Isotopomer spectral analysis of cholesterol synthesis: applications in human hepatoma cells

1994 ◽  
Vol 266 (3) ◽  
pp. E384-E395 ◽  
Author(s):  
J. K. Kelleher ◽  
A. T. Kharroubi ◽  
T. A. Aldaghlas ◽  
I. B. Shambat ◽  
K. A. Kennedy ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Cholesterol Synthesis ◽  
Hepatoma Cell ◽  
Gas Chromatography Mass Spectrometry ◽  
Hepatoma Cell Line ◽  
Human Hepatoma ◽  
Human Hepatoma Cells ◽  
Unknown Parameters ◽  
Human Hepatoma Cell ◽  
Cholesterol Precursors

Cholesterol synthesis from 13C-labeled precursors produces a discrete spectrum of mass isotopomers detectable using gas chromatography-mass spectrometry. The isotopomer spectral analysis (ISA) method matches the observed spectrum of cholesterol isotopomers with a mathematical model to obtain the best fit of model spectrum to data spectrum. The model was based on multinomial probability expressions that simulate cholesterol synthesis as a condensation of mevalonate fragments. As many as four unknown parameters, representing fluxes between compartments, were included in the model. Models were developed to assess cholesterol synthesis from 13C-enriched precursors including mevalonate, acetate, acetoacetate or octanoate. Models were tested in the human hepatoma cell line, Hep G2, which readily incorporated the 13C substrates into cholesterol. The ISA approach was used to estimate the fractional amount of the cholesterol precursors derived from the 13C substrate and the fraction of total cellular cholesterol synthesized in the presence of the 13C substrate. The study demonstrated the feasibility of the ISA approach for a condensation biosynthesis that is not a simple polymerization and for models with more than two unknown parameters.

Inhibitory Effects of Lycopene on the Adhesion, Invasion, and Migration of SK-Hep1 Human Hepatoma Cells

2006 ◽  
Vol 231 (3) ◽  
pp. 322-327 ◽  
Author(s):  
Eun-Sun Hwang ◽  
Hyong Joo Lee
Keyword(s):  
Cell Growth ◽  
Hepatoma Cell ◽  
Hepatoma Cells ◽  
Hepatoma Cell Line ◽  
Dependent Manner ◽  
Human Hepatoma ◽  
Human Hepatoma Cells ◽  
Human Hepatoma Cell ◽  
Invasion And Migration ◽  
And Migration

Lycopene, which is the predominant carotenoid in tomatoes and tomato-based foods, may protect humans against various cancers. Effects of lycopene on the adhesion, invasion, migration, and growth of the SK-Hep1 human hepatoma cell line were investigated. Lycopene inhibited cell growth in dose-dependent manners, with growth inhibition rates of 5% and 40% at 0.1 μM and 50 μM lycopene, respectively, after 24 hrs of incubation. Similarly, after 48 hrs of incubation, lycopene at 5 μM and 10 μM decreased the cell numbers by 30% and 40%, respectively. Lycopene decreased the gelatinolytic activities of both matrix metalloproteinase (MMP)-2 and MMP-9, which were secreted from the SK-Hep1 cells. Incubation of SK-Hep1 cells with 110 μM of lycopene for 60 mins significantly inhibited cell adhesion to the Matrigel-coated substrate in a concentration-dependent manner. To study invasion, SK-Hep1 cells were grown either on Matrigel-coated Transwell membranes or in 24-well plates. The cells were treated sequentially for 24 hrs with lycopene before the start of the invasion assays. Cell growth and death were assessed under the same conditions. The invasion of SK-Hep1 cells treated with lycopene was significantly reduced to 28.3% and 61.9% of the control levels at 5 μM and 10 μM lycopene, respectively (P < 0.05). In the migration assay, lycopene-treated cells showed lower levels of migration than untreated cells. These results demonstrate the antimetastatic properties of lycopene in inhibiting the adhesion, invasion, and migration of SK-Hep1 human hepatoma cells.

