Use of the xCELLigence system for real-time analysis of changes in cellular motility and adhesion in physiological conditions

Luteolin peracetate and gossypolone inhibit immune complex-mediated neutrophil activation in vitro and dermal-epidermal separation in an ex vivo model of epidermolysis bullosa acquisita

Introduction

Natural products have been shown to an important source of therapeutics for human disease. In this study, we aimed to identify natural compounds as potential therapeutics for epidermolysis bullosa acquisita (EBA), an autoimmune disease caused by autoantibodies to type VII collagen (COL7).

Methods

Utilizing an in vitro experimental system, we screened a natural product library composed of 800 pure compounds for their inhibitory effect on COL7-anti-COL7 IgG immune complex (IC)-mediated neutrophil activation and on neutrophil-mediated tissue damage.

Results

Three natural compounds, namely luteolin peracetate, gossypol, and gossypolone were capable in inhibiting the IC-induced neutrophil adhesion and oxygen burst in vitro. Furthermore, luteolin peracetate and gossypolone were able to inhibit the anti-COL7 IgG induced dermal-epidermal separation in an ex vivo model for EBA.

Discussion

In summary, this study demonstrates that luteolin peracetate and gossypolone are potential therapeutics for experimental EBA, which deserves further investigation.

Y, Wang X, He X, Wu X, Xu C, Tang Y, Liu WT, Kong X, Hu L. Bilirubin Improves Gap Junction to Alleviate Doxorubicin-Induced Cardiotoxicity by Regulating AMPK-Axl-SOCS3-Cx43 Axis

Doxorubicin induces severe cardiotoxicity, accompanied by the high level of bilirubin in the blood. The conventional wisdom is that bilirubin is considered as a marker of liver damage. By contrast, here we aim to explore the potential protective effect of bilirubin on doxorubicin-induced cardiotoxicity, and investigate the mechanism for drug development. Doxorubicin was used to establish cardiotoxicity model in vitro and in vivo. The electrocardiogram (ECG), echocardiography and molecular biological methods were used to detect the effects of bilirubin on doxorubicin-induced cardiotoxicity. Consecutive intraperitoneal injection of bilirubin for 7 days significantly attenuated doxorubicin-induced arrhythmia, prolonged survival time and reduced the levels of aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase MB (CK-MB) and α-hydroxybutyrate dehydrogenase (α-HBDH) in mice. Bilirubin also markedly inhibited doxorubicin-induced phosphorylation of c-Jun N-terminal kinase (JNK) and connexin 43 (Cx43), and improved gap junction function in vitro and in vivo. In addition, bilirubin activated adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and induced suppressor of cytokine signaling 3 (SOCS3) expression, which was abolished by Axl inhibition. Moreover, pretreatment with AMPK agonist or AMPK inhibitor could mimic or abolish the cardioprotective effect of bilirubin on H9C2 cells in vitro, respectively. Altogether, bilirubin upregulates gap junctions' function to protect against doxorubicin-induced cardiotoxicity by activating AMPK-Axl-SOCS3 signaling axis. We enrich the physiological function of bilirubin, and provide theoretical support for drug development.

Complex Interplay of Genes Underlies Invasiveness in Fibrosarcoma Progression Model

Sarcomas are a heterogeneous group of mesenchymal tumours, with a great variability in their clinical behaviour. While our knowledge of sarcoma initiation has advanced rapidly in recent years, relatively little is known about mechanisms of sarcoma progression. JUN-murine fibrosarcoma progression series consists of four sarcoma cell lines, JUN-1, JUN-2, JUN-2fos-3, and JUN-3. JUN-1 and -2 were established from a single tumour initiated in a H2K/v-jun transgenic mouse, JUN-3 originates from a different tumour in the same animal, and JUN-2fos-3 results from a targeted in vitro transformation of the JUN-2 cell line. The JUN-1, -2, and -3 cell lines represent a linear progression from the least transformed JUN-2 to the most transformed JUN-3, with regard to all the transformation characteristics studied, while the JUN-2fos-3 cell line exhibits a unique transformation mode, with little deregulation of cell growth and proliferation, but pronounced motility and invasiveness. The invasive sarcoma sublines JUN-2fos-3 and JUN-3 show complex metabolic profiles, with activation of both mitochondrial oxidative phosphorylation and glycolysis and a significant increase in spared respiratory capacity. The specific transcriptomic profile of invasive sublines features very complex biological relationships across the identified genes and proteins, with accentuated autocrine control of motility and angiogenesis. Pharmacologic inhibition of one of the autocrine motility factors identified, Ccl8, significantly diminished both motility and invasiveness of the highly transformed fibrosarcoma cell. This progression series could be greatly valuable for deciphering crucial aspects of sarcoma progression and defining new prognostic markers and potential therapeutic targets.

[Astroglia-mediated regulation of cell development in the model of neurogenic niche in vitro treated with Aβ1-42]

Neurogenesis is a complex process which governs embryonic brain development and is importants for brain plasticity throughout the whole life. Postnatal neurogenesis occurs in neurogenic niches that regulate the processes of proliferation and differentiation of stem and progenitor cells under the action of stimuli that trigger the mechanisms of neuroplasticity. Cells of glial and endothelial origin are the key regulators of neurogenesis. It is known that physiological neurogeneses is crucial for memory formation, whereas reparative neurogenesis provides partial repair of altered brain structure and compensation of neurological deficits caused by brain injury. Dysregulation of neurogenesis is a characteristics of various neurodevelopmental and neurodegenerative diseases, particularly, Alzheimer's disease which is very important medical and social problem. In the in vitro model of the neurogenic niche using hippocampal neurospheres as a source of stem/progenitor cells and astrocytes, we studied effects of astrocyte activation on the expression of markers of different stages of cell proliferation and differentiation. We found that aberrant mechanisms of development of stem and progenitor cells, caused by the beta-amyloid (Aβ1-42), can be partially restored by targeted activation of GFAP-expressing cells in the neurogenic niche.

