Green tea catechin inhibits ephrin-A1-mediated cell migration and angiogenesis of human umbilical vein endothelial cells

Recent advances of the Ephrin and Eph family in cardiovascular development and pathologies

Erythropoietin-producing hepatoma (Eph) receptors, comprising the largest family of receptor tyrosine kinases (RTKs), exert profound influence on diverse biological processes and pathological conditions such as cancer. Interacting with their corresponding ligands, erythropoietin-producing hepatoma receptor interacting proteins (Ephrins), Eph receptors regulate crucial events like embryonic development, tissue boundary formation, and tumor cell survival. In addition to their well-established roles in embryonic development and cancers, emerging evidence highlights the pivotal contribution of the Ephrin/Eph family to cardiovascular physiology and pathology. Studies have elucidated their involvement in cardiovascular development, atherosclerosis, postnatal angiogenesis, and, more recently, cardiac fibrosis and calcification, suggesting a promising avenue for therapeutic interventions in cardiovascular diseases. There remains a need for a comprehensive synthesis of their collective impact in the cardiovascular context. By exploring the intricate interactions between Eph receptors, ephrins, and cardiovascular system, this review aims to provide a holistic understanding of their roles and therapeutic potential in cardiovascular health and diseases.

Increased Serum EphrinA1 Is Associated with Parenchymal Hematoma after Ischemic Stroke

INTRODUCTION

Previous preclinical studies reported that the level of serum EphrinA1 was associated with blood-brain barrier disruption; however, its role in predicting parenchymal hematoma (PH) after ischemic stroke is underexplored. We aimed to explore the association between the level of serum EphrinA1 and PH in patients with ischemic stroke.

METHODS

Patients with ischemic stroke after onset from West China Hospital, Sichuan University, were prospectively enrolled between January 2017 and December 2019. The level of serum EphrinA1 at baseline was measured after admission. PH was diagnosed as hematoma within the infarct territory detected on the brain CT/MRI scans within 7 days after onset but not on the initial scan according to European Cooperative Acute Stroke Study (ECASS) III criteria. The association between the level of serum EphrinA1 and PH after ischemic stroke was assessed by multiple logistic regression analysis.

RESULTS

A total of 667 patients were included in the final analysis. The mean age was 67.20 ± 14.31 years, and 57.87% (368/667) were males. Of the 667 patients, 65 (9.75%) patients had PH. The median of EphrinA1 on admission was 82.83 ng/mL (IQR, 70.11-93.75 ng/mL). Compared with patients without PH, those with PH had a higher level of serum EphrinA1 (p = 0.024). Patients were divided into 3 categories based on EphrinA1 tertiles (T1, <79.11 ng/mL, n = 223; T2, 79.11-93.75 ng/mL, n = 222; and T3, >93.75 ng/mL, n = 222). After adjusting for age, sex, atrial fibrillation, smoking, statins, antiplatelets, Trail of Org 10172 in Acute Stroke Treatment (TOAST) classification and National Institutes of Health Stroke Scale (NIHSS) score ≥15, patients in the second and third EphrinA1 tertiles showed a significant increase in PH compared with those in the lowest tertile (OR 2.44, 95% CI: 1.10-5.40, p = 0.028; OR 2.61, 95% CI: 1.19-5.74, p = 0.017, respectively). Additionally, adjusting for reperfusion therapy (thrombolysis and/or endovascular therapy), only patients in the highest group (tertile 3) had a significantly higher risk of PH compared to the lowest group (OR 2.30, 95% CI: 1.03-5.13, p = 0.042).

CONCLUSION

Higher serum EphrinA1 is independently associated with a higher risk of PH after ischemic stroke. Future studies with larger sample sizes are needed to validate our findings and elucidate the potential role of EphrinA1 in PH.

Chimonanthus salicifolius attenuated vascular remodeling by alleviating endoplasmic reticulum stress in spontaneously hypertensive rats

Chimonanthus salicifolius (CS), the leaves of Chimonanthus salicifolius S. Y. Hu., is an effective tea to prevent and treat hypertension in China. This study aimed to explore the effect and mechanism of CS in the protection against vascular remodeling in hypertension. Spontaneously hypertensive rats (SHRs) were orally administered with aqueous extracts of CS for 6 months. The blood pressure and morphological changes of the aorta were measured. Their mechanisms were studied by combining chemical identification, network pharmacology analysis and validation in vivo. Hypertensive rats showed an impaired vascular structure and dyslipidemia as illustrated by the increase of the vascular media thickness and collagen deposition in the aorta. CS treatment exhibited significant beneficial effects on blood pressure control and aortal morphology. A total of 21 compounds from CS were identified, which were linked to 106 corresponding targeted genes for vascular remodeling. The network pharmacology predicted that CS prevented vascular remodeling through the endoplasmic reticulum stress pathway. The in vivo experiments further showed that CS treatment upregulated Glucose-Regulated Protein 78 and downregulated CCAAT-enhancer-binding protein homologous protein at both mRNA and protein levels, paralleling reduced apoptotic cells in the arterial wall. Additionally, CS diminished the low-density lipoprotein cholesterol levels, total cholesterol contents and triglyceride/high-density lipoprotein cholesterol ratios in the sera of SHRs, which might also contribute to its protection of vessels. Collectively, CS protects against vascular modeling by suppressing endoplasmic reticulum stress-related apoptosis in hypertension, and it could be a potential agent for the prevention and treatment of vascular modeling.

EFNA1 in gastrointestinal cancer: Expression, regulation and clinical significance

Ephrin-A1 is a protein that in humans is encoded by the EFNA1 gene. The ephrins and EPH-related receptors comprise the largest subfamily of receptor protein-tyrosine kinases which play an indispensable role in normal growth and development or in the pathophysiology of various tumors. The role of EFNA1 in tumorigenesis and development is complex and depends on the cell type and microenvironment which in turn affect the expression of EFNA1. This article reviews the expression, prognostic value, regulation and clinical significance of EFNA1 in gastrointestinal tumors.

Distribution of polyphenolic compounds, antioxidant potential, and free amino acids in Ziziphus fruits extract; a study for determining the influence of wider geography

Ziziphus fruits have attracted much attention within the field of medicine due to their high potential against central nervous system disorders. Abundance of secondary metabolites and their composition is key to the pharmaceutical potential and commercial qualities of plants. The in vitro antioxidant activities of Ziziphus nummularia (Burm. f.) and Ziziphus oxyphylla Edgew fruit extract were analyzed using 2,2‐diphenil‐1‐pycrilhydrazyl (DPPH) and 2,2′‐azino‐bis (3‐ethylbenzothiazoline)‐6‐sulfonic acid (ABTS) free radical scavenging assay methods. Phenolic profiles were explored using high‐performance liquid chromatography‐diode array detector (HPLC‐DAD). The result revealed high concentration of polyphenols and their antioxidant potential. In Z. nummularia, the total phenolic content (TPC) (80.270 ± 0.422 μg/ml), DPPH (62.03 ± 0.98 μg/ml), ABTS (66.32 ± 0.73 μg/ml), and TFC (90.683 ± 0.274 μg/ml) were recorded. However, in Z. oxyphylla, DPPH and ABTS values were 60.66 ± 0.56 μg/ml and 61.55 ± 0.77 μg/ml, respectively, indicative of the impacts of climate and soil nutrients. The overall screening of phytochemicals revealed that both the Ziziphus species contain diverse bioactive compounds, including spinacetine‐3‐O‐(2 feruloyl glucopyranosyl)‐glucopyranoside, kaempferol‐3‐O‐glucoside‐7‐O‐glucoside, and caffeic acid; p‐hydroxybenzoyl hexose, p‐coumaric acid, salicylic acid, and ellagic acid pentoxide. Additionally, the highest concentrated amino acid noted was of Lue 0.19 g/100 g with 596.00 retention time (RT), followed by Thr>Ale>Isl>Phya>Val in Z. nummularia. Similarly, the highest concentration of Lue amino acid was recorded as 0.18/100 g with 564.52 RT followed by Pr>Thr>Ale>Lue>Isl>Phya>Val in all genotypes of Z. oxyphylla. Reporting of polyphenols rich and stable species along with identification of favorable regions of cultivation for amino acid, polyphenols, and higher antioxidant potential may lead the way for the identification of elite clones of the species as well as may result in new drug discovery.

