Endostar attenuates melanoma tumor growth via its interruption of b-FGF mediated angiogenesis

The anti-angiogenic and anti-vasculogenic mimicry effects of GN25 in endothelial and glioma cells

BACKGROUND AND PURPOSE

Scientists have been exploring anti-angiogenic strategies to inhibit angiogenesis and prevent tumor growth. Vasculogenic mimicry (VM) in glioblastoma multiforme (GBM) poses a challenge, complicating anti-angiogenesis therapy. A novel drug, GN25 (3-[{1,4-dihydro-5,8-dimethoxy-1,4-dioxo-2-naphthalenyl}thio]-propanoic acid), can inhibit tumor formation. This study aims to investigate the microenvironmental effects and molecular mechanisms of GN25 in anti-angiogenesis and anti-VM.

EXPERIMENTAL APPROACH

MTT (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) assay was used to evaluate the cell viability of different concentrations of GN25 in human umbilical vein endothelial cells (HUVEC) and Uppsala 87 malignant glioma (U87MG) cells. Functional assays were used to investigate the effects of GN25 on angiogenesis-related processes, whereas gelatin zymography, enzyme-linked immunosorbent assays, and Western blotting were utilized to assess the influence on matrix metalloproteinase (MMP)-2 and vascular endothelial growth factor (VEGF) secretion and related signaling pathways.

KEY RESULTS

GN25 suppressed migration, wound healing, and tube formation in HUVECs and disrupted angiogenesis in a rat aorta ring and zebrafish embryo model. GN25 dose-dependently reduced phosphatidylinositol 3-kinase/AKT and inhibited MMP-2/VEGF secretion in HUVECs. In U87MG cells, GN25 inhibited migration, wound healing, and VM, accompanied by a decrease in MMP-2 and VEGF secretion. The results indicate that GN25 effectively inhibits angiogenesis and VM formation in HUVECs and U87MG cells without affecting preexisting vascular structures.

CONCLUSION AND IMPLICATIONS

This study elaborated GN25's potential as an anti-angiogenic agent by elucidating its inhibitory effects on classical angiogenesis. VM provides valuable insights for developing novel therapeutic strategies against tumor progression and angiogenesis-related diseases. These results indicate the potential of GN25 as a promising candidate for angiogenesis-related diseases.

A Reconfigurable DNA Framework Nanotube-Assisted Antiangiogenic Therapy

A major limitation of tumor antiangiogenic therapy is the pronounced off-target effect, which can lead to unavoidable injury in multiple organs. Ensuring sufficient delivery and controlled release of these antiangiogenic agents at tumor sites is crucial for realizing their clinical application. Here, we develop a smart DNA-based nanodrug, termed Endo-rDFN, by precisely assembling the antiangiogenic agent, endostar (Endo), into a reconfigurable DNA framework nanotube (rDFN) that could recognize tumor-overexpressed nucleolin to achieve the targeted delivery and controllable release of Endo. Endo-rDFN can not only effectively enhance the tumor-targeting capability of Endo and maintain its efficient accumulation in tumor tissues but also achieve on-demand release of Endo at tumor sites via the specific DNA aptamer for tumor-overexpressed nucleolin, named AS1411. We also found that Endo-rDFN exhibited significant inhibition of angiogenesis and tumor growth, while also providing effective protection against multiorgan injury (heart, liver, spleen, kidney, lung, etc.) to some extent, without compromising the function of these organs. Our study demonstrates that rDFN represents a promising vector for reducing antiangiogenic therapy-induced multiorgan injury, highlighting its potential for promoting the clinical application of antiangiogenic agents.

Generation and utilization of endostatin-sensitive cell lines for assessing the biological activity of endostatin

Recombinant proteins are gaining increasing popularity for treating human diseases. The clinical effectiveness of recombinant proteins is directly related to their biological activity, which is an important indicator in drug development and quality control. However, certain recombinant proteins have unclear or complex signal pathways, making detecting their activity in vitro difficult. For instance, recombinant human endostatin (endostatin), a new antitumor drug developed in China, lacks a sensitive and stable assay for its biological activity since being market approval. To address this issue, we performed a genome-wide screening of immortalized human umbilical vein endothelial cells (HUVECs) using a CRISPR/Cas9 knockout library containing 20,000 targeted genes. We identified two potential endostatin-resistant genes, NEPSPP and UTS2, and successfully constructed a highly sensitive cell line, HUVEC-UTS2-3#, by knocking down the UTS2 gene. Based on the optimized parameters of HUVEC-UTS2-3# cells, we established a new method for detecting the biological activity of endostatin. The method was validated, and it produced results consistent with primary HUVEC cells but with higher sensitivity and more stable data. The use of gene-editing technology provides a novel solution for detecting the biological activity of recombinant proteins that other methods cannot detect.

Bidirectional crosstalk between therapeutic cancer vaccines and the tumor microenvironment: Beyond tumor antigens

Immunotherapy has rejuvenated cancer therapy, especially after anti-PD-(L)1 came onto the scene. Among the many therapeutic options, therapeutic cancer vaccines are one of the most essential players. Although great progress has been made in research on tumor antigen vaccines, few phase III trials have shown clinical benefits. One of the reasons lies in obstruction from the tumor microenvironment (TME). Meanwhile, the therapeutic cancer vaccine reshapes the TME in an ambivalent way, leading to immune stimulation or immune escape. In this review, we summarize recent progress on the interaction between therapeutic cancer vaccines and the TME. With respect to vaccine resistance, innate immunosuppressive TME components and acquired resistance caused by vaccination are both involved. Understanding the underlying mechanism of this crosstalk provides insight into the treatment of cancer by directly targeting the TME or synergizing with other therapeutics.

Whole exome and transcriptome analysis revealed the activation of ERK and Akt signaling pathway in canine histiocytic sarcoma

Histiocytic sarcoma (HS) is an incurable aggressive tumor, and no consensus has been made on the treatment due to its rare occurrence. Since dogs spontaneously develop the disease and several cell lines are available, they have been advocated as translational animal models. In the present study, therefore, we explored gene mutations and aberrant molecular pathways in canine HS by next generation sequencing to identify molecular targets for treatment. Whole exome sequencing and RNA-sequencing revealed gene mutations related to receptor tyrosine kinase pathways and activation of ERK1/2, PI3K-AKT, and STAT3 pathways. Analysis by quantitative PCR and immunohistochemistry revealed that fibroblast growth factor receptor 1 (FGFR1) is over-expressed. Moreover, activation of ERK and Akt signaling were confirmed in all HS cell lines, and FGFR1 inhibitors showed dose-dependent growth inhibitory effects in two of the twelve canine HS cell lines. The findings obtained in the present study indicated that ERK and Akt signaling were activated in canine HS and drugs targeting FGFR1 might be effective in part of the cases. The present study provides translational evidence that leads to establishment of novel therapeutic strategies targeting ERK and Akt signaling in HS patients.

