Search

An accurate and fast quantification of dissolved organic carbon (DOC) is essential for the characterization of the water quality in all kinds of water and for the evaluation of the efficiency of treatment processes. The conventional DOC determination method consists of on-site sampling and subsequent analysis in a stationary laboratory. However, this method is difficult to operate in cases where no or only poorly equipped laboratories are available in the vicinity of the sampling points. The objective of the present study is to investigate and to optimize a newly developed DOC determination method as a core element of a portable device. In addition, a first validation of a laboratory setup of this DOC analyzer is conducted. This analytical method is based on a miniaturized electrolysis decomposition cell equipped with a boron-doped diamond electrode (BDD). Within this study, the decomposition of different organic compounds (e. g. aromatic, aliphatic, and heterocyclic compounds) under galvanostatic conditions in an undivided electrolytic cell is systematically investigated. Experimental data, including studies on the influence of process and hydrochemical parameters, demonstrate the general suitability of the technical approach for practical on-site applications. The key features are: no need for extern ultra-pure gases, catalysts or burning technology, a low level of maintenance, and an analyzing time per sample below 7 min. [ABSTRACT FROM AUTHOR]

The biological phenomenon of cell fusion plays an important role in several physiological processes, like fertilization, placentation, or wound healing/tissue regeneration, as well as pathophysiological processes, such as cancer. Despite this fact, considerably less is still known about the factors and conditions that will induce the merging of two plasma membranes. Inflammation and proliferation has been suggested as a positive trigger for cell fusion, but it remains unclear, which of the factor(s) of the inflamed microenvironment are being involved. To clarify this we developed a reliable assay to quantify the in vitro fusion frequency of cells using a fluorescence double reporter vector (pFDR) containing a LoxP-flanked HcRed/DsRed expression cassette followed by an EGFP expression cassette. Because cell fusion has been implicated in cancer progression four human breast cancer cell lines were stably transfected with a pFDR vector and were co-cultured with the stably Cre-expressing human breast epithelial cell line. Cell fusion is associated with a Cre-mediated recombination resulting in induction of EGFP expression in hybrid cells, which can be quantified by flow cytometry. By testing a panel of different cytokines, chemokines, growth factors and other compounds, including exosomes, under normoxic and hypoxic conditions our data indicate that the proinflammatory cytokine TNF-α together with hypoxia is a strong inducer of cell fusion in human MDA-MB-435 and MDA-MB-231 breast cancer cells. [ABSTRACT FROM AUTHOR]

To develop adenoviral cell- or tissue-specific gene delivery, understanding of the infection mechanisms of adenoviruses is crucial. Several adenoviral attachment proteins such as CD46, CAR and sialic acid have been identified and studied. However, most receptor studies were performed on non-human cells. Combining our reporter gene-tagged adenovirus library with an in vitro human gene knockout model, we performed a systematic analysis of receptor usage comparing different adenoviruses side-by-side. The CRISPR/Cas9 system was used to knockout CD46 and CAR in the human lung epithelial carcinoma cell line A549. Knockout cells were infected with 22 luciferase-expressing adenoviruses derived from adenovirus species B, C, D and E. HAdV-B16, -B21 and -B50 from species B1 as well as HAdV-B34 and -B35 were found to be CD46-dependent. HAdV-C5 and HAdV-E4 from species E were found to be CAR-dependent. Regarding cell entry of HAdV-B3 and -B14 and all species D viruses, both CAR and CD46 play a role, and here, other receptors or attachment structures may also be important since transductions were reduced but not completely inhibited. The established human knockout cell model enables the identification of the most applicable adenovirus types for gene therapy and to further understand adenovirus infection biology. [ABSTRACT FROM AUTHOR]

Monocytes originate from precursors made in the bone and remain in the circulation for nearly 24 h. Much effort has been done to identify the molecules regulating transendothelial migration of monocytes during inflammatory conditions. In contrast, considerably less is known about the process of constitutive monocyte emigration although nearly 340 million monocytes leave the circulation each day in healthy individuals. Previous studies indicated that chemokines were up-regulated in monocytes cocultured with endothelial cells that induce the retraction of the latter cell type, thereby increasing vascular permeability. Thus, we hypothesized that the utilities required for efficient constitutive monocyte extravasation are generated by monocytes themselves because of adhesion to naïve endothelial cells. To test this hypothesis, cDNA microarray analysis was performed to determine the changes in the gene expression pattern of primary monocytes that have been attached to endothelial cells compared with monocytes that were held in suspension, and we were able to identify three major groups of genes. The first group includes genes such as matrix metalloproteinase 1, monocyte chemoattractant protein 1, and tissue transglutaminase 2. which are likely required for monocyte extravasation. The second group consists of genes that are expressed in phagocytes such as caveolin-1 and CD74. Finally, the third group comprises genes that are expressed in cells of endothelial tissue and cartilage including E-selectin, fibronectin-1, matrix Gla protein, and aggrecanase-2. In summary, we conclude that adhesion of peripheral blood monocytes to naïve endothelial cells has two effects: mandatory extravasation-specific genes are regulated, and the differentiation program of monocytes is initiated. [ABSTRACT FROM AUTHOR]