Cyclic AMP decseases LDL catabolism and cholesterol synthesis in the human hepatoma cell line HepG2

1988 ◽  
Vol 156 (1) ◽  
pp. 424-431 ◽  
Author(s):  
Cécile Maziere ◽  
Jean-Claude Maziere ◽  
Suzanne Salmon ◽  
Martine Auclair ◽  
Liliana Mora ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Cell Line ◽  
Cholesterol Synthesis ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Human Hepatoma ◽  
Human Hepatoma Cell ◽  
Human Hepatoma Cell Line ◽  
Hepatoma Cell Line Hepg2 ◽  
Ldl Catabolism

scholarly journals Phorbol ester inhibits erythropoietin production in human hepatoma cells (Hep G2)

1992 ◽  
Vol 262 (5) ◽  
pp. C1204-C1210 ◽  
Author(s):  
A. Kurtz ◽  
K. U. Eckardt ◽  
C. Pugh ◽  
P. Corvol ◽  
D. Fabbro ◽  
...  
Keyword(s):  
Phorbol Ester ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Maximal Effect ◽  
Mrna Levels ◽  
Human Hepatoma ◽  
Low Oxygen ◽  
Hep G2 ◽  
Human Hepatoma Cells ◽  
Human Hepatoma Cell

Using the human hepatoma cell line Hep G2, we have studied a possible role of protein kinase C (PKC) activity for regulation of erythropoietin (EPO) production. During a 72-h incubation, EPO production by the cells was stimulated sevenfold by exposure to low oxygen tension (1%) and threefold by exposure to cobaltous chloride (100 microM). The phorbol ester phorbol 12-myristate-13 acetate (PMA) led to a concentration-dependent inhibition of basal and stimulated EPO formation (ED50 10 nM). This decrease of EPO production, which was apparent already after 1 h of incubation with PMA, reached its maximal effect after 24 h and held on for 72 h. It was paralleled by an inhibition of the increase of EPO mRNA levels in response to stimulation. A 24-h preincubation of the cells with PMA (100 nM) virtually blunted the effect of hypoxia on EPO formation. Recovery of EPO synthesis after removal of PMA took 48-72 h. The effect of PMA on EPO production was mimicked by phorbol 12,13-dibutyrate (ED50 1 microM) but not by 4 alpha-phorbol 12,13-didecanoate. The synthetic diacylglycerol analogues oleolyl-acetylglycerol and dioctanoylglycerol (2-200 microM) also had no effect on either basal or stimulated EPO production. Treatment with PMA caused a translocation of the alpha-isoenzyme of PKC from the cytosol to the membrane after 1 h and a disappearance of the membrane-bound form after 24 h of incubation. Staurosporine and 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine, two structurally different inhibitors of PKC activity, inhibited basal and stimulated EPO production with ED50 values of 9 nM and 50 microM, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Effect of lysosomotropic amines on the secretory pathway and on the recycling of the asialoglycoprotein receptor in human hepatoma cells.

1985 ◽  
Vol 101 (2) ◽  
pp. 531-539 ◽  
Author(s):  
G J Strous ◽  
A Du Maine ◽  
J E Zijderhand-Bleekemolen ◽  
J W Slot ◽  
A L Schwartz
Keyword(s):  
Golgi Complex ◽  
Intracellular Transport ◽  
Secretory Pathway ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Human Hepatoma ◽  
Receptor Recycling ◽  
Human Hepatoma Cells ◽  
Human Hepatoma Cell ◽  
Response Characteristics

We studied the intracellular transport of secretory and membrane proteins in the human hepatoma cell line HepG-2 infected with vesicular stomatitis virus. Cells were pulse-labeled in the presence of [35S]methionine and chased in the presence of the lysosomotropic agent primaquine. At a concentration of 0.3 mM primaquine effectively inhibited the secretion of albumin and, to a lesser extent, that of orosomucoid and transferrin. The drug also prevented the budding of virus particles at the cell surface. The intracellular transport to the Golgi complex of the membrane protein VSV-G was not affected by primaquine as it acquires resistance to endo-beta-N-acetylglucosaminidase H at the same rate as in control cells. Addition of primaquine at various times after the initiation of the chase period indicates that the effect of primaquine occurs just before secretion. In confirmation of the biochemical data, immunocytochemical localization of albumin in cells treated with NH4Cl demonstrated that albumin accumulated in vesicles at the trans side of the Golgi complex. The effect of primaquine on secretion was also compared with its effect on receptor recycling. The dose-response characteristics of the effect of primaquine on receptor recycling are identical to those of the effects on protein secretion and virus budding. These results indicate that both processes involve the same transport mechanism, and/or that they occur via at least one identical intracellular compartment.

