World Antibody Drug Conjugate Summit Europe: February 21–23, 2011; Frankfurt,Germany

The World Antibody Drug Conjugate Summit Europe, organized by Biorbis/Hanson Wade was held in Frankfurt, Germany February 21–23, 2011. Antibody drug conjugates (ADCs), also called immunoconjugates, are becoming an increasingly important class of therapeutics as demonstrated by the attendance of nearly 100 delegates at this highly focused meeting. Updates on three ADCs that are in late-stage clinical development, trastuzumab emtansine (T-DM1), brentuximab vedotin (SGN-35) and inotuzumab ozogamicin (CMC-544), were presented by speakers from ImmunoGen, Genentech, Roche, Seattle Genetics and Pfizer. These ADCs have shown encouraging therapeutic effects against solid tumors (T-DM1) and hematological malignancies (SGN-35, CMC-544). The key feature of the new generation of ADCs is the effective combination of the cytotoxicity of natural or synthetic highly potent antineoplastic agents, tumor selective monoclonal antibodies and blood-stable optimized linkers. Early clinical data for ADCs were showcased by Progenics Pharmaceuticals (PSMA ADC), Celldex (CDX-011) and Biotest (BT-062). Takeda, MedImmune and sanofi-aventis outlined their strategies for process development and analytical characterization. In addition, presentations on duocarmycin based-ADCs, α emitting immunoconjugates and antibody-conjugated nanoparticles were given by representatives from Syntarga, Algeta and the University of Stuttgart, respectively.Key words: antibody drug conjugates, immunoconjugates, trastuzumab emtansine, brentuximab vedotin, inotuzumab ozogamicin, oncology, cancer     

Impaired Antibody Response Causes Persistence of Prototypic T Cell–Contained Virus

CD8 T cells are recognized key players in control of persistent virus infections, but increasing evidence suggests that assistance from other immune mediators is also needed. Here, we investigated whether specific antibody responses contribute to control of lymphocytic choriomeningitis virus (LCMV), a prototypic mouse model of systemic persistent infection. Mice expressing transgenic B cell receptors of LCMV-unrelated specificity, and mice unable to produce soluble immunoglobulin M (IgM) exhibited protracted viremia or failed to resolve LCMV. Virus control depended on immunoglobulin class switch, but neither on complement cascades nor on Fc receptor γ chain or Fc γ receptor IIB. Cessation of viremia concurred with the emergence of viral envelope-specific antibodies, rather than with neutralizing serum activity, and even early nonneutralizing IgM impeded viral persistence. This important role for virus-specific antibodies may be similarly underappreciated in other primarily T cell–controlled infections such as HIV and hepatitis C virus, and we suggest this contribution of antibodies be given consideration in future strategies for vaccination and immunotherapy.     

Shoot Na+ Exclusion and Increased Salinity Tolerance Engineered by Cell Type–Specific Alteration of Na+ Transport in Arabidopsis

Soil salinity affects large areas of cultivated land, causing significant reductions in crop yield globally. The Na⁺ toxicity of many crop plants is correlated with overaccumulation of Na⁺ in the shoot. We have previously suggested that the engineering of Na⁺ exclusion from the shoot could be achieved through an alteration of plasma membrane Na⁺ transport processes in the root, if these alterations were cell type specific. Here, it is shown that expression of the Na⁺ transporter HKT1;1 in the mature root stele of Arabidopsis thaliana decreases Na⁺ accumulation in the shoot by 37 to 64%. The expression of HKT1;1 specifically in the mature root stele is achieved using an enhancer trap expression system for specific and strong overexpression. The effect in the shoot is caused by the increased influx, mediated by HKT1;1, of Na⁺ into stelar root cells, which is demonstrated in planta and leads to a reduction of root-to-shoot transfer of Na⁺. Plants with reduced shoot Na⁺ also have increased salinity tolerance. By contrast, plants constitutively expressing HKT1;1 driven by the cauliflower mosaic virus 35S promoter accumulated high shoot Na⁺ and grew poorly. Our results demonstrate that the modification of a specific Na⁺ transport process in specific cell types can reduce shoot Na⁺ accumulation, an important component of salinity tolerance of many higher plants.     