Background: In addition to physiological events such as fertilisation, placentation, osteoclastogenesis, or tissue regeneration/wound healing, cell fusion is involved in pathophysiological conditions such as cancer. Cell fusion, which applies to both the proteins and conditions that induce the merging of two or more cells, is not a fully understood process. Inflammation/pro-inflammatory cytokines might be a positive trigger for cell fusion. Using a Cre-LoxP-based cell fusion assay we demonstrated that the fusion between human M13SV1-Cre breast epithelial cells and human MDA-MB-435-pFDR1 cancer cells was induced by the pro-inflammatory cytokine tumour necrosis factor-α (TNF-α). Methods: The gene expression profile of the cells in the presence of TNF-α and under normoxic and hypoxic conditions was analysed by cDNA microarray analysis. cDNA microarray data were verified by qPCR, PCR, Western blot and zymography. Quantification of cell fusion events was determined by flow cytometry. Proteins of interest were either blocked or knocked-down using a specific inhibitor, siRNA or a blocking antibody. Results: The data showed an up-regulation of various genes, including claudin-1 (CLDN1), ICAM1, CCL2 and MMP9 in M13SV1-Cre and/or MDA-MB-435-pFDR1 cells. Inhibition of these proteins using a blocking ICAM1 antibody, CLDN1 siRNA or an MMP9 inhibitor showed that only the blockage of MMP9 was correlated with a decreased fusion rate of the cells. Likewise, the tetracycline-based antibiotic minocycline, which exhibits anti-inflammatory properties, was also effective in both inhibiting the TNF-α-induced MMP9 expression in M13SV1-Cre cells and blocking the TNF-α-induced fusion frequency of human M13SV1-Cre breast epithelial cells and human MDA-MB-435-pFDR1 cancer cells. Conclusions: The matrix metalloproteinase-9 (MMP9) is most likely involved in the TNF-α-mediated fusion of human M13SV1-Cre breast epithelial cells and human MDA-MB-435-pFDR1 cancer cells. Likewise, our data indicate that the tetracycline-based antibiotic minocycline might exhibit anti-fusogenic properties because it inhibits a cell fusion-related mechanism. [ABSTRACT FROM AUTHOR]

Cell fusion is a biological process that is crucial for the development and homeostasis of different tissues, but it is also pathophysiologically associated with tumor progression and malignancy. The investigation of cell fusion processes is difficult because there is no standardized marker. Many studies therefore use different systems to observe and quantify cell fusion in vitro and in vivo. The comparability of the results must be critically questioned, because both the experimental procedure and the assays differ between studies. The comparability of the fluorescence-based fluorescence double reporter (FDR) and dual split protein (DSP) assay was investigated as part of this study, in which general conditions were kept largely constant. In order to be able to induce both a high and a low cell fusion rate, M13SV1 breast epithelial cells were modified with regard to the expression level of the fusogenic protein Syncytin-1 and its receptor ASCT2 and were co-cultivated for 72 h with different breast cancer cell lines. A high number of fused cells was found in co-cultures with Syncytin-1-overexpressing M13SV1 cells, but differences between the assays were also observed. This shows that the quantification of cell fusion events in particular is highly dependent on the assay selected, but the influence of fusogenic proteins can be visualized very well.

The natural phenomenon of cell-cell fusion does not only take place in physiological processes, such as placentation, myogenesis, or osteoclastogenesis, but also in pathophysiological processes, such as cancer. More than a century ago postulated, today the hypothesis that the fusion of cancer cells with normal cells leads to the formation of cancer hybrid cells with altered properties is in scientific consensus. Some studies that have investigated the mechanisms and conditions for the fusion of cancer cells with other cells, as well as studies that have characterized the resulting cancer hybrid cells, are presented in this review. Hypoxia and the cytokine TNFα, for example, have been found to promote cell fusion. In addition, it has been found that both the protein Syncytin-1, which normally plays a role in placentation, and phosphatidylserine signaling on the cell membrane are involved in the fusion of cancer cells with other cells. In human cancer, cancer hybrid cells were detected not only in the primary tumor, but also in the circulation of patients as so-called circulating hybrid cells, where they often correlated with a worse outcome. Although some data are available, the questions of how and especially why cancer cells fuse with other cells are still not fully answered., (© 2024. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

