Corpus ID: 19692

5-Methyltetrahydrofolate transport by hepatoma cells and methotrexate-resistant sublines in culture.

@article{Galivan19815MethyltetrahydrofolateTB,
  title={5-Methyltetrahydrofolate transport by hepatoma cells and methotrexate-resistant sublines in culture.},
  author={John Galivan},
  journal={Cancer research},
  year={1981},
  volume={41 5},
  pages={
          1757-62
        }
}
  • J. Galivan
  • Published 1981
  • Biology, Medicine
  • Cancer research
The properties of the folate transport system in H35 hepatoma cells have been studied by measuring the transport of (+)-5-methyltetrahydrofolate. Using initial rates of uptake, it has been demonstrated that the uptake is saturable, carrier mediated, and shared by methotrexate. The accumulation of (+)-5-methyltetrahydrofolate is concentrative, demonstrating the presence of an active transport process. A previous study suggested that methotrexate-resistant sublines (H35R) acquired methotrexate… Expand
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Identification of a membrane-associated folate-binding protein in human leukemic CCRF-CEM cells with transport-related methotrexate resistance.
TLDR
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  • Biology, Medicine
  • Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine
  • 1993
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Factors controlling the concentrations of methotrexate in cultured hepatic cells.
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Hormonal alteration of methotrexate and folate polyglutamate formation in cultured hepatoma cells.
  • J. Galivan
  • Biology, Medicine
  • Archives of biochemistry and biophysics
  • 1984
TLDR
The results suggest that these hormones play a role in the glutamylation of the folate coenzymes in a liver-derived transformed cell line in culture and that these effects are also reflected in the interaction of the cells with antifolates such as methotrexate. Expand
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TLDR
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TLDR
Although defective MTX transport appeared to be correlated with the disappearance of GGT activity in an H35 variant cell line, no functional relationship between them is apparent at this time, and it is possible that a lack of G GT activity may be evidence of a more differentiated phenotype in the transport‐resistant cell line. Expand
Interaction of methotrexate poly(L-lysine) with transformed hepatic cells in culture.
TLDR
The role of poly( l -lysine) as a carrier was demonstrated, since methotrexate uptake was inhibited by folinic acid, which had no effect on the cells' uptake or hydrolysis of [ 3 H]methotrexate poly( d-lysine). Expand
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TLDR
The observation that azide enhances net MTX uptake in resistant as well as sensitive L5178Y cells along with findings in other studies that the net uptake of folic acid is enhanced by azide raises the possibility that the effects of metabolic inhibitors on net transport of MTX and folic Acid may be mediated, at least in part, by inhibition of a common exit process. Expand
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The results suggest that the cells become resistant as a result of a stable change in the transport system for MTX, but the mechanism of this process is not yet understood. Expand
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Kinetic analysis revealed an increase in the Michaelis constant for the system in these resistant cells, suggesting an alteration in the binding properties of a carrier component as the basis for the impairment. Expand
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  • J. Galivan
  • Biology, Medicine
  • Molecular pharmacology
  • 1980
TLDR
Protection studies demonstrated that both thymidine and hypoxanthine are needed to prevent methotrexate toxicity, offering evidence that inhibition of cell growth is due to a depletion of reduced folate coenzymes, and results demonstrate that the polyglutamates have at least an equivalent affinity for the enzyme in the intact cell when compared to metotrexate. Expand
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TLDR
It seems that resistance involving impaired methotrexate transport during treatment of human malignant disease may be a comparatively frequent phenomenon, and may occur together with elevation of dihydrofolate reductase activity. Expand
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TLDR
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SITES OF ACTION OF AMETHOPTERIN: INTRINSIC AND ACQUIRED DRUG RESISTANCE *
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Results are presented of some preliminary experiments designed to investigate further the likelihood that any variation between tumor cell strains in the K, and K, values for enzymes inhibited by MTX might then be expected to influence the overall cytotoxicity of the drug. Expand
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