Extraction of Pharmacokinetic Evidence of Drug–Drug Interactions from the Literature

Drug-drug interaction (DDI) is a major cause of morbidity and mortality and a subject of intense scientific interest. Biomedical literature mining can aid DDI research by extracting evidence for large numbers of potential interactions from published literature and clinical databases. Though DDI is investigated in domains ranging in scale from intracellular biochemistry to human populations, literature mining has not been used to extract specific types of experimental evidence, which are reported differently for distinct experimental goals. We focus on pharmacokinetic evidence for DDI, essential for identifying causal mechanisms of putative interactions and as input for further pharmacological and pharmacoepidemiology investigations. We used manually curated corpora of PubMed abstracts and annotated sentences to evaluate the efficacy of literature mining on two tasks: first, identifying PubMed abstracts containing pharmacokinetic evidence of DDIs; second, extracting sentences containing such evidence from abstracts. We implemented a text mining pipeline and evaluated it using several linear classifiers and a variety of feature transforms. The most important textual features in the abstract and sentence classification tasks were analyzed. We also investigated the performance benefits of using features derived from PubMed metadata fields, various publicly available named entity recognizers, and pharmacokinetic dictionaries. Several classifiers performed very well in distinguishing relevant and irrelevant abstracts (reaching F1≈0.93, MCC≈0.74, iAUC≈0.99) and sentences (F1≈0.76, MCC≈0.65, iAUC≈0.83). We found that word bigram features were important for achieving optimal classifier performance and that features derived from Medical Subject Headings (MeSH) terms significantly improved abstract classification. We also found that some drug-related named entity recognition tools and dictionaries led to slight but significant improvements, especially in classification of evidence sentences. Based on our thorough analysis of classifiers and feature transforms and the high classification performance achieved, we demonstrate that literature mining can aid DDI discovery by supporting automatic extraction of specific types of experimental evidence.     

The “Multi” of Drug Resistance Explained by Oscillating Drug Transporters,Drug–Membrane Physical Interactions and Spatial Dimensionality

Multi-drug resistance (MDR) can be explained by a drug handling-type activity. In this context it is also necessary to consider the multi-specificity between drugs and drug transporters in order to explain MDR. Accordingly, the efficiency of drug efflux in MDR has always been a conceptual problem in biochemistry. Indeed, how one protein can expel, from cells, hundreds of compounds with high specificity is still controversial today. To safeguard the notion of biochemical specificity, many studies have suggested alternative mechanisms to Pgp-mediated drug resistance, which do not involve the handling of drugs. However, none of these studies have definitively ruled out the possibility concept of drug handling. Thus, until now it was not possible to imagine MDR without drug-transporter affinity or specificity. However, drug-transporter affinity is not always needed to generate what appears to be a very efficient chemical reaction. Indeed, based on the fact that bi-dimensional diffusion properties (i.e. diffusion in the membrane) are paramount to explain drug pumping-mediated MDR, it is possible to suggest how specific mathematical properties of random motions can be used to construct a model of Pgp-MDR, providing that Pgp oscillates between open/drug-accepting and closed/drug-expelling conformations. This different viewpoint highlights the fact that the multi-specificity of drug transporters and the “vacuum cleaner” hypothesis may actually be two sides of the same coin, both explained by the diffusion properties of drugs in the membrane. After retrieving basic results, predictions will be highlighted. Finally, the coherence of this model in the context of cancer biology will be discussed further.     