Real-time detection of antibiotics cytotoxicity in rabbit periosteal cells using microfluidic devices with comparison to conventional culture assays

Background

Local antibiotic application has been widely used in orthopedic surgery. The dose-related toxicity of antibiotics towards periosteal tissues and resulting effects on osteogenic expression are yet to be studied.

Methods

Periosteal cells harvested from the medial tibia of New Zealand White rabbits were used. A seeding density of 5 × 10³ cells/cm² was determined to be optimal for testing in the pilot study; the cells were cultured in xCELLigence 96-well plates. Microfluidic impedance analyzers were used to monitor cellular proliferation in microfluidic culture systems with exposure to three different concentrations (10 μg/mL, 100 μg/mL, and 1000 μg/mL) of cefazolin, ciprofloxacin, and vancomycin, respectively. The correlation of cell index at day 7 with optical density values from WST-1 assays using conventional cultures was evaluated by calculating the Pearson’s coefficient. RNA analysis was performed to investigate the expression of osteogenic markers in the cultured cells, including core-binding factor alpha 1 (Cbfa1), osteopontin (OPN), and osteopontin promoter (OPNp), relative to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as the endogenous control.

Results

A significant dose-related inhibition of cell index was found for all the 3 antibiotics, whereas the WST-1 assays showed a significant dose-related inhibition of cellular proliferation only at a high dose of cefazolin (1000 μg/mL) and medium-to-high dose of ciprofloxacin (100 μg/mL and 1000 μg/mL). Pearson’s coefficient analysis indicated a high correlation between the cell index and optical density values of WST-1 assays only for medium and high doses of ciprofloxacin (100 μg/mL and 1000 μg/mL); a moderate correlation was seen for cefazolin, and a low dose of ciprofloxacin (10 μg/mL). RNA analysis confirmed significant dose-related inhibition of cfba1, OPN, and OPNp expression by all three antibiotics.

Conclusion

With optimal seeding amounts, rabbit periosteal cells can be dynamically monitored in the xCELLigence microfluidic system. Dose-related inhibition of cellular proliferation and osteogenic expression was found after exposure to cefazolin and ciprofloxacin. By providing real-time detection and exhibiting comparable correlation, microfluidic impedance-based analyzer is a feasible alternative to the conventional WST-1 assays.

Comparison of the in vitro cytotoxicity among phospholipid-based parenteral drug delivery systems: Emulsions, liposomes and aqueous lecithin dispersions (WLDs)

Lecithin and isolated phospholipids (mainly phosphatidylcholine) have been used for years as pharmaceutical excipients in parenteral formulations: submicron emulsions, liposomes and mixed micelles. Under development are also other lecithin-based drug delivery systems, e.g. aqueous lecithin dispersions (WLDs). The aim of the study was to investigate the properties and potential cytotoxicity of 7 different phospholipid-based dispersions intended for parenteral administration: emulsions, liposomes and WLDs. Each formulation contained egg phosphatidylcholine (PC) in the concentration range of 0.6-5.0%, and to some formulations other surfactants, such as polysorbate 80 (P80), Solutol HS 15 (HS) and cholesterol (Ch) were added. Particles in all dispersions were homogenous (PDI < 0.26) and submicron in size (Z-average in the range of approx. 100-260 nm). The cytotoxicity of all tested formulations was evaluated by means of 3 independent methods: a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, a real-time xCELLigence (RTCA) system, and a flow cytometry analysis, using two cell lines: human embryonic kidney 293 (HEK-293) and human promyelocytic leukaemia (HL-60). The results indicated that regardless of the test method and cell line type, the cytotoxicity of all formulations was low, especially when dispersions diluted to concentrations of =10% were tested. A more pronounced cytotoxic effect was noticed only for the following formulations: E-P80 (emulsion containing P80), WLD (unbuffered aqueous lecithin dispersion) and L-Ch (liposomes containing Ch), tested as less diluted (concentration 10% or 25%). IC50 values measured for these dispersions (on HL-60 cells) amounted to: 10.4 ± 0.5% (v/v), 14.4 ± 0.2% (v/v) and 24.2 ± 0.6% (v/v), respectively. Our investigation confirmed the biocompatibility of all tested phospholipid-based formulations: emulsions, liposomes and also newly-developed WLDs, which can be considered as safe parenteral drug carriers.

Parthenolide Inhibits STAT3 Signaling by Covalently Targeting Janus Kinases

Aberrant activations of the STAT3 (signal transducer and activator of transcription 3) signaling pathway are associated with cancer and inflammatory diseases. Three of the four Janus kinases, JAK1, JAK2, and Tyk2, are the major upstream kinases of STAT3 in responses to cytokine stimulations. Among them, JAK2 is the key kinase in the IL-6-induced STAT3 phosphorylation. Here we report the mechanisms of a natural compound parthenolide from the medicinal herb Feverfew in regulating the JAK/STAT3 signaling. We found that parthenolide was a potent inhibitor of JAKs. It covalently modified the Cys178, Cys243, Cys335, and Cys480 of JAK2 and suppressed its kinase activity. It also interacted with other JAKs in a similar fashion. The binding of parthenolide to JAKs was selective. It preferentially bound to the JAKs, but not to the abundant proteins, such as tubulin and actin. Parthenolide also induced reactive oxygen species (ROS), but the increased ROS did not seem to contribute to the inhibition of JAK/STAT3 signaling. Furthermore, parthenolide inhibited the IL-6-induced cancer cell migration and preferentially inhibited the growth of cancer cells that had constitutively activated STAT3. Our study suggests a novel strategy to inactivate JAKs and provides a promising anti-inflammation and anticancer drug candidate.

