Regulation Of Junctions Research Articles

Hyaluroan-regulated lymphatic permeability through S1P receptors is crucial for cancer metastasis.

Disruption of cancer lymphatic vessel barrier function occurs has been reported to involve in cancer lymphatic metastasis. Hyaluronan (HA), a major glycosaminoglycan component of the extracellular matrix, is associated with cancer metastasis. We investigated the effect of high/low molecular weight hyaluronan (HMW-HA/LMW-HA) on regulation of barrier function and tight junctions in cancer lymphatic endothelial cell (LEC) monolayer. Results showed that LMW-HA increased the permeability of cancer LEC monolayers and induced disruption of Zonula Occludens-1 (ZO-1)-mediated intercellular tight junction and actin stress fiber formation. HMW-HA treatment decreased permeability in cancer LEC monolayers and cortical actin ring formation. As reported, sphingosine 1-phosphate (S1P) receptors are involved in vascular integrity. After silencing of lymphatic vessel endothelial hyaluronan receptor (LYVE-1), upregulation of S1P receptors (S1P1 and S1P3) induced by HMW-HA/LMW-HA were inhibited, respectively. With S1P3 silenced, the disruption of ZO-1 as well as stress fiber formation and the ROCK1/RhoA signaling pathway induced by LMW-HA was not observed in cancer LEC. These results suggested that S1P receptors may play an important role in HMW-HA-/LMW-HA-mediated regulation of cancer lymphatic vessel integrity, which might be the initial step of cancer lymphatic metastasis and a useful intervention of cancer progression.

Cooperative contractility: The role of stress fibres in the regulation of cell-cell junctions

We present simulations of cell-cell adhesion as reported in a recent study [Liu et al., 2010, PNAS, 107(22), 9944-9] for two cells seeded on an array of micro-posts. The micro-post array allows for the measurement of forces exerted by the cell and these show that the cell-cell tugging stress is a constant and independent of the cell-cell junction area. In the current study, we demonstrate that a material model which includes the underlying cellular processes of stress fibre contractility and adhesion formation can capture these results. The simulations explain the experimentally observed phenomena whereby the cell-cell junction forces increase with junction size but the tractions exerted by the cell on the micro-post array are independent of the junction size. Further simulations on different types of micro-post arrays and cell phenotypes are presented as a guide to future experiments.

Gap junctional regulation of pressure, fluid force, and electrical fields in the epigenetics of cardiac morphogenesis and remodeling.

Epigenetic factors of pressure load, fluid force, and electrical fields that occur during cardiac contraction affect cardiac development, morphology, function, and pathogenesis. These factors are orchestrated by intercellular communication mediated by gap junctions, which synchronize action potentials and second messengers. Misregulation of the gap junction protein connexin (Cx) alters cardiogenesis, and can be a pathogenic factor causing cardiac conduction disturbance, fatal arrhythmia, and cardiac remodeling in disease states such as hypertension and ischemia. Changes in Cx expression can occur even when the DNA sequence of the Cx gene itself is unaltered. Posttranslational modifications might reduce arrhythmogenic substrates, improve cardiac function, and promote remodeling in a diseased heart. In this review, we discuss the epigenetic features of gap junctions that regulate cardiac morphology and remodeling. We further discuss potential clinical applications of current knowledge of the structure and function of gap junctions.

Epidermal tight junctions in health and disease

The skin, the largest organ of the body, is an essential barrier that under homeostatic conditions efficiently protects and/or minimizes damage from both environmental (e.g. microorganisms, physical trauma, ultraviolet radiation) and endogenous (e.g., cancers, inflammation) factors. This formidable barrier function resides mainly in the epidermis, a dynamic, highly-stratified epithelium. The epidermis has 2 major barrier structures: stratum corneum, the outmost layer and tight junctions, intercellular junctions that seal adjacent keratinocytes in the stratum granulosum, found below the stratum corneum.In recent years there have been significant advances in our understanding of tight junction function, composition and regulation. Herein we review what is known about tight junctions in healthy skin and keratinocyte culture systems and highlight the dynamic crosstalk observed between tight junctions and the cutaneous immune system. Finally we discuss the preliminary observations suggesting that tight junction function or protein expression may be relevant for the pathogenesis of a number of common cutaneous inflammatory and neoplastic conditions.

