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Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A cross has been performed between dedifferentiated rat hepatoma cells and the differentiated cells from which they were derived. 10 hybrid clones, containing the complete chromosome sets of both parents, show extinction of 4 liver-specific enzymes: tyrosine aminotransferase (E.C. 2.6.1.5), alanine aminotransferase (E.C. 2.6.1.2), and the liver-specific isozymes of alcohol dehydrogenase (E.C. 1.1.1.1) and aldolase (E.C. 4.1.2.13). Moreover, the 4 hybrid clones examined do not produce albumin . The only function of the differentiated parent which is not extinguished in the hybrid cells is inducibility of the aminotransferases. For 3 of the hybrid clones, extinction of 3 of the 4 enzymes is incomplete, but these clones do not differ in modal chromosome number from those which show more complete extinction of the enzymes. Subcloning of several of the hybrids revealed that the phenotype of the hybrids is very stable; 4 subclones showing reexpression of intermediate levels of the enzymes are characterized. These results show that dedifferentiation of the parental cells is not due to the simple loss of some factor required for the maintenance of expression of differentiated functions, and suggest that dedifferentiation is due to the activation of some control mechanism, whose final effect is negative, and which may be a part of the epigenotype of the embryonic hepatocyte.
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PMID:Extinction of liver-specific functions in hybrids between differentiated and dedifferentiated rat hepatoma cells. 1 65

Hybridization of cells of defined and different histotypes has been carried out to investigate whether the expression (or reexpression) of parental functions is mutually exclusive, as is expected if the generally assumed rule of discreteness of differentiation applies to hybrid cells. A cross of pigmented mouse melanoma cells and albumin-producing rat hepatoma cells gave rise to hybrids containing essentially one set of chromosomes from each parent and producing neither melanin nor albumin. Cells of one hybrid clone are shown to retain the potential to reexpress both parental differentiations. Successive subclonings of this hybrid have shown that cells which reexpress one function may retain the potential to reexpress the other, and that freshly isolated, morphologically homogeneous subclones may produce pigment or albumin, but not both; there successive and exclusive shifts of phenotype are documented, and in these cases, chromosome loss is very slight. The use of immunoadsorbed antisera has revealed that most (if not all) of the albumin produced by the hybrid cells is of the mouse type. We conclude that both parental determinations are retained by the hybrid cells, and that the parental differentiations are reexpressed only in a mutually exclusive fashion.
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PMID:Phenotypic exclusion in mouse melanoma-rat hepatoma hybrid cells: pigment and albumin production are not reexpressed simultaneously. 3 79

We have produced somatic cell hybrids between totipotent mouse teratocarcinoma cells and rat hepatoma cells. These hybrids were tested for the expression of liver specific functions expressed in the hepatoma cell parent and for their ability to differentiate when injected into nude mice. The results of this study indicate that hybrid cell clones do not resemble either of the parental cells, since they do not produce albumin and tyrosine aminotransferase that are expressed in the rat hepatoma parent, and are incapable of forming either teratocarcinomas or hepatomas when injected in experimental animals.
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PMID:Somatic cell hybrids between totipotent mouse teratocarcinoma and rat hepatoma cells. 4 96

Hybrids between mouse hepatoma cells (which secrete several serum proteins) and mouse or rat fibroblasts (which do not secrete these proteins) produce transferrin and the third component of complement (C3) like the parental hepatoma cells, while they do not secrete either albumin or alpha-fetoprotein (AFP). This lack of albumin and AFP secretion is probably due to a lack of synthesis, rather than to a simple defect in secretion. The cessation of albumin and AFP production is not dependent upon the parental fibroblast nor upon the selection conditions; it is best explained by a shut-off synthesis and could thus reflect the existence of a regulatory mechanism. This would imply a difference between the control of albumin and AFP synthesis and that of transferrin and C3 synthesis. On the other hand, in agreement with Peterson and Weiss (1972), hybrids between rat hepatoma cells and mouse fibroblasts continue to product rat albumin. This suggests that the mouse hepatoma cells differ from the rat hepatoma cells in the way they control albumin production.
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PMID:The control of serum protein synthesis in hepatoma-fibroblast hybrids. 5 90

A permanent cell line (BW) was established from a transplantable mouse hepatoma, BW7756, which produces alpha-foetoprotein (AFP). Three clones were isolated from the uncloned culture: BW1, BW2 and BWTG3. The cells of the latter clone, which was isolated after selection in the presence of thioguanine, are deficient in the enzyme hypoxanthine-guanine-phosphoribosyl transferase. Both BW1 and BWTG3 cells have mean chromosome number of 64 (60 telocentric and 4 metacentric chromosomes). All three clones secrete at least five serum proteins into the culture medium: albumin, AFP, and alpha 2 globulin, transferrin and C3, the third component of complement. The approximate rate of albumin secretion by BW1 and BWTG3 cells is 10 mug/24 h/10(6) cells. Both albumin and AFP can easily be detected in cell extracts. The simultaneous production of AFP and a hepatocyte specific marker (albumin) by cloned hepatoma cells show that the production of AFP by the tumour is due to the tumoural hepatocytes themselves.
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PMID:A mouse hepatoma cell line which secretes several serum proteins including albumin and alpha-foetoprotein. 5 68

