Ruthenium red-positive surface layer, extracellular filamentous material and intercellular junctions in hybrids between tumour and normal cells: abundant gap junctions correlate with density-dependent inhibition of growth

1978 ◽  
Vol 31 (1) ◽  
pp. 323-339
Author(s):  
S.C. Stamatoglou ◽  
C.J. Marshall
Keyword(s):  
Gap Junctions ◽  
Cell Lines ◽  
Intercellular Junctions ◽  
Cell Types ◽  
Parental Cell ◽  
Ruthenium Red ◽  
Hybrid Cells ◽  
Inhibition Of Growth ◽  
Dependent Inhibition ◽  
Transformed Cell Lines

The cell surface and intercellular junctions of transformed and non-transformed hybrid cells, obtained from fusion of murine mammary adenocarcinoma cells (TA3B) and normal rat embryofibroblasts (REF), were compared with those of the parental cells, using ruthenium red (RR) staining of cells fixed in situ. An RR-positive layer of variable thickness was found on the surface of all cell types. Measurements of the thickness of this layer on the free surface of the cell cultures deomonstrated a significant difference between transformed and non-transformed cells. The thickness distribution of the RR layer was similar on the surface of REF and non-transformed hybrid cells, but there was significant variation among all the transformed cell lines. Extracellular filamentous RR-positive material, usually in direct contact with the cell surface, was present in confluent cultures of REF and non-transformed hybrid cells, but was absent in the transformed cell lines. Gap junctions were few in both parental cell lines and rare or absent in transformed hybrids; a large increase in number and size of gap junctions was found in non-transformed hybrids. Abundance of long gap junctions was correlated with density-dependent inhibition of growth, since non-transformed hybrids grew in single layers whereas both normal and tumour parental cell types, and transformed hybrids grew in multilayers. Tight junctions were frequently encountered in TA3B and transformed hybrid cells but were not seen in REF cells and only occasionally seen in non-transformed hybrids. Intermediate-type junctions occurred in all cells, but desmosomes were found only rarely in TA3B cells and never in the other cell types.

Deficiency in intercellular communication in two established renal epithelial cell lines (LLC-PK1 and MDCK)

1984 ◽  
Vol 66 (1) ◽  
pp. 81-93
Author(s):  
F.V. Sepulveda ◽  
J.D. Pearson
Keyword(s):  
Epithelial Cell ◽  
Cell Lines ◽  
Mdck Cells ◽  
Cell Communication ◽  
Intercellular Junctions ◽  
Cell Types ◽  
Renal Epithelial Cell ◽  
Aortic Endothelial Cells ◽  
Epithelial Cell Lines ◽  
Autoradiographic Analysis

We have studied the cell-to-cell passage of uridine nucleotides in two renal epithelial cell lines (LLC-PK1 and MDCK) and in porcine aortic endothelial cells (PAE). All three cell types incorporated tritiated uridine. After a 3 h incubation the radioactivity was predominantly in the form of acid-soluble compounds, mainly UTP. Prelabelled LLC-PK1 or MDCK cells were unable to transfer radioactivity to added adjacent, non-labelled cells, whereas PAE cells readily formed communicating intercellular junctions, as judged by autoradiographic analysis after a 3 h co-culture period. Cell-to-cell communication in either of the renal cell lines was not promoted by treatment with dibutyryl cyclic AMP and methylisobutylxanthine. Radioactivity incorporated into the acid-insoluble pool was not available for intercellular transfer, as assessed in experiments in which cells were prelabelled 24 h before co-culture.

scholarly journals EvaluatingShigella flexneriPathogenesis in the Human Enteroid Model

2019 ◽  
Vol 87 (4) ◽  
Author(s):  
Sridevi Ranganathan ◽  
Michele Doucet ◽  
Christen L. Grassel ◽  
BreOnna Delaine-Elias ◽  
Nicholas C. Zachos ◽  
...  
Keyword(s):  
Animal Models ◽  
Cell Lines ◽  
System Modeling ◽  
Human Colon ◽  
Cell Types ◽  
Human Infection ◽  
Content Type ◽  
Transformed Cell ◽  
Severe Diarrhea ◽  
Transformed Cell Lines