Degradation of Cell Wall of Mucor mucedo by Chitosanase from Bacillus R–4

To broaden our understanding of extracellular proteins of Aspergillus oryzae at the conidial germination stage, analyses of the secreted proteins during germination were carried out. Taka-amylase A (TAA), glucoamylase (GLAA), and aspergillopepsin A (PEPA) were identified as the main products by peptide mass fingerprinting. TAA and PEPA were detected simultaneously with the formation of germ tubes. With the development of germination, the pH of the medium fell from 5.5 to 3.5. The secreted PEPA had a pro-sequence and likely shifted from 42 kDa to 41 kDa below pH 4.6, indicating that the precursor of PEPA was secreted and underwent pH-dependent processing. Furthermore, the 41 kDa protein was trapped by the addition of pepstatin A, the specific inhibitor of PEPA, suggesting that the maturation of pro-PEPA was a stepwise autoprocessing upon acidification of the medium and itself was an intermediate of the processing. It was implied that PEPA plays an important role at the early germination stage.     

Engineered Cystine Knot Miniproteins as Potent Inhibitors of Human Mast Cell Tryptase β

Here we report the design, chemical and recombinant synthesis, and functional properties of a series of novel inhibitors of human mast cell tryptase β, a protease of considerable interest as a therapeutic target for the treatment of allergic asthma and inflammatory disorders. These inhibitors are derived from a linear variant of the cyclic cystine knot miniprotein MCoTI-II, originally isolated from the seeds of Momordica cochinchinensis. A synthetic cyclic miniprotein that bears additional positive charge in the loop connecting the N- and C-termini inhibits all monomers of the tryptase β tetramer with an overall equilibrium dissociation constant K_i of 1 nM and thus is one of the most potent proteinaceous inhibitors of tryptase β described to date. These cystine knot miniproteins may therefore become valuable scaffolds for the design of a new generation of tryptase inhibitors.     

Rearrangements of the Actin Cytoskeleton and E-Cadherin–Based Adherens Junctions Caused by Neoplasic Transformation Change Cell–Cell Interactions

E-cadherin–mediated cell–cell adhesion, which is essential for the maintenance of the architecture and integrity of epithelial tissues, is often lost during carcinoma progression. To better understand the nature of alterations of cell–cell interactions at the early stages of neoplastic evolution of epithelial cells, we examined the line of nontransformed IAR-2 epithelial cells and their descendants, lines of IAR-6-1 epithelial cells transformed with dimethylnitrosamine and IAR1170 cells transformed with N-RasG12D. IAR-6-1 and IAR1170 cells retained E-cadherin, displayed discoid or polygonal morphology, and formed monolayers similar to IAR-2 monolayer. Fluorescence staining, however, showed that in IAR1170 and IAR-6-1 cells the marginal actin bundle, which is typical of nontransformed IAR-2 cells, disappeared, and the continuous adhesion belt (tangential adherens junctions (AJs)) was replaced by radially oriented E-cadherin–based AJs. Time-lapse imaging of IAR-6-1 cells stably transfected with GFP-E-cadherin revealed that AJs in transformed cells are very dynamic and unstable. The regulation of AJ assembly by Rho family small GTPases was different in nontransformed and in transformed IAR epithelial cells. As our experiments with the ROCK inhibitor Y-27632 and the myosin II inhibitor blebbistatin have shown, the formation and maintenance of radial AJs critically depend on myosin II-mediated contractility. Using the RNAi technique for the depletion of mDia1 and loading cells with N17Rac, we established that mDia1 and Rac are involved in the assembly of tangential AJs in nontransformed epithelial cells but not in radial AJs in transformed cells. Neoplastic transformation changed cell–cell interactions, preventing contact paralysis after the establishment of cell–cell contact and promoting dynamic cell–cell adhesion and motile behavior of cells. It is suggested that the disappearance of the marginal actin bundle and rearrangements of AJs may change the adhesive function of E-cadherin and play an active role in migratory activity of carcinoma cells.     