ZEB1 plays a pivotal role in epithelial-to-mesenchymal transition (EMT), (cancer) cell stemness and cancer therapy resistance. The M13HS tumor hybrids, which were derived from spontaneous fusion events between the M13SV1-EGFP-Neo breast epithelial cells and HS578T-Hyg breast cancer cells, express ZEB1 and exhibit prospective cancer stem cell properties. To explore a possible correlation between the ZEB1 and stemness/ EMT-related properties in M13HS tumor hybrids, ZEB1 was knocked-out by CRISPR/Cas9. Colony formation, mammosphere formation, cell migration, invasion assays, flow cytometry and Western blot analyses were performed for the characterization of ZEB1 knock-out cells. The ZEB1 knock-out in M13HS tumor cells was not correlated with the down-regulation of the EMT-related markers N-CADHERIN (CDH2) and VIMENTIN and up-regulation of miR-200c-3p. Nonetheless, both the colony formation and mammosphere formation capacities of the M13HS ZEB1 knock-out cells were markedly reduced. Interestingly, the M13HS-2 ZEB1-KO cells harbored a markedly higher fraction of ALDH1-positive cells. The Transwell/ Boyden chamber migration assay data indicated a reduced migratory activity of the M13HS ZEB1-knock-out tumor hybrids, whereas in scratch/ wound-healing assays only the M13SH-8 ZEB1-knock-out cells possessed a reduced locomotory activity. Similarly, only the M13HS-8 ZEB1-knock-out tumor hybrids showed a reduced invasion capacity. Although the ZEB1 knock-out resulted in only moderate phenotypic changes, our data support the role of ZEB1 in EMT and stemness.

Cancer cell fusion represents a rare event. However, the surviving cancer hybrid cells after a post-hybrid selection process (PHSP) can overgrow other cancer cells by exhibiting a proliferation advantage and/or expression of cancer stem-like properties. Addition of new tumor properties during hetero-fusion of cancer cells e.g. with mesenchymal stroma-/stem-like cells (MSC) contribute to enhanced tumor plasticity via acquisition of new/altered functionalities. This provides new avenues for tumor development and metastatic behavior. Consequently, the present review article will also address the question as to whether cancer cell fusion represents a general and possibly evolutionary-conserved program or rather a random process?, (© 2023 the author(s), published by De Gruyter, Berlin/Boston.)

Cellular fusion e.g. between cancer cells and normal cells represents a stepwise process that is tightly regulated. During a pre-hybrid preparation program somatic cells and/or cancer cells are promoted to a pro-fusogenic state as a prerequisite to prepare a fusion process. A pro-fusogenic state requires significant changes including restructure of the cytoskeleton, e.g., by the formation of F-actin. Moreover, distinct plasma membrane lipids such as phosphatidylserine play an important role during cell fusion. In addition, the expression of distinct fusogenic factors such as syncytins and corresponding receptors are of fundamental importance to enable cellular mergers. Subsequent hybrid formation and fusion are followed by a post-hybrid selection process. Fusion among normal cells is important and often required during organismal development. Cancer cells fusion appears more rarely and is associated with the generation of new cancer hybrid cell populations. These cancer hybrid cells contribute to an elevated tumour plasticity by altered metastatic behaviour, changes in therapeutic and apoptotic responses, and even in the formation of cancer stem/ initiating cells. While many parts within this multi-step cascade are still poorly understood, this review article predominantly focusses on the intracellular necessities for fusion among cancer cells or with other cell populations of the tumour microenvironment. Video Abstract., (© 2023. The Author(s).)

Fusion among different cell populations represents a rare process that is mediated by both intrinsic and extracellular events. Cellular hybrid formation is relayed by orchestrating tightly regulated signaling pathways that can involve both normal and neoplastic cells. Certain important cell merger processes are often required during distinct organismal and tissue development, including placenta and skeletal muscle. In a neoplastic environment, however, cancer cell fusion can generate new cancer hybrid cells. Following survival during a subsequent post-hybrid selection process (PHSP), the new cancer hybrid cells express different tumorigenic properties. These can include elevated proliferative capacity, increased metastatic potential, resistance to certain therapeutic compounds, and formation of cancer stem-like cells, all of which characterize significantly enhanced tumor plasticity. However, many parts within this multi-step cascade are still poorly understood. Aside from intrinsic factors, cell fusion is particularly affected by extracellular conditions, including an inflammatory microenvironment, viruses, pH and ionic stress, hypoxia, and exosome signaling. Accordingly, the present review article will primarily highlight the influence of extracellular events that contribute to cell fusion in normal and tumorigenic tissues., Competing Interests: The authors declare no conflict of interest.

