scholarly journals Evidence for trans regulation of apoptosis in intertypic somatic cell hybrids.

1994 ◽  
Vol 14 (9) ◽  
pp. 6125-6134 ◽  
Author(s):  
H Gourdeau ◽  
P R Walker
Keyword(s):  
Cell Death ◽  
Somatic Cell ◽  
Cell Line ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Suspension Cells ◽  
Glucocorticoid Treatment ◽  
Cell Hybrids ◽  
Genetic Components ◽  
Cell Death Pathway

The genetic components required for glucocorticoid induction of apoptosis were studied by using somatic cell hybridization. Intertypic whole-cell hybrids were generated by crossing the glucocorticoid-resistant rat liver cell line Fado-2 with the glucocorticoid-sensitive mouse thymoma cell line BW5147.3. Morphological and biochemical criteria were used to assess sensitivity or resistance to glucocorticoid-induced cell death. Both phenotypes were observed, and all of the hybrids retained a functional glucocorticoid receptor as judged by their abilities to induce the metallothionein gene in response to dexamethasone (Dex). Sensitivity to apoptosis did not correlate with morphological phenotype in that not all suspension cells were sensitive. The effect of glucocorticoids on the expression of apoptosis-linked genes was analyzed in a subset of Dex-sensitive and Dex-resistant hybrids. p53 and c-myc mRNAs were present in parental cells as well as sensitive and resistant hybrid cells, and their levels were not affected by glucocorticoid treatment. bcl-2 expression was restricted to the thymoma cell line and was also not affected by glucocorticoids. We did not detect any bcl-2 mRNA in the hepatoma cell line and the hybrids, suggesting that, as with most tissue-specific genes, bcl-2 is regulated in trans. Furthermore, while the majority of hybrids analyzed retained a full complement of mouse chromosomes, sensitive hybrids were missing some rat chromosomes (preferentially chromosomes 16 and 19), indicating that apoptosis is subject to trans repression. Resistant cells thus appear to repress the activity or synthesis of a nuclear factor that interacts with a glucocorticoid-dependent gene(s) to activate the cell death pathway.

Evidence for trans regulation of apoptosis in intertypic somatic cell hybrids

1994 ◽  
Vol 14 (9) ◽  
pp. 6125-6134
Author(s):  
H Gourdeau ◽  
P R Walker
Keyword(s):  
Cell Death ◽  
Somatic Cell ◽  
Cell Line ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Suspension Cells ◽  
Glucocorticoid Treatment ◽  
Cell Hybrids ◽  
Genetic Components ◽  
Cell Death Pathway

The genetic components required for glucocorticoid induction of apoptosis were studied by using somatic cell hybridization. Intertypic whole-cell hybrids were generated by crossing the glucocorticoid-resistant rat liver cell line Fado-2 with the glucocorticoid-sensitive mouse thymoma cell line BW5147.3. Morphological and biochemical criteria were used to assess sensitivity or resistance to glucocorticoid-induced cell death. Both phenotypes were observed, and all of the hybrids retained a functional glucocorticoid receptor as judged by their abilities to induce the metallothionein gene in response to dexamethasone (Dex). Sensitivity to apoptosis did not correlate with morphological phenotype in that not all suspension cells were sensitive. The effect of glucocorticoids on the expression of apoptosis-linked genes was analyzed in a subset of Dex-sensitive and Dex-resistant hybrids. p53 and c-myc mRNAs were present in parental cells as well as sensitive and resistant hybrid cells, and their levels were not affected by glucocorticoid treatment. bcl-2 expression was restricted to the thymoma cell line and was also not affected by glucocorticoids. We did not detect any bcl-2 mRNA in the hepatoma cell line and the hybrids, suggesting that, as with most tissue-specific genes, bcl-2 is regulated in trans. Furthermore, while the majority of hybrids analyzed retained a full complement of mouse chromosomes, sensitive hybrids were missing some rat chromosomes (preferentially chromosomes 16 and 19), indicating that apoptosis is subject to trans repression. Resistant cells thus appear to repress the activity or synthesis of a nuclear factor that interacts with a glucocorticoid-dependent gene(s) to activate the cell death pathway.

scholarly journals Suppression of liver cell apoptosis in vitro by the non-genotoxic hepatocarcinogen and peroxisome proliferator nafenopin.