ABSTRACTThe enteric pathogenShigellais one of the leading causes of moderate-to-severe diarrhea and death in young children in developing countries. Transformed cell lines and animal models have been widely used to studyShigellapathogenesis. In addition to altered physiology, transformed cell lines are composed of a single cell type that does not sufficiently represent the complex multicellular environment of the human colon. Most available animal models do not accurately mimic human disease. The human intestinal enteroid model, derived from LGR5+stem cell-containing intestinal crypts from healthy subjects, represents a technological leap in human gastrointestinal system modeling and provides a more physiologically relevant system that includes multiple cell types and features of the human intestine. We established the utility of this model for studying basic aspects ofShigellapathogenesis and host responses. In this study, we show thatShigellaflexneriis capable of infecting and replicating intracellularly in human enteroids derived from different segments of the intestine. Apical invasion byS. flexneriis very limited but increases ∼10-fold when enteroids are differentiated to include M cells. Invasion via the basolateral surface was at least 2-log10units more efficient than apical infection. Increased secretion of interleukin-8 and higher expression levels of the mucin glycoprotein Muc2 were observed in the enteroids followingS. flexneriinfection. The human enteroid model promises to bridge some of the gaps between traditional cell culture, animal models, and human infection.

scholarly journals Human Embryo Models and Drug Discovery

2021 ◽  
Vol 22 (2) ◽  
pp. 637
Author(s):  
Margit Rosner ◽  
Manuel Reithofer ◽  
Dieter Fink ◽  
Markus Hengstschläger
Keyword(s):  
Stem Cell ◽  
Drug Discovery ◽  
Cell Lines ◽  
Human Embryo ◽  
Cell Types ◽  
Human Cells ◽  
Disease Modelling ◽  
Specific Cell ◽  
Transformed Cell Lines

For obvious reasons, such as, e.g., ethical concerns or sample accessibility, model systems are of highest importance to study the underlying molecular mechanisms of human maladies with the aim to develop innovative and effective therapeutic strategies. Since many years, animal models and highly proliferative transformed cell lines are successfully used for disease modelling, drug discovery, target validation, and preclinical testing. Still, species-specific differences regarding genetics and physiology and the limited suitability of immortalized cell lines to draw conclusions on normal human cells or specific cell types, are undeniable shortcomings. The progress in human pluripotent stem cell research now allows the growth of a virtually limitless supply of normal and DNA-edited human cells, which can be differentiated into various specific cell types. However, cells in the human body never fulfill their functions in mono-lineage isolation and diseases always develop in complex multicellular ecosystems. The recent advances in stem cell-based 3D organoid technologies allow a more accurate in vitro recapitulation of human pathologies. Embryoids are a specific type of such multicellular structures that do not only mimic a single organ or tissue, but the entire human conceptus or at least relevant components of it. Here we briefly describe the currently existing in vitro human embryo models and discuss their putative future relevance for disease modelling and drug discovery.

Proenkephalin gene regulation in the neuroendocrine hypothalamus: a model of gene regulation in the CNS

1995 ◽  
Vol 269 (3) ◽  
pp. E393-E408 ◽  
Author(s):  
D. Borsook ◽  
S. E. Hyman
Keyword(s):  
Gene Regulation ◽  
Cell Lines ◽  
Second Messengers ◽  
Cell Types ◽  
Mobility Shift ◽  
Transformed Cell Lines ◽  
Electrophoretic Mobility Shift Assays ◽  
Made In

During the past decade, a great deal of progress has been made in studying the mechanisms by which transcription of neuropeptides is regulated by second messengers and neural activity. Such investigations, which have depended to a great extent on the use of transformed cell lines, are far from complete. Yet a major challenge for the coming decade is to understand the regulation of neuropeptide genes by physiologically and pharmacologically relevant stimuli in appropriate cell types in vivo. The proenkephalin gene, a member of the opioid gene family, has served as a model to study regulated transcription, not only in cell lines, but also in central (e.g., hypothalamic) and peripheral (e.g., adrenal) neuroendocrine tissues. Here we review regulation of proenkephalin gene expression in the hypothalamus. Several approaches, including in situ hybridization, use of transgenic mice, and the adaptation of electrophoretic mobility shift assays to complex tissues, have played critical roles in recent advances. A summary of possible future developments in this field of research is also presented.

Green Tea Polyphenol (−)-Epigallocatechin Gallate Inhibits IL-6 Mediated Signalling Pathways in Human Myeloma Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5049-5049
Author(s):  
Renate Burger ◽  
Hanna Czekalla ◽  
Kathrin Richter ◽  
Tanja Ahrens ◽  
Andreas Guenther ◽  
...  
Keyword(s):  
Cell Lines ◽  
Green Tea ◽  
Growth Factor Receptor ◽  
Epigallocatechin Gallate ◽  
Myeloma Cell ◽  
Lymphocytic Leukemia ◽  
Inhibition Of Growth ◽  
Stat3 Phosphorylation ◽  
Green Tea Polyphenol ◽  
Dependent Inhibition

