Inhibitory effects of epigallocatechin-3 gallate, a polyphenol in green tea, on tumor-associated endothelial cells and endothelial progenitor cells

Effects of natural products on angiogenesis in melanoma

Melanoma is the most aggressive form of skin cancer and originates from genetic mutations in melanocytes. The disease is multifactorial, but its main cause is overexposure to UV radiation. Currently, available chemotherapy expresses little to no results, which may justify the extensive use of natural products to treat this cancer. In this study, we reviewed the inhibition of melanoma angiogenesis by natural products and its potential mechanisms using literature from PubMed, EMBASE, Web of Science, Ovid, ScienceDirect and China National Knowledge Infrastructure databases. According to summarizes 27 natural products including alkaloids, polyphenols, terpenoids, flavonoids, and steroids that effectively inhibit angiogenesis in melanoma. In addition to these there are 15 crude extracts that can be used as promising agents to inhibit angiogenesis, but their core components still deserve further investigation. There are current studies on melanoma angiogenesis involving oxidative stress, immune-inflammatory response, cell proliferation and migration and capillary formation. The above natural products can be involved in melanoma angiogenesis through core targets such as VE-cadherin, COX-2, iNOS, VEGF, bFGF, FGF2,MMP2,MMP9,IL-1β,IL-6 play a role in inhibiting melanoma angiogenesis. Effective excavation of natural products can not only clarify the mechanism of drug action and key targets, but also help to promote the preclinical research of natural products for melanoma treatment and further promote the development of new clinical drugs, which will bring the gospel to the vast number of patients who are deeply afflicted by melanoma.

Flavonoids with Anti-Angiogenesis Function in Cancer

The formation of new blood vessels, known as angiogenesis, significantly impacts the development of multiple types of cancer. Consequently, researchers have focused on targeting this process to prevent and treat numerous disorders. However, most existing anti-angiogenic treatments rely on synthetic compounds and humanized monoclonal antibodies, often expensive or toxic, restricting patient access to these therapies. Hence, the pursuit of discovering new, affordable, less toxic, and efficient anti-angiogenic compounds is imperative. Numerous studies propose that natural plant-derived products exhibit these sought-after characteristics. The objective of this review is to delve into the anti-angiogenic properties exhibited by naturally derived flavonoids from plants, along with their underlying molecular mechanisms of action. Additionally, we summarize the structure, classification, and the relationship between flavonoids with their signaling pathways in plants as anti-angiogenic agents, including main HIF-1α/VEGF/VEGFR2/PI3K/AKT, Wnt/β-catenin, JNK1/STAT3, and MAPK/AP-1 pathways. Nonetheless, further research and innovative approaches are required to enhance their bioavailability for clinical application.

The roles of epigallocatechin gallate in the tumor microenvironment, metabolic reprogramming, and immunotherapy

Cancer, a disease that modern medicine has not fully understood and conquered, with its high incidence and mortality, deprives countless patients of health and even life. According to global cancer statistics, there were an estimated 19.3 million new cancer cases and nearly 10 million cancer deaths in 2020, with the age-standardized incidence and mortality rates of 201.0 and 100.7 per 100,000, respectively. Although remarkable advancements have been made in therapeutic strategies recently, the overall prognosis of cancer patients remains not optimistic. Consequently, there are still many severe challenges to be faced and difficult problems to be solved in cancer therapy today. Epigallocatechin gallate (EGCG), a natural polyphenol extracted from tea leaves, has received much attention for its antitumor effects. Accumulating investigations have confirmed that EGCG can inhibit tumorigenesis and progression by triggering apoptosis, suppressing proliferation, invasion, and migration, altering tumor epigenetic modification, and overcoming chemotherapy resistance. Nevertheless, its regulatory roles and biomolecular mechanisms in the immune microenvironment, metabolic microenvironment, and immunotherapy remain obscure. In this article, we summarized the most recent updates about the effects of EGCG on tumor microenvironment (TME), metabolic reprogramming, and anti-cancer immunotherapy. The results demonstrated EGCG can promote the anti-cancer immune response of cytotoxic lymphocytes and dendritic cells (DCs), attenuate the immunosuppression of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs), and inhibit the tumor-promoting functions of tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), and various stromal cells including cancer-associated fibroblasts (CAFs), endothelial cells (ECs), stellate cells, and mesenchymal stem/stromal cells (MSCs). Additionally, EGCG can suppress multiple metabolic reprogramming pathways, including glucose uptake, aerobic glycolysis, glutamine metabolism, fatty acid anabolism, and nucleotide synthesis. Finally, EGCG, as an immunomodulator and immune checkpoint blockade, can enhance immunotherapeutic efficacy and may be a promising candidate for antitumor immunotherapy. In conclusion, EGCG plays versatile regulatory roles in TME and metabolic reprogramming, which provides novel insights and combined therapeutic strategies for cancer immunotherapy.

Endothelial progenitor cells as an emerging cardiovascular risk factor in the field of food and nutrition research: advances and challenges

Dietary modifications can help prevent many cardiovascular disease (CVD) events. Endothelial progenitor cells (EPCs) actively contribute to cardiovascular system maintenance and could function as surrogate markers for evaluating improvement in cardiovascular health resulting from nutritional interventions. This review summarizes the latest research progress on the impact of food and nutrients on EPCs, drawing on evidence from human, animal, and in vitro studies. Additionally, current trends and challenges faced in the field are highlighted. Findings from studies examining cells as EPCs are generally consistent, demonstrating that a healthy diet, such as the Mediterranean diet or a supervised diet for overweight people, specific foods like olive oil, fruit, vegetables, red wine, tea, chia, and nutraceuticals, and certain nutrients such as polyphenols, unsaturated fats, inorganic nitrate, and vitamins, generally promote higher EPC numbers and enhanced EPC function. Conversely, an unhealthy diet, such as one high in sugar substitutes, salt, or fructose, impairs EPC function. Research on outgrowth EPCs has revealed that various pathways are involved in the modulation effects of food and nutrients. The potential of EPCs as a biomarker for assessing the effectiveness of nutritional interventions in preventing CVDs is immense, while further clarification on definition and characterization of EPCs is required.