The aim of this study was to investigate the impact of cross-linked hyaluronic acid on osteoblast-like cells seeded on top of two collagen substrates, native porcine pericardium membrane (substrate A) and ribose cross-linked collagen membranes (substrate B), in an air-lift model. Substrates A or B, saturated with three hyaluronic acid concentrations, served as membranes for SAOS-2 cells seeded on top. Cultivation followed for 7 and 14 days in the air-lift model. Controls used the same substrates without hyaluronic pre-treatment. Cells were harvested, and four (Runx2, BGLAP, IBSP, Cx43) different osteogenic differentiation markers were assessed by qPCR. Triplicated experiment outcomes were statistically analyzed (ANOVA, t -test; SPSS). Supplementary histologic analysis confirmed the cells' vitality. After seven days, only few markers were overexpressed on both substrates. After 14 days, targeted genes were highly expressed on substrate A. The same substrate treated with 1:100 diluted xHyA disclosed statistically significant different expression level vs. substrate B ( p = 0.032). Time ( p = 0.0001), experimental condition as a function of time ( p = 0.022), and substrate ( p = 0.028) were statistically significant factors. Histological imaging demonstrated vitality and visualized nuclei. We conclude that the impact of hyaluronic acid resulted in a higher expression profile of SAOS-2 cells on substrate A compared to substrate B in an air-lift culture after two weeks.

Applying antibacterial coatings to dental implant materials seems reasonable but can have negative influences on desired cell adhesion and healing. In this study, zirconia abutment specimens interacting with gingival tissue were used. The aim was to compare the influence of machined or coated zirconia surfaces on the adhesion and proliferation of human gingival fibroblasts (HGF-1). Surface modifications were performed using atmospheric plasma coating with hydroxyapatite, zinc, and copper. Zirconia specimens were divided into four groups: hydroxyapatite, hydroxyapatite with zinc oxide (ZnO), hydroxyapatite with copper (Cu), and an untreated machined surface. After the characterization of the surface conditions, the morphology of adhered HGF-1 was determined by fluorescence staining and subjected to statistical evaluation. The visual analysis of cell morphology by SEM showed flat, polygonal, and largely adherent fibroblast cells in the untreated group, while round to partially flat cells were recorded in the groups with hydroxyapatite, hydroxyapatite + ZnO, and hydroxyapatite + Cu. The cell membranes in the hydroxyapatite + ZnO and hydroxyapatite + Cu groups appeared porous. The results show that HGF-1 adhere and proliferate well on machined zirconia, while plasma coating with hydroxyapatite or hydroxyapatite mixtures does not lead to increased adhesion or proliferation.

CS/ICs have raised great expectations in cancer research and therapy, as eradication of this key cancer cell type is expected to lead to a complete cure. Unfortunately, the biology of CS/ICs is rather complex, since no common CS/IC marker has yet been identified. Certain surface markers or ALDH1 expression can be used for detection, but some studies indicated that cancer cells exhibit a certain plasticity, so CS/ICs can also arise from non-CS/ICs. Another problem is intratumoral heterogeneity, from which it can be inferred that different CS/IC subclones must be present in the tumor. Cell-cell fusion between cancer cells and normal cells, such as macrophages and stem cells, has been associated with the generation of tumor hybrids that can exhibit novel properties, such as an enhanced metastatic capacity and even CS/IC properties. Moreover, cell-cell fusion is a complex process in which parental chromosomes are mixed and randomly distributed among daughter cells, resulting in multiple, unique tumor hybrids. These, if they have CS/IC properties, may contribute to the heterogeneity of the CS/IC pool. In this review, we will discuss whether cell-cell fusion could also lead to the origin of different CS/ICs that may expand the overall CS/IC pool in a primary tumor.

Cell fusion is a well-known, but still scarcely understood biological phenomenon, which might play a role in cancer initiation, progression and formation of metastases. Although the merging of two (cancer) cells appears simple, the entire process is highly complex, energy-dependent and tightly regulated. Among cell fusion-inducing and -regulating factors, so-called fusogens have been identified as a specific type of proteins that are indispensable for overcoming fusion-associated energetic barriers and final merging of plasma membranes. About 8% of the human genome is of retroviral origin and some well-known fusogens, such as syncytin-1, are expressed by human (cancer) cells. Likewise, enveloped viruses can enable and facilitate cell fusion due to evolutionarily optimized fusogens, and are also capable to induce bi- and multinucleation underlining their fusion capacity. Moreover, multinucleated giant cancer cells have been found in tumors derived from oncogenic viruses. Accordingly, a potential correlation between viruses and fusogens of human endogenous retroviral origin in cancer cell fusion will be summarized in this review.

Regenerative medicine is concerned with the investigation of therapeutic agents that can be used to promote the process of regeneration after injury or in different diseases. Mesenchymal stem/stromal cells (MSCs) and their secretome-including extracellular vesicles (EVs) are of great interest, due to their role in tissue regeneration, immunomodulatory capacity and low immunogenicity. So far, clinical studies are not very conclusive as they show conflicting efficacies regarding the use of MSCs. An additional process possibly involved in regeneration might be cell fusion. This process occurs in both a physiological and a pathophysiological context and can be affected by immune response due to inflammation. In this review the role of MSCs and cell fusion in tissue regeneration is discussed.

