In vitro and in vivo anti-angiogenic activities of Panduratin A

Zebrafish live imaging: a strong weapon in anticancer drug discovery and development

Developing anticancer drugs is a complex and time-consuming process. The inability of current laboratory models to reflect important aspects of the tumor in vivo limits anticancer medication research. Zebrafish is a rapid, semi-automated in vivo screening platform that enables the use of non-invasive imaging methods to monitor morphology, survival, developmental status, response to drugs, locomotion, or other behaviors. Zebrafish models are widely used in drug discovery and development for anticancer drugs, especially in conjunction with live imaging techniques. Herein, we concentrated on the use of zebrafish live imaging in anticancer therapeutic research, including drug screening, efficacy assessment, toxicity assessment, and mechanism studies. Zebrafish live imaging techniques have been used in numerous studies, but this is the first time that these techniques have been comprehensively summarized and compared side by side. Finally, we discuss the hypothesis of Zebrafish Composite Model, which may provide future directions for zebrafish imaging in the field of cancer research.

Phytochemicals Showing Antiangiogenic Effect in Pre-clinical Models and their Potential as an Alternative to Existing Therapeutics

Angiogenesis, the formation of new blood vessels from a pre-existing vascular network, is an important hallmark of several pathological conditions, such as tumor growth and metastasis, proliferative retinopathies, including proliferative diabetic retinopathy and retinopathy of prematurity, age-related macular degeneration, rheumatoid arthritis, psoriasis, and endometriosis. Putting a halt to pathology-driven angiogenesis is considered an important therapeutic strategy to slow down or reduce the severity of pathological disorders. Considering the attrition rate of synthetic antiangiogenic compounds from the lab to reaching the market due to severe side effects, several compounds of natural origin are being explored for their antiangiogenic properties. Employing pre-clinical models for the evaluation of novel antiangiogenic compounds is a promising strategy for rapid screening of antiangiogenic compounds. These studies use a spectrum of angiogenic model systems that include HUVEC two-dimensional culture, nude mice, chick chorioallantoic membrane, transgenic zebrafish, and dorsal aorta from rats and chicks, depending upon available resources. The present article emphasizes the antiangiogenic activity of the phytochemicals shown to exhibit antiangiogenic behavior in these well-defined existing angiogenic models and highlights key molecular targets. Different models help to get a quick understanding of the efficacy and therapeutics mechanism of emerging lead molecules. The inherent variability in assays and corresponding different phytochemicals tested in each study prevent their immediate utilization in clinical studies. This review will discuss phytochemicals discovered using suitable preclinical antiangiogenic models, along with a special mention of leads that have entered clinical evaluation.

Toward the use ofBoesenbergia rotundaextracts and the chalcone panduratin A to treat periodontitis

Novel affordable medications are needed to treat chronic periodontitis, which is one of the most common dental pathologies worldwide. Extracts prepared from the rhizome of the medicinal plant Boesenbergia rotunda (L.) Mansf., commonly known as fingerroot, are used to treat a variety of human pathologies. These extracts contain potent anti-inflammatory compounds, including the chalcone derivative panduratin A (Pa-A), which is the lead compound of a series of analogues, designated panduratins A to Y. The anti-inflammatory properties of the extracts of B. rotunda and the most abundant bioactive products found in these extracts (including Pa-A, 4-hydroxyoanduratin, isopanduratin, and others) have been reviewed. A standardized extract of the plant has promising utility in the treatment of gingival inflammation. The effects are characterized by three actions: (i) a direct antimicrobial effect against fungi and oral pathogens such as Porphyromonas gingivalis, (ii) a marked anti-inflammatory effect via a reduced production of mediators, like prostaglandin E2 and different interleukins, and (iii) a dual bone-preserving effect, with a reduction in bone resorption and an increase in bone formation. Acting as a protease inhibitor, Pa-A is one of the main active ingredients of the extract, implicated in these actions. A Pa-A-standardized extract of B. rotunda has been used in humans for treating dyspepsia. The product is safe and well-tolerated. The development of panduratin-containing dental products, for the prevention and treatment of periodontitis, has been proposed. The structural analogues, Pa-A to-Y, should also be investigated for the treatment of dental inflammation.