The mechanism of rh-endostatin-induced cardiotoxicity and its protection by dihydromyricetin[in vivo/in vitro, C57BL/6 mice, AC16 and hiPSC-CMs]

Recombinant human endostatin (rh-endostatin) is an anti-angiogenic drug, which is used for the treatment of advanced non-small-cell lung cancer (NSCLC) and other cancers. However, its side effects, especially the cardiotoxicity with unclear mechanisms limit its wide application in clinical practice. In this study, human cardiomyocyte cell line AC16 and human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) treated with different doses of rh-endostatin were used to analyze its effect on cardiac cell toxicity. The results revealed that rh-endostatin dose-dependently enhanced cardiomyocyte apoptosis through Apaf-1 apoptotic factor and apoptosis-related proteins such as p53. rh-endostatin-induced changes of mitochondrial function and mitophagy were involved in rh-endostatin-mediated cardiac cell toxicity. Rh-endostatin-induced cardiotoxicity was further verified in vivo in mice. Interestingly, Rh-endostatin-induced cardiotoxicity was inhibited by dihydromyricetin (DHM) both in cultured cells in vitro and in mouse hearts in vivo. The study provides new inside into rh-endostatin-induced cardiotoxicity and identified a novel potential medication DHM to overcome the serious adverse effect.

Antiangiogenic potential of Lepista nuda extract suppressing MAPK/p38 signaling-mediated developmental angiogenesis in zebrafish and HUVECs

The medicinal properties of natural/edible plant products and their use are popular in traditional practice owing to their nutritional contents with little to no side effects. Lepista nuda (L. nuda), an edible mushroom (Clitocybe nuda, commonly known as blewit), has attracted researchers to evaluate its contents and the mechanism of its activities. In the current study, we focused on evaluating the antiangiogenic effects of L. nuda water extract on zebrafish development and in vitro human umbilical vein endothelial cell (HUVEC) tube formation. Bioactive components such as ergothioneine, eritadenine, and adenosine were identified and quantified by HPLC analysis. The L. nuda extract showed antiangiogenic properties and inhibited intersegmental vessel (ISV), caudal vein plexus (CVP), hyaloid vessel (HV), and subintestinal vessel (SIV) development in Tg (fli1: EGFP) zebrafish embryos. The expression of angiogenesis-related genes (vegfaa, kdrl, vegfba, flt1, kdr) was affected following L. nuda extract treatment. L. nuda extract attenuated in vitro HUVEC tube formation, migration, and invasion. Furthermore, inhibition of MAPK/p38 signaling and depletion of proangiogenic genes, including growth factors (fgf, ang2, and vegfa); primary and accessory receptors (tie2, vegfr2, and eng); MMPs (mmp1 and mmp2); and cytokines (il-1α, il-1β, il-6, and tnf-α) was observed in HUVECs following L. nuda treatment. An in vivo zebrafish xenograft assay showed that L. nuda extract inhibited HuCCT1 cell-induced SIV sprouting in HuCCT1-injected embryos. Collectively, the results suggest that L. nuda could be a potential inhibitor of angiogenesis limiting cancer progression.

Scintigraphic Imaging of Neovascularization With 99mTc-3PRGD2 for Evaluating Early Response to Endostar Involved Therapies on Pancreatic Cancer Xenografts In Vivo

Background

Molecular imaging targeting angiogenesis can specifically monitor the early therapeutic effect of antiangiogenesis therapy. We explore the predictive values of an integrin αvβ3-targeted tracer, ^99mTc-PEG₄-E[PEG₄-c(RGDfK)]₂ (^99mTc-3PRGD₂), for monitoring the efficacy of Endostar antiangiogenic therapy and chemotherapy in animal models.

Methods

The pancreatic cancer xenograft mice were randomly divided into four groups, with seven animals in each group and treated in different groups with 10 mg/kg/day of Endostar, 10 mg/kg/day of gemcitabine, 10 mg/kg/day of Endostar +10 mg/kg/day of gemcitabine at the same time, and the control group with 0.9% saline (0.1 ml/day). ^99mTc-3PRGD₂ scintigraphic imaging was carried out to monitor therapeutic effects. Microvessel density (MVD) was measured using immunohistochemical staining of the tumor tissues. The region of interest (ROI) of tumor (T) and contralateral corresponding site (NT) was delineated, and the ratio of radioactivity (T/NT) was calculated. Two-way repeated-measure analysis of variance (ANOVA) was used to assess differences between treatment groups.

Results

Tumor growth was significantly lower in treatment groups than that in the control group (p < 0.05), and the differences were noted on day 28 posttreatment. The differences of ^99mTc-3PRGD₂ uptakes were observed between the control group and Endostar group (p = 0.033) and the combined treatment group (p < 0.01) on day 7 posttreatment and on day 14 posttreatment between the control group and gemcitabine group (p < 0.01). The accumulation of ^99mTc-3PRGD₂ was significantly correlated with MVD (r = 0.998, p = 0.002).

Conclusion

With ^99mTc-3PRGD₂ scintigraphic imaging, the tumor response to antiangiogenic therapy, chemotherapy, and the combined treatment can be observed at an early stage of the treatments, much earlier than the tumor volume change. It provides new opportunities for developing individualized therapies and dose optimization.

MiR-335 promotes corneal neovascularization by Targeting EGFR

Background

Corneal neovascularization (CRNV) is a severe threat to the vision of people. MicroRNA-335 (miR-335) has the function of facilitating angiogenesis. However, whether miR-335 regulates the progression of CRNV remains unclear.

Methods

The miR-335 expressions in CRNV rats induced by corneal suture and HUVECs induced by b-FGF were detected by quantitative real-time PCR. For the miR-335 function, wound healing and tube formation assays were performed. For the miR-335 mechanism, a dual-luciferase reporter gene assay was conducted. Besides, for the epidermal growth factor receptor (EGFR) function, Cell Counting Kit-8 and wound healing assays were performed. Meanwhile, the rescue assay was used to assess the miR-335/EGFR function in the migration and angiogenesis of b-FGF-treated HUVECs.

