Endogenous angiogenesis inhibitor vasohibin1 exhibits broad-spectrum antilymphangiogenic activity and suppresses lymph node metastasis

m6A methylation-mediated regulation of LncRNA MEG3 suppresses ovarian cancer progression through miR-885-5p and the VASH1 pathway

BACKGROUND

Ovarian cancer poses a serious threat to women's health. Due to the difficulty of early detection, most patients are diagnosed with advanced-stage disease or peritoneal metastasis. We found that LncRNA MEG3 is a novel tumor suppressor, but its role in tumor occurrence and development is still unclear.

METHODS

We investigated the expression level of MEG3 in pan-cancer through bioinformatics analysis, especially in gynecological tumors. Function assays were used to detect the effect of MEG3 on the malignant phenotype of ovarian cancer. RIP, RNA pull-down, MeRIP-qPCR, actinomycin D test were carried out to explore the m6A methylation-mediated regulation on MEG3. Luciferase reporter gene assay, PCR and Western blot were implemented to reveal the potential mechanism of MEG3. We further confirmed the influence of MEG3 on tumor growth in vivo by orthotopic xenograft models and IHC assay.

RESULTS

In this study, we discovered that MEG3 was downregulated in various cancers, with the most apparent downregulation in ovarian cancer. MEG3 inhibited the proliferation, migration, and invasion of ovarian cancer cells. Overexpression of MEG3 suppressed the degradation of VASH1 by negatively regulating miR-885-5p, inhibiting the ovarian cancer malignant phenotype. Furthermore, we demonstrated that MEG3 was regulated at the posttranscriptional level. YTHDF2 facilitated MEG3 decay by recognizing METTL3‑mediated m6A modification. Compared with those injected with vector control cells, mice injected with MEG3 knockdown cells showed larger tumor volumes and faster growth rates.

CONCLUSION

We demonstrated that MEG3 is influenced by METTL3/YTHDF2 methylation and restrains ovarian cancer proliferation and metastasis by binding miR-885-5p to increase VASH1 expression. MEG3 is expected to become a therapeutic target for ovarian cancer.

The novel role of lymphatic vessels in the pathogenesis of ocular diseases

Historically, the eye has been considered as an organ free of lymphatic vessels. In recent years, however, it became evident, that lymphatic vessels or lymphatic-like vessels contribute to several ocular pathologies at various peri- and intraocular locations. The aim of this review is to outline the pathogenetic role of ocular lymphatics, the respective molecular mechanisms and to discuss current and future therapeutic options based thereon. We will give an overview on the vascular anatomy of the healthy ocular surface and the molecular mechanisms contributing to corneal (lymph)angiogenic privilege. In addition, we present (i) current insights into the cellular and molecular mechanisms occurring during pathological neovascularization of the cornea triggered e.g. by inflammation or trauma, (ii) the role of lymphatic vessels in different ocular surface pathologies such as dry eye disease, corneal graft rejection, ocular graft versus host disease, allergy, and pterygium, (iii) the involvement of lymphatic vessels in ocular tumors and metastasis, and (iv) the novel role of the lymphatic-like structure of Schlemm's canal in glaucoma. Identification of the underlying molecular mechanisms and of novel modulators of lymphangiogenesis will contribute to the development of new therapeutic targets for the treatment of ocular diseases associated with pathological lymphangiogenesis in the future. The preclinical data presented here outline novel therapeutic concepts for promoting transplant survival, inhibiting metastasis of ocular tumors, reducing inflammation of the ocular surface, and treating glaucoma. Initial data from clinical trials suggest first success of novel treatment strategies to promote transplant survival based on pretransplant corneal lymphangioregression.

Mechanism of ELL-associated factor 2 and vasohibin 1 regulating invasion, migration, and angiogenesis in colorectal cancer

BACKGROUND

As a novel endogenous anti-angiogenic molecule, vasohibin 1 (VASH1) is not only expressed in tumor stroma, but also in tumor tissue. Moreover, studies have shown that VASH1 may be a prognostic marker in colorectal cancer (CRC). Knockdown of VASH1 enhanced transforming growth factor-β1 (TGF-β1)/Smad3 pathway activity and type I/III collagen production. Our previous findings suggest that ELL-associated factor 2 (EAF2) may play a tumor suppressor and protective role in the development and progression of CRC by regulating signal transducer and activator of transcription 3 (STAT3)/TGF-β1 signaling pathway. However, the functional role and mechanism of VASH1-mediated TGF-β1 related pathway in CRC has not been elucidated.

AIM

To investigate the expression of VASH1 in CRC and its correlation with the expression of EAF2. Furthermore, we studied the functional role and mechanism of VASH1 involved in the regulation and protection of EAF2 in CRC cells in vitro.

METHODS

We collected colorectal adenocarcinoma and corresponding adjacent tissues to investigate the clinical expression of EAF2 protein and VASH1 protein in patients with advanced CRC. Following, we investigated the effect and mechanism of EAF2 and VASH1 on the invasion, migration and angiogenesis of CRC cells in vitro using plasmid transfection.

RESULTS

Our findings indicated that EAF2 was down-regulated and VASH1 was up-regulated in advanced CRC tissue compared to normal colorectal tissue. Kaplan-Meier survival analysis showed that the higher EAF2 Level group and the lower VASH1 Level group had a higher survival rate. Overexpression of EAF2 might inhibit the activity of STAT3/TGF-β1 pathway by up-regulating the expression of VASH1, and then weaken the invasion, migration and angiogenesis of CRC cells.

CONCLUSION

This study suggests that EAF2 and VASH1 may serve as new diagnostic and prognostic markers for CRC, and provide a clinical basis for exploring new biomarkers for CRC. This study complements the mechanism of EAF2 in CRC cells, enriches the role and mechanism of CRC cell-derived VASH1, and provides a new possible subtype of CRC as a therapeutic target of STAT3/TGF-β1 pathway.

Tregs are involved in VEGFA/ VASH1-related angiogenesis pathway in ovarian cancer

Vasohibin1 (VASH1) is a kind of vasopressor, produced by negative feedback from vascular endothelial growth factor A (VEGFA). Anti-angiogenic therapy targeting VEGFA is currently the first-line treatment for advanced ovarian cancer (OC), but there are still many adverse effects. Regulatory T cells (Tregs) are the main lymphocytes mediating immune escape function in the tumor microenvironment (TME) and have been reported to influence the function of VEGFA. However, whether Tregs are associated with VASH1 and angiogenesis in TME in OC is unclear. We aimed to explore the relationship between angiogenesis and immunosuppression in the TME of OC. We validated the relationship between VEGFA, VASH1, and angiogenesis in ovarian cancer and their prognostic implications. The infiltration level of Tregs and its marker forkhead box protein 3 (FOXP3) were explored in relation to angiogenesis-related molecules. The results showed that VEGFA and VASH1 were associated with clinicopathological stage, microvessel density and poor prognosis of ovarian cancer. Both VEGFA and VASH1 expression were associated with angiogenic pathways and there was a positive correlation between VEGFA and VASH1 expression. Tregs correlated with angiogenesis-related molecules and indicated that high FOXP3 expression is harmful to the prognosis. Gene set enrichment analysis (GSEA) predicted that angiogenesis, IL6/JAK/STAT3 signaling, PI3K/AKT/mTOR signaling, TGF-β signaling, and TNF-α signaling via NF-κB may be common pathways for VEGFA, VASH1, and Tregs to be involved in the development of OC. These findings suggest that Tregs may be involved in the regulation of tumor angiogenesis through VEGFA and VASH1, providing new ideas for synergistic anti-angiogenic therapy and immunotherapy in OC.

Non-Invasive and Real-Time Monitoring of the Breast Cancer Metastasis Degree via Metabolomics

Breast cancer (BC) is a serious threat to women's health and metastasis is the major cause of BC-associated mortality. Various techniques are currently used to preoperatively describe the metastatic status of tumors, based on which a comprehensive treatment protocol was determined. However, accurately staging a tumor before surgery remains a challenge, which may lead to the miss of optimal treatment options. More severely, the failure to detect and remove occult micrometastases often causes tumor recurrences. There is an urgent need to develop a more precise and non-invasive strategy for the detection of the tumor metastasis in lymph nodes and distant organs. Based on the facts that tumor metastasis is closely related to the primary tumor microenvironment (TME) evolutions and that metabolomics profiling of the circulatory system can precisely reflect subtle changes within TME, we suppose whether metabolomic technology can be used to achieve non-invasive and real-time monitoring of BC metastatic status. In this study, the metastasis status of BC mouse models with different tumor-bearing times was firstly depicted to mimic clinical anatomic TNM staging system. Metabolomic profiling together with metastasis-related changes in TME among tumor-bearing mice with different metastatic status was conducted. A range of differential metabolites reflecting tumor metastatic states were screened and in vivo experiments proved that two main metastasis-driving factors in TME, TGF-β and hypoxia, were closely related to the regular changes of these metabolites. The differential metabolites level changes were also preliminarily confirmed in a limited number of clinical BC samples. Metabolite lysoPC (16:0) was found to be useful for clinical N stage diagnosis and the possible cause of its changes was analyzed by bioinformatics techniques.

