EAhy926 Cell Line Research Articles

Biological assessment of new tetrahydroacridine derivatives with fluorobenzoic moiety in vitro on A549 and HT-29 cell lines and in vivo on animal model

A new series of tetrahydroacridine derivatives with the fluorobenzoyl moiety was synthesized and evaluated for cytotoxic activity against lung cancer cell lines A549 and colorectal cancer HT29. The cytotoxic activity of the compounds was compared on the somatic cell line—EAhy926. Compounds showed high cytotoxic activity on A549 cells (IC50 183.26–68.07 μM) and HT29 cells (IC50 68.41–19.70 μM), higher than controls—etoposide (IC50 451.47 μM) toward A549 and 5-fluorouracil (IC50 1626.85 μM) against HT29. Derivative 4 was the most cytotoxic to A549, whereas for the cell lines HT29 compound 6. Selected compounds showed similar cytotoxicity to the EAhy926 cell line (IC50 about 50 μM). In the hyaluronidase inhibition assay, all compounds exhibited anti-inflammatory activity, including 4 exhibiting the best inhibitory activity—IC50 of 52.27 μM when the IC50 heparin was 56.41 μM. Mathematical modeling was performed to determine LD50 after intraperitoneal, oral, intravenous and subcutaneous administration and to predict potential mutagenicity and carcinogenicity of the compounds analyzed. Obtained results showed that tested derivatives are slightly toxic compounds, and LD50 values (mg/kg) ranged from 680 to 1200 (oral rat model), the analyzed compounds have low mutagenic potential, and differences between derivatives are insignificant and very low probability of carcinogenicity. To confirm mathematical calculations, an in vivo test was carried out on a laboratory mouse model for two selected compounds. It allowed to qualify compounds: 6 to category 4 of the GHS scale, and 4 to category 3 of the GHS scale.

Nimbolide upregulates RECK by targeting miR-21 and HIF-1\u03b1 in cell lines and in a hamster oral carcinogenesis model

Reversion-inducing cysteine-rich protein with Kazal motifs (RECK), a potent inhibitor of matrix metalloproteinases (MMPs) is a common negative target of oncogenic signals and a potential therapeutic target for novel drug development. Here, we show that sequential RECKlessness stimulates angiogenesis and Notch signalling in the 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis model, a paradigm for oral oncogenesis and chemointervention. We also report the chemotherapeutic effect of nimbolide, a limonoid from the neem tree (Azadirachta indica) based on the upregulation of RECK as well as modulation of the expression of key molecules involved in invasion and angiogenesis. We demonstrate that nimbolide upregulates RECK by targeting miR-21, and HIF-1α resulting in reduced MMP activity and blockade of VEGF and Notch signalling. Nimbolide reduced microvascular density, confirming its anti-angiogenic potential. Molecular docking analysis revealed interaction of nimbolide with HIF-1α. Additionally, we demonstrate that nimbolide upregulates RECK expression via downregulation of HIF-1α and miR-21 by overexpression and knockdown experiments in SCC4 and EAhy926 cell lines. Taken together, these findings provide compelling evidence that targeting RECK, a keystone protein that regulates mediators of invasion and angiogenesis with phytochemicals such as nimbolide may be a robust therapeutic approach to prevent oral cancer progression.

Antibody Engineering of Anti-TFPI Bypass Therapeutic BAY 1093884: Isotype Selection and Sequence Optimization