In Vitro and In Vivo Evaluation of a Cyclic LyP-1-Modified Nanosystem for Targeted Endostatin Delivery in a KYSE-30 Cell Xenograft Athymic Nude Mice Model

This work investigated the use of LyP-1 as a homing peptide for p32 receptor targeting on the surface of an endostatin (ENT)-loaded chitosan-grafted nanosystem intended for intracellular delivery of ENT and mitochondrial targeting in a squamous cell carcinoma (SCC) cell line (KYSE-30) model. The angiogenic factors for VEGF-C and MMP2 were assessed with in vivo evaluation of the nanosystem upon ENT release and tumor necrosis in nude mice with a KYSE-30 cell xenograft. The LyP-1-modified nanosystem revealed a three-fold decrease in proliferation at 1000 µg/mL compared with the control and facilitated receptor-mediated cellular uptake and internalization. In addition, targeting of the Lyp-1-functionalized nanosystem to mitochondrial and nuclear proteins in vitro and in vivo was achieved. Up to 60% inhibition of KYSE-30 cell migration was observed and the expressions of VEGF-C and MMP-2 as angiogenic markers were reduced 3- and 2-fold, respectively. A marked reduction in tumor mass was recorded (43.25%) with the control, a 41.36% decrease with the nanoparticles and a 61.01% reduction with the LyP-1-modified nanosystem following treatment in mice. The LyP-1-functionalized nanosystem targeted tumor lymphatics, instigated nuclear rupture and mitochondrial distortion, and decreased cell proliferation and migration with inhibition of VEGF-C and MMP2 expression.

Chalcone Scaffolds, Bioprecursors of Flavonoids: Chemistry, Bioactivities, and Pharmacokinetics

Chalcones are secondary metabolites belonging to the flavonoid (C6-C3-C6 system) family that are ubiquitous in edible and medicinal plants, and they are bioprecursors of plant flavonoids. Chalcones and their natural derivatives are important intermediates of the flavonoid biosynthetic pathway. Plants containing chalcones have been used in traditional medicines since antiquity. Chalcones are basically α,β-unsaturated ketones that exert great diversity in pharmacological activities such as antioxidant, anticancer, antimicrobial, antiviral, antitubercular, antiplasmodial, antileishmanial, immunosuppressive, anti-inflammatory, and so on. This review provides an insight into the chemistry, biosynthesis, and occurrence of chalcones from natural sources, particularly dietary and medicinal plants. Furthermore, the pharmacological, pharmacokinetics, and toxicological aspects of naturally occurring chalcone derivatives are also discussed herein. In view of having tremendous pharmacological potential, chalcone scaffolds/chalcone derivatives and bioflavonoids after subtle chemical modification could serve as a reliable platform for natural products-based drug discovery toward promising drug lead molecules/drug candidates.

Pro-Angiogenic and Osteogenic Effects of Adipose Tissue-Derived Pericytes Synergistically Enhanced by Nel-like Protein-1

An important objective of vascularized tissue regeneration is to develop agents for osteonecrosis. We aimed to identify the pro-angiogenic and osteogenic efficacy of adipose tissue-derived (AD) pericytes combined with Nel-like protein-1 (NELL-1) to investigate the therapeutic effects on osteonecrosis. Tube formation and cell migration were assessed to determine the pro-angiogenic efficacy. Vessel formation was evaluated in vivo using the chorioallantoic membrane assay. A mouse model with a 2.5 mm necrotic bone fragment in the femoral shaft was used as a substitute for osteonecrosis in humans. Bone formation was assessed radiographically (plain radiographs, three-dimensional images, and quantitative analyses), and histomorphometric analyses were performed. To identify factors related to the effects of NELL-1, analysis using microarrays, qRT-PCR, and Western blotting was performed. The results for pro-angiogenic efficacy evaluation identified synergistic effects of pericytes and NELL-1 on tube formation, cell migration, and vessel formation. For osteogenic efficacy analysis, the mouse model for osteonecrosis was treated in combination with pericytes and NELL-1, and the results showed maximum bone formation using radiographic images and quantitative analyses, compared with other treatment groups and showed robust bone and vessel formation using histomorphometric analysis. We identified an association between FGF2 and the effects of NELL-1 using array-based analysis. Thus, combinatorial therapy using AD pericytes and NELL-1 may have potential as a novel treatment for osteonecrosis.

The Chemopreventive Activity of Indonesia Medicinal Plants Targeting on Hallmarks of Cancer