Cystathionine β-synthase as novel endogenous regulator of lymphangiogenesis via modulating VEGF receptor 2 and 3

Lymphangiogenesis is a key player in several diseases such as tumor metastasis, obesity, and graft rejection. Endogenous regulation of lymphangiogenesis is only partly understood. Here we use the normally avascular cornea as a model to identify endogenous regulators of lymphangiogenesis. Quantitative trait locus analysis of a large low-lymphangiogenic BALB/cN x high-lymphangiogenic C57BL/6 N intercross and prioritization by whole-transcriptome sequencing identify a novel gene responsible for differences in lymphatic vessel architecture on chromosome 17, the cystathionine β-synthase (Cbs). Inhibition of CBS in lymphatic endothelial cells results in reduce proliferation, migration, altered tube-formation, and decrease expression of vascular endothelial growth factor (VEGF) receptor 2 (VEGF-R2) and VEGF-R3, but not their ligands VEGF-C and VEGF-D. Also in vivo inflammation-induced lymphangiogenesis is significantly reduce in C57BL/6 N mice after pharmacological inhibition of CBS. The results confirm CBS as a novel endogenous regulator of lymphangiogenesis acting via VEGF receptor 2 and 3-regulation and open new treatment avenues in diseases associated with pathologic lymphangiogenesis.

Tumor-derived extracellular vesicles: The metastatic organotropism drivers

The continuous growing, spreading, and metastasis of tumor cells depend on intercellular communication within cells resident in a tissue environment. Such communication is mediated through the secretion of particles from tumor cells and resident cells known as extracellular vesicles (EVs) within a microenvironment. EVs are a heterogeneous population of membranous vesicles released from tumor cells that transfer many types of active biomolecules to recipient cells and induce physiologic and phenotypic alterations in the tissue environment. Spreading the 'seeds' of metastasis needs the EVs that qualify the 'soil' at distant sites to promote the progress of arriving tumor cells. Growing evidence indicates that EVs have vital roles in tumorigenesis, including pre-metastatic niche formation and organotropic metastasis. These EVs mediate organotropic metastasis by modifying the pre-metastatic microenvironment through different pathways including induction of phenotypic alternation and differentiation of cells, enrolment of distinct supportive stromal cells, up-regulation of the expression of pro-inflammatory genes, and induction of immunosuppressive status. However, instead of pre-metastatic niche formation, evidence suggests that EVs may mediate reawakening of dormant niches. Findings regarding EVs function in tumor metastasis have led to growing interests in the interdisciplinary significance of EVs, including targeted therapy, cell-free therapy, drug-delivery system, and diagnostic biomarker. In this review, we discuss EVs-mediated pre-metastatic niche formation and organotropic metastasis in visceral such as lung, liver, brain, lymph node, and bone with a focus on associated signaling, causing visceral environment hospitable for metastatic cells. Furthermore, we present an overview of the possible therapeutic application of EVs in cancer management.

Vasohibin-1 and -2 in pulmonary lymphangioleiomyomatosis (LAM) cells associated with angiogenic and prognostic factors

Lymphangioleiomyomatosis (LAM) is a rare pulmonary neoplasm, clinically associated with dyspnea and respiratory failure. Current therapeutic modalities do not necessarily reach satisfactory outcome and novel therapeutic approaches are currently warranted. Therefore, in this study, we focused on vasohibin-1 (VASH1) and -2 (VASH2); VASH1 terminated and VASH2 promoted angiogenesis. In addition, both VASH1/2 were reported to influence the progression of various human malignancies. We first performed hierarchical clustering analysis to attempt to classify 36 LAM cases into three different clusters according to immunoreactivity of VASH1/2 and other angiogenic and prognostic factors of LAM; VEGFR1/2/3, p-mTOR, p-S6, p-4EBP, ERα, PgR, MMP2, and MMP9. The cluster harboring higher angiogenic factors had higher VASH1/2 status. VASH1 was significantly positively correlated with VEGFR2, MMP9, and p-mTOR (p-value <0.05), and VASH2 with both angiogenic and prognostic factors including VEGFR1, PgR, MMP9, p-mTOR, p-S6, and p-4EBP (p-value <0.05). Subsequent PCR array of angiogenic genes demonstrated that high VASH1 mRNA was significantly positively associated with the status of SPHK1 and TYPM, lower EGF and EFNB2 (p-value <0.05), and high VASH2 mRNA negatively with MMP2 (p-value <0.05). VASH1 was considered to be up-regulated by activation of angiogenesis, whereas VASH2 could influence the angiogenesis and progression of LAM.

Post-translational modifications of tubulin: their role in cancers and the regulation of signaling molecules

Microtubules play an important role in regulating several vital cellular activities, including cell division and tissue organization, through their dynamic protofilament network. In addition to forming the cytoskeleton, microtubules regulate the intracellular trafficking of cytoplasmic components and various signaling molecules, depending on the presence of post-transitional modifications (PTMs) and binding proteins. Accumulating evidence indicates the significant role of microtubule PTMs on cancer behavior. The PTMs that frequently occur on microtubules include acetylation, detyrosination, tyrosination, polyglutamylation, and polyglycylation. Alterations in these PTMs cause global effects on intracellular signal transduction, strongly linked to cancer pathogenesis. This review provides an update on the role of microtubule PTMs in cancer aggressiveness, particularly regarding cell death, sensitivity to chemotherapy, cell migration, and invasion. Additionally, it provides a mechanistic explanation of the molecular signaling pathways involved. This information might prove useful for predictive or therapeutic purposes.

circASS1 overexpression inhibits the proliferation, invasion and migration of colorectal cancer cells by regulating the miR-1269a/VASH1 axis

Colorectal cancer (CRC), the third most common cancer worldwide, poses a threat to human life. However, its underlying mechanism is unclear and no satisfactory treatment is available. The present study aimed to investigate the role of circular RNA argininosuccinate synthase 1 (circASS1) in CRC cells and tissues to identify the potential mechanism underlying the pathogenesis of CRC. The expression of circASS1 in CRC cells and tissues was determined by reverse transcription-quantitative PCR. Following circASS1 overexpression in HT29 cells, cell viability, colony formation and apoptosis were measured using MTT, colony formation and TUNEL assays, respectively. Cell invasion and migration were also assessed. After confirming the associations among circASS1, microRNA (miR)-1269a and vasohibin 1 (VASH1), the characteristics of the HT29 cell line were assessed by performing the aforementioned assays. circASS1 expression was decreased in CRC cells and tissues, and circASS1 overexpression suppressed CRC cell proliferation, invasion and migration. circASS1 adsorbed miR-1269a and regulated its expression, and VASH1 was a target protein of miR-1269a. circASS1 overexpression decreased cell proliferation, invasion and migration, but enhanced cell apoptosis in HT29 cells, which was reversed by co-transfection with miR-1269a mimic or short hairpin RNA-VASH1. In conclusion, circASS1 overexpression inhibited CRC cell proliferation, invasion and migration by regulating miR-1269a/VASH1, which indicated a potential molecular mechanism underlying the pathogenesis of CRC.

Extracellular vesicles in the development of organ-specific metastasis

Distant organ metastasis, often termed as organotropic metastasis or metastatic organotropism, is a fundamental feature of malignant tumours and accounts for most cancer-related mortalities. This process is orchestrated by many complex biological interactions and processes that are mediated by a combination of anatomical, genetic, pathophysiological and biochemical factors. Recently, extracellular vesicles (EVs) are increasingly being demonstrated as critical mediators of bi-directional tumour-host cell interactions, controlling organ-specific infiltration, adaptation and colonization at the secondary site. EVs govern organotropic metastasis by modulating the pre-metastatic microenvironment through upregulation of pro-inflammatory gene expression and immunosuppressive cytokine secretion, induction of phenotype-specific differentiation and recruitment of specific stromal cell types. This review discusses EV-mediated metastatic organotropism in visceral (brain, lung, liver, and lymph node) and skeletal (bone) metastasis, and discusses how the pre-metastatic education by EVs transforms the organ into a hospitable, tumour cell-friendly milieu that supports the growth of metastatic cells. Decoding the organ-specific traits of EVs and their functions in organotropic metastasis is essential in accelerating the clinical application of EVs in cancer management.

