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Updated: Oct 13, 2026

Expression, Detergent Solubilization, and Purification of a Membrane Transporter, the MexB Multidrug Resistance Protein
10:43

Expression, Detergent Solubilization, and Purification of a Membrane Transporter, the MexB Multidrug Resistance Protein

Published on: December 3, 2010

Role of membrance transport in the pharmacologic action of antifolates

F M Sirotnak

    Cancer Treatment Reports
    |January 1, 1981
    PubMed

    Insights

    Mice tissues show varying folate analog accumulation, impacting drug effectiveness. Differences in retention and DNA synthesis inhibition explain selective antitumor activity in folate analog cancer therapy.

    Area of Science:

    • Pharmacology
    • Molecular Biology
    • Oncology

    Background:

    • Folate analogs are used in cancer therapy.
    • Intracellular folate analog levels vary across tissues.
    • This variation affects drug efficacy and selectivity.

    Purpose of the Study:

    • To investigate the differential accumulation and retention of folate analogs in various proliferative tissues in mice.
    • To understand the relationship between tissue-specific pharmacokinetics and the selective antitumor effects of folate analogs.
    • To elucidate the role of carrier-mediated transport in these pharmacokinetic differences.

    Main Methods:

    • Comparative analysis of folate analog accumulation and retention in normal (small intestine, bone marrow) and tumor tissues in murine models.
    • Assessment of DNA synthesis inhibition in response to folate analogs across different tissues.
    • Investigation of the structural specificity of carrier-mediated membrane transport for folate analogs.

    Main Results:

    • Significant differences in intracellular folate analog accumulation and retention were observed among proliferative tissues.
    • The small intestine demonstrated higher sensitivity to folate analogs than bone marrow due to greater drug retention and prolonged DNA synthesis inhibition.
    • Responsive tumors exhibited greater drug retention and more prolonged DNA synthesis inhibition compared to nonresponsive tumors and the small intestine, accounting for selective antitumor action.
    • Pharmacokinetic variations were primarily attributed to the structural specificity of carrier-mediated membrane transport.

    Conclusions:

    • Tissue-specific pharmacokinetics, particularly drug retention and transport mechanisms, are critical determinants of folate analog efficacy and selectivity.
    • Carrier-mediated membrane transport plays a key role in the differential distribution and action of folate analogs in normal and tumor tissues.
    • Understanding these pharmacokinetic differences can guide the development of more targeted and effective folate analog-based cancer therapies.

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