The synthesis of alpha-fetoprotein and albumin in two clones of AH66 hepatoma was studied. (1) Amounts of AFP and albumin synthesized by the C-4 clone were 2.9 and 0.28 X 10(-7) mug per cell per hour, respectively. AFP and albumin amounts synthesized by the A-1 clone were 2.5 and 1.8 X 10(-7) mug per cell per hour, respectively. (2) The cell cycles of the C-4 and A-1 clones were as follows: C-4 clone: mean generation time 20.5 hours: G1, 10 hours; S, 7 hours; G2, 4 hours; and M, 30 minutes. A-1 clone: mean generation time 50.7 hours: G1, 36 hours; S, 10 hours; G2, 4 hours; and M, 30-60 minutes. (3) AFP was found to be synthesized from late G1 phase to the end of the S phase for 9 hours in C-4 and 25 hours in A-1. The albumin production was from late S phase to the beginning of the G2 phase for 4 hours in C-4 and 9 hours in A-1, which were approximately half or one-third of the time spent on AFP production. (4) The double staining with fluorescent-conjugated antibodies to AFP and albumin demonstrated that AFP and albumin are probably synthesized by different cells.
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PMID:Alpha-Fetoprotein and albumin synthesis during the cell cycle. 5 32

The alpha-fetoprotein (AFP) and albumin localization were studied in the cells of rat Zaidel's ascitic hepatoma. It was shown in the paraffine sections of the hepatoma cells fixed by mixture of 96 degrees ethanol with 1% glacial acetic acid that 9.3% of hepatoma cells contained AFP and 0.6% of the cells--serum albumin. Small quantities of the tumour cells had both of these proteins simultaneously. There was no definite regularity in the distribution of the AFP and albumin-containing cells in the tumour islands.
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PMID:[Distribution of alpha-fetoprotein and albumin in paraffin sections of cells of Zaidel's ascitic hepatoma]. 5 59

Subclonal cell populations were prepared from a clonal line of the rat ascites hepatoma AH-66 in vitro, using the agar plate culture method. alpha-Fetoprotein and albumin concentrations in culture media of these subclones were determined by 125I-radioimmunoassay and single radial immunodiffusion method, respectively. Results demonstrated that the AH-66 clone was a complex of cells with varying producibility of alpha-fetoprotein and albumin. All the subclones showed varied and distinct production of alpha-fetoprotein, but not all the subclones produced detectable levels of albumin.
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PMID:Alpha-fetoprotein and albumin produced by subclonal cell population of the ascites hepatoma AH-66 in vitro. 5 95

The production of four serum proteins has been analysed in several hepatoma-fibroblast hybrids. Extinction of albumin and alpha-foetoprotein production occurs systematically in intra and interspecific (rat X mouse) hybrids derived from mouse hepatoma cells (BW). Similar hybrids derived from two related clones of rat hepatoma cells either do not produce albumin (Fa32-derived hybrids), as the BW-derived hybrids, or retain the capacity to produce it, but at a reduced rate (Fu5-derived hybrids); some differences in the control of albumin production thus seem to exist between clonal hepatoma cell lines. The mouse hepatoma cell hybrids retain the capacity to secrete transferrin at a reduced rate, and C3 (the third component of complement) at a high rate. Further analysis of C3 production in interspecific hybrids showed that both parental genomes actively contribute to C3 production: induction of C3 secretion is thus observed in these hybrids.
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PMID:Extinction, retention and induction of serum protein secretion in hepatoma-fibroblast hybrids. 6 Nov 42

Serum alpha-globulin fractions isolated by physiocochemical techniques from normal adult Buffalo rats suppressed lymphocyte proliferation in vitro. The factors responsible for mixed lymphocyte culture suppression appeared to be strain specific since they were not demonstrable in the same fractions from normal LBN rat serum. Similar fractionation of the serum from Buffalo rats bearing the Morris Hepatoma 7777 obtained from two different sources also yielded suppressive protein fractions that differed both chemically and functionally. Both variants of this hepatoma produced high serum concentrations of alpha-fetoprotein (AFP), providing an opportunity to study the possible immunoregulatory role of their fetal-associated globulins. Fractions rich in AFP that lacked other serum alpha-globulins were obtained by gel filtration chromatography and were devoid of any in vitro immunosuppressive activity. When AFP that was further purified by immunoabsorption was added to mixed lymphocyte cultures, no effect was observed at doses below 400 mug/ml. The MLC response was augmented with higher doses, similar to albumin purified by the same methods.
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PMID:Effect of alpha-fetoprotein and other serum factors derived from hepatoma-bearing rats on the mixed lymphocyte response. 6 91


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