Pathophysiology of decompensated cirrhosis: Portal hypertension, circulatory dysfunction, inflammation, metabolism and mitochondrial dysfunction

Patients with acutely decompensated cirrhosis have a dismal prognosis and frequently progress to acute-on-chronic liver failure, which is characterised by hepatic and extrahepatic organ failure(s). The pathomechanisms involved in decompensation and disease progression are still not well understood, and as specific disease-modifying treatments do not exist, research to identify novel therapeutic targets is of the utmost importance. This review amalgamates the latest knowledge on disease mechanisms that lead to tissue injury and extrahepatic organ failure - such as systemic inflammation, mitochondrial dysfunction, oxidative stress and metabolic changes - and marries these with the classical paradigms of acute decompensation to form a single paradigm. With this detailed breakdown of pathomechanisms, we identify areas for future research. Novel disease-modifying strategies that break the vicious cycle are urgently required to improve patient outcomes.

Vasohibin 1 selectively regulates secondary sprouting and lymphangiogenesis in the zebrafish trunk

Previous studies have shown that Vasohibin 1 (Vash1) is stimulated by VEGFs in endothelial cells and that its overexpression interferes with angiogenesis in vivo Recently, Vash1 was found to mediate tubulin detyrosination, a post-translational modification that is implicated in many cell functions, such as cell division. Here, we used the zebrafish embryo to investigate the cellular and subcellular mechanisms of Vash1 on endothelial microtubules during formation of the trunk vasculature. We show that microtubules within venous-derived secondary sprouts are strongly and selectively detyrosinated in comparison with other endothelial cells, and that this difference is lost upon vash1 knockdown. Vash1 depletion in zebrafish specifically affected secondary sprouting from the posterior cardinal vein, increasing endothelial cell divisions and cell number in the sprouts. We show that altering secondary sprout numbers and structure upon Vash1 depletion leads to defective lymphatic vessel formation and ectopic lymphatic progenitor specification in the zebrafish trunk.

Bioluminescence Imaging Applications in Cancer: A Comprehensive Review

Bioluminescence imaging (BLI), an optical preclinical imaging modality, is an invaluable imaging modality due to its low-cost, high throughput, fast acquisition times, and functional imaging capabilities. BLI is being extensively used in the field of cancer imaging, especially with the recent developments in genetic-engineering, stem cell, and gene therapy treatments. The purpose of this paper is to provide a comprehensive review of the principles, developments, and current status of BLI in cancer research. This paper covers the fundamental BLI concepts including BLI reporters and enzyme-substrate systems, data acquisition, and image characteristics. It reviews the studies discussing the use of BLI in cancer research such as imaging tumor-characteristic phenomena including tumorigenesis, metastasis, cancer metabolism, apoptosis, hypoxia, and angiogenesis, and response to cancer therapy treatments including chemotherapy, radiotherapy, immunotherapy, gene therapy, and stem cell therapy. The key advantages and disadvantages of BLI compared to other common imaging modalities are also discussed.

The Tubulin Code in Mitosis and Cancer

The “tubulin code” combines different α/β-tubulin isotypes with several post-translational modifications (PTMs) to generate microtubule diversity in cells. During cell division, specific microtubule populations in the mitotic spindle are differentially modified, but only recently, the functional significance of the tubulin code, with particular emphasis on the role specified by tubulin PTMs, started to be elucidated. This is the case of α-tubulin detyrosination, which was shown to guide chromosomes during congression to the metaphase plate and allow the discrimination of mitotic errors, whose correction is required to prevent chromosomal instability—a hallmark of human cancers implicated in tumor evolution and metastasis. Although alterations in the expression of certain tubulin isotypes and associated PTMs have been reported in human cancers, it remains unclear whether and how the tubulin code has any functional implications for cancer cell properties. Here, we review the role of the tubulin code in chromosome segregation during mitosis and how it impacts cancer cell properties. In this context, we discuss the existence of an emerging “cancer tubulin code” and the respective implications for diagnostic, prognostic and therapeutic purposes.

Tubulin carboxypeptidase activity of vasohibin-1 inhibits angiogenesis by interfering with endocytosis and trafficking of pro-angiogenic factor receptors

Receptor endocytosis is crucial for integrating extracellular stimuli of pro-angiogenic factors, including vascular endothelial growth factor (VEGF), into the cell via signal transduction. VEGF not only triggers various angiogenic events including endothelial cell (EC) migration, but also induces the expression of negative regulators of angiogenesis, including vasohibin-1 (VASH1). While we have previously reported that VASH1 inhibits angiogenesis in vitro and in vivo, its mode of action on EC behavior remains elusive. Recently VASH1 was shown to have tubulin carboxypeptidase (TCP) activity, mediating the post-translational modification of microtubules (MTs) by detyrosination of α-tubulin within cells. However, the role of VASH1 TCP activity in angiogenesis has not yet been clarified. Here, we showed that VASH1 detyrosinated α-tubulin in ECs and suppressed in vitro and in vivo angiogenesis. In cultured ECs, VASH1 impaired endocytosis and trafficking of VEGF receptor 2 (VEGFR2), which resulted in the decreased signal transduction and EC migration. These effects of VASH1 could be restored by tubulin tyrosine ligase (TTL) in ECs, suggesting that detyrosination of α-tubulin negatively regulates angiogenesis. Furthermore, we found that detyrosinated tubulin-rich MTs were not adequate as trafficking rails for VEGFR2 endocytosis. Consistent with these results, inhibition of TCP activity of VASH1 led to the inhibition of VASH1-mediated suppression of VEGF-induced signals, EC migration, and in vivo angiogenesis. Our results indicate a novel mechanism of VASH1-mediated inhibition of pro-angiogenic factor receptor trafficking via modification of MTs.

Plasma vasohibin-1 and vasohibin-2 are useful biomarkers in patients with esophageal squamous cell carcinoma

BACKGROUND

Vasohibins (VASH), which are angiogenesis regulators, consist of Vasohibin-1 (VASH1) and Vasohibin-2 (VASH2). VASH1 is an angiogenesis inhibitor, while VASH2 is a proangiogenic factor. Patients with esophageal squamous cell carcinoma (ESCC) with high tumor expression levels of VASH1 and VASH2 have been reported to show a poor prognosis. The clinical significance of VASH concentrations in the blood of patients with ESCC has not yet been investigated.

METHODS

Plasma samples from 89 patients with ESCC were analyzed, and the relationships between the plasma VASH concentrations and the clinicopathological factors of the patients were evaluated. Immunohistochemical examination (IHC) of the resected tumor specimens for VASH was performed in 56 patients, and the correlation between the plasma VASH concentrations and tumor expression levels of VASH was analyzed.

RESULTS

The patient group with high plasma concentrations of VASH1 showed a higher frequency of lymph node metastasis (P = 0.01) and an invasive growth pattern (P = 0.05). Furthermore, poorly differentiated cancer occurred at a higher frequency in the patient group with high plasma concentrations of VASH2 (P < 0.01). High tumor expression levels of VASH1 were encountered more frequently in the patient group with high plasma concentrations of VASH1 (P = 0.03), and high tumor expression levels of VASH2 were encountered more frequently in the patient group with high plasma concentrations of VASH2 (P = 0.04).

CONCLUSIONS

In patients with ESCC, high plasma concentrations were associated with poor clinical outcomes for both VASH1 and VASH2. We propose that results indicate that plasma VASH1 and VASH2 are useful biomarkers in patients with ESCC.

A review on vasohibin and ocular neovascularization

Ischemic and neovascular disease is one of the most difficult ocular diseases to deal with nowadays. Redundancy, poor visual acuity and decreased life quality are bothering patients and ophthalmologists for decades. After vascular endothelial growth factor (VEGF) was found to be a primary factor in promoting retinal angiogenesis, intravitreal injection of anti-VEGF drugs has been the first-line treatment. Whereas, some patients are refractory to this therapy and problems of economic burden, local complications and adverse effects promote researches into other possible targets. The vasohibin (VASH) family is a newly-investigated factor in modulating ocular angiogenesis. The family includes VASH1 and VASH2, which show opposite effects of inhibiting and accelerating angiogenesis respectively. Positive results have been reported in cellular and animal experiments. With further researches, it can be a promising future target of treating ocular neovascular diseases.