IBD Candidate Genes and Intestinal Barrier Regulation

Technological advances in the large scale analysis of human genetics have generated profound insights into possible genetic contributions to chronic diseases including the inflammatory bowel diseases (IBDs), Crohn's disease and ulcerative colitis. To date, 163 distinct genetic risk loci have been associated with either Crohn's disease or ulcerative colitis, with a substantial degree of genetic overlap between these 2 conditions. Although many risk variants show a reproducible correlation with disease, individual gene associations only affect a subset of patients, and the functional contribution(s) of these risk variants to the onset of IBD is largely undetermined. Although studies in twins have demonstrated that the development of IBD is not mediated solely by genetic risk, it is nevertheless important to elucidate the functional consequences of risk variants for gene function in relevant cell types known to regulate key physiological processes that are compromised in IBD. This article will discuss IBD candidate genes that are known to be, or are suspected of being, involved in regulating the intestinal epithelial barrier and several of the physiological processes presided over by this dynamic and versatile layer of cells. This will include assembly and regulation of tight junctions, cell adhesion and polarity, mucus and glycoprotein regulation, bacterial sensing, membrane transport, epithelial differentiation, and restitution.

Abstract 3218: Zyflamend, a multi-herbal product, selectively inhibits the growth of triple negative breast cancer cells in vitro

Abstract Triple negative breast cancer (TNBC), a subpopulation of breast cancer that has a high mortality rate, recently has been shown to be quite diverse with approximately 7 different molecular subtypes. As a result, treatment with an agent that can potentially target multiple pathways might be an effective approach. Zyflamend (Zy), a unique herbal preparation consisting of 10 concentrated herbal extracts, has been shown to suppress the proliferation of various cancer cells including prostate, melanoma, and bladder cancers. However, its role in TNBC has not been investigated. To examine its anticancer activity in TNBC, we utilized a crystal violet staining assay to determine the proliferation of cells, FACS analysis for cell cycle and apoptosis and gene/protein expression analysis to delineate the plausible mechanism of action. Among a number of breast cancer cell lines including MCF-7, SUM149, MDMB231, BT549 and HCC1937, Zy exerted stronger inhibitory effect in all TNBC cells with IC50 values ranging between 400-800μg/ml (0.5-1 μl/ml) whereas MCF-7, an estrogen/progesterone receptor positive cell line, required 1000μg/ml (1.5μl/ml). Similarly, the morphologies of SUM149, MDAMB231, and BT549 cell lines were notably disrupted by Zy treatment (400μg/ml) when these cells were cultured using three dimensional techniques. FACS analysis showed that there was a dramatic shift to subG1 phase, suggesting cells might undergo apoptosis. Reverse Phase Proteomic Array indicated that proteins affecting the cell cycle progression, cell junction regulation, and cell signaling were altered in BT549 and HCC1937 by 24 hr Zy treatment (800μg/ml).. When compared to the vehicle control, gene expression analysis showed that several inflammatory genes were downregulated by at least 50% and these included 5- and 12-lipooxygenase, leukotriene receptors, TNF receptor, and NF-κB in HCC1937 (800μg/ml), MDAMB231(800μg/ml) and SUM149 (400μg/ml) cells. Taken together, our preliminary data suggests that Zy inhibits TNBC proliferation by inhibiting inflammation, regulating cell cycle, and inducing cell death. Further studies are ongoing to evaluate these effects in in vivo triple negative breast cancer models. Citation Format: Angelica M. Gutierrez-Barrera, Banu K. Arun, Peiying Yang, Carrie Cartwright. Zyflamend, a multi-herbal product, selectively inhibits the growth of triple negative breast cancer cells in vitro. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3218. doi:10.1158/1538-7445.AM2014-3218

Fluorescence recovery after photobleaching reveals regulation and distribution of connexin36 gap junction coupling within mouse islets of Langerhans.