Results

Functionally, the miR-335 knockdown weakened the migration and angiogenesis of b-FGF-treated HUVECs, while the miR-335 overexpression showed an opposite trend. Mechanistically, miR-335 interacted with EGFR and negatively regulated the expression of EGFR. The rescue assay illustrated that miR-335 regulated the migration and angiogenesis of b-FGF-treated HUVECs through EGFR.

Conclusions

In general, our data confirmed that miR-335 facilitated the process of CRNV by targeting EGFR.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02481-0.

A monoclonal antibody against basic fibroblast growth factor attenuates cisplatin resistance in lung cancer by suppressing the epithelial-mesenchymal transition

Objectives: To investigate the underlying mechanisms of how the basic fibroblast growth factor monoclonal antibody (bFGFmAb) attenuates cisplatin (DDP) resistance in lung cancer using A549 cells and cisplatin-resistant A549 cells (A549/DDP). Methods: Cancer cell proliferation, cell viability, and 50% inhibitory concentration (IC50) of cisplatin were assessed. Transwell assays were utilized to evaluate the invasion activity of tumor cells in response to treatment. Epithelial-to-mesenchymal transition markers and drug resistance proteins were analysed using Western blots. Results: We demonstrate that the bFGFmAb inhibits the proliferation and invasion of both A549 and A549/DDP cells. The bFGFmAb increases cisplatin sensitivity of both A549 and A549/DDP cells as evidenced by an increase in the IC50 of cisplatin in A549 and A549/DDP cells. Furthermore, bFGFmAb significantly increases the expression of E-cadherin, whilst decreasing the expression of N-cadherin and bFGF in both cell lines, thereby showing inhibition of epithelial-to-mesenchymal transition. In addition, we demonstrate that bFGFmAb significantly reduces the expression of the lung resistance protein. Conclusions: Our data suggests that the humanized bFGFmAb is a promising agent to attenuate cisplatin resistance in NSCLC. The underlying mechanism for this effect of bFGFmAb may be associated with the inhibition of epithelial-to-mesenchymal transition and reduced expression of lung resistance protein.

Marine Bromophenol Bis(2,3,6-Tribromo-4,5-Dihydroxybenzyl)ether Inhibits Angiogenesis in Human Umbilical Vein Endothelial Cells and Reduces Vasculogenic Mimicry in Human Lung Cancer A549 Cells

Angiogenesis, including the growth of new capillary blood vessels from existing ones and the malignant tumors cells formed vasculogenic mimicry, is quite important for the tumor metastasis. Anti-angiogenesis is one of the significant therapies in tumor treatment, while the clinical angiogenesis inhibitors usually exhibit endothelial cells dysfunction and drug resistance. Bis(2,3,6-tribromo-4,5-dihydroxybenzyl)ether (BTDE), a marine algae-derived bromophenol compound, has shown various biological activities, however, its anti-angiogenesis function remains unknown. The present study illustrated that BTDE had anti-angiogenesis effect in vitro through inhibiting human umbilical vein endothelial cells migration, invasion, tube formation, and the activity of matrix metalloproteinases 9 (MMP9), and in vivo BTDE also blocked intersegmental vessel formation in zebrafish embryos. Moreover, BTDE inhibited the migration, invasion, and vasculogenic mimicry formation of lung cancer cell A549. All these results indicated that BTDE could be used as a potential candidate in anti-angiogenesis for the treatment of cancer.

Endostatin in Renal and Cardiovascular Diseases

Endostatin, a protein derived from the cleavage of collagen XVIII by the action of proteases, is an endogenous inhibitor known for its ability to inhibit proliferation and migration of endothelial cells, angiogenesis, and tumor growth. Angiogenesis is defined as the formation of new blood vessels from pre-existing vasculature, which is crucial in many physiological processes, such as embryogenesis, tissue regeneration, and neoplasia.

SUMMARY

Increasing evidence shows that dysregulation of angiogenesis is crucial for the pathogenesis of renal and cardiovascular diseases. Endostatin plays a pivotal role in the regulation of angiogenesis. Recent studies have provided evidence that circulating endostatin increases significantly in patients with kidney and heart failure and may also contribute to disease progression.

KEY MESSAGE

In the current review, we summarize the latest findings on preclinical and clinical studies analyzing the impact of endostatin on renal and cardiovascular diseases.

Endostatin inhibits the proliferation and migration of B16 cells by inducing macrophage polarity to M1‑type

Malignant melanoma is a common skin tumor that easily metastasizes and has a poor prognosis. Endostatin is an endogenous vascular endothelial inhibitor that mainly suppresses tumor growth by inhibiting the proliferation of vascular endothelial cells and by reducing the formation of tumor microvessels, however the immunological function of endostatin remains unclear. Previously, we have found that an over‑expression endostatin (pEndostatin) plasmid induced RAW264.7 cells' polarity to M1‑type macrophage. To elucidate the effect of M1‑type macrophages induced by endostatin on melanoma B16 cells, the present study transfected RAW264.7 cells with pEndostatin plasmid and co‑cultured them with B16 cells. Compared with the control group, the expression of matrix metalloproteinase (MMP)‑2, MMP‑9 and proliferating cell nuclear antigen in B16 cells was inhibited by M1‑type macrophages, but cleaved Caspase‑3 and cleaved Caspase‑8 were significantly upregulated and the ratio of Bax/Bcl‑2 was increased. These results indicated that M1 macrophages induced by pEndostatin plasmid inhibited the proliferation and migration of B16 cells and promoted their apoptosis. These findings suggest that the inhibitory effect of endostatin on melanoma is not limited to directly inhibiting tumor microvessel formation, but it may also be related to regulating changes in macrophage polarity.

Endostatin in fibrosis and as a potential candidate of anti-fibrotic therapy

Fibrotic diseases pose significant clinical challenges due to their broadness and complexity. Thus, a better understanding of fibrogenesis and the development of more effective treatments is imperative. Recent evidence suggests a significant antifibrotic potential of an endogenous glycoprotein, endostatin. While endostatin has been widely studied for its role as an anticancer adjuvant by inhibiting tumor angiogenesis, its possible implication in fibrosis remains largely unclear. Here, we review the role of endostatin in various cellular processes and highlight its antifibrotic activity. We hypothesize that endostatin conveys a homeostatic function in the process of fibrosis by regulating (a) TGF-β1 and its downstream signaling; (b) RhoA/ROCK pathway; (c) NF-κB signaling pathway; (d) expression of EGR-1; (e) PDGF/PDGFR pathway; (f) autophagy-related pathways; (g) pathways associated with cell proliferation and apoptosis. Finally, we propose a schematic model of the antifibrotic roles and mechanisms of endostatin; also, we outline future research directions of endostatin and aim to present a potential therapeutic approach for fibrosis.