The oral bacterium Streptococcus mutans promotes tumor metastasis by inducing vascular inflammation

Recent studies have demonstrated a relationship between oral bacteria and systemic inflammation. Endothelial cells (ECs), which line blood vessels, control the opening and closing of the vascular barrier and contribute to hematogenous metastasis; however, the role of oral bacteria-induced vascular inflammation in tumor metastasis remains unclear. In this study, we examined the phenotypic changes in vascular ECs following Streptococcus mutans (S. mutans) stimulation in vitro and in vivo. The expression of molecules associated with vascular inflammation and barrier-associated adhesion was analyzed. Tumor metastasis was evaluated after intravenous injection of S. mutans in murine breast cancer hematogenous metastasis model. The results indicated that S. mutans invaded the ECs accompanied by inflammation and NF-κB activation. S. mutans exposure potentially disrupts endothelial integrity by decreasing VE-cadherin expression. The migration and adhesion of tumor cells were enhanced in S. mutans-stimulated ECs. Furthermore, S. mutans-induced lung vascular inflammation promoted breast cancer cell metastasis to the lungs in vivo. The results indicate that oral bacteria promote tumor metastasis through vascular inflammation and disruption of vascular barrier function. Improving oral hygiene in patients with cancer is of great significance in preventing postoperative pneumonia and tumor metastasis.

Antiangiogenic Phytochemicals Constituent of Diet as Promising Candidates for Chemoprevention of Cancer

Despite the extensive knowledge on cancer nature acquired over the last years, the high incidence of this disease evidences a need for new approaches that complement the clinical intervention of tumors. Interestingly, many types of cancer are closely related to dietary habits associated with the Western lifestyle, such as low fruit and vegetable intake. Recent advances around the old-conceived term of chemoprevention highlight the important role of phytochemicals as good candidates for the prevention or treatment of cancer. The potential to inhibit angiogenesis exhibited by many natural compounds constituent of plant foods makes them especially interesting for their use as chemopreventive agents. Here, we review the antitumoral potential, with a focus on the antiangiogenic effects, of phenolic and polyphenolic compounds, such as quercetin or myricetin; terpenoids, such as ursolic acid or kahweol; and anthraquinones from Aloe vera, in different in vitro and in vivo assays, and the available clinical data. Although clinical trials have failed to assess the preventive role of many of these compounds, encouraging preclinical data support the efficacy of phytochemicals constituent of diet in the prevention and treatment of cancer, but a deeper understanding of their mechanisms of action and better designed clinical trials are urgently needed.

Angioprevention of Urologic Cancers by Plant-Derived Foods

The number of cancer cases worldwide keeps growing unstoppably, despite the undeniable advances achieved by basic research and clinical practice. Urologic tumors, including some as prevalent as prostate, bladder or kidney tumors, are no exceptions to this rule. Moreover, the fact that many of these tumors are detected in early stages lengthens the duration of their treatment, with a significant increase in health care costs. In this scenario, prevention offers the most cost-effective long-term strategy for the global control of these diseases. Although specialized diets are not the only way to decrease the chances to develop cancer, epidemiological evidence support the role of certain plant-derived foods in the prevention of urologic cancer. In many cases, these plants are rich in antiangiogenic phytochemicals, which could be responsible for their protective or angiopreventive properties. Angiogenesis inhibition may contribute to slow down the progression of the tumor at very different stages and, for this reason, angiopreventive strategies could be implemented at different levels of chemoprevention, depending on the targeted population. In this review, epidemiological evidence supporting the role of certain plant-derived foods in urologic cancer prevention are presented, with particular emphasis on their content in bioactive phytochemicals that could be used in the angioprevention of cancer.

Inhibition of stromal biglycan promotes normalization of the tumor microenvironment and enhances chemotherapeutic efficacy

BACKGROUND

Biglycan is a proteoglycan found in the extracellular matrix. We have previously shown that biglycan is secreted from tumor endothelial cells and induces tumor angiogenesis and metastasis. However, the function of stroma biglycan in breast cancer is still unclear.

METHODS

Biglycan gene analysis and its prognostic values in human breast cancers were based on TCGA data. E0771 breast cancer cells were injected into WT and Bgn KO mice, respectively.

RESULTS

Breast cancer patients with high biglycan expression had worse distant metastasis-free survival. Furthermore, biglycan expression was higher in the tumor stromal compartment compared to the epithelial compartment. Knockout of biglycan in the stroma (Bgn KO) in E0771 tumor-bearing mice inhibited metastasis to the lung. Bgn KO also impaired tumor angiogenesis and normalized tumor vasculature by repressing tumor necrosis factor-ɑ/angiopoietin 2 signaling. Moreover, fibrosis was suppressed and CD8+ T cell infiltration was increased in tumor-bearing Bgn KO mice. Furthermore, chemotherapy drug delivery and efficacy were improved in vivo in Bgn KO mice.

CONCLUSION

Our results suggest that targeting stromal biglycan may yield a potent and superior anticancer effect in breast cancer.

Heparanase and the hallmarks of cancer

Heparanase is the only mammalian enzyme that cleaves heparan sulphate, an important component of the extracellular matrix. This leads to the remodelling of the extracellular matrix, whilst liberating growth factors and cytokines bound to heparan sulphate. This in turn promotes both physiological and pathological processes such as angiogenesis, immune cell migration, inflammation, wound healing and metastasis. Furthermore, heparanase exhibits non-enzymatic actions in cell signalling and in regulating gene expression. Cancer is underpinned by key characteristic features that promote malignant growth and disease progression, collectively termed the 'hallmarks of cancer'. Essentially, all cancers examined to date have been reported to overexpress heparanase, leading to enhanced tumour growth and metastasis with concomitant poor patient survival. With its multiple roles within the tumour microenvironment, heparanase has been demonstrated to regulate each of these hallmark features, in turn highlighting the need for heparanase-targeted therapies. However, recent discoveries which demonstrated that heparanase can also regulate vital anti-tumour mechanisms have cast doubt on this approach. This review will explore the myriad ways by which heparanase functions as a key regulator of the hallmarks of cancer and will highlight its role as a major component within the tumour microenvironment. The dual role of heparanase within the tumour microenvironment, however, emphasises the need for further investigation into defining its precise mechanism of action in different cancer settings.