The pancreatic islets are central to the maintenance of glucose homeostasis through insulin secretion. Glucose‐stimulated insulin secretion is tightly linked to electrical activity in β cells within the islet. Gap junctions, composed of connexin36 (Cx36), form intercellular channels between β cells, synchronizing electrical activity and insulin secretion. Loss of gap junction coupling leads to altered insulin secretion dynamics and disrupted glucose homeostasis. Gap junction coupling is known to be disrupted in mouse models of pre‐diabetes. Although approaches to measure gap junction coupling have been devised, they either lack cell specificity, suitable quantification of coupling or spatial resolution, or are invasive. The purpose of this study was to develop fluorescence recovery after photobleaching (FRAP) as a technique to accurately and robustly measure gap junction coupling in the islet. The cationic dye Rhodamine 123 was used with FRAP to quantify dye diffusion between islet β cells as a measure of Cx36 gap junction coupling. Measurements in islets with reduced Cx36 verified the accuracy of this technique in distinguishing between distinct levels of gap junction coupling. Analysis of individual cells revealed that the distribution of coupling across the islet is highly heterogeneous. Analysis of several modulators of gap junction coupling revealed glucose‐ and cAMP‐dependent modulation of gap junction coupling in islets. Finally, FRAP was used to determine cell population specific coupling, where no functional gap junction coupling was observed between α cells and β cells in the islet. The results of this study show FRAP to be a robust technique which provides the cellular resolution to quantify the distribution and regulation of Cx36 gap junction coupling in specific cell populations within the islet. Future studies utilizing this technique may elucidate the role of gap junction coupling in the progression of diabetes and identify mechanisms of gap junction regulation for potential therapies.

Calcineurin and glial signaling: neuroinflammation and beyond.

Similar to peripheral immune/inflammatory cells, neuroglial cells appear to rely on calcineurin (CN) signaling pathways to regulate cytokine production and cellular activation. Several studies suggest that harmful immune/inflammatory responses may be the most impactful consequence of aberrant CN activity in glial cells. However, newly identified roles for CN in glutamate uptake, gap junction regulation, Ca2+ dyshomeostasis, and amyloid production suggest that CN’s influence in glia may extend well beyond neuroinflammation. The following review will discuss the various actions of CN in glial cells, with particular emphasis on astrocytes, and consider the implications for neurologic dysfunction arising with aging, injury, and/or neurodegenerative disease.

Intestinal barrier dysfunction develops at the onset of experimental autoimmune encephalomyelitis, and can be induced by adoptive transfer of auto-reactive T cells.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system with a pathogenesis involving a dysfunctional blood-brain barrier and myelin-specific, autoreactive T cells. Although the commensal microbiota seems to affect its pathogenesis, regulation of the interactions between luminal antigens and mucosal immune elements remains unclear. Herein, we investigated whether the intestinal mucosal barrier is also targeted in this disease. Experimental autoimmune encephalomyelitis (EAE), the prototypic animal model of MS, was induced either by active immunization or by adoptive transfer of autoreactive T cells isolated from these mice. We show increased intestinal permeability, overexpression of the tight junction protein zonulin and alterations in intestinal morphology (increased crypt depth and thickness of the submucosa and muscularis layers). These intestinal manifestations were seen at 7 days (i.e., preceding the onset of neurological symptoms) and at 14 days (i.e., at the stage of paralysis) after immunization. We also demonstrate an increased infiltration of proinflammatory Th1/Th17 cells and a reduced regulatory T cell number in the gut lamina propria, Peyer's patches and mesenteric lymph nodes. Adoptive transfer to healthy mice of encephalitogenic T cells, isolated from EAE-diseased animals, led to intestinal changes similar to those resulting from the immunization procedure. Our findings show that disruption of intestinal homeostasis is an early and immune-mediated event in EAE. We propose that this intestinal dysfunction may act to support disease progression, and thus represent a potential therapeutic target in MS. In particular, an increased understanding of the regulation of tight junctions at the blood-brain barrier and in the intestinal wall may be crucial for design of future innovative therapies.