Anti-tumor effect of local injectable hydrogel-loaded endostatin alone and in combination with radiotherapy for lung cancer

Endostatin (ES) can effectively inhibit neovascularization in most solid tumors and has the potential to make oxygen delivery more efficient and increase the efficacy of radiotherapy (RT). With a short half-life, ES is mainly administered systemically, which leads to low intake in tumor tissue and often toxic systemic side effects. In this study, we used hyaluronic acid-tyramine as a carrier to synthesize an ES-loaded hydrogel drug (ES/HA-Tyr) that can be injected locally. ES/HA-Tyr has a longer half-life and fewer systemic toxic side effects, and it exerts a better anti-angiogenic effect and anti-tumor effect with RT. In vitro, ES/HA-Tyr showed sustained release in the release assay and a stronger ability to inhibit the proliferation of human umbilical vascular endothelial cells (HUVECs) in the MTT assay; it exhibited a more potent effect against HUVEC invasion and a stronger anti-angiogenic effect on HUVECs in tube formation. In vivo, ES/HA-Tyr increased local drug concentration, decreased blood drug concentration, and caused less systemic toxicity. Further, ES/HA-Tyr effectively reduced tumor microvessel density, increased tumor pericyte coverage, decreased tumor hypoxia, and increased RT response. ES/HA-Tyr + RT also had increased anti-tumor and anti-angiogenic effects in Lewis lung cancer (LLC) xenograft models. In conclusion, ES/HA-Tyr showed sustained release, lower systemic toxicity, and better anti-tumor effects than ES. In addition, ES/HA-Tyr + RT enhanced anti-angiogenic effects, reduced tumor hypoxia, and increased the efficacy of RT in LLC-bearing mice.

Nomogram Incorporating the WNT/β-Catenin Signaling Pathway for Predicting the Survival of Cutaneous Melanoma

Background

Accurate prediction of the survival of cutaneous melanoma (CM) permits the selection of the optimal treatment. Currently, the TNM stage has limitations in predicting the survival of CM. There is evidence that the WNT/β-catenin signaling pathway has the potential to predict the CM prognosis. However, it still needs further investigation.

Objective

This study aims to establish a nomogram incorporating the WNT/β-catenin signaling pathway to improve the predicted accuracy of the overall survival (OS) of CM.

Methods

Two hundred and eighty CM patients were recruited and followed up. The clinicopathological characteristics and the key genes of the WNT/β-catenin signaling pathway (VEGF, β-catenin, and DKK1) were chosen as potential variables associated with the OS. In the training cohort (n = 190), a nomogram was built to estimate the 1-, 3-, and 5-year OS, and its discriminations and calibrations were valid by the verification cohort (n = 90). The predicted accuracies of the nomogram with or without the Wnt/β-catenin pathway and TNM stage were compared.

Results

A nomogram integrating independent risk factors (ulceration, lymph node metastasis, distant metastasis, Breslow thickness, dermal mitoses, β-catenin, VEGF, and DKK1), which were evaluated by a multivariate analysis, was constructed to predict the 1-, 3-, and 5-year OS of CM patients. Good discrimination and calibration were obtained regardless of the training or validation datasets. The nomogram incorporating the Wnt/β-catenin signaling pathway showed the highest accuracy [area under the curve (AUC)=0.914, 0.852, 0.785] compared with the nomogram without the Wnt/β-catenin signaling pathway (AUC=0.693, 0.640, 0.615) and the TNM stage (AUC=0.726, 0.693, 0.673).

Conclusion

The prognostic value of the established nomogram incorporating the WNT/β-catenin signaling pathway was better than it without WNT/β-catenin signaling pathway and TNM stage, which might be beneficial in the development of optimal treatment options.

Insights into Differentiation of Melanocytes from Human Stem Cells and Their Relevance for Melanoma Treatment

Simple Summary

The reactivation of embryonic developmental programs is crucial for melanoma cells to grow and to metastasize. In order to understand this process better, we first summarize the melanocytic differentiation process both in vivo and in vitro. Secondly, we compare and highlight important similarities between neural crest cell fate during differentiation and tumor cell characteristics during melanoma mestastasis. Finally, we suggest possible therapeutic targets, which could be used to inhibit phenotype switching by developmental cues and hence also suppress the metastatic melanoma spread.

Abstract

Malignant melanoma represents a highly aggressive form of skin cancer. The metastatic process itself is mostly governed by the so-called epithelial mesenchymal transition (EMT), which confers cancer cells migrative, invasive and resistance abilities. Since EMT represents a conserved developmental process, it is worthwhile further examining the nature of early developmental steps fundamental for melanocyte differentiation. This can be done either in vivo by analyzing the physiologic embryo development in different species or by in vitro studies of melanocytic differentiation originating from embryonic human stem cells. Most importantly, external cues drive progenitor cell differentiation, which can be divided in stages favoring neural crest specification or melanocytic differentiation and proliferation. In this review, we describe ectopic factors which drive human pluripotent stem cell differentiation to melanocytes in 2D, as well as in organoid models. Furthermore, we compare developmental mechanisms with processes described to occur during melanoma development. Finally, we suggest differentiation factors as potential co-treatment options for metastatic melanoma patients.

Overcoming Hypoxia-Restrained Radiotherapy Using an Erythrocyte-Inspired and Glucose-Activatable Platform

Radiotherapy (RT) as one of the most powerful cancer treatment strategies has been greatly restricted by tumor hypoxia. A mounting effort has been devoted to develop oxygen delivery systems for boosting the RT effect. Unluckily, those systems only supplied modest oxygen, which could not afford more than once and long-time RT. Herein, we describe the development of a glucose-regulated drug release platform, allowing for a long-term tumor normoxic microenvironment and repeated RT for a long time. The repeated cycles resulted in sustained high Endostar plasma levels, which dramatically normalized the tumor vasculature and chronically reversed tumor hypoxia. Taking advantage of the inexhaustible supply of oxygen, Endo@GOx-ER enabled RT achieved an impressive cancer treatment output. To the best of our knowledge, our strategy is the initial attempt to overcome tumor-hypoxia-limited RT through the normalization of tumor vasculature by using an erythrocyte-inspired and glucose-activatable platform and it visually casts a light on the clinical development.

