scholarly journals Cytochemical study of concanavalin A binding sites and their mobility in normal, cystic fibrosis, and SV40 transformed human fibroblasts in vitro.

1980 ◽  
Vol 28 (6) ◽  
pp. 543-551 ◽  
Author(s):  
M Yokoyama ◽  
J P Chang ◽  
P C Moller
Keyword(s):  
Concanavalin A ◽  
Binding Sites ◽  
Plasma Membranes ◽  
Human Fibroblasts ◽  
Transformed Cells ◽  
Reaction Products ◽  
Con A ◽  
Normal Cells ◽  
Cytochemical Study

Concanavalin A (Con A) binding sites and their mobility were studied by peroxidase (Po) and ferritin labeling techniques in normal and SV40 transformed human fibroblasts. Binding sites were visualized either as osmium black of 3'3-diaminobenzidine (DAB) reactions or as ferritin particles. DAB reaction products were localized at the external surface of the plasma membrane and in some multivesicular bodies of fixed cells. The labeling was continuous in normal and SV40 transformed human fibroblasts. When living cells were treated with Con A-Po at 4 degrees C and incubated at 37 degrees C, both normal and transformed cells showed remarkable changes. The foci of membrane indentations (caps or patches) are formed on the cell surface. Many labeled internalized vacuoles and vesicles appeared within the cytoplasm and in close proximity to the Golgi region of all cell types. The cellular changes occurred more quickly in transformed cells than in normal cells. It is concluded that normal cells do cap under certain conditions and that the plasma membranes of transformed cells are more fluid than those of normal cells.

scholarly journals Antagonism by dibutyryl adenosine cyclic 3',5'-monophosphate and testololactone of concanavalin A capping.

1975 ◽  
Vol 66 (2) ◽  
pp. 392-403 ◽  
Author(s):  
B Storrie
Keyword(s):  
Concanavalin A ◽  
Binding Sites ◽  
Cytochalasin B ◽  
Cold Treatment ◽  
Intracellular Camp ◽  
Camp Concentration ◽  
Con A ◽  
Cell Rounding ◽  
Intracellular Camp Concentration

Exposure of CHO-K1 cells in vitro to dibutyryl adenosine cyclic 3',5'-monophosphate (DBcAMP) plus testololactone produces a rapid, reversible antagonism of ligand-induced collection of initially dispersed concanavalin A (Con A) binding sites into a caplike mass. Morphologically, as Con A capping occurs, the cells become less spread and then round completely. With prolonged Con A exposure, cells cultured in either the absence or the presence of DBcAMP plus testololactone cap and round. Capping is blocked by cold treatment and respiratory inhibitors. Colcemid at concentrations greater than 1 muM promotes both Con A capping and cell rounding. Cytochalasin B at similar concentrations inhibits both capping and cell rounding. Treatment of cells with Con A has little effect on intracellular cAMP concentration. Possible mechanisms by which cAMP may modulate the movement of Con A binding sites are discussed.

High and low affinity binding sites for Concanavalin A on normal human fibroblasts in vitro

1977 ◽  
Vol 76 (4) ◽  
pp. 1027-1035 ◽  
Author(s):  
Martha Feller ◽  
Charles Richardson ◽  
W. David Behnke ◽  
Eric Gruenstein
Keyword(s):  
Concanavalin A ◽  
Binding Sites ◽  
Human Fibroblasts ◽  
Affinity Binding ◽  
Normal Human

scholarly journals EFFECTS OF COLCHICINE, CYTOCHALASIN B, AND 2-DEOXYGLUCOSE ON THE TOPOGRAPHICAL ORGANIZATION OF SURFACE-BOUND CONCANAVALIN A IN NORMAL AND TRANSFORMED FIBROBLASTS

1974 ◽  
Vol 61 (1) ◽  
pp. 70-82 ◽  
Author(s):  
Thomas E. Ukena ◽  
Joan Z. Borysenko ◽  
Morris J. Karnovsky ◽  
Richard D. Berlin
Keyword(s):  
Binding Site ◽  
Concanavalin A ◽  
Binding Sites ◽  
Cytochalasin B ◽  
Simian Virus 40 ◽  
Colchicine Treatment ◽  
Simian Virus ◽  
Transformed Cells ◽  
Con A ◽  
Primary Organization