Structure of Some Green Tea Catechins and the Availability of Intracellular Copper Influence Their Ability to Cause Selective Oxidative DNA Damage in Malignant Cells

The possible roles of elevated endogenous copper levels in malignant cells are becoming increasingly understood at a greater depth. Our laboratory has previously demonstrated that tea catechins have the ability to mobilize endogenous copper and undergo a Fenton-like reaction that can selectively damage cancer cells. In this communication, by using a diverse panel of malignant cell lines, we demonstrate that the ability of the catechin family [(−)-epigallocatechin-3-gallate (EGCG), (−)-epigallocatechin (EGC), (−)-epicatechin (EC), and (+)-catechin (C)] to induce apoptosis is dependent on their structure. We further confirm that reactive oxygen species (ROS) are the terminal effectors causing copper-mediated DNA damage. Our studies demonstrate the role of cellular copper transporters CTR1 and ATP7A in the survival dynamics of malignant cells post-EGCG exposure. The results, when considered together with our previous studies, highlight the critical role that copper dynamics and mobilization plays in cancer cells and paves the way for a better understanding of catechins as nutraceutical supplements for malignancies.

Cholenic acid derivative UniPR1331 impairs tumor angiogenesis via blockade of VEGF/VEGFR2 in addition to Eph/ephrin

Angiogenesis, the formation of new blood vessels from preexisting ones, is crucial for tumor growth and metastatization, and is considered a promising therapeutic target. Unfortunately, drugs directed against a specific proangiogenic growth factor or receptor turned out to be of limited benefit for oncology patients, likely due to the high biochemical redundancy of the neovascularization process. In this scenario, multitarget compounds that are able to simultaneously tackle different proangiogenic pathways are eagerly awaited. UniPR1331 is a 3β-hydroxy-Δ⁵-cholenic acid derivative, which is already known to inhibit Eph-ephrin interaction. Here, we employed an analysis pipeline consisting of molecular modeling and simulation, surface plasmon resonance spectrometry, biochemical assays, and endothelial cell models to demonstrate that UniPR1331 directly interacts with the vascular endothelial growth factor receptor 2 (VEGFR2) too. The binding of UniPR1331 to VEGFR2 prevents its interaction with the natural ligand vascular endothelial growth factor and subsequent autophosphorylation, signal transduction, and in vitro proangiogenic activation of endothelial cells. In vivo, UniPR1331 inhibits tumor cell-driven angiogenesis in zebrafish. Taken together, these data shed light on the pleiotropic pharmacological effect of UniPR1331, and point to Δ⁵-cholenic acid as a promising molecular scaffold for the development of multitarget antiangiogenic compounds.

Nutraceuticals and their role in tumor angiogenesis

Angiogenesis plays a pivotal role in cancer initiation, maintenance, and progression. Diet may inhibit, retard or reverse these processes affecting angiogenesis (angioprevention). Nutraceuticals, such as omega-3 fatty acids, amino acids, proteins, vitamins, minerals, fibers, and phenolic compounds, improve health benefits as they are a source of bioactive compounds that, among other effects, can regulate angiogenesis. The literature concerning the pro-angiogenic and/or anti-angiogenic nutraceuticals and the possible activated pathways in cancer and other non-neoplastic diseases by in vivo and in vitro experiments are reviewed.

Effects of 6,8-Diprenylgenistein on VEGF-A-Induced Lymphangiogenesis and Lymph Node Metastasis in an Oral Cancer Sentinel Lymph Node Animal Model

BACKGROUND

The major determining factor of prognosis of oral squamous cell carcinoma is cervical lymph node metastasis. 6,8-Diprenylgenistein (6,8-DG), an isoflavonoid isolated from Cudrania tricuspidata has been reported to have anti-microbial and anti-obesity activities. However, its effects on lymphangiogenesis and lymph node metastasis in oral cancer have not yet been reported.

METHODS

To investigate the in vitro inhibitory effects of 6,8-DG on VEGF-A-induced lymphangiogenesis, we performed the proliferation, tube formation, and migration assay using human lymphatic microvascular endothelial cells (HLMECs). RT-PCR, Western blot, immunoprecipitation, ELISA and co-immunoprecipitation assays were used to investigate the expression levels of proteins, and mechanism of 6,8-DG. The in vivo inhibitory effects of 6,8-DG were investigated using an oral cancer sentinel lymph node (OCSLN) animal model.

RESULTS

6,8-DG inhibited the proliferation, migration and tube formation of rhVEGF-A treated HLMECs. In addition, the in vivo lymphatic vessel formation stimulated by rhVEGF-A was significantly reduced by 6,8-DG. 6,8-DG inhibited the expression of VEGF-A rather than other lymphangiogenic factors in CoCl₂-treated SCCVII cells. 6,8-DG inhibited the expression and activation of VEGFR-2 stimulated by rhVEGF-A in HLMECs. Also, 6,8-DG inhibited the activation of the lymphangiogenesis-related downstream signaling factors such as FAK, PI3K, AKT, p38, and ERK in rhVEGF-A-treated HLMECs. Additionally, 6,8-DG inhibited the expression of the hypoxia-inducible factor (HIF-1α), which is involved in the expression of VEGF-A in CoCl₂-treated SCCVII cells, and 6,8-DG inhibited VEGF-A signaling via interruption of the binding of VEGF-A and VEGFR-2 in HLMECs. In the VEGF-A-induced OCSLN animal model, we confirmed that 6,8-DG suppressed tumor-induced lymphangiogenesis and SLN metastasis.

CONCLUSION

These data suggest that 6,8-DG inhibits VEGF-A-induced lymphangiogenesis and lymph node metastasis in vitro and in vivo. Furthermore, the inhibitory effects of 6,8-DG are probably mediated by inhibition of VEGF-A expression in cancer cells and suppression of the VEGF-A/VEGFR-2 signaling pathway in HLMEC. Thus, 6,8-DG could be novel and valuable therapeutic agents for metastasis prevention and treatment of oral cancer.

The anticancer activities of Vernonia amygdalina Delile. Leaves on 4T1 breast cancer cells through phosphoinositide 3-kinase (PI3K) pathway

Vernonia amygdalina Delile (Asteraceae) is used in traditional medicine to treat diabetes mellitus, and some research provides its activity to treat breast cancer. The aim of this study is to assess the anticancer activity of Vernonia amygdalina Delile leaves fractions on 4T1 breast cancer cells. Analysis of phytochemical compounds were carried out with LC-MS/MS. Cytotoxic activity was determined using the MTT method in the 4T1 cell line. Apoptosis, the cell cycle, and PI3K and mTOR profiles were analyzed with flow cytometry. The phytochemicals found were diterpene (ingenol-3-angelate) and some phenolics (chlorogenic acid and 4-methoxycinnamic acid), flavonoids (apigetrin, apigenin, luteolin, diosmetin, baicalin, rhoifolin, and scutellarin), and coumarines (7-hydroxycoumarine, 4-methylumbelliferone, and 4-methylumbelliferyl glucuronide). The results of the MTT assay showed that the IC₅₀ values n-hexane fraction, ethylacetate fraction (EAF), and ethanol fractions were 1,860.54 ± 93.11, 25.04 ± 0.36, and 1,940.84 ± 96.37 μg/mL, respectively. EAF induced early and late apoptosis, inhibited cell cycle progression on the G₂/M phase, and inhibited PI3K and mTOR expression. The EAF of Vernonia amygdalina Delile leaves showed anticancer activity on 4T1 breast cancer cells through induction of apoptosis, enhanced cell accumulation on G₂/M phases in the cell cycle, and inhibited expression of PI3K and mTOR.

Molecular mechanisms of action of epigallocatechin gallate in cancer: Recent trends and advancement

Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is an ester of epigallocatechin and gallic acid. EGCG, abundantly found in tea, is a polyphenolic flavonoid that has the potential to affect human health and disease. EGCG interacts with various recognized cellular targets and inhibits cancer cell proliferation by inducing apoptosis and cell cycle arrest. In addition, scientific evidence has illustrated the promising role of EGCG in inhibiting tumor cell metastasis and angiogenesis. It has also been found that EGCG may reverse drug resistance of cancer cells and could be a promising candidate for synergism studies. The prospective importance of EGCG in cancer treatment is owed to its natural origin, safety, and low cost which presents it as an attractive target for further development of novel cancer therapeutics. A major challenge with EGCG is its low bioavailability which is being targeted for improvement by encapsulating EGCG in nano-sized vehicles for further delivery. However, there are major limitations of the studies on EGCG, including study design, experimental bias, and inconsistent results and reproducibility among different study cohorts. Additionally, it is important to identify specific EGCG pharmacological targets in the tumor-specific signaling pathways for development of novel combined therapeutic treatments with EGCG. The present review highlights the ongoing development to identify cellular and molecular targets of EGCG in cancer. Furthermore, the role of nanotechnology-mediated EGCG combinations and delivery systems will also be discussed.