scholarly journals Immunodetection and molecular cloning of a bile-salt-dependent lipase isoform in HepG2 cells

1999 ◽  
Vol 342 (1) ◽  
pp. 179-187 ◽  
Author(s):  
Alain VÉRINE ◽  
Nadine BRUNEAU ◽  
Anne VALETTE ◽  
Josette LE PETIT-THEVENIN ◽  
Eric PASQUALINI ◽  
...  
Keyword(s):  
Bile Salt ◽  
Molecular Mass ◽  
Hepg2 Cells ◽  
Hepatoma Cell ◽  
Pancreatic Enzyme ◽  
Hepatoma Cell Line ◽  
Human Pancreas ◽  
Human Hepatoma ◽  
Human Hepatoma Cells ◽  
Human Hepatoma Cell

In this article, we report the nucleotide sequence of the cDNA encoding an isoform of bile-salt-dependent lipase (BSDL) expressed by human hepatoma cells. The BSDL is a 100-kDa glycoprotein normally expressed by the human pancreas. Using a polyclonal antibody raised against an internal peptide located between Ile327 and Glu350 of the human pancreatic BSDL, we have immunodetected an isoform of human pancreatic BSDL, with an apparent molecular mass of about 62 kDa. This isoform of BSDL was mainly associated with the cytosol of a human hepatoma cell line (HepG2), the remaining protein being found in the microsome fraction. In addition, esterolytic activity on p-nitrophenyl hexanoate measured in microsomes and cytosol appeared very low and was weakly stimulated by bile salts, such as taurocholate. In contrast to human pancreatic BSDL, which is secreted as a component of pancreatic juice, this isoform appeared to be retained in the HepG2 cells. Reverse transcription, followed by PCR and amplification, performed on RNA extracted from HepG2 cells using specific primers hybridizing to the sequence coding for the entire normal human pancreatic BSDL, allowed us to amplify a 1.7-kb transcript that appeared to be 0.5 kb shorter than the transcript of the pancreatic enzyme (2.2 kb). From the sequence of the transcript thus obtained, a protein with a molecular mass of 62 kDa might be predicted, which is in good agreement with the size of the isoform of BSDL immunodetected in HepG2 cells. The N-terminal amino-acid sequence, deduced from the 1.7-kb transcript sequence, matched that of the pancreatic BSDL. However, the C-terminal domain appeared truncated, bearing only a single mucin-like sequence compared with sixteen for the human pancreatic BSDL. The actual intracellular function of this human BSDL hepatoma isoform remains to be elucidated.

scholarly journals Hep3B Human Hepatoma Cells Support Replication of the Wild-Type and a 5′-End Deletion Mutant GB Virus B Replicon

2003 ◽  
Vol 77 (22) ◽  
pp. 11875-11881 ◽  
Author(s):  
Amedeo De Tomassi ◽  
Maura Pizzuti ◽  
Cinzia Traboni
Keyword(s):  
Cell Clone ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Human Hepatoma ◽  
Wild Type ◽  
Human Hepatoma Cells ◽  
Human Hepatoma Cell ◽  
Stem Loop ◽  
Adaptive Mutations ◽  
Huh7 Cells

ABSTRACT Hepatitis C virus (HCV) and GB virus B (GBV-B) replicons have been reported to replicate only in Huh7 cells. Here we demonstrate that subpopulations of another human hepatoma cell line, Hep3B, are permissive for the GBV-B replicon, showing different levels of enhancement of replication from those of the unselected parental cell population. Adaptive mutations are not required for replication of the GBV-B replicon in these cells, as already demonstrated for Huh7 cells. Nonetheless, we identified a mutant replicon in one of the selected cell lines, which, although lacking the 5′ end proximal stem-loop, is able to replicate in Hep3B cells as well as in Huh7 cells. This mutant indeed shows a higher replication efficiency than does wild-type replicon, especially in the Hep3B cell clone from which it was originally recovered. This indicates that the stem-loop Ia is not necessary for replication of the GBV-B replicon in human cells, unlike what occurs with HCV, and that its absence can even provide a selective advantage.

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