scholarly journals Biosynthesis, surface expression and function of the fibronectin receptor after rat liver cell transformation to tumorigenicity

1993 ◽  
Vol 291 (1) ◽  
pp. 247-255 ◽  
Author(s):  
M Decastel ◽  
M A Doyennette-Moyne ◽  
E Gouet ◽  
M Aubery ◽  
P Codogno
Keyword(s):  
Molecular Mass ◽  
Hepatoma Cell ◽  
Rat Hepatocytes ◽  
Hepatoma Cells ◽  
Rat Hepatocyte ◽  
Fibronectin Receptor ◽  
Zajdela Hepatoma ◽  
Sds Page ◽  
Normal Rat ◽  
And Function

Zajdela hepatoma cells are poorly-adherent cells derived from an undifferentiated tumour and transplanted into rat. We compared the biosynthesis, structure and function of the fibronectin receptor in normal rat hepatocytes with that in Zajdela hepatoma cells. The rat hepatocyte fibronectin receptor has been isolated. It is composed of two subunits: alpha 5 (molecular mass 155 kDa) and beta 1 (molecular mass 115 kDa). However, its biosynthesis has not yet been described. Using polyclonal antibodies raised against each of the subunits of the receptor, we observed that the alpha 5-subunit was synthesized as a 155-kDa polypeptide in normal rat hepatocytes and Zajdela hepatoma cells. In contrast, the molecular mass of the beta 1-subunit was 130 kDa in Zajdela hepatoma cells versus 115 kDa in normal rat hepatocytes. Pulse-chase experiments showed that the apparent transition time from the 100-kDa beta 1-precursor to the 130-kDa mature form was abnormally prolonged in Zajdela hepatoma cells since the latter was not detected until 24 h, while the transition from the 100-kDa precursor to the 115-kDa mature form began within 3 h in normal rat hepatocytes. Digestion of both the normal rat hepatocytes and Zajdela hepatoma cells 100-kDa beta 1-precursors with endo-beta-N-acetylglucosaminidase H and peptide N-glycosidase yielded products from 100 kDa to 84 kDa and 82 kDa, respectively, as judged by SDS/PAGE, suggesting that the same polypeptide chain is synthesized in normal rat hepatocytes and in Zajdela hepatoma cells. Incubation of the mature normal rat hepatocyte beta 1-subunit with peptide N-glycosidase reduced its molecular mass from 115 kDa to 82 kDa, as judged by SDS/PAGE, while the molecular mass of the abnormal mature Zajdela hepatoma cell beta 1-subunit decreased from 130 to 110 kDa. Thus, in addition to alterations in the Asn-linked oligosaccharide processing, ‘ascitic growth’ induced other post-translational modifications in the Zajdela hepatoma cell beta 1-subunit. Furthermore, both the abnormal mature 130-kDa and precursor 100-kDa beta 1-subunits were detected on the surface of Zajdela hepatoma cells, associated with the alpha 5-subunit. The relationship between these structural alterations in the fibronectin receptor and the impaired Zajdela hepatoma cell binding to soluble fibronectin or to a coated fibronectin matrix that was observed in this study is discussed.

Role of ATP7B in biliary copper excretion in a human hepatoma cell line and normal rat hepatocytes

2000 ◽  
Vol 118 (5) ◽  
pp. 921-928 ◽  
Author(s):  
Masaru Harada ◽  
Shotaro Sakisaka ◽  
Kunihiko Terada ◽  
Rina Kimura ◽  
Takumi Kawaguchi ◽  
...  
Keyword(s):  
Cell Line ◽  
Hepatoma Cell ◽  
Rat Hepatocytes ◽  
Hepatoma Cell Line ◽  
Human Hepatoma ◽  
Human Hepatoma Cell ◽  
Copper Excretion ◽  
Human Hepatoma Cell Line ◽  
Normal Rat

Erratum to “glutathione S-transferases and P-glycoprotein in normal rat hepatocytes and hepatoma cells: analysis using flow cytometry”

1995 ◽  
Vol 89 (2) ◽  
pp. 231
Author(s):  
Rekha Mehta ◽  
Hugh G. Davis ◽  
Gary W. Laver ◽  
Paul R. Rowsell ◽  
Genevieve S. Bondy
Keyword(s):  
Flow Cytometry ◽  
Rat Hepatocytes ◽  
Hepatoma Cells ◽  
P Glycoprotein ◽  
Glutathione S Transferases ◽  
Normal Rat

Immunofluorescent localization of type II insulin-like growth factor receptor in rat liver and hepatoma cells