The distribution of surface-bound concanavalin A on the membranes of 3T3, and simian virus 40-transformed 3T3 cultured mouse fibroblasts was examined using a shadow-cast replica technique with a hemocyanin marker. When cells were prefixed in paraformaldehyde, the binding site distribution was always random on both cell types. On the other hand, labeling of transformed cells with concanavalin A (Con A) and hemocyanin at 37°C resulted in the organization of Con A binding sites (CABS) into clusters (primary organization) which were not present on the pseudopodia and other peripheral areas of the membrane (secondary organization). Treatment of transformed cells with colchicine, cytochalasin B, or 2-deoxyglucose did not alter the inherent random distribution of binding sites as determined by fixation before labeling. However, these drugs produced marked changes in the secondary (but not the primary) organization of CABS on transformed cells labeled at 37°C. Colchicine treatment resulted in the formation of a caplike aggregation of binding site clusters near the center of the cell, whereas cytochalasin B and 2-deoxyglucose led to the formation of patches of CABS over the entire membrane, eliminating the inward displacement of patches observed on untreated cells. The distribution of bound Con A on normal cells (3T3) at 37°C was always random, in both control and drug-treated preparations. Pretreatment of cells with Con A enhanced the effect of colchicine on cell morphology, but inhibited the morphological effects of cytochalasin B. The mechanisms that determine receptor movement and disposition are discussed.

Characterization of an SV40-transformed 3T3 cell line expressing an unusual phenotype

1975 ◽  
Vol 18 (3) ◽  
pp. 427-440
Author(s):  
J.E. Thompson ◽  
J.D. Elligsen ◽  
H.E. Frey
Keyword(s):  
Plasma Membranes ◽  
Polyacrylamide Gel Electrophoresis ◽  
Growth Control ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Transformed Cells ◽  
Con A ◽  
Normal Cells ◽  
Unusual Phenotype

A transformed variant derived as a clone from normal 3T3 cells infected with simian virus 40 (SV40) has been found to possess a phenotype intermediate between that of normal cells and that characteristic of the transformed state, yet cells of the variant still test positively for the SV40-specific nuclear T-antigen. The variant exercises growth control, although not as stringently as do normal cells. Its cell size more closely resembles that of normal cells than of transformed cells. The variant also exhibits levels of spontaneous agglutination that are in line with those characteristic of the normal cells from which it was derived, and far higher than corresponding values for cells exhibiting the fully transformed phenotype. Plasma membranes of variant cells more closely resemble those of transformed cells than of normal cells as estimated by polyacrylamide gel electrophoresis. Perhaps the most distinguishing characteristic of the transformed variant is its complete immunity to agglutination by concanavalin A (Con A), even at concentrations of the lectin as high as 500 mug/ml. Moreover, trypsinization does not render variant cells as agglutinable in the presence of Con A as are untreated fully transformed cells. By contrast the variant displays a low tolerance of Con A toxicity, as monitored by ability to grow after treatment with the lectin, and on this count resembles transformed cells. Moreover a survey of several normal cell lines has revealed that even they do not consistently show resistance to Con A toxicity. These observations indicate that Con A-mediated agglutination and inability to grow after treatment with Con A are quite independent and do not bear a cause and effect relationship.

scholarly journals Fluorescent antibodies and lectins stain intracellular structures in fixed cells treated with nonionic detergent.

1978 ◽  
Vol 26 (4) ◽  
pp. 251-257 ◽  
Author(s):  
P Laurila ◽  
I Virtanen ◽  
J Wartiovaara ◽  
S Stenman
Keyword(s):  
Binding Sites ◽  
Human Fibroblasts ◽  
T Antigen ◽  
Similar Distribution ◽  
Sv40 T Antigen ◽  
Con A ◽  
Acetone Treatment ◽  
Nonionic Detergent ◽  
Detergent Treatment ◽  
Scanning Electron

Nonionic detergent (NP40) treatment of paraformaldehyde-fixed normal and SV40-transformed human fibroblasts resulted in intracellular penetration of two chosen fluorescent antibodies and Concanavalin A (Con A). After the detergent treatment nuclear SV40 T antigen, cytoplasmic fibronectin glycoprotein and Con A binding sites could be visualized in fluorescence microscopy. The lowest NP40 concentration which made fixed cells permeable was 0.05%. The morphology of cells was preserved better by this new method than by conventional fixation methods, such as acetone treatment. In scanning electron microscopy the surface of the fixed NP40-treated cells had only small rugosities and fine pores. The subsurface cytoskeleton especially was well preserved and had a more distinct fine structure. The improved morphology made it possible to detect a similar distribution of fibronectin and Con A binding sites in the perinuclear endoplasmic reticulum regions.

scholarly journals Visualization of intracellular concanavalin A binding sites in retinal photoreceptors.