Evaluation of collagen derived antiangiogenic factors and matrix metalloproteinases in anterior lens epithelial cells of pediatric eyes with persistent fetal vasculature

Purpose:

To measure levels of collagen-derived antiangiogenic factors (arresten, canstatin, tumstatin, endostatin) and matrix metalloproteinases (MMP-2 and MMP-9) in anterior lens epithelial cells (LECs) and anterior capsules of children with cataract and persistent fetal vasculature (PFV) as cases and cataract without PFV as controls.

Methods:

Anterior capsules harboring LECs were collected from pediatric cataract patients with (n = 13) and without PFV (n = 13) during surgery. Samples were immediately subjected to RNA extraction and cDNA preparation. Quantitative real time PCR was performed to determine the mRNA levels of antiangiogenic factors and matrix metalloproteinases. GAPDH (Glyceraldehyde 3-Phosphate Dehydrogenase) and β Actin were used as the housekeeping control. The mRNA levels were expressed as a ratio, using the delta-delta method for comparing the relative expression results between controls and cases. The non-parametric Mann-Whitney U test was applied for statistical evaluation. P values < 0.05 were statistically significant.

Results:

The relative mRNA levels of arresten, canstatin, tumstatin, endostatin, MMP-2 and MMP-9 in cases were 6.20E-03 ± 0.003, 1.49E-01 ± 0.02, 1.70E-01 ± 0.007, 3.20E-03 ± 0.003, 1.11E-03 ± 0.0009 and 3.72E-04 ± 0.0001. The mRNA levels of arresten was 1.6 times lower (P = 0.01) while mRNA levels of MMP-2, tumstatin and canstatin were 4, 2.5, and 2.3 times higher in cases than in controls. No change was observed in mRNA levels of MMP-9 and endostatin (P = 0.82).

Conclusion:

A significant difference in the levels of arresten, canstatin, tumstatin, and MMP-2 was found in LECs with PFV.

Collagen Peptides Isolated from Salmo salar and Tilapia nilotica Skin Accelerate Wound Healing by Altering Cutaneous Microbiome Colonization via Upregulated NOD2 and BD14

Collagen peptides can promote wound healing and are closely related to microbiome colonization. We investigated the relationship among collagen peptides, wound healing, and wound microflora colonization by administering the murine wound model with Salmo salar skin collagen peptides (Ss-SCPs) and Tilapia nilotica skin collagen peptides (Tn-SCPs). We analyzed the vascular endothelial growth factor (VEGF), fibroblast growth factors (β-FGF), pattern recognition receptor (NOD2), antimicrobial peptides (β-defence14, BD14), proinflammatory (TNF-α, IL-6, and IL-8) and anti-inflammatory (IL-10) cytokines, macrophages, neutrophil infiltration levels, and microbial communities in the rat wound. The healing rates of the Ss-SCP- and Tn-SCP-treated groups were significantly accelerated, associated with decreased TNF-α, IL-6, and IL-8 and upregulated BD14, NOD2, IL-10, VEGF, and β-FGF. Accelerated healing in the collagen peptide group shows that the wound microflora such as Leuconostoc, Enterococcus, and Bacillus have a positive effect on wound healing (P < 0.01). Other microbiome species such as Stenotrophomonas, Bradyrhizobium, Sphingomonas, and Phyllobacterium had a negative influence and decreased colonization (P < 0.01). Altogether, these studies show that collagen peptide could upregulate wound NOD2 and BD14, which were implicated in microflora colonization regulation in the wound tissue and promoted wound healing by controlling the inflammatory reaction and increasing wound angiogenesis and collagen deposition.

The association between maternal nicotine exposure and adipose angiogenesis in female rat offspring: A mechanism of adipose tissue function changes

Maternal smoking during pregnancy and lactation is associated with increased fat mass in the offspring, but the mechanism by which this occurs is not fully understood. Our study focused on the relationships among maternal nicotine exposure, adipose angiogenesis and adipose tissue function in female offspring. Pregnant rats were randomly assigned to nicotine or control groups. Microvascular density, lipid metabolism and α7nAChR-Egr1-FGF2 signaling pathway genes/proteins were tested in 4-, 12- and 26-week female offspring. In vitro, nicotine concentration- and time-response experiments were conducted in 3T3-L1. Lipid metabolism and α7nAChR-Egr1-FGF2 signaling pathway genes/proteins were tested. The conditioned media of differentiated 3T3-L1 treated with nicotine were used to observe tube formation in human umbilical vein endothelial cells (HUVECs). Nicotine-exposed females presented higher adipose microvascular density. The gene expression of α7nAChR, Egr1 and FGF2 was significantly increased in gonadal white adipose tissue (gWAT) and inguinal subcutaneous WAT (igSWAT) of nicotine-exposed females at 4 weeks of age. The protein expression of α7nAChR, Egr1 and FGF2 was increased in gWAT and igSWAT of nicotine-exposed females at 4 weeks of age, and increased in gWAT at 26 weeks. In vitro, nicotine increased the expression of lipid metabolism and α7nAChR-Egr1-FGF2 signaling pathway genes/proteins in a concentration- and time-dependent manner. In the tube formation experiment, adipocytes affected by nicotine promoted HUVEC angiogenesis. Therefore, maternal nicotine exposure promoted the early angiogenesis of adipose tissue via the α7nAChR-Egr1-FGF2 signaling pathway, and this angiogenesis mechanism was associated with increased adipogenesis in adipose tissue of female offspring.

Focus on Formononetin: Anticancer Potential and Molecular Targets

Formononetin, an isoflavone, is extracted from various medicinal plants and herbs, including the red clover (Trifolium pratense) and Chinese medicinal plant Astragalus membranaceus. Formononetin's antioxidant and neuroprotective effects underscore its therapeutic use against Alzheimer's disease. Formononetin has been under intense investigation for the past decade as strong evidence on promoting apoptosis and against proliferation suggests for its use as an anticancer agent against diverse cancers. These anticancer properties are observed in multiple cancer cell models, including breast, colorectal, and prostate cancer. Formononetin also attenuates metastasis and tumor growth in various in vivo studies. The beneficial effects exuded by formononetin can be attributed to its antiproliferative and cell cycle arrest inducing properties. Formononetin regulates various transcription factors and growth-factor-mediated oncogenic pathways, consequently alleviating the possible causes of chronic inflammation that are linked to cancer survival of neoplastic cells and their resistance against chemotherapy. As such, this review summarizes and critically analyzes current evidence on the potential of formononetin for therapy of various malignancies with special emphasis on molecular targets.