Nephronectin is Correlated with Poor Prognosis in Breast Cancer and Promotes Metastasis via its Integrin-Binding Motifs

Most cancer patients with solid tumors who succumb to their illness die of metastatic disease. While early detection and improved treatment have led to reduced mortality, even for those with metastatic cancer, some patients still respond poorly to treatment. Understanding the mechanisms of metastasis is important to improve prognostication, to stratify patients for treatment, and to identify new targets for therapy. We have shown previously that expression of nephronectin (NPNT) is correlated with metastatic propensity in breast cancer cell lines. In the present study, we provide a comprehensive analysis of the expression pattern and distribution of NPNT in breast cancer tissue from 842 patients by immunohistochemical staining of tissue microarrays from a historic cohort. Several patterns of NPNT staining were observed. An association between granular cytoplasmic staining (in <10% of tumor cells) and poor prognosis was found. We suggest that granular cytoplasmic staining may represent NPNT-positive exosomes. We found that NPNT promotes adhesion and anchorage-independent growth via its integrin-binding and enhancer motifs and that enforced expression in breast tumor cells promotes their colonization of the lungs. We propose that NPNT may be a novel prognostic marker in a subgroup of breast cancer patients.

Neutrophil Adhesion Is a Prerequisite for Antibody-Mediated Proteolytic Tissue Damage in Experimental Models of Epidermolysis Bullosa Acquisita

Although uncontrolled proteolytic activity mediated by activated neutrophils is a major reason for tissue damage, therapeutic approaches using protease inhibitors are inefficient. Here, we investigated the role of the immune complex-induced neutrophil adhesion and protease release in tissue damage. We show both in vitro and in vivo that immune complex-mediated neutrophil adhesion to the target tissue depends on β₂ integrins. Without affecting elastase or reactive oxygen species release, blocking of adhesion drastically inhibited tissue damage in an experimental model of autoantibody-mediated skin blistering disease. By using a cell-bound fluorescent resonance energy transfer-based elastase sensor, we detected elastase enzyme activity on the surface of adherent cells resistant to protease inhibitors. Inhibitor resistance was lost by CD18 blockade or deficiency in vitro and in vivo. Immune complex-induced neutrophil adhesion created an enclosed protected space between the cell and its target structure where proteinases and reactive oxygen species can execute their tissue-damaging effect. Because immune complex-induced neutrophil adhesion represents an indispensable step for tissue damage of many diseases, our findings may facilitate the development of strategies for the treatment of such disorders.

MYCN and HDAC5 transcriptionally repress CD9 to trigger invasion and metastasis in neuroblastoma

The systemic and resistant nature of metastatic neuroblastoma renders it largely incurable with current multimodal treatment. Clinical progression stems mainly from the increasing burden of metastatic colonization. Therapeutically inhibiting the migration-invasion-metastasis cascade would be of great benefit, but the mechanisms driving this cycle are as yet poorly understood. In-depth transcriptome analyses and ChIP-qPCR identified the cell surface glycoprotein, CD9, as a major downstream player and direct target of the recently described GRHL1 tumor suppressor. CD9 is known to block or facilitate cancer cell motility and metastasis dependent upon entity. High-level CD9 expression in primary neuroblastomas correlated with patient survival and established markers for favorable disease. Low-level CD9 expression was an independent risk factor for adverse outcome. MYCN and HDAC5 colocalized to the CD9 promoter and repressed transcription. CD9 expression diminished with progressive tumor development in the TH-MYCN transgenic mouse model for neuroblastoma, and CD9 expression in neuroblastic tumors was far below that in ganglia from wildtype mice. Primary neuroblastomas lacking MYCN amplifications displayed differential CD9 promoter methylation in methyl-CpG-binding domain sequencing analyses, and high-level methylation was associated with advanced stage disease, supporting epigenetic regulation. Inducing CD9 expression in a SH-EP cell model inhibited migration and invasion in Boyden chamber assays. Enforced CD9 expression in neuroblastoma cells transplanted onto chicken chorioallantoic membranes strongly reduced metastasis to embryonic bone marrow. Combined treatment of neuroblastoma cells with HDAC/DNA methyltransferase inhibitors synergistically induced CD9 expression despite hypoxic, metabolic or cytotoxic stress. Our results show CD9 is a critical and indirectly druggable suppressor of the invasion-metastasis cycle in neuroblastoma.

Low FAT4 expression is associated with a poor prognosis in gastric cancer patients

In this study, we investigated the role of Fat atypical cadherin 4 (FAT4) in gastric cancer (GC) progression. Immunohistochemical analysis showed lower FAT4 expression in tumor tissues from GC patients than in normal gastric epithelium. Lower FAT4 expression was associated with poor prognosis, tumor size and invasion, and lymph node and distant metastases. Multivariate analysis showed that TNM stage, lymph node and distant metastases, Lauren classification, and FAT4 expression were independent prognostic factors in GC. Methylation-specific PCR analysis showed increased FAT4 promoter methylation in GC tumor tissues and cell lines. Higher FAT4 promoter methylation was associated with low FAT4 expression and a poor prognosis. BGC-823 cells showed increased FAT4 expression upon treatment with 5-azacytidine, demethylating agent. FAT4 knockdown in BGC-823 cells led to increased cell proliferation, migration and invasiveness. Moreover, xenografts of BGC-823 cells with FAT4 knockdown showed enhanced tumor growth and metastasis in nude mice. These findings demonstrate that low FAT4 expression is associated with a poor prognosis in GC patients.

Comparison between xCELLigence biosensor technology and conventional cell culture system for real-time monitoring human tenocytes proliferation and drugs cytotoxicity screening

Background

Local injections of anesthetics, NSAIDs, and corticosteroids for tendinopathies are empirically used. They are believed to have some cytotoxicity toward tenocytes. The maximal efficacy dosages of local injections should be determined. A commercial 2D microfluidic xCELLigence system had been developed to detect real-time cellular proliferation and their responses to different stimuli and had been used in several biomedical applications. The purpose of this study is to determine if human tenocytes can successfully proliferate inside xCELLigence system and the result has high correlation with conventional cell culture methods in the same condition.