Epigallocatechin-3-gallate (EGCG) Alters Histone Acetylation and Methylation and Impacts Chromatin Architecture Profile in Human Endothelial Cells

Epigallocatechin gallate (EGCG), the main green tea polyphenol, exerts a wide variety of biological actions. Epigenetically, the catechin has been classified as a DNMTs inhibitor, however, its impact on histone modifications and chromatin structure is still poorly understood. The purpose of this study was to find the impact of EGCG on the histone posttranslational modifications machinery and chromatin remodeling in human endothelial cells of both microvascular (HMEC-1) and vein (HUVECs) origin. We analyzed the methylation and acetylation status of histones (Western blotting), as well as assessed the activity (fluorometric assay kit) and gene expression (qPCR) of the enzymes playing a prominent role in shaping the human epigenome. The performed analyses showed that EGCG increases histone acetylation (H3K9/14ac, H3ac), and methylation of both active (H3K4me3) and repressive (H3K9me3) chromatin marks. We also found that the catechin acts as an HDAC inhibitor in cellular and cell-free models. Additionally, we observed that EGCG affects chromatin architecture by reducing the expression of heterochromatin binding proteins: HP1α, HP1γ. Our results indicate that EGCG promotes chromatin relaxation in human endothelial cells and presents a broad epigenetic potential affecting expression and activity of epigenome modulators including HDAC5 and 7, p300, CREBP, LSD1 or KMT2A.

Carbonic anhydrase 2 (CAII) supports tumor blood endothelial cell survival under lactic acidosis in the tumor microenvironment

Background

Tumor endothelial cells (TECs) perform tumor angiogenesis, which is essential for tumor growth and metastasis. Tumor cells produce large amounts of lactic acid from glycolysis; however, the mechanism underlying the survival of TECs to enable tumor angiogenesis under high lactic acid conditions in tumors remains poorly understood.

Methodology

The metabolomes of TECs and normal endothelial cells (NECs) were analyzed by capillary electrophoresis time-of-flight mass spectrometry. The expressions of pH regulators in TECs and NECs were determined by quantitative reverse transcription-PCR. Cell proliferation was measured by the MTS assay. Western blotting and ELISA were used to validate monocarboxylate transporter 1 and carbonic anhydrase 2 (CAII) protein expression within the cells, respectively. Human tumor xenograft models were used to access the effect of CA inhibition on tumor angiogenesis. Immunohistochemical staining was used to observe CAII expression, quantify tumor microvasculature, microvessel pericyte coverage, and hypoxia.

Results

The present study shows that, unlike NECs, TECs proliferate in lactic acidic. TECs showed an upregulated CAII expression both in vitro and in vivo. CAII knockdown decreased TEC survival under lactic acidosis and nutrient-replete conditions. Vascular endothelial growth factor A and vascular endothelial growth factor receptor signaling induced CAII expression in NECs. CAII inhibition with acetazolamide minimally reduced tumor angiogenesis in vivo. However, matured blood vessel number increased after acetazolamide treatment, similar to bevacizumab treatment. Additionally, acetazolamide-treated mice showed decreased lung metastasis.

Conclusion

These findings suggest that due to their effect on blood vessel maturity, pH regulators like CAII are promising targets of antiangiogenic therapy.

Oxidative stress or redox signalling - new insights into the effects of a proprietary multifunctional botanical dietary supplement

Recent interest has focused on maintenance of healthy levels of redox signalling and the related oxidants; these parameters are crucial for providing us with concrete nutritional targets that may help us to better understand and maintain "optimal health". Following the above hypothesis, we performed a pilot double-blind, crossover, placebo-controlled, single dose study to measure the dose-dependent effects of a proprietary plant-based dietary supplement labelled here as S7 (SPECTRA7), related to how it affected the cellular metabolic index (CMI) in healthy human participants (n = 8). We demonstrated using the electron spin resonance/electron paramagnetic resonance spectrometer NOXYSCAN that the administration S7 resulted in statistically significant, long-term, dose-dependent inhibition of mitochondrial and cellular reactive oxygen species generation by as much as 9.2 or 17.7% as well as 12.0 or 14.8% inhibition in extracellular nicotinamide-dinucleotide-phosphate oxidase system-dependent generation of O₂^•-, and 9.5 or 44.5% inhibition of extracellular H₂O₂ formation. This was reflected with dose-dependent 13.4 or 17.6% inhibition of tumour necrosis factor alpha induced cellular inflammatory resistance and also 1.7 or 2.3-times increases of bioavailable NO concentration. In this pilot study, we demonstrated the ability of a natural supplement to affect cellular redox signalling, which is considered by many researchers as oxidative stress. The design and activity of this proprietary plant-based material, in combination with the newly developed "CMI" test, demonstrates the potential of using dietary supplements to modulate redox signalling. This opens the door to future research into the use of S7 for modulation of inflammatory markers, for sports endurance or recovery applications.

Human cancer stem cells are a target for cancer prevention using (-)-epigallocatechin gallate

Purpose

Our previous experiments show that the main constituent of green-tea catechins, (−)-epigallocatechin gallate (EGCG), completely prevents tumor promotion on mouse skin initiated with 7,12-dimethylbenz(a)anthracene followed by okadaic acid and that EGCG and green tea extract prevent cancer development in a wide range of target organs in rodents. Therefore, we focused our attention on human cancer stem cells (CSCs) as targets of cancer prevention and treatment with EGCG.

Methods

The numerous reports concerning anticancer activity of EGCG against human CSCs enriched from cancer cell lines were gathered from a search of PubMed, and we hope our review of the literatures will provide a broad selection for the effects of EGCG on various human CSCs.

Results

Based on our theoretical study, we discuss the findings as follows: (1) Compared with the parental cells, human CSCs express increased levels of the stemness markers Nanog, Oct4, Sox2, CD44, CD133, as well as the EMT markers, Twist, Snail, vimentin, and also aldehyde dehydrogenase. They showed decreased levels of E-cadherin and cyclin D1. (2) EGCG inhibits the transcription and translation of genes encoding stemness markers, indicating that EGCG generally inhibits the self-renewal of CSCs. (3) EGCG inhibits the expression of the epithelial-mesenchymal transition phenotypes of human CSCs. (4) The inhibition of EGCG of the stemness of CSCs was weaker compared with parental cells. (5) The weak inhibitory activity of EGCG increased synergistically in combination with anticancer drugs.