Cancer remains a complex disease with increasing global mortality and morbidity. Numerous theories have been established to understand the biological mechanism underlying cancer. One of the most renowned frameworks is the hallmark of cancer proposed by Hanahan and Weinberg that covers ten eminent characteristics of cancer: (i) genome instability and mutation, (ii) sustaining proliferative signaling, (iii) evading growth suppressor, (iv) enabling replicative immortality, (v) resisting cell death, (vi) inducing angiogenesis, (vii) activating invasion and metastasis, (viii) avoiding immune destruction, (ix) tumor-promoting inflammation, and (x) deregulating cellular energetics. These hallmarks provide a rational approach to design an anticancer therapy. In the current review, we summarized specific target molecules on each hallmark of cancer. Further, we evaluated the biological activity of several Indonesia medicinal plants against those specific targets. We explicated the anticancer and chemopreventive activities of some medicinal plants that have been used for centuries by local communities in Indonesia, including Curcuma genus, Brucea javanica, Boesenbergia pandurata, Caesalpinia sappan, and Nigella sativa. Interestingly, these medicinal plants target several hallmarks of cancer, and even Curcuma genus exhibited biological activities that target all hallmarks of cancer. Further, we also discuss several strategies to develop those medicinal plants and/or their active compounds as anticancer and chemopreventive agents.

Hypoxia and matrix viscoelasticity sequentially regulate endothelial progenitor cluster-based vasculogenesis

Vascular morphogenesis is the formation of endothelial lumenized networks. Cluster-based vasculogenesis of endothelial progenitor cells (EPCs) has been observed in animal models, but the underlying mechanism is unknown. Here, using O₂-controllabe hydrogels, we unveil the mechanism by which hypoxia, co-jointly with matrix viscoelasticity, induces EPC vasculogenesis. When EPCs are subjected to a 3D hypoxic gradient ranging from <2 to 5%, they rapidly produce reactive oxygen species that up-regulate proteases, most notably MMP-1, which degrade the surrounding extracellular matrix. EPC clusters form and expand as the matrix degrades. Cell-cell interactions, including those mediated by VE-cadherin, integrin-β2, and ICAM-1, stabilize the clusters. Subsequently, EPC sprouting into the stiffer, intact matrix leads to vascular network formation. In vivo examination further corroborated hypoxia-driven clustering of EPCs. Overall, this is the first description of how hypoxia mediates cluster-based vasculogenesis, advancing our understanding toward regulating vascular development as well as postnatal vasculogenesis in regeneration and tumorigenesis.

Drynaria fortunei Promoted Angiogenesis Associated With Modified MMP-2/TIMP-2 Balance and Activation of VEGF Ligand/Receptors Expression

Background and Purpose:Drynaria fortunei J. Sm (D. fortunei), known as Gu-Sui-Bu, is used in traditional Chinese medicine to treat common injuries, including bone fractures and bruising. The specific functional mechanisms of the angiogenic and endothelial cell migration properties of D. fortunei are currently unclear. Thus, the purpose of this study is to validate the potential angiogenic and cellular migration properties and related mechanisms by D. fortunei both in vivo and in vitro.

Experimental Approach: The present study investigates, both in vivo and in vitro, the wound healing effects of D. fortunei as associated with angiogenesis, specifically by the modulation of matrix metalloproteinases (MMPs) and upregulation of vascular endothelial growth factor (VEGF) ligand/receptors. In order to determine the potential angiogenic effects of D. fortunei, in vivo neovascularization of chick chorioallantoic membranes (CAMs) assay, and directed in vivo angiogenesis assay (DIVVA) were performed, while in vitro scratch wound healing, migration, and matrix-induced tube formation assays were performed by using human umbilical vascular endothelial cells (HUVECs). Furthermore, we used qPCR to analyze the gene expressions and Western blot to observe protein expressions of MMP-2, MMP-14, TIMP-2, RECK, and VEGF/VEGFRs.

Results: This study identified five major compounds from the water extract of D. fortunei: protocatechuic acid, caffeic acid 4-O-β-D-glucopyranoside, 5,7-dihydroxychromone-7-O-rutinoside, neoeriocitrin, and naringin. D. fortunei was confirmed to activate in vivo angiogenesis by CAM and DIVVA assays. D. fortunei further exhibited in vitro angiogenic effects associated with cell migration, as demonstrated by the tube formation assay, transwell migration assay, and scratch wound healing assay. The extracellular MMP-2 activity was found to be dose-dependently augmented both in vitro and in vivo by D. fortunei. The mRNA and protein expressions of MMP-2, and MMP-14 were increased; while the tissue inhibitor metalloproteinase-2 (TIMP-2), and reversion-inducing cysteine-rich protein with kazal motifs (RECK) were both decreased. Furthermore, D. fortunei activated the gene and protein expressions of VEGF-A, -B, and VEGFR-2, -3.

Conclusion:D. fortunei increased MMP-2 activity, thereby stimulating angiogenesis and cell migration, both in vivo and in vitro, as a result of MMP-2 and TIMP-2 balance modulation and the activation of VEGF/VEGFRs expression.