The effects of five types of tea solutions on epiboly process, neural and cardiovascular development, and locomotor capacity of zebrafish

The effects of teas on embryonic development are still known little. The objective of this study was to compare and analyze developmental effects of green tea, delicate flavor oolong tea, strong flavor oolong tea, black tea, and pu'er tea using zebrafish embryos. Embryos were exposed in tea solutions from one-cell stage; the morphology, locomotor capacity, and gene expression of embryos or larvae were analyzed. The results showed that either tea could decrease the length of body and the size of head and eyes. The effect of green tea had the most significant effects on morphology. Only green tea disturbed cell movement, epiboly, and nervous system development. All five tea solutions caused heart structure alternations and lowered heart rates, and effects caused by green tea were severe. Green tea inhibited the formation of dorsal aorta and segmental arteries and decreased the velocity and total movement distance of larvae. In conclusion, the toxicity of green tea to epiboly, neural and cardiovascular development, and locomotor capacity is more severe than that of other teas. Our study played a warning role for safety consumption of teas and provided references for further study of tea's physiological and pharmacological effects and biological activity.

Therapeutic potential of targeting the Eph/ephrin signaling complex

The Eph-ephrin signaling pathway mediates developmental processes and the proper functioning of the adult human body. This distinctive bidirectional signaling pathway includes a canonical downstream signal cascade inside the Eph-bearing cells, as well as a reverse signaling in the ephrin-bearing cells. The signaling is terminated by ADAM metalloproteinase cleavage, internalization, and degradation of the Eph/ephrin complexes. Consequently, the Eph-ephrin-ADAM signaling cascade has emerged as a key target with immense therapeutic potential particularly in the context of cancer. An interesting twist was brought forth by the emergence of ephrins as the entry receptors for the pathological Henipaviruses, which has spurred new studies to target the viral entry. The availability of high-resolution structures of the multi-modular Eph receptors in complexes with ephrins and other binding partners, such as peptides, small molecule inhibitors and antibodies, offers a wealth of information for the structure-guided development of therapeutic intervention. Furthermore, genomic data mining of Eph mutants involved in cancer provides information for targeted drug development. In this review we summarize the distinct avenues for targeting the Eph-ephrin signaling pathway, including its termination by ADAM proteinases. We highlight the latest developments in Eph-related pharmacology in the context of Eph-ephrin-ADAM-based antibodies and small molecules. Finally, the future prospects of genomics- and proteomics-based medicine are discussed.

Protective and Restorative Effects of Nutrients and Phytochemicals

Intoroduction:

Dietary intake fundamentally provides reintegration of energy and essential nutrients to human organisms. However, its qualitative and quantitative composition strongly affects individual’s health, possibly being either a preventive or a risk factor. It was shown that nutritional status resulting from long-term exposition to specific diet formulations can outstandingly reduce incidences of most common and most important diseases of the developed world, such as cardiovascular and neoplastic diseases. Diet formulations result from different food combinations which bring specific nutrient molecules. Numerous molecules, mostly but not exclusively from vegetal foods, have been characterized among nutritional components as being particularly responsible for diet capabilities to exert risk reduction. These “bioactive nutrients” are able to produce effects which go beyond basic reintegration tasks, i.e. energetic and/or structural, but are specifically pharmacologically active within pathophysiological pathways related to many diseases, being able to selectively affect processes such as cell proliferation, apoptosis, inflammation, differentiation, angiogenesis, DNA repair and carcinogens activation.

Conclusion:

The present review was aimed to know the molecular mechanisms and pathways of activity of bioactive molecules; which will firstly allow search for optimal food composition and intake, and then use them as possible therapeutical targets and/or diagnostics. Also, the present review discussed the therapeutic effect of both nutrients and phytochemicals.

Antimigration Activity of an Ethylacetate Fraction of Zanthoxylum acanthopodium DC. Fruits in 4T1 Breast Cancer Cells

Objective: This study was carried out to investigate the antimigration activity of Zanthoxylum acanthopodium DC. in the 4T1 breast cancer cell line. Methods: Zanthoxylum acanthopodium DC. fruit powder was extracted by maceration method with n-hexane and ethylacetate solvents. Cytotoxicity and proliferation were assessed using the MTT method and the cell cycle by flow cytometry. In addition, wound healing assays were conducted by a microscopic method, and expression of COX-2 and VEGFR-2 were determined using qRT-PCR. Results: The IC50 of the ethylacetate fraction (EAF) was 48.1 ± 1.06 μg/mL. The EAE at a concentration 10 μg/mL with viable cells was 62.3 ± 0.28% after 72 h incubation, with accumulation in the G2-M phase, inhibition of cell migration in the wound healing assay, and decrease in expression of COX-2 (0.62 ± 0.01) and VEGFR-2 (0.39 ± 0.003). Conclusion: The results reveal that an ethylacetate fraction of Zanthoxylum acanthopodium DC. fruits provides effective antimigration effects. Further studies are now planned to assess the potential of the ethylacetate fraction to inhibit angiogenesis in breast cancer and determine underlying mechanisms.

Inhibition of angiogenesis by leflunomide via targeting the soluble ephrin-A1/EphA2 system in bladder cancer

Angiogenesis plays an important role in bladder cancer (BCa). The immunosuppressive drug leflunomide has attracted worldwide attention. However, the effects of leflunomide on angiogenesis in cancer remain unclear. Here, we report the increased expression of soluble ephrin-A1 (sEphrin-A1) in supernatants of BCa cell lines (RT4, T24, and TCCSUP) co-cultured with human umbilical vein endothelial cells (HUVECs) compared with that in immortalized uroepithelial cells (SV-HUC-1) co-cultured with HUVECs. sEphrin-A1 is released from BCa cells as a monomeric protein that is a functional form of the ligand. The co-culture supernatants containing sEphrin-A1 caused the internalization and down-regulation of EphA2 on endothelial cells and dramatic functional activation of HUVECs. This sEphrin-A1/EphA2 system is mainly functional in regulating angiogenesis in BCa tissue. We showed that leflunomide (LEF) inhibited angiogenesis in a N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN)-induced bladder carcinogenesis model and a tumor xenograft model, as well as in BCa cell and HUVEC co-culture systems, via significant inhibition of the sEphrin-A1/EphA2 system. Ephrin-A1 overexpression could partially reverse LEF-induced suppression of angiogenesis and subsequent tumor growth inhibition. Thus, LEF has a significant anti-angiogenesis effect on BCa cells and BCa tissue via its inhibition of the functional angiogenic sEphrin-A1/EphA2 system and may have potential for treating BCa beyond immunosuppressive therapy.

Evaluation of Endometrial Angiogenesis in Mice Uterus Before Implantation in Natural Cycles Followed by Use of Human Menopausal Gonadotropin - Human Chorionic Gonadotropin Drugs and Epigallocatechin Gallate

Background:

Angiogenesis plays a major role in endometrial receptivity and thickening of the endometrium immediately before implantation. The aim of the present work was to evaluate the antiangiogenic properties of epigallocatechin-3-gallate (EGCG) from green tea in angiogenesis of endometrium.

Materials and Methods:

In this study, forty adult female NMARI mice randomly divided into four groups. Control group received vehicle; human menopausal gonadotropin/human chorionic gonadotropin (HMG/HCG) group received 7.5 IU HMG intraperitoneal (IP) and 48 h later 7.5 IU HCG was injected (IP) for ovarian stimulation; HMG/HCG + EGCG group received HMG and HCG in the same manner as the previous group and also received 5 mg/kg EGCG at 0, 24, 48, and 72 h after injection of HMG; and the group EGCG received 5 mg/kg EGCG. A male mouse was kept with two female animals in the same cage for mating. Mice were dissected 96 h after administration of HMG (immediately before implantation) and tissue processing was carried out for the uterine specimens. CD31-positive cells were counted by use of histological and immunohistochemical methods.