Effects of T208E activating mutation on MARK2 protein structure and dynamics: Modeling and simulation.

Microtubule Affinity-Regulating Kinase 2 (MARK2) protein has a substantial role in regulation of vital cellular processes like induction of polarity, regulation of cell junctions, cytoskeleton structure and cell differentiation. The abnormal function of this protein has been associated with a number of pathological conditions like Alzheimer disease, autism, several carcinomas and development of virulent effects of Helicobacter pyloriββαβββ.

Biologically active substances-enriched diet regulates gonadotrope cell activation pathway in liver of adult and old rats.

According to the Hippocrates’ theorem “Let food be your medicine and medicine be your food”, dietary interventions may induce changes in the metabolic and inflammatory state by modulating the expression of important genes involved in the chronic disorders. The aim of the present study was to evaluate the influence of long-term (14 months) use of biologically active substances-enriched diet (BASE-diet) on transcriptomic profile of rats’ liver. The experiment was conducted on 36 Sprague–Dawley rats divided into two experimental groups (fed with control or BASE-diet, both n = 18). Control diet was a semi-synthetic diet formulated according to the nutritional requirements for laboratory animals. The BASE-diet was enriched with a mixture of polyphenolic compounds, β-carotene, probiotics, and n-3 and n-6 polyunsaturated fatty acids. In total, n = 3,017 differentially expressed (DE) genes were identified, including n = 218 DE genes between control and BASE groups after 3 months of feeding and n = 1,262 after 14 months. BASE-diet influenced the expression of genes involved particularly in the gonadotrope cell activation pathway and guanylate cyclase pathway, as well as in mast cell activation, gap junction regulation, melanogenesis and apoptosis. Especially genes involved in regulation of GnRH were strongly affected by BASE-diet. This effect was stronger with the age of animals and the length of diet use. It may suggest a link between the diet, reproductive system function and aging.

Increase of gap junction activities in SW480 human colorectal cancer cells.

BackgroundColorectal cancer is one of the most common cancers in the United States with an early detection rate of only 39%. Colorectal cancer cells along with other cancer cells exhibit many deficiencies in cell-to-cell communication, particularly gap junctional intercellular communication (GJIC). GJIC has been reported to diminish as cancer cells progress. Gap junctions are intercellular channels composed of connexin proteins, which mediate the direct passage of small molecules from one cell to the next. They are involved in the regulation of the cell cycle, cell differentiation, and cell signaling. Since the regulation of gap junctions is lost in colorectal cancer cells, the goal of this study is to determine the effect of GJIC restoration in colorectal cancer cells.MethodsGap Junction Activity Assay and protein analysis were performed to evaluate the effects of overexpression of connexin 43 (Cx43) and treatment of PQ1, a small molecule, on GJIC.ResultsOverexpression of Cx43 in SW480 colorectal cancer cells causes a 6-fold increase of gap junction activity compared to control. This suggests that overexpressing Cx43 can restore GJIC. Furthermore, small molecule like PQ1 directly targeting gap junction channel was used to increase GJIC. Gap junction enhancers, PQ1, at 200 nM showed a 4-fold increase of gap junction activity in SW480 cells. A shift from the P0 to the P2 isoform of Cx43 was seen after 1 hour treatment with 200 nM PQ1.ConclusionOverexpression of Cx43 and treatment of PQ1 can directly increase gap junction activity. The findings provide an important implication in which restoration of gap junction activity can be targeted for drug development.