Immunomodulatory Strategies Targeting Dendritic Cells to Improve Corneal Graft Survival

Even though the cornea is regarded as an immune-privileged tissue, transplantation always comes with the risk of rejection due to mismatches between donor and recipient. It is common sense that an alternative to corticosteroids as the current gold standard for treatment of corneal transplantation is needed. Since blood and lymphatic vessels have been identified as a severe risk factor for corneal allograft survival, much research has focused on vessel regression or inhibition of hem- and lymphangiogenesis in general. However, lymphatic vessels have been identified as required for the inflammation's resolution. Therefore, targeting other players of corneal engraftment could reveal new therapeutic strategies. The establishment of a tolerogenic microenvironment at the graft site would leave the recipient with the ability to manage pathogenic conditions independent from transplantation. Dendritic cells (DCs) as the central player of the immune system represent a target that allows the induction of tolerogenic mechanisms by many different strategies. These strategies are reviewed in this article with regard to their success in corneal transplantation.

Role of Endogenous Regulators of Hem- And Lymphangiogenesis in Corneal Transplantation

Under normal conditions, the cornea, being the transparent “windscreen” of the eye, is free of both blood and lymphatic vessels. However, various diseases of the eye, like infections, can interfere with the balance between promoting and inhibiting factors, which leads to ingrowth of blood and lymphatic vessels. The newly formed lymphatic vessels increase the risk of graft rejection after subsequent corneal transplantation. Corneal transplantation is one of the most commonly performed transplantations worldwide, with more than 40,000 surgeries per year in Europe. To date, various anti-hem- and anti-lymphangiogenic treatment strategies have been developed specifically for the corneal vascular endothelial growth factor (VEGF) pathway. Currently, however, no treatment strategies are clinically available to specifically modulate lymphangiogenesis. In this review, we will give an overview about endogenous regulators of hem- and lymphangiogenesis and discuss potential new strategies for targeting pathological lymphangiogenesis. Furthermore, we will review recently identified modulators and demonstrate that the cornea is a suitable model for the identification of novel endogenous modulators of lymphangiogenesis. The identification of novel modulators of lymphangiogenesis and a better understanding of the signaling pathways involved will contribute to the development of new therapeutic targets for the treatment of pathological lymphangiogenesis. This, in turn, will improve graft rejection, not only for the cornea.

Immune reactions after modern lamellar (DALK, DSAEK, DMEK) versus conventional penetrating corneal transplantation

In the past decade, novel lamellar keratoplasty techniques such as Deep Anterior Lamellar Keratoplasty (DALK) for anterior keratoplasty and Descemet stripping automated endothelial keratoplasty (DSAEK)/Descemet membrane endothelial keratoplasty (DMEK) for posterior keratoplasty have been developed. DALK eliminates the possibility of endothelial allograft rejection, which is the main reason for graft failure after penetrating keratoplasty (PK). Compared to PK, the risk of endothelial graft rejection is significantly reduced after DSAEK/DMEK. Thus, with modern lamellar techniques, the clinical problem of endothelial graft rejection seems to be nearly solved in the low-risk situation. However, even with lamellar grafts there are epithelial, subepithelial and stromal immune reactions in DALK and endothelial immune reactions in DSAEK/DMEK, and not all keratoplasties can be performed in a lamellar fashion. Therefore, endothelial graft rejection in PK is still highly relevant, especially in the "high-risk" setting, where the cornea's (lymph)angiogenic and immune privilege is lost due to severe inflammation and pathological neovascularization. For these eyes, currently available treatment options are still unsatisfactory. In this review, we will describe currently used keratoplasty techniques, namely PK, DALK, DSAEK, and DMEK. We will summarize their indications, provide surgical descriptions, and comment on their complications and outcomes. Furthermore, we will give an overview on corneal transplant immunology. A specific focus will be placed on endothelial graft rejection and we will report on its incidence, clinical presentation, and current/future treatment and prevention options. Finally, we will speculate how the field of keratoplasty and prevention of corneal allograft rejection will develop in the future.

Natural Selection Footprints Among African Chicken Breeds and Village Ecotypes

Natural selection is likely a major factor in shaping genomic variation of the African indigenous rural chicken, driving the development of genetic footprints. Selection footprints are expected to be associated with adaptation to locally prevailing environmental stressors, which may include diverse factors as high altitude, disease resistance, poor nutrition, oxidative and heat stresses. To determine the existence of a selection footprint, 268 birds were randomly sampled from three indigenous ecotypes from East Africa (Rwanda and Uganda) and North Africa (Baladi), and two registered Egyptian breeds (Dandarawi and Fayoumi). Samples were genotyped using the chicken Affymetrix 600K Axiom^® Array. A total of 494,332 SNPs were utilized in the downstream analysis after implementing quality control measures. The intra-population runs of homozygosity (ROH) that occurred in >50% of individuals of an ecotype or in >75% of a breed were studied. To identify inter-population differentiation due to genetic structure, F_ST was calculated for North- vs. East-African populations and Baladi and Fayoumi vs. Dandarawi for overlapping windows (500 kb with a step-size of 250 kb). The ROH and F_ST mapping detected several selective sweeps on different autosomes. Results reflected selection footprints of the environmental stresses, breed behavior, and management. Intra-population ROH of the Egyptian chickens showed selection footprints bearing genes for adaptation to heat, solar radiation, ion transport and immunity. The high-altitude-adapted East-African populations' ROH showed a selection signature with genes for angiogenesis, oxygen-heme binding and transport. The neuroglobin gene (GO:0019825 and GO:0015671) was detected on a Chromosome 5 ROH of Rwanda-Uganda ecotypes. The sodium-dependent noradrenaline transporter, SLC6A2 on a Chromosome 11 ROH in Fayoumi breed may reflect its active behavior. Inter-population F_ST among Egyptian populations reflected genetic mechanisms for the Fayoumi resistance to Newcastle Disease Virus (NDV), while F_ST between Egyptian and Rwanda-Uganda populations indicated the Secreted frizzled related protein 2, SFRP2, (GO:0009314) on Chromosome 4, that contributes to melanogenic activity and most likely enhances the Dandarawi chicken adaptation to high-intensity of solar radiation in Southern Egypt. These results enhance our understanding of the natural selection forces role in shaping genomic structure for adaptation to the stressful African conditions.

Arterial Lymphatics in Atherosclerosis: Old Questions, New Insights, and Remaining Challenges

The lymphatic network is well known for its role in the maintenance of tissue fluid homeostasis, absorption of dietary lipids, trafficking of immune cells, and adaptive immunity. Aberrant lymphatic function has been linked to lymphedema and immune disorders for a long time. Discovery of lymphatic cell markers, novel insights into developmental and postnatal lymphangiogenesis, development of genetic mouse models, and the introduction of new imaging techniques have improved our understanding of lymphatic function in both health and disease, especially in the last decade. Previous studies linked the lymphatic vasculature to atherosclerosis through regulation of immune responses, reverse cholesterol transport, and inflammation. Despite extensive research, many aspects of the lymphatic circulation in atherosclerosis are still unknown and future studies are required to confirm that arterial lymphangiogenesis truly represents a therapeutic target in patients with cardiovascular disease. In this review article, we provide an overview of factors and mechanisms that regulate lymphangiogenesis, summarize recent findings on the role of lymphatics in macrophage reverse cholesterol transport, immune cell trafficking and pathogenesis of atherosclerosis, and present an overview of pharmacological and genetic strategies to modulate lymphatic vessel density in cardiovascular tissue.

The correlation of the expressions of WWOX, LGR5 and vasohibin-1 in epithelial ovarian cancer and their clinical significance

BACKGROUND

Recurrence and metastasis are the most common reasons for the treatment failure of epithelial ovarian carcinoma (EOC). WW domain-containing oxidoreductase (WWOX) is a tumor suppressor, which causes down- or lost-expression and is able to promote cell infiltration and progression in several human malignant tumors. Leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5), an important marker of cancer stem cells (CSCs), has been considered a useful biomarker of tumor metastasis and patient prognosis. Vasohibin-1 (VASH1), also known as angiogenesis inhibiting protein-1, can be used as a biological marker for early infiltration and metastasis in many cancers. However, the correlations of WWOX, LGR5, and vasohibin-1 in EOC are still unclear. In this study, we analyzed the relationships of these three markers, as well as their respective correlations with clinicopathological characteristics, to determine whether they are useful biomarkers for the improvement and prognosis of EOC patients.

METHODS

The positive rates of WWOX, LGR5, and vasohibin-1 in 210 whole tissue samples of EOC were detected by immunohistochemistry. Clinical data was also collected.

RESULTS

The expressions of LGR5 and vasohibin-1 were significantly higher in EOC tissues than the levels in benign ovary tumors. However, WWOX expression was significantly lower in EOC tissues than the levels in benign ovary tumors. The investigation of the associations between WWOX, or LGR5, or vasohibin-1 positive rates with the clinicopathological characteristics of EOC showed associations between the positive rates of each with grade of tumor, lymph node metastasis (LNM), implantation, and International Federation of Gynecology and Obstetrics (FIGO) stage. The overall survival (OS) time of patients with LGR5-positive or vasohibin-1-positive EOC tissues was significantly shorter than that of those who were negative. On the contrary, the OS time of patients with WWOX-positive EOC tissues was significantly higher than the OS time of those who were negative. Importantly, a multivariate analysis indicated that the high level of WWOX, LGR5, and vasohibin-1, as well as implantation, LNM and FIGO stage could be independent prognostic biomarkers for OS in EOC patients.