Hepatoprotectivity of Panduratin A against liver damage: In vivo demonstration with a rat model of cirrhosis induced by thioacetamide

This experiment evaluated Panduratin A (PA), a chalcone isolated from Boesenbergia rotunda rhizomes, for its hepatoprotectivity. Rats were subjected to liver damage induced by intra-peritoneal injection of thioacetamide (TAA). PA was tested first for its acute toxicity and then administered by oral gavage at doses 5, 10, and 50 mg/kg to rats. At the end of the 8^th week, livers from all rats were excised and evaluated ex vivo. Measurements included alkaline phosphatase (AP), alanine transaminase (ALT), aspartate transaminase (AST) and gamma-glutamyl transferase (GGT), serum platelet-derived growth factor (PDGF) and transforming growth factor (TGF-β1), and hepatic metalloproteinase enzyme (MMP-2) and its inhibitor extracellular matrix protein (TIMP-1). Oxidative stress was measured by liver malondialdehyde (MDA) and nitrotyrosine levels, urinary 8-hydroxy 2- deoxyguanosine (8-OH-dG), and hepatic antioxidant enzyme activities. The immunohistochemistry of TGF-β₁ was additionally performed. PA revealed safe dose of 250 mg/kg on experimental rats and positive effect on the liver. The results suggested reduced hepatic stellate cells (HSCs) activity as verified from the attenuation of serum PDGF and TGF-β1, hepatic MMP-2 and TIMP-1, and oxidative stress. The extensive data altogether conclude that PA treatment could protect the liver from the progression of cirrhosis through a possible mechanism inhibiting HSCs activity.

Panduratin A induces protective autophagy in melanoma via the AMPK and mTOR pathway

BACKGROUND

Targeting autophagy is emerging as a promising strategy in cancer therapeutics in recent years. Autophagy can be modulated to drive cancer cell deaths that are notoriously resistant to apoptotic-inducing drugs. In addition, autophagy has been implicated as a prosurvival mechanism in mediating cancer chemoresistance. Our previous study has demonstrated that Panduratin A (PA), a plant-derived active compound exploits ER-stress-mediated apoptosis as its cytotoxic mechanism on melanoma.

PURPOSE

Our previous proteomics analysis revealed that treatment with PA resulted in the upregulation of an autophagy marker, LC3B in melanoma cells. Therefore, the present study sought to investigate the role of PA-induced autophagy in melanoma cells.

METHODS

Transmission electron microscopy was performed for examination of autophagic ultra-structures in PA-treated A375 cells. Cytoplasmic LC3B and p62/SQSMT1 punctate structures were detected using immunofluorescene staining. Expression levels of LC3B II, p62/SQSMT1, ATG 12, Beclin 1, phospho S6 (ser235/236), phospho AMPK (Thr172) and cleaved PARP were evaluated by western blotting.

RESULTS

Autophagosomes, autolysosomes and punctuates of LC3 proteins could be observed in PA-treated A375 cells. PA-induced autophagy in A375 melanoma cells was found to be mediated through the inhibition of mTOR signaling and activation of AMPK pathway. Furthermore, we showed that PA-induced apoptosis was increased in the presence of an autophagy inhibitor, signifying the cytoprotective effect of PA-induced autophagy in melanoma cells.

CONCLUSION

Taken together, results from the present study suggest that the inhibition of autophagy by targeting mTOR and AMPK could potentiate the cytotoxicity effects of PA on melanoma cells.

Antiangiogenic Effect of Flavonoids and Chalcones: An Update

Chalcones are precursors of flavonoid biosynthesis in plants. Both flavonoids and chalcones are intensively investigated because of a large spectrum of their biological activities. Among others, anticancer and antiangiogenic effects account for the research interest of these substances. Because of an essential role in cancer growth and metastasis, angiogenesis is considered to be a promising target for cancer treatment. Currently used antiangiogenic agents are either synthetic compounds or monoclonal antibodies. However, there are some limitations of their use including toxicity and high price, making the search for new antiangiogenic compounds very attractive. Nowadays it is well known that several natural compounds may modulate basic steps in angiogenesis. A lot of studies, also from our lab, showed that phytochemicals, including polyphenols, are potent modulators of angiogenesis. This review paper is focused on the antiangiogenic effect of flavonoids and chalcones and discusses possible underlying cellular and molecular mechanisms.