Fusion of cancer cells either with other cancer cells (homotypic fusion) in local vicinity of the tumor tissue or with other cell types (e.g., macrophages, cancer-associated fibroblasts (CAFs), mesenchymal stromal-/stem-like cells (MSC)) (heterotypic fusion) represents a rare event. Accordingly, the clinical relevance of cancer-cell fusion events appears questionable. However, enhanced tumor growth and/or development of certain metastases can originate from cancer-cell fusion. Formation of hybrid cells after cancer-cell fusion requires a post-hybrid selection process (PHSP) to cope with genomic instability of the parental nuclei and reorganize survival and metabolic functionality. The present review dissects mechanisms that contribute to a PHSP and resulting functional alterations of the cancer hybrids. Based upon new properties of cancer hybrid cells, the arising clinical consequences of the subsequent tumor heterogeneity after cancer-cell fusion represent a major therapeutic challenge. However, cellular partners during cancer-cell fusion such as MSC within the tumor microenvironment or MSC-derived exosomes may provide a suitable vehicle to specifically address and deliver anti-tumor cargo to cancer cells.

Background: Phosphotyrosine kinase (PTK)-mediated phospholipase C-γ1 (PLC-γ1) signaling plays a crucial role in the release of the universal second messenger calcium from intracellular stores, which is mandatory for several cellular processes, including cell migration. However, PLC-γ1 could also be activated in a PTK-independent manner by phospholipase D (PLD)-derived phosphatidic acid (PA). Because both higher PLD expression levels and PLD activity have also been associated with breast cancer cell invasion and migration, we wondered whether there might be a link between PLD and PLC-γ1, which was investigated in this study., Materials: MDA-MB-468-NEO (EGFR positive) and MDA-MB-468-HER2 (EGFR and HER2 positive) human breast cancer cells were used in this study. The migratory behavior of the cells in the presence of epidermal growth factor (EGF) and the PLD inhibitor 5-fluoro-2-indolyl-des-chlorohalopemide (FIPI) was analyzed using the 3D collagen matrix migration assay. Changes in cytosolic calcium levels in the presence of EGF, FIPI and Sig-1R agonists and antagonists as well as in PLD1 siRNA knockdown cells were determined by flow cytometry. Western blot analyses were performed to determine the basal expression levels and phosphorylation patterns of EGFR, HER2, AKT, MAPK p42/44 , PLC-γ1 and Sig-1R., Results: The EGF-induced migration of MDA-MB-468-NEO and MDA-MB-468-HER2 cells was significantly impaired by FIPI. Likewise, FIPI also significantly abolished EGF-induced calcium release in both cell lines. However, neither the expression levels nor the phosphorylation patterns of EGFR, HER2, AKT, MAPK p42/44 and PLC-γ1 were markedly changed by FIPI. Knockdown of PLD1 expression by siRNA also significantly impaired EGF-induced calcium release in both cell lines. Targeting Sig-1R, which interacts with IP3R, with the antagonist BD1047 also abrogated EGF-induced calcium release. However, EGF-induced calcium release was also impaired if cells were treated with the Sig-1R agonists PRE084 and PPBP maleate., Conclusion: In summary, blocking PLD activity with the specific inhibitor FIPI or knocking down PDL1 expression by siRNA significantly impaired EGF-induced calcium release in MDA-MB-468-NEO and MDA-MB-468-HER2 cells, likely indicating a connection between PLD activity and PLC-γ1-mediated calcium signaling. However, how PLD activity interferes with the release of calcium from intracellular stores remains unclear. Video Abstract.

Background: Several physiological (fertilization, placentation, wound healing) and pathophysiological processes (infection with enveloped viruses, cancer) depend on cell fusion. In cancer it was postulated that the fusion of cancer cells with normal cells such as macrophages or stem cells may not only give rise to hybrid cells exhibiting novel properties, such as an increased metastatic capacity and drug resistance, but possibly also cancer stem/ initiating cell properties. Hence, hybrid clone cells (M13HS, M13MDA435 and M13MDA231) that were derived from spontaneous fusion events of human M13SV1-EGFP-Neo breast epithelial cells and HS578T-Hyg, MDA-MB-435-Hyg and MDA-MB-231-Hyg cancer cells were investigated regarding potential in vitro cancer stem/ initiating cell properties., Methods: CD44/CD24 expression pattern and ALDH1 activity of parental cells and hybrid clones was determined by flow cytometry. A colony formation and mammosphere formation assay was applied to determine the cells' capability to form colonies and mammospheres. Sox9, Slug and Snail expression levels were determined by Western blot analysis., Results: Flow cytometry revealed that all hybrid clone cells were CD44 + /CD24 -/low , but differed markedly among each other regarding ALDH1 activity. Likewise, each hybrid clone possessed a unique colony formation and mammosphere capacity as well as unique Snail, Slug and Sox9 expression patterns. Nonetheless, comparison of hybrid clones revealed that M13HS hybrids exhibited more in vitro cancer stem/ initiating cell properties than M13MDA231 and M13MDA435 hybrids, such as more ALDH1 positive cells or an increased capacity to form colonies and mammospheres., Conclusion: The fate whether cancer stem/ initiating cells may originate from cell fusion events likely depends on the specific characteristics of the parental cells.