Novel drug to treat coeliac disease

Gastrointestinal NursingVol. 12, No. 6 Journal ScanNovel drug to treat coeliac diseaseNikki WelyczkoNikki WelyczkoSearch for more papers by this authorNikki WelyczkoPublished Online:14 Jul 2014https://doi.org/10.12968/gasn.2014.12.6.8AboutSectionsView articleView Full TextPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareShare onFacebookTwitterLinked InEmail View article References Wang C, Rasmussen H, Perrow W et al. (2014) 929b Larazotide acetate, a first-in-class, novel tight junction regulator, meets primary endpoint and significantly reduces signs and symptoms of celiac disease in patients on a gluten-free diet: results of a multicenter, randomized, placebo controlled trial. Gastroenterology 146(5): S-159. doi: https://doi.org/http://dx.doi.org/10.1016/S0016-5085(14)60566-7 Crossref, Google ScholarBoon-Bee Goh G, Chow W-C, Wang R, Yuan J-M, Koh W-P (2014) Coffee, alcohol and other beverages in relation to cirrhosis mortality: the Singapore Chinese Health Study. Hepatology. doi: https://doi.org/0.1002/hep.27054 Google ScholarCuervo A, Valdés L, Salazar N et al. (2014) Pilot study of diet and microbiota: interactive associations of fibers and polyphenols with human intestinal bacteria. J Agric Food Chem 62(23): 5330-6. doi: https://doi.org/10.1021/jf501546a Crossref, Google ScholarTaitano AA, Markow M, Finan JE, Wheeler DE, Gonzalvo JP, Murr MM (2014) 233 Bariatric surgery improves histological features of nonalcoholic fatty liver disease and liver fibrosis. Gastroenterology 146(5): S-1011 Crossref, Google Scholar FiguresReferencesRelatedDetails 2 July 2014Volume 12Issue 6ISSN (print): 1479-5248ISSN (online): 2052-2835 Metrics History Published online 14 July 2014 Published in print 2 July 2014 Information© MA Healthcare LimitedPDF download

Nuclease delivery: versatile functions of SLX4/FANCP in genome maintenance.

As a scaffold, SLX4/FANCP interacts with multiple proteins involved in genome integrity. Although not having recognizable catalytic domains, SLX4 participates in diverse genome maintenance pathways by delivering nucleases where they are needed, and promoting their cooperative execution to prevent genomic instabilities. Physiological importance of SLX4 is emphasized by the identification of causative mutations of SLX4 genes in patients diagnosed with Fanconi anemia (FA), a rare recessive genetic disorder characterized by genomic instability and predisposition to cancers. Recent progress in understanding functional roles of SLX4 has greatly expanded our knowledge in the repair of DNA interstrand crosslinks (ICLs), Holliday junction (HJ) resolution, telomere homeostasis and regulation of DNA damage response induced by replication stress. Here, these diverse functions of SLX4 are reviewed in detail.

HGF and the regulation of tight junctions in human prostate cancer cells.

Hepatocyte growth factor (HGF) may impact the metastasis of prostate cancer via its action on prostate stem cells or their progeny. Tight junctions (TJs) are crucial to the process of metastasis and have been previously shown to be regulated by HGF. The present study aimed to evaluate the effect of HGF on the function of TJs in human prostate epithelial, prostate stem cell-like and prostate cancer cell lines. Four human prostate cancer cell lines (PC-3, DU-145, PZHPV-7, CaHPV-10), normal adult prostate parental epithelial cells (RWPE-1) and a stem cell-like derivative of RWPE-1 (WPE-STEM) were used to assess HGF-induced changes in TJs. A significant difference was noted in the behaviour between the WPE-STEM, RWPE-1 and the cancer cell lines which was HGF concentration-dependent. However, in the WPE-STEM cells, the effect was biphasic, with the cells seemingly resistant to HGF-modulated TJ disruption. Closer examination revealed that HGF affected the redistribution of ZO-1, ZO-2 and ZO-3 away from the TJs of confluent cells with concurrent loss of claudin-1 and claudin-5, and western blot analysis revealed a loss in TJ protein expression of ZO-1 and ZO-2. We demonstrated for the first time that HGF regulates TJ function in human prostate cells. Moreover, this regulation was dependent on the tumourigenicity of the cells, with the most aggressive cells most susceptible and the stem cell-like cells least susceptible. These data offer an intriguing glimpse of how TJs affect the behaviour of prostate cancer cells and how HGF modulates the expression and function of the molecules maintaining TJ structure and function.