Background: BAY 1093884 is a fully human monoclonal antibody against tissue factor pathway inhibitor (TFPI) developed as a bypass agent for patients with hemophilia with or without inhibitors. It restores insufficient thrombin burst, leading to stable clot formation in hemophilic conditions in vitro, and effectively stops bleeding in vivo.Aims: Antibody targeting of TFPI provides the advantages of monoclonal antibodies, such as longer circulation half-life, and the possibility of subcutaneous administration. However, antibody therapeutics can present the challenge of delivering unwanted effects or activities, such as antibody-dependent cell cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) that target healthy tissues in the patient. Additionally, antibody sequence engineering that optimizes binding to the target protein may introduce immunogenic epitopes that can induce antidrug antibodies and compromise efficacy.Methods: In vitro assays used primary human umbilical vein endothelial cells and EA-hy926 cell lines as target cells. Total peripheral blood mononuclear cells (PBMCs) and purified natural killer (NK) cells isolated from healthy donors were used as effector cells for ADCC. Pooled human serum complement (Quidel®) was used for CDC assays. A proprietary immunogenicity scoring program for T-cell epitopes (Bayer HealthCare) was used to determine immunogenic potential of BAY 1093884 relative to antibodies in the market.Results: In vitro ADCC assessment of BAY 1093884 using PBMCs and NK cells isolated from healthy donors showed no lytic activity against TFPI-expressing primary and immortalized cell lines. Furthermore, no CDC activity using pooled serum complement was detected with BAY 1093884. In silico scoring for T-cell epitopes using a human leukocyte antigen DR-weighted algorithm compared favorably to therapeutic antibodies that have been reported to have low immunogenicity in the clinic.Conclusion: In vitro and in silico immunoprofiling has aided in the design of the bypass anti-TFPI immunoglobulin G2 antibody BAY 1093884 with low toxicity potential and immunogenicity in humans. DisclosuresPaz:Bayer HealthCare: Employment. Xie:Bayer HealthCare: Employment. Aswad:Bayer HealthCare: Employment.

Abstract 5289: In human endothelial cell line Wnt-beta-catenin pathway controls transcription of lymphoid enhancer-binding factor 1, a representative of vertebrate-specific Lef1/Tcf1 sub-family enhancing matrix metalloproteinase-2 transcription and endothelial cell invasion

Abstract Background: Wnt signaling is activated in many types of cancer and normal physiological processes. Various Wnt-related secreted factors may influence angiogenesis both in the tumor microenvironment and in normal tissues by direct action on endothelial cells. The mechanism of this Wnt action in angiogenesis is not well defined. Gradl D, König A, and Wedlich D (2002) show that members of Tcf1/Lef1 sub-family generate stronger Wnt throughput and Xenopus’ secondary axis induction per protein unit than members of Tcf3/Tcf4 sub-family. This stronger activity might require different, may be, stronger chemotherapy tools for angiogenesis control than the tools necessary to prevent colon cancer where Tcf4 signaling is prominent. We hypothesize that endothelial cells are responsive to Wnt signals and that Lef1, a member of the vertebrate-specific Wnt/beta-catenin throughput-inducing transcription factors’ sub-family Lef1/Tcf1, mediates this responsiveness and promotes endothelial cell invasion. Methods: A human endothelial cell line, EAhy926 was exposed to Wnt3a or directly transfected with Lef1. Readouts included assessment of nuclear β-catenin, Wnt throughput with a SuperTOPflash reporter assay, induction of Lef1 transcription, induction of matrix metalloproteinase (MMP)-2 transcription, cell proliferation and cell invasion through a matrix in vitro. The effects on MMP2 were also evaluated in the presence of Lef1 silencing siRNA. Results: Wnt3a increased nuclear β-catenin staining identified by DNA staining of nucleus with DAPI and up-regulated Wnt/β-catenin throughput without changing the activity of negative control reporter with mutated Lef/Tcf binding sites (FOP). Wnt3a increased Lef1 transcription and activity of the Lef1 promoter. Both Wnt3a treatment and Lef1 overexpression induced MMP2 transcription but this effect was completely abrogated in the presence of Lef1 siRNA. Inhibition of Lef1 also reduced basal MMP2 levels suggesting that Lef1 regulates MMP2 expression even in the absence of exogenous Wnt pathway activation. Lef1 slightly enhanced proliferation of EAhy926 cells after prolonged periods (96 and 120 hours post-transfection) and increased invasion by more than two-fold. Conclusions: EAhy926 cell line activates canonical Wnt signaling in response to Wnt3a ligand. A representative of vertebrate-specific Lef1/Tcf1 sub-family Lef1 specifically regulates MMP2 transcription in these cells and promotes endothelial cell invasion. This cell line provides a convenient alternative to primary human umbilical vein endothelial cells (HUVEC) in the study of angiogenesis and the role of Wnt signaling on endothelial cell function. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5289. doi:1538-7445.AM2012-5289

Protective effect of hydroxysafflor yellow A on endothelial cell injury induced by lipopolysaccharide

To observe the protective effect of hydroxyl safflor yellow A (HSYA) on endothelial cell (EC). It has been observed by RT-PCR that HSYA can inhibit the elevation of TNF-alpha, IL-6, ICAM-1 and VCAM-1 mRNA level induced by LPS. The result of immunofluorescence test suggested that HSYA can alleviate p65 subgroup of NF-kappaB nuclear translocation. The experiment on EA-HY926 cell line proved that HSYA can protect EC against inflammation injury.