Background: To date, several studies have confirmed that driving forces of the inflammatory tumour microenvironment trigger spontaneous cancer cell fusion. However, less is known about the underlying factors and mechanisms that facilitate inflammation-induced cell fusion of a cancer cell with a normal cell. Recently, we demonstrated that minocycline, a tetracycline antibiotic, successfully inhibited the TNF-α-induced fusion of MDA-MB-435 cancer cells with M13SV1 breast epithelial cells. Here, we investigated how minocycline interferes with the TNF-α induced signal transduction pathway., Methods: A Cre-LoxP recombination system was used to quantify the fusion of MDA-MB-435-pFDR1 cancer cells and M13SV1-Cre breast epithelial cells. The impact of minocycline on the TNF-α signalling pathway was determined by western blotting. The transcriptional activity of NF-κB was characterised by immunocytochemistry, western blot and ChIP analyses. An NF-κB-luciferase reporter assay was indicative of NF-κB activity., Results: Minocycline treatment successfully inhibited the TNFR1-TRAF2 interaction in both cell types, while minocycline abrogated the phosphorylation of IκBα and NF-κB-p65 to suppress nuclear NF-κB and its promotor activity only in M13SV1-Cre cells, which attenuated the expression of MMP9 and ICAM1. In MDA-MB-435-pFDR1 cells, minocycline increased the activity of NF-κB, leading to greater nuclear accumulation of NF-κB-p65, thus increasing promoter activity to stimulate the expression of ICAM1. Even though TNF-α also activated all MAPKs (ERK1/2, p38 and JNK), minocycline differentially affected these kinases to either inhibit or stimulate their activation. Moreover, SRC activation was analysed as an upstream activator of MAPKs, but no activation by TNF-α was revealed. The addition of several specific inhibitors that block the activation of SRC, MAPKs, AP-1 and NF-κB confirmed that only NF-κB inhibition was successful in inhibiting the TNF-α-induced cell fusion process., Conclusion: Minocycline is a potent inhibitor in the TNF-α-induced cell fusion process by targeting the NF-κB pathway. Thus, minocycline prevented NF-κB activation and nuclear translocation to abolish the target-gene expression of MMP9 and ICAM1 in M13SV1-Cre cells, resulting in reduced cell fusion frequency.

There is a growing list of data indicating that cancer (stem) cells could functionally adapt foreign tissue features, such as endothelial-like cells or neuroendocrine cells, express lineage markers or could differentiate into various lineages in response to appropriate differentiation criteria. The finding that cancer (stem) cells may possess some kind of differentiation capacity poses the question whether this might be an inherent or acquired property. Cancer stem cells share stem cell characteristics and may thus possess an inherent differentiation capacity enabling the cells to respond to various differentiation stimuli. Considering the plasticity of cancer (stem) cells, even non-tumorigenic (and putatively non-differentiable) tumor cells could give rise to tumorigenic tumor stem cells, exhibiting stem cell characteristics including an inherent differentiation capacity. On the contrary, cancer (stem) cells may have acquired differentiation capacity as a consequence of a previous cell fusion event with cell types exhibiting differentiation potential and being fusogenic, such as macrophages or stem cells. Of pivotal interest in a tumor context are macrophages, which chiefly foster the chronically inflamed tumor microenvironment. Because chronically inflamed tissue is a well-known trigger for cell fusion and both macrophages and stem cells are highly fusogenic we conclude that cell fusion events between these cell types and cancer (stem) cells should frequently occur, thereby giving rise to hybrid cells exhibiting not only novel properties, like an enhanced metastatogenic phenotype, but also parental characteristics, such as differentiation capacity. Conceivably, the combination of both properties might be advantageous for metastasizing cancer (stem) cells to adapt better and faster to a foreign organ tissue environment., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