1989 ◽  
Vol 121 (2) ◽  
pp. 221-NP ◽  
Author(s):  
M. A. Hartshorn ◽  
C. D. Scott ◽  
R. C. Baxter
Keyword(s):  
Rat Liver ◽  
Hepatoma Cell ◽  
Rat Hepatocytes ◽  
Hepatoma Cells ◽  
Type Ii ◽  
Adult Rat ◽  
Hepatoma Cell Lines ◽  
Igf Receptors ◽  
Immunofluorescent Technique ◽  
Igf Receptor

ABSTRACT We have used an immunofluorescent technique to localize type II insulin-like growth factor (IGF) receptors in rat liver, rat hepatocytes and three rat hepatoma cell lines (HTC, H-35 and 5123) using a polyclonal antibody (C-1) raised to purified rat liver type II IGF receptor. Specificity of the antiserum was confirmed by Western blotting of microsomal membranes prepared from hepatocytes and hepatoma cells which showed a single class of receptor in all cells, of Mr approximately 210 000 for hepatocytes, HTC and H-35 cells and approximately 220 000 for 5123 cells, on non-reduced, 4–15% polyacrylamide gradient gels. The specificity of the immunofluorescent technique was also verified by abolition of labelling after preincubation of antiserum with purified type II IGF receptor. Rat liver cryosections contained areas of juxtanuclear labelling in hepatocytes, consistent with the presence of type II IGF receptor in the Golgi region. Brightest immunofluorescence was seen in sections from fetal and neonatal rats with adult rat hepatocytes staining brightly only around central veins. Areas of labelling were also seen in connective tissue surrounding larger veins. Cultured adult rat hepatocytes and rat hepatoma cell lines also showed bright areas of juxtanuclear immunofluorescence, with HTC and H-35 cells staining more than 5123 and adult hepatocytes. Fetal rat hepatocytes in culture also labelled very brightly both in a juxtanuclear location and in small clusters over the cell, possibly on the cell surface. These observations indicate that type II IGF receptors are located predominantly on intracellular membranes and are most abundant in rapidly growing cells and tissues (such as fetal liver and hepatoma cells). Journal of Endocrinology (1989) 121, 221–227

Use of Cultured Hepatoma Cell Lines in the Assessment of Aldehyde Metabolism

1992 ◽  
Vol 20 (1) ◽  
pp. 77-83
Author(s):  
Margherita Ferro ◽  
Anna Maria Bassi ◽  
Susanna Penco ◽  
Sandra Piana ◽  
Giambattista Ravera ◽  
...  
Keyword(s):  
Cell Line ◽  
Cell Lines ◽  
Hepatoma Cell ◽  
Rat Hepatocytes ◽  
Experimental Conditions ◽  
Major Pathway ◽  
Hepatoma Cell Lines ◽  
Normal Rat ◽  
Htc Cells

Aldehyde dehydrogenases (ALDH) represent a major pathway for the enzymatic removal of many potentially toxic aldehydes. The purpose of this study was to examine the basal levels of ALDH in five hepatoma cell lines chosen as representatives of three different species (man, rat, mouse) and their inducibility by some xenobiotics. Human HepG2, rat MH1C1, HTC, H4IIEC3 and mouse Hepa 1c1c7 cell lines were grown as monolayers. The ALDH activities were determined in cell homogenates from both unexposed control cultures and cells exposed to phenobarbital (PB), 3-methylcholanthrene (MC) and β-naphthoflavone (BNF). The ALDH activity was detected using benzaldehyde (BA) and propionaldehyde (PA) as substrates and both NAD and NADP as co-enzymes. Great variability in basal ALDH levels was found in the five cell lines: BA/NAD and BA/NADP enzyme activities were very high in the HTC cell line, intermediate in MH1C1 cells (near to normal rat hepatocytes) and very low in the remaining three cell lines. In HTC cells only, the PA/NAD activity was slightly induced by PB, but it remained unchanged under all the other experimental conditions. MH1C1 cells showed highly significant increases of all the activities with MC and BNF (up to 10-fold). The low basal activity of the H4IIEC3 cell line was significantly increased by MC and BNF, but only with BA/NADP. The Hepa 1c1c7 cell line responded only to BNF, as inducing compound, whereas the low basal enzyme levels of the human-derived HepG2 cell line were not significantly increased. These results suggest various applications of hepatoma cell cultures in in vitro toxicology.

scholarly journals Control and function of the transamination pathways of glutamine oxidation in tumour cells

