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Transport of methotrexate into LNCaP human prostate cancer cells
Author(s) -
Horne Donald W.,
Reed Kathleen A.
Publication year - 2002
Publication title -
biofactors
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 94
eISSN - 1872-8081
pISSN - 0951-6433
DOI - 10.1002/biof.5520160103
Subject(s) - lncap , methotrexate , probenecid , chemistry , prostate cancer , dids , pharmacology , cancer cell , biochemistry , medicine , cancer , membrane
Uptake of methotrexate into the LNCaP human prostate cancer cells was linear for the first 60∼min. The initial rate of methotrexate uptake was highest at extracellular pH 4.5 and decreased markedly until pH 7.0 to 8.0. Transport of methotrexate into LNCaP cells showed two components, one saturable ‐K m = 0.13 ± 0.06 μM and V max = 1.20 ± 0.16 pmol · 45 min −1 · mg −1 protein at low concentrations and the other apparently not saturable up to 10 μM. Uptake of methotrexate was inhibited by structural analogs with the K i values being 6.53, 12.4, and 85.6 μM for 5‐formyltetrahydrofolate, 5‐methyltetrahydrofolate, and folic acid, respectively. Uptake of methotrexate into LNCaP cells was not inhibited by the energy poisons in contrast to methotrexate uptake into PC‐3 prostate cancer cells. Uptake was inhibited by increasing concentrations of sulfate and phosphate ions and by the organic anions probenecid and DIDS, suggesting that methotrexate may be transported by an anion‐exchange mechanism. These results show that methotrexate is transported into LNCaP prostate cancer cells by a carrier‐mediated process.