Conclusions

Green tea prevents human cancer, and the combination of EGCG and anticancer drugs confers cancer treatment with tissue-agnostic efficacy.

Cancer chemoprevention through dietary flavonoids: what's limiting?

Flavonoids are polyphenols that are found in numerous edible plant species. Data obtained from preclinical and clinical studies suggest that specific flavonoids are chemo-preventive and cytotoxic against various cancers via a multitude of mechanisms. However, the clinical use of flavonoids is limited due to challenges associated with their effective use, including (1) the isolation and purification of flavonoids from their natural resources; (2) demonstration of the effects of flavonoids in reducing the risk of certain cancer, in tandem with the cost and time needed for epidemiological studies, and (3) numerous pharmacokinetic challenges (e.g., bioavailability, drug–drug interactions, and metabolic instability). Currently, numerous approaches are being used to surmount some of these challenges, thereby increasing the likelihood of flavonoids being used as chemo-preventive drugs in the clinic. In this review, we summarize the most important challenges and efforts that are being made to surmount these challenges.

The Green Tea Catechin Epigallocatechin Gallate Ameliorates Graft-versus-Host Disease

Allogeneic hematopoetic stem cell transplantation (allo-HSCT) is a standard treatment for leukemia and other hematologic malignancies. The major complication of allo-HSCT is graft-versus-host-disease (GVHD), a progressive inflammatory illness characterized by donor immune cells attacking the organs of the recipient. Current GVHD prevention and treatment strategies use immune suppressive drugs and/or anti-T cell reagents these can lead to increased risk of infections and tumor relapse. Recent research demonstrated that epigallocatechin gallate (EGCG), a component found in green tea leaves at a level of 25–35% at dry weight, may be useful in the inhibition of GVHD due to its immune modulatory, anti-oxidative and anti-angiogenic capacities. In murine allo-HSCT recipients treated with EGCG, we found significantly reduced GVHD scores, reduced target organ GVHD and improved survival. EGCG treated allo-HSCT recipients had significantly higher numbers of regulatory T cells in GVHD target organs and in the blood. Furthermore, EGCG treatment resulted in diminished oxidative stress indicated by significant changes of glutathione blood levels as well as glutathione peroxidase in the colon. In summary, our study provides novel evidence demonstrating that EGCG ameliorates lethal GVHD and reduces GVHD-related target organ damage. Possible mechanisms are increased regulatory T cell numbers and reduced oxidative stress.

Bone Marrow Blood Vessels: Normal and Neoplastic Niche

Blood vessels are among the most important factors in the transport of materials such as nutrients and oxygen. This study will review the role of blood vessels in normal bone marrow hematopoiesis as well as pathological conditions like leukemia and metastasis. Relevant literature was identified by a Pubmed search (1992-2016) of English-language papers using the terms bone marrow, leukemia, metastasis, and vessel. Given that blood vessels are conduits for the transfer of nutrients, they create a favorable situation for cancer cells and cause their growth and development. On the other hand, blood vessels protect leukemia cells against chemotherapy drugs. Finally, it may be concluded that the vessels are an important factor in the development of malignant diseases.

Tumour endothelial cells in high metastatic tumours promote metastasis via epigenetic dysregulation of biglycan

Tumour blood vessels are gateways for distant metastasis. Recent studies have revealed that tumour endothelial cells (TECs) demonstrate distinct phenotypes from their normal counterparts. We have demonstrated that features of TECs are different depending on tumour malignancy, suggesting that TECs communicate with surrounding tumour cells. However, the contribution of TECs to metastasis has not been elucidated. Here, we show that TECs actively promote tumour metastasis through a bidirectional interaction between tumour cells and TECs. Co-implantation of TECs isolated from highly metastatic tumours accelerated lung metastases of low metastatic tumours. Biglycan, a small leucine-rich repeat proteoglycan secreted from TECs, activated tumour cell migration via nuclear factor-κB and extracellular signal–regulated kinase 1/2. Biglycan expression was upregulated by DNA demethylation in TECs. Collectively, our results demonstrate that TECs are altered in their microenvironment and, in turn, instigate tumour cells to metastasize, which is a novel mechanism for tumour metastasis.

Heterogeneity of tumor endothelial cells and drug delivery

To date anti-angiogenic therapy has been used for cancer therapy widely, yielding promising results. However, it has been elucidated that current anti-angiogenic drug has several issues to be solved, such as side-effects and drug resistance. It has been reported that tumor endothelial cells (TECs) differ from normal counterparts. In addition, it was shown that the TECs are heterogeneous according to the malignancy status of tumor. The development of novel strategy for targeting tumor vasculature is required. Recently, we have developed an active targeting system, which targets TECs specifically. In this review, we will discuss how TECs in tumor vasculature are heterogeneous and offer new perspectives on a drug delivery system, which can target heterogeneous tumor blood vessels from a viewpoint of personalized medicine.

Natural products with therapeutic potential in melanoma metastasis

Malignant melanoma is the most aggressive form of skin cancer and accounts for about 3% of all cases of malignant tumour. Its incidence is increasing worldwide and it is becoming resistant to current therapeutic agents. Natural products continue to provide lead cytotoxic compounds for cancer treatment but less attention has been given to antimigratory compounds. This paper systematically and critically surveys all natural products with direct in vitro and in vivo pharmacological effects on migration and/or metastasis of melanoma cells and maps the mechanisms of action for these underexploited properties. As a result, over 30 natural active principles are described acting mainly through their antagonistic effects upon the TNF-α and EP2 receptors or the suppression of several protein kinases involved in metastatic pathways such as RAS, PI3K, ERK and FAK. Also, some were able to reduce the level of mesenchymal biomarkers such as N-cadherin and/or elevate the expression of other molecules such as E-cadherin. Consequently, downstream transcription factors namely NF-kB, AP-1, ATF-2, CREB, and HIF were inactivated leading to diminished production of MMPs, IL-1, IL-6, COX-2, VEGF and GM-CSF. This review also discusses the opportunity of combination therapies based on natural products and approved drugs, such as the combination of EGCG and dacarbazine, or the combination of two natural compounds such as quercetin and sulforaphane.