Androgen-dependent sertoli cell tight junction remodeling is mediated by multiple tight junction components.

Sertoli cell tight junctions (SCTJs) of the seminiferous epithelium create a specialized microenvironment in the testis to aid differentiation of spermatocytes and spermatids from spermatogonial stem cells. SCTJs must be chronically broken and rebuilt with high fidelity to allow the transmigration of preleptotene spermatocytes from the basal to adluminal epithelial compartment. Impairment of androgen signaling in Sertoli cells perturbs SCTJ remodeling. Claudin (CLDN) 3, a tight junction component under androgen regulation, localizes to newly forming SCTJs and is absent in Sertoli cell androgen receptor knockout (SCARKO) mice. We show here that Cldn3-null mice do not phenocopy SCARKO mice: Cldn3(-/-) mice are fertile, show uninterrupted spermatogenesis, and exhibit fully functional SCTJs based on imaging and small molecule tracer analyses, suggesting that other androgen-regulated genes must contribute to the SCARKO phenotype. To further investigate the SCTJ phenotype observed in SCARKO mutants, we generated a new SCARKO model and extensively analyzed the expression of other tight junction components. In addition to Cldn3, we identified altered expression of several other SCTJ molecules, including down-regulation of Cldn13 and a noncanonical tight junction protein 2 isoform (Tjp2iso3). Chromatin immunoprecipitation was used to demonstrate direct androgen receptor binding to regions of these target genes. Furthermore, we demonstrated that CLDN13 is a constituent of SCTJs and that TJP2iso3 colocalizes with tricellulin, a constituent of tricellular junctions, underscoring the importance of androgen signaling in the regulation of both bicellular and tricellular Sertoli cell tight junctions.

Abstract 337: VE-Cadherin Mechanotransduction Regulates Lung Endothelial Contractility and Barrier Integrity

Dysfunctional regulation of endothelial adherens junctions is the direct underlying cause of vascular leak and pulmonary edema in acute lung injury. Indirect evidence suggests that cytoskeletal rearrangements are linked to adherens junction remodeling, but there is no clear demonstration that adherens junction proteins play an active role in the regulation of intracellular or extracellular mechanical tension. Here I investigate mechanotransduction (response to applied force) of VE-cadherin, the main structural protein at adherens junctions, and how this regulates global cell contractility and actin remodeling both locally and globally. Mechanical responses in human pulmonary artery endothelial cells were studied using magnetic twisting cytometry (MTC) experiments, in which shear stress was exerted on specific cell surface receptors by twisting magnetized beads bound to the cell surface. Remodeling of adherens junctions and F-actin in response to mechanical force was visualized by immunofluorescence. Confocal microscopy revealed force-actuated changes in both local and global cytoskeletal organization, as well as local rearrangements at both bead-cell and cell-cell junctions. This force-dependent remodeling correlated directly with the stiffening of VE-cadherin junctions with increasing applied stress. Treatment with cytoskeletal inhibitors significantly diminished this response. When a constant magnitude of shear stress was applied continuously over time, VE-cadherin junctions increased stiffness, suggesting active junction reinforcement. These data provide direct evidence that VE-cadherin complexes are tension sensors, and that associated mechanotransduction regulates global cell mechanics. Moreover, I present data showing that cadherin adhesions across the cell monolayer form a mechanically coupled network that regulates the endothelial barrier in response to force. This suggests a new mechanism regulating endothelial monolayer integrity.