FGF2 promotes metastasis of uveal melanoma cells via store-operated calcium entry

Uveal melanoma (UM), the most common primary intraocular malignancy in adults, is highly metastatic and associated with dismal prognosis. Fibroblast growth factor 2 (FGF2) has been shown to induce cell proliferation and angiogenesis of melanoma and other malignancies. However, the expression of FGF2 in UM and its effects on melanoma cell migration are not well known. In this study, we found FGF2 expression was related to UM histological subtype and presence of metastasis. In vitro experiments showed that FGF2 treatment caused increased horizontal and vertical migration and F-actin cytoskeleton assembly as well as decreased adhesive activity of MUM2B cells, together with increased intracellular calcium concentration and expression of ORAI1 and STIM1 – two key regulatory proteins of store-operated calcium entry (SOCE). The mouse xenograft model showed that MUM2B cells with FGF2 stimulation grew into larger tumor masses and were prone to metastasis. In addition, the SOCE inhibitor 2-aminoethoxydiphenyl borate (2-APB) reversed all of these effects of FGF2. Finally, human UM samples and mouse xenograft model samples were used to confirm the correlation of FGF2 with ORAI1 and STIM1 expression. Taken together, our study suggests that FGF2 promotes metastasis of UM via SOCE.

Differential effects of recombinant human endostatin treatment on differentiated and undifferentiated blood vessels in Lewis lung cancer

In the present study, we evaluated the effects of recombinant human (rh-)endostatin treatment on differentiated and undifferentiated tumor vasculature in Lewis lung cancer for the first time. Lewis lung carcinoma models were established. The animals were treated daily with varying doses of rh-endostatin or physiological saline for 14 days. Intravital microscopy was performed following treatment. The expression of CD31 and CD34 was determined by immunohistochemical staining, and microvessel density (MVD) was determined. Rh-endostatin treatment significantly decreased the tumor volume compared with the control group. Rh-endostatin treatment normalized the architecture of the vascular network. CD31⁺ cells decreased following rh-endostatin treatment, whereas CD34⁺ cells were unaffected by the treatment. Accordingly, the MVD value of CD31⁺ cells in rh-endostatin treatment groups significantly decreased (P<0.01), and the MVD value of CD34⁺ cells in the rh-endostatin treatment groups did not decrease. Undifferentiated tumor blood vessels were significantly inhibited by rh-endostatin treatment. In conclusion, the normalization of the tumor vasculature by endostatin may be related to the differential effects of endostatin on differentiated and undifferentiated blood vessels.

Thoracic perfusion of recombinant human endostatin (Endostar) combined with chemotherapeutic agents versus chemotherapeutic agents alone for treating malignant pleural effusions: a systematic evaluation and meta-analysis

Background

Endostar is a new endogenous angiogenic inhibitor with implicated anti-tumor activity. This study was to investigate whether thoracic perfusion of Endostar could be used to control malignant pleural effusions (MPE).

Methods

We searched the databases of MEDLINE, Web of Science, EMBASE, Goggle, Cochrance Library and CNKI to select the studies regarding the efficacy of Endostar to treat MPE. A total of 13 randomised controlled trials (RCTs) with 1066 patients were included.

Results

The overall response rate (ORR) (P < 0.001; odds ratio = 3.58) and disease control rate (DCR) (P < 0.001; odds ratio = 2.97) of Endostar combined with chemotherapeutic agents were significantly higher than those of chemotherapeutic agents alone. In addition, Endostar combined treatment remarkably promoted quality of life (QOL) of patients (P < 0.001; odds ratio = 3.04) compared with that of chemotherapeutic agents alone. Moreover, Endostar combined treatment did not have an impact on the incidence of adverse reactions (AEs) (P < 0.05).

Conclusions

The efficacy of Endostar combined chemotherapeutic agents was superior to chemotherapeutic agents alone through thoracic perfusion in treating MPE, which indicated that Endostar could be an effective agent for controlling MPE.

Formononetin, a novel FGFR2 inhibitor, potently inhibits angiogenesis and tumor growth in preclinical models

Most anti-angiogenic therapies currently being evaluated in clinical trials target vascular endothelial growth factor (VEGF) pathway, however, the tumor vasculature can acquire resistance to VEGF-targeted therapy by shifting to other angiogenesis mechanisms. Therefore, other potential therapeutic agents that block non-VEGF angiogenic pathways need to be evaluated. Here we identified formononetin as a novel agent with potential anti-angiogenic and anti-cancer activities. Formononetin demonstrated inhibition of endothelial cell proliferation, migration, and tube formation in response to basic fibroblast growth factor 2 (FGF2). In ex vivo and in vivo angiogenesis assays, formononetin suppressed FGF2-induced microvessel sprouting of rat aortic rings and angiogenesis. To understand the underlying molecular basis, we examined the effects of formononetin on different molecular components in treated endothelial cell, and found that formononetin suppressed FGF2-triggered activation of FGFR2 and protein kinase B (Akt) signaling. Moreover, formononetin directly inhibited proliferation and blocked the oncogenic signaling pathways in breast cancer cell. In vivo, using xenograft models of breast cancer, formononetin showed growth-inhibitory activity associated with inhibition of tumor angiogenesis. Moreover, formononetin enhanced the effect of VEGFR2 inhibitor sunitinib on tumor growth inhibition. Taken together, our results indicate that formononetin targets the FGFR2-mediated Akt signaling pathway, leading to the suppression of tumor growth and angiogenesis.

Gold Nanoparticle-Mediated Targeted Delivery of Recombinant Human Endostatin Normalizes Tumour Vasculature and Improves Cancer Therapy

Tumour vasculature is generally disordered because of the production of excessive angiogenic factors by tumour cells, which results in tumour progression and reduces the effectiveness of radiotherapy or chemotherapy. Transient anti-angiogenic therapies that regulate tumour vascular morphology and function and improve the efficiency of antitumour therapy are under investigation. Recombinant human endostatin (Endostar/rhES) is a vascular angiogenesis–disrupting agent that has been used to treat non-small cell lung cancer (NSCLC) in the clinical setting. In this study, we used gold nanoparticles (AuNPs) as a drug-delivery system (DDS) for targeted tumour delivery of rhES for short therapy, which resulted in transient tumour vascular normalization, reduced permeability and hypoxia, strengthened blood vessel integrity, and increased blood-flow perfusion. Moreover, combination therapy with 5-FU over this timeframe was substantially more effective than 5-FU monotherapy. In conclusion, our research demonstrates the potential use of AuNPs as a drug-delivery platform for transporting rhES into a tumour to induce transient tumour vascular normalization and enhance the antitumour efficacy of cytotoxic drugs.