CONCLUSIONS

The expressions of WWOX, LGR5, and vasohibin-1 may represent useful promising biomarkers for metastasis and prognosis, as well as potential therapeutic targets in EOC.

Tyrosinase Is a Novel Endogenous Regulator of Developmental and Inflammatory Lymphangiogenesis

Lymphangiogenesis is critically involved in tissue fluid balance, graft rejection, and tumor metastasis. Endogenous regulation of lymphangiogenesis is poorly understood. Herein, we use the lymphatic vessel architecture at the limbal border of the normally avascular cornea, a quantitative trait under strong genetic influence, as a model system to identify new candidate genes regulating lymphangiogenesis. Comparing low-lymphangiogenic BALB/cN with high-lymphangiogenic C57BL/6N mice, we performed quantitative trait loci analysis of five phenotypes in a large BALB/cN × C57BL/6N intercross (n = 795) and identified three to eight genome-wide significant loci, the strongest on chromosome 7 containing tyrosinase (Tyr). Tyrosinase-negative mice showed significantly increased limbal lymph vascularized areas, a higher number of lymphatic vessel end points, and branching points and increased inflammation-induced lymphangiogenesis. These findings confirm that tyrosinase is a novel lymphangiogenesis regulator in developmental and inflammatory lymphangiogenesis. Our findings link melanin synthesis with lymphangiogenesis and open new treatment options in lymphangiogenesis-related diseases.

Cervical squamous cell carcinoma-secreted exosomal miR-221-3p promotes lymphangiogenesis and lymphatic metastasis by targeting VASH1

Cancer-secreted exosomal miRNAs are emerging mediators of cancer-stromal cross-talk in the tumor environment. Our previous miRNAs array of cervical squamous cell carcinoma (CSCC) clinical specimens identified upregulation of miR-221-3p. Here, we show that miR-221-3p is closely correlated with peritumoral lymphangiogenesis and lymph node (LN) metastasis in CSCC. More importantly, miR-221-3p is characteristically enriched in and transferred by CSCC-secreted exosomes into human lymphatic endothelial cells (HLECs) to promote HLECs migration and tube formation in vitro, and facilitate lymphangiogenesis and LN metastasis in vivo according to both gain-of-function and loss-of-function experiments. Furthermore, we identify vasohibin-1 (VASH1) as a novel direct target of miR-221-3p through bioinformatic target prediction and luciferase reporter assay. Re-expression and knockdown of VASH1 could respectively rescue and simulate the effects induced by exosomal miR-221-3p. Importantly, the miR-221-3p-VASH1 axis activates the ERK/AKT pathway in HLECs independent of VEGF-C. Finally, circulating exosomal miR-221-3p levels also have biological function in promoting HLECs sprouting in vitro and are closely associated with tumor miR-221-3p expression, lymphatic VASH1 expression, lymphangiogenesis, and LN metastasis in CSCC patients. In conclusion, CSCC-secreted exosomal miR-221-3p transfers into HLECs to promote lymphangiogenesis and lymphatic metastasis via downregulation of VASH1 and may represent a novel diagnostic biomarker and therapeutic target for metastatic CSCC patients in early stages.

High preoperative plasma vasohibin-1 concentration predicts better prognosis in patients with non-small cell lung carcinoma

BACKGROUND AND AIM

Vasohibin-1 (VASH1) is an angiogenesis inhibitor synthesized and secreted by endothelial cells, whose expression is induced by angiogenic stimuli such as vascular endothelial growth factor. We have previously demonstrated that VASH1 is immunohistochemically evident in endothelial cells in the tumor microenvironment of patients with non-small cell lung cancer (NSCLC) and is positively correlated with that of vascular endothelial growth factor in cancer cells. Here, we determined the preoperative plasma concentration of VASH1 in patients with NSCLC and evaluated the association between the preoperative VASH1 levels and certain outcomes.

METHODS

We analyzed presurgical plasma VASH1 concentrations in a total of 79 lung cancer patients (51 males and 28 females; 34-83 y of age; 46 adenocarcinomas, 27 squamous cell carcinomas, and 6 other types) who underwent lung resection. The impact of preoperative VASH1 level was analyzed using clinical characteristics and prognosis.

RESULTS

Plasma VASH1 concentration ranged from 34.1 to 1190.4 fmol/mL. We divided the patients into 3 groups according to plasma VASH1 level for this assessment: low VASH1 group (n = 26), medium VASH1 group (n = 27), and high VASH1 group (n = 26). The death and recurrence rates of the high, medium, and low VASH1 groups were 5.5, 16.2, and 12.7 per 100 person-years, respectively. Multivariate adjusted hazard ratio of death and recurrence of the high VASH1 group was lower than that of the low VASH1 group (hazard ratio 0.42; 95% CI 0.17-0.99).

CONCLUSION

The present analysis suggests that high preoperative plasma VASH1 concentration is associated with better prognosis in patients with NSCLC. We propose preoperative VASH1 level as a biomarker for the prognosis of patients with non-small cell lung carcinoma.

Induced dural lymphangiogenesis facilities soluble amyloid-beta clearance from brain in a transgenic mouse model of Alzheimer's disease

Impaired amyloid-β clearance from the brain is a core pathological event in Alzheimer's disease. The therapeutic effect of current pharmacotherapies is unsatisfactory, and some treatments cause severe side effects. The meningeal lymphatic vessels might be a new route for amyloid-β clearance. This study investigated whether promoting dural lymphangiogenesis facilitated the clearance of amyloid-β from the brain.First, human lymphatic endothelial cells were treated with 100 ng/mL recombinant human vascular endothelial growth factor-C (rhVEGF-C) protein. Light microscopy verified that rhVEGF-C, a specific ligand for vascular endothelial growth factor receptor-3 (VEGFR-3), significantly promoted tube formation of human lymphatic endothelial cells in vitro. In an in vivo study, 200 μg/mL rhVEGF-C was injected into the cisterna magna of APP/PS1 transgenic mice, once every 2 days, four times in total. Immunofluorescence staining demonstrated high levels of dural lymphangiogenesis in Alzheimer's disease mice. One week after rhVEGF-C administration, enzyme-linked immunosorbent assay results showed that levels of soluble amyloid-β were decreased in cerebrospinal fluid and brain. The Morris water maze test demonstrated that spatial cognition was restored. These results indicate that the upregulation of dural lymphangiogenesis facilities amyloid-β clearance from the brain of APP/PS1 mice, suggesting the potential of the VEGF-C/VEGFR-3 signaling pathway as a therapeutic target for Alzheimer's disease.

The roles of vasohibin and its family members: Beyond angiogenesis modulators

Vasohibin-1 is an intrinsic angiogenesis inhibitor, and is expressed in endothelial cells via induction by pro-angiogenesis factors. It is known to inhibit several processes of angiogenesis, with different mechanisms from extrinsic angiogenesis inhibitors. Vasohibin-2 is mainly expressed by mononuclear cells which have been mobilized from bone marrow. It not only promotes angiogenesis, but also modulates the releases of FGF-2 and VEGF, which are the two major inducers for vasohibin1. Hypoxic environment induces the expression of hypoxia-inducible Factor 1α with a result of VEGF release nearly in all tumor cell lines and tissues. However, it has been observed that hypoxia reduces the inducible effects of VEGF on vasohibin, which indicates that a complicated mechanism exists in the angiogenesis. Vasohibin and its family members play important roles in both the physiological and pathological procedures, in contrary but complementary patterns. Furthermore, human aortic smooth muscle cells and fibroblast have also been detected to express vasohibin on a moderate to weak scale range. Recently, the results of an increasing number of studies in vivo have shown that vasohibin can also be detected in several cancers, and is associated with micro-vessel densities, histology grades, invasions, poor clinical features, metastasis, and dissemination in abdominal cavities, as well as EMT. In more recent reports, it has been confirmed that, along with being angiogenesis regulators, a variety of other roles have been associated with this family. The focus of this study was the upstream regulatory mechanisms of vasohibin expressions, and their role in regard to the downstream target proteins of vasohibin, especially in carcinoma. Vasohibin is considered to be an original angiogenesis inhibitor, and has a much broader significance in pathological processes. It can be taken as an independent prognostic factor, as well as a potential strategy for cancer therapy programs.

