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The interaction of platinum antitumour drugs with mouse liver mitochondria
M Rosen1, M Figliomeni, H Simpkins
1Department of Pathology, Staten Island University Hospital, New York 10305.
Abstract:
A study was undertaken to determine if cis-DDP and its second generation derivatives produced effects on mouse liver mitochondria, and if any of the observed effects could be correlated with the nephrotoxicity of the drugs. Although changes were observed in mitochondrial morphology, enzyme activity, Ca2+ influx, terbium binding and surface potential, no specific effect was correlated with nephrotoxicity. cis-DDP produced marked changes in mitochondrial morphology; electron probe analysis showed binding of the drug to the mitochondria. Inhibition of complex I and II activity of the respiratory chain and an ionic-strength-dependent effect on Tb3+ (a Ca2+ analogue) fluorescence were observed. The non-nephrotoxic derivatives, CHIP and tetraplatin, also produced significant changes in morphology. Treatment with these derivatives also produced decreases in mitochondrial enzyme activity, but the effect on terbium binding had an ionic-strength dependence which was inverse to that observed with cis-DDP. The tetravalent compounds also had a notable effect on mitochondrial surface potential. Carboplatin had an effect on morphology and Ca2+ influx and it inhibited the respiratory enzymes, although in a manner different from that observed with cis-DDP. Carboplatin had a minimal effect on terbium binding. It is evident that if the platinum drugs enter a cell to exert their action at the nuclear level, they will also depress mitochondrial function. The observed effects did not correlate with nephrotoxicity but, since all four compounds significantly altered mitochondrial structure and function, they may be related to the cytotoxicity of the drug.
Insights
Platinum drugs like cis-DDP and its derivatives impact mouse liver mitochondria function and morphology. However, these observed mitochondrial effects did not correlate with drug-induced kidney toxicity.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Platinum-based drugs are widely used chemotherapy agents.
- Understanding their cellular mechanisms and side effects is crucial for improving cancer treatment.
- Mitochondria play a key role in cellular health and drug-induced toxicity.
Purpose of the Study:
- To investigate the effects of cis-diamminedichloroplatinum(II) (cis-DDP) and its second-generation derivatives on mouse liver mitochondria.
- To determine if observed mitochondrial changes correlate with the nephrotoxicity of these platinum compounds.
Main Methods:
- Mitochondrial morphology was assessed using electron microscopy.
- Enzyme activity of the respiratory chain (Complex I and II) was measured.
- Calcium (Ca2+) influx and terbium (Tb3+) binding were analyzed.
- Mitochondrial surface potential was evaluated.
Main Results:
- Cis-DDP induced significant changes in mitochondrial morphology and inhibited respiratory enzymes.
- Non-nephrotoxic derivatives (CHIP, tetraplatin) also altered mitochondrial morphology and enzyme activity.
- All tested platinum compounds affected mitochondrial structure and function, but effects did not correlate with nephrotoxicity.
- Carboplatin showed distinct effects on Ca2+ influx and enzyme inhibition compared to cis-DDP.
Conclusions:
- Platinum drugs, including cis-DDP and its derivatives, significantly impact mitochondrial structure and function.
- The observed mitochondrial alterations are likely related to the general cytotoxicity of these drugs, rather than specific nephrotoxicity.
- Further research is needed to elucidate the precise mechanisms linking platinum drugs to cellular damage.