Transcriptome profiling reveals differential expression of interferon family induced by dengue virus 2 in human endothelial cells on tissue culture plastic and polyacrylamide hydrogel

A cell model is critical for studying the molecular mechanisms of dengue virus 2 (DENV-2) invasions and cell bioactivity can be easily affected by the substrate matrix. Tissue culture plastic (TCP) and polyacrylamide hydrogel (PAMH) are two kinds of matrices widely used for cells. The effects of different matrices on the cultured cells with DENV-2 invasion remain unknown. To address the issue, the effects of TCP and PAMH were explored in primary human umbilical vein endothelial cells (HUVECs) with DENV-2 invasion. HUVECs were assigned into four groups: group A (cultured on TCP), group B (cultured on PAMH), group C (cultured on TCP with DENV-2 invasion), and group D (cultured on PAMH with DENV-2 invasion). Flow cytometry was performed on HUVECs after 48-hr culture. Gene expression patterns were analyzed by gene microarray. The levels of interleukin-29 (IL-29) were measured by real-time qRT-PCR and ELISA. There were no cell apoptosis induced by DENV-2 in HUVECs cultured on TCP and PAMH (P > 0.05). After DENV-2 invasion, the up-regulated genes involve in the activities of oligoadenylate synthetase (OAS), interferon-related cytokine, and growth factors so on. The up-regulated pathways involve in the responses to DENV-2 and innate immunity. IL-29 was induced in the HUVECs on PAMH when compared with the cells on TCP (P < 0.05). Thus, different matrices cause different immune responses, which should be considered in the cell models for exploring the molecular mechanisms of DENV-induced diseases.

FGFR inhibitors: Effects on cancer cells, tumor microenvironment and whole-body homeostasis (Review)

Fibroblast growth factor (FGF)2, FGF4, FGF7 and FGF20 are representative paracrine FGFs binding to heparan-sulfate proteoglycan and fibroblast growth factor receptors (FGFRs), whereas FGF19, FGF21 and FGF23 are endocrine FGFs binding to Klotho and FGFRs. FGFR1 is relatively frequently amplified and overexpressed in breast and lung cancer, and FGFR2 in gastric cancer. BCR-FGFR1, CNTRL-FGFR1, CUX1-FGFR1, FGFR1OP-FGFR1, MYO18A-FGFR1 and ZMYM2-FGFR1 fusions in myeloproliferative neoplasms are non-receptor-type FGFR kinases, whereas FGFR1-TACC1, FGFR2-AFF3, FGFR2-BICC1, FGFR2-PPHLN1, FGFR3-BAIAP2L1 and FGFR3-TACC3 fusions in solid tumors are transmembrane-type FGFRs with C-terminal alterations. AZD4547, BGJ398 (infigratinib), Debio-1347 and dovitinib are FGFR1/2/3 inhibitors; BLU9931 is a selective FGFR4 inhibitor; FIIN-2, JNJ-42756493, LY2874455 and ponatinib are pan-FGFR inhibitors. AZD4547, dovitinib and ponatinib are multi-kinase inhibitors targeting FGFRs, colony stimulating factor 1 receptor (CSF1R), vascular endothelial growth factor (VEGF)R2, and others. The tumor microenvironment consists of cancer cells and stromal/immune cells, such as cancer-associated fibroblasts (CAFs), endothelial cells, M2-type tumor-associating macrophages (M2-TAMs), myeloid-derived suppressor cells (MDSCs) and regulatory T cells. FGFR inhibitors elicit antitumor effects directly on cancer cells, as well as indirectly through the blockade of paracrine signaling. The dual inhibition of FGF and CSF1 or VEGF signaling is expected to enhance the antitumor effects through the targeting of immune evasion and angiogenesis in the tumor microenvironment. Combination therapy using tyrosine kinase inhibitors (FGFR or CSF1R inhibitors) and immune checkpoint blockers (anti-PD-1 or anti-CTLA-4 monoclonal antibodies) may be a promising choice for cancer patients. The inhibition of FGF19-FGFR4 signaling is associated with a risk of liver toxicity, whereas the activation of FGF23-FGFR4 signaling is associated with a risk of heart toxicity. Endocrine FGF signaling affects the pathophysiology of cancer patients who are prescribed FGFR inhibitors. Whole-genome sequencing is necessary for the detection of promoter/enhancer alterations of FGFR genes and rare alterations of other genes causing FGFR overexpression. To sustain the health care system in an aging society, a benefit-cost analysis should be performed with a focus on disease-free survival and the total medical cost before implementing genome-based precision medicine for cancer patients.

Effect of lentivirus-mediated integrin αVβ3-shRNA on tumor growth of mice with lung cancer xenografts

OBJECTIVE

To study the effect of lentivirus-mediated integrin αVβ3-shRNA on tumor growth of mice with lung cancer xenograft.

METHODS

Lung cancer tissue, paracancer tissue and normal tissue were collected and integrin αVβ3 expression was detected; BALB/c nude mice were selected, divided into integrin αVβ3 knockdown group (KD group) and negative control group (NC group), and inoculated with cells stably infected by integrin αVβ3-shRNA lentivirus and cells stably infected by negative control-shRNA lentivirus, respectively, the growth of tumor tissue was continuously observed, and the number of apoptosis cells as well as the expression of angiogenesis, apoptosis and invasion genes in tumor tissue were detected.

RESULTS

mRNA content and protein content of integrin αVβ3 in lung cancer tissue were significantly higher than those in paracancer tissue and normal tissue; increasing trend of tumor tissue volume of KD group was weaker than that of NC group, and tumor volume at various points in time of KD group was lower than that of NC group; mRNA contents and protein contents of VEGF, FGF, EGF, Bcl-2, MMP-9, MMP-12 and MMP-13 in tumor tissue of KD group were lower than those of NC group, and apoptosis index as well as mRNA content and protein content of Bax were higher than those of NC group.

CONCLUSIONS

The expression of integrin αVβ3 increases in lung cancer tissue, and lentivirus-mediated integrin αVβ3-shRNA can inhibit tumor growth of mice with lung cancer xenografts.