[Expression of vasohibin-1 and MACC1 in lung squamous cell carcinoma and their clinicopathological significance]

OBJECTIVE

To investigate the expressions of vasohibin-1 and MACC1 in lung squamous cell carcinoma (LSCC) and their associations with the clinicopathological characteristics of the patients.

METHODS

The expressions of vasohibin-1 and MACC1 proteins were examined with immunohistochemistry in 160 LSCC tissues and 80 normal lung tissues.

RESULTS

The positivity rates of vasohibin-1 and MACC1 proteins were 59.4% and 11.3% in LSCC tissues, respectively, which were significantly higher than the rates in normal lung tissues (57.5% and 8.8%, respectively; P<0.05). The expressions of vasohibin-1 and MACC1 proteins were significantly correlated with the tumor grades, lymph node metastasis, and TNM stages (all P<0.05). Spearman correlation analysis indicated a positive correlation between vasohibin-1 expression and MACC1 expressions (P<0.001). Kaplan-Meier survival analysis showed that LSCC patients with a positive expression of vasohibin-1 had significantly shorter overall survival time than those negative for vasohibin-1; the overall survival time was also significantly shorter in patients positive for MACC1 than in those negative for MACC1 (both P<0.05). Multivariate COX regression analysis indicated that positive expressions of vasohibin-1 and MACC1 protein and TNM stage were independent prognostic factors of LSCC.

CONCLUSION

Aberrant expressions of vasohibin-1 and MACC1 may participate in the development and promote invasion and metastasis of LSCC. The combined detection of vasohibin-1 and MACC1 expression may provide important evidence for predicting the progression and prognosis of LSCC.

MicroRNA-4530 promotes angiogenesis by targeting VASH1 in breast carcinoma cells

The results of our previous study revealed that microRNA (miRNA/miR)-4530 was upregulated in the serum of patients with diabetic retinopathy. The TargetScan miRNA database was used to identify potential targets of miR-4530 and vasohibin-1 (VASH1) was predicted as one of the targets. The results of our previous study demonstrated that miR-4530 was able to promote angiogenesis in human umbilical vein endothelial cells. Therefore, suppressing miR-4530 may be a potentially novel approach towards inhibiting tumor angiogenesis. The present study aimed to investigate the function of miR-4530 and determine whether miR-4530 was able to regulate angiogenesis in breast carcinoma cells by targeting VASH1. MDA-MB-231 and MCF-7 cells were transfected with miR-4530 precursor, anti-miR-4530 and empty vector plasmids. The expression levels of miRNA and mRNA were detected using the reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The expression levels of protein were detected using western blotting. Dual-luciferase reporter assays were used to identify the target of miR-4530. Furthermore, cell proliferation, cell cycle, apoptosis and tube formation assays were used to investigate the function of miR-4530 in vitro. Nude mice were used in a subcutaneous tumor model in vivo study. The results of the present study demonstrated that miR-4530 significantly suppressed proliferation and promoted apoptosis of breast carcinoma cells. In addition, miR-4530 expression promoted angiogenesis in vitro. Results from the western blotting and RT-qPCR revealed that VASH1 was significantly downregulated by miR-4530 in breast carcinoma cells. The results of the present study suggest that miR-4530 promotes angiogenesis, inhibits proliferation and induces apoptosis in breast carcinoma cells by suppressing the expression of VASH1.

Innovative approach in assessing the role of neurogenesis, angiogenesis, and lymphangiogenesis in the pathogenesis of external genital endometriosis

Endometriosis is a chronic, progressive, relapsing estrogen-dependent disorder characterized by the growth of tissue structure and function similar to the endometrium outside the normal mucosa of the uterine cavity localization. Endometriosis is found in 10-15% of women in reproductive age and it is one of the main causes of pelvic pain syndrome and infertility. Mechanisms of the development of endometriosis and related pathological pain impulses are still poorly understood and therapeutic approaches do not always have a sufficient effect; in this connection, the study of the pathogenesis of endometriosis and endometriosis-associated pain currently is perspective. Identification of significant factors of angiogenesis, lymphangiogenesis, and neurogenesis in the external genital endometriosis will promote the development of non-invasive early diagnosis and pathogenetic therapy.

Vasohibin-1 suppresses colon cancer

Vasohibin-1 (VASH1) is an endogenous angiogenesis inhibitor.However, the clinical relevance of VASH1 in colon cancer and its regulations on cancer angiogenesis and cancer cell biological characteristics are still unknown. Here we showed that stromal VASH1 levels were negatively correlated with tumor size, advanced clinical stage and distant metastases in colon cancer patients. Overexpression of VASH1 in colon cancer cells induced apoptosis and senescence, inhibiting cancer cell growth and colony formation in vitro and tumor growth in vivo. In addition, knockdown of VASH1 in cancer cells promoted cell growth, adhesion and migration in vitro, and enhanced tumorigenesis and metastasis in vivo.

Proteolytic inactivation of anti-angiogenic vasohibin-1 by cancer cells

Vasohibin-1 (VASH1) is an angiogenesis inhibitor synthesized by endothelial cells (ECs) under conditions associated with physiological and pathological angiogenesis including cancers. VASH1, which is a 44-kDa protein, is processed after its translation and secretion, and a 29 kDa product cleaved both N-terminal and C-terminal end loses its anti-angiogenic activity. Here, we tested whether cancer cells modulate the processing of VASH1. When mouse EC line MS1 stably overexpressing the human VASH1 gene (MS1-hVASH1) and various cancer cell lines were co-cultured, there was an increased processing of hVASH1 protein in the culture media. This augmented processing was abrogated by a general cysteine protease inhibitor, E-64, and also by a specific calpain inhibitor, MDL28170. Recombinant hVASH1 protein was degraded by µ-calpain in vitro, which degradation was blocked by calpeptin. Conditioned media from co-cultures had little effect on the migration of human umbilical vein endothelial cells, but exhibited an inhibitory effect on their migration when collected in the presence of MDL28170; and this inhibitory effect was blocked by neutralizing anti-hVASH1 mAb. These results indicate that cancer cells proteolytically inactivate VASH1 protein secreted by ECs in the tumour microenvironment.

Distinctive role of vasohibin-1A and its splicing variant vasohibin-1B in tumor angiogenesis

Vasohibin-1 (VASH1) was isolated as a negative-feedback regulator of angiogenesis expressed in endothelial cells (ECs). There are two transcripts of VASH1, that is, the full-length VASH1A consisting of seven exons and the splicing variant VASH1B consisting of four exons. Here, we compared the effects of VASH1A and VASH1B on tumor angiogenesis. When ECs were transfected with VASH1A or VASH1B cDNAs, VASH1B transfectants, but not VASH1A ones, induced autophagic cell death of ECs. With sonoporation, the VASH1A or VASH1B gene were transfected specifically in ECs of tumor vessels in mice. Both VASH1A and VASH1B decreased tumor vessel density and inhibited tumor growth. VASH1A normalized the remaining tumor vessels, increased their rate of perfusion, decreased tumor hypoxia and enhanced the efficacy of anticancer chemotherapy, whereas VASH1B pruned tumor vessels without causing normalization, increased tumor hypoxia and tumor necrosis and did not enhance the efficacy of anticancer chemotherapy. The alternate transfection of mice with the VASH1A and VASH1B gene showed the highest effects on antitumor activity and normalization of tumor vessels. Our present findings on VASH1A and VASH1B should provide an innovative approach that would improve the efficacy of antiangiogenic cancer therapy by balancing vascular normalization and pruning.

Tumor lymphangiogenesis and new drug development

Traditionally, tumor-associated lymphatic vessels have been regarded as passive by-standers, serving simply as a drainage system for interstitial fluid generated within the tumor. However, with growing evidence that tumors actively induce lymphangiogenesis, and that the number of lymphatic vessels closely correlates with metastasis and clinical outcome in various types of cancer, this picture has changed dramatically in recent years. Tumor-associated lymphatic vessels have now emerged as a valid therapeutic target to control metastatic disease, and the first specific anti-lymphangiogenic drugs have recently entered clinical testing. Furthermore, we are just beginning to understand the whole functional spectrum of tumor-associated lymphatic vessels, which not only concerns transport of fluid and metastatic cells, but also includes the regulation of cancer stemness and specific inhibition of immune responses, opening new venues for therapeutic applications. Therefore, we predict that specific targeting of lymphatic vessels and their function will become an important tool for future cancer treatment.

