Increased oxidative stress and apoptosis have been implicated in the cardiotoxicity that limits the clinical use of doxorubicin (DOX) as an anti-tumoral drug, but the mechanism of DOX-mediated apoptosis remains unclear. We examined the interplay between oxidative stress and cell death in cardiac-derived H9c2 myocytes exposed to DOX doses in the range of the plasma levels found in patients undergoing chemotherapy. A low DOX concentration (0.25 μM) induced apoptosis, whereas the cells treated with the high dose of 2 μM also showed necrosis. The production of reactive oxygen species (ROS) and induction of oxidative stress markers was increased in the cells treated with 2 μM DOX but not in those treated with the low dose. Surprisingly, heme oxygenase (HO-1) expression was down-modulated in the cells exposed to 0.25 μM DOX, and its Bach 1 transcriptional repressor was induced. In line with the role of HO-1 as an anti-apoptotic protein, inhibiting HO-1 activity with SnPPIX was sufficient to induce apoptosis and increased DOX-mediated apoptosis, whereas hemin-induced HO-1 activation prevented DOX-mediated apoptotic cell death. In brief, our findings do not support the hypothesis that oxidative stress plays a role in the apoptotic cell death occurring in cardiomyocytes exposed to low concentrations of DOX, but suggest that DOX may facilitate the apoptosis of cardiomyocytes by inhibiting the anti-apoptotic HO-1. © 2008 Elsevier Ireland Ltd. All rights reserved
Bernuzzi, F., Recalcati, S., Alberghini, A., Cairo, G. (2009). Reactive oxygen species-independent apoptosis in doxorubicin-treated H9c2 cardiomyocytes: Role for heme oxygenase-1 down-modulation. CHEMICO-BIOLOGICAL INTERACTIONS, 177(1), 12-20 [10.1016/j.cbi.2008.09.012].
Reactive oxygen species-independent apoptosis in doxorubicin-treated H9c2 cardiomyocytes: Role for heme oxygenase-1 down-modulation
Bernuzzi, Francesca Veronica;
2009
Abstract
Increased oxidative stress and apoptosis have been implicated in the cardiotoxicity that limits the clinical use of doxorubicin (DOX) as an anti-tumoral drug, but the mechanism of DOX-mediated apoptosis remains unclear. We examined the interplay between oxidative stress and cell death in cardiac-derived H9c2 myocytes exposed to DOX doses in the range of the plasma levels found in patients undergoing chemotherapy. A low DOX concentration (0.25 μM) induced apoptosis, whereas the cells treated with the high dose of 2 μM also showed necrosis. The production of reactive oxygen species (ROS) and induction of oxidative stress markers was increased in the cells treated with 2 μM DOX but not in those treated with the low dose. Surprisingly, heme oxygenase (HO-1) expression was down-modulated in the cells exposed to 0.25 μM DOX, and its Bach 1 transcriptional repressor was induced. In line with the role of HO-1 as an anti-apoptotic protein, inhibiting HO-1 activity with SnPPIX was sufficient to induce apoptosis and increased DOX-mediated apoptosis, whereas hemin-induced HO-1 activation prevented DOX-mediated apoptotic cell death. In brief, our findings do not support the hypothesis that oxidative stress plays a role in the apoptotic cell death occurring in cardiomyocytes exposed to low concentrations of DOX, but suggest that DOX may facilitate the apoptosis of cardiomyocytes by inhibiting the anti-apoptotic HO-1. © 2008 Elsevier Ireland Ltd. All rights reserved
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