Methods

First passage of human tenocytes was seeded in xCELLigence and conventional 24-well plates. Ketorolac tromethamine, bupivacaine, methylprednisolone, and betamethasone with different concentrations (100, 50, and 10% diluted of clinical usage) were exposed in both systems. Gene expression of type I collagen, type III collagen, tenascin-C, decorin, and scleraxis were compared between two systems.

Results

Human tenocytes could proliferate both in xCELLigence and conventional cell culture systems. Cytotoxicity of each drug revealed dose-dependency when exposed to tenocytes in both systems. Significance was found between groups. All the four drugs had comparable cytotoxicity in their 100% concentration. When 50% concentration was used, betamethasone had a relatively decreased cytotoxicity among them in xCELLigence but not in conventional culture. When 10% concentration was used, betamethasone had the least cytotoxicity. Strong and positive correlation was found between cell index of xCELLigence and result of WST-1 assay (Pearson’s correlation [r] = 0.914). Positive correlation of gene expression between tenocytes in xCELLigence and conventional culture was also observed. Type I collagen: [r] = 0.823; type III collagen: [r] = 0.899; tenascin-C: [r] = 0.917; decorin: [r] = 0.874; and scleraxis: [r] = 0.965.

Conclusions

Human tenocytes could proliferate inside xCELLigence system. These responses varied when tenocytes were exposed to different concentrations of ketorolac tromethamine, bupivacaine, methylprednisolone, and betamethasone. The result of cell proliferation and gene expression of tenocytes in both xCELLigence and conventional culture system is strongly correlated.

Clinical relevance

xCELLigence culture system may replace conventional cell culture, which made real-time tenocyte proliferation monitoring possible.

L1CAM drives oncogenicity in esophageal squamous cell carcinoma by stimulation of ezrin transcription

L1 cell adhesion molecule (L1CAM) is highly expressed in various types of human cancers, displaying yet unknown molecular mechanisms underlying their oncogenic potential. Here, we found that L1CAM expression was significantly increased in esophageal squamous cell carcinoma (ESCC; n = 157) lesions compared with non-cancerous tissues. High tumorous L1CAM expression significantly correlated with reduced overall survival. Experimentally, L1CAM knockdown led to decreased cell growth, migration, and invasiveness in vitro, whereas overexpression of L1CAM showed the opposite effect. In nude mice, L1CAM depletion attenuated tumorigenesis and ability to penetrate the tissues surrounding ESCC cells. Gene set enrichment analysis (GSEA) and SubpathwayMiner analysis on gene expression profiles (microarray data on ESCC tissues, GSE53625; cDNA microarray data on L1CAM-knockdown ESCC cell line, GSE86268) suggested that L1CAM-co-expression genes were related to cell motility, cell proliferation, and regulation of actin cytoskeleton, validating the above experimental findings. Further mechanistical analysis showed that L1CAM upregulated the expression of the cytoskeletal protein ezrin via activating integrin β1/MAPK/ERK/AP1 signaling and thus led to the malignant phenotypes of ESCC cells. Together, our findings suggest that L1CAM may be employed as a valuable prognosis marker and a therapeutic target for ESCC patients and that L1CAM promotes ESCC tumorigenicity by upregulating ezrin expression.

KEY MESSAGES

L1CAM promotes growth and invasiveness of ESCC cells in vitro and in vivo. L1CAM upregulates the expression of ezrin by integrin α5β1/MAPK/ERK/AP1 pathway. Ezrin is a key downstream effector in the L1CAM-promoted malignant phenotypes. High expression levels of both L1CAM and ezrin significantly correlated with reduced overall survival. Nuclear L1CAM is an independent prognosis marker for esophageal squamous cell carcinoma.

KDM4A regulates HIF-1 levels through H3K9me3

Regions of hypoxia (low oxygen) occur in most solid tumours and cells in these areas are the most aggressive and therapy resistant. In response to decreased oxygen, extensive changes in gene expression mediated by Hypoxia-Inducible Factors (HIFs) contribute significantly to the aggressive hypoxic tumour phenotype. In addition to HIFs, multiple histone demethylases are altered in their expression and activity, providing a secondary mechanism to extend the hypoxic signalling response. In this study, we demonstrate that the levels of HIF-1α are directly controlled by the repressive chromatin mark, H3K9me3. In conditions where the histone demethylase KDM4A is depleted or inactive, H3K9me3 accumulates at the HIF-1α locus, leading to a decrease in HIF-1α mRNA and a reduction in HIF-1α stabilisation. Loss of KDM4A in hypoxic conditions leads to a decreased HIF-1α mediated transcriptional response and correlates with a reduction in the characteristics associated with tumour aggressiveness, including invasion, migration, and oxygen consumption. The contribution of KDM4A to the regulation of HIF-1α is most robust in conditions of mild hypoxia. This suggests that KDM4A can enhance the function of HIF-1α by increasing the total available protein to counteract any residual activity of prolyl hydroxylases.

Human salivary peptide histatin-1 stimulates epithelial and endothelial cell adhesion and barrier function

Histatins are multifunctional histidine-rich peptides secreted by the salivary glands and exclusively present in the saliva of higher primates, where they play a fundamental role in the protection of the oral cavity. Our previously published results demonstrated that histatin-1 (Hst1) promotes cell-substrate adhesion in various cell types and hinted that it could also be involved in cell-cell adhesion, a process of fundamental importance to epithelial and endothelial barriers. Here we explore the effects of Hst1 on cellular barrier function. We show that Hst1 improved endothelial barrier integrity, decreased its permeability for large molecules, and prevented translocation of bacteria across epithelial cell layers. These effects are mediated by the adherens junction protein E-cadherin (E-cad) and by the tight junction protein zonula occludens 1, as Hst1 increases the levels of zonula occludens 1 and of active E-cad. Hst1 may also promote epithelial differentiation as Hst1 induced transcription of the epithelial cell differentiation marker apolipoprotein A-IV (a downstream E-cad target). In addition, Hst1 counteracted the effects of epithelial-mesenchymal transition inducers on the outgrowth of oral cancer cell spheroids, suggesting that Hst1 affects processes that are implicated in cancer progression.-Van Dijk, I. A., Ferrando, M. L., van der Wijk, A.-E., Hoebe, R. A., Nazmi, K., de Jonge, W. J., Krawczyk, P. M., Bolscher, J. G. M., Veerman, E. C. I., Stap, J. Human salivary peptide histatin-1 stimulates epithelial and endothelial cell adhesion and barrier function.