Abstract Epigallocatechin-3-gallate (EGCG) is the predominant active ingredient of green tea leaves and has been shown to possess anti-tumor, anti-inflammatory, and anti-oxidant properties. EGCG confers its effects through potentially multiple mechanisms including inhibition of growth factor receptor signalling and decrease of cellular levels of anti-apoptotic proteins of the Bcl-2 family. We examined the effects of EGCG on a panel of human myeloma cell lines using EGCG concentrations ranging from 6.25–100 μM. After three days of culturing with EGCG, basal cell growth was inhibited in most of the cell lines as measured in an MTS based assay. IC50 concentrations were between 25 μM and 50 μM. IL-6 mediated growth of the IL-6 dependent INA-6 cell line was inhibited at similar doses. In these cells, stimulation with IL-6 leads to upregulation of Mcl-1 expression (Brocke-Heidrich et al., Blood.2004;103:242–251). Another green tea catechin, (−)-catechin gallate, seemed to be less active when used at identical concentrations. When INA-6 cells were pretreated for two hours with EGCG, a dose-dependent inhibition of IL-6 induced STAT3 tyrosine phosphorylation was observed as revealed by Western blot analysis. In contrast, phosphorylation of p44/p42 MAPK, which is constitutively activated in INA-6 cells, was not affected. The precise mechanism by which EGCG inhibits STAT3 phosphorylation remains to be determined. In conclusion, our results suggest to further evaluate the effect of EGCG not only in B-cell chronic lymphocytic leukemia, but also in plasma cell tumors.

scholarly journals Human adiponectin inhibits cell growth and induces apoptosis in human endometrial carcinoma cells, HEC-1-A and RL95–2

2007 ◽  
Vol 14 (3) ◽  
pp. 713-720 ◽  
Author(s):  
Li Cong ◽  
Jessica Gasser ◽  
Jessica Zhao ◽  
Baofeng Yang ◽  
Fanghong Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Endometrial Cancer ◽  
Cyclin D1 ◽  
Endometrial Carcinoma ◽  
Cell Lines ◽  
Prolonged Exposure ◽  
D1 Protein ◽  
Cell Types ◽  
Similar Treatment ◽  
Inhibition Of Growth

Obesity is one of the well-established risk factors for endometrial cancer. Recent clinical studies have demonstrated that circulating adiponectin concentrations are inversely correlated with the incidence of endometrial carcinoma. Such epidemiological findings are consistent with the paradoxical observations that adiponectin levels are reduced in obesity. This study investigated the direct effects of adiponectin on two endometrial carcinoma cell lines, HEC-1-A and RL95–2. These cell lines express both variants of adiponectin receptors, adipo-R1 and adipo-R2. Adiponectin treatment leads to suppression of cell proliferation in both cell types, which is primarily due to the significant increase of cell populations at G1/G0-phase and to the induction of apoptosis. The inhibition of growth in these two cell lines appears to be mediated by different signaling pathways. Although adiponectin treatment markedly increases the phosphorylation (Thr172) of AMP-activated protein kinase α in both HEC-1-A and RL95–2 within 30 min, prolonged exposure (48 h) leads to inactivation of Akt as well as reduction of cyclin D1 protein expression in HEC-1-A cells. In contrast, similar treatment of RL95–2 cells with adiponectin, while having no effects on Akt activity and cyclin D1 expression, causes a decrease in cyclin E2 expression and the activity of mitogen-activated kinase (p42/44). We conclude that adiponectin exerts direct anti-proliferative effects on HEC-1-A and RL95–2 cells by inducing cell cycle arrest and apoptosis. Depending on the genotypes of the endometrial cancer cells, the inhibitory effects of adiponectin are associated with the reduction of different pro-growth regulators of cell cycle and signaling proteins. Our study thus provides a cellular mechanism underlying the linkages between endometrial cancer and obesity.

scholarly journals A study of communication specificity between cells in culture.

1977 ◽  
Vol 75 (3) ◽  
pp. 769-787 ◽  
Author(s):  
M L Epstein ◽  
N B Gilula
Keyword(s):  
Gap Junctions ◽  
Cell Lines ◽  
Insect Cell ◽  
Cell Types ◽  
Cells In Culture ◽  
Culture Cells ◽  
Low Incidence ◽  
Insect Cell Lines ◽  
Gap Junctional ◽  
Ionic Coupling

