONCLUSIONS

These data indicate that endostatin or bFGF might be useful as diagnostic markers for the early detection of locoregional metastasis.

Endostatin: Current concepts about its biological role and mechanisms of action

Endogenous inhibitors of angiogenesis are proved to be a major factor preventing the emergence of clinically manifested stages of human cancer. The protein endostatin, a 20-kD proteolytic fragment of type XVIII collagen, is one of the most active natural inhibitors of angiogenesis. Endostatin specifically inhibits the in vitro and in vivo proliferation of endothelial cells, inducing their apoptosis through inhibition of cyclin D1. On the surface of endothelial cells, endostatin binds with the integrin alpha(5)beta(1) that activates the Src-kinase pathway. The binding of endostatin with integrins also down-regulates the activity of RhoA GTPase and inhibits signaling pathways mediated by small kinases of the Ras and Raf families. All these events promote disassembly of the actin cytoskeleton, disorders in cell-matrix interactions, and decrease in endotheliocyte mobility, i.e., promote the suppression of angiogenesis. Endostatin displays a high antitumor activity in vivo: it inhibits the progression of more than 60 types of tumors. This review summarizes results of numerous studies concerning the biological activity and action mechanism of endostatin.

Effect of verteporfin photodynamic therapy on endostatin and angiogenesis in human choroidal neovascular membranes

AIM

To evaluate the effect of verteporfin photodynamic therapy (PDT) on endostatin with regard to expression of vascular endothelial growth factor (VEGF) in human choroidal neovascular membranes (CNVs) secondary to age-related macular degeneration.

METHODS

A retrospective review of an interventional case series of 68 patients who underwent removal of CNV. 29 patients were treated with PDT 3-655 days before surgery. 39 CNVs without previous treatment were used as controls. CNVs were stained for CD34, CD105, Ki-67, cytokeratin 18, endostatin, E-selectin and VEGF. "Predominance score of VEGF over endostatin" (mean) was defined as the difference between VEGF and endostatin staining scores.

RESULTS

In four CNVs treated by PDT 3 days previously, PS was significantly higher in the retinal pigment epithelium (mean = 2.5, p = 0.006) and stroma (mean = 2, p = 0.015) than in the control group (mean = 0). At longer post-PDT intervals, PS was significantly decreased in the retinal pigment epithelium (mean = 0, p = 0.019) and stroma (mean = 0, p = 0.015). Proliferative activity was high (p = 0.023), but mostly related to inflammatory cells. PDT did not influence E-selectin expression significantly.

CONCLUSIONS

VEGF predominance over endostatin early after PDT might contribute to enhanced angiogenic activity associated with recurrences. Strategies upregulating or replacing endostatin early after PDT might increase the effectiveness of PDT.

Phase II study of recombinant human endostatin in patients with advanced neuroendocrine tumors

PURPOSE

Endostatin is a 20-kd proteolytic fragment of collagen XVIII that, in preclinical studies, has been shown to have antiangiogenic and antitumor activity. Both preclinical and human phase I studies of recombinant human endostatin (rhEndostatin) suggested activity in neuroendocrine tumors, which are known to be hypervascular. We therefore performed a multicenter phase II study of rhEndostatin in patients with carcinoid or pancreatic neuroendocrine tumors.

PATIENTS AND METHODS

Forty-two patients with advanced pancreatic endocrine tumors or carcinoid tumors were treated with rhEndostatin administered as a bid subcutaneous injection at a starting dose of 60 mg/m2/d. Steady-state trough levels were obtained after 6 weeks of therapy; patients who did not achieve a target therapeutic level of 300 ng/mL underwent dose escalation to 90 mg/m2/d. Patients were observed for evidence of toxicity, response, and survival.

RESULTS

rhEndostatin was associated with minimal toxicity. However, among 40 patients assessable for radiologic response, none experienced partial response to therapy, as defined by WHO criteria. The median steady-state trough level achieved after dose escalation was 331 ng/mL, within the postulated therapeutic range.

CONCLUSION

Treatment with rhEndostatin did not result in significant tumor regression in patients with advanced neuroendocrine tumors.