Anti-Proliferative Activity and Apoptosis Induction of an Ethanolic Extract of Boesenbergia pandurata (Roxb.) Schlecht. against HeLa and Vero Cell Lines

Rhizomes of Boesenbergia pandurata (Roxb.) Schlecht have been reported to contain active compounds with anticancer properties. This research was carried out to examine anti-proliferative and apoptotic induction against HeLa and Vero cells-line. Dried powder of B. pandurata rhizomes was extracted by a maceration method using 90% ethanol. Cytotoxic assays to determine IC50 and anti-proliferative effects were carried out by MTT methods. Observation of apoptosis was achieved with double staining using acridine orange and ethidium bromide. The results showed that ethanolic extract of B. pandurata was more cytotoxic against HeLa cells (IC50 of 60 μg/ mL) than Vero cells (IC50 of 125 μg/mL). The extract had higher anti-proliferative activity as well as apoptotic induction in HeLa than Vero cells. Therefore, it was concluded that the ethanolic extract of B. pandurata had anti-proliferative as well as apoptosis induction activity dependent on the cell type.

Vastatin, an Endogenous Antiangiogenesis Polypeptide That Is Lost in Hepatocellular Carcinoma, Effectively Inhibits Tumor Metastasis

Hepatocellular carcinoma (HCC) is a hypervascular cancer without effective treatment. Here we report that polypeptide of NC1 domain of type VIII collagen (Vastatin) is an endogenous polypeptide expressed in normal liver tissue but lost in the liver of most HCC patients (73.1%). Its expression level is negatively associated with tumor size (P = 0.035) and metastasis (P = 0.016) in HCC patients. To evaluate its potential use as a therapeutic, we constructed a recombinant adeno-associated virus carrying Vastatin (rAAV-Vastatin) to treat HCC in an orthotopic Buffalo rat model. rAAV-Vastatin treatment significantly prolonged the median survival, inhibited tumor growth, and completely prevented metastasis in HCC-bearing rats by decreasing microvessel density and increasing tumor necrosis. No detectable toxicity in nontumor-bearing mice was observed. To investigate its molecular mechanisms, we performed DNA microarray, western blotting assays, and bioinformatic analysis to determine its effect on global gene expression patterns and signal transduction pathways. Our results indicated that rAAV-Vastatin significantly reduced the expressions of Pck1, JAG2, and c-Fos, thus inhibiting the cellular metabolism, Notch and AP-1 signaling pathways, respectively. Hence, we demonstrated for the first time that Vastatin is a novel, safe, and effective antiangiogenic therapeutic and a potential biomarker for HCC.

Sprouting Buds of Zebrafish Research in Malaysia: First Malaysia Zebrafish Disease Model Workshop

Zebrafish is gaining prominence as an important vertebrate model for investigating various human diseases. Zebrafish provides unique advantages such as optical clarity of embryos, high fecundity rate, and low cost of maintenance, making it a perfect complement to the murine model equivalent in biomedical research. Due to these advantages, researchers in Malaysia are starting to take notice and incorporate the zebrafish model into their research activities. However, zebrafish research in Malaysia is still in its infancy stage and many researchers still remain unaware of the full potential of the zebrafish model or have limited access to related tools and techniques that are widely utilized in many zebrafish laboratories worldwide. To overcome this, we organized the First Malaysia Zebrafish Disease Model Workshop in Malaysia that took place on 11th and 12th of November 2015. In this workshop, we showcased how the zebrafish model is being utilized in the biomedical field in international settings as well as in Malaysia. For this, notable international speakers and those from local universities known to be carrying out impactful research using zebrafish were invited to share some of the cutting edge techniques that are used in their laboratories that may one day be incorporated in the Malaysian scientific community.

A cystine-knot miniprotein from tomato fruit inhibits endothelial cell migration and angiogenesis by affecting vascular endothelial growth factor receptor (VEGFR) activation and nitric oxide production

SCOPE

Cystine-knot miniproteins are bioactive molecules with a broad range of potential therapeutic applications. Recently, it was demonstrated that two tomato cystine-knot miniproteins (TCMPs) exhibit in vitro antiangiogenic activity on human umbilical vein cells. The aim of the present study was to investigate the effects of a fruit-specific cystine-knot miniprotein of tomato on in vitro endothelial cell migration and in vivo angiogenesis using a zebrafish model.

METHODS AND RESULTS

The cystine-knot protein purified from tomato fruits using gel filtration LC and RP-HPLC inhibited cell migration when tested at 200 nM using the wound healing assay, and reduced nitric oxide formation probed by 4-amino-5-methylamino-27-difluorofluoscescin diacetate. RT-PCR and Western blot analyses demonstrated that vascular endothelium growth factor A dependent signaling was the target of TCMP bioactivity. Angiogenesis was inhibited in vivo in zebrafish embryos treated with 500 nM TCMP.

CONCLUSION

Our results demonstrate that cystine-knot miniproteins present in mature tomato fruits are endowed with antiangiogenic activity in vitro and in vivo. These molecules may confer beneficial effects to tomato dietary intake, along with lycopene and other antioxidants. Further investigation is warranted to explore the potential of these compounds as model scaffolds for the development of new drugs.