We have examined the specificity of communication between cells in culture by co-culturing cells derived from mammalian, avian, and arthropod organisms. Both mammalian and avian culture cells have similar gap junctional phenotypes, while the insect (arthropod) cell lines have a significantly different gap junctional structure. Electrophysiological and ultrastructural methods were used to examine ionic coupling and junctional interactions between homologous and heterologous cell types. In homologous cell systems, gap junctions and ionic coupling are present at a high incidence. Also, heterologous vertebrate cells in co-culture can communicate readily. By contrast, practically no coupling (0-8%) is detectable between heterologous insect cell lines (Homopteran or Lepidopteran) and vertebrate cells (mammalian myocardial or 3T3 cells). No gap junctions have been observed between arthropod and vertebrate cell types, even though the heterologous cells may be separated by less than 10 nm. In additional studies, a low incidence of coupling was found between heterologous insect cell lines derived from different arthropod orders. However, extensive coupling was detected between insect cell lines that are derived from the same order (Homoptera). These observations suggest that there is little or no apparent specificity for communication between vertebrate cells in culture that express the same gap junctional phenotype, while there is a definite communication specificity that exists between arthropod cells in culture.

scholarly journals IN VITRO STUDIES ON THE SYNERGISTIC EFFECT OF MORINDA CITRIFOLIA L. (NONI) AND METHOTREXATE ON CYTOTOXICITY OF HELA CELL LINES

2019 ◽  
pp. 173-182
Author(s):  
MHATRE BHAKTI ◽  
MARAR THANKAMANI
Keyword(s):  
Hela Cell ◽  
Cell Lines ◽  
Dose Range ◽  
Cancer Cell Line ◽  
Inhibitory Effect ◽  
Morinda Citrifolia ◽  
Inhibition Of Growth ◽  
Hela Cell Lines ◽  
Dependent Inhibition

Objective: Cancer remains to be one of the leading causes of death around the world. Modern targeted therapies have undeniably improved cancer patients’ survival, but search still continues for safer and more effective drugs. This work is an attempt to assess the effectiveness of cotreatment of aqueous fruit extract of Morinda citrifolia L. (Noni) on methotrexate (MTX)-induced cytotoxicity on HeLa cancer cell line. Methods: HeLa cells were treated with different concentrations of MTX and Noni alone and in combination for 24 and 48 h and studied for the cytotoxic effects by various approaches. Results: There was a dose-dependent inhibition of growth when treated with MTX in a dose range of 0.045–45.4 μg/ml and Noni for a dose range of 0.3–30 mg/ml for 48 h. The IC50 for MTX was 4.45 μg/ml (1 μM/ml), and for Noni, it was 8 mg/ml while the combination exhibited a more intensive growth inhibitory effect. Our results were confirmed with phase-contrast microscopy, whereby the number of viable cells decreased with an increase in the concentration of Noni. Cells were found to have rounded up and detached from the flask indicating apoptosis. Apoptosis in HeLa cell lines was further confirmed by DNA fragmentation and flow cytometry. Conclusion: It can be concluded that Noni may enhance MTX cytotoxicity by inducing apoptosis and cell cycle arrest. Hence, cotreatment with Noni may reduce the dosage of MTX necessary for inhibiting proliferation of malignant cells and hence decrease the toxic effects of MTX on the system.

Quantitative EM of gap junction distribution in mutant drosophila wing discs

1983 ◽  
Vol 41 ◽  
pp. 720-721
Author(s):  
J.S. Ryerse
Keyword(s):  
Gap Junctions ◽  
Growth Control ◽  
Intercellular Junctions ◽  
Wing Disc ◽  
En Bloc ◽  
Metabolic Cooperation ◽  
Drosophila Wing ◽  
Adult Wing ◽  
Wing Discs ◽  
Wing Pouch

Gap junctions are intercellular junctions found in both vertebrates and invertebrates through which ions and small molecules can pass. Their distribution in tissues could be of critical importance for ionic coupling or metabolic cooperation between cells or for regulating the intracellular movement of growth control and pattern formation factors. Studies of the distribution of gap junctions in mutants which develop abnormally may shed light upon their role in normal development. I report here the distribution of gap junctions in the wing pouch of 3 Drosophila wing disc mutants, vg (vestigial) a cell death mutant, 1(2)gd (lethal giant disc) a pattern abnormality mutant and 1(2)gl (lethal giant larva) a neoplastic mutant and compare these with wildtype wing discs.The wing pouch (the anlagen of the adult wing blade) of a wild-type wing disc is shown in Fig. 1 and consists of columnar cells (Fig. 5) joined by gap junctions (Fig. 6). 14000x EMs of conventionally processed, UA en bloc stained, longitudinally sectioned wing pouches were enlarged to 45000x with a projector and tracings were made on which the lateral plasma membrane (LPM) and gap junctions were marked.

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