Vasohibin-1 expression inhibits advancement of ovarian cancer producing various angiogenic factors

Vasohibin‐1 (VASH1) is a negative feedback regulator of angiogenesis, the first to be discovered, and was identified in vascular endothelial growth factor (VEGF)‐stimulated vascular endothelial cells. Vasohibin‐1 inhibits abnormal vascularization induced by various angiogenic factors including fibroblast growth factor and platelet‐derived growth factor (PDGF), in addition to VEGF. By focusing on this characteristic of VASH1, we investigated the antitumor effects of VASH1 expression on ovarian cancer cells that produce different angiogenic factors. By using a high VEGF‐producing ovarian cancer cell line, SHIN‐3, and a high PDGF‐producing ovarian cancer cell line, KOC‐2S, the cells were transfected with either a VEGF antagonist, soluble VEGF receptor‐1 (sVEGFR‐1, or sFlt‐1), or VASH1 genes to establish their respective cellular expression. The characteristics of these transfectants were compared with controls. We previously reported that the expression of sFlt‐1 inhibited tumor vascularization and growth of high VEGF‐producing ovarian cancer cells, reduced peritoneal dissemination and ascites development, and prolonged the survival time of the host. However, in the current study, the expression of sFlt‐1 had no such effect on the high PDGF‐producing ovarian cancer cells used here, whereas VASH1 expression inhibited tumor vascularization and growth, not only in high VEGF‐producing cells, but also in high PDGF‐producing cells, reduced their peritoneal dissemination and ascites, and prolonged the survival time of the host. These results suggest that VASH1 is an effective treatment for ovarian cancer cells that produce different angiogenic factors.

The Naïve Murine Cornea as a Model System to Identify Novel Endogenous Regulators of Lymphangiogenesis: TRAIL and rtPA

BACKGROUND

In the murine cornea, which is an established model for analyzing pathologic lymphatic vessel growth, phenotypic heterogeneity of the endogenous lymphatic vessels in the limbus of the cornea was previously described. In this study, the cornea of BALB/c, C57BL/6, and FVB mice with different limbal lymphangiogenic phenotypes was analyzed to identify novel candidates potentially influencing lymphatic vessel growth.

METHODS AND RESULTS

Pathway specific expression analysis of the cornea was performed to identify novel candidate genes. Corneal protein expression of the respective candidates was analyzed by fluorescent immunohistochemistry. The effect of the candidates on proliferation of human dermal lymphatic endothelial cells (HDLECs) was analyzed by BrdU proliferation ELISA. Thirteen genes were differentially regulated in corneas of mouse strains with more endogenous limbal lymphatic vessels (high-lymphangiogenic) (C57BL/6) compared to mouse strains with less endogenous limbal lymphatic vessels (low-lymphangiogenic) (BALB/c, FVB). Two candidates, Tumor necrosis factor (ligand) superfamily member 10 (Tnfsf10/Trail) and Plasminogen activator, tissue (Plat/tPA) were expressed in the cornea of BALB/c and C57BL/6 mice on the protein level. In vitro, Trail and recombinant tPA inhibited the proliferation of human dermal lymphatic endothelial cells.

CONCLUSION

Molecular analysis of the naive cornea in mouse strains with different limbal lymphatic phenotypes is a valuable model to identify novel endogenous regulators of lymphangiogenesis.

Understanding lymphangiogenesis in knockout models, the cornea, and ocular diseases for the development of therapeutic interventions

A major focus of cancer research for several decades has been understand the ability of tumors to induce new blood vessel formation, a process known as angiogenesis. Unfortunately, only limited success has been achieved in the clinical application of angiogenesis inhibitors. We now know that lymphangiogenesis, the growth of lymphatic vessels, likely also plays a major role in tumor progression. Thus, therapeutic strategies targeting lymphangiogenesis or both lymphangiogenesis and angiogenesis may represent promising approaches for treating cancer and other diseases. Importantly, research progress toward understanding lymphangiogenesis is significantly behind that related to angiogenesis. A PubMed search of "angiogenesis" returns nearly 80,000 articles, whereas a search of "lymphangiogenesis" returns 2,635 articles. This stark contrast can be explained by the lack of molecular markers for identifying the invisible lymphatic vasculature that persisted until less than 2 decades ago, combined with the intensity of research interest in angiogenesis during the past half century. Still, significant strides have been made in developing strategies to modulate lymphangiogenesis, largely using ocular disease models. Here we review the current knowledge of lymphangiogenesis in the context of knockout models, ocular diseases, the biology of activators and inhibitors, and the potential for therapeutic interventions targeting this process.

The angiogenesis regulator vasohibin-1 inhibits ovarian cancer growth and peritoneal dissemination and prolongs host survival

Vasohibin-1 (VASH1) is expressed in vascular endothelial cells stimulated by several angiogenic growth factors and displays autocrine activity to regulate angiogenesis via a negative feedback mechanism. In this study, we investigated the effect of VASH1 on ovarian cancer progression using VASH1-expressing ovarian cancer cells in vitro and in vivo. The growth ability of ovarian cancer cells engineered to express the VASH1 gene remained unchanged in vitro. However, we showed that VASH1 secretion by tumor cells inhibited the growth of human umbilical vein endothelial cells. Further, animal experiments showed that VASH1 expression inhibited tumor angiogenesis and growth. In a murine model of peritoneal dissemination of ovarian cancer cells, VASH1 inhibited peritoneal dissemination and ascites, resulting in significantly prolonged survival in mice. This indicates that VASH1 exerts an antitumor effect on ovarian cancer by inhibiting angiogenesis in the tumor environment. These findings suggest that a novel therapy based on VASH1 could be a useful therapeutic strategy for ovarian cancer.

Prevention of recurrent pterygium with topical bevacizumab 0.05% eye drops: a randomized controlled trial

PURPOSE

We assessed the efficacy and tolerability of topical bevacizumab 0.05% when used as an adjunctive therapy after excision of primary pterygia.

METHODS

This randomized double-masked study included 22 patients (22 eyes) with primary pterygia who underwent pterygium surgery with the use of the bare sclera technique. After pterygium excision, 22 patients were randomized to receive the topical bevacizumab 0.05% (12 eyes) or the placebo (10 eyes) with the use of the block of four randomization method. Topical bevacizumab and placebo were applied in the respective groups 4 times daily for 3 months. Follow-up evaluations for recurrence by slit-lamp photography were conducted once monthly. Ocular and systemic adverse events were assessed every 2 weeks during the 3 months of treatment. The slit-lamp photographs were masked and analyzed. The primary and secondary outcomes were the differences in the pterygial recurrence rates between the groups and adverse events at 3 months, respectively. Corneal recurrence was defined as recurrent fibrovascular tissue invading the cornea; conjunctival recurrence was defined as either recurrent vessels or fibrous tissue in the excised area without corneal invasion.

FINDINGS

All 22 patients completed follow-up at 3 months after the start of the trial medications. After 3 months of treatment, 1 patient (8.33%) and 3 patients (30.00%) from the bevacizumab and placebo groups, respectively, had a corneal recurrence. No significant (P = 0.293) differences were found between the groups as determined by Fisher's exact test. However, conjunctival and corneal recurrences were found in 4 (33.33%) and 9 (90.00%) patients, respectively, in the bevacizumab and placebo groups, a difference that reached significance (P = 0.01). No significant adverse events developed.

IMPLICATIONS

Topical bevacizumab, as an adjunctive treatment after pterygium excision, was well tolerated. The trend for recurrence was lower in the topical bevacizumab group. ClinicalTrials.gov identifier: NCT01311960.

Exacerbation of diabetic renal alterations in mice lacking vasohibin-1

Vasohibin-1 (VASH1) is a unique endogenous inhibitor of angiogenesis that is induced in endothelial cells by pro-angiogenic factors. We previously reported renoprotective effect of adenoviral delivery of VASH1 in diabetic nephropathy model, and herein investigated the potential protective role of endogenous VASH1 by using VASH1-deficient mice. Streptozotocin-induced type 1 diabetic VASH1 heterozygous knockout mice (VASH1^+/−) or wild-type diabetic mice were sacrificed 16 weeks after inducing diabetes. In the diabetic VASH1^+/− mice, albuminuria were significantly exacerbated compared with the diabetic wild-type littermates, in association with the dysregulated distribution of glomerular slit diaphragm related proteins, nephrin and ZO-1, glomerular basement membrane thickning and reduction of slit diaphragm density. Glomerular monocyte/macrophage infiltration and glomerular nuclear translocation of phosphorylated NF-κB p65 were significantly exacerbated in the diabetic VASH1^+/− mice compared with the diabetic wild-type littermates, accompanied by the augmentation of VEGF-A, M1 macrophage-derived MCP-1 and phosphorylation of IκBα, and the decrease of angiopoietin-1/2 ratio and M2 macrophage-derived Arginase-1. The glomerular CD31⁺ endothelial area was also increased in the diabetic VASH1^+/− mice compared with the diabetic-wild type littermates. Furthermore, the renal and glomerular hypertrophy, glomerular accumulation of mesangial matrix and type IV collagen and activation of renal TGF-β₁/Smad3 signaling, a key mediator of renal fibrosis, were exacerbated in the diabetic VASH1^+/− mice compared with the diabetic wild-type littermates. In conditionally immortalized mouse podocytes cultured under high glucose condition, transfection of VASH1 small interfering RNA (siRNA) resulted in the reduction of nephrin, angiopoietin-1 and ZO-1, and the augmentation of VEGF-A compared with control siRNA. These results suggest that endogenous VASH1 may regulate the development of diabetic renal alterations, partly via direct effects on podocytes, and thus, a strategy to recover VASH1 might potentially lead to the development of a novel therapeutic approach for diabetic nephropathy.