Results:

Angiogenesis in EGCG-treated group was less than that of control and gonadotropin group (P < 0.05). The number of endothelial cells was counted by CD31 marker under a light microscope and showed significant differences between all groups (P < 0.05).

Conclusion:

EGCG significantly inhibited the angiogenesis in endometrium (in natural cycles) through antiangiogenic effects.

Green tea (Camellia sinensis) and l-theanine: Medicinal values and beneficial applications in humans-A comprehensive review

Green tea (Camellia sinensis) is a famous herb, and its extract has been extensively used in traditional Chinese medicinal system. In this context, several studies have revealed its health benefits and medicinal potentialities for several ailments. With ever increasing scientific knowledge, search for safer, potential and novel type of health-related supplements quest, scientists are re-directing their research interests to explore natural resources i.e. medicinal herbs/plant derived compounds. Green tea consumption has gained a special attention and popularity in the modern era of changing lifestyle. The present review is aimed to extend the current knowledge by highlighting the importance and beneficial applications of green tea in humans for safeguarding various health issues. Herein, we have extensively reviewed, analyzed, and compiled salient information on green tea from the authentic published literature available in PubMed and other scientific databases. Scientific literature evidenced that owing to the bioactive constituents including caffeine, l-theanine, polyphenols/flavonoids and other potent molecules, green tea has many pharmacological and physiological functions. It possesses multi-beneficial applications in treating various disorders of humans. This review also provides in-depth insights on the medicinal values of green tea which will be useful for researchers, medical professionals, veterinarians, nutritionists, pharmacists and pharmaceutical industry. Future research emphasis and promotional avenues are needed to explore its potential therapeutic applications for designing appropriate pharmaceuticals, complementary medicines, and effective drugs as well as popularize and propagate its multidimensional health benefits.

Green tea and its anti-angiogenesis effects

The development of new blood vessels from a pre-existing vasculature (also known as angiogenesis) is required for many physiological processes including embryogenesis and post-natal growth. However, pathological angiogenesis is also a hallmark of cancer and many ischaemic and inflammatory diseases. The pro-angiogenic members of the VEGF family (vascular endothelial growth factor family), VEGF-A, VEGF-B, VEGF-C, VEGF-D and placental growth factor (PlGF), and the related receptors, VEGFR-1, VEGFR-2 and VEGFR-3 have a central and decisive role in angiogenesis. Indeed, they are the targets for anti-angiogenic drugs currently approved. Green tea (from the Camellia sinensis plant) is one of the most popular beverages in the world. It is able to inhibit angiogenesis by different mechanisms such as microRNAs (miRNAs). Green tea and its polyphenolic substances (like catechins) show chemo-preventive and chemotherapeutic features in various types of cancer and experimental models for human cancers. The tea catechins, including (-)-epigallocatechin-3-gallate (EGCG), have multiple effects on the cellular proteome and signalome. Note that the polyphenolic compounds from green tea are able to change the miRNA expression profile associated with angiogenesis in various cancer types. This review focuses on the ability of the green tea constituents to suppress angiogenesis signaling and it summarizes the mechanisms by which EGCG might inhibit the VEGF family. We also highlighted the miRNAs affected by green tea which are involved in anti-angiogenesis.

New insights into the antiangiogenic and proangiogenic properties of dietary polyphenols

Polyphenols can be found in natural products of plant origin, including vegetables, fruits, and beverages. A large number of these plant origin compounds are an integral part of the human diet and in the past decade evidence has shown their beneficial properties in human health, by acting in several cell signaling pathways. Among other beneficial effects, polyphenols have been associated with angiogenesis. Increasing evidence highlighting the ability of dietary polyphenols to influence angiogenesis by interfering with multiple signaling pathways is debated. Particular emphasis is given to the mechanisms that ultimately may induce the formation of capillary-like structures (by increasing endothelial cell proliferation, migration, and invasion) or, conversely, may inhibit the steps of angiogenesis leading to the inhibition/regress of vascular development. Dietary polyphenols can, therefore, be viewed as promising nutraceuticals but important aspects have still to be further investigated, to deep knowledge concerning their concentration-mediated effects, effect of specific polyphenols, and respective metabolites, to ensure their appropriate and effective usefulness as proangiogenic or antiangiogenic nutraceuticals.

Antioxidant and Antiproliferative Activities of an Ethylacetate Fraction of Picria Fel-Terrae Lour. Herbs

Background: Excessive production of oxygen free radicals and imbalance in the mechanisms responsible for antioxidant protection may result in the onset of many diseases including breast cancer. Objective: To evaluate antiproliferative and antioxidant activity of an ethylacetate fraction (EAF) of Picria fel-terrae Lour. Herbs in the T47D cell line. Methods: Phenolic and total flavonoid contents in EAF were determined. EAF was tested for cytotoxicity and effects on the cell cycle and apoptosis, as well as antioxidant activity. Results: EAF was found to contain high levels of phenolic agents (92.88 ± 0.50 mg GAE/g), total flavonoid (84.39 ± 0.07 mg QE/g). The EAF of Picria fel-terrae Lour. herbs was found to have an IC50 of 62.98μg/mL, caused accumulation in G0-G1 and S phase and increased early and late apoptosis. Antioxidant activity in DPPH assays gave an IC50 of 166.90 ± 0.10 μg/mL. Conclusions: The results reveal that EAF of Picria fel-terrae Lour. herbs has antiproliferative activity and strong antioxidant potential. Further studies are now needed to isolate the responsible antiproliferative and antioxidant components.

N-3 polyunsaturated fatty acids alleviate high glucose-mediated dysfunction of endothelial progenitor cells and prevent ischemic injuries both in vitro and in vivo

Hyperglycemia is associated with a reduced number of endothelial progenitor cells (EPCs) that impairs vascular function. Circulating EPCs play important roles in postnatal neovasculogenesis and the prevention of ischemic injury. Frequent consumption of fish oil (FO) that is abundant with eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) is reportedly associated with an alleviation of diabetic complications and a lowered incidence of cardiovascular disease. The aim of this study was to examine whether N-3 polyunsaturated fatty acids such as EPA and DHA would reverse the high glucose-mediated dysfunction of EPCs in vitro and thereby prevent the ischemic injury that occurs under the hyperglycemic conditions in Type 2 diabetes (T2D) db^-/- mice. The results demonstrate that EPA and DHA alleviate high glucose-mediated impairment of tubular formation in EPCs through a rescue of neovasculogenic capability. The molecular mechanisms underlying the effects of EPA and DHA include the activation of the extracellular signal-regulated kinase 1/2, Akt/endothelial nitric oxide synthase (eNOS) and AMP-activated kinase (AMPK) signaling cascades as well as the phosphorylation of the downstream FOXO3a protein in EPCs. Moreover, EPA and DHA up-regulate the expression of c-kit, erythroid 2-related factor and heme oxygenase-1 proteins. Daily consumption of FO at dosages of 4% and 6% (wt/wt) significantly increased the level of bone marrow-derived and circulating EPCs, induced a recovery of blood flow and prevented ischemic injuries in a T2D db^-/- mouse model. The effects of FO consumption were exerted the activation of Akt/eNOS and AMPK signaling cascades without any effect on the plasma VEGF level in vivo.

Concomitant inhibition of oxidative stress and angiogenesis by chronic hydrogen-rich saline and N-acetylcysteine treatments improves systemic, splanchnic and hepatic hemodynamics of cirrhotic rats

AIM

In cirrhosis, increased oxidative stress leads to systemic and splanchnic hyperdynamic circulation, splanchnic angiogenesis, portosystemic collateral formation, hepatic endothelial dysfunction, increased intrahepatic resistance and the subsequent portal hypertension. Like N-acetylcysteine, hydrogen-rich saline is a new documented antioxidant with the potential to treat the complications of liver diseases.

METHODS

In this study, hemodynamics, splanchnic angiogenesis and hepatic endothelial dysfunction were measured in common bile duct ligation (BDL)-cirrhotic rats receiving 1-month treatment of vehicle, N-acetylcysteine and hydrogen-rich saline immediately after BDL. Additionally, acute effects of N-acetylcysteine and hydrogen-rich saline on vascular endothelial growth factor (VEGF)-induced tubule formation and migration of human umbilical vein endothelial cells (HUVEC) were also evaluated.