Human gingival fibroblast response to enamel matrix derivative, porcine recombinant 21.3-kDa amelogenin and 5.3-kDa tyrosine-rich amelogenin peptide

Enamel matrix derivative (EMD) containing a variety of protein fractions has been used for periodontal tissue regeneration. It is suggested that the proteins contained in EMD positively influence gingival fibroblasts migration and proliferation. Effects of EMD as well as of porcine recombinated 21.3-kDa amelogenin (prAMEL) and 5.3-kDa tyrosine-rich amelogenin peptide (prTRAP) on human gingival fibroblast (HGF-1, ATCC; USA) cell line were investigated. Real-time cell analysis (xCELLigence system; Roche Applied Science) was performed to determine the effects of EMD, prAMEL and prTRAP (12.5–50 μg/mL) on HGF-1 cell proliferation and migration. The effect of treatment on cell cycle was determined using flow cytometry. EMD significantly increased HGF-1 cell proliferation after 24- and 48-h incubation. Individually, prAMEL and prTRAP also increased HGF-1 cell proliferation; however, the difference was significant only for prAMEL 50 µg/mL. prAMEL and TRAP significantly increased HGF-1 cell migration after 60- and 72-h incubation. Cell cycle analysis showed significant decrease of the percentage of cells in the G0/G1 phase and a buildup of cells in the S and M phase observed after EMD and prAMEL stimulation. This process was ligand and concentration-dependent. The various molecular components in the enamel matrix derivative might contribute to the reported effects on gingival tissue regeneration; however, biologic effects of prAMEL and prTRAP individually were different from that of EMD.

Oncolytic Group B Adenovirus Enadenotucirev Mediates Non-apoptotic Cell Death with Membrane Disruption and Release of Inflammatory Mediators

Enadenotucirev (EnAd) is a chimeric group B adenovirus isolated by bioselection from a library of adenovirus serotypes. It replicates selectively in and kills a diverse range of carcinoma cells, shows effective anticancer activity in preclinical systems, and is currently undergoing phase I/II clinical trials. EnAd kills cells more quickly than type 5 adenovirus, and speed of cytotoxicity is dose dependent. The EnAd death pathway does not involve p53, is predominantly caspase independent, and appears to involve a rapid fall in cellular ATP. Infected cells show early loss of membrane integrity; increased exposure of calreticulin; extracellular release of ATP, HSP70, and HMGB1; and influx of calcium. The virus also causes an obvious single membrane blister reminiscent of ischemic cell death by oncosis. In human tumor biopsies maintained in ex vivo culture, EnAd mediated release of pro-inflammatory mediators such as TNF-α, IL-6, and HMGB1. In accordance with this, EnAd-infected tumor cells showed potent stimulation of dendritic cells and CD4+ T cells in a mixed tumor-leukocyte reaction in vitro. Whereas many viruses have evolved for efficient propagation with minimal inflammation, bioselection of EnAd for rapid killing has yielded a virus with a short life cycle that combines potent cytotoxicity with a proinflammatory mechanism of cell death.

Cell-impedance-based label-free technology for the identification of new drugs

INTRODUCTION

Drug discovery has progressed from relatively simple binding or activity screening assays to high-throughput screening of sophisticated compound libraries with emphasis on miniaturization and automation. The development of functional assays has enhanced the success rate in discovering novel drug molecules. Many technologies, originally based on radioactive labeling, have sequentially been replaced by methods based on fluorescence labeling. Recently, the focus has switched to label-free technologies in cell-based screening assays. Areas covered: Label-free, cell-impedance-based methods comprise of different technologies including surface plasmon resonance, mass spectrometry and biosensors applied for screening of anticancer drugs, G protein-coupled receptors, receptor tyrosine kinase and virus inhibitors, drug and nanoparticle cytotoxicity. Many of the developed methods have been used for high-throughput screening in cell lines. Cell viability and morphological damage prediction have been monitored in three-dimensional spheroid human HT-29 carcinoma cells and whole Schistosomula larvae. Expert opinion: Progress in label-free, cell-impedance-based technologies has facilitated drug screening and may enhance the discovery of potential novel drug molecules through, and improve target molecule identification in, alternative signal pathways. The variety of technologies to measure cellular responses through label-free cell-impedance based approaches all support future drug development and should provide excellent assets for finding better medicines.

Preclinical testing of an Atr inhibitor demonstrates improved response to standard therapies for esophageal cancer

BACKGROUND AND PURPOSE

Esophageal cancer has a persistently low 5-year survival rate and has recently been classified as a cancer of unmet need by Cancer Research UK. Consequently, new approaches to therapy are urgently required. Here, we tested the hypothesis that an ATR inhibitor, VX-970, used in combination with standard therapies for esophageal cancer could improve treatment outcome.

MATERIAL AND METHODS

Using esophageal cancer cell lines we evaluated the efficacy of combining VX-970 with cisplatin and carboplatin in vitro and with radiation in vitro and in vivo. Radiation experiments were also carried out in hypoxic conditions to mimic the tumor microenvironment.

RESULTS

Combining VX-970 with cisplatin, carboplatin and radiation increased tumor cell kill in vitro. A significant tumor growth delay was observed when VX-970 was combined with radiotherapy in vivo.

CONCLUSIONS

VX-970 is an effective chemo/radiosensitizer which could be readily integrated in the current treatment paradigm to improve the treatment response in esophageal cancer and we plan to test it prospectively in the forthcoming phase I dose escalation safety study combining the ATR inhibitor VX-970 with chemoradiotherapy in esophageal cancer (EudraCT number: 2015-003965-27).