1978 ◽  
Vol 26 (10) ◽  
pp. 822-828 ◽  
Author(s):  
I Nir
Keyword(s):  
Concanavalin A ◽  
Binding Sites ◽  
Photoreceptor Cells ◽  
Con A ◽  
Thin Sections ◽  
Glycol Methacrylate ◽  
Outer Segments ◽  
Retinal Photoreceptors ◽  
Carbohydrate Components ◽  
The Relationship

Localization of carbohydrate components in retinal photoreceptor cells and membranes was studied. Frog and rat retinas were fixed with glutaraldehyde and embedded in glycol methacrylate or in a mixture of glycol methacrylate, glutaraldehyde and urea. Thin sections were incubated with ferritin-labeled concanavalin A (F-Con A) and stained with osmium vapors. Intensive binding was observed in both rod and cone outer segments. In the rod inner segment, differential binding of F-Con A was demonstrated. While numerous ferritin granules were observed in the myoid zone, only a few were seen in the ellipsoid zone, except for a local accumulation along the plasma membrane. In the rod outer segment, Con A binding sites were closely associated with the disk membranes. Ferritin granules were observed on both sides of the membranes. The relationship between the localization of Con A binding sites and the orientation of visual pigment molecules within the rod outer segments disk membranes was discussed.

Differences in density of Concanavalin A-binding sites due to differences in surface morphology of suspended normal and transformed 3T3 fibroblasts

1975 ◽  
Vol 19 (1) ◽  
pp. 21-32
Author(s):  
J.G. Collard ◽  
J.H. Temmink
Keyword(s):  
Surface Morphology ◽  
Concanavalin A ◽  
Binding Sites ◽  
3T3 Cells ◽  
Con A ◽  
3T3 Fibroblasts ◽  
Transformed Fibroblasts ◽  
Transmission Electron ◽  
The Difference ◽  
Electron Microscopes

Calculations of the density of Concanavalin A (Con A)-binding sites on normal and transformed fibroblasts have, as yet, been based on the unproven assumption that suspended cells are smooth spheres. We studied the surface morphology of suspended normal and transformed fibroblasts with scanning and transmission electron microscopes, and found a large difference in surface morphology between suspended normal and transformed 3T3 cells. When this difference in surface morphology was taken into account, the estimated cell surface area of normal 3T3 cells was approximately seven times larger than that of transformed 3T3 cells. Since equal numbers of 3H-Con A molecules are bound on normal and transformed cells, the density of Con A-binding sites is approximately seven times greater on transformed than on normal 3T3 cells. The difference in density of Con A-binding sites between normal and transformed fibroblasts might be sufficient to explain the difference in agglutination response, as originally suggested by Burger, and may also be the cause of the different degrees of clustering of Con A-binding sites on the plasma membrane of these cells.

Genomic and metabolomic analysis of step-wise malignant transformation in human skin fibroblasts

2019 ◽  
Vol 41 (5) ◽  
pp. 656-665
Author(s):  
Anastasia Kariagina ◽  
Sophia Y Lunt ◽  
J Justin McCormick
Keyword(s):  
Malignant Transformation ◽  
Human Fibroblasts ◽  
Glucose Consumption ◽  
Tca Cycle ◽  
Transformed Cells ◽  
Aminooxyacetic Acid ◽  
Malignant Cells ◽  
The Impact

Abstract Metabolic changes accompanying a step-wise malignant transformation was investigated using a syngeneic lineage of human fibroblasts. Cell immortalization was associated with minor alterations in metabolism. Consecutive loss of cell cycle inhibition in immortalized cells resulted in increased levels of oxidative phosphorylation (OXPHOS). Overexpression of the H-Ras oncoprotein produced cells forming sarcomas in athymic mice. These transformed cells exhibited increased glucose consumption, glycolysis and a further increase in OXPHOS. Because of the markedly increased OXPHOS in transformed cells, the impact of a transaminase inhibitor, aminooxyacetic acid (AOA), which decreases glutamine influx to the tricarboxylic acid (TCA) cycle, was tested. Indeed, AOA significantly decreased proliferation of malignantly transformed fibroblasts and fibrosarcoma-derived cells in vitro and in vivo. AOA also decreased proliferation of cells susceptible to malignant transformation. Metabolomic studies in normal and transformed cells indicated that, in addition to the anticipated effect on the TCA cycle, AOA decreased production of nucleotides adenosine triphosphate (ATP) and uridine monophosphate. Exogenous nucleotides partially rescued decreased proliferation of the malignant cells treated with AOA. Our data indicate that AOA blocks several metabolic pathways essential for growth of malignant cells. Therefore, OXPHOS may provide important therapeutic targets for treatment of sarcoma.

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