CXCL12-CXCR7 axis is important for tumor endothelial cell angiogenic property

We reported that tumor endothelial cells (TECs) differ from normal endothelial cells (NECs) in many aspects, such as gene expression profiles. Although CXCR7 is reportedly highly expressed in blood vessels of several tumors, its function in TECs is still unknown. To investigate this role, we isolated TECs from mouse tumor A375SM xenografts, and compared them with NECs from normal mouse dermis. After confirming CXCR7 upregulation in TECs, we analyzed its function using CXCR7 siRNA and CXCR7 inhibitor; CCX771. CXCR7 siRNA and CCX771 inhibited migration, tube formation and resistance to serum starvation in TECs but not in NECs. ERK1/2 phosphorylation was inhibited by CXCR7 knockdown in TECs. These results suggest that CXCR7 promotes angiogenesis in TECs via ERK1/2 phosphorylation. Using ELISA, we also detected CXCL12, a ligand of CXCR7, in conditioned medium from TECs, but not from NECs. CXCL12 neutralizing antibody significantly inhibited TEC random motility. VEGF stimulation upregulated CXCR7 expression in NECs, implying that VEGF mediates CXCR7 expression in endothelial cells. A CXCR7 inhibitor, CCX771 also inhibited tumor growth, lung metastasis and tumor angiogenesis in vivo. Taken together, the CXCL12-CXCR7 autocrine loop affects TEC proangiogenic properties, and could be the basis for an antiangiogenic therapy that specifically targets tumor blood vessels rather than normal vessels.

Multifunctional Envelope-Type Nano Device: Evolution from Nonselective to Active Targeting System

A paradigm shift has occurred in the field of drug delivery systems (DDS), one being intracellular targeting, and the other, active targeting. An important aspect of intracellular targeting involves delivering nucleic acids such as siRNA/pDNA rather than small molecular compounds, since the mechanism responsible for their entering a target cell is usually via endocytosis, and the efficiency of endosomal escape is a critical factor in determining the functional activities of siRNA/pDNA. A multifunctional envelope-type nano device (MEND) was developed to control the intracellular trafficking of nano carriers containing siRNA/pDNA. An octaarginine (R8) modified MEND was developed to achieve this. Considerable progress has been made in active targeting to selective tissue vasculature such as tumor, adipose tissue, and the lung where endothelial barrier is tight against nanoparticles with diameters larger than 50 nm. A dual-ligand system is proposed to enhance active targeting ability by virtue of a synergistic interaction between a selective ligand and a cell penetrating ligand. Prohibitin targeted nanoparticles (PTNP) were developed to target endothelial cells in adipose tissue, which deliver apoptotic peptides/proteins to the adipose vasculature. Lung endothelial cells can be targeted by means of the GALA peptide, which is usually used to enhance endosomal escape. These active targeting systems can induce pharmacological effects in in vivo conditions. Finally, a novel strategy for producing an original ligand has been developed, especially for the tumor vasculature. This progress in DDS promises to extend the area of nanomedicine as a breakthrough technology.

New insights on effects of a dietary supplement on oxidative and nitrosative stress in humans

The research community is generally agreed that maintenance of healthy levels of free radicals and related oxidants are important for good health. However, utilization of the "redox stress hypothesis" can provide us with concrete nutritional targets in order to better support and maintain "optimal health." Following this hypothesis we performed a crossover, double-blind, placebo-controlled, single-dose study on the effects of SPECTRA™, a dietary supplement, on oxidative stress markers (OSM) in human participants (n = 22). The measurement of OSM (ex vivo intra- and extracellular formation of reactive oxygen species (ROS, O2 (-), H2O2, OH(-)) in whole blood, respiratory activity of blood cells, as well as mitochondrial-dependent ROS formation, and respiratory activity), was performed using EPR spectrometer nOxyscan, spin probe CMH, and oxygen label NOX-15.1, respectively. Furthermore, we investigated the ability of SPECTRA™ to modulate ex vivo cellular inflammatory responses induced by stimulation with exogenous TNF-α and also followed changes in bioavailable NO concentrations. In this clinical study, we demonstrated that administration of SPECTRA™ resulted in statistically significant long-term inhibition of mitochondrial and cellular ROS generation by as much as 17% as well as 3.5-times inhibition in extracellular NADPH system-dependent generation of O2 (-), and nearly complete inhibition of extracellular H2O2 formation. This was reflected in more than two times inhibition of ex vivo cellular inflammatory response and also increases in bioavailable NO concentration. For the first time, we have measured synergetic, biological effects of a natural supplement on changes in OSM and cellular metabolic activity. The unique design and activity of the plant-based natural supplement, in combination with the newly developed and extended Vitality test, demonstrates the potential of using dietary supplements to modulate OSM and also opens the door to future research into the use of natural supplements for supporting optimal health.

Suprabasin as a novel tumor endothelial cell marker

Recent studies have reported that stromal cells contribute to tumor progression. We previously demonstrated that tumor endothelial cells (TEC) characteristics were different from those of normal endothelial cells (NEC). Furthermore, we performed gene profile analysis in TEC and NEC, revealing that suprabasin (SBSN) was upregulated in TEC compared with NEC. However, its role in TEC is still unknown. Here we showed that SBSN expression was higher in isolated human and mouse TEC than in NEC. SBSN knockdown inhibited the migration and tube formation ability of TEC. We also showed that the AKT pathway was a downstream factor of SBSN. These findings suggest that SBSN is involved in the angiogenic potential of TEC and may be a novel TEC marker.