Reuse of E-plate cell sensor arrays in the xCELLigence Real-Time Cell Analyzer

The xCELLigence Real-Time Cell Analyzer (RTCA) is a non-invasive, impedence-based biosensor system that can measure cell viability, migration, growth, spreading, and proliferation. Changes in cell morphology and behavior are continuously monitored in real time using microelectronics located in the wells of RTCA E-plates. According to the manufacturer's recommendation, E-plates are single-use and disposable. Here, we show that E-plates can be regenerated and reused several times without significantly effecting experimental results.

Synergistic effects of combined treatment with histone deacetylase inhibitor suberoylanilide hydroxamic acid and TRAIL on human breast cancer cells

Previous studies showed that either histone deacetylase (HDAC) inhibitors or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can induce apoptosis in tumor cells including breast cancer. However, the underling mechanisms of combining HDAC inhibitors with TRAIL in the treatment of breast cancer are poorly understood. In this study, we determined the ability of SAHA and TRAIL as single agents or in combination to inhibit the growth and survival of MCF-7 and MDA-MB-231 breast cancer cells. Our results demonstrate that the distinct effects of SAHA or TRAIL individually and in combination on the proliferation, cell viability, apoptosis, cell cycle distribution, and morphological changes of MDA-MB-231 and MCF-7 cells. We further determined the different effects of SAHA or TRAIL alone and combining SAHA with TRAIL on the expression of a number of apoptosis-related molecules, cell cycle, growth factors and their receptors in cancer cells. Our results demonstrated that the combinatorial treatment of SAHA and TRAIL may target multiple pathways and serve as an effective therapeutic strategy against breast cancer. An improved understanding of the molecular mechanisms may facilitate either SAHA or TRAIL targeted use and the selection of suitable combinations.

High throughput toxicity screening and intracellular detection of nanomaterials

With the growing numbers of nanomaterials (NMs), there is a great demand for rapid and reliable ways of testing NM safety—preferably using in vitro approaches, to avoid the ethical dilemmas associated with animal research. Data are needed for developing intelligent testing strategies for risk assessment of NMs, based on grouping and read‐across approaches. The adoption of high throughput screening (HTS) and high content analysis (HCA) for NM toxicity testing allows the testing of numerous materials at different concentrations and on different types of cells, reduces the effect of inter‐experimental variation, and makes substantial savings in time and cost. HTS/HCA approaches facilitate the classification of key biological indicators of NM‐cell interactions. Validation of in vitroHTS tests is required, taking account of relevance to in vivo results. HTS/HCA approaches are needed to assess dose‐ and time‐dependent toxicity, allowing prediction of in vivo adverse effects. Several HTS/HCA methods are being validated and applied for NM testing in the FP7 project NANoREG, including Label‐free cellular screening of NM uptake, HCA, High throughput flow cytometry, Impedance‐based monitoring, Multiplex analysis of secreted products, and genotoxicity methods—namely High throughput comet assay, High throughput in vitro micronucleus assay, and γH2AX assay. There are several technical challenges with HTS/HCA for NM testing, as toxicity screening needs to be coupled with characterization of NMs in exposure medium prior to the test; possible interference of NMs with HTS/HCA techniques is another concern. Advantages and challenges of HTS/HCA approaches in NM safety are discussed. WIREs Nanomed Nanobiotechnol 2017, 9:e1413. doi: 10.1002/wnan.1413

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MicroRNA-215 Regulates Fibroblast Function: Insights from a Human Fibrotic Disease

MicroRNAs are implicated in the regulation of gene expression via various mechanisms in health and disease, including fibrotic processes. Pterygium is an ocular surface condition characterized by abnormal fibroblast proliferation and matrix deposition. We aimed to investigate the role of microRNAs in pterygium and understand the relevant cellular and molecular mechanisms. To achieve this objective, a combination of approaches using surgically excised paired human pterygium and conjunctival tissues as well as cultured primary fibroblast cells from tissue explants were evaluated. Fibroblast dysfunction has been shown to play a central role in pterygium pathology. Here we show that miR-215, among a few others, was down-regulated (2-fold) in pterygium compared to control, and this was consistent in microarray, real-time PCR and fluorescent in-situ hybridization. The effects of increased miR-215 were investigated by adding exogenous miR-215 to fibroblasts, and this showed a decrease in cell proliferation but no significant apoptosis compared to control. Further cell cycle analysis showed that miR-215 depressed progression of cells at G1/S as well as G2/M. A few cell cycle related transcripts were downregulated (2.2-4.5-fold) on addition of miR-215: Mcm3, Dicer1, Cdc25A, Ick, Trip13 and Mcm10. Theoretic binding energies were used to predict miR-215 binding targets and luciferase reporter studies confirmed Mcm10 and Cdc25A as direct targets. In summary, mir-215 could play a role in inhibiting fibroblast proliferation in ocular surface conjunctiva. Dampening of this mir-215 could result in increased fibroblast cell cycling and proliferation, with possibly increased fibroblastic production of matrix, inducing pterygium formation.