1994 ◽  
Vol 125 (1) ◽  
pp. 197-203 ◽  
Author(s):  
A C Bayly ◽  
R A Roberts ◽  
C Dive
Keyword(s):  
Cell Death ◽  
Cell Line ◽  
Liver Cell ◽  
Hepatoma Cell ◽  
Chromatin Condensation ◽  
Hepatoma Cell Line ◽  
Peroxisome Proliferator ◽  
Tgf Beta ◽  
Induced Apoptosis ◽  
Co Addition

Suppression of apoptosis has been implicated as a mechanism for the hepatocarcinogenicity of the peroxisome proliferator class of non-genotoxic carcinogens. The ability of the peroxisome proliferator nafenopin to suppress or delay the onset of liver apoptosis was investigated using primary cultures of rat hepatocytes and the Reuber hepatoma cell line FaO. 50 microM nafenopin reversibly maintained the viability of primary rat hepatocyte cultures which otherwise degenerated within 8 d of establishment. The maintenance of viability of hepatocyte monolayers was associated with a significant decrease in the number of cells exhibiting chromatin condensation patterns typical of apoptosis. Apoptosis could be induced in hepatocytes by administration of 5 ng/ml TGF beta 1. Co-addition of 50 microM nafenopin significantly reduced TGF beta 1-induced apoptosis by 50-60%. TGF beta 1 (1-5 ng/ml) also induced apoptosis in the FaO rat hepatoma cell line. Cell death was accompanied by detachment of FaO cells from the monolayer and detached cells exhibited chromatin condensation and non-random DNA fragmentation patterns typical of apoptosis. Co-addition of 50 microM nafenopin to TGF beta 1-treated FaO cultures significantly reduced the number of apoptotic cells detaching from the monolayer at 24 h. In contrast, nafenopin had no significant effect on FaO apoptosis induced by the DNA damaging agents etoposide and hydroxyurea. We conclude that suppression of liver cell death by apoptosis may play a role in the hepatocarcinogenicity of the peroxisome proliferators, although the extent of this protection is dependent on the nature of the apoptotic stimulus.

Non-genotoxic hepatocarcinogenesis in vitro: the FaO hepatoma line responds to peroxisome proliferators and retains the ability to undergo apoptosis

1993 ◽  
Vol 104 (2) ◽  
pp. 307-315 ◽  
Author(s):  
A.C. Bayly ◽  
N.J. French ◽  
C. Dive ◽  
R.A. Roberts
Keyword(s):  
Cell Death ◽  
Cell Line ◽  
Cell Lines ◽  
Hepatoma Cell ◽  
Hepatoma Cell Line ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferators ◽  
Hepatoma Cell Lines

A range of hepatoma cell lines (RH1, HTC, FaO, 7800C1 and MH1C1), has been studied with the aim of establishing an in vitro model to investigate the molecular mechanisms of hepatocarcinogenicity induced by the peroxisome proliferator class of non-genotoxic carcinogens. In view of speculation that peroxisome proliferators suppress hepatocyte apoptosis in vivo, we have placed particular emphasis on evaluating whether hepatoma cell lines retain the ability to undergo apoptotic cell death. Expression of the liver-specific differentiation marker albumin and the peroxisome proliferator-activated receptor (PPAR) was highest in the Reuber hepatoma cell line, FaO. This cell line also demonstrated the most marked response to the peroxisome proliferator nafenopin with a 2.2-fold induction of the microsomal enzyme cytochrome p450IVA1. This response was found to display intercellular heterogeneity by immunocytochemistry. Thus, the FaO cell line maintained characteristics of hepatocytes, both in vivo and in vitro, in terms of expression of constitutive and inducible markers. However, none of the cell lines tested mirrored the hyperplastic response of hepatocytes to nafenopin, since no increase in cell growth kinetics was observed on addition of nafenopin to the growth medium. The mode of cell death in confluent FaO cultures was characterised as apoptosis, by fluorescence microscopy and agarose gel electrophoresis of extracted DNA. Cells detaching from confluent FaO cultures exhibited chromatin condensation and DNA fragmentation patterns characteristic of cels undergoing apoptotic death.Interestingly, no apoptosis was seen in monolayer cells, suggesting that apoptosis in vitro is associated with cell shrinkage and detachment similar to that documented for the liver in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Expression of insulin receptors and insulin action in cell hybrids and cybrids

1983 ◽  
Vol 214 (2) ◽  
pp. 309-316
Author(s):  
C R Kahn ◽  
V Lauris ◽  
M Fehlmann ◽  
M Crettaz
Keyword(s):  
Cell Line ◽  
Insulin Action ◽  
Glycogen Synthase ◽  
Biological Activities ◽  
Hepatoma Cell ◽  
Insulin Receptors ◽  
Hepatoma Cell Line ◽  
Response Curves ◽  
Cell Hybrids ◽  
L Cell