Isolation and genome-wide expression and methylation characterization of CD31+ cells from normal and malignant human prostate tissue

Endothelial cells (ECs) are an important component involved in the angiogenesis. Little is known about the global gene expression and epigenetic regulation in tumor endothelial cells. The identification of gene expression and epigenetic difference between human prostate tumor-derived endothelial cells (TdECs) and those in normal tissues may uncover unique biological features of TdEC and facilitate the discovery of new anti-angiogenic targets. We established a method for isolation of CD31⁺ endothelial cells from malignant and normal prostate tissues obtained at prostatectomy. TdECs and normal-derived ECs (NdECs) showed >90% enrichment in primary culture and demonstrated microvascular endothelial cell characteristics such as cobblestone morphology in monolayer culture, diI-acetyl-LDL uptake and capillary-tube like formation in Matrigel^®. In vitro primary cultures of ECs maintained expression of endothelial markers such as CD31, von Willebrand factor, intercellular adhesion molecule, vascular endothelial growth factor receptor 1, and vascular endothelial growth factor receptor 2. We then conducted a pilot study of transcriptome and methylome analysis of TdECs and matched NdECs from patients with prostate cancer. We observed a wide spectrum of differences in gene expression and methylation patterns in endothelial cells, between malignant and normal prostate tissues. Array-based expression and methylation data were validated by qRT-PCR and bisulfite DNA pyrosequencing. Further analysis of transcriptome and methylome data revealed a number of differentially expressed genes with loci whose methylation change is accompanied by an inverse change in gene expression. Our study demonstrates the feasibility of isolation of ECs from histologically normal prostate and prostate cancer via CD31⁺ selection. The data, although preliminary, indicates that there exist widespread differences in methylation and transcription between TdECs and NdECs. Interestingly, only a small proportion of perturbed genes were overlapped between American (AA) and Caucasian American (CA) patients with prostate cancer. Our study indicates that identifying gene expression and/or epigenetic differences between TdECs and NdECs may provide us with new anti-angiogenic targets. Future studies will be required to further characterize the isolated ECs and determine the biological features that can be exploited in the prognosis and therapy of prostate cancer.

Identification of novel targets for antiangiogenic therapy by comparing the gene expressions of tumor and normal endothelial cells

Targeting tumor angiogenesis is an established strategy for cancer therapy. Because angiogenesis is not limited to pathological conditions such as cancer, molecular markers that can distinguish between physiological and pathological angiogenesis are required to develop more effective and safer approaches for cancer treatment. To identify such molecules, we determined the gene expression profiles of murine tumor endothelial cells (mTEC) and murine normal endothelial cells using DNA microarray analysis followed by quantitative reverse transcription–polymerase chain reaction analysis. We identified 131 genes that were differentially upregulated in mTEC. Functional analysis using siRNA-mediated gene silencing revealed five novel tumor endothelial cell markers that were involved in the proliferation or migration of mTEC. The expression of DEF6 and TMEM176B was upregulated in tumor vessels of human renal cell carcinoma specimens, suggesting that they are potential targets for antiangiogenic intervention for renal cell carcinoma. Comparative gene expression analysis revealed molecular differences between tumor endothelial cells and normal endothelial cells and identified novel tumor endothelial cell markers that may be exploited to target tumor angiogenesis for cancer treatment.

Treatment with EGCG in NSCLC leads to decreasing interstitial fluid pressure and hypoxia to improve chemotherapy efficacy through rebalance of Ang-1 and Ang-2

AIM

Microvasculature and microenvironment play important roles in proliferation, invasion, metastasis and prognosis in non-small cell lung cancer (NSCLC), which might be altered by many anti-angiogenic drugs. Epigallocatechin-3-gallate (EGCG), a natural anti-angiogenesis agent refined from green tea, was defined to have multiple effects on angiogenesis factors, such as endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) and angiopoietins (ANGs). Hypothesizing that EGCG might regulate microvasculature and microenvironment in NSCLC, the effects of EGCG on microvessel density (MVD), expression of Ang-1 and Ang-2, interstitial fluid pressure (IFP), tumor hypoxia, and chemotherapy sensitivity were examined.

METHODS AND RESULTS

EGCG treatment of A549 cells in mice bearing xenografts in vivo led to a significant decrease of MVD detected by CD31, and of Ang-2 expression detected by quantum dots double-label immunofluorescence assessment, while Ang-1 decreased with no significance. Decreased IFP was measured by the Wink-in-needle method, while hypoxia was assessed by polarographic electrode and pimonidazole (PIMO) immunohistochemistry. Assuming that these changes would increase response to chemotherapy, tumor growth studies were p[erformed in nude mice with xenografts, which were then treated with EGCG and the chemotherapeutic agent cisplatin. EGCG therapy combined with cisplatin led to synergistic inhibition of tumor growth, compared with administration of each treatment separately (P < 0.001). According to linear regression analysis, IFP was positively correlated with PIMO staining (R(2) = 0.618, P = 0.002), Ang-2 was correlated with MVD (R(2) = 0.423, P = 0.022), IFP (R(2) = 0.663, P = 0.01) and PIMO staining (R(2) = 0.694, P = 0.01).

CONCLUSION

IFP and delivery of oxygen might be improved by rebalance of Ang-1/Ang-2 under the treatment of EGCG in NSCLC, which also acts as a sensitizer of chemotherapy. These studies established a new mechanism for using EGCG as an adjuvant chemotherapy agent through modifying microvasculature and microenvironment.

Hypoxia-induced reactive oxygen species cause chromosomal abnormalities in endothelial cells in the tumor microenvironment

There is much evidence that hypoxia in the tumor microenvironment enhances tumor progression. In an earlier study, we reported abnormal phenotypes of tumor-associated endothelial cells such as those resistant to chemotherapy and chromosomal instability. Here we investigated the role of hypoxia in the acquisition of chromosomal abnormalities in endothelial cells. Tumor-associated endothelial cells isolated from human tumor xenografts showed chromosomal abnormalities, >30% of which were aneuploidy. Aneuploidy of the tumor-associated endothelial cells was also shown by simultaneous in-situ hybridization for chromosome 17 and by immunohistochemistry with anti-CD31 antibody for endothelial staining. The aneuploid cells were surrounded by a pimonidazole-positive area, indicating hypoxia. Human microvascular endothelial cells expressed hypoxia-inducible factor 1 and vascular endothelial growth factor A in response to either hypoxia or hypoxia-reoxygenation, and in these conditions, they acquired aneuploidy in 7 days. Induction of aneuploidy was inhibited by either inhibition of vascular endothelial growth factor signaling with vascular endothelial growth factor receptor 2 inhibitor or by inhibition of reactive oxygen species by N-acetyl-L-cysteine. These results indicate that hypoxia induces chromosomal abnormalities in endothelial cells through the induction of reactive oxygen species and excess signaling of vascular endothelial growth factor in the tumor microenvironment.