Real Time Monitoring of Inhibition of Adipogenesis and Angiogenesis by (-)-Epigallocatechin-3-Gallate in 3T3-L1 Adipocytes and Human Umbilical Vein Endothelial Cells

Little is known about the effect of (−)-epigallocatechin-3-gallate (EGCG) on angiogenesis in adipocytes. We aimed to test the effect of EGCG on the expression of vascular endothelial growth factor (VEGF) in adipocytes. The levels of VEGF secretion, the expression of VEGF message ribonucleic acid (mRNA) and VEGF protein in 3T3-L1 cells were measured by enzyme linked immunosorbent assay (ELISA), real time polymerase chain reaction (PCR), and immunofluorescence staining, respectively. The xCELLigence real time cell analysis system was used to study the growth and differentiation of 3T3-L1 preadipocytes. A coculture system was used to test the effects of 3T3-L1 cells on proliferation of human umbilical vein endothelial cells (HUVECs). The conditioned media derived from 3T3-L1 cells treated with or without EGCG was used to culture the HUVECs for a tube formation assay. Peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα), two transcription factors related to both adipogenesis and angiogenesis, were examined to explore the potential mechanism. We found that all the three measurements of VEGF expression in adipocytes (mRNA, protein and secretion in media) were reduced after EGCG treatment. The growth of HUVECs co-cultured with 3T3-L1 cells was significantly increased and the conditioned media from EGCG treated 3T3-L1 adipocytes inhibited tube formation in HUVECs. Both PPARγ and C/EBPα expression in adipocytes were decreased with EGCG treatment. In conclusion, findings from this study suggest that EGCG may inhibit angiogenesis by regulating VEGF expression and secretion in adipocytes.

Staphylococcus aureus and MRSA Growth and Biofilm Formation after Treatment with Antibiotics and SeNPs

Methicillin-resistant Staphylococcus aureus (MRSA) is a dangerous pathogen resistant to β-lactam antibiotics. Due to its resistance, it is difficult to manage the infections caused by this strain. We examined this issue in terms of observation of the growth properties and ability to form biofilms in sensitive S. aureus and MRSA after the application of antibiotics (ATBs)-ampicillin, oxacillin and penicillin-and complexes of selenium nanoparticles (SeNPs) with these ATBs. The results suggest the strong inhibition effect of SeNPs in complexes with conventional ATBs. Using the impedance method, a higher disruption of biofilms was observed after the application of ATB complexes with SeNPs compared to the group exposed to ATBs without SeNPs. The biofilm formation was intensely inhibited (up to 99%±7% for S. aureus and up to 94%±4% for MRSA) after application of SeNPs in comparison with bacteria without antibacterial compounds whereas ATBs without SeNPs inhibited S. aureus up to 79%±5% and MRSA up to 16%±2% only. The obtained results provide a basis for the use of SeNPs as a tool for the treatment of bacterial infections, which can be complicated because of increasing resistance of bacteria to conventional ATB drugs.

A recombinant fusion protein derived from dog hookworm inhibits autoantibody-induced dermal-epidermal separation ex vivo

The proteins secreted by parasitic nematodes are evolutionarily optimized molecules with unique capabilities of suppressing the immune response of the host organism. Neutrophil inhibitory factor (NIF), which is secreted by the dog hookworm Ancylostoma caninum, binds to the β2 integrin CD11b/CD18, which is expressed on human neutrophils, eosinophils, monocytes and macrophages and inhibits neutrophil-dependent lung injury and neutrophil invasion of ischaemic brain tissue. Neutrophils are key players in the pathogenesis of subepidermal autoimmune blistering diseases (sAIBDs), and their pathogenic activities are crucially dependent on β2 integrin functionality. Based on the template of single-stranded, dimerizing antibody derivatives, which are already used in cancer treatment, we designed a novel biologic, NIF-IGHE-CH4, comprising NIF and the dimerizing but otherwise inert constant heavy subdomain 4 (CH4) of human IgE (IGHE). This molecule was evaluated in a variety of in vitro assays, demonstrating its ability to inhibit pathogenically relevant neutrophil functions such as migration, adhesion and spreading, and release of reactive oxygen species. Finally, we confirmed that NIF-IGHE-CH4 inhibits blister formation in an ex vivo assay of sAIBD. These results suggest that NIF-IGHE-CH4 is a novel potential anti-inflammatory drug for the treatment of neutrophil-mediated diseases such as sAIBDs. This study promotes the drugs from bugs concept and encourages further research and development focused on turning parasite proteins into useful anti-inflammatory biologics.

Wnt/β-catenin pathway involvement in ionizing radiation-induced invasion of U87 glioblastoma cells

BACKGROUND

Radiotherapy has been reported to promote the invasion of glioblastoma cells; however, the underlying mechanisms remain unclear. Here, we investigated the role of the Wnt/β-catenin pathway in radiation-induced invasion of glioblastoma cells.

METHODS

U87 cells were irradiated with 3 Gy or sham irradiated in the presence or absence of the Wnt/β-catenin pathway inhibitor XAV 939. Cell invasion was determined by an xCELLigence real-time cell analyser and matrigel invasion assays. The intracellular distribution of β-catenin in U87 cells with or without irradiation was examined by immunofluorescence and Western blotting of nuclear fractions. We next investigated the effect of irradiation on Wnt/β-catenin pathway activity using TOP/FOP flash luciferase assays and quantitative polymerase chain reaction analysis of β-catenin target genes. The expression levels and activities of two target genes, matrix metalloproteinase (MMP)-2 and MMP-9, were examined further by Western blotting and zymography.

RESULTS

U87 cell invasiveness was increased significantly by ionizing radiation. Interestingly, ionizing radiation induced nuclear translocation and accumulation of β-catenin. Moreover, we found increased β-catenin/TCF transcriptional activities, followed by up-regulation of downstream genes in the Wnt/β-catenin pathway in irradiated U87 cells. Importantly, inhibition of the Wnt/β-catenin pathway by XAV 939, which promotes degradation of β-catenin, significantly abrogated the pro-invasion effects of irradiation. Mechanistically, XAV 939 suppressed ionizing radiation-triggered up-regulation of MMP-2 and MMP-9, and inhibited the activities of these gelatinases.

CONCLUSION

Our data demonstrate a pivotal role of the Wnt/β-catenin pathway in ionizing radiation-induced invasion of glioblastoma cells, and suggest that targeting β-catenin is a promising therapeutic approach to overcoming glioma radioresistance.