RESULTS

The data indicate that 1-month treatment of N-acetylcysteine or hydrogen-rich saline significantly ameliorated systemic and splanchnic hyperdynamic circulation, corrected hepatic endothelial dysfunction, and decreased intrahepatic resistance and mesenteric angiogenesis by inhibiting inflammatory cytokines, nitric oxide, VEGF and reducing mesenteric oxidative stress in cirrhotic rats. In vivo studies revealed that acute co-incubation of N-acetylcysteine or hydrogen-rich saline with VEGF effectively suppressed VEGF-induced angiogenesis and migration of HUVEC accompanied by decreasing of oxidative stress and inflammatory cytokines.

CONCLUSION

Both hydrogen-rich saline and N-acetylcysteine alleviate portal hypertension, the severity of portosystemic collaterals, mesenteric angiogenesis, hepatic endothelial dysfunction and intrahepatic resistance in cirrhotic rats. N-Acetylcysteine and the new antioxidant, hydrogen-rich saline are potential treatments for the complications of cirrhosis.

Eicosapentaenoic acid induces neovasculogenesis in human endothelial progenitor cells by modulating c-kit protein and PI3-K/Akt/eNOS signaling pathways

Human endothelial progenitor cells (hEPCs) derived from bone marrow play a crucial in the prevention of ischemic injuries in the course of postnatal neovasculogenesis. Frequent fish oil (FO) consumption is reportedly associated with a significantly lower incidence of cardiovascular disease. However, the molecular mechanisms of eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) are not well elucidated, and the beneficial effect of FO consumption on neovasculogenesis has not been demonstrated yet. In the current study, we investigated the effects of EPA/DHA and FO consumption on neovasculogenesis by using vascular tube formation assay, Western blotting, real-time polymerase chain reaction, immunohistochemical staining and Doppler imaging in both in vitro and in vivo models. The results demonstrate that EPA and DHA dose-dependently enhance the neovasculogenesis and cell migration of hEPCs in vitro. The mechanisms of action included up-regulation of the c-kit protein as well as the phosphorylation of the ERK1/2, Akt and endothelial nitric oxide synthase signaling molecules in hEPCs. Furthermore, EPA significantly suppressed the expression of microRNA 221 in vitro. In experimental animal models, FO consumption significantly induced the formation of new blood vessels (neovasculogenesis) and prevented ischemia. Taken together, it is suggested that FO consumption enhances neovasculogenesis mainly through the effects of EPA in hEPCs, thereby exerting a preventive effect against ischemic injury.

In vitro inhibition of angiogenesis by hydroalcoholic extract of oak (Quercus infectoria) acorn shell via suppressing VEGF, MMP-2, and MMP-9 secretion

CONTEXT

Angiogenesis is an essential factor for cancer progression. Although more attention is paid in angiogenesis on its role in cancer biology, many other non-neoplastic diseases are also angiogenic-dependent. Recently, there is motivation to control cancer via inhibition of angiogenesis.

OBJECTIVE

Quercus infectoria Olivier var (Fagaceae) (oak) is a plant whose different parts, such as its fruit shell, have been used extensively as a traditional drug in the west part of Iran. Although some biological properties of oak are determined, its effects on angiogenesis are unclear. So, we investigated the antiangiogenic effects of oak acorn shell.

MATERIALS AND METHODS

Fresh oak acorns were collected, and after authentication; hydroalcoholic extract of acorn shells (5, 10, 20, 30, 40, 60, 80, and 100 μg/ml) was used for evaluation of its cytotoxicity, antiproliferative, and antiangiogenic effects in vitro. Also, effects of the extract on vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2) and MMP-9 secretion were assayed using enzyme-linked immunosorbent assay (ELISA) and gelatin zymography.

RESULTS

Treatment with hydroalcoholic extract in eight doses resulted in a significant decrease of endothelial cell proliferation and angiogenesis with an IC₅₀ value of ~20 μg/ml, without any toxic effect. At 40 μg/ml, the extract inhibited MMP-9 activity; however, a dose-dependent reduction (60-80 µg/ml) in MMP-2 activity was seen. VEGF secretion was decreased with increase in the concentration of the extract from 5 to 100 μg/ml.

DISCUSSION AND CONCLUSION

This study indicated that hydroalcoholic extract of oak acorn shell acts as a potent antiangiogenic agent which exerts its inhibitory effect mainly through downregulation of essential mediators such as VEGF and MMPs.

Inhibition of Eph receptor-ephrin ligand interaction by tea polyphenols

Tea contains a variety of bioactive chemicals, such as catechins and other polyphenols. These compounds are thought to be responsible for the health benefits of tea consumption by affecting the function of many cellular targets, not all of which have been identified. In a high-throughput screen for small molecule antagonists of the EphA4 receptor tyrosine kinase, we identified five tea polyphenols that substantially inhibit EphA4 binding to a synthetic peptide ligand. Further characterization of theaflavin monogallates from black tea and epigallocatechin-3,5-digallate from green tea revealed that these compounds at low micromolar concentrations also inhibit binding of the natural ephrin ligands to EphA4 and several other Eph receptors in in vitro assays. The compounds behave as competitive EphA4 antagonists, and their inhibitory activity is affected by amino acid mutations within the ephrin binding pocket of EphA4. In contrast, the major green tea catechin, epigallocatechin-3-gallate (EGCG), does not appear to be an effective Eph receptor antagonist. In cell culture assays, theaflavin monogallates and epigallocatechin-3,5-digallate inhibit ephrin-induced tyrosine phosphorylation (activation) of Eph receptors and endothelial capillary-like tube formation. However, the wider spectrum of Eph receptors affected by the tea derivatives in cells suggests additional mechanisms of inhibition besides interfering with ephrin binding. These results show that tea polyphenols derived from both black and green tea can suppress the biological activities of Eph receptors. Thus, the Eph receptor tyrosine kinase family represents an important class of targets for tea-derived phytochemicals.

Targeting Eph receptors with peptides and small molecules: progress and challenges

The Eph receptors are a large family of receptor tyrosine kinases. Their kinase activity and downstream signaling ability are stimulated by the binding of cell surface-associated ligands, the ephrins. The ensuing signals are bidirectional because the ephrins can also transduce signals (known as reverse signals) following their interaction with Eph receptors. The ephrin-binding pocket in the extracellular N-terminal domain of the Eph receptors and the ATP-binding pocket in the intracellular kinase domain represent potential binding sites for peptides and small molecules. Indeed, a number of peptides and chemical compounds that target Eph receptors and inhibit ephrin binding or kinase activity have been identified. These molecules show promise as probes to study Eph receptor/ephrin biology, as lead compounds for drug development, and as targeting agents to deliver drugs or imaging agents to tumors. Current challenges are to find (1) small molecules that inhibit Eph receptor-ephrin interactions with high binding affinity and good lead-like properties and (2) selective kinase inhibitors that preferentially target the Eph receptor family or subsets of Eph receptors. Strategies that could also be explored include targeting additional Eph receptor interfaces and the ephrin ligands.

In vitro antioxidant and anticancer activity of young Zingiber officinale against human breast carcinoma cell lines

BACKGROUND

Ginger is one of the most important spice crops and traditionally has been used as medicinal plant in Bangladesh. The present work is aimed to find out antioxidant and anticancer activities of two Bangladeshi ginger varieties (Fulbaria and Syedpuri) at young age grown under ambient (400 μmol/mol) and elevated (800 μmol/mol) CO2 concentrations against two human breast cancer cell lines (MCF-7 and MDA-MB-231).

METHODS

The effects of ginger on MCF-7 and MDA-MB-231 cell lines were determined using TBA (thiobarbituric acid) and MTT [3-(4,5-dimethylthiazolyl)-2,5-diphenyl-tetrazolium bromide] assays. Reversed-phase HPLC was used to assay flavonoids composition among Fulbaria and Syedpuri ginger varieties grown under increasing CO2 concentration from 400 to 800 μmol/mol.

RESULTS

Antioxidant activities in both varieties found increased significantly (P ≤ 0.05) with increasing CO2 concentration from 400 to 800 μmol/mol. High antioxidant activities were observed in the rhizomes of Syedpuri grown under elevated CO2 concentration. The results showed that enriched ginger extract (rhizomes) exhibited the highest anticancer activity on MCF-7 cancer cells with IC50 values of 34.8 and 25.7 μg/ml for Fulbaria and Syedpuri respectively. IC50 values for MDA-MB-231 exhibition were 32.53 and 30.20 μg/ml for rhizomes extract of Fulbaria and Syedpuri accordingly.

