PT  - JOURNAL ARTICLE
AU  - Emanuela Salvatorelli
AU  - Pierantonio Menna
AU  - Sabrina Cascegna
AU  - Giovanni Liberi
AU  - Antonio M. Calafiore
AU  - Luca Gianni
AU  - Giorgio Minotti
TI  - Paclitaxel and Docetaxel Stimulation of Doxorubicinol Formation in the Human Heart: Implications for Cardiotoxicity of Doxorubicin-Taxane Chemotherapies
AID  - 10.1124/jpet.106.103846
DP  - 2006 Jul 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 424--433
VI  - 318
IP  - 1
4099  - http://jpet.aspetjournals.org/content/318/1/424.short
4100  - http://jpet.aspetjournals.org/content/318/1/424.full
SO  - J Pharmacol Exp Ther2006 Jul 01; 318
AB  - Antitumor therapy with the anthracycline doxorubicin is limited by a dose-related cardiotoxicity that is aggravated by a concomitant administration of the taxane paclitaxel. Previous limited studies with isolated human heart cytosol showed that paclitaxel was able to stimulate an NADPH-dependent reduction of doxorubicin to its toxic secondary alcohol metabolite doxorubicinol. Here we characterized that 0.25 to 2.5 μM paclitaxel caused allosteric effects that increased doxorubicinol formation in human heart cytosol, whereas 5 to 10 μM paclitaxel decreased doxorubicinol formation. The closely related taxane docetaxel caused similar effects. Basal or taxane-stimulated doxorubicinol formation was blunted by 2,7-difluorospirofluorene-9,5′-imidazolidine-2′,4′-dione (AL1576), a specific inhibitor of aldehyde reductases. Doxorubicinol was measured also in the cytosol of human myocardial strips incubated in plasma and exposed to doxorubicin in the absence or presence of paclitaxel or docetaxel and their clinical vehicles Cremophor EL or polysorbate 80. Low concentrations of taxanes stimulated doxorubicinol formation, whereas high concentrations decreased it. Doxorubicinol formation reached its maximum on adding plasma with 6 μM paclitaxel or docetaxel; this corresponded to the partitioning of 1.5 to 2.5 μM taxanes in the cytosol of the strips. Taxane-stimulated doxorubicinol formation was not mediated by vehicles, nor was it caused by increased doxorubicin uptake or de novo protein synthesis; however, doxorubicinol formation was blunted by AL1576. These results show that allosteric interactions with cytoplasmic aldehyde reductases enable paclitaxel or docetaxel to stimulate doxorubicinol formation in human heart. This information serves metabolic insights into the risk of cardiotoxicity induced by doxorubicin-taxane therapies. The American Society for Pharmacology and Experimental Therapeutics