Molecular Bases of Cell–Cell Junctions Stability and Dynamics

Epithelial cell–cell junctions are formed by apical adherens junctions (AJs), which are composed of cadherin adhesion molecules interacting in a dynamic way with the cortical actin cytoskeleton. Regulation of cell–cell junction stability and dynamics is crucial to maintain tissue integrity and allow tissue remodeling throughout development. Actin filament turnover and organization are tightly controlled together with myosin-II activity to produce mechanical forces that drive the assembly, maintenance, and remodeling of AJs. In this review, we will discuss these three distinct stages in the lifespan of cell–cell junctions, using several developmental contexts, which illustrate how mechanical forces are generated and transmitted at junctions, and how they impact on the integrity and the remodeling of cell–cell junctions.Cell–cell junction formation and remodeling occur repeatedly throughout development. Epithelial cells are linked by apical adherens junctions (AJs) that rely on the cadherin-catenin-actin module. Cadherins, of which epithelial E-cadherin (E-cad) is the most studied, are Ca²⁺-dependent transmembrane adhesion proteins forming homophilic and heterophilic bonds in trans between adjacent cells. Cadherins and the actin cytoskeleton are mutually interdependent (Jaffe et al. 1990; Matsuzaki et al. 1990; Hirano et al. 1992; Oyama et al. 1994; Angres et al. 1996; Orsulic and Peifer 1996; Adams et al. 1998; Zhang et al. 2005; Pilot et al. 2006). This has long been attributed to direct physical interaction of E-cad with β-catenin (β-cat) and of α-catenin (α-cat) with actin filaments (for reviews, see Gumbiner 2005; Leckband and Prakasam 2006; Pokutta and Weis 2007). Recently, biochemical and protein dynamics analyses have shown that such a link may not exist and that instead, a constant shuttling of α-cat between cadherin/β-cat complexes and actin may be key to explain the dynamic aspect of cell–cell adhesion (Drees et al. 2005; Yamada et al. 2005). Regardless of the exact nature of this link, several studies show that AJs are indeed physically attached to actin and that cadherins transmit cortical forces exerted by junctional acto-myosin networks (Costa et al. 1998; Sako et al. 1998; Pettitt et al. 2003; Dawes-Hoang et al. 2005; Cavey et al. 2008; Martin et al. 2008; Rauzi et al. 2008). In addition, physical association depends in part on α-cat (Cavey et al. 2008) and additional intermediates have been proposed to represent alternative missing links (Abe and Takeichi 2008) (reviewed in Gates and Peifer 2005; Weis and Nelson 2006). Although further work is needed to address the molecular nature of cadherin/actin dynamic interactions, association with actin is crucial all throughout the lifespan of AJs. In this article, we will review our current understanding of the molecular mechanisms at work during three different developmental stages of AJs biology: assembly, stabilization, and remodeling, with special emphasis on the mechanical forces controlling AJs integrity and development.     

Cell Cycle–Mediated Regulation of Plant Infection by the Rice Blast Fungus

To gain entry to plants, many pathogenic fungi develop specialized infection structures called appressoria. Here, we demonstrate that appressorium morphogenesis in the rice blast fungus Magnaporthe oryzae is tightly regulated by the cell cycle. Shortly after a fungus spore lands on the rice (Oryza sativa) leaf surface, a single round of mitosis always occurs in the germ tube. We found that initiation of infection structure development is regulated by a DNA replication-dependent checkpoint. Genetic intervention in DNA synthesis, by conditional mutation of the Never-in-Mitosis 1 gene, prevented germ tubes from developing nascent infection structures. Cellular differentiation of appressoria, however, required entry into mitosis because nimA temperature-sensitive mutants, blocked at mitotic entry, were unable to develop functional appressoria. Arresting the cell cycle after mitotic entry, by conditional inactivation of the Blocked-in-Mitosis 1 gene or expression of stabilized cyclinB-encoding alleles, did not impair appressorium differentiation, but instead prevented these cells from invading plant tissue. When considered together, these data suggest that appressorium-mediated plant infection is coordinated by three distinct cell cycle checkpoints that are necessary for establishment of plant disease.     