Disruption of negative feedback loop between vasohibin-1 and vascular endothelial growth factor decreases portal pressure, angiogenesis, and fibrosis in cirrhotic rats

Pathological angiogenesis represents a critical hallmark for chronic liver diseases. Understanding the mechanisms regulating angiogenesis is essential to develop new therapeutic strategies that specifically target pathological angiogenesis without affecting physiological angiogenesis. Here we investigated the contribution and therapeutic impact of the endogenous angioinhibitor vasohibin-1 in portal hypertension and cirrhosis. The spatiotemporal expression profiling of vasohibin-1 and its relationship with vascular endothelial growth factor (VEGF), angiogenesis, and fibrogenesis was determined through the analysis of human cirrhotic liver specimens, widely accepted in vivo animal models of portal hypertension and cirrhosis, and in vitro angiogenesis assays. Effects of vasohibin-1 overexpression by adenoviral-mediated gene transfer on angiogenesis, fibrogenesis, and portal hypertension-associated hemodynamic alterations were also studied in rats. We found that vasohibin-1 and VEGF are up-regulated, in mesentery and liver, in cirrhotic and precirrhotic portal hypertensive rats and cirrhosis patients. Our results are consistent with vasohibin-1/VEGF cascades being spatially and temporally coordinated through a negative-feedback loop driving pathological angiogenesis. Paradoxically, further overexpression of vasohibin-1 by adenoviral gene transfer exerts multifold beneficial effects in portal hypertension and cirrhosis: reduction of pathologic angiogenesis, attenuation of liver fibrogenesis partly mediated through inhibition of hepatic stellate cell activation, and significant decreases in portocollateralization, splanchnic blood flow, portohepatic resistance, and portal pressure. The explanation for this apparent contradiction is that, unlike endogenous vasohibin-1, the ectopic overexpression is not regulated by VEGF and therefore disrupts the negative-feedback loop, thus generating constant, but lower levels of VEGF synthesis sufficient to maintain vascular homeostasis but not pathological angiogenesis.

CONCLUSION

Our study provides evidence that vasohibin-1 regulates portal hypertension-associated pathological angiogenesis and highlights that increasing vasohibin-1 might be a promising novel therapeutic strategy for portal hypertension and cirrhosis.

RhoB controls coordination of adult angiogenesis and lymphangiogenesis following injury by regulating VEZF1-mediated transcription

Mechanisms governing the distinct temporal dynamics that characterize post-natal angiogenesis and lymphangiogenesis elicited by cutaneous wounds and inflammation remain unclear. RhoB, a stress-induced small GTPase, modulates cellular responses to growth factors, genotoxic stress and neoplastic transformation. Here we show, using RhoB null mice, that loss of RhoB decreases pathological angiogenesis in the ischaemic retina and reduces angiogenesis in response to cutaneous wounding, but enhances lymphangiogenesis following both dermal wounding and inflammatory challenge. We link these unique and opposing roles of RhoB in blood versus lymphatic vasculatures to the RhoB-mediated differential regulation of sprouting and proliferation in primary human blood versus lymphatic endothelial cells. We demonstrate that nuclear RhoB-GTP controls expression of distinct gene sets in each endothelial lineage by regulating VEZF1-mediated transcription. Finally, we identify a small-molecule inhibitor of VEZF1-DNA interaction that recapitulates RhoB loss in ischaemic retinopathy. Our findings establish the first intra-endothelial molecular pathway governing the phased response of angiogenesis and lymphangiogenesis following injury.

Urinary and plasma levels of vasohibin-1 can predict renal functional deterioration in patients with renal disorders

Vasohibin-1 (VASH-1) is a negative feedback regulator of angiogenesis, and a small vasohibin-binding protein (SVBP) serves as its secretory chaperone and contributes to its antiangiogenic effects. In the present study, we aimed to define the clinical significance of VASH-1 and SVBP in patients with chronic kidney disease (CKD). We recruited 67 Japanese hospitalized patients with renal disorders with (n = 45) or without (n = 22) renal biopsy samples and 10 Japanese healthy controls. We evaluated the correlations between the plasma and urinary levels of VASH-1/VASH-1-SVBP complex/SVBP and the clinicopathological parameters. The plasma levels of VASH-1 were inversely correlated with age and systolic and diastolic blood pressure and positively correlated with crescent formation. Increased plasma and urinary levels of VASH-1 and VASH-1-SVBP complex were significantly correlated with worse renal outcomes. These results demonstrate an association between elevated urinary and plasma levels of VASH-1 and progressive decline of the renal function, thus suggesting a potential role for VASH-1 in predicting a worse renal prognosis in patients with renal disease, including CKD.

Vasohibin-2 modulates tumor onset in the gastrointestinal tract by normalizing tumor angiogenesis

Background

Vasohibin-2 (VASH2) has been identified as an endogenous and vascular endothelial growth factor (VEGF)-independent angiogenic factor that is highly expressed in tumor cells. In the present study, we aimed to determine whether pre-existing vascular changes can be used to predict tumor transformation as benign or malignant. We sought to characterize microvascular changes and tumor development in the intestinal tract of Apc^Min/+ mice and Apc^Min/+/Vash2^-/- mice.

Methods

Apc^Min/+ mice provide a unique orthotopic model for the development of spontaneous adenomatous polyposis and subsequent carcinomas, a phenomenon termed the adenoma-carcinoma sequence. Apc^Min/+ mice were mated with Vash2^-/- mice with a mixed C57BL/6 background and the resulting pups were screened for the Min mutation and for the Vash2^-/- gene by PCR. Intestinal tumors from Apc^Min/+ mice and Apc^Min/+/Vash2^-/- mice were removed and either frozen or epon-embedded for subsequent analyses. For 3-dimensional imaging using confocal laser-scanning microscopy and transmission electron microscopy, cryosections were made, and immunofluorescent staining for various markers was performed.

Results

We found that structural abnormalities in tumor vessels from benign tumors resembled those in malignant tumors. In addition, a novel angiogenic factor, vasohibin-2 (VASH2) protein, was detected around tumor blood vessels in late-stage adenomas and adenocarcinomas, but was absent from early-stage adenomas in Apc^Min/+ mice. Tumors used to examine endogenous VASH2 (derived from CMT93 colon carcinomas) were less vascularized in Vash2^-/- mice and were more regular than those seen in wild-type (WT) mice. In addition, tumors in Vash2^-/- mice were smaller than those in WT mice. Furthermore, cross-breeding of mice homozygous for a deletion of Vash2 with mice heterozygous for the APC mutation resulted in animals that showed a significant decrease in the number of polyps in the small intestine.

Conclusion

We propose that VASH2 may modulate the onset of tumors in the gastrointestinal tract by regulating tumor angiogenesis.

In vivo delivery of siRNA targeting vasohibin-2 decreases tumor angiogenesis and suppresses tumor growth in ovarian cancer

Vasohibin-2 (VASH2) is a homolog of vasohibin-1 and exhibits pro-angiogenic activity. We recently reported that VASH2 is expressed in certain ovarian cancers and promotes tumor growth through angiogenesis. To further demonstrate the effectiveness of molecular targeting of VASH2 for anticancer treatment, we applied in vivo delivery of siRNA targeting VASH2 (siVASH2) using atelocollagen to a xenograft model of ovarian cancer. We inoculated mice s.c. with DISS and SKOV-3, two representative human ovarian serous adenocarcinoma cell lines. When tumors were measurable, we initiated treatment with control or siVASH2 mixed with atelocollagen, which enveloped the whole tumor. Treatment with siVASH2 significantly inhibited s.c. tumor growth by abrogating tumor angiogenesis. We confirmed that expression of VASH2 mRNA in the tumor was downregulated by siVASH2 treatment. In addition, the siVASH2-treated tumor contained more blood vessels covered with pericytes, indicating that knockdown of VASH2 contributes to the normalization of tumor blood vessels. Based on these results, VASH2 may be a promising molecular target for ovarian cancer treatment.