Beclin1/PI3K-Mediated Autophagy Prevents Hypoxia-Induced Apoptosis in EAhy926 Cell Line

Although hypoxia can induce cell death, the cancer cells and endothelial cells within a solid tumor that remain active in the hypoxia microenvironment often possess an enhanced survival potential. Developing approaches aimed at increasing the sensitivity of endothelial cells to hypoxia-induced cell death represents a potentially important avenue for antiangiogenesis treatment. This study investigated approaches to increase the sensitivity of endothelial cells to hypoxia-induced apoptosis. Autophagy and apoptosis of endothelial cells induced by hypoxia were investigated by transmission electron microscopy, confocallaser microscopy, and western blotting. Moreover, cell invasion was observed by a transwell assay and F-actin quantitative analysis. In this study, it was found that hypoxia could induce both autophagy and apoptosis in hypoxia-inducible factor-1- and Beclin1-dependent endothelial cells. Hypoxia-induced autophagy was prohibited by phosphatidylinositol 3-kinase/Akt inhibitor but not mitogen-activated protein kinase inhibitor. Inhibition of autophagy promoted the rate of apoptosis. Further, the reversal of hypoxia-induced autophagy increased cell migration compared with the normoxia condition. This study concludes that hypoxia triggers a feedback mechanism that delays apoptosis of endothelial cells and that is driven by hypoxia-induced autophagy. Thus, approaches aimed at the disruption of this mechanism can be expected to enhance the susceptibility of endothelial cells to hypoxia-induced apoptosis.

Lymphoid enhancer-binding factor 1, a representative of vertebrate-specific Lef1/Tcf1 sub-family, is a Wnt-beta-catenin pathway target gene in human endothelial cells which regulates matrix metalloproteinase-2 expression and promotes endothelial cell invasion

BackgroundWnt signaling is activated in many types of cancer and normal physiological processes. Various Wnt-related secreted factors may influence angiogenesis both in the tumor microenvironment and in normal tissues by direct action on endothelial cells. The mechanism of this Wnt action in angiogenesis is not well defined. We hypothesize that endothelial cells are responsive to Wnt signals and that Lef1, a member of the vertebrate-specific Wnt/beta-catenin throughput-inducing transcription factors' sub-family Lef1/Tcf1, mediates this responsiveness and promotes endothelial cell invasion.MethodsA human endothelial cell line, EAhy926 was exposed to Wnt3a or directly transfected with Lef1. Readouts included assessment of nuclear beta-catenin, Wnt throughput with a SuperTOPflash reporter assay, induction of Lef1 transcription, induction of matrix metalloproteinase (MMP)-2 transcription, cell proliferation and cell invasion through a matrix in vitro. The effects on MMP2 were also evaluated in the presence of Lef1 silencing siRNA.ResultsWnt3a increased nuclear beta-catenin and up-regulated Wnt/beta-catenin throughput. Wnt3a increased Lef1 transcription and activity of the Lef1 promoter. Both Wnt3a treatment and Lef1 overexpression induced MMP2 transcription but this effect was completely abrogated in the presence of Lef1 siRNA. Inhibition of Lef1 also reduced basal MMP2 levels suggesting that Lef1 regulates MMP2 expression even in the absence of exogenous Wnt pathway activation. Lef1 slightly increased proliferation of EAhy926 cells and increased invasion by more than two-fold.ConclusionsEAhy926 cells activate canonical Wnt signaling in response to Wnt3a ligand. The Wnt target Lef1 specifically regulates MMP2 expression in these cells and promotes endothelial cell invasion. The EAhy926 cell line provides a convenient alternative to primary human umbilical vein endothelial cells (HUVEC) in the study of angiogenesis and the role of Wnt signaling on endothelial cell function.