At a progressive rate, small wastewater treatment plants in rural areas need to be equipped with an additional phosphorus removal stage in order to achieve a good chemical status in the receiving natural water bodies. A conventional regeneration method for ferric (hydr)oxides such as phosphate specific adsorbents, which can be applied to remove and recover phosphorus in fixed bed filters, was investigated and improved. It was shown that a loss of up to 85% of the initial capacity can be observed when regeneration with 1 M NaOH is implemented. The losses are caused by surface blocking with different calcium-containing compounds as revealed by an EDX analysis. These blocking compounds could be removed completely with an additional acidic regeneration step at pH = 2.5. During the alkaline desorption that followed, complete phosphorus removal and a full recovery of the adsorption capacity were achieved for goethite-rich Bayoxide(®) E 33 HC (E33HC) and akaganéite-rich GEH(®) 104 (GEH). The regeneration procedure was repeated up to eight times without any signs of further decline in the phosphate adsorption capacity or any changes in the specific surface area or pore size distribution of the adsorbent. In contrast to GEH and E33HC, ferric hydroxide- and calcite-rich FerroSorp(®) Plus (FSP) was partly dissolved during acid treatment., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Aneuploidy, metastasis formation, and drug resistance are major issues to overcome in most cancers. If there exists common underlying proceedings for the formation of these phenomena is still unknown. The searching and thereby better understanding of causal mechanisms could promote the generation of drugs targeting the ultimate cause of these cancer promoting events. The merging of a cancer cell with another cancer cell or normal cell could be one explanation how cancer cells could gain advantageous properties and escape eliminating cell fates thereby foster cancer progression. This chapter summarizes how cell-cell fusion could directly be involved in the pathogenesis of cancer and which often cancer associated mechanisms, like viral infections or chronic inflammation, are hitherto proposed to trigger cell fusion in cancer context.

Reuse of wastewater contributes significantly to an efficient and sustainable water usage. However, due to the presence of a multitude of pathogens (e.g. bacteria, viruses, worms, protozoa) in secondary effluents, disinfection procedures are indispensable. In decentralized wastewater treatment, UV irradiation represents one of the most common disinfection methods in addition to membrane processes and to a certain extent electrochemical procedures. However, the usage of UV disinfected secondary effluents for domestic (sanitary) or irrigation purposes bears a potential health risk due to the possible photo and dark repair of reversibly damaged bacteria. Against this background, the application of the UV/electrolysis hybrid technology for disinfection and prevention of bacterial reactivation in biologically treated wastewater was investigated in view of relevant influence factors and operating limits. Furthermore, the influence of electrochemically generated total oxidants on the formation of biofilms on quartz glass surfaces was examined, since its preventive avoidance contributes to an enhanced operational safety of the hybrid reactor. It was found that reactivation of bacteria in UV irradiated, biologically treated wastewater can be prevented by electrochemically produced total oxidants. In this regard, the influence of the initial concentration of the microbiological indicator organism Escherichia coli (E. coli) (9.3*10(2)-2.2*10(5) per 100 mL) and the influence of total suspended solids (TSS) in the range of 11-75 mg L(-1) was examined. The concentration of total oxidants necessary for prevention of bacterial regrowth increases linearly with the initial E. coli and TSS concentration. At an initial concentration of 933 E. coli per 100 mL, a total oxidants concentration of 0.4 mg L(-1) is necessary to avoid photo reactivation (at 4200 Lux), whereas 0.67 mg L(-1) is required if the E. coli concentration is enhanced by 2.4 log levels (cTSS = constant = 13 mg L(-1)). The prevention of dark repair is ensured with 25-50% lower concentration of total oxidants. An increase of the TSS concentration from 11 mg L(-1) to 75 mg L(-1) leads to a triplication of the need of total oxidants from 0.6 mg L(-1) to 1.8 mg L(-1) (3*10(5)E. coli per 100 mL). The energy consumption of the hybrid reactor varies from 0.17 kWh m(-3) to 0.94 kWh m(-3) depending on the TSS concentration (11-75 mg L(-1)). Furthermore, biofilm formation on quartz glass surfaces, of which the sleeves of UV lamps consist, can be suppressed by electrochemically produced total oxidants at a concentration of at least 1 mg L(-1) which ensures high operational safety of the hybrid reactor combined with large maintenance intervals., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Mesenchymal stem cells raise great expectations in regenerative medicine due to their capacity to regenerate damaged tissues, thereby restoring organ tissue integrity and functionality. Even though it is not yet clear how mesenchymal stem cells are guided to injured tissue it is generally assumed that the directed migration of these cells is facilitated by the same soluble factors that also recruit immune competent cells to inflamed tissue areas. Tumor tissue represents another type of (chronically) inflamed tissue and because of that mesenchymal stem cells are highly attracted. Although some data indicate that esenchymal stem cells might have a beneficial effect on tumor growth due to anti-tumor effects the plethora of data suggest that tumor tissue recruited mesenchymal stem cells rather promote tumor growth and metastasis formation. Nonetheless, the enhanced tumor tropism of mesenchymal stem cells makes them ideal candidates for novel anti-cancer strategies. Like Trojan Horses genetically modified mesenchymal stem cells will deliver their deadly cargo, such as anti-tumor cytokines or oncolytic viruses, into cancerous tissues, thereby destroying the tumor form within. In this chapter we will summarize the current concepts of genetic modification of mesenchymal stem cells for future anti-cancer therapies.