1991 ◽  
Vol 273 (2) ◽  
pp. 271-275 ◽  
Author(s):  
Z Kovačević ◽  
O Brkljač ◽  
K Bajin
Keyword(s):  
Malic Enzyme ◽  
Hepatoma Cell ◽  
Ehrlich Ascites Carcinoma ◽  
Similar Rate ◽  
Hepatoma Cells ◽  
Metabolizing Enzymes ◽  
Cell Plasma ◽  
Ehrlich Ascites ◽  
And Function ◽  
Low Activity

Parallel investigations of the transamination pathways of glutamine oxidation in Ehrlich ascites carcinoma (EAC) and AS 30D hepatoma revealed that hepatoma cells, unlike EAC, produce very little aspartate. This cannot be explained by differences in the activity of glutamine-metabolizing enzymes. Also, the mitochondria from the hepatoma respired at a similar rate to EAC mitochondria with glutamine as sole substrate producing substantial amounts of aspartate. Unlike their isolated mitochondria, intact hepatoma cells showed a very low rate of glutamine oxidation. Compared with EAC, the rate of L-[U-14C]glutamine consumption by AS 30D hepatoma cells was much lower, with insignificant production of 14C-labelled aspartate and CO2. This suggested that the glutamine-transporting system in the hepatoma cell plasma membrane had a very low activity. Isolated hepatoma mitochondria produced 3 times more pyruvate from malate than did EAC mitochondria, indicating a higher activity of NAD(P)-dependent malic enzyme. We postulate that an active malic enzyme may suppress the synthesis of aspartate in hepatoma cells, but further evidence is needed to confirm this assumption.

Recycling of the asialoglycoprotein receptor: biochemical and immunocytochemical evidence

1982 ◽  
Vol 300 (1099) ◽  
pp. 229-235 ◽  
Keyword(s):  
Cell Surface ◽  
Hepatoma Cell ◽  
Rat Hepatocytes ◽  
Cell System ◽  
Coated Vesicles ◽  
Double Labelling ◽  
Human Hepatoma Cell ◽  
Electron Microscopic ◽  
Sinusoidal Cell ◽  
Normal Rat

One of the best documented systems of receptor-mediated endocytosis is the clearance of asialoglycoproteins (ASGP) from the blood plasma by liver parenchymal cells. There are 200000-500000 ligand binding sites per cell, which makes this system favourable for molecular studies of receptor function. By using both biochemical and immunocytochemical approaches, we have obtained evidence for receptor recycling. We have also localized the intracellular site at which the endocytosed receptor and ligand dissociate. The human hepatoma cell Hep G2 contains abundant ASGP receptors (approximately 225000 per cell). In growing cells approximately 85% of the functional receptors are on the cell surface and the remaining 15% are internal. The maximal rate of ligand uptake in this cell system at 37 °C is approximately 30000 molecules per cell per minute. Each functional receptor can therefore bind and internalize more than 50 ligand molecules during a 6 h period (in the absence of new receptor synthesis), or one ligand each 8 min. To follow both ligand and receptor during their common endocytosis and to visualize the compartment in which the dissociation of ligand from receptor occurs, we have used our recently developed double-labelling immunocytochemical electron microscopic techniques with purified antibodies against ASGP ligand and ASGP receptor. In normal rat hepatocytes, both ligand and receptor are taken up from the sinusoidal cell surface in clathrin-coated vesicles. Both receptor and ligand are associated with the membrane of small clathrin-coated vesicles close to the cell surface. Larger vesicles, farther removed from the surface, contain ligand accumulated within the lumen. The membranes of these larger vesicles contain little receptor, but receptor was concentrated in detached vesiculotubular extensions, which were largely free of ligand. These vesicles represent the compartment of uncoupling of receptor and ligand (CURL) during their common endocytosis. Ligand contained within the vesicle lumen is then transferred to multivesicular bodies and lysosomes; the tubular extensions may carry receptor back to the cell surface.

Glutathione S-transferases and P-glycoprotein in normal rat hepatocytes and hepatoma cells: analysis using flow cytometry

1994 ◽  
Vol 84 (2) ◽  
pp. 163-172 ◽  
Author(s):  
Rekha Mehta ◽  
Hugh G. Davis ◽  
Gary W. Laver ◽  
Paul R. Rowsell ◽  
Genevieve S. Bondy
Keyword(s):  
Flow Cytometry ◽  
Rat Hepatocytes ◽  
Hepatoma Cells ◽  
P Glycoprotein ◽  
Glutathione S Transferases ◽  
Normal Rat
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