RGD Peptide–Albumin Conjugate for Endothelization of Electrospun Materials

Russian Journal of Bioorganic Chemistry - To improve the endothelization of 3D matrices produced by electrospinning we propose adding cyclo(RGDfC) peptide conjugated to human serum albumin (HSA)...     

Resistance of Soybean Pectin–Protein Conjugate Pre-Adsorbed to the Air–Water Interface to Displacement by the Competitive Adsorption of Surfactant

Food Biophysics - The naturally occurring soybean pectin–protein conjugate pre-adsorbed to the air–water interface was shown to be displaced competitively from the interface when a...     

Epithelial Cell Adhesion Molecule (Ep-CAM) Modulates Cell–Cell Interactions Mediated by Classic Cadherins

The contribution of noncadherin-type, Ca²⁺-independent cell–cell adhesion molecules to the organization of epithelial tissues is, as yet, unclear. A homophilic, epithelial Ca²⁺-independent adhesion molecule (Ep-CAM) is expressed in most epithelia, benign or malignant proliferative lesions, or during embryogenesis. Here we demonstrate that ectopic Ep-CAM, when expressed in cells interconnected by classic cadherins (E- or N-cadherin), induces segregation of the transfectants from the parental cell type in coaggregation assays and in cultured mixed aggregates, respectively. In the latter assay, Ep-CAM–positive transfectants behave like cells with a decreased strength of cell–cell adhesion as compared to the parental cells. Using transfectants with an inducible Ep-CAM–cDNA construct, we demonstrate that increasing expression of Ep-CAM in cadherin-positive cells leads to the gradual abrogation of adherens junctions. Overexpression of Ep-CAM has no influence on the total amount of cellular cadherin, but affects the interaction of cadherins with the cytoskeleton since a substantial decrease in the detergent-insoluble fraction of cadherin molecules was observed. Similarly, the detergent-insoluble fractions of α- and β-catenins decreased in cells overexpressing Ep-CAM. While the total β-catenin content remains unchanged, a reduction in total cellular α-catenin is observed as Ep-CAM expression increases. As the cadherin-mediated cell–cell adhesions diminish, Ep-CAM–mediated intercellular connections become predominant. An adhesion-defective mutant of Ep-CAM lacking the cytoplasmic domain has no effect on the cadherin-mediated cell–cell adhesions. The ability of Ep-CAM to modulate the cadherin-mediated cell–cell interactions, as demonstrated in the present study, suggests a role for this molecule in development of the proliferative, and probably malignant, phenotype of epithelial cells, since an increase of Ep-CAM expression was observed in vivo in association with hyperplastic and malignant proliferation of epithelial cells.Tissue and organ morphogenesis can be viewed as the result of interactions of various cell populations. One important type of intercellular interaction involved in the processes of tissue morphogenesis, morphogenetic movements of cells, and segregation of cell types, are adhesions mediated by cell adhesion molecules (Steinberg and Pool, 1982; Edelman, 1986; Cunningham, 1995; Takeichi, 1995; Gumbiner, 1996). Except for their direct mechanical role as interconnectors of cells and connectors of cells to substrates, cell adhesion molecules are also believed to be responsible for a variety of dynamic processes including cell locomotion, proliferation, and differentiation. There is also evidence that the adhesion systems within a cell may act as regulators of other cell adhesions, thereby offering a means of signaling that is relevant for rearrangements in cell or tissue organization (Edelman, 1993; Rosales et al., 1995; Gumbiner, 1996).In many tissues, a critical role in the maintenance of multicellular structures is assigned to cadherins, a family of Ca²⁺-dependent, homophilic cell–cell adhesion molecules (Takeichi, 1991, 1995; Gumbiner, 1996). In epithelia this critical role belongs to E-cadherin, which is crucial for the establishment and maintenance of epithelial cell polarity (McNeil et al., 1990; Näthke et al., 1993), morphogenesis of epithelial tissues (Wheelock and Jensen, 1992; Larue et al., 1996), and regulation of cell proliferation and programmed cell death (Hermiston and Gordon, 1995; Hermiston et al., 1996; Takahashi and Suzuki, 1996; Wilding et al., 1996; Zhu and Watt, 1996). Expression of different types of classic cadherin molecules (Nose et al., 1988; Friedlander et al., 1989; Daniel et al., 1995), and even quantitative differences in the levels of the same type of cadherin (Steinberg and Takeichi, 1994), may be responsible for segregation of cell types in epithelial tissues. The phenotype of epithelial cells may be modulated by expression of combinations of different types of cadherins (Marrs et al., 