Primary Macrophage Chemotaxis Induced by Cannabinoid Receptor 2 Agonists Occurs Independently of the CB2 Receptor

Activation of CB₂ has been demonstrated to induce directed immune cell migration. However, the ability of CB2 to act as a chemoattractant receptor in macrophages remains largely unexplored. Using a real-time chemotaxis assay and a panel of chemically diverse and widely used CB₂ agonists, we set out to examine whether CB₂ modulates primary murine macrophage chemotaxis. We report that of 12 agonists tested, only JWH133, HU308, L-759,656 and L-759,633 acted as macrophage chemoattractants. Surprisingly, neither pharmacological inhibition nor genetic ablation of CB₂ had any effect on CB₂ agonist-induced macrophage chemotaxis. As chemotaxis was pertussis toxin sensitive in both WT and CB₂^-/- macrophages, we concluded that a non-CB₁/CB₂, G_i/o-coupled GPCR must be responsible for CB₂ agonist-induced macrophage migration. The obvious candidate receptors GPR18 and GPR55 could not mediate JWH133 or HU308-induced cytoskeletal rearrangement or JWH133-induced β-arrestin recruitment in cells transfected with either receptor, demonstrating that neither are the unidentified GPCR. Taken together our results conclusively demonstrate that CB₂ is not a chemoattractant receptor for murine macrophages. Furthermore we show for the first time that JWH133, HU308, L-759,656 and L-759,633 have off-target effects of functional consequence in primary cells and we believe that our findings have wide ranging implications for the entire cannabinoid field.

Statins enhance rotator cuff healing by stimulating the COX2/PGE2/EP4 pathway: an in vivo and in vitro study

BACKGROUND

Statins are lipid-lowering drugs with many beneficial pleiotropic effects. Cyclooxygenase (COX2) selective inhibitors that are commonly prescribed in orthopaedic patients may effect healing. Evidence indicates that statins stimulate COX2 activity.

HYPOTHESIS

Atorvastatin (ATV) administration will enhance tendon healing by stimulating the acute inflammatory phase via increasing the production of prostaglandin E2 (PGE2).

STUDY DESIGN

Controlled laboratory study.

METHODS

After experimental rotator cuff (RC) tearing and suturing, 48 Wistar rats were randomly allocated into 4 groups: (1) ATV (20 mg/kg), (2) celecoxib (CEL; COX2 inhibitor) (10 mg/kg), (3) ATV + CEL (20 mg/kg + 10 mg/kg), and (4) saline alone. Animals were sacrificed 3 weeks after RC tears and repair, and tendon integrity was tested biomechanically in tension. To further evaluate the underlying mechanism of action, human and rat primary tenocytes were obtained from the supraspinatus tendon. Cultures were treated with a therapeutic dosage of 5 commonly used statins: CEL, ATV + CEL, PGE2, and a selective antagonist of PGE2 receptor 4 (EP4). Cell proliferation (thymidine incorporation), migration (wound healing assay), and adhesion (iCELLigence) were evaluated. The expression of all PGE2 receptors (EPs) was determined by quantitative reverse transcription polymerase chain reaction.

RESULTS

Tension testing of healed tendons demonstrated significantly higher maximal loading and stiffness in the ATV group as compared with the saline (+30% and +20%, respectively; P < .001) and CEL groups (+33% and +50%, respectively; P < .005). Celecoxib alone did not affect tendon healing (P = .88). In line with these in vivo results, tenocytes treated with statins demonstrated significantly higher proliferation rates; CEL abrogated this effect, and PGE2 treatment stimulated tenocyte proliferation even in the presence of CEL. Also, ATV stimulated the migration (wound healing) and adhesion of tenocytes. Among all PGE2 receptors, tenocytes mainly express EP4, and an EP4 selective antagonist blocked the effect of ATV.

CONCLUSION

Results indicate that ATV enhances tendon healing by stimulating tenocyte proliferation, migration, and adhesion via increased COX2 activity and autocrine/paracrine PGE2 signaling. Findings also demonstrate that this effect is mediated by EP4 signaling.

CLINICAL RELEVANCE

Although chronic inflammation contributes to the development of tendinopathy, study results advocate for a positive role of PGE2 in tendon healing during the acute inflammatory phase that follows tendon surgical repair. It is therefore suggested that ATV should be further investigated as a possible modality to improve tendon healing.

HIF-1α-independent hypoxia-induced rapid PTK6 stabilization is associated with increased motility and invasion

PTK6/Brk is a non-receptor tyrosine kinase overexpressed in cancer. Here we demonstrate that cytosolic PTK6 is rapidly and robustly induced in response to hypoxic conditions in a HIF-1-independent manner. Furthermore, a proportion of hypoxic PTK6 subsequently re-localized to the cell membrane. We observed that the rapid stabilization of PTK6 is associated with a decrease in PTK6 ubiquitylation and we have identified c-Cbl as a putative PTK6 E3 ligase in normoxia. The consequences of hypoxia-induced PTK6 stabilization and subcellular re-localization to the plasma membrane include increased cell motility and invasion, suggesting PTK6 targeting as a therapeutic approach to reduce hypoxia-regulated metastatic potential. This could have particular significance for breast cancer patients with triple negative disease.

Mangiferin has an additive effect on the apoptotic properties of hesperidin in Cyclopia sp. tea extracts

A variety of biological pro-health activities have been reported for mangiferin and hesperidin, two major phenolic compounds of Honeybush (Cyclopia sp.) tea extracts. Given their increasing popularity, there is a need for understanding the mechanisms underlying the biological effects of these compounds. In this study, we used real-time cytotoxicity cellular analysis of the Cyclopia sp. extracts on HeLa cells and found that the higher hesperidin content in non-fermented "green" extracts correlated with their higher cytotoxicity compared to the fermented extracts. We also found that mangiferin had a modulatory effect on the apoptotic effects of hesperidin. Quantitative PCR analysis of hesperidin-induced changes in apoptotic gene expression profile indicated that two death receptor pathway members, TRADD and TRAMP, were up regulated. The results of this study suggest that hesperidin mediates apoptosis in HeLa cells through extrinsic pathway for programmed cell death.