CONCLUSIONS

Fulbaria and Syedpuri possess antioxidant and anticancer properties especially when grown under elevated CO2 concentration. The use of ginger grown under elevated CO2 concentration may have potential in the treatment and prevention of cancer.

A disalicylic acid-furanyl derivative inhibits ephrin binding to a subset of Eph receptors

Eph receptor tyrosine kinases and ephrin ligands control many physiological and pathological processes, and molecules interfering with their interaction are useful probes to elucidate their complex biological functions. Moreover, targeting Eph receptors might enable new strategies to inhibit cancer progression and pathological angiogenesis as well as promote nerve regeneration. Because our previous work suggested the importance of the salicylic acid group in antagonistic small molecules targeting Eph receptors, we screened a series of salicylic acid derivatives to identify novel Eph receptor antagonists. This identified a disalicylic acid-furanyl derivative that inhibits ephrin-A5 binding to EphA4 with an IC(50) of 3 μm in ELISAs. This compound, which appears to bind to the ephrin-binding pocket of EphA4, also targets several other Eph receptors. Furthermore, it inhibits EphA2 and EphA4 tyrosine phosphorylation in cells stimulated with ephrin while not affecting phosphorylation of EphB2, which is not a target receptor. In endothelial cells, the disalicylic acid-furanyl derivative inhibits EphA2 phosphorylation in response to TNFα and capillary-like tube formation on Matrigel, two effects that depend on EphA2 interaction with endogenous ephrin-A1. These findings suggest that salicylic acid derivatives could be used as starting points to design new small molecule antagonists of Eph receptors.

Polyphenol rich botanicals used as food supplements interfere with EphA2-ephrinA1 system

The Eph tyrosine kinase receptors and their ephrin ligands play a central role in several human cancers and their deregulated expression or function promotes tumorigenesis, inducing aggressive tumor phenotypes. Green tea extracts (GTE) have been recently found to inhibit Eph-kinase phosphorylation. In order to evaluate the potential contribution of edible and medicinal plants on EphA2-ephrinA1 modulation, 133 commercially available plant extracts used as food supplements, essential and fixed oils were screened with an ELISA-based binding assay. Nine plant extracts, rich of polyphenols, reversibly inhibited binding in a dose-dependent manner (IC₅₀ 0.83-24 μg/ml). Functional studies on PC3 prostate adenocarcinoma cells revealed that active extracts antagonized ephrinA1-Fc-induced EphA2-phosphorylation at non-cytotoxic concentrations (IC₅₀ 0.31-11.3 μg/ml) without interfering with EGF-induced EGFR activation, suggesting a specific effect. These findings could furnish an interesting starting point regarding the potential relationship between diet, edible plant secondary metabolites and Eph-ephrin system, suggesting their possible involvement in cancer development modulation.

Nitric oxide counters the inhibitory effects of uremic toxin indoxyl sulfate on endothelial cells by governing ERK MAP kinase and myosin light chain activation

Uremic toxins such as indoxyl sulfate (IS) accumulate at a high level in end stage renal disease (ESRD) and can exhibit significant systemic endothelial toxicity leading to accelerated cardiovascular events. The precise molecular mechanisms by which IS causes endothelial dysfunction are unknown. We tested the hypothesis that IS negatively influences properties of endothelial cells, such as migration and tube formation, by depleting nitric oxide (NO) bioavailability, and that an NO donor can reverse these inhibitory effects. IS inhibited human umbilical vein endothelial cell (HUVEC) migration and formation of tubes on matrigel. Mechanistically, IS inhibited VEGF-induced NO release from HUVECs. An NO donor, SNAP, reversed IS-mediated inhibition of HUVEC migration as well as tube-formation. IS inhibited ERK 1/2 MAP kinase activity in a dose-dependent manner, but this was preserved by SNAP. Inhibition of ERK 1/2 with a pharmacological inhibitor (U0126) decreased HUVEC migration and tube formation; these effects too were prevented by SNAP. Further, IS stimulated activation of myosin light chain (MLC), potentially stimulating endothelial contractility, while SNAP decreased MLC activation. Thus, we conclude that the negative effects of IS on endothelial cells are prevented, to a major extent, by NO, via its divergent actions on ERK MAP kinase and MLC.

Resveratrol with antioxidant activity inhibits matrix metalloproteinase via modulation of SIRT1 in human fibrosarcoma cells

AIMS

Resveratrol, a silent information regulator 1 (SIRT1) activator, has been reported to act as an antioxidant contained in red wine and prevent the development of cardiovascular diseases. Histone deacetylase such as SIRT1 is involved in the regulation of lifespan extension. In this study, the effect of resveratrol on matrix metalloproteinases (MMPs) that play an important role in metastasis was examined in human fibrosarcoma cell line, HT1080.

MAIN METHODS

The effect of resveratrol on MMPs' activity was evaluated using gelatin zymography. Western blot analysis and RT-PCR assay were used to determine the effect of resveratrol on the expression level of MMP-9, MAPK and SIRT1 proteins and genes, respectively.

KEY FINDINGS

It was observed that resveratrol exhibited not only antioxidant effects on lipid peroxidation and DNA oxidation but also inhibitory effects on the expression of MMP-2 and 9 in HT1080 cells stimulated with either phorbol myristate acetate or phenazine methosulfate. Furthermore, it was found that treatment with resveratrol decreased the level of MMP-9 expression via down-regulation of p-ERK, c-fos and p65. In addition, the level of SIRT1 gene expression was also enhanced by treatment of resveratrol alone but the level of MMP-9 gene expression was decreased.

SIGNIFICANCE

These results suggest that the activation of SIRT1 in the presence of resveratrol especially inhibits the expression of MMP-9 in HT1080 cells, providing evidence that resveratrol can be a potential candidate for chemoprevention of cancer.

Regulation of survival, proliferation, invasion, angiogenesis, and metastasis of tumor cells through modulation of inflammatory pathways by nutraceuticals

Almost 25 centuries ago, Hippocrates, the father of medicine, proclaimed "Let food be thy medicine and medicine be thy food." Exploring the association between diet and health continues today. For example, we now know that as many as 35% of all cancers can be prevented by dietary changes. Carcinogenesis is a multistep process involving the transformation, survival, proliferation, invasion, angiogenesis, and metastasis of the tumor and may take up to 30 years. The pathways associated with this process have been linked to chronic inflammation, a major mediator of tumor progression. The human body consists of about 13 trillion cells, almost all of which are turned over within 100 days, indicating that 70,000 cells undergo apoptosis every minute. Thus, apoptosis/cell death is a normal physiological process, and it is rare that a lack of apoptosis kills the patient. Almost 90% of all deaths due to cancer are linked to metastasis of the tumor. How our diet can prevent cancer is the focus of this review. Specifically, we will discuss how nutraceuticals, such as allicin, apigenin, berberine, butein, caffeic acid, capsaicin, catechin gallate, celastrol, curcumin, epigallocatechin gallate, fisetin, flavopiridol, gambogic acid, genistein, plumbagin, quercetin, resveratrol, sanguinarine, silibinin, sulforaphane, taxol, gamma-tocotrienol, and zerumbone, derived from spices, legumes, fruits, nuts, and vegetables, can modulate inflammatory pathways and thus affect the survival, proliferation, invasion, angiogenesis, and metastasis of the tumor. Various cell signaling pathways that are modulated by these agents will also be discussed.

Cancer and metastasis: prevention and treatment by green tea

Metastasis is the most deadly aspect of cancer and results from several interconnected processes including cell proliferation, angiogenesis, cell adhesion, migration, and invasion into the surrounding tissue. The appearance of metastases in organs distant from the primary tumor is the most destructive feature of cancer. Metastasis remains the principal cause of the deaths of cancer patients despite decades of research aimed at restricting tumor growth. Therefore, inhibition of metastasis is one of the most important issues in cancer research. Several in vitro, in vivo, and epidemiological studies have reported that the consumption of green tea may decrease cancer risk. (-)-Epigallocatechin-3-gallate, major component of green tea, has been shown to inhibit tumor invasion and angiogenesis which are essential for tumor growth and metastasis. This article summarizes the effect of green tea and its major polyphenolic compounds on cancer and metastasis against most commonly diagnosed cancer sites.