Effect of EGCG Application on Collagen Degradation in Dentine Caries

Caries progress might be controlled when collagen matrix could be preserved after demineralization. The aim of this study was to investigate the effect of EGCG, a major polyphenol of green tea, on changes in loss of dry weight or solubilization of collagen from demineralized dentin sections. Dentin sections (1mm×5mm×5mm) were completely exposed to the acetic acid solution to form dentine caries. After baseline measurements of dry mass, the samples were divided into 2 groups and incubated at 37°C in either media containing EGCG or artificial saliva only for 24h, 3 days, 1 week, 2 week and 3 weeks. Following hydrolyzed with HCl, hydroxyproline (HOP) as an index of solubilization of collagen was analysed quantitatively. Both the storage medium and the storage time showed significant effects on mass loss and HOP release (p < 0.05). The incubation in EGCG resulted in relatively rapid and significant (p < 0.05) decrease in the amounts of mass loss. The HOP content of the experimental media also increased with incubation time but was significantly lower (p < 0.05) than in the control artificial saliva medium. It can be concluded that EGCG can inhibit collagen degradation and affects the further demineralization in dentin matrix, which consequently inhibits the advanced dentine caries.

RNAi-mediated gene knockdown and anti-angiogenic therapy of RCCs using a cyclic RGD-modified liposomal-siRNA system

Angiogenesis is one of crucial processes associated with tumor growth and development, and consequently a prime target for cancer therapy. Although tumor endothelial cells (TECs) play a key role in pathological angiogenesis, investigating phenotypical changes in neovessels when a gene expression in TEC is suppressed is a difficult task. Small interfering RNA (siRNA) represents a potential agent due to its ability to silence a gene of interest. We previously developed a system for in vivo siRNA delivery to cancer cells that involves a liposomal-delivery system, a MEND that contains a unique pH-sensitive cationic lipid, YSK05 (YSK-MEND). In the present study, we report on the development of a system that permits the delivery of siRNA to TECs by combining the YSK-MEND and a ligand that is specific to TECs. Cyclo(Arg-Gly-Asp-D-Phe-Lys) (cRGD) is a well-known ligand to αVβ3 integrin, which is selectively expressed at high levels in TECs. We incorporated cRGD into the YSK-MEND (RGD-MEND) to achieve an efficient gene silencing in TECs. Quantitative RT-PCR and the 5' rapid amplification of cDNA ends PCR indicated that the intravenous injection of RGD-MEND at a dose of 4.0mg/kg induced a significant RNAi-mediated gene reduction in TEC but not in endothelial cells of other organs. Finally, we evaluated the therapeutic potency of the RGD-MEND encapsulating siRNA against vascular endothelial growth factor receptor 2. A substantial delay in tumor growth was observed after three sequential RGD-MEND injections on alternate days. In conclusion, the RGD-MEND represents a new approach for the characterization of TECs and for us in anti-angiogenic therapy.

Lysyl oxidase secreted by tumour endothelial cells promotes angiogenesis and metastasis

Background:

Molecules that are highly expressed in tumour endothelial cells (TECs) may be candidates for specifically targeting TECs. Using DNA microarray analysis, we found that the lysyl oxidase (LOX) gene was upregulated in TECs compared with its expression in normal endothelial cells (NECs). LOX is an enzyme that enhances invasion and metastasis of tumour cells. However, there are no reports on the function of LOX in isolated TECs.

Methods:

TECs and NECs were isolated to investigate LOX function in TECs. LOX inhibition of in vivo tumour growth was also assessed using β-aminopropionitrile (BAPN).

Results:

LOX expression was higher in TECs than in NECs. LOX knockdown inhibited cell migration and tube formation by TECs, which was associated with decreased phosphorylation of focal adhesion kinase (Tyr 397). Immunostaining showed high LOX expression in human tumour vessels in vivo. Tumour angiogenesis and micrometastasis were inhibited by BAPN in an in vivo tumour model.

Conclusion:

LOX may be a TEC marker and a possible therapeutic target for novel antiangiogenic therapy.

Heterogeneity of tumor endothelial cells

Tumor blood vessels play important roles in tumor progression and metastasis. Thus, targeting tumor blood vessels is an important strategy for cancer therapy. Tumor endothelial cells (TECs) are the main targets of anti-angiogenic therapy. Although tumor blood vessels generally sprout from pre-existing vessels and have been thought to be genetically normal, they display a markedly abnormal phenotype, including morphological changes. The degree of angiogenesis is determined by the balance between the positive and negative regulating molecules that are released by tumor and host cells in the microenvironment. Reportedly, tumor blood vessels are heterogeneous with TECs differing from normal endothelial cells (in contrast to the conventional view). We recently compared characteristics of different TECs isolated from highly and low metastatic tumors. We found TECs from highly metastatic tumors had more proangiogenic phenotypes than those from low metastatic tumors. Elucidating the variety of TEC phenotypes and identifying TEC molecular signatures should lead to more complete understanding of the mechanisms of tumor progression, discovery of new therapeutic targets, and development of biomarkers. This review considers current studies on TEC heterogeneity and discusses the therapeutic implications of these findings.

An approach to transgene expression in liver endothelial cells using a liposome-based gene vector coated with hyaluronic acid

Dysfunctional sinusoidal liver endothelial cells (LECs) are associated with liver diseases, such as liver fibrosis, cirrhosis, and portal hypertension. Because of this, gene therapy targeted to LECs would be a useful and productive strategy for directly treating these diseases at the level of genes. Here, we report on the development of a transgene vector that specifically targets LECs. The vector is a liposome-based gene vector coated with hyaluronic acid (HA). HA is a natural ligand for LECs and confers desirable properties on particles, rendering them biodegradable, biocompatible, and nonimmunogenic. In this study, we constructed HA-modified carriers, and evaluated cellular uptake and transfection activity using cultured LECs from KSN nude mice (KSN-LECs). Cellular uptake analyses showed that KSN-LECs recognized the HA-modified carriers more effectively than skin endothelial cells. The transfection assay indicated that the efficient gene expression in KSN-LECs, using the HA-modified carriers, required an adequate lipid composition and a functional device to control intracellular trafficking. This finding contributes to our overall knowledge of transgene expression targeted to LECs.