Although cell fusion is an omnipresent process in life, to date considerably less is still known about the mechanisms and the molecules being involved in this biological phenomenon in higher organisms. In Cell Fusion in Health and Disease Volume 1 international leading experts will present up-to-date overviews about the current knowledge about cell fusion-mediating molecules in C. elegans and mammalian cells. Further topics of the book will focus on cell fusion in physiological processes including fertilization, placentation, skeletal muscle development, and tissue repair and will sum up the use of artificial cell fusion for cellular reprogramming and cancer vaccine development. Thus, Cell Fusion in Health and Disease Volume 1 represents a state-of-the-art work for researchers, physicians or professionals being interested in the biological phenomenon of cell fusion in physiological processes and beyond.

Although cell fusion is an omnipresent process in life, to date considerably less is still known about the mechanisms and the molecules being involved in this biological phenomenon in higher organisms. Cell Fusion in Health and Disease Volume 2 is covering the dark side of cell fusion: namely its role in pathophysiological processes. International leading experts will present up-to-date overviews about cell fusion mediated horizontal gene transfer in bacteria and viruses, class III viral membrane fusion proteins, trophoblast fusion in trisomy 21, and the role of microvesicles in malignancies. Particular attention is paid on cell fusion in cancer and how this biological phenomenon may initiate the origin of (recurrence) cancer stem cells as well as drive the progression of multiple myeloma, colon cancer, breast cancer, and malignant melanoma. Thus, Cell Fusion in Health and Disease Volume 2 represents a state-of-the-art work for researchers, physicians or professionals being interested in reflecting the dark side of cell fusion.

Cancer stem cells (CSCs) are a rare population of cancer cells exhibiting stem cell properties, such as self-renewal, differentiation and tissue restoration. Beside the initiation of the primary tumor, CSCs have also been associated with metastasis formation and cancer relapses. In the context of cancer relapses, we have recently postulated the existence of so-called recurrence CSCs (rCSCs). These specific CSC subtype will initiate relapses exhibiting an "oncogenic resistance" phenotype, which are characterized by a markedly increased malignancy concomitant with a drug resistance towards first line therapy. In the present chapter we will discuss the necessity of rCSCs as a distinct CSC subtype and that cell fusion could be one mechanism how rCSCs could originate.

The aim of this study has been to characterize adult human somatic periodontium-derived stem cells (PDSCS) isolated from human periodontium and to follow their differentiation after cell culture. PDSCS were isolated from human periodontal tissue and cultured as spheres in serum-free medium. After 10 days the primary spheres were dissociated and the secondary spheres sub-cultured for another 1-2 weeks. Cells from different time points were analyzed, and immunohistochemical and electron microscopic investigations carried out. Histological analysis showed differentiation of spheres deriving from the PDSCS with central production of extracellular matrix beginning 3 days after sub-culturing. Isolated PDSCS developed pseudopodia which contained actin. Tubulin was found in the central portion of the cells. Pseudopodia between different cells anastomosed, indicating intercellular transport. Immunostaining for osteopontin demonstrated a positive reaction in primary spheres and within extracellular matrix vesicles after sub-culturing. In cell culture under serum-free conditions human PDSCS form spheres which are capable of producing extracellular matrix. Further investigations have do be carried out to investigate the capability of these cells to differentiate into osteogenic progenitor cells., (2010 Elsevier GmbH. All rights reserved.)

The ability of hematopoietic stem and progenitor cells (HSPCs) to migrate is a prerequisite for bone marrow homing and tissue regeneration processes. Induction of HSPC migration is chiefly directed by stromal cell-derived factor-1alpha (SDF-1alpha). Considerably less is known about factors that terminate HSPC migration. Adult CD133(+) HSPCs were isolated from mobilized peripheral blood by immunomagnetic separation. Cell migration was assessed using the three-dimensional collagen matrix migration assay, which allows detailed migration analysis on a cell population and single-cell level. The SDF-1alpha-induced locomotory activity of CD133(+) cells was efficiently blocked by the neurotransmitter gamma-aminobutyric acid (GABA). GABA signaling was effected via the GABA(B)-receptor. This was verified by flow cytometry and cell migration studies using the specific GABA(A)-receptor and GABA(B)-receptor agonists isoguvacine and baclofen, respectively. Baclofen blocked SDF-1alpha-induced migration of CD133(+) cells. Flow cytometry-based calcium measurements revealed that GABA inhibits the SDF-1alpha-induced migration of CD133(+) cells by blocking the SDF-1alpha-induced calcium influx. Similar results were obtained with the specific calcium-release-activated calcium (CRAC) channel inhibitor BTP-2, which both blocked the SDF-1alpha-induced calcium influx and migration of CD133(+) cells. These results suggest that GABA(B)-receptor signaling modulates the activity of CRAC channels, whereby the mechanism in detail remains unclear. In summary, the neurotransmitter GABA is a potent blocker of the SDF-1alpha-induced migration of CD133(+) HSPCs from mobilized peripheral blood.