Nanochemoprevention by bioactive food components: a perspective

Chemoprevention through the use of bioactive food components is a practical approach for cancer control. Despite abundant efficacy data under preclinical settings, this strategy has resulted in limited success for human cancer control. Amongst many reasons, inefficient systemic delivery and bioavailability of promising chemopreventive agents are considered to significantly contribute to such a disconnect. We recently introduced a novel concept in which we utilized nanotechnology for enhancing the outcome of chemoprevention (Cancer Res. 2009; 69:1712-6) and termed it nanochemoprevention. To establish the proof-of-principle of nanotechnology for cancer management, we determined the efficacy of a well-known chemopreventive agent epigallocatechin-3-gallate (EGCG) encapsulated in polylactic acid (PLA)-polyethylene glycol (PEG) nanoparticles in preclinical settings and observed that, compared to non-encapsulated EGCG, nano-EGCG retained its biological efficacy with over 10-fold dose advantage both in cell culture system and in vivo settings in athymic nude mice implanted with human prostate cancer cells. This study laid the foundation of nanochemoprevention by bioactive food components. Since oral consumption is the most desirable and acceptable form of delivery of bioactive food components, it will be important to develop nanoparticles containing bioactive food components that are suitable for oral consumption for which experiments are underway in this laboratory.

Physiological concentrations of dietary polyphenols regulate vascular endothelial cell expression of genes important in cardiovascular health

Previous cell culture-based studies have shown potential health beneficial effects on gene expression of dietary polyphenols, including those found in red wine and green tea. However, these studies have tended to use higher concentrations (2–100 μm) than those observed in blood (0·1–1 μm) after consuming polyphenol-rich foods or beverages. The present study investigated effects of physiological concentrations of different classes of dietary polyphenol on the expression of genes important in cardiovascular health (endothelial NO synthase (eNOS), endothelin-1 (ET-1) and vascular endothelial growth factor (VEGF)) by cultured vascular endothelial cells (human umbilical vein endothelial cells) in the absence or presence of H2O2. Resveratrol and quercetin (0·1–1 μm) increased eNOS and VEGF mRNA expression particularly in the absence of H2O2 (50 μm) and decreased H2O2-induced ET-1 mRNA expression (P < 0·001 for polyphenol × H2O2 interactions). Similarly, resveratrol and quercetin decreased endothelin secretion into the media, blocking the stimulatory effect of 50 μm-H2O2 (P < 0·001 for polyphenol × H2O2 interaction). Of the nine other polyphenols tested, only epigallocatechin gallate had similar effects on both the eNOS and ET-1 mRNA expression, but to a lesser extent than resveratrol at an equimolar concentration (0·1 μm). The observed effects on gene expression would be expected to result in vasodilation and thereby reduced blood pressure. Since only three of the eleven polyphenols tested had biological activity, it is unclear whether particular structures are important or whether the effects might relate to the relatively high antioxidant capacities of the three active polyphenols.

Decursin and decursinol inhibit VEGF-induced angiogenesis by blocking the activation of extracellular signal-regulated kinase and c-Jun N-terminal kinase

The root of Angelica gigas Nakai contains two major coumarins, which have been previously identified as decursin and decursinol. Decursin has been demonstrated to exhibit potent anti-cancer activity both in vitro and in vivo. In this study, we found that decursin and decursinol at non-cytotoxic doses inhibited the VEGF-induced proliferation, migration, and capillary-tube formation of HUVECs. Moreover, decursin and decursinol suppressed microvessel formation on chorioallantoic membranes in fertilized eggs and into mouse Matrigel plugs. The oral administration of decursin and decursinol also reduced VEGF-induced angiogenesis in Matrigel. Furthermore, decursin and decursinol reduced the phosphorylation of ERK and JNK, but not p38 MAPK, in VEGF-stimulated HUVECs. Taken together, our results reveal that decursin and decursinol inhibit VEGF-induced angiogenesis by reducing the activation of ERK and JNK in HUVECs, and possess potent in vivo anti-angiogenic activity, coupled with the advantage of oral dosing. Thus, these compounds may have the potential for the treatment of cancers dependent on VEGF-induced vascularization.

A subset of signal transduction pathways is required for hippocampal growth cone collapse induced by ephrin-A5

The Eph family tyrosine kinase receptors and their ligands, ephrins, play key roles in a wide variety of physiological and pathological processes including tissue patterning, angiogenesis, bone development, carcinogenesis, axon guidance, and neural plasticity. However, the signaling mechanisms underlying these diverse functions of Eph receptors have not been well understood. In this study, effects of Eph receptor activation on several important signal transduction pathways are examined. In addition, the roles of these pathways in ephrin-A5-induced growth cone collapse were assessed with a combination of biochemical analyses, pharmacological inhibition, and overexpression of dominant-negative and constitutively active mutants. These analyses showed that ephrin-A5 inhibits Erk activity but activates c-Jun N-terminal kinase. However, regulation of these two pathways is not required for ephrin-A5-induced growth cone collapse in hippocampal neurons. Artificial Erk activation by expression of constitutively active Mek1 and B-Raf failed to block ephrin-A5 effects on growth cones, and inhibitors of the Erk pathway also failed to inhibit collapse by ephrin-A5. Inhibition of JNK had no effects on ephrin-A5-induced growth cone collapse either. In addition, inhibitors to PKA and PI3-K showed no effects on ephrin-A5-induced growth cone collapse. However, pharmacological blockade of phosphotyrosine phosphatase activity, the Src family kinases, cGMP-dependent protein kinase, and myosin light chain kinase significantly inhibited ephrin-A5-induced growth cone collapse. These observations indicate that only a subset of signal transduction pathways is required for ephrin-A5-induced growth cone collapse.

Small molecules can selectively inhibit ephrin binding to the EphA4 and EphA2 receptors

The erythropoietin-producing hepatocellular (Eph) family of receptor tyrosine kinases regulates a multitude of physiological and pathological processes. Despite the numerous possible research and therapeutic applications of agents capable of modulating Eph receptor function, no small molecule inhibitors targeting the extracellular domain of these receptors have been identified. We have performed a high throughput screen to search for small molecules that inhibit ligand binding to the extracellular domain of the EphA4 receptor. This yielded a 2,5-dimethylpyrrolyl benzoic acid derivative able to inhibit the interaction of EphA4 with a peptide ligand as well as the natural ephrin ligands. Evaluation of a series of analogs identified an isomer with similar inhibitory properties and other less potent compounds. The two isomeric compounds act as competitive inhibitors, suggesting that they target the high affinity ligand-binding pocket of EphA4 and inhibit ephrin-A5 binding to EphA4 with K(i) values of 7 and 9 mum in enzyme-linked immunosorbent assays. Interestingly, despite the ability of each ephrin ligand to promiscuously bind many Eph receptors, the two compounds selectively target EphA4 and the closely related EphA2 receptor. The compounds also inhibit ephrin-induced phosphorylation of EphA4 and EphA2 in cells, without affecting cell viability or the phosphorylation of other receptor tyrosine kinases. Furthermore, the compounds inhibit EphA4-mediated growth cone collapse in retinal explants and EphA2-dependent retraction of the cell periphery in prostate cancer cells. These data demonstrate that the Eph receptor-ephrin interface can be targeted by inhibitory small molecules and suggest that the two compounds identified will be useful to discriminate the activities of EphA4 and EphA2 from those of other co-expressed Eph receptors that are activated by the same ephrin ligands. Furthermore, the newly identified inhibitors represent possible leads for the development of therapies to treat pathologies in which EphA4 and EphA2 are involved, including nerve injuries and cancer.