Hypoxia and TGF-β1 lead to endostatin resistance by cooperatively increasing cancer stem cells in A549 transplantation tumors

BACKGROUND

Lung cancer is the leading cause of cancer-related deaths worldwide, and treatments for lung cancer have a high failure rate. Anti-angiogenic therapy is also often ineffective because of refractory disease. Endostatin (ES) is one of the most widely-used anti-angiogenic drugs for lung cancer in China, and resistance to it is a barrier that needs to be resolved. It has been shown that myeloid-derived suppressor cells (MDSCs) are involved in resistance to ES. Whether other cells and/or cell factors in the tumor microenvironment that have been shown to be related to resistance to other anti-cancer drugs are also involved in ES resistance is unknown.

RESULTS

In this study, we showed that after continuously treatment with ES for 12 days, volumes of A549 transplantation tumors of mice reached the sizes of tumors which were borne by mice that were treated with normal saline and this meant that resistance to ES appeared. Cancer stem cells (CSCs), which have been widely accepted as one of reasons responsible for resistance to many anti-tumor drugs were also being discovered increased proportionally in A549 transplantation tumors after ES treatment for 12 days. During further exploration of reasons for this increase, we discovered that after ES treatment, microvessel density and vascular endothelial growth factor level was decreased in tumors, whereas transforming growth factor (TGF)-β1 level was elevated, and MDSCs, one of the sources of TGF-β1, were also increased. We speculate that hypoxia and TGF-β1 are responsible for the increased CSC number in A549 transplantation tumors. By using cobalt chloride to mimic hypoxia and human recombinant TGF-β1 in vitro, we found that hypoxia and TGF-β1can indeed enhance the stemness of A549 cells. In addition, the inductive effect of hypoxia is stronger than TGF-β1, and the combination of both is stronger than either alone, which is first report of such a finding, to our knowledge.

CONCLUSIONS

Increased TGF-β1 and strengthened hypoxia in A549 transplantation tumors, as a result of ES therapy, cooperatively increase proportion of CSCs that are involved in ES resistance which was revealed by failure of tumor volume repression after continuously treatment with ES for 12 days.

Effect of recombinant human endostatin onradiotherapy for esophagus cancer

OBJECTIVE

To investigate the effect of radiotherapy plus recombinant human endostatin (RH-endostatin) on esophageal cancer and its mechanism.

METHODS

A total of 50 nudemice were equally randomized into control group, radiotherapy group, and combined therapy group I, II, and III after inoculating with Eca109 cell suspension (1 × 10(7) cells/mL). On the day of grouping, control group and radiotherapy group were injected normal saline, while radiotherapy group and 3 combined therapy groups received radiotherapy; besides, combined therapy group I, II, and III was injected RH-endostatin of 2.5, 5, 10 mg/kg respectively. After 3-week therapy, the tumors of each group were collected and microvessel density and VEGF expression in tumors were determined. In vitro, Eca109 cells were divided into control group, radiotherapy group, and combined therapy group. Forty-eight hours after treatment, cell cycle distribution and apoptosis rate were detected, and the activity of VEGF signal paths was semiquantitatively analyzed.

RESULTS

Since the 6th day of treatment, the relative tumor proliferation rate of combined therapy group II was lower than radiotherapy group (P < 0.05) and ≤40% since the 15th day. Average microvessel density and EGFR expression in combined therapy group II were lower than radiotherapy group (P < 0.05). In vitro, the cell percentage in S and G2/M phase of combined therapy group cells was lower than that in radiotherapy group cells, while the apoptosis rate and the expression of VEGF, AKT, p-AKT, ERK1/2 and p-ERK1/2 in combined group were higher than that in radiotherapy group (P < 0.05).

CONCLUSIONS

RH-endostatin promotes the efficacy of radiotherapy on esophageal cancer, which may be partly realized by inhibiting the activity of VEGF related signal paths.

Blocking FGF2 with a new specific monoclonal antibody impairs angiogenesis and experimental metastatic melanoma, suggesting a potential role in adjuvant settings

Compelling evidence suggests that fibroblast growth factor 2 (FGF2), overexpressed in melanomas, plays an important role in tumor growth, angiogenesis and metastasis. In this study, we evaluated the therapeutic use of a new anti-FGF2 monoclonal antibody (mAb), 3F12E7, using for that the B16-F10 melanoma model. The FGF2 neutralizing effect of this antibody was certified by in vitro assays, which allowed the further track of its possible in vivo application. 3F12E7 mAb could be retained in B16-F10 tumors, as shown by antibody low-pH elution and nuclear medicine studies, and also led to reduction in number and size of metastatic foci in lungs, when treatment starts one day after intravenous injection of B16-F10 cells. Such data were accompanied by decreased CD34(+) tumor vascular density and impaired subcutaneous tumor outgrowth. Treatments starting one week after melanoma cell intravenous injection did not reduce tumor burden, remaining the therapeutic effectiveness restricted to early-adopted regimens. Altogether, the presented anti-FGF2 3F12E7 mAb stands as a promising agent to treat metastatic melanoma tumors in adjuvant settings.

Endostatin's emerging roles in angiogenesis, lymphangiogenesis, disease, and clinical applications

BACKGROUND

Angiogenesis is the process of neovascularization from pre-existing vasculature and is involved in various physiological and pathological processes. Inhibitors of angiogenesis, administered either as individual drugs or in combination with other chemotherapy, have been shown to benefit patients with various cancers. Endostatin, a 20-kDa C-terminal fragment of type XVIII collagen, is one of the most potent inhibitors of angiogenesis.

SCOPE OF REVIEW

We discuss the biology behind endostatin in the context of its endogenous production, the various receptors to which it binds, and the mechanisms by which it acts. We focus on its inhibitory role in angiogenesis, lymphangiogenesis, and cancer metastasis. We also present emerging clinical applications for endostatin and its potential as a therapeutic agent in the form a short peptide.

MAJOR CONCLUSIONS

The delicate balance between pro- and anti-angiogenic factors can be modulated to result in physiological wound healing or pathological tumor metastasis. Research in the last decade has emphasized an emerging clinical potential for endostatin as a biomarker and as a therapeutic short peptide. Moreover, elevated or depressed endostatin levels in diseased states may help explain the pathophysiological mechanisms of the particular disease.

GENERAL SIGNIFICANCE

Endostatin was once sought after as the 'be all and end all' for cancer treatment; however, research throughout the last decade has made it apparent that endostatin's effects are complex and involve multiple mechanisms. A better understanding of newly discovered mechanisms and clinical applications still has the potential to lead to future advances in the use of endostatin in the clinic.