1995; Islam et al., 1996). However, cadherins represent only one of the intercellular adhesion systems that are present in epithelia, along with adhesion molecules of the immunoglobulin superfamily, such as carcinoembryonic antigen (Benchimol et al., 1989), and others. The actual contribution of Ca²⁺-independent nonjunctional adhesion molecules to the formation and maintenance of the epithelial tissue architecture and epithelial cell morphology is not clear.We have recently demonstrated that a 40-kD epithelial glycoprotein, which we have designated epithelial cell adhesion molecule (Ep-CAM)¹ (Litvinov et al., 1994a ), may perform as a homophilic, Ca²⁺-independent intercellular adhesion molecule, capable of mediating cell aggregation, preventing cell scattering, and directing cell segregation. This type I transmembrane glycoprotein consists of two EGF-like domains followed by a cysteine-poor region, a transmembrane domain, and a short (26-amino acid) cytoplasmic tail, and is not structurally related to the four major types of CAMs, such as cadherins, integrins, selectins, and the immunoglobulin superfamily (for review see Litvinov, 1995). Ep-CAM demonstrates adhesion properties when introduced into cell systems that are deficient in intercellular adhesive interactions (Litvinov et al., 1994a ). However, the participation of the Ep-CAM molecule in supporting cell–cell interactions of epithelial cells was not evident (Litvinov et al., 1994b ).Most epithelial cell types coexpress E-cadherin (and sometimes other classic cadherins) and Ep-CAM (for review see Litvinov, 1995) during some stage of embryogenesis. In adult squamous epithelia, which are Ep-CAM negative, de novo expression of this molecule is associated with metaplastic or neoplastic changes. Thus, in ectocervical epithelia, expression of Ep-CAM occurs in early preneoplastic lesions (Litvinov et al., 1996); most squamous carcinomas of the head and neck region are Ep-CAM positive (Quak et al., 1990), and basal cell carcinomas are Ep-CAM positive in contrast to the normal epidermis (Tsubura et al., 1992).In many tumors that express Ep-CAM heterogeneously, an Ep-CAM–positive cell population may be found within an Ep-CAM–negative cell population, with both cell types expressing approximately equal levels of cadherins, as illustrated in Fig. ​Fig.11 A by a case of basal cell carcinoma. In glandular tissues such as gastric epithelium, which are low/ negative for Ep-CAM, expression of Ep-CAM is related to the development of early stages of intestinal metaplasia (our unpublished observation). Even in tissues with relatively high Ep-CAM expression, such as colon, the development of polyps is accompanied by an increase in Ep-CAM expression (Salem et al., 1993). In intestinal metaplasia one may observe Ep-CAM–positive cells bordering morphologically identical normal cells that are Ep-CAM–negative (as illustrated in Fig. ​Fig.11 B) Ep-CAM–positive cells bordering Ep-CAM–negative epithelial cells may also be found in some normal tissues such as hair follicles (Tsubura et al., 1992). Open in a separate windowFigure 1Examples of Ep-CAM expression by some cells within the E-cadherin–positive cell population. (A) Heterogeneous expression of Ep-CAM in a basal cell carcinoma, as detected by immunofluorescent staining with mAb 323/A3 to Ep-CAM (green fluorescence); the red fluorescence indicates the expression of E-cadherin (mAb HECD-1). (B) The de novo expression of Ep-CAM in gastric mucosa in relation to the development of intestinal metaplasia; immunohistochemical staining with mAb 323/A3. Note the bordering Ep-CAM–positive and –negative cells. Bars, 30 μM.From the examples presented, an increased or de novo expression of Ep-CAM is often observed in epithelial tissues in vivo. Expression of an additional molecule that may participate in cell adhesion in the context of other adhesion systems may have certain effects on the cell–cell interactions. Therefore, we have investigated whether the increased/de novo expression of Ep-CAM in epithelial cells (a) has any impact on interactions of positive cells with the parental Ep-CAM–negative cells, and (b) modulates in any way intercellular adhesive interactions of cells interconnected by E-cadherin, which is the major morphoregulatory molecule in epithelia.Here we demonstrate that expression of Ep-CAM by some cells in a mixed cell population expressing classical cadherins induces segregation of the Ep-CAM–positive cells from the parental cell population due to a negative effect on cadherin junctions caused by expression of Ep-CAM. The cadherin-modulating properties observed for Ep-CAM suggest a role for this molecule in the development of a proliferative and metaplastic cell phenotype, and probably in the development and progression of malignancies.     

