Saccharomyces cerevisiae as an eukaryotic cell model to assess cytotoxicity and genotoxicity of three anticancer anthraquinones.
The toxicity of most drugs is associated with their enzymatic conversion to toxic metabolites. Bioactivation reactions occur in a range of cellular organs and organelles, including mitochondria. We have investigated different effects (i.e. growth inhibition, mortality and genotoxicity) of doxorubicin, epirubicin and mitoxantrone on the D7 strain of Saccharomyces cerevisiae and on its petite (rho degrees ) respiratory-deficient mutant at various cellular concentrations of cytochrome P450 and glutathione (GSH). The data confirmed the importance of oxygen production for doxorubicin toxicity. The complete absence, or a very low level, of cytochrome oxidase subunit IV conferred some resistance to doxorubicin. Low GSH levels decreased resistance to doxorubicin in both strains, suggesting that thiol depletion could potentiate membrane lipid peroxidation. Doxorubicin induction of petite colonies suggests that the drug is able to select rather than induce respiratory-deficient mutants. Epirubicin induced levels of cytotoxicity similar to those of doxorubicin. The effects did not appear to be significantly dependent on mitochondrial function or GSH levels, whereas cells were strongly protected by cytochrome P450. GSH did not induce an evident alteration. Neither were genotoxic effects induced. Mitoxantrone had reduced levels of both growth inhibition and cytotoxicity in comparison to anthracyclines and induced convertants, revertants and aberrants. All the effects considered were amplified at high cytochrome P450 cellular concentrations, although the drug was also shown to act without previous metabolism via cytochrome P450. Anthracenedione effectiveness was increased by metabolism via cytochrome P450 and partially reduced by GSH. However, further mechanisms were suggested, which might implicate mitochondrial function and/or production of electrophilic cytotoxic and/or genotoxic intermediates by means of GSH conjugation. The biological effectiveness of doxorubicin, epirubicin and mitoxantrone on S.cerevisiae was shown to be strictly dependent on cell-specific physiological/biochemical conditions, such as a functional respiratory chain and levels of cytochrome P450 and GSH.
Buschini
Annamaria
A
Istituto di Genetica, Università degli Studi di Parma, Parco Area delle Scienze 11/a, 43100 Parma, Italy.
Poli
Paola
P
Rossi
Carlo
C
D000970:Antineoplastic Agents / Q000378:metabolism / Q000633:toxicity*; D001711:Biotransformation; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D003573:Cytochrome b Group / Q000032:analysis; D003574:Cytochrome c Group / Q000032:analysis; D004272:DNA, Mitochondrial / Q000187:drug effects / Q000235:genetics; D004317:Doxorubicin / Q000378:metabolism / Q000633:toxicity*; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D015251:Epirubicin / Q000378:metabolism / Q000633:toxicity*; D005785:Gene Conversion / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D008942:Mitoxantrone / Q000378:metabolism / Q000633:toxicity*; D009152:Mutagenicity Tests; D010101:Oxygen Consumption / Q000235:genetics; D017354:Point Mutation / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism
D000970:Antineoplastic Agents; D003573:Cytochrome b Group; D003574:Cytochrome c Group; D004272:DNA, Mitochondrial; D029701:Saccharomyces cerevisiae Proteins; D015251:Epirubicin; D004317:Doxorubicin; D003577:Cytochrome P-450 Enzyme System; D008942:Mitoxantrone; D003576:Electron Transport Complex IV; D005978:Glutathione