Resveratrol inhibits migration and invasion of human breast-cancer cells

Metastasis is the primary cause of death from breast cancer. Cell migration and invasion play important roles in neoplastic metastasis. The insulin-like growth factor (IGF-1) stimulates cell migration through activation of PI-3K/Akt signaling pathway. IGF-1 induces the tumorigenicity of many types of cancer cells and is critical for metastatic cell spread in estrogen receptor (ER)-negative breast-cancer cells. Matrix metalloproteinase-2 (MMP-2) is a key enzyme in the degradation of extracellular matrices and its expression has been dysregulated in breast cancer invasion and metastasis. Resveratrol exhibited potential anticarcinogenic activities in several studies. However, the inhibitory effects of resveratrol on the expression of MMP-2, migration and invasion of breast-cancer cell have not been demonstrated yet. In the present study, we investigated the anti-invasive mechanism of resveratrol in human breast cancer MDA-MB 435cells. Here, we showed that IGF-1 is a potent stimulant of the migration of ER-negative human breast-cancer cells. Resveratrol could inhibit IGF-1-mediated cell migration of MDA-MB 435 in vitro. The inhibitory effect of resveratrol was mediated in part through the suppression of the activation of PI-3K/Akt signaling pathway. Furthermore, IGF-1-mediated expression of MMP-2 was significantly inhibited by resveratrol in concomitance with alteration of cell invasion.

Crystal structure and NMR binding reveal that two small molecule antagonists target the high affinity ephrin-binding channel of the EphA4 receptor

The Eph receptor tyrosine kinases regulate a variety of physiological and pathological processes not only during development but also in adult organs, and therefore they represent a promising class of drug targets. The EphA4 receptor plays important roles in the inhibition of the regeneration of injured axons, synaptic plasticity, platelet aggregation, and likely in certain types of cancer. Here we report the first crystal structure of the EphA4 ligand-binding domain, which adopts the same jellyroll beta-sandwich architecture as shown previously for EphB2 and EphB4. The similarity with EphB receptors is high in the core beta-stranded regions, whereas large variations exist in the loops, particularly the D-E and J-K loops, which form the high affinity ephrin binding channel. We also used isothermal titration calorimetry, NMR spectroscopy, and computational docking to characterize the binding to EphA4 of two small molecules, 4- and 5-(2,5 dimethyl-pyrrol-1-yl)-2-hydroxybenzoic acid which antagonize ephrin-induced effects in EphA4-expressing cells. We show that the two molecules bind to the EphA4 ligand-binding domain with K(d) values of 20.4 and 26.4 microm, respectively. NMR heteronuclear single quantum coherence titrations revealed that upon binding, both molecules significantly perturb EphA4 residues Ile(31)-Met(32) in the D-E loop, Gln(43) in the E beta-strand, and Ile(131)-Gly(132) in the J-K loop. Molecular docking shows that they can occupy a cavity in the high affinity ephrin binding channel of EphA4 in a similar manner, by interacting mainly with the EphA4 residues in the E strand and D-E and J-K loops. However, many of the interactions observed in Eph receptor-ephrin complexes are absent, which is consistent with the small size of the two molecules and may account for their relatively weak binding affinity. Thus, our studies provide the first published structure of the ligand-binding domain of an EphA receptor of the A subclass. Furthermore, the results demonstrate that the high affinity ephrin binding channel of the Eph receptors is amenable to targeting with small molecule antagonists and suggest avenues for further optimization.

Epigallocatechin-3-gallate inhibits estrogen-induced activation of endometrial cells in vitro and causes regression of endometriotic lesions in vivo

BACKGROUND

Epigallocatechin-3-gallate (EGCG), the major component of green tea, is a pleiotropic substance, which may inhibit tumor growth via multiple intracellular signaling pathways. Herein, we studied whether EGCG may also be effective in the treatment of endometriosis.

METHODS

We investigated the effect of EGCG on activation by estradiol (E(2)), proliferation and vascular endothelial growth factor (VEGF) expression of isolated hamster endometrial stromal cells and glandular cells in vitro using the water-soluble tetrazolium (WST)-1 colorimetric assay and western blot analysis. In the dorsal skinfold chamber model of Syrian golden hamsters, which were treated for 14 days with EGCG or vehicle, we further analyzed angiogenesis, blood perfusion and tissue integrity of both endometriotic lesions and ovarian follicles by intravital fluorescence microscopy and histology.

RESULTS

We found that EGCG suppresses E(2)-stimulated activation, proliferation and VEGF expression of endometrial cells in vitro (all P < 0.05). Furthermore, EGCG selectively inhibited angiogenesis and blood perfusion (P < 0.05) of endometriotic lesions in vivo without affecting blood vessel development in ovarian follicles. Histology confirmed that EGCG-treatment induces regression of the endometriotic lesions.

CONCLUSIONS

Our data indicate that EGCG might be a promising therapeutic agent in the treatment of endometriosis, preventing the establishment of new endometriotic lesions.

Natural compounds with proteasome inhibitory activity for cancer prevention and treatment

The proteasome is a multicatalytic protease complex that degrades most endogenous proteins including misfolded or damaged proteins to ensure normal cellular function. The ubiquitin-proteasome degradation pathway plays an essential role in multiple cellular processes, including cell cycle progression, proliferation, apoptosis and angiogenesis. It has been shown that human cancer cells are more sensitive to proteasome inhibition than normal cells, indicating that a proteasome inhibitor could be used as a novel anticancer drug. Indeed, this idea has been supported by the encouraging results of the clinical trials using the proteasome inhibitor Bortezomib (Velcade, PS-341), a drug approved by the US Food and Drug Administration (FDA). Several natural compounds, including the microbial metabolite lactacystin, green tea polyphenols, and traditional medicinal triterpenes, have been shown to be potent proteasome inhibitors. These findings suggest the potential use of natural proteasome inhibitors as not only chemopreventive and chemotherapeutic agents, but also tumor sensitizers to conventional radiotherapy and chemotherapy. In this review, we will summarize the structures and biological activities of the proteasome and several natural compounds with proteasome inhibitory activity, and will discuss the potential use of these compounds for the prevention and treatment of human cancers.

Epigallocatechin-3-gallate (EGCG) inhibits the migratory behavior of tumor bronchial epithelial cells

Background

Many studies associated the main polyphenolic constituent of green tea, (-)-Epigallocatechin-3-gallate (EGCG), with inhibition of cancers, invasion and metastasis. To date, most of the studies have focused on the effect of EGCG on cell proliferation or death. Since cell migration is an important mechanism involved in tumor invasion, the aim of the present work was to target another approach of the therapeutic effect of EGCG, by investigating its effect on the cell migratory behavior.

Methods

The effect of EGCG (at concentrations lower than 10 μg/ml) on the migration speed of invasive cells was assessed by using 2D and 3D models of cell culture. We also studied the effects of EGCG on proteinases expression by RT-PCR analysis. By immunocytochemistry, we analyzed alterations of vimentin organization in presence of different concentrations of EGCG.

Results

We observed that EGCG had an inhibitory effect of cell migration in 2D and 3D cell culture models. EGCG also inhibited MMP-2 mRNA and protein expression and altered the intermediate filaments of vimentin.

Conclusion

Taken together, our results demonstrate that EGCG is able to inhibit the migration of bronchial tumor cells and could therefore be an attractive candidate to treat tumor invasion and cell migration.

Inhibitory effect of electrolyzed reduced water on tumor angiogenesis

Vascular endothelial growth factor (VEGF) is a key mediator of tumor angiogenesis. Tumor cells are exposed to higher oxidative stress compared to normal cells. Numerous reports have demonstrated that the intracellular redox (oxidation/reduction) state is closely associated with the pattern of VEGF expression. Electrolyzed reduced water (ERW) produced near the cathode during the electrolysis of water scavenged intracellular H(2)O(2) and decreased the release of H(2)O(2) from a human lung adenocarcinoma cell line, A549, and down-regulated both VEGF transcription and protein secretion in a time-dependent manner. To investigate the signal transduction pathway involved in regulating VEGF expression, mitogen-activated kinase (MAPK) specific inhibitors, SB203580 (p38 MAPK inhibitor), PD98059 (ERK1/2 inhibitor) and JNKi (c-Jun N-terminal protein kinase inhibitor) were applied. The results showed that only PD98059 blocks VEGF expression, suggesting an important role for ERK1/2 in regulating VEGF expression in A549 cells. As well, ERW inhibited the activation of extracellular signal-regulated kinase (ERK) in a time-dependent manner. Co-culture experiments to analyze in vitro tubule formation assay revealed that A549 cell-derived conditioned medium significantly stimulated the formation of vascular tubules in all analyzed parameters; tubule total area, tubule junction, number of tubules, and total tubule length. ERW counteracted the effect of A549 cell-conditioned medium and decreased total tube length (p<0.01). The present study demonstrated that ERW down-regulated VEGF gene transcription and protein secretion through inactivation of ERK.