Drug–DNA Interaction Studies of Acridone-Based Derivatives

N¹⁰-alkylated 2-bromoacridones are a novel series of potent antitumor compounds. DNA binding studies of these compounds were carried out using spectrophotometric titrations, Circular dichroism (CD) measurements using Calf Thymus DNA (CT DNA). The binding constants were identified at a range of K = 0.3 to 3.9 × 10⁵ M^?1 and the percentage of hypochromism from the spectral titrations at 28–54%. This study has identified a compound 9 with the good binding affinity of K = 0.39768 × 10⁵ M^?1 with CT DNA. Molecular dynamics (MD) simulations have investigated the changes in structural and dynamic features of native DNA on binding to the active compound 9. All the synthesized compounds have increased the uptake of Vinblastine in MDR KBCh^R-8-5 cells to an extent of 1.25- to1.9-fold than standard modulator Verapamil of similar concentration. These findings allowed us to draw preliminary conclusions about the structural features of 2-bromoacridones and further chemical enhancement will improve the binding affinity of the acridone derivatives to CT-DNA for better drug–DNA interaction. The molecular modeling studies have shown mechanism of action and the binding modes of the acridones to DNA.     

Golgi-associated cPLA2α Regulates Endothelial Cell–Cell Junction Integrity by Controlling the Trafficking of Transmembrane Junction Proteins

In endothelial cells specifically, cPLA2α translocates from the cytoplasm to the Golgi complex in response to cell confluence. Considering the link between confluence and cell–cell junction formation, and the emerging role of cPLA2α in intracellular trafficking, we tested whether Golgi-associated cPLA2α is involved in the trafficking of junction proteins. Here, we show that the redistribution of cPLA2α from the cytoplasm to the Golgi correlates with adherens junction maturation and occurs before tight junction formation. Disruption of adherens junctions using a blocking anti-VE-cadherin antibody reverses the association of cPLA2α with the Golgi. Silencing of cPLA2α and inhibition of cPLA2α enzymatic activity using various inhibitors result in the diminished presence of the transmembrane junction proteins VE-cadherin, occludin, and claudin-5 at cell–cell contacts, and in their accumulation at the Golgi. Altogether, our data support the idea that VE-cadherin triggers the relocation of cPLA2α to the Golgi and that in turn, Golgi-associated cPLA2α regulates the transport of transmembrane junction proteins through or from the Golgi, thereby controlling the integrity of endothelial cell–cell junctions.