Enhancement of methotrexate resistance and dihydrofolate reductase gene amplification by treatment of mouse 3T6 cells with hydroxyurea.
AUTOR(ES)
Brown, P C
RESUMO
We investigated various parameters associated with the initial selection of mouse 3T6 cells for resistance to single concentrations of methotrexate and characterized resistant colonies for the presence of additional (amplified) copies of the dihydrofolate reductase gene. Our results indicate that the frequency of occurrence of dihydrofolate reductase gene amplification varies with the selecting concentration of methotrexate and is highly variable between clonally derived sublines of mouse 3T6 cells. Second, we increased the frequency of occurrence of cells with amplified dihydrofolate reductase genes by transiently inhibiting DNA synthesis with hydroxyurea before the selection of cells in single concentrations of methotrexate. This effect was dependent on the concentration of hydroxyurea, the time of exposure to the drug, and the time interval between the removal of hydroxyurea and the selection of cells in methotrexate.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=368639Documentos Relacionados
- UV radiation facilitates methotrexate resistance and amplification of the dihydrofolate reductase gene in cultured 3T6 mouse cells.
- Loss of unstably amplified dihydrofolate reductase genes from mouse cells is greatly accelerated by hydroxyurea.
- Overproduction of the free radical of ribonucleotide reductase in hydroxyurea-resistant mouse fibroblast 3T6 cells.
- P-glycoprotein confers methotrexate resistance in 3T6 cells with deficient carrier-mediated methotrexate uptake.
- Carcinogen-mediated methotrexate resistance and dihydrofolate reductase amplification in Chinese hamster cells.