In vitro and in vivo anti-angiogenic activity of girinimbine isolated from Murraya koenigii

Girinimbine is a carbazole alkaloid isolated from the stem bark and root of Murraya koenigii. Here we report that girinimbine is an inhibitor of angiogenic activity both in vitro and in vivo. MTT results showed that girinimbine inhibited proliferation of human umbilical vein endothelial cells, while results from endothelial cell invasion, migration, tube formation, and wound healing assays demonstrated significant time- and dose-dependent inhibition by girinimbine. A proteome profiler array done on girinimbine-treated human umbilical vein endothelial cells showed that girinimbine had mediated regulation of pro-angiogenic and anti-angiogenic proteins. The anti-angiogenic potential of girinimbine was also evidenced in vivo in the zebrafish embryo model wherein girinimbine inhibited neo vessel formation in zebrafish embryos following 24 hours of exposure. Together, these results showed that girinimbine could effectively suppress angiogenesis, suggestive of its therapeutic potential as a novel angiogenesis inhibitor.

Total saponins from Albizia julibrissin inhibit vascular endothelial growth factor-mediated angiogenesis in vitro and in vivo

Dried stem bark from Albizia julibrissin (AJ) is a highly valued Traditional Chinese Medicine, which has been shown to suppress tumor growth and angiogenesis. Total saponins from AJ (TSAJ) are one of the most bioactive components of AJ extract. The present study evaluated the anti-tumor and anti-angiogenic effects of TSAJ in vitro and in vivo. The anti-angiogenic activity of TSAJ was investigated by measuring the effects on vascular endothelial growth factor (VEGF)-induced proliferation, migration and tube formation of Ea.hy926 endothelial cells in vitro. The expression levels of proteins associated with VEGF-induced angiogenesis were determined by western blotting. Furthermore, in vivo Matrigel™ plug and H22 hepatoma tumor models were used to verify the anti-angiogenic effects of TSAJ. The present study demonstrated that TSAJ significantly inhibited VEGF-mediated endothelial cell proliferation, migration and tube formation of Ea.hy926 cells in vitro. The anti-angiogenic effects of TSAJ were modulated by suppression of phosphorylated-(p-) focal adhesion kinase, p-Akt, and p-extracellular signal-regulated kinase in the VEGF/VEGF receptor 2 (R2) signaling pathway. Furthermore, oral administration of TSAJ significantly inhibited tumor growth and tumor-induced angiogenesis, as well as the formation of functional vessels, in the Matrigel™ plug model. These results suggest that TSAJ may be a potential anti-angiogenic agent that targets the VEGF/VEGFR2 signaling pathway, and inhibits tumor-induced angiogenesis.

iTRAQ-based proteomic identification of proteins involved in anti-angiogenic effects of Panduratin A on HUVECs

Panduratin A (PA), a cyclohexanyl chalcone from Boesenbergia rotunda (L.) Mansf. was shown to possess anti-angiogenic effects in our previous study. In the present study, the molecular targets and anti-angiogenic mechanisms of PA on human umbilical vein endothelial cells (HUVECs) were identified using an iTRAQ-based quantitative proteomics approach. A total of 263 proteins were found to be differentially regulated in response to treatment with PA. Ingenuity Pathway Analysis revealed that cellular growth and proliferation, protein synthesis, RNA post-transcriptional modification, cellular assembly and organization and cell-to-cell signaling and interaction were the most significantly deregulated molecular and cellular functions in PA-treated HUVECs. PA inhibited the expressions of ARPC2 and CTNND1 that are associated with the formation of actin cytoskeleton, focal adhesion and cellular protrusions. In addition, PA down-regulated CD63, GRB-2, ICAM-2 and STAB-1 that are implicated in adhesion, migration and tube formation of endothelial cells. The differential expressions of three targets, namely, ARPC2, CDK4, and GRB-2 were validated by western blot analyses. Furthermore, PA inhibited G1-S progression, and resulted in G0/G1 arrest in HUVECs. The blockage in cell cycle progression was accompanied with the suppression of mTOR signaling. Treatment of HUVECs with PA resulted in decreased phosphorylation of ribosomal S6 and 4EBP1 proteins, the two downstream effectors of mTOR signaling. We further showed that PA is able to inhibit mTOR signaling induced by VEGF, a potent inducer of angiogenesis. Taken together, by integrating quantitative proteomic approach, we identified protein targets in which PA mediates its anti-angiogenic effects. The present study thus provides mechanistic evidence to the previously reported multifaceted anti-angiogenic effects of PA. Our study further identified mTOR signaling as an important target of PA, and therefore highlights the potential of PA for therapeutic intervention against angiogenesis-related pathogenesis, particularly, metastatic malignancy.

