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Multidrug resistance and mutagenesis
1Cancer Research Laboratory, University of Auckland School of Medicine, New Zealand.
Abstract:
Multidrug resistance, the phenomenon whereby the development of resistance to one drug is sometimes accompanied by the simultaneous development of resistance to a variety of other, often structurally unrelated, drugs, is frequently associated with the presence of an energy-dependent membrane-transport system which reduces the concentration of a drug or other chemical in the cytoplasm. The latter process (termed here MDR) occurs naturally in a number of normal mammalian tissues, including colon, jejunum, liver, kidney and bone marrow, as well as in other species including bacteria. The presence of MDR can reduce the mutagenic potential of a variety of compounds in mammalian and microbiological assays. MDR can be reversed by a diverse collection of compounds, many of which are hydrophobic cations with other physiological effects. An important consequence of these considerations is that MDR-reversing agents are potentially dangerous because, while having no intrinsic mutagenicity, they may significantly increase the mutagenicity of other compounds by poisoning protective MDR mechanisms in the body.
Insights
Multidrug resistance (MDR) involves resistance to multiple drugs, often due to cellular efflux pumps. MDR-reversing agents can increase drug efficacy but may also enhance the mutagenicity of other compounds.
Area of Science:
- Biochemistry
- Pharmacology
- Cell Biology
Background:
- Multidrug resistance (MDR) is a phenomenon where cells become resistant to various drugs simultaneously.
- This resistance is often linked to energy-dependent membrane transport systems that reduce intracellular drug concentrations.
- MDR occurs naturally in mammalian tissues and bacteria, playing a role in cellular protection.
Purpose of the Study:
- To explore the mechanisms and implications of multidrug resistance (MDR).
- To investigate the role of MDR in modulating the mutagenic potential of chemical compounds.
- To assess the safety and efficacy of MDR-reversing agents.
Main Methods:
- Analysis of energy-dependent membrane transport systems.
- Evaluation of MDR's effect on mutagenicity in mammalian and microbiological assays.
- Assessment of MDR reversal by various compounds, including hydrophobic cations.
Main Results:
- MDR can naturally reduce the mutagenic potential of compounds.
- MDR-reversing agents, while not mutagenic themselves, can increase the mutagenicity of other substances.
- This occurs by inhibiting protective MDR mechanisms within the body.
Conclusions:
- MDR is a complex biological process with implications for drug efficacy and toxicity.
- MDR-reversing agents require careful consideration due to their potential to enhance compound mutagenicity.
- Understanding MDR mechanisms is crucial for developing safer and more effective therapeutic strategies.