929b Larazotide Acetate, a First In-Class, Novel Tight Junction Regulator, Meets Primary Endpoint and Significantly Reduces Signs and Symptoms of Celiac Disease in Patients on a Gluten-Free Diet: Results of a Multicenter, Randomized, Placebo Controlled Trial

Larazotide Acetate, a First In-Class, Novel Tight Junction Regulator, Meets Primary Endpoint and Significantly Reduces Signs and Symptoms of Celiac Disease in Patients on a Gluten-Free Diet: Results of a Multicenter, Randomized, Placebo Controlled Trial Chao Wang, Henrik Rasmussen, Wendy Perrow, Ciaran P. Kelly, Daniel Le7ffler, Peter Green, Richard N. Fedorak, Anthony J. DiMarino, Premysl Bercik, Joseph A. Murray, Natalie M. Bachir

Investigation of the hepatotoxicity of flutamide: Pro-survival/apoptotic and necrotic switch in primary rat hepatocytes characterized by metabolic and transcriptomic profiles in microfluidic liver biochips

We investigated the effects of the liver damage induced by flutamide in primary rat hepatocytes using liver microfluidic biochips. Flutamide is a non-steroidal anti-androgenic drug. Two flutamide concentrations, 10μM and 100μM, were used to expose the hepatocytes for 24h under perfusion. Thanks to the maintenance of hepatocyte differentiation phenotype and to the biotransformation performance in the microfluidic cultures, the metabolic ratio analysis of hydroxyflutamide, flutamide-gluthatione and hydroxyflutamide-gluthatione productions demonstrated saturation of the drug’s biotransformation process and the maintenance of a high level of flutamide at 100μM when compared to 10μM. A microarray analysis comparing flutamide (10 or 100μM) with controls revealed a common response for both concentrations illustrated by modulating the expression of the mRNA of genes associated with mitochondrial perturbation, of the proliferator-activated receptors (Ppar) signaling, lipid and fatty acid metabolism, antioxidant defense, and cell death pathways, consistently with in vitro and in vivo reports. Additionally to literature reports, our integration of the transcriptomic profiles demonstrated a specific dose dependent response. We found at 10μM a typical pro-survival/apoptosis network activation (through IGF/PDGFD upstream route and via a downstream up regulation in CREB5, BCL2, IKBKG routes in the PI3K/signaling). We also found a down regulation of mRNA levels in sugar and amino acid metabolism pathways. At 100μM a typical necrosis switch was observed associated with a down regulation of the tight junctions’ pathway, a cellular aggregation and a reduction of the cell viability. Altogether our data demonstrated the potential and the sensitivity of our liver microfluidic cultures to evaluate xenobiotic toxicity by improving in vitro analysis and reproducing both in vitro and in vivo results. Finally, we proposed two integrated synthetic networks to describe the response of rat hepatocytes to both exposure concentrations of flutamide.

Membrane-initiated estradiol signaling of epithelial-mesenchymal transition-associated mechanisms through regulation of tight junctions in human breast cancer cells.

Tumor cells utilize inappropriate epithelial-mesenchymal transition (EMT) mechanisms during the invasive process. It is becoming increasingly clear that estradiol (E2) induces breast cancer cell progression and enhances EMT; however, the mechanisms associated with this are unclear. We investigated the role of E2 on the expression and intracellular localization of the tight junction (TJ)-associated proteins, zonula occluden 1 (ZO-1), ZO-1-associated nucleic acid binding (ZONAB), and occludin, on the activation of c-Src and human epidermal growth factor receptor 2 (HER2) expression and cellular migration in the estrogen receptor (ER)-positive breast cancer cell lines, MCF-7 and T47D. We demonstrated that 1 nM E2 elicits c-Src activation after 15 min. The p-Src/ZO-1 complex led to ZO-1 and ZONAB disruption at the TJ and increased expression of HER2 mRNAs. These changes correlate with decreased expression of the epithelial markers occludin and CRB3 and increased synthesis of N-cadherin. This led to increased MCF-7 cell migration induced by E2, even in the presence of a cell proliferation inhibitor. Incubation with ICI 182,780 (Fulvestrant), an ER antagonist, precluded the effects of E2 on c-Src phosphorylation, p-Src/ZO-1 complex formation, ZO-1/ZONAB nuclear translocation, and migration of MCF-7 cells. Our findings suggest that E2 promotes TJ disruption during tumor progression and increases cell motility. We propose a novel pathway where estrogens promote EMT-associated mechanisms that possibly lead to metastasis.