Antivascular and anti-parasite activities of natural and hemisynthetic flavonoids from New Caledonian Gardenia species (Rubiaceae)

A series of 16 flavonoids were isolated and prepared from bud exudate of Gardenia urvillei and Gardenia oudiepe, endemic to New Caledonia. Most of them are rare polymethoxylated flavones. Some of these compounds showed noticeable activity against Leishmania (Leishmania) amazonensis, Plasmodium falciparum and Trypanosoma brucei gambiense, in addition to tubulin polymerization inhibition at low micromolar concentration. We also provide a full set of NMR data as some of the flavones were incompletely described.

Endostar, a modified recombinant human endostatin, suppresses angiogenesis through inhibition of Wnt/β-catenin signaling pathway

Endostar, a novel modified recombinant human endostatin, is now widely studied for the treatment of diseases that are characterized or caused by pathological angiogenesis. However, its molecular mechanism remains unclear. In this study, we investigated the effects of Endostar on the Wnt/β-catenin signaling pathway, which has emerged as an important aspect of angiogenesis. We showed that Endostar significantly inhibited the proliferation, migration, invasion, and capillary-like tube formation of human umbilical vascular endothelial cells in a dose-dependent manner. Using a luciferase reporter assay, we also demonstrated that Endostar suppressed β-catenin-dependent T cell factor transcriptional activity in increasing doses. Moreover, we found that Endostar treatment also restricted the stabilized mutant β-catenin-mediated increase in transcriptional activity, suggesting that Endostar exerts its inhibitory influence on Wnt/β-catenin signaling by targeting β-catenin or its downstream molecules. Western blot and immunofluorescence results revealed that Endostar significantly decreased nuclear and total β-catenin levels. Finally, we discovered that Endostar down-regulated cyclin D1 and VEGF, two proteins that are known as the downstream targets of Wnt/β-catenin signaling and that also play important roles in angiogenesis. Our findings suggested that Endostar inhibits angiogenesis and that the downregulation of the Wnt/β-catenin signaling pathway may be involved in the inhibition of angiogenesis by Endostar. These results support the use of Endostar in further clinical applications.

Synthesis and mechanistic studies of a novel homoisoflavanone inhibitor of endothelial cell growth

Preventing pathological ocular angiogenesis is key to treating retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration. At present there is no small molecule drug on the market to target this process and hence there is a pressing need for developing novel small molecules that can replace or complement the present surgical and biologic therapies for these neovascular eye diseases. Previously, an antiangiogenic homoisoflavanone was isolated from the bulb of a medicinal orchid, Cremastra appendiculata. In this study, we present the synthesis of a novel homoisoflavanone isomer of this compound. Our compound, SH-11052, has antiproliferative activity against human umbilical vein endothelial cells, and also against more ocular disease-relevant human retinal microvascular endothelial cells (HRECs). Tube formation and cell cycle progression of HRECs were inhibited by SH-11052, but the compound did not induce apoptosis at effective concentrations. SH-11052 also decreased TNF-α induced p38 MAPK phosphorylation in these cells. Intriguingly, SH-11052 blocked TNF-α induced IκB-α degradation, and therefore decreased NF-κB nuclear translocation. It decreased the expression of NF-κB target genes and the pro-angiogenic or pro-inflammatory markers VCAM-1, CCL2, IL8, and PTGS2. In addition SH-11052 inhibited VEGF induced activation of Akt but not VEGF receptor autophosphorylation. Based on these results we propose that SH-11052 inhibits inflammation induced angiogenesis by blocking both TNF-α and VEGF mediated pathways, two major pathways involved in pathological angiogenesis. Synthesis of this novel homoisoflavanone opens the door to structure-activity relationship studies of this class of compound and further evaluation of its mechanism and potential to complement existing antiangiogenic drugs.