Abstract LB-367: Wnt-dependent transcription factor LEF-1 controls endothelial cell invasion through changes of MMP-2 expression

Abstract Background: Wnt signaling is involved in many events including embryogenesis, stem cell regulation, morphogenesis, cell fate determination, and oncogenesis. The role of Wnt pathway in angiogenesis is proposed, however the mechanism is still unclear. Most cancers express elevated levels of different Wnts when compared to normal cells. LEF-1 is a participant in and a target gene of the Wnt/ -catenin pathway. LEF-1 increases the in vitro invasiveness of cancer cells. Hypothesis: We suggest that LEF-1 controls the invasion also in endothelial cells. We hypothesize further that cancer affects local tumor angiogenesis via Wnt pathway-dependent up-regulation of LEF-1 in endothelial cells (EC). Methods: To test this hypothesis we construct a model system: endothelial cell line EaHy926 treated with Wnt3a (mostly known as a canonical Wnt signal) conditioned medium or grown in co-culture with L-cells producing Wnt3a. Results: Wnt3a increases nuclear ß-catenin in human endothelial cell line, and up-regulates LEF/TCF-dependent promoter activity. Wnt3a augments its target gene's LEF-1 promoter activity and LEF-1 mRNA concentration, demonstrating involvement of some transcription factors with E-tails. Both Wnt3a treatment and LEF-1 overexpression elevate MMP-2 mRNA level. Elimination of Wnt-dependent induction of MMP-2 gene expression by LEF-1 siRNA confirms the LEF-1 role in the MMP-2 control mechanism. Loosening up the extracellular matrix MMPs allows the cells to move around. These enzymes are integral part of invasion process. Indeed, LEF-1 up-regulates endothelial cells invasiveness in Matrigel matrix. LEF-1 increases also EC proliferation, in agreement with published data for parental primary endothelial culture HUVEC. Conclusions: In endothelial cells canonical (ß-catenin) Wnt signaling enhances invasiveness of EC via LEF-1 - dependent regulation of MMP-2 expression. There is a number of similarities between primary cells HUVEC, studied by others, and cell line EAhy926 in their response to Wnt3a. This indicates that EAhy926 cell line conserves many components of angiogenesis control by Wnt/β-catenin pathway and could serve as a simplified model to study this regulation, replacing primary endothelial cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-367.

Simulated microgravity perturbs actin polymerization to promote nitric oxide-associated migration in human immortalized Eahy926 cells

Microgravity causes endothelium dysfunctions and vascular endothelium remodeling in astronauts returning from space flight. Cardiovascular deconditioning occurs as a consequence of an adaptive response to microgravity partially due to the effects exerted at cellular level. Directional migration of endothelial cell which are central in maintaining the structural integrity of vascular walls is regulated by chemotactic, haptotactic, and mechanotactic stimuli which are essential for vasculogenesis. We explored the migration property of transformed endothelial cells (EC) exposed to 2-h microgravity, simulated using a three-dimensional clinostat constructed based on blueprint published by the Fokker Space, Netherlands. Migration of EC was measured using the scrap wound healing in the presence or absence of actin polymerization inhibitor-cytochalasin D (CD) in Eahy926 cell lines. Simulated microgravity increased cellular migration by 25% while CD-blocked microgravity induced cellular migration. The key migratory structures of cells, filopodia and lamellipodia, formed by EC were more in simulated microgravity compared to gravity. Parallel experiments with phalloidin and diaminorhodamine-4M (DAR-4M) showed that simulated microgravity caused actin rearrangements that lead to 25% increase in nitric oxide production. Further nitric oxide measurements showed a higher nitric oxide production which was not abrogated by phosphoinositol 3 kinase inhibitor (Wortmanin). Bradykinin, an inducer of nitric oxide, prompted two folds higher nitric oxide production along with simulated microgravity in a synergistic manner. We suggest that limited exposure to simulated microgravity increases Eahy926 cell migration by modulating actin and releasing nitric oxide.

Size‐Dependent Cytotoxicity of Monodisperse Silica Nanoparticles in Human Endothelial Cells

The effect that monodisperse amorphous spherical silica particles of different sizes have on the viability of endothelial cells (EAHY926 cell line) is investigated. The results indicate that exposure to silica nanoparticles causes cytotoxic damage (as indicated by lactate dehydrogenase (LDH) release) and a decrease in cell survival (as determined by the tetrazolium reduction, MTT, assay) in the EAHY926 cell line in a dose-related manner. Concentrations leading to a 50% reduction in cell viability (TC(50)) for the smallest particles tested (14-, 15-, and 16-nm diameter) ranging from 33 to 47 microg cm(-2) of cell culture differ significantly from values assessed for the bigger nanoparticles: 89 and 254 microg cm(-2) (diameter of 19 and 60 nm, respectively). Two fine silica particles with diameters of 104 and 335 nm show very low cytotoxic response compared to nanometer-sized particles with TC(50) values of 1095 and 1087 microg cm(-2), respectively. The smaller particles also appear to affect the exposed cells faster with cell death (by necrosis) being observed within just a few hours. The surface area of the tested particles is an important parameter in determining the toxicity of monodisperse amorphous silica nanoparticles.