The expression of insulin receptors and insulin action was studied in cell hybrids and cybrids produced by fusion of the BWIJ mouse hepatoma cell line with nucleated and enucleated mouse L-cells (LEA-2A) respectively. The BWIJ parent and the cybrids expressed high numbers of insulin receptors, whereas the hybrids resembled the L-cell parent with low numbers of receptors. Likewise, the hybrids resembled the LEA-2A cells with high levels of glycogen synthase, whereas the BWIJ cells and cybrids had much lower levels. Both parents, the cybrids, and the hybrids, expressed insulin stimulation of alpha-aminoisobutyric acid influx, but the dose-response curves indicated an increased insulin sensitivity in the cells with the higher receptor concentration. Insulin also stimulated 86Rb+ uptake in the hepatoma parent, hybrids and cybrids, but not in the L-cell parent. These data suggest that insulin receptors, like other hepatoma-specific properties, behave as a ‘luxury function’ of the hepatoma cell line and are extinguished when the hepatoma cell is fused with a less differentiated cell type. The biological activities associated with insulin action, on the other hand, are much more complex in their expression and probably the result of the interaction of multiple factors that vary in their expression in cell hybrids and cybrids.

Glucocorticoid and developmental regulation of amylase mRNAs in mouse liver cells

1988 ◽  
Vol 8 (9) ◽  
pp. 3857-3863
Author(s):  
L C Samuelson ◽  
P R Keller ◽  
G J Darlington ◽  
M H Meisler
Keyword(s):  
Cell Line ◽  
Mouse Liver ◽  
Hepatoma Cell ◽  
Hepatoma Cells ◽  
Liver Cells ◽  
Mouse Serum ◽  
Hepatoma Cell Line ◽  
Glucocorticoid Treatment ◽  
Mouse Tissues

We characterized alpha-amylase expression in the hepatoma cell line Hepa 1-6 and in normal mouse liver. Both Amy-1 and Amy-2 were expressed in Hepa 1-6 and were regulated by glucocorticoids. Transcription in the hepatoma cells was initiated at the same start sites as in mouse tissues. Glucocorticoid treatment increased the abundance of Amy-1 and Amy-2 transcripts by 10 to 20-fold. This increase was detected within 4 h and was maximal by 24 h. The pattern of amylase expression in this hepatoma cell line accurately reflects amylase expression in the liver in vivo. During liver development, we observed a large increase in the abundance of Amy-1 transcripts just before birth, at a time when circulating glucocorticoids are also elevated. Adult mouse liver expressed Amy-1 and Amy-2 at levels comparable to those of fully induced hepatoma cells. Liver is thus a likely source of both amylase isozymes in mouse serum. These studies demonstrate that Amy-2 expression is not limited to the pancreas but also occurs at a low level in liver cells.

scholarly journals Resistance to the apoptotic effect of aggregated amyloid-β peptide in several different cell types including neuronal- and hepatoma-derived cell lines

1998 ◽  
Vol 332 (2) ◽  
pp. 517-524 ◽  
Author(s):  
Mark MAZZIOTTI ◽  
David H. PERLMUTTER
Keyword(s):  
Cell Death ◽  
Cell Line ◽  
Hepatoma Cell ◽  
Amyloid Β ◽  
Cell Types ◽  
Hepatoma Cell Line ◽  
Parent Cell ◽  
Amyloid Β Peptide ◽  
Aβ Peptide ◽  
Apoptotic Effect

There is a large body of literature indicating that aggregated amyloid-β peptide (Aβ) is toxic to neurons and suggesting that this neurotoxicity represents the final common pathway for neuronal degeneration in Alzheimer's disease. Previous studies have shown the outgrowth of a subclone of the rat neuronal cell line PC12 that is resistant to the toxic effect of aggregated Aβ peptide if the parent cell line is grown in the presence of aggregated Aβ peptide for a number of passages [Behl, Davis, Lesley and Schubert (1994) Cell 77, 817–827; Boland, Behrens, Choi, Manias and Perlmutter (1996) J. Biol. Chem. 271, 18032–18044]. To begin to characterize the mechanism by which PC12 cells become resistant to the apoptotic effect of Aβ peptide, in the present study we examined whether the resistance was specific to aggregated peptides, specific to an apoptotic form of cell death, and specific in cell type or was a general resistance to cell death that could be elicited in diverse cell types. The results show that the resistance is specific to compounds that have apoptotic effects through the generation of hydroxyl radical or H2O2, including aggregated Aβ-(25–35), Aβ-(1–40), Aβ-(1–42), Aβ-(1–43), amylin, 6-hydroxydopamine and H2O2 itself. The resistant subclones of PC12 were not resistant to other forms of apoptotic cell death or to necrotic cell death. The resistant state was also identified in a human hepatoma cell line, HepG2, when it was grown in the presence of aggregated Aβ-(25–35) for several passages, indicating that the mechanism(s) or molecule(s) responsible for this resistance are not restricted to neuronal cells and may be relevant to the pathobiology of oxidative injury in other cell types.

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