A murine-human chimeric IgG antibody against vascular endothelial growth factor receptor 2 inhibits angiogenesis in vitro

Vascular endothelial growth factor receptor 2 (VEGFR2) has been reported to play an important role in angiogenesis and tumorigenesis. A murine anti-VEGFR2 mAb (A8H1) has been established in a previous study. To reduce the incompatibility of the murine mAb for human use, the chimeric anti-VEGFR2-IgG was developed by genetic recombination of the variable regions of the A8H1 antibody and the constant regions of human IgG, and was expressed in Sp2/0 cells transfected with the two recombinant vectors containing the heavy chain and the light chain regions. After screening, clone 2F12 was selected and was found to stably secrete the murine-human chimeric anti-VEGFR2-IgG (coded 2F12). This chimeric IgG maintained the specificity and the affinity of the parental murine antibody against VEGFR2, and effectively identified VEGFR2 expressed on the surface of HUVECs and BEL-7402 cells. Furthermore, the 2F12 antibody demonstrated inhibition of angiogenesis in vitro, such as proliferation, migration, invasion and tube formation of HUVECs. This murine-human chimeric IgG may be considered for further development as an anti-angiogenesis and anti-tumor agent.

Panduratin A, a possible inhibitor in metastasized A549 cells through inhibition of NF-kappa B translocation and chemoinvasion

In the present study, we investigated the effects of panduratin A (PA), isolated from Boesenbergia rotunda, on apoptosis and chemoinvasion in A549 human non-small cell lung cancer cells. Activation of the executioner procaspase-3 by PA was found to be dose-dependent. Caspase-3 activity was significantly elevated at the 5 µg/mL level of PA treatment and progressed to a maximal level. However, no significant elevated level was detected on procaspase-8. These findings suggest that PA activated caspase-3 but not caspase-8. Numerous nuclei of PA treated A549 cells stained brightly by anti-cleaved PARP antibody through High Content Screening. This result further confirmed that PA induced apoptotic cell death was mediated through activation of caspase-3 and eventually led to PARP cleavage. Treatment of A549 cells with PA resulted in a strong inhibition of NF-κB activation, which was consistent with a decrease in nuclear levels of NF-κB/p65 and NF-κB/p50 and the elevation of p53 and p21. Besides that, we also showed that PA significantly inhibited the invasion of A549 cells in a dose-dependent manner through reducing the secretion of MMP-2 of A549 cells gelatin zymography assay. Our findings not only provide the effects of PA, but may also be important in the design of therapeutic protocols that involve targeting of either p53 or NF-κB.

Butein Inhibits Angiogenesis of Human Endothelial Progenitor Cells via the Translation Dependent Signaling Pathway

Compelling evidence indicates that bone marrow-derived endothelial progenitor cells (EPCs) can contribute to postnatal neovascularization and tumor angiogenesis. EPCs have been shown to play a "catalytic" role in metastatic progression by mediating the angiogenic switch. Understanding the pharmacological functions and molecular targets of natural products is critical for drug development. Butein, a natural chalcone derivative, has been reported to exert potent anticancer activity. However, the antiangiogenic activity of butein has not been addressed. In this study, we found that butein inhibited serum- and vascular endothelial growth factor- (VEGF-) induced cell proliferation, migration, and tube formation of human EPCs in a concentration dependent manner without cytotoxic effect. Furthermore, butein markedly abrogated VEGF-induced vessels sprouting from aortic rings and suppressed microvessel formation in the Matrigel implant assay in vivo. In addition, butein concentration-dependently repressed the phosphorylation of Akt, mTOR, and the major downstream effectors, p70S6K, 4E-BP1, and eIF4E in EPCs. Taken together, our results demonstrate for the first time that butein exhibits the antiangiogenic effect both in vitro and in vivo by targeting the translational machinery. Butein is a promising angiogenesis inhibitor with the potential for treatment of cancer and other angiogenesis-related diseases.

Artemether combined with shRNA interference of vascular cell adhesion molecule-1 significantly inhibited the malignant biological behavior of human glioma cells

Artemether is the derivative extracted from Chinese traditional herb and originally used for malaria. Artemether also has potential therapeutic effects against tumors. Vascular cell adhesion molecule-1 (VCAM-1) is an important cell surface adhesion molecule associated with malignancy of gliomas. In this work, we investigated the role and mechanism of artemether combined with shRNA interference of VCAM-1 (shRNA-VCAM-1) on the migration, invasion and apoptosis of glioma cells. U87 human glioma cells were treated with artemether at various concentrations and shRNA interfering technology was employed to silence the expression of VCAM-1. Cell viability, migration, invasiveness and apoptosis were assessed with MTT, wound healing, Transwell and Annexin V-FITC/PI staining. The expression of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) and phosphorylated Akt (p-Akt) was checked by Western blot assay. Results showed that artemether and shRNA-VCAM-1 not only significantly inhibited the migration, invasiveness and expression of MMP-2/9 and p-Akt, but also promoted the apoptosis of U87 cells. Combined treatment of both displayed the maximum inhibitory effects on the malignant biological behavior of glioma cells. Our work revealed the potential therapeutic effects of artemether and antiVCAM-1 in the treatments of gliomas.