Oxidized-LDL Induce the Expression of Heat Shock Protein 70 in Human Endothelial Cells

Heat shock proteins are detectable in human atherosclerotic plaques, especially in endothelial cells. In this report we show by immunofluorescence that incubation "in vitro" with OxLDL is a stress capable of inducing the expression of heat shock protein 70 in both the EAhy-926 cell line and human umbilical vein endothelial cells (HUVEC). This induction was parallel to the cytotoxicity of oxidized LDL as determined by [3H] adenine release. When cells were confluent, however, both effects were greatly reduced. We speculate that induction of hsp70 is related to the citotoxicity of oxidized LDL and that the detection of heat shock proteins in human atherosclerotic plaques is a further indication for the presence "in vivo" of oxidized LDL. These observations may be relevant to the understanding of endothelial response to injury in proatherosclerotic events.

Targeting of Cytotoxic Conjugates to Kaposi's Sarcoma-Derived Cells

AbstractWe assayed the cytotoxicity of conjugates in which the plant toxin saporin (SAP) was linked to human basic fibroblast growth factor (bFGF) and urokinase-type plasminogen activator (uPA). Both bFGF and uPA play an important role in angiogenesis, and their cell surface receptors are expressed at high levels in cancer cells. The conjugates were tested on a Kaposi's sarcoma-derived cell line, IST-KS2, as a model of an actively proliferating component of Kaposi's sarcoma lesions which are highly vascularized. Both bFGF and uPA were very effective at targeting saporin to KS cells, leading to cell killing even at low concentrations of the conjugates. The bFGF–SAP and uPA–SAP mitotoxins were also highly toxic toward the permanent, endothelium-derived EAhy926 cell line. EAhy926 cells were very sensitive to two immunotoxins containing an anti-endothelium monoclonal antibody coupled to saporin or ricin A chain, whereas IST-KS2 cells were not affected by these conjugates, in agreement with immuno cytochemical...

In vitro model of angiogenesis using a human endothelium-derived permanent cell line: contributions of induced gene expression, G-proteins, and integrins.

The EA hy926 cell line is a continuous, clonable, human cell line that displays a number of features characteristic of vascular endothelial cells (Edgell et al., 1983). Here we report that when EA hy926 cells (EA cells) are plated on an extracellular matrix material [Matrigel], they undergo a process of morphological re-organization leading to the formation of a complex network of cord or tubelike structures. These events seem to resemble, in some respects, an in vitro process of angiogenesis. The morphological re-arrangement occurs within a 12-16 hr period and seems to require expression of new messenger RNA and protein, since it is completely blocked when actinomycin D or cycloheximide are present at the time the cells are plated on Matrigel. This is not due to overt toxicity of the drugs, since exposure of cells to actinomycin D at 2 hr or more after plating on Matrigel has little effect on the formation of the tubelike structures. The process of Matrigel-induced tube formation also apparently involves a G-protein mediated signal. Treatment of the EA cells with pertussis toxin completely blocks the process and causes the ADP-ribosylation of a 42 kD protein that is recognized by an antibody to Gi-alpha subunits. In contrast, concentrations of pertussis toxin sufficient to block tube formation have only modest effects on the adhesion or motility of EA cells on purified matrix components such as laminin or collagen IV. The process of Matrigel-induced tube formation also involves integrins since monoclonal antibodies to integrin alpha 6 or beta 1 subunits can completely block the process. The concentrations of anti-integrin antibodies needed to block tube formation are much lower than those required to block cell adhesion on purified matrix components and are sufficient to occupy less than 10% of the alpha 6 or beta 1 subunits available at the cell surface. These results suggest that integrins may be involved in this potential model of angiogenesis in processes beyond their usual role in cell adhesion. Based on these results, it seems likely that the EA hy 926 cell line will prove to be a useful model for in vitro study of angiogenic processes.