Emerging phytochemicals for prevention of melanoma invasion

Cutaneous malignant melanoma is the leading cause of death from skin diseases due to its propensity to metastasize. Once diagnosed with metastatic melanoma, most patients will die of their disease within 2years. As suppression of metastases requires long-term interventions, potential anti-metastatic agents must not only be efficacious but also have low toxicity. Many phytochemicals used in traditional medicine have low toxicity and recent studies suggest that some are promising candidates for the prevention or treatment of metastatic melanoma. Here, we review the recent literature regarding phytochemicals that have shown inhibitory effects on melanoma cell migration or invasion.

Tumour endothelial cells acquire drug resistance in a tumour microenvironment

Tumour growth is dependent on angiogenesis, and tumour blood vessels are recognized as an important target for cancer therapy. Tumour endothelial cells (TECs) are the main targets of anti-angiogenic therapy. Unlike the traditionally held view, some TECs may be genetically abnormal and might acquire drug resistance. Therefore, we investigated the drug resistance of TECs and the mechanism by which it is acquired. TECs show resistance to paclitaxel through greater mRNA expression of multidrug resistance 1, which encodes P-glycoprotein, as compared with normal endothelial cells. We found that high levels of vascular endothelial growth factor in tumour-conditioned medium may be responsible for upregulated P-glycoprotein expression. This is a novel mechanism for the acquisition of drug resistance by TECs in a tumour microenvironment. This review focuses on the possibility that TECs can acquire drug resistance.

Berry fruits modulated endothelial cell migration and angiogenesis via phosphoinositide-3 kinase/protein kinase B pathway in vitro in endothelial cells

Polyphenolic-rich berry fruits are known to activate redox-sensitive cellular signaling molecules such as phosphatidylinositol-3-kinase (PI3 kinase)/kinase B (Akt), resulting in a cascade of downstream signaling pathways. This study investigated the ability of strawberry (SB), wild blueberry (WBB), and cranberry (CB) extracts to induce the activation of PI3 kinase/Akt signaling in vitro in human umbilical endothelial cells (HUVECs) and whether this activation would enhance cell migration and angiogenesis. Anthocyanin profiles of the extracts were characterized using HPLC-ESI/MS, and Akt activation was investigated using the Alpha Screen SureFire assay. The total anthocyanin contents of SB, WBB, and CB extracts were 81.7, 82.5, and 83.0 mg/100 g fresh weight, respectively. SB, WBB, and CB extracts activated Akt in a dose-dependent manner via PI3 kinase and induced cell migration and angiogenesis in vitro in HUVECs. The results from this study suggest that polyphenolics in berry fruits may play a role in promoting vascular health.

Prostacyclin receptor in tumor endothelial cells promotes angiogenesis in an autocrine manner

Molecules highly expressed in tumor endothelial cells (TEC) are important for specific targeting of these cells. Previously, using DNA microarray analysis, we found that the prostacyclin receptor (IP receptor) gene was upregulated in TEC compared with normal endothelial cells (NEC). Although prostacyclin is implicated in re-endothelialization and angiogenesis, its role remains largely unknown in TEC. Moreover, the effect of the IP receptor on TEC has not been reported. In the present study we investigated the function of the IP receptor in TEC. The TEC were isolated from two types of human tumor xenografts in nude mice, while NEC were isolated from normal counterparts. Prostacyclin secretion levels in TEC were significantly higher than those in NEC, as shown using ELISA. Real-time RT-PCR showed that the IP receptor was upregulated in TEC compared with NEC. Furthermore, migration and tube formation of TEC were suppressed by the IP receptor antagonist RO1138452. Immunohistostaining showed that the IP receptor was specifically expressed in blood vessels of renal cell carcinoma specimens, but not in glomerular vessels of normal renal tissue. These findings suggest that the IP receptor is a TEC-specific marker and might be a useful therapeutic target.

Tumor-derived microvesicles induce proangiogenic phenotype in endothelial cells via endocytosis

Background

Increasing evidence indicates that tumor endothelial cells (TEC) differ from normal endothelial cells (NEC). Our previous reports also showed that TEC were different from NEC. For example, TEC have chromosomal abnormality and proangiogenic properties such as high motility and proliferative activity. However, the mechanism by which TEC acquire a specific character remains unclear. To investigate this mechanism, we focused on tumor-derived microvesicles (TMV). Recent studies have shown that TMV contain numerous types of bioactive molecules and affect normal stromal cells in the tumor microenvironment. However, most of the functional mechanisms of TMV remain unclear.

Methodology/Principal Findings

Here we showed that TMV isolated from tumor cells were taken up by NEC through endocytosis. In addition, we found that TMV promoted random motility and tube formation through the activation of the phosphoinositide 3-kinase/Akt pathway in NEC. Moreover, the effects induced by TMV were inhibited by the endocytosis inhibitor dynasore. Our results indicate that TMV could confer proangiogenic properties to NEC partly via endocytosis.

Conclusion

We for the first time showed that endocytosis of TMV contributes to tumor angiogenesis. These findings offer new insights into cancer therapies and the crosstalk between tumor and endothelial cells mediated by TMV in the tumor microenvironment.

Biglycan is a specific marker and an autocrine angiogenic factor of tumour endothelial cells

BACKGROUND

We isolated tumour endothelial cells (TECs), demonstrated their abnormalities, compared gene expression profiles of TECs and normal endothelial cells (NECs) by microarray analysis and identified several genes upregulated in TECs. We focused on the gene encoding biglycan, a small leucine-rich repeat proteoglycan. No report is available on biglycan expression or function in TECs.

METHODS

The NEC and TEC were isolated. We investigated the biglycan expression and function in TECs. Western blotting analysis of biglycan was performed on sera from cancer patients.

RESULTS

Biglycan expression levels were higher in TECs than in NECs. Biglycan knockdown inhibited cell migration and caused morphological changes in TECs. Furthermore, immunostaining revealed strong biglycan expression in vivo in human tumour vessels, as in mouse TECs. Biglycan was detected in the sera of cancer patients but was hardly detected in those of healthy volunteers.

CONCLUSION

These findings suggested that biglycan is a